神经介素B(NMB)及其G蛋白偶联受体(NMBR)发挥的抗甲型流感病毒免疫反应,以及甲型流感病毒感染诱导细胞程序性死亡配体 1(PD-L1)高表达均与NF-κB信号通路有直接关系,而NF-κB信号通路的激活受ERK信号通路的调控.为深入探究NMB与NMBR调节H9N2 亚型流感病毒感染诱导PD-L1 上的作用,本研究以H9N2 亚型流感病毒为模式毒株,基于NMBR干扰和过表达细胞系、PD-L1 干扰和过表达细胞系以及C57BL/6 小鼠,采用RT-PCR和Western blot方法分析NMB与NMBR对PD-L1 表达变化以及ERK磷酸化的影响.结果显示:H9N2 亚型流感病毒感染诱导的NMBR和PD-L1 表达之间存在着负调控的关系,外源性NMB可以有效激活小鼠体内NMBR的表达,进而抑制PD-L1 表达,NMB与NMBR也能影响H9N2 感染诱导的ERK磷酸化水平.综上,H9N2 亚型流感病毒感染诱导表达的NMB与NMBR通过ERK信号通路调节PD-L1 的表达而发挥抗流感病毒作用,将为深度剖析宿主-甲型流感病毒之间的互作关系提供新的科学依据.
The activation of NF-κB signaling is regulated by the ERK signaling pathway.The antiviral immune responses of NMB and NMBR and the high expression of PD-L1 induced by influenza A virus infection are directly related to the signaling pathway of NF-κB.To identify the association between NMB and NMBR and PD-L1 during influenza A virus infection,H9N2 subtype was used as a model strain in this study,The effect of NMB and NMBR on the expression of PD-L1 and the phosphorylation of ERK were analyzed by RT-PCR and West-ern-blotting based on the effects of NMBR interference and overexpression cell lines,PD-L1 interference and overexpression cell lines,and C57BL/6 mice.The results showed that the expression of NMBR and PD-L1 induced by H9N2 subtype infection had a positive correlation with the expression of PD-L1.Moreover,exogenous NMB could effectively activate the expression of NMBR and then inhibit the expression of PD-L1;and NMB and NMBR could also directly regulate the level of ERK phosphorylation induced by H9N2 subtype infection.These re-sults suggested that H9N2 subtype infection-induced NMB and NMBR exerted anti-influenza A virus immune response through ERK signa-ling pathway mediated PD-L1 expression.The results provided a theoretical basis for further understanding of host-influenza A virus interac-tions and a new way to screen novel anti-influenza drug targets.