Project description:The hypothesis tested is that IRF3 regulates adipogenesis and adipocyte function. Global gene expression of IRF3 wildtype (WT) and knockout (KO) adipocytes at different days during differentiation was compared. The results provide evidence on how IRF3 controls PPARg -regulated adipogenic program thereby regulate adipocyte differentiation.
Project description:Tight control of gene expression networks involved in adipose tissue formation and plasticity is required to adapt to energy needs and environmental cues. However, little is known about the mechanisms that orchestrate the dramatic transcriptional changes leading to adipocyte differentiation. We investigated the regulation of nascent transcription by SUMO during adipocyte differentiation using SLAMseq and ChIPseq. We discovered that SUMO has a dual function in differentiation; it supports the initial downregulation of pre-adipocyte-specific genes, while it promotes the establishment of the mature adipocyte transcriptional program. By characterizing SUMOylome dynamics in differentiating adipocytes by mass spectrometry, we found that SUMOylation of specific transcription factors like PPARG/RXR and chromatin modifiers promotes the transcription of adipogenic genes. Our data demonstrate that the sumoylation pathway helps coordinates the rewiring of transcriptional networks required for formation of functional adipocytes.
Project description:Obesity-induced inflammation metabolic dysfunction, but the mechanisms remain elusive. Here we showed that the innate immune factor IRF3 is a direct transcriptional regulator of glucose homeostasis through induction of endogenous FAHFA hydrolase Aig1 in adipocytes. Adipocyte-specific knockout IRF3 protects mice against high-fat diet-induced insulin resistance, whereas overexpression of IRF3 in adipocytes promotes insulin resistance on a high-fat diet. Furthermore, pharmacological inhibition of AIG1 reversed obesity-induced insulin resistance and restored glucose homeostasis in the setting of adipocyte IRF3 overexpression. We therefore, identify the adipocyte IRF3/AIG1 axis as a crucial link between obesity-induced inflammation and insulin resistance and suggest an approach for limiting the metabolic dysfunction accompanying obesity.
Project description:The diverse transcriptional mechanisms governing cellular differentiation and development of mammalian tissue remains poorly understood. Here we report that TAF7L, a paralogue of TFIID subunit TAF7, is enriched in adipocytes and mouse white fat tissue (WAT). Depletion of TAF7L reduced adipocyte-specific gene expression and compromised adipocyte differentiation as well as WAT development. Ectopic expression of TAF7L in myoblasts reprograms these muscle precursors into adipocytes upon induction. Genome-wide mRNA-seq expression profiling and ChIP-seq binding studies confirmed that TAF7L is required for activating adipocyte-specific genes via a dual mechanism wherein it interacts with PPARM-NM-3 at enhancers and TBP/Pol II at core promoters. In vitro binding studies confirmed that TAF7L forms complexes with both TBP and PPARM-NM-3. These findings suggest that TAF7L plays an integral role in adipocyte gene expression by targeting enhancers as a cofactor for PPARM-NM-3 and promoters as a component of the core transcriptional machinery. Genome-wide mapping of TAF7L and additional factors, and mRNA-seq expression profiling prior to and following mouse adipocyte differentiation.
Project description:Purpose: Interferon regulatory factor 3 (IRF3) is activated by pro-inflammatory cytokines, but its role in regulating adaptive thermogenesis and energy expenditure remains unclear. Here, we report that IRF3 as a negative transcription regulator of adaptive thermogenesis. Adipocyte-specific IRF3 knockout (FI3KO) attenuates HFD-induced obesity by increasing energy expenditure; further studies show that IRF3 suppresses adaptive thermogenesis through ISG15-mediated inhibition of glycolysis in adipocytes. Conversely, overexpression of IRF3 in adipocytes causes reduced thermogenesis gene expression, energy expenditure, and more persistent to HFD-induced obesity. Moreover, Isg15-/- increases adipose thermogenesis and protects mice from HFD-induced obesity and glucose intolerance. Taken together, these data indicate that IRF3 as a transcriptional regulator connecting between inflammatory signaling pathway and energy homeostasis Methods: primary adipocyte mRNA profiles of 8-week-old wild-type (WT) and FI3OE mice were generated by deep sequencing. The sequence reads that passed quality filters were analyzed at the transcript isoform level. qRT–PCR validation was performed using RT-PCR. Conclusions: Our study represents the first detailed analysis of adipocyte transcriptomes from WT and FI3OE iWAT, with biologic replicates, generated by RNA-seq technology. The optimized data analysis workflows reported here should provide a framework for comparative investigations of expression profiles. Our results show that Irf3 adipocyte-speficic overrxpression markedly increases the expression of Isg15 and Herc6, which play important role in regulation of glycolysis.
Project description:The interferon regulatory factors IRF3 and IRF7 are key players in the regulation of type I and III IFN genes. In this study, we analyzed the role of IRF3 and IRF7 for the host response to influenza A virus infections in Irf3-/-, Irf7-/- and Irf3-/-Irf7-/- knock-out mice.
Project description:FACS-purified adipocyte progenitors from murine subcutaneous adipose tissue were cultured under conditions promoting general adipogenic differentiation or beige/brite adipocyte differentiation (treatment with cPGI2). Time course expression profiling was performed during differentiation. In addition, some cultures of differentiated adipocytes were stimulated with norepinephrine for 3 hours. In parallel, differentiation and norepinephrine stimulation of progenitors from interscapular brown fat was performed and profiled.