ORCID Profile
0000-0002-1957-9732
Current Organisation
University of Sydney
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Genomics | Genetics | Epigenetics (incl. Genome Methylation and Epigenomics) | Molecular Evolution | Biochemistry and Cell Biology | Signal Transduction | Biomechanical Engineering | Systems Biology | Cell Development, Proliferation and Death
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 17-08-2007
DOI: 10.1161/CIRCRESAHA.107.158659
Abstract: Apelin constitutes a novel endogenous peptide system suggested to be involved in a broad range of physiological functions, including cardiovascular function, heart development, control of fluid homeostasis, and obesity. Apelin is also a catalytic substrate for angiotensin-converting enzyme 2, the key severe acute respiratory syndrome receptor. The in vivo physiological role of Apelin is still elusive. Here we report the generation of Apelin gene–targeted mice. Apelin mutant mice are viable and fertile, appear healthy, and exhibit normal body weight, water and food intake, heart rates, and heart morphology. Intriguingly, aged Apelin knockout mice developed progressive impairment of cardiac contractility associated with systolic dysfunction in the absence of histological abnormalities. We also report that pressure overload induces upregulation of Apelin expression in the heart. Importantly, in pressure overload–induced heart failure, loss of Apelin did not significantly affect the hypertrophy response, but Apelin mutant mice developed progressive heart failure. Global gene expression arrays and hierarchical clustering of differentially expressed genes in hearts of banded Apelin −/y and Apelin +/y mice showed concerted upregulation of genes involved in extracellular matrix remodeling and muscle contraction. These genetic data show that the endogenous peptide Apelin is crucial to maintain cardiac contractility in pressure overload and aging.
Publisher: Springer Science and Business Media LLC
Date: 29-02-2008
DOI: 10.1038/CDD.2008.24
Publisher: American Association for the Advancement of Science (AAAS)
Date: 17-07-2009
Abstract: Drosophila melanogaster is an important model system to study innate immunity, being both easy to manipulate and lacking an adaptive immune system. In order to identify genes that regulate innate immunity, Cronin et al. (p. 340 published online 11 June) performed an RNA interference screen on flies infected with the oral bacterial pathogen, Serratia marcescens . Genes involved in intestinal immunity and regulation of hemocytes, macrophage-like cells critical for phagocytosis and killing of the bacteria, were identified. Several hundred genes conferred either enhanced susceptibility or resistance to bacterial infection. Furthermore, the JAK/STAT signaling pathway was activated in intestinal stem cells after bacterial infection, resulting in enhanced susceptibility to infection, most likely through regulation of intestinal stem cell homeostasis.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 02-2020
DOI: 10.1097/J.PAIN.0000000000001733
Abstract: Neuropathic pain causes severe suffering, and most patients are resistant to current therapies. A core element of neuropathic pain is the loss of inhibitory tone in the spinal cord. Previous studies have shown that foetal GABAergic neuron precursors can provide relief from pain. However, the source of these precursor cells and their multipotent status make them unsuitable for therapeutic use. Here, we extend these findings by showing, for the first time, that spinally transplanted, terminally differentiated human induced pluripotent stem cell-derived GABAergic (iGABAergic) neurons provide significant, long-term, and safe relief from neuropathic pain induced by peripheral nerve injury in mice. Furthermore, iGABAergic neuron transplants survive long term in the injured spinal cord and show evidence of synaptic integration. Together, this provides the proof in principle for the first viable GABAergic transplants to treat human neuropathic pain patients.
Publisher: Public Library of Science (PLoS)
Date: 05-07-2018
Publisher: Elsevier BV
Date: 07-2022
DOI: 10.1016/J.ENVPOL.2022.119081
Abstract: Per- and polyfluoroalkyl substances (PFAS) are ubiquitous in the environment and often ingested with food. PFAS exposure in people can have detrimental health consequences. Therefore, reducing PFAS burdens in food items is of great importance to public health. Here, we investigated whether cooking reduces PFAS concentrations in animal-derived food products by synthesizing experimental studies. Further, we examined the moderating effects of the following five variables: cooking time, liquid/animal tissue ratio, cooking temperature, carbon chain length of PFAS and the cooking category (oil-based, water-based & no-liquid cooking). In our systematic review searches, we obtained 512 effect sizes (relative differences in PFAS concentration between raw and cooked s les) from 10 relevant studies. These studies exclusively explored changes in PFAS concentrations in cooked seafood and freshwater fish. Our multilevel-meta-analysis has revealed that, on average, cooking reduced PFAS concentrations by 29%, although heterogeneity among effect sizes was very high (I
Publisher: Springer Science and Business Media LLC
Date: 30-11-2017
DOI: 10.1038/S41598-017-00097-9
Abstract: Cell state switches underlie a plethora of biological phenomena and disease treatment strategies. Hence the ability to efficiently switch states in a chosen direction is of central importance in a number of scenarios. Increasing the concentration of an effector that results in a given switch is often limited by side effects. Approaches are thus increasingly sought to bypass these constraints, increasing the frequency of state switching without increasing the frequency of the side effect. Here, we employ dynamical systems theory to uncover a simple strategy as to how to maximize the probability of reactivating latent Human immunodeficiency virus (HIV) whilst maintaining minimal side effects. We demonstrate that continuous supply of an effector is significantly more likely to result in a switch with minimal side effects than the same effector supplied in temporally discrete doses. Importantly this continual dosage is likely to occur far below the Minimum effective dose at a concentration that has classically been thought subtherapeutic. We therefore suggest that in many interventional settings there exists potential to reduce drug dose much further than has previously been thought possible yet still maintaining efficacy.
Publisher: The American Association of Immunologists
Date: 04-2004
DOI: 10.4049/JIMMUNOL.172.7.4225
Abstract: IL-15 is a short chain, four-α helix cytokine that shares some biological function with IL-2. One striking difference between IL-2 and IL-15 is the ability of monocytes to express IL-15 on their cell surface after activation. In the current study we have investigated the ability of human monocyte cell surface IL-15 to participate in reverse signaling. Cross-linking anti-IL-15 Abs were used as a surrogate ligand for surface IL-15 engagement. Ligation of cell surface-expressed IL-15 induced monocyte adhesion that required the activity of small m.w. GTPases. Reverse signals through surface IL-15 activated the Rho-GTPase Rac3. In addition, engagement of cell surface IL-15 was found to activate a number of signaling pathways, including both extracellular signal-regulated kinase 1/2 and p38, and resulted in the secretion of IL-8. IL-8 production required mitogen-activated protein kinase activity. Thus, the current study has established that cell surface IL-15 is more than just a ligand it can function as a receptor and participate in reverse signaling that results in cellular adhesion and production of inflammatory cytokines.
Publisher: Springer Science and Business Media LLC
Date: 12-2017
DOI: 10.1038/S41598-017-16849-6
Abstract: Water intake is essential for survival and thus under strong regulation. Here, we describe a simple high throughput system to monitor water intake over time in Drosophila . The design of the assay involves dehydrating fly food and then adding water back separately so flies either eat or drink. Water consumption is then evaluated by weighing the water vessel and comparing this back to an evaporation control. Our system is high throughput, does not require animals to be artificially dehydrated, and is simple both in design and implementation. Initial characterisation of homeostatic water consumption shows high reproducibility between biological replicates in a variety of experimental conditions. Water consumption was dependent on ambient temperature and humidity and was equal between sexes when corrected for mass. By combining this system with the Drosophila genetics tools, we could confirm a role for ppk28 and DopR1 in promoting water consumption, and through functional investigation of RNAseq data from dehydrated animals, we found DopR1 expression in the mushroom body was sufficient to drive consumption and enhance water taste sensitivity. Together, we provide a simple high throughput water consumption assay that can be used to dissect the cellular and molecular machinery regulating water homeostasis in Drosophila .
