AMP-activated kinase (AMPK) promotes innate immunity and antiviral defense against Zika virus induced ocular infection

Abstract

Abstract Purpose We recently reported that Zika Virus infected multiple retinal cell types and caused chorioretinal atrophy in mouse eyes. In this study, we investigated the potential role of AMPK, a master regulator of cellular metabolism, in pathogenesis of ocular ZIKV infection. Methods Primary human RPE cells were infected with ZIKV for various time points and AMPK phosphorylation was detected Western blotting (WB). AMPK activity was modulated by pharmacological activators (AICAR and Metformin) and inhibitors (Compound C) of AMPK. ZIKV replication was assessed by immunofluorscence staining for 4G2 and western blot detection of NS3 proteins. For in vivo studies B6 mice eye were challenged with ZIKV with or without AICAR treatment and disease progression were measured by fundus imaging. Activation of innate immune and antiviral response genes was assessed by qPCR. Results ZIKV challenge upregulated the AMPK phosphorylation in Pr. RPE cells in a time-dependent fashion. Our results indicate that AMPK deficient mouse embryonic fibroblast (MEF) cells were more permissive to ZIKV replication as compared to WT MEFs. AMPK activation using AICAR and Metformin restricted ZIKV replication in Pr. RPE cells and presence of Compound C reversed the effect of AICAR/Metformin. In vivo AICAR treatment ameliorated ZIKV-induced chorioretinal atrophy in mice with increased antiviral responses. ZIKV infection leads to activation of MEK pathways and an MEK pathways inhibitor, U0126, attenuated ZIKV replication. Conclusion Collectively, these findings indicate the AMPK activation evokes antiviral innate responses and restricts ZIKV replication. Hence, targeting AMPK signaling can be explored to develop anti-viral therapy against ZIKV infection.