The Antiviral Effect of Viperin for Type IV Dengue Virus Through the End of the C-Terminal

Dengue fever (DF) is caused by the highly contagious dengue virus (DENV), which is harmful to the human body. Viperin is an antiviral protein that is highly expressed in cells infected with DENV. We detected expression of viperin in human umbilical vein endothelial cells (HUVECs) infected with the dengue type 4 virus (DENV-IV) by reverse transcription-fluorescence quantitative PCR (RT-QPCR) and western blot, virus titration technique after construction of lentivirus vectors with viprin overexpression (ovR-viperin), viperin silent expression (siR-viperin), S-adenosylmethioninase mutation in the α-helix region of amphiphilic at the N-terminal of viperin (N-SAM mutation) and C-terminal mutation (C-ter mutation). The purpose of this study was to investigate the mechanism of viperin against DENV-IV. The results showed that expression of viperin protein and mRNA increased significantly after DENV-IV infection of HUVECs. The virulence of DENV-IV in infected HUVECs was decreased significantly after overexpression of the viperin gene, while virulence increased after viperin gene expression silencing. DENV-IV virulence in HUVECs remained inhibited after N-SAM mutation. The virulence of DENV-IV in HUVECs after C-terminal mutation of viperin was significantly lower than in HUVECs transfected with viperin overexpression plasmids. We concluded that DENV-IV can induce expression of the antiviral protein viperin, and the effect of viperin on DENV-IV may be related to the C-terminal.