Project description:The farnesoid X receptor (FXR) is a nuclear receptor activated by bile acids and regulates bile acid metabolism, glucose and cholesterol homeostasis. From mouse studies we know that the novel FXR agonist obeticholic acid (OCA) regulates expression of many genes in the liver, but there is currently no data on the effects of OCA on human liver gene expression. This is especially relevant since the novel FXR agonist OCA is currently tested in clinical trials for the treatment of several diseases, such as nonalcoholic steatohepatitis (NASH), nonalcoholic fatty liver disease (NAFLD) and Type 2 Diabetes. In this study we investigate the effect of OCA treatment on gene expression profiles and localization of FXR to the genome in relevant liver samples. ChIP-Seq for FXR in Liver tissue from 2 male mice treated with OCA/INT-747 (10mg/kg/day) and 2 male mice treated with vehicle (1% methyl cellulose).
Project description:The farnesoid X receptor (FXR) is a nuclear receptor activated by bile acids and regulates bile acid metabolism, glucose and cholesterol homeostasis. From mouse studies we know that the novel FXR agonist obeticholic acid (OCA) regulates expression of many genes in the liver, but there is currently no data on the effects of OCA on human liver gene expression. This is especially relevant since the novel FXR agonist OCA is currently tested in clinical trials for the treatment of several diseases, such as nonalcoholic steatohepatitis (NASH), nonalcoholic fatty liver disease (NAFLD) and Type 2 Diabetes. In this study we investigate the effect of OCA treatment on gene expression profiles and localization of FXR to the genome in relevant liver samples.
Project description:The farnesoid X receptor (FXR) is a nuclear receptor activated by bile acids that regulates metabolic processes. FXR is expressed as four isoforms (α1-4), and their relative abundance is specific to tissue and bio-energetic conditions (Correia JC et al. 2015). Depending on the FXR isoform expressed, there is a degree of selectivity in target-genes activation. In this dataset, we defined FXR-isoforms selective effects on transcription in mouse liver organoids after treatment with the FXR agonist Obeticholic acid(OCA). By linking the DNA binding profiles of the FXR isoforms with their transcriptional output, we concluded that differential DNA binding plays a defining role in FXR-isoform target gene selectivity.
Project description:The farnesoid X receptor (FXR) is a nuclear receptor activated by bile acids that regulates bile acid metabolism, glucose and cholesterol homeostasis. FXR is expressed as four isoforms (α1-4), and their relative abundance is tissue specific. Human livers express predominantly FXR isoforms α1 and α2. From mouse studies we know that the FXR agonist obeticholic acid (OCA) regulates expression of many genes in the liver. However, there is currently no data on the effects of OCA on FXR isoform selective gene regulation. This is particularly relevant since the relative FXR isoform amounts in the liver are regulated by general bioenergetic cues (Correia JC et al. 2015). In this study we investigate the effect of variations in FXR isoforms α1 or α2 expression on HepG2 cell lines response to treatment with OCA.
Project description:Farnesoid X receptor (FXR) agonism is emerging as an important potential therapeutic mechanism of action for multiple chronic liver diseases. The bile acid–derived FXR agonist obeticholic acid (OCA; 6-ethyl chenodeoxycholic acid) has shown promise in a phase 2 study in patients with nonalcoholic steatohepatitis (NASH). Here, we report efficacy of a novel, non–bile acid FXR agonist tropifexor (LJN452) in two distinct preclinical models of NASH. The efficacy of tropifexor at <1 mg/kg doses was superior to that of OCA at 25 mg/kg in the liver in both NASH models. In a chemical and dietary model of NASH (STAM model), tropifexor reversed established fibrosis and reduced nonalcoholic fatty liver disease activity score and hepatic triglycerides. In an insulin-resistant, obese NASH model (AMLN), tropifexor markedly reduced steatohepatitis, fibrosis, and profibrogenic gene expression. Transcriptome analysis of livers from AMLN mice revealed 461 differentially expressed genes following tropifexor treatment, which included a combination of signatures associated with reduction of oxidative stress, fibrogenesis, and inflammation. Conclusion: Based on the preclinical validation in animal models, tropifexor is a promising investigational therapy that is currently under phase 2 development for NASH.
Project description:The farnesoid X receptor (FXR) is a nuclear receptor activated by bile acids that regulates metabolic processes. FXR is expressed as four isoforms (α1-4), and their relative abundance is specific to tissue and bio-energetic conditions (Correia JC et al. 2015). Depending on the FXR isoform expressed, there is a degree of selectivity in target-genes activation. However, there is currently no data on how isoform-linked target selectivity is achieved. In this study we investigate the DNA binding profile of FXR isoforms on mouse liver organoids treated briefly with the FXR agonist obeticholic acid (OCA). From this analysis we concluded that FXR isoforms α2 and α4 binds to additional DNA regions, enriched for a specific discriminating binding motif. This binding led to isoform-selective gene regulation. Therefore, DNA binding selectivity therefore plays a defining role in FXR isoform-specific effects.
Project description:Background: The bile acid-activated farnesoid X receptor (FXR) is a nuclear receptor regulating bile acid, glucose and cholesterol homeostasis. Obeticholic acid (OCA; also known as INT-747 or 6α-ethyl-chenodeoxycholic acid), a promising drug for the treatment of non-alcoholic steatohepatitis (NASH) and type 2 diabetes, activates FXR. Mouse studies demonstrated that FXR activation by OCA (INT-747) alters hepatic expression of many genes. However, no data are available on the effects of OCA in human liver. Here, we generated gene expression profiles in human precision-cut liver slices (hPCLS) after treatment with OCA. Methods: hPCLS were incubated with OCA for 24 h. WT or FXR -/- mice received OCA or vehicle by oral gavage for 7 days. Results: Transcriptomic analysis showed that well-known FXR target genes, including NR0B2 (SHP), ABCB11 (BSEP), SLC51A (OSTα) and SLC51B (OSTβ) and ABCB4 (MDR3), are regulated by OCA in hPCLS. Ingenuity pathway analysis confirmed that 'FXR/RXR activation' is the most significantly changed pathway upon OCA treatment. Comparison of gene expression profiles in hPCLS and mouse livers identified 18 common potential FXR targets. ChIP-sequencing in mouse liver confirmed FXR binding to IR1 sequences of Akap13, Cgnl1, Dyrk3, Pdia5, PPP1R3B and Tbx6. Conclusions: Our study shows that hPCLS respond to OCA treatment by upregulating well-known FXR target genes, demonstrating its suitability to study FXR-mediated gene regulation. We identified 6 novel bona-fide FXR target genes in both mouse and human liver. Finally, we discuss a possible explanation for changes in HDL/LDL observed in NASH and primary biliary cirrhosis patients treated with OCA based on the genomic expression profile in hPCLS.