Project description:The chronic inflammatory state that accompanies obesity is a major contributor to insulin resistance and other metabolic dysfunction features. Despite recent advances in our understanding of the cellular and secreted factors that promote the inflammatory milieu of obesity, we have much less insight into the transcriptional pathways that drive these processes. While most attention has focused on the canonical inflammatory transcription factor NF-KB, other potentially important factors exist, including members of the interferon regultory factor (IRF) family. Here we show that IRF3 expression is upregulated in the adipocytes of obese mice and humans. TLR3/TLR4 activation induces insulin resistance in adipocytes, which can be prevented by IRF3 knockdown. Furthermore, Irf3KO mice display improved insulin sensitivity, associated with reduced intra-adipose and systemic inflammation in the high-fat fed state, enhanced browning of subcutaneous fat, and increased adipose expression of Glut4. Taken together, our data indicates that IRF3 is a major transcriptional regulator of adipose inflammation to maintain systemic glucose and energy homeostasis. Transcriptional profiling of murine 3T3-L1 adipocytes with altered expression of IRF3. Overexpression or knockdown of IRF3 was achieved by lentivirus transduction for 6 days. 3T3-L1 adipocytes with IRF3 knockdown were further treated in the absence or presence of LPS for 6 days. Samples consist of triplicate replica with appropriate control.
Project description:Transcriptional profiling of mouse 3T3-L1 adipocytes. The objective of this study is to explore gene expression profiles of 3T3-L1 adipocytes in response to GDE5 siRNA transfection.
Project description:Differentiated 3T3-L1 adipocytes were either treated 0ng/ml or 500ng/ml rmIL-15 for 24 hours (n=3/group) qPCR gene expression profilling performed in vitro using recombinant murine (rm)IL-15 treated (500ng/ml) and untreated (control) 3T3-L1 cells. Equal amounts of total RNA per subject were used in the assay.
Project description:Snail1 is a transcriptional repressor required for a correct embryonic development. In cancer, Snail1 promotes the epithelial to mesenchymal transition in tumorigenic epithelial cells. In this work, we have analyzed the control of Snail1 in the differentiation of the 3T3-L1 cell line derived from murine embryo cells. The activation by snail of 3T3-L1 induced typical markers of cancer-activated fibroblasts as S100A4 or CD44. We generated 3T3-L1 cells stably over expressing Snail1 (3T3L1/Snail1) and control (3T3-L1/control) cells. We used SILAC quantitative approach to identify and characterize protein alterations induced by Snail1. Cells were fractionated in 5 subcellular fractions. The nuclear fraction of the cells was separated by 10% SDS-PAGE. Gels with forward and reverse experiments were stained with Coomassie Blue and cut into 18 slices prior to reduction, alkylation and digestion with trypsin. Tryptic peptides were scanned and fragmented with a linear ion trap-Orbitrap Velos (ThermoScientific). We identified a total of 3108 proteins, with 2572 quantified proteins, and 565 proteins modulated >1.5-fold by Snail1 overexpression. Among them, we found interesting up-regulated proteins associated to early differentiation of adipogenesis (C/EBPβ) and down-regulated proteins implicated in the final stages of differentiation to adipocytes (Fatty acid-binding protein or Fatty acid synthase). We also observed as down-regulated proteins important mediators of PPARγ pathway. We also observed downregulation of proteins implicated in mTOR, SRC and JAK/STAT pathway. We validated these proteomics data by western blot and qPCR in 3T3-L1 cells and other types of fibroblasts with capable to differentiate to terminal mesenchymal phenotypes, as well as in mesenchymal stem cells (MSC). This work provided insight into novel proteins with potential roles in the regulation of differentiation of the 3T3-L1 and MSCs as Nr2F6, ASC-1, Prrx1 or Cbx6. These candidates are down regulated due to the overexpression of Snail1 in 3T3-L1 cells. We next investigated the potential binding of Snail1 to promoter of these candidates. In silico analysis with MatInspector program revealed various putative E-box consensus motifs for Snail1. We performed ChIP and Luciferase assay to validate Snail1 binds to different E-box motifs of our candidates. Additionally, we analyzed the ability to prevent the differentiation to adipocytes of the 3T3-L1 cells using siRNAs. This work provided insight into novel proteins with potential roles in the regulation of differentiation to adipocytes of the 3T3-L1 and mMSC cells as Nr2F6, ASC-1, Prrx1 or Cbx6 controlled by Snail1.
Project description:Gene expression pattern in murine 3T3-L1 adipocytes treated with saturated fatty acid (palmitate) in the presence or absence of PI3K p110alpha-selective inhibitor A66.
Project description:Obesity is a known risk factor for breast cancer. To identify genes and underlying pathways in human breast cancer cells affected by interaction with mature adipocytes, two estrogen-receptor positive (ER+) breast cancer cell lines, MCF-7 and T47D, and the triple-negative (TN) breast cancer cell line MDA-MB-231 were cultivated in a co-culture system with or without differentiated murine 3T3-L1 adipocytes for the purpose of a microarray gene expression analysis. The use of in vitro differentiated 3T3-L1 adipocytes allowed comparable experimental conditions for each of the co-culture experiments with human breast cancer cell lines. For co-cultivation analyses of 3T3-L1 and breast cancer cells, we set up a two-dimensional transwell system, which enables intercellular communication through soluble factors secreted into the medium but inhibits intermixture of the different cell types. Following 5 days of co-culture with or without differentiated adipocytes, total RNA was isolated from the human breast cancer cells and subjected to microarray gene expression analyses.
Project description:Growing evidence indicates that PPARγ agonists, such as rosiglitazone (RSG,), induce adipose mitochondrial biogenesis. Using microarrays, we systematically analyzed nucleus-encoded mitochondrial gene expression in two common murine adipocyte models, 3T3 L1 and C3H/10T1/2 adipocytes, and aimed to further establish the direct role of RSG, and capture the temporal changes in mitochondrial gene transcription during this process. Experiment Overall Design: Fully differentiated 3T3 L1 and C3H/10T1/2 adipocytes were treated with RSG, or DMSO vehicle for 1, 2, 4, 7, 24, and 48 hrs, and total RNA was extracted for microarray analysis.