MicroRNA-185 modulates CYP7A1 mediated bile acid metabolism through posttranscriptionally and posttranslationally regulation of FoxO1
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE169693 | GEO | 2023/03/26
REPOSITORIES: GEO
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Project description:Bile acids are not only physiological detergents facilitating nutrient absorption, but also signaling molecules regulating metabolic homeostasis. We reported recently that transgenic expression of CYP7A1 in mice stimulated bile acid synthesis and prevented Western diet-induced obesity, insulin resistance and hepatic steatosis. The aim of this experiment is to determine the impact of induction of hepatic bile acid synthesis on liver metabolism by determining hepatic gene expression profile in CYP7A1 transgenic mice. CYP7A1 transgenic mice and wild type control mice were fed either standard chow diet or high fat high cholesterol Western diet for 4 month. Hepatic gene expressions were measured by microarray analysis. Our results indicate that hepatic bile acid synthesis is closely linked to cholesterogenesis and lipogenesis, and maintaining bile acid homeostasis is improtant in hepatic metabolic homeostasis. Male aged matched (~ 12-14 weeks) CYP7A1 transgenic mice and their wild type control littermates were fed a standard chow diet or a high fat (42%) high cholesterol (0.2%) diet (Harlan Teklad #88137) for 4 month Four groups (4 mice/group) are included in the experiments: Group 1: WT _ Chow Group 2: CYP7A1-tg + chow Group 3: WT + Western diet Group 4: CYP7A1-tg _ Western diet Total liver mRNA was isolated with a RNeasy kit (Qiagen) and used for microarray analysis.
2013-08-15 | E-GEOD-38872 | biostudies-arrayexpress
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:Our work demonstrated that 25-hydroxycholesterol induces the expression of miR-185, a microRNA which reinforces the oxysterol's antiviral effects on hepatic metabolism. We used microarrays to detail the effect of miR-185 on hepatic gene expression, and, within repressed genes, identified an enrichment for genes associated with cholesterol biosynthesis.
2015-10-19 | GSE73165 | GEO
Project description:Bile acids are not only physiological detergents facilitating nutrient absorption, but also signaling molecules regulating metabolic homeostasis. We reported recently that transgenic expression of CYP7A1 in mice stimulated bile acid synthesis and prevented Western diet-induced obesity, insulin resistance and hepatic steatosis. The aim of this experiment is to determine the impact of induction of hepatic bile acid synthesis on liver metabolism by determining hepatic gene expression profile in CYP7A1 transgenic mice. CYP7A1 transgenic mice and wild type control mice were fed either standard chow diet or high fat high cholesterol Western diet for 4 month. Hepatic gene expressions were measured by microarray analysis. Our results indicate that hepatic bile acid synthesis is closely linked to cholesterogenesis and lipogenesis, and maintaining bile acid homeostasis is improtant in hepatic metabolic homeostasis.
2013-08-15 | GSE38872 | GEO
Project description:Ascorbic acid (AA) is a powerful antioxidant and play as a cofactor for various enzymes in vivo. In this study, we investigated the effect of AA depletion on gene expression in the liver and lipid metabolism by using SMP30/GNL knockout (KO) mice which are unable to biosynthesis AA. First, we performed microarray analysis. Briefly, SMP30/GNL KO mice were weaned and divided into two groups; AA-depleted and supplemented groups, which mice were free access to water containing 1.5 g/L AA. After 4 weeks, mRNA was isolated and purified from the liver. In this study, Affymetrix® GeneChip® was used for microarray analysis. Actually, AA-depletion altered many gene expressions related to lipid metabolism. Especially, Cytochrome P450 7a1 (Cyp7a1), a late-limiting enzyme of bile acid biosynthesis, gene expression was significantly up-regulated. We also confirmed Cyp7a1 protein levels by Western blotting. Next, we investigated the influence of AA depletion on lipid metabolism. We examined the lipid and bile acid levels in the liver, plasma, and gallbladder from SMP30/GNL KO mice. Amount of total bile acid (TBA), free fatty acid (FA), total cholesterol (TC), triglyceride (TG), and phospholipids (PL) were measured by colorimetric method. AA depletion reduced TBA levels in the liver and gallbladder. However, FA, TC, TG, and PL in the plasma and liver were not changed by AA depletion. Although Cyp7a1 gene expression and protein levels were increased by AA depletion, amount of bile acid were reduced. Conclusively, we have shown that AA depletion reduced bile acid biosynthesis and elevated Cyp7a1 gene expression and protein levels. Thus, AA is an essential for bile acid biosynthesis pathway.
