Description
Identification of chemical compounds inhibiting Ebola Virus replication
Riva Laura1, Langer Simon1, Edwards Megan2, Martin-Sancho Laura1, De Jesus Paul D.1, Davey Robert3, Shaw Megan4, Basler Christopher2, Chanda Sumit K.1
1Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA; 2Center of Microbial Pathogenesis, Institute of Biomedical Sciences, Georgia State University, Atlanta, GA, USA; 3Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, TX, USA; 4Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
Zaire Ebolavirus (EBOV) and Marburgvirus represent emerging, non-segmented, negative-sense RNA viruses, belonging to the family of Filoviridae. Infection can cause severe hemorrhagic fever and frequently leads to fatal outcomes in humans. The 2014-2016 West Africa epidemics caused more than 28,000 reported cases and approximately 11,000 deaths. The lack of specific antivirals to treat these infections strongly impedes the ability to efficiently contain their spread. The strict biosafety precautions to work with Filoviruses, however, make it challenging to perform large-scale drug discovery screens. The recent development of an efficient in vitro EBOV minigenome replication system allows monitoring viral replication in a BSL-1 environment. EBOV RNA-dependent RNA polymerase (RDRP) complex can be reconstituted in HEK-293T cells through the expression of EBOV NP, VP35, VP30 and L. RDRP activity is measured through the co-expression of a model viral RNA encoding a Luciferase reporter gene flanked by virus-derived cis-acting regulatory sequences. Leveraging this system we performed a screen of 12,480 small chemical compounds to identify potential antiviral drugs. 169 compounds showed more than 70% inhibition of EBOV replication and were selected for further validation. Among these candidates, close to 80% could be confirmed. Subsequently, dose-response studies were performed and the effects of each compound on both replication and cytotoxicity were evaluated. Compounds showing a strong dose-response inhibitory effect on replication with weak cell toxicity were then selected for future follow-up studies, to determine their antiviral potency towards wild type EBOV and evaluate potential activity against other Filoviruses. In summary, we took advantage of an EBOV minigenome replication system to screen chemical compounds, aiming to identify effective antivirals against Filoviruses.