MECHANISMS ON VON WILLEBRAND FACTOR-INDUCED PLATELET ACT

这项建议的广泛、长期目标是获得更好的 对血小板与血管相互作用的认识 导致正常止血和病理止血。的具体目的 这项研究计划是为了确定生化的性质 血小板对von Willebrand因子(VWF)的反应，在这样做的过程中， 阐明高血压的生理学和病理生理学后果 VWF/血小板相互作用。血小板-vWF的研究进展 相互作用主要集中在结构-功能上 血管性血友病因子及其与血小板结合的决定因素 膜受体；相比之下，这项拟议的研究将主要 研究信号-反应耦合的机制和途径 暴露于vWF后的血小板活化。校长 调查员花了两年的全职研究培训来 他在血小板信号转导领域的发展；他的赞助人 是这一领域的知名研究人员；他的合作者 在蛋白质化学和分子生物学方面有丰富的经验 人类冯·威勒布兰德因子。需要检验的假设是vWF 与血小板的结合会产生特定的细胞内信号， 启动或促进血小板活化和血栓形成。这个 实验设计是基于系统性能的 对细胞内过程的定量和时间测量 导致了血小板的激活。这些研究将集中在 VWF介导血小板活化的下列生化事件： (1)磷脂酰肌醇周转和肌醇磷酸盐的产生， 二酰基甘油、磷脂酸和活化蛋白激酶C； 胞质钙的变化；以及(3)从 磷脂酶A2或磷脂酶C介导的磷脂水解。 这些测量将在下列情况下进行 是不同的：(1)冯·威勒布兰德因子(天然的、期望的和 重组分子)；(2)vWF以外的血浆成分(如 纤维蛋白原、ADP和凝血酶)；以及(3)完整的人血小板(正常 并且具有改变的表面糖蛋白结构或功能)。穿过 这些实验的结果将有可能开始减少 复杂的细胞间和细胞内过程是主要特征 血小板与血小板黏附的关键事件的止血作用 激活和聚合。

The broad, long-term objective of this proposal is to gain a better understanding of the interactions between platelets and blood vessels which result in normal and pathologic hemostasis. The specific aim of this research plan is to determine the nature of the biochemical responses of platelets to von Willebrand factor (vWF) and, in so doing, elucidate the physiologic and pathophysiologic consequences of the vWF/platelet interaction. Previous investigations of platelet-vWF interactions have focused predominantly on the structure-function relationships of vWF and the determinants of its binding to platelet membrane receptors; this proposed research, in contrast, will primarily examine the mechanisms of signal-response coupling and pathways of activation of platelets following exposure of vWF. The principal investigator has spent two years of full-time research training towards his development in the field of platelet signal transduction; his sponsor is an established investigator in this field; and his collaborators have extensive experience in the protein chemistry and molecular biology of human von Willebrand factor. The hypothesis to be tested is that vWF binding to platelets results in specific intracellular signals that initiate or promote platelet activation and thrombus formation. The experimental design is based on the systematic performance of quantitative and temporal measurements of intracellular processes that result in platelet activation. The studies will focus on the role of the following biochemical events in mediating platelet activation by vWF: (1) phosphoinositide turnover and the generation of inositol phosphates, diacylglycerol, phosphatidic acid, and activated protein kinase C; (2) changes in cytosolic calcium; and (3) eicosanoid production from phospholipase A2- or phospholipase C-mediated phospholipid hydrolysis. These measurements will be made under conditions in which the following are varied: (1) the von Willebrand factor (native, desialylated, and recombinant molecules); (2) plasma constituents other than vWF (e.g. fibrinogen, ADP, and thrombin); and (3) the intact human platelet (normal and with altered surface glycoprotein structure or function). Through the results of these experiments it will be possible to begin to reduce the complex inter-and intracellular processes which characterize primary hemostasis to the critical events linking platelet adhesion to platelet activation and aggregation.