25 research outputs found

    Characterisation of Australian Staphylococcus aureus isolates of bovine mastitis origin, and development and evaluation of the potential of vaccines for prevention of mastitis using mouse as a model system

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    Serological typing was demonstrated to be more reliable than molecular typing for capsular phenotyping of Australian bovine mastitis-associated Staphylococcus aureus isolates. A relationship between strength of biofilm formation, icaA and icaD genes and extent of mammary tissue damage was apparent. Distribution of MSCRAMMs and exotoxins, and potential of anti-IL6 and anti IL6-receptor antibodies on mortality of infected mice was determined. Biofilm-embedded S. aureus vaccine offered better protection against mammary tissue damage than the planktonic vaccine

    Diversity of virulence factors associated with West Australian methicillin-sensitive staphylococcus aureus isolates of human origin

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    An extensive array of virulence factors associated with S. aureus has contributed significantly to its success as a major nosocomial pathogen in hospitals and community causing variety of infections in affected patients. Virulence factors include immune evading capsular polysaccharides, poly-N-acetyl glucosamine, and teichoic acid in addition to damaging toxins including hemolytic toxins, enterotoxins, cytotoxins, exfoliative toxin, and microbial surface components recognizing adhesive matrix molecules (MSCRAMM). In this investigation, 31 West Australian S. aureus isolates of human origin and 6 controls were analyzed for relative distribution of virulence-associated genes using PCR and/or an immunoassay kit and MSCRAMM by PCR-based typing. Genes encoding MSCRAMM, namely, Spa, ClfA, ClfB, SdrE, SdrD, IsdA, and IsdB, were detected in >90% of isolates. Gene encoding a-toxin was detected in >90% isolates whereas genes encoding ß-toxin and SEG were detectable in 50-60% of isolates. Genes encoding toxin proteins, namely, SEA, SEB, SEC, SED, SEE, SEH, SEI, SEJ, TSST, PVL, ETA, and ETB, were detectable in >50% of isolates. Use of RAPD-PCR for determining the virulence factor-based genetic relatedness among the isolates revealed five cluster groups confirming genetic diversity among the MSSA isolates, with the greatest majority of the clinical S. aureus (84%) isolates clustering in group IIIa

    Wnt/B-Catenin signalling during liver metabolism, chronic liver disease and hepatocarcinogenesis

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    Chronic liver diseases (CLDs) are increasing in prevalence and their end-stage complications, namely, cirrhosis, liver failure and hepatocellular carcinoma represent major global challenges. The most common initiators of progressive CLD are viral hepatitis and long-term alcohol abuse as well as steatosis and steatohepatitis. Irrespective of the underlying aetiology, a common feature of CLD is the formation of hepatic ductular reactions, involving the proliferation of liver progenitor cells (LPCs) and their sig­nalling to fibrosis-driving hepatic stellate cells. The Wnt/β-catenin pathway has been found to regulate development, stemness and differentiation, and alterations in its activity have been associated with tumour development. Recent data highlight the role of Wnt/β-catenin signalling in hepatic metabolism, steatosis and cancer, and suggest targeting of this pathway as a promising molecular strategy to potentially inhibit CLD progression and hepatocarcinogenesis

    Wnt/B-Catenin signalling during liver metabolism, chronic liver disease and hepatocarcinogenesis

    Get PDF
    Chronic liver diseases (CLDs) are increasing in prevalence and their end-stage complications, namely, cirrhosis, liver failure and hepatocellular carcinoma represent major global challenges. The most common initiators of progressive CLD are viral hepatitis and long-term alcohol abuse as well as steatosis and steatohepatitis. Irrespective of the underlying aetiology, a common feature of CLD is the formation of hepatic ductular reactions, involving the proliferation of liver progenitor cells (LPCs) and their sig­nalling to fibrosis-driving hepatic stellate cells. The Wnt/β-catenin pathway has been found to regulate development, stemness and differentiation, and alterations in its activity have been associated with tumour development. Recent data highlight the role of Wnt/β-catenin signalling in hepatic metabolism, steatosis and cancer, and suggest targeting of this pathway as a promising molecular strategy to potentially inhibit CLD progression and hepatocarcinogenesis

