Ben Croker

Opposing roles of gp130-mediated STAT-3 and ERK-1/2 signaling in liver progenitor cell migration and proliferation

Publisher: Ovid Technologies (Wolters Kluwer Health)

Date: 2007

DOI: 10.1002/HEP.21535

Abstract: Gp130-mediated IL-6 signaling may play a role in oval cell proliferation in vivo. Levels of IL-6 are elevated in livers of mice treated with a choline-deficient ethionine-supplemented (CDE) diet that induces oval cells, and there is a reduction of oval cells in IL-6 knockout mice. The CDE diet recapitulates characteristics of chronic liver injury in humans. In this study, we determined the impact of IL-6 signaling on oval cell-mediated liver regeneration in vivo. Signaling pathways downstream of gp130 activation were also dissected. Numbers of A6(+ve) liver progenitor oval cells (LPCs) in CDE-treated murine liver were detected by immunohistochemistry and quantified. Levels of oval cell migration and proliferation were compared in CDE-treated mouse strains that depict models of gp130-mediated hyperactive ERK-1/2 signaling (gp130(deltaSTAT)), hyperactive STAT-3 signaling (gp130(Y757F) and Socs-3(-/deltaAlb)) or active ERK-1/2 as well as active STAT-3 signaling (wild-type). The A6(+ve) LPC numbers were increased with IL-6 treatment in vivo. The gp130(Y757F) mice displayed increased A6(+ve) LPCs numbers compared with wild-type and gp130(deltaSTAT) mice. Numbers of A6(+ve) LPCs were also increased in the livers of CDE treated Socs-3(-/deltaAlb) mice compared with their control counterparts. Lastly, inhibition of ERK-1/2 activation in cultured oval cells increased hyper IL-6-induced cell growth. For the first time, we have dissected the gp130-mediated signaling pathways, which influence liver progenitor oval cell proliferation. Hyperactive STAT-3 signaling results in enhanced oval cell numbers, whereas ERK-1/2 activation suppresses oval cell proliferation.

Multi-clonal SARS-CoV-2 neutralization by antibodies isolated from severe COVID-19 convalescent donors

Publisher: Public Library of Science (PLoS)

Date: 11-02-2021

DOI: 10.1371/JOURNAL.PPAT.1009165

Abstract: The interactions between antibodies, SARS-CoV-2 and immune cells contribute to the pathogenesis of COVID-19 and protective immunity. To understand the differences between antibody responses in mild versus severe cases of COVID-19, we analyzed the B cell responses in patients 1.5 months post SARS-CoV-2 infection. Severe, and not mild, infection correlated with high titers of IgG against Spike receptor binding domain (RBD) that were capable of ACE2:RBD inhibition. B cell receptor (BCR) sequencing revealed that VH3-53 was enriched during severe infection. Of the 22 antibodies cloned from two severe donors, six exhibited potent neutralization against authentic SARS-CoV-2, and inhibited syncytia formation. Using peptide libraries, competition ELISA and mutagenesis of RBD, we mapped the epitopes of the neutralizing antibodies (nAbs) to three different sites on the Spike. Finally, we used combinations of nAbs targeting different immune-sites to efficiently block SARS-CoV-2 infection. Analysis of 49 healthy BCR repertoires revealed that the nAbs germline VHJH precursors comprise up to 2.7% of all VHJHs. We demonstrate that severe COVID-19 is associated with unique BCR signatures and multi-clonal neutralizing responses that are relatively frequent in the population. Moreover, our data support the use of combination antibody therapy to prevent and treat COVID-19.

Genetic analysis of innate resistance to mouse cytomegalovirus (MCMV)

Publisher: Oxford University Press (OUP)

Date: 2005

DOI: 10.1093/BFGP/4.3.203

Abstract: Innate immunity is inherited and is, therefore, particularly susceptible to analysis by classical genetic methods. The 'phenotype first' approach has already revealed the principal receptors of the innate immune system as well as several essential signalling intermediates. It has recently emerged that innate resistance to mouse cytomegalovirus (MCMV) infection depends upon a large number of host genes with non-redundant functions hence, random germline mutagenesis frequently causes susceptibility to this pathogen. Approximately one in 30 pedigrees derived from N-ethyl-N-nitrosourea-mutagenised progenitors bears a recessive mutation that disrupts resistance to MCMV. Moreover, many of the genes required for resistance to MCMV will undoubtedly prove to have broad roles in immunity, creating resistance to many other microbes. The forward genetics approach offers an excellent opportunity to identify many of the key components of the innate immune system.

Cloning and characterization of the genes encoding the ankyrin repeat and SOCS box-containing proteins Asb-1, Asb-2, Asb-3 and Asb-4

Publisher: Elsevier BV

Date: 11-2000

DOI: 10.1016/S0378-1119(00)00402-9

Abstract: Members of the suppressor of cytokine signalling (SOCS) family of proteins have been shown to inhibit cytokine signalling via direct interactions with JAK kinases or activated cytokine receptors. In addition to their novel amino-terminal regions and SH2 domains that mediate these interactions, the SOCS proteins also contain carboxy-terminal regions of homology called the SOCS box. The SOCS box serves to couple SOCS proteins and their binding partners with the elongin B and C complex, possibly targeting them for degradation. Several other families of proteins also contain SOCS boxes but differ from the SOCS proteins in the type of domain or motif they contain upstream of the SOCS box. We report here the cloning, characterization, mapping and expression analysis of four members of the ankyrin repeat and SOCS box-containing (Asb) protein family.

Ptpn6 inhibits caspase-8- and Ripk3/Mlkl-dependent inflammation

Publisher: Springer Science and Business Media LLC

Date: 09-12-2019

DOI: 10.1038/S41590-019-0550-7

Interactions of SARS-CoV-2 envelope protein with amilorides correlate with antiviral activity

