RNA结合蛋白人抗原R在人脂肪细胞分化中的作用

Role of RNA-binding protein HuR in human adipocyte differentiation

目的通过检测RNA结合蛋白人抗原R（HuR）与脂肪细胞型脂肪酸结合蛋白（FABP4）、脂肪酸合成酶（FASN）、脂蛋白脂肪酶（LPL）在人脂肪细胞分化过程中的表达变化，并探讨其作用。方法对人脂肪源性间充质干细胞进行成脂诱导分化，油红O染色观察细胞成脂情况，分别以实时定量PCR和Western印迹检测HuR、FABP4、FASN、LPL mRNA和蛋白表达水平的变化；siRNA干扰HuR后，进一步观察细胞成脂变化和成脂相关基因的表达水平。结果人脂肪源性间充质干细胞在成脂诱导分化过程中HuR、FABP4、FASN和LPL的mRNA和蛋白质的表达水平均显著升高（均P〈0.01）。干扰HuR表达后，细胞成脂水平干扰组较对照组下降，FABP4、FASN、LPL mRNA表达水平无明显变化，而其蛋白表达水平均显著下调（均P〈0.05）。结论HuR主要通过调节FABP4、FASN和LPL蛋白水平的变化影响成脂，促进人脂肪细胞的分化。

Objective To investigate the expressions of RNA-binding protein human antigen R（HuR）, fatty acid binding protein type 4（FABP4）, fatty acid synthetase（FASN）, and lipoprotein lipase（LPL）during the differentiation of human adipocytes, and to explore their possible roles.Methods Human adipose-derived mesenchymal stem cells were induced by adipogenic differentiation, and the adipogenesis of cells was observed by oil red O staining. The expressions of HuR, FABP4, FASN, and LPL mRNA and protein were detected by real-time PCR and Western blotting. After HuR was silenced by siRNA, the change of adipogenesis for human adipose-derived mesenchymal stem cells was observed and the expressions of adipogenic genes were detected.Results The expressions of HuR, FABP4, FASN, and LPL mRNA and protein were significantly increased after human adipose-derived mesenchymal stem cells were induced to differentiate into adipocytes（all P〈0.01）. After HuR expression was down-regulated by siRNA, the adipogenic level of human adipose-derived mesenchymal stem cells was reduced, with decreased protein levels of FABP4, FASN, and LPL（all P〈0.05）, which were without changes for their mRNA levels. Conclusion HuR promotes the differentiation of human adipocytes mainly via regulating the changes of FABP4, FASN, and LPL protein levels.