MDM2 facilitates adipocyte differentiation through CRTC-mediated activation of STAT3
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE82282 | GEO | 2016/06/07
SECONDARY ACCESSION(S): PRJNA324547
REPOSITORIES: GEO
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Project description:The ubiquitin ligase MDM2 is best known for balancing the activity of the tumor suppressor p53. We have previously shown that MDM2 is vital for adipocyte conversion through controlling Cebpd expression in a p53-independent manner. Here, we show that the proadipogenic effect of MDM2 relies on activation of the STAT family of transcription factors. Their activation was required for the cAMP-mediated induction of target genes. Interestingly, rather than influencing all cAMP-stimulated genes, inhibition of the kinases directly responsible for STAT activation, namely JAKs, or ablation of MDM2, each resulted in abolished induction of a subset of cAMP-stimulated genes, with Cebpd being among the most affected. Moreover, STATs were able to interact with the transcriptional cofactors CRTC2 and CRTC3, hitherto only reported to associate with the cAMP-responsive transcription factor CREB. Last but not least, the binding of CRTC2 to a transcriptional enhancer that interacts with the Cebpd promoter was dramatically decreased upon JAK inhibition. Our data reveal the existence of an unusual functional interplay between STATs and CREB at the onset of adipogenesis through shared CRTC cofactors.
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Project description:Forming biomolecular condensates by phase separation has recently emerged as a new principle for regulating gene expression in response to extracellular signaling. However, the molecular mechanisms underlying the coupling of signaling transduction and gene activation through condensate formation and how dysregulation of these mechanisms contributes to disease progression remain elusive. Here we report that CREB-regulated transcription coactivator 2 (CRTC2) translocates to nucleus and forms phase-separated condensates upon activation of cAMP signaling. We show that CRTC2 interacts with positive transcription elongation factor b (P-TEFb), and cAMP-induced CRTC2 condensate formation activates P-TEFb by extracting P-TEFb from its inhibitory complex. Aberrantly elevated cAMP signaling plays central roles in the development of autosomal dominant polycystic kidney disease (ADPKD). We demonstrate that, in contrast to a dispersed cytosolic distribution in the normal tubular epithelia cells, CRTC2 localizes in nucleus and forms condensates in cystic epithelial cells of mouse and human ADPKD kidneys. We show that genetic depletion of CRTC2 markedly suppresses cyst growth in an orthologous ADPKD mouse model. Using integrative transcriptomic and cistromic analyses, we identify CRTC2-regulated cystogenic genes, whose activation depends on CRTC2 condensation-facilitated P-TEFb recruitment and RNA polymerase II pausing release. Together, our findings elucidate a mechanism by which CRTC2 nuclear condensation conveys cAMP signaling to transcription elongation activation and promotes cystogenesis in ADPKD.
2021-12-28 | GSE173693 | GEO
Project description:Forming biomolecular condensates by phase separation has recently emerged as a new principle for regulating gene expression in response to extracellular signaling. However, the molecular mechanisms underlying the coupling of signaling transduction and gene activation through condensate formation and how dysregulation of these mechanisms contributes to disease progression remain elusive. Here we report that CREB-regulated transcription coactivator 2 (CRTC2) translocates to nucleus and forms phase-separated condensates upon activation of cAMP signaling. We show that CRTC2 interacts with positive transcription elongation factor b (P-TEFb), and cAMP-induced CRTC2 condensate formation activates P-TEFb by extracting P-TEFb from its inhibitory complex. Aberrantly elevated cAMP signaling plays central roles in the development of autosomal dominant polycystic kidney disease (ADPKD). We demonstrate that, in contrast to a dispersed cytosolic distribution in the normal tubular epithelia cells, CRTC2 localizes in nucleus and forms condensates in cystic epithelial cells of mouse and human ADPKD kidneys. We show that genetic depletion of CRTC2 markedly suppresses cyst growth in an orthologous ADPKD mouse model. Using integrative transcriptomic and cistromic analyses, we identify CRTC2-regulated cystogenic genes, whose activation depends on CRTC2 condensation-facilitated P-TEFb recruitment and RNA polymerase II pausing release. Together, our findings elucidate a mechanism by which CRTC2 nuclear condensation conveys cAMP signaling to transcription elongation activation and promotes cystogenesis in ADPKD.