Publisher: Cold Spring Harbor Laboratory

Date: 06-04-2021

DOI: 10.1101/2021.04.06.438579

Abstract: SARS-CoV-2 is the novel coronavirus that is the causative agent of COVID-19, a sometimes-lethal respiratory infection responsible for a world-wide pandemic. The envelope (E) protein, one of four structural proteins encoded in the viral genome, is a 75-residue integral membrane protein whose transmembrane domain exhibits ion channel activity and whose cytoplasmic domain participates in protein-protein interactions. These activities contribute to several aspects of the viral replication-cycle, including virion assembly, budding, release, and pathogenesis. Here, we describe the structure and dynamics of full-length SARS-CoV-2 E protein in hexadecylphosphocholine micelles by NMR spectroscopy. We also characterized its interactions with four putative ion channel inhibitors. The chemical shift index and dipolar wave plots establish that E protein consists of a long transmembrane helix (residues 8-43) and a short cytoplasmic helix (residues 53-60) connected by a complex linker that exhibits some internal mobility. The conformations of the N-terminal transmembrane domain and the C-terminal cytoplasmic domain are unaffected by truncation from the intact protein. The chemical shift perturbations of E protein spectra induced by the addition of the inhibitors demonstrate that the N-terminal region (residues 6-18) is the principal binding site. The binding affinity of the inhibitors to E protein in micelles correlates with their antiviral potency in Vero E6 cells: HMA ≈ EIPA DMA Amiloride, suggesting that bulky hydrophobic groups in the 5’ position of the amiloride pyrazine ring play essential roles in binding to E protein and in antiviral activity. An N15A mutation increased the production of virus-like particles, induced significant chemical shift changes from residues in the inhibitor binding site, and abolished HMA binding, suggesting that Asn15 plays a key role in maintaining the protein conformation near the binding site. These studies provide the foundation for complete structure determination of E protein and for structure-based drug discovery targeting this protein. The novel coronavirus SARS-CoV-2, the causative agent of the world-wide pandemic of COVID-19, has become one of the greatest threats to human health. While rapid progress has been made in the development of vaccines, drug discovery has lagged, partly due to the lack of atomic-resolution structures of the free and drug-bound forms of the viral proteins. The SARS-CoV-2 envelope (E) protein, with its multiple activities that contribute to viral replication, is widely regarded as a potential target for COVID-19 treatment. As structural information is essential for drug discovery, we established an efficient s le preparation system for biochemical and structural studies of intact full-length SARS-CoV-2 E protein and characterized its structure and dynamics. We also characterized the interactions of amilorides with specific E protein residues and correlated this with their antiviral activity during viral replication. The binding affinity of the amilorides to E protein correlated with their antiviral potency, suggesting that E protein is indeed the likely target of their antiviral activity. We found that residue asparagine15 plays an important role in maintaining the conformation of the amiloride binding site, providing molecular guidance for the design of inhibitors targeting E protein.

RIPK1 regulates RIPK3-MLKL-driven systemic inflammation and emergency hematopoiesis

Publisher: Elsevier BV

Date: 05-2014

DOI: 10.1016/J.CELL.2014.04.019

Multi-Clonal Live SARS-CoV-2 In Vitro Neutralization by Antibodies Isolated from Severe COVID-19 Convalescent Donors

Publisher: Cold Spring Harbor Laboratory

Date: 06-10-2020

DOI: 10.1101/2020.10.06.323634

Abstract: The interactions between antibodies, SARS-CoV-2 and immune cells contribute to the pathogenesis of COVID-19 and protective immunity. To understand the differences between antibody responses in mild versus severe cases of COVID-19, we analyzed the B cell responses in patients 1.5 months post SARS-CoV-2 infection. Severe and not mild infection correlated with high titers of IgG against Spike receptor binding domain (RBD) that were capable of viral inhibition. B cell receptor (BCR) sequencing revealed two VH genes, VH3-38 and VH3-53, that were enriched during severe infection. Of the 22 antibodies cloned from two severe donors, six exhibited potent neutralization against live SARS-CoV-2, and inhibited syncytia formation. Using peptide libraries, competition ELISA and RBD mutagenesis, we mapped the epitopes of the neutralizing antibodies (nAbs) to three different sites on the Spike. Finally, we used combinations of nAbs targeting different immune-sites to efficiently block SARS-CoV-2 infection. Analysis of 49 healthy BCR repertoires revealed that the nAbs germline VHJH precursors comprise up to 2.7% of all VHJHs. We demonstrate that severe COVID-19 is associated with unique BCR signatures and multi-clonal neutralizing responses that are relatively frequent in the population. Moreover, our data support the use of combination antibody therapy to prevent and treat COVID-19.

Resident and Monocyte-Derived Dendritic Cells Become Dominant IL-12 Producers under Different Conditions and Signaling Pathways

Publisher: The American Association of Immunologists

Date: 15-08-2010

DOI: 10.4049/JIMMUNOL.0903793

Abstract: IL-12 is such a pivotal cytokine that it has been called the third signal for T cell activation, TCR engagement being the first and costimulation being the second. It has been generally viewed that the resident CD8+ dendritic cell (DC) subset is the predominant IL-12–producing cell type. In this study, we found, although this is so under steady state conditions, under inflammatory conditions monocyte-derived DC (mDC) became a major cell type producing IL-12. Depletion of either type of DC resulted in reduced production of IL-12 in vivo. For CD8+ DC, IL-12 production could be stimulated by various pathways viz. signaling through MyD88, Trif, or nucleotide-binding oligomerization domain (Nod)-like receptors. In contrast, for mDC, IL-12 production was mainly dependent on MyD88 signaling. Thus, conventional DCs and mDCs use different pathways to regulate IL-12 production.

Age-dependent regulation of SARS-CoV-2 cell entry genes and cell death programs correlates with COVID-19 severity

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

Date: 20-08-2021

DOI: 10.1126/SCIADV.ABF8609

Abstract: Changes in lung ACE2 expression and apoptotic priming throughout life span may affect COVID severity.

BID-ding on necroptosis in MDS

Publisher: American Society of Hematology

Date: 10-01-2019

DOI: 10.1182/BLOOD-2018-11-886242

Socs3 maintains the specificity of biological responses to cytokine signals during granulocyte and macrophage differentiation

Publisher: Elsevier BV

Date: 07-2008

DOI: 10.1016/J.EXPHEM.2008.02.008

Conformational flexibility in neutralization of SARS-CoV-2 by naturally elicited anti-SARS-CoV-2 antibodies

Publisher: Springer Science and Business Media LLC

Date: 05-08-2022

DOI: 10.1038/S42003-022-03739-5

Abstract: As new variants of SARS-CoV-2 continue to emerge, it is important to assess the cross-neutralizing capabilities of antibodies naturally elicited during wild type SARS-CoV-2 infection. In the present study, we evaluate the activity of nine anti-SARS-CoV-2 monoclonal antibodies (mAbs), previously isolated from convalescent donors infected with the Wuhan-Hu-1 strain, against the SARS-CoV-2 variants of concern (VOC) Alpha, Beta, Gamma, Delta and Omicron. By testing an array of mutated spike receptor binding domain (RBD) proteins, cell-expressed spike proteins from VOCs, and neutralization of SARS-CoV-2 VOCs as pseudoviruses, or as the authentic viruses in culture, we show that mAbs directed against the ACE2 binding site (ACE2bs) are more sensitive to viral evolution compared to anti-RBD non-ACE2bs mAbs, two of which retain their potency against all VOCs tested. At the second part of our study, we reveal the neutralization mechanisms at high molecular resolution of two anti-SARS-CoV-2 neutralizing mAbs by structural characterization. We solve the structures of the Delta-neutralizing ACE2bs mAb TAU-2303 with the SARS-CoV-2 spike trimer and RBD at 4.5 Å and 2.42 Å resolutions, respectively, revealing a similar mode of binding to that between the RBD and ACE2. Furthermore, we provide five additional structures (at resolutions of 4.7 Å, 7.3 Å, 6.4 Å, 3.3 Å, and 6.1 Å) of a second antibody, TAU-2212, complexed with the SARS-CoV-2 spike trimer. TAU-2212 binds an exclusively quaternary epitope, and exhibits a unique, flexible mode of neutralization that involves transitioning between five different conformations, with both arms of the antibody recruited for cross linking intra- and inter-spike RBD subunits. Our study provides additional mechanistic understanding about how antibodies neutralize SARS-CoV-2 and its emerging variants and provides insights on the likelihood of reinfections.