Publisher: MDPI AG
Date: 27-12-2022
DOI: 10.3390/LIFE13010081
Abstract: Many studies show that genetics play a major contribution to the onset of obesity. Human genome-wide association studies (GWASs) have identified hundreds of genes that are associated with obesity. However, the majority of them have not been functionally validated. SEC16B has been identified in multiple obesity GWASs but its physiological role in energy homeostasis remains unknown. Here, we use Drosophila to determine the physiological functions of dSec16 in energy metabolism. Our results showed that global RNAi of dSec16 increased food intake and triglyceride (TAG) levels. Furthermore, this TAG increase was observed in flies with a specific RNAi of dSec16 in insulin-like peptide producing cells (IPCs) with an alteration of endocrine peptides. Together, our study demonstrates that dSec16 acting in IPCs controls energy balance and advances the molecular understanding of obesity.
Publisher: Elsevier BV
Date: 08-2017
DOI: 10.1016/J.CMET.2017.07.002
Abstract: Despite widespread consumption of non-nutritive sweeteners (NNSs), the impact of manipulating the perceived sweetness of food is unclear. Previously we reported that chronic consumption of the NNSs sucralose or L-glucose led to increased calories consumed post-exposure however, a recent study suggested this effect occurs because NNSs acutely suppress food intake, leading to a caloric debt. Here we show that acute ingestion of sucralose in the context of a low-carbohydrate diet causes a pronounced increase in calories consumed. Moreover, neither sucralose nor L-glucose had a lasting effect on food intake during chronic exposure however, both NNSs enhance food intake post-exposure. Together these data confirm that sucralose and L-glucose promote food intake under a variety of experimental conditions.
Publisher: Springer Science and Business Media LLC
Date: 28-04-2023
DOI: 10.1038/S41467-023-37963-2
Abstract: Voltage-gated sodium (Na V ) channels are critical regulators of neuronal excitability and are targeted by many toxins that directly interact with the pore-forming α subunit, typically via extracellular loops of the voltage-sensing domains, or residues forming part of the pore domain. Excelsatoxin A (ExTxA), a pain-causing knottin peptide from the Australian stinging tree Dendrocnide excelsa , is the first reported plant-derived Na V channel modulating peptide toxin. Here we show that TMEM233, a member of the dispanin family of transmembrane proteins expressed in sensory neurons, is essential for pharmacological activity of ExTxA at Na V channels, and that co-expression of TMEM233 modulates the gating properties of Na V 1.7. These findings identify TMEM233 as a previously unknown Na V 1.7-interacting protein, position TMEM233 and the dispanins as accessory proteins that are indispensable for toxin-mediated effects on Na V channel gating, and provide important insights into the function of Na V channels in sensory neurons.
Publisher: MDPI AG
Date: 20-11-2020
DOI: 10.3390/CELLS9112517
Abstract: Neurodegenerative diseases are characterized by irreversible cell damage, loss of neuronal cells and limited regeneration potential of the adult nervous system. Pluripotent stem cells are capable of differentiating into the multitude of cell types that compose the central and peripheral nervous systems and so have become the major focus of cell replacement therapies for the treatment of neurological disorders. Human embryonic stem cell (hESC) and human induced pluripotent stem cell (hiPSC)-derived cells have both been extensively studied as cell therapies in a wide range of neurodegenerative disease models in rodents and non-human primates, including Parkinson’s disease, stroke, epilepsy, spinal cord injury, Alzheimer’s disease, multiple sclerosis and pain. In this review, we discuss the latest progress made with stem cell therapies targeting these pathologies. We also evaluate the challenges in clinical application of human pluripotent stem cell (hPSC)-based therapies including risk of oncogenesis and tumor formation, immune rejection and difficulty in regeneration of the heterogeneous cell types composing the central nervous system.
Publisher: Public Library of Science (PLoS)
Date: 22-02-2010
Publisher: Elsevier BV
Date: 06-2020
Publisher: Springer Science and Business Media LLC
Date: 22-10-2015
DOI: 10.1038/NCOMMS9570
Abstract: Disease incidences increase with age, but the molecular characteristics of ageing that lead to increased disease susceptibility remain inadequately understood. Here we perform a whole-blood gene expression meta-analysis in 14,983 in iduals of European ancestry (including replication) and identify 1,497 genes that are differentially expressed with chronological age. The age-associated genes do not harbor more age-associated CpG-methylation sites than other genes, but are instead enriched for the presence of potentially functional CpG-methylation sites in enhancer and insulator regions that associate with both chronological age and gene expression levels. We further used the gene expression profiles to calculate the ‘transcriptomic age’ of an in idual, and show that differences between transcriptomic age and chronological age are associated with biological features linked to ageing, such as blood pressure, cholesterol levels, fasting glucose, and body mass index. The transcriptomic prediction model adds biological relevance and complements existing epigenetic prediction models, and can be used by others to calculate transcriptomic age in external cohorts.
Publisher: Cold Spring Harbor Laboratory
Date: 22-09-2023
Publisher: Oxford University Press (OUP)
Date: 23-11-2013
DOI: 10.1093/HMG/DDT594
Publisher: EMBO
Date: 14-12-2018
Publisher: Springer Science and Business Media LLC
Date: 16-05-2023
DOI: 10.1038/S41467-023-37714-3
Abstract: The “death cap”, Amanita phalloides , is the world’s most poisonous mushroom, responsible for 90% of mushroom-related fatalities. The most fatal component of the death cap is α-amanitin. Despite its lethal effect, the exact mechanisms of how α-amanitin poisons humans remain unclear, leading to no specific antidote available for treatment. Here we show that STT3B is required for α-amanitin toxicity and its inhibitor, indocyanine green (ICG), can be used as a specific antidote. By combining a genome-wide CRISPR screen with an in silico drug screening and in vivo functional validation, we discover that N-glycan biosynthesis pathway and its key component, STT3B, play a crucial role in α-amanitin toxicity and that ICG is a STT3B inhibitor. Furthermore, we demonstrate that ICG is effective in blocking the toxic effect of α-amanitin in cells, liver organoids, and male mice, resulting in an overall increase in animal survival. Together, by combining a genome-wide CRISPR screen for α-amanitin toxicity with an in silico drug screen and functional validation in vivo, our study highlights ICG as a STT3B inhibitor against the mushroom toxin.
Publisher: Frontiers Media SA
Date: 15-05-2019
Publisher: Elsevier BV
Date: 12-2017
Publisher: Elsevier BV
Date: 04-2008
Publisher: Future Medicine Ltd
Date: 11-2013
DOI: 10.2217/PGS.13.196
Abstract: Chronic pain is a disabling condition that persists even after normal healing processes are complete and presents considerable physical, psychological and financial burdens for patients globally. However, current analgesic treatments do not meet clinical needs. Here, we review genomic and pharmacogenomic studies of pain in humans and nociception in the fruit fly Drosophila melanogaster, and provide evidence supporting the use of fly genetics to compliment genome-wide and pharmacogenomic studies of human conditions, such as pain. Combining genomic and pharmacogenomic techniques to study chronic pain in humans with functional genomic assessment in model organisms may provide molecular rationale for developing more personalized or improving generalized chronic pain therapies.
Publisher: Springer Science and Business Media LLC
Date: 21-07-2017
DOI: 10.1007/S00429-017-1473-4
Abstract: The phenotype of calcium channel subunit (CACN) α2δ3 knockout (KO) mice includes sensory cross-activation and deficient pain perception. Sensory cross-activation defines the activation of a sensory cortical region by input from another modality due to reorganization in the brain such as after sensory loss. To obtain mechanistic insight into both phenomena, we employed a comprehensive battery of neuroanatomical techniques. While CACNα2δ3 was ubiquitously expressed in wild-type mice, it was absent in α2δ3 KO animals. Immunostaining of α1A, α1B, and α1E revealed upregulation of N-type and R-type, but not P/Q-type Ca
Publisher: Elsevier BV
Date: 11-2020
Publisher: Springer Science and Business Media LLC
Date: 02-2019
DOI: 10.1038/S41467-019-08492-8
Abstract: Hundreds of genetic variants have been associated with Body Mass Index (BMI) through genome-wide association studies (GWAS) using observational cohorts. However, the genetic contribution to efficient weight loss in response to dietary intervention remains unknown. We perform a GWAS in two large low-caloric diet intervention cohorts of obese participants. Two loci close to NKX6.3/MIR486 and RBSG4 are identified in the Canadian discovery cohort ( n = 1166) and replicated in the DiOGenes cohort ( n = 789). Modulation of HGTX ( NKX6.3 ortholog) levels in Drosophila melanogaster leads to significantly altered triglyceride levels. Additional tissue-specific experiments demonstrate an action through the oenocytes, fly hepatocyte-like cells that regulate lipid metabolism. Our results identify genetic variants associated with the efficacy of weight loss in obese subjects and identify a role for NKX6.3 in lipid metabolism, and thereby possibly weight control.