    TWEAK/Fn14 signalling regulates the tissue microenvironment in chronic pancreatitis

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    Chronic pancreatitis increases the risk of developing pancreatic cancer through the upregulation of pathways favouring proliferation, fibrosis, and sustained inflammation. We established in previous studies that the ligand tumour necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) signals through its cognate receptor fibroblast growth factor-inducible 14 (Fn14) to regulate these underlying cellular processes in the chronic liver injury niche. However, the role of the TWEAK/Fn14 signalling pathway in pancreatic disease is entirely unknown. An analysis of publicly available datasets demonstrated that the TWEAK receptor Fn14 is upregulated in pancreatitis and pancreatic adenocarcinoma, with single cell RNA sequencing revealing pancreatic ductal cells as the main Fn14 producers. We then used choline-deficient, ethionine-supplemented (CDE) diet feeding of wildtype C57BL/6J and Fn14 knockout littermates to (a) confirm CDE treatment as a suitable model of chronic pancreatitis and (b) to investigate the role of the TWEAK/Fn14 signalling pathway in pancreatic ductal proliferation, as well as fibrotic and inflammatory cell dynamics. Our time course data obtained at three days, three months, and six months of CDE treatment reveal that a lack of TWEAK/Fn14 signalling significantly inhibits the establishment and progression of the tissue microenvironment in CDE-induced chronic pancreatitis, thus proposing the TWEAK/Fn14 pathway as a novel therapeutic target

    TWEAK/Fn14 signalling promotes cholangiocarcinoma niche formation and progression.

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    Background & Aims: Cholangiocarcinoma (CCA) is a cancer of the hepatic bile ducts that is rarely resectable and is associated with poor prognosis. Tumour necrosis factor-like weak inducer of apoptosis (TWEAK) is known to signal via its receptor fibroblast growth factor-inducible 14 (Fn14) and induce cholangiocyte and myofibroblast proliferation in liver injury. We aimed to characterise its role in CCA. Methods: The expression of the TWEAK ligand and Fn14 receptor was assessed immunohistochemically and by bulk RNA and single cell transcriptomics of human liver tissue. Spatiotemporal dynamics of pathway regulation were comprehensively analysed in rat and mouse models of thioacetamide (TAA)-mediated CCA. Flow cytometry, qPCR and proteomic analyses of CCA cell lines and conditioned medium experiments with primary macrophages were performed to evaluate the downstream functions of TWEAK/Fn14. In vivo pathway manipulation was assessed via TWEAK overexpression in NICD/AKT-induced CCA or genetic Fn14 knockout during TAA-mediated carcinogenesis. Results: Our data reveal TWEAK and Fn14 overexpression in multiple human CCA cohorts, and Fn14 upregulation in early TAA-induced carcinogenesis. TWEAK regulated the secretion of factors from CC-SW-1 and SNU-1079 CCA cells, inducing polarisation of proinflammatory CD206+ macrophages. Pharmacological blocking of the TWEAK downstream target chemokine monocyte chemoattractant protein 1 (MCP-1 or CCL2) significantly reduced CCA xenograft growth, while TWEAK overexpression drove cancer-associated fibroblast proliferation and collagen deposition in the tumour niche. Genetic Fn14 ablation significantly reduced inflammatory, fibrogenic and ductular responses during carcinogenic TAA-mediated injury. Conclusion: These novel data provide evidence for the action of TWEAK/Fn14 on macrophage recruitment and phenotype, and cancer-associated fibroblast proliferation in CCA. Targeting TWEAK/Fn14 and its downstream signals may provide a means to inhibit CCA niche development and tumour growth. Lay summary: Cholangiocarcinoma is an aggressive, chemotherapy-resistant liver cancer. Interactions between tumour cells and cells that form a supportive environment for the tumour to grow are a source of this aggressiveness and resistance to chemotherapy. Herein, we describe interactions between tumour cells and their supportive environment via a chemical messenger, TWEAK and its receptor Fn14. TWEAK/Fn14 alters the recruitment and type of immune cells in tumours, increases the growth of cancer-associated fibroblasts in the tumour environment, and is a potential target to reduce tumour formation

