Functional And Mechanistic Studies Of Pvf/Pvr Signaling In Host-Virus Interactions In Marsupenaeus Japonicus

Shrimp aquaculture is an important economic industry in China,but has long been threatened by disease.White spot syndrome virus(WSSV)is a major viral pathogen in shrimp aquaculture and is a huge hazard to shrimp aquaculture.Therefore,discovering important factors in disease immunity and uncovering their mechanisms can contribute to disease control and sustainable development of shrimp aquaculture.The platelet derived growth factor family is a highly conserved and widespread group of growth factors in organisms.Platelet derived growth factor(PDGF)and vascular endothelial growth factor(VEGF)are the main members of this family.This family is functionally diverse and has been reported to be involved in the regulation of development,immunity and metabolism of the organism,and can be a key therapeutic target for a variety of clinical diseases.However,the functions and mechanisms of this family in shrimp-WSSV interactions are unknown.We found that MjPvf2(PDGF/VEGF related factor 2)in the Pvf family could significantly respond to WSSV stimulation by Stat signaling and exert an inhibitory effect on viral infection in Marsupenaeus japonicus.Inhibition of MjPvf2 expression by RNAi technology leads to a significant increase in the level of viral infection in shrimp.MjPvr3(PDGF/VEGF related receptor 3)functions as a downstream receptor of MjPvf2.Virus infection is closely related to host lipid metabolism.We found that WSSV infection leads to a significant decrease in triglyceride content in the hepatopancreas of shrimp,and MjPvf2/MjPvr3 could relieve the lipid consumption caused by WSSV infection by increasing the triglyceride content in the hepatopancreas of shrimp.Blocking lipid synthesis could promote WSSV infection.We further found that MjPvf2/MjPvr3 signaling induces hydroxysteroid dehydrogenase(HSD)expression through activation of the downstream ERK/SREBP pathway to promote lipid synthesis and exert antiviral functions.In conclusion,this study reveals the important functions and mechanisms of MjPvf2/MjPvr3 signaling in the antiviral immunity of shrimp,which provides new ideas for disease control in shrimp culture.