An Slfn2 mutation causes lymphoid and myeloid immunodeficiency due to loss of immune cell quiescence

Publisher: Springer Science and Business Media LLC

Date: 28-02-2010

DOI: 10.1038/NI.1847

SOCS regulation of the JAK/STAT signalling pathway

Publisher: Elsevier BV

Date: 08-2008

DOI: 10.1016/J.SEMCDB.2008.07.010

NOD1 mediates interleukin-18 processing in epithelial cells responding to Helicobacter pylori infection in mice

Publisher: Springer Science and Business Media LLC

Date: 26-06-2023

DOI: 10.1038/S41467-023-39487-1

Abstract: The interleukin-1 family members, IL-1β and IL-18, are processed into their biologically active forms by multi-protein complexes, known as inflammasomes. Although the inflammasome pathways that mediate IL-1β processing in myeloid cells have been defined, those involved in IL-18 processing, particularly in non-myeloid cells, are still not well understood. Here we report that the host defence molecule NOD1 regulates IL-18 processing in mouse epithelial cells in response to the mucosal pathogen, Helicobacter pylori . Specifically, NOD1 in epithelial cells mediates IL-18 processing and maturation via interactions with caspase-1, instead of the canonical inflammasome pathway involving RIPK2, NF-κB, NLRP3 and ASC. NOD1 activation and IL-18 then help maintain epithelial homoeostasis to mediate protection against pre-neoplastic changes induced by gastric H. pylori infection in vivo. Our findings thus demonstrate a function for NOD1 in epithelial cell production of bioactive IL-18 and protection against H. pylori -induced pathology.

Key Role of Suppressor of Cytokine Signaling 3 in Regulating gp130 Cytokine–Induced Signaling and Limiting Chondrocyte Responses During Murine Inflammatory Arthritis

Publisher: Wiley

Date: 26-08-2014

DOI: 10.1002/ART.38701

Abstract: To examine the impact of the gp130 cytokine family on murine articular cartilage and to explore a potential regulatory role of suppressor of cytokine signaling 3 (SOCS-3) in murine chondrocytes. In wild-type (WT) mouse chondrocytes, baseline receptor expression levels and gp130 cytokine-induced JAK/STAT signaling were determined by flow cytometry, and expression of SOCS-3 was assessed by quantitative polymerase chain reaction. The role of endogenous SOCS-3 was examined in cartilage explants and chondrocytes from mice with conditional deletion of Socs3 driven by the Col2a1 promoter in vitro (Socs3(Δ/Δcol2) ) and from mice during CD4+ T cell-dependent inflammatory monarthritis. Bone erosions in the murine joints were analyzed by micro-computed tomography. On chondrocytes from WT mice, gp130 and the oncostatin M (OSM) receptor were strongly expressed, whereas the transmembrane interleukin-6 (IL-6) receptor was expressed at much lower levels. Compared to other gp130 cytokines, OSM was the most potent activator of the JAK/STAT pathway and of SOCS-3 induction. Treatment of Socs3(Δ/Δcol2) mouse cartilage explants and chondrocytes with gp130 cytokines prolonged JAK/STAT signaling, enhanced cartilage degradation, increased the expression of Adamts4, Adamts5, and RANKL, and elevated the production of IL-6, granulocyte colony-stimulating factor, CXCL1, and CCL2. Socs3(Δ/Δcol2) mice developed exacerbated inflammation and joint damage in response to gp130 cytokine injections, and these histopathologic features were also observed in mice with inflammatory monarthritis. The results of this study highlight a key role for SOCS-3 in regulating chondrocyte responses during inflammatory arthritis. Within the gp130 cytokine family, OSM is a potent stimulus of chondrocyte responses, while IL-6 probably signals via trans-signaling. The gp130 cytokine-driven production of RANKL in chondrocytes may link chondrocyte activation and bone remodeling during inflammatory arthritis. Thus, these findings suggest that the inhibition of OSM might reduce the development and severity of structural joint damage during inflammatory arthritis.

β-glucan dependent shuttling of conidia from neutrophils to macrophages occurs during fungal infection establishment

Publisher: Cold Spring Harbor Laboratory

Date: 04-01-2019

DOI: 10.1101/512228

Abstract: The initial host response to fungal pathogen invasion is critical to infection establishment and outcome. However, the ersity of leukocyte-pathogen interactions is only recently being appreciated. We describe a new form of interleukocyte conidial exchange called “shuttling”. In Talaromyces marneffei and Aspergillus fumigatus zebrafish in vivo infections, live imaging demonstrated conidia initially phagocytosed by neutrophils were transferred to macrophages. Shuttling is unidirectional, not a chance event, involves alterations of phagocyte mobility, inter-cellular tethering, and phagosome transfer. Shuttling kinetics were fungal species-specific, implicating a fungal determinant. β-glucan serves as a fungal-derived signal sufficient for shuttling. Murine phagocytes also shuttled in vitro . The impact of shuttling for microbiological outcomes of in vivo infections is difficult to specifically assess experimentally, but for these two pathogens, shuttling augments initial conidial redistribution away from fungicidal neutrophils into the favourable macrophage intracellular niche. Shuttling is a frequent host athogen interaction contributing to fungal infection establishment patterns.

Rac2-deficient mice display perturbed T-cell distribution and chemotaxis, but only minor abnormalities in TH1 responses

Publisher: Wiley

Date: 06-2002

DOI: 10.1046/J.1440-1711.2002.01077.X

Abstract: The haematopoietic-specific RhoGTPase, Rac2, has been indirectly implicated in T-lymphocyte development and function, and as a pivotal regulator of T Helper 1 (T(H)1) responses. In other haematopoietic cells it regulates cytoskeletal rearrangement downstream of extracellular signals. Here we demonstrate that Rac2 deficiency results in an abnormal distribution of T lymphocytes in vivo and defects in T-lymphocyte migration and filamentous actin generation in response to chemoattractants in vitro. To investigate the requirement for Rac2 in IFN-gamma production and TH1 responses in vivo, Rac2-deficient mice were challenged with Leishmania major and immunized with ovalbumin-expressing cytomegalovirus. Despite a minor skewing towards a T(H)2 phenotype, Rac2-deficient mice displayed no increased susceptibility to L. major infection. Cytotoxic T-lymphocyte responses to cytomegalovirus and ovalbumin were also normal. Although Rac2 is required for normal T-lymphocyte migration, its role in the generation of T(H)1 responses to infection in vivo is largely redundant.

