The Anticoagulant Nafamostat Potently Inhibits SARS-CoV-2 S Protein-Mediated Fusion in a Cell Fusion Assay System and Viral Infection In Vitro in a Cell-Type-Dependent Manner
Mizuki Yamamoto,
Maki Kiso,
Yuko Sakai-Tagawa,
Kiyoko Iwatsuki-Horimoto,
Masaki Imai,
Makoto Takeda,
Noriko Kinoshita,
Norio Ohmagari,
Jin Gohda,
Kentaro Semba,
Zene Matsuda,
Yasushi Kawaguchi,
Yoshihiro Kawaoka,
Jun-ichiro Inoue
Affiliations
Mizuki Yamamoto
Research Center for Asian Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan
Maki Kiso
Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan
Yuko Sakai-Tagawa
Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan
Kiyoko Iwatsuki-Horimoto
Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan
Masaki Imai
Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan
Makoto Takeda
Department of Virology 3, National Institute of Infectious Diseases, Musashimurayama, Tokyo 208-0011, Japan
Noriko Kinoshita
Disease Control and Prevention Center, National Center for Global Health and Medicine, Tokyo 162-8655, Japan
Norio Ohmagari
Disease Control and Prevention Center, National Center for Global Health and Medicine, Tokyo 162-8655, Japan
Jin Gohda
Research Center for Asian Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan
Kentaro Semba
Department of Life Science and Medical Bio-Science, Waseda University, Shinjuku-ku, Tokyo 162-8480, Japan
Zene Matsuda
Research Center for Asian Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan
Yasushi Kawaguchi
Research Center for Asian Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan
Yoshihiro Kawaoka
Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan
Jun-ichiro Inoue
Research Center for Asian Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan
Although infection by SARS-CoV-2, the causative agent of coronavirus pneumonia disease (COVID-19), is spreading rapidly worldwide, no drug has been shown to be sufficiently effective for treating COVID-19. We previously found that nafamostat mesylate, an existing drug used for disseminated intravascular coagulation (DIC), effectively blocked Middle East respiratory syndrome coronavirus (MERS-CoV) S protein-mediated cell fusion by targeting transmembrane serine protease 2 (TMPRSS2), and inhibited MERS-CoV infection of human lung epithelium-derived Calu-3 cells. Here we established a quantitative fusion assay dependent on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) S protein, angiotensin I converting enzyme 2 (ACE2) and TMPRSS2, and found that nafamostat mesylate potently inhibited the fusion while camostat mesylate was about 10-fold less active. Furthermore, nafamostat mesylate blocked SARS-CoV-2 infection of Calu-3 cells with an effective concentration (EC)50 around 10 nM, which is below its average blood concentration after intravenous administration through continuous infusion. On the other hand, a significantly higher dose (EC50 around 30 μM) was required for VeroE6/TMPRSS2 cells, where the TMPRSS2-independent but cathepsin-dependent endosomal infection pathway likely predominates. Together, our study shows that nafamostat mesylate potently inhibits SARS-CoV-2 S protein-mediated fusion in a cell fusion assay system and also inhibits SARS-CoV-2 infection in vitro in a cell-type-dependent manner. These findings, together with accumulated clinical data regarding nafamostat’s safety, make it a likely candidate drug to treat COVID-19.
