GR accelerates, but is largely dispensable for, adipogenesis
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE76619 | GEO | 2016/11/01
SECONDARY ACCESSION(S): PRJNA308178
REPOSITORIES: GEO
Similar Datasets
Project description:Much of our knowledge on adipogenesis comes from cell culture models of preadipocyte differentiation. Adipogenesis is induced by treating confluent preadipocytes with the adipogenic cocktail, which activates transcription factors (TFs) glucocorticoid receptor (GR) and CREB within minutes and increases expression of TFs C/EBPb/d, KLF4 and Krox20 within hours. All of these TFs have been shown to be capable of promoting adipogenesis in culture when they are overexpressed. However, it has remained unclear whether endogenous KLF4 and Krox20 are required for adipogenesis in culture and in vivo. Using conditional knockout mice and derived white and brown preadipocytes, we show that endogenous KLF4 and Krox20 are dispensable for adipogenesis in culture and brown adipose tissue development in mice. In contrast, the master adipogenic TF PPARg is essential. These results challenge the existing model on transcriptional regulation in the early phase of adipogenesis and highlight the need of studying adipogenesis in vivo.
2016-11-17 | GSE87113 | GEO
Project description:GR accelerates, but is largely dispensable for, adipogenesis
| PRJNA308178 | ENA
Project description:Differentiation of 3T3-L1 preadipocytes can be induced by a 2-d treatment with a factor "cocktail" (DIM) containing the synthetic glucocorticoid dexamethasone (dex), insulin, the phosphodiesterase inhibitor methylisobutylxanthine (IBMX) and fetal bovine serum (FBS). We temporally uncoupled the activities of the four DIM components and found that treatment with dex for 48 h followed by IBMX treatment for 48 h was sufficient for adipogenesis, whereas treatment with IBMX followed by dex failed to induce significant differentiation. Similar results were obtained with C3H10T1/2 and primary mesenchymal stem cells. The 3T3-L1 adipocytes differentiated by sequential treatment with dex and IBMX displayed insulin sensitivity equivalent to DIM adipocytes, but had lower sensitivity to isoproterenol-stimulated lipolysis and reduced triglyceride content. The nondifferentiating IBMX–then-dex treatment produced transient expression of adipogenic transcriptional regulatory factors C/EBP{beta} and C/EBP{delta}, and little induction of terminal differentiation factors C/EBP{alpha} and PPAR{gamma}. Moreover, the adipogenesis inhibitor preadipocyte factor-1 (Pref-1) was repressed by DIM or by dex-then-IBMX, but not by IBMX-then-dex treatment. We conclude that glucocorticoids drive preadipocytes to a novel intermediate cellular state, the dex-primed preadipocyte, during adipogenesis in cell culture, and that Pref-1 repression may be a cell fate determinant in preadipocytes.
2008-07-25 | GSE11249 | GEO
Project description:PPARγ promotes adipogenesis while Wnt proteins inhibit adipogenesis. However, the mechanisms that control expression of these positive and negative master regulators of adipogenesis remain incompletely understood. By genome-wide histone methylation profiling in preadipocytes, we find that among gene loci encoding adipogenesis regulators, histone methyltransferase (HMT) G9a-mediated repressive epigenetic mark H3K9me2 is enriched on the entire PPARγ locus. H3K9me2 and G9a levels decrease during adipogenesis, which correlates inversely with induction of PPARγ. Removal of H3K9me2 by G9a deletion enhances chromatin opening and binding of adipogenic transcription factor C/EBP-beta to PPARγ promoter, which promotes PPARγ expression. Interestingly, G9a represses PPARγ expression in an HMT activity-dependent manner but facilitates Wnt10a expression independent of its enzymatic activity. Consistently, deletion of G9a or inhibiting G9a HMT activity promotes adipogenesis. Finally, deletion of G9a in mouse adipose tissues increases adipogenic gene expression and tissue weight. Thus, by inhibiting PPARγ expression and facilitating Wnt10a expression, G9a represses adipogenesis. Examination of gene expression changes in G9a KO brown preadipocytes
2013-02-01 | E-GEOD-41456 | biostudies-arrayexpress
Project description:Background: Exposure to the endocrine-disrupting chemical bisphenol A (BPA) is correlated with obesity and promotes adipogenesis of human preadipocytes into mature adipocytes. However, the mechanism of action of BPA-induced human adipogenesis in vitro remains to be fully characterized. Methods: In this study, potential mechanisms of BPA-induced adipogenesis in primary human preadipocytes were evaluated using gene expression microarray analysis. Preadipocytes from donors with normal body mass indexes were differentiated in the presence of 50 µM BPA or 1 µM dexamethasone (DEX) for 48 hours. Results: Microarray analysis revealed 235 up-regulated and 138 down-regulated genes following BPA treatment, including sterol regulatory element binding factor 1 (SREBF1), a key transcription factor known to regulate many components of lipid metabolism and adipogenesis. For DEX treated preadipocytes, 1136 genes were up-regulated, including the adipogenic marker lipoprotein lipase, while 1031 genes were down-regulated. Ingenuity Pathway Analysis was used to identify functional annotations of the gene expression changes associated with response to BPA and DEX treatments. BPA exposure was associated with expression changes in the genes involved in the accumulation of triacylglycerol while DEX was linked to metabolism of triacylglycerol and cleavage of fatty acids. The analysis also revealed enrichment of genes in pathways known to be associated with BPA exposure including thyroid-receptor/retinoic X receptor (TR/RXR) activation, mammalian target of rapamycin (mTOR) signaling and cholesterol biosynthesis, whereas DEX treatment was linked to cholesterol biosynthesis and ethanol degradation. Interestingly, alterations in the mTOR pathway in response to BPA did not occur in DEX-treated preadipocytes. Conclusions: Our data suggest that potential mechanisms of action of BPA-induced adipogenesis involve SREBF1, the TR/RXR and the mTOR pathways.
