Department of Endocrinology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, 7th Floor, Tower I, 3 East Qingchun Road, Hangzhou, ZJ 571, China.
Department of Endocrinology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, 7th Floor, Tower I, 3 East Qingchun Road, Hangzhou, ZJ 571, China.
Exp Cell Res. 2020 Feb 15;387(2):111753. doi: 10.1016/j.yexcr.2019.111753. Epub 2019 Dec 12.
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).
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.
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.
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.
代谢综合征（MetS）的特征是一组医学疾病。脂肪组织功能的改变对全身代谢有重大影响，是 MetS 的关键驱动因素。在这项研究中，我们旨在探索人环状 RNA H19（hsa_circH19）在人脂肪源性干细胞（hADSCs）中的功能。
使用 MetS 患者和正常受试者的血液样本确定 hsa_circH19 的表达水平。在 hADSCs 中敲低 hsa_circH19 后，我们测量了脂肪生成基因的表达。进行油红 O、尼罗红染色测定和三酰甘油评估，以检查 hsa_circH19 在 hADSCs 分化中的作用。然后，进行 RNA 下拉和 RIP 测定以探索 hsa_circH19 的相关 RNA 结合蛋白。IF 用于确定潜在的分子调节机制。
在考虑混杂因素后，高水平的 hsa_circH19 仍然是 MetS 的独立危险因素。此外，hsa_circH19 的敲低显著增加了脂肪生成基因的表达和脂滴的形成。生物信息学分析表明，hsa_circH19 与多嘧啶 tract 结合蛋白 1（PTBP1）共享多个结合位点，其相互作用通过 circRNA 下拉和 RIP 测定得到验证。机制上，在存在 PTBP1 的情况下，hsa_circH19 的耗竭会触发固醇调节元件结合蛋白 1（SREBP1）从细胞质向细胞核的易位。
我们的实验表明，敲低 hsa_circH19 通过靶向 PTBP1 促进 hADCSs 脂肪生成分化。因此，hsa_circH19 的表达可能与 MetS 脂肪组织中的脂质代谢相关。
