The role of protease activated receptors on platelets

蛋白酶激活受体对血小板的作用

• 批准号: 10579822
• 负责人: Marvin Thomas Nieman
• 金额: $ 47.5万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-15 至 2025-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10579822
• 关键词: Affect; Alleles; Animal Model; Binding Sites; Biological; Biophysics; Blood; Blood Platelets; Blood flow; Collaborations; Complex; Complication; Data; Development; Disease; Endothelium; Generations; Genetic Polymorphism; Goals; Health; Human; Individual; Injury; Learning; Ligand Binding; Meta-Analysis; Microfluidic Microchips; Mission; Molecular; Multicellular Process; Mutate; Mutation; Pathologic; Pathway interactions; Persons; Physiological; Process; Proteinase-Activated Receptors; Public Health; Pulmonary Embolism; Qualifying; Relative Risks; Research; Risk Factors; Risk Reduction; Role; Serine; Signal Pathway; Signal Transduction; Single Nucleotide Polymorphism; Structure; Testing; Thrombin; Thrombosis; Thrombus; Translating; United States National Institutes of Health; Variant; Venous; Venous Thrombosis; antagonist; drug development; endothelial dysfunction; experience; extracellular; genome wide association study; in vivo; in vivo Model; inhibitor; innovation; insight; mouse model; mouse protease-activated receptor 4; neutrophil; pharmacologic; platelet function; prevent; programs; protease-activated receptor 3; protease-activated receptor 4; therapeutic target; validation studies; venous thromboembolism

PROJECT SUMMARY/ABSTRACT Venous thrombosis (VT) and its major complication, pulmonary embolism (PE), are often grouped together and called venous thromboembolism (VTE). VTE is a major health problem that affect nearly 600,000 people each year. The historical drivers of VTE are blood stasis, endothelial dysfunction, and hypercoagulation (Virchow’s triad). It is now recognized that platelets and neutrophils have a critical initiating role. The molecular mechanisms are only being uncovered. Given that hypercoagulation is a risk factor and thrombin activated protease activated receptor 4 (PAR4) promotes procoagulant platelets, phosphatidyl serine (PS) exposure and subsequent thrombin generation, we propose that PAR4 is an important contributor to VTE. The long-term goals of this research program are to uncover the mechanisms of PAR4 activation at the molecular level and test these mechanism in vivo to inform disease processes and potential drug development. The scientific premise of this proposal is based our preliminary data showing that extracellular loop 3 (ECL3) of PAR4 coordinates with the ligand binding site (LBS) during PAR4 activation. Further, mutations in either ECL3 or the LBS disrupt PAR4 signaling to the same degree. This points to an essential role for ECL3 in PAR4 activation. The overall objective of this proposal is to 1) to determine how PAR4 contributes to the initiation and propagation of venous thrombosis using mouse models, 2) conduct proof-of-concept studies using PAR4 antagonist to treat VT, 3) to translate our recent structural insights on the PAR4 activation mechanism to PAR4 function in vivo. We will do this by taking advantage a PAR4 variant in human platelets and a new mouse model. Our overall hypothesis is that the sustained signaling from PAR4 on platelets is a driver of VTE and reduced PAR4 signaling from hypo-reactive variants or pharmacological inhibitors will lead to protection from VTE. Our innovative approach will take advantage of a new mouse model that recreates a polymorphism in ECL3 and will allow us to determine the mechanism of how this polymorphism contributes to platelet function and thrombosis. The completion of the proposed studies will accomplish two major advances. 1) we will be the first to specifically examine the role of PAR4 in venous thrombosis. 2) we will continue to push our basic understanding of PAR activation mechanisms by testing the observations from our structural studies in vivo to determine how these mechanisms operate in physiological and pathophysiological contexts.

项目概要/摘要 静脉血栓形成 (VT) 及其主要并发症肺栓塞 (PE) 通常被归为一类， 称为静脉血栓栓塞（VTE）。 VTE 是一个影响近 60 万人的重大健康问题 年。 VTE 的历史驱动因素是血瘀、内皮功能障碍和高凝状态（Virchow’s 三合会）。现在人们认识到血小板和中性粒细胞具有关键的启动作用。分子机制 才刚刚被发现。鉴于高凝是一个危险因素，并且凝血酶激活的蛋白酶被激活 受体 4 (PAR4) 促进促凝血血小板、磷脂酰丝氨酸 (PS) 暴露以及随后的 凝血酶的产生，我们认为 PAR4 是 VTE 的重要贡献者。本次活动的长期目标 研究计划是在分子水平上揭示 PAR4 激活机制并测试这些机制 体内机制以告知疾病过程和潜在的药物开发。这样做的科学前提 该提案基于我们的初步数据，表明 PAR4 的细胞外环 3 (ECL3) 与 PAR4 激活过程中的配体结合位点 (LBS)。此外，ECL3 或 LBS 的突变会破坏 PAR4 发出相同程度的信号。这表明 ECL3 在 PAR4 激活中发挥重要作用。总体目标 该提案的目的是 1) 确定 PAR4 如何促进静脉血栓形成的发生和传播 使用小鼠模型，2）使用 PAR4 拮抗剂治疗 VT 进行概念验证研究，3）转化我们的研究成果 关于 PAR4 体内功能的 PAR4 激活机制的最新结构见解。我们将通过以下方式做到这一点 利用人类血小板中的 PAR4 变体和新的小鼠模型。我们的总体假设是 血小板上 PAR4 的持续信号传导是 VTE 的驱动因素，低反应性导致 PAR4 信号传导减少 变体或药理学抑制剂将导致预防 VTE。我们的创新方法将采取 一种新的小鼠模型的优势在于，该模型在 ECL3 中重新创建了多态性，并使我们能够确定 这种多态性如何促进血小板功能和血栓形成的机制。完成 拟议的研究将取得两项重大进展。 1）我们将首先具体考察的作用 PAR4在静脉血栓形成中的作用。 2）我们将继续推动我们对PAR激活机制的基本理解 通过测试我们体内结构研究的观察结果，以确定这些机制如何运作 生理和病理生理背景。