NITRIC OXIDE PRODUCTION BY ANG II IN ENDOTHELIUM

描述（来自申请书的逐字记录）：长期目标是 在生物化学和细胞水平上识别信号转导， 将血管紧张素II（Ang II）与一氧化氮的产生联系起来的途径 (NO)是一种有效的血管扩张剂。Ang II的这种效果在 与其在心血管系统中众所周知的作用形成鲜明对比， 血管收缩剂潜在的假设是， 血管紧张素II的矛盾作用反映了与AT 1和AT 2偶联的信号传导事件。 AT 2受体，血管紧张素II的血管舒张作用是 由AT 2受体通过目前未鉴定的信号传导途径介导。 这是因为新的发现，血管紧张素II刺激NO的产生， 肺内皮细胞，通过增加内皮一氧化氮的表达 一氧化氮合酶（eNOS）。初步数据表明，这是通过 AT 2受体，并支持一种机制，通过这种机制，血管紧张素II结合到一个G 蛋白偶联的AT 2受体导致酪氨酸磷酸化的增加， 最终导致eNOS蛋白表达增加。此外，委员会认为， 通过AT 1受体的信号传导似乎负调节eNOS蛋白 表情目的研究AT 1/AT 2受体的特性 内皮细胞上的亚型分布，并进一步研究 血管紧张素II刺激eNOS mRNA和蛋白表达的机制。的作用 血管紧张素Ⅱ受体亚型在介导血管紧张素Ⅱ依赖性增强血管紧张素Ⅱ受体介导的血管紧张素Ⅱ依赖性增强中的作用 将测定肺内皮中的缺氧性血管收缩。目标 第二个目的是鉴定百日咳毒素敏感的G蛋白， 与AT 2受体相连。在目标3中，酪氨酸激酶被激活， 或蛋白酪氨酸磷酸酶，其被抑制，并提供 血管紧张素II和NO的产生之间的信号联系，将被确定。 受体拮抗剂、结合研究以及mRNA和蛋白质水平分析 将用于识别受体亚型。药理学抑制剂， 反义寡核苷酸和抗体免疫中和实验将 用于研究各种信号成分（Mg II）的作用 受体、GTP结合蛋白和蛋白激酶）。这些研究可以 为一种新的假设提供了分子基础， 血管紧张素II对平滑肌细胞的生理学上重要但相反的作用 与内皮细胞相比。这些研究具有重要的医学意义 涉及血液病理变化的心脏和肺部疾病 压力

DESCRIPTION (Verbatim from the application): The long-term goals are to identify at the biochemical and cellular levels the signal transduction pathway(s) which link Angiotensin II (Ang II) to the production of nitric oxide (NO), a potent vasodilator, in endothelial cells. This effect of Ang II is in sharp contrast to its well-known role in the cardiovascular system as a potent vasoconstrictor. The underlying hypothesis is that these apparently contradictory effects of Ang II reflect signaling events coupled to the AT1 and AT2 receptors, respectively, and that the vasodilatory effects of Ang II are mediated by the AT2 receptors via currently unidentified signaling pathways. This emerges from the novel findings that Ang II stimulates NO production in pulmonary endothelial cells, via increased expression of endothelial nitric oxide synthase (eNOS). Preliminary data indicate that this is mediated via the AT2 receptor, and support a mechanism by which Ang II binding to a G protein-coupled AT2 receptor leads to an increase in tyrosine phosphorylation, which ultimately results in increased eNOS protein expression. Furthermore, signaling via the AT1 receptor appears to negatively regulate eNOS protein expression. Aim I is directed at the characterization of AT1/AT2 receptor subtype distribution on endothelial cells, and further investigation of the mechanism of Ang II-stimulated eNOS mRNA and protein expression. The role of the Ang II receptor subtypes in mediating Ang II dependent enhancement of hypoxic vasoconstriction in pulmonary endothelium will be determined. The goal of the second aim is to identify the pertussis toxin-sensitive G protein that is linked to AT2 receptor. In Aim 3 the tyrosine kinase(s) that are activated, or protein tyrosine phosphatase(s) that are inhibited, and that provide the signaling linkage between Ang II and NO production, will be identified. Receptor antagonists, binding studies, and analysis of mRNA and protein levels will be used to identify the receptor subtypes. Pharmacological inhibitors, antisense oligonucleotides and antibody immunoneutralization experiments will be used to investigate the role of various signaling components (Mg II receptors, GTP binding proteins and protein kinases). These studies could provide a molecular basis for a novel hypothesis that would rationalize the physiologically important but opposing effects of Ang II on smooth muscle cells versus endothelial cells. These studies are of significant medical importance to heart and pulmonary disease, which involve pathological changes in blood pressure.