Viral infection can induce endoplasmic reticulum stress(ERS)and unfolded protein re-sponse(UPR)in host cells,resulting in perturbation of endoplasmic reticulum homeostasis.To e-lucidate the action mechanism of isochlorogenic acid A(IAA)in regulating peste des petits rumi-nant 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-2 cells were significantly inhibited,and the survival rate of virus-infected cells was significantly in-creased due to IAA treatment.Compared with the virus control group,the expression levels of GRP78 and p-eIF2α,the ratios of p-PERK/PERK and p-eIF2α/eIF2α in IAA treated PPRV-infec-ted cells were significantly decreased.The expression level of GADD153 significantly decreased at 24,36 h,and significantly increased at 48,60 h.Furthermore,treatment with ERS inhibitor 4-PBA could significantly suppress the expression levels of GRP78,PPRV-N protein and GADD153 in PPRV-infected cells,and the ratios of p-eIF2α/eIF2α and 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-GADD1 53 signaling pathway,which led to restriction of PPRV replication in host cells.

Viral infection can induce endoplasmic reticulum stress(ERS)and unfolded protein reac-tion(UPR)in host cells.This study aims to further explore the effects of ERS induced by pest des petits ruminants virus(PPRV)infection on UPR signaling pathway,virus replication and apopto-sis of host cells.MTT assay,indirect immunofluorescence assay(IFA)and Western blot were used to observe the proliferation of PPRV in goat kidney cells(LDG-2).Western blot and real-time flu-orescence quantitative PCR(qRT-PCR)were used to observe the effects of PPRV infection on the expression levels of GRP78,PERK and its downstream signal molecules,apoptosis-related proteins Bcl-2 and Bax.The result indicated that the cell survival rate was significantly declined with evident cytopathic effect at 36 h post-infection,and the expression level of PPRV-N protein tended to be elevated,and was significantly higher than that of cell control at 30 h post-infection.Meanwhile,the expression levels of GRP78,p-eIF2α and GADD153,the ratio of p-PERK/PERK and p-eIF2α/eIF2α were significantly increased.Moreover,the expression levels of PPRV-N protein,GRP78,p-eIF2α and GADD1 53,the ratio of p-eIF2α/eIF2α and p-PERK/PERK were significantly decreased in PPRV-infected cells due to 4-PBA treatment.The expression level of apoptosis-related Bcl-2 was down-regulated,Bax was up-regulated,and the ratio of Bcl-2/Bax was significantly decreased.Therefore,the activation of PERK/eIF2α/GADD153 signaling pathway could be induced by PPRV infection resulting in alleviating of virus-induced ERS,which is beneficial to viral replication.Bloc-king PPRV-induced ERS could inhibit the activation of PERK signaling pathway and virus replica-tion.PPRV infection and prolonged ERS can induce apoptosis of LDG-2 cells.

MTT assay,indirect immunofluorescence assay(IFA)and real-time fluorescence quanti-tative PCR(qRT-PCR)were used to observe the proliferation of PPRV in goat kidney cells(LDG-2).Western blot and qRT-PCR were used to evaluate the effects of PPRV infection on the expres-sion levels of TLR2,MyD88,NF-κB signaling pathway-related factors and their downstream in-flammatory factors.The results indicated that the significantly decreased cell survival rate and ob-vious cytopathic effect were observed at 36 h post PPRV infection,and the mRNA expression level of PPRV-N gene was significantly up-regulated.At the same time,the expression levels of TLR2,MyD88,p-p65 and p-IκBα,the ratio of p-p65/p65 and p-IκBα/IκBα and the mRNA expression levels of downstream inflammatory factors TNFα,IL-1β,IL-4 and IL-10 were significantly increased.Mo-reover,the expression levels of PPRV-N mRNA,TLR2,MyD88,p-p65 and p-IκBα,the ratio of p-p65/p65 and p-IκBα/IκBα and the mRNA expression levels of downstream inflammatory factors IL-1β and IL-4 in PPRV-infected cells were significantly decreased in the presence of the inhibitor C29 of TLR2.These findings implied that the TLR2/MyD88/NF-κBα signaling pathway can be activated by PPRV infection,which is beneficial to the replication and spread of the virus.Blocking down the activation of TLR2 can inhibit MyD88/NF-κB signaling pathway and viral replication in PPRV-infected cells.

Purpose To investigate the pathological characteristics of loco-regional recurrent nasopharyngeal carcinoma ( rNPC ) . Methods Nasopharyngeal biopsy specimens of 46 rNPCs and 63 primary NPCs were collected. HE staining, immunohistochemistry and EBV small RNAs ( EBERs) in-situ hybridization were performed. Results The over-expression rates of both p63 and CK5/6 in rNPC were significantly higher than those of primary NPCs (P=0. 005, P=0. 026), while no statistical significance of Ki-67 over-ex-pression existed between the two groups ( P=0. 387 ) . More necrotic tissues, inflammatory exudates, giant bizarre carcinoma cells, desmoplastic stroma, giant bizarre tumor cells and higher degree of squamous differentiation were found in rNPCs. The carcinoma cells of 5 rNPCs were negative for both EBERs in-situ hybridization and LMP-1 immunohistochemical staining. Conclusion The loco-re-gional rNPC has two peaks of latency interval:2~5 and 9~11 years. The loco-regional rNPC cells have higher degree of squamous differentiation with higher expression of p63 and CK5/6, as well as more invasive ability. In addition, both EBERs in-situ hybridization and LMP-1 immunostaining are negative in 10. 87% (5/46) of loco-regional rNPC.