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Novel antithrombotic strategy based on the functional regulation of factor VIII/VWF complex

基于VIII因子/VWF复合物功能调节的新型抗血栓策略

基本信息

批准号：
17390304
负责人：
YOSHIOKA Akira
金额：
$ 10.54万
依托单位：
Nara Medical University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17390304/
关键词：
factor VIII VWF physiologic blood flow thrombosis flow chamber ADAMTS13 フローチロンバー

项目摘要

Fatal arterial thrombosis such as myocardial infarction or stroke is assumed to be triggered by hemostatic mechanisms which are originally essential for human defense. Hemostasis is established by the concerted functions of platelet adhesion/aggregation and blood coagulation mechanisms. Interestingly, von Willebrand factor (VWF) that plays a paramount role in platelet adhesion/aggregation is known to form a binary complex in plasma with the coagulation factor VIII which is the major blood coagulation factor. Thus, the purpose of the present study is to clarify the activation or inactivation mechanisms of this crucial molecular complex (factor VIII/VWF) under whole blood flow conditions, and to establish the novel antithrombotic strategy based on the functional regulation of factor VIII/VWF complex.With regard to the factor VIII regulation, we have studied the activation/inactivation of factor VIII by a fibrinolytic factor plasmin. As a result, the cleavage of Arg-336 within factor VIII … More molecule was thought to be a central mechanism of plasmin-catalyzed factor VIII inactivation. Thus, we suggest the presence of a regulatory role of plasmin through direct proteolitic reaction in the coagulation reaction as well as fibrinolytic activity.Next, with regard to the VWF regulation, we have studied the molecular mechanisms of ADAMTS13 activity under whole blood flow conditions, The proper function of VWF is essential for normal hemostasis, but the excessive function of VWF links to arterial thrombosis. ADAMTS13 is assumed to regulate the VWF function in vivo by reducing the multimer size that directly represents the thrombogenic activity of VWF, while the precise action mechanisms remain to be clarified. Using an in vitro perfusion chamber system, we have studied the ADAMTS13 activity on the process of platelet thrombus formation on a collagen surface under whole blood flow conditions. Inhibition studies with a function-blocking anti-ADAMTS13 antibody, combined with immunostaining of thrombi with an and-VWF monoclonal antibody that can specifically reflect the VWF-cleaving activity of ADAMTS13, demonstrated visual evidence for a shear-rate dependent action of ADAMTS13 that limits thrombus growth at the on-going thrombus generation process. Our results revealed a regulating mechanism on mural thrombogenesis to exquisitely prevent arterial occlusion under high shear rate conditions. Less

致命的动脉血栓形成，如心肌梗死或中风，被认为是由止血机制触发的，而止血机制最初是人体防御所必需的。止血是通过血小板粘附/聚集和凝血机制的协同作用来建立的。有趣的是，已知在血小板粘附/聚集中发挥重要作用的血管性血友病因子（VWF）在血浆中与主要凝血因子VIII形成二元复合物。因此，本研究的目的是阐明这种关键的分子复合物（凝血因子VIII/VWF）在全血流条件下的激活或失活机制，并建立新的抗血栓策略的基础上的功能调节凝血因子VIII/VWF复合物。结果，因子VIII内Arg-336的裂解 ...更多信息分子被认为是纤溶酶催化的因子VIII失活的中心机制。因此，我们认为纤溶酶通过直接的蛋白水解反应在凝血反应和纤溶活性中发挥调节作用。其次，关于VWF的调节，我们研究了全血流条件下ADAMTS 13活性的分子机制。VWF的正常功能是正常止血所必需的，但VWF的过度功能与动脉血栓形成有关。ADAMTS 13被认为是通过减少直接代表VWF血栓形成活性的多聚体大小来调节体内VWF功能，但确切的作用机制仍有待阐明。使用体外灌注室系统，我们研究了ADAMTS 13活性的血小板血栓形成过程中的胶原蛋白表面在全血流条件下。使用功能阻断抗ADAMTS 13抗体的抑制研究，结合使用能够特异性反映ADAMTS 13的VWF裂解活性的and-VWF单克隆抗体对血栓进行免疫染色，证明了ADAMTS 13的剪切速率依赖性作用的视觉证据，该作用限制了正在进行的血栓生成过程中的血栓生长。我们的研究结果揭示了在高剪切率条件下壁血栓形成的调节机制，以防止动脉闭塞。少