The Antimalarial Compound Atovaquone Inhibits Zika and Dengue Virus Infection by Blocking E Protein-Mediated Membrane Fusion
Mizuki Yamamoto,
Takeshi Ichinohe,
Aya Watanabe,
Ayako Kobayashi,
Rui Zhang,
Jiping Song,
Yasushi Kawaguchi,
Zene Matsuda,
Jun-ichiro Inoue
Affiliations
Mizuki Yamamoto
Research Center for Asian Infectious Diseases, The Institute of Medical Science, The University of Tokyo, Tokyo 113-0033, Japan
Takeshi Ichinohe
Division of Viral Infection, Department of Infectious Disease Control, International Research Center for Infectious Diseases, The Institute of Medical Science, The University of Tokyo, Tokyo 113-0033, Japan
Aya Watanabe
Research Center for Asian Infectious Diseases, The Institute of Medical Science, The University of Tokyo, Tokyo 113-0033, Japan
Ayako Kobayashi
Research Center for Asian Infectious Diseases, The Institute of Medical Science, The University of Tokyo, Tokyo 113-0033, Japan
Rui Zhang
Laboratory of Structural Virology and Immunology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100864, China
Jiping Song
China-Japan Joint Laboratory of Molecular Immunology & Microbiology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100864, China
Yasushi Kawaguchi
Research Center for Asian Infectious Diseases, The Institute of Medical Science, The University of Tokyo, Tokyo 113-0033, Japan
Zene Matsuda
Research Center for Asian Infectious Diseases, The Institute of Medical Science, The University of Tokyo, Tokyo 113-0033, Japan
Jun-ichiro Inoue
Research Center for Asian Infectious Diseases, The Institute of Medical Science, The University of Tokyo, Tokyo 113-0033, Japan
Flaviviruses bear class II fusion proteins as their envelope (E) proteins. Here, we describe the development of an in vitro quantitative mosquito-cell-based membrane-fusion assay for the E protein using dual split proteins (DSPs). The assay does not involve the use of live viruses and allows the analysis of a membrane-fusion step independent of other events in the viral lifecycle, such as endocytosis. The progress of membrane fusion can be monitored continuously by measuring the activities of Renilla luciferase derived from the reassociation of DSPs during cell fusion. We optimized the assay to screen an FDA-approved drug library for a potential membrane fusion inhibitor using the E protein of Zika virus. Screening results identified atovaquone, which was previously described as an antimalarial agent. Atovaquone potently blocked the in vitro Zika virus infection of mammalian cells with an IC90 of 2.1 µM. Furthermore, four distinct serotypes of dengue virus were also inhibited by atovaquone with IC90 values of 1.6–2.5 µM, which is a range below the average blood concentration of atovaquone after its oral administration in humans. These findings make atovaquone a likely candidate drug to treat illnesses caused by Zika as well as dengue viruses. Additionally, the DSP assay is useful to study the mechanism of membrane fusion in Flaviviruses.
