PURPOSE The metabolic syndrome (MetS) is characterized of a cluster of medical disorders. Altered function of adipose tissue has a significant impact on whole-body metabolism and represents a key driver for MetS. In this study, we aim to explore the function of human circular RNA H19 (hsa_circH19) in human adipose-derived stem cells (hADSCs). METHODS The blood samples from MetS patients and normal subjects were used to determine the expression level of the hsa_circH19. After knock-down of hsa_circH19 in hADSCs, we measured the expression of adipogenic genes. Oil red O, Nile red staining assay and triglyceride assessment were performed to examine the role of hsa_circH19 in hADSCs differentiation. Then, RNA Pull-down and RIP assays were conducted to explore the related RNA binding protein of hsa_circH19. IF was performed to determine the potential molecular regulatory mechanism. RESULTS After accounting for confounding factors, high levels of hsa_circH19 remained an independent risk factor for MetS. Furthermore, the knockdown of hsa_circH19 significantly increased the expression of adipogenic genes and the formation of lipid droplets. Bioinformatics analyses revealed that has_circH19 shared multiple binding sites with polypyrimidine tract-binding protein 1 (PTBP1) and their interaction was validated by circRNA pull-down and RIP assays. Mechanistically, depletion of hsa_circH19 triggered translocation of sterol-regulatory element binding proteins (SREBP1) from cytoplasm to nucleus in the presence of PTBP1. CONCLUSION Our experiments suggest that knockdown of hsa_circH19 promotes hADCSs adipogenic differentiation via targeting of PTBP1. In consequence, the expression of hsa_circH19 might correlated to lipid metabolism in adipose tissue from MetS.

中文翻译：

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敲除环状RNA H19通过涉及多嘧啶束结合蛋白1的机制诱导人脂肪干细胞成脂分化。

目的代谢综合症（MetS）的特征是一系列医学疾病。脂肪组织功能的改变对全身代谢有重要影响，并且是MetS的关键驱动力。在这项研究中，我们旨在探索人类环状RNA H19（hsa_circH19）在人类脂肪干细胞（hADSCs）中的功能。方法采用MetS患者和正常人的血样测定hsa_circH19的表达水平。敲低hADSCs中的hsa_circH19后，我们测量了成脂基因的表达。进行油红O，尼罗红染色测定和甘油三酸酯评估以检查hsa_circH19在hADSCs分化中的作用。然后，进行RNA Pull-down和RIP分析以探索hsa_circH19的相关RNA结合蛋白。进行中频以确定潜在的分子调控机制。结果在考虑了混杂因素之后，高水平的hsa_circH19仍然是MetS的独立危险因素。此外，hsa_circH19的敲除显着增加了成脂基因的表达和脂质滴的形成。生物信息学分析表明，has_circH19与聚嘧啶束结合蛋白1（PTBP1）共享多个结合位点，并且通过circRNA下拉和RIP分析验证了它们的相互作用。从机制上讲，在PTBP1存在的情况下，hsa_circH19的耗竭触发了固醇调节元件结合蛋白（SREBP1）从细胞质向细胞核的易位。结论我们的实验表明，敲除hsa_circH19可通过靶向PTBP1促进hADCSs成脂分化。