Blocking the protease-activated receptor 1-4 heterodimer in platelet-mediated thrombosis
Blocking the protease-activated receptor 1-4 heterodimer in platelet-mediated thrombosis
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DOI：
10.1161/circulationaha.105.587758
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发表时间：
2006-03-07
期刊：
影响因子：
37.8
通讯作者：
Kuliopulos, A
中科院分区：
文献类型：
--
作者：
Leger, AJ;Jacques, SL;Kuliopulos, A
凝血酶是最有效的血小板激动剂，在动脉血栓形成中起着关键作用。人血小板表达双凝血酶受体，蛋白酶激活受体（PAR）1和PAR 4，然而，有没有有效地靶向两个receptors.Methods和结果的治疗策略-血小板聚集研究表明，PAR 4活性显着增强凝血酶-PAR 1的相互作用。比伐卢定（hirulog）与新型PAR 4肽转运蛋白拮抗剂P4pal-i1的组合可有效抑制人血小板聚集至甚至高浓度的凝血酶，并防止豚鼠颈动脉闭塞。同样地，PAR 1和PAR 4与小分子拮抗剂和pepducins的联合抑制对颈动脉闭塞有效。免疫共沉淀和荧光共振能量转移研究表明，PAR 1和PAR 4作为异二聚体复合物在人血小板和成纤维细胞中缔合。PAR 1-PAR 4共因子化通过加速凝血酶裂解和PAR 4与PAR 1共表达时的信号传导来显示。结论-我们表明PAR 1和PAR 4形成稳定的异源二聚体，使凝血酶能够作为二价功能激动剂。这些研究表明，靶向PAR 1-PAR 4复合物可能为预防动脉血栓形成提供新的治疗机会。
Background - Thrombin is the most potent agonist of platelets and plays a critical role in the development of arterial thrombosis. Human platelets express dual thrombin receptors, protease-activated receptor (PAR) 1 and PAR4; however, there are no therapeutic strategies that effectively target both receptors.Methods and Results - Platelet aggregation studies demonstrated that PAR4 activity is markedly enhanced by thrombin- PAR1 interactions. A combination of bivalirudin ( hirulog) plus a novel PAR4 pepducin antagonist, P4pal-i1, effectively inhibited aggregation of human platelets to even high concentrations of thrombin and prevented occlusion of carotid arteries in guinea pigs. Likewise, combined inhibition of PAR1 and PAR4 with small-molecule antagonists and pepducins was effective against carotid artery occlusion. Coimmunoprecipitation and fluorescence resonance energy transfer studies revealed that PAR1 and PAR4 associate as a heterodimeric complex in human platelets and fibroblasts. PAR1-PAR4 cofactoring was shown by acceleration of thrombin cleavage and signaling of PAR4 on coexpression with PAR1.Conclusions - We show that PAR1 and PAR4 form a stable heterodimer that enables thrombin to act as a bivalent functional agonist. These studies suggest that targeting the PAR1-PAR4 complex may present a novel therapeutic opportunity to prevent arterial thrombosis.