不饱和脂肪酸调控狂犬病毒和乙脑病毒感染与免疫的分子机制

Rabies virus (RV) and Japanese encephalitis virus (JEV) are major causative agents of zoonosis. The first step of these virus entering into host are fighting with host immune system. However, when the host immune system was downregulated, the virus infection would upregulate and the vaccine immune would be abortive. Recently, some researchers have reported that dietary omega-3 fatty acids (ω-3) depress immune cell activation and impair the immune response against bacterial pathogens infection, but the ω-3 could affect virus infection which has not been study. In the recent study, the applicant found that the dendritic cells (DCs) of ω-3 over expressing will have low immune sensitization and poor virus control. Therefore, the hypothesis is ω-3 plays a key role in regulating the immune evasion of RV and JEV. To demonstrate that, we use DCs in vitro culture system, flow cytometry and western blot to study the receptor of ω-3 through TAK1 kinase depressing MKK4 and IkappaB to regulate DCs activation, which affect DCs infections immunity of RV and JEV. Further, in vivo research to study the survival rate of mouse challenge with wild type RV and JEV after ω-3 treatment, or the immune response of mouse vaccinated with lab attenuated RV and JEV after ω-3 treatment. This present study 1st time show ω-3 induce immune suppression to reduce host defending viral infection, which will provide a novel stratagem to compete with RV and JEV infection.

狂犬病毒（RV）和乙型脑炎病毒（JEV）是当前严重危害人畜健康的病原。病毒与免疫系统相互博弈是病毒入侵的第一步，当宿主免疫力下降时，不仅增加病毒感染机体的可能，也降低了疫苗免疫原性导致免疫失败。研究发现，日常治疗慢性炎症的不饱和脂肪酸（ω-3），不仅抑制免疫细胞激活和炎症反应，而且降低宿主对细菌性病原的抵抗能力。申请人发现ω-3过表达抑制树突状细胞（DCs）的激活和DCs的抗病毒反应，我们推测ω-3在RV和JEV致病和免疫逃避中扮演重要角色。为证实以上假设，通过培养DCs，流式细胞术和蛋白印迹等技术，研究ω-3受体GPR120通过TAK1影响下游MKK4和IkappaB，并对DCs抗RV和JEV感染能力的影响。用小鼠模型分别检测ω-3对RV和JEV致死率的影响及ω-3对RV和JEV疫苗免疫效果的影响。本项目首次研究过量ω-3导致免疫抑制从而降低抗病毒免疫反应，为RV和JEV防治提供新思路。

狂犬病毒（RV）和乙脑病毒（JEV）是严重危害公共健康的人畜共患传染病，均没有可靠的治疗手段，因此提高疫苗保护效果及优化疫苗免疫程序尤为重要。树突状细胞（DC）是功能最强大的抗原提呈细胞，疫苗注射后高效激活DC能够提高疫苗的保护效果。当宿主免疫力低下或免疫系统受到抑制，均会导致疫苗免疫失败。有临床病例报道大量服用奥米茄-3不饱和脂肪酸（ω-3）促进结核病的感染几率，并且我们前期结果表明过量的ω-3使小鼠对RV和JEV更易感。ω-3有显著的抗炎抗氧化应激的作用，通过游离脂肪酸受体（FFAR）激活下游β-arr2抑制炎症因子转录。本项目以ω-3和FFAR为切入点，研究了证明了不论是过量补充DHA还是抑制GPR120的表达均会破坏TH17和Treg的平衡；DC通过调整自身GPR120的表达并通过ω-3调整DC的静息与激活状态。以上研究为治疗自身免疫性疾病和研发疫苗佐剂提供了靶位点和科学依据。