白杨素干预中性粒细胞介导的川崎病血管损伤的机制研究

Kawasaki disease (KD), which is characterized by vasculitis, is a high risk factor of acquired heart disease in children. Neutrophils activation in acute KD participates in the process of KD immune vasculitis. NFAT activation is involved in neutrophils activation and KD vasculitis. Chrysin has recently attracted the attention for its anti-inflammatory property. Our preliminary experiment have showed that chrysin inhibits NFAT2 dephosphorylation activation and promotes neutrophils apoptosis on activated neutrophils, and decreases inflammatory factor TNF-α level in peripheral blood of KD mice. The results from docking stimulation showed that chrysin was potentially compatible with PLCγ1, calmodulin(CaM) and calcineurin, the upstream genes of NFAT2. Therefore, we proposed that chrysin inhibits neutrophil-mediated inflammatory response by regulating PLCγ1/CaM/calcineurin signaling pathway, reducing vascular endothelial injury in KD. The contents of study include: ① Studying effects of chrysin on inflammatory response of endothelial vessels in KD mice; ② Studying effects of chrysin on neutrophils activation and apoptosis in vitro; ③ Confirming the targets of chrysin to NFAT2 pathway. Through these efforts, we consider that the research is a kind of original design that can provide new insights on anti-inflammatory effects of the dietary phytochemical chrysin, and provides experimental basis for treatment of KD.

以血管炎为特征的川崎病(Kawasaki disease，KD)是儿童成年后冠心病的高危因素。KD急性期中性粒细胞活化，参与血管炎进程。NFAT通路激活与中性粒细胞活化、KD血管炎相关。白杨素具有明显抗炎作用，前期研究显示白杨素抑制NFAT2激活，诱导活化的中性粒细胞凋亡，降低KD小鼠外周血TNF-α水平。分子对接提示，白杨素可能与NFAT2通路上游关键分子PLCγ1、Calmodulin(CaM)、Calcineurin有亲和性结合。我们设想：白杨素作用于PLCγ1/CaM/calcineurin通路抑制NFAT2激活，诱导中性粒细胞凋亡，减少炎症因子释放，改善KD血管炎性病变。本研究拟探讨：①动物水平验证白杨素对KD血管损伤的影响；②白杨素对中性粒细胞活化的影响；③明确白杨素对NFAT2通路的直接作用靶点。研究具有源头创新性，拓展膳食化合物白杨素抗炎新思路，为KD抗炎治疗提供实验基础。

以全身性血管炎性改变为特征的川崎病，是成年后冠心病的高危因素。川崎病急性期炎症因子爆发，引起全身炎症反应，外周血中炎性细胞活化，浸润血管内皮，导致血管内皮功能紊乱。本项目通过天然来源的白杨素，干预课题组前期筛选的在川崎病血管损伤中发挥重要作用的NFAT2及上游信号通路，探索白杨素在川崎病中的抗免疫性炎症作用的分子机制，明确其可能的作用靶点。运用白色念珠菌细胞壁提取物构建的血管炎小鼠模型，体内的实验结果证实，白杨素可以降低川崎病小鼠模型急性期炎症因子表达水平，改善川崎病心脏冠状动脉血管的炎性改变以及弹力纤维改变。运用TNF-刺激构建的冠状动脉血管内皮细胞损伤模型，体外的实验结果证实，白杨素可改善TNF-刺激引起的冠状动脉内皮细胞细胞因子IL-6、IL-8、IL-23，和粘附因子ICAM、VCAM表达水平增高，通过运用PLCγ1抑制剂，进一步证实白杨素对血管内皮细胞的刺激作用是通过PLCγ1/NFAT2通路引起。本项目开辟了膳食化合物白杨素发挥抗炎作用的新思路，为川崎病的抗炎治疗提供新的理论基础。本研究强调了NFAT通路在川崎病的发病机制中的重要性，并阐明以白杨素作为天然来源的免疫抑制药物作为治疗策略的可能性。