Mus musculus
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA152837 | ENA |
REPOSITORIES: ENA
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Project description:The liver X receptors (LXRs) are nuclear receptors that form permissive heterodimers with retinoid X receptor (RXR) and are important regulators of lipid metabolism in the liver. We have recently shown that RXR agonist-induced hypertriglyceridemia and hepatic steatosis in mice is dependent on LXR and correlates with an LXR-dependent hepatic induction of lipogenic genes. To further investigate the role of RXR and LXR in the regulation of hepatic gene expression, we have mapped the ligand-regulated genome-wide binding of these factors in mouse liver. We find that the RXR agonist bexarotene primarily increases the genomic binding of RXR, whereas the LXR agonist T0901317 greatly increases both LXR and RXR binding. Functional annotation of putative direct LXR target genes revealed a significant association with classical LXR-regulated pathways as well as PPAR signaling pathways, and subsequent ChIP-seq mapping of PPARα binding demonstrated binding of PPARα to 71-88% of the identified LXR:RXR binding sites. Sequence analysis of shared binding regions combined with sequential ChIP on selected sites indicate that LXR:RXR and PPARα:RXR bind to degenerate response elements in a mutually exclusive manner. Together our findings suggest extensive and unexpected cross-talk between hepatic LXR and PPARα at the level of binding to shared genomic sites
2012-01-31 | GSE35262 | GEO
Project description:The liver X receptors (LXRs) are nuclear receptors that form permissive heterodimers with retinoid X receptor (RXR) and are important regulators of lipid metabolism in the liver. We have recently shown that RXR agonist-induced hypertriglyceridemia and hepatic steatosis in mice is dependent on LXR and correlates with an LXR-dependent hepatic induction of lipogenic genes. To further investigate the role of RXR and LXR in the regulation of hepatic gene expression, we have mapped the ligand-regulated genome-wide binding of these factors in mouse liver. We find that the RXR agonist bexarotene primarily increases the genomic binding of RXR, whereas the LXR agonist T0901317 greatly increases both LXR and RXR binding. Functional annotation of putative direct LXR target genes revealed a significant association with classical LXR-regulated pathways as well as PPAR signaling pathways, and subsequent ChIP-seq mapping of PPARM-NM-1 binding demonstrated binding of PPARM-NM-1 to 71-88% of the identified LXR:RXR binding sites. Sequence analysis of shared binding regions combined with sequential ChIP on selected sites indicate that LXR:RXR and PPARM-NM-1:RXR bind to degenerate response elements in a mutually exclusive manner. Together our findings suggest extensive and unexpected cross-talk between hepatic LXR and PPARM-NM-1 at the level of binding to shared genomic sites LXR, RXR, PPARalpha and RNA Polymerase II ChIP-seq on livers from female C57BL/6 wild-type and/or LXRM-NM-1/M-NM-2-deficient mice (13 weeks of age, n=1) treated by oral gavage once daily for 14 days with the RXR agonist bexarotene (100 mg/kg body weight [mpk], in 1% carboxymethylcellulose), the LXR agonist T0901317 (T09, 30 mpk) or vehicle alone.
2012-01-31 | E-GEOD-35262 | biostudies-arrayexpress
Project description:The nuclear receptors LXRa and LXRb play a crucial role in regulating hepatic lipid metabolism. Many genes induced in response to pharmacologic LXR agonism in mouse liver have been defined; however, the transcriptional consequences of loss of LXR binding to its genomic targets are not well characterized. Here we addressed how deletion of both LXRa and LXRb from mouse liver (LXRDKO) affects the transcriptional regulatory landscape by integrating changes in LXR/RXR binding, chromatin accessibility, and gene expression. Many genes involved in fatty acid metabolism have reduced expression and chromatin accessibility at their intergenic and intronic regions in LXRDKO livers. Genes that were upregulated in LXRDKO livers have increased chromatin accessibility in their promoter regions and are enriched for those with functions not linked to lipid metabolism. We further showed that loss of LXR binding in liver reduces the activity of a broad set of hepatic transcription factors, inferred through motif accessibility. In contrast, accessibility at promoter NFY motifs is strongly increased in the absence of LXR. Surprisingly, we define small set of direct target genes for ligand-dependent LXR repression. These genes with LXR binding sites show increased expression in LXRDKO liver and reduced expression in response to LXR agonist treatment. In summary, while our results support the established roles for LXRs as ligand-dependent activators of genes linked to lipid metabolism, the binding of LXR/RXR heterodimers to the hepatic genome has broad effects on the transcriptional landscape that extend beyond its canonical function as an activator of lipid metabolic genes.
