异绿原酸A通过PERK信号通路缓解小反刍兽疫病毒诱导的内质网应激

Isochlorogenic acid A alleviates reticulum stress induced by peste des petits ruminants virus via PERK signaling pathway

病毒感染可诱导宿主细胞产生内质网应激(ERS)与未折叠蛋白反应(UPR),导致内质网稳态失衡。为了探讨异绿原酸A(IAA)在调节小反刍兽疫病毒(PPRV)诱导的ERS和UPR中的作用机制,采用MTT试验、间接免疫荧光试验和Western blot评估IAA的抗PPRV活性;采用Western blot和实时荧光定量PCR观察IAA对PPRV诱导的ERS及PERK信号通路的影响。结果表明,IAA能显著抑制PPRV在LDG-2细胞中的复制及病毒诱导的细胞病变,显著提高病毒感染细胞的存活率;与病毒对照组相比,IAA处理的PPRV感染细胞中GRP78和PPRV表达水平、p-PERK/PERK和p-eIF2α/eIF2α比值均显著降低;GADD153表达水平则在病毒感染24、36h显著降低,在48、60h显著升高。用4-PBA阻断PPRV诱导的ERS,IAA和4-PBA+IAA处理PPRV感染细胞中GRP78、PPRV-N蛋白、GADD153的表达水平及p-eIF2α/eIF2α、p-PERK/PERK比值均显著降低。由此可见,IAA可通过抑制PERKeIF2α-GADD153信号通路的激活缓解PPRV感染诱导的ERS,从而抑制病毒在宿主细胞的复制。

Viral infection can induce endoplasmic reticulum stress(ERS)and unfolded protein response(UPR)in host cells,resulting in perturbation of endoplasmic reticulum homeostasis.To elucidate the action mechanism of isochlorogenic acid A(IAA)in regulating peste des petits ruminant virus(PPRV)-induced ERS and UPR,MTT assay,indirect immunofluorescence assay and Western blot were used to evaluate the anti-PPRV activity of IAA,and the effects of IAA on PPRV-induced ERS and PERK signaling pathway were studied by Western blot and quantitative real-time PCR.The results showed that the PPRV replication and virus-induced cytopathic in LDG-2cells were significantly inhibited,and the survival rate of virus-infected cells was significantly increased due to IAA treatment.Compared with the virus control group,the expression levels of GRP78and p-eIF2α,the ratios of p-PERK/PERK and p-eIF2α/eIF2αin IAA treated PPRV-infected cells were significantly decreased.The expression level of GADD153significantly decreased at 24,36h,and significantly increased at 48,60h.Furthermore,treatment with ERS inhibitor 4-PBA could significantly suppress the expression levels of GRP78,PPRV-N protein and GADD153in PPRV-infected cells,and the ratios of p-eIF2α/eIF2αand p-PERK/PERK in PPRV-infected cells were also significantly decreased caused by treatment with IAA or 4-PBA and IAA combination.These findings implicated that the PPRV-induced ERS could be alleviated by inhibiting activation of the PERK-eIF2α-GADD153signaling pathway,which led to restriction of PPRV replication in host cells.