Publisher: Wiley
Date: 29-07-2022
DOI: 10.1111/BPH.15923
Abstract: Over past decades, targeted therapies and immunotherapy have improved survival and reduced the morbidity of patients with BRAF‐mutated melanoma. However, drug resistance and relapse hinder overall success. Therefore, there is an urgent need for novel compounds with therapeutic efficacy against BRAF‐melanoma. This prompted us to investigate the antiproliferative profile of a tachykinin‐peptide from the Octopus kaurna , Octpep‐1 in melanoma. We evaluated the cytotoxicity of Octpep‐1 by MTT assay. Mechanistic insights on viability and cellular damage caused by Octpep‐1 were gained via flow cytometry and bioenergetics. Structural and pharmacological characterization was conducted by molecular modelling, molecular biology, CRISPR/Cas9 technology, high‐throughput mRNA and calcium flux analysis. In vivo efficacy was validated in two independent xerograph animal models (mice and zebrafish). Octpep‐1 selectively reduced the proliferative capacity of human melanoma BRAF V600E ‐mutated cells with minimal effects on fibroblasts. In melanoma‐treated cells, Octpep‐1 increased ROS with unaltered mitochondrial membrane potential and promoted non‐mitochondrial and mitochondrial respiration with inefficient ATP coupling. Molecular modelling revealed that the cytotoxicity of Octpep‐1 depends upon the α‐helix and polyproline conformation in the C‐terminal region of the peptide. A truncated form of the C‐terminal end of Octpep‐1 displayed enhanced potency and efficacy against melanoma. Octpep‐1 reduced the progression of tumours in xenograft melanoma mice and zebrafish. We unravel the intrinsic anti‐tumoural properties of a tachykinin peptide. This peptide mediates the selective cytotoxicity in BRAF‐mutated melanoma in vitro and prevents tumour progression in vivo, providing a foundation for a therapy against melanoma.
Publisher: Public Library of Science (PLoS)
Date: 31-08-2011
Publisher: Elsevier BV
Date: 07-2016
DOI: 10.1016/J.CMET.2016.06.010
Abstract: Non-nutritive sweeteners like sucralose are consumed by billions of people. While animal and human studies have demonstrated a link between synthetic sweetener consumption and metabolic dysregulation, the mechanisms responsible remain unknown. Here we use a diet supplemented with sucralose to investigate the long-term effects of sweet/energy imbalance. In flies, chronic sweet/energy imbalance promoted hyperactivity, insomnia, glucose intolerance, enhanced sweet taste perception, and a sustained increase in food and calories consumed, effects that are reversed upon sucralose removal. Mechanistically, this response was mapped to the ancient insulin, catecholamine, and NPF/NPY systems and the energy sensor AMPK, which together comprise a novel neuronal starvation response pathway. Interestingly, chronic sweet/energy imbalance promoted increased food intake in mammals as well, and this also occurs through an NPY-dependent mechanism. Together, our data show that chronic consumption of a sweet/energy imbalanced diet triggers a conserved neuronal fasting response and increases the motivation to eat.
Publisher: Cold Spring Harbor Laboratory
Date: 07-06-2022
DOI: 10.1101/2022.06.07.495067
Abstract: Directed evolution uses cycles of gene ersification and selection to generate proteins with novel properties. While traditionally directed evolution is performed in prokaryotic systems, recently a mammalian directed evolution system (viral evolution of genetically actuating sequences, or “VEGAS”) has been described. Here we report that the VEGAS system has major limitations precluding its use for directed evolution. The primary technical issue with the VEGAS system is an immediate contamination with “cheater” particles that bypass directed evolution circuits. By sequencing we find these cheater particles contain Sindbis structural genes instead of the intended directed evolution target transgene. These cheaters outcompete the VEGAS transgenes within 2 rounds of transduction but cannot themselves activate synthetic circuits that drive expression of Sindbis structural genes, preventing directed evolution c aigns. Similar results have been obtained in independent labs. Taken together, the VEGAS system does not work as described and, without significant redesign to suppress cheaters, cannot be used for mammalian directed evolution c aigns.
Publisher: Cold Spring Harbor Laboratory
Date: 10-11-2021
DOI: 10.1101/2021.11.09.467981
Abstract: Although ACE2 is the primary receptor for SARS-CoV-2 infection, a systematic assessment of host factors that regulate binding to SARS-CoV-2 spike protein has not been described. Here we use whole genome CRISPR activation to identify host factors controlling cellular interactions with SARS-CoV-2. Our top hit was a TLR -related cell surface receptor called leucine-rich repeat-containing protein 15 ( LRRC15 ). LRRC15 expression was sufficient to promote SARS-CoV-2 Spike binding where they form a cell surface complex. LRRC15 mRNA is expressed in human collagen-producing lung myofibroblasts and LRRC15 protein is induced in severe COVID-19 infection where it can be found lining the airways. Mechanistically, LRRC15 does not itself support SARS-CoV-2 infection, but fibroblasts expressing LRRC15 can suppress both pseudotyped and authentic SARS-CoV-2 infection in trans . Moreover, LRRC15 expression in fibroblasts suppresses collagen production and promotes expression of IFIT, OAS, and MX-family antiviral factors. Overall, LRRC15 is a novel SARS-CoV-2 spike-binding receptor that can help control viral load and regulate antiviral and antifibrotic transcriptional programs in the context of COVID-19 infection.
Publisher: Wiley
Date: 10-2021
Abstract: Per‐ and polyfluoroalkyl substances (PFAS) are a large group of manufactured chemicals. Since the beginning of their commercial production in the 1950s, PFAS have not only found their way into numerous industrial and commercial applications, but also into the bloodstream of much of the human population, the natural environment and wildlife. Exposure to high levels of PFAS poses a health risk for humans and animals, and may exacerbate the effects of other anthropogenic impacts faced by wildlife species. To gain a comprehensive overview of the abundance and distribution of PFAS research on wildlife species, and to better understand the drivers of this research, we will collate the available literature into a systematic evidence map and perform bibliometric analyses. The systematic mapping will present the distribution of research evidence that exists on PFAS in wildlife. The bibliometric analysis will provide an insight into the historical trends, interdisciplinarity, connectedness and the impact of the in idual papers. We will conduct a systematic literature search on Scopus, Web of Science and 10 other databases using predefined search strings. We will screen title, abstract and keywords first. We will then screen full‐text papers. Two reviewers will be involved in the screening process. We will only consider publications in English, peer‐reviewed articles, preprints and theses. We will include papers reporting concentrations of any of 34 main PFAS types (based on a previous study) in wild animals. We will assess all publications included in the systematic map for predetermined indicators of quality and potential study‐level biases. In addition, we will use bibliometric records from Scopus to perform impact and network analyses. We will present the results using a narrative summary, tables and colour‐coded maps, bar and network plots. Results and associated database will be available on a dedicated freely accessible website. This study will provide critical insight into the gaps and clusters of the literature with regard to the PFAS concentrations in wildlife. Our study will inform and direct future research efforts to fill the gaps revealed.
