Thrombin signaling in Hemostasis and thrombosis

描述（由申请人提供）：我实验室的中心目标是确定凝血酶如何调节止血、血栓形成、炎症和其他过程中涉及的细胞行为，并阐明凝血酶信号传导在体内的作用。该补助金的重点是止血和血栓形成。我们以前的工作表明，蛋白酶激活受体（PARs）是必要的凝血酶激活血小板和血栓形成和止血小鼠模型的重要。这些和其他研究支持探索PAR拮抗作用用于预防或治疗人类血栓形成。我们现在提出的研究，以更详细地定义PAR的作用，并确定凝血酶信号如何整合与其他血小板活化和凝血机制在体内。我们要问：1）vWF、胶原和凝血酶是体内血小板活化的主要引发剂吗？这些途径如何相互作用？使用复杂的小鼠模型，我们将测试的假设，GPIb和GP-VI信号是必要的和足够的驱动血小板粘附和血管壁血栓形成在损伤部位，但PAR信号是必要的血栓远离血管壁的传播。将使用遗传学和药理学方法。还将探测PAR与P2 Y12和Tbxa 2 r（TP）的相互作用。2)凝血酶诱导的血小板活化和纤维蛋白形成在止血和血栓形成中如何相互作用？当凝血酶生成或活性降低或抑制时，它们的相对重要性是否会改变？我们将确定凝血酶激活血小板是否对凝血酶生成的传播和远离血管壁的纤维蛋白形成是重要的。我们还将询问在低凝血酶生成的情况下PAR信号传导的中断是否对血栓形成或止血具有协同作用。3)内皮细胞和造血细胞中组织因子表达在止血和血栓形成中的作用是什么？内毒素血症？这种组织因子的作用是否可以通过敲除凝血传播的替代机制来揭示或放大？组织因子的表达将在内皮和造血组织中被消除，以探测“循环组织因子”的来源和作用。这些研究将阐明止血和血栓形成的关键效应物如何相互作用。

DESCRIPTION (provided by applicant): A central goal of my laboratory has been to determine how thrombin regulates cellular behaviors involved in hemostasis, thrombosis, inflammation and other processes, and to elucidate the roles of thrombin signaling in vivo. This grant has focused on hemostasis and thrombosis. Our previous work showed that protease-activated receptors (PARs) are necessary for platelet activation by thrombin and important for thrombosis and hemostasis in mouse models. These and other studies support exploration of PAR antagonism for the prevention or treatment of thrombosis in humans. We now propose studies to define the roles of PARs in more detail and to determine how thrombin signaling integrates with other platelet activation and coagulation mechanisms in vivo. We shall ask: 1) Are vWF, collagen and thrombin the major initiators of platelet activation in vivo? How do these pathways interact? Using sophisticated mouse models, we will test the hypothesis that GPIb and GP-VI signaling is necessary and sufficient to drive platelet adhesion and juxtamural thrombus formation at a site of injury but that PAR signaling is necessary for propagation of the thrombus away from the vessel wall. Genetic and pharmacological approaches will be used. PAR interactions with P2Y12 and Tbxa2r (TP) will also be probed. 2) How do thrombin-induced platelet activation and fibrin formation interact in hemostasis and thrombosis? Does their relative importance change when thrombin generation or activity is reduced or inhibited? We shall determine whether platelet activation by thrombin is important for propagation of thrombin generation and fibrin formation away from the vessel wall. We shall also ask whether disruption of PAR signaling in the setting of low thrombin generation has synergistic effects on thrombosis or hemostasis. 3) What is the role of tissue factor expression in endothelial and hematopoietic cells in hemostasis and thrombosis? In endotoxemia? Can roles for such tissue factor be uncovered or amplified by knockout of alternative mechanisms for propagation of coagulation? Tissue factor expression will be ablated in endothelial and hematopoietic tissues to probe the source and roles of "circulating tissue factor". These studies will illuminate how key effectors of hemostasis and thrombosis interact.