Project description:We find that selective inhibition of one arm of mTORC1 signaling, via deletion of FLCN, promotes activation of the transcription factor TFE3 and profoundly protects against NAFLD and NASH in mice. (1) We performed genome-wide RNA-seq on livers from Control, liver-specific Flcn-null mice (LiFKO), and Flcn/Tfe3 double knock-out (DKO) mice fed either normal chow (NC) or a NAFLD-inducing diet (AMLN). We find TFE3-mediated induction of lysosomal and mitochondrial gene programs, and also suppression of de novo lipogenesis genes. (2) To understand whether TFE3 directly affects gene expression, we performed TFE3 ChIP-seq on livers from Control and LiFKO mice on normal chow. We find TFE3 occupancy on the chromatin at lysosomal genes, Ppargc1a (a driver of mitochondrial genes), and at de novo lipogenesis genes. (3) Finally, we wanted to test whether TFE3 antagonistically competes with the pro-lipogenic transcription factor SREBP-1c on chromatin. We therefore injected HA-tagged constitutively nuclear (active) SREBP-1c (nSREBP-1c), or a control virus, into control and LiFKO mice, treated them with a NAFLD-inducing diet (FPC diet), and collected liver tissue. We consequently performed HA-nSREBP-1c and TFE3 ChIP-seq experiments and observed no evidence of antagonistic competition.
Project description:Non-alcoholic fatty liver disease (NAFLD) is characterized by a series of pathological changes that can progress from simple fatty liver disease to non-alcoholic steatohepatitis (NASH). The objective of this study is to describe changes in global gene expression associated with the progression of NAFLD. This study is focused on the expression levels of genes responsible for the absorption, distribution, metabolism and excretion (ADME) of drugs. Differential gene expression between three clinically defined pathological groups; normal, steatosis and NASH was analyzed. The samples were diagnosed as normal, steatotic, NASH with fatty liver (NASH fatty) and NASH without fatty liver (NASH NF). Genome-wide mRNA levels in samples of human liver tissue were assayed with Affymetrix GeneChipM-. Human 1.0ST arrays
Project description:To characterize gene expression changes in arachidonic acid metabolism pathway genes in the presense of non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH) mice administered were administered an atherogenic diet for a period of four weeks. Administration of the atherogenic diet resulted in significant enrichment of the arachidonic acid metabolism pathway by gene set enrichment analysis (GSEA). The core enrichment subset of genes was down-regulated in mice administered the atherogenic diet and the majority of the genes that were down-regulated were cytochrome P450s. A total of 4 wild-type mice were administered a standard diet (STD; control group) and 4 wild-type mice were administered a HFHC diet (HFHC).
Project description:To understand the role of adipose tissue senescence in NAFLD/NASH, RNA sequencing was performed in the visceral adipose tissue of NAFLD and NASH pateints.
Project description:Non-alcoholic fatty liver disease/steatohepatitis (NAFLD/NASH) is a significant risk factor for hepatocellular carcinoma (HCC). However, a preclinical model of progressive NAFLD/NASH is largely lacking. Here, we report that mice with hepatocyte-specific deletion of Tid1, encoding a mitochondrial cochaperone, tended to develop NASH-dependent HCC. Mice with hepatic Tid1 deficiency showed impairing mitochondrial function and causing fatty acid metabolic dysregulation; meanwhile, sequentially developed fatty liver, NASH, and cirrhosis/HCC in a diethylnitrosamine (DEN) induced oxidative environment. The pathological signatures of human NASH, including cholesterol accumulation and activation of inflammatory and apoptotic signaling pathways, are also present in these mice. Clinically, low Tid1 expression was associated with unfavorable prognosis in patients with HCC. Empirically, hepatic Tid1 deficiency directly disrupts entire mitochondria that play a key role in the NASH-dependent HCC development. Overall, we established a new mouse model that develops NASH-dependent HCC and provides a promising approach to improve the treatment.
Project description:We investigated the hepatic transcriptome of 58 biopsy-proven NAFLD patients at multiple stages of the disease (NAFL, NASH with mild fibrosis, NASH with advanced fibrosis) with the aim of describing the pathophysiological events driving the development and progression of NASH.
Project description:To investigate the mechanism of hepatic Activin A and Gpnmb in NAFLD/NASH, we studied C57BL/6J mice on a FPC NASH diet and sugar water for 16 weeks, compared with standard chow diet, and used adeno-associated viral vectors with a liver-specific thyroxine binding globulin (TBG) promoter to express Activin A or GFP (control), or AAV8-H1-shRNA to knockdown of Gpnmb or scramble control in NAFLD/NASH liver. We then performed gene expression profiling analysis using data obtained from RNA-seq of 3 different livers in each group.
Project description:Dyslipidemia and inflammation play key roles in the pathogenesis of both nonalcoholic fatty liver disease (NAFLD) and atherosclerosis. NAFLD, particularly its severe form nonalcoholic steatohepatitis (NASH) is associated with increased cardiovascular disease (CVD) risk. HDL (high density lipoprotein- also a CVD risk) are decreased in NAFLD but whether HDL function is abnormal in NAFLD is unknown. Furthermore, it is unknown whether dyslipidemia contributes to reduced HDL function in NAFLD and whether hepatic inflammation further impairs HDL function in patients with NASH. Therefore, the aim of this study was to investigate HDL function and to examine the effect of dyslipidemia and inflammation on HDL metabolism in patients with biopsy-proven simple steatosis (SS) and NASH. RESULTS: Compared to controls, SS and NASH subjects had significantly higher levels of plasma triglyceride, insulin, and were more insulin resistant (HOMA, P<0.05) with no differences in total cholesterol, HDL cholesterol, ApoB100 and ApoAI levels. NAFLD patients had increased production and degradation rates of both HDLc and ApoAI that resulted in their levels remaining stable. The degradation rates also were increased of other HDL proteins, including ApoAII, ApoAIV, vitamin D-binding protein, and complement 3 (all P<0.05). NAFLD patients had increased activities of LCAT and CETP, indicating altered HDL lipidation. NAFLD induced alterations in HDL metabolism were associated with reduced anti-oxidant but increased pro-inflammatory activity of HDL. However, no differences were observed in either HDL function or the kinetics of HDLc and HDL proteins between SS and NASH subjects.
Project description:To characterize gene expression changes in arachidonic acid metabolism pathway genes in the presense of non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH) mice administered were administered an atherogenic diet for a period of four weeks. Administration of the atherogenic diet resulted in significant enrichment of the arachidonic acid metabolism pathway by gene set enrichment analysis (GSEA). The core enrichment subset of genes was down-regulated in mice administered the atherogenic diet and the majority of the genes that were down-regulated were cytochrome P450s.
Project description:Non-alcoholic fatty liver disease (NAFLD) encompasses a spectrum of disease that ranges from simple steatosis, to inflammatory form non-alcoholic steatohepatitis (NASH), cirrhosis, and up to hepatocellular carcinoma. While NASH usually takes decades to develop at a rate of one stage per seven years, in the case of post-trasplant NASH (pt-NASH) develops fibrosis much more rapidly, with almost 50% of liver transplant recipients presenting stage 3 fibrosis by 5 years post-transplant. Archived fresh-frozen transplanted liver biopsy samples from four liver biopsy samples with evidence of NASH (2 recurrent and 2 de novo), two with simple steatosis (both de novo), and five with normal histology as controls had their transcriptome sequenced in two batches for deeper coverage.