Publisher: Springer Science and Business Media LLC
Date: 15-03-2022
Publisher: Elsevier BV
Date: 11-2010
Publisher: The American Association of Immunologists
Date: 06-2009
Abstract: Mac-1-dependent crawling is a new step in the leukocyte recruitment cascade that follows LFA-1-dependent adhesion and precedes emigration. Neutrophil adhesion via LFA-1 has been shown to induce cytoskeletal reorganization through Vav1-dependent signaling, and the current study investigates the role of Vav1 in the leukocyte recruitment process in vivo with particular attention to the events immediately downstream of LFA-1-dependent adhesion. Intravital and spinning-disk-confocal microscopy was used to investigate intravascular crawling in relation to endothelial junctions in vivo in wild-type and Vav1−/− mice. Adherent wild-type neutrophils almost immediately began crawling perpendicular to blood flow via Mac-1 until they reached an endothelial junction where they often changed direction. This pattern of perpendicular, mechanotactic crawling was recapitulated in vitro when shear was applied. In sharp contrast, the movement of Vav1−/− neutrophils was always in the direction of flow and appeared more passive as if the cells were dragged in the direction of flow in vivo and in vitro. More than 80% of Vav1−/− neutrophils moved independent of Mac-1 and could be detached with LFA-1 Abs. An inability to release the uropod was frequently noted for Vav1−/− neutrophils, leading to greatly elongated tails. The Vav1−/− neutrophils failed to stop or follow junctions and ultimately detached, leading to fewer emigrated neutrophils. The Vav1−/− phenotype resulted in fewer neutrophils recruited in a relevant model of infectious peritonitis. Clearly, Vav1 is critical for the complex interplay between LFA-1 and Mac-1 that underlies the programmed intravascular crawling of neutrophils.
Publisher: Research Square Platform LLC
Date: 22-12-2022
DOI: 10.21203/RS.3.RS-2352174/V1
Abstract: Functionally characterizing the genetic alterations that drive pancreatic cancer is a prerequisite for precision medicine. Here, we performed somatic CRISPR/Cas9 mutagenesis screens to assess the transforming potential of 125 recurrently mutated pancreatic cancer genes, which revealed USP15 and SCAF1 as novel pancreatic tumor suppressors. Mechanistically, we found that USP15 functions in a haplo-insufficient manner and that loss of USP15 or SCAF1 leads to reduced inflammatory TNFα, TGF-β and IL6 responses and increased sensitivity to PARP inhibition and Gemcitabine. Furthermore, we found that loss of SCAF1 led to the formation of a truncated, inactive USP15 isoform at the expense of full-length USP15, functionally coupling SCAF1 and USP15. Notably, USP15 and SCAF1 alterations are observed in 31% of pancreatic cancer patients. Our results highlight the utility of in vivo CRISPR screens to integrate human cancer genomics and mouse modeling for the discovery of novel cancer driver genes with potential prognostic and therapeutic implications.
Publisher: Frontiers Media SA
Date: 12-04-2019
Publisher: Public Library of Science (PLoS)
Date: 16-10-2018
Publisher: Springer Science and Business Media LLC
Date: 28-03-2022
DOI: 10.1038/S41467-022-29183-X
Abstract: Carbohydrates, proteins and lipids are essential nutrients to all animals however, closely related species, populations, and in iduals can display dramatic variation in diet. Here we explore the variation in macronutrient tolerance in Drosophila melanogaster using the Drosophila genetic reference panel, a collection of ~200 strains derived from a single natural population. Our study demonstrates that D. melanogaster , often considered a “dietary generalist”, displays marked genetic variation in survival on different diets, notably on high-sugar diet. Our genetic analysis and functional validation identify several regulators of macronutrient tolerance, including CG10960/GLUT8 , Pkn and Eip75B . We also demonstrate a role for the JNK pathway in sugar tolerance and de novo lipogenesis. Finally, we report a role for tailles s, a conserved orphan nuclear hormone receptor, in regulating sugar metabolism via insulin-like peptide secretion and sugar-responsive CCHamide-2 expression. Our study provides support for the use of nutrigenomics in the development of personalized nutrition.
Publisher: The American Association of Immunologists
Date: 15-11-2002
DOI: 10.4049/JIMMUNOL.169.10.5787
Abstract: Granulysin is located in the acidic granules of cytotoxic T cells. Although the purified protein has antimicrobial activity against a broad spectrum of microbial pathogens, direct evidence for granulysin-mediated cytotoxicity has heretofore been lacking. Studies were performed to examine the regulation and activity of granulysin expressed by CD8 T cells using Cryptococcus neoformans, which is one of the most common opportunistic pathogens of AIDS patients. IL-15-activated CD8 T cells acquired anticryptococcal activity, which correlated with the up-regulation of granulysin. When granules containing granulysin were depleted using SrCl2, or when the gene was silenced using 21-nt small interfering RNA duplexes, the antifungal effect of CD8 T cells was abrogated. Concanamycin A and EGTA did not affect the antifungal effect, suggesting that the activity of granulysin was perforin independent. Following stimulation by the C. neoformans mitogen, CD8 T cells expressed granulysin and acquired antifungal activity. This activity required CD4 T cells and was dependent upon accessory cells. Furthermore, IL-15 was both necessary and sufficient for granulysin up-regulation in CD8 T cells. These observations are most consistent with a mechanism whereby C. neoformans mitogen is presented to CD4 T cells, which in turn activate accessory cells. The resultant IL-15 activates CD8 T cells to express granulysin, which is responsible for antifungal activity.
Publisher: Elsevier BV
Date: 11-2007
DOI: 10.1016/J.CELL.2007.08.047
Abstract: Type-2 diabetes results from the development of insulin resistance and a concomitant impairment of insulin secretion. Recent studies place altered mitochondrial oxidative phosphorylation (OxPhos) as an underlying genetic element of insulin resistance. However, the causative or compensatory nature of these OxPhos changes has yet to be proven. Here, we show that muscle- and liver-specific AIF ablation in mice initiates a pattern of OxPhos deficiency closely mimicking that of human insulin resistance, and contrary to current expectations, results in increased glucose tolerance, reduced fat mass, and increased insulin sensitivity. These results are maintained upon high-fat feeding and in both genetic mosaic and ubiquitous OxPhos-deficient mutants. Importantly, the effects of AIF on glucose metabolism are acutely inducible and reversible. These findings establish that tissue-specific as well as global OxPhos defects in mice can counteract the development of insulin resistance, diabetes, and obesity.
Publisher: The American Association of Immunologists
Date: 11-2001
DOI: 10.4049/JIMMUNOL.167.9.5011
Abstract: Although IL-15 shares many of the biological activities of IL-2, IL-2 expression is primarily under transcriptional regulation, while the mechanisms involved in the regulation of IL-15 are complex and not completely understood. In the current study, we found that CD14+ monocytes constitutively exhibit both IL-15 mRNA and protein. IL-15 protein was found stored intracellularly and stimulation of CD14+ monocytes with either LPS or GM-CSF resulted in mobilization of IL-15 stores to the plasma membrane. This rapidly induced surface expression was the result of a translocation of preformed stores, confirming that posttranslational regulatory stages limit IL-15, because it was not accompanied by an increase in IL-15 mRNA and occurred independent of de novo protein synthesis. After fixation, activated monocytes, but not resting monocytes, were found to support T cell proliferation, and this effect was abrogated by the addition of an IL-15-neutralizing Ab. The presence of preformed IL-15 stores and the ability of stimulated monocytes to mobilize these stores to their surface in an active form is a novel mechanism of regulation for IL-15.
Publisher: Hindawi Limited
Date: 2008
DOI: 10.1155/2008/849745
Abstract: Zinc oxide nanowires, nanobelts, and nanoneedles were synthesized using the vapor-liquid-solid technique. Young's modulus of the nanowires was measured by performing cantilever bending experiments on in idual nanowires in situ inside a scanning electron microscope. The nanowires tested had diameters in the range of 200–750 nm. The average Young's modulus, measured to be 40 GPa, is about 30% of that reported at the bulk scale. The experimental results are discussed in light of the pronounced electromechanical coupling due to the piezoelectric nature of the material.
