胰岛素样生长因子1和胰岛素对人α1(Ⅰ)前胶原启动子活性的影响

Effect of insulin-like growth factor 1 and insulin on promoter activity of human α1(Ⅰ) procollagen gene

目的 :探讨胰岛素样生长因子 1(IGF 1)和胰岛素对人α1(Ⅰ )前胶原 (COL1A1)基因启动子的调控作用及肿瘤坏死因子α(TNFα)、干扰素γ(IFNγ)、干扰素α(IFNα)对这一作用的影响。方法 :构建含COL1A1基因启动子序列与氯霉素乙酰基转移酶 (CAT)报告基因的重组体pCOLH0 2 7与pCOLH2 5 ,它们分别含该启动子序列 2 68～ + 4 2bp( 0 2 7kb)与 2 4 83～ + 4 2bp( 2 5kb)片段。将这 2个重组体瞬时转染人皮肤成纤维细胞 ,加入IGF 1或胰岛素 ,部分细胞还加入TNFα或IFNγ或IFNα,测定CAT活性。结果 :13nmol/LIGF 1使转染后的这 2个重组体活性分别增高 3 68倍与 4 0 4倍。 2 5 μmol/L的胰岛素亦使之分别增高 3 69倍与 3 93倍。TNFα、IFNγ、IFNα能降低IGF 1与胰岛素诱导的pCOLH2 5活性。结论 :IGF 1和胰岛素能在转录水平促进COL1A1基因的表达 ,TNF α、IFNγ、IFNα能抑制IGF 1和胰岛素的这一作用。

Objective:To study the effect of insulin like growth factor 1 and insulin on the promoter activity of human α1(Ⅰ) procollagen (COL1A1) gene and the influence of tumor necrosis factor α(TNFα), interferon γ (IFNγ) and interferon α(IFNα) on the effect Methods:Two deletion constructs,pCOLH0 27 and pCOLH2 5 ,containing portions of 5' flanking region of the gene ( 268～+42 bp and 2 483～+42 bp respectively) ligated to the chloramphenicol acetyltransferase (CAT) reporter gene ,were transiently transfected into human skin fibroblasts The cells were subsequently treated with IGF 1 or insulin, and TNFα or IFNγ or IFNα The CAT activity was assessed 24 h after the cytokines added Results:The results showed that 13 nmol/L IGF 1 caused 3 68 fold and 4 04 fold increase in the CAT activity of pCOLH0 27 and pCOLH2 5 respectively and that 2 5 μmol/L insulin caused 3 69 fold and 3 93 fold increase in the activity of the two plasmids respectively TNFα,IFNγ and IFNα reduced IGF 1 or insulin induced promoter activity of pCOLH2 5 Conclusion:IGF 1 and insulin could increase the promoter activity of the human (COL1A1) gene TNFα,IFNγ and IFNα could suppress the promoter activity induced by IGF 1 and insulin