Mus musculus
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA264053 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Acetylation of transcriptional regulators is normally dynamically regulated by nutrient status but is often persistently elevated in nutrient-excessive obesity conditions. We investigated the functional consequences of such aberrantly elevated acetylation of the nuclear receptor FXR as a model. Proteomic studies identified K217 as the FXR acetylation site in diet-induced obese mice. In vivo studies utilizing acetylation-mimic and -defective K217 mutants and gene expression profiling revealed that FXR acetylation increased proinflammatory gene expression, macrophage infiltration, and liver cytokine and triglyceride levels, impaired insulin signaling, and increased glucose intolerance. Mechanistically, acetylation of FXR blocked its interaction with the SUMO ligase PIASy and inhibited SUMO2 modification at K277, resulting in activation of inflammatory genes. SUMOylation of agonist-activated FXR increased its interaction with NF-κB but blocked that with RXRα, so that SUMO2-modified FXR was selectively recruited to and trans-repressed inflammatory genes without affecting FXR/RXRα target genes. A dysregulated Acetyl/SUMO switch of FXR in obesity may serve as a general mechanism for diminished anti-inflammatory response of other transcriptional regulators and provide potential therapeutic and diagnostic targets for obesity-related metabolic disorders. FXR-WT or the FXR-K217Q mutant was expressed in lean mice and FXR-WT or the FXR-K217R mutant was expressed in obese mice by adenoviral infection. One week after infection, mice were treated with GW4064 (30 mg/kg in corn oil) overnight before sacrifice and hepatic expression was analyzed by Illumina microarray.
2014-10-17 | E-GEOD-62414 | biostudies-arrayexpress
Project description:Acetylation of transcriptional regulators is normally dynamically regulated by nutrient status but is often persistently elevated in nutrient-excessive obesity conditions. We investigated the functional consequences of such aberrantly elevated acetylation of the nuclear receptor FXR as a model. Proteomic studies identified K217 as the FXR acetylation site in diet-induced obese mice. In vivo studies utilizing acetylation-mimic and -defective K217 mutants and gene expression profiling revealed that FXR acetylation increased proinflammatory gene expression, macrophage infiltration, and liver cytokine and triglyceride levels, impaired insulin signaling, and increased glucose intolerance. Mechanistically, acetylation of FXR blocked its interaction with the SUMO ligase PIASy and inhibited SUMO2 modification at K277, resulting in activation of inflammatory genes. SUMOylation of agonist-activated FXR increased its interaction with NF-κB but blocked that with RXRα, so that SUMO2-modified FXR was selectively recruited to and trans-repressed inflammatory genes without affecting FXR/RXRα target genes. A dysregulated Acetyl/SUMO switch of FXR in obesity may serve as a general mechanism for diminished anti-inflammatory response of other transcriptional regulators and provide potential therapeutic and diagnostic targets for obesity-related metabolic disorders.
