The ABCC4 membrane transporter modulates platelet aggregation
The ABCC4 membrane transporter modulates platelet aggregation
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DOI：
10.1182/blood-2014-08-595942
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发表时间：
2015-11-12
期刊：
影响因子：
20.3
通讯作者：
Schuetz, John D.
中科院分区：
文献类型：
--
作者：
Cheepala, Satish B.;Pitre, Aaron;Schuetz, John D.
控制血小板的活化是减轻心血管疾病的关键策略。以前的研究表明，ATP结合盒（ABC）转运蛋白，ABCC4，血小板致密颗粒的功能。使用质膜生物素化和超分辨率显微镜，我们证明ABCC 4主要表达在小鼠和人血小板的质膜上。缺乏ABCC4的血小板具有不变的致密颗粒功能、数量和体积，但在胶原诱导的聚集中具有选择性损伤。因此，Abcc4敲除（KO）血小板附着到胶原基质也是错误的，并与细胞内环AMP（cAMP）升高和主要胶原受体GPVI的质膜定位降低有关。在氯化铁血管损伤模型中，Abcc4 KO小鼠表现出明显受损的血栓形成。磷酸二酯酶抑制剂EHNA（一种非ABCC4底物）与ABCC4缺陷结合时，血小板聚集的衰减说明了磷酸二酯酶和ABCC4之间的重要功能相互作用。这在体内延长，其中EHNA显著延长出血时间，但仅在Abcc4 KO小鼠中。此外，我们在人血小板中证明，ABCC4抑制，当与磷酸二酯酶抑制相结合时，强烈损害血小板聚集。这些发现具有重要的临床意义，因为它们直接突出了ABCC 4转运蛋白功能和磷酸二酯酶在解释抗血栓药物的cAMP导向活性方面的重要关系。
Controlling the activation of platelets is a key strategy to mitigate cardiovascular disease. Previous studies have suggested that the ATP-binding cassette (ABC) transporter, ABCC4, functions in platelet-dense granules. Using plasma membrane biotinylation and super-resolution microscopy, we demonstrate that ABCC4 is primarily expressed on the plasma membrane of both mouse and human platelets. Platelets lacking ABCC4 have unchanged dense-granule function, number, and volume, but harbor a selective impairment in collagen-induced aggregation. Accordingly, Abcc4 knockout (KO) platelet attachment to a collagen substratum was also faulty and associated with elevated intracellular cyclic AMP (cAMP) and reduced plasma membrane localization of the major collagen receptor, GPVI. In the ferric-chloride vasculature injury model, Abcc4 KO mice exhibited markedly impaired thrombus formation. The attenuation of platelet aggregation by the phosphodiesterase inhibitor EHNA (a non-ABCC4 substrate), when combined with Abcc4 deficiency, illustrated a crucial functional interaction between phosphodiesterases and ABCC4. This was extended in vivo where EHNA dramatically prolonged the bleeding time, but only in Abcc4 KO mice. Further, we demonstrated in human platelets that ABCC4 inhibition, when coupled with phosphodiesterase inhibition, strongly impaired platelet aggregation. These findings have important clinical implications because they directly highlight an important relationship between ABCC4 transporter function and phosphodiesterases in accounting for the cAMP-directed activity of antithrombotic agents.