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）：我们对介导抗心肌缺血的机制的理解仍不清楚。为了确定增强缺血抵抗力的机制，我们将 Brown挪威 (BN/Mcw) 和 Dahl S (SS/Mcw) 大鼠的心脏置于整体缺血状态。 BN/Mcw 大鼠的心脏比 SS/Mcw 大鼠的心脏更能抵抗缺血。细胞机制检查表明，尽管两种品系大鼠的心脏表现出相同水平的内皮一氧化氮合酶 (NOS3) 和热休克蛋白 90 (hsp90) 表达，但 BN/Mcw 大鼠的心脏产生更多的一氧化氮 (.NO) 和更少的超氧化物阴离子 (02.-) 比 SS/Mcw 大鼠的心脏。基础蛋白质组学研究表明，BN/Mcw 心脏中 NO 和 O2.- 生成向 NO 转变的平衡至少部分是由于热休克蛋白 90 (hsp90) 与 NOS3 以及可能与 GTP 相关性的改变所致环水解酶 I (GTPCH-I)。我们观察到，与 SS/Mcw 心脏中的关联相比，BN/Mcw 心脏中 hsp90 与 NOS3 的关联增加了近 2 倍； BN/Mcw 心脏中的总生物蝶呤（四氢生物蝶呤 (BH4) 的分析指数）增加了 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 hsp90 的关联增加了 2.2 倍。这些数据表明，hsp90 依赖性伴侣活性可能在控制 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 依赖性信号传导调节 NOS3 生成 .NO（偶联活性）和 O2.-（非偶联活性）活动）; 2) 调节 BH4 水平，进而调节偶联和非偶联 NOS3 活性。该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，该提案的研究结果将为 hsp90 伴侣活性如何增加 NOS3 .NO 生成以增强对缺血的抵抗力提供​​新的基本见解。这些研究的观察结果实际上可能统一了许多人认为心血管生理学中相互竞争的两个假设，并且还可能导致治疗缺血性心脏病的新策略的开发。