Abstract

Protection against renal fibrosis is important for the management of obstructive nephropathy. We researched the roles and possible mechanism of miR-155-5p in renal interstitial fibrosis, which may provide a potential endogenous target for renal interstitial fibrosis in obstructive nephropathy. Herein, NRK-49F cells were transfected with miR-155-5p mimic, miR-155-5p inhibitor, SIRT1 plasmid and/or SIRT1 siRNA. The unilateral ureteral obstruction (UUO) model was built with male C57 black mice and administrated with SRT1720 by tail vein injection. Levels of miR-155-5p, SIRT1 and relative proteins (TGF-β1, α-SMA, Collage I and fibronectin) in NRK-49F cells or mice kidney tissues were measured with quantitative reverse transcription polymerase chain reaction or Western blot. The target gene of miR-155-5p was analyzed through TargetScan and dual-luciferase reporter assay. Mice kidney tissue was stained with Masson trichrome. It was found that miR-155-5p overexpression promoted the expressions of fibroblast related proteins expression and inhibited the SIRT1 expression in NRK-49F cells, while miR-155-5p silencing had an opposite effect. SIRT1 can bind with miR-155-5p. MiR-155-5p inhibited the level of SIRT1. Fibroblast related proteins were up-regulated by miR-155-5p and down-regulated by SIRT1 in NRK-49F cells, while the up-regulatory effect of miR-155-5p was reversed by SIRT1. MiR-155-5p expression was up-regulated and SIRT1 expression was down-regulated in the kidney tissue of UUO mice. SRT1720 attenuated the fiber deposition, up-regulated SIRT1 level and down-regulated the levels of fibroblast related proteins in UUO model mice. To conclude, miR-155-5p promotes renal interstitial fibrosis in obstructive nephropathy via inhibiting SIRT1 signaling pathway.

摘要

预防肾纤维化对于阻塞性肾病的治疗很重要。我们研究了miR-155-5p在肾间质纤维化中的作用和可能的机制，这可能为阻塞性肾病肾间质纤维化提供潜在的内源性靶点。在此，用 miR-155-5p 模拟物、miR-155-5p 抑制剂、SIRT1 质粒和/或 SIRT1 siRNA 转染 NRK-49F 细胞。用雄性C57黑鼠建立单侧输尿管梗阻（UUO）模型，并通过尾静脉注射SRT1720给药。用定量逆转录聚合酶链反应或蛋白质印迹法测量 NRK-49F 细胞或小鼠肾组织中 miR-155-5p、SIRT1 和相关蛋白（TGF-β1、α-SMA、胶原蛋白 I 和纤连蛋白）的水平。通过TargetScan和双荧光素酶报告基因分析miR-155-5p的靶基因。小鼠肾组织用马松三色染色。结果发现，miR-155-5p过表达促进了NRK-49F细胞中成纤维细胞相关蛋白的表达并抑制了SIRT1的表达，而miR-155-5p沉默则具有相反的作用。SIRT1 可以与 miR-155-5p 结合。MiR-155-5p 抑制 SIRT1 的水平。在 NRK-49F 细胞中，成纤维细胞相关蛋白被 miR-155-5p 上调并被 SIRT1 下调，而 miR-155-5p 的上调作用被 SIRT1 逆转。UUO 小鼠肾脏组织中 MiR-155-5p 表达上调，SIRT1 表达下调。SRT1720 衰减纤维沉积，上调 SIRT1 水平并下调 UUO 模型小鼠中成纤维细胞相关蛋白的水平。总之，miR-155-5p 促进阻塞性肾病肾间质纤维化通过抑制 SIRT1 信号通路。