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抵抗的机制的理解尚不清楚。为了确定增加缺血抵抗的机制，我们对褐挪威（BN/Mcw）和达尔S （SS/Mcw）大鼠的心脏进行了全身缺血。BN/Mcw大鼠的心脏比SS/Mcw大鼠的心脏更耐缺血。细胞机制检查显示，尽管两种菌株的心脏内皮一氧化氮合酶（NOS3）和热休克蛋白90 （hsp90）表达水平相同，但BN/Mcw大鼠的心脏比SS/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（02.-）。基础蛋白质组学研究揭示了一氧化氮和氧平衡的改变。- BN/Mcw心脏中NO的生成至少部分是由于与NOS3以及可能与GTP环水解酶I （GTPCH-I）相关的热休克蛋白90 （hsp90）的改变。我们观察到，与SS/Mcw心脏相比，BN/Mcw心脏中hsp90与NOS3的关联增加了近2倍；总生物蝶呤，四氢生物蝶呤（BH4）的分析指标在BN/Mcw心脏中增加了80%。BN/Mcw大鼠心脏中总生物terin浓度与GTPCH-I蛋白水平增加70%直接相关，有趣的是，与SS/Mcw心脏相比，GTPCH-I与hsp90的相关性增加了2.2倍。这些数据表明，hsp90依赖性伴侣活性可能在调控NOS3功能的机制中发挥关键作用，许多人认为这是两个独立的假设：1)hsp90依赖性信号调节NOS3的生成。NO（偶联活性）和O2。-（不耦合活动）；2)调节BH4水平，进而调节偶联和非偶联NOS3活性。本提案的总体目标是确定BN/Mcw大鼠心脏比SS/Mcw大鼠心脏更能抵抗缺血的细胞、分子和酶机制。通过阐明这些途径，本提案的发现将为hsp90伴侣活性如何增加NOS3提供新的、基本的见解。一氧化氮的产生增加对缺血的抵抗力。这些研究的观察结果可能实际上统一了心血管生理学中许多人认为相互竞争的两种假设，也可能导致缺血性心脏病治疗新策略的发展。