Amiodarone inhibits Ebola virus infection by Blocking Viral Entry Into Target Cells Through Late Endosomes

Objectives: Ebola Virus Disease is one of the most lethal transmissible infections characterized by a high fatality rate. Recently, we demonstrated that the antiarrhythmic drug amiodarone inhibits Ebola virus infection interfering with the fusion of the viral envelope with the endosomal membrane. In the present work we further investigated the antiviral activity of amiodarone on Ebola virus infection. Methods: In addition to the wild type Sudan ebolavirus (SUDV), two recombinant systems were used, the Vesicular Stomatitis virus (VSV) and Ebola virus-like particles (EBOVLPs), to clarify the effect of amiodarone on Ebola virus infection. Both recombinant VSV and EBOVLPs were pseudotyped with the Zaire ebolavirus glycoprotein (GP). Results: Amiodarone time addition experiments on Vero cells infected with the SUDV show that amiodarone strongly inhibits Ebola virus infection if the drug is present during the adhesion and/or post-adhesion times. The inhibition of SUDV infection decreases if the drug is added at later time points after viral infection. To better characterize the fate of viral particles during the entry step, we optimized a protocol for the production and purification of fluorescent EBOVLPs. Preliminary experiments with EBOVLPs confirmed our previous results supporting a block of the viral particles inside the endosomes with a GP-mediated mechanism. In addition, results with the VSV-GP suggest that amiodarone decreases the ability of SUDV to bind to target cells after drug pre-treatment. Conclusions: These findings suggest that amiodarone is able to inhibit Ebola virus infection targeting several steps of viral entry phase providing further insights on the ability of amiodarone of inhibiting Ebola virus infection in vitro.