Project description:BCAA were administered to atherogenic and high-fat (Ath & HF) diet-induced nonalcoholic steatohepatitis (NASH) model mice and platelet-derived growth factor C transgenic mice (Pdgf-c Tg). Liver histology, tumor incidence, and gene expression profiles were evaluated. BCAA supplementation improved hepatic steatosis, inflammation, fibrosis, and tumors in the NASH mouse model, possibly through the modification of mTORC1 signaling.
Project description:Whole Exome Sequencing of cohorts of Mutant Braf mouse model melanoma DNA and germline DNA. The cohorts are (1) Mutant Braf mouse model melanomas, (2) Mutant Braf mouse model melanomas from UVR exposed mice and (3) Mutant Braf mouse model melanomas from UVR exposed, sunscreen protected mice.
Project description:Metabolic dysfunction-associated steatotic liver disease (MASLD) is a widespread chronic liver disorder spanning simple steatosis to metabolic dysfunction-associated steatohepatitis (MASH) and fibrosis. Suitable animal models are crucial for therapeutic development, yet many fail to reproduce progression to fibrosing MASH. Here, we employed the STAM model in male C57BL/6J mice to simulate MASLD and investigated whether a high-fat, high-cholesterol (HFHC) diet would intensify disease progression compared with the standard high-fat (HF) diet. HFHC feeding in the STAM model accelerated hepatic lipid accumulation, crown-like structure formation, inflammation, and fibrosis, as demonstrated by histological analyses. Transcriptomic profiling and pathway enrichment confirmed activation of lipid and cholesterol metabolism, regulation of TNF production, and inflammatory signaling. Reactome analysis further indicated alterations in extracellular matrix formation and immune system pathways, consistent with advanced fibrotic progression. In summary, integration of HFHC feeding with the STAM model produced a more severe liver phenotype that better mirrors the pathological spectrum of MASLD.
Project description:Liver zonation characterizes the separation of metabolic pathways along the lobules and is required for optimal hepatic function. Wnt signaling is a master regulator of spatial liver zonation. A perivenous-periportal Wnt activity gradient orchestrates metabolic zonation by activating genes in perivenous hepatocytes, while suppressing genes in their periportal counterparts. The understanding of liver gene zonation and zonation regulators in disease was limited. Non-alcoholic steatohepatitis (NASH) is a chronic liver disease characterized by fat accumulation, inflammation, and fibrosis. Here, we investigated the perturbation of liver gene zonation in a mouse NASH model by combination of spatial transcriptomics, bulk RNAseq and in situ hybridization. Wnt target genes represented a major subset of genes showing altered spatial expression in the NASH liver. The altered Wnt target gene expression level and zonation spatial pattern were in line with the upregulation of Wnt regulators and the augmentation of Wnt signaling. Particularly, we found that the Wnt activator Rspo3 expression was restricted to the perivenous zone in control livers, whereas expanded to the periportal zone in NASH livers. AAV8-mediated RSPO3 overexpression in controls resulted in a zonation change, and further amplified the disturbed zonation of Wnt target genes in NASH, but had no impacts on steatosis, inflammation and fibrosis. In summary, our study demonstrated the alteration of Wnt signaling in a mouse NASH model, leading to perturbed liver zonation.
Project description:Through mass spectrometry, we quantified liver global proteomes of Simple steatosis and Non-alcoholic Steatohepatitis in a HFHC diet induced mouse model
Project description:The mechanisms underlying the progression of non-alcoholic steatohepatitis (NASH) are not completely elucidated. In this study we have integrated gene expression profiling of liver biopsies of NASH patients with translational studies in a mouse model of steatohepatitis and with pharmacological interventions in isolated hepatocytes to identify a novel mechanism implicated in the pathogenesis of NASH. By using high-density oligonucleotide microarray analysis we identified a significant enrichment of known genes involved in the multi-step catalysis of long chain polyunsaturated fatty acids, including delta-5 and 6 desaturases. A combined inhibitor of delta-5 and delta-6 desaturases significantly reduced intracellular lipid accumulation and inflammatory gene expression in isolated hepatocytes. Gas chromatography analysis revealed impaired delta-5 desaturase activity toward the omega-3 pathway in livers from mice with high-fat diet (HFD)-induced NASH. Consistently, restoration of omega-3 index in transgenic fat-1 mice expressing an omega-3 desaturase, which allows the endogenous conversion of omega-6 into omega-3 fatty acids, produced a significant reduction in hepatic insulin resistance, hepatic steatosis, macrophage infiltration and necroinflammatory liver injury, accompanied by attenuated expression of genes involved in inflammation, fatty acid uptake and lipogenesis. These results were comparable to those obtained in a group of mice receiving a HFD supplemented with EPA/DHA. Of interest, hepatocytes from fat-1 mice or supplemented with EPA exhibited synergistic anti-steatotic and anti-inflammatory actions with the delta-5/ delta-6 inhibitor. Conclusion: These findings indicate that both endogenous and exogenous restoration of the hepatic balance between omega-6 and omega-3 fatty acids and/or modulation of desaturase activities exert preventive actions in NASH. The complete database comprised the expression measurements of 18185 genes for liver sample groups: 8 non-alcoholic steatohepatitis (NASH ) and 7 control samples. This dataset is part of the TransQST collection.