MiR-130a-5p prevents angiotensin II-induced podocyte apoptosis by modulating M-type phospholipase A2 receptor

Podocyte apoptosis is considered as the important element that promotes the development and progress of membranous nephropathy (MN). Unfortunately, the underlying mechanism of podocytes apoptosis in MN remains elusive. We compared the renal expressions of miR-130a-5p and M-type phospholipase A2 receptor (PLA2R) between MN patients (n = 30) and 30 controls by qRT-PCR and western blot, respectively. The podocyte damage model in vitro was established by angiotensin II (Ang II, 100 nmol/L) exposure for 24 h. Interaction between miR-130a-5p and PLA2R was determined using dual-luciferase reporter gene assay. MN mice were induced by intravenous injection of cBSA. In this study, miR-130a-5p expression was significantly decreased both in the renal biopsy specimens from MN patients and podocyte cell line AB8/13 following stimulation of Ang II. Overexpressed miR-130a-5p in AB8/13 cells significantly attenuated the Ang II induced-apoptosis in vitro. In contrast, down-regulated miR-130a-5p induced podocyte apoptosis. PLA2R was identified as the target of miR-130a-5p in AB8/13 cells. And up-regulated or down-regulated PLA2R could obviously attenuate the effect of miR-130a-5p overexpression or knockdown on the apoptosis of AB8/13 cells. Furthermore, it was also observed that overexpressed miR-130a-5p by miR-130a-5p agomir could obviously alleviate renal injury in MN mice. In conclusion, decreased miR-130a-5p was contributed to the pathological mechanism of MN through increasing PLA2R expression, which induced podocyte apoptosis.

足细胞（Podocyte）凋亡被认为是推动膜性肾病（MN）发生与进展的关键环节，但其潜在分子机制至今尚未阐明。本研究分别采用实时定量荧光聚合酶链反应（qRT-PCR）与蛋白质印迹法（western blot），对比了30例膜性肾病患者与30例健康对照者肾组织中微小RNA-130a-5p（miR-130a-5p）及M型磷脂酶A2受体（PLA2R）的表达水平。通过100 nmol/L血管紧张素II（Ang II）刺激24小时，构建体外足细胞损伤模型；采用双荧光素酶报告基因实验（dual-luciferase reporter gene assay）验证miR-130a-5p与PLA2R的靶向相互作用；通过尾静脉注射阳离子化牛血清白蛋白（cBSA）构建膜性肾病小鼠模型。实验结果显示，膜性肾病患者的肾活检标本以及经Ang II刺激后的足细胞系AB8/13中，miR-130a-5p的表达水平均显著降低。在AB8/13细胞中过表达miR-130a-5p，可显著减轻Ang II诱导的细胞凋亡；反之，下调miR-130a-5p的表达则会诱导足细胞凋亡。后续实验证实，PLA2R是miR-130a-5p在AB8/13细胞中的靶基因，上调或下调PLA2R的表达可分别逆转miR-130a-5p过表达或敲低对AB8/13细胞凋亡的调控作用。此外，通过注射miR-130a-5p激动剂（agomir）过表达miR-130a-5p，可显著缓解膜性肾病小鼠的肾损伤。综上，miR-130a-5p表达下调通过上调PLA2R的表达诱导足细胞凋亡，进而参与膜性肾病的病理进程。