Publisher: Public Library of Science (PLoS)
Date: 09-02-2023
DOI: 10.1371/JOURNAL.PBIO.3001967
Abstract: Although ACE2 is the primary receptor for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection, a systematic assessment of host factors that regulate binding to SARS-CoV-2 spike protein has not been described. Here, we use whole-genome CRISPR activation to identify host factors controlling cellular interactions with SARS-CoV-2. Our top hit was a TLR -related cell surface receptor called leucine-rich repeat-containing protein 15 ( LRRC15 ). LRRC15 expression was sufficient to promote SARS-CoV-2 spike binding where they form a cell surface complex. LRRC15 mRNA is expressed in human collagen-producing lung myofibroblasts and LRRC15 protein is induced in severe Coronavirus Disease 2019 (COVID-19) infection where it can be found lining the airways. Mechanistically, LRRC15 does not itself support SARS-CoV-2 infection, but fibroblasts expressing LRRC15 can suppress both pseudotyped and authentic SARS-CoV-2 infection in trans . Moreover, LRRC15 expression in fibroblasts suppresses collagen production and promotes expression of IFIT, OAS, and MX-family antiviral factors. Overall, LRRC15 is a novel SARS-CoV-2 spike-binding receptor that can help control viral load and regulate antiviral and antifibrotic transcriptional programs in the context of COVID-19 infection.
Publisher: Public Library of Science (PLoS)
Date: 06-07-2015
Publisher: Shared Science Publishers OG
Date: 10-09-2018
Publisher: Oxford University Press (OUP)
Date: 09-10-2020
Abstract: Poor sleep quality can have harmful health consequences. Although many aspects of sleep are heritable, the understandings of genetic factors involved in its physiology remain limited. Here, we performed a genome-wide association study (GWAS) using the Pittsburgh Sleep Quality Index (PSQI) in a multi-ethnic discovery cohort (n = 2868) and found two novel genome-wide loci on chromosomes 2 and 7 associated with global sleep quality. A meta-analysis in 12 independent cohorts (100 000 in iduals) replicated the association on chromosome 7 between NPY and MPP6. While NPY is an important sleep gene, we tested for an independent functional role of MPP6. Expression data showed an association of this locus with both NPY and MPP6 mRNA levels in brain tissues. Moreover, knockdown of an orthologue of MPP6 in Drosophila melanogaster sleep center neurons resulted in decreased sleep duration. With convergent evidence, we describe a new locus impacting human variability in sleep quality through known NPY and novel MPP6 sleep genes.
Publisher: Frontiers Media SA
Date: 20-12-2019
Publisher: Elsevier BV
Date: 06-2017
Publisher: Springer Science and Business Media LLC
Date: 07-02-2020
DOI: 10.1186/S13059-020-1940-8
Abstract: Drug resistance is a major obstacle in cancer therapy. To elucidate the genetic factors that regulate sensitivity to anti-cancer drugs, we performed CRISPR-Cas9 knockout screens for resistance to a spectrum of drugs. In addition to known drug targets and resistance mechanisms, this study revealed novel insights into drug mechanisms of action, including cellular transporters, drug target effectors, and genes involved in target-relevant pathways. Importantly, we identified ten multi-drug resistance genes, including an uncharacterized gene C1orf115 , which we named Required for Drug-induced Death 1 ( RDD1 ). Loss of RDD1 resulted in resistance to five anti-cancer drugs. Finally, targeting RDD1 leads to chemotherapy resistance in mice and low RDD1 expression is associated with poor prognosis in multiple cancers. Together, we provide a functional landscape of resistance mechanisms to a broad range of chemotherapeutic drugs and highlight RDD1 as a new factor controlling multi-drug resistance. This information can guide personalized therapies or instruct rational drug combinations to minimize acquisition of resistance.
Publisher: Springer Science and Business Media LLC
Date: 19-02-2022
DOI: 10.1038/S41388-022-02223-Y
Abstract: Oncogenic mutations in the small GTPase RAS contribute to ~30% of human cancers. In a Drosophila genetic screen, we identified novel and evolutionary conserved cancer genes that affect Ras-driven tumorigenesis and metastasis in Drosophila including confirmation of the tetraspanin Tsp29Fb. However, it was not known whether the mammalian Tsp29Fb orthologue, TSPAN6, has any role in RAS-driven human epithelial tumors. Here we show that TSPAN6 suppressed tumor growth and metastatic dissemination of human RAS activating mutant pancreatic cancer xenografts. Whole-body knockout as well as tumor cell autonomous inactivation using floxed alleles of Tspan6 in mice enhanced Kras G12D -driven lung tumor initiation and malignant progression. Mechanistically, TSPAN6 binds to the EGFR and blocks EGFR-induced RAS activation. Moreover, we show that inactivation of TSPAN6 induces an epithelial-to-mesenchymal transition and inhibits cell migration in vitro and in vivo. Finally, low TSPAN6 expression correlates with poor prognosis of patients with lung and pancreatic cancers with mesenchymal morphology. Our results uncover TSPAN6 as a novel tumor suppressor receptor that controls epithelial cell identify and restrains RAS-driven epithelial cancer.
Publisher: F1000 Research Ltd
Date: 23-01-2018
DOI: 10.12688/F1000RESEARCH.13581.1
Abstract: Background : Paclitaxel-induced peripheral neuropathy is a common and limiting side effect of an approved and effective chemotherapeutic agent. The cause of this nociception is still unknown. Methods : To uncover the mechanism involved in paclitaxel-induced pain, we developed a Drosophila thermal nociceptive model to show the effects of paclitaxel exposure on third instar larvae. Results : We found that paclitaxel increases pain perception in a dose-dependent manner, without overt morphological changes. Conclusions : Our simple, high throughput model can be combined with genomics approaches to identify regulators of chemotherapy-induced pain to eliminate its adverse side effects.
Publisher: Wiley
Date: 21-06-2019
DOI: 10.1002/ANA.25521
Abstract: Heightened somatic symptoms are reported by a wide range of patients with chronic pain and have been associated with emotional distress and physical dysfunction. Despite their clinical significance, molecular mechanisms leading to their manifestation are not understood. We used an association study design based on a curated list of 3,295 single nucleotide polymorphisms mapped to 358 genes to test somatic symptoms reporting using the Pennebaker Inventory of Limbic Languidness questionnaire from a case-control cohort of orofacial pain (n = 1,607). A replication meta-analysis of 3 independent cohorts (n = 3,189) was followed by functional validation, including in silico molecular dynamics, in vitro enzyme assays, and measures of serotonin (5-HT) plasma concentration. An association with the T allele of rs11575542 coding for an arginine to glutamine substitution in the L-aromatic amino acid decarboxylase (AADC) enzyme was replicated in a meta-analysis of 3 independent cohorts. In a combined meta-analysis of all cohorts, this association reached p = 6.43 × 10 Using functional genomics approaches, we identified a polymorphism in the AADC enzyme that contributes to somatic symptoms through reduced levels of 5-HT. Our findings suggest a molecular mechanism underlying the pathophysiology of somatic symptoms and opens up new treatment options targeting the serotonergic system. ANN NEUROL 2019 :168-180.
Publisher: F1000 Research Ltd
Date: 16-10-2018
DOI: 10.12688/F1000RESEARCH.13581.2
Abstract: Background : Paclitaxel-induced peripheral neuropathy is a common and limiting side effect of an approved and effective chemotherapeutic agent. The cause of this nociception is still unknown. Methods : To uncover the mechanism involved in paclitaxel-induced pain, we developed a Drosophila thermal nociceptive model to show the effects of paclitaxel exposure on third instar larvae. Results : We found that paclitaxel increases heat nociception in a dose-dependent manner, and at the highest doses also obstructs dendritic repulsion cues. Conclusions : Our simple system can be applied to identify regulators of chemotherapy-induced pain and may help to eliminate pain-related side-effects of chemotherapy.
Publisher: Informa UK Limited
Date: 17-06-2015
Publisher: Elsevier BV
Date: 04-2010
Publisher: American Association for the Advancement of Science (AAAS)
Date: 05-07-2019
Abstract: Nerve injury leads to loss of central inhibition and neuropathic pain in the fruit fly.
