血小板活化在川崎病血管炎性损伤中的新机制——血小板微颗粒中miR-21-5p的作用

Kawasaki disease (KD) is a systemic immune vasculitis, and is considered the high risk factor for adult coronary heart disease. However, the mechanism of immune vasculitis in KD is not yet clear. Our preliminary studies showed that the platelet microparticles (PMPs) derived by activated platelet were closely related to coronary artery lesions in KD. Further studies showed that miRNAs packaged in PMPs may play a role in immune vasculitis in KD. The results of Affymetrix microRNA chip and real-time quantitative PCR indicated that miR-21-5p expression was higher in PMPs. Software predicted that the functions of target genes (DDAH1 and OLR1) were related to immune vasculitis. Therefore, we speculated that miR-21-5p in PMPs may play a role in immune vasculitis by regulating target gene (DDAH1 or OLR1). With cell biology and molecular biology experiments, we intend to explore the following: whether PMPs promote immune vasculitis by miR-21-5p, whether DDAH1 or OLR1 is the functional target gene of miR-21-5p in KD, and whether targeting miR-21-5p is an effective treatment in KD. The success of this study will provide a new explanation for the mechanism of immune vasculitis and a new strategy of the treatment in KD.

川崎病(Kawasaki disease KD)是全身免疫性血管炎性疾病，是成年后冠心病的高危因素，但其血管炎症发生发展的机制尚不甚清楚。我们预实验结果显示血小板活化产生的PMPs与KD冠脉损伤紧密相关，进一步研究发现PMPs可能通过包裹的miRNAs发挥作用。芯片和RT-qRCR结果提示miR-21-5p在KD的PMPs中表达量较高，软件预测提示其靶基因（DDAH1/OLR1）功能与血管炎症相关。由此我们认为PMPs可能通过其包裹的miR-21-5p调控靶基因（DDAH1/OLR1）参与KD血管炎性损伤。本课题拟通过细胞和分子生物学实验进一步证明PMPs是否通过miR-21-5p促进血管炎症；在KD中靶基因（DDAH1/OLR1）是否是miR-21-5p的功能性靶基因；靶向miR-21-5p是否对KD治疗有效。本研究的成功将为KD血管炎性损伤机制提供新的解释，为KD治疗提出新的策略。

川崎病（Kawasaki Disease, KD）是全身免疫性血管炎性疾病，是成年后冠心病的高危因素，但是其血管炎症的发生发展机制尚不甚清楚。本课题组前期研究发现KD外周血中的微颗粒与血管内皮功能障碍密切有关，血小板微颗粒中包含的miR-21-5p可能参与了KD血管炎症反应。外泌体是血清中常见一种微颗粒，直径约0.03~0.15μm，携带蛋白及miRNAs等，参与细胞间信息的传递。本研究在此基础上发现，KD血清外泌体携带多种miRNAs，其中miR-21-5p在KD血清外泌体中表达量较高，预测其靶基因为DDAH1。临床研究发现KD血清外泌体中miR-21-5p的相关表达量在KD急性期及亚急性期升高，尤其是在亚急性期明显升高，而血清中NO浓度降低、TNF-α浓度升高；并运用细胞模型和动物模型验证miR-21-5p对DDAH1的抑制作用。由此我们认为KD血清外泌体通过其包裹的miR-21-5p调控靶基因（DDAH1）参与KD血管炎性损伤。本研究为KD血管炎性损伤机制提供新的解释，为KD治疗提出新的策略。