PLATELET-DERIVED NITRIC OXIDE AND HEMOSTASIS

血小板源性一氧化氮和止血

• 批准号: 6638523
• 负责人: JANE E Freedman
• 金额: $ 26.62万
• 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 2005-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6638523
• 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《调查者摘要》)：血管损伤和血栓 形成是大多数缺血性冠脉综合征的原因。在这种情况下， 斑块破裂部位的血小板活化导致 额外的血小板和富含血小板的血栓的演变。在……里面 此外，冠状动脉粥样硬化患者的疗效也有所减弱。 内皮一氧化氮(NO)的释放，一种已知的血管扩张剂和血管紧张素转换酶抑制剂 血小板功能。而结构型一氧化氮合酶(CNOS)一直是 在人血小板和巨核母细胞中鉴定并激活 血小板分泌NO，血小板源性NO在止血中的作用尚未见报道 已经被定义了。初步数据显示，受刺激的血小板产生 抑制募集的NO在患者体内的水平降低 患有不稳定的冠脉综合征。这项提议的中心假设是 调节血小板衍生的NO释放改变了血小板的功能， 调节血管止血，影响血管病变的发展 血小板介导的血栓形成。为了检验这一假设，以下是具体的 建议的目标是： 1)进一步明确血小板源性一氧化氮对血小板的作用 募集并确定其在体内止血和血栓形成中的作用 一氧化氮合酶缺乏症的遗传模型。使用现有的遗传小鼠模型 CNOS缺乏症(一氧化氮合酶亚型3的靶向干扰 (NOS3基因)，血小板-NO产生的意义将在 分子水平； 2)确定调控的生化和分子机制(S) 血小板来源的NO释放。初步数据表明，PKC的抑制 导致血小板衍生的NO释放增强。它们之间的相互作用 将研究细胞信号通路和血小板NO调节；以及 3)确定影响药物释放的临床相关变量 血小板源性一氧化氮及其生化和分子机制的确定(S) 对这些观察负责。在初步数据中，已经表明 α-生育酚和硫醇水平(氧化还原状态的衡量标准)是独立的。 不稳定冠脉综合征患者血小板衍生一氧化氮的预测因素。 抗氧化剂对血小板NO释放及cNOS表达的影响 将会被确定。 因此，这项建议将通过以下方式来研究生化和分子机制(S) 哪种血小板衍生的NO影响止血并可能提示独特的 血小板产物调节血栓形成并影响血管内皮生长的机制 心血管疾病的表现。