VON WILLEBRAND FACTOR-INDUCED PLATELET ACTIVITY

这项建议的广泛和长期目标是获得更好的 了解血小板和血管之间的相互作用 其导致正常和病理性止血。 具体目标是 这项研究计划是确定生化的性质， 血小板对血管性血友病因子（vWF）的反应，在此过程中， 阐明的生理和病理生理后果的 vWF/血小板相互作用。 血小板-vWF的既往研究 相互作用主要集中在结构-功能上 vWF与血小板结合决定簇的关系 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 暴露于vWF后血小板的活化。 校长 研究人员花了两年的全职研究培训， 他在血小板信号转导领域的发展;他的赞助商 他是这一领域的知名研究者;他的合作者 在蛋白质化学和分子生物学方面的丰富经验， 人血管性血友病因子。 待检验的假设是vWF 与血小板的结合导致特异性细胞内信号， 引发或促进血小板活化和血栓形成。 的 实验设计是基于系统的性能， 细胞内过程的定量和时间测量， 导致血小板活化。 这些研究将侧重于 在通过vWF介导血小板活化的生化事件之后： (1)磷酸肌醇周转和磷酸肌醇的产生， 甘油二酯、磷脂酸和活化蛋白激酶C;（2） 胞质钙的变化;和（3）类花生酸的产生， 磷脂酶A2或磷脂酶C介导的磷脂水解。 这些测量将在以下条件下进行： （1）血管性血友病因子（天然的，去唾液酸化的， 重组分子）;（2）除vWF以外的血浆成分（例如， 纤维蛋白原、ADP和凝血酶）;和（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）。 通过 这些实验的结果将有可能开始减少 复杂的胞间和胞内过程， 止血与血小板粘附相关的关键事件 激活和聚集。

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.