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
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.
Project description:Developmental transitions are guided by master regulatory transcription factors. During adipogenesis, a transcriptional cascade culminates in expression of PPARg and C/EBPa, which orchestrate activation of the adipocyte gene expression program. However, the coactivators controlling PPARg and C/EBPa expression are less well characterized. Here we show the bromodomain-containing protein, BRD4, regulates transcription of PPARg and C/EBPa. Analysis of BRD4 chromatin occupancy reveals that induction of adipogenesis in 3T3L1 fibroblasts provokes dynamic redistribution of BRD4 to de novo super enhancers proximal to genes controlling adipocyte differentiation. BET bromodomain inhibition impedes BRD4 occupancy at these de novo enhancers and disrupts transcription of Pparg and Cebpa, thereby blocking adipogenesis. Furthermore, silencing of these BRD4-occupied distal regulatory elements at the Pparg locus by CRISPRi demonstrates a critical role for these enhancers in the control of Pparg gene expression and adipogenesis in 3T3L1s. Together, these data establish BET bromodomain proteins as time- and context-dependent coactivators of the adipocyte cell state transition.
Project description:We report the robustness and plasticity of the differentiation potential of 3T3L1 adipocytes in the aspect of genome-wide change of chromatin structure by ectopic expression of Pax7 and classifying the genes potentially responsible for facilitating or suppressing trans-differentiation of 3T3L1 in the aspect of epigenetic regulation..
Project description:The discreteness of cell fates is an inherent and fundamental feature of multicellular organisms. Here we show that cross-antagonistic mechanisms of actions of MyoD and PPARg, which are the master regulators of muscle and adipose differentiation, respectively, confer the robustness to the integrity of cell differentiation. Simultaneous expression of MyoD and PPARg in mesenchymal stem/stromal cells led to the generation of a mixture of multinucleated myotubes and lipid-filled adipocytes. Interestingly, hybrid cells, i.e., lipid-filled myotubes, were not generated, suggesting that these differentiation programs are mutually exclusive. Mechanistically, while exogenously expressed MyoD was rapidly degraded in adipocytes through ubiquitin-proteasome pathways, exogenously expressed PPARg was not down-regulated in myotubes. In PPARg-expressing myotubes, PPARg-dependent histone hyperacetylation was inhibited in a subset of adipogenic gene loci, including that of C/EBPa, an essential effector of PPARg. Thus, the cross-repressive interactions between MyoD- and PPARg-induced differentiation programs ensure the discrete cell fate decisions. To gain insights into the mechanisms by which adipogenic differentiation is inhibited in PPARg-expressing myotubes, we performed microarray analysis to compare gene expression profiles of the myotube-enriched (M) fraction and the adipocyte-enriched (A) fraction. M fraction and A fraction were obtained by fractionating a mixture of myotubes and adipocytes, which was generated by simultaneous expression of MyoD and PPARg, according to cell size.