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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:The disruption of cholesterol homeostasis leads to an increase in cholesterol levels which results in the development of cardiovascular disease. Mitogen Inducible Gene 6 (Mig-6) is an immediate early response gene that can be induced by various mitogens, stresses, and hormones. To identify the metabolic role of Mig-6 in the liver, we conditionally ablated Mig-6 in the liver using the Albumin-Cre mouse model (Albcre/+Mig-6f/f; Mig-6d/d). Mig-6d/d mice exhibit hepatomegaly and fatty liver. Serum levels of total, LDL, and HDL cholesterol and hepatic lipid were significantly increased in the Mig-6d/d mice. The daily excretion of fecal bile acids was significantly decreased in the Mig-6d/d mice. DNA microarray analysis of mRNA isolated from the livers of these mice showed alterations in genes that regulate lipid metabolism, bile acid, and cholesterol synthesis, while the expression of genes that regulate biliary excretion of bile acid and triglyceride synthesis showed no difference in the Mig-6d/d mice compared to Mig-6f/f controls. These results indicate that Mig-6 plays an important role in cholesterol homeostasis and bile acid synthesis. Mice with liver specific conditional ablation of Mig-6 develop hepatomegaly and increased intrahepatic lipid and provide a novel model system to investigate the genetic and molecular events involved in the regulation of cholesterol homeostasis and bile acid synthesis. Defining the molecular mechanisms by which Mig-6 regulates cholesterol homeostasis will provide new insights into the development of more effective ways for the treatment and prevention of cardiovascular disease. Eight week old Mig-6f/f vs Mig-6d/d male mice after undergoing a 24 hour fast
2011-08-30 | E-GEOD-31752 | biostudies-arrayexpress
Project description:The disruption of cholesterol homeostasis leads to an increase in cholesterol levels which results in the development of cardiovascular disease. Mitogen Inducible Gene 6 (Mig-6) is an immediate early response gene that can be induced by various mitogens, stresses, and hormones. To identify the metabolic role of Mig-6 in the liver, we conditionally ablated Mig-6 in the liver using the Albumin-Cre mouse model (Albcre/+Mig-6f/f; Mig-6d/d). Mig-6d/d mice exhibit hepatomegaly and fatty liver. Serum levels of total, LDL, and HDL cholesterol and hepatic lipid were significantly increased in the Mig-6d/d mice. The daily excretion of fecal bile acids was significantly decreased in the Mig-6d/d mice. DNA microarray analysis of mRNA isolated from the livers of these mice showed alterations in genes that regulate lipid metabolism, bile acid, and cholesterol synthesis, while the expression of genes that regulate biliary excretion of bile acid and triglyceride synthesis showed no difference in the Mig-6d/d mice compared to Mig-6f/f controls. These results indicate that Mig-6 plays an important role in cholesterol homeostasis and bile acid synthesis. Mice with liver specific conditional ablation of Mig-6 develop hepatomegaly and increased intrahepatic lipid and provide a novel model system to investigate the genetic and molecular events involved in the regulation of cholesterol homeostasis and bile acid synthesis. Defining the molecular mechanisms by which Mig-6 regulates cholesterol homeostasis will provide new insights into the development of more effective ways for the treatment and prevention of cardiovascular disease.
2011-08-31 | GSE31752 | GEO
Project description:An improved mechanistic understanding of the thyroid hormone (TH) action on bile acid (BA) synthetic pathway, the major route for cholesterol elimination, will facilitate the identification of novel therapeutic targets for hypercholesterolemia. Here, we show that hepatic miR-378 is positively regulated by TH. Transient overexpression of miR-378 in the liver of mice reduces the serum cholesterol levels, which is accompanied with an upregulation of key enzymes involved in the intrahepatic conversion of cholesterol to BAs. Importantly, transgenic mice with liver-specific and moderate overexpression of miR-378 also display a decrease in serum cholesterol levels accompanied with an enhanced BA synthesis and are resistant to diet-induced hypercholesterolemia. In contrast, mice lacking miR-378 exhibit an elevation of serum cholesterol levels accompanied with an impaired BA synthesis. Mechanistic studies reveal that hepatic miR-378 regulates BA synthesis and cholesterol homeostasis through its direct target gene MAFG, which is a transcriptional repressor of BA synthetic genes. We also show that miR-378 serves as an essential component in either incoherent or coherent feed-forward loop to confer robust and precise controls on BA synthesis in response to TH signalling. Together, we identify a previously undescribed miR-378-mediated mechanism underlying the cholesterol-lowering effect of TH. Our findings not only add a new dimension to our understanding the regulation of BA synthesis by TH, but also provide new therapeutic regimens to manage serum cholesterol levels
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Project description:T cell-specific overexpression of miR-185 caused a developmental block at DN3 stage of thymopoiesis. DN3 stage thymocytes were sorted from the wild type (C57BL/6) and miR-185 Tg mice, followed by total RNA isolation.
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