基于HO-1和NF-κB信号通路探究穿心莲内酯及其衍生物抑制PRRSV的作用机制

At present, porcine reproductive and respiratory syndrome (PRRS) represents one of the most harmful pandemics in Chinese pig industry, which is induced by porcine reproductive and respiratory syndrome virus (PRRSV) and the positive rate of PRRSV throughout Chinese pig farms reaches up to 54%. Currently, the most prevalent strategy for PRRSV control remains vaccination, however it has little efficiency. Thus the development of antiviral agents against PRRSV is urgently needed. The large aggregation of studies has shown that the enhancement of HO-1 signaling pathway and the inhibition on activation of NF-κB signaling pathway induced by PRRSV infections not only reduce the production of pro-inflammatory cytokines and the recruitment of inflammatory cells but also inhibit the replication of progeny viruses. Hence, HO-1 and NF-κB signaling pathways become promising targets for developing novel antivirals against PRRSV infections. Andrographolide (Andro) and several hydrosoluble salts derived from Andro have been used to treat respiratory infectious diseases in human being clinic for decades in China. It has been verified by several studies that Andro could intervene the replication of pathogens including viruses by enhancing HO-1 pathway and inhibiting NF-κB pathway. In preliminary studies, we have shown that Andro could significantly inhibit the replication of PRRSV in Marc-145 and PAMs cells. Based on the previous studies, this project will focus on getting more Andro derivatives by chemical synthesis under the guidance of the antiviral structure-activity relationship, and obtaining novel derivatives with higher antiviral activity. Furthermore, we will also focus on exploration of the underlying mechanism of action based on HO-1 and NF-κB signaling pathways. Our study will provide the scientific basis for the development of novel anti-PRRSV lead compounds with high efficiacy, low toxicity and broad antiviral spectrum.

猪繁殖与呼吸综合征病毒（PRRSV）在我国猪场的检出率高达54%，PRRS已成为对我国养猪业危害最大的病毒感染性疫病。目前主要应用疫苗免疫预防PRRS，但效果较差，抗PRRSV药物的研发刻不容缓。大量研究表明，激活HO-1通路和抑制NF-κB通路不仅显著减少炎症因子及炎症细胞的产生，而且抑制PRRSV的复制，因此HO-1和NF-κB通路成为极具前景的抗PRRSV药物靶标。穿心莲内酯（Andro）及其多种水溶性盐在人医临床上已被广泛用于治疗呼吸道感染。多篇文献报道，Andro可通过激活HO-1通路和抑制NF-κB通路干预病毒等病原的感染。前期我们发现，Andro在细胞上显著抑制PRRSV的增殖。本项目拟在构效关系指导下合成更多Andro衍生物，获得抗PRRSV活性更好的单体，并基于其对HO-1和NF-κB通路的影响探究其作用机制，为研究和开发高效广谱的抗PRRSV药物提供科学依据。

猪繁殖与呼吸综合征病毒（PRRSV）在我国猪场的检出率高达54%，据估算，PRRS导致的猪存活率和生产性能的下降使我国养猪业每年损失逾千亿元，已成为对我国养猪业危害最大的病毒感染性疾病。目前主要应用疫苗预防PRRS，但效果较差，抗PRRSV药物的研发刻不容缓。本项目基于课题组前期发现穿心莲内酯等多个药物/化合物在细胞中对PRRSV具有显著抑制作用，对这些活性化合物的抗PRRSV活性及其作用机制进行深入系统的研究，为抗PRRSV药物的发现提供科学依据。获得的主要研究成果包括以下三个方面：(1) 合成了系列穿心莲内酯(Andro)衍生物，初步阐明了Andro及其衍生物抑制PRRSV的构效关系，揭示了Andro及其衍生物“穿琥宁”抑制PRRSV的作用机制。研究结果解析了中药穿心莲及其复方制剂临床上用于防治畜禽病毒感染性疾病的药效物质基础，并为Andro和PDS用于防治猪PRRSV感染提供了实验依据。(2) 发现抗疟药物青蒿琥酯具有显著抗PRRSV活性，其有效抑制浓度低至2µM，揭示了其通过激活AMPK/Nrf2/HO-1信号通路抑制PRRSV的作用机制，该通路可能成为抗病毒药物研究的新靶标。该研究为青蒿素类药物在兽医临床上可能用于PRRS的防治提供了科学依据。(3) 发现川楝素具有显著抗PRRSV活性，其有效浓度低至nM水平，揭示其通过激活IFI16/Casepase-1/IL-1β通路发挥抗PRRSV活性的作用机制，该通路是潜在的抗PRRSV药物靶点，研究结果为临床应用川楝素治疗PRRS提供了实验依据。. 本项目成果在Journal of Virology、Veterinary Research等国际病毒学和兽医学经典期刊发表论文共4篇，申报国家发明专利2项，另有1项有关抗PRRSV药物研究的专利获得授权。此外，项目培养毕业博士研究生2名，毕业硕士研究生3名。项目的实施及取得的成果有效地促进我国抗PRRSV的新药研发及其临床应用的进程。