辅酶Q10通过调控糖蛋白VI信号通路抑制血小板聚集和活化

目的 血小板过度活化在血栓以及动脉粥样硬化（AS）的发生发展中发挥重要的作用,糖蛋白VI （GPVI）是血小板表面重要的受体,在血管损伤处通过与胶原结合介导血小板活化参与血栓以及AS的形成。辅酶Q₁₀（CoQ₁₀）作为膳食补充剂通过抗炎、抗氧化等发挥预防心血管疾病的功能,尤其是抗AS作用。但是CoQ₁₀是否影响血小板功能尚未见报道, 因此本研究通过体外实验探讨CoQ₁₀对血小板活化的影响及其对GPVI信号通路调控作用。方法 用不同浓度CoQ₁₀ （0、1、10、100 μmol/L）与健康人纯化血小板在体外共同孵育50 min,采用血小板聚集仪测定胶原诱导的血小板聚集率;用流式细胞术测定血小板表面CD62P、CD63、α_IIbβ₃的活化和纤维蛋白原结合率（Fibrinogen binding）;用Western blot检测胶原诱导的血小板GPVI信号通路相关蛋白磷酸化水平。结果 CoQ₁₀可以显著降低胶原诱导的血小板聚集率,抑制血小板表面CD62P和CD63的表达,并能显著抑制α_IIbβ₃的活化以及降低Fibrinogen binding百分率。CoQ₁₀下调胶原诱导的GPVI信号通路中Syk、LAT、SLP76、PLCγ2以及PKC的磷酸化水平。结论 CoQ₁₀抑制胶原诱导的血小板活化可能是通过下调GPVI信号通路来实现。

Coenzyme Q10 inhibits platelet aggregation and activation involving regulation of platelet glycoprotein VI signaling pathway

Objective Platelet hyperreactivity plays an important role in thrombosis and atherosclerosis(AS). Glycoprotein VI (GPVI) is an important platelet surface receptor that mediates platelet activation by binding to collagen at the site of blood vessel injury and participates in the thrombus and AS. Coenzyme Q₁₀ (CoQ₁₀) acts as a dietary supplement that can protect against cardiovascular disease, especially AS. This effect involves in its properties of anti-inflammatory and anti-oxidation. However, the effects of CoQ₁₀ on platelet function and the underlying mechanisms have been poorly understood. This study intended to investigate the effect of CoQ₁₀ on platelet activation and its regulation of GPVI signaling pathway in vitro. Methods Human gel-filtered platelets were incubated with different concentrations of CoQ₁₀ (0, 1, 10 or 100 μmol/L) for 50 min. Platelet aggregation was stimulated by 2 μg/mL collagen and run in an aggregometer. Flow cytometry was used to determine the expression of CD62P and CD63 on platelet surface, α_IIbβ₃ activation and fibrinogen binding to the activated platelets; The effect of CoQ₁₀ on the phosphorylation of collagen-induced GPVI signaling-related proteins was determined by Western blotting. Results CoQ₁₀ significantly attenuated collagen-induced platelet aggregation. Moreover, CoQ₁₀ also inhibited the expression of CD62P and CD63 on the platelet surface, and reduced αIIbβ3 activation and fibrinogen binding to the activated platelets. Western blotting showed that CoQ₁₀ markedly down-regulated collagen-induced phosphorylation of Syk, LAT, SLP76, and PLCγ2 and PKC in vitro. Conclusion CoQ₁₀ inhibits collagen-induced platelet activation and aggregation possibly through down-regulating the GPVI signaling pathway.