Optimism, Health-related Hardiness and Well-Being among Older Australian Women

Publisher: SAGE Publications

Date: 11-2004

DOI: 10.1177/1359105304045373

Abstract: This article examines whether optimism and health-related hardiness contribute to health and well-being among older women. Positive psychological characteristics, including optimism and health-related hardiness, are correlated with good self-rated health, but these variables are all affected by socioeconomic status, social support, physical illness and access to services. Using data from 9501 Australian women aged 73 to 78, we show that optimism and health-related hardiness explain a significant proportion of variance in all subscales of the SF-36, and in stress, even after these confounders are taken into account. The data, although cross-sectional, suggest that positive personal characteristics may contribute to well-being.

GENETIC ANALYSIS OF HOST RESISTANCE: Toll-Like Receptor Signaling and Immunity at Large

Publisher: Annual Reviews

Date: 04-2006

DOI: 10.1146/ANNUREV.IMMUNOL.24.021605.090552

Abstract: Classical genetic methods, driven by phenotype rather than hypotheses, generally permit the identification of all proteins that serve nonredundant functions in a defined biological process. Long before this goal is achieved, and sometimes at the very outset, genetics may cut to the heart of a biological puzzle. So it was in the field of mammalian innate immunity. The positional cloning of a spontaneous mutation that caused lipopolysaccharide resistance and susceptibility to Gram-negative infection led directly to the understanding that Toll-like receptors (TLRs) are essential sensors of microbial infection. Other mutations, induced by the random germ line mutagen ENU (N-ethyl-N-nitrosourea), have disclosed key molecules in the TLR signaling pathways and helped us to construct a reasonably sophisticated portrait of the afferent innate immune response. A still broader genetic screen—one that detects all mutations that compromise survival during infection—is permitting fresh insight into the number and types of proteins that mammals use to defend themselves against microbes.

Fas-mediated neutrophil apoptosis is accelerated by Bid, Bak, and Bax and inhibited by Bcl-2 and Mcl-1

Publisher: Proceedings of the National Academy of Sciences

Date: 18-07-2011

DOI: 10.1073/PNAS.1110358108

Abstract: During immune responses, neutrophils must integrate survival and death signals from multiple sources to regulate their lifespan. Signals that activate either the Bcl-2- or death receptor-regulated apoptosis pathways can provide powerful stimuli for neutrophils to undergo cell death, but whether they act cooperatively in parallel or directly cross-talk in neutrophils is not known. Previous studies suggested that Bcl-2 family proteins are not required for Fas-induced cell death in neutrophils, but did not examine whether they could modulate its rapid onset. By monitoring the rate of change in neutrophil viability associated with activation of the Fas-triggered death receptor pathway using real-time cell imaging, we show that the Bcl-2-related proteins Bid, Bax, and Bak accelerate neutrophil apoptosis but are not essential for cell death. Increased Bcl-2 or Mcl-1 expression prevents efficient induction of apoptosis by Fas stimulation indicating that the Bcl-2-regulated apoptosis pathway can directly interfere with Fas-triggered apoptosis. Fas has been shown to initiate NFκB activation and gene transcription in cell lines, however gene transcription is not altered in Fas-activated Bid −/− neutrophils, indicating that apoptosis occurs independently of gene transcription in neutrophils. The specification of kinetics of neutrophil apoptosis by Bid impacts on the magnitude of neutrophil IL-1β production, implicating a functional role for the Bcl-2-regulated pathway in controlling neutrophil responses to FasL. These data demonstrate that the intrinsic apoptosis pathway directly controls the kinetics of Fas-triggered apoptosis in neutrophils.

Neutrophil survival in the death zone

Publisher: American Society of Hematology

Date: 16-01-2014

DOI: 10.1182/BLOOD-2013-11-538298

Abstract: In this issue of Blood, Thompson et al reveal a key role for hypoxia-inducible factor (HIF)-2a in the adaptation of neutrophils to hypoxia. Tissue hypoxia is a common feature of trauma and inflammation. Infiltrating neutrophils must adapt to this low-oxygen environment to satisfy the metabolic and functional demands of an immune response.

Interactions of SARS-CoV-2 envelope protein with amilorides correlate with antiviral activity

Publisher: Public Library of Science (PLoS)

Date: 18-05-2021

DOI: 10.1371/JOURNAL.PPAT.1009519

Abstract: SARS-CoV-2 is the novel coronavirus that is the causative agent of COVID-19, a sometimes-lethal respiratory infection responsible for a world-wide pandemic. The envelope (E) protein, one of four structural proteins encoded in the viral genome, is a 75-residue integral membrane protein whose transmembrane domain exhibits ion channel activity and whose cytoplasmic domain participates in protein-protein interactions. These activities contribute to several aspects of the viral replication-cycle, including virion assembly, budding, release, and pathogenesis. Here, we describe the structure and dynamics of full-length SARS-CoV-2 E protein in hexadecylphosphocholine micelles by NMR spectroscopy. We also characterized its interactions with four putative ion channel inhibitors. The chemical shift index and dipolar wave plots establish that E protein consists of a long transmembrane helix (residues 8–43) and a short cytoplasmic helix (residues 53–60) connected by a complex linker that exhibits some internal mobility. The conformations of the N-terminal transmembrane domain and the C-terminal cytoplasmic domain are unaffected by truncation from the intact protein. The chemical shift perturbations of E protein spectra induced by the addition of the inhibitors demonstrate that the N-terminal region (residues 6–18) is the principal binding site. The binding affinity of the inhibitors to E protein in micelles correlates with their antiviral potency in Vero E6 cells: HMA ≈ EIPA DMA Amiloride, suggesting that bulky hydrophobic groups in the 5’ position of the amiloride pyrazine ring play essential roles in binding to E protein and in antiviral activity. An N15A mutation increased the production of virus-like particles, induced significant chemical shift changes from residues in the inhibitor binding site, and abolished HMA binding, suggesting that Asn15 plays a key role in maintaining the protein conformation near the binding site. These studies provide the foundation for complete structure determination of E protein and for structure-based drug discovery targeting this protein.

