Roles Of Bmo-miR-3378 In Defense Of Bombyx Mori Cells Against BmNPV Infection

To explore the function of bmo-mi R-3378 on the interaction between the silkworm,Bombyx mori L.and the baculovirus,B.mori nucleopolyhedrovirus(BmNPV),cellular biological effects,viral pathological effects,and cellular proteomic effects of bmo-miR-3378 expression changes in BmN cells were analyzed by using real-time quantitative PCR,biochemical analysis and protein sequencing technology,after bmo-miR-3378 expression system was constructed.1.Transfection and expression of bmo-miR-3378 in BmN cellsThe expression of bmo-mi R-3378 was significantly decreased in BmN cells after infected by BmNPV.Transfection of bmo-miR-3378 mimic or inhibitor could increase or decrease significantly the amount of bmo-miR-3378 in BmN cells.2.Cellular biological effects of bmo-miR-3378Over-expression of bmo-miR-3378 in BmN cells caused significantly higher cellular mortality,lower cellular viability and spreading,and increased apoptosis.However,inhibited expression of bmo-miR-3378 reversed these effects.3.Viral pathological effects of bmo-miR-3378Over-expression of bmo-miR-3378 in BmN cells inhibited BmNPV DNA replication and virulence.However,inhibited expression of bmo-miR-3378 reversed these effects.4.Cellular proteomic effects of bmo-miR-3378There were 211 proteins significantly differently expressed in BmN cells after transfected with bmo-miR-3378 mimic,as 160 of proteins in the cells transfected with bmo-miR-3378 inhibitor.49 of target genes and their regulation pathway were found by comparison of predicted target genes of bmo-miR-3378 with differently expressed proteins.According to the above results,it suggested that BmNPV might preclude the induced apoptosis of BmN cells indirectly by inhibition of bmo-miR-3378 expression to maintain viral replication and proliferation during the early stage of infection.This mechanism of baculovirus against host anti-virus defense was found for the first time,as an alternative of baculovirus directly regulating host apoptosis using viral IAPs.These results will contribute to further understanding the regulation mechanisms of miRNAs on insect immune,and providing new technical ideas and platform for systematic analysis of biological functions of miRNAs and their target genes,which may be used for the future application in early diagnosis to viral diseases,silkworm disease controlling and disease-resistant breeding,and sustainable industrial development of silkworm Bio-reactor.