Wang Xiaolei, Gao Yanbin, Tian Nianxiu, Zou Dawei, Shi Yimin, Zhang Nan
Department of Endocrinology, School of Traditional Chinese Medicine, Capital Medical University, Beijing, China,
Department of Endocrinology, Beijing Key Laboratory of Traditional Chinese Medicine Collateral Disease Theory Research, Beijing, China,
Drug Des Devel Ther. 2018 Aug 6;12:2431-2442. doi: 10.2147/DDDT.S170840. eCollection 2018.
Podocyte dedifferentiation and mesangial cell (MC) activation play an important role in many glomerular diseases associated with fibrosis. MicroRNA-21 (miR-21) is closely linked to renal fibrosis, but it is unknown whether and how miR-21 promotes podocyte dedifferentiation and MC activation and whether astragaloside IV (AS-IV) improves renal function and fibrosis through the regulation of miR-21.
Cultured MCs, primary mouse podocytes, and diabetic KK-Ay mice were treated with AS-IV. Cell transfection, Western blot, real-time PCR, immunofluorescence assay, immunohistochemical assay, and electronic microscopy were used to detect the markers of podocyte dedifferentiation and MC activation and to observe the renal morphology.
Our data showed that miR-21 expression was increased and that AS-IV decreased miR-21 levels in cells, serum, and kidney. Overexpressed miR-21 promoted podocyte dedifferentiation and MC activation, and treatment with AS-IV reversed this effect. Furthermore, the overexpression of miR-21 activated the β-catenin pathway and the transforming growth factor (TGF)-β1/Smads pathway in the process of podocyte dedifferentiation and MC activation, which was abolished by AS-IV treatment. In addition, both the Wnt/β-catenin pathway inhibitor XAV-939 and the TGF-β1/Smads pathway inhibitor SB431542 reversed the effect of AS-IV. Furthermore, AS-IV improved renal function and fibrosis in diabetic KK-Ay mice.
Our results indicated that AS-IV ameliorates renal function and renal fibrosis by inhibiting miR-21 overexpression-induced podocyte dedifferentiation and MC activation in diabetic kidney disease. These findings pave way for future studies investigating AS-IV as a potential therapeutic agent in the management of glomerular diseases.
足细胞去分化和系膜细胞（MC）活化在许多与纤维化相关的肾小球疾病中起重要作用。微小RNA-21（miR-21）与肾纤维化密切相关，但miR-21是否以及如何促进足细胞去分化和MC活化，以及黄芪甲苷IV（AS-IV）是否通过调节miR-21改善肾功能和纤维化尚不清楚。
用AS-IV处理培养的MCs、原代小鼠足细胞和糖尿病KK-Ay小鼠。采用细胞转染、蛋白质免疫印迹、实时聚合酶链反应、免疫荧光分析、免疫组织化学分析和电子显微镜检测足细胞去分化和MC活化的标志物，并观察肾脏形态。
我们的数据显示，miR-21表达增加，而AS-IV降低细胞、血清和肾脏中的miR-21水平。过表达miR-21促进足细胞去分化和MC活化，而AS-IV处理可逆转这种作用。此外，miR-21的过表达在足细胞去分化和MC活化过程中激活了β-连环蛋白通路和转化生长因子（TGF）-β1/Smads通路，而AS-IV处理可消除这种激活。此外，Wnt/β-连环蛋白通路抑制剂XAV-939和TGF-β1/Smads通路抑制剂SB431542均逆转了AS-IV的作用。此外，AS-IV改善了糖尿病KK-Ay小鼠的肾功能和纤维化。
我们的结果表明，AS-IV通过抑制miR-21过表达诱导的糖尿病肾病足细胞去分化和MC活化来改善肾功能和肾纤维化。这些发现为未来研究AS-IV作为治疗肾小球疾病的潜在治疗药物铺平了道路。
