Lian Huan, Cheng Yi, Wu Xiaoyan
Department of Nephrology, Wuhan University, Zhongnan Hospital, No.169, Donghu Road, Wuchang District, Wuhan 430070, Hubei Province, PR China.
Department of Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei Province, PR China.
Biochem Biophys Res Commun. 2017 May 27;487(2):201-208. doi: 10.1016/j.bbrc.2017.04.021. Epub 2017 Apr 6.
Diabetic nephropathy (DN) is one of the most common microvascular complication of diabetes mellitus (DM) as well as the main reason resulting in chronic renal failure. Transmembrane protein 16A (TMEM16A) plays an important role in multiple physiological actions. Here we found that it was up-regulated in high-fat diet (HFD)/streptozotocin (STZ)-induced diabetic mice. Moreover, reverse transcription-polymerase chain reaction (RT-PCR) amplification, Western blot detection, Periodic Acid Schiff (PAS) staining and immunohistochemical analysis confirmed that TMEM16A deficiency alleviated renal injury in diabetic mice and TMEM16A knockout diabetic mice were protected from the HFD-induced reduction in Nephrin expression. To understand further the molecular mechanism of its function, podocytes treated with high glucose (HG, 30 mmol/L glucose) in vitro was chosen as a model to study its signal transduction pathway. Nephrin expression level in siRNA-TMEM16A group was significantly higher than that of the HG group (also called Model group). Flow cytometric analysis revealed that podocyte apoptosis in siRNA-TMEM16A group was significantly lower than that of the Model group. RT-PCR and Western blot exhibited that apoptosis-related genes including apoptosis-inducing factor (AIF) and cystinylaspartate specific protease-3/-9 (caspase-3/-9) were dramatically down regulated in siRNA-TMEM16A group, compared with Model group. Phosphorylation levels of P38 and JNK in siRNA-TMEM16A group were lower than that of the Model group. Thus, TMEM16A is one of the critical components of a signal transduction pathway that links renal injury to podocyte apoptosis in DN.
糖尿病肾病（DN）是糖尿病（DM）最常见的微血管并发症之一，也是导致慢性肾衰竭的主要原因。跨膜蛋白16A（TMEM16A）在多种生理活动中发挥重要作用。在此我们发现，在高脂饮食（HFD）/链脲佐菌素（STZ）诱导的糖尿病小鼠中其表达上调。此外，逆转录-聚合酶链反应（RT-PCR）扩增、蛋白质免疫印迹检测、过碘酸希夫（PAS）染色及免疫组化分析证实，TMEM16A缺乏可减轻糖尿病小鼠的肾损伤，且TMEM16A基因敲除的糖尿病小鼠可免受HFD诱导的Nephrin表达降低的影响。为进一步了解其功能的分子机制，选择体外高糖（HG，30 mmol/L葡萄糖）处理的足细胞作为模型来研究其信号转导通路。siRNA-TMEM16A组中Nephrin表达水平显著高于HG组（又称模型组）。流式细胞术分析显示，siRNA-TMEM16A组足细胞凋亡显著低于模型组。RT-PCR和蛋白质免疫印迹显示，与模型组相比，siRNA-TMEM16A组中包括凋亡诱导因子（AIF）和胱天冬酶-3/-9（caspase-3/-9）在内的凋亡相关基因显著下调。siRNA-TMEM16A组中P38和JNK的磷酸化水平低于模型组。因此，TMEM16A是将DN中的肾损伤与足细胞凋亡联系起来的信号转导通路的关键组成部分之一。
