ERO1 alpha in platelet activity and thrombosis

项目摘要 尽管我们对介导血小板血栓形成的机制的了解取得了进展，但目前 抗血小板药物会增加大出血的风险。为了努力寻找新的治疗靶点，我们和 另有研究表明，血管内蛋白二硫键异构酶(Pdi)对αIIbβ3整合素的充分激活至关重要。 和动脉血栓形成中的血小板聚集，为新的抗血栓药物提供了洞察力。然而， 阻断血管内PDI氧化还原酶活性可延长小鼠尾巴出血时间。我们的预赛 研究表明，内质网氧化还原蛋白1α(ERO 1α)是内质网氧化还原蛋白1的关键氧化酶。 ER是从激活的血小板中释放出来的，抑制或缺失血小板ER1α会改变其活性 与血小板表面结合的PDI和损害血小板聚集功能。此外，我们发现全球范围内 删除ERO 1α可减少血小板血栓形成的大小，而不影响最初的血小板黏附和 血管损伤后的尾巴出血时间。利用生化、细胞和活体动物研究 我们实验室开发的药物抑制剂和ERO1α条件基因敲除和全局基因敲除小鼠，我们 将验证这样的假设，即血小板释放的ERO 1α调节细胞上PDI和αIIbβ3整合素的功能 在不影响止血的情况下，促进了血小板血栓形成的传播步骤 在血管损伤之后。在目标1中，我们将确定细胞外ERO 1α的分子机制 促进血小板聚集。在目标2中，我们将测试动脉血栓形成情况是否改变血管功能 胞外Ero1α。在目标3中，我们将确定血管内和血小板来源的病理生理学作用。 Ero1α在血栓形成条件下的血小板黏附和积聚及血管闭塞中的作用建议数 研究将确定血小板血栓形成的中央调节机制，并导致发现 安全有效地治疗血栓性疾病的新治疗策略。

Project Summary Despite advances in our understanding of the mechanisms mediating platelet thrombus formation, current antiplatelet drugs increase the risk of major bleeding. In an effort to identify novel therapeutic targets, we and others showed that intravascular protein disulfide isomerase (PDI) is crucial for full activation of αIIbβ3 integrin and platelet accumulation in arterial thrombosis, providing insights into a new antithrombotic agent. However, blocking the oxidoreductase activity of intravascular PDI prolongs tail bleeding times in mice. Our preliminary data have demonstrated that endoplasmic reticulum (ER) oxidoreductin 1α (Ero1α), a key oxidase of PDI in the ER, is released from activated platelets and that inhibition or deletion of platelet Ero1α alters the activity of platelet surface-bound PDI and impairs platelet aggregatory function. Furthermore, we have found that global deletion of Ero1α reduces the size of platelet thrombus formation without affecting initial platelet adhesion and tail bleeding times following vascular injury. Using biochemical, cellular and in vivo animal studies with novel pharmacological inhibitors and Ero1α conditional knockout and global knockout mice developed by our lab, we will test the hypothesis that platelet-released Ero1α regulates the function of PDI and αIIbβ3 integrin on the cell surface and contributes to the propagation step of platelet thrombus formation without affecting hemostasis following vascular injury. In Aim 1, we will identify the molecular mechanism by which extracellular Ero1α promotes platelet aggregation. In Aim 2, we will test whether arterial thrombotic conditions alter the function of extracellular Ero1α. In Aim 3, we will determine the pathophysiological role of intravascular and platelet-derived Ero1α in platelet adhesion and accumulation and vessel occlusion under thrombotic conditions. The proposed studies will identify a central regulatory mechanism of platelet thrombus formation and lead to the discovery of novel therapeutic strategies for the safe and effective treatment of thrombotic disease.