Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou 221004, China.
Jiangsu Key Laboratory of Drug Screening, China Pharmaceutical University, Nanjing 210009, China.
Metabolism. 2020 Jul;108:154258. doi: 10.1016/j.metabol.2020.154258. Epub 2020 May 3.
Tubulointerstitial fibrosis, which is closely related to functional injury of the kidney, can be observed in advanced stages of diabetic nephropathy (DN). Mammalian serine/threonine-protein kinase 4 (MST1), a core component of the Hippo pathway that is involved in cellular proliferation and differentiation, plays a crucial role in the pathogenesis of multiple metabolic diseases, kidney diseases and cancer.
In type 1 and type 2 diabetic animals, as well as in human proximal tubular epithelial cells (HK-2), activation of MST1 was analyzed by immunohistochemistry and western blotting. In db/db mice, MST1 protein was knocked down or overexpressed by shRNA, and renal function, fibrosis, and downstream signaling were then investigated. RNA silencing and overexpression were performed by using an MST1 or YAP knockdown/expression lentivirus to investigate the regulation of MST1-mediated YAP/TEAD signaling pathways in the fibrosis process in HK-2 cells. Luciferase and coimmunoprecipitation (co-IP) assays were used to identify whether YAP directly regulated TEAD activation by forming a YAP-TEAD heterodimer, which ultimately leads to tubulointerstitial fibrosis.
MST1 activation was significantly decreased in type 1 and type 2 diabetic nephropathy. Notably, the downregulation of MST1 activation was also observed in HK-2 cells in a glucose- and time-dependent manner. In vivo, downregulation of MST1 was sufficient to promote renal dysfunction and fibrosis in db/m mice, whereas overexpression of MST1 ameliorated diabetic nephropathy-induced renal fibrosis. Further mechanistic study demonstrated that activated YAP induced by MST1 inhibition directly upregulated TEAD activation by binding to TEAD and forming a YAP-TEAD heterodimer, resulting in the promotion of epithelial-mesenchymal transition (EMT) and fibrosis in renal tubular epithelial.
MST1 activation represents a potential therapeutic strategy to treat or prevent the progression of diabetic nephropathy-induced renal fibrosis.
肾小管间质纤维化与肾脏功能损伤密切相关，可在糖尿病肾病（DN）的晚期观察到。哺乳动物丝氨酸/苏氨酸蛋白激酶 4（MST1）是 Hippo 通路的核心组成部分，参与细胞增殖和分化，在多种代谢性疾病、肾脏疾病和癌症的发病机制中发挥关键作用。
通过免疫组织化学和蛋白质印迹分析 1 型和 2 型糖尿病动物以及人近端肾小管上皮细胞（HK-2）中 MST1 的激活情况。在 db/db 小鼠中，通过 shRNA 敲低或过表达 MST1，然后研究肾脏功能、纤维化和下游信号通路。使用 MST1 或 YAP 敲低/表达慢病毒进行 RNA 沉默和过表达，以研究 MST1 介导的 YAP/TEAD 信号通路在 HK-2 细胞纤维化过程中的调节作用。荧光素酶和免疫共沉淀（co-IP）测定用于确定 YAP 是否通过形成 YAP-TEAD 异二聚体直接调节 TEAD 激活，从而导致肾小管间质纤维化。
MST1 激活在 1 型和 2 型糖尿病肾病中显著降低。值得注意的是，在葡萄糖和时间依赖性方式下，HK-2 细胞中 MST1 激活的下调也观察到。在体内，MST1 的下调足以促进 db/m 小鼠的肾功能障碍和纤维化，而过表达 MST1 则改善了糖尿病肾病引起的肾纤维化。进一步的机制研究表明，MST1 抑制诱导的激活 YAP 通过与 TEAD 结合并形成 YAP-TEAD 异二聚体直接上调 TEAD 激活，导致上皮-间充质转化（EMT）和肾小管上皮细胞纤维化。
MST1 的激活代表了一种潜在的治疗策略，可用于治疗或预防糖尿病肾病引起的肾脏纤维化进展。