2014-10-17 | GSE62414 | GEO
Project description:Roux-en-Y gastric bypass (RYGB) is highly effective in reversing obesity and associated diabetes. Recent observations in humans suggest a contributing role of increased circulating bile acids in mediating such effects. Here we use a diet-induced obesity mouse model and compared metabolic remission when bile flow was diverted through a gallbladder anastomosis to jejunum, ileum or duodenum (sham control). We found that only bile diversion to the ileum results in physiologic changes similar to RYGB including sustained improvements in weight, glucose tolerance and hepatic steatosis despite differential effects on hepatic gene expression. Circulating free fatty acids and triglycerides decrease while bile acids increase, particularly conjugated tauro-b-muricholic acid, an FXR antagonist. Activity of the hepatic FXR/FGF15 axis was reduced and associated with altered gut microbiota. Thus bile diversion, independent of surgical rearrangement of the gastrointestinal tract, imparts significant weight loss accompanied by improved glucose and lipid homeostasis that are hallmarks of RYGB. Total RNA from n = 5 DIO, n = 4 GB-IL, n = 5 RYGB mice livers was extracted of total RNA and submitted fro RNAseq
2015-05-13 | E-GEOD-68812 | biostudies-arrayexpress
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:Roux-en-Y gastric bypass (RYGB) is highly effective in reversing obesity and associated diabetes. Recent observations in humans suggest a contributing role of increased circulating bile acids in mediating such effects. Here we use a diet-induced obesity mouse model and compared metabolic remission when bile flow was diverted through a gallbladder anastomosis to jejunum, ileum or duodenum (sham control). We found that only bile diversion to the ileum results in physiologic changes similar to RYGB including sustained improvements in weight, glucose tolerance and hepatic steatosis despite differential effects on hepatic gene expression. Circulating free fatty acids and triglycerides decrease while bile acids increase, particularly conjugated tauro-b-muricholic acid, an FXR antagonist. Activity of the hepatic FXR/FGF15 axis was reduced and associated with altered gut microbiota. Thus bile diversion, independent of surgical rearrangement of the gastrointestinal tract, imparts significant weight loss accompanied by improved glucose and lipid homeostasis that are hallmarks of RYGB.
2015-05-13 | GSE68812 | GEO
Project description:Farnesoid X receptor (FXR) plays a prominent role in hepatic lipid metabolism. The FXR gene encodes four proteins with structural differences suggestive of discrete biological functions about which little is known. We show that FXR isoforms have specific effects on hepatic metabolism and uncover novel pathways under their control. Gene expression profiling of hepatocytes expressing each FXR variant revealed large differences in their target gene sets. Notably, FXRα2 (but not α1) activates a broad transcriptional program in hepatocytes conducive to lipolysis, fatty acid oxidation, and ketogenesis. Consequently, FXRα2 decreases cellular lipid accumulation and improves insulin sensitivity. FXRα2 expression in Fxr-/- mouse liver activates a similar gene program and robustly decreases hepatic triglyceride levels. On the other hand, FXRα1 reduces hepatic triglyceride content to a lesser extent and does so through regulation of lipogenic gene expression. Bioenergetic cues, such as fasting and exercise, dynamically regulate Fxr splicing in mouse liver to increase Fxrα2 expression. Our results show that the main FXR variants in human liver (α1 and α2) reduce hepatic lipid accumulation through distinct mechanisms and to different degrees. Thus, pharmacological or lifestyle interventions, such as exercise, aimed at modulating hepatic FXR splicing may improve the therapeutic efficacy of FXR agonists.
2015-09-28 | GSE73035 | GEO
Project description:Accumulation of excess nutrients hampers proper liver function and is linked to non-alcoholic fatty liver disease (NAFLD) in obesity. However, the signals responsible for an impaired adaptation of hepatocytes to obesogenic dietary cues remain still largely unknown. Post-translational modification by the Small Ubiquitin-like Modifier (SUMO), allows for adynamic regulation of numerous processes including transcriptional reprograming. We demonstrate that specific SUMOylation of transcription factor Prox1 represents a nutrient-sensitive determinant of hepatic fasting metabolism. Prox1 was highly SUMOylated on lysine 556 in the liver of ad libitum and re-fed mice, while this modification was abolished upon fasting. In the context of diet-induced obesity, Prox1 SUMOylation became less sensitive to fasting cues. The hepatocyte-selective knock-in of a SUMOylation-deficient Prox1 mutant into mice fed a high-fat/high-fructose diet led to a reduction of systemic cholesterol levels, associated with the induction of liver bile acid detoxifying pathways during fasting. The generation of tools to maintain the nutrient-sensitive SUMO-switch on Prox1 may thus contribute to the development of “fasting-based” approaches for the preservation of metabolic health.
