ISG15 facilitates cellular antiviral response to dengue and west nile virus infection in vitro

Abstract

BackgroundDengue virus (DENV) and West Nile virus (WNV), close siblings of the Flaviviridae family, are the causative agents of Dengue hemorraghic shock or West Nile meningoencephalitis respectively. Vaccines against these two flaviviruses are currently unavailable. Interferon- Stimulated Gene 15 (ISG15), encoding an ubiquitin-like protein, is significantly induced by type I interferons or viral infections. Its roles in viral infections, however, vary with viruses, being either anti- or pro-viral. The exact roles of ISG15 in DENV and WNV infections remain unknown. In the current study, we evaluated the relevancies of ISG15 to DENV and WNV infection of a mouse macrophage cell line RAW264.7.FindingsQuantitative PCR showed that mouse Isg15 was dramatically induced in DENV or WNV- infected RAW264.7 cells compared with non-infected cells. Isg15 and two other Jak-Stat related genes, Socs1 and Socs3, were silenced using siRNA mediated RNA interference. The intracellular DENV and WNV loads, as determined by quantitative PCR, were significantly higher in Isg15 silenced cells than control cells. The expression levels of interferon beta 1 (Ifnb1) were increased significantly in Isg15, Socs1 or Socs3 siRNA treated cells. Further investigation indicated that protein modification by ISG15, so called ISGylation, was significantly enhanced in DENV-infected cells compared to that in non-infected cells.ConclusionsThese findings suggest that ISG15 plays an anti-DENV/WNV function via protein ISGylation.

Guanylate-binding protein 1 participates in cellular antiviral response to dengue virus

“…A number of genes were found up- or down-regulated upon DENV infection, as reported in our previous work (Additional file 1of Ref. [22]). Among them, Gbp1 was upregulated 3.97-fold in DENV infected cells in comparison to uninfected controls.…”

Zika virus infects cells lining the blood-retinal barrier and causes chorioretinal atrophy in mouse eyes

“…Moreover, ZIKV infection induced the expression of several IFN-induced antiviral genes, including ISG15, OAS2, and MX1. These IFN-stimulated genes (ISGs) have been shown to exert strong antiviral effects and restrict the viral replication of flaviviruses like DENV and WNV (58,59). Marked upregulation of these ISGs suggests a role for type I IFNs in controlling ZIKV infection and replication in vivo.…”

Influence of genome-scale RNA structure disruption on the replication of murine norovirus—similar replication kinetics in cell culture but attenuation of viral fitness in vivo

“…At specified time points post-infection (8 or 24 h post-infection), total RNA was extracted from uninfected or infected RAWs using an RNeasy kit (Qiagen) and was subjected to DNAse 1 (Promega) treatment before being reverse transcribed using M-MLV reverse transcriptase and random hexamer primers (Promega). Semi-quantitative PCR was performed using a Rotorgene Q cycler (Qiagen) using SensiFAST™ SYBR Hi-ROX One-Step master mix (Bioline) and primers (0.8 Μm) specific to TNF, ISG15 (35), ISG54 and ISG56 (36). Each gene was normalized to HPRT1 (37) or 18 s rRNA (primer details in Supplementary Table S1), and the relative expression was calculated using 2 − ΔΔCt (38).…”