    Comparative studies of the immunogenicity and protective potential of biofilm vs planktonic Staphylococcus aureus vaccine against bovine mastitis using non-invasive mouse mastitis as a model system

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    This study was undertaken to compare the immunogenicity and protective potential of biofilm vs planktonic Staphylococcus aureus vaccine for the prevention of mastitis using the mouse as a model system. Mice immunized with formalin-killed whole cell vaccine of S. aureus residing in a biofilm when delivered via an intramammary route produced a cell mediated immune response. Mice immunized with this biofilm vaccine showed significant reductions in colonization by S. aureus in mammary glands, severity of clinical symptoms and tissue damage in mammary glands in comparison with the mice immunized with formalin-killed whole cells of planktonic S. aureus. The planktonic vaccine administered by a subcutaneous route produced a significantly higher humoral immune response (IgG1 and IgG) than the biofilm vaccine. However, considering the host response, tissue damage, the clinical severity and colonization of S. aureus in mammary glands, the biofilm vaccine performed better in immunogenicity and protective potential when administered by the intramammary route

    Wnt/ß-Catenin Signalling during Liver Metabolism, Chronic Liver Disease and Hepatocarcinogenesis

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    Chronic liver diseases (CLDs) are increasing in prevalence and their end-stage complications, namely, cirrhosis, liver failure and hepatocellular carcinoma represent major global challenges. The most common initiators of progressive CLD are viral hepatitis and long-term alcohol abuse as well as steatosis and steatohepatitis. Irrespective of the underlying aetiology, a common feature of CLD is the formation of hepatic ductular reactions, involving the proliferation of liver progenitor cells (LPCs) and their signalling to fibrosis-driving hepatic stellate cells. The Wnt/β-catenin pathway has been found to regulate development, stemness and differentiation, and alterations in its activity have been associated with tumour development. Recent data highlight the role of Wnt/β-catenin signalling in hepatic metabolism, steatosis and cancer, and suggest targeting of this pathway as a promising molecular strategy to potentially inhibit CLD progression and hepatocarcinogenesis

    A Comparative Study of Enumeration Techniques for Free-Roaming Dogs in Rural Baramati, District Pune, India

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    The presence of unvaccinated free-roaming dogs (FRD) amidst human settlements is a major contributor to the high incidence of rabies in countries such as India, where the disease is endemic. Estimating FRD population size is crucial to the planning and evaluation of interventions, such as mass immunisation against rabies. Enumeration techniques for FRD are resource intensive and can vary from simple direct counts to statistically complex capture-recapture techniques primarily developed for ecological studies. In this study we compared eight capture-recapture enumeration methods (Lincoln–Petersen’s index, Chapman’s correction estimate, Beck’s method, Schumacher-Eschmeyer method, Regression method, Mark-resight logit normal method, Huggin’s closed capture models and Application SuperDuplicates on-line tool) using direct count data collected from Shirsuphal village of Baramati town in Western India, to recommend a method which yields a reasonably accurate count to use for effective vaccination coverage against rabies with minimal resource inputs. A total of 263 unique dogs were sighted at least once over 6 observation occasions with no new dogs sighted on the 7th occasion. Besides this direct count, the methods that do not account for individual heterogeneity yielded population estimates in the range of 248–270, which likely underestimate the real FRD population size. Higher estimates were obtained using the Huggin’s Mh-Jackknife (437 ± 33), Huggin’s Mth-Chao (391 ± 26), Huggin’s Mh-Chao (385 ± 30), models and Application “SuperDuplicates” tool (392 ± 20) and were considered more robust. When the sampling effort was reduced to only two surveys, the Application SuperDuplicates online tool gave the closest estimate of 349 ± 36, which is 74% of the estimated highest population of free-roaming dogs in Shirsuphal village. This method may thus be considered the most reliable method for estimating the FRD population with minimal inputs (two surveys conducted on consecutive days)
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