14-3-3ζ controls adipocyte progenitor cell cycle and differentiation via Gli3-dependent p27Kip expression
ABSTRACT: 14-3-3 proteins facilitate cytoplasmic-nuclear shuttling of transcription factors.Adipocyte differentiation requires the function of critical transcription factors to drive the development of a mature adipocyte. The aim of the study was to investigate if 14-3-3ζ is required for the adipogenic transcriptional program. Examination of the transcriptome in siCon- and si14-3-3ζ-transfected 3T3-L1 cells undergoing differentiation at t=0, 24, and 48 hours.
Project description:Using RNA-Seq, we compared the transcriptomes of differentiated 3T3-L1 adipocytes for control and ZFP407-deficient cells Differentiated 3T3-L1 cells were electroporated with control or 1 of 2 Zfp407 siRNAs. Six independent siRNA electroporations were conducted for the control siRNA and 3 independent electroporations were conducted for each Zfp407 siRNA.
Project description:To elucidate the signalling network responsible for mediating the effects of FGF21, we quantified the dynamic phosphoproteome of adipocytes following acute exposure to this hormone. A major FGF21-regulated signalling node was mTORC1/S6K. In contrast to insulin, we find that FGF21 activates mTORC1 via MAPK signalling rather than through the canonical PI3K/AKT pathway. This study provides a systems view of FGF21 signalling and reveals a new role for mTORC1 in maintaining nutrient homeostasis.
Project description:Here, we have used digital genomic footprinting to precisely define protein localization for several adipogenic transcription factors at a genome-wide level. In combination with ChIP-seq data, these analyses reveal novel molecular insight into the organization of transcription factors at hotpot regions, which provides a new framework for understanding transcription factor cooperativity on chromatin. Digital genomic footprinting and gene expression in 3T3-L1 pre-adipocytes by high throughput sequencing.
Project description:Insulin is a potent regulator of protein metabolism. Here we describe a time-resolved map of insulin-regulated protein turnover in 3T3-L1 adipocytes using metabolic pulse-chase labelling and high-resolution mass spectrometry.
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 Examination of PPARg and RXR bindingsites during adipocyte differentiation (day 0 to 6) and association with transcription via RNAPII occupancy.
Project description:miRNA profiles of adipocyte-derived microvesicles (ADMs) on the Day 2-4 and Day 8-10 were compared. ADMs were prepared from the 48h-conditioned medium of 3T3-L1 adipocytes (Day 2-4 and Day 8-10) followed by RNA isolation.
Project description:The demand for novel three-dimensional (3D) cell culture models of adipose tissue has been increasing, and proteomic investigations are important for determining the underlying causes of obesity, type II diabetes, and metabolic disorders. In this study, we performed global quantitative proteomic profiling of three 3D-cultured 3T3-L1 cells (preadipocytes, adipocytes and co-cultured adipocytes with macrophages) and their 2D-cultured counterparts using 2D-nanoLC-ESI-MS/MS with iTRAQ labelling. A total of 2,885 shared proteins from six types of adipose cells were identified and quantified in four replicates. Using iTRAQ-based quantitative assessments, we found that the primary proteins involved in carbohydrate and fatty acid metabolism, adipogenesis and the electron transport chain were highly expressed in 3D cell culture system when compared to those of 2D-cultured cells. Furthermore, it was also shown that the expression levels of proteins associated with metabolic pathways, carbon metabolism and glycolysis/gluconeogenesis were up-regulated, whereas proteins implicated in both DNA replication and the cell cycle were expressed at lower levels compared to those of the 2D mono-cultured cells. Based on these results, the 3D adipocyte model can help elucidate the mechanisms underpinning metabolic syndromes and aid the development of new medical treatments for metabolic disorders.
Project description:The nuclear receptor PPAR gamma is required for adipocyte differentiation, but its role in mature adipocytes is less clear. Here we report that knockdown of PPAR gamma expression in 3T3-L1 adipocytes returned the expression of most adipocyte genes towards preadipocyte levels. Consistently, down regulated but not up regulated genes showed strong enrichment of PPAR gamma binding. Surprisingly, not all adipocyte genes were reversed and the adipocyte morphology was maintained for an extended period after PPAR gamma depletion. To explain this, we focused on transcriptional regulators whose adipogenic regulation was not reversed upon PPAR gamma depletion. We identified GATA2, a transcription factor whose down-regulation early in adipogenesis is required for preadipocyte differentiation, remaining low after PPAR gamma knockdown. Forced expression of GATA2 in mature adipocytes complemented PPAR gamma depletion and impaired adipocyte functionality with a more preadipocyte- like gene expression profile. Ectopic expression of GATA2 in adipose tissue in vivo had similar effect on adipogenic gene expression. These results suggest that PPAR gamma-independent down regulation of GATA2 prevents reversion of mature adipocytes after PPAR gamma depletion. Experiment Overall Design: This dataset consists of three sample groups: preadipocytes, control siRNA treated adipocytes, and PPAR gamma siRNA treated adipocytes. Each sample group consists of three replicates samples. Each sample was hybridized to a separate array for a total of nine arrays. Experiment Overall Design: Technical replicates: Pread 1, Pread 2, Pread 3 Experiment Overall Design: Technical replicates: Cont siRNA 1, Cont siRNA 2, Cont siRNA 3 Experiment Overall Design: Technical replicates: PPAR gamma siRNA 1, PPAR gamma siRNA 2, PPAR gamma siRNA 3
Project description:ChIP-seq data from mouse adipocyte. Mature 3T3-L1 adipocytes were cross-linked with 1% formaldehyde 10 days after induction with MDI. Frozen cell pellets were submitted to the Broad Institute for subsequent analysis of Ebf1-bound regions using anti-Ebf1 antibody (Abnova H00001879-M01).
Project description:The transcriptional mechanisms by which temporary exposure to developmental signals instigates adipocyte differentiation are unknown. During early adipogenesis, we find transient enrichment of the glucocorticoid receptor (GR), CCAAT/enhancer binding protein b (CEBPb), p300, mediator subunit 1, and histone H3 acetylation near genes involved in cell proliferation, development and differentiation, including the gene encoding the master regulator of adipocyte differentiation, peroxisome proliferator activated receptor g2 (PPARg2). Occupancy and enhancer function are triggered by adipogenic signals, and diminish upon their removal. GR, which is required for adipogenesis but need not be active in the mature adipocyte, transiently functions with other enhancer proteins to propagate a new program of gene expression that includes induction of PPARg2, thereby providing a memory of the earlier adipogenic signal. Thus, the conversion of preadipocyte to adipocytes involves the formation of an epigenomic transition state that is not observed in cells at the beginning or end of the differentiation process. Genomic occupancy profiled by high throughput sequencing (ChIP-seq) from 3T3-L1 cells during differentiation for H3K9Ac, CEBPb and GR.