Department of Emergency, Zhejiang University Hospital, Hangzhou, Zhejiang, P.R. China.
Department of Nephrology, Zhejiang Provincial People's Hospital，Hangzhou, P.R. China.
Histol Histopathol. 2019 Aug;34(8):943-952. doi: 10.14670/HH-18-097. Epub 2019 Mar 6.
Diabetic kidney disease (DKD), one of the most common causes of end-stage renal disease(ESRD), remains prevalent in many populations. Podocyte loss and apoptosis play a crucial role in the progression of DKD. Tripterygium glycoside (TG), a widely used Chinese herb, exerted comprehensive protective effects on preventing DKD progression. This study was performed to assess the podocyte protective effect of tripterygium glycoside on DKD by the potential role of activation of autophagy and downregulating β-arrestin-1.
Tripterygium glycoside and small interfering RNA (siRNA) of β-arrestin-1 were added to 10% db/db mice high-glucose serum induced podocytes in vitro. Autophagic activity was evaluated by transmission electronic microscopy, immunofluorescence staining and western blot analysis. Apoptotic activity was evaluated by Annexin V-FITC/PI flow cytometric analysis. The levels of nephrin and podocin, a marker protein of podocytes, were examined using western blot analysis.
Significantly ameliorated podocyte apoptosis, increased nephrin and podocin levels and inhibited expression of β-arrestin-1 were observed after pretreatment of tripterygium glycoside in DKD mouse serum treated podocytes. Significantly higher levels of autophagic activity were also observed. Silencing β-arrestin-1 upregulated autophagic activity and ameliorated podocyte apoptosis. Silencing β-arrestin-1 in combination with tripterygium glycoside enhanced the levels of LC3-II and LC3-II/LC3-I ratios and reduced the expression of p62. Finally, we observed a notable reduction in podocyte apoptotic rate in DKD serum + siRNA-β-arrestin-1 + TG group compared to DKD serum + siRNA-β-arrestin-1 group, and upregulated protein levels of nephrin and podocin compared to treatment with siRNA-β-arrestin-1 only.
This study demonstrated that tripterygium glycoside provided protection against podocyte injury induced by high-glucose serum, and that this effect was mediated by the concomitant activation of autophagy and downregulation of β-arrestin-1.
糖尿病肾病（DKD）是终末期肾病（ESRD）最常见的病因之一，在许多人群中仍然普遍存在。足细胞丢失和凋亡在 DKD 的进展中起着至关重要的作用。雷公藤多苷（TG）是一种广泛使用的中药，对预防 DKD 进展具有全面的保护作用。本研究旨在通过激活自噬和下调β-arrestin-1 来评估雷公藤多苷对 DKD 足细胞的保护作用。
将雷公藤多苷和β-arrestin-1 的小干扰 RNA（siRNA）添加到体外 10%db/db 小鼠高糖血清诱导的足细胞中。通过透射电子显微镜、免疫荧光染色和 Western blot 分析评估自噬活性。通过 Annexin V-FITC/PI 流式细胞术分析评估凋亡活性。Western blot 分析检测足细胞标志物蛋白nephrin 和 podocin 的水平。
在 DKD 小鼠血清处理的足细胞中，雷公藤多苷预处理后观察到明显改善的足细胞凋亡、增加的 nephrin 和 podocin 水平以及抑制β-arrestin-1 的表达。还观察到自噬活性显著升高。沉默β-arrestin-1 上调自噬活性并改善足细胞凋亡。沉默β-arrestin-1 与雷公藤多苷联合使用可增加 LC3-II 和 LC3-II/LC3-I 比值，并降低 p62 的表达。最后，与 DKD 血清+siRNA-β-arrestin-1 组相比，在 DKD 血清+siRNA-β-arrestin-1+TG 组中观察到足细胞凋亡率显著降低，与仅用 siRNA-β-arrestin-1 处理相比，nephrin 和 podocin 的蛋白水平上调。
本研究表明，雷公藤多苷对高糖血清诱导的足细胞损伤具有保护作用，这种作用是通过同时激活自噬和下调β-arrestin-1 介导的。
