Project description:Human antigen R (HuR) protein, a RNA binding protein (RBP), has been reported to regulate essential steps in RNA metabolism and immune response in a variety of cell types, 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 all three major adipose tissues including epidydimal, inguinal white and brown adipose tissue, accompanied with systemic glucose intolerance and insulin resistance. Conversely, transgenic overexpression of HuR in adipose tissue prevents the HFD induced obesity by repressing adipogenesis. Mechanistically, HuR may inhibit adipogenesis by recognizing and modulating the stability of hundreds of adipocyte transcripts, including the mRNA of Insig1, a negative regulator during adipogenesis. Taken together, our work establishes HuR as a novel posttranscriptional regulator of adipogenesis and provides a new insight into how RNA processing contributes to adipocyte development.
Project description:Human antigen R (HuR) protein, a RNA binding protein (RBP), has been reported to regulate essential steps in RNA metabolism and immune response in a variety of cell types, 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 all three major adipose tissues including epidydimal, inguinal white and brown adipose tissue, accompanied with systemic glucose intolerance and insulin resistance. Conversely, transgenic overexpression of HuR in adipose tissue prevents the HFD induced obesity by repressing adipogenesis. Mechanistically, HuR may inhibit adipogenesis by recognizing and modulating the stability of hundreds of adipocyte transcripts, including the mRNA of Insig1, a negative regulator during adipogenesis. Taken together, our work establishes HuR as a novel posttranscriptional regulator of adipogenesis and provides a new insight into how RNA processing contributes to adipocyte development.
Project description:Human antigen R (HuR) protein, a RNA binding protein (RBP), has been reported to regulate essential steps in RNA metabolism and immune response in a variety of cell types, 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 all three major adipose tissues including epidydimal, inguinal white and brown adipose tissue, accompanied with systemic glucose intolerance and insulin resistance. Conversely, transgenic overexpression of HuR in adipose tissue prevents the HFD induced obesity by repressing adipogenesis. Mechanistically, HuR may inhibit adipogenesis by recognizing and modulating the stability of hundreds of adipocyte transcripts, including the mRNA of Insig1, a negative regulator during adipogenesis. Taken together, our work establishes HuR as a novel posttranscriptional regulator of adipogenesis and provides a new insight into how RNA processing contributes to adipocyte development.
Project description: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.
Project description:We performed high throughput RNA sequencing at preadipocyte (D0) and differentiated adipocyte (D7) of primary brown preadipocyte and found that Kruppel-like factor 16 (KLF11) gene that was downregulated in D7 was a novel negative regulator of adipogenesis.
Project description:HuR is a regulator of mRNA turnover or translation of inflammatory genes through binding to adenylate-uridylate-rich elements (ARE) and related motifs present in the 3’untranslated region (UTR) of mRNAs. We aimed to identify HuR targets in the human airway epithelial cell line BEAS-2B challenged with TNFa plus IFNg, a strong stimulus for inflammatory epithelial responses. Ribonucleoprotein (RNP) complexes from resting and cytokine-treated cells were immunoprecipitated (IP) using anti-HuR and isotype-control antibody, and eluted mRNAs were reverse-transcribed and hybridized to an inflammatory-focused gene array. The chemokines CCL2, CCL8, CXCL1 and CXCL2 ranked highest among 27 signaling and inflammatory genes significantly enriched in the HuR RNP-IP from stimulated cells over the control IP. Among these, 20 displayed published HuR binding motifs. Association of HuR with the four endogenous chemokine mRNAs was validated by single-gene RNP-IP, and shown to be 3’UTR-dependent by biotin pull-down assay. Cytokine treatment increased mRNA stability only for CCL2 and CCL8, and transient silencing and overexpression of HuR affected only CCL2 and CCL8 expression in primary and transformed epithelial cells. Cytokine-induced CCL2 mRNA was predominantly cytoplasmic; conversely, CXCL1 mRNA remained mostly nuclear and unaffected, as CXCL2, by changes in HuR levels. Increase in cytoplasmic HuR and HuR target expression partially relied on the inhibition of AMP-dependent kinase, a negative regulator of HuR nucleocytoplasmic shuttling.