Trent Woodruff

Complement components are upregulated and correlate with disease progression in the TDP-43 ^Q331K mouse model of amyotrophic lateral sclerosis

Publisher: Springer Science and Business Media LLC

Date: 06-2018

DOI: 10.1186/S12974-018-1217-2

THE CONCISE GUIDE TO PHARMACOLOGY 2021/22: G protein-coupled receptors.

Publisher: Wiley

Date: 16-09-2021

DOI: 10.1111/BPH.15538

Abstract: The Concise Guide to PHARMACOLOGY 2021/22 is the fifth in this series of biennial publications. The Concise Guide provides concise overviews, mostly in tabular format, of the key properties of nearly 1900 human drug targets with an emphasis on selective pharmacology (where available), plus links to the open access knowledgebase source of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties. Although the Concise Guide constitutes over 500 pages, the material presented is substantially reduced compared to information and links presented on the website. It provides a permanent, citable, point-in-time record that will survive database updates. The full contents of this section can be found at oi/bph.15538. G protein-coupled receptors are one of the six major pharmacological targets into which the Guide is ided, with the others being: ion channels, nuclear hormone receptors, catalytic receptors, enzymes and transporters. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. The landscape format of the Concise Guide is designed to facilitate comparison of related targets from material contemporary to mid-2021, and supersedes data presented in the 2019/20, 2017/18, 2015/16 and 2013/14 Concise Guides and previous Guides to Receptors and Channels. It is produced in close conjunction with the Nomenclature and Standards Committee of the International Union of Basic and Clinical Pharmacology (NC-IUPHAR), therefore, providing official IUPHAR classification and nomenclature for human drug targets, where appropriate.

Tissue-Type Plasminogen Activator and Tenecteplase-Mediated Increase in Blood Brain Barrier Permeability Involves Cell Intrinsic Complement

Publisher: Frontiers Media SA

Date: 08-12-2020

DOI: 10.3389/FNEUR.2020.577272

Abstract: Background: Tissue-type plasminogen activator (t-PA) has been the mainstay of therapeutic thrombolysis for patients with acute ischaemic stroke (AIS). However, t-PA can cause devastating intracerebral hemorrhage. t-PA can also influence the CNS in part by modulation of BBB permeability. Complement activation also occurs after AIS and has also been reported to increase BBB permeability. The complement components, C3 and C5, can also be activated by t-PA via plasmin formation and cell intrinsic complement may be involved in this process. Tenecteplase (TNK-tPA) is a t-PA variant with a longer plasma half-life, yet the ability of TNK-tPA to modulate the BBB and complement is less clear. Aim: To evaluate the effect of C5 and C5a-receptor 1 (C5aR1) inhibitors on t-PA- and TNK-tPA-mediated opening of the BBB. Methods: We used an in vitro model of the BBB where human brain endothelial cells and human astrocytes were co-cultured on the opposite sides of a porous membrane assembled in transwell inserts. The luminal (endothelial) compartment was stimulated with t-PA or TNK-tPA together with plasminogen, in the presence of PMX205 (a non-competitive C5aR1 antagonist), Avacopan (a competitive C5aR1 antagonist) or Eculizumab (a humanized monoclonal inhibitor of human C5). BBB permeability was assessed 5 and 24 h later. Immunofluorescence was also used to detect changes in C5 and C5aR1 expression in endothelial cells and astrocytes. Results: PMX205, but not Avacopan or Eculizumab, blocked t-PA-mediated increase in BBB permeability at both the 5 and 24 h time points. PMX205 also blocked TNK-tPA-mediated increase in BBB permeability. Immunofluorescence analysis revealed intracellular staining of C5 in both cell types. C5aR1 expression was also detected on the cell surfaces and also located intracellularly in both cell types. Conclusion: t-PA and TNK-tPA-mediated increase in BBB permeability involves C5aR1 receptor activation from cell-derived C5a. Selective inhibitors of C5aR1 may have therapeutic potential in AIS.

Benchmarking in pathology: Development of a benchmarking complexity unit and associated key performance indicators

Publisher: Elsevier BV

Date: 2013

DOI: 10.1097/PAT.0B013E32835B77C4

Complement mediators in ischemia–reperfusion injury

Publisher: Elsevier BV

Date: 12-2006

DOI: 10.1016/J.CCA.2006.06.010

Abstract: Ischemia-reperfusion (I/R) injury occurs when a tissue is temporarily deprived of blood supply and the return of the blood supply triggers an intense inflammatory response. Pathologically, increased complement activity can cause substantial damage to blood vessels, tissues and also facilitate leukocyte activation and recruitment following I/R injury. Herein, previously published studies are reported and critically reviewed. Medline and the World Wide Web were searched and the relevant literature was classified under the following categories: (1) Complement pathways (2) The complement system and the inflammatory response (3) Complement in ischemia-reperfusion injuries and (4) Therapeutic approaches against complement in I/R injuries. I/R injury is a common clinical event with the potential to seriously affect, and sometimes kill, the patient and is a potent inducer of complement activation that results in the production of a number of inflammatory mediators. Complement activation leads to the release of biologically active potent inflammatory complement substances including the anaphylatoxins (C3a and C5a) and the cytolytic terminal membrane attack complement complex C5b-9 (MAC). The use of specific complement inhibitors to block complement activation at various levels of the cascade has been shown to prevent or reduce local tissue injury after I/R. Several agents that inhibit all or part of the complement system, such as soluble complement receptor type 1 (sCR1), C1 inhibitor (C1-INH), C5a monoclonal antibodies, a C5a receptor antagonist and soluble CD59 (sCD59) have been shown to reduce I/R injury of various organs. The novel inhibitors of complement products may eventually find wide clinical application because there are no effective drug therapies currently available to treat I/R injuries.

Evaluating the model of offering expanded genetic carrier screening to high school students within the Sydney Jewish community

Publisher: Springer Science and Business Media LLC

Date: 30-11-2022

DOI: 10.1007/S12687-021-00567-8

Abstract: Programs offering reproductive genetic carrier screening (RGCS) to high school students within the Ashkenazi Jewish community in several countries including Canada and Australia have demonstrated high uptake and retention of educational messages over time. This study was undertaken to evaluate whether testing for an expanded number of conditions in a high school setting would impact the effectiveness of education. In this questionnaire-based study, genetic carrier testing for nine conditions was offered to 322 year 11 students from five high schools, with students attending a compulsory 1-h education session prior to voluntary testing. Comparison of pre- and post-education measures demonstrated a significant increase in knowledge, positive attitudes, and reduced concern immediately after the education session. Retention of knowledge, measures of positive attitude, and low concern over a 12-month period were significantly higher than baseline, although there was some reduction over time. In total, 77% of students exhibited informed choice regarding their intention to test. A significant increase in baseline knowledge scores and positive attitude was also demonstrated between our original 1995 evaluation (with testing for only one condition) and 2014 (testing for nine conditions) suggesting community awareness and attitudes to RGCS have increased. These findings validate the implementation of effective education programs as a key component of RGCS and are relevant as gene panels expand with the introduction of genomic technologies.

Low‐Fouling Fluoropolymers for Bioconjugation and In Vivo Tracking

Publisher: Wiley

Date: 03-02-2020

DOI: 10.1002/ANIE.201914119

Abstract: The conjugation of hydrophilic low-fouling polymers to therapeutic molecules and particles is an effective approach to improving their aqueous stability, solubility, and pharmacokinetics. Recent concerns over the immunogenicity of poly(ethylene glycol) has highlighted the importance of identifying alternative low fouling polymers. Now, a new class of synthetic water-soluble homo-fluoropolymers are reported with a sulfoxide side-chain structure. The incorporation of fluorine enables direct imaging of the homopolymer by

Microglial C5aR (CD88) expression correlates with amyloid-β deposition in murine models of Alzheimer’s disease

Publisher: Wiley

Date: 04-2010

DOI: 10.1111/J.1471-4159.2010.06595.X

Properdin deficiency protects from 5-fluorouracil-induced small intestinal mucositis in a complement activation-independent, interleukin-10-dependent mechanism

Publisher: Oxford University Press (OUP)

Date: 31-01-2017

DOI: 10.1111/CEI.12922

Abstract: Intestinal mucositis is a serious complication of chemotherapy that leads to significant morbidity that may require dose or drug adjustments. Specific mitigating strategies for mucositis are unavailable, due partly to an incomplete understanding of the pathogenic mechanisms. We have previously shown an effect of properdin, a positive regulator of complement activation, in models of colitis. Here we use properdin-deficient (PKO) mice to interrogate the role of properdin and complement in small intestinal mucositis. Mucositis was induced by five daily injections of 5-fluorouracil (5-FU) in wild-type (WT), PKO, interleukin (IL)-10–/– and properdin/IL-10–/– double knock-out (DKO) mice. At the time of euthanasia their jejunum was collected for histology, immunohistochemistry and cytokine and complement activation measurements. Complement became activated in mice receiving 5-FU, indicated by increased intestinal levels of C3a and C5a. Compared to WT, PKO mice experienced significantly less mucositis, despite C3a levels as high as inflamed WT mice and slightly less C5a. Conversely, PKO mice had higher intestinal levels of IL-10. IL-10 expression was mainly by epithelial cells in both uninflamed and inflamed PKO mice. IL-10–/– mice proved to be highly susceptible to mucositis and DKO mice were equally susceptible, demonstrating that a lack of properdin does not protect mice lacking IL-10. We interpret our findings to indicate that, to a significant extent, the inflammation of mucositis is properdin-dependent but complement activation-independent. Additionally, the benefit achieved in the absence of properdin is associated with increased IL-10 levels, and IL-10 is important in limiting mucositis.

The ‘C3aR antagonist’ SB290157 is a partial C5aR2 agonist

Publisher: Cold Spring Harbor Laboratory

Date: 03-08-2202

DOI: 10.1101/2020.08.01.232090

Abstract: Innate immune complement activation generates the C3 and C5 protein cleavage products C3a and C5a, defined classically as anaphylatoxins. C3a activates C3a receptors (C3aR), while C5a activates two receptors (C5aR1 and C5aR2) to exert their immunomodulatory activities. The non-peptide compound, SB290157, was originally reported in 2001 as the first C3aR antagonist. In 2005, the first report on non-selective nature of SB290157 was published, where the compound exerted clear agonistic, not antagonistic, activity in variety of cells. Other studies also documented non-selective activities of this drug in vivo . These findings severely h er data interpretation regarding C3aR when using this compound. Unfortunately, given the dearth of C3aR inhibitors, SB290157 still remains widely used to explore C3aR biology ( publications to date). Given these issues, in the present study we aimed to further explore SB290157’s pharmacological selectivity by screening the drug against three human anaphylatoxin receptors, C3aR, C5aR1 and C5aR2, using transfected cells. We first confirmed that SB290157 acts as a potent agonist at human C3aR. We also identified that SB290157 exerts partial agonist activity at C5aR2 by mediating β-arrestin recruitment at higher compound doses. Notably, SB290157’s activity at C5aR2 was more potent and efficacious than the current ‘lead’ C5aR2 agonist P32. Notwithstanding this, SB290157 showed inhibitory effect on C3a-mediated signalling in primary human macrophages. Our results therefore provide even more caution against using SB290157 as a research tool to explore C3aR function. Given the reported immunomodulatory and anti-inflammatory activities of C3aR and C5aR2 agonism, any function observed with SB290157 could be due to these off target activities.

Success in Navigating Hurdles to Oral Delivery of a Bioactive Peptide Complement Antagonist through Use of Nanoparticles to Increase Bioavailability and In Vivo Efficacy

Publisher: Wiley

Date: 09-2022

DOI: 10.1002/ADTP.202200109

Abstract: Substantial preclinical data have validated cyclic hexapeptide complement C5a receptor 1 antagonists (C5aRAs) that target immune cells, as novel therapies for a range of inflammatory diseases that currently have limited effective treatment options. However, like most small‐molecule peptides, their poor oral bioavailability and short circulation half‐life are major hurdles that have limited their clinical translation. Here, a single emulsion technique is employed to produce poly(lactic‐ co ‐glycolic) acid nanoparticles (NPs) with exceptionally high peptide C5aRA (PMX205) loading efficiency (over 50%). Strikingly, the PMX205‐NPs not only facilitate prolonged release of the encapsulated PMX205 but also dramatically increase its oral bioavailability (from ≈25% to ≈50%), and therapeutic potential (≈95% inhibition of C5a induces neutrophilia in mice and maintenance of neuroprotective barrier integrity). The enhanced in vivo pharmacological activity of PMX205 in the form of NPs opens an exciting opportunity for the clinical application of peptide C5aRAs and possibly other therapeutic peptides.

Neuroinflammation in Huntington’s Disease

Publisher: Springer US

Date: 16-10-2021

DOI: 10.1007/978-1-0716-1712-0_9

Significance of serum and hepatic markers of hepatitis B viral infection in HBsAg‐positive and HBsAg‐negative chronic active hepatitis

Publisher: Ovid Technologies (Wolters Kluwer Health)

Date: 1985

DOI: 10.1002/HEP.1840050112

Abstract: The correlation between serum and hepatic markers of hepatitis B virus (HBV) has been studied in 70 subjects with chronic active hepatitis of whom 18 were HBsAg+ and 52 were HBsAg-. In HBsAg+ subjects, sera were tested for HBeAg/anti-HBe status and for HBV DNA sequences using a DNA dot hybridization technique. Anti-HBs and anti-HBc were measured in serum in the HBsAg- group. Immunoperoxidase staining was used to detect HBsAg, HBcAg and delta antigen in liver tissue. Of the 18 HBsAg+ patients, 13 were HBeAg+ and 5 were anti-HBe+. A good correlation was shown between HBeAg and HBV DNA in serum and HBcAg expression in liver tissue. Neither HBV DNA in serum nor HBcAg in liver tissue was detected in any of the anti-HBe+ patients. HBsAg and/or HBcAg were detected in liver tissue in 17 of 18 HBsAg+ subjects (95%). However, neither HBsAg nor HBcAg were detected in liver tissue in 52 HBsAg- patients. This group included 11 patients with antibody markers in serum of past HBV infection. Thus, in contrast to previous studies, a good correlation was demonstrated between the serum and hepatic markers of viral replication, and no evidence was obtained to implicate the HBV as an etiological agent in HBsAg- chronic active hepatitis.

Evaluation of VIDAS® Immuno-Concentration Salmonella Assay Plus Selective Plate Method (Hektoen Enteric, Bismuth Sulfite, Salmonella Identification) for Detection of Salmonella in Selected Foods: Coll

Publisher: Oxford University Press (OUP)

Date: 05-2002

DOI: 10.1093/JAOAC/85.3.576

Abstract: The VIDAS Immuno-concentration Salmonella (ICS) plus selective plate method (Hektoen enteric, bismuth sulfite, Salmonella identification) method for the detection of Salmonella was compared to the Bacteriological Analytical Manual (BAM)/AOAC culture method in a collaborative study. Thirty-two laboratories participated in the evaluation. Each laboratory tested one or more of the 6 test products: milk chocolate, nonfat dry milk, dried whole egg, soy flour, ground black pepper, and ground raw turkey. The 2 methods were in agreement for 1283 of the 1440 test s les. Of the 157 test s les not in agreement, 82 were VIDAS ICS plus selective plate-positive and BAM/AOAC-negative, and 75 were VIDAS ICS plus selective plate-negative and BAM/AOAC-positive.

Development of Synthetic Human and Mouse C5a: Application to Binding and Functional Assays in Vitro and in Vivo

Publisher: American Chemical Society (ACS)

Date: 17-11-2021

DOI: 10.1021/ACSPTSCI.1C00199

Thrombin Differentially Modulates the Acute Inflammatory Response to Escherichia coli and Staphylococcus aureus in Human Whole Blood

Publisher: The American Association of Immunologists

Date: 15-06-2022

DOI: 10.4049/JIMMUNOL.2101033

Abstract: Thrombin plays a central role in thromboinflammatory responses, but its activity is blocked in the common ex vivo human whole blood models, making an ex vivo study of thrombin effects on thromboinflammatory responses unfeasible. In this study, we exploited the anticoagulant peptide Gly-Pro-Arg-Pro (GPRP) that blocks fibrin polymerization to study the effects of thrombin on acute inflammation in response to Escherichia coli and Staphylococcus aureus. Human blood was anticoagulated with either GPRP or the thrombin inhibitor lepirudin and incubated with either E. coli or S. aureus for up to 4 h at 37°C. In GPRP-anticoagulated blood, there were spontaneous elevations in thrombin levels and platelet activation, which further increased in the presence of bacteria. Complement activation and the expression of activation markers on monocytes and granulocytes increased to the same extent in both blood models in response to bacteria. Most cytokines were not elevated in response to thrombin alone, but thrombin presence substantially and heterogeneously modulated several cytokines that increased in response to bacterial incubations. Bacterial-induced releases of IL-8, MIP-1α, and MIP-1β were potentiated in the thrombin-active GPRP model, whereas the levels of IP-10, TNF, IL-6, and IL-1β were elevated in the thrombin-inactive lepirudin model. Complement C5-blockade, combined with CD14 inhibition, reduced the overall cytokine release significantly, both in thrombin-active and thrombin-inactive models. Our data support that thrombin itself marginally induces leukocyte-dependent cytokine release in this isolated human whole blood but is a significant modulator of bacteria-induced inflammation by a differential effect on cytokine patterns.

Partial ligand-receptor engagement yields functional bias at the human complement receptor, C5aR1

Publisher: Elsevier BV

Date: 06-2019

DOI: 10.1074/JBC.RA119.007485

Development of a novel angiotensin converting enzyme 2 stimulator with broad implications in SARS-CoV2 infection and type 1 diabetes

Publisher: Research Square Platform LLC

Date: 05-04-2023

DOI: 10.21203/RS.3.RS-2642181/V1

Abstract: Angiotensin-converting enzyme 2 (ACE2) is protective in cardiovascular disease, lung injury and diabetes yet paradoxically underlies our susceptibility to SARs-CoV2 infection and the fatal heart and lung disease it can induce. Furthermore, diabetic patients have chronic, systemic inflammation and altered ACE2 expression resulting in increased risk of severe COVID-19 and the associated mortality. A drug that could increase ACE2 activity and inhibit cellular uptake of severe acute respiratory syndrome coronavirus 2 (SARs-CoV2), thus decrease infection, would be of high relevance to cardiovascular disease, diabetes and SARs-CoV2 infection. While the need for such a drug lead was highlighted over a decade ago receiving over 600 citations, 1 to date, no such drugs are available. 2 Here, we report the development of a novel ACE2 stimulator, designated ‘2A’(international PCT filed), which is a 10 amino acid peptide derived from a snake venom, and demonstrate its in vitro and in vivo efficacy against SARs-CoV2 infection and associated lung inflammation. Peptide 2A also provides remarkable protection against glycaemic dysregulation, weight loss and disease severity in a mouse model of type 1 diabetes. No untoward effects of 2A were observed in these pre-clinical models suggesting its strong clinical translation potential.

Neutrophil Conversion to a Tumor-Killing Phenotype Underpins Effective Microbial Therapy

Publisher: American Association for Cancer Research (AACR)

Date: 14-02-2023

DOI: 10.1158/0008-5472.CAN-21-4025

Abstract: Intratumoral injection of microbial bioparticles stimulates neutrophil antitumor functions, suggesting pathways for optimizing efficacy of microbial therapies and paving the way for their broader utilization in the clinic.

C5aR1 regulates T follicular helper differentiation and chronic graft-versus-host disease bronchiolitis obliterans

Publisher: American Society for Clinical Investigation

Date: 20-12-2018

DOI: 10.1172/JCI.INSIGHT.124646

Salmonella in Selected Foods by VIDAS® Immuno-Concentration Salmonella Plus Selective Plate Method (Hektoen Enteric, Xylose Lysine Desoxycholate, Bismuth Sulfite): Collaborative Study

Publisher: Oxford University Press (OUP)

Date: 05-2002

DOI: 10.1093/JAOAC/85.3.593

Abstract: The VIDAS Immuno-concentration Salmonella (ICS) plus selective plate method (Hektoen enteric, xylose lysine desoxycholate, bismuth sulfite) method for the detection of Salmonella was compared to the Bacteriological Analytical Manual (BAM)/AOAC culture method in a collaborative study. Thirty-two laboratories participated in the evaluation. Each laboratory tested one or more of the 6 test products: milk chocolate, nonfat dry milk, dried whole egg, soy flour, ground black pepper, and ground raw turkey. The 2 methods were in agreement for 1297 of the 1455 s les. Of the 158 s les not in agreement, 82 were VIDAS ICS plus selective plate-positive and BAM/AOAC-negative, and 76 were VIDAS ICS plus selective plate-negative and BAM/AOAC-positive.

Increased expression of C5a receptor (CD88) mRNA in canine mammary tumors

Publisher: Elsevier BV

Date: 2011

DOI: 10.1016/J.VETIMM.2010.08.005

Abstract: Mammary tumors are among the most common neoplastic conditions in dogs, and there is evidence that inflammation plays a role in the development of some tumor types in dogs. The complement system is a major participant in the inflammatory process and the complement activation component, C5a, is a potent inflammatory peptide. This study investigated the mRNA expression of the major receptor for C5a (C5aR CD88) in histopathological s les of canine mammary tumors by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) using canine-specific primers for CD88. A total of seven canine mammary tumors (four malignant carcinomas, two benign mixed mammary tumors, and one myoepithelioma) and eight normal mammary glands were analysed. All the tumor s les expressed low levels of CD88 mRNA, while none of the normal mammary tissues showed any detectable expression. These preliminary results suggest that C5a-CD88 interaction may play a contributory role in the inflammatory response associated with mammary tumor development in dogs. Further studies investigating the mechanisms behind complement activation and C5a receptor expression in canine mammary tumors are warranted.

Tay-Sachs disease preconception screening in Australia: Self-knowledge of being an Ashkenazi Jew predicts carrier state better than does ancestral origin, although there is an increased risk for c.1421+1G>C mutation in individuals with South African heritage

Publisher: Springer Science and Business Media LLC

Date: 15-07-2011

DOI: 10.1007/S12687-011-0057-X

Benchmarking in pathology: Development of an activity-based costing model

Publisher: Elsevier BV

Date: 12-2012

DOI: 10.1097/PAT.0B013E32835A9EC4

C5a Receptor Signaling Prevents Folate Deficiency–Induced Neural Tube Defects in Mice

Publisher: The American Association of Immunologists

Date: 04-2013

DOI: 10.4049/JIMMUNOL.1203072

Abstract: The complement system is involved in a range of erse developmental processes, including cell survival, growth, differentiation, and regeneration. However, little is known about the role of complement in embryogenesis. In this study, we demonstrate a novel role for the canonical complement 5a receptor (C5aR) in the development of the mammalian neural tube under conditions of maternal dietary folic acid deficiency. Specifically, we found C5aR and C5 to be expressed throughout the period of neurulation in wild-type mice and localized the expression to the cephalic regions of the developing neural tube. C5aR was also found to be expressed in the neuroepithelium of early human embryos. Ablation of the C5ar1 gene or the administration of a specific C5aR peptide antagonist to folic acid–deficient pregnant mice resulted in a high prevalence of severe anterior neural tube defect-associated congenital malformations. These findings provide a new and compelling insight into the role of the complement system during mammalian embryonic development.

Suppl video 1 from Neutrophil Conversion to a Tumor-Killing Phenotype Underpins Effective Microbial Therapy

Publisher: American Association for Cancer Research (AACR)

Date: 14-04-2023

DOI: 10.1158/0008-5472.22633202

Abstract: Neutrophil migration before and after microbial bioparticle treatment.

Discovery of functionally selective C5aR2 ligands: Novel modulators of C5a signalling

Publisher: Wiley

Date: 17-05-2016

DOI: 10.1038/ICB.2016.43

Abstract: The complement cascade is comprised of a highly sophisticated network of innate immune proteins that are activated in response to invading pathogens or tissue injury. The complement activation peptide, C5a, binds two seven transmembrane receptors, namely the C5a receptor 1 (C5aR1) and C5a receptor 2 (C5aR2, or C5L2). C5aR2 is a non-G-protein-signalling receptor whose biological role remains controversial. Some of this controversy arises owing to the lack of selective ligands for C5aR2. In this study, a library of 61 peptides based on the C-terminus of C5a was assayed for the ability to selectively modulate C5aR2 function. Two ligands (P32 and P59) were identified as functionally selective C5aR2 ligands, exhibiting selective recruitment of β-arrestin 2 via C5aR2, partial inhibition of C5a-induced ERK1/2 activation and lipopolysaccharide-stimulated interleukin-6 release from human monocyte-derived macrophages. Importantly, neither ligand could induce ERK1/2 activation or inhibit C5a-induced ERK1/2 activation via C5aR1 directly. Finally, P32 inhibited C5a-mediated neutrophil mobilisation in wild-type, but not C5aR2(-/-) mice. These functionally selective ligands for C5aR2 are novel tools that can selectively modulate C5a activity in vitro and in vivo, and thus will be valuable tools to interrogate C5aR2 function.

Development of a superior strategy for computer-assisted nucleotide sequence analysis

Publisher: Oxford University Press (OUP)

Date: 1986

DOI: 10.1093/NAR/14.1.47

Abstract: A new strategy for high-resolution nucleotide sequence analysis has been developed. The strategy involves an exhaustive tree-searching algorithm which examines all possible combinations of short regions of sequence alignments, followed by culling of unsuitable sequence relationships. The new algorithm can detect sequence homologies invisible to existing algorithms, and is capable of detecting all possible sequence relationships.

Pathophysiology, treatment, and animal and cellular models of human ischemic stroke

Publisher: Springer Science and Business Media LLC

Date: 25-01-2011

DOI: 10.1186/1750-1326-6-11

Abstract: Stroke is the world's second leading cause of mortality, with a high incidence of severe morbidity in surviving victims. There are currently relatively few treatment options available to minimize tissue death following a stroke. As such, there is a pressing need to explore, at a molecular, cellular, tissue, and whole body level, the mechanisms leading to damage and death of CNS tissue following an ischemic brain event. This review explores the etiology and pathogenesis of ischemic stroke, and provides a general model of such. The pathophysiology of cerebral ischemic injury is explained, and experimental animal models of global and focal ischemic stroke, and in vitro cellular stroke models, are described in detail along with experimental strategies to analyze the injuries. In particular, the technical aspects of these stroke models are assessed and critically evaluated, along with detailed descriptions of the current best-practice murine models of ischemic stroke. Finally, we review preclinical studies using different strategies in experimental models, followed by an evaluation of results of recent, and failed attempts of neuroprotection in human clinical trials. We also explore new and emerging approaches for the prevention and treatment of stroke. In this regard, we note that single-target drug therapies for stroke therapy, have thus far universally failed in clinical trials. The need to investigate new targets for stroke treatments, which have pleiotropic therapeutic effects in the brain, is explored as an alternate strategy, and some such possible targets are elaborated. Developing therapeutic treatments for ischemic stroke is an intrinsically difficult endeavour. The heterogeneity of the causes, the anatomical complexity of the brain, and the practicalities of the victim receiving both timely and effective treatment, conspire against developing effective drug therapies. This should in no way be a disincentive to research, but instead, a clarion call to intensify efforts to ameliorate suffering and death from this common health catastrophe. This review aims to summarize both the present experimental and clinical state-of-the art, and to guide future research directions.

Complement System Inhibition Modulates the Inflammation Induced by the Venom of Premolis semirufa, an Amazon Rainforest Moth Caterpillar

Publisher: MDPI AG

Date: 11-2022

DOI: 10.3390/IJMS232113333

Abstract: The caterpillar of the Premolis semirufa moth, commonly called Pararama, is found in the Brazilian Amazon region. Contact with the hairs can cause a chronic inflammatory reaction, termed “pararamosis”. To date, there is still no specific treatment for pararamosis. In this study, we used a whole human blood model to evaluate the involvement of the complement in the proinflammatory effects of P. semirufa hair extract, as well as the anti-inflammatory potential of complement inhibitors in this process. After treatment of blood s les with the P. semirufa hair extract, there was a significant increase in the generation of soluble terminal complement complex (sTCC) and anaphylatoxins (C3a, C4a, and C5a), as well as the production of the cytokines TNF-α and IL-17 and the chemokines IL-8, RANTES, MIG, MCP-1, and IP-10. The inhibition of C3 with compstatin significantly decreased IL-17, IL-8, RANTES, and MCP-1 production. However, the use of the C5aR1 antagonist PMX205 promoted a reduction in the production of IL-8 and RANTES. Moreover, compstatin decreased CD11b, C5aR1, and TLR2 expression induced by P. semirufa hair extract in granulocytes and CD11b, TLR4, and TLR2 in monocytes. When we incubated vascular endothelial cells with extract-treated human plasma, there was an increase in IL-8 and MCP-1 production, and compstatin was able to decrease the production of these chemokines. C5aR1 antagonism also decreased the production of MCP-1 in endothelial cells. Thus, these results indicate that the extract of the Pararama bristles activates the complement system and that this action contributes to the production of cytokines and chemokines, modulation of the expression of surface markers in leukocytes, and activation of endothelial cells.

