Department of Pharmacy, The People's Hospital of Jiangyin, Jiangyin, Jiangsu 214400, P.R. China.
Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu 221004, P.R. China.
Int J Mol Med. 2019 Feb;43(2):709-716. doi: 10.3892/ijmm.2018.3999. Epub 2018 Nov 26.
Astragaloside IV (AST) is the major active saponin in Astragalus membranaceus and, reportedly, has a variety of pharmacological activities. However, the potential of AST to ameliorate high glucose‑mediated renal tubular epithelial‑mesenchymal transition (EMT) remains undetermined. The aim of the present research was to explore the effect and mechanism of AST in EMT of renal tubular epithelial cells, as an underlying mechanism of renal fibrosis and a vital feature involved in diabetic nephropathy. The effect of AST on the EMT of renal tubular epithelial cells (HK‑2) stimulated by high glucose was investigated and it was attempted to elucidate the potential underlying mechanism. The expression of E‑cadherin and α‑smooth muscle actin were determined by western blotting and immunofluorescence assays. The expression of the mammalian target of rapamycin complex 1 (mTORC1)/ ribosomal protein S6 kinase β‑1 (p70S6K) signaling pathway and protein levels of four transcriptional factors (snail, slug, twist and zinc finger E‑box‑binding homeobox 1) were also determined by western blotting. Additionally, extracellular matrix components, including fibronectin (FN) and collagen type IV (Col IV) were detected by ELISA. The results suggested that the EMT of HK‑2 cells and the mTORC1/p70S6K pathway were activated by high glucose. The expression of snail and twist in HK‑2 cells was elevated by high glucose. Furthermore, extracellular matrix components, FN and Col IV, were increased in HK‑2 cells cultured with high glucose. In turn, treatment with AST reduced EMT features in HK‑2 cells, inhibited mTORC1/p70S6K pathway activation, downregulated expression of snail and twist, and reduced secretion of FN and Col IV. In summary, the findings suggested that AST ameliorates high glucose‑mediated renal tubular EMT by blocking the mTORC1/p70S6K signaling pathway in HK‑2 cells.
黄芪甲苷（AST）是黄芪中的主要活性皂苷，据报道具有多种药理活性。然而，AST 改善高糖介导的肾小管上皮-间充质转化（EMT）的潜力尚未确定。本研究旨在探讨 AST 对高糖刺激的肾小管上皮细胞（HK-2）EMT 的作用及其机制，这是肾脏纤维化的潜在机制，也是糖尿病肾病的重要特征。研究了 AST 对高糖诱导的肾小管上皮细胞 EMT 的影响，并试图阐明其潜在机制。通过 Western blot 和免疫荧光法测定 E-钙黏蛋白和α-平滑肌肌动蛋白的表达。Western blot 还测定了雷帕霉素复合物 1（mTORC1）/核糖体蛋白 S6 激酶β-1（p70S6K）信号通路和四个转录因子（snail、slug、twist 和锌指 E-盒结合同源框 1）的蛋白水平。此外，通过 ELISA 检测细胞外基质成分，包括纤维连接蛋白（FN）和 IV 型胶原（Col IV）。结果表明，高糖激活了 HK-2 细胞的 EMT 和 mTORC1/p70S6K 通路。高糖可上调 HK-2 细胞中 snail 和 twist 的表达。此外，高糖培养的 HK-2 细胞中细胞外基质成分 FN 和 Col IV 增加。AST 处理可减少 HK-2 细胞 EMT 特征，抑制 mTORC1/p70S6K 通路激活，下调 snail 和 twist 的表达，并减少 FN 和 Col IV 的分泌。综上所述，AST 通过阻断 HK-2 细胞中的 mTORC1/p70S6K 信号通路改善高糖介导的肾小管 EMT。
