Coordinated Membrane Ballooning and Procoagulant Spreading in Human Platelets
Coordinated Membrane Ballooning and Procoagulant Spreading in Human Platelets
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DOI：
10.1161/circulationaha.114.015036
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发表时间：
2015-10-13
期刊：
影响因子：
37.8
通讯作者：
Poole, Alastair W.
中科院分区：
文献类型：
--
作者：
Agbani, Ejaife O.;van den Bosch, Marion T. J.;Poole, Alastair W.
背景-血小板是止血过程的中心，在血管损伤部位迅速聚集并作为凝血病灶。在与内皮下基质相互作用时，血小板转化为气球样结构，作为止血反应的一部分。然而，目前还不清楚血小板如何以及为什么产生这些结构。我们着手确定的生理相关性和细胞和分子机制的血小板膜ballooning.Methods和结果，使用4维活细胞成像和电子显微镜，我们表明，人类血小板粘附胶原蛋白转化为磷脂酰丝氨酸暴露气球状结构与膨胀的宏观/微泡接触表面，通过一个过程，我们称之为促凝血扩散。我们发现，气球是机械和结构不同的膜起泡，并涉及破坏血小板微管细胞骨架和通货膨胀通过液体进入。与起泡不同，促凝血气球样变是不可逆的，是Na+、Cl-和水进入的结果。此外，膜气球与微粒的产生。抑制Na+，Cl-，或水进入受损气球，促凝血扩散，和微粒的产生，它也减少了当地凝血酶的产生。缺乏Ano-6表达的人斯科特综合征血小板也显示出膜膨胀的显著减少，这与氯离子进入过程中的作用一致。最后，乙酰唑胺的水进入衰减气球在体外的封锁，并显着抑制血栓形成在体内的小鼠模型thrombosis. Conclusions-膨胀和促凝血小板扩散的流体进入细胞驱动，并在血栓形成的局部凝血放大是重要的。
Background-Platelets are central to the process of hemostasis, rapidly aggregating at sites of blood vessel injury and acting as coagulation nidus sites. On interaction with the subendothelial matrix, platelets are transformed into balloonlike structures as part of the hemostatic response. It remains unclear, however, how and why platelets generate these structures. We set out to determine the physiological relevance and cellular and molecular mechanisms underlying platelet membrane ballooning.Methods and Results-Using 4-dimensional live-cell imaging and electron microscopy, we show that human platelets adherent to collagen are transformed into phosphatidylserine-exposing balloonlike structures with expansive macro/microvesiculate contact surfaces, by a process that we termed procoagulant spreading. We reveal that ballooning is mechanistically and structurally distinct from membrane blebbing and involves disruption to the platelet microtubule cytoskeleton and inflation through fluid entry. Unlike blebbing, procoagulant ballooning is irreversible and a consequence of Na+, Cl-, and water entry. Furthermore, membrane ballooning correlated with microparticle generation. Inhibition of Na+, Cl-, or water entry impaired ballooning, procoagulant spreading, and microparticle generation, and it also diminished local thrombin generation. Human Scott syndrome platelets, which lack expression of Ano-6, also showed a marked reduction in membrane ballooning, consistent with a role for chloride entry in the process. Finally, the blockade of water entry by acetazolamide attenuated ballooning in vitro and markedly suppressed thrombus formation in vivo in a mouse model of thrombosis.Conclusions-Ballooning and procoagulant spreading of platelets are driven by fluid entry into the cells, and are important for the amplification of localized coagulation in thrombosis.