Publisher: Cold Spring Harbor Laboratory
Date: 05-12-2022
DOI: 10.1101/2022.12.05.518134
Abstract: Widescale evidence points to the involvement of glia and immune pathways in the progression of Alzheimer’s disease (AD). AD-associated iPSC-derived glial cells show a erse range of AD-related phenotypic states encompassing cytokine/chemokine release, phagocytosis and morphological profiles, but to date studies are limited to cells derived from PSEN1, APOE and APP mutations or sporadic patients. The aim of the current study was to successfully differentiate iPSC-derived microglia and astrocytes from patients harbouring an AD-causative PSEN2 (N141I) mutation and characterise the inflammatory and morphological profile of these cells. iPSCs from three healthy control in iduals and three familial AD patients harbouring a heterozygous PSEN2 (N141I) mutation were used to derive astrocytes and microglia-like cells and cell identity and morphology were characterised through immunofluorescent microscopy. Cellular characterisation involved the stimulation of these cells by LPS and Aβ 42 and analysis of cytokine/chemokine release was conducted through ELISAs and multi-cytokine arrays. The phagocytic capacity of these cells was then indexed by the uptake of fluorescently labelled fibrillar Aβ 42 . AD-derived astrocytes and microglia-like cells exhibited an atrophied and less complex morphological appearance than healthy controls. AD-derived astrocytes showed increased basal expression of GFAP, S100β and increased secretion and phagocytosis of Aβ 42 while AD-derived microglia-like cells showed decreased IL-8 secretion compared to healthy controls. Upon immunological challenge AD-derived astrocytes and microglia-like cells show exaggerated secretion of the pro-inflammatory IL-6, CXCL1, ICAM-1 and IL-8 from astrocytes and IL-18 and MIF from microglia. Our study showed, for the first time, the differentiation and characterisation of iPSC-derived astrocytes and microglia-like cells harbouring a PSEN2 (N141I) mutation. PSEN2 (N141I)-mutant astrocytes and microglia-like cells presented with a ‘primed’ phenotype characterised by reduced morphological complexity, exaggerated pro-inflammatory cytokine secretion and altered Aβ 42 production and phagocytosis.
Publisher: MDPI AG
Date: 19-01-2023
DOI: 10.3390/IJMS24031984
Abstract: Autosomal dominant mutations in the gene encoding α-synuclein (SNCA) were the first to be linked with hereditary Parkinson’s disease (PD). Duplication and triplication of SNCA has been observed in PD patients, together with mutations at the N-terminal of the protein, among which A30P and A53T influence the formation of fibrils. By overexpressing human α-synuclein in the neuronal system of Drosophila, we functionally validated the ability of IP3K2, an ortholog of the GWAS identified risk gene, Inositol-trisphosphate 3-kinase B (ITPKB), to modulate α-synuclein toxicity in vivo. ITPKB mRNA and protein levels were also increased in SK-N-SH cells overexpressing wild-type α-synuclein, A53T or A30P mutants. Kinase overexpression was detected in the cytoplasmatic and in the nuclear compartments in all α-synuclein cell types. By quantifying mRNAs in the cortex of PD patients, we observed higher levels of ITPKB mRNA when SNCA was expressed more (p 0.05), compared to controls. A positive correlation was also observed between SNCA and ITPKB expression in the cortex of patients, which was not seen in the controls. We replicated this observation in a public dataset. Our data, generated in SK-N-SH cells and in cortex from PD patients, show that the expression of α-synuclein and ITPKB is correlated in pathological situations.
Publisher: American Thoracic Society
Date: 02-2008
Publisher: Public Library of Science (PLoS)
Date: 06-12-2012
Publisher: American Society for Clinical Investigation
Date: 15-04-2022
DOI: 10.1172/JCI151817
Publisher: Elsevier BV
Date: 11-2019
Publisher: The American Association of Immunologists
Date: 15-11-2002
DOI: 10.4049/JIMMUNOL.169.10.5679
Abstract: Soluble GM-CSF receptor α subunit (sGMRα) is a soluble isoform of the GMRα that is believed to arise exclusively through alternative splicing of the GMRα gene product. The sGMRα mRNA is expressed in a variety of tissues, but it is not clear which cells are capable of secreting the protein. We show here that normal human monocytes, but not lymphocytes, constitutively secrete sGMRα. Stimulation of monocytes with GM-CSF, LPS, PMA, or A23187 rapidly up-regulates the secretion of sGMRα in a dose-dependent manner, demonstrating that secretion is also regulated. To determine whether sGMRα arose exclusively through alternative splicing of the GMRα gene product, or whether it could also be generated through ectodomain shedding of GMRα, we engineered a murine pro-B cell line (Ba/F3) to express exclusively the cDNA for cell surface GMRα (Ba/F3.GMRα). The Ba/F3.GMRα cell line, but not the parental Ba/F3 cell line, constitutively shed a sGMRα-like protein that bound specifically to GM-CSF, was equivalent in size to recombinant alternatively spliced sGMRα (60 kDa), and was recognized specifically by a mAb raised against the ectodomain of GMRα. Furthermore, a broad-spectrum metalloprotease inhibitor (BB94) reduced constitutive and PMA-, A23187-, and LPS-induced secretion of sGMRα by monocytes, suggesting that shedding of GMRα by monocytes may be mediated in part through the activity of metalloproteases. Taken together, these observations demonstrate that sGMRα is constitutively secreted by monocytes, that GM-CSF and inflammatory mediators up-regulate sGMRα secretion, and that sGMRα arises not only through alternative splicing but also through ectodomain shedding of cell surface GMRα.
Publisher: Cold Spring Harbor Laboratory
Date: 14-02-2023
DOI: 10.1101/2023.02.13.528235
Abstract: COVID-19 causes a clinical spectrum of acute and chronic illness and host / virus interactions are not completely understood 1,2 . To identify host factors that can influence SARS-CoV-2 infection, we screened the human genome for genes that, when upregulated, alter the outcome of authentic SARS-CoV-2 infection. From this, we identify 34 new genes that can alter the course of infection, including the innate immune receptor P-selectin, which we show is a novel SARS-CoV-2 spike receptor. At the cellular level expression of P-selectin does not confer tropism for SARS-CoV-2, instead it acts to suppress infection. More broadly, P-selectin can also promote binding to SARS-CoV-2 variants, SARS-CoV-1 and MERS, acting as a general spike receptor for highly pathogenic coronaviruses. P-selectin is expressed on platelets and endothelium 3 , and we confirm SARS-CoV-2 spike interactions with these cells are P-selectin-dependent and can occur under shear flow conditions. In vivo , authentic SARS-CoV-2 uses P-selectin to home to airway capillary beds where the virus interacts with the endothelium and platelets, and blocking this interaction can clear vascular-associated SARS-CoV-2 from the lung. Together we show for the first time that coronaviruses can use the leukocyte recruitment system to control tissue localization, and this fundamental insight may help us understand and control highly pathogenic coronavirus disease progression.
Publisher: Society for Neuroscience
Date: 14-09-2020
DOI: 10.1523/JNEUROSCI.0349-20.2020
Abstract: Within mammalian brain circuits, activity-dependent synaptic adaptations, such as synaptic scaling, stabilize neuronal activity in the face of perturbations. Stability afforded through synaptic scaling involves uniform scaling of quantal litudes across all synaptic inputs formed on neurons, as well as on the postsynaptic side. It remains unclear whether activity-dependent uniform scaling also operates within peripheral circuits. We tested for such scaling in a Drosophila larval neuromuscular circuit, where the muscle receives synaptic inputs from different motoneurons. We used motoneuron-specific genetic manipulations to increase the activity of only one motoneuron and recordings of postsynaptic currents from inputs formed by the different motoneurons. We discovered an adaptation which caused uniform downscaling of evoked neurotransmitter release across all inputs through decreases in release probabilities. This “presynaptic downscaling” maintained the relative differences in neurotransmitter release across all inputs around a homeostatic set point, caused a compensatory decrease in synaptic drive to the muscle affording robust and stable muscle activity, and was induced within hours. Presynaptic downscaling was associated with an activity-dependent increase in Drosophila vesicular glutamate transporter expression. Activity-dependent uniform scaling can therefore manifest also on the presynaptic side to produce robust and stable circuit outputs. Within brain circuits, uniform downscaling on the postsynaptic side is implicated in sleep- and memory-related processes. Our results suggest that evaluation of such processes might be broadened to include uniform downscaling on the presynaptic side. SIGNIFICANCE STATEMENT To date, compensatory adaptations which stabilise target cell activity through activity-dependent global scaling have been observed only within central circuits, and on the postsynaptic side. Considering that maintenance of stable activity is imperative for the robust function of the nervous system as a whole, we tested whether activity-dependent global scaling could also manifest within peripheral circuits. We uncovered a compensatory adaptation which causes global scaling within a peripheral circuit and on the presynaptic side through uniform downscaling of evoked neurotransmitter release. Unlike in central circuits, uniform scaling maintains functionality over a wide, rather than a narrow, operational range, affording robust and stable activity. Activity-dependent global scaling therefore operates on both the presynaptic and postsynaptic sides to maintain target cell activity.
