Disabled-2 is required for efficient hemostasis and platelet activation by thrombin in mice.
Disabled-2 is required for efficient hemostasis and platelet activation by thrombin in mice.
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在小鼠体内，Disabled-2 是凝血酶有效止血和血小板激活所必需的。
DOI：
10.1161/atvbaha.114.302602
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
Tseng,Ching-Ping
中科院分区：
文献类型：
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作者：
Tsai,Hui-Ju;Huang,Chien-Ling;Chang,Yao-Wen;Huang,Ding-Yuan;Lin,Chung-Ching;Cooper,JonathanA;Cheng,Ju-Chien;Tseng,Ching-Ping
目的血小板活化在止血和血栓性疾病中的重要作用主要集中在揭示血小板活化的潜在细胞内信号。被禁用的-2(DAB2)与血小板聚集和凝血反应的控制有关。方法与结果建立了巨核细胞系限制性DAB2基因敲除小鼠(DAB2−/−)，描述了DAB2在体内的功能。DAB2型−/−小鼠大小正常，出血时间延长，血栓形成受损。尽管在正常的血小板生成和颗粒生物生成中，DAB_2−/−血小板在低浓度凝血酶的反应下，可引起血小板聚集和扩散到纤维蛋白原上的选择性缺陷，而不是其他可溶性激动剂。对DAB2在凝血酶信号转导中作用的研究表明，DAB2对凝血酶受体的表达和由外向内的信号转导没有影响。经低浓度凝血酶刺激的DAB2RhoA-−/−血小板在GαQ介导的钙动员和蛋白激酶C活化方面正常，但在Gα12/13介导的RhoA-ROCKII活化方面存在缺陷。Gα12/13信号减弱导致腺苷二磷酸释放、雷帕霉素和整合素αIIbβ3激活、纤维蛋白原结合和凝块收缩受损。DAB2−/−对低浓度凝血酶刺激的异常反应可能参与了DAB2−/−小鼠的止血和血栓形成。结论本研究为血小板生物学提供了新的见解，并首次报道了DAB2通过与Gα12/13介导的凝血酶信号的功能相互作用而成为止血和血栓形成的关键调节因子。
ObjectiveThe essential role of platelet activation in hemostasis and thrombotic diseases focuses attention on unveiling the underlying intracellular signals of platelet activation. Disabled-2 (Dab2) has been implicated in platelet aggregation and in the control of clotting responses. However, there is not yet any in vivo study to provide direct evidence for the role of Dab2 in hemostasis and platelet activation.Approach and ResultsMegakaryocyte lineage-restricted Dab2 knockout (Dab2−/−) mice were generated to delineate in vivo functions of Dab2 in platelets. Dab2−/−mice appeared normal in size with prolonged bleeding time and impaired thrombus formation. Although normal in platelet production and granule biogenesis, Dab2−/−platelets elicited a selective defect in platelet aggregation and spreading on fibrinogen in response to low concentrations of thrombin, but not other soluble agonists. Investigation of the role of Dab2 in thrombin signaling revealed that Dab2 has no effect on the expression of thrombin receptors and the outside-in signaling. Dab2−/−platelets stimulated by low concentrations of thrombin were normal in Gαq-mediated calcium mobilization and protein kinase C activation, but were defective in Gα12/13-mediated RhoA-ROCKII activation. The attenuated Gα12/13signaling led to impaired ADP release, Akt-mammalian target of rapamycin and integrin αIIbβ3 activation, fibrinogen binding, and clot retraction. The defective responses of Dab2−/−platelets to low concentrations of thrombin stimulation may contribute to the impaired hemostasis and thrombosis of Dab2−/−mice.ConclusionsThis study sheds new insight in platelet biology and represents the first report demonstrating that Dab2 is a key regulator of hemostasis and thrombosis by functional interplay with Gα12/13-mediated thrombin signaling.