Diagnosis of diabetes in anaemias and haemoglobinopathies: Salutary lessons for improved reporting and patient empowerment

Publisher: Elsevier BV

Date: 06-2014

DOI: 10.1097/PAT.0000000000000103

Complement inhibitors selectively attenuate injury following administration of cobra venom factor to rats

Publisher: Elsevier BV

Date: 08-2006

DOI: 10.1016/J.INTIMP.2006.03.002

Abstract: Systemic activation of complement is a pathophysiological response common to severe disturbances such as hemorrhagic shock, major burn injury and sepsis. Intravenous infusion of cobra venom factor (CVF) has been used as an animal model of acute respiratory distress syndrome (ARDS), and reliably and selectively induces rapid intravascular activation of the complement system, leading to acute organ damage. In the present study, we have used different complement inhibitors to investigate the roles of complement products in CVF-induced responses in the rat. Rats were treated with either a C5a receptor antagonist (C5aRA, AcF-[OP(d-Cha)WR], 1 mg/kg i.v. or 10 mg/kg p.o.), a C3a receptor antagonist (C3aRA, N(2)-[(2,2-diphenylethoxy)acetyl]-l-arginine, 0.1 mg/kg i.v.) or a convertase inhibitor, rosmarinic acid (RMA, 10 mg/kg i.v.), prior to CVF-induced complement challenge. Intravenous CVF resulted in hallmark events evident in the development of ARDS, including systemic neutropenia followed by neutrophil migration to the lung and bronchoalveolar vascular leakage, blood pressure alterations, and an increase in TNFalpha levels in both serum and bronchoalveolar lavage fluid. These hemodynamic changes were differentially inhibited by antagonism of C5a receptors, C3a receptors or by inhibition of the entire complement cascade using RMA. This evidence strongly implicates complement factors in the development of lung injury associated with systemic complement activation and identifies complement inhibition as a potential therapeutic target for acute syndromes such as ARDS and other severe systemic shock states mediated by activation of complement.

Inhibiting the C5–C5a receptor axis

Publisher: Elsevier BV

Date: 08-2011

DOI: 10.1016/J.MOLIMM.2011.04.014

Abstract: Activation of the complement system is a major pathogenic event that drives various inflammatory responses in numerous diseases. All pathways of complement activation lead to cleavage of the C5 molecule generating the anaphylatoxin C5a and, C5b that subsequently forms the terminal complement complex (C5b-9). C5a exerts a predominant pro-inflammatory activity through interactions with the classical G-protein coupled receptor C5aR (CD88) as well as with the non-G protein coupled receptor C5L2 (GPR77), expressed on various immune and non-immune cells. C5b-9 causes cytolysis through the formation of the membrane attack complex (MAC), and sub-lytic MAC and soluble C5b-9 also possess a multitude of non-cytolytic immune functions. These two complement effectors, C5a and C5b-9, generated from C5 cleavage, are key components of the complement system responsible for propagating and/or initiating pathology in different diseases, including paroxysmal nocturnal hemoglobinuria, rheumatoid arthritis, ischemia-reperfusion injuries and neurodegenerative diseases. Thus, the C5-C5a receptor axis represents an attractive target for drug development. This review provides a comprehensive analysis of different methods of inhibiting the generation of C5a and C5b-9 as well as the signalling cascade of C5a via its receptors. These include the inhibition of C5 cleavage through targeting of C5 convertases or via the C5 molecule itself, as well as blocking the activity of C5a by neutralizing antibodies and pharmacological inhibitors, or by targeting C5a receptors per se. Ex les of drugs and naturally occurring compounds used are discussed in relation to disease models and clinical trials. To date, only one such compound has thus far made it to clinical medicine: the anti-C5 antibody eculizumab, for treating paroxysmal nocturnal hemoglobinuria. However, a number of drug candidates are rapidly emerging that are currently in early-phase clinical trials. The C5-C5a axis as a target for drug development is highly promising for the treatment of currently intractable major human diseases.

Crosstalk between TGF‐β1 and complement activation augments epithelial injury in pulmonary fibrosis

Publisher: Wiley

Date: 23-06-2014

DOI: 10.1096/FJ.13-247650

Antiarthritic activity of an orally active C5a receptor antagonist against antigen-induced monarticular arthritis in the rat

Publisher: Wiley

Date: 09-2002

DOI: 10.1002/ART.10449

Abstract: To determine if the new, orally active C5a receptor antagonist, the cyclic peptide AcF-[OPdChaWR], reduces the severity of pathology in a rat model of immune-mediated monarticular arthritis. Arthritis was induced in the right knee of previously sensitized rats by the intraarticular injection of methylated bovine serum albumin. Rats were examined for either 14 days or 28 days, or for 49 days following a second antigen challenge at 28 days. The C5a antagonist (1 or 3 mg/kg/day) and/or ibuprofen (30 mg/kg/day) were administered orally on a daily basis either before or after arthritis induction. Rats receiving AcF-[OPdChaWR] had significant reductions in right knee swelling, gait disturbance, lavaged joint cell numbers, and right knee histopathology, as well as in serum levels of tumor necrosis factor alpha (TNFalpha) and intraarticular levels of interleukin-6 and TNFalpha on day 14. In the 14- and 28-day studies, ibuprofen resulted in a similar reduction in gait abnormalities and intraarticular inflammatory cells compared with the C5a antagonist, but was less effective in reducing knee swelling over the course of the study and had no effect on knee histopathology. Combination therapy with AcF-[OPdChaWR] and ibuprofen resulted in no greater efficacy than with the C5a antagonist alone. Rats injected twice with the antigen in the 49-day study displayed the most severe histopathology and this, as well as knee swelling and gait abnormalities, was significantly reduced by repeated treatment with the C5a antagonist. An agent that inhibits the action of C5a in this model significantly reduced joint pathology, while ibuprofen was not effective. C5a antagonists could therefore have broader therapeutic benefits than nonsteroidal antiinflammatory drugs as antiarthritic agents for rheumatoid arthritis.

C5a alters blood–brain barrier integrity in a human in vitro model of systemic lupus erythematosus

Publisher: Wiley

Date: 15-07-2015

DOI: 10.1111/IMM.12489

Protective effect of a new C5a receptor antagonist against ischemia-reperfusion injury in the rat small intestine

Publisher: Elsevier BV

Date: 04-2002

DOI: 10.1006/JSRE.2002.6369

Therapeutic activity of C5a receptor antagonists in a rat model of neurodegeneration

Publisher: Wiley

Date: 07-2006

DOI: 10.1096/FJ.05-5814COM

Abstract: The complement system is thought to be involved in the pathogenesis of numerous neurological diseases, although its precise role remains controversial. In this study we used orally active C5a receptor antagonists (PMX53 and PMX205) developed in our laboratories in a rat model of 3-nitropropionic acid (3-NP) -induced Huntington's disease. Administration of the C5a antagonists (10 mg/kg/day, oral) either 48 h pre- or 48 h post-toxin significantly reduced body weight loss, anorexia, and behavioral and motor deficits associated with 3-NP intoxication. Striatal lesion size, apoptosis, neutrophil infiltration, and hemorrhage were also significantly reduced in C5a antagonist-treated rats. Immunohistochemical analysis demonstrated marked deposition of C3 and C9, and up-regulation of C5a receptors on neuronal cells at the time of lesion formation. Inhibition of prostaglandins or TNF-alpha with ibuprofen or infliximab had no effect in this model. The C5a antagonists did not affect 3-NP-induced cell death when added directly to rat striatal neuronal cultures, indicating a secondary mechanism of action in vivo. Our findings demonstrate for the first time that complement activation in the brain, particularly C5a, is a key event in the pathogenesis of this disease model, and suggest a future role for inhibitors of C5a in the treatment of neurodegenerative diseases.

T Cell Expression of C5a Receptor 2 Augments Murine Regulatory T Cell (TREG) Generation and TREG-Dependent Cardiac Allograft Survival

Publisher: The American Association of Immunologists

Date: 15-03-2018

DOI: 10.4049/JIMMUNOL.1701638

Abstract: C5aR2 (C5L2/gp77) is a seven-transmembrane spanning receptor that binds to C5a but lacks motifs essential for G protein coupling and associated signal transduction. C5aR2 is expressed on immune cells, modulates various inflammatory diseases in mice, and has been shown to facilitate murine and human regulatory T cell (TREG) generation in vitro. Whether and how C5aR2 impacts in vivo TREG generation and pathogenic T cell–dependent disease models have not been established. In this article, we show that murine T cells express and upregulate C5aR2 during induced TREG (iTREG) generation and that the absence of T cell–expressed C5aR2 limits in vivo iTREG generation following adoptive transfer of naive CD4+ T cells into Rag1−/− recipients. Using newly generated C5aR2-transgenic mice, we show that overexpression of C5aR2 in naive CD4+ T cells augments in vivo iTREG generation. In a model of TREG-dependent cardiac allograft survival, recipient C5aR2 deficiency accelerates graft rejection associated with lower TREG/effector T cell ratios, whereas overexpression of C5aR2 in immune cells prolongs graft survival associated with an increase in TREG/effector T cell ratios. T cell–expressed C5aR2 modulates TREG induction without altering effector T cell proliferation or cytokine production. Distinct from reported findings in neutrophils and macrophages, TREG-expressed C5aR2 does not interact with β-arrestin or inhibit ERK1/2 signaling. Rather, cumulative evidence supports the conclusion that C5aR2 limits C5aR1-initiated signals known to inhibit TREG induction. Together, the data expand the role of C5aR2 in adaptive immunity by providing in vivo evidence that T cell–expressed C5aR2 physiologically modulates iTREG generation and iTREG-dependent allograft survival.

Making sense of a haemolysis monitoring and reporting system: a nationwide longitudinal multimethod study of 68 Australian laboratory participant organisations

Publisher: Walter de Gruyter GmbH

Date: 15-09-2018

DOI: 10.1515/CCLM-2017-0056

Abstract: The key incident monitoring and management systems (KIMMS) quality assurance program monitors incidents in the pre- and postanalytical phases of testing in medical laboratories. Haemolysed specimens have been found to be the most frequent preanalytical error and have major implications for patient care. The aims of this study were to assess the suitability of KIMMS for quality reporting of haemolysis and to devise a meaningful method for reporting and monitoring haemolysis. A structured survey of 68 Australian KIMMS laboratory participant organisations was undertaken. Quarterly haemolysis reports (2011–2014) were analysed. Among 110 million accessions reported, haemolysis rates varied according to the reporting methods that participants used for assigning accessions (16% of participants reported haemolysis by specimen and 83% reported by episode) and counting haemolysis rejections (61% by specimen, 35% by episode and 3% by test). More than half of the participants (56%) assigned accessions by episode and counted rejections by specimen. For this group, the average haemolysis rate per 100,000 episodes was 177 rejected specimens with the average rate varying from 100 to 233 over time. The majority of participants (91%) determined rejections using the haemolysis index. Two thirds of participants (66%) recorded the haemolysis manually in laboratory information systems. KIMMS maintains the largest longitudinal haemolysis database in the world. However, as a means of advancing improvements in the quality of the preanalytical laboratory process, there is a need to standardise reporting methods to enable robust comparison of haemolysis rejection rates across participant laboratories.

Complement factor C5a as mast cell activator mediates vascular remodelling in vein graft disease

Publisher: Oxford University Press (OUP)

Date: 14-10-2012

DOI: 10.1093/CVR/CVS312

Abstract: Failure of vein graft conduits due to vein graft thickening, accelerated atherosclerosis, and subsequent plaque rupture is applicable to 50% of all vein grafts within 10 years. New potential therapeutic targets to treat vein graft disease may be found in components of the innate immune system, such as mast cells and complement factors, which are known to be involved in atherosclerosis and plaque destabilization. Interestingly, mast cells can be activated by complement factor C5a and, therefore, a direct role for C5a-mediated mast cell activation in vein graft disease is anticipated. We hypothesize that C5a-mediated mast cell activation is involved in the development and destabilization of vein graft lesions. Mast cells accumulated in time in murine vein graft lesions, and C5a and C5a-receptor (CD88) expression was up-regulated during vein graft disease in apolipoprotein E-deficient mice. Mast cell activation with dinitrophenyl resulted in a profound increase in vein graft thickening and in the number of plaque disruptions. C5a application enhanced vein graft lesion formation, while treatment with a C5a-receptor antagonist resulted in decreased vein graft disease. C5a most likely exerts its function via mast cell activation since the mast cell inhibitor cromolyn totally blocked C5a-enhanced vein graft disease. These data provide evidence that complement factor C5a-induced mast cell activation is highly involved in vein graft disease, which identifies new targets to prevent vein graft disease.

Complement C5a Receptor 1 Exacerbates the Pathophysiology ofN. meningitidisSepsis and Is a Potential Target for Disease Treatment

Publisher: American Society for Microbiology

Date: 07-03-2018

DOI: 10.1128/MBIO.01755-17

Abstract: Sepsis caused by Neisseria meningitidis (meningococcus) is a rapidly progressing, life-threatening disease. Because its initial symptoms are rather unspecific, medical attention is often sought too late, i.e., when the systemic inflammatory response is already unleashed. This in turn limits the success of antibiotic treatment. The complement system is generally accepted as the most important innate immune determinant against invasive meningococcal disease since it protects the host through the bactericidal membrane attack complex. However, complement activation concomitantly liberates the C5a peptide, and it remains unclear whether this potent anaphylatoxin contributes to protection and/or drives the rapidly progressing immunopathogenesis associated with meningococcal disease. Here, we dissected the specific contribution of C5a receptor 1 (C5aR1), the canonical receptor for C5a, using a mouse model of meningococcal sepsis. Mice lacking C3 or C5 displayed susceptibility that was enhanced by ,000-fold or 100-fold, respectively, consistent with the contribution of these components to protection. In clear contrast, C5ar1 −/− mice resisted invasive meningococcal infection and cleared N. meningitidis more rapidly than wild-type (WT) animals. This favorable outcome stemmed from an ameliorated inflammatory cytokine response to N. meningitidis in C5ar1 −/− mice in both in vivo and ex vivo whole-blood infections. In addition, inhibition of C5aR1 signaling without interference with the complement bactericidal activity reduced the inflammatory response also in human whole blood. Enticingly, pharmacologic C5aR1 blockade enhanced mouse survival and lowered meningococcal burden even when the treatment was administered after sepsis induction. Together, our findings demonstrate that C5aR1 drives the pathophysiology associated with meningococcal sepsis and provides a promising target for adjunctive therapy. IMPORTANCE The devastating consequences of N. meningitidis sepsis arise due to the rapidly arising and self-propagating inflammatory response that mobilizes antibacterial defenses but also drives the immunopathology associated with meningococcemia. The complement cascade provides innate broad-spectrum protection against infection by directly damaging the envelope of pathogenic microbes through the membrane attack complex and triggers an inflammatory response via the C5a peptide and its receptor C5aR1 aimed at mobilizing cellular effectors of immunity. Here, we consider the potential of separating the bactericidal activities of the complement cascade from its immune activating function to improve outcome of N. meningitidis sepsis. Our findings demonstrate that the specific genetic or pharmacological disruption of C5aR1 rapidly ameliorates disease by suppressing the pathogenic inflammatory response and, surprisingly, allows faster clearance of the bacterial infection. This outcome provides a clear demonstration of the therapeutic benefit of the use of C5aR1-specific inhibitors to improve the outcome of invasive meningococcal disease.

Absence of the c5a receptor c5ar2 worsens ischemic tissue injury by increasing c5ar1-mediated neutrophil infiltration

Publisher: The American Association of Immunologists

Date: 15-11-2020

DOI: 10.4049/JIMMUNOL.2000778

Abstract: Neutrophil infiltration to ischemic tissues following reperfusion worsens injury. A key driver of neutrophil recruitment and activation is the complement factor C5a, which signals through two receptors, C5aR1 and C5aR2. In this study, we used a neutrophil-dependent mouse model of intestinal ischemia-reperfusion (IR) injury to investigate the underexplored role of C5aR2 in neutrophil mobilization, recruitment, and disease outcomes. We show that intestinal IR induces rapid neutrophil mobilization along with a concomitant reduction in plasma C5a levels that is driven by both C5aR1 and C5aR2. Intestinal IR in C5aR2−/− mice led to worsened intestinal damage and increased neutrophil infiltration. Inhibition of C5aR1 signaling in C5aR2−/− mice with PMX53 prevented neutrophil accumulation and reduced IR pathology, suggesting a key requirement for enhanced neutrophil C5aR1 activation in the absence of C5aR2 signaling. Interestingly, C5aR2 deficiency also reduced circulating neutrophil numbers after IR, as well as following G-CSF–mediated bone marrow mobilization, which was independent of C5aR1, demonstrating that C5aR2 has unique and distinct functions from C5aR1 in neutrophil egress. Despite enhanced tissue injury in C5aR2−/− IR mice, there were significant reductions in intestinal proinflammatory cytokines, highlighting complicated dual protective athogenic roles for C5aR2 in pathophysiology. Collectively, we show that C5aR2 is protective in intestinal IR by inhibiting C5aR1-mediated neutrophil recruitment to the ischemic tissue. This is despite the potentially local pathogenic effects of C5aR2 in increasing intestinal proinflammatory cytokines and enhancing circulating neutrophil numbers in response to mobilizing signals. Our data therefore suggest that this balance between the dual pro- and anti-inflammatory roles of C5aR2 ultimately dictates disease outcomes.

A Small Molecule Angiotensin II Type 2 Receptor (AT₂R) Antagonist Produces Analgesia in a Rat Model of Neuropathic Pain by Inhibition of p38 Mitogen-Activated Protein Kinase (MAPK) and p44/

Publisher: Oxford University Press (OUP)

Date: 10-2013

DOI: 10.1111/PME.12157

Abstract: There is an unmet clinical need for novel analgesics for neuropathic pain. This study was designed to elucidate the mechanism through which EMA300, a small molecule antagonist of the angiotensin II type 2 receptor (AT₂R) with >1,000-fold selectivity over the angiotensin II type 1 receptor, produces analgesia in a rodent model of neuropathic pain. Groups of AT₂R knockout, hemizygotes, and wild-type mice with a chronic constriction injury (CCI) of the sciatic nerve received single intraperitoneal (i.p.) bolus doses of EMA300 (100 or 300 mg/kg), and analgesic efficacy was assessed. Groups of control, sham-operated, and CCI rats were euthanized and perfusion fixed. Lumbar dorsal root ganglia (DRGs) were removed for investigation of the mechanism through which EMA300 alleviates neuropathic pain. EMA300 analgesia was abolished in AT₂R knockout CCI mice with intermediate responses in the hemizygotes, affirming the AT₂R as the target mediating EMA300 analgesia. In CCI rats, DRG immunofluorescence (IF) levels for angiotensin II, the main endogenous ligand of the AT₂R, were increased ∼1.5-2.0-fold (P < 0.05) cf. sham-controls. Mean DRG IF levels for activated p38 (pp38) and activated p44 42 (pp44 p42) MAPK were also increased ∼1.5-2.0-fold (P < 0.05) cf. sham-controls. At the time of peak EMA300 analgesia in CCI rats, mean DRG levels of pp38 MAPK and pp44 p42 MAPK (but not angiotensin II) were reduced to match the respective levels in sham-controls. Augmented angiotensin II/AT₂R signaling in the DRGs of CCI rats is attenuated by EMA300 to block p38 MAPK and p44 42 MAPK activation, a mechanism with clinical validity for alleviating neuropathic pain.

Revisiting the role of the innate immune complement system in ALS

Publisher: Elsevier BV

Date: 07-2019

DOI: 10.1016/J.NBD.2019.03.003

Abstract: Amyotrophic lateral sclerosis (ALS) is a fatal and rapidly progressing motor neuron disease without effective treatment. Although the precise mechanisms leading to ALS are yet to be determined, there is now increasing evidence implicating components of the innate immune complement system in the onset and progression of its motor phenotypes. This review will survey the clinical and experimental evidence for the role of the complement system in driving neuroinflammation and contributing to ALS disease progression. Specifically, it will explore findings regarding the different complement activation pathways involved in ALS, with a focus on the terminal pathway. It will also examine potential future research directions for complement in ALS, highlighting the targeting of specific molecular components of the system.

Data from Neutrophil Conversion to a Tumor-Killing Phenotype Underpins Effective Microbial Therapy

Publisher: American Association for Cancer Research (AACR)

Date: 14-04-2023

DOI: 10.1158/0008-5472.C.6599657

Abstract: Abstract The inflammatory microenvironment of solid tumors creates a protumorigenic milieu that resembles chronic inflammation akin to a subverted wound healing response. Here, we investigated the effect of converting the tumor microenvironment from a chronically inflamed state to one of acute microbial inflammation by injecting microbial bioparticles directly into tumors. Intratumoral microbial bioparticle injection led to rapid and dramatic changes in the tumor immune composition, the most striking of which was a substantial increase in the presence of activated neutrophils. i In situ /i photoconversion and intravital microscopy indicated that tumor neutrophils transiently switched from sessile producers of VEGF to highly motile neutrophils that clustered to make neutrophil-rich domains in the tumor. The neutrophil clusters remodeled tumor tissue and repressed tumor growth. Single-cell transcriptional analysis of microbe-stimulated neutrophils showed a profound shift in gene expression towards heightened activation and antimicrobial effector function. Microbe-activated neutrophils also upregulated chemokines known to regulate neutrophil and CD8 sup + /sup T-cell recruitment. Microbial therapy also boosted CD8 sup + /sup T-cell function and enhanced the therapeutic benefit of checkpoint inhibitor therapy in tumor-bearing mice and provided protection in a model of tumor recurrence. These data indicate that one of the major effector mechanisms of microbial therapy is the conversion of tumor neutrophils from a wound healing to an acutely activated cytotoxic phenotype, highlighting a rationale for broader deployment of microbial therapy in the treatment of solid cancers. Significance: Intratumoral injection of microbial bioparticles stimulates neutrophil antitumor functions, suggesting pathways for optimizing efficacy of microbial therapies and paving the way for their broader utilization in the clinic. /

A potent and selective inhibitor of group IIa secretory phospholipase A(2) protects rats from TNBS-induced colitis

Publisher: Elsevier BV

Date: 05-2005

DOI: 10.1016/J.INTIMP.2005.01.003

Abstract: Secretory phospholipase A(2) (sPLA(2)) enzymes have been implicated in the pathogenesis of human inflammatory bowel disease (IBD). In this study we compared the efficacy of a potent, new and highly selective inhibitor of group IIa human sPLA(2) enzyme (5-(4-benzyloxyphenyl)-4S-(7-phenylheptanoylamino)-pentanoic acid sPLA(2)I), with that of sulfasalazine, in a rat model of trinitrobenzene sulfonic acid (TNBS)-induced colitis. Following a single oral dose of sPLA(2)I (5 mg/kg), pharmacoactive levels of drug were detected in the serum within 15 min and for up to 24 h by liquid chromatography mass spectrometry analysis. Rats treated with sPLA(2)I (5 mg/kg/day) prior to induction of colitis were significantly healthier than TNBS-alone rats, as shown by reduced mortality, improved food intake and increased body weight, and significantly reduced colon myeloperoxidase levels, edema, tumour necrosis factor-alpha levels, and colon macroscopic pathology scores after 8 days. Rats pretreated with sulfasalazine (100 mg/kg/day) also had reduced disease expression markers similar to the sPLA(2)I, but exhibited no improvement in colon edema. This study supports a role for the group IIa sPLA(2) enzyme in pathology associated with the TNBS rat model of IBD, and suggests a possible therapeutic application for selective inhibitors of group IIa sPLA(2) inhibitors in the treatment of IBD.

Autoantibodies against homocysteinylated protein in a mouse model of folate deficiency‐induced neural tube defects

Publisher: Wiley

Date: 22-02-2016

DOI: 10.1002/BDRA.23483

SARS-CoV-2 drives NLRP3 inflammasome activation in human microglia through spike protein

Publisher: Springer Science and Business Media LLC

Date: 11-2022

DOI: 10.1038/S41380-022-01831-0

Abstract: Coronavirus disease-2019 (COVID-19) is primarily a respiratory disease, however, an increasing number of reports indicate that SARS-CoV-2 infection can also cause severe neurological manifestations, including precipitating cases of probable Parkinson’s disease. As microglial NLRP3 inflammasome activation is a major driver of neurodegeneration, here we interrogated whether SARS-CoV-2 can promote microglial NLRP3 inflammasome activation. Using SARS-CoV-2 infection of transgenic mice expressing human angiotensin-converting enzyme 2 (hACE2) as a COVID-19 pre-clinical model, we established the presence of virus in the brain together with microglial activation and NLRP3 inflammasome upregulation in comparison to uninfected mice. Next, utilising a model of human monocyte-derived microglia, we identified that SARS-CoV-2 isolates can bind and enter human microglia in the absence of viral replication. This interaction of virus and microglia directly induced robust inflammasome activation, even in the absence of another priming signal. Mechanistically, we demonstrated that purified SARS-CoV-2 spike glycoprotein activated the NLRP3 inflammasome in LPS-primed microglia, in a ACE2-dependent manner. Spike protein also could prime the inflammasome in microglia through NF-κB signalling, allowing for activation through either ATP, nigericin or α-synuclein. Notably, SARS-CoV-2 and spike protein-mediated microglial inflammasome activation was significantly enhanced in the presence of α-synuclein fibrils and was entirely ablated by NLRP3-inhibition. Finally, we demonstrate SARS-CoV-2 infected hACE2 mice treated orally post-infection with the NLRP3 inhibitory drug MCC950, have significantly reduced microglial inflammasome activation, and increased survival in comparison with untreated SARS-CoV-2 infected mice. These results support a possible mechanism of microglial innate immune activation by SARS-CoV-2, which could explain the increased vulnerability to developing neurological symptoms akin to Parkinson’s disease in COVID-19 infected in iduals, and a potential therapeutic avenue for intervention.

Potent Cyclic Antagonists of the Complement C5a Receptor on Human Polymorphonuclear Leukocytes. Relationships between Structures and Activity

Publisher: American Society for Pharmacology & Experimental Therapeutics (ASPET)

Date: 25-03-2004

DOI: 10.1124/MOL.65.4.868

Optimizing the availability of 'stat' laboratory tests using Shewhart 'c' control charts

Publisher: SAGE Publications

Date: 03-2002

DOI: 10.1258/0004563021901892

Abstract: Background: We describe a general strategy for optimizing the availability of 'stat' out-of-hours laboratory tests to the particular clinical needs of health care institutions. Methods: We initially introduced a consensus menu of 'stat' tests and prospectively monitored for 5 years all additional requests for 'stat' clinical biochemistry tests in a metropolitan tertiary referral university teaching hospital. Laboratory staff triaged 'stat' requests, and clinical biochemistry consultants reviewed requests not already performed routinely. The frequency of these requests was monitored on a Shewhart 'c' control chart. A quality system certified to ISO 9001 was used to assure laboratory compliance with procedures. Various interventions were tested using the Shewhart 'c' control chart to monitor their effectiveness. Results: Matching the timing of analytical assays with the time of s le collection had no significant effect on the number of 'stat' requests. Implementation of a hospital-wide laboratory information system also had no significant effect on the number of 'stat' requests. The most effective strategy consisted of optimization of the test menu to match request patterns, combined with the introduction of a laboratory quality system. Conclusions: Within our institution, this strategy resulted in a sevenfold reduction in 'stat' requests, from one per 2200 specimens to fewer than one per 32 000 specimens.

Placental Lipases in Pregnancies Complicated by Gestational Diabetes Mellitus (GDM)

Publisher: Public Library of Science (PLoS)

Date: 12-08-2014

DOI: 10.1371/JOURNAL.PONE.0104826

Differential co-expression of α-actin genes within the human heart

Publisher: Elsevier BV

Date: 09-1986

DOI: 10.1016/S0022-2828(86)80013-X

Abstract: Human cardiac muscle has been studied to determine whether the ratio of cardiac alpha-actin to skeletal alpha-actin varies between the different chambers of the human heart taken from a single in idual. Using mRNA dot-blots, and DNA probes specific for the cardiac and skeletal alpha-actin isotypes, we have found that both cardiac and skeletal alpha-actin mRNAs are present and co-expressed throughout the human heart. The pattern of alpha-actin co-expression in the left and right ventricles and in the interventricular septum is approximately the same, with cardiac alpha-actin being the dominant isotype (approx. 80% of total). However, the left atrium has a different relative composition of the two actins, with an even higher level of cardiac alpha-actin expression (95% of total).

Community Genetics screening in a pandemic: solutions for pre-test education, informed consent, and specimen collection

Publisher: Springer Science and Business Media LLC

Date: 11-01-2023

DOI: 10.1038/S41431-022-01251-2

Abstract: A Community Genetics carrier screening program for the Jewish community has operated on-site in high schools in Sydney (Australia) for 25 years. During 2020, in response to the COVID-19 pandemic, government-mandated social-distancing, ‘lock-down’ public health orders, and laboratory supply-chain shortages prevented the usual operation and delivery of the annual testing program. We describe development of three responses to overcome these challenges: (1) pivoting to online education sufficient to ensure informed consent for both genetic and genomic testing (2) development of contactless telehealth with remote training and supervision for collecting genetic s les using buccal swabs and (3) a novel patient and specimen identification ‘GeneTrustee’ protocol enabling fully identified clinical-grade specimens to be collected and DNA extracted by a research laboratory while maintaining full participant confidentiality and privacy. These telehealth strategies for education, consent, specimen collection and s le processing enabled uninterrupted delivery and operation of complex genetic testing and screening programs even amid pandemic restrictions. These tools remain available for future operation and can be adapted to other programs.

