title: A novel small-molecule inhibitor of influenza A virus acts by suppressing PA endonuclease activity of the viral polymerase.
abstract: The RNA-dependent RNA polymerase of influenza A virus comprises conserved and independently-folded subdomains with defined functionalities. The N-terminal domain of the PA subunit (PA(N)) harbors the endonuclease function so that it can serve as a desired target for drug discovery. To identify a class of anti-influenza inhibitors that impedes PA(N) endonuclease activity, a screening approach that integrated the fluorescence resonance energy transfer based endonuclease inhibitory assay with the DNA gel-based endonuclease inhibitory assay was conducted, followed by the evaluation of antiviral efficacies and potential cytotoxicity of the primary hits in vitro and in vivo. A small-molecule compound ANA-0 was identified as a potent inhibitor against the replication of multiple subtypes of influenza A virus, including H1N1, H3N2, H5N1, H7N7, H7N9 and H9N2, in cell cultures. Combinational treatment of zanamivir and ANA-0 exerted synergistic anti-influenza effect in vitro. Intranasal administration of ANA-0 protected mice from lethal challenge and reduced lung viral loads in H1N1 virus infected BALB/c mice. In summary, ANA-0 shows potential to be developed to novel anti-influenza agents.
authors.affiliation: Department of Microbiology, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Shuofeng
authors.initials: S
authors.lastname: Yuan
authors.affiliation: Department of Microbiology, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Hin
authors.initials: H
authors.lastname: Chu
authors.affiliation: School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Kailash
authors.initials: K
authors.lastname: Singh
authors.affiliation: Department of Microbiology, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Hanjun
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Department of Microbiology, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Zhang
authors.affiliation: Department of Microbiology, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Richard Y T
authors.initials: RY
authors.lastname: Kao
authors.affiliation: School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Billy K C
authors.initials: BK
authors.lastname: Chow
authors.affiliation: Department of Microbiology, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Department of Microbiology, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Bo-Jian
authors.initials: BJ
authors.lastname: Zheng
mesh_terms: D000281:Administration, Intranasal; D000818:Animals; D000998:Antiviral Agents / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D004353:Drug Evaluation, Preclinical; D004357:Drug Synergism; D005260:Female; D009980:Influenza A virus / Q000187:drug effects* / Q000201:enzymology* / Q000502:physiology; D008168:Lung / Q000821:virology; D008807:Mice, Inbred BALB C; D009976:Orthomyxoviridae Infections / Q000473:pathology / Q000517:prevention & control / Q000821:virology; D012324:RNA-Dependent RNA Polymerase / Q000037:antagonists & inhibitors*; D016019:Survival Analysis; D016896:Treatment Outcome; D019562:Viral Load; D014764:Viral Proteins / Q000037:antagonists & inhibitors*; D014779:Virus Replication / Q000187:drug effects*
chemical_list: D000998:Antiviral Agents; C061290:PA protein, influenza viruses; D014764:Viral Proteins; D012324:RNA-Dependent RNA Polymerase