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Project description:Obesity stimulates the infiltration of adipose tissue by innate immune cells, which in turn promote insulin resistance via the NFkB mediated induction of pro-inflammatory cytokines, which interfere with triglyceride metabolism. The cAMP responsive factor CREB has also been implicated in adipose tissue inflammation and insulin resistance, although the underlying mechanism is unclear. Here, we show that high fat diet (HFD) feeding triggers activation of the CREB cofactors CRTC2 and CRTC3, which bind to CREB and mediate induction of CXCL1 and other cytokine genes in cooperation with NFkB. HFD feeding reduced adipocyte C/EBPa expression in adipose, leading to decreases in the expression of Salt Inducible Kinase 2 (SIK2), which otherwise phosphorylates and sequesters CRTCs in the cytoplasm. Depletion of SIK2 in adipose led to dephosphorylation of CRTC2 and CRTC3 (CRTC2/3) and to the induction of CXCL1 and other cytokine genes in adipocytes. Indeed, CRTC2/3 were found to stimulate the expression of a subset of cellular genes cooperatively with NF-kB in adipocytes. Knockout of both CRTC2 and CRTC3 in adipose decreased the expression of CXCL1/2 and thereby reduced neutrophil and macrophage infiltration. As depletion of CXCL1/2, with neutralizing antiserum or by KO of the CXCL1 gene restored glucose tolerance and insulin sensitivity in the setting of diet induced obesity, our results demonstrate that NF-kB and CREB/CRTC pathways modulate adipose tissue function in part via cooperative effects on target gene expression.
2021-10-27 | GSE160597 | GEO
Project description:Formation of biomolecular condensates by phase separation has recently emerged as a new principle for regulating gene expression in response to extracellular signaling. However, the molecular mechanisms underlying the coupling of signal transduction and gene activation through condensate formation, and how dysregulation of these mechanisms contributes to disease progression, remain elusive. Here we report that CREB-regulated transcription coactivator 2 (CRTC2) translocates to the nucleus and forms phase-separated condensates upon activation of cAMP signaling. We show that intranuclear CRTC2 interacts with positive transcription elongation factor b (P-TEFb) and activates P-TEFb by disrupting the inhibitory 7SK snRNP complex. Aberrantly elevated cAMP signaling plays central roles in the development of autosomal dominant polycystic kidney disease (ADPKD). We find that CRTC2 localizes to the nucleus and forms condensates in cystic epithelial cells of both mouse and human ADPKD kidneys. Genetic depletion of CRTC2 suppresses cyst growth in an orthologous ADPKD mouse model. Using integrative transcriptomic and cistromic analyses, we identify CRTC2-regulated cystogenesis-associated genes, whose activation depends on CRTC2 condensate-facilitated P-TEFb recruitment and the release of paused RNA polymerase II. Together, our findings elucidate a mechanism by which CRTC2 nuclear condensation conveys cAMP signaling to transcription elongation activation and thereby promotes cystogenesis in ADPKD.
2021-12-28 | GSE173695 | GEO
Project description:Although persistent elevations in circulating glucose concentrations promote compensatory increases in pancreatic islet mass, unremitting insulin resistance causes a deterioration in beta cell function that disrupts glucose balance and signals the progression to diabetes 1. Glucagon like Peptide 1 (GLP1) agonists improve glucose tolerance in insulin resistance, although some individuals are unresponsive to treatment. Here we show that increases in GLP1 during feeding promote beta cell function in part through the PKA-mediated activation of CREB and its coactivator CRTC2 2. Mice with a knockout of CRTC2 in beta cells have impaired oral glucose tolerance due to decreases in circulating insulin concentrations. CRTC2 was found to promote beta cell function in part by stimulating the expression of the transcription factor MafA. Chronic hyperglycemia associated with high fat or high carbohydrate diet feeding disrupted cAMP signaling in pancreatic islets. Indeed, prolonged elevations in circulating glucose concentrations interfered with CREB signaling by activating the mTOR pathway and triggering the hypoxia inducible factor (HIF1)-dependent induction of the Protein Kinase A Inhibitor beta (PKIB), a potent inhibitor of PKA catalytic activity 3. As disruption of the PKIB gene restored glucose tolerance and insulin secretion in obesity, our results demonstrate how cross-talk between nutrient and hormonal pathways contributes to loss of pancreatic islet function in insulin resistance. Rat insulinoma cells were used to interrogate the impact of glucose exposure and CREB activity on cAMP dependent gene regulation in the pancreatic beta cells
2015-02-23 | E-GEOD-60158 | biostudies-arrayexpress
Project description:We attempted to analyze the effect of adipocyte-specific knockout of Crtc2 in in aging. By analyzing the transcriptomics of epididymal primary adipocytes from male mice with wild type and adipocyte-specific Crtc2 knockout mice in response to aging, we provide the insight into the collective roles of Crtc2 in epididymal white adipose tissues upon aging.