Complement component 5 does not interfere with physiological hemostasis but is essential forEscherichia coli-induced coagulation accompanied by Toll-like receptor 4

Publisher: Oxford University Press (OUP)

Date: 19-12-2018

DOI: 10.1111/CEI.13240

Abstract: There is a close cross-talk between complement, Toll-like receptors (TLRs) and coagulation. The role of the central complement component 5 (C5) in physiological and pathophysiological hemostasis has not, however, been fully elucidated. This study examined the effects of C5 in normal hemostasis and in Escherichia coli-induced coagulation and tissue factor (TF) up-regulation. Fresh whole blood obtained from six healthy donors and one C5-deficient in idual (C5D) was anti-coagulated with the thrombin inhibitor lepirudin. Blood was incubated with or without E. coli in the presence of the C5 inhibitor eculizumab, a blocking anti-CD14 monoclonal antibody (anti-CD14) or the TLR-4 inhibitor eritoran. C5D blood was reconstituted with purified human C5. TF mRNA was measured by quantitative polymerase chain reaction (qPCR) and monocyte TF and CD11b surface expression by flow cytometry. Prothrombin fragment 1+2 (PTF1·2) in plasma and microparticles exposing TF (TF-MP) was measured by enzyme-linked immunosorbent assay (ELISA). Coagulation kinetics were analyzed by rotational thromboelastometry and platelet function by PFA-200. Normal blood with eculizumab as well as C5D blood with or without reconstitution with C5 displayed completely normal biochemical hemostatic patterns. In contrast, E. coli-induced TF mRNA and TF-MP were significantly reduced by C5 inhibition. C5 inhibition combined with anti-CD14 or eritoran completely inhibited the E. coli-induced monocyte TF, TF-MP and plasma PTF1·2. Addition of C5a alone did not induce TF expression on monocytes. In conclusion, C5 showed no impact on physiological hemostasis, but substantially contributed to E. coli-induced procoagulant events, which were abolished by the combined inhibition of C5 and CD14 or TLR-4.

Absence of Receptor for Advanced Glycation End Product (RAGE) Reduces Inflammation and Extends Survival in the hSOD1G93A Mouse Model of Amyotrophic Lateral Sclerosis

Publisher: Springer Science and Business Media LLC

Date: 16-07-2020

DOI: 10.1007/S12035-020-02019-9

The role of the ribosomal protein S19 C-terminus in Gi protein-dependent alternative activation of p38 MAP kinase via the C5a receptor in HMC-1 cells

Publisher: Springer Science and Business Media LLC

Date: 15-05-2010

DOI: 10.1007/S10495-010-0511-Y

Abstract: We have demonstrated that an alternative C5a receptor (C5aR) ligand, the homodimer of ribosomal protein S19 (RP S19), contains a unique C-terminus (I(134)-H(145)) that is distinct from the moieties involved in the C5a-C5aR interaction. To examine the role of I(134)-H(145) in the ligand-C5aR interaction, we connected this peptide to the C-terminus of C5a (C5a/RP S19) and found that it endowed the second binding moiety of RP S19 (L(131)DR) with a relatively higher binding affinity to the C5aR on a human mast cell line, HMC-1. In contrast to the C5aR, the second C5aR C5L2 worked as a decoy receptor. As a result, the mitogen-activated protein kinase (MAPK) downstream of the Gi protein exchanged extracellular-signal regulated kinase for p38MAPK. This alternative p38MAPK activation could be pharmacologically suppressed not only by the downregulation of phosphoinositide 3-kinase (PI3K) by LY294002, but also by the over-activation of protein kinase C by phorbol 12-myristate 13-acetate. The activation was reproduced upon C5a-C5aR interaction by a simultaneous suppression of PI3K and phospholipase C with LY294002 and U73122 at low concentrations. Moreover, p38MAPK phosphorylation upstream of the pertussis toxin-dependent extracellular Ca(2+) entry was also suppressed by high concentrations of MgCl(2), which blocks melastatin-type transient receptor potential Ca(2+) channels (TRPMs). The active conformation of C5aR upon the ligation by C5a, at least on HMC-1 cells, is changed by the additional interaction of the I(134)-H(145) peptide, which seems to guide the alternative activation of p38MAPK. This activation is then lified by a novel positive feedback loop between p38MAPK and TRPM.

C5aR2 Activation Broadly Modulates the Signaling and Function of Primary Human Macrophages

Publisher: The American Association of Immunologists

Date: 15-08-2020

DOI: 10.4049/JIMMUNOL.2000407

Abstract: The complement activation fragment C5a is a potent proinflammatory mediator that is increasingly recognized as an immune modulator. C5a acts through two C5a receptors, C5aR1 (C5aR, CD88) and C5aR2 (C5L2, GPR77), to powerfully modify multiple aspects of immune cell function. Although C5aR1 is generally acknowledged to be proinflammatory and immune-activating, the potential roles played by C5aR2 remain poorly defined. Despite studies demonstrating C5aR2 can modulate C5aR1 in human cells, it is not yet known whether C5aR2 functionality is limited to, or requires, C5aR1 activation or influences immune cells more broadly. The present study, therefore, aimed to characterize the roles of C5aR2 on the signaling and function of primary human monocyte–derived macrophages, using a C5aR2 agonist (Ac-RHYPYWR-OH P32) to selectively activate the receptor. We found that although C5aR2 activation with P32 by itself was devoid of any detectable MAPK signaling activities, C5aR2 agonism significantly d ened C5aR1-, C3aR-, and chemokine-like receptor 1 (CMKLR1)–mediated ERK signaling and altered intracellular calcium mobilization mediated by these receptors. Functionally, selective C5aR2 activation also downregulated cytokine production triggered by various TLRs (TLR2, TLR3, TLR4, and TLR7), C-type lectin receptors (Dectin-1, Dectin-2, and Mincle), and the cytosolic DNA sensor stimulator of IFN genes (STING). Surprisingly, activity at the C-type lectin receptors was particularly powerful, with C5aR2 activation reducing Mincle-mediated IL-6 and TNF-α generation by 80–90%. In sum, this study demonstrates that C5aR2 possesses pleiotropic functions in primary human macrophages, highlighting the role of C5aR2 as a powerful regulator of innate immune function.

Complement: The Emerging Architect of the Developing Brain

Publisher: Elsevier BV

Date: 06-2018

DOI: 10.1016/J.TINS.2018.03.009

Abstract: Complement activation products have long been associated with roles in the innate immune system, linking the humoral and cellular responses. However, among their recently described non-inflammatory roles, complement proteins also have multiple emerging novel functions in brain development. Within this context, separate proteins and pathways of complement have carved out physiological niches in the formation, development, and refinement of neurons. They demonstrate actions that are both reminiscent of peripheral immune actions and removed from them. We review here three key roles for complement proteins in the developing brain: progenitor proliferation, neuronal migration, and synaptic pruning.

An exhaustive tree-searching algorithm for high-resolution computer-assisted nucleotide sequence analysis

Publisher: Oxford University Press (OUP)

Date: 1985

DOI: 10.1093/BIOINFORMATICS/1.3.153

Abstract: A new computer search strategy has been devised for high-resolution nucleotide sequence analysis. The strategy differs from those used by earlier sequence analysing programs in that it is exhaustive and capable of detecting all possible homologies and other types of relationships between or within sequences irrespective of the pattern of matches and mismatches encountered. The implementation of this strategy into a working algorithm is described.

Comparative Agonist/Antagonist Responses in Mutant Human C5a Receptors Define the Ligand Binding Site

Publisher: Elsevier BV

Date: 05-2005

DOI: 10.1074/JBC.M410797200

Modulation of ligand selectivity by mutation of the first extracellular loop of the human C5a receptor 1 1Abbreviations: C5aR, human complement fragment 5a receptor; WT, wild-type; G105D, C5aR mutated

Publisher: Elsevier BV

Date: 06-2001

DOI: 10.1016/S0006-2952(01)00608-6

Abstract: The cyclic C5a receptor antagonist, phenylalanine [L-ornithine-proline-D-cyclohexylalanine-tryptophan-arginine] (F-[OPchaWR]), has approximately 1000-fold less affinity for the C5a receptor (C5aR) on murine polymorphonuclear leukocytes than on human. Analysis of C5aR from different species shows that a possible cause of this difference is the variation in the sequence of the first extracellular loop of the receptor. The mouse receptor contains Y at a position analogous to P(103) in the human receptor, and D at G(105). To test this hypothesis, we expressed human C5aR mutants (P(103)Y, G(105)D and the double mutant, P(103)Y/G(105)D) in RBL-2H3 cells and investigated the effects of these mutations on binding affinity and receptor activation. All three mutant receptors had a higher affinity for human C5a than the wild-type receptor, but showed no significant difference in the ability of F-[OPchaWR] to inhibit human C5a binding. However, all of the mutant receptors had substantially lower affinities for the weak agonist, C5a des Arg(74) (C5adR(74)), and two altered receptors (G(105)D and P(103)Y/G(105)D) had much lower affinities for the C-terminal C5a agonist peptide analogue, L-tyrosine-serine-phenylalanine-lysine-proline-methionine-proline-leucine-D-alanine-arginine (YSFKPMPLaR). Although it is unlikely that differences at these residues are responsible for variations in the potency of F-[OPchaWR] across species, residues in the first extracellular loop are clearly involved in the recognition of both C5a and C5a agonists. The complex effects of mutating these residues on the affinity and response to C5a, C5adR(74), and the peptide analogues provide evidence of different binding modes for these ligands on the C5aR.

A Commentary On: “NFκB-Activated Astroglial Release of Complement C3 Compromises Neuronal Morphology and Function Associated with Alzheimer’s Disease”. A cautionary note regarding C3aR

Publisher: Frontiers Media SA

Date: 07-05-2015

DOI: 10.3389/FIMMU.2015.00220

The microglial NLRP3 inflammasome is activated by amyotrophic lateral sclerosis proteins

Publisher: Wiley

Date: 09-10-2019

DOI: 10.1002/GLIA.23728

Abstract: Microglial NLRP3 inflammasome activation is emerging as a key contributor to neuroinflammation during neurodegeneration. Pathogenic protein aggregates such as β-amyloid and α-synuclein trigger microglial NLRP3 activation, leading to caspase-1 activation and IL-1β secretion. Both caspase-1 and IL-1β contribute to disease progression in the mouse SOD1

Complement peptide receptors (version 2020.5) in the IUPHAR/BPS Guide to Pharmacology Database

Publisher: Edinburgh University Library

Date: 12-11-2020

DOI: 10.2218/GTOPDB/F5/2020.5

Abstract: Complement peptide receptors (nomenclature as agreed by the NC-IUPHAR subcommittee on Complement peptide receptors [103]) are activated by the endogenous ~75 amino-acid anaphylatoxin polypeptides C3a and C5a, generated upon stimulation of the complement cascade. C3a and C5a exert their functions through binding to their receptors (C3aR and C5aR), causing cell activation and triggering cellular degranulation that contributes to the local inflammation.

Gut microbiota in ALS: possible role in pathogenesis?

Publisher: Informa UK Limited

Date: 29-05-2019

DOI: 10.1080/14737175.2019.1623026

Complement C5a inhibition reduces atherosclerosis in ApoE ^–/– mice

Publisher: Wiley

Date: 13-04-2011

DOI: 10.1096/FJ.10-174284

Abstract: The complement C5a receptor, CD88, is present on many of the cells found within human atherosclerotic plaques, but little is known about the role of C5a in atherogenesis. Using real-time PCR, we determined that ApoE(-/-) mice fed a normal diet express more aortic CD88 mRNA compared with controls, and this increase coincides with atherosclerotic lesion development (P<0.001 for 3- vs. 25-wk-old animals). Conversely, mRNA expression of the alternative C5a receptor, C5L2, in aortas of ApoE(-/-) mice, was lower than controls at all time points. Using immunohistochemistry, we confirmed the presence of CD88 on macrophages, smooth muscle cells, and activated endothelial cells in plaques from brachiocephalic arteries. Treatment of ApoE(-/-) mice with a CD88 antagonist (PMX53 3 mg/kg s.c. 3 ×/wk plus 1 mg/kg/d p.o.) for 25 wk reduced lesion size and lipid content in the plaque by ∼ 40% (P<0.05). Our study provides evidence for a proatherogenic role for C5a and identifies the CD88 antagonist PMX53 as a potential antiatherosclerotic drug.

Complement C5a Induces Renal Injury in Diabetic Kidney Disease by Disrupting Mitochondrial Metabolic Agility

Publisher: American Diabetes Association

Date: 17-10-2019

DOI: 10.2337/DB19-0043

Abstract: The sequelae of diabetes include microvascular complications such as diabetic kidney disease (DKD), which involves glucose-mediated renal injury associated with a disruption in mitochondrial metabolic agility, inflammation, and fibrosis. We explored the role of the innate immune complement component C5a, a potent mediator of inflammation, in the pathogenesis of DKD in clinical and experimental diabetes. Marked systemic elevation in C5a activity was demonstrated in patients with diabetes conventional renoprotective agents did not therapeutically target this elevation. C5a and its receptor (C5aR1) were upregulated early in the disease process and prior to manifest kidney injury in several erse rodent models of diabetes. Genetic deletion of C5aR1 in mice conferred protection against diabetes-induced renal injury. Transcriptomic profiling of kidney revealed diabetes-induced downregulation of pathways involved in mitochondrial fatty acid metabolism. Interrogation of the lipidomics signature revealed abnormal cardiolipin remodeling in diabetic kidneys, a cardinal sign of disrupted mitochondrial architecture and bioenergetics. In vivo delivery of an orally active inhibitor of C5aR1 (PMX53) reversed the phenotypic changes and normalized the renal mitochondrial fatty acid profile, cardiolipin remodeling, and citric acid cycle intermediates. In vitro exposure of human renal proximal tubular epithelial cells to C5a led to altered mitochondrial respiratory function and reactive oxygen species generation. These experiments provide evidence for a pivotal role of the C5a/C5aR1 axis in propagating renal injury in the development of DKD by disrupting mitochondrial agility, thereby establishing a new immunometabolic signaling pathway in DKD.

Inflammasomes in CNS Diseases

Publisher: Springer International Publishing

Date: 2018

DOI: 10.1007/978-3-319-89390-7_3

Abstract: Neuroinflammation is a common pathological feature in almost all neurological diseases and is a response triggered as a consequence of the chronic activation of the innate immune response in the CNS against a variety of stimuli, including infection, traumatic brain injury, toxic metabolites, aggregated proteins, or autoimmunity. Crucial mediators of this neurinflammatory process are the intracellular protein complexes known as inflammasomes which can be triggered by pathogens as well as pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs). However, chronic inflammasome activation can eventually result in cellular death and tissue damage, leading to the release of DAMPs that can reactivate the inflammasome, thereby propagating a vicious cycle of inflammation. The primary cells involved in CNS inflammasome activation are the immunocompetent microglia and the infiltrating macrophages into the CNS. However, astrocytes and neurons also express inflammasomes, and the understanding of how they are engaged in the pathogenesis of a variety of neurological diseases is crucial to develop effective therapeutic approaches for CNS pathologies that are propagated by chronic inflammasome activation. This chapter covers the activation mechanisms of relevant inflammasomes in the brain and summarizes their roles in the pathogenesis and progression of different neurological conditions.

Suppl video 2 from Neutrophil Conversion to a Tumor-Killing Phenotype Underpins Effective Microbial Therapy

Publisher: American Association for Cancer Research (AACR)

Date: 14-04-2023

DOI: 10.1158/0008-5472.22633199.V1

Abstract: Neutrophil interactions with LLC cells in unmanipulated and treated tumors.

Leucocyte expression of complement C5a receptors exacerbates infarct size after myocardial reperfusion injury

Publisher: Oxford University Press (OUP)

Date: 15-06-2014

DOI: 10.1093/CVR/CVU153

Abstract: Early reperfusion is mandatory for the treatment of acute myocardial infarction. This process, however, also induces additional loss of viable myocardium, called ischaemia-reperfusion (IR) injury. Complement activation plays an important role in IR injury, partly through binding of C5a to its major receptor (C5aR). We investigated the role of C5aR on infarct size and cardiac function in a model for myocardial IR injury. BALB/c (WT) mice and C5aR(-/-) mice underwent coronary occlusion for 30 min, followed by reperfusion. Infarct size, determined 24 h after IR, was reduced in C5aR(-/-) mice compared with WT mice (28.5 ± 2.1 vs. 35.7 ± 2.5%, P = 0.017). Bone marrow (BM) chimaera experiments showed that this effect was due to the absence of C5aR on circulating leucocytes, since a similar reduction in infarct size was observed in WT mice with C5aR-deficient BM cells (25.3 ± 2.2 vs. 34.6 ± 2.8%, P < 0.05), but not in C5aR(-/-) mice with WT BM cells. Reduced infarct size was associated with fewer neutrophils, T cells, and macrophages in the infarcted area 24 h after IR in C5aR(-/-) mice, and also with lower levels of Caspase-3/7 indicating less inflammation and apoptosis. Echocardiography 4 weeks after IR showed an improved ejection fraction in C5aR(-/-) mice (25.8 ± 5.5 vs. 19.2 ± 5.4%, P < 0.001). The absence of C5aR on circulating leucocytes reduces infarct size, is associated with reduced leucocyte infiltration and with less apoptosis in the infarcted myocardium, and improves cardiac function in a mouse model of myocardial IR injury. Selective blocking of C5aR might be a promising strategy to prevent myocardial IR injury.

Insights into the mechanism of C5aR inhibition by PMX53 via implicit solvent molecular dynamics simulations and docking

Publisher: Springer Science and Business Media LLC

Date: 12-08-2014

DOI: 10.1186/2046-1682-7-5

Senolytic therapy alleviates physiological human brain aging and COVID-19 neuropathology

Publisher: Cold Spring Harbor Laboratory

Date: 18-01-2023

DOI: 10.1101/2023.01.17.524329

Abstract: Aging is the primary risk factor for most neurodegenerative diseases, and recently coronavirus disease 2019 (COVID-19) has been associated with severe neurological manifestations that can eventually impact neurodegenerative conditions in the long-term. The progressive accumulation of senescent cells in vivo strongly contributes to brain aging and neurodegenerative co-morbidities but the impact of virus-induced senescence in the aetiology of neuropathologies is unknown. Here, we show that senescent cells accumulate in physiologically aged brain organoids of human origin and that senolytic treatment reduces inflammation and cellular senescence for which we found that combined treatment with the senolytic drugs dasatinib and quercetin rejuvenates transcriptomic human brain aging clocks. We further interrogated brain frontal cortex regions in postmortem patients who succumbed to severe COVID-19 and observed increased accumulation of senescent cells as compared to age-matched control brains from non-COVID-affected in iduals. Moreover, we show that exposure of human brain organoids to SARS-CoV-2 evoked cellular senescence, and that spatial transcriptomic sequencing of virus-induced senescent cells identified a unique SARS-CoV-2 variant-specific inflammatory signature that is different from endogenous naturally-emerging senescent cells. Importantly, following SARS-CoV-2 infection of human brain organoids, treatment with senolytics blocked viral retention and prevented the emergence of senescent corticothalamic and GABAergic neurons. Furthermore, we demonstrate in human ACE2 overexpressing mice that senolytic treatment ameliorates COVID-19 brain pathology following infection with SARS-CoV-2. In vivo treatment with senolytics improved SARS-CoV-2 clinical phenotype and survival, alleviated brain senescence and reactive astrogliosis, promoted survival of dopaminergic neurons, and reduced viral and senescence-associated secretory phenotype gene expression in the brain. Collectively, our findings demonstrate SARS-CoV-2 can trigger cellular senescence in the brain, and that senolytic therapy mitigates senescence-driven brain aging and multiple neuropathological sequelae caused by neurotropic viruses, including SARS-CoV-2.

Eph/Ephrin Signaling in Injury and Inflammation

Publisher: Elsevier BV

Date: 11-2012

DOI: 10.1016/J.AJPATH.2012.06.043

Abstract: The Eph/ephrin receptor-ligand system plays an important role in embryogenesis and adult life, principally by influencing cell behavior through signaling pathways, resulting in modification of the cell cytoskeleton and cell adhesion. There are 10 EphA receptors, and six EphB receptors, distinguished on sequence difference and binding preferences, that interact with the six glycosylphosphatidylinositol-linked ephrin-A ligands and the three transmembrane ephrin-B ligands, respectively. The Eph/ephrin proteins, originally described as developmental regulators that are expressed at low levels postembryonically, are re-expressed after injury to the optic nerve, spinal cord, and brain in fish, hibians, rodents, and humans. In rodent spinal cord injury, the up-regulation of EphA4 prevents recovery by inhibiting axons from crossing the injury site. Eph/ephrin proteins may be partly responsible for the phenotypic changes to the vascular endothelium in inflammation, which allows fluid and inflammatory cells to pass from the vascular space into the interstitial tissues. Specifically, EphA2/ephrin-A1 signaling in the lung may be responsible for pulmonary inflammation in acute lung injury. A role in T-cell maturation and chronic inflammation (heart failure, inflammatory bowel disease, and rheumatoid arthritis) is also reported. Although there remains much to learn about Eph/ephrin signaling in human disease, and specifically in injury and inflammation, this area of research raises the exciting prospect that novel therapies will be developed that precisely target these pathways.

The Complement Receptor C5aR2: A Powerful Modulator of Innate and Adaptive Immunity.

Publisher: The American Association of Immunologists

Date: 15-06-2019

DOI: 10.4049/JIMMUNOL.1900371

Abstract: Complement activation generates the core effector protein C5a, a potent immune molecule that is linked to multiple inflammatory diseases. Two C5a receptors, C5aR1 (C5aR, CD88) and C5aR2 (C5L2, GPR77), mediate the biological activities of C5a. Although C5aR1 has broadly acknowledged proinflammatory roles, C5aR2 remains at the center of controversy, with existing findings supporting both immune-activating and immune-d ening functions. Recent progress has been made toward resolving these issues. Instead of being a pure recycler and sequester of C5a, C5aR2 is capable of mediating its own set of signaling events and through these events exerting significant immunomodulatory effects not only toward C5aR1 but also other pattern recognition receptors and innate immune systems, such as NLRP3 inflammasomes. This review highlights the existing knowns and unknowns concerning C5aR2 and provides a timely update on recent breakthroughs which are expected to have a substantial impact on future fundamental and translational C5aR2 research.

Complement C5a induces the formation of neutrophil extracellular traps by myeloid-derived suppressor cells to promote metastasis

Publisher: Elsevier BV

Date: 03-2022

DOI: 10.1016/J.CANLET.2021.12.027

Abstract: Myeloid-derived suppressor cells (MDSCs) play a major role in cancer progression. In this study, we investigated the mechanisms by which complement C5a increases the capacity of polymorphonuclear MDSCs (PMN-MDSCs) to promote tumor growth and metastatic spread. Stimulation of PMN-MDSCs with C5a favored the invasion of cancer cells via a process dependent on the formation of neutrophil extracellular traps (NETs). NETosis was dependent on the production of high mobility group box 1 (HMGB1) by cancer cells. Moreover, C5a induced the surface expression of the HMGB1 receptors TLR4 and RAGE in PMN-MDSCs. In a mouse lung metastasis model, inhibition of C5a, C5a receptor-1 (C5aR1) or NETosis reduced the number of circulating-tumor cells (CTCs) and the metastatic burden. In support of the translational relevance of these findings, C5a was able to stimulate migration and NETosis in PMN-MDSCs obtained from lung cancer patients. Furthermore, myeloperoxidase (MPO)-DNA complexes, as markers of NETosis, were elevated in lung cancer patients and significantly correlated with C5a levels. In conclusion, C5a induces the formation of NETs from PMN-MDSCs in the presence of cancer cells, which may facilitate cancer cell dissemination and metastasis.

Treatment with a C5aR Antagonist Decreases Pathology and Enhances Behavioral Performance in Murine Models of Alzheimer’s Disease

Publisher: The American Association of Immunologists

Date: 15-07-2009

DOI: 10.4049/JIMMUNOL.0901005

Abstract: Alzheimer’s disease (AD) is an age-related dementia, characterized by amyloid plaques, neurofibrillary tangles, neuroinflammation, and neuronal loss in the brain. Components of the complement system, known to produce a local inflammatory reaction, are associated with the plaques and tangles in AD brain, and thus a role for complement-mediated inflammation in the acceleration or progression of disease has been proposed. A complement activation product, C5a, is known to recruit and activate microglia and astrocytes in vitro by activation of a G protein-coupled cell-surface C5aR. Here, oral delivery of a cyclic hexapeptide C5a receptor antagonist (PMX205) for 2–3 mo resulted in substantial reduction of pathological markers such as fibrillar amyloid deposits (49–62%) and activated glia (42–68%) in two mouse models of AD. The reduction in pathology was correlated with improvements in a passive avoidance behavioral task in Tg2576 mice. In 3xTg mice, PMX205 also significantly reduced hyperphosphorylated tau (69%). These data provide the first evidence that inhibition of a proinflammatory receptor-mediated function of the complement cascade (i.e., C5aR) can interfere with neuroinflammation and neurodegeneration in AD rodent models, suggesting a novel therapeutic target for reducing pathology and improving cognitive function in human AD patients.

Diabetes in an older Australian population

Publisher: Elsevier BV

Date: 09-1998

DOI: 10.1016/S0168-8227(98)00079-5

Abstract: To describe the prevalence of self-reported diabetes and undiagnosed diabetes using new fasting plasma glucose (FPG) criteria, and vascular associations with diabetes history in a representative s le of older Australians attending the population-based Blue Mountains Eye Study. 3654 people aged 49 years or older, representing 88% of permanent residents in two postcode areas west of Sydney, underwent a detailed medical and eye examination. This included history of diabetes, vascular events and vascular risk factors. Fasting pathology tests, including glucose, were obtained for 88% of these subjects. A diabetes history was given by 217 people (5.9%), including 7.0% of men and 5.2% of women. Elevated FPG (> or = 7.0 mmol/l) was found in a further 66 people (2.2% of persons who had FPG performed) and Impaired Fasting Glucose (FPG > or = 6.1 mmol/l and < 7.0 mmol/l) was found in a further 127 people (4.2%). History of diabetes was associated with an increased prevalence of obesity, elevated mean blood pressure and serum triglycerides, and lower mean serum cholesterol and HDL-cholesterol. Statistically significant associations were found between diabetes history and history of angina, acute myocardial infarction, stroke, gout and thyroid disease, after adjusting for age and sex using logistic regression. The vascular relationships with diabetes were stronger among people who currently smoked. This study has found similar diabetes prevalence to recently published Australian National Health Survey findings. Strong cross-sectional associations between diabetes history and vascular events and increased prevalence of vascular risk factors among older subjects with diabetes emphasise the need to address vascular risk factors in this group.

Is the Complement Activation Product C3a a Proinflammatory Molecule? Re-evaluating the Evidence and the Myth

Publisher: The American Association of Immunologists

Date: 15-04-2015

DOI: 10.4049/JIMMUNOL.1403068

Abstract: The complement activation product C3a is often described as a proinflammatory mediator, alongside its downstream cousin, C5a. However, emerging studies show that C3a has several anti-inflammatory facets in vivo. For ex le, in the acute inflammatory response, C3a acts in direct opposition to C5a, through preventing the accumulation of neutrophils in inflamed tissues by independently regulating their mobilization. This acute, protective, and opposing activity of C3a to C5a is also illustrated in models of septicemia. In this article, we reinvestigate the discovery and original classification of C3a as a proinflammatory mediator and highlight the emerging studies demonstrating anti-inflammatory effects for C3a in the immune response. It is our hope that this review illuminates these apparently contradictory roles for C3a and challenges the general dogma surrounding C3a, which, historically, has ubiquitously been described as a proinflammatory mediator. In light of this, we urge investigators to use “inflammatory modulator” as the descriptor for C3a.

Antiallodynic effects of alpha lipoic acid in an optimized RR-EAE mouse model of MS-neuropathic pain are accompanied by attenuation of upregulated BDNF-TrkB-ERK signaling in the dorsal horn of the spinal cord

Publisher: Wiley

Date: 04-05-2015

DOI: 10.1002/PRP2.137

The “C3aR Antagonist” SB290157 is a Partial C5aR2 Agonist

Publisher: Frontiers Media SA

Date: 21-01-2021

DOI: 10.3389/FPHAR.2020.591398

Abstract: Innate immune complement activation generates the C3 and C5 protein cleavage products C3a and C5a, defined classically as anaphylatoxins. C3a activates C3aR, while C5a activates two receptors (C5aR1 and C5aR2) to exert their immunomodulatory activities. The non-peptide compound, SB290157, was originally reported in 2001 as the first C3aR antagonist. In 2005, the first report on the non-selective nature of SB290157 was published, where the compound exerted clear agonistic, not antagonistic, activity in variety of cells. Other studies also documented the non-selective activities of this drug in vivo. These findings severely h er data interpretation regarding C3aR when using this compound. Unfortunately, given the dearth of C3aR inhibitors, SB290157 still remains widely used to explore C3aR biology (& publications to date). Given these issues, in the present study we aimed to further explore SB290157's pharmacological selectivity by screening the drug against three human anaphylatoxin receptors, C3aR, C5aR1 and C5aR2, using cell models. We identified that SB290157 exerts partial agonist activity at C5aR2 by mediating β -arrestin recruitment at higher compound doses. This translated to a functional outcome in both human and mouse primary macrophages, where SB290157 significantly d ened C5a-induced ERK signaling. We also confirmed that SB290157 acts as a potent agonist at human C3aR in transfected cells, but as an antagonist in primary human macrophages. Our results therefore provide even more caution against using SB290157 as a research tool to explore C3aR function. Given the reported immunomodulatory and anti-inflammatory activities of C5aR2 agonism, any function observed with SB290157 could be due to these off-target activities.

