In Vitro Antiviral Activity And Underlying Molecular Mechanisms Of Sodium Tanshinone ⅡA Sulfonate Against Porcine Reproductive And Respiratory Syndrome Virus

Objectives:This study aimed to investigate the effect of Sodium tanshinone IIA sulfonate (STS)on the expression of gene Beclinl1、ATG5、ATG7 involved in cell autophagy,together with the ability of STS on inhibiting PRRSV infection to elucidate the molecular mechanisms for STS anti-PRRSV. Methods:Real-time PCR, Western blot and immunofluorescence assay were used to invesstigate the effect of STS on PRRSV N gene/protein biosynthesis. In addition, the mRNA expressions of ATG5, ATG7 and Beclin1 were analyzed by real-time PCR and Western blot.Results:1. When the infected cells received STS, the mRNA and protein levels of ATG5, ATG7 and Beclin 1 were decreased at 12,24 and 36hpi,0.0625mg/ml、0.03125mg/ml inhibit theATG5gene expression at 12,24hpi possessed a higher inhibitory ability than ribavirin.;and,0.0625mg/ml inhibit the Beclinl gene expression at 36hpi showed better inhibitory effects than ribavirin.2. Real-time PCR was used to quantify PRRSV copy-number based on the N gene. Cells were treated with STS and ribavirin could inhibit the N gene expression at 12,24hpi. And at 36hpi, the0.0625mg/ml possessed a higher inhibitory ability than ribavirin.3. Expression of viral N protein in STS treated cells was detected by Western blot and IFA. The inhibitory effect of STS on PRRSV N protein expression showed a dose-dependently manner; in the concentration of 0.0625mg/ml,0.03125mg/ml; STS showed better inhibitory effects than ribavirin at 36hpi.Conclusion:Our study suggests that STS could effectively inhibit the PRRS virus infection via multiple pathways including inhibition of virus replication and down-regulation N gene expression and the mRNA levels of ATG5. ATG7and Beclinl were decreased. STS can serve as a potential chemical for PRRSV prevention and control.