Li Jinhua, Qu Xinli, Bertram John F
Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria 3800, Australia.
Am J Pathol. 2009 Oct;175(4):1380-8. doi: 10.2353/ajpath.2009.090096. Epub 2009 Sep 3.
Diabetic nephropathy is the leading cause of chronic renal failure. Myofibroblasts play a major role in the synthesis and secretion of extracellular matrix in diabetic renal fibrosis. Increasing evidence suggests that endothelial cells may undergo endothelial-myofibroblast transition under physiological and pathophysiological circumstances. Therefore, this study investigates whether endothelial-myofibroblast transition occurs and contributes to the development of diabetic renal interstitial fibrosis. Diabetes was induced by administration of streptozotocin to Tie2-Cre;LoxP-EGFP mice, an endothelial lineage-traceable mouse line generated by crossbreeding B6.Cg-Tg(Tek-cre)12F1v/J mice with B6.Cg-Tg(ACTB-Bgeo/GFP)21Lbe/J mice. The endothelial-myofibroblast transition was also studied in MMECs (a mouse pancreatic microvascular endothelial cell line) and primary cultures of CD31+/EYFP- (enhanced yellow fluorescent protein) endothelial cells isolated from adult normal alpha-smooth muscle actin promoter-driven-EYFP (alpha-SMA/EYFP) mouse kidneys. Confocal microscopy demonstrated that 10.4 +/- 4.2 and 23.5 +/- 7.4% of renal interstitial myofibroblasts (alpha-SMA+) in 1- and 6-month streptozotocin-induced diabetic kidneys were of endothelial origin (EGFP+/alpha-SMA+ cells), compared with just 0.2 +/- 0.1% of myofibroblasts in vehicle-treated Tie2-Cre;LoxP-EGFP mice (P < 0.01). Confocal microscopy and real-time PCR showed that transforming growth factor (TGF)-beta1 induced de novo expression of alpha-SMA and loss of expression of VE-cadherin and CD31 in MMECs and primary cultures of renal endothelial cells in a time- and dose-dependent fashion. These findings demonstrate that the endothelial-myofibroblast transition occurs and contributes to the early development and progression of diabetic renal interstitial fibrosis and suggest that the endothelial-myofibroblast transition may be a therapeutic target.
糖尿病肾病是慢性肾衰竭的主要原因。肌成纤维细胞在糖尿病肾纤维化过程中细胞外基质的合成与分泌中起主要作用。越来越多的证据表明，在生理和病理生理情况下，内皮细胞可能会发生内皮-肌成纤维细胞转变。因此，本研究探讨内皮-肌成纤维细胞转变是否发生，并是否促进糖尿病肾间质纤维化的发展。通过向Tie2-Cre;LoxP-EGFP小鼠注射链脲佐菌素诱导糖尿病，Tie2-Cre;LoxP-EGFP小鼠是通过将B6.Cg-Tg(Tek-cre)12F1v/J小鼠与B6.Cg-Tg(ACTB-Bgeo/GFP)21Lbe/J小鼠杂交产生的一种可追踪内皮细胞谱系的小鼠品系。还在MMECs（一种小鼠胰腺微血管内皮细胞系）以及从成年正常α-平滑肌肌动蛋白启动子驱动的-EYFP（α-SMA/EYFP）小鼠肾脏分离的CD31+/EYFP-（增强型黄色荧光蛋白）内皮细胞原代培养物中研究了内皮-肌成纤维细胞转变。共聚焦显微镜检查显示，在1个月和6个月链脲佐菌素诱导的糖尿病肾脏中，分别有10.4±4.2%和23.5±7.4%的肾间质肌成纤维细胞（α-SMA+）来源于内皮细胞（EGFP+/α-SMA+细胞），而在给予赋形剂处理的Tie2-Cre;LoxP-EGFP小鼠中，这一比例仅为0.2±0.1%（P<0.01）。共聚焦显微镜检查和实时PCR显示，转化生长因子（TGF）-β1以时间和剂量依赖性方式诱导MMECs和肾内皮细胞原代培养物中α-SMA的从头表达以及VE-钙黏蛋白和CD31表达的丧失。这些发现表明，内皮-肌成纤维细胞转变发生并促进糖尿病肾间质纤维化的早期发展和进展，提示内皮-肌成纤维细胞转变可能是一个治疗靶点。