The Complement Receptor C5aR Controls Acute Inflammation and Astrogliosis following Spinal Cord Injury

Publisher: Society for Neuroscience

Date: 22-04-2015

DOI: 10.1523/JNEUROSCI.5218-14.2015

Abstract: This study investigated the role of the complement activation fragment C5a in secondary pathology following contusive spinal cord injury (SCI). C5ar −/− mice, which lack the signaling receptor for C5a, displayed signs of improved locomotor recovery and reduced inflammation during the first week of SCI compared with wild-type mice. Intriguingly, the early signs of improved recovery in C5ar −/− mice deteriorated from day 14 onward, with absence of C5aR ultimately leading to poorer functional outcomes, larger lesion volumes, reduced myelin content, and more widespread inflammation at 35 d SCI. Pharmacological blockade of C5aR with a selective antagonist (C5aR-A) during the first 7 d after SCI improved recovery compared with vehicle-treated mice, and this phenotype was sustained up to 35 d after injury. Consistent with observations made in C5ar −/− mice, these improvements were, however, lost if C5aR-A administration was continued into the more chronic phase of SCI. Signaling through the C5a-C5aR axis thus appears injurious in the acute period but serves a protective and/or reparative role in the post-acute phase of SCI. Further experiments in bone marrow chimeric mice suggested that the dual and opposing roles of C5aR on SCI outcomes primarily relate to its expression on CNS-resident cells and not infiltrating leukocytes. Additional in vivo and in vitro studies provided direct evidence that C5aR signaling is required during the postacute phase for astrocyte hyperplasia, hypertrophy, and glial scar formation. Collectively, these findings highlight the complexity of the inflammatory response to SCI and emphasize the importance of optimizing the timing of therapeutic interventions.

Anaphylatoxin receptor promiscuity for commonly used complement C5a peptide agonists

Publisher: Elsevier BV

Date: 11-2021

DOI: 10.1016/J.INTIMP.2021.108074

Abstract: The complement system is an essential component of innate immunity. Its activation generates the effector cleavage proteins, anaphylatoxins C3a and C5a, that exert activity by interacting with three structurally related seven-transmembrane receptors. C3a activates C3aR, whilst C5a interacts with both C5aR1 and C5aR2 with equal potency. Of the three receptors, C5aR1 in particular is considered the most functionally potent inflammatory driver and has been the major target for pharmacological development. Multiple peptidic C5a agonists have been developed to target C5aR1, with the full agonists EP54 (YSFKPMPLaR) and EP67 (YSFKDMP(MeL)aR), and the partial agonist C028 (C5a

Targeting ischemic brain injury with intravenous immunoglobulin

Publisher: Informa UK Limited

Date: 13-12-2007

DOI: 10.1517/14728222.12.1.19

Abstract: Intravenous immunoglobulin (IVIG) is a therapeutic modality approved for the treatment of autoimmune disorders. This review discusses how IVIG can prevent brain damage following ischemic stroke and discuss the potential mechanisms of action. Medline and the world wide web were searched and the relevant literature was classified under the following categories: IVIG, IVIG mechanism of action, and ischemic stroke injury mechanisms. Brain ischemia induces an inflammatory response that contributes to neuronal cell death. Because of its ability to block multiple molecular events, IVIG may have particularly strong neuroprotective action against ischemic brain injury. In light of the extensive clinical experience with IVIG for other indications, development of clinical trials to evaluate the use of IVIG in human stroke patients are warranted.

Absence of toll-like receptor 4 (TLR4) extends survival in the hSOD1^G93A mouse model of amyotrophic lateral sclerosis

Publisher: Springer Science and Business Media LLC

Date: 13-05-2015

DOI: 10.1186/S12974-015-0310-Z

Pivotal role for beta-1 integrin in neurovascular remodelling after ischemic stroke

Publisher: Elsevier BV

Date: 2010

DOI: 10.1016/J.EXPNEUROL.2009.10.007

Abstract: beta1 integrin is a cell surface molecule that is critical for endothelial cell adhesion, migration and survival during angiogenesis. In the present study we employed in vivo and in vitro models to elucidate the role of beta1 integrin in vascular remodelling and stroke outcomes. At 24 h after cerebral ischemia and reperfusion (I/R), the ischemic cortex (ipsilateral area) exhibited modest beta1 integrin immunoreactivity and a robust increase was observed at 72 h. Double-label immunohistochemical analysis for beta1 integrin with neuronal (NeuN), microglial (Iba-1), astrocyte (GFAP), progenitor cell (Ng2) and blood vessel (collagen 4) markers showed that beta1 integrin expression only localized to blood vessels. In vitro studies using cultured endothelial cells and a beta1 integrin blocking antibody confirmed that beta1 integrin is required for endothelial cell migration, proliferation and blood vessel formation. In vivo studies in the cerebral I/R model using the beta1 integrin blocking antibody further confirmed that beta1 integrin signaling is involved in vascular formation and recovery following ischemic stroke. Finally, we found that beta1 integrin is critically involved in functional deficits and survival after a stroke. These results suggest that beta1 integrin plays important roles in neurovascular remodelling and functional outcomes following stroke, and that targeting the beta1 integrin signalling may provide a novel strategy for modulating angiogenesis in ischemic stroke and other pathological conditions.

Dendritic Cell Function in Allostimulation Is Modulated by C5aR Signaling

Publisher: The American Association of Immunologists

Date: 15-11-2009

DOI: 10.4049/JIMMUNOL.0804186

Abstract: Regulation of T cell immunity by C5a has been suggested from recent studies. However, the underlying mechanisms, particularly the involved cells and biochemical basis, are not well defined. In this study, the direct modulation of dendritic cell (DC) activation and its function in T cell stimulation by C5a-C5aR interaction and the involved signaling pathways were investigated. We show that DCs from C5aR−/− mice and normal DCs treated with C5aR antagonist have less-activated phenotype characterized with increased IL-10 and decreased IL-12p70 production in response to LPS stimulation, lowered surface expression of MHC class II, B7.2, and consequently have reduced capacity to stimulate allospecific T cells. Conversely, C5a stimulation up-regulates DC activation and its function in allostimulation. Furthermore, stimulation of C5aR mediates the inhibition of cAMP production and protein kinase A activity and is involved in activation of PI3K/AKT and NF-κB signaling in DCs. These results demonstrate that C5a acts directly on C5aR expressed on DCs resulting in the cell activation and subsequently enhances its capacity for allospecific T cell stimulation. It also suggests that NF-κB signaling induced by down-regulation of cAMP/ protein kinase A pathway and up-regulation of PI3K/AKT pathway following C5a stimulation may contribute to up-regulation of DC function.

Targeting C5aR1 Increases the Therapeutic Window of Radiotherapy

Publisher: Cold Spring Harbor Laboratory

Date: 28-10-2020

DOI: 10.1101/2020.10.27.358036

Abstract: Engaging innate immune pathways is emerging as a productive way of achieving durable anti-tumor responses. However, systemic administration of these therapies can result in toxicity, deemed to be particularly problematic when combined with current standard-of-care cytotoxic treatments such as radiotherapy. Increasing the therapeutic window of radiotherapy may be achieved by using targeted therapies, however, few pre-clinical studies investigate both tumor and normal tissue responses in detail. Here we show that targeting innate immune receptor C5aR1 improves tumor radiation response while reducing radiation-induced normal tissue toxicity, thereby increasing the therapeutic window. Genetically or pharmacologically targeting C5aR1 increases both IL-10 expression in the small intestine and IL-10 secretion by tumor cells. Increased IL-10 attenuates RelA phosphorylation and increases apoptosis in tumor cells, leading to improved radiation responses in murine models. Of note, these radiosensitizing effects are tumor-specific since, in the gastrointestinal tract, targeting C5aR1 instead results in decreased crypt cell apoptosis reduced signs of histological damage and improved survival following total abdominal irradiation in mice. Furthermore, the potent and orally active C5aR1 inhibitor, PMX205, improves tumor radiation responses even in a context of reduced/absent CD8+ T cell infiltration. These data indicate that PMX205 can modulate cancer-cell intrinsic functions to potentiate anti-tumor radiation responses even in tumors displaying features of T-cell deficiency or exclusion. Finally, using a preclinical murine model allowing the simultaneous assessment of tumor and normal tissue radiation responses, we show that PMX205 treatment reduces histological and functional markers of small-bowel toxicity while affording a positive tumor response. Our data, therefore, suggest that targeting C5aR1 could be a promising approach for increasing the therapeutic window of radiotherapy.

Suppl video 1 from Neutrophil Conversion to a Tumor-Killing Phenotype Underpins Effective Microbial Therapy

Publisher: American Association for Cancer Research (AACR)

Date: 14-04-2023

DOI: 10.1158/0008-5472.22633202.V1

Abstract: Neutrophil migration before and after microbial bioparticle treatment.

Dysregulation of the complement cascade in the hSOD1^G93Atransgenic mouse model of amyotrophic lateral sclerosis

Publisher: Springer Science and Business Media LLC

Date: 26-09-2013

DOI: 10.1186/1742-2094-10-119

Abstract: Components of the innate immune complement system have been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS) however, a comprehensive examination of complement expression in this disease has not been performed. This study therefore aimed to determine the expression of complement components (C1qB, C4, factor B, C3/C3b, C5 and CD88) and regulators (CD55 and CD59a) in the lumbar spinal cord of hSOD1 G93A mice during defined disease stages. hSOD1 G93A and wild-type mice were examined at four different ages of disease progression. mRNA and protein expression of complement components and regulators were examined using quantitative PCR, western blotting and ELISA. Localisation of complement components within lumbar spinal cord was investigated using immunohistochemistry. Statistical differences between hSOD1 G93A and wild-type mice were analysed using a two-tailed t -test at each stage of disease progression. We found several early complement factors increased as disease progressed, whilst complement regulators decreased suggesting overall increased complement activation through the classical or alternative pathways in hSOD1 G93A mice. CD88 was also increased during disease progression, with immunolocalisation demonstrating expression on motor neurons and increasing expression on microglia surrounding the regions of motor neuron death. These results indicate that local complement activation and increased expression of CD88 may contribute to motor neuron death and ALS pathology in the hSOD1 G93A mouse. Hence, reducing complement-induced inflammation could be an important therapeutic strategy to treat ALS.

The Role of the Complement System and the Activation Fragment C5a in the Central Nervous System

Publisher: Springer Science and Business Media LLC

Date: 11-09-2009

DOI: 10.1007/S12017-009-8085-Y

Abstract: The complement system is a pivotal component of the innate immune system which protects the host from infection and injury. Complement proteins can be induced in all cell types within the central nervous system (CNS), where the pathway seems to play similar roles in host defense. Complement activation produces the C5 cleavage fragment C5a, a potent inflammatory mediator, which recruits and activates immune cells. The primary cellular receptor for C5a, the C5a receptor (CD88), has been reported to be on all CNS cells, including neurons and glia, suggesting a functional role for C5a in the CNS. A second receptor for C5a, the C5a-like receptor 2 (C5L2), is also expressed on these cells however, little is currently known about its potential role in the CNS. The potent immune and inflammatory actions of complement activation are necessary for host defense. However, if over-activated, or left unchecked it promotes tissue injury and contributes to brain disease pathology. Thus, complement activation, and subsequent C5a generation, is thought to play a significant role in the progression of CNS disease. Paradoxically, complement may also exert a neuroprotective role in these diseases by aiding in the elimination of aggregated and toxic proteins and debris which are a principal hallmark of many of these diseases. This review will discuss the expression and known roles for complement in the CNS, with a particular focus on the pro-inflammatory end-product, C5a. The possible overarching role for C5a in diseases of the CNS is reviewed, and the therapeutic potential of blocking C5a/CD88 interaction is evaluated.

COVID-19: Complement, Coagulation, and Collateral Damage

Publisher: The American Association of Immunologists

Date: 15-09-2020

DOI: 10.4049/JIMMUNOL.2000644

Abstract: Coronavirus disease of 2019 (COVID-19) is a highly contagious respiratory infection that is caused by the severe acute respiratory syndrome coronavirus 2. Although most people are immunocompetent to the virus, a small group fail to mount an effective antiviral response and develop chronic infections that trigger hyperinflammation. This results in major complications, including acute respiratory distress syndrome, disseminated intravascular coagulation, and multiorgan failure, which all carry poor prognoses. Emerging evidence suggests that the complement system plays a key role in this inflammatory reaction. Indeed, patients with severe COVID-19 show prominent complement activation in their lung, skin, and sera, and those in iduals who were treated with complement inhibitors all recovered with no adverse reactions. These and other studies hint at complement’s therapeutic potential in these sequalae, and thus, to support drug development, in this review, we provide a summary of COVID-19 and review complement’s role in COVID-19 acute respiratory distress syndrome and coagulopathy.

Haematology and serum biochemistry of the tammar wallaby, Macropus eugenii

Publisher: Springer Science and Business Media LLC

Date: 10-2002

DOI: 10.1007/S005800200024

Systemic inhibition of the membrane attack complex impedes neuroinflammation in chronic relapsing experimental autoimmune encephalomyelitis

Publisher: Springer Science and Business Media LLC

Date: 03-05-2018

DOI: 10.1186/S40478-018-0536-Y

The C5a receptor antagonist PMX205 ameliorates experimentally induced colitis associated with increased IL‐4 and IL‐10

Publisher: Wiley

Date: 20-12-2012

DOI: 10.1111/J.1476-5381.2012.02183.X

Suppl video 3 from Neutrophil Conversion to a Tumor-Killing Phenotype Underpins Effective Microbial Therapy

Publisher: American Association for Cancer Research (AACR)

Date: 14-04-2023

DOI: 10.1158/0008-5472.22633196

Abstract: Neutrophils engage in multiple interactions with LLC tumor cells following microbial bioparticle treatment.

Supplementary Data from Neutrophil Conversion to a Tumor-Killing Phenotype Underpins Effective Microbial Therapy

Publisher: American Association for Cancer Research (AACR)

Date: 14-04-2023

DOI: 10.1158/0008-5472.22633187.V1

Abstract: SUPPLEMENTARY FIGURES 1-10 SUPPLEMENTARY TABLE and VIDEO LEGENDS EXTENDED MATERIALS AND METHODS

Key factors influencing the incidence of hemolysis: a critical appraisal of current evidence.

Publisher: Informa UK Limited

Date: 26-12-2016

DOI: 10.1080/10408363.2016.1250247

Abstract: Hemolysis is a leading cause of pre-analytical laboratory errors. The identification of contributing factors is an important step towards the development of effective practices to reduce and prevent hemolysis. We performed a review of PUBMED, Embase, Medline and CINAHL to identify articles published between January 2000 and August 2016 that identified factors influencing in vitro hemolysis rates. The 40 studies included in this review provide excellent evidence that hemolysis rates are higher in Emergency Departments (EDs), for non-antecubital draws, for specimens drawn using an intravenous catheter compared to venipuncture and for s les transported by pneumatic tube compared to by hand. There is also good evidence that hemolysis rates are higher when specimens are not collected by professional phlebotomists, larger volume specimen tubes are used, specimen tubes are filled less than halfway and tourniquet time is greater than one minute. The results of this review suggest that hospitals and clinical laboratories should consider deploying phlebotomists in EDs, drawing all blood through a venipuncture, using the antecubital region as the optimum blood collection site and transporting specimens by laboratory assistant/other personnel, or if this in not practical, ensuring that pneumatic transport systems are validated, maintained and monitored. Studies also recommend making hemolysis a hospital-wide issue and ensuring high-quality staff training and adherence to standard operating procedures to reduce hemolysis rates. Awareness of the factors that influence hemolysis rates, and adoption of strategies to mitigate these risk factors, is an important step towards creating quality practices to reduce hemolysis rates and improve the quality of patient care.

Suppl video 2 from Neutrophil Conversion to a Tumor-Killing Phenotype Underpins Effective Microbial Therapy

Publisher: American Association for Cancer Research (AACR)

Date: 14-04-2023

DOI: 10.1158/0008-5472.22633199

Abstract: Neutrophil interactions with LLC cells in unmanipulated and treated tumors.

Innate Immunity in ALS

Publisher: InTech

Date: 20-01-2012

DOI: 10.5772/30341

Role for terminal complement activation in amyotrophic lateral sclerosis disease progression

Publisher: Proceedings of the National Academy of Sciences

Date: 31-12-2013

DOI: 10.1073/PNAS.1321248111

Suppl video 4 from Neutrophil Conversion to a Tumor-Killing Phenotype Underpins Effective Microbial Therapy

Publisher: American Association for Cancer Research (AACR)

Date: 14-04-2023

DOI: 10.1158/0008-5472.22633193

Abstract: Neutrophil interactions with LLC cells lead to tumor cell blebbing.

TDP-43 Puts the STING in ALS

Publisher: Elsevier BV

Date: 02-2021

DOI: 10.1016/J.TINS.2020.12.001

Suppl video 4 from Neutrophil Conversion to a Tumor-Killing Phenotype Underpins Effective Microbial Therapy

Publisher: American Association for Cancer Research (AACR)

Date: 14-04-2023

DOI: 10.1158/0008-5472.22633193.V1

Abstract: Neutrophil interactions with LLC cells lead to tumor cell blebbing.

Complement drives circuit modulation in the adult brain

Publisher: Elsevier BV

Date: 07-2022

DOI: 10.1016/J.PNEUROBIO.2022.102282

Abstract: Once widely considered an immune-privileged organ, the brain is now known to be intimately intertwined with immune-system activation. In particular, the complement system, an enzymatic cascade conferring innate immunity, has crucial functions for several neurodevelopmental and neuromigratory mechanisms. Recent advances have demonstrated the neurological importance of complement activation in the adult brain, whereby phagocytosis of weakened synapses biologically encodes "forgetting" of information through complement activation. Neurophysiologically, complement factors can also influence the brain's computational processes, increasing neuronal calcium influx and neurotransmitter release and altering synaptic strength. The complement system's effects on synaptic connectivity can also be observed in many pathological conditions including epilepsy, schizophrenia, and viral-induced cognitive deficits, where perturbations of complement-stimulated synaptic remodelling lead to severe dysfunction. In this review we provide an overview of current knowledge for complement in neurodevelopment, and examine recent evidence highlighting a critical physiological role of complement in the plasticity of the adult brain. This is especially relevant due to the explosion of complement-targeted therapeutics in clinical trials to treat neurological disorders.

Absence of receptor for advanced glycation end product (RAGE) reduces inflammation and extends survival in the hSOD1^G93A mouse model of amyotrophic lateral sclerosis

Publisher: Cold Spring Harbor Laboratory

Date: 05-2020

DOI: 10.1101/2020.05.01.071944

Abstract: Amyotrophic lateral sclerosis (ALS) is a fatal and rapidly progressing motor neuron degenerative disease that is without effective treatment. The receptor for advanced glycation end products (RAGE) is a major component of the innate immune system that has been implicated in ALS pathogenesis. However, the contribution of RAGE signaling to the neuroinflammation that underlies ALS neurodegeneration remains unknown. The present study therefore generated SOD1 G93A mice lacking RAGE, and compared them to SOD1 G93A transgenic ALS mice in respect to disease progression (i.e. body weight, survival and muscle strength), neuroinflammation and denervation markers in the spinal cord and tibialis anterior muscle. We found that complete absence of RAGE signaling exerted a protective effect on SOD1 G93A pathology, slowing disease progression and significantly extending survival by ∼3 weeks, and improving motor function (rotarod and grip strength). This was associated with reduced microgliosis, cytokines, innate immune factors (complement, TLRs, inflammasomes), and oxidative stress in the spinal cord, and a reduction of denervation markers in the tibialis anterior muscle. We also documented that RAGE mRNA expression was significantly increased in the spinal cord and muscles of preclinical SOD1 and TDP43 models of ALS, supporting a widespread involvement for RAGE in ALS pathology. In summary, our results indicate that RAGE signalling drives neuroinflammation and contributes to neurodegeneration in ALS, and highlights RAGE as a potential immune therapeutic target for ALS.

Derivation of ligands for the complement C3a receptor from the C-terminus of C5a

Publisher: Elsevier BV

Date: 12-2014

DOI: 10.1016/J.EJPHAR.2014.10.041

Distinct roles of the anaphylatoxin receptors C3aR, C5aR1 and C5aR2 in experimental meningococcal infections

Publisher: Informa UK Limited

Date: 2019

DOI: 10.1080/21505594.2019.1640035

Phagocytosis of live and dead Escherichia coli and Staphylococcus aureus in human whole blood is markedly reduced by combined inhibition of C5aR1 and CD14

Publisher: Elsevier BV

Date: 08-2019

DOI: 10.1016/J.MOLIMM.2019.03.014

Abstract: Sepsis is a dysregulated host response to infection. The aim of this study was to investigate the effects of complement- and CD14 inhibition on phagocytosis of live and dead Gram-negative and Gram-positive bacteria in human whole blood. Lepirudin-anticoagulated blood was incubated with live or dead E. coli or S. aureus at 37 °C for 120 min with or without the C5aR1 antagonist PMX53 and/or anti-CD14. Granulocyte and monocyte phagocytosis were measured by flow cytometry, and five plasma cytokines by multiplex, yielding a total of 28 mediators of inflammation tested for. 16/28 conditions were reduced by PMX53, 7/28 by anti-CD14, and 24/28 by combined PMX53 and CD14 inhibition. The effect of complement inhibition was quantitatively more pronounced, in particular for the responses to S. aureus. The effect of anti-CD14 was modest, except for a marked reduction in INF-β. The responses to live and dead S. aureus were equally inhibited, whereas the responses to live E. coli were inhibited less than those to dead E. coli. C5aR1 inhibited phagocytosis-induced inflammation by live and dead E. coli and S. aureus. CD14 blockade potentiated the effect of C5aR1 blockade, thus attenuating inflammation.

Complement peptide receptors in GtoPdb v.2021.3

Publisher: Edinburgh University Library

Date: 02-09-2021

DOI: 10.2218/GTOPDB/F5/2021.3

Abstract: Complement peptide receptors (nomenclature as agreed by the NC-IUPHAR subcommittee on Complement peptide receptors [107]) are activated by the endogenous ~75 amino-acid anaphylatoxin polypeptides C3a and C5a, generated upon stimulation of the complement cascade. C3a and C5a exert their functions through binding to their receptors (C3aR, C5aR1 and C5aR2), causing cell recruitment and triggering cellular degranulation that contributes to local inflammation.

The Peripheral Immune System and Amyotrophic Lateral Sclerosis

Publisher: Frontiers Media SA

Date: 21-04-2020

DOI: 10.3389/FNEUR.2020.00279

Complement C3a receptor modulates embryonic neural progenitor cell proliferation and cognitive performance

Publisher: Elsevier BV

Date: 09-2018

DOI: 10.1016/J.MOLIMM.2018.06.271

Abstract: The complement system of innate immunity is emerging as a novel player in neurodevelopmental processes. The receptor for C3a, C3aR, shares a close evolutionary and functional relationship with C5a receptors. Whilst the C5a receptor, C5aR1, has been demonstrated to promote embryonic neural stem cell proliferation, little is known about the role of C3aR in this process. Here we show that C3aR is expressed in a similar manner to C5aR1 in mice, at the apical pole of the embryonic ventricular zone, though it has an opposing function. Using in utero delivery of C3aR agonist and antagonist compounds to the embryonic ventricle, we demonstrate that C3aR functions to decrease proliferation of apical neural progenitor cells (NPC). Intriguingly, C3aR

Inflammasome inhibition prevents α-synuclein pathology and dopaminergic neurodegeneration in mice

Publisher: American Association for the Advancement of Science (AAAS)

Date: 31-10-2018

DOI: 10.1126/SCITRANSLMED.AAH4066

Abstract: Oral treatment with a brain-penetrant NLRP3 inhibitor has protective effects in preclinical models of Parkinson’s disease.

Therapeutic targeting of complement to modify disease course and improve outcomes in neurological conditions

Publisher: Elsevier BV

Date: 06-2016

DOI: 10.1016/J.SMIM.2016.03.015

Abstract: The recognition that complement proteins are abundantly present and can have pathological roles in neurological conditions offers broad scope for therapeutic intervention. Accordingly, an increasing number of experimental investigations have explored the potential of harnessing the unique activation pathways, proteases, receptors, complexes, and natural inhibitors of complement, to mitigate pathology in acute neurotrauma and chronic neurodegenerative diseases. Here, we review mechanisms of complement activation in the central nervous system (CNS), and explore the effects of complement inhibition in cerebral ischemic-reperfusion injury, traumatic brain injury, spinal cord injury, Alzheimer's disease, amyotrophic lateral sclerosis, Parkinson's disease and Huntington's disease. We consider the challenges and opportunities arising from these studies. As complement therapies approach clinical translation, we provide perspectives on how promising complement-targeted therapeutics could become part of novel and effective future treatment options to improve outcomes in the initiation and progression stages of these debilitating CNS disorders.

The Australian Reproductive Genetic Carrier Screening Project (Mackenzie’s Mission)

Publisher: MDPI AG

Date: 28-10-2022

DOI: 10.3390/JPM12111781

Abstract: Reproductive genetic carrier screening (RGCS) provides people with information about their chance of having children with autosomal recessive or X-linked genetic conditions, enabling informed reproductive decision-making. RGCS is recommended to be offered to all couples during preconception or in early pregnancy. However, cost and a lack of awareness may prevent access. To address this, the Australian Government funded Mackenzie’s Mission—the Australian Reproductive Genetic Carrier Screening Project. Mackenzie’s Mission aims to assess the acceptability and feasibility of an easily accessible RGCS program, provided free of charge to the participant. In study Phase 1, implementation needs were mapped, and key study elements were developed. In Phase 2, RGCS is being offered by healthcare providers educated by the study team. Reproductive couples who provide consent are screened for over 1200 genes associated with serious, childhood-onset genetic conditions. Those with an increased chance result are provided comprehensive genetic counseling support. Reproductive couples, recruiting healthcare providers, and study team members are also invited to complete surveys and/or interviews. In Phase 3, a mixed-methods analysis will be undertaken to assess the program outcomes, psychosocial implications and implementation considerations alongside an ongoing bioethical analysis and a health economic evaluation. Findings will inform the implementation of an ethically robust RGCS program.

Complement C5aR1 Signaling Promotes Polarization and Proliferation of Embryonic Neural Progenitor Cells through PKCζ

Publisher: Society for Neuroscience

Date: 28-04-2020

DOI: 10.1523/JNEUROSCI.0525-17.2017

Abstract: The complement system, typically associated with innate immunity, is emerging as a key controller of nonimmune systems including in development, with recent studies linking complement mutations with neurodevelopmental disease. A key effector of the complement response is the activation fragment C5a, which, through its receptor C5aR1, is a potent driver of inflammation. Surprisingly, C5aR1 is also expressed during early mammalian embryogenesis however, no clearly defined function is ascribed to C5aR1 in development. Here we demonstrate polarized expression of C5aR1 on the apical surface of mouse embryonic neural progenitor cells in vivo and on human embryonic stem cell-derived neural progenitors. We also show that signaling of endogenous C5a during mouse embryogenesis drives proliferation of neural progenitor cells within the ventricular zone and is required for normal brain histogenesis. C5aR1 signaling in neural progenitors was dependent on atypical protein kinase C ζ, a mediator of stem cell polarity, with C5aR1 inhibition reducing proliferation and symmetric ision of apical neural progenitors in human and mouse models. C5aR1 signaling was shown to promote the maintenance of cell polarity, with exogenous C5a increasing the retention of polarized rosette architecture in human neural progenitors after physical or chemical disruption. Transient inhibition of C5aR1 during neurogenesis in developing mice led to behavioral abnormalities in both sexes and MRI-detected brain microstructural alterations, in studied males, demonstrating a requirement of C5aR1 signaling for appropriate brain development. This study thus identifies a functional role for C5a–C5aR1 signaling in mammalian neurogenesis and provides mechanistic insight into recently identified complement gene mutations and brain disorders. SIGNIFICANCE STATEMENT The complement system, traditionally known as a controller of innate immunity, now stands as a multifaceted signaling family with a broad range of physiological actions. These include roles in the brain, where complement activation is associated with diseases, including epilepsy and schizophrenia. This study has explored complement regulation of neurogenesis, identifying a novel relationship between the complement activation peptide C5a and the neural progenitor proliferation underpinning formation of the mammalian brain. C5a was identified as a regulator of cell polarity, with inhibition of C5a receptors during embryogenesis leading to abnormal brain development and behavioral deficits. This work demonstrates mechanisms through which dysregulation of complement causes developmental disease and highlights the potential risk of complement inhibition for therapeutic purposes in pregnancy.

New tricks for an ancient system: Physiological and pathological roles of complement in the CNS

Publisher: Elsevier BV

Date: 10-2018

DOI: 10.1016/J.MOLIMM.2018.06.264

Complement: Bridging the innate and adaptive immune systems in sterile inflammation

Publisher: Oxford University Press (OUP)

Date: 17-03-2020

DOI: 10.1002/JLB.3MIR0220-270R

Abstract: The complement system is a collection of soluble and membrane-bound proteins that together act as a powerful lifier of the innate and adaptive immune systems. Although its role in infection is well established, complement is becoming increasingly recognized as a key contributor to sterile inflammation, a chronic inflammatory process often associated with noncommunicable diseases. In this context, damaged tissues release danger signals and trigger complement, which acts on a range of leukocytes to augment and bridge the innate and adaptive immune systems. Given the detrimental effect of chronic inflammation, the complement system is therefore well placed as an anti-inflammatory drug target. In this review, we provide a general outline of the sterile activators, effectors, and targets of the complement system and a series of ex les (i.e., hypertension, cancer, allograft transplant rejection, and neuroinflammation) that highlight complement’s ability to bridge the 2 arms of the immune system.

Editorial: The Role of Complement in Tumors

Publisher: Frontiers Media SA

Date: 11-02-2020

DOI: 10.3389/FIMMU.2020.00139

Chronic Helminth Infection Perturbs the Gut-Brain Axis, Promotes Neuropathology, and Alters Behavior

Publisher: Oxford University Press (OUP)

Date: 15-02-2018

DOI: 10.1093/INFDIS/JIY092

Abstract: Helminth infections in children are associated with impaired cognitive development however, the biological mechanisms for this remain unclear. Using a murine model of gastrointestinal helminth infection, we demonstrate that early-life exposure to helminths promotes local and systemic inflammatory responses and transient changes in the gastrointestinal microbiome. Behavioral and cognitive analyses performed 9-months postinfection revealed deficits in spatial recognition memory and an anxiety-like behavioral phenotype in worm-infected mice, which was associated with neuropathology and increased microglial activation within the brain. This study demonstrates a previously unrecognized mechanism through which helminth infections may influence cognitive function, via perturbations in the gut-immune-brain axis.

