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目的 探讨转化生长因子 β1(TGFβ1)和血小板源生长因子 (PDGF)对人α1Ⅰ型胶原基因启动子活性的调控作用和氯沙坦药物干预的影响环节。方法 将不同长度的人α1I型胶原基因启动子片段与氯霉素乙酰基转移酶 (CAT)“报告基因”组成重组体pCOLH 1.5和pCOLH 2 .5 ,采用脂质体法转染至培养的大鼠肾小球系膜细胞 ,分别加入不同浓度的TGFβ1、PDGF、血管紧张素Ⅱ (AngⅡ )和氯沙坦 ,ELISA法测定CAT活性。结果 TGFβ1表现为剂量依赖性地促进pCOLH 1.5和pCOLH 2 .5的活性 ,与对照组比较差别有非常显著性意义 (P <0 .0 1)。PDGF(10～ 2 5 μg/L)未发现有明显影响 (P >0 .0 5 ) ,AngⅡ则具有促进其活性作用。氯沙坦不但能抑制两个重组体的CAT表达 ,和AngⅡ共同作用时 ,pCOLH 2 .5CAT的升高幅度明显减少 (P <0 .0 1)。结论 在肾小球系膜细胞中 ,TGFβ1具有促进人α1Ⅰ型胶原基因启动子的转录活性 ,PDGF则未发现有显著促进或抑制效应。氯沙坦能下调人α1Ⅰ型胶原基因启动子的激活 ,并可部分拮抗AngⅡ的促进作用。
Objective To investigate the effects of transforming growth factor β1 (TGFβ1) and platelet derived growth factor (PDGF) on the promoter activity of human α1-type collagen gene and the intervention of losartan. Methods Recombinant pCOLH 1.5 and pCOLH 2 .5 were amplified by PCR from human α1I collagen gene promoter fragment and chloramphenicol acetyltransferase (CAT) reporter gene with different lengths. The recombinant plasmid pCOLH 1.5 and pCOLH 2 .5 were transfected into cultured large The rat glomerular mesangial cells were treated with different concentrations of TGFβ1, PDGF, Ang Ⅱ and losartan respectively. The activity of CAT was measured by ELISA. Results TGFβ1 showed a dose-dependent increase in the activity of pCOLH 1.5 and pCOLH 2 .5, which was significantly different from the control group (P <0.01). PDGF (10 ~ 25 μg / L) did not find any significant effect (P> 0.05), while AngⅡ could promote its activity. Losartan not only inhibited the CAT expression of the two recombinants, but decreased the increase of pCOLH2.5CAT when combined with AngⅡ (P <0.01). Conclusion TGFβ1 can promote the transcriptional activity of human α1-type collagen gene promoter in mesangial cells, and no significant promoting or inhibiting effect is found on PDGF. Losartan down-regulated the activation of human α1Ⅰcollagen gene promoter and partially antagonized the promotion of AngⅡ.