Angiotensin II induces human TGF-β1 promoter activation:: similarity to hyperglycaemia
Angiotensin II induces human TGF-β1 promoter activation:: similarity to hyperglycaemia
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DOI：
10.1007/s00125-002-0843-4
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发表时间：
2002-06-01
期刊：
影响因子：
8.2
通讯作者：
Schleicher, ED
中科院分区：
文献类型：
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作者：
Weigert, C;Brodbeck, K;Schleicher, ED
目的/假说。肾脏肾素-血管紧张素系统的激活与糖尿病肾病的发病机制有关。鉴于以往的体外研究证实了血管紧张素II （ang II）介导的促性腺转化生长因子β 1 （TGF）的上调，我们研究了ang II诱导TGF- β 1基因激活的分子机制。用100nmol /l含或不含PKC和p38 MAPK抑制剂的ang II刺激系膜细胞，通过启动子报告子测定tgf - β 1启动子活性。ang II对核蛋白与调节AP-1位点B结合的影响，先前被证明介导tgf - β 1启动子的高糖反应，通过电泳迁移转移试验研究。Ang II使tgf - β 1启动子片段-453/+11的活性提高了约1.6倍。两个AP-1结合位点的突变或PKC-和p38 mapk依赖通路的抑制完全阻断了angii刺激的活性。此外，ang II激活了核蛋白与tgf - β 1启动子AP-1 box B的结合。这些影响与先前观察到的高葡萄糖相似。与angii和高糖共孵育对TGF-1启动子活性、蛋白与AP-1 box B的结合或p38 mapk的激活没有加性影响。研究结果表明，ang II和高血糖通过相同的PKC-和p38 mapk依赖途径，通过相同的tgf - β 1启动子的调控元件刺激tgf - β 1基因激活。我们的数据也可能与高血压引起的肾小球硬化有关。
Aims/hypothesis. Activation of the renal renin-angiotensin system has been implicated in the pathogenesis of diabetic nephropathy. Because previous in vitro studies demonstrated the angiotensin II (ang II)-mediated up-regulation of the prosclerotic transforming growth factor beta1 (TGF) we studied the molecular mechanism of ang II-induced TGF-beta1 gene activation.Methods. Mesangial cells were stimulated with 100 nmol/l ang II with or without inhibitors of protein kinase C (PKC) and p38 MAPK and the TGF-beta1 promoter activity was determined by promoter-reporter assays. The effect of ang II on the binding of nuclear proteins to the regulatory AP-1 site B, previously shown to mediate the high glucose-response of the TGF-beta1 promoter, was studied by electrophoretic mobility shift assays.Results. Ang II enhanced the activity of the TGF-beta1 promoter fragment -453/+11 approximately 1.6-fold. Mutation of each of two AP-1 binding sites or inhibition of the PKC- and p38 MAPK-dependent pathways blocked the ang II-stimulated activity completely. Furthermore, ang II activated the binding of nuclear proteins to the AP-1 box B of the TGF-beta1 promoter. These effects were similar to those previously observed with high glucose. Co-incubation with ang II and high glucose had no additive effect on TGF-1 promoter activity, protein binding to the AP-1 box B or activation of p38 MAPK.Conclusion/interpretation. The findings indicate that ang II and hyperglycaemia stimulate the TGF-beta1 gene activation through the same PKC- and p38 MAPK-dependent pathways by the same regulatory elements of the TGF-beta1 promoter. Our data could also be relevant for e.g. hypertension-induced glomerulosclerosis.