Neutrophils - A key component of ischemia-reperfusion injury

Publisher: Ovid Technologies (Wolters Kluwer Health)

Date: 12-2013

DOI: 10.1097/SHK.0000000000000044

Genetic testing [1]

Publisher: Elsevier BV

Date: 03-1996

DOI: 10.1016/S0140-6736(96)91235-0

Mitochondrial C5aR1 activity in macrophages controls IL-1β production underlying sterile inflammation

Publisher: American Association for the Advancement of Science (AAAS)

Date: 24-12-2021

DOI: 10.1126/SCIIMMUNOL.ABF2489

Abstract: Mitochondrial C5aR1 signaling is required for proinflammatory macrophage activity during crystal-induced sterile inflammation.

Supplementary Data from Neutrophil Conversion to a Tumor-Killing Phenotype Underpins Effective Microbial Therapy

Publisher: American Association for Cancer Research (AACR)

Date: 14-04-2023

DOI: 10.1158/0008-5472.22633187

Abstract: SUPPLEMENTARY FIGURES 1-10 SUPPLEMENTARY TABLE and VIDEO LEGENDS EXTENDED MATERIALS AND METHODS

A validated quantitative method for the assessment of neuroprotective barrier impairment in neurodegenerative disease models

Publisher: Wiley

Date: 22-07-2020

DOI: 10.1111/JNC.15119

Abstract: The blood–brain barrier (BBB) and blood–spinal cord barrier (BSCB) are highly specialized structures that limit molecule entry from the blood and maintain homeostasis within the central nervous system (CNS). BBB and BSCB breakdown are associated with multiple neurodegenerative diseases. Given the key role of neuroprotective barrier impairment in neurodegeneration, it is important to identify an effective quantitative method to assess barrier integrity in animal models. In this study, we developed and validated a quantitative method for assessing BBB and BSCB integrity using sodium fluorescein, a compound that outperformed other fluorescent dyes. We demonstrated using this method that multiple CNS regions progressively increase in permeability in models of Huntington’s disease and amyotrophic lateral sclerosis, whereas biphasic disruption occurred in a mouse model of Alzheimer’s disease with disease progression. Collectively, we report a quantitative fluorometric marker with validated reproducible experimental methods that allows the effective assessment of BBB and BSCB integrity in animal models. This method could be useful to further the understanding of the contribution of these neuroprotective barriers to neurodegeneration processes. image

The Alternative Receptor for Complement Component 5a, C5aR2, Conveys Neuroprotection in Traumatic Spinal Cord Injury

Publisher: Mary Ann Liebert Inc

Date: 15-06-2017

DOI: 10.1089/NEU.2016.4701

Abstract: This study investigated the role of the alternative receptor for complement activation fragment C5a, C5aR2, in secondary inflammatory pathology after contusive spinal cord injury (SCI) in mice. C5ar2

Preclinical Pharmacokinetics of Complement C5a Receptor Antagonists PMX53 and PMX205 in Mice

Publisher: American Chemical Society (ACS)

Date: 30-01-2020

DOI: 10.1021/ACSOMEGA.9B03735

Supplementary Table 1 from Neutrophil Conversion to a Tumor-Killing Phenotype Underpins Effective Microbial Therapy

Publisher: American Association for Cancer Research (AACR)

Date: 14-04-2023

DOI: 10.1158/0008-5472.22633184

Abstract: Characterization of neutrophil populations in single cell analysis.

Intrinsic bias at non-canonical, β-arrestin-coupled seven transmembrane receptors

Publisher: Cold Spring Harbor Laboratory

Date: 02-02-2021

DOI: 10.1101/2021.02.02.429298

Abstract: G protein-coupled receptors (GPCRs) are typically characterized by their seven transmembrane (7TM) architecture, and interaction with two universal signal-transducers namely, the heterotrimeric G-proteins and β-arrestins (βarrs). Synthetic ligands and receptor mutants have been designed to elicit transducer-coupling preferences and distinct downstream signaling outcomes for many GPCRs. This raises the question if some naturally-occurring 7TMRs may selectively engage one of these two signal-transducers, even in response to their endogenous agonists. Although there are scattered hints in the literature that some 7TMRs lack G-protein coupling but interact with βarrs, an in-depth understanding of their transducer-coupling preference, GRK-engagement, downstream signaling and structural mechanism remains elusive. Here, we use an array of cellular, biochemical and structural approaches to comprehensively characterize two non-canonical 7TMRs namely, the human decoy D6 receptor (D6R) and the human complement C5a receptor (C5aR2), in parallel with their canonical GPCR counterparts, CCR2 and C5aR1, respectively. We discover that D6R and C5aR2 couple exclusively to βarrs, exhibit distinct GRK-preference, and activate non-canonical downstream signaling partners. We also observe that βarrs, in complex with these receptors, adopt distinct conformations compared to their canonical GPCR counterparts despite being activated by a common natural agonist. Our study therefore establishes D6R and C5aR2 as bona-fide arrestin-coupled receptors (ACRs), and provides important insights into their regulation by GRKs and downstream signaling with direct implications for biased agonism.

The Role of the N-terminal Domain of the Complement Fragment Receptor C5L2 in Ligand Binding

Publisher: Elsevier BV

Date: 02-2007

DOI: 10.1074/JBC.M609178200

Elevated complement factor C5a in maternal and umbilical cord plasma in preeclampsia

Publisher: Elsevier BV

Date: 04-2013

DOI: 10.1016/J.JRI.2012.11.006

Abstract: Preecl sia is a leading cause of morbidity and mortality worldwide, encompassing significant short- and long-term health sequelae. Recently, there has been accumulating evidence for a role of the complement system in the pathogenesis of numerous complications of pregnancy, including preecl sia. The present cross-sectional study compared the plasma concentrations of complement factors C3a and C5a between normotensive pregnancies and pregnancies complicated with either preecl sia or gestational hypertension alone. We found that maternal plasma C5a concentration was significantly higher in preecl tic pregnancy than in pregnancy affected by gestational hypertension alone or normotensive pregnancy. Umbilical cord plasma C5a concentrations were also higher in pregnancies complicated by preecl sia compared to gestational hypertension or normotensive pregnancy. Maternal and cord plasma C5a concentrations were significantly correlated, suggesting that C5a can freely diffuse between maternal and fetal circulation. There were no significant differences in C3a concentrations in maternal or cord plasma between any groups. These results support the hypothesis that C5a may play a role in preecl sia, but not in gestational hypertension.

Complement in stem cells and development

Publisher: Elsevier BV

Date: 06-2018

DOI: 10.1016/J.SMIM.2018.02.009

Abstract: From its discovery in the late nineteenth century, as a 'complement' to the cellular immune response, the complement system has been widely affirmed as a powerful controller of innate and adaptive immune responses. In recent decades however, new roles for complement have been discovered, with multiple complement proteins now known to function in a broad array of non-immune systems. This includes during development, where complement exerts control over stem cell populations from fertilization and implantation throughout embryogenesis and beyond post-natal development. It is involved in processes as erse as cell localisation, tissue morphogenesis, and the growth and refinement of the brain. Such physiological actions of complement have also been described in adult stem cell populations, with roles in proliferation, differentiation, survival, and regeneration. With such a broad range of complement functions now described, it is likely that current research only describes a fraction of the full reach of complement proteins. Here, we review how complement control of physiological cell processes has been harnessed in stem cell populations throughout both development and in adult physiology.

Co-ordinated expression of innate immune molecules during mouse neurulation

Publisher: Elsevier BV

Date: 12-2015

DOI: 10.1016/J.MOLIMM.2015.09.004

Abstract: The innate immune system is the first line of defence against pathogens and infection. Recently, it has become apparent that many innate immune factors have roles outside of immunity and there is growing evidence that these factors play important functional roles during the development of a range of model organisms. Several studies have documented developmental expression of in idual factors of the toll-like receptor and complement systems, and we recently demonstrated a key role for complement C5a receptor (C5aR1) signalling in neural tube closure in mice. Despite these emerging studies, a comprehensive expression analysis of these molecules in embryonic development is lacking. In the current study, we therefore, examined the expression of key innate immune factors in the early development period of neurulation (7.5-10.5dpc) in mice. We found that complement factor genes were differentially expressed during this period of murine development. Interestingly, the expression patterns we identified preclude activation of the classical and alternative pathways and formation of the membrane attack complex. Additionally, several other classes of innate immune molecules were expressed during the period of neurulation, including toll-like receptors (TLR-2, -3, -4 and -9), receptor for advanced glycation end-products (RAGE), and their signalling adapters (TRAF-4, TRAF-6, TAK-1 and MyD88). Taken together, this study highlights a number of innate immune factors as potential novel players in early embryonic development.

Commentary: Beyond C4: Analysis of the complement gene pathway shows enrichment for IQ in patients with psychotic disorders and healthy controls

Publisher: Frontiers Media SA

Date: 04-12-2019

DOI: 10.3389/FIMMU.2019.02853

A validated quantitative method for the assessment of neuroprotective barrier impairment in neurodegenerative disease models

Publisher: Cold Spring Harbor Laboratory

Date: 08-03-2020

DOI: 10.1101/2020.03.06.979930

Abstract: The blood brain barrier (BBB) and blood spinal cord barrier (BSCB) are highly specialised structures that limit molecule entry from the blood and maintain homeostasis within the central nervous system (CNS). BBB and BSCB breakdown are associated with multiple neurodegenerative diseases. Given the key role of neuroprotective barrier impairment in neurodegeneration, it is important to identify an effective quantitative method to assess barrier integrity in animal models. In the present study, we developed and validated a quantitative method for assessing BBB and BSCB integrity using sodium fluorescein, a compound that outperformed other fluorescent dyes. We demonstrated using this method that multiple CNS regions progressively increase in permeability in models of Huntington’s disease and amyotrophic lateral sclerosis, while biphasic disruption occurred in a mouse model of Alzheimer’s disease with disease progression. Collectively, we report a quantitative fluorometric marker with validated reproducible experimental methods, that allows the effective assessment of BBB and BSCB integrity in animal models. This method could be useful to further the understanding of the contribution of these neuroprotective barriers to neurodegeneration processes.

C5a-C5aR1 Axis Activation Drives Envenomation Immunopathology by the Snake Naja annulifera

Publisher: Frontiers Media SA

Date: 15-04-2021

DOI: 10.3389/FIMMU.2021.652242

Abstract: Systemic complement activation drives a plethora of pathological conditions, but its role in snake envenoming remains obscure. Here, we explored complement’s contribution to the physiopathogenesis of Naja annulifera envenomation. We found that N. annulifera venom promoted the generation of C3a, C4a, C5a, and the soluble Terminal Complement Complex (sTCC) mediated by the action of snake venom metalloproteinases. N. annulifera venom also induced the release of lipid mediators and chemokines in a human whole-blood model. This release was complement-mediated, since C3/C3b and C5a Receptor 1 (C5aR1) inhibition mitigated the effects. In an experimental BALB/c mouse model of envenomation, N. annulifera venom promoted lipid mediator and chemokine production, neutrophil influx, and swelling at the injection site in a C5a-C5aR1 axis-dependent manner. N. annulifera venom induced systemic complementopathy and increased interleukin and chemokine production, leukocytosis, and acute lung injury (ALI). Inhibition of C5aR1 with the cyclic peptide antagonist PMX205 rescued mice from these systemic reactions and abrogated ALI development. These data reveal hitherto unrecognized roles for complement in envenomation physiopathogenesis, making complement an interesting therapeutic target in envenomation by N. annulifera and possibly by other snake venoms.

Acetate protects against intestinal ischemia-reperfusion injury independent of its cognate free fatty acid 2 receptor

Publisher: Wiley

Date: 17-06-2020

DOI: 10.1096/FJ.202000960R

Complement activation in the injured central nervous system: another dual-edged sword?

Publisher: Springer Science and Business Media LLC

Date: 21-06-2012

DOI: 10.1186/1742-2094-9-137

Abstract: The complement system, a major component of the innate immune system, is becoming increasingly recognised as a key participant in physiology and disease. The awareness that immunological mediators support various aspects of both normal central nervous system (CNS) function and pathology has led to a renaissance of complement research in neuroscience. Various studies have revealed particularly novel findings on the wide-ranging involvement of complement in neural development, synapse elimination and maturation of neural networks, as well as the progression of pathology in a range of chronic neurodegenerative disorders, and more recently, neurotraumatic events, where rapid disruption of neuronal homeostasis potently triggers complement activation. The purpose of this review is to summarise recent findings on complement activation and acquired brain or spinal cord injury, i.e. ischaemic-reperfusion injury or stroke, traumatic brain injury (TBI) and spinal cord injury (SCI), highlighting the potential for complement-targeted therapeutics to alleviate the devastating consequences of these neurological conditions.

Pharmacological inhibition of complement C5a-C5a1 receptor signalling ameliorates disease pathology in the hSOD1^G93A mouse model of amyotrophic lateral sclerosis

Publisher: Wiley

Date: 03-03-2017

DOI: 10.1111/BPH.13730

Therapeutic activity of a novel C5a receptor antagonist in inflammatory models of disease in rats

Publisher: University of Queensland Library

Date: 2003

DOI: 10.14264/106609

Should nueleotide sequence analyzing computer algorithms always extend homologies by extending homologies?

Publisher: Oxford University Press (OUP)

Date: 1986

DOI: 10.1093/NAR/14.1.425

Abstract: Most computer algorithms used for comparing or aligning nucleotide sequences rely on the premise that the best way to extend a homology between the two sequences is to select a match rather than a mismatch. We have tested this assumption and found that it is not always valid.

T helper 1 immunity requires complement-driven NLRP3 inflammasome activity in CD4 ⁺ T cells

Publisher: American Association for the Advancement of Science (AAAS)

Date: 17-06-2016

DOI: 10.1126/SCIENCE.AAD1210

Abstract: The classical view of immune activation is that innate immune cells, such as macrophages and dendritic cells, recognize invading microbes and then alert adaptive immune cells, such as T cells, to respond. Arbore et al. now show that innate and adaptive immunity converge in human and mouse T cells. Activated T cells express components of the complement cascade, which in turn leads to the assembly of NLRP3 inflammasomes—both critical components of innate immunity that help hosts detect and eliminate microbes. In T cells, complement and inflammasomes work together to push T cells to differentiate into a specialized subset of T cells important for eliminating intracellular bacteria. Science , this issue p. 10.1126/science.aad1210

Complement peptide receptors (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database

Publisher: Edinburgh University Library

Date: 16-09-2019

DOI: 10.2218/GTOPDB/F5/2019.4

Abstract: Complement peptide receptors (nomenclature as agreed by the NC-IUPHAR subcommittee on Complement peptide receptors [98]) are activated by the endogenous ~75 amino-acid anaphylatoxin polypeptides C3a and C5a, generated upon stimulation of the complement cascade. C3a and C5a exert their functions through binding to their receptors (C3aR and C5aR), causing cell activation and triggering cellular degranulation that contributes to the local inflammation.

SARS‐CoV‐2 triggers complement activation through interactions with heparan sulfate

Publisher: Wiley

Date: 2022

DOI: 10.1002/CTI2.1413

Abstract: To determine whether SARS‐CoV‐2 can trigger complement activation, the pathways that are involved and the functional significance of the resultant effect. SARS‐CoV‐2 was inoculated into a human lepirudin‐anticoagulated whole blood model, which contains a full repertoire of complement factors and leukocytes that express complement receptors. Complement activation was determined by measuring C5a production with an ELISA, and pretreatment with specific inhibitors was used to identify the pathways involved. The functional significance of this was then assessed by measuring markers of C5a signalling including leukocyte C5aR1 internalisation and CD11b upregulation with flow cytometry. SARS‐CoV‐2 inoculation in this whole blood model caused progressive C5a production over 24 h, which was significantly reduced by inhibitors for factor B, C3, C5 and heparan sulfate. However, this phenomenon could not be replicated in cell‐free plasma, highlighting the requirement for cell surface interactions with heparan sulfate. Functional analysis of this phenomenon revealed that C5aR1 signalling and CD11b upregulation in granulocytes and monocytes was delayed and only occurred after 24 h. SARS‐CoV‐2 is a noncanonical alternative pathway activator that progressively triggers complement activation through interactions with heparan sulfate.

Increased Placental Expression of Fibroblast Growth Factor 21 in Gestational Diabetes Mellitus

Publisher: The Endocrine Society

Date: 04-2014

DOI: 10.1210/JC.2013-2581

Abstract: Fibroblast growth factor 21 (FGF21) can regulate glucose and lipid metabolism. The placenta actively synthesizes and secretes many hormones, but it is unknown whether this includes FGF21. This study aimed to analyze the placental expression of FGF21 in women with or without gestational diabetes mellitus (GDM). FGF21 and peroxisome proliferator-activated receptor (PPAR)-α mRNA and protein expression were measured in the placentae of 20 women with and 18 without GDM. mRNA expression of PPARα, FGF receptors 1-4, the coreceptor β-klotho, and glucose transporter (GLUT)-1, -3, and -4 was investigated. Maternal and fetal circulating FGF21 levels were assessed in 10 mother-baby dyads per condition. FGF21 was expressed in the placenta and its mRNA expression increased in women with GDM [10.75 (interquartile range 3.28-125.6 AU)] vs control [0.83 (0.22-4.78), P < .001], as is its protein expression [GDM 2.89 (1.44-5.10)] vs control [0.42 (0.05-1.98), P < .05]. PPARα mRNA but not protein expression was increased in GDM [2.94 (0.70-7.26)] vs control [0.99 (0.43-2.17), P < .05] and was positively correlated to FGF21 mRNA expression (ρ = 0.43, P < .01). Placental mRNA expression of FGF receptors and GLUT1 was unchanged, and β-klotho, GLUT3, and GLUT4 showed increased expression in GDM. Maternal circulating FGF21 levels were similar [GDM 323 (75-921) vs control 269 (49-731) pg/mL, P = .81]. FGF21 was undetected in fetal cord blood. FGF21 is expressed in the placenta and its expression is increased in GDM. The absence of FGF21 in fetal cord blood suggests that neither placental FGF21 nor maternal circulating FGF21 is secreted into the fetal circulation. Placental FGF21 may be a regulator of placental metabolism.

Is the C3a receptor antagonist SB290157 a useful pharmacological tool?

Publisher: Wiley

Date: 18-10-2020

DOI: 10.1111/BPH.15264

THE CONCISE GUIDE TO PHARMACOLOGY 2017/18: Overview

Publisher: Wiley

Date: 21-10-2017

DOI: 10.1111/BPH.13882

The Learning Disabilities Network (LeaDNet): Using neurofibromatosis type 1 (NF1) as a paradigm for translational research

Publisher: Wiley

Date: 20-07-2012

DOI: 10.1002/AJMG.A.35535

Cholesterol Crystals Induce Coagulation Activation through Complement-Dependent Expression of Monocytic Tissue Factor

Publisher: The American Association of Immunologists

Date: 15-08-2019

DOI: 10.4049/JIMMUNOL.1900503

Abstract: Cholesterol crystals (CC) are strong activators of complement and could potentially be involved in thromboinflammation through complement–coagulation cross-talk. To explore the coagulation-inducing potential of CC, we performed studies in lepirudin-based human whole blood and plasma models. In addition, immunohistological examinations of brain thrombi and vulnerable plaque material from patients with advanced carotid atherosclerosis were performed using polarization filter reflected light microscopy to identify CC. In whole blood, CC exposure induced a time- and concentration-dependent generation of prothrombin fragment 1+2 (PTF1.2), tissue factor (TF) mRNA synthesis, and monocyte TF expression. Blocking Abs against TF abolished CC-mediated coagulation, thus indicating involvement of the TF-dependent pathway. Blockade of FXII by corn trypsin inhibitor had a significant inhibitory effect on CC-induced PTF1.2 in platelet-free plasma, although the overall activation potential was low. CC exposure did not induce platelet aggregation, TF microparticle induction, or TF on granulocytes or eosinophils. Inhibition of complement C3 by CP40 (compstatin), C5 by eculizumab, or C5aR1 by PMX53 blocked CC-induced PTF1.2 by 90% and reduced TF+ monocytes from 18–20 to 1–2%. The physiologic relevance was supported by birefringent CC structures adjacent to monocytes (CD14), TF, and activated complement iC3b and C5b–9 in a human brain thrombus. Furthermore, monocyte influx and TF induction in close proximity to CC-rich regions with activated complement were found in a vulnerable plaque. In conclusion, CC could be active, releasable contributors to thrombosis by inducing monocyte TF secondary to complement C5aR1 signaling.

Genomic diagnostics in polycystic kidney disease: an assessment of real-world use of whole-genome sequencing

Publisher: Springer Science and Business Media LLC

Date: 12-01-2021

DOI: 10.1038/S41431-020-00796-4

Supplementary Table 1 from Neutrophil Conversion to a Tumor-Killing Phenotype Underpins Effective Microbial Therapy

Publisher: American Association for Cancer Research (AACR)

Date: 14-04-2023

DOI: 10.1158/0008-5472.22633184.V1

Abstract: Characterization of neutrophil populations in single cell analysis.

Partial ligand-receptor engagement yields functional bias at the human complement receptor, C5aR1

Publisher: Cold Spring Harbor Laboratory

Date: 09-01-2019

DOI: 10.1101/515700

Abstract: The human complement component, C5a, binds two different seven transmembrane receptors termed as C5aR1 and C5aR2. C5aR1 is a prototypical G protein-coupled receptor that couples to Gαi sub-family of heterotrimeric G proteins and β-arrestins (βarr) following C5a stimulation. Peptide fragments derived from the carboxyl-terminus of C5a can still interact with the receptor, albeit with lower affinity, and can act as agonists or antagonists. However, whether such fragments might display ligand bias at C5aR1 remains unexplored. Here, we compare C5a and a modified C-terminal fragment of C5a, C5a pep , in terms of G protein coupling, βarr recruitment, endocytosis and ERK1/2 MAP kinase activation at the human C5aR1. We discover that C5a pep acts as a full-agonist for G protein coupling, while only displaying partial agonism for βarr recruitment. We also observe that whilst C5a pep is significantly less efficient in inducing C5aR1 endocytosis compared to C5a, it exhibits robust activation of ERK1/2 phosphorylation at levels similar to C5a. Interestingly, C5a pep displays full-agonist efficacy with respect to inhibiting LPS induced IL-6 secretion in human macrophages, but its ability to induce human neutrophil migration is substantially lower compared to C5a. Taken together, our findings reveal ligand-bias at C5aR1, not only with respect to transducer-coupling and receptor trafficking but also in terms of cellular responses. Our findings therefore establish a framework to explore additional levels of biased signaling and biased ligands at C5aR1 with therapeutic potential. More generally, our findings may be extended to discover biased ligands for the broad sub-family of chemokine GPCRs which also interact with chemokine ligands through a biphasic mechanism.

Application of CQI Tools to the Reduction in Risk of Needlestick Injury

Publisher: Cambridge University Press (CUP)

Date: 09-1995

DOI: 10.1086/647168

Abstract: To reduce the risk of needlestick injuries to laboratory workers. Continuous Quality Improvement (CQI) tools were applied to data collected on the number of blood gas syringes that arrived in the laboratory with needles still attached and to the reasons for these occurrences. A clinical chemistry department within a 900-bed tertiary referral university teaching hospital. Clinical chemistry laboratory staff and medical staff responsible for sending syringes with needles still attached. Changing to a preheparinized blood gas syringe that included a syringe cap within the packaging. Fivefold reduction in the number of syringes arriving in the laboratory with needles still attached. The risk of needlestick injury to laboratory workers can be reduced by provision to clinical staff of preheparinized blood gas syringes that include a syringe cap within the packaging. The techniques to CQI provide powerful tools for the identification, solving, and monitoring of safety-related issues within the healthcare environment.

The Ketone Body β-Hydroxybutyrate Does Not Inhibit Synuclein Mediated Inflammasome Activation in Microglia.

Publisher: Springer Science and Business Media LLC

Date: 23-08-2017

DOI: 10.1007/S11481-017-9754-5

Abstract: Parkinson's disease (PD) is recognized as the most common neurodegenerative movement disorder and results in debilitating motor deficits. The accumulation and spread of neurotoxic synuclein aggregates in the form of Lewy bodies is a key pathological feature of PD. Chronic activation of the NLRP3 inflammasome by protein aggregates is emerging as a major pathogenic mechanism in progressive neurodegenerative disorders and is considered an important therapeutic target. Recently the ketone body, β-hydroxy butyrate (BHB), was shown to efficiently inhibit the NLRP3 inflammasome in macrophages, and in vivo models of inflammatory disease. Furthermore, BHB can readily cross the blood brain barrier suggesting that it could have therapeutic benefits for the management of PD. In this study, we evaluated if BHB could inhibit chronic microglial inflammasome activation induced by pathological fibrillar synuclein aggregates. Interestingly, we found that BHB treatment almost completely blocked all aspects of inflammasome activation and pyroptosis induced by ATP and monosodium urate (MSU) crystals, consistent with previously published reports in macrophages. Surprisingly however, BHB did not inhibit inflammasome activation and release of IL-1β or caspase-1 induced by synuclein fibrils. Our results demonstrate that BHB does not block the upstream pathways regulating inflammasome activation by synuclein fibrils and suggest that synuclein mediated inflammasome activation proceeds via distinct mechanisms compared to traditional NLRP3 activators such as ATP and MSU.

Pharmacological characterisation of small molecule C5aR1 inhibitors in human cells reveals biased activities for signalling and function

Publisher: Elsevier BV

Date: 10-2020

DOI: 10.1016/J.BCP.2020.114156

SARS-CoV-2 Triggers Complement Activation through Interactions with Heparan Sulfate

Publisher: Cold Spring Harbor Laboratory

Date: 11-01-2022

DOI: 10.1101/2022.01.11.475820

Abstract: The complement system has been heavily implicated in severe COVID-19 with clinical studies revealing widespread gene induction, deposition, and activation. However, the mechanism by which complement is activated in this disease remains incompletely understood. Herein we examined the relationship between SARS-CoV-2 and complement by inoculating the virus in lepirudin-anticoagulated human blood. This caused progressive C5a production after 30 minutes and 24 hours, which was blocked entirely by inhibitors for factor B, C3, C5, and heparan sulfate. However, this phenomenon could not be replicated in cell-free plasma, highlighting the requirement for cell surface deposition of complement and interactions with heparan sulfate. Additional functional analysis revealed that complement-dependent granulocyte and monocyte activation was delayed. Indeed, C5aR1 internalisation and CD11b upregulation on these cells only occurred after 24 hours. Thus, SARS-CoV-2 is a non-canonical complement activator that triggers the alternative pathway through interactions with heparan sulfate.

Deep phenotyping detects a pathological CD4+ T-cell complosome signature in systemic sclerosis

Publisher: Springer Science and Business Media LLC

Date: 23-01-2020

DOI: 10.1038/S41423-019-0360-8

Monitoring C5aR2 Expression Using a Floxed tdTomato-C5aR2 Knock-In Mouse

Publisher: The American Association of Immunologists

Date: 11-2017

DOI: 10.4049/JIMMUNOL.1700710

Abstract: The biological significance of C5a receptor [(C5aR)2/C5L2], a seven-transmembrane receptor binding C5a and C5adesArg, remains ill-defined. Specific ligation of C5aR2 inhibits C5a-induced ERK1/2 activation, strengthening the view that C5aR2 regulates C5aR1-mediated effector functions. Although C5aR2 and C5aR1 are often coexpressed, a detailed picture of C5aR2 expression in murine cells and tissues is still lacking. To close this gap, we generated a floxed tandem dye (td)Tomato–C5aR2 knock-in mouse that we used to track C5aR2 expression in tissue-residing and circulating immune cells. We found the strongest C5aR2 expression in the brain, bone marrow, and airways. All myeloid-derived cells expressed C5aR2, although with different intensities. C5aR2 expression in blood and tissue neutrophils was strong and homogeneous. Specific ligation of C5aR2 in neutrophils from tdTomato–C5aR2 mice blocked C5a-driven ERK1/2 phosphorylation, demonstrating functionality of C5aR2 in the reporter mice. In contrast to neutrophils, we found tissue-specific differences in C5aR2 expression in eosinophils, macrophages, and dendritic cell subsets. Naive and activated T cells stained negative for C5aR2, whereas B cells from different tissues homogeneously expressed C5aR2. Also, NK cell subsets in blood and spleen strongly expressed C5aR2. Activation of C5aR2 in NK cells suppressed IL-12/IL-18–induced IFN-γ production. Intratracheal IL-33 challenge resulted in decreased C5aR2 expression in pulmonary eosinophils and monocyte-derived dendritic cells. In summary, we provide a detailed map of murine C5aR2 immune cell expression in different tissues under steady-state conditions and upon pulmonary inflammation. The C5aR2 knock-in mouse will help to reliably track and conditionally delete C5aR2 expression in experimental models of inflammation.

