Collagen but not fibrinogen surfaces induce bleb formation, exposure of phosphatidylserine, and procoagulant activity of adherent platelets: evidence for regulation by protein tyrosine kinase-dependent Ca2+ responses.
Collagen but not fibrinogen surfaces induce bleb formation, exposure of phosphatidylserine, and procoagulant activity of adherent platelets: evidence for regulation by protein tyrosine kinase-dependent Ca2+ responses.
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DOI：
10.1182/blood.v90.7.2615
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发表时间：
1997-10
期刊：
影响因子：
20.3
通讯作者：
J. Heemskerk;W. Vuist;M. Feijge;C. Reutelingsperger;T. Lindhout
中科院分区：
文献类型：
--
作者：
J. Heemskerk;W. Vuist;M. Feijge;C. Reutelingsperger;T. Lindhout
结合相衬和荧光视频成像系统，形态学和胞浆[Ca 2 +]i的变化进行了研究的Fura-2负载血小板粘附纤维蛋白原或胶原基质。Ca 2+信号，在单个血小板的水平上，分泌和促凝反应相比，使用荧光标记的AK-6抗体对P-选择素和标记的膜联蛋白V检测表面暴露的磷脂酰丝氨酸（PS），分别。与纤维蛋白原接触的血小板形成丝状体并遍布基质，在大多数细胞中没有可检测到的Ca 2+信号。凝血酶诱导[Ca 2 +]i的重复尖峰，随后在血小板表面上表达P-选择素，但不表达PS。血小板与胶原蛋白的相互作用导致细胞扩散并转化为起泡的“气球”样结构（直径约5微米）。后者的形态变化伴随着高和长期增加[Ca 2 +]i，由P-选择素和PS的曝光，并通过血小板的能力，凝血酶原转化为凝血酶。凝血酶的加入加速了Ca 2+信号的出现和表面暴露的PS的出现。胶原诱导的PS曝光略有减少，用阿司匹林治疗的血小板，并强烈抑制抑制的Ca 2+反应与前列腺素E1或Ca 2+螯合剂，二甲基-BAPTA。用染料木黄酮、U 73343或渥曼青霉素抑制蛋白酪氨酸磷酸化导致许多血小板中的Ca 2+反应增加，并且几乎完全减少了滤过泡形成和PS暴露。与此相反，染料木黄酮没有抑制水泡形成和PS暴露的血小板刺激的钙离子载体A23187。我们的结论是，胶原蛋白，而不是纤维蛋白原基质作为一个有效的激活剂的促凝血反应，通过激活酪氨酸激酶和随后产生持续的细胞内Ca 2+信号。
With a combined phase-contrast and fluorescence video imaging system, changes in morphology and cytosolic [Ca2+]i were investigated of fura-2-loaded platelets during adhesion to fibrinogen or collagen matrices. The Ca2+ signals were, on the level of single platelets, compared to the secretion and procoagulant responses, using fluorescent-labeled AK-6 antibody against P-selectin and labeled annexin V for detection of surface-exposed phosphatidylserine (PS), respectively. Platelets in contact with fibrinogen developed filapods and spread over the matrix, in most of the cells without detectable Ca2+ signal. Thrombin induced repetitive spiking in [Ca2+]i, followed by the expression of P-selectin but not of PS on the platelet surface. Platelet interaction with collagen resulted in spreading and transformation of the cells into blebbing, "balloon"-like structures (diameter about 5 microm). The latter morphological changes were accompanied by high and prolonged increases in [Ca2+]i, by the exposure of both P-selectin and PS, and by the ability of the platelets to convert prothrombin into thrombin. Thrombin addition accelerated the onset of the Ca2+ signals and the appearance of surface-exposed PS. Collagen-induced PS exposure was slightly reduced by treatment of the platelets with aspirin, and strongly inhibited by suppression of the Ca2+ responses with prostaglandin E1 or the Ca2+ chelator, dimethyl-BAPTA. Inhibition of protein tyrosine phosphorylation with genistein, U73343, or wortmannin resulted in spiking Ca2+ responses in many of the platelets and in almost complete reduction of bleb formation and PS exposure. In contrast, genistein did not suppress bleb formation and PS exposure of platelets stimulated with the Ca2+ ionophore A23187. We conclude that a collagen but not fibrinogen matrix acts as a potent activator of the procoagulant response through activation of tyrosine kinases and subsequent generation of sustained intracellular Ca2+ signals.