The role of neutrophils during mild and severe influenza virus infections of mice

Publisher: Public Library of Science (PLoS)

Date: 14-03-2011

DOI: 10.1371/JOURNAL.PONE.0017618

ATP-sensitive potassium channels mediate survival during infection in mammals and insects

Publisher: Springer Science and Business Media LLC

Date: 18-11-2007

DOI: 10.1038/NG.2007.25

Abstract: Specific homeostatic mechanisms confer stability in innate immune responses, preventing injury or death from infection. Here we identify, from a screen of N-ethyl-N-nitrosourea-mutagenized mice, a mutation causing both profound susceptibility to infection by mouse cytomegalovirus and approximately 20,000-fold sensitization to lipopolysaccharide (LPS), poly(I.C) and immunostimulatory (CpG) DNA. The LPS hypersensitivity phenotype is not suppressed by mutations in Myd88, Trif, Tnf, Tnfrsf1a, Ifnb, Ifng or Stat1, genes contributing to LPS responses, and results from an abnormality extrinsic to hematopoietic cells. The phenotype is due to a null allele of Kcnj8, encoding Kir6.1, a protein that combines with SUR2 to form an ATP-sensitive potassium channel (K(ATP)) expressed in coronary artery smooth muscle and endothelial cells. In Drosophila melanogaster, suppression of dSUR by RNA interference similarly causes hypersensitivity to infection by flock house virus. Thus, K(ATP) evolved to serve a homeostatic function during infection, and in mammals it prevents coronary artery vasoconstriction induced by cytokines dependent on TLR and/or MDA5 immunoreceptors.

ENU-induced phenovariance in mice: inferences from 587 mutations

Publisher: Springer Science and Business Media LLC

Date: 24-10-2012

DOI: 10.1186/1756-0500-5-577

Abstract: We present a compendium of N -ethyl- N -nitrosourea (ENU)-induced mouse mutations, identified in our laboratory over a period of 10 years either on the basis of phenotype or whole genome and/or whole exome sequencing, and archived in the Mutagenetix database. Our purpose is threefold: 1) to formally describe many point mutations, including those that were not previously disclosed in peer-reviewed publications 2) to assess the characteristics of these mutations and 3) to estimate the likelihood that a missense mutation induced by ENU will create a detectable phenotype. In the context of an ENU mutagenesis program for C57BL/6J mice, a total of 185 phenotypes were tracked to mutations in 129 genes. In addition, 402 incidental mutations were identified and predicted to affect 390 genes. As previously reported, ENU shows strand asymmetry in its induction of mutations, particularly favoring T to A rather than A to T in the sense strand of coding regions and splice junctions. Some amino acid substitutions are far more likely to be damaging than others, and some are far more likely to be observed. Indeed, from among a total of 494 non-synonymous coding mutations, ENU was observed to create only 114 of the 182 possible amino acid substitutions that single base changes can achieve. Based on differences in overt null allele frequencies observed in phenotypic vs. non-phenotypic mutation sets, we infer that ENU-induced missense mutations create detectable phenotype only about 1 in 4.7 times. While the remaining mutations may not be functionally neutral, they are, on average, beneath the limits of detection of the phenotypic assays we applied. Collectively, these mutations add to our understanding of the chemical specificity of ENU, the types of amino acid substitutions it creates, and its efficiency in causing phenovariance. Our data support the validity of computational algorithms for the prediction of damage caused by amino acid substitutions, and may lead to refined predictions as to whether specific amino acid changes are responsible for observed phenotypes. These data form the basis for closer in silico estimations of the number of genes mutated to a state of phenovariance by ENU within a population of G3 mice.

IL-6 promotes acute and chronic inflammatory disease in the absence of SOCS3.

Publisher: Wiley

Date: 26-04-2012

DOI: 10.1038/ICB.2011.29

Mutations in topoisomerase IIβ result in a B cell immunodeficiency.

Publisher: Springer Science and Business Media LLC

Date: 13-08-2019

DOI: 10.1038/S41467-019-11570-6

Abstract: B cell development is a highly regulated process involving multiple differentiation steps, yet many details regarding this pathway remain unknown. Sequencing of patients with B cell-restricted immunodeficiency reveals autosomal dominant mutations in TOP2B . TOP2B encodes a type II topoisomerase, an essential gene required to alleviate topological stress during DNA replication and gene transcription, with no previously known role in B cell development. We use Saccharomyces cerevisiae , and knockin and knockout murine models, to demonstrate that patient mutations in TOP2B have a dominant negative effect on enzyme function, resulting in defective proliferation, survival of B-2 cells, causing a block in B cell development, and impair humoral function in response to immunization.

Distinctive pro-inflammatory gene signatures induced in articular chondrocytes by oncostatin M and IL-6 are regulated by Suppressor of Cytokine Signaling-3

Publisher: Elsevier BV

Date: 10-2015

DOI: 10.1016/J.JOCA.2015.05.011

Abstract: To describe gene expression in murine chondrocytes stimulated with IL-6 family cytokines and the impact of deleting Suppressor of Cytokine Signaling-3 (SOCS-3) in this cell type. Primary chondrocytes were isolated from wild type and SOCS-3-deficient (Socs3(Δ/Δcol2)) mice and stimulated with oncostatin M (OSM), IL-6 plus the soluble IL-6 receptor (IL-6/sIL-6R), IL-11 or leukemia inhibitory factor (LIF) for 4 h. Total RNA was extracted and gene expression was evaluated by microarray analysis. Validation of the microarray results was performed using Taqman probes on RNA derived from chondrocytes stimulated for 1, 2, 4 or 8 h. Gene ontology was characterized using DAVID (database for annotation, visualization and integrated discovery). Multiple genes, including Bcl3, Junb, Tgm1, Angptl4 and Lrg1, were upregulated in chondrocytes stimulated with each gp130 cytokine. The gene transcription profile in response to OSM stimulation was pro-inflammatory and was highly correlated to IL-6/sIL-6R, rather than IL-11 or LIF. In the absence of SOCS-3, OSM and IL-6/sIL-6R stimulation induced an interferon (IFN)-like gene signature, including expression of IL-31ra and S100a9. While each gp130 cytokine induced a transcriptional response in chondrocytes, OSM- and IL-6/sIL-6R were the most potent members of this cytokine family. SOCS-3 plays an important regulatory role in this cell type, as it does in hematopoietic cells. Our results provide new insights into a hierarchy of gp130-induced transcriptional responses in chondrocytes that is normally restrained by SOCS-3 and suggest therapeutic inhibition of OSM may have benefit over and above antagonism of IL-6 during inflammatory arthritis.

A key role for G-CSF induced neutrophil production and trafficking during inflammatory arthritis

Publisher: American Society of Hematology

Date: 15-12-2008

DOI: 10.1182/BLOOD-2008-02-139535

Abstract: We have previously shown that G-CSF–deficient (G-CSF−/−) mice are markedly protected from collagen-induced arthritis (CIA), which is the major murine model of rheumatoid arthritis, and now investigate the mechanisms by which G-CSF can promote inflammatory disease. Serum G-CSF levels were significantly elevated during CIA. Reciprocal bone marrow chimeras using G-CSF−/−, G-CSFR−/−, and wild-type (WT) mice identified nonhematopoietic cells as the major producers of G-CSF and hematopoietic cells as the major responders to G-CSF during CIA. Protection against CIA was associated with relative neutropenia. Depletion of neutrophils or blockade of the neutrophil adhesion molecule, Mac-1, dramatically attenuated the progression of established CIA in WT mice. Intravital microscopy of the microcirculation showed that both local and systemic administration of G-CSF significantly increased leukocyte trafficking into tissues in vivo. G-CSF–induced trafficking was Mac-1 dependent, and G-CSF up-regulated CD11b expression on neutrophils. Multiphoton microscopy of synovial vessels in the knee joint during CIA revealed significantly fewer adherent Gr-1+ neutrophils in G-CSF−/− mice compared with WT mice. These data confirm a central proinflammatory role for G-CSF in the pathogenesis of inflammatory arthritis, which may be due to the promotion of neutrophil trafficking into inflamed joints, in addition to G-CSF–induced neutrophil production.

