title: An M2-V27A channel blocker demonstrates potent in vitro and in vivo antiviral activities against amantadine-sensitive and -resistant influenza A viruses.
abstract: Adamantanes such as amantadine (1) and rimantadine (2) are FDA-approved anti-influenza drugs that act by inhibiting the wild-type M2 proton channel from influenza A viruses, thereby inhibiting the uncoating of the virus. Although adamantanes have been successfully used for more than four decades, their efficacy was curtailed by emerging drug resistance. Among the limited number of M2 mutants that confer amantadine resistance, the M2-V27A mutant was found to be the predominant mutant under drug selection pressure, thereby representing a high profile antiviral drug target. Guided by molecular dynamics simulations, we previously designed first-in-class M2-V27A inhibitors. One of the potent lead compounds, spiroadamantane amine (3), inhibits both the M2-WT and M2-V27A mutant with IC50values of 18.7 and 0.3 μM, respectively, in in vitro electrophysiological assays. Encouraged by these findings, in this study we further examine the in vitro and in vivo antiviral activity of compound 3 in inhibiting both amantadine-sensitive and -resistant influenza A viruses. Compound 3 not only had single to sub-micromolar EC50values against M2-WT- and M2-V27A-containing influenza A viruses in antiviral assays, but also rescued mice from lethal viral infection by either M2-WT- or M2-V27A-containing influenza A viruses. In addition, we report the design of two analogs of compound 3, and one was found to have improved in vitro antiviral activity over compound 3. Collectively, this study represents the first report demonstrating the in vivo antiviral efficacy of inhibitors targeting M2 mutants. The results suggest that inhibitors targeting drug-resistant M2 mutants are promising antiviral drug candidates worthy of further development.
authors.affiliation: Department of Pharmacology and Toxicology, College of Pharmacy, The University of Arizona, Tucson, Arizona 85721, United States.
authors.forename: Yanmei
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721, United States.
authors.forename: Rami
authors.initials: R
authors.lastname: Musharrafieh
authors.affiliation: BIO5 Institute, The University of Arizona, Tucson, Arizona 85721, United States.
authors.forename: Chunlong
authors.initials: C
authors.lastname: Ma
authors.affiliation: Department of Pharmacology and Toxicology, College of Pharmacy, The University of Arizona, Tucson, Arizona 85721, United States.
authors.forename: Jiantao
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Institute for Antiviral Research, Department of Animal, Dairy and Veterinary Sciences, Utah State University, Logan, Utah 84322, United States.
authors.forename: Donald F
authors.initials: DF
authors.lastname: Smee
authors.affiliation: Department of Pharmaceutical Chemistry, School of Pharmacy, University of California, San Francisco, California 94158, United States.
authors.forename: William F
authors.initials: WF
authors.lastname: DeGrado
authors.affiliation: Department of Pharmacology and Toxicology, College of Pharmacy, The University of Arizona, Tucson, Arizona 85721, United States.|BIO5 Institute, The University of Arizona, Tucson, Arizona 85721, United States.
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
mesh_terms: D000218:Adamantane / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D000547:Amantadine / Q000494:pharmacology*; D000818:Animals; D000998:Antiviral Agents / Q000737:chemistry / Q000494:pharmacology*; D004285:Dogs; D024882:Drug Resistance, Viral; D006801:Humans; D009980:Influenza A virus / Q000187:drug effects*; D007251:Influenza, Human / Q000188:drug therapy; D020128:Inhibitory Concentration 50; D061985:Madin Darby Canine Kidney Cells; D056004:Molecular Dynamics Simulation; D009154:Mutation; D009976:Orthomyxoviridae Infections / Q000188:drug therapy; D013141:Spiro Compounds / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D014763:Viral Matrix Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics*; D000086082:Viroporin Proteins
chemical_list: D000218:Adamantane; D000547:Amantadine; D000998:Antiviral Agents; D013141:Spiro Compounds; D014763:Viral Matrix Proteins; C488937:M2 protein, Influenza A virus; D000086082:Viroporin Proteins; C000625581:spiroadamantane amine
keywords: Antiviral; Drug resistance; Influenza virus; M2 proton channel; Spiroadamantane; V27A