ABSTRACT
Enhancing brown fat activity and promoting white fat browning are attractive therapeutic strategies for treating obesity and associated metabolic disorders. To provide a comprehensive picture of the gene regulatory network in these processes, we conducted a series of transcriptome studies by RNA sequencing (RNA-seq) and quantified the mRNA and long noncoding RNA (lncRNA) changes during white fat browning (chronic cold exposure, beta-adrenergic agonist treatment, and intense exercise) and brown fat activation or inactivation (acute cold exposure or thermoneutrality, respectively). mRNA-lncRNA coexpression networks revealed dynamically regulated lncRNAs to be largely embedded in nutrient and energy metabolism pathways. We identified a brown adipose tissue-enriched lncRNA, lncBATE10, that was governed by the cAMP-cAMP response element-binding protein (Creb) axis and required for a full brown fat differentiation and white fat browning program. Mechanistically, lncBATE10 can decoy Celf1 from Pgc1α, thereby protecting Pgc1α mRNA from repression by Celf1. Together, these studies provide a comprehensive data framework to interrogate the transcriptomic changes accompanying energy homeostasis transition in adipose tissue.
Subject(s)
Adipose Tissue/metabolism , CELF1 Protein/metabolism , Energy Metabolism , Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha/metabolism , RNA, Long Noncoding/metabolism , Animals , Cell Differentiation , Cyclic AMP/metabolism , Cyclic AMP Response Element-Binding Protein/metabolism , Gene Expression Regulation , HEK293 Cells , Humans , Male , Mice, Inbred C57BL , Primary Cell Culture , Signal Transduction , TranscriptomeABSTRACT
Human antigen R (HuR) is an essential regulator of RNA metabolism, but its function in metabolism remains unclear. This study identifies HuR as a major repressor during adipogenesis. Knockdown and overexpression of HuR in primary adipocyte culture enhances and inhibits adipogenesis in vitro, respectively. Fat-specific knockout of HuR significantly enhances adipogenic gene program in adipose tissues, accompanied by a systemic glucose intolerance and insulin resistance. HuR knockout also results in depot-specific phenotypes: it can repress myogenesis program in brown fat, enhance inflammation program in epidydimal white fat and induce browning program in inguinal white fat. Mechanistically, HuR may inhibit adipogenesis by recognizing and modulating the stability of hundreds of adipocyte transcripts including Insig1, a negative regulator during adipogenesis. Taken together, our work establishes HuR as an important posttranscriptional regulator of adipogenesis and provides insights into how RNA processing contributes to adipocyte development.
Subject(s)
Adipogenesis/genetics , Adipogenesis/physiology , ELAV-Like Protein 1/metabolism , RNA-Binding Proteins/genetics , RNA-Binding Proteins/metabolism , Adipose Tissue/pathology , Adipose Tissue, Brown/metabolism , Adipose Tissue, White/metabolism , Animals , ELAV-Like Protein 1/genetics , Gene Expression Regulation , Gene Knockout Techniques , Glucose Intolerance/metabolism , Humans , Inflammation , Insulin Resistance , Intracellular Signaling Peptides and Proteins , Male , Membrane Proteins , Mice, Inbred C57BL , Mice, KnockoutABSTRACT
Long noncoding RNA(lncRNA)s are new regulators governing the metabolism in adipose tissue. In this study, we aimed to understand how lncRNAs respond to insulin signalling and explore whether lncRNAs have a functional role in insulin signalling pathway. We treated primary adipocyte cultures with insulin and collected RNA for RNA-sequencing to profile the non-coding transcriptome changes, through which we identified a top Adipose Specific Insulin Responsive LncRNA (LncASIR). To determine its biological function, we knocked down LncASIR using dcas9-KRAB, followed by RNA-seq to examine the effect on insulin-induced gene expression program. We identified a set of lncRNAs regulated by insulin signalling pathway. LncASIR is transcribed from a super enhancer region and responds robustly to insulin treatment. Silencing LncASIR resulted in an impaired global insulin-responsive gene program. LncASIR is a novel and integral component in the insulin signalling pathway in adipocytes.