Hsp90, NOS3 and Cardioprotection

Hsp90、NOS3 和心脏保护

• 批准号: 7047708
• 负责人: Yang Shi
• 金额: $ 37.1万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7047708
• 关键词: aminohydrolases; cardiovascular disorder prevention; cytoprotection; disease /disorder model; enzyme activity; enzyme inhibitors; genetic strain; guanosine triphosphate; heart pharmacology; heat shock proteins; laboratory rat; molecular site; myocardial ischemia /hypoxia; nitric oxide; nitric oxide synthase; oxygen transport; phosphorylation; protein protein interaction; recombinant proteins; spontaneous hypertensive rat; tetrahydrobiopterin

DESCRIPTION (provided by applicant): Our understanding of the mechanisms mediating resistance to myocardial ischemia remains unclear. To determine mechanisms for increasing resistance to ischemia, we subjected hearts from Brown Norway (BN/Mcw) and Dahl S (SS/Mcw) rats to global ischemia. Hearts from BN/Mcw rats were more resistant to ischemia than hearts from SS/Mcw rats. Examination of cellular mechanisms revealed that although hearts from both strains exhibited the same levels of endothelial nitric oxide synthase (NOS3) and heat shock protein 90 (hsp90) expression, hearts from BN/Mcw rats generated more nitric oxide (.NO) and less superoxide anion (02.-) than hearts from SS/Mcw rats. Basic proteomic studies revealed that the shift in the balance in NO and O2.- production toward NO in the BN/Mcw hearts was due, at least in part, to altered heat shock protein 90 (hsp90) association with NOS3 and possibly, with GTP cyclohydrolase I (GTPCH-I). We observed that hsp90 association with NOS3 in BN/Mcw hearts was increased nearly 2-fold compared to association in SS/Mcw hearts; and that total biopterin, an analytical index of tetrahydrobiopterin (BH4) was increased in BN/Mcw hearts by 80%. Total biopterin concentrations in hearts from BN/Mcw rats directly correlated with a 70% increase in GTPCH-I protein levels and interestingly, a 2.2-fold increase in association of GTPCH-I with hsp90 compared to the levels in SS/Mcw hearts. These data suggest that hsp90-dependent chaperone activity may play a critical role in mechanisms governing NOS3 function that many consider to be two independent hypotheses: 1) hsp90-dependent signaling modulates NOS3 generation of .NO (coupled activity) and O2.- (uncoupled activity); and, 2) modulation of BH4 levels, which in turn, regulate coupled and uncoupled NOS3 activity. The overall objective of this proposal is to determine the cellular, molecular and enzymatic mechanisms by which hearts from BN/Mcw rats are more resistant to ischemia than hearts from SS/Mcw rats. By elucidating these pathways, findings from this proposal will provide new, fundamental insight into how hsp90 chaperone activity increases NOS3 .NO generation to increase resistance to ischemia. Observations from these studies may actually unify two hypotheses that many consider competing hypotheses in cardiovascular physiology and may also lead to the development of new strategies for treating ischemic heart disease.

描述（由申请人提供）：我们对介导心肌缺血抗性的机制的理解仍不清楚。为了确定增加对缺血的抵抗力的机制，我们将来自Brown Norway（BN/Mcw）和Dahl S（SS/Mcw）大鼠的心脏进行全脑缺血。BN/Mcw大鼠的心脏比SS/Mcw大鼠的心脏更耐缺血。对细胞机制的检查显示，尽管来自两种品系的心脏表现出相同水平的内皮型一氧化氮合酶（NOS 3）和热休克蛋白90（hsp 90）表达，但来自BN/Mcw大鼠的心脏产生更多的一氧化氮（.NO）和更少的超氧阴离子（O2.比SS/Mcw大鼠的心脏更好。基础蛋白质组学研究表明，NO和O2平衡的转变。BN/Mcw心脏中NO的产生至少部分是由于改变了热休克蛋白90（hsp 90）与NOS 3以及可能与GTP环化水解酶I（GTPCH-1）的结合。我们观察到BN/Mcw心脏中hsp 90与NOS 3的关联比SS/Mcw心脏中的关联增加近2倍;并且BN/Mcw心脏中总生物蝶呤（四氢生物蝶呤（BH 4）的分析指数）增加80%。BN/Mcw大鼠心脏中的总生物蝶呤浓度与GTPCH-I蛋白水平增加70%直接相关，有趣的是，与SS/Mcw心脏中的水平相比，GTPCH-I与hsp 90的相关性增加2.2倍。这些数据表明，hsp 90依赖性伴侣活性可能在控制NOS 3功能的机制中起关键作用，许多人认为这是两个独立的假设：1）hsp 90依赖性信号传导调节NOS 3产生NO（偶联活性）和O2。（非偶联活性）;和2）调节BH 4水平，其进而调节偶联和非偶联的NOS 3活性。本提案的总体目标是确定BN/Mcw大鼠心脏比SS/Mcw大鼠心脏更耐缺血的细胞、分子和酶机制。通过阐明这些途径，本研究的发现将为hsp 90分子伴侣活性如何增加NOS3.NO的产生以增加对缺血的抵抗力提供新的、基本的见解。这些研究的观察结果实际上可能统一了两个假设，许多人认为这两个假设在心血管生理学中相互竞争，也可能导致治疗缺血性心脏病的新策略的发展。