2022-01-25 | GSE191030 | GEO
Project description:Genome-wide profiling of PPAR?:RXR and RNA polymerase II reveals temporal activation of distinct metabolic pathways in RXR dimer composition during adipogenesis. Chromatin immunoprecipitation combined with deep sequencing was performed to generate genome-wide maps of peroxisome prolifelator-activated receptor gamma (PPARg) and retinoid X receptor (RXR) binding sites, and RNA polymerase II (RNAPII) occupancy at high resolution throughout adipocyte differentiation of 3T3-L1 cells. The data provides the first positional and temporal map PPAR? and RXR occupancy during adipocyte differentiation at a global scale. The number of PPAR?:RXR shared binding sites is steadily increasing from D0 to D6. At Day6 there are over 5000 high confidence shared PPARy:RXR binding sites. We show that at the early days of differentiation several of these sites bind not only PPAR?:RXR but also other RXR dimers. The data also provides a comprehensive temporal map of RNAPII occupancy at genes throughout 3T3-L1 adipogenesis thereby uncovering groups of similarly regulated genes belonging to glucose and lipid metabolic pathways. The majority of the upregulated but very few downregulated genes have assigned PPAR?:RXR target sites, thereby underscoring the importance of PPAR?:RXR in gene activation during adipogenesis and indicating that a hitherto unrecognized high number of adipocyte genes are directly activated by PPAR?:RXR Examination of PPARg and RXR bindingsites during adipocyte differentiation (day 0 to 6) and association with transcription via RNAPII occupancy.
2008-12-10 | E-GEOD-13511 | biostudies-arrayexpress
Project description:Type II nuclear hormone receptors, such as FXR, LXR, and PPAR, which function in glucose and lipid metabolism and serve as drug targets for metabolic diseases, are permanently positioned in the nucleus regardless of the ligand status. Ligand activation of these receptors is thought to occur by co-repressor/co-activator exchange, followed by initiation of transcription. However, recent genome-wide location analysis showed that LXRα and PPARα binding in the liver is largely ligand-dependent. We hypothesized that pioneer factor Foxa2 evicts nucleosomes to enable ligand-dependent receptor binding. We show that chromatin accessibility, FXR binding and LXRα occupancy, and ligand-responsive activation of gene expression by FXR and LXRα require Foxa2. Unexpectedly, Foxa2 occupancy is drastically increased when either receptor, FXR or LXRα, is bound by an agonist. In addition, co-immunoprecipitation experiments demonstrate that Foxa2 interacts with either receptor in a ligand-dependent manner, suggesting that Foxa2 and the receptor bind DNA as an interdependent complex during ligand activation. Furthermore, PPARα binding is induced in Foxa2 mutants treated with FXR and LXR ligands, leading to activation of PPARα targets.
