Matrine inhibits replication of Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) by influencing the activation of Nsp9

Abstract

Matrine is the major active compound found in the root of Chinese herbal medicine Sophora flavescens and has a wide range of pharmacological efficacies. Our previous studies showed that Matrine could inhibit the replication of porcine reproductive and respiratory syndrome virus (PRRSV) directly. However, the underlying inhibition mechanism remains unknown. The main aim of this study was to explore the inhibitory mechanism of Matrine in PRRSV replication in vitro. The mRNA expression of PRRSV N gene was determined using RT-qPCR. The expression of pERK1/2 protein was evaluated using Western blot and the effect of Matrine on PRRSV Nsp9 activity was studied using dual luciferase reporter gene assay. The results showed that Matrine suppress the mRNA transcription of PRRSV N gene in Marc-145 cells at 3 h and 24 h post PRRSV infection and had no inhibitory effect on the ERK1/2 signal pathway activated by PRRSV. The results of dual luciferase reporter gene assay showed that Matrine suppressed the interaction of Nsp9 with promoter p107. Taken into account the results above, our study demonstrated that Matrine inhibit the activity of Nsp9 to suppress the virus replication.