Emetine inhibits Zika and Ebola virus infections through two molecular mechanisms: inhibiting viral replication and decreasing viral entry

a Chemical structures of emetine and cephaeline. b Dose-response curve showing the effect of emetine treatment on ZIKV NS1 protein expression (red) and cell viability (black) in HEK293 cells exposed to ZIKV MR766 strain. c Western blot of ZIKV NS1 protein after treatment of SNB-19 cells with varying concentrations of Emetine. SNB-19 cells were treated with emetine for 1？h before inoculation with ZIKV strains PRVABC59, FSS13025, or MR766 (MOI？=？1), and cells were harvested 24？h after infection for Western Blot analysis. d Immunofluorescent images of astrocytoma cells stained for ZIKV PRVABC59 envelope (ENV) protein (green), nuclei (blue) and treated with emetine. Scale bar=100？μm. e Dose–response curves from cells in (d) showing the inhibition effect of emetine on ZIKV PRVABC59 infection measured by ENV+？SNB-19 cells (green), and cell number by nuclear counting (blue). f SNB-19 cells were treated with emetine at increasing concentrations for 1？h before infection with PRVABC59 at a MOI？=？1 (n？=？3 cultures). Cell culture supernatant was collected 24？h after infection, and infectious virions were quantified for focus-forming units (FFU) using Vero cells. All curves represent best fits for calculating the IC50 values (graph inset). All values represent mean？±？SD (N？=？3 replicates