转染Smad 7基因的大鼠肾系膜细胞基质金属蛋白酶2及其组织抑制因子2表达的改变

Changes of matrix metalloproteinase-2 and tissue inhibitor of metalloproteinase-2 expressions on cultured rat mesangial cells transfected with Smad 7 vector

目的 通过对大鼠肾小球系膜细胞 (mesangialcell,MsC)转染Smad 7基因 ,观察转染阳性细胞克隆基质金属蛋白酶 2 (MMP 2 )及其组织抑制因子 2 (TIMP 2 )表达的改变 ,以进一步阐明Smad7阻断肾组织纤维化过程的作用机制。方法 经脂质体介导将含有Smad 7重组表达质粒转染大鼠MsC ,用G4 18筛选及Western印迹分析、逆转录 聚合酶链反应 (RT PCR)法鉴定 ;又分别采用Western印迹分析、酶谱分析法和RT PCR法 ,检测转染阳性细胞克隆MMP 2和TIMP 2表达改变。结果 成功建立高表达Smad 7的阳性MsC克隆 (S 2 2 ,S 2 6 ) ,并证实其MMP 2蛋白分泌和酶活性均明显升高 ,而TIMP 2mRNA及其蛋白的表达则被明显抑制。阳性MsC克隆S 2 2 ,S 2 6细胞分泌MMP 2比对照组高约 3 8倍 (P <0 0 1) ;S 2 2与S 2 6细胞TIMP 2蛋白表达约为对照组 4 8% (P <0 0 5 )。结论 Smad 7可能通过增强肾组织内MMP 2酶活性和抑制TIMP 2的生成而起到减轻肾组织纤维化进展的作用。

Objective To investigate matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-2 (TIMP-2) expressions in the cultured rat mesangial cells (MsC) transfected with Smad 7 vector and to elucidate the mechanism of Smad 7 in blocking tissue fibrosis. Methods Lipofectin method was used to transfect Smad 7 vector into MsC. Western blot and RT-PCR analyses were then used to detect Smad 7 protein and mRNA expression levels. The expressions of MMP-2 and TIMP-2 were determined by Western blot, RT-PCR and zymography assay. Results Two MsC clones (S-22,S-26) with Smad 7 overexpression were successfully established. The two clones showed an increased expression of MMP-2 protein and enhanced enzyme activity. The expressions of TIMP-2 protein and mRNA however were suppressed. Conclusions It is possible that Smad 7 can alleviate the development of tissue fibrosis by upregulating the expression of MMP-2 and downregulating the expression of TIMP-2 in mesangial cells.