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. Keywords: cell type comparison, Gata2, PPAR gamma, adipocyte, preadipocytes, differentiation
Project description:Here we conducted a comprehensive analysis of the proteome of the widely used 3T3-L1 murine adipocyte laboratory cell line at 10-days post-differentiation.
Project description:Metabolic syndrome is an important public concern and demand for effective therapeutic strategies. Abdominal obesity, especially an increase in the visceral adipose tissue, is the main cause of this syndrome. Flavonoids are expected to improve risk factors for metabolic syndrome. Bilberry, original species of blueberry containing anthocyanidin flavonoids have been used for centuries in Europe to ameliorate the symptoms of diabetes, but their effects and the mechanisms on lipid accumulation of adipocyte cells are not well defined. In the present study, we investigated effects of the Bilberry extract on differentiation of adipocytes using 3T3-L1 adipocyte cell line. Exposure to Bilberry extract during the early period of adipogenesis (6 days) was significantly inhibited adipocyte differentiation of 3T3-L1. During this period, Bilberry extract greatly down-regulated the mRNA levels of the key adipogenesis-associated markers peroxisome proliferator-activated receptor-γ (PPARγ). Furthermore, Bilberry extract significantly decreased expression of the transcription factor Sterol Regulatory Element Binding Protein 1c (SREBP1c), which plays a central role in adipocyte differentiation including the induction of PPARγ. The expression of SREBP1c is remarkably enhanced in response to insulin, thus raises the possibility that Bilberry extract might inhibit the Insulin pathway. So, We investigated whether Billberry extract and anthocyanidines turned the insulin signaling pathway using microarray. As a result, Gene Set Enrichment Analysis (GSEA) shows that these additives turned insulin signaling pathway certainly. We quantified expression profiles of whole mRNAs by microarray in the adipocyte from 3T3-L1 with or without additives. 3T3-L1 preadipocytes (American Type Culture Collection, Manassas, VA) were grown to confluence in DMEM media (Sigma Aldrich, Tokyo, Japan) with 10% calf serum and penicillin (100 U/ml)/streptomycin (100 ug/ml). Adipogenesis was induced using an adipogenesis assay kit (Chemicon International, Temecula, CA). On day 0, cells were induced with initiation media (10 ug/ml insulin, 1 uM dexamethasone and 0.5 uM IBMX in DMEM media added with 1: 0.1% DMSO, 2: 100 ug/ml Bilberry extract, 3: 100 nM Delphinidin or 4: 100 nM Cyanidin (total 4 samples). On day 2, harvested the cells, extracted total RNA and did microarray experiments.
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:Cebpa is a critical transcription factor gene for adipocyte differentiation and adipose tissue development. However, mechanisms controlling Cebpa expression during adipogenic differentiation remain largely unknown. Here, we generated the high-resolution chromatin interaction maps of Cebpa in 3T3-L1 preadipocytes (3T3-L1) and 3T3-L1 adipocytes (3T3-L1-AD) using circularized chromosome conformation capture coupled with next-generation sequencing (4C-seq), and characterized differences in their chromatin interactomes and chromatin status of the interaction sites during adipogenic differentiation. We performed a 4C-seq experiment on inguinal white adipose tissue (iWAT) to evaluate whether chromatin interaction between Cebpa-L1-AD-En2 and Cebpa promoters in 3T3-L1 adipocytes also exists in mouse adipose tissue.
Project description:Adiponectin is known as a key molecule to ameliorate symptoms of the type 2 diabetes mellitus and disorder of lipid metabolism. In this study, we investigated whether hot water extracts of some livestock by-products induced expression of adiponectin using 3T3-L1 adipocytes. Out of 11 extracts tested, pig testis extracts (PT) enhanced adiponectin mRNA expression and secretion of adiponectin protein from 3T3-L1 cells. Furthermore, simultaneous treatment with PT and daidzein, soy phytoestrogen, enhanced synergistically adiponectin secretion. Moreover, pretreatment with an estrogen receptor β (ERβ) antagonist (PHTPP) diminished adiponectin secretion in daidzein treated cell, but not in PT treated cells. Transcriptome analyses revealed that daidzein and PT commonly regulated PPAR signaling pathway, although gene expression was differently regulated in PT-treated cells and daidzein-treated cells. The expression of 476 and 380 genes significantly up-regulated in daidzein and PT treatment, although commonly regulated genes were only 86 genes. These results suggested that PT may ameliorate lipid metabolic dysfunction via promote adipocytes differentiation and enhance adiponectin secretion through different mechanism from daidzein.
Project description:Genome-wide profiling of PPAR?: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 PPAR? and RXR occupancy during adipocyte differentiation at a global scale. The number of PPAR?: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 PPAR?: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 PPAR?:RXR target sites, thereby underscoring the importance of PPAR?:RXR in gene activation during adipogenesis and indicating that a hitherto unrecognized high number of adipocyte genes are directly activated by PPAR?:RXR Examination of PPARg and RXR bindingsites during adipocyte differentiation (day 0 to 6) and association with transcription via RNAPII occupancy.