2014-04-15 | GSE56085 | GEO
Project description:The Wnt/b-catenin signaling inhibits adipogenesis. Genome-wide profiling studies have revealed the enrichment of histone H3K27 methyltransferase PRC2 on Wnt genes. However, the functional significance of such a direct link between the two types of developmental regulators in mammalian cells, and the role of PRC2 in adipogenesis, remain unclear. Here we show PRC2 and its H3K27 methyltransferase activity are required for adipogenesis. PRC2 directly represses Wnt1, 6, 10a and 10b genes in preadipocytes and during adipogenesis. Deletion of the enzymatic Ezh2 subunit of PRC2 eliminates H3K27me3 on Wnt promoters and de-represses Wnt expression, which leads to activation of Wnt/b-catenin signaling and inhibition of adipogenesis. Ectopic expression of the wild type Ezh2, but not the enzymatically inactive F667I mutant, prevents the loss of H3K27me3 and the defects in adipogenesis in Ezh2-/- preadipocytes. The adipogenesis defects in Ezh2-/- cells can be rescued by expression of adipogenic transcription factors PPARa, C/EBPb, or inhibitors of Wnt/b-catenin signaling. Interestingly, Ezh2-/- cells show marked increase of H3K27 acetylation globally as well as on Wnt promoters. These results indicate that H3K27 methyltransferase PRC2 directly represses Wnt genes to facilitate adipogenesis, and suggest that acetylation and trimethylation on H3K27 play opposing roles in regulating Wnt expression. To identify additional PRC2-regulated genes in preadipocytes, we performed microarray analysis in Ezh2flox/flox preadipocytes infected with retroviruses expressing Cre or vector alone.
2010-03-19 | E-GEOD-20054 | biostudies-arrayexpress
Project description:Insulin and IGF-1 promote adipocyte differentiation via complex and overlapping signalling networks. Here we used microarray analysis of brown preadipocytes derived from wild-type and insulin receptor substrate (IRS) knockout (KO) animals, which exhibited progressively impaired differentiation, to define the set of genes that predict adipogenic potential in these cells. 374 genes/ESTs were identified whose expression in preadipocytes correlated with their ultimate ability to differentiate. Many of these genes were related to early adipogenic events, including genes involved in extracellular matrix, cytoskeletal organization, growth arrest, post-mitotic clonal expansion, and inhibitors of adipogenesis, including preadipocyte factor-1 and multiple members of the Wnt-signalling pathway. Reconstitution of IRS-1 KO cells with IRS-1 reversed these changes and restored the ability to differentiate. Several of these genes showed concordant changes in brown adipose tissue in vivo. Necdin was markedly increased in IRS-1 KO cells that could not differentiate, and knockdown of necdin restored brown adipogenesis with down-regulation of Pref-1 and Wnt10a expression. We demonstrated a necdin-E2F4 interaction repressing PPARg transcription. IRS proteins regulated necdin via a CREB dependent pathway, defining a signalling network involved in brown preadipocyte determination.
2007-08-04 | E-GEOD-2556 | biostudies-arrayexpress
Project description:Differentiation of 3T3-L1 preadipocytes can be induced by a 2-d treatment with a factor "cocktail" (DIM) containing the synthetic glucocorticoid dexamethasone (dex), insulin, the phosphodiesterase inhibitor methylisobutylxanthine (IBMX) and fetal bovine serum (FBS). We temporally uncoupled the activities of the four DIM components and found that treatment with dex for 48 h followed by IBMX treatment for 48 h was sufficient for adipogenesis, whereas treatment with IBMX followed by dex failed to induce significant differentiation. Similar results were obtained with C3H10T1/2 and primary mesenchymal stem cells. The 3T3-L1 adipocytes differentiated by sequential treatment with dex and IBMX displayed insulin sensitivity equivalent to DIM adipocytes, but had lower sensitivity to isoproterenol-stimulated lipolysis and reduced triglyceride content. The nondifferentiating IBMX–then-dex treatment produced transient expression of adipogenic transcriptional regulatory factors C/EBP{beta} and C/EBP{delta}, and little induction of terminal differentiation factors C/EBP{alpha} and PPAR{gamma}. Moreover, the adipogenesis inhibitor preadipocyte factor-1 (Pref-1) was repressed by DIM or by dex-then-IBMX, but not by IBMX-then-dex treatment. We conclude that glucocorticoids drive preadipocytes to a novel intermediate cellular state, the dex-primed preadipocyte, during adipogenesis in cell culture, and that Pref-1 repression may be a cell fate determinant in preadipocytes. We sought to define the genes differentially expressed in response to dexamethasone (dex) in 3T3L1 mouse preadipocytes. We treated 3T3L1 cells with dex or DMSO vehicle for 2 or 36 hrs and then prepared total RNA. We hybridized each sample (Cy5) to a pool of the samples, which served as the reference (Cy3) channel. All linear models for differential gene expression were constructed with the "limma" package (Smyth, 2004) in BioConductor (Gentleman et al., 2004). A linear model for dex was constructed to compare the 4 biological replicates of DMSO vehicle treatment with dex treatment at either 2 or 36hr. Genes were considered differentially expressed if at least one probe had log-odds greater than 50:50 in the linear model.