Publisher: Springer Science and Business Media LLC
Date: 13-02-2011
DOI: 10.1038/NG.767
Abstract: Most preneoplastic lesions are quiescent and do not progress to form overt tumors. It has been proposed that oncogenic stress activates the DNA damage response and the key tumor suppressor p53, which prohibits tumor growth. However, the molecular pathways by which cells sense a premalignant state in vivo are largely unknown. Here we report that tissue-specific inactivation of the stress signaling kinase MKK7 in KRas(G12D)-driven lung carcinomas and NeuT-driven mammary tumors markedly accelerates tumor onset and reduces overall survival. Mechanistically, MKK7 acts through the kinases JNK1 and JNK2, and this signaling pathway directly couples oncogenic and genotoxic stress to the stability of p53, which is required for cell cycle arrest and suppression of epithelial cancers. These results show that MKK7 functions as a major tumor suppressor in lung and mammary cancer in mouse and identify MKK7 as a vital molecular sensor to set a cellular anti-cancer barrier.
Publisher: Springer Science and Business Media LLC
Date: 02-12-2019
DOI: 10.1038/S41467-019-13114-4
Abstract: Protein oxidation sits at the intersection of multiple signalling pathways, yet the magnitude and extent of crosstalk between oxidation and other post-translational modifications remains unclear. Here, we delineate global changes in adipocyte signalling networks following acute oxidative stress and reveal considerable crosstalk between cysteine oxidation and phosphorylation-based signalling. Oxidation of key regulatory kinases, including Akt, mTOR and AMPK influences the fidelity rather than their absolute activation state, highlighting an unappreciated interplay between these modifications. Mechanistic analysis of the redox regulation of Akt identified two cysteine residues in the pleckstrin homology domain (C60 and C77) to be reversibly oxidized. Oxidation at these sites affected Akt recruitment to the plasma membrane by stabilizing the PIP 3 binding pocket. Our data provide insights into the interplay between oxidative stress-derived redox signalling and protein phosphorylation networks and serve as a resource for understanding the contribution of cellular oxidation to a range of diseases.
Publisher: Elsevier BV
Date: 05-2019
Publisher: Informa UK Limited
Date: 02-10-2015
Publisher: Wiley
Date: 27-08-2013
DOI: 10.1111/FEBS.12464
Abstract: Chronic pain represents a significant public health concern and current therapies do not adequately meet patient needs. With the advent of genomic technologies, pain researchers have begun to identify key loci associating with human pain diseases, and these data are instructing the development of next generation analgesics. Although human genetics efforts have been effective, complementary approaches, including functional genomics, may provide additional insight into pain genetics and help identify additional new drug targets. In the present review, we discuss the use of fruit fly systems biology combined with mammalian genetics to accelerate the discovery of novel pain genes and candidate drug targets.
Publisher: The Royal Society
Date: 23-09-2019
Abstract: Nerve injury leads to devastating and often untreatable neuropathic pain. While acute noxious sensation (nociception) is a crucial survival mechanism and is conserved across phyla, chronic neuropathic pain is considered a maladaptive response owing to its devastating impact on a patient's quality of life. We have recently shown that a neuropathic pain-like response occurs in adult Drosophila . However, the mechanisms underlying this phenomenon are largely unknown. Previous studies have shown that the α2δ peripheral calcium channel subunit straightjacket ( stj ) is a conserved factor required for thermal pain perception. We demonstrate here that stj is required in peripheral ppk+ sensory neurons for acute thermal responses and that it mediates nociceptive hypersensitivity in an adult Drosophila model of neuropathic pain-like disease. Given that calcium channels are the main targets of gabapentinoids (pregabalin and gabapentin), we assessed if these drugs can alleviate nociceptive hypersensitivity. Our findings suggest that gabapentinoids may prevent nociceptive hypersensitivity by preserving central inhibition after nerve injury. Together, our data further highlight the similarity of some mechanisms for pain-like conditions across phyla and validates the scientific use of Drosophila neuropathic sensitization models for analgesic drug discovery. This article is part of the Theo Murphy meeting issue ‘Evolution of mechanisms and behaviour important for pain’.
Publisher: Wiley
Date: 22-08-2012
DOI: 10.1111/J.1399-0004.2012.01941.X
Abstract: Survival of all animals depends on an accurate representation of the world, and an organism must be capable of prioritizing and responding to potentially hazardous conditions. This ability is dependent on nociception, the sensory process allowing animals to detect and avoid potentially harmful stimuli. Nociception is the sensory process that results in the subjective experience of 'pain' in humans. Because of its vital and broad role in animal biology, pain/nociception is a complex, whole-body physiological process that is under stringent evolutionary pressure. Here, we discuss the utility of Drosophila melanogaster as an emerging model organism for studying the conserved genetics of nociception, particularly with respect to recently developed high-throughput Drosophila 'pain' paradigms.
Publisher: Springer Science and Business Media LLC
Date: 30-04-2019
DOI: 10.1038/S41467-019-09681-1
Abstract: The box jellyfish Chironex fleckeri is extremely venomous, and envenoming causes tissue necrosis, extreme pain and death within minutes after severe exposure. Despite rapid and potent venom action, basic mechanistic insight is lacking. Here we perform molecular dissection of a jellyfish venom-induced cell death pathway by screening for host components required for venom exposure-induced cell death using genome-scale lenti-CRISPR mutagenesis. We identify the peripheral membrane protein ATP2B1, a calcium transporting ATPase, as one host factor required for venom cytotoxicity. Targeting ATP2B1 prevents venom action and confers long lasting protection. Informatics analysis of host genes required for venom cytotoxicity reveal pathways not previously implicated in cell death. We also discover a venom antidote that functions up to 15 minutes after exposure and suppresses tissue necrosis and pain in mice. These results highlight the power of whole genome CRISPR screening to investigate venom mechanisms of action and to rapidly identify new medicines.
Publisher: Public Library of Science (PLoS)
Date: 14-12-2021
DOI: 10.1371/JOURNAL.PGEN.1009962
Abstract: TM2 domain containing (TM2D) proteins are conserved in metazoans and encoded by three separate genes in each model organism species that has been sequenced. Rare variants in TM2D3 are associated with Alzheimer’s disease (AD) and its fly ortholog almondex is required for embryonic Notch signaling. However, the functions of this gene family remain elusive. We knocked-out all three TM2D genes ( almondex , CG11103/amaretto , CG10795/biscotti ) in Drosophila and found that they share the same maternal-effect neurogenic defect. Triple null animals are not phenotypically worse than single nulls, suggesting these genes function together. Overexpression of the most conserved region of the TM2D proteins acts as a potent inhibitor of Notch signaling at the γ-secretase cleavage step. Lastly, Almondex is detected in the brain and its loss causes shortened lifespan accompanied by progressive motor and electrophysiological defects. The functional links between all three TM2D genes are likely to be evolutionarily conserved, suggesting that this entire gene family may be involved in AD.
