Identification of entry inhibitors with 4-aminopiperidine scaffold targeting group 1 influenza A virus

Antiviral Res. 2020 May;177:104782. doi: 10.1016/j.antiviral.2020.104782. Epub 2020 Mar 25.


Influenza A viruses (IAVs) cause seasonal flu and occasionally pandemics. The current therapeutics against IAVs target two viral proteins - neuraminidase (NA) and M2 ion-channel protein. However, M2 ion channel inhibitors (amantadine and rimantadine) are no longer recommended by CDC for use due to the emergence of high level of antiviral resistance among the circulating influenza viruses, and resistant strains to NA inhibitors (oseltamivir and zanamivir) have also been reported. Therefore, development of novel anti-influenza therapies is urgently needed. As one of the viral surface glycoproteins, hemagglutinin (HA) mediates critical virus entry steps including virus binding to host cells and virus-host membrane fusion, which makes it a potential target for anti-influenza drug development. In this study, we report the identification of compound CBS1116 with a 4-aminopiperidine scaffold from a chemical library screen as an entry inhibitor specifically targeting two group 1 influenza A viruses, A/Puerto Rico/8/34 (H1N1) and recombinant low pathogenic avian H5N1 virus (A/Vietnam/1203/04, VN04Low). Mechanism of action studies show that CBS1116 interferes with the HA-mediated fusion process. Further structure activity relationship study generated a more potent compound CBS1117 which has a 50% inhibitory concentration of 70 nM and a selectivity index of ~4000 against A/Puerto Rico/8/34 (H1N1) infection in human lung epithelial cell line (A549).

Keywords: Fusion inhibitor; Hemagglutinin; Influenza a viruses; Structure activity relationship; Virus entry.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • A549 Cells
  • Antiviral Agents / pharmacology*
  • Humans
  • Influenza A Virus, H1N1 Subtype / drug effects
  • Influenza A Virus, H1N1 Subtype / physiology
  • Influenza A Virus, H5N1 Subtype / drug effects
  • Influenza A Virus, H5N1 Subtype / physiology
  • Influenza A virus / drug effects*
  • Influenza A virus / physiology
  • Piperidines / pharmacology*
  • Small Molecule Libraries / pharmacology
  • Structure-Activity Relationship
  • Virus Internalization / drug effects*
  • Virus Replication / drug effects


  • 4-aminopiperidine
  • Antiviral Agents
  • Piperidines
  • Small Molecule Libraries