Regulation of angiotensin-induced PAI-1 expression

描述(申请人提供)：大量实验和临床研究 有证据表明，肾素-血管紧张素系统(RAS)主要通过 血管紧张素II(Ang11)/AT1受体途径，发挥促动脉粥样硬化和 促血栓形成作用，即使在没有高血压的情况下也是如此。来自美国的报道 派的实验室和来自其他组织的证据表明，安吉是一个 纤溶酶原激活物抑制物-1(PAI-1)的表达 培养的血管细胞和RAS抑制减少新生内膜PAI-1的表达 在正常血压大鼠体内的血管组织中。最近，我们还 报道一氧化氮/cGMP途径抑制血管紧张素Ⅱ诱导的PAI-1 表情。在初步研究中，我们发现cGMP抑制血管紧张素转换酶II 通过SAPK/JNK通路传递信号，并确定了38个碱基对 PAI-1启动子上的区域，该区域被该途径激活并抑制 CGMP和MEK-1，2抑制。该区域的突变分析 透露AP-1和Sp1站点都需要支持Mekk-1 刺激。此外，PAI-1启动子的活性也被协同激活 C-jun和Sp1的联合过表达。这些结果证明了一个 PAI-1启动子激活Mekk-1/MEK1，2的新机制 依赖于相邻的Sp1和AP-1元件的协同作用。这个 在这项研究中要检验的假设是，血管紧张素Ⅱ/AT1受体信号 通过Mekk-1/MEK，1，2/JNK途径激活PAI-1转录和这一反应 被cGMP抑制。为了检验这一假设，该提案将检验 这些MAPK的显性负组分表达的影响 血管紧张素Ⅱ信号转导通路及其对内源性PAI-1mRNA的刺激 表情。此外，成分活性成分的影响 这些MAPK通路对PAI-1启动子活性的影响将被检测。这个 CGMP对这些反应的影响将使用新的结构性检查 活性鸟苷酸环化酶。AT1受体诱导的生理学意义 PAI-1的表达将在对照和基因诱导下进行研究 糖尿病小鼠。这项提议将检验Angii/AT1途径的假设 增加1型糖尿病患者血管PAI-1的表达。要检查这一点 血管紧张素转换酶受体的假说、调节及血管紧张素转换酶II的作用 PAI-1的表达将在一种新的自发性心脏病转基因模型中进行检测 特异性I型糖尿病发生在C57B1/6小鼠(BDC2.51B6.g7g7小鼠)中。 长期目标是确定新的目标和控制方法 Ang II对PAI-1表达的血压非依赖性影响。

DESCRIPTION (provided by applicant): Substantial experimental and clinical evidence suggests that the renin-angiotensin system (RAS), primarily via the angiotensin II (Angll)/AT1 receptor pathway, exerts pro-atherogenic and pro-thrombogenic effects, even in the absence of hypertension. Reports from the PI's laboratory, and from other groups, have demonstrated that AngII is a potent stimulator of plasminogen activator inhibitor-1(PAI-1) expression in cultured vascular cells and RAS inhibition reduces neointimal PAI-1 expression in vascular tissues in normotensive rats in vivo. Recently, we have also reported that the nitric oxide/cGMP pathway suppresses AngII-induced PAI-1 expression. In preliminary studies, we have found that cGMP inhibits AngII signaling through the SAPK/JNK pathway and have identified a 38 base pair region on the PAI-1 promoter, which is activated by this pathway and inhibited by both cGMP and MEK-1,2 inhibition. Mutational analysis of this region revealed that both AP-1 and Sp1 sites were required to support the MEKK-1 stimulation. Moreover, PAI-1 promoter activity was synergistically activated by combined over-expression of both c-Jun and Sp1. These results demonstrate a novel mechanism for MEKK-1/MEK1,2 activation of the PAI-1 promoter that is dependent on the cooperative effects of adjacent Sp1 and AP-1 elements. The hypothesis to be tested in this grant is that the AngII/ AT1 receptor signaling via MEKK-1/MEK,1,2/JNK pathways activate PAI-1 transcription and this response in suppressed by cGMP. To test this hypothesis, this proposal will examine the effects of expression of dominant negative components of these MAP kinase pathways on Ang II-signaling and its stimulation of endogenous PAI-1 mRNA expression. In addition, the effects of constitutively active components of these MAP kinase pathways on PAI-1 promoter activity will be examined. The effects of cGMP on these responses will be examined using novel constititively active guanylyl cyclases. The physiological relevance of AT1 receptor-induced PAI-1 expression will be investigated in both control and genetically induced diabetic mice. This proposal will examine the hypothesis that AngII/AT1 pathway increases vascular PAI-1 expression in type 1 diabetes. To examine this hypothesis, the regulation of angiotensin AT receptors and Ang II effects on PAI-1 expression will be examined in a novel transgenic model of spontaneous and specific type I diabetes developed in C57B1/6 mice (BDC2.51B6.g7g7 mice). The long-term objective is to identify novel targets and approaches to control the blood pressure independent effects of Ang II on PAI-1 expression.