Aberrant actin depolymerization triggers the pyrin inflammasome and autoinflammatory disease that is dependent on IL-18, not IL-1β

Publisher: Rockefeller University Press

Date: 25-05-2015

DOI: 10.1084/JEM.20142384

Abstract: Gain-of-function mutations that activate the innate immune system can cause systemic autoinflammatory diseases associated with increased IL-1β production. This cytokine is activated identically to IL-18 by an intracellular protein complex known as the inflammasome however, IL-18 has not yet been specifically implicated in the pathogenesis of hereditary autoinflammatory disorders. We have now identified an autoinflammatory disease in mice driven by IL-18, but not IL-1β, resulting from an inactivating mutation of the actin-depolymerizing cofactor Wdr1. This perturbation of actin polymerization leads to systemic autoinflammation that is reduced when IL-18 is deleted but not when IL-1 signaling is removed. Remarkably, inflammasome activation in mature macrophages is unaltered, but IL-18 production from monocytes is greatly exaggerated, and depletion of monocytes in vivo prevents the disease. Small-molecule inhibition of actin polymerization can remove potential danger signals from the system and prevents monocyte IL-18 production. Finally, we show that the inflammasome sensor of actin dynamics in this system requires caspase-1, apoptosis-associated speck-like protein containing a caspase recruitment domain, and the innate immune receptor pyrin. Previously, perturbation of actin polymerization by pathogens was shown to activate the pyrin inflammasome, so our data now extend this guard hypothesis to host-regulated actin-dependent processes and autoinflammatory disease.

Regulation of interleukin-1β by interferon-γ is species specific, limited by suppressor of cytokine signalling 1 and influences interleukin-17 production

Publisher: EMBO

Date: 02-07-2010

DOI: 10.1038/EMBOR.2010.93

NOD1 mediates interleukin-18 processing in epithelial cells responding to Helicobacter pylori infection

Publisher: Research Square Platform LLC

Date: 09-09-2020

DOI: 10.21203/RS.3.RS-49701/V1

Abstract: The interleukin-1 family members, IL-1β and IL-18, are processed into their biologically active forms by multi-protein complexes, known as inflammasomes. Although the inflammasome pathways that mediate IL-1β processing in myeloid cells have been well defined, those involved in IL-18 processing, particularly in non-myeloid cells, are still not well understood. Here, we report that the host defence molecule NOD1 regulates IL-18 processing in epithelial cells to the mucosal pathogens, Helicobacter pylori and Pseudomonas aeruginosa . We show that IL-18 is important in protecting against pre-neoplastic changes induced by gastric H. pylori infection in vivo . NOD1 mediates IL-18 processing via homotypic CARD-CARD interactions with caspase-1, and independently of canonical inflammasome proteins (NLRP3, ASC). These findings reveal an unanticipated role for NOD1 in the formation of bioactive IL-18, thereby underlining the differences in inflammasome functions between haematopoietic and non-haematopoietic cells.

Deleting Suppressor of Cytokine Signaling-3 in chondrocytes reduces bone growth by disrupting mitogen-activated protein kinase signaling

Publisher: Elsevier BV

Date: 10-2019

DOI: 10.1016/J.JOCA.2019.05.018

Abstract: To investigate the impact of deleting Suppressor of Cytokine Signaling (SOCS)-3 (SOCS3) in chondrocytes during murine skeletal development. Mice with a conditional Socs3 allele (Socs3 Socs3 Our results suggest a potential role for SOCS3 in GP chondrocyte proliferation by regulating FGFR3-dependent MAPK signaling in response to FGF18.

SOCS3 negatively regulates IL-6 signaling in vivo

Publisher: Springer Science and Business Media LLC

Date: 18-05-2003

DOI: 10.1038/NI931

Walking down the memory lane with SARS-CoV-2 B cells.

Publisher: Wiley

Date: 06-08-2021

DOI: 10.1111/IMCB.12494

Surfactant deficiency increases SARS-CoV-2 canonical and non-canonical viral entry to lung epithelial cells and exacerbates intrapulmonary inflammatory responses

Publisher: Research Square Platform LLC

Date: 18-04-2023

DOI: 10.21203/RS.3.RS-2694520/V1

Abstract: The prevalence of “Long COVID”, including among vaccinated patients, is just one of the conundrums that indicate how much remains unknown about the lung’s response to viral infection, particularly to SARS-CoV-2 for which the lung is the point of entry. Therefore, we used an in vitro human lung system to enable a prospective, unbiased, sequential single cell level analysis of pulmonary cell responses following infection by multiple strains of SARS-CoV-2. By starting with human induced pluripotent stem cells (hiPSCs) and emulating lung organogenesis, three-dimensional lung organoids were generated and infected in which several unexpected but pertinent insights emerged. First, SARS-CoV-2 tropism is much broader than previously believed: most lung cell types can be infected, if not through a canonical receptor-mediated route (e.g., via ACE2) then via a non-canonical “backdoor” endocytosis/micropinocytosis route. Such entry can be abrogated by FDA-approved endocytosis blockers, suggesting novel adjunctive therapies. Regardless of route-of-entry, the virus triggers a heretofore unrecognized lung epithelial cell-intrinsic autonomous innate immune response involving interferons and cytokine/chemokine production in the absence of hematopoietic cells or their derivatives. The virus can spread rapidly throughout human lung organoid cell cultures resulting in mitochondrial apoptosis mediated by the pro-survival protein Bcl-xL. This host cytopathic response to the virus may help explain persistent inflammatory signatures in a dysfunctional pulmonary environment of long COVID. The host response to the virus is, in part, dependent on the presence of pulmonary Surfactant Protein-B (SP-B), which plays an unanticipated role in signal transduction, viral resistance, d ens systemic inflammatory cytokine production, and minimizes the induction of apoptosis.

The pseudokinase MLKL activates PAD4-dependent NET formation in necroptotic neutrophils

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

Date: 04-09-2018

DOI: 10.1126/SCISIGNAL.AAO1716

Abstract: RIPK1-dependent necroptotic cell death stimulates neutrophil NET formation to control MRSA infection.

NLRP1 inflammasome activation induces pyroptosis of hematopoietic progenitor cells.

