作　　者： ; ; ; ; ; ;

机构地区： 北京协和医院

出　　处： 《中国医学科学院学报》 2005年第3期325-331,i001,共8页

摘　　要： 目的探讨转化生长因子β1(TGFβ1)诱导人肾小管上皮细胞(HK-2)转分化过程中,血管内皮细胞生长因子(VEGF)及其受体表达的变化。方法用不同浓度的TGFβ1诱导HK-2转分化,细胞免疫化学方法检测血管平滑肌肌动蛋白(α-SMA),反转录-聚合酶链反应(RT-PCR)检测α-SMA和VEGFmRNA表达,酶联免疫分析(ELISA)检测上清中的VEGF,免疫印迹检测细胞裂解物中的VEGF及其受体。结果(1)HK-2细胞在TGFβ1(5、8ng/ml)刺激后,α-SMA免疫染色均为阳性,以8ng/ml时最强;TGFβ1呈剂量和时间依赖诱导α-SMAmRNA表达(P<0.001)。(2)TGFβ1诱导HK-2细胞转分化过程中,VEGF从基因到蛋白水平呈双相改变:0.1和1ng/mlTGFβ1刺激后VEGFmRNA和蛋白表达强度均高于对照组(P<0.001);而3、5和8ng/mlTGFβ1刺激后表达强度则低于对照组(P<0.001)。8ng/mlTGFβ1刺激较短时间(12和24h),VEGFmRNA和蛋白表达强度高于对照组(P<0.001);而刺激较长时间(36、48和72h),mRNA和蛋白表达强度均低于对照组(P<0.001)。(3)TGFβ1诱导HK-2细胞转分化过程中,以浓度和时间依赖性方式诱导VEGF受体表达增强(P<0.001)。结论TGFβ1诱导HK-2细胞转分化过程中,VEGF受体表达增强,而VEGF表达出现双相变化,高浓度的TGFβ1刺激可引起VEGF表达下调。 Objective To examine the expression of vascular endothelial growth factor(VEGF)and its receptors(VEGFR1, VEGFR2)in transdifferentiated human proximal tubular epithelial(HK-2)cell induced by transforming growth factorβ1(TGFβ1). Methods The transdifferentiation of HK-2 cells was detected by evaluation of expression of α-SMA by cytoimmunochemistry and RT-PCR. The VEGF mRNA was evaluated with RT-PCR. The secreted VEGF in the culture media was measured with ELISA. The cellular VEGF, VEGFR1, and VEGFR2 were measured with Western blot. Results The immunostain of α-SMA were positive in HK-2 cell induced by TGFβ1 at the concentration of 5 and 8 ng/ml for 72 h. The expression of α-SMA mRNA was induced by TGFβ1 in concentration- and time- dependent manners. The expressions of mRNA and protein of VEGF were upregulated by TGFβ1 at the concentration of 0.1 and 1 ng/ml for 72 h and at the concentration of 8 ng/ml for 12 h and 24 h when compared with the control. But expressions of mRNA and protein of VEGF were downregulated by TGFβ1 at the concentration of 3, 5, and 8 ng/ml for 72 h and at the concentration of 8 ng/ml for 36, 48, and 72 h, respectively. Meanwhile, Protein levels of VEGFR1 and VEGFR2 were upregulated by TGFβ1 in concentration- and time- dependent manners. Conclusions Increased expression of VEGFR1 and VEGFR2 and two-phase change in VEGF expression occurred in the process of tubular epithelial transdifferentiation induced by TGFβ1. Reduced expression of VEGF may contribute to tubular epithelial transdifferentiation in a vicious circle.

关 键 词： 肾小管上皮细胞转分化 转化生长因子 血管内皮细胞生长因子

领　　域： [生物学]