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: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: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:Analysis of RNA immunoprecipitation of HuR, a RNA binding protein (RBP), in breast cancer cell lines. This approach, utilizing RNA immunoprecipitation hybridized to microarray (RIP-Chip), provides global identification of putative endogenous mRNA targets of different RBPs. HuR is an RBP that binds to the AU-rich (ARE) regions of labile mRNAs, such as proto-oncogenes, facilitating their translation into protein. HuR has been shown to play a role in cancer progression and elevated levels of cytoplasmic HuR directly correlate with increased invasiveness and poor prognosis for many cancers, including those of the breast. We used HuR RIP-Chip as a comprehensive and systematic method to survey breast cancer target genes in both MCF-7 (estrogen receptor positive, ER+) and MDA-MB-231 (estrogen receptor negative, ER-) breast cancer cell lines. We identified unique subsets of HuR associated mRNAs found individually or in both cell types. Two novel HuR targets, CD-9 and CALM-2, were identified and validated by quantitative RT-PCR and biotin pulldown analysis. Our findings reveal that the differential regulation of these two cancer-related genes by HuR was contingent upon the cellular environment. RNA immunoprecipitation of the HuR RNA binding protein by 3A2 antibody and IgG (control) from two human breast cancer cell lines, MCF-7 and MDA-MB-231 .
Project description:The RNA decay pathway plays key regulatory roles in cell identities and differentiation processes. Although adipogenesis is transcriptionally and epigenetically regulated and has been thoroughly investigated, how RNA metabolism that contributes to the stability of phenotype-shaping transcriptomes participates in differentiation remains elusive. In this study, we investigated Ddx6, an essential component of processing bodies (PBs) that executes RNA decay and translational repression in the cytoplasm and participates in the cellular transition of reprogramming. Upon adipogenic induction, Ddx6 dynamically accumulated to form PBs with a binding partner, 4E-T, at the early phase prior to emergence of intracellular lipid droplets. In contrast, preadipocytes with Ddx6 knockout (KO) or 4E-T knockdown (KD) failed to generate PBs, resulting in significant suppression of adipogenesis. Transcription factors related to preadipocytes and negative regulators of adipogenesis that were not expressed under adipogenic stimulation were maintained in Ddx6-KO and 4E-T-KD preadipocytes under adipogenic induction. Elimination of Dlk1, a major negative regulator of adipogenesis, in 3T3L1 Ddx6-KO cells did not restore adipogenic differentiation capacity to any extent. Similar to murine cells, human primary mesenchymal stem cells, which can differentiate into adipocytes upon stimulation with adipogenic cocktails, required DDX6 to maturate into adipocytes. Therefore, RNA decay of the entire parental transcriptome, rather than removal of a strong negative regulator, could be indispensable for adipogenesis.