Identification of cap-dependent endonuclease inhibitors with broad-spectrum activity against bunyaviruses

Shinsuke Toba, Akihiko Sato, Makoto Kawai, Yoshiyuki Taoda, Yuto Unoh, Shinji Kusakabe, Haruaki Nobori, Shota Uehara, Kentaro Uemura, Keiichi Taniguchi, Masanori Kobayashi, Takeshi Noshi, Ryu Yoshida, Akira Naito, Takao Shishido, Junki Maruyama, Slobodan Paessler, Michael J. Carr, William W. Hall, Kumiko YoshimatsuJiro Arikawa, Keita Matsuno, Yoshihiro Sakoda, Michihito Sasaki, Yasuko Orba, Hirofumi Sawa, Hiroshi Kida

Research output: Contribution to journalArticlepeer-review

Abstract

Viral hemorrhagic fevers caused by members of the order Bunyavirales comprise endemic and emerging human infections that are significant public health concerns. Despite the disease severity, there are few therapeutic options available, and therefore effective antiviral drugs are urgently needed to reduce disease burdens. Bunyaviruses, like influenza viruses (IFVs), possess a cap-dependent endonuclease (CEN) that mediates the critical cap-snatching step of viral RNA transcription. We screened compounds from our CEN inhibitor (CENi) library and identified specific structural compounds that are 100 to 1,000 times more active in vitro than ribavirin against bunyaviruses, including Lassa virus, lymphocytic choriomeningitis virus (LCMV), and Junin virus. To investigate their inhibitory mechanism of action, drug-resistant viruses were selected in culture. Whole-genome sequencing revealed that amino acid substitutions in the CEN region of drug-resistant viruses were located in similar positions as those of the CEN α3-helix loop of IFVs derived under drug selection. Thus, our studies suggest that CENi compounds inhibit both bunyavirus and IFV replication in a mechanistically similar manner. Structural analysis revealed that the side chain of the carboxyl group at the seventh position of the main structure of the compound was essential for the high antiviral activity against bunyaviruses. In LCMV-infected mice, the compounds significantly decreased blood viral load, suppressed symptoms such as thrombocytopenia and hepatic dysfunction, and improved survival rates. These data suggest a potential broad-spectrum clinical utility of CENis for the treatment of both severe influenza and hemorrhagic diseases caused by bunyaviruses.

Original languageEnglish (US)
Article numbere2206104119
JournalProceedings of the National Academy of Sciences of the United States of America
Volume119
Issue number36
DOIs
StatePublished - Sep 6 2022

Keywords

  • antiviral compounds
  • bunyavirus
  • cap-dependent endonuclease

ASJC Scopus subject areas

  • General

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