Functional self-association of von Willebrand factor during platelet adhesion under flow
Functional self-association of von Willebrand factor during platelet adhesion under flow
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DOI：
10.1073/pnas.012459599
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发表时间：
2002-01-08
影响因子：
11.1
通讯作者：
Ruggeri, ZM
中科院分区：
文献类型：
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作者：
Savage, B;Sixma, JJ;Ruggeri, ZM
我们已经使用重组野生型人血管性血友病因子（VWF）和缺失突变体缺乏A1和A3域，以及特定的功能阻断单克隆抗体，以证明在可溶性和表面结合的VWF的接口功能相关的自关联。当血小板与红细胞处于无血浆悬浮液中时，以1,500 s（-1）的壁剪切速率灌注在缺乏A1结构域功能的固定化VWF上的血小板不能被束缚在表面上，但如果将具有功能性A1结构域的可溶性VWF加入细胞中，则迅速粘附。当VWF通过其A3结构域固定在胶原上时，观察到相同的结果，并将缺失A3结构域的可溶性VWF加入细胞中。因此，与玻璃或胶原结合的VWF维持与可溶性VWF多聚体的同型自缔合过程，其结果是可以介导血小板粘附。后一个发现表明，直接固定在基板上是不是一个严格的要求VWF结合血小板糖蛋白Ibalpha。表面结合和可溶性VWF的动态和可逆的相互作用似乎是特别同型的，因为固定化BSA，人纤维蛋白原，和纤连蛋白不能取代VWF的过程中。我们的研究结果强调了一个新认识的作用，循环VWF在血小板粘附的启动。VWF多聚体在受损血管表面上的自组装可能对阻止流动的血小板抵抗血液动力学力提供相关贡献，从而促进随后的血栓生长。
We have used recombinant wild-type human von Willebrand factor (VWF) and deletion mutants lacking the A1 and A3 domains, as well as specific function-blocking monoclonal antibodies, to demonstrate a functionally relevant self-association at the interface of soluble and surface-bound VWF. Platelets perfused at the wall shear rate of 1,500 s(-1) over immobilized VWF lacking A1 domain function failed to become tethered to the surface when they were in a plasma-free suspension with erythrocytes, but adhered promptly if soluble VWF with functional A1 domain was added to the cells. The same results were observed when VWF was immobilized onto collagen through its A3 domain and soluble VWF with deleted A3 domain was added to the cells. Thus, VWF bound to glass or collagen sustains a process of homotypic self-association with soluble VWF multimers that, as a result, can mediate platelet adhesion. The latter finding demonstrates that direct immobilization on a substrate is not a strict requirement for VWF binding to platelet glycoprotein Ibalpha. The dynamic and reversible interaction of surface-bound and soluble VWF appears to be specifically homotypic, because immobilized BSA, human fibrinogen, and fibronectin cannot substitute for VWF in the process. Our findings highlight a newly recognized role of circulating VWF in the initiation of platelet adhesion. The self-assembly of VWF multimers on an injured vascular surface may provide a relevant contribution to the arrest of flowing platelets opposing hemodynamic forces, thus facilitating subsequent thrombus growth.