2023-10-24 | PXD041329 | Pride
Project description:Accumulation of excess nutrients hampers proper liver function and is linked to non-alcoholic fatty liver disease (NAFLD) in obesity. However, the signals responsible for an impaired adaptation of hepatocytes to obesogenic dietary cues remain still largely unknown. Post-translational modification by the Small Ubiquitin-like Modifier (SUMO), allows for a dynamic regulation of numerous processes including transcriptional reprograming. We demonstrate that specific SUMOylation of transcription factor Prox1 represents a nutrient-sensitive determinant of hepatic fasting metabolism. Prox1 is highly SUMOylated on lysine 556 in the liver of ad libitum and re-fed mice, while this modification is abolished upon fasting. In the context of diet-induced obesity, Prox1 SUMOylation becomes less sensitive to fasting cues. The hepatocyte-selective knock-in of a SUMOylation-deficient Prox1 mutant into mice fed a high-fat/high-fructose diet leads to a reduction of systemic cholesterol levels, associated with the induction of liver bile acid detoxifying pathways during fasting. The generation of tools to maintain the nutrient-sensitive SUMO-switch on Prox1 may thus contribute to the development of “fasting-based” approaches for the preservation of metabolic health.
2023-07-24 | GSE237593 | GEO
Project description:Accumulation of excess nutrients hampers proper liver function and is linked to non-alcoholic fatty liver disease (NAFLD) in obesity. However, the signals responsible for an impaired adaptation of hepatocytes to obesogenic dietary cues remain still largely unknown. Post-translational modification by the Small Ubiquitin-like Modifier (SUMO), allows for a dynamic regulation of numerous processes including transcriptional reprograming. We demonstrate that specific SUMOylation of transcription factor Prox1 represents a nutrient-sensitive determinant of hepatic fasting metabolism. Prox1 is highly SUMOylated on lysine 556 in the liver of ad libitum and re-fed mice, while this modification is abolished upon fasting. In the context of diet-induced obesity, Prox1 SUMOylation becomes less sensitive to fasting cues. The hepatocyte-selective knock-in of a SUMOylation-deficient Prox1 mutant into mice fed a high-fat/high-fructose diet leads to a reduction of systemic cholesterol levels, associated with the induction of liver bile acid detoxifying pathways during fasting. The generation of tools to maintain the nutrient-sensitive SUMO-switch on Prox1 may thus contribute to the development of “fasting-based” approaches for the preservation of metabolic health.
2023-07-24 | GSE237590 | GEO
Project description:Aging and unhealthy diets are risks for metabolic diseases including liver cancer. Bile acid receptor farnesoid X receptor (FXR) knockout (KO) mice develop metabolic liver diseases and progress into liver cancer as they age, and Western diet (WD) intake facilitates liver carcinogenesis in those mice. This study aimed to uncover molecular signatures within the gut-liver axis for diet and age-linked liver diseases in FXR-dependent or independent manners. Many more transcripts were changed due to WD intake and aging in WT mice than those in FXR KO mice. In other words, WD intake and aging impact the hepatic transcriptomes and metabolomes in an FXR-dependent manner. In WT mice, WD/aging upregulated inflammation-related genes and downregulated genes involved in oxidative phosphorylation (OXPHOS). Urine metabolomes provided clear distinguishing for differential dietary intake. By contrast, the metabolomes of the liver, serum, or urine could reflect age differences. Further, irrespective of differential diets intake or ages, transcriptomes, metabolomes, and cecal microbiota distinguished WT and FXR KO. Western dietary patterns and aging share molecular commonality with FXR deactivation. Notably, WD, aging, and FXR deactivation commonly altered hepatic cell division-related transcripts (Cenpe, Ect2, Top2a, Kif20a, Tpx2, Nuf2, Kif18b, Aspm, E2f8, and Hmmr), which are associated with overall survival rate in HCC patients. In conclusion, FXR is essential for maintaining metabolic homeostasis in response to WD intake and aging. FXR activation helps to alleviate diet and/or aging-induced metabolic health issues.
2023-02-22 | GSE216375 | GEO