2008-07-25 | E-GEOD-11249 | biostudies-arrayexpress
Project description:Background: Exposure to the endocrine-disrupting chemical bisphenol A (BPA) is correlated with obesity and promotes adipogenesis of human preadipocytes into mature adipocytes. However, the mechanism of action of BPA-induced human adipogenesis in vitro remains to be fully characterized. Methods: In this study, potential mechanisms of BPA-induced adipogenesis in primary human preadipocytes were evaluated using gene expression microarray analysis. Preadipocytes from donors with normal body mass indexes were differentiated in the presence of 50 M-BM-5M BPA or 1 M-BM-5M dexamethasone (DEX) for 48 hours. Results: Microarray analysis revealed 235 up-regulated and 138 down-regulated genes following BPA treatment, including sterol regulatory element binding factor 1 (SREBF1), a key transcription factor known to regulate many components of lipid metabolism and adipogenesis. For DEX treated preadipocytes, 1136 genes were up-regulated, including the adipogenic marker lipoprotein lipase, while 1031 genes were down-regulated. Ingenuity Pathway Analysis was used to identify functional annotations of the gene expression changes associated with response to BPA and DEX treatments. BPA exposure was associated with expression changes in the genes involved in the accumulation of triacylglycerol while DEX was linked to metabolism of triacylglycerol and cleavage of fatty acids. The analysis also revealed enrichment of genes in pathways known to be associated with BPA exposure including thyroid-receptor/retinoic X receptor (TR/RXR) activation, mammalian target of rapamycin (mTOR) signaling and cholesterol biosynthesis, whereas DEX treatment was linked to cholesterol biosynthesis and ethanol degradation. Interestingly, alterations in the mTOR pathway in response to BPA did not occur in DEX-treated preadipocytes. Conclusions: Our data suggest that potential mechanisms of action of BPA-induced adipogenesis involve SREBF1, the TR/RXR and the mTOR pathways. The study used 40 samples in total which included 5 replicates (cells from 5 unique donors) of 8 different treatments. The 8 treatments were as follows: 1) untreated (negative) control for 48 hours, 2) 25 uM BPA treated for 48 hours, 3) 50 uM BPA treated for 48 hours, 4) untreated (negative) control + insulin for 48 hours, 5) 25 uM BPA + insulin treated for 48 hours, 6) 50 uM BPA + insulin treated for 48 hours, 7) 1uM Dexamethasone + insulin treated for 48 hours, 8) 1uM Dexamethasone + insulin treated for 96 hours.
2014-04-15 | E-GEOD-56085 | biostudies-arrayexpress
Project description:Attainment of a brown adipocyte cell phenotype in white adipocytes, with their abundant mitochondria and increased energy expenditure potential, is a legitimate strategy for combating obesity. The unique transcriptional regulators of the primary brown adipocyte phenotype are unknown, limiting our ability to promote brown adipogenesis over white. In the present work, we used microarray analysis strategies to study primary preadipocytes, and we made the striking discovery that brown preadipocytes demonstrate a myogenic transcriptional signature, whereas both brown and white primary preadipocytes demonstrate signatures distinct from those found in immortalized adipogenic models. We found a plausible SIRT1-related transcriptional signature during brown adipocyte differentiation that may contribute to silencing the myogenic signature. In contrast to brown preadipocytes or skeletal muscle cells, white preadipocytes express Tcf21, a transcription factor that has been shown to suppress myogenesis and nuclear receptor activity. In addition, we identified a number of developmental genes that are differentially expressed between brown and white preadipocytes and that have recently been implicated in human obesity. The interlinkage between the myocyte and the brown preadipocyte confirms the distinct origin for brown versus white adipose tissue and also represents a plausible explanation as to why brown adipocytes ultimately specialize in lipid catabolism rather than storage, much like oxidative skeletal muscle tissue. Experiment Overall Design: Comparisons of white and brown pre- and mature-adiposytes
2009-04-08 | E-GEOD-7032 | biostudies-arrayexpress