Molecular Mechanism Of PXN Involved In Anti-WSSV Immune Response In Procambarus Clarkii

Procambarus clarkii is one of the important aquaculture varieties in China.In recent years,crayfish aquaculture suffered from diseases.Various bacteria,fungi and virus infections caused a great loss to aquaculture industry.Among them,white spot syndrome virus(WSSV)infection caused particularly serious losses.Crayfish mainly relies on innate immunity to resist pathogen infection.The analysis of innate immunity mechanism can provide a theoretical reference for the prevention and treatment of WSSV.Peroxinectin(PXN),one kind of cell adhesion protein,is involved in immune response by participating in cell adhesion and signaling.PXN was first identified in invertebrates.PXN was reported to be involved in the removal of foreign bodies by hemocytes as an adhesion factor,and in the phagocytosis of bacteria by hemocytes as an opsonin.As well as binding bacterial components as recognition proteins and inhibiting bacterial infection by regulating the expression of antimicrobial peptides.The role of PXN in antiviral immunity remains to be revealed.In this study,crayfish was used as the research model to explore the molecular mechanism of PXN participating in anti-WSSV immunity.The WSSV replication experiment and the survival rate experiment of crayfish showed that PXN could inhibit the replication of WSSV.Further analysis showed that PXN could be secreted into the hemolymph after WSSV infection and recognize WSSV by binding with VP28,the main membrane protein of WSSV.Pull down and Co-IP experiments showed that PXN was bound to lipopolysaccharide and β-1,3-glucan-binding protein(LGBP)on cell membrane.After WSSV stimulation,LGBP responded to the WSSV stimulation,interfered in vivo or injected antibodies to block LGBP function.Analysis showed that the replication level of WSSV increased significantly,indicating that LGBP plays a role in crayfish’s resistance to WSSV infection.The interaction between PXN and LGBP is the key to the transmission of WSSV signals into cells.PXN collaborates with LGBP to promote the entry of Activator protein-1(AP-1)into the nucleus and initiate the transcription of the downstream effector molecule Crustin1(Cru1),thus participating in the anti-WSSV reaction.In summary,this study found that PXN recognizes WSSV by binding to VP28,and then activates the transcription factor AP-1 through interaction with LGBP,thus regulating the expression of Cru1 to resist WSSV infection.This study supplemented the knowledge system of antiviral immunity in innate immunity,which can provide certain theoretical reference for the prevention and control of WSSV.