Study On The Mechanism Of Vimentin In Porcine Reproductive And Respiratory Syndrome Virus During Replication

Porcine reproductive and respiratory syndrome(PRRS)is an infectious disease caused by PRRS virus(PRRSV)and results in huge economic losses to the global pig industry.Vimentin,as one of host cell proteins,is involved in PRRSV invasion during viral infection.Recent studies have shown that vimentin plays a significant role in viral replication.However,the detailed mechanisms of vimentin involved in PRRSV replication remain to be elucidated.Therefore,a series of experiments were carried out to explore how vimentin took effect on PRRSV replication in the current study:(1)After PRRSV infection of MARC-145 cells and PAM cell line CRL-2843-CD163,confocal microscopy was utilized to observe that vimentin fibers reorganized and condensed into “cage-like” structures,which enwrapped PRRSV replication complex(RC)marked by viral double-stranded RNAs(ds RNAs)and non-structural protein 9(nsp9)at 9 h post infection.(2)After destroying the vimentin “cage-like” structures with 3,3'-iminodipropionitrile(IDPN)and acrylamide,the dense ds RNAs were dispersed in the cytoplasm.Furthermore,the results of quantitative real-time PCR(RT-q PCR)and virus titer test revealed that vimentin rearrangement was important for viral replication and infection.(3)Immunoblotting(IB)detected an increase in the phosphorylation level of vimentin during PRRSV infection.Vimentin was shown to be phosphorylated at the serine residue of position 38(Ser38)by calmodulin-dependent protein kinase II(Ca MKII)with a specific inhibitor KN-93,responsible for vimentin reorganization and PRRSV replication.This study determines vimentin reorganization during PRRSV infection,demonstrates that vimentin reorganization is important for viral replication,and explores the detailed mechanisms involved in this process.These results expand the knowledge of PRRSV replication,and provide novel targets for prevention and control of PRRSV.