Publisher: Elsevier BV

Date: 12-2012

DOI: 10.1016/J.IMMUNI.2012.08.027

Neutrophils require SHP1 to regulate IL-1β production and prevent inflammatory skin disease

Publisher: The American Association of Immunologists

Date: 15-01-2011

DOI: 10.4049/JIMMUNOL.1002702

Abstract: The regulation of neutrophil recruitment, activation, and disposal is pivotal for circumscribed inflammation. SHP1Y208N/Y208N mutant mice develop severe cutaneous inflammatory disease that is IL-1R dependent. Genetic reduction in neutrophil numbers and neutrophilic responses to infection is sufficient to prevent the spontaneous initiation of this disease. Neutrophils from SHP1Y208N/Y208N mice display increased pro–IL-1β production due to altered responses to MyD88-dependent and MyD88-independent signals. The IL-1R–dependent inflammatory disease in SHP1Y208N/Y208N mice develops independently of caspase 1 and proteinase 3 and neutrophil elastase. In response to Fas ligand, a caspase 1-independent inducer of IL-1β production, neutrophils from SHP1Y208N/Y208N mice produce elevated levels of IL-1β but display reduced caspase 3 and caspase 7 activation. In neutrophils deficient in SHP1, IL-1β induces high levels of pro–IL-1β suggesting the presence of a paracrine IL-1β loop. These data indicate that the neutrophil- and IL-1–dependent disease in SHP1Y208N/Y208N mice is a consequence of loss of negative regulation of TLR and IL-1R signaling.

A Helicobacter pylori homolog of eukaryotic flotillin is involved in cholesterol accumulation, epithelial cell responses and host colonization

Publisher: Frontiers Media SA

Date: 06-06-2017

DOI: 10.3389/FCIMB.2017.00219

Inflammation and autoimmunity caused by a SHP1 mutation depend on IL-1, MyD88, and a microbial trigger (Proceedings of the National Academy of Sciences of the United States of America (2008) 105, 39, (15028-15033) DOI:10.1073/pnas.0806619105)

Publisher: Proceedings of the National Academy of Sciences

Date: 09-12-2008

DOI: 10.1073/PNAS.0810917105

IL-18 Production from the NLRP1 Inflammasome Prevents Obesity and Metabolic Syndrome

Publisher: Elsevier BV

Date: 2016

DOI: 10.1016/J.CMET.2015.09.024

Abstract: Interleukin-18 (IL-18) is activated by Caspase-1 in inflammasome complexes and has anti-obesity effects however, it is not known which inflammasome regulates this process. We found that mice lacking the NLRP1 inflammasome phenocopy mice lacking IL-18, with spontaneous obesity due to intrinsic lipid accumulation. This is exacerbated when the mice are fed a high-fat diet (HFD) or a high-protein diet, but not when mice are fed a HFD with low energy density (high fiber). Furthermore, mice with an activating mutation in NLRP1, and hence increased IL-18, have decreased adiposity and are resistant to diet-induced metabolic dysfunction. Feeding these mice a HFD further increased plasma IL-18 concentrations and strikingly resulted in loss of adipose tissue mass and fatal cachexia, which could be prevented by genetic deletion of IL-18. Thus, NLRP1 is an innate immune sensor that functions in the context of metabolic stress to produce IL-18, preventing obesity and metabolic syndrome.

Defining a therapeutic window for kinase inhibitors in leukemia to avoid neutropenia.

Publisher: Impact Journals, LLC

Date: 28-07-2017

DOI: 10.18632/ONCOTARGET.19678

SOCS-3 negatively regulates innate and adaptive immune mechanisms in acute IL-1-dependent inflammatory arthritis

Publisher: American Society for Clinical Investigation

Date: 06-2006

DOI: 10.1172/JCI25660

SOCS3 Is a Critical Physiological Negative Regulator of G-CSF Signaling and Emergency Granulopoiesis

Publisher: Elsevier BV

Date: 02-2004

DOI: 10.1016/S1074-7613(04)00022-6

Abstract: To determine the importance of suppressor of cytokine signaling-3 (SOCS3) in the regulation of hematopoietic growth factor signaling generally, and of G-CSF-induced cellular responses specifically, we created mice in which the Socs3 gene was deleted in all hematopoietic cells. Although normal until young adulthood, these mice then developed neutrophilia and a spectrum of inflammatory pathologies. When stimulated with G-CSF in vitro, SOCS3-deficient cells of the neutrophilic granulocyte lineage exhibited prolonged STAT3 activation and enhanced cellular responses to G-CSF, including an increase in cloning frequency, survival, and proliferative capacity. Consistent with the in vitro findings, mutant mice injected with G-CSF displayed enhanced neutrophilia, progenitor cell mobilization, and splenomegaly, but unexpectedly also developed inflammatory neutrophil infiltration into multiple tissues and consequent hind-leg paresis. We conclude that SOCS3 is a key negative regulator of G-CSF signaling in myeloid cells and that this is of particular significance during G-CSF-driven emergency granulopoiesis.

Single-cell cloning of human T-cell lines reveals clonal variation in cell death responses to chemotherapeutics.

Publisher: Elsevier BV

Date: 09-2019

DOI: 10.1016/J.CANCERGEN.2019.06.003

Immune response to intravenous immunoglobulin in patients with Kawasaki disease and MIS-C

Publisher: American Society for Clinical Investigation

Date: 15-10-2021

DOI: 10.1172/JCI147076

Fas regulates neutrophil lifespan during viral and bacterial infection

Publisher: Oxford University Press (OUP)

Date: 03-12-2015

DOI: 10.1189/JLB.3AB1113-594RR

Abstract: Neutrophils use Toll-like receptor and IL-18 signaling to reprogram Fas-induced death. The regulation of neutrophil lifespan is critical for a circumscribed immune response. Neutrophils are sensitive to Fas/CD95 death receptor signaling in vitro, but it is unknown if Fas regulates neutrophil lifespan in vivo. We hypothesized that FasL-expressing CD8+ T cells, which kill antigen-stimulated T cells during chronic viral infection, can also induce neutrophil death in tissues during infection. With the use of LysM-Cre Fasfl/fl mice, which lack Fas expression in macrophages and neutrophils, we show that Fas regulates neutrophil lifespan during lymphocytic choriomeningitis virus (LCMV) infection in the lung, peripheral blood, and spleen. Fas also contributed to the regulation of neutrophil numbers in the colon of Citrobacter rodentium-infected mice. To examine the effects of infection on Fas activation in neutrophils, we primed neutrophils with TLR ligands or IL-18, resulting in ablation of Fas death receptor signaling. These data provide the first in vivo genetic evidence that neutrophil lifespan is controlled by death receptor signaling and provide a mechanism to account for neutrophil resistance to Fas stimulation during infection.

