PLATELET-DERIVED NITRIC OXIDE AND HEMOSTASIS

血小板源性一氧化氮和止血

• 批准号: 6537541
• 负责人: JANE E Freedman
• 金额: $ 25.84万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-07-01 至 2004-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6537541
• 关键词: enzyme activity; genetically modified animals; hemostasis; human subject; laboratory mouse; nitric oxide; nitric oxide synthase; oxidative stress; platelet activation; protein kinase C; thiols; thrombosis; tocopherols

DESCRIPTION (Adapted from Investigator's Abstract): Vessel injury and thrombus formation are the cause of most ischemic coronary syndromes. In this setting, platelet activation at the site of disrupted plaque leads to the recruitment of additional platelets and the evolution of the platelet-rich thrombus. In addition, patients with coronary atherosclerosis have impaired effective release of endothelial nitric oxide (NO), a known vasodilator and inhibitor of platelet function. While constitutive nitric oxide synthase (cNOS) has been identified in human platelets and megakaryoblastic cells and activated platelets elaborate NO, the role of platelet-derived NO in hemostasis has not been defined. Preliminary data demonstrates that stimulated platelets produce NO which inhibits recruitment and is present in decreased levels in patients with unstable coronary syndromes. The central hypothesis of this proposal is that the regulation of platelet-derived NO release alters platelet function, modulates vascular hemostasis, and influences the development of platelet-mediated thrombosis. To test this hypothesis, the following specific aims are proposed: 1) To further define the contribution of platelet-derived NO to platelet recruitment and determine its role in hemostasis and thrombosis in vivo using a genetic model of NO synthase deficiency. Using an existing genetic murine model of cNOS deficiency (targeted disruption of nitric oxide synthase isoform 3 (NOS3) gene), the significance of platelet-NO production will be explored at the molecular level; 2) To determine the biochemical and molecular mechanism(s) that regulate platelet-derived NO release. Preliminary data indicate that inhibition of PKC leads to enhanced release of platelet-derived NO. The interaction between this cell signaling pathway and platelet NO regulation will be examined; and 3) To characterize clinically relevant variables that influence the release of platelet-derived NO and determine the biochemical and molecular mechanism(s) responsible for these observations. In preliminary data, it has been shown that alpha-tocopherol and thiol levels (a measure of redox status) are independent predictors of platelet-derived NO in patients with unstable coronary syndromes. The effect of these antioxidants on platelet NO release and cNOS expression will be determined. Therefore, this proposal will study biochemical and molecular mechanism(s) by which platelet-derived NO influences hemostasis and may suggest a unique mechanism by which a platelet product modulates thrombosis and influences the manifestations of cardiovascular disease.

描述（改编自研究者摘要）：血管损伤和血栓 是大多数缺血性冠状动脉综合征的原因。在这种情况下， 血小板在斑块破裂部位的活化导致血小板聚集， 额外的血小板和富血小板血栓的形成。在 此外，冠状动脉粥样硬化患者的有效 内皮一氧化氮（NO）的释放，一种已知的血管扩张剂和 血小板功能虽然组成型一氧化氮合酶（cNOS）已被 在人血小板和巨核母细胞中鉴定， 血小板阐述了NO，血小板衍生的NO在止血中的作用还没有 被定义。初步数据表明，刺激血小板产生 抑制募集的NO，在患者中水平降低 不稳定冠状动脉综合征这一提议的核心假设是 血小板衍生的NO释放的调节改变了血小板功能， 调节血管止血，并影响 血小板介导的血栓形成。为了验证这一假设，以下具体 提出的目标是： 1)进一步明确血小板源性NO对血小板聚集的作用， 募集，并确定其在体内止血和血栓形成中的作用， NO合成酶缺乏症的遗传模型。使用现有的遗传小鼠模型 cNOS缺乏（靶向破坏一氧化氮合酶亚型3 （NOS 3）基因），将探讨血小板NO产生的意义 分子水平; 2)确定调节细胞凋亡的生物化学和分子机制， 血小板来源的NO释放。初步数据表明抑制PKC 导致血小板衍生的NO的释放增强。 将检查细胞信号传导途径和血小板NO调节;以及 3)表征影响释放的临床相关变量 血小板衍生的NO和确定的生化和分子机制（S） 负责这些观察。初步数据显示， α-生育酚和巯基水平（氧化还原状态的量度）是独立的 不稳定冠状动脉综合征患者血小板源性NO的预测因子 这些抗氧化剂对血小板NO释放和cNOS表达的影响 将被确定。 因此，本提案将通过以下方式研究生物化学和分子机制： 其中血小板衍生的NO影响止血，并可能提示一种独特的 血小板产品调节血栓形成并影响 心血管疾病的表现。