Hsp90 Mediates eNOS and Vascular Function

描述（由申请人提供）：本申请的总体目标是确定热休克蛋白90（Hsp 9 O）介导内皮一氧化氮合酶（eNOS）功能以指导内皮生物学和血管生理学的机制。该实验室的最新报告表明，eNOS完全能够产生一氧化氮（.NO）和超氧阴离子（O2-）。当热休克蛋白90的构象变化被格尔德霉素（GA）阻断时，eNOS激活后产生O2-。当内皮培养物和分离的加压微血管用血管抑制素预处理时，它们似乎也通过eNOS依赖性机制产生O2，将平衡从NO转移到O2，从而损害血管舒张。这些数据表明，热休克蛋白90的相互作用直接的自由基物种是由eNOS产生。血管抑素和GA都诱导eNOS活化的改变状态，如通过eNOS上的磷酸eNOS（S1179）和与eNOS相关的Hsp 90的水平所定义的。旨在确定eNOS磷酸化状态的其他研究表明，Hsp 90与eNOS的相互作用可能保护或促进eNOS上另一位点的丝氨酸磷酸化。由于eNOS上磷酸丝氨酸的存在与该位点附近的O2负相关，因此可能通过指导自由基物质的产生来影响eNOS的功能。Hsp 90与eNOS相互作用的信号转导机制尚不清楚。由于内皮中NO和O2的平衡介导许多功能，内皮细胞增殖和血管舒张，因此了解血管抑素和GA如何改变控制eNOS功能的信号通路对于了解控制血管生成以发育新的颈动脉血管和增加血管舒张以预防缺血性心脏病的机制至关重要。这些研究结果可能会对动脉粥样硬化、高血压和糖尿病等血管疾病的发病机制提供新的认识

DESCRIPTION (provided by the applicant): The overall goal of this application is to determine the mechanisms by which heat shock protein 90 (Hsp9O) mediates endothelial nitric oxide synthase (eNOS) function to direct endothelial biology and vascular physiology. Recent reports from this laboratory demonstrate that eNOS is fully capable of generating both nitric oxide (.NO) and superoxide anion (O2-). When conformational changes in Hsp9O are blocked with geldanamycin (GA) eNOS generates O2- upon activation. When endothelial cultures and isolated pressurized microvessels are pre-treated with angiostatin they also appear to generate O2 about by an eNOS-dependent mechanism to shift the balance from .NO towards O2 about which impairs vasodilation. These data suggest that Hsp90 interactions direct which radical species is generated by eNOS. Both angiostatin and GA induce altered states of eNOS activation as defined by the levels of phospho-eNOS (S1179) on eNOS and Hsp90 associated with eNOS. Additional studies aimed at determining the phosphorylation state of eNOS suggest that Hsp90 interactions with eNOS may protect or promote serine phosphorylation at another site on eNOS. As the presence of phosphoserine on eNOS inversely correlates with O2 about this site may influence the function of eNOS by directing radical species generation. The signal transduction mechanisms governing Hsp90 interactions with eNOS with respect to O2 about generation remain unknown. As the balance of .NO and O2 about in the endothelium mediate many functions, endothelial proliferation and vasodilation, understanding how angiostatin and GA alter signaling pathways governing eNOS function is central to understanding the mechanisms governing angiogenesis for developing new collatoral vessels and increasing vasodilation to prevent ischemic heart disease. Findings from these studies will probably be relevant to and provide new understanding of mechanisms mediating vascular disease related to atherogenesis, hypertension and diabetes