Myelopoiesis embraces its inner weakness

Publisher: Springer Science and Business Media LLC

Date: 22-08-2017

DOI: 10.1038/NI.3814

Translation inhibitors induce cell death by multiple mechanisms and Mcl-1 reduction is only a minor contributor

Publisher: Springer Science and Business Media LLC

Date: 11-10-2012

DOI: 10.1038/CDDIS.2012.149

Pyroptotic death storms and cytopenia

Publisher: Elsevier BV

Date: 02-2014

DOI: 10.1016/J.COI.2013.12.002

Abstract: For over two decades, we have embraced the cytokine storm theory to explain sepsis, severe sepsis and septic shock. The failure of numerous large-scale clinical trials, which aimed to treat sepsis by neutralizing inflammatory cytokines and LPS, indicates that alternative pathophysiological mechanisms are likely to account for sepsis and the associated immune suppression in patients with severe infection. Recent insights that extricate pyroptotic death from inflammatory cytokine production in vivo have highlighted a need to investigate the consequences of apoptotic and non-apoptotic death in contributing to cytopenia and immune suppression. In this review, we will focus on the biochemical and cellular mechanisms controlling pyroptosis, a Caspase-1/11 dependent form of cell death during infection.

Towards a four-dimensional view of neutrophils

Publisher: Humana Press

Date: 21-12-2012

DOI: 10.1007/978-1-61779-527-5_6

Abstract: Neutrophils are constitutively produced throughout adult life and are essential for host responses to many types of pathogen. Neutropenia has long been associated with poor prognosis in the clinic, yet we have an incomplete understanding of their life cycle, not only during homeostasis but also during infection and chronic inflammation. Here, we review recent advances that provide insight into the genetic and biochemical regulators of neutrophil production, function, and survival.

Selective FcγR Co-engagement on APCs Modulates the Activity of Therapeutic Antibodies Targeting T Cell Antigens.

Publisher: Elsevier BV

Date: 06-2018

DOI: 10.1016/J.CCELL.2018.05.005

NLRP1a Expression in Srebp-1a-Deficient Mice

Publisher: Elsevier BV

Date: 03-2014

DOI: 10.1016/J.CMET.2014.02.002

Thrombocytopenia and kidney disease in mice with a mutation in the C1galt1 gene

Publisher: Proceedings of the National Academy of Sciences

Date: 31-10-2006

DOI: 10.1073/PNAS.0607872103

Abstract: An N -ethyl- N -nitrosourea mutagenesis screen in mice was performed to isolate regulators of circulating platelet number. We report here recessive thrombocytopenia and kidney disease in plt1 mice, which is the result of a severe but partial loss-of-function mutation in the gene encoding glycoprotein- N -acetylgalactosamine-3-β-galactosyltransferase (C1GalT1), an enzyme essential for the synthesis of extended mucin-type O-glycans. Platelet half-life and basic hemostatic parameters were unaffected in plt1 lt1 mice, and the thrombocytopenia and kidney disease were not attenuated on a lymphocyte-deficient rag1 -null background. gpIbα and podocalyxin were found to be major underglycosylated proteins in plt1 lt1 platelets and the kidney, respectively, implying that these are key targets for C1GalT1, appropriate glycosylation of which is essential for platelet production and kidney function. Compromised C1GalT1 activity has been associated with immune-mediated diseases in humans, most notably Tn syndrome and IgA nephropathy. The disease in plt1 lt1 mice suggests that, in addition to immune-mediated effects, intrinsic C1Gal-T1 deficiency in megakaryocytes and the kidney may contribute to pathology.

β-glucan–dependent shuttling of conidia from neutrophils to macrophages occurs during fungal infection establishment

Publisher: Public Library of Science (PLoS)

Date: 04-09-2019

DOI: 10.1371/JOURNAL.PBIO.3000113

Fight or flight: Regulation of emergency hematopoiesis by pyroptosis and necroptosis

Publisher: Ovid Technologies (Wolters Kluwer Health)

Date: 07-2015

DOI: 10.1097/MOH.0000000000000148

Inflammation and autoimmunity caused by a SHP1 mutation depend on IL-1, MyD88, and a microbial trigger

Publisher: Proceedings of the National Academy of Sciences

Date: 30-09-2008

DOI: 10.1073/PNAS.0806619105

Abstract: A recessive phenotype called spin (spontaneous inflammation) was induced by N -ethyl- N -nitrosourea (ENU) mutagenesis in C57BL/6J mice. Homozygotes display chronic inflammatory lesions affecting the feet, salivary glands and lungs, and antichromatin antibodies. They are immunocompetent and show enhanced resistance to infection by Listeria monocytogenes . TLR-induced TNF and IL-1 production are normal in macrophages derived from spin mice. The autoinflammatory phenotype of spin mice is fully suppressed by compound homozygosity for Myd88 poc , Irak4 otiose , and Il1r1 -null mutations, but not Ticam1 Lps2 , Stat1 m1Btlr , or Tnf -null mutations. Both autoimmune and autoinflammatory phenotypes are suppressed when spin homozygotes are derived into a germ-free environment. The spin phenotype was ascribed to a viable hypomorphic allele of Ptpn6 , which encodes the tyrosine phosphatase SHP1, mutated in mice with the classical motheaten alleles me and me-v . Inflammation and autoimmunity caused by SHP1 deficiency are thus conditional. The SHP1-deficient phenotype is driven by microbes, which activate TLR signaling pathways to elicit IL-1 production. IL-1 signaling via MyD88 elicits inflammatory disease.

Cutting Edge: Blockade of Inhibitor of Apoptosis Proteins Sensitizes Neutrophils to TNF- but Not Lipopolysaccharide-Mediated Cell Death and IL-1b Secretion

Publisher: The American Association of Immunologists

Date: 15-05-2018

DOI: 10.4049/JIMMUNOL.1701620

Abstract: The mammalian inhibitor of apoptosis proteins (IAPs) are key regulators of cell death and inflammation. A major function of IAPs is to block the formation of a cell death–inducing complex, termed the ripoptosome, which can trigger caspase-8–dependent apoptosis or caspase-independent necroptosis. Recent studies report that upon TLR4 or TNF receptor 1 (TNFR1) signaling in macrophages, the ripoptosome can also induce NLRP3 inflammasome formation and IL-1β maturation. Whether neutrophils have the capacity to assemble a ripoptosome to induce cell death and inflammasome activation during TLR4 and TNFR1 signaling is unclear. In this study, we demonstrate that murine neutrophils can signal via TNFR1-driven ripoptosome assembly to induce both cell death and IL-1β maturation. However, unlike macrophages, neutrophils suppress TLR4-dependent cell death and NLRP3 inflammasome activation during IAP inhibition via deficiencies in the CD14/TRIF arm of TLR4 signaling.

Scripps Research Institute

Location: United States of America

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University Of Melbourne

Location: Australia

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University Of New South Wales

Location: Australia

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Boston Children's Hospital

Location: United States of America

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University Of California, San Diego

Location: United States of America

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Walter And Eliza Hall Institute Of Medical Research

Location: Australia

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Discovery Projects - Grant ID: DP1094854

Start Date: 2010

End Date: 12-2014

Amount: $597,970.00

Funder: Australian Research Council