In Vitro Antiviral Activity And Underlying Molecular Mechanisms Of Dipotassium Glycrrhetate Against Porcine Reproductive And Respiratory Syndrome Virus

Objectives:In this study, we investigated the inhibitory effect of Dipotassium glycyrrhetate (DG), a derivative of glycyrrhetinic acid, on PRRSV infection ability, and underlyed molecular mechanisms of DG against PRRSVMethods:The effects of DG on PRRSV N gene/protein were investigated using real-time PCR, Western blot and immunofluorescence assay. In addition, the mRNA expressions of the DG on PABP, PCBP1and PCBP2were analyzed by real-time PCR.Results:1. Real-time PCR was used to quantify PRRSV copy-number based on the N gene. DG addition could strongly inhibit the N gene expression in a dose-dependent manner, and the DG possessed a higher inhibitory ability than ribavirin. Cells were treated with DG and sampled at4,14,20,36and52hpi. DG and ribavirin could reduce N gene copies, the antiviral effect of ribavirin was in decline from4h to52h, but DG at4mg/ml could maintain the antiviral effect for an extended period of time from14h to52h.2. Expression of viral N protein in DG treated cells was detected by Western blot and IFA. The inhibitory effect of DG on PRRSV N protein expression showed a dose-dependently manner; in the concentration of4mg/ml,2mg/ml and1mg/ml, DG showed better inhibitory effects than ribavirin.3. When the infected cells received DG, the mRNA levels of PABP, PCBP1were decreased, the mRNA levels of PCBP2were increased, compared with cell control; the mRNA levels of PCBP1were decreased, the mRNA levels of PCBP2were increased, compared with PRRSV control; addition of ribavilin resulted in the expression of PABP, PCBP1and PCBP2was increased, compared with other groups.Conclusion:Our study demonstrates that DG could effectively inhibit the PRRS virus via multiple pathways including inhibition of virus replication and N gene expression and the mRNA levels of PCBP1were decreased. DG can serve as a potential chemical for PRRSV prevention and control.