Regulation of angiotensin-induced PAI-1 expression

描述（由申请人提供）：实质性实验和临床 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（AngII）/AT 1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。举报 PI的实验室和其他研究小组已经证明，AngII是一种 纤溶酶原激活物抑制剂-1（派-1）表达的有效刺激剂， 培养的血管细胞和RAS抑制降低新生内膜派-1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通路抑制血管紧张素II诱导的派-1 表情在初步研究中，我们发现cGMP抑制AngII， 通过SAPK/JNK途径的信号传导，并已确定了38个碱基对 派-1启动子上的区域，该区域被该途径激活并被抑制 通过cGMP和MEK-1，2抑制。该区域的突变分析 显示AP-1和Sp1站点都需要支持MEKK-1 刺激.此外，派-1启动子活性被协同激活， c-Jun和Sp1的组合过表达。这些结果证明了 派-1启动子的MEKK-1/MEK 1，2激活的新机制， 这取决于相邻的Sp1和AP-1元件的协同作用。的 在这项研究中要检验的假设是，AngII/AT 1受体信号传导 通过MEKK-1/MEK，1，2/JNK途径激活派-1转录，并且这种应答 被cGMP抑制。为了验证这一假设，本提案将审查 这些MAP激酶的显性负性成分表达的影响 血管紧张素Ⅱ信号通路及其对内源性派-1 mRNA的刺激作用 表情此外，组成性活性成分的影响， 将检测这些MAP激酶途径对派-1启动子活性的影响。的 cGMP对这些反应的影响将使用新的结构化方法进行检查。 活性鸟苷酸环化酶。AT 1受体诱导的 派-1的表达将在对照组和遗传诱导组中进行研究。 糖尿病小鼠本研究将探讨AngII/AT 1通路与血管生成的关系。 增加1型糖尿病血管派-1表达。审查这个 假设，调节血管紧张素AT受体和血管紧张素II的影响， 派-1的表达将在一种新的自发性的转基因模型中进行检测。 并且在C57 B1/6小鼠（BDC2.51B6.g7g7小鼠）中发展了特异性I型糖尿病。 长期目标是确定新的目标和控制方法 血管紧张素Ⅱ对派-1表达的影响不依赖于血压。

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.