Differential Roles of the NADPH-Oxidase 1 and 2 in Platelet Activation and Thrombosis.
Differential Roles of the NADPH-Oxidase 1 and 2 in Platelet Activation and Thrombosis.
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DOI：
10.1161/atvbaha.116.307308
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发表时间：
2016-05
期刊：
影响因子：
--
通讯作者：
Du X
中科院分区：
文献类型：
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作者：
Delaney MK;Kim K;Estevez B;Xu Z;Stojanovic-Terpo A;Shen B;Ushio-Fukai M;Cho J;Du X
已知活性氧（ROS）调节血小板活化;然而，在血小板活化期间ROS产生的机制仍不清楚。血小板表达烟酰胺腺嘌呤二核苷酸（磷酸）（NAD（P）H）氧化酶（NOX）的不同亚型。在这里，我们研究了NOX 1和NOX 2在ROS产生和血小板活化中的作用，使用NOX 1和NOX 2敲除小鼠。NOX 1 −/Y血小板在凝血酶和血栓烷A2类似物U46619诱导的G蛋白偶联受体（GPCR）介导的血小板活化中表现出选择性缺陷，但在胶原相关肽（CRP）（一种糖蛋白VI（GPVI）激动剂）诱导的血小板活化中不受影响。相反，NOX 2 −/−血小板显示出对CRP诱导的血小板活化的有效抑制，并且还显示出对凝血酶诱导的血小板活化的部分抑制。一致的是，在用凝血酶刺激的NOX 1 −/Y血小板中，ROS的产生受到抑制，而不是CRP，而NOX 2 −/−血小板显示出由CRP或凝血酶诱导的ROS产生减少。NOX 1/2缺陷型血小板中ROS生成减少与Syk和磷脂酶Cγ2（PLCγ2）活化受损相关，但对丝裂原活化蛋白激酶途径的影响最小。有趣的是，在NOX 2-/-小鼠中，激光诱导的动脉血栓形成受到损害，但出血时间没有受到影响。注射NOX 2-/-血小板的WT血小板减少小鼠也显示出动脉血栓形成缺陷，表明血小板NOX 2在体内血栓形成中发挥重要作用，但不止血。NOX 1和NOX 2在不同的血小板活化途径和血栓形成中发挥不同的作用。这些酶产生的ROS通过Syk/PLCγ/钙信号通路促进血小板活化。
Reactive oxygen species (ROS) are known to regulate platelet activation; however, the mechanisms of ROS production during platelet activation remain unclear. Platelets express different isoforms of nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) oxidases (NOXs). Here we investigated the role of NOX1 and NOX2 in ROS generation and platelet activation using NOX1 and NOX2 knockout mice. NOX1−/Y platelets showed selective defects in G protein-coupled receptor (GPCR)-mediated platelet activation induced by thrombin and thromboxane A2 analog U46619, but were not affected in platelet activation induced by collagen-related peptide (CRP), a glycoprotein VI (GPVI) agonist. In contrast, NOX2−/− platelets showed potent inhibition of CRP-induced platelet activation, and also showed partial inhibition of thrombin-induced platelet activation. Consistently, production of ROS was inhibited in NOX1−/Y platelets stimulated with thrombin, but not CRP, whereas NOX2−/− platelets showed reduced ROS generation induced by CRP or thrombin. Reduced ROS generation in NOX1/2 deficient platelets is associated with impaired activation of Syk and phospholipase Cγ2 (PLCγ2), but minimally affected mitogen-activated protein kinase pathways. Interestingly, laser-induced arterial thrombosis was impaired but the bleeding time was not affected in NOX2−/− mice. WT thrombocytopenic mice injected with NOX2−/− platelets also showed defective arterial thrombosis, suggesting an important role for platelet NOX2 in thrombosis in vivo but not hemostasis. NOX1 and NOX2 play differential roles in different platelet activation pathways and in thrombosis. ROS generated by these enzymes promotes platelet activation via the Syk/PLCγ/calcium signaling pathway.