Abstract：
OBJECTIVE: MicroRNA-126 (miR-126), one of the most abundant microRNAs in platelets, is involved in the regulation of platelet activity and the circulating miR-126 is reduced during antiplatelet therapy. However, whether intraplatelet miR-126 plays a role in thrombosis and platelet inhibition remains unclear.
RESULTS: Here, using tissue-specific knockout mice, we reported that the deficiency of miR-126 in platelets and vascular endothelial cells significantly prevented thrombosis and prolonged bleeding time. Using chimeric mice, we identified that the lack of intraplatelet miR-126 significantly prevented thrombosis. Ex vivo experiments further demonstrated that miR-126-deficient platelets displayed impaired platelet aggregation, spreading and secretory functions. Next, miR-126 was confirmed to target phosphoinositol-3 kinase regulatory subunit 2 (PIK3R2) in platelet, which encodes a negative regulator of the PI3 K/AKT pathway, enhancing platelet activation through activating the integrin αIIbβ3-mediated outside-in signaling. After undergoing myocardial infarction (MI), chimeric mice lacking intraplatelet miR-126 displayed reduced microvascular obstruction and prevented MI expansion in vivo. In contrast, overexpression of miR-126 by the administration of miR-126 agonist (agomiR-126) in wild-type mice aggravated microvascular obstruction and promoted MI expansion, which can be almost abolished by aspirin administration. In patients with cardiovascular diseases, antiplatelet therapies, either aspirin alone or combined with clopidogrel, decreased the level of intraplatelet miR-126. The reduction of intraplatelet miR-126 level was associated with the decrease of platelet activity.
CONCLUSIONS: Our murine and human data reveal that (i) intraplatelet miR-126 contributes to platelet activity and promotes thrombus formation, and (ii) the reduction of intraplatelet miR-126 contributes to platelet inhibition during antiplatelet therapy.
RESULTS: Here, using tissue-specific knockout mice, we reported that the deficiency of miR-126 in platelets and vascular endothelial cells significantly prevented thrombosis and prolonged bleeding time. Using chimeric mice, we identified that the lack of intraplatelet miR-126 significantly prevented thrombosis. Ex vivo experiments further demonstrated that miR-126-deficient platelets displayed impaired platelet aggregation, spreading and secretory functions. Next, miR-126 was confirmed to target phosphoinositol-3 kinase regulatory subunit 2 (PIK3R2) in platelet, which encodes a negative regulator of the PI3 K/AKT pathway, enhancing platelet activation through activating the integrin αIIbβ3-mediated outside-in signaling. After undergoing myocardial infarction (MI), chimeric mice lacking intraplatelet miR-126 displayed reduced microvascular obstruction and prevented MI expansion in vivo. In contrast, overexpression of miR-126 by the administration of miR-126 agonist (agomiR-126) in wild-type mice aggravated microvascular obstruction and promoted MI expansion, which can be almost abolished by aspirin administration. In patients with cardiovascular diseases, antiplatelet therapies, either aspirin alone or combined with clopidogrel, decreased the level of intraplatelet miR-126. The reduction of intraplatelet miR-126 level was associated with the decrease of platelet activity.
CONCLUSIONS: Our murine and human data reveal that (i) intraplatelet miR-126 contributes to platelet activity and promotes thrombus formation, and (ii) the reduction of intraplatelet miR-126 contributes to platelet inhibition during antiplatelet therapy.
摘要：
目的：微小RNA-126（miR-126），血小板中最丰富的microRNAs之一，参与血小板活性的调节，循环miR-126在抗血小板治疗期间减少。然而,血小板内miR-126是否在血栓形成和血小板抑制中起作用尚不清楚.
结果：这里，使用组织特异性敲除小鼠，我们报道,miR-126在血小板和血管内皮细胞中的缺乏可显著阻止血栓形成和延长出血时间.使用嵌合小鼠，我们发现,缺乏血小板内miR-126可显著预防血栓形成.离体实验进一步证明，缺乏miR-126的血小板显示受损的血小板聚集，传播和分泌功能。接下来,miR-126被证实靶向血小板中的磷酸肌醇-3激酶调节亚基2(PIK3R2),它编码PI3K/AKT通路的负调节因子，通过激活整合素αIIbβ3介导的外内信号增强血小板活化。在经历心肌梗死（MI）后，缺乏血小板内miR-126的嵌合小鼠在体内显示出减少的微血管阻塞和阻止MI扩张.相比之下,通过在野生型小鼠中施用miR-126激动剂（agomiR-126）过表达miR-126加重了微血管阻塞并促进了MI扩张，阿司匹林几乎可以废除。在心血管疾病患者中，抗血小板治疗,阿司匹林单独或联合氯吡格雷，降低血小板内miR-126的水平。血小板内miR-126水平的降低与血小板活性的降低有关。
结论：我们的小鼠和人类数据表明（i）血小板内miR-126有助于血小板活性并促进血栓形成，和（ii）血小板内miR-126的减少有助于抗血小板治疗期间的血小板抑制。
结果：这里，使用组织特异性敲除小鼠，我们报道,miR-126在血小板和血管内皮细胞中的缺乏可显著阻止血栓形成和延长出血时间.使用嵌合小鼠，我们发现,缺乏血小板内miR-126可显著预防血栓形成.离体实验进一步证明，缺乏miR-126的血小板显示受损的血小板聚集，传播和分泌功能。接下来,miR-126被证实靶向血小板中的磷酸肌醇-3激酶调节亚基2(PIK3R2),它编码PI3K/AKT通路的负调节因子，通过激活整合素αIIbβ3介导的外内信号增强血小板活化。在经历心肌梗死（MI）后，缺乏血小板内miR-126的嵌合小鼠在体内显示出减少的微血管阻塞和阻止MI扩张.相比之下,通过在野生型小鼠中施用miR-126激动剂（agomiR-126）过表达miR-126加重了微血管阻塞并促进了MI扩张，阿司匹林几乎可以废除。在心血管疾病患者中，抗血小板治疗,阿司匹林单独或联合氯吡格雷，降低血小板内miR-126的水平。血小板内miR-126水平的降低与血小板活性的降低有关。
结论：我们的小鼠和人类数据表明（i）血小板内miR-126有助于血小板活性并促进血栓形成，和（ii）血小板内miR-126的减少有助于抗血小板治疗期间的血小板抑制。
