Wang Bin, Ding Wei, Zhang Minmin, Li Hongmei, Gu Yong
Division of Nephrology, Huashan Hospital and Institute of Nephrology, Fudan University, Shanghai, China.
Cell Physiol Biochem. 2015;35(1):116-25. doi: 10.1159/000369680. Epub 2015 Jan 2.
BACKGROUND/AIM: Aldosterone (Aldo), a mediator of kidney fibrosis, is implicated in the pathogenesis of chronic kidney diseases (CKD). The aim of this study was to evaluate the regulatory role of rapamycin (Rap) in Aldo-induced tubulointerstitial inflammation and fibrosis.
Uninephrectomized, Sprague-Dawley rats were given 1% NaCl (salt) to drink and were randomized to receive treatment for 28 days as follows: vehicle infusion (control), 0.75 μg/h Aldo subcutaneous infusion, or Aldo infusion plus 1 mg/kg/day of Rap by intraperitoneal injection. The effect of Rap on Aldo-induced fibrosis and renal inflammation was investigated using Masson's technique, immunohistochemistry, and western blotting. The effects of Rap on the Aldo-induced epithelial-mesenchymal transition (EMT) process and on TNF-α mRNA expression and secretion in cultured HK-2 cells were investigated by immunofluorescent staining, western blot, qRT-PCR and ELISA.
An in vivo study indicated that signaling by the mammalian target of Rap (mTOR) was activated in rats in the Aldo group compared to controls, as indicated by up-regulated expression of p-mTOR and p-S6K. In addition, the inflammatory response increased, as evidenced by increases in inflammatory markers (MCP-1, ICAM-1, F4/80), and the accumulation of extracellular matrix (ECM), as indicated by increased collagen I and fibronectin expression and pro-fibrogenic gene (PAI-1 and TGF-β1) expression. These changes were attenuated by Rap treatment. An in vitro study showed that Rap significantly suppressed the Aldo-induced EMT process and TNF-α mRNA expression and secretion in cultured HK-2 cells.
Rap can ameliorate tubulointerstitial inflammation and fibrosis by blocking mTOR signaling. Tubular cells may be a major cell type involved in this physiologic process.
背景/目的：醛固酮（Aldo）作为肾纤维化的介质，参与慢性肾脏病（CKD）的发病机制。本研究旨在评估雷帕霉素（Rap）对Aldo诱导的肾小管间质炎症和纤维化的调节作用。
切除一侧肾脏的Sprague-Dawley大鼠饮用1%氯化钠（盐）溶液，并随机分组接受如下治疗28天：静脉输注溶媒（对照）、0.75μg/h皮下输注Aldo，或皮下输注Aldo并腹腔注射1mg/kg/天的Rap。采用Masson染色、免疫组化和蛋白质印迹法研究Rap对Aldo诱导的纤维化和肾脏炎症的影响。通过免疫荧光染色、蛋白质印迹、qRT-PCR和ELISA研究Rap对Aldo诱导的上皮-间质转化（EMT）过程以及对培养的HK-2细胞中TNF-α mRNA表达和分泌的影响。
体内研究表明，与对照组相比，Aldo组大鼠中雷帕霉素作用靶点（mTOR）信号被激活，表现为p-mTOR和p-S6K表达上调。此外，炎症反应增强，炎症标志物（MCP-1、ICAM-1、F4/80）增加证明了这一点，细胞外基质（ECM）积聚，表现为I型胶原和纤连蛋白表达增加以及促纤维化基因（PAI-1和TGF-β1）表达增加。Rap治疗可减轻这些变化。体外研究表明，Rap可显著抑制培养的HK-细胞中Aldo诱导的EMT过程以及TNF-α mRNA表达和分泌。
Rap可通过阻断mTOR信号改善肾小管间质炎症和纤维化。肾小管细胞可能是参与这一生理过程的主要细胞类型。
