PAR4 mediates platelet activation in venous thromboembolism

项目概要/摘要 静脉血栓形成（VT）及其主要并发症肺栓塞（PE）通常分为以下几类： 静脉血栓栓塞（VTE）。这种疾病每年影响近60万人，是世界上最大的疾病。 终末期心血管疾病和死亡的原因。VT由三个主要因素促进，即 魏尔啸三联征：高凝状态、内皮细胞功能障碍和血流停滞。现在认识 血小板扮演了一个关键的启动角色，其机制刚刚被揭示。高凝 和凝血酶生成是VT的主要危险因素， （PAR 4）促进促凝血血小板、磷脂酰丝氨酸（PS）暴露和随后的凝血酶 一代我认为血小板PAR 4是静脉血栓栓塞症的一个重要因素。这项提议的科学前提是 是基于我的初步数据显示，低反应性PAR 4单核苷酸多态性（SNP）（PAR 4- 在GWAS荟萃分析中，位于PAR 4细胞外环3的P310 L）与VTE风险较低相关。 此外，具有同源PAR 4-P322 L多态性的小鼠血小板在血小板聚集中表现出降低的聚集。 对凝血酶活化的反应，并最终显示降低的PAR 4受体反应性。这个的目标 建议是1）使用互补小鼠来确定PAR 4如何有助于VT起始和传播 模型，2）验证PAR 4作为治疗VT的靶点，3）定义PAR 4如何调节VT中的血小板功能。我 假设血小板上的PAR 4信号传导是VT的驱动因素，减少PAR 4信号传导或药理学作用 抑制将提供对静脉血栓栓塞的保护。我的目的是确定PAR 4在启动和传播中的作用， 静脉血栓我将使用3种互补的VT小鼠模型来建立PAR 4作为VT的主要贡献者。 不同血栓形成条件下的凝块形成。为了确定PAR 4反应性的水平， 血栓传播所必需的，我将使用3种具有不同水平PAR 4活性的小鼠模型：野生型， PAR 4-模拟人SNP的P322 L，和PAR 4-/-以完全去除PAR 4。此外，该提案 目的是确定PAR 4激活如何调节VTE中的血小板反应。我会用人血做微流体 室以及具有上述不同水平的PAR 4反应性的小鼠模型，以确定 PAR 4影响VT的发生发展。完成后，该提案将确定一个未确定的 PAR 4介导的血小板促凝活性背后的机制，可以提供一种新的治疗方法， 专为静脉血栓栓塞症患者设计。

PROJECT SUMMARY/ABSTRACT Venous thrombosis (VT) and its major complication, pulmonary embolism (PE), are often grouped together as venous thromboembolism (VTE). This disease affects nearly 600,000 individuals per year and is the leading cause of end-stage cardiovascular disease and death. VT is promoted by three major factors, known as Virchow’s triad: hypercoagulability, endothelial cell dysfunction, and stasis of blood flow. It is now recognized that platelets play a critical initiating role, and the mechanism is just now being uncovered. Hypercoagulation and thrombin generation are major risk factors for VT, and thrombin-activated protease activated receptor 4 (PAR4) promotes procoagulant platelets, phosphatidyl serine (PS) exposure, and subsequent thrombin generation. I propose that platelet PAR4 is an important contributor to VTE. The scientific premise of this proposal is based my preliminary data showing that a hypo-reactive PAR4 single nucleotide polymorphism (SNP) (PAR4- P310L) located in extracellular loop 3 of PAR4 is associated with a lower risk for VTE in a GWAS meta-analysis. Further, mouse platelets with a homologous PAR4-P322L polymorphism exhibit decreased aggregation in response to thrombin activation and ultimately show decreased PAR4 receptor reactivity. The goals of this proposal are 1) to determine how PAR4 contributes to VT initiation and propagation using complementary mouse models, 2) validate PAR4 as a target to treat VT 3) define how PAR4 modulates platelet function in VT. I hypothesize that PAR4 signaling on platelets is a driver of VT, and reduced PAR4 signaling or pharmacological inhibition will offer protection from VTE. I aim to determine the role of PAR4 in the initiation and propagation of venous thrombosis. I will use 3 complementary mouse models of VT to establish PAR4 as a major contributor of clot development under different thrombotic conditions. In order to determine the level of PAR4 reactivity necessary for thrombus propagation, I will use 3 mouse models with differing levels of PAR4 activity: wild-type, PAR4-P322L mimicking the human SNP, and PAR4 -/- to completely remove PAR4. Additionally, this proposal aims to define how PAR4 activation modulates platelet response in VTE. I will use human blood in microfluidic chambers as well as mouse models with varying levels of PAR4 reactivity described above to determine how PAR4 influences the development of VT. Upon completion, this proposal will identify an undetermined mechanism behind PAR4-mediated platelet procoagulant activity in VTE, which can provide a novel therapeutic target for patients with VTE.