OBJECTIVE To investigate the inhibitory effect of human β defensin-3(HBD3)on the replication of in-fluenza A virus(IAV)[A/PR/8/34(H1N1)virus strain]in human bronchial epithelial cells(BEAS-2B)via the mitochondrial autophagy pathway.METHODS BAS-2B cells were infected with IAV,and cell condition observa-tion:plaque assay and light microscopy.Drug treatment:HBD3,autophagy agonist rapamycin(Rapa),autoph-agy inhibitor LY294002;The expression levels of TUFM、MAVS、NP、M2 and PB1-F2 genes were detected by real-time fluorescence quantitative polymerase chain reaction(qPCR).Western blot was used to detect the protein expression levels of P62、LC3Ⅱ and LC3Ⅰ.RESULTS Plaque formation experiments showed that the number of plaques increased with the increase of viral titer.With the increase of viral titer or the prolongation of infection time,the expres-sion levels of TUFM,MAVS,NP,M2 and PB1-F2 genes in BEAS-2 B cells gradually increased,the expression levels of P62 protein decreased,and the protein expression levels of LC3Ⅱ/LC3Ⅰ increased(P＜0.05).Forty-eight hpi of BE-AS-2B cells with IAV,the number of cells in the IAV group was significantly lower than that in the IAV+HBD3 group,the intercellular space was enlarged,and the cells shrunk significantly.Compared with the IAV group,the expression lev-els of TUFM,MAVS,NP,M2 and PB1-F2 genes in BEAS-2B cells in the IAV+HBD3 group decreased,the expres-sion levels of P62 protein increased,and the protein levels of LC3Ⅱ/LC3Ⅰ decreased(P＜0.05).Gene expression levels of TUFM,MAVS,NP,M2 and PB1-F2 were in the IAV+Rapa+HBD3 group were lower than those in the IAV+Ra-pa group(P＜0.05).The protein expression level of P62 in the IAV+Rapa+HBD3 group was higher than that in the IAV+Rapa group(P＜0.05).The protein expression levels of LC3Ⅱ/LC3Ⅰ were lower in the IAV+Rapa+HBD3 group than in the IAV+Rapa group(P＜0.05).CONCLUSION With the increase of viral titer or the prolongation of in-fection time,the proliferation of IAV in BEAS-2B cells increases,and the cell damage exacerbates.HBD3 can inhibit the replication of IAV after its entry into the cells;HBD3 can protect host cells and inhibit IAV replication by inhibiting MA-VS,TUFM-mediated mitophagy pathways.

OBJECTIVE To investigate the inhibitory effect of human β defensin-3(HBD3)on the replication of in-fluenza A virus(IAV)[A/PR/8/34(H1N1)virus strain]in human bronchial epithelial cells(BEAS-2B)via the mitochondrial autophagy pathway.METHODS BAS-2B cells were infected with IAV,and cell condition observa-tion:plaque assay and light microscopy.Drug treatment:HBD3,autophagy agonist rapamycin(Rapa),autoph-agy inhibitor LY294002;The expression levels of TUFM、MAVS、NP、M2 and PB1-F2 genes were detected by real-time fluorescence quantitative polymerase chain reaction(qPCR).Western blot was used to detect the protein expression levels of P62、LC3Ⅱ and LC3Ⅰ.RESULTS Plaque formation experiments showed that the number of plaques increased with the increase of viral titer.With the increase of viral titer or the prolongation of infection time,the expres-sion levels of TUFM,MAVS,NP,M2 and PB1-F2 genes in BEAS-2 B cells gradually increased,the expression levels of P62 protein decreased,and the protein expression levels of LC3Ⅱ/LC3Ⅰ increased(P＜0.05).Forty-eight hpi of BE-AS-2B cells with IAV,the number of cells in the IAV group was significantly lower than that in the IAV+HBD3 group,the intercellular space was enlarged,and the cells shrunk significantly.Compared with the IAV group,the expression lev-els of TUFM,MAVS,NP,M2 and PB1-F2 genes in BEAS-2B cells in the IAV+HBD3 group decreased,the expres-sion levels of P62 protein increased,and the protein levels of LC3Ⅱ/LC3Ⅰ decreased(P＜0.05).Gene expression levels of TUFM,MAVS,NP,M2 and PB1-F2 were in the IAV+Rapa+HBD3 group were lower than those in the IAV+Ra-pa group(P＜0.05).The protein expression level of P62 in the IAV+Rapa+HBD3 group was higher than that in the IAV+Rapa group(P＜0.05).The protein expression levels of LC3Ⅱ/LC3Ⅰ were lower in the IAV+Rapa+HBD3 group than in the IAV+Rapa group(P＜0.05).CONCLUSION With the increase of viral titer or the prolongation of in-fection time,the proliferation of IAV in BEAS-2B cells increases,and the cell damage exacerbates.HBD3 can inhibit the replication of IAV after its entry into the cells;HBD3 can protect host cells and inhibit IAV replication by inhibiting MA-VS,TUFM-mediated mitophagy pathways.