Glucocorticoid Signaling Defines a Novel Commitment State during Adipogenesis In Vitro
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE11249 | GEO | 2008/07/25
SECONDARY ACCESSION(S): PRJNA106755
REPOSITORIES: GEO
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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: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: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. Keywords = brown fat Keywords = preadipocyte Keywords = adipogenesis Keywords = mouse Keywords: parallel sample
2005-06-01 | GSE2556 | GEO
Project description:We profiled PPARg dependent gene expression changes during differntiation of 3T3L1 cell using PPARg siRNA 3T3-L1 (Pre-adipocyte) cell line was induced to differentiate using standard adipocyte differentiation media (IBMX, Dex and Insulin) 48hrs post-confluency. RNA was harvested at day -2 (confluent fibroblasts), 48hrs post-induction with IBMX, DEX and Insulin (day=0) and for each subsequent day after rosiglitazone treatment. Illumina beadchip microarrays were used to determine expression profiles of genes differentially regulated in cells transfected with either siRNA targeting PPARgamma or a non-targeting control siRNA.
2009-03-24 | GSE12929 | GEO
Project description:PPAR? 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 PPAR? locus. H3K9me2 and G9a levels decrease during adipogenesis, which correlates inversely with induction of PPAR?. Removal of H3K9me2 by G9a deletion enhances chromatin opening and binding of adipogenic transcription factor C/EBP-beta to PPAR? promoter, which promotes PPAR? expression. Interestingly, G9a represses PPAR? 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 PPAR? expression and facilitating Wnt10a expression, G9a represses adipogenesis. Examination of 3 different histone modification changes in 3T3-L1 preadipocytes
2013-02-01 | E-GEOD-41455 | 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:Dexamethasone (DEX), a synthetic ligand for glucocorticoid receptor (GR), is routinely used to stimulate adipogenesis in culture. GR-depleted preadipocytes show adipogenesis defects one week after induction of differentiation. However, it has remained unclear whether GR is required for adipogenesis in vivo. By deleting GR in precursors of brown adipocytes, we found unexpectedly that GR is dispensable for brown adipose tissue development in mice. In culture, GR-deficient primary or immortalized white and brown preadipocytes showed severely delayed adipogenesis one week after induction of differentiation. However, when differentiation was extended to 3 weeks, GR-deficient preadipocytes showed similar levels of adipogenesis marker expression and lipid accumulation as the wild type cells, indicating that DEX-bound GR accelerates, but is dispensable for, adipogenesis. Consistently, DEX accelerates, but is dispensable for, adipogenesis in culture. We show that DEX-bound GR accelerates adipogenesis by directly promoting the expression of adipogenic transcription factors C/EBPb, C/EBPd, C/EBPa, KLF5, KLF9 and PPARg in the early phase of differentiation. Mechanistically, DEX-bound GR recruits histone H3K27 acetyltransferase CBP to promote activation of C/EBPb-primed enhancers of adipogenic genes. These results clarify the role of GR in adipogenesis in vivo and demonstrate that DEX-mediated activation of GR accelerates, but is dispensable for, adipogenesis.
2016-11-01 | GSE76619 | GEO
Project description:We profiled PPARg dependent gene expression changes during differntiation of 3T3L1 cell using PPARg siRNA 3T3-L1 (Pre-adipocyte) cell line was induced to differentiate using standard adipocyte differentiation media (IBMX, Dex and Insulin) 48hrs post-confluency. RNA was harvested at day -2 (confluent fibroblasts), 48hrs post-induction with IBMX, DEX and Insulin (day=0) and for each subsequent day after rosiglitazone treatment. Illumina beadchip microarrays were used to determine expression profiles of genes differentially regulated in cells transfected with either siRNA targeting PPARgamma or a non-targeting control siRNA. 3T3L1 cell were induced to differentiate into adipocytes using IBMX, DEX and Insulin. RNA from cell treated with PPARg-specific siRNA and non-specific siRNA was isolated at different timepoints. Illumina MouseRef-8 v1.1 Bead chips were used for expression profiling
2010-04-08 | E-GEOD-12929 | biostudies-arrayexpress
Project description:In this study we evaluated the role of hyaluronan (HA) in reactive adipogenesis, a local expansion of preadipocytes that provides host defense by release of antimicrobial peptides. We observed that HA accumulated during maturation of adipocytes in vitro and was associated with increased expression of preadipocyte factor 1 (Pref-1), Zinc finger protein 423 (Zfp423) and early B cell factor 1 (Ebf1). Although HA is normally abundant in the extracellular matrix, a further increase in HA staining occurred in mice at sites of reactive adipogenesis following injury of colon by dextran sodium sulfate or injury of skin from infection with S. aureus. HA also abundantly accumulated around adipocytes seen in the colon of patients with inflammatory bowel disease. This HA was necessary for adipocyte maturation since digestion of HA by administration of soluble hyaluronidase or transgenic expression of hyaluronidase 1 inhibited adipogenesis in vitro and in vivo. Furthermore, hyaluronidase also suppressed inflammation of both skin and colon and decreased antimicrobial peptide expression by developing preadipocytes. This resulted in increased bacterial transit across the epithelial barrier despite decreased tissue injury from inflammation. These observations suggest HA plays an important role in reactive adipogenesis and host defense after injury.
2018-09-13 | GSE119826 | GEO
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