title: The proton translocation domain of cellular vacuolar ATPase provides a target for the treatment of influenza A virus infections.
abstract: OBJECTIVE
  Cellular vacuolar ATPases (v-ATPase) play an important role in endosomal acidification, a critical step in influenza A virus (IAV) host cell infection. We investigated the antiviral activity of the v-ATPase inhibitor saliphenylhalamide (SaliPhe) and compared it with several older v-ATPase inhibitors concanamycin A, bafilomycin A1, (BafA) and archazolid B targeting the subunit c of the V(0) sector.
  
  
  METHODS
  An in vitro assay was devised to quantify the anti-influenza effect of v-ATPase inhibitors by measuring green fluorescent protein fluorescence of a reporter IAV. These data were combined with cytotoxicity testing to calculate selectivity indices. Data were validated by testing v-ATPase inhibitors against wild-type IAV in vitro and in vivo in mice.
  
  
  RESULTS
  In vitro SaliPhe blocked the proliferation of pandemic and multidrug resistant viruses at concentrations up to 51-fold below its cytotoxic concentrations. At essentially non-toxic concentrations, SaliPhe protected 62.5% of mice against a lethal challenge of a mouse-adapted influenza strain, while BafA at cytotoxic concentrations showed essentially no protection against infection with IAV (SaliPhe vs. BafA P < 0.001).
  
  
  CONCLUSIONS
  Our results show that a distinct binding site of the proton translocation domain of cellular v-ATPase can be selectively targeted by a new generation v-ATPase inhibitor with reduced toxicity to treat influenza virus infections, including multi-resistant strains. Treatment strategies against influenza that target host cellular proteins are expected to be more resistant to virus mutations than drugs blocking viral proteins.
authors.affiliation: Institute of Immunology, Centre de Recherche Public-Santé/Laboratoire National de Santé, Luxembourg, Luxembourg. Claude.Muller@LNS.ETAT.LU
authors.forename: Konstantin H
authors.initials: KH
authors.lastname: Müller
authors.forename: Denis E
authors.initials: DE
authors.lastname: Kainov
authors.forename: Karim
authors.initials: K
authors.lastname: El Bakkouri
authors.forename: Xavier
authors.initials: X
authors.lastname: Saelens
authors.forename: Jef K
authors.initials: JK
authors.lastname: De Brabander
authors.forename: Christian
authors.initials: C
authors.lastname: Kittel
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Samm
authors.forename: Claude P
authors.initials: CP
authors.lastname: Muller
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000737:chemistry / Q000494:pharmacology*; D002460:Cell Line; D004285:Dogs; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology; D049452:Green Fluorescent Proteins / Q000378:metabolism; D053118:Influenza A Virus, H1N1 Subtype; D051379:Mice; D008807:Mice, Inbred BALB C; D015394:Molecular Structure; D009976:Orthomyxoviridae Infections / Q000188:drug therapy* / Q000821:virology; D017434:Protein Structure, Tertiary; D013997:Time Factors; D025262:Vacuolar Proton-Translocating ