title: Design and pharmacological characterization of inhibitors of amantadine-resistant mutants of the M2 ion channel of influenza A virus.
abstract: The A/M2 proton channel of influenza A virus is a target for the anti-influenza drugs amantadine and rimantadine, whose effectiveness was diminished by the appearance of naturally occurring point mutants in the A/M2 channel pore, among which the most common are S31N, V27A, and L26F. We have synthesized and characterized the properties of a series of compounds, originally derived from the A/M2 inhibitor BL-1743. A lead compound emerging from these investigations, spiro[5.5]undecan-3-amine, is an effective inhibitor of wild-type A/M2 channels and L26F and V27A mutant ion channels in vitro and also inhibits replication of recombinant mutant viruses bearing these mutations in plaque reduction assays. Differences in the inhibition kinetics between BL-1743, known to bind inside the A/M2 channel pore, and amantadine were exploited to demonstrate competition between these compounds, consistent with the conclusion that amantadine binds inside the channel pore. Inhibition by all of these compounds was shown to be voltage-independent, suggesting that their charged groups are within the N-terminal half of the pore, prior to the selectivity filter that defines the region over which the transmembrane potential occurs. These findings not only help to define the location and mechanism of binding of M2 channel-blocking drugs but also demonstrate the feasibility of discovering new inhibitors that target this binding site in a number of amantadine-resistant mutants.
authors.affiliation: Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois 60208-3500, USA.
authors.forename: Victoria
authors.initials: V
authors.lastname: Balannik
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.forename: Yuki
authors.initials: Y
authors.lastname: Ohigashi
authors.forename: Xianghong
authors.initials: X
authors.lastname: Jing
authors.forename: Emma
authors.initials: E
authors.lastname: Magavern
authors.forename: Robert A
authors.initials: RA
authors.lastname: Lamb
authors.forename: William F
authors.initials: WF
authors.lastname: Degrado
authors.forename: Lawrence H
authors.initials: LH
authors.lastname: Pinto
mesh_terms: D000547:Amantadine / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D000998:Antiviral Agents / Q000138:chemical synthesis* / Q000378:metabolism / Q000494:pharmacology*; D001667:Binding, Competitive / Q000235:genetics; D002460:Cell Line; D004285:Dogs; D016503:Drug Delivery Systems; D024882:Drug Resistance, Viral / Q000235:genetics; D007093:Imidazoles / Q000494:pharmacology; D009980:Influenza A virus / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D007473:Ion Channels / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D009865:Oocytes; D017354:Point Mutation; D013141:Spiro Compounds / Q000138:chemical synthesis / Q000494:pharmacology; D014763:Viral Matrix Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D014981:Xenopus; D000086082:Viroporin Proteins
chemical_list: D000547:Amantadine; D000998:Antiviral Agents; D007093:Imidazoles; D007473:Ion Channels; D013141:Spiro Compounds; D014763:Viral Matrix Proteins; C100337:2-(3-azaspiro(5,5)undecanol)-2-imidazoline; C488937:M2 protein, Influenza A virus; D000086082:Viroporin Proteins