Publisher: The American Association of Immunologists
Date: 08-2004
DOI: 10.4049/JIMMUNOL.173.3.2031
Abstract: Some bacterial products possess multiple immunomodulatory effects and thereby complex mechanisms of action. Exogenous administration of an important Pseudomonas aeruginosa virulence factor, exoenzyme S (ExoS) induces potent monocyte activation leading to the production of numerous proinflammatory cytokines and chemokines. However, ExoS is also injected directly into target cells, inducing cell death through its multiple effects on signaling pathways. This study addresses the mechanisms used by ExoS to induce monocyte activation. Exogenous administration resulted in specific internalization of ExoS via an actin-dependent mechanism. However, ExoS-mediated cellular activation was not inhibited if internalization was blocked, suggesting an alternate mechanism of activation. ExoS bound a saturable and specific receptor on the surface of monocytic cells. ExoS, LPS, and peptidoglycan were all able to induce tolerance and cross-tolerance to each other suggesting the involvement of a TLR in ExoS-recognition. ExoS activated monocytic cells via a myeloid differentiation Ag-88 pathway, using both TLR2 and the TLR4/MD-2/CD14 complex for cellular activation. Interestingly, the TLR2 activity was localized to the C-terminal domain of ExoS while the TLR4 activity was localized to the N-terminal domain. This study provides the first ex le of how different domains of the same molecule activate two TLRs, and also highlights the possible overlapping pathophysiological processes possessed by microbial toxins.
Publisher: The American Association of Immunologists
Date: 09-2004
DOI: 10.4049/JIMMUNOL.173.5.3357
Abstract: Cytotoxic lymphocytes have the capacity to kill microbes directly however, the mechanisms involved are poorly understood. Using Cryptococcus neoformans, which causes a potentially fatal fungal infection in HIV-infected patients, our previous studies showed that granulysin is necessary, while perforin is dispensable, for CD8 T lymphocyte fungal killing. By contrast, the mechanisms by which NK cells exert their antimicrobial activity are not clear, and in particular, the contribution of granulysin and perforin to NK-mediated antifungal activity is unknown. Primary human NK cells and a human NK cell line YT were found to constitutively express granulysin and perforin, and possessed anticryptococcal activity, in contrast to CD8 T lymphocytes, which required stimulation. When granulysin protein and mRNA were blocked by granulysin small interfering RNA, the NK cell-mediated antifungal effect was not affected in contrast to the abrogated activity observed in CD8 T lymphocytes. However, when perforin was inhibited by concanamycin A, and silenced using hairpin small interfering RNA, the anticryptococcal activities of NK cells were abrogated. Furthermore, when granulysin and perforin were both inhibited, the anticryptococcal activities of the NK cells were not reduced further than by silencing perforin alone. These results indicate that the antifungal activity is constitutively expressed in NK cells in contrast to CD8 T lymphocytes, in which it requires prior activation, and perforin, but not granulysin, plays the dominant role in NK cell anticryptococcal activity, in contrast to CD8 T lymphocytes, in which granulysin, but not perforin, plays the dominant role in anticryptococcal activity.
Publisher: Elsevier BV
Date: 08-2017
DOI: 10.1016/J.CUB.2017.07.022
Abstract: The gut microbiota affects a wide spectrum of host physiological traits, including development [1-5], germline [6], immunity [7-9], nutrition [4, 10, 11], and longevity [12, 13]. Association with microbes also influences fitness-related behaviors such as mating [14] and social interactions [15, 16]. Although the gut microbiota is evidently important for host wellbeing, how hosts become associated with particular assemblages of microbes from the environment remains unclear. Here, we present evidence that the gut microbiota can modify microbial and nutritional preferences of Drosophila melanogaster. By experimentally manipulating the gut microbiota of flies subjected to behavioral and chemosensory assays, we found that fly-microbe attractions are shaped by the identity of the host microbiota. Conventional flies exhibit preference for their associated Lactobacillus, a behavior also present in axenic flies as adults and marginally as larvae. By contrast, fly preference for Acetobacter is primed by early-life exposure and can override the innate preference. These microbial preferences are largely olfactory guided and have profound impact on host foraging, as flies continuously trade off between acquiring beneficial microbes and balancing nutrients from food. Our study shows a role of animal microbiota in shaping host fitness-related behavior through their chemosensory responses, opening a research theme on the interrelationships between the microbiota, host sensory perception, and behavior.
Publisher: Elsevier BV
Date: 2010
DOI: 10.1016/J.CELL.2009.12.027
Abstract: Over 1 billion people are estimated to be overweight, placing them at risk for diabetes, cardiovascular disease, and cancer. We performed a systems-level genetic dissection of adiposity regulation using genome-wide RNAi screening in adult Drosophila. As a follow-up, the resulting approximately 500 candidate obesity genes were functionally classified using muscle-, oenocyte-, fat-body-, and neuronal-specific knockdown in vivo and revealed hedgehog signaling as the top-scoring fat-body-specific pathway. To extrapolate these findings into mammals, we generated fat-specific hedgehog-activation mutant mice. Intriguingly, these mice displayed near total loss of white, but not brown, fat compartments. Mechanistically, activation of hedgehog signaling irreversibly blocked differentiation of white adipocytes through direct, coordinate modulation of early adipogenic factors. These findings identify a role for hedgehog signaling in white/brown adipocyte determination and link in vivo RNAi-based scanning of the Drosophila genome to regulation of adipocyte cell fate in mammals.
Publisher: American Chemical Society (ACS)
Date: 11-10-2022
DOI: 10.1021/ACSSYNBIO.2C00460
Abstract: Directed evolution uses cycles of gene ersification and selection to generate proteins with novel properties. While traditionally directed evolution is performed in prokaryotic systems, recently a mammalian directed evolution system (viral evolution of genetically actuating sequences, or "VEGAS") has been described. Here we report that the VEGAS system has major limitations that preclude its use for directed evolution. The deconstructed Sindbis virus (SINV) genome that comprises the VEGAS system could no longer promote Sindbis structural gene (SSG)-dependent viral replication. Moreover, viral particles generated using the VEGAS system rapidly lost the target directed evolution transgene, and instead, "cheater" particles, primarily containing RNA encoding SINV structural components, arose. By sequencing, we found that this contamination came from RNA provided during initial SINV packaging, not RNA derived from the VEGAS system. Of note, both the structural RNA and target transgenes used in the VEGAS system contain viral packaging sequences. The impact of SINV "cheater" particles could be potentially overcome in the context of a robust VEGAS circuit, but since SSG complementation is also defective in the VEGAS system, selection for authentic evolution products is not currently possible. Similar results have been obtained in independent laboratories. Taken together, these results show that the VEGAS system does not work as described and, without significant redesign, cannot be used for mammalian directed evolution c aigns.
Publisher: Elsevier BV
Date: 2022
Publisher: American Society for Microbiology
Date: 08-2000
DOI: 10.1128/IAI.68.8.4811-4814.2000
Abstract: Pseudomonas aeruginosa infection of cystic fibrosis patients causes lung damage that is substantially orchestrated by cytokines. In this study, multi-gene probe analysis was used to characterize the ability of the P. aeruginosa mitogen, exoenzyme S, to induce proinflammatory and immunoregulatory cytokines and chemokines. Exoenzyme S strongly induced transcription of proinflammatory cytokines and chemokines (tumor necrosis factor alpha, interleukin-1α [IL-1α], IL-1β, IL-6, IL-8, MIP-1α, MIP-1β, MCP-1, RANTES, and I-309), modest transcription of immunoregulatory cytokines (IL-10 and IL-12p40), and weak transcription of Th1 cytokines (IL-2 and gamma interferon). The response occurred early and subsided without evolving over time. These data suggest that cells responding to exoenzyme S would rapidly express proinflammatory cytokines and chemokines that may contribute to pulmonary inflammation in cystic fibrosis.
Publisher: Elsevier BV
Date: 12-2017
Start Date: 03-2022
End Date: 03-2025
Amount: $528,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2022
End Date: 12-2024
Amount: $568,152.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2021
End Date: 12-2021
Amount: $900,000.00
Funder: Australian Research Council
View Funded Activity