Complement receptor C3aR1 controls neutrophil mobilization following spinal cord injury through physiological antagonism of CXCR2

Publisher: American Society for Clinical Investigation

Date: 02-05-2019

DOI: 10.1172/JCI.INSIGHT.98254

The impact of reporting incidental findings from exome and whole-genome sequencing: Predicted frequencies based on modeling

Publisher: Elsevier BV

Date: 03-2015

DOI: 10.1038/GIM.2014.94

SARS-CoV-2 drives NLRP3 inflammasome activation in human microglia through spike-ACE2 receptor interaction

Publisher: Cold Spring Harbor Laboratory

Date: 12-01-2022

DOI: 10.1101/2022.01.11.475947

Abstract: Coronavirus disease-2019 (COVID-19) is primarily a respiratory disease, however, an increasing number of reports indicate that SARS-CoV-2 infection can also cause severe neurological manifestations, including precipitating cases of probable Parkinson’s disease. As microglial NLRP3 inflammasome activation is a major driver of neurodegeneration, here we interrogated whether SARS-CoV-2 can promote microglial NLRP3 inflammasome activation utilising a model of human monocyte-derived microglia. We identified that SARS-CoV-2 isolates can bind and enter microglia, triggering inflammasome activation in the absence of viral replication. Mechanistically, microglial NLRP3 could be both primed and activated with SARS-CoV-2 spike glycoprotein in a NF-κB and ACE2-dependent manner. Notably, virus- and spike protein-mediated inflammasome activation in microglia was significantly enhanced in the presence of α-synuclein fibrils, which was entirely ablated by NLRP3-inhibition. These results support a possible mechanism of microglia activation by SARS-CoV-2, which could explain the increased vulnerability to developing neurological symptoms akin to Parkinson’s disease in certain COVID-19 infected in iduals, and a potential therapeutic avenue for intervention. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) principally affects the lungs, however there is evidence that the virus can also reach the brain and lead to chronic neurological symptoms. In this study, we examined the interaction SARS-CoV-2 with brain immune cells, by using an ex-vivo model of human monocyte-derived microglia. We identified robust activation of the innate immune sensor complex, NLRP3 inflammasome, in cells exposed to SARS-CoV-2. This was dependent on spike protein-ACE2 receptor interaction and was potentiated in the presence of α-synuclein. We therefore identify a possible mechanism for SARS-CoV-2 and increased vulnerability to developing neurological dysfunction. These findings support a potential therapeutic avenue for treatment of SARS-CoV-2 driven neurological manifestations, through use of NLRP3 inflammasome or ACE2 inhibitors.

Protective effects of a potent C5a receptor antagonist on experimental acute limb ischemia-reperfusion in rats

Publisher: Elsevier BV

Date: 2004

DOI: 10.1016/J.JSS.2003.04.001

Abstract: The capacity of a potent C5a receptor antagonist to inhibit various parameters of local and remote organ injury following lower limb ischemia-reperfusion (I/R) in rats was investigated. Rats were subjected to 2 h bilateral hindlimb ischemia and 4 h reperfusion. Drug-treated rats received AcF-[OPdChaWR] (1 mg/kg) iv either 10 min before ischemia or 10 min prior to reperfusion, or orally (10 mg/kg) 30 min prior to ischemia. Levels of circulating creatine kinase (CK), lactate dehydrogenase (LDH), alanine and aspartate aminotransferase (ALT/AST), creatinine, blood urea nitrogen (BUN), polymorphonuclear leukocytes (PMNs), and calcium (Ca(++)) and potassium (K(+)) ions were determined. Other parameters measured included urinary protein levels, muscle edema, and myeloperoxidase (MPO) concentrations in the lung, liver, and muscle along with liver homogenate tumor necrosis factor-alpha (TNF-alpha) concentrations.L RESULTS: imb I/R injury was characterized by significant elevations of CK, LDH, ALT, AST, creatinine, BUN, proteinuria, PMNs, serum K(+), muscle edema, organ MPO, and liver homogenate TNF-alpha concentrations, but a significant reduction in serum Ca(2+) concentrations. When rats were treated with AcF-[OPdChaWR], there were significant improvements in all these parameters. These results indicate a pivotal role for C5a in inducing local and remote organ injury and suggest a possible new drug therapeutic category for preventing anticipated tissue injury associated with I/R.

THE CONCISE GUIDE TO PHARMACOLOGY 2019/20: G protein‐coupled receptors

Publisher: Wiley

Date: 11-11-2019

DOI: 10.1111/BPH.14748

Abstract: The Concise Guide to PHARMACOLOGY 2019/20 is the fourth in this series of biennial publications. The Concise Guide provides concise overviews of the key properties of nearly 1800 human drug targets with an emphasis on selective pharmacology (where available), plus links to the open access knowledgebase source of drug targets and their ligands ( www.guidetopharmacology.org ), which provides more detailed views of target and ligand properties. Although the Concise Guide represents approximately 400 pages, the material presented is substantially reduced compared to information and links presented on the website. It provides a permanent, citable, point‐in‐time record that will survive database updates. The full contents of this section can be found at oi/10.1111/bph.14748 . G protein‐coupled receptors are one of the six major pharmacological targets into which the Guide is ided, with the others being: ion channels, nuclear hormone receptors, catalytic receptors, enzymes and transporters. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. The landscape format of the Concise Guide is designed to facilitate comparison of related targets from material contemporary to mid‐2019, and supersedes data presented in the 2017/18, 2015/16 and 2013/14 Concise Guides and previous Guides to Receptors and Channels. It is produced in close conjunction with the International Union of Basic and Clinical Pharmacology Committee on Receptor Nomenclature and Drug Classification (NC‐IUPHAR), therefore, providing official IUPHAR classification and nomenclature for human drug targets, where appropriate.

Ashkenazi Jewish population screening for Tay-Sachs disease: The International and Australian experience

Publisher: Wiley

Date: 13-06-2015

DOI: 10.1111/JPC.12632

Abstract: Internationally, Tay-Sachs disease (TSD) preconception screening of Ashkenazi Jewish (AJ) in iduals and couples has led to effective primary prevention of TSD. In Australia, adolescent preconception genetic screening programs operate mainly in Jewish community high schools. These existing programs offer an effective means of primary prevention of TSD, are cost effective and safe. However, in the broader Australian community TSD screening is not systematically performed and cases still occur in unscreened AJ in iduals. In order to improve the effectiveness of Australian screening, there is a need for definitive guidelines for healthcare professionals to facilitate extension of the proven benefits of preconception TSD screening to all AJ in iduals at risk. We performed a systematic review of the relevant literature relating to AJ pre-conception and antenatal screening for TSD. The evidence was assessed using an established National Health and Medical Research Council evidence grading system. Evaluations of efficacy of TSD screening programs design and execution, cost-benefit and cost-utility health economic evaluation, and population outcomes were undertaken. The results have been used to propose a model for universal AJ TSD preconception and antenatal screening for the primary care setting.

Release of bioactive peptides from polyurethane films in vitro and in vivo: Effect of polymer composition

Publisher: Elsevier BV

Date: 09-2016

DOI: 10.1016/J.ACTBIO.2016.05.034

Abstract: Thermoplastic polyurethanes (TPUs) are widely used in biomedical applications due to their excellent biocompatibility. Their role as matrices for the delivery of small molecule therapeutics has been widely reported. However, very little is known about the release of bioactive peptides from this class of polymers. Here, we report the release of linear and cyclic peptides from TPUs with different hard and soft segments. Solvent casting of the TPU at room temperature mixed with the different peptides resulted in reproducible efflux profiles with no evidence of drug degradation. Peptide release was dependent on the size as well as the composition of the TPU. Tecoflex 80A (T80A) showed more extensive release than ElastEon 5-325, which correlated with a degree of hydration. It was also shown that the composition of the medium influenced the rate and extent of peptide efflux. Blending the different TPUs allowed for better control of peptide efflux, especially the initial burst effect. Peptide-loaded TPU prolonged the plasma levels of the anti-inflammatory cyclic peptide PMX53, which normally has a plasma half-life of less than 30min. Using a blend of T80A and E5-325, therapeutic plasma levels of PMX53 were observed up to 9days following a single intraperitoneal implantation of the drug-loaded film. PMX53 released from the blended TPUs significantly inhibited B16-F10 melanoma tumor growth in mice demonstrating its bioactivity in vivo. This study provides important findings for TPU-based therapeutic peptide delivery that could improve the pharmacological utility of peptides as therapeutics. Therapeutic peptides can be highly specific and potent pharmacological agents, but are poorly absorbed and rapidly degraded in the body. This can be overcome by using a matrix that protects the peptide in vivo and promotes its slow release so that a therapeutic effect can be achieved over days or weeks. Thermoplastic polyurethanes are a versatile family of polymers that are biocompatible and used for medical implants. Here, the release of several peptides from a range of polyurethanes was shown to depend on the type of polymer used in the polyurethane. This is the first study to examine polyurethane blends for peptide delivery and shows that the rate and extent of peptide release can be fine-tuned using different hard and soft segment mixtures in the polymer.

Complement peptide receptors in GtoPdb v.2023.1

Publisher: Edinburgh University Library

Date: 26-04-2023

DOI: 10.2218/GTOPDB/F5/2023.1

Abstract: Complement peptide receptors (nomenclature as agreed by the NC-IUPHAR subcommittee on Complement peptide receptors [113]) are activated by the endogenous ~75 amino-acid anaphylatoxin polypeptides C3a and C5a, generated upon stimulation of the complement cascade. C3a and C5a exert their functions through binding to their receptors (C3a receptor, C5a receptor 1 and C5a receptor 2), causing cell recruitment and triggering cellular degranulation that contributes to local inflammation.

Beyond the panel: preconception screening in consanguineous couples using the TruSight One “clinical exome”

Publisher: Elsevier BV

Date: 03-2019

DOI: 10.1038/S41436-018-0082-9

The Complement C3a Receptor Contributes to Melanoma Tumorigenesis by Inhibiting Neutrophil and CD4+ T Cell Responses.

Publisher: The American Association of Immunologists

Date: 06-2016

DOI: 10.4049/JIMMUNOL.1600210

Abstract: The complement peptide C3a is a key component of the innate immune system and a major fragment produced following complement activation. We used a murine model of melanoma (B16-F0) to identify a hitherto unknown role for C3a-C3aR signaling in promoting tumor growth. The results show that the development and growth of B16-F0 melanomas is retarded in mice lacking C3aR, whereas growth of established melanomas can be arrested by C3aR antagonism. Flow cytometric analysis showed alterations in tumor-infiltrating leukocytes in the absence of C3aR. Specifically, neutrophils and CD4(+) T lymphocyte subpopulations were increased, whereas macrophages were reduced. The central role of neutrophils was confirmed by depletion experiments that reversed the tumor inhibitory effects observed in C3aR-deficient mice and returned tumor-infiltrating CD4(+) T cells to control levels. Analysis of the tumor microenvironment showed upregulation of inflammatory genes that may contribute to the enhanced antitumor response observed in C3aR-deficient mice. C3aR deficiency/inhibition was also protective in murine models of BRAF(V600E) mutant melanoma and colon and breast cancer, suggesting a tumor-promoting role for C3aR signaling in a range of tumor types. We propose that C3aR activation alters the tumor inflammatory milieu, thereby promoting tumor growth. Therapeutic inhibition of C3aR may therefore be an effective means to trigger an antitumor response in melanoma and other cancers.

Monocyte CD14 and HLA-DR expression increases with disease duration and severity in amyotrophic lateral sclerosis

Publisher: Informa UK Limited

Date: 16-08-2021

DOI: 10.1080/21678421.2021.1964531

Prokineticin-2 upregulation during neuronal injury mediates a compensatory protective response against dopaminergic neuronal degeneration

Publisher: Springer Science and Business Media LLC

Date: 05-10-2016

DOI: 10.1038/NCOMMS12932

Abstract: Prokineticin-2 (PK2), a recently discovered secreted protein, regulates important physiological functions including olfactory biogenesis and circadian rhythms in the CNS. Interestingly, although PK2 expression is low in the nigral system, its receptors are constitutively expressed on nigrostriatal neurons. Herein, we demonstrate that PK2 expression is highly induced in nigral dopaminergic neurons during early stages of degeneration in multiple models of Parkinson’s disease (PD), including PK2 reporter mice and MitoPark mice. Functional studies demonstrate that PK2 promotes mitochondrial biogenesis and activates ERK and Akt survival signalling pathways, thereby driving neuroprotection. Importantly, PK2 overexpression is protective whereas PK2 receptor antagonism exacerbates dopaminergic degeneration in experimental PD. Furthermore, PK2 expression increased in surviving nigral dopaminergic neurons from PD brains, indicating that PK2 upregulation is clinically relevant to human PD. Collectively, our results identify a paradigm for compensatory neuroprotective PK2 signalling in nigral dopaminergic neurons that could have important therapeutic implications for PD.

Transdermal Pharmacology of Small Molecule Cyclic C5a Antagonists

Publisher: Springer US

Date: 2006

DOI: 10.1007/0-387-34134-X_22

Making national DNA databases safer [2]

Publisher: Elsevier BV

Date: 11-2003

DOI: 10.1016/S0140-6736(03)14861-1

C5a receptors C5aR1 and C5aR2 mediate opposing pathologies in a mouse model of melanoma

Publisher: Wiley

Date: 12-07-2019

DOI: 10.1096/FJ.201800980RR

Neuroinflammation as a therapeutic target in neurodegenerative diseases

Publisher: Elsevier

Date: 2017

DOI: 10.1016/B978-0-12-805120-7.00003-8

Developmental activities of the complement pathway in migrating neurons

Publisher: Springer Science and Business Media LLC

Date: 02-05-2017

DOI: 10.1038/NCOMMS15096

Abstract: In recent years the notion that malfunctioning of the immune system may result in developmental brain diseases has emerged. However, the role of immune molecules in the developing brain has not been well explored. The complement pathway converges to cleave C3. Here we show that key proteins in the lectin arm of this pathway, MASP1, MASP2 and C3, are expressed in the developing cortex and that neuronal migration is impaired in knockout and knockdown mice. Molecular mimics of C3 cleavage products rescue the migration defects that have been seen following knockdown of C3 or Masp2 . Pharmacological activation of the downstream receptors rescue Masp2 and C3 knockdown as well as C3 knockout. Therefore, we propose that the complement pathway is functionally important in migrating neurons of the developing cortex.

Complement alone drives efficacy of a chimeric antigonococcal monoclonal antibody

Publisher: Public Library of Science (PLoS)

Date: 19-06-2019

DOI: 10.1371/JOURNAL.PBIO.3000323

Specific inhibition of NLRP3 in chikungunya disease reveals a role for inflammasomes in alphavirus-induced inflammation

Publisher: Springer Science and Business Media LLC

Date: 28-08-2017

DOI: 10.1038/S41564-017-0015-4

Abstract: Mosquito-borne viruses can cause severe inflammatory diseases and there are limited therapeutic solutions targeted specifically at virus-induced inflammation. Chikungunya virus (CHIKV), a re-emerging alphavirus responsible for several outbreaks worldwide in the past decade, causes debilitating joint inflammation and severe pain. Here, we show that CHIKV infection activates the NLRP3 inflammasome in humans and mice. Peripheral blood mononuclear cells isolated from CHIKV-infected patients showed elevated NLRP3, caspase-1 and interleukin-18 messenger RNA expression and, using a mouse model of CHIKV infection, we found that high NLRP3 expression was associated with peak inflammatory symptoms. Inhibition of NLRP3 activation using the small-molecule inhibitor MCC950 resulted in reduced CHIKV-induced inflammation and abrogated osteoclastogenic bone loss and myositis, but did not affect in vivo viral replication. Mice treated with MCC950 displayed lower expression levels of the cytokines interleukin-6, chemokine ligand 2 and tumour necrosis factor in joint tissue. Interestingly, MCC950 treatment abrogated disease signs in mice infected with a related arthritogenic alphavirus, Ross River virus, but not in mice infected with West Nile virus-a flavivirus. Here, using mouse models of alphavirus-induced musculoskeletal disease, we demonstrate that NLRP3 inhibition in vivo can reduce inflammatory pathology and that further development of therapeutic solutions targeting inflammasome function could help treat arboviral diseases.

ISO compliant laboratory quality systems and incident monitoring improve the implementation of laboratory information systems

Publisher: Springer Science and Business Media LLC

Date: 06-2002

DOI: 10.1007/S00769-002-0480-0

A model for the mechanism and control of eukaryote gene splicing

Publisher: Elsevier BV

Date: 08-1982

DOI: 10.1016/0022-5193(82)90370-8

Placental lipase expression in pregnancies complicated by preeclampsia: a case–control study

Publisher: Springer Science and Business Media LLC

Date: 04-09-2015

DOI: 10.1186/S12958-015-0098-9

Chemical synthesis and characterisation of the complement C5 inhibitory peptide zilucoplan

Publisher: Springer Science and Business Media LLC

Date: 2021

DOI: 10.1007/S00726-020-02921-5

Neuroprotection in stroke by complement inhibition and immunoglobulin therapy

Publisher: Elsevier BV

Date: 02-2009

DOI: 10.1016/J.NEUROSCIENCE.2008.07.015

Role of complement C5a in mechanical inflammatory hypernociception: potential use of C5a receptor antagonists to control inflammatory pain

Publisher: Wiley

Date: 03-2008

DOI: 10.1038/SJ.BJP.0707640

Cost-effectiveness of a school-based Tay-Sachs and cystic fibrosis genetic carrier screening program

Publisher: Elsevier BV

Date: 09-2005

DOI: 10.1097/01.GIM.0000178496.91670.3B

Abstract: To explore the cost-effectiveness of school-based multi-disease genetic carrier screening. Decision analysis of the cost-effectiveness of a school-based Tay-Sachs disease and cystic fibrosis genetic carrier screening program, relative to no screening. Data relating to ethnicity profile, test-accepting behavior, and screening program cost were sourced from an existing program in Sydney, Australia. Compared to no screening, the incremental cost-effectiveness of the screening program is A dollar 5,834 per additional carrier detected. This cost-effectiveness ratio is most sensitive to changes in genetic test accuracy, and the cost of laboratory assays. The results imply a cost per affected birth avoided of approximately A dollar 530,000 (approximately US dollar 371,000). This preconceptional genetic carrier screening program offers comparable cost-effectiveness to prenatal screening programs for cystic fibrosis.

Therapeutic blockade of HMGB1 reduces early motor deficits, but not survival in the SOD1G93A mouse model of amyotrophic lateral sclerosis

Publisher: Springer Science and Business Media LLC

Date: 19-02-2019

DOI: 10.1186/S12974-019-1435-2

Carrier screening for Canavan disease in Australia

Publisher: Wiley

Date: 03-2004

DOI: 10.1023/B:BOLI.0000028837.63607.F0

Abstract: This study reports, for the first time, the carrier frequency of Canavan disease in the Ashkenazi Jewish population in Australia, and the identification of a novel mutation in the ASPA gene.

Contribution of the anaphylatoxin receptors, C3aR and C5aR, to the pathogenesis of pulmonary fibrosis

Publisher: Wiley

Date: 08-03-2016

DOI: 10.1096/FJ.201500044

An Immunoregulatory Role for Complement Receptors in Murine Models of Breast Cancer

Publisher: MDPI AG

Date: 08-01-2021

DOI: 10.3390/ANTIB10010002

Abstract: The complement system has demonstrated roles in regulating tumor growth, although these may differ between tumor types. The current study used two murine breast cancer models (EMT6 and 4T1) to investigate whether pharmacological targeting of receptors for complement proteins C3a (C3aR) and C5a (C5aR1) is protective in murine breast cancer models. In contrast to prior studies in other tumor models, treatment with the selective C5aR1 antagonist PMX53 had no effect on tumor growth. However, treatment of mice with a dual C3aR/C5aR1 agonist (YSFKPMPLaR) significantly slowed mammary tumor development and progression. Examination of receptor expression by quantitative polymerase chain reaction (qPCR) analysis showed very low levels of mRNA expression for either C3aR or C5aR1 by EMT6 or 4T1 mammary carcinoma cell lines compared with the J774 macrophage line or bone marrow-derived macrophages. Moreover, flow cytometric analysis found no evidence of C3aR or C5aR1 protein expression by either EMT6 or 4T1 cells, leading us to hypothesize that the tumor inhibitory effects of the dual agonist are indirect, possibly via regulation of the anti-tumor immune response. This hypothesis was supported by flow cytometric analysis of tumor infiltrating leukocyte populations, which demonstrated a significant increase in T lymphocytes in mice treated with the C3aR/C5aR1 agonist. These results support an immunoregulatory role for complement receptors in primary murine mammary carcinoma models. They also suggest that complement activation peptides can influence the anti-tumor response in different ways depending on the cancer type, the host immune response to the tumor and levels of endogenous complement activation within the tumor microenvironment.

Glucose clearance and uptake is increased in the SOD1^G93Amouse model of amyotrophic lateral sclerosis through an insulin‐independent mechanism

Publisher: Wiley

Date: 12-06-2021

DOI: 10.1096/FJ.202002450R

Valproic acid attenuates cellular senescence in diabetic kidney disease through the inhibition of complement C5a receptors.

Publisher: Springer Science and Business Media LLC

Date: 24-11-2022

DOI: 10.1038/S41598-022-24851-W

Abstract: Despite increasing knowledge about the factors involved in the progression of diabetic complications, diabetic kidney disease (DKD) continues to be a major health burden. Current therapies only slow but do not prevent the progression of DKD. Thus, there is an urgent need to develop novel therapy to halt the progression of DKD and improve disease prognosis. In our preclinical study where we administered a histone deacetylase (HDAC) inhibitor, valproic acid, to streptozotocin-induced diabetic mice, albuminuria and glomerulosclerosis were attenuated. Furthermore, we discovered that valproic acid attenuated diabetes-induced upregulation of complement C5a receptors, with a concomitant reduction in markers of cellular senescence and senescence-associated secretory phenotype. Interestingly, further examination of mice lacking the C5a receptor 1 (C5aR1) gene revealed that cellular senescence was attenuated in diabetes. Similar results were observed in diabetic mice treated with a C5aR1 inhibitor, PMX53. RNA-sequencing analyses showed that PMX53 significantly regulated genes associated with cell cycle pathways leading to cellular senescence. Collectively, these results for the first time demonstrated that complement C5a mediates cellular senescence in diabetic kidney disease. Cellular senescence has been implicated in the pathogenesis of diabetic kidney disease, thus therapies to inhibit cellular senescence such as complement inhibitors present as a novel therapeutic option to treat diabetic kidney disease.

Optimisation of a microfluidic method for the delivery of a small peptide

Publisher: MDPI AG

Date: 18-09-2021

DOI: 10.3390/PHARMACEUTICS13091505

Abstract: Peptides hold promise as therapeutics, as they have high bioactivity and specificity, good aqueous solubility, and low toxicity. However, they typically suffer from short circulation half-lives in the body. To address this issue, here, we have developed a method for encapsulation of an innate-immune targeted hexapeptide into nanoparticles using safe non-toxic FDA-approved materials. Peptide-loaded nanoparticles were formulated using a two-stage microfluidic chip. Microfluidic-related factors (i.e., flow rate, organic solvent, theoretical drug loading, PLGA type, and concentration) that may potentially influence the nanoparticle properties were systematically investigated using dynamic light scattering and transmission electron microscopy. The pharmacokinetic (PK) profile and biodistribution of the optimised nanoparticles were assessed in mice. Peptide-loaded lipid shell-PLGA core nanoparticles with designated size (~400 nm) and a sustained in vitro release profile were further characterized in vivo. In the form of nanoparticles, the elimination half-life of the encapsulated peptide was extended significantly compared with the peptide alone and resulted in a much higher distribution into the lung. These novel nanoparticles with lipid shells have considerable potential for increasing the circulation half-life and improving the biodistribution of therapeutic peptides to improve their clinical utility, including peptides aimed at treating lung-related diseases.

Glucose clearance and uptake is increased in the SOD1_G93Amouse model of amyotrophic lateral sclerosis through an insulin-independent mechanism

Publisher: Cold Spring Harbor Laboratory

Date: 03-08-2020

DOI: 10.1101/2020.08.02.233411

Abstract: Metabolic disturbances are associated with the progression of the neurodegenerative disorder, amyotrophic lateral sclerosis (ALS), however the molecular events that drive energy imbalances in ALS are not completely understood. In this study we aimed to elucidate deficits in energy homeostasis in the SOD1 G93A mouse model of ALS. We identified that SOD1 G93A mice at mid-symptomatic disease stage have increased oxygen consumption and faster exogenous glucose uptake, despite presenting with normal insulin tolerance. Fasting glucose homeostasis was also disturbed, along with increased liver glycogen stores, despite elevated circulating glucagon, suggesting that glucagon signalling is impaired. Metabolic gene expression profiling of livers indicated that glucose cannot be utilised efficiently in SOD1 G93A mice. Overall, we demonstrate that glucose homeostasis and uptake are altered in SOD1 G93A mice, which is linked to an increase in insulin-independent glucose uptake and a disturbance in glucagon sensitivity, suggesting glucagon secretion and signalling could be potential therapeutic targets for ALS.

C5L2: a controversial receptor of complement anaphylatoxin, C5a

Publisher: Wiley

Date: 13-12-2012

DOI: 10.1096/FJ.12-220509

Abstract: C5a is the paramount proinflammatory mediator of the complement cascade, and has been previously thought to act only through a single, G-protein-coupled, C5a receptor (C5aR also termed CD88). In 2000, a second C5a receptor, C5L2 (previously known as GPR77), was discovered yet, despite 12 yr of intensive research, its biological, or pathophysiological, function is both enigmatic and controversial. Unlike C5aR, this receptor does not couple to G proteins, and early studies promoted the hypothesis that C5L2 functions as a decoy receptor. However, recent data have provided other evidence for more complicated and conflicting interactions between C5L2 and other inflammatory mediators. C5L2 has been recently demonstrated to physically interact with both C5aR and β-arrestin to negatively regulate C5aR signaling toward an anti-inflammatory manner, and to reduce pathology, in several disease models in vivo. In direct contrast, other groups have demonstrated that C5L2 stimulation caused release of HMGB1 both in vitro and in vivo, and enhanced pathology in sepsis models, suggesting a clear proinflammatory signaling role. These astoundingly contradictory data challenge our precepts and complicate the foundational bases for the possible targeting of C5L2 as a therapeutic option in inflammatory disease. C5L2 may be the great masquerader in complement biology its function dependent on the cell type, species, and disease context. Because of these unusual and unforeseen complexities, we present the current state of knowledge on C5L2 structure, expression and, most controversially, its putative functions.-Li, R., Coulthard, L.G., Wu, M. C. L., Taylor, S. M., Woodruff, T. M. C5L2: a controversial receptor of complement anaphylatoxin, C5a.

EPHA4-FC treatment reduces ischemia/reperfusion-induced intestinal injury by inhibiting vascular permeability

Publisher: Ovid Technologies (Wolters Kluwer Health)

Date: 02-2016

DOI: 10.1097/SHK.0000000000000494

The maternal microbiome regulates infant respiratory disease susceptibility via intestinal Flt3L expression and plasmacytoid dendritic cell hematopoiesis

Publisher: Cold Spring Harbor Laboratory

Date: 06-01-2023

DOI: 10.1101/2023.01.05.522516

Abstract: Severe lower respiratory infection (sLRI) are a major cause of infant morbidity and mortality, and predispose to later chronic respiratory diseases such as asthma. Poor maternal diet during pregnancy is a risk factor for sLRI in the offspring. Here we demonstrate in mice that a maternal low-fibre diet (LFD) disrupts plasmacytoid and conventional dendritic cell (DC) hematopoiesis in the offspring, predisposing to sLRI and subsequent asthma. The LFD alters the composition of the maternal milk microbiome and assembling infant gut microbiome, ablating the induction of a developmental wave of the non-redundant DC growth factor Flt3L by neonatal intestinal epithelial cells. Therapy with a propionate-producing bacteria isolated from the milk of high-fibre diet-fed mothers, or supplementation with propionate, confers protection against sLRI by restoring gut Flt3L expression and pDC hematopoiesis. Our findings identify a microbiome-dependent Flt3L axis in the gut that regulates pDC hematopoiesis in early life and confers disease resistance.

Potential mechanisms to modify impaired glucose metabolism in neurodegenerative disorders

Publisher: SAGE Publications

Date: 24-10-2022

DOI: 10.1177/0271678X221135061

Abstract: Neurodegeneration refers to the selective and progressive loss-of-function and atrophy of neurons, and is present in disorders such as Alzheimer’s, Huntington’s, and Parkinson’s disease. Although each disease presents with a unique pattern of neurodegeneration, and subsequent disease phenotype, increasing evidence implicates alterations in energy usage as a shared and core feature in the onset and progression of these disorders. Indeed, disturbances in energy metabolism may contribute to the vulnerability of neurons to apoptosis. In this review we will outline these disturbances in glucose metabolism, and how fatty acids are able to compensate for this impairment in energy production in neurodegenerative disorders. We will also highlight underlying mechanisms that could contribute to these alterations in energy metabolism. A greater understanding of these metabolism-neurodegeneration processes could lead to improved treatment options for neurodegenerative disease patients.

Characterisation of small molecule ligands 4CMTB and 2CTAP as modulators of human FFA2 receptor signalling.

