Pharmacological Blockade of Glycoprotein VI Promotes Thrombus Disaggregation in the Absence of Thrombin
Pharmacological Blockade of Glycoprotein VI Promotes Thrombus Disaggregation in the Absence of Thrombin
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DOI：
10.1161/atvbaha.120.314301
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发表时间：
2020-09-01
影响因子：
8.7
通讯作者：
Mangin, Pierre H.
中科院分区：
文献类型：
--
作者：
Ahmed, Muhammad Usman;Kaneva, Valeria;Mangin, Pierre H.
目的：动脉粥样硬化血栓发生在动脉粥样硬化斑块破裂并导致壁血栓的形成。计算流体动力学和数值模型表明，施加在血栓上的机械应力随着血栓的生长而急剧增加，并且血小板之间强烈的相互作用对于维持血栓的稳定性至关重要。我们通过实时视频显微镜研究了GPVI（糖蛋白VI）介导的血小板激活是否有助于维持血栓的稳定性。方法和结果：我们发现，在没有凝血酶的情况下，用2种不同的Fab片段阻断GPVI可促进胶原蛋白或动脉粥样硬化斑块物质上形成的人血栓的有效分解。在动脉血流条件下，act017诱导的分解作用得以实现，其作用随壁剪切速率的增加而增强。当GPVI被阻断时，血栓收缩丧失，当溶性激动剂完全激活血栓时，抗GPVI药物没有分解作用，这证明了GPVI调节生长血栓中的血小板活化。gpvi依赖性的血栓稳定作用进一步得到以下事实的支持：抑制4种关键免疫受体酪氨酸基基信号分子（src-激酶、Syk、PI3K β或磷脂酶C）中的任何一种，都会导致血栓分解动力学类似于ACT017。在2例纤原性患者中，没有act017诱导的血栓分解表明GPVI的作用需要与纤维蛋白原相互作用。最后，ACT017联合r-tPA（重组组织型纤溶酶原激活剂）也能促进富纤维蛋白血栓的血小板分解。结论：这项研究发现了GPVI在维持血栓稳定性方面的一个未被认识的作用，并表明靶向GPVI可以溶解纤维蛋白含量低的血小板聚集体。
Objective: Atherothrombosis occurs upon rupture of an atherosclerotic plaque and leads to the formation of a mural thrombus. Computational fluid dynamics and numerical models indicated that the mechanical stress applied to a thrombus increases dramatically as a thrombus grows, and that strong inter-platelet interactions are essential to maintain its stability. We investigated whether GPVI (glycoprotein VI)-mediated platelet activation helps to maintain thrombus stability by using real-time video-microscopy. Approach and Results: We showed that GPVI blockade with 2 distinct Fab fragments promoted efficient disaggregation of human thrombi preformed on collagen or on human atherosclerotic plaque material in the absence of thrombin. ACT017-induced disaggregation was achieved under arterial blood flow conditions, and its effect increased with wall shear rate. GPVI regulated platelet activation within a growing thrombus as evidenced by the loss in thrombus contraction when GPVI was blocked, and the absence of the disaggregating effect of an anti-GPVI agent when the thrombi were fully activated with soluble agonists. The GPVI-dependent thrombus stabilizing effect was further supported by the fact that inhibition of any of the 4 key immunoreceptor tyrosine-based motif signalling molecules, src-kinases, Syk, PI3K beta, or phospholipase C, resulted in kinetics of thrombus disaggregation similar to ACT017. The absence of ACT017-induced disaggregation of thrombi from 2 afibrinogenemic patients suggests that the role of GPVI requires interaction with fibrinogen. Finally, platelet disaggregation of fibrin-rich thrombi was also promoted by ACT017 in combination with r-tPA (recombinant tissue plasminogen activator). Conclusions: This work identifies an unrecognized role for GPVI in maintaining thrombus stability and suggests that targeting GPVI could dissolve platelet aggregates with a poor fibrin content.