Involvement of glycoprotein VI in platelet thrombus formation on both collagen and von Willebrand factor surfaces under flow conditions
Involvement of glycoprotein VI in platelet thrombus formation on both collagen and von Willebrand factor surfaces under flow conditions
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DOI：
10.1161/01.cir.0000021427.87256.7e
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发表时间：
2002-07-09
期刊：
影响因子：
37.8
通讯作者：
Takayama, H
中科院分区：
文献类型：
--
作者：
Goto, SY;Tamura, N;Takayama, H
背景-我们研究了流动条件下糖蛋白（GP）VI在固定化胶原和血管性血友病因子（vWF）表面的血小板粘附和血栓形成中的作用。方法和结果-从2例GP VI缺陷血小板患者获得全血，并检测了抗GP VI抗体的Fab（Fab/抗GP VI）的作用。在受控的壁剪切速率下，将含有由mepacrine呈现荧光的血小板的血液灌注到固定的I型胶原或vWF上。通过落射荧光视频显微镜检测血小板粘附和血栓形成。计算血小板的表面覆盖百分比。 Fc 受体 γ 链和脾酪氨酸激酶 (Syk) 从 vWF 加瑞斯托菌素刺激的血小板裂解物中进行免疫沉淀，然后通过抗磷酸酪氨酸免疫印迹进行分析。即使在相对低（100 s(-1)）或高（1500 s(-1)）壁剪切速率下灌注血液 9 分钟后，无论是在含有 GP VI 缺陷血小板的血液中还是在存在 Fab/抗 GP VI 的情况下，在胶原蛋白表面上都没有看到血小板附着，而在对照血液灌注后注意到显着的血小板血栓形成。这种对 GP VI 作用的干扰也降低了血小板对固定化 vWF 的牢固粘附。在正常血小板中，vWF诱导GP VI相关Fc受体γ链酪氨酸磷酸化，随后Syk激活，而在GP VI缺陷的血小板中，几乎没有发生Syk激活。 结论：GP VI在人体流动条件下胶原蛋白表面血小板血栓形成中起着至关重要的作用，也参与血小板在vWF表面牢固粘附的过程。
Background-We studied the role of glycoprotein (GP) VI in platelet adhesion and thrombus formation on the immobilized collagen and von Willebrand factor (vWF) surface under flow conditions.Methods and Results-Whole blood obtained from 2 patients with GP VI-deficient platelets and the effects of the Fab of anti-GP VI antibody (Fab/anti-GP VI) were tested. Blood containing platelets rendered fluorescent by mepacrine was perfused on immobilized type I collagen or vWF under controlled wall shear rate. Platelet adhesion and thrombus formation were detected by epifluorescent videornicroscopy. The percentage of surface coverage by the platelets was calculated. Fc receptor gamma-chain and spleen tyrosine kinase (Syk) were immunoprecipitated from the lysate of platelets stimulated by vWF plus ristocetin and then analyzed by antiphosphotyrosine immunoblotting. No platelet attachment was seen on the surface of collagen even after 9 minutes of perfusion of blood at relatively low (100 s(-1)) or high (1500 s(-1)) wall shear rate, either in the case of blood containing GP VI-deficient platelets or in the presence of Fab/anti-GP VI, whereas significant platelet thrombus formation was noted after control blood perfusion. Such interference with the actions of GP VI also reduced firm platelet adhesion on immobilized vWF. vWF-induced tyrosine phosphorylation of GP VI-associated Fc receptor gamma-chain followed by Syk activation occurred in normal platelets, but little activation of Syk occurred in GP VI-deficient platelets.Conclusions-GP VI plays crucial roles in platelet thrombus formation on the surface of collagen under flow conditions in humans and is also involved in the process of firm platelet adhesion on the surface of vWF.