Publisher: Springer Science and Business Media LLC

Date: 13-12-2018

DOI: 10.1038/S41598-018-36242-1

Abstract: Short chain fatty acids (SCFAs) are protective against inflammatory diseases. Free fatty acid receptor 2 (FFA2), is a target of SCFAs however, their selectivity for FFA2 over other FFA receptors is limited. This study aimed to functionally characterise 2-(4-chlorophenyl)-3-methyl-N-(thiazole-2-yl)butanamide (4CMTB) and 4-((4-(2-chlorophenyl)thiazole-2-yl)amino)-4oxo-3-phenylbutanoic acid (2CTAP), and their enantiomers, in modulating FFA2 activity. The racemic mixture ( R/S ) and its constituents ( R-) and ( S- ) 4CMTB or 2CTAP were used to stimulate human (h)FFA2 in the absence or presence of acetate. Calcium ions (Ca 2+ ), phosphorylated extracellular signal-regulated kinase 1 and 2 (pERK1/2) and cyclic adenosine monophosphate (cAMP) were measured. R/S -4CMTB is a functionally selective ago-allosteric ligand that enhances Ca 2+ response to acetate. Both R/S -4CMTB and S -4CMTB are more potent activators of pERK1/2 and inhibitors of forskolin-induced cAMP than acetate. S -4CMTB increased neutrophil infiltration in intestinal ischemia reperfusion injury (IRI). 2CTAP inhibited constitutive Ca 2+ levels, antagonised acetate-induced pERK1/2 and prevented damage following IRI. This study characterises enantiomers of functionally selective ligands for FFA2 in cells stably expressing hFFA2. It highlights the novel roles of selective FFA2 enantiomers 4CMTB and 2CTAP on Ca 2+ , pERK1/2 and cAMP and their roles as allosteric modulators which, may assist in efforts to design novel therapeutic agents for FFA2-driven inflammatory diseases.

Nucleocapsid Specific Diagnostics for the Detection of Divergent SARS-CoV-2 Variants

Publisher: Frontiers Media SA

Date: 10-06-2022

DOI: 10.3389/FIMMU.2022.926262

Abstract: Since the start of the COVID-19 pandemic, multiple waves of SARS-CoV-2 variants have emerged. Of particular concern is the omicron variant, which harbors 28 mutations in the spike glycoprotein receptor binding and N-terminal domains relative to the ancestral strain. The high mutability of SARS-CoV-2 therefore poses significant hurdles for development of universal assays that rely on spike-specific immune detection. To address this, more conserved viral antigens need to be targeted. In this work, we comprehensively demonstrate the use of nucleocapsid (N)-specific detection across several assays using previously described nanobodies C2 and E2. We show that these nanobodies are highly sensitive and can detect ergent SARS-CoV-2 ancestral, delta and omicron variants across several assays. By comparison, spike-specific antibodies S309 and CR3022 only disparately detect SARS-CoV-2 variant targets. As such, we conclude that N-specific detection could provide a standardized universal target for detection of current and emerging SARS-CoV-2 variants of concern.

Neural tube defects, folate, and immune modulation

Publisher: Wiley

Date: 09-2013

DOI: 10.1002/BDRA.23177

The emerging role of complement in neuromuscular disorders

Publisher: Springer Science and Business Media LLC

Date: 27-10-2021

DOI: 10.1007/S00281-021-00895-4

Abstract: The complement cascade is a key arm of the immune system that protects the host from exogenous and endogenous toxic stimuli through its ability to potently regulate inflammation, phagocytosis, and cell lysis. Due to recent clinical trial successes and drug approvals for complement inhibitors, there is a resurgence in targeting complement as a therapeutic approach to prevent ongoing tissue destruction in several diseases. In particular, neuromuscular diseases are undergoing a recent focus, with demonstrated links between complement activation and disease pathology. This review aims to provide a comprehensive overview of complement activation and its role during the initiation and progression of neuromuscular disorders including myasthenia gravis, amyotrophic lateral sclerosis, and Duchenne muscular dystrophy. We will review the preclinical and clinical evidence for complement in these diseases, with an emphasis on the complement-targeting drugs in clinical trials for these indications.

TOLL-LIKE RECEPTORS IN ISCHEMIA-REPERFUSION INJURY

Publisher: Ovid Technologies (Wolters Kluwer Health)

Date: 07-2009

DOI: 10.1097/SHK.0B013E318193E333

The Complement C5a-C5aR1 GPCR Axis in COVID-19 Therapeutics

Publisher: Elsevier BV

Date: 11-2020

DOI: 10.1016/J.IT.2020.09.008

Species dependence for binding of small molecule agonist and antagonists to the C5a receptor on polymorphonuclear leukocytes

Publisher: Springer Science and Business Media LLC

Date: 2001

DOI: 10.1023/A:1011036414353

Abstract: This study investigated the receptor binding affinities of a C5a agonist and cyclic antagonists for polymorphonuclear leukocytes (PMNs) isolated from human, sheep, pig, dog, rabbit, guinea pig, rat and mouse. The affinities of the two small molecule antagonists, F-[OPdChaWR] and AcF-[OPdChaWR], and the agonist, YSFKPMPLaR, revealed large differences in C5a receptor (C5aR) affinities between species. The antagonists bound to human, rat and dog PMNs with similar high affinities, but with lower affinities to PMNs from all other species. The C5a agonist also bound with varying affinities between species, but showed a different affinity profile to the antagonists. In contrast, recombinant human C5a had similar affinity for PMNs of all species investigated. The low correlation between the affinities of the antagonists and the agonist between species either suggests that different receptor residues are important for distinguishing between agonist/antagonist binding, or that the agonist and antagonist peptides bind to two distinct sites within the C5aR.

Complement in Pregnancy: A Delicate Balance

Publisher: Wiley

Date: 27-08-2012

DOI: 10.1111/AJI.12000

Abstract: The complement system is a key component of innate host defence that, under normal conditions, is responsible for the opsonization and destruction of potential pathogens. However, inappropriate or excessive activation of complement can have a detrimental effect on the host and has been implicated in the pathophysiology of numerous disease states. Recently, there has been increasing evidence for a role of the complement system and, in particular, the potent pro-inflammatory anaphylatoxin complement component 5a (C5a) in both normal and complicated pregnancy. The following review describes the results of in vitro, animal, and human clinical studies investigating the role of the complement system in healthy pregnancy, recurrent miscarriage, preterm birth, and preecl sia.

The potential interplay between energy metabolism and innate complement activation in amyotrophic lateral sclerosis

Publisher: Wiley

Date: 19-04-2020

DOI: 10.1096/FJ.201901781

The Complement System Component C5a Produces Thermal Hyperalgesia via Macrophage-to-Nociceptor Signaling That Requires NGF and TRPV1

Publisher: Society for Neuroscience

Date: 04-05-2016

DOI: 10.1523/JNEUROSCI.3249-15.2016

Abstract: The complement cascade is a principal component of innate immunity. Recent studies have underscored the importance of C5a and other components of the complement system in inflammatory and neuropathic pain, although the underlying mechanisms are largely unknown. In particular, it is unclear how the complement system communicates with nociceptors and which ion channels and receptors are involved. Here we demonstrate that inflammatory thermal and mechanical hyperalgesia induced by complete Freund's adjuvant was accompanied by C5a upregulation and was markedly reduced by C5a receptor (C5aR1) knock-out or treatment with the C5aR1 antagonist PMX53. Direct administration of C5a into the mouse hindpaw produced strong thermal hyperalgesia, an effect that was absent in TRPV1 knock-out mice, and was blocked by the TRPV1 antagonist AMG9810. Immunohistochemistry of mouse plantar skin showed prominent expression of C5aR1 in macrophages. Additionally, C5a evoked strong Ca 2+ mobilization in macrophages. Macrophage depletion in transgenic macrophage Fas-induced apoptosis mice abolished C5a-dependent thermal hyperalgesia. Examination of inflammatory mediators following C5a injection revealed a rapid upregulation of NGF, a mediator known to sensitize TRPV1. Preinjection of an NGF-neutralizing antibody or Trk inhibitor GNF-5837 prevented C5a-induced thermal hyperalgesia. Notably, NGF-induced thermal hyperalgesia was unaffected by macrophage depletion. Collectively, these results suggest that complement fragment C5a induces thermal hyperalgesia by triggering macrophage-dependent signaling that involves mobilization of NGF and NGF-dependent sensitization of TRPV1. Our findings highlight the importance of macrophage-to-neuron signaling in pain processing and identify C5a, NGF, and TRPV1 as key players in this cross-cellular communication. SIGNIFICANCE STATEMENT This study provides mechanistic insight into how the complement system, a key component of innate immunity, regulates the development of pain hypersensitivity. We demonstrate a crucial role of the C5a receptor, C5aR1, in the development of inflammatory thermal and mechanical sensitization. By focusing on the mechanisms of C5a-induced thermal hyperalgesia, we show that this process requires recruitment of macrophages and initiation of macrophage-to-nociceptor signaling. At the molecular level, we demonstrate that this signaling depends on NGF and is mediated by the heat-sensitive nociceptive channel TRPV1. This deeper understanding of how immune cells and neurons interact to regulate pain processing is expected to facilitate mechanism-based approaches in the development of new analgesics.

Staphylococcus aureus‐induced complement activation promotes tissue factor‐mediated coagulation

Publisher: Elsevier BV

Date: 05-2018

DOI: 10.1111/JTH.13979

Abstract: Essentials Complement, Toll-like receptors and coagulation cross-talk in the process of thromboinflammation. This is explored in a unique human whole-blood model of S. aureus bacteremia. Coagulation is here shown as a downstream event of C5a-induced tissue factor (TF) production. Combined inhibition of C5 and CD14 efficiently attenuated TF and coagulation. Background There is extensive cross-talk between the complement system, the Toll-like receptors (TLRs), and hemostasis. Consumptive coagulopathy is a hallmark of sepsis, and is often mediated through increased tissue factor (TF) expression. Objectives To study the relative roles of complement, TLRs and TF in Staphylococcus aureus-induced coagulation. Methods Lepirudin-anticoagulated human whole blood was incubated with the three S. aureus strains Cowan, Wood, and Newman. C3 was inhibited with compstatin, C5 with eculizumab, C5a receptor 1 (C5aR1) and activated factor XII with peptide inhibitors, CD14, TLR2 and TF with neutralizing antibodies, and TLR4 with eritoran. Complement activation was measured by ELISA. Coagulation was measured according to prothrombin fragment 1 + 2 (PTF

Ectoparasite infestation patterns, haematology and serum biochemistry of urban-dwelling common brushtail possums

Publisher: Wiley

Date: 04-2026

DOI: 10.2981/WLB.00027

Abstract: Urban environments support high concentrations of humans, domestic pets and introduced animals, creating conditions conducive to the transmission of parasites. This study compared patterns of ectoparasite infestation of the common brushtail possum Trichosurus vulpecula in urbanised Sydney (n = 161) to those from a remote woodland site (n = 18) from February 2005 – November 2006. We found diff erences in ectoparasite species prevalence between the two groups: the flea Echidnophaga myrmecobii was only found on urban possums and the tick Ixodes trichosuri was much more prevalent in the urban habitat, while the mite Atellana papilio was more prevalent on woodland possums. E. myrmecobii and I. trichosuri diff ered from other ectoparasites by showing an association with host sex and host age. Potential physiological costs of ectoparasitism to urban‐dwelling possums were determined using multivariate analysis of haematology, serum biochemistry and body condition. Changes in serum iron levels were seen in the presence of both the tick Ixodes trichosuri and the flea E. myrmecobii , and E. myrmecobii was associated with elevated serum levels of the liver enzyme ALT. However, ectoparasite‐related changes in haematology and serum biochemistry were not indicative of long‐term pathology. In this urban possum population, the costs of ectoparasitism appear to be limited and unlikely to pose a major threat to the health of the population.

The C5a anaphylatoxin receptor CD88 is expressed in presynaptic terminals of hippocampal mossy fibres

Publisher: Springer Science and Business Media LLC

Date: 2009

DOI: 10.1186/1742-2094-6-34

Improving the quality of information on pathology request forms

Publisher: SAGE Publications

Date: 2004

DOI: 10.1258/000456304322664708

Abstract: Background: We have investigated the causes of incomplete pathology request forms received at our clinical chemistry laboratory. Based on a request form audit we found that the data most frequently missing from a pathology request form was the doctor's name, unique identification provider number, or signature. Methods: We examined the effect of issuing the requesting doctors with self-inking st s personalized with their name and a unique provider number. Results: The intervention led to an immediate and sustained improvement in compliance, with the proportion of incomplete forms falling from 43% to 2%. In contrast, distribution of a memorandum alone made no significant change to the number of pathology request forms with incomplete data arriving at the laboratory. Conclusion: This study describes a simple and low-cost solution to one of the causes of incomplete pathology request forms. It also demonstrates the effectiveness of systems improvement in health care.

C5a receptor 1 promotes autoimmunity, neutrophil dysfunction and injury in experimental anti-myeloperoxidase glomerulonephritis

Publisher: Elsevier BV

Date: 03-2018

DOI: 10.1016/J.KINT.2017.09.018

Abstract: The prospects for complement-targeted therapy in ANCA-associated vasculitis have been enhanced by a recent clinical trial in which C5a receptor 1 (C5aR1) inhibition safely replaced glucocorticoids in induction treatment. C5aR1 primes neutrophils for activation by anti-neutrophil cytoplasmic antibody (ANCA) and is therefore required in models of glomerulonephritis induced by anti-myeloperoxidase antibody. Although humoral and cellular autoimmunity play essential roles in ANCA-associated vasculitis, a role for C5aR1 in these responses has not been described. Here, we use murine models to dissect the role of C5aR1 in the generation of anti-myeloperoxidase autoimmunity and the effector responses resulting in renal injury. The genetic absence or pharmacological inhibition of C5aR1 results in reduced autoimmunity to myeloperoxidase with an attenuated Th1 response, increased Foxp3

Establishment and characterization of an optimized mouse model of multiple sclerosis-induced neuropathic pain using behavioral, pharmacologic, histologic and immunohistochemical methods

Publisher: Elsevier BV

Date: 11-2014

DOI: 10.1016/J.PBB.2014.09.003

Abstract: Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS) that causes debilitating central neuropathic pain in many patients. Although mouse models of experimental autoimmune encephalomyelitis (EAE) have provided insight on the pathobiology of MS-induced neuropathic pain, concurrent severe motor impairments confound quantitative assessment of pain behaviors over the disease course. To address this issue, we have established and characterized an optimized EAE-mouse model of MS-induced neuropathic pain. Briefly, C57BL/6 mice were immunized with MOG35-55 (200μg) and adjuvants comprising Quil A (45μg) and pertussis toxin (2×250ng). The traditionally used Freund's Complete Adjuvant (FCA) was replaced with Quil A, as FCA itself induces CNS neuroinflammation. Herein, EAE-mice exhibited a mild relapsing-remitting clinical disease course with temporal development of mechanical allodynia in the bilateral hindpaws. Mechanical allodynia was fully developed by 28-30days post-immunization (p.i.) and was maintained until study completion (52-60days p.i.), in the absence of confounding motor deficits. Single bolus doses of amitriptyline (1-7mg/kg), gabapentin (10-50mg/kg) and morphine (0.1-2mg/kg) evoked dose-dependent analgesia in the bilateral hindpaws of EAE-mice the corresponding ED50s were 1.5, 20 and 1mg/kg respectively. At day 39 p.i. in EAE-mice exhibiting mechanical allodynia in the hindpaws, there was marked demyelination and gliosis in the brain and lumbar spinal cord, mirroring these pathobiologic hallmark features of MS in humans. Our optimized EAE-mouse model of MS-associated neuropathic pain will be invaluable for future investigation of the pathobiology of MS-induced neuropathic pain and for efficacy profiling of novel molecules as potential new analgesics for improved relief of this condition.

Recent developments in C5/C5a inhibitors

Publisher: Informa UK Limited

Date: 24-03-2006

DOI: 10.1517/13543776.16.4.445

The Clinical Immunogenomics Research Consortium Australasia (CIRCA): a Distributed Network Model for Genomic Healthcare Delivery

Publisher: Springer Science and Business Media LLC

Date: 06-2020

DOI: 10.1007/S10875-020-00787-6

Increased Potency of a Novel Complement Factor 5a Receptor Antagonist in a Rat Model of Inflammatory Bowel Disease

Publisher: American Society for Pharmacology & Experimental Therapeutics (ASPET)

Date: 05-05-2005

DOI: 10.1124/JPET.105.086835

Abstract: We have previously shown that complement factor 5a (C5a) plays a role in the pathogenesis of 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats by using the selective, orally active C5a antagonist AcF-[OP(d-Cha)WR]. This study tested the efficacy and potency of a new C5a antagonist, hydrocinnamate (HC)-[OP(d-Cha)WR], which has limited intestinal lumenal metabolism, in this model of colitis. Analogs of AcF-[OP(d-Cha)WR] were examined for their susceptibility to alimentary metabolism in the rat using intestinal mucosal washings. One metabolically stable analog, HC-[OP(d-Cha)WR], was then evaluated pharmacokinetically and investigated at a range of doses (0.03-10 mg/kg/day p.o.) in the 8-day rat TNBS-colitis model, against the comparator drug AcF-[OP(d-Cha)WR]. Using various amino acid substitutions, it was determined that the AcF moiety of AcF-[OP(d-Cha)WR] was responsible for the metabolic instability of the compound in intestinal mucosal washings. The analog HC-[OP(d-Cha)WR], equiactive in vitro to AcF-[OP(d-Cha)WR], was resistant to intestinal metabolism, but it displayed similar oral bioavailability to AcF-[OP(d-Cha)WR]. However, in the rat TNBS-colitis model, HC-[OP(d-Cha)WR] was effective at reducing mortality, colon edema, colon macroscopic scores, and increasing food consumption and body weights, at 10- to 30-fold lower oral doses than AcF-[OP(d-Cha)WR]. These studies suggest that resistance to intestinal metabolism by HC-[OP(d-Cha)WR] may result in increased local concentrations of the drug in the colon, thus affording efficacy with markedly lower oral doses than AcF-[OP(d-Cha)WR] against TNBS-colitis. This large increase in potency and high efficacy of this compound makes it a potential candidate for clinical development against intestinal diseases such as inflammatory bowel disease.

Complement dysregulation in the central nervous system during development and disease

Publisher: Elsevier BV

Date: 10-2019

DOI: 10.1016/J.SMIM.2019.101340

Abstract: The complement cascade is an important arm of the immune system that plays a key role in protecting the central nervous system (CNS) from infection. Recently, it has also become clear that complement proteins have fundamental roles in the developing and aging CNS that are distinct from their roles in immunity. During neurodevelopment, complement signalling is involved in erse processes including neural tube closure, neural progenitor proliferation and differentiation, neuronal migration, and synaptic pruning. In acute neurotrauma and ischamic brain injury, complement drives inflammation and neuronal death, but also neuroprotection and regeneration. In diseases of the aging CNS including dementias and motor neuron disease, chronic complement activation is associated with glial activation, and synapse and neuron loss. Proper regulation of complement is thus essential to allow for an appropriately developed CNS and prevention of excessive damage following neurotrauma or during neurodegeneration. This review provides a comprehensive overview of the evidence for functional roles of complement in brain formation, and its dysregulation during acute and chronic disease. We also provide working models for how complement can lead to neurodevelopmental disorders such as schizophrenia and autism, and either protect, or propagate neurodegenerative diseases including Alzheimer's disease and amyotrophic lateral sclerosis.

The SEQANAL and SEQTALK programs: A new method of access to high-resolution nucleotide sequence comparison and analysis programs from a remote laboratory mini- or microcomputer

Publisher: Oxford University Press (OUP)

Date: 1985

DOI: 10.1093/BIOINFORMATICS/1.4.241

Abstract: A new method of access has been devised for biologists requiring the use of computer programs offering high-resolution analysis and comparison of nucleotide sequence data. The strategy involves the development of a pair of computer programs, called SEQANAL and SEQTALK, designed to operate in tandem. SEQANAL is a large and complex program intended to be used to discover regions of internal repeats and dyad symmetries within one sequence, or regions of homology, complementarity or optimal alignment between two sequences. Three algorithms are supported: those of Staden (1977, 1978) of Korn et al. (1977) Queen and Korn (1980) and the newly-described exhaustive tree-searching algorithm of Burnett et al. (1985, 1986). The SEQTALK program is a small, portable, interactive, front-end program with which the user can specify the instructions to control the SEQANAL program. Together, the SEQANAL and SEQTALK programs permit analyses to be performed at a remote facility on a mainframe computer under the complete control of a distant user equipped with minimal computing facilities, and without needing networking facilities.

Are serum cortisol levels a reliable indicator of wellbeing in the tammar wallaby, Macropus eugenii?

Publisher: Elsevier BV

Date: 07-2004

DOI: 10.1016/J.CBPB.2004.05.004

Intrinsic bias at non-canonical, β-arrestin-coupled seven transmembrane receptors

Publisher: Elsevier BV

Date: 11-2021

DOI: 10.1016/J.MOLCEL.2021.09.007

Synthetic Oligodeoxynucleotide CpG Motifs Activate Human Complement through Their Backbone Structure and Induce Complement-Dependent Cytokine Release

Publisher: The American Association of Immunologists

Date: 11-2022

DOI: 10.4049/JIMMUNOL.2101191

Abstract: Bacterial and mitochondrial DNA, sharing an evolutionary origin, act as danger-associated molecular patterns in infectious and sterile inflammation. They both contain immunomodulatory CpG motifs. Interactions between CpG motifs and the complement system are sparsely described, and mechanisms of complement activation by CpG remain unclear. Lepirudin-anticoagulated human whole blood and plasma were incubated with increasing concentrations of three classes of synthetic CpGs: CpG-A, -B, and -C oligodeoxynucleotides and their GpC sequence controls. Complement activation products were analyzed by immunoassays. Cytokine levels were determined via 27-plex beads-based immunoassay, and CpG interactions with in idual complement proteins were evaluated using magnetic beads coated with CpG-B. In whole blood and plasma, CpG-B and CpG-C (p & 0.05 for both), but not CpG-A (p & 0.8 for all), led to time- and dose-dependent increase of soluble C5b-9, the alternative complement convertase C3bBbP, and the C3 cleavage product C3bc. GpC-A, -B, and -C changed soluble fluid-phase C5b-9, C3bBbP, and C3bc to the same extent as CpG-A, -B, and -C, indicating a DNA backbone–dependent effect. Dose-dependent CpG-B binding was found to C1q (r = 0.83 p = 0.006) and factor H (r = 0.93 p & 0.001). The stimulatory complement effect was partly preserved in C2-deficient plasma and completely preserved in MASP-2–deficient serum. CpG-B increased levels of IL-1β, IL-2, IL-6, IL-8, MCP-1, and TNF in whole blood, which were completely abolished by inhibition of C5 and C5aR1 (p & 0.05 for all). In conclusion, synthetic analogs of bacterial and mitochondrial DNA activate the complement system via the DNA backbone. We suggest that CpG-B interacts directly with classical and alternative pathway components, resulting in complement-C5aR1–dependent cytokine release.

Serping1/C1 Inhibitor Affects Cortical Development in a Cell Autonomous and Non-cell Autonomous Manner

Publisher: Frontiers Media SA

Date: 16-06-2017

DOI: 10.3389/FNCEL.2017.00169

Deletion of Biliverdin Reductase A in Myeloid Cells Promotes Chemokine Expression and Chemotaxis in Part via a Complement C5a­–C5aR1 Pathway

Publisher: The American Association of Immunologists

Date: 15-05-2019

DOI: 10.4049/JIMMUNOL.1701443

Abstract: Biliverdin reductase (BVR)-A is a pleotropic enzyme converting biliverdin to bilirubin and a signaling molecule that has cytoprotective and immunomodulatory effects. We recently showed that biliverdin inhibits the expression of complement activation fragment 5a receptor one (C5aR1) in RAW 264.7 macrophages. In this study, we investigated the role of BVR-A in determining macrophage inflammatory phenotype and function via regulation of C5aR1. We assessed expression of C5aR1, M1-like macrophage markers, including chemokines (RANTES, IP-10), as well as chemotaxis in response to LPS and C5a in bone marrow–derived macrophages from BVRfl/fl and LysM-Cre:BVRfl/fl mice (conditional deletion of BVR-A in myeloid cells). In response to LPS, macrophages isolated from LysM-Cre:BVRfl/fl showed significantly elevated levels of C5aR1 as well as chemokines (RANTES, IP10) but not proinflammatory markers, such as iNOS and TNF. An increase in C5aR1 expression was also observed in peritoneal macrophages and several tissues from LysM-Cre:BVRfl/fl mice in a model of endotoxemia. In addition, knockdown of BVR-A resulted in enhanced macrophage chemotaxis toward C5a. Part of the effects of BVR-A deletion on chemotaxis and RANTES expression were blocked in the presence of a C5aR1 neutralizing Ab, confirming the role of C5a–C5aR1 signaling in mediating the effects of BVR. In summary, BVR-A plays an important role in regulating macrophage chemotaxis in response to C5a via modulation of C5aR1 expression. In addition, macrophages lacking BVR-A are characterized by the expression of M1 polarization–associated chemokines, the levels of which depend in part on C5aR1 signaling.

Senolytic therapy alleviates physiological human brain aging and COVID-19 neuropathology

Publisher: Research Square Platform LLC

Date: 16-03-2023

DOI: 10.21203/RS.3.RS-2675698/V1

Abstract: Aging is the primary risk factor for most neurodegenerative diseases, and recently coronavirus disease 2019 (COVID-19) has been associated with severe neurological manifestations that can eventually impact neurodegenerative conditions in the long-term. The progressive accumulation of senescent cells in vivo strongly contributes to brain aging and neurodegenerative co-morbidities but the impact of virus-induced senescence in the aetiology of neuropathologies is unknown. Here, we show that senescent cells accumulate in physiologically aged brain organoids of human origin and that senolytic treatment reduces inflammation and cellular senescence for which we found that combined treatment with the senolytic drugs dasatinib and quercetin rejuvenates transcriptomic human brain aging clocks. We further interrogated brain frontal cortex regions in postmortem patients who succumbed to severe COVID-19 and observed increased accumulation of senescent cells as compared to age-matched control brains from non-COVID-affected in iduals. Moreover, we show that exposure of human brain organoids to SARS-CoV-2 evoked cellular senescence, and that spatial transcriptomic sequencing of virus-induced senescent cells identified a unique SARS-CoV-2 variant-specific inflammatory signature that is different from endogenous naturally-emerging senescent cells. Importantly, following SARS-CoV-2 infection of human brain organoids, treatment with senolytics blocked viral retention and prevented the emergence of senescent corticothalamic and GABAergic neurons. Furthermore, we demonstrate in human ACE2 overexpressing mice that senolytic treatment ameliorates COVID-19 brain pathology following infection with SARS-CoV-2. In vivo treatment with senolytics improved SARS-CoV-2 clinical phenotype and survival, alleviated brain senescence and reactive astrogliosis, promoted survival of dopaminergic neurons, and reduced viral and senescence-associated secretory phenotype gene expression in the brain. Collectively, our findings demonstrate SARS-CoV-2 can trigger cellular senescence in the brain, and that senolytic therapy mitigates senescence-driven brain aging and multiple neuropathological sequelae caused by neurotropic viruses, including SARS-CoV-2.

Oral treatment with complement factor C5a receptor (CD88) antagonists inhibits experimental periodontitis in rats

Publisher: Wiley

Date: 03-07-2011

DOI: 10.1111/J.1600-0765.2011.01383.X

Abstract: The complement activation product 5a (C5a) is a potent mediator of the innate immune response to infection, and may thus also importantly determine the development of periodontitis. The present study was designed to explore the effect of several novel, potent and orally active C5a receptor (CD88) antagonists (C5aRAs) on the development of ligature-induced periodontitis in an animal model. Three different cyclic peptide C5aRAs, termed PMX205, PMX218 and PMX273, were investigated. Four groups of Wistar rats (n = 10 in each group) were used. Starting 3 d before induction of experimental periodontitis, rats either received one of the C5aRas (1-2 mg/kg) in the drinking water or received drinking water only. Periodontitis was assessed when the ligatures had been in place for 14 d. Compared with control rats, PMX205- and PMX218-treated rats had significantly reduced periodontal bone loss. The findings suggest that complement activation, and particularly C5a generation, may play a significant role in the development and progression of periodontitis. Blockade of the major C5a receptor, CD88, with specific inhibitors such as PMX205, may offer novel treatment options for periodontitis.

Response to Comment on “Inflammasome inhibition prevents α-synuclein pathology and dopaminergic neurodegeneration in mice”

Publisher: American Association for the Advancement of Science (AAAS)

Date: 17-05-2023

DOI: 10.1126/SCITRANSLMED.ADH0604

Abstract: We have replicated our original finding of elevated cleaved caspase-1 in mouse brains and neuroprotection by an NLRP3 inflammasome inhibitor in two mouse models of Parkinson’s disease.