2021-07-12 | GSE149075 | GEO
Project description:Genome-wide profiling of PPARγ:RXR and RNA polymerase II reveals temporal activation of distinct metabolic pathways in RXR dimer composition during adipogenesis. Chromatin immunoprecipitation combined with deep sequencing was performed to generate genome-wide maps of peroxisome prolifelator-activated receptor gamma (PPARg) and retinoid X receptor (RXR) binding sites, and RNA polymerase II (RNAPII) occupancy at high resolution throughout adipocyte differentiation of 3T3-L1 cells. The data provides the first positional and temporal map PPARγ and RXR occupancy during adipocyte differentiation at a global scale. The number of PPARγ:RXR shared binding sites is steadily increasing from D0 to D6. At Day6 there are over 5000 high confidence shared PPARy:RXR binding sites. We show that at the early days of differentiation several of these sites bind not only PPARγ:RXR but also other RXR dimers. The data also provides a comprehensive temporal map of RNAPII occupancy at genes throughout 3T3-L1 adipogenesis thereby uncovering groups of similarly regulated genes belonging to glucose and lipid metabolic pathways. The majority of the upregulated but very few downregulated genes have assigned PPARγ:RXR target sites, thereby underscoring the importance of PPARγ:RXR in gene activation during adipogenesis and indicating that a hitherto unrecognized high number of adipocyte genes are directly activated by PPARγ:RXR
2008-12-10 | GSE13511 | GEO
Project description:The goal of the study was find the gene expression of diverse signaling pathways altered in Atp7b-/- mice (murine WD) liver as compared to control mice and how LXR agonist treatment will improve/ameliorate WD phenotype in Atp7b-/- mice. Activation of LXR/RXR using synthetic LXR agonist ameliorates liver inflammation and fibrosis in murine WD by changing gene expression.
2022-10-26 | GSE174015 | GEO
Project description:Gene expression: Identification of primary target genes of liver X receptor (LXR) in an immune-related cellular model (THP-1 cells) to study, in conjunction with LXR binding data from ChIP-seq, the genome-wide mechanisms of transcriptional regulation by LXR. ChIP-Seq: We performed ChIP-seq in macrophage-type PMA-differentiated THP-1 cells after stimulation with the potent synthetic LXR ligand T0901317 (T09). As a reference we performed microarray gene expression analysis in the same cellular model. We identified in total 1357 LXR binding locations on chromatin (FDR < 1%), of which 526 were observed after T09 treatment. De novo analysis of LXR site sequences identified DR4-type binding sites as major motif.
2012-02-02 | GSE28319 | GEO
Project description:Gene expression: Identification of primary target genes of liver X receptor (LXR) in an immune-related cellular model (THP-1 cells) to study, in conjunction with LXR binding data from ChIP-seq, the genome-wide mechanisms of transcriptional regulation by LXR. ChIP-Seq: We performed ChIP-seq in macrophage-type PMA-differentiated THP-1 cells after stimulation with the potent synthetic LXR ligand T0901317 (T09). As a reference we performed microarray gene expression analysis in the same cellular model. We identified in total 1357 LXR binding locations on chromatin (FDR < 1%), of which 526 were observed after T09 treatment. De novo analysis of LXR site sequences identified DR4-type binding sites as major motif. gene expression: THP-1 cells were treated for 4 h with 1 M-BM-5M T09 or vehicle (DMSO) ChIP-Seq: PMA-differentiated THP-1 cells were treated for 60 min with 1 M-BM-5M T09 or vehicle (DMSO)
2012-02-02 | E-GEOD-28319 | biostudies-arrayexpress
Project description:Aging is accompanied by physiological impairments, which, in insulin-responsive tissues, including the liver, predispose individuals to metabolic disease. However, the molecular mechanisms underlying these changes remain largely unknown. Here, we analyze genome-wide profiles of RNA and chromatin organization in the liver of young (3 months) and old (21 months) mice. Transcriptional changes suggest that de-repression of the nuclear receptors PPARα, PPARγ, and LXRα in aged mouse liver leads to activation of targets regulating lipid synthesis and storage, whereas age-dependent changes in nucleosome occupancy are associated with binding sites for both known regulators (forkhead factors and nuclear receptors) and for novel candidates associated with nuclear lamina (Hdac3 and Srf) implicated to govern metabolic function of aging liver. Winged-helix factor Foxa2 and nuclear receptor co-repressor Hdac3 exhibit reciprocal binding pattern at PPARα targets contributing to gene expression changes that lead to steatosis in aged liver. Genome-wide location analysis (ChIP-Seq) of Foxa2 and Hdac3 from young (3 months) and old (21 months) mouse livers
2014-10-23 | E-GEOD-60393 | biostudies-arrayexpress