2022-07-09 | GSE207433 | GEO
Project description:In this study we show that, in embryonic fibroblasts from mice on a high fat diet and treated with Forskolin, ionizing radiation exposure or both, phosphorylation of CREB-binding protein (CREB) by ATM (ataxia-telangiectasia-mutated) and casein kinases 1 and 2 (CK1 and CK2) on a cluster of five phosphorylation sites (the ATM/CK cluster) within the unstructured kinase-inducible domain (KID) provides an additional level of regulation through dynamic modulation of CREB DNA binding activity. Stoichiometric phosphorylation of the ATM/CK cluster in response to DNA damage inhibited cAMP-induced CREB target gene expression, CREB DNA binding activity, and CREB-CRTC2-DNA ternary complex formation proportional to the number of phosphate residues modified. Substoichiometric phosphorylation of the ATM/CK cluster promoted cAMP/Ca2+-regulated transcriptional coactivators (CRTCs) recruitment and CREB activation via an ATM-independent, PKA-dependent pathway. Mice expressing a non-phosphorylatable CREBS111A allele exhibited phenotypes consistent with CREB deregulation, including fasting hyperglycemia, susceptibility to diet-induced obesity, and reduced expression of gluconeogenic genes. Two genotypes: CREB+/+ (wild type) and CREBS111A (non-phosphorylatable CREB KID S111A mutant allele) each control treated, exposed to forskolin, ionizing radiation or both in triplicate and in two batches toataling 48 arrays
2016-07-01 | E-GEOD-83891 | biostudies-arrayexpress
Project description:Obesity is a major risk factor for the development of type II diabetes. Increases in adipose tissue mass trigger insulin resistance via the release of pro-inflammatory cytokines from adipocytes and macrophages. CREB and the CRTC coactivators have been found to promote insulin resistance in obesity, although the mechanism is unclear. Here we show that high fat diet feeding activates the CREB/CRTC pathway in adipocytes by decreasing the expression of SIK2, a Ser/Thr kinase that phosphorylates and inhibits CRTCs. SIK2 levels are regulated by the adipogenic factor C/EBPα, whose expression is reduced in obesity. Exposure to PPARγ agonist rescues C/EBPα expression and restores SIK2 levels. CRTC2/3 promote insulin resistance via induction of the chemokines CXCL1/2. Knockout of CRTC2/3 in adipocytes reduces CXCL1/2 expression and improves insulin sensitivity. As administration of CXCL1/2 reverses salutary effects of CRTC2/3 depletion, our results demonstrate the importance of the CREB/CRTC pathway in modulating adipose tissue function.
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Project description:The MDM2 oncoprotein is an essential component of the p53 pathway. Although MDM2 has been widely described as a major negative regulator of the p53 tumor suppressor, growing evidences support the notion that Mdm2 functions are also mediated through p53 independent mechanisms. We found that MDM2 is recruited on chromatin. By ChIP-Seq (using MDM2 antibody) of H1299 cells exhibiting MDM2 recruitment on chromatin, we identified at the whole genome level MDM2 binding sites. Both input and IPped-DNA were exhaustively sequenced and mapped on human genome
2016-06-09 | GSE64439 | GEO