基于天然免疫通路探索白头翁皂苷B4抗EV71病毒的作用机制

Enterovirus 71 (EV71) is the main etiological agent for outbreaks of hand foot and mouth disease (HFMD) affecting millions of people worldwide. However, no effective vaccine or antiviral drugs exist against EV71 infection. Pulsatilla chinensis (Bunge) Regel exhibits heatclearing, detoxification and insecticide activities. It is an essential medicine for the treatment of damp-heat and toxicity. Anemoside B4 is the major constituent of P. chinensis saponins. Previous studies have found that it can increase the survival rate of EV71-infected 3-day-old suckling mice from 52% to 90%, which is significantly better than the positive control drug ribavirin; it can significantly increase the survival rate of EV71-infected human rhabdomyosarcoma (RD) cells and reduce the expression of mRNA and protein levels of VP-1. We revealed that anemoside B4 could inhibit the innate immunity escape of EV71 through activating the innate immunity response. In this study, we will focus on clarification the antiviral mechanism, and find out the characteristics and advantages of anemoside B4 against EV71. This study would provide novel insights into the development of anemoside B4 as the potential therapeutic option against HFMD.

肠道病毒71型病毒(EV71)感染引起的手足口病(HFMD)患者易发展为重症和危重症，然而临床上缺乏特异性治疗药物及有效疫苗。白头翁具有清热解毒、凉血、杀虫止痢等功效，是治疗热毒血痢的要药；其中白头翁皂苷B4含量很高，为指标性化学成分。前期研究发现其可将EV71感染的3日龄乳鼠的存活率从52%上调到90%以上，显著优于阳性对照药物利巴韦林；能显著提高EV71感染的人横纹肌肉瘤（RD）细胞的存活率，明显降低病毒外壳蛋白VP-1 的mRNA及蛋白水平的表达。初步作用机制研究提示其能够通过激活天然免疫反应，抑制EV71的天然免疫逃逸作用。本课题拟进一步系统研究白头翁皂苷B4的抗EV71作用机制，发掘其抗EV71的作用特点及优势，为其作为极具潜力的手足口病治疗新药的开发研究提供科学依据。

肠道病毒71型病毒(EV71)感染引起的手足口病(HFMD)患者易发展为重症和危重症，然而临床上缺乏特异性治疗药物及有效疫苗。本课题研究发现白头翁皂苷B4具有明显的抗EV71感染活性，可将EV71感染的3日龄乳鼠的存活率从52%上调到90%以上；能显著提高EV71感染的人横纹肌肉瘤（RD）细胞的存活率，明显降低病毒外壳蛋白VP-1 的mRNA及蛋白水平的表达。作用机制研究表明，干扰细胞IFN-β表达，能够明显抑制白头翁皂苷B4抗病毒药效。通过基于SILAC的蛋白质组学分析，发现Hippo通路是影响白头翁皂苷B4抗病毒药效的重要通路，白头翁皂苷B4通过上调14-3-3蛋白，抑制yes相关蛋白(YAP)和干扰素调节因子3 (IRF3)之间的相互作用，激活维甲酸诱导基因I (RIG-I)样受体(RLRs)通路，增强IFN反应。进一步通过生物素-亲和素串联质谱分析发现白头翁皂苷B4能够与UFM1结合，增强MAVS信号体的UFM1修饰作用，激活天然免疫应答。本课题在发现白头翁皂苷B4治疗手足口病有效性的基础上，进一步阐释了其激活天然免疫通路独特的作用机制，为其临床应用提供了科学依据。