Data from Neutrophil Conversion to a Tumor-Killing Phenotype Underpins Effective Microbial Therapy

Publisher: American Association for Cancer Research (AACR)

Date: 14-04-2023

DOI: 10.1158/0008-5472.C.6599657.V1

Abstract: Abstract The inflammatory microenvironment of solid tumors creates a protumorigenic milieu that resembles chronic inflammation akin to a subverted wound healing response. Here, we investigated the effect of converting the tumor microenvironment from a chronically inflamed state to one of acute microbial inflammation by injecting microbial bioparticles directly into tumors. Intratumoral microbial bioparticle injection led to rapid and dramatic changes in the tumor immune composition, the most striking of which was a substantial increase in the presence of activated neutrophils. i In situ /i photoconversion and intravital microscopy indicated that tumor neutrophils transiently switched from sessile producers of VEGF to highly motile neutrophils that clustered to make neutrophil-rich domains in the tumor. The neutrophil clusters remodeled tumor tissue and repressed tumor growth. Single-cell transcriptional analysis of microbe-stimulated neutrophils showed a profound shift in gene expression towards heightened activation and antimicrobial effector function. Microbe-activated neutrophils also upregulated chemokines known to regulate neutrophil and CD8 sup + /sup T-cell recruitment. Microbial therapy also boosted CD8 sup + /sup T-cell function and enhanced the therapeutic benefit of checkpoint inhibitor therapy in tumor-bearing mice and provided protection in a model of tumor recurrence. These data indicate that one of the major effector mechanisms of microbial therapy is the conversion of tumor neutrophils from a wound healing to an acutely activated cytotoxic phenotype, highlighting a rationale for broader deployment of microbial therapy in the treatment of solid cancers. Significance: Intratumoral injection of microbial bioparticles stimulates neutrophil antitumor functions, suggesting pathways for optimizing efficacy of microbial therapies and paving the way for their broader utilization in the clinic. /

Pharmacokinetics of a C5a receptor antagonist in the rat after different sites of enteral administration

Publisher: Elsevier BV

Date: 04-2008

DOI: 10.1016/J.EJPS.2008.01.009

Abstract: Pharmacokinetics of the orally active, cyclic peptide complement factor C5a receptor antagonist, AcF-[OP(D-Cha)WR] (PMX53) were determined in the rat. Biliary excretion of the unchanged drug was a major route of elimination after intravenous administration, but not following oral administration. Portal and peripheral blood levels of PMX53 were determined after oral administration or direct injection into the ileum, colon or local administration into the rectum. PMX53 was rapidly absorbed from mucosal sites, with peak plasma levels occurring as early as 5 min post-administration. Early portal blood levels were consistently higher than peripheral levels following ileal, colonic and rectal administration, but not after oral dosing. The results suggest that hepatic elimination occurs rapidly with higher (>or= 100 ng/ml) peripheral blood levels of the drug. Combination of PMX53 with the excipient chitosan resulted in significantly higher peripheral levels of the drug following ileal and colonic application, but not with buccal or oral administration. Buccal administration resulted in a similar plasma pharmacokinetic profile to oral administration. These results suggest that PMX53 is rapidly absorbed across mucosal membranes in the rat, and that administration using excipients such as chitosan may offer a method of increasing bioavailability.

The complement cascade in the regulation of neuroinflammation, nociceptive sensitization, and pain

Publisher: Elsevier BV

Date: 09-2021

DOI: 10.1016/J.JBC.2021.101085

Complement factor 5a as a therapeutic target

Publisher: Portico

Date: 2006

DOI: 10.1358/DOF.2006.031.04.980656

Sustained-release ketamine-loaded nanoparticles fabricated by sequential nanoprecipitation

Publisher: Elsevier BV

Date: 05-2020

DOI: 10.1016/J.IJPHARM.2020.119291

In Vivo Pharmacodynamic Method to Assess Complement C5a Receptor Antagonist Efficacy

Publisher: American Chemical Society (ACS)

Date: 21-12-2021

DOI: 10.1021/ACSPTSCI.1C00227

Generation of complement component C5a by ischemic neurons promotes neuronal apoptosis

Publisher: Wiley

Date: 31-05-2012

DOI: 10.1096/FJ.11-202382

Abstract: C5a receptors are found in the central nervous system (CNS), on both neurons and glia. However, the origin of the C5a, which activates these receptors, is unclear. In the present study, we show that primary cultured mouse cortical neurons constitutively express C5, the precursor of C5a, and express the classical receptor for C5a, CD88. With cell ischemia caused by 12 h glucose deprivation, or oxygen-glucose deprivation (OGD), neurons demonstrated increased apoptosis, up-regulation of CD88, and increased levels of C5a in the media. Exogenous murine C5a (100 nM) added to the neuronal cultures resulted in apoptosis, without affecting cell necrosis. Pretreatment of the cells with the specific CD88 receptor antagonist PMX53 (100 nM) significantly blocked ischemia-induced apoptosis (∼50%), and neurons from CD88(-/-) mice were similarly protected. In a murine model of stroke, using middle cerebral artery occlusion (MCAO), we found that C5a levels in the brain increased this also occurred in cerebral slice cultures exposed to OGD. CD88(-/-) mice subjected to MCAO had significantly reduced infarct volumes and improved neurological scores. Taken together, our results demonstrate that neurons in the CNS have the capability to generate C5a following ischemic stress, and this has the potential to activate their C5a receptors, with deleterious consequences.

Role of complement anaphylatoxin receptors in a mouse model of acute burn-induced pain

Publisher: Elsevier BV

Date: 02-2018

DOI: 10.1016/J.MOLIMM.2017.12.016

Abstract: The complement system is an essential component of the innate immune response. The anaphylatoxins C3a and C5a are key drivers of the complement system, acting through the receptors C3aR, C5aR1 and C5aR2 to regulate inflammation. While a role for C5a activation of C5aR1 in inflammatory and neuropathic pain has been established, the role of the complement system in burn-induced pain has not been investigated. To address this gap, we assessed the role of complement receptors C3aR, C5aR1 and C5aR2 in a mouse model of acute burn-induced pain. Superficial burn injury was induced in C57BL/6 mice by firm application of left hind paw plantar surface to a hot plate set at 52.5 °C for 25 s. Development of burn-induced mechanical allodynia, thermal allodynia, weight bearing changes and edema was assessed in C3aR

Complement C5a Regulates Prolabor Mediators in Human Placenta1

Publisher: Oxford University Press (OUP)

Date: 06-2012

DOI: 10.1095/BIOLREPROD.111.098475

Abstract: Human preterm and term parturition is associated with inflammatory cascades in the uteroplacental unit. Activation of the complement cascade releases potent proinflammatory mediators, including the anaphylatoxin C5a, which exerts its biological effects through its receptors, C5AR (also known as CD88) and C5L2, official symbol GPR77. To date, there are few data available on the role of C5a and CD88 in human pregnancy, so the aim of this study was to determine the effect of C5a and CD88 on some key inflammatory pathways involved in human parturition. Placental tissue s les were obtained from normal pregnancies at the time of Cesarean section. Human placental and fetal membranes were incubated in the absence (basal control) or presence of 0.5 μg/ml (~60 nM) human recombinant C5a for 24 h. Concentrations of proinflammatory cytokines, prostaglandins, and 8-isoprostane (a marker of oxidative stress) were quantified by ELISA and secretory matrix metalloproteinases (MMPs) activity by zymography. NFKB DNA binding activity and NFKBIA (IkappaB-alpha inhibitor of NFKB) protein degradation were analyzed by ELISA and Western blotting, respectively. In the presence of C5a, proinflammatory cytokines (IL6 and IL8), cyclooxygenase (COX)-2 official symbol PTGS2) expression, and subsequent prostaglandin (PGE(2) and PGF(2alpha)), MMP9 enzyme production, and NFKB DNA activation were all significantly increased. The C5a-induced prolabor responses were significantly reduced by treatment with the selective CD88 antagonist PMX53 and the NFKB inhibitor BAY 11-7082. We conclude that C5a upregulates prolabor mediators in human gestational tissues via CD88-mediated NFKB activation.

Properdin Provides Protection from Citrobacter rodentium–Induced Intestinal Inflammation in a C5a/IL-6–Dependent Manner

Publisher: The American Association of Immunologists

Date: 04-2015

DOI: 10.4049/JIMMUNOL.1401814

Abstract: Citrobacter rodentium is an attaching and effacing mouse pathogen that models enteropathogenic and enterohemorrhagic Escherichia coli in humans. The complement system is an important innate defense mechanism however, only scant information is available about the role of complement proteins during enteric infections. In this study, we examined the impact of the lack of properdin, a positive regulator of complement, in C. rodentium–induced colitis. Following infection, properdin knockout (PKO) mice had increased diarrhea and exacerbated inflammation combined with defective epithelial cell–derived IL-6 and greater numbers of colonizing bacteria. The defect in the mucosal response was reversed by administering exogenous properdin to PKO mice. Then, using in vitro and in vivo approaches, we show that the mechanism behind the exacerbated inflammation of PKO mice is due to a failure to increase local C5a levels. We show that C5a directly stimulates IL-6 production from colonic epithelial cells and that inhibiting C5a in infected wild-type mice resulted in defective epithelial IL-6 production and exacerbated inflammation. These outcomes position properdin early in the response to an infectious challenge in the colon, leading to complement activation and C5a, which in turn provides protection through IL-6 expression by the epithelium. Our results unveil a previously unappreciated mechanism of intestinal homeostasis involving complement, C5a, and IL-6 during bacteria-triggered epithelial injury.

Noninvasive assessment of altered activity following restraint in mice using an automated physiological monitoring system

Publisher: Informa UK Limited

Date: 02-01-2017

DOI: 10.1080/10253890.2016.1276898

Abstract: In the laboratory setting, typical endocrine and targeted behavioral tests are limited in their ability to provide a direct assessment of stress in animals housed in undisturbed conditions. We hypothesized that an automated phenotyping system would allow the detection of subtle stress-related behavioral changes well beyond the time-frames examined using conventional methods. In this study, we have utilized the TSE PhenoMaster system to continuously record basal behaviors and physiological parameters including activity, body weight, food intake and oxygen consumption in undisturbed and stressed C57Bl/6J male mice (n = 12/group), with a pharmacological intervention using the conventional anxiolytic, diazepam (5 mg kg

Sustained-release ketamine-loaded lipid-particulate system: in vivo assessment in mice

Publisher: Springer Science and Business Media LLC

Date: 20-11-2022

DOI: 10.1007/S13346-021-01093-3

Abstract: Ketamine is used as an analgesic adjuvant in patients with chronic cancer-related pain. However, ketamine's short half-life requires frequent dose administration. Our aim was to develop a sustained release formulation of ketamine with high loading and to evaluate the in vivo pharmacokinetics and biodistribution in mice. Here, ketamine hydrochloride sustained-release lipid particles (KSL) were developed using the thin-film hydration method. The mean (± SD) encapsulation efficiency (EE) and drug loading (DL) of KSL were 65.6 (± 1.7)% and 72.4 (± 0.5)% respectively, and the mean (± SD) size of the lipid particles and the polydispersity index were 738 (± 137) nm and 0.44 (± 0.02) respectively. The release period of KSL in pH 7.4 medium was 100% complete within 8 h in vitro but a sustained-release profile was observed for more than 5 days after intravenous injection in mice. Importantly, the KSL formulation resulted in a 27-fold increase in terminal half-life, a threefold increase in systemic exposure (AUC

Air Bubbles Activate Complement and Trigger Hemostasis and C3-Dependent Cytokine Release Ex Vivo in Human Whole Blood

Publisher: The American Association of Immunologists

Date: 12-2021

DOI: 10.4049/JIMMUNOL.2100308

Abstract: Venous air embolism, which may complicate medical and surgical procedures, activates complement and triggers thromboinflammation. In lepirudin-anticoagulated human whole blood, we examined the effect of air bubbles on complement and its role in thromboinflammation. Whole blood from 16 donors was incubated with air bubbles without or with inhibitors of C3, C5, C5aR1, or CD14. Complement activation, hemostasis, and cytokine release were measured using ELISA and quantitative PCR. Compared with no air, incubating blood with air bubbles increased, on average, C3a 6.5-fold, C3bc 6-fold, C3bBbP 3.7-fold, C5a 4.6-fold, terminal complement complex sC5b9 3.6-fold, prothrombin fragments 1+2 (PTF1+2) 25-fold, tissue factor mRNA (TF-mRNA) 26-fold, microparticle tissue factor 6.1-fold, β-thromboglobulin 26-fold (all p & 0.05), and 25 cytokines 11-fold (range, 1.5–78-fold all p & 0.0001). C3 inhibition attenuated complement and reduced PTF1+2 2-fold, TF-mRNA 5.4-fold, microparticle tissue factor 2-fold, and the 25 cytokines 2.7-fold (range, 1.4–4.9-fold all p & 0.05). C5 inhibition reduced PTF1+2 2-fold and TF-mRNA 12-fold (all p & 0.05). C5 or CD14 inhibition alone reduced three cytokines, including IL-1β (p = 0.02 and p = 0.03). Combined C3 and CD14 inhibition reduced all cytokines 3.9-fold (range, 1.3–9.5-fold p & 0.003) and was most pronounced for IL-1β (3.2- versus 6.4-fold), IL-6 (2.5- versus 9.3-fold), IL-8 (4.9- versus 8.6-fold), and IFN-γ (5- versus 9.5-fold). Antifoam activated complement and was avoided. PTF1+2 was generated in whole blood but not in plasma. In summary, air bubbles activated complement and triggered a C3-driven thromboinflammation. C3 inhibition reduced all mediators, whereas C5 inhibition reduced only TF-mRNA. Combined C5 and CD14 inhibition reduced IL-1β release. These data have implications for future mechanistic studies and possible pharmacological interventions in patients with air embolism.

Complementary relationship between repetitive sequences in the SV40 early gene pre-promoter enhancing region and big-T antigen splice junction exons

Publisher: Elsevier BV

Date: 10-1984

DOI: 10.1016/S0022-5193(84)80143-5

Abstract: Given that addiction has been characterized as a disorder of maladaptive learning and memory, one critical question is whether there are unique physical adaptations within neuronal ensembles that support addiction-related learned behavior. The search for the physical mechanisms of encoding these and other memories in the brain, often called the engram as a whole, continues despite decades of research. As we develop new technologies and tools that allow us to study cue- and behavior-activated Fos-expressing neuronal ensembles, the possibility of identifying the engrams of learning and memory is moving into the realm of reality rather than speculation. It has become clear from recent studies that there are specific functional, electrophysiological alterations unique to Fos-expressing ensemble neurons that may participate in encoding memories. The ultimate goal is to identify the addicted engram and reverse the physical changes that support this maladaptive form of learning.

Complement component 5a (C5a)

Publisher: Elsevier BV

Date: 11-2009

DOI: 10.1016/J.BIOCEL.2009.04.005

Abstract: The 74 amino acid glycoprotein, complement component 5a (C5a), is a potent pro-inflammatory mediator cleaved enzymatically from its precursor, C5, upon activation of the complement cascade. C5a is quickly metabolised by carboxypeptidases, forming the less potent C5adesArg. Acting via a classical G protein-coupled receptor, CD88, C5a and C5adesArg exert a number of effects essential to the innate immune response, while their actions at the more recently discovered non-G protein-coupled receptor, C5L2 (or GPR77), remain unclear. The widespread expression of C5a receptors throughout the body allows C5a to elicit a broad range of effects. Thus, C5a has been found to be a significant pathogenic driver in a number of immuno-inflammatory diseases, making C5a inhibition an attractive therapeutic strategy.

Complement C5a-C5aR1 signalling drives skeletal muscle macrophage recruitment in the hSOD1G93A mouse model of amyotrophic lateral sclerosis

Publisher: Springer Science and Business Media LLC

Date: 06-2017

DOI: 10.1186/S13395-017-0128-8

IFCC Position Paper: Report of the IFCC Taskforce on Ethics: Introduction and framework

Publisher: Walter de Gruyter GmbH

Date: 2007

DOI: 10.1515/CCLM.2007.199

Randomised controlled trial of recombinant human interferon ‐αA for chronic active hepatitis B

Publisher: Wiley

Date: 02-1990

DOI: 10.1111/J.1445-5994.1990.TB00362.X

Abstract: The efficacy of interferon treatment for Australian patients with chronic active hepatitis B (CAH-B) was assessed by a three-centre randomised controlled trial in Sydney and Brisbane. Thirty patients (29 with histologically-proven CAH-B with and without cirrhosis and one with chronic persistent hepatitis) were allocated to receive either thrice weekly intramuscular injections of recombinant human leucocyte interferon -alpha A (either 2.5, 5.0 or 10.0 million units/m2) for six months followed by 12 months of observation, or to be observed for 18 months without active treatment. Three of 23 treated patients but none of seven controls underwent clinical, biochemical and histological resolution of their disease with loss of HBsAg, HBeAg and HBV-DNA from serum. An additional six treated and two control patients underwent a sustained partial remission of their disease. This was characterised by resolution of symptoms and serum aminotransferase abnormalities in association with seroconversion from HBeAg positive to negative, loss of HBV-DNA from serum but persistent hepatitis B surface antigenaemia. In such patients, there was significant improvement in histological appearances but some necroinflammatory activity remained and fibrosis was unchanged. Although total response rates were similar in treated and control subjects, they appeared to occur earlier after interferon treatment. Treatment with interferon was associated with predictable but minor side effects that usually did not necessitate dose reduction and rarely compromised the patient's life style. Interferon is thus a feasible treatment for CAH-B. Complete responses occurred only in treated patients and partial responses appeared to occur earlier in treated than in untreated patients. However, differences in the partial response rate at 18 months were not significant and seroconversion from HBeAg positive to negative was not associated with complete histological resolution of disease activity. Hence, while interferon is a promising agent for treatment of CAH-B, efforts must continue to define more optimal treatment regimes and to identify those patients most likely to respond to this agent.

C5a induces caspase‐dependent apoptosis in brain vascular endothelial cells in experimental lupus

Publisher: Wiley

Date: 11-07-2016

DOI: 10.1111/IMM.12619

Development and validation of a LC-MS/MS assay for pharmacokinetic studies of complement C5a receptor antagonists PMX53 and PMX205 in mice

Publisher: Springer Science and Business Media LLC

Date: 25-05-2018

DOI: 10.1038/S41598-018-26387-4

Abstract: PMX53 and PMX205 are cyclic hexapeptide inhibitors of complement C5a receptors (C5aR1), that are widely used to study C5aR1 pathobiology in mouse models of disease. Despite their widespread use, limited information regarding their pharmacokinetics have been reported. Here, a bioanalytical method for the quantitative determination of PMX53 and PMX205 in plasma, brain and spinal cord of mice was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques. The LC-MS/MS method was validated in all three matrices according to regulatory guidelines and successfully applied to pharmacokinetic studies of PMX53 and PMX205 in C57BL/6 J mice following intravenous administration. The developed method was highly sensitive and sufficiently accurate with a lower limit of quantification within the range of 3–6 ng/ml in extracted plasma s les and 3–6 ng/g in processed tissue s les, which outperforms previously published LC-MS/MS methods. The results thus support the suitability, reliability, reproducibility and sensitivity of this validated technique. This method can therefore be applied to perform a complete pre-clinical investigation of PMX53 and PMX205 pharmacokinetics in mice.

TLQP-21 is a low potency partial C3aR activator on human primary macrophages

Publisher: Frontiers Media SA

Date: 26-01-2023

DOI: 10.3389/FIMMU.2023.1086673

Abstract: TLQP-21 is a 21-amino acid neuropeptide derived from the VGF precursor protein. TLQP-21 is expressed in the nervous system and neuroendocrine glands, and demonstrates pleiotropic roles including regulating metabolism, nociception and microglial functions. Several possible receptors for TLQP-21 have been identified, with complement C3a receptor (C3aR) being the most commonly reported. However, few studies have characterised the activity of TLQP-21 in immune cells, which represent the major cell type expressing C3aR. In this study, we therefore aimed to define the activity of both human and mouse TLQP-21 on cell signalling in primary human and mouse macrophages. We first confirmed that TLQP-21 induced ERK signalling in CHO cells overexpressing human C3aR, and did not activate human C5aR1 or C5aR2. TLQP-21 mediated ERK signalling was also observed in primary human macrophages. However, the potency for human TLQP-21 was 135,000-fold lower relative to C3a, and only reached 45% at the highest dose tested (10 μM). Unlike in humans, mouse TLQP-21 potently triggered ERK signalling in murine macrophages, reaching near full activation, but at ~10-fold reduced potency compared to C3a. We further confirmed the C3aR dependency of the TLQP-21 activities. Our results reveal significant discrepancy in TLQP-21 C3aR activity between human and murine receptors, with mouse TLQP-21 being consistently more potent than the human counterpart in both systems. Considering the supraphysiological concentrations of hTLQP-21 needed to only partially activate macrophages, it is likely that the actions of TLQP-21, at least in these immune cells, may not be mediated by C3aR in humans.

Development of Potent and Selective Agonists for Complement C5a Receptor 1 with in Vivo Activity

Publisher: American Chemical Society (ACS)

Date: 11-11-2021

DOI: 10.1021/ACS.JMEDCHEM.1C01174

Abstract: The anaphylatoxin C5a is a complement peptide associated with immune-related disorders. C5a binds with equal potency to two GPCRs, C5aR1 and C5aR2. Multiple C5a peptide agonists have been developed to interrogate the C5a receptor function but none show selectivity for C5aR1. To address these limitations, we developed potent and stable peptide C5aR1 agonists that display no C5aR2 activity and over 1000-fold selectivity for C5aR1 over C3aR. This includes BM213, which induces C5aR1-mediated calcium mobilization and pERK1/2 signaling but not β-arrestin recruitment, and BM221, which exhibits no signaling bias. Both ligands are functionally similar to C5a in human macrophage cytokine release assays and in a murine in vivo neutrophil mobilization assay. BM213 showed antitumor activity in a mouse model of mammary carcinoma. We anticipate that these C5aR1-selective agonists will be useful research tools to investigate C5aR1 function.

Unexpected Off-Target Activities for Recombinant C5a in Human Macrophages

Publisher: The American Association of Immunologists

Date: 2022

DOI: 10.4049/JIMMUNOL.2100444

Abstract: The anaphylatoxin C5a is core effector of complement activation. C5a exerts potent proinflammatory and immunomodulatory actions through interacting with its C5a receptors, C5aR1 and C5aR2, modulating multiple signaling and functional activities of immune cells. Native C5a contains a large N-linked glycosylation site at Asn64, which accounts for up to 25% of its m.w. To date, the vast majority of published studies examining C5a are performed using Escherichia coli–generated recombinant C5a, which is readily available from numerous commercial suppliers, but lacks this glycosylation moiety. However, a plasma-purified “native” form of C5a is also commercially available. The different size and glycosylation of these two C5a versions could have functional implications. Therefore, the current study aimed to compare recombinant human C5a to purified plasma-derived human C5a in driving the signaling and functional activities of human primary macrophages. We found that both versions of C5a displayed similar potencies at triggering C5aR1- and C5aR2-mediated cell signaling, but elicited distinct functional responses in primary human monocyte-derived macrophages. Multiple commercial sources of recombinant C5a, but not the plasma-purified or a synthetic C5a version, induced human monocyte-derived macrophages to produce IL-6 and IL-10 in a C5a receptor–independent manner, which was driven through Syk and NF-κB signaling and apparently not due to endotoxin contamination. Our results, therefore, offer caution against the sole use of recombinant human C5a, particularly in functional/cytokine assays conducted in human primary immune cells, and suggest studies using recombinant human C5a should be paired with C5aR1 inhibitors or purified/synthetic human C5a to confirm relevant findings.

Emerging Insights into the Structure and Function of Complement C5a Receptors

Publisher: Elsevier BV

Date: 08-2020

DOI: 10.1016/J.TIBS.2020.04.004

Bothrops jararaca Snake Venom Inflammation Induced in Human Whole Blood: Role of the Complement System

Publisher: Frontiers Media SA

Date: 02-06-2022

DOI: 10.3389/FIMMU.2022.885223

Abstract: The clinical manifestations of envenomation by Bothrops species are complex and characterized by prominent local effects that can progress to tissue loss, physical disability, or utation. Systemic signs can also occur, such as hemorrhage, coagulopathy, shock, and acute kidney failure. The rapid development of local clinical manifestations is accompanied by the presence of mediators of the inflammatory process originating from tissues damaged by the bothropic venom. Considering the important role that the complement system plays in the inflammatory response, in this study, we analyzed the action of Bothrops jararaca snake venom on the complement system and cell surface receptors involved in innate immunity using an ex vivo human whole blood model. B. jararaca venom was able to induce activation of the complement system in the human whole blood model and promoted a significant increase in the production of anaphylatoxins C3a/C3a-desArg, C4a/C4a-desArg, C5a/C5a-desArg and sTCC. In leukocytes, the venom of B. jararaca reduced the expression of CD11b, CD14 and C5aR1. Inhibition of the C3 component by Cp40, an inhibitor of C3, resulted in a reduction of C3a/C3a-desArg, C5a/C5a-desArg and sTCC to basal levels in s les stimulated with the venom. Exposure to B. jararaca venom induced the production of inflammatory cytokines and chemokines such as TNF-α, IL-8/CXCL8, MCP-1/CCL2 and MIG/CXCL9 in the human whole blood model. Treatment with Cp40 promoted a significant reduction in the production of TNF-α, IL-8/CXCL8 and MCP-1/CCL2. C5aR1 inhibition with PMX205 also promoted a reduction of TNF-α and IL-8/CXCL8 to basal levels in the s les stimulated with venom. In conclusion, the data presented here suggest that the activation of the complement system promoted by the venom of the snake B. jararaca in the human whole blood model significantly contributes to the inflammatory process. The control of several inflammatory parameters using Cp40, an inhibitor of the C3 component, and PMX205, a C5aR1 antagonist, indicates that complement inhibition may represent a potential therapeutic tool in B. jararaca envenoming.

A novel anticonvulsant mechanism via inhibition of complement receptor C5ar1 in murine epilepsy models

Publisher: Elsevier BV

Date: 04-2015

DOI: 10.1016/J.NBD.2015.02.004

Abstract: The role of complement system-mediated inflammation is of key interest in seizure and epilepsy pathophysiology, but its therapeutic potential has not yet been explored. We observed that the pro-inflammatory C5a receptor, C5ar1, is upregulated in two mouse models after status epilepticus the pilocarpine model and the intrahippoc al kainate model. The C5ar1 antagonist, PMX53, was used to assess potential anticonvulsant actions of blocking this receptor pathway. PMX53 was found to be anticonvulsant in several acute models (6Hz and corneal kindling) and one chronic seizure model (intrahippoc al kainate model). The effects in the 6Hz model were not found in C5ar1-deficient mice, or with an inactive PMX53 analogue suggesting that the anticonvulsant effect of PMX53 is C5ar1-specific. In the pilocarpine model, inhibition or absence of C5ar1 during status epilepticus lessened seizure power and protected hippoc al neurons from degeneration as well as halved SE-associated mortality. C5ar1-deficiency during pilocarpine-induced status epilepticus also was accompanied by attenuation of TNFα upregulation by microglia, suggesting that C5ar1 activation results in TNFα release contributing to disease. Patch cl studies showed that C5a-induced microglial K(+) outward currents were also inhibited with PMX53 providing a potential mechanism to explain acute anticonvulsant effects. In conclusion, our data indicate that C5ar1 activation plays a role in seizure initiation and severity, as well as neuronal degeneration following status epilepticus. The widespread anticonvulsant activity of PMX53 suggests that C5ar1 represents a novel target for improved anti-epileptic drug development which may be beneficial for pharmaco-resistant patients.

Suppl video 3 from Neutrophil Conversion to a Tumor-Killing Phenotype Underpins Effective Microbial Therapy

Publisher: American Association for Cancer Research (AACR)

Date: 14-04-2023

DOI: 10.1158/0008-5472.22633196.V1

Abstract: Neutrophils engage in multiple interactions with LLC tumor cells following microbial bioparticle treatment.

Processed foods drive intestinal barrier permeability and microvascular diseases

Publisher: American Association for the Advancement of Science (AAAS)

Date: 02-04-2021

DOI: 10.1126/SCIADV.ABE4841

Abstract: This study shows how highly processed foods can cause innate immune inflammation that promotes chronic microvascular disease.

Innate immune receptor C5aR1 regulates cancer cell fate and can be targeted to improve radiotherapy in tumours with immunosuppressive microenvironments

Publisher: Cold Spring Harbor Laboratory

Date: 10-01-2023

DOI: 10.1101/2023.01.10.521547

Abstract: An immunosuppressive microenvironment causes poor tumour T-cell infiltration and is associated with reduced patient overall survival in colorectal cancer. How to improve treatment responses in these tumours is still a challenge. Using an integrated screening approach to identify cancer-specific vulnerabilities, we identify complement receptor C5aR1 as a druggable target which when inhibited improves radiotherapy even in tumours displaying immunosuppressive features and poor CD8+ T-cell infiltration. While C5aR1 is well-known for its role in the immune compartment, we find that C5aR1 is also robustly expressed on malignant epithelial cells, highlighting potential tumour-cell specific functions. C5aR1 targeting results in increased NF-κB-dependent apoptosis specifically in tumours and not normal tissues indicating that in malignant cells, C5aR1 primarily regulates cell fate. Collectively, these data reveal that increased complement gene expression is part of the stress response mounted by irradiated tumours and that targeting C5aR1 can improve radiotherapy even in tumours displaying immunosuppressive features.

Comparative efficacy of a secretory phospholipase A2 inhibitor with conventional anti-inflammatory agents in a rat model of antigen-induced arthritis

Publisher: Springer Science and Business Media LLC

Date: 14-03-2011

DOI: 10.1186/AR3278

Improving radiotherapy in immunosuppressive microenvironments by targeting complement receptor C5aR1

Publisher: American Society for Clinical Investigation

Date: 12-10-2023

DOI: 10.1172/JCI168277

Loss of heterozygosity for the NF2 gene in retinal and optic nerve lesions of patients with neurofibromatosis 2

Publisher: Wiley

Date: 10-06-2002

DOI: 10.1002/PATH.1174

University Of New South Wales

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University Of Queensland

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University Of Sydney

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University Of New South Wales

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Royal North Shore Hospital

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Prince Of Wales Hospital

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Southern Cross University

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Garvan Institute Of Medical Research

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Invitae Corporation

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Genome.One

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Discovery Projects - Grant ID: DP0877848

Start Date: 2008

End Date: 12-2012

Amount: $240,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0883403

Start Date: 03-2010

End Date: 03-2013

Amount: $270,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0882898

Start Date: 2008

End Date: 07-2010

Amount: $221,180.00

Funder: Australian Research Council

ARC Future Fellowships - Grant ID: FT110100332

Start Date: 03-2012

End Date: 03-2016

Amount: $714,528.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP220103549

Start Date: 06-2022

End Date: 05-2025

Amount: $438,907.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE220100068

Start Date: 04-2022

End Date: 12-2023

Amount: $727,596.00

Funder: Australian Research Council