Mus musculus
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA225470 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:The nuclear receptor FXR acts as an intracellular bile salt sensor that regulates synthesis and transport of bile salts within their enterohepatic circulation. In addition, FXR is involved in control of a variety of crucial metabolic pathways. Four FXR splice variants are known, i.e. FXRα1-4. Although these isoforms show differences in spatial and temporal expression patterns as well as in transcriptional activity, the physiological relevance hereof has remained elusive. We have evaluated specific roles of hepatic FXRα2 and FXRα4 by stably expressing these isoforms using liver-specific self-complementary adeno-associated viral vectors in total body FXR knock-out mice. The hepatic gene expression profile of the FXR knock-out mice was largely normalized by both isoforms. Yet, differential effects were also apparent; FXRα2 was more effective in reducing elevated HDL levels and transrepressed hepatic expression of Cyp8B1, the regulator of cholate synthesis. The latter coincided with a switch in hydrophobicity of the bile salt pool. Furthermore, FXRα2-transduction caused an increased neutral sterol excretion compared to FXRα4 without affecting intestinal cholesterol absorption. Our data show, for the first time, that hepatic FXRα2 and FXRα4 differentially modulate bile salt and lipoprotein metabolism in mice.
2014-11-11 | GSE51805 | GEO
Project description:Deoxycholic acid (DCA) is a secondary bile acid produced by a small number of commensal species of bacteria present in the mammalian gut. Elevated DCA concentration correlates with disease states including colon cancer and cholesterol gallstones, but the associated mechanisms are not fully understood. Both primary and secondary bile acids are also capable of affecting gene expression through nuclear receptors such as FXR. To better understand the impact of a commensal-derived secondary bile acid on host metabolism we fed DCA to germ-free (GF) mice, which normally lack DCA, and compared the hepatic transcriptomes of bile acid fed GF mice to GF mice receiving a control diet, as well as to those of conventionally housed control animals. Interestingly, the feeding of DCA to GF mice, but not the feeding of cholic acid (CA) from which DCA is derived, results in an up-regulation of genes of cholesterol biosynthetic pathways. GF mice normally have elevated hepatic cholesterol compared to conventionally housed mice. Despite increase in the expression of cholesterol biosynthetic genes, the DCA fed GF mice showed a markedly decreased level of hepatic cholesterol equivalent to the hepatic cholesterol concentration of conventionally colonized animals. Total cholesterol in the serum was unaffected by DCA, but there was a decrease in the HDL lipoprotein fraction as well as an increase in the non-HDL lipoprotein fraction of the serum cholesterol. DCA, but not CA, is sufficient to modulate host lipoprotein metabolism. Taken together, these results suggests that a minor component of the gut microbiome has a significant impact on cholesterol homeostasis through secondary metabolism of bile acids and suggests a possible therapeutic intervention route through the microbial metabolic pathways. two mouse strains, three diets, one time point
2015-01-08 | E-GEOD-34730 | biostudies-arrayexpress
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.
2020-07-27 | GSE133659 | GEO
Project description:Deoxycholic acid (DCA) is a secondary bile acid produced by a small number of commensal species of bacteria present in the mammalian gut. Elevated DCA concentration correlates with disease states including colon cancer and cholesterol gallstones, but the associated mechanisms are not fully understood. Both primary and secondary bile acids are also capable of affecting gene expression through nuclear receptors such as FXR. To better understand the impact of a commensal-derived secondary bile acid on host metabolism we fed DCA to germ-free (GF) mice, which normally lack DCA, and compared the hepatic transcriptomes of bile acid fed GF mice to GF mice receiving a control diet, as well as to those of conventionally housed control animals. Interestingly, the feeding of DCA to GF mice, but not the feeding of cholic acid (CA) from which DCA is derived, results in an up-regulation of genes of cholesterol biosynthetic pathways. GF mice normally have elevated hepatic cholesterol compared to conventionally housed mice. Despite increase in the expression of cholesterol biosynthetic genes, the DCA fed GF mice showed a markedly decreased level of hepatic cholesterol equivalent to the hepatic cholesterol concentration of conventionally colonized animals. Total cholesterol in the serum was unaffected by DCA, but there was a decrease in the HDL lipoprotein fraction as well as an increase in the non-HDL lipoprotein fraction of the serum cholesterol. DCA, but not CA, is sufficient to modulate host lipoprotein metabolism. Taken together, these results suggests that a minor component of the gut microbiome has a significant impact on cholesterol homeostasis through secondary metabolism of bile acids and suggests a possible therapeutic intervention route through the microbial metabolic pathways.
2015-01-08 | GSE34730 | GEO
Project description:X-box binding protein 1 (XBP1) is a key component of the unfolded protein response that is activated in response to ER stress. Farnesoid X receptor (FXR) null (Fxr-/-) mice have elevated bile acid levels and progressive liver injury. Hepatic XBP1 pathway is activated in older Fxr-/- mice. This project is to investigate the role of liver XBP1 in Fxr-/- mice.
2022-09-19 | GSE201902 | GEO
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.
2020-07-27 | GSE133734 | GEO
Project description:Specific bile acids are potent signaling molecules that modulate metabolic pathways affecting lipid, glucose and bile acid homeostasis, and the microbiota. Bile acids are synthesized from cholesterol in the liver, and the key enzymes involved in bile acid synthesis (Cyp7a1, Cyp8b1) are regulated transcriptionally by the nuclear receptor FXR. We have identified an FXR-regulated pathway upstream of a transcriptional repressor that controls multiple bile acid metabolism genes. We identify MafG as an FXR target gene and show that hepatic MAFG overexpression represses genes of the bile acid synthetic pathway and modifies the biliary bile acid composition. In contrast, loss-of-function studies using MafG(+/-) mice causes de-repression of the same genes with concordant changes in biliary bile acid levels. Finally, we identify functional MafG response elements in bile acid metabolism genes using ChIP-seq analysis. Our studies identify a molecular mechanism for the complex feedback regulation of bile acid synthesis controlled by FXR.
2016-02-04 | GSE77529 | GEO
Project description:Specific bile acids are potent signaling molecules that modulate metabolic pathways affecting lipid, glucose and bile acid homeostasis, and the microbiota. Bile acids are synthesized from cholesterol in the liver, and the key enzymes involved in bile acid synthesis (Cyp7a1, Cyp8b1) are regulated transcriptionally by the nuclear receptor FXR. We have identified an FXR-regulated pathway upstream of a transcriptional repressor that controls multiple bile acid metabolism genes. We identify MafG as an FXR target gene and show that hepatic MAFG overexpression represses genes of the bile acid synthetic pathway and modifies the biliary bile acid composition. In contrast, loss-of-function studies using MafG(+/-) mice causes de-repression of the same genes with concordant changes in biliary bile acid levels. Finally, we identify functional MafG response elements in bile acid metabolism genes using ChIP-seq analysis. Our studies identify a molecular mechanism for the complex feedback regulation of bile acid synthesis controlled by FXR
2016-02-04 | GSE77507 | GEO
Project description:Farnesoid X receptor (FXR) is a ligand activated nuclear receptor belonging to the nuclear receptor superfamily. Bile acids (BAs) are the endogenous ligand for FXR. FXR is a master regulator of BA homestasis, including BA synthesis, metabolism, transport, and enterohepatic circulation of BAs. Besides, FXR is involved in regulating diverse physioligical function in both humans and mice. GW4064 is a synthetic FXR agonist which selectively activates FXR and induce the transcription of FXR target genes.
2014-07-24 | GSE57305 | GEO
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).
2016-01-27 | E-GEOD-73624 | biostudies-arrayexpress