a Department of Cardiovascular Sciences , University of Leicester and NIHR Cardiovascular Biomedical Research Unit, Glenfield Hospital , Leicester , UK.
b College of Applied Medical Sciences , Qassim University , KSA.
Platelets. 2018 Jul;29(5):446-454. doi: 10.1080/09537104.2017.1332366. Epub 2017 Jul 20.
On activation platelets release microRNAs and extracellular vesicles (EV) into circulation. The release of EV from platelets has been shown to be dependent on the agonist; in this study, we investigated whether the microRNA profile or EV released from platelets was also agonist specific. Washed platelets from healthy subjects were maximally stimulated with agonists specific for the receptors for collagen (Glycoprotein VI (GPVI)), thrombin (PAR1/PAR4), or ADP (P2Y1/P2Y12) with/without inhibiting secondary mediators, using aspirin to block cyclooxygenase-1 and apyrase to remove ADP. The released microRNAs were profiled using TaqMan microRNA microarray cards. Platelet-derived EV (pdEV) were characterized by size (Nanoparticle Tracking Analysis, NTA), for procoagulant activity (Annexin-V binding and support of thrombin generation), and for the EV markers CD63 and HSP70. Platelet activation triggered the release of 57-79 different microRNAs, dependent upon agonist, with a core of 46 microRNAs observed with all agonists. There was a high level of correlation between agonists (r > 0.98; p < 0.0001 for all), and with the microRNA content of the parent platelets (r > 0.98; p < 0.0001). The 46 microRNAs seen in all samples are predicted to have significant effects on the translation of proteins involved in endocytosis, cell cycle control, and differentiation. MiR-223-3p was the most abundant in all samples and has previously been implicated in myeloid lineage development and demonstrated to have anti-inflammatory effects. Stimulation through GPVI produced a pdEV population with significantly more procoagulant activity than the other agonists. Apyrase significantly reduced microRNA and pdEV release, while aspirin had little effect. These data suggest that all tested agonists trigger the release of a similar microRNA profile while the procoagulant activity of the pdEV was agonist dependent. ADP was shown to play an important role in the release of both microRNAs and pdEV.
血小板激活后会将 microRNA 和细胞外囊泡（EV）释放到循环中。已有研究表明，血小板释放 EV 依赖于激动剂；在本研究中，我们探讨了血小板释放的 microRNA 谱或 EV 是否也具有激动剂特异性。使用特异性针对胶原蛋白受体（糖蛋白 VI（GPVI））、凝血酶（PAR1/PAR4）或 ADP（P2Y1/P2Y12）的激动剂对来自健康受试者的洗涤血小板进行最大刺激，并用阿司匹林阻断环氧化酶-1 并用 apyrase 去除 ADP。使用 TaqMan microRNA 微阵列卡对释放的 microRNA 进行分析。通过大小（纳米颗粒跟踪分析，NTA）、促凝活性（膜联蛋白-V 结合和支持凝血酶生成）以及 EV 标志物 CD63 和 HSP70 对血小板衍生的 EV（pdEV）进行表征。血小板激活触发了 57-79 种不同的 microRNA 的释放，这取决于激动剂，并且所有激动剂均观察到了 46 种核心 microRNA。激动剂之间具有高度相关性（r>0.98；p<0.0001），与亲本血小板的 microRNA 含量之间具有高度相关性（r>0.98；p<0.0001）。在所有样本中均可见的 46 种 microRNA 预计对参与胞吞作用、细胞周期控制和分化的蛋白质的翻译具有重要影响。所有样本中 miR-223-3p 最为丰富，先前已被牵连到髓系发育，并被证明具有抗炎作用。通过 GPVI 刺激产生的 pdEV 群体具有比其他激动剂明显更高的促凝活性。Apyrase 显著减少了 microRNA 和 pdEV 的释放，而阿司匹林几乎没有影响。这些数据表明，所有测试的激动剂均触发了相似的 microRNA 谱的释放，而 pdEV 的促凝活性则取决于激动剂。ADP 被证明在 microRNA 和 pdEV 的释放中均起重要作用。
