Targeting Platelet GPIbβ Reduces Platelet Adhesion, GPIb Signaling and Thrombin Generation and Prevents Arterial Thrombosis
Targeting Platelet GPIbβ Reduces Platelet Adhesion, GPIb Signaling and Thrombin Generation and Prevents Arterial Thrombosis
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DOI：
10.1161/atvbaha.112.301013
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发表时间：
2013-06-01
影响因子：
8.7
通讯作者：
Mangin, Pierre H.
中科院分区：
文献类型：
--
作者：
Maurer, Eric;Tang, Chaojun;Mangin, Pierre H.
糖蛋白（GP）Ib-V-IX复合物调节血小板的粘附、活化和促凝活性。我们之前报道过RAM。1，一种针对小鼠GPIb β细胞外结构域的大鼠单克隆抗体，在流动条件下减少了血小板和用人GPIb-IX复合物转染的中国仓鼠卵巢细胞与血管性血友病因子的粘附。在这里，我们通过研究RAM的影响进一步评估了GPIb beta的功能重要性。1对GPIb介导的血小板反应和体外和体内血栓形成的影响。1显着减少GPIb介导的丝状伪足延伸的中国仓鼠卵巢GPIb-IX细胞粘附后，冯维勒布兰德因子。RAM. 1也减少丝状伪足的延伸和GPIb介导的Ca 2+信号后，小鼠血小板粘附到von Willebrand因子。RAM. 1抑制富血小板血浆中凝血酶的生成，而不损害磷脂酰丝氨酸暴露。此外，RAM.1以剪切依赖性方式在胶原蛋白上灌注小鼠全血后减少血栓形成。这种效应在体内得到证实，因为注射RAM 1的F（ab）2片段减少了由肠系膜小动脉的激光束损伤和腹主动脉的镊子损伤诱导的血栓形成。相反，RAM 1F（ab）2不延长尾部出血时间或增加失血量。结论-这些发现是靶向GPIb α以外的亚基可通过GPIb-V-IX复合物导致抗血栓形成作用的第一个证据。这可能代表了减少血栓形成的替代方法，对止血的影响较小。
Objective-The glycoprotein (GP) Ib-V-IX complex regulates the adhesion, activation, and procoagulant activity of platelets. We previously reported that RAM. 1, a rat monoclonal antibody directed against the extracellular domain of mouse GPIb beta, diminished adhesion of platelets and chinese hamster ovary cells transfected with the human GPIb-IX complex to von Willebrand factor under flow conditions. Here, we further evaluated the functional importance of GPIb beta by studying the impact of RAM. 1 on GPIb-mediated platelet responses and in vitro and in vivo thrombus formation.Approach and Results-We show that RAM. 1 dramatically reduced GPIb-mediated filopodia extension of chinese hamster ovary GPIb-IX cells after adhesion to von Willebrand factor. RAM. 1 also reduced filopodia extension and GPIb-mediated Ca2+ signaling after adhesion of mouse platelets to von Willebrand factor. RAM. 1 inhibited thrombin generation in platelet-rich plasma without impairing phosphatidylserine exposure. In addition, RAM.1 reduced thrombus formation after perfusion of mouse whole blood over collagen in a shear-dependent manner. This effect was confirmed in vivo, because injection of F(ab)'2 fragments of RAM.1 diminished thrombus formation induced by laser beam injury of mesenteric arterioles and forceps injury of the abdominal aorta. In contrast, RAM.1 F(ab)'2 did not prolong the tail-bleeding time or increase the volume of blood lost.Conclusions-These findings are the first evidence that targeting a subunit other than GPIb alpha can lead to an antithrombotic effect via the GPIb-V-IX complex. This could represent an alternative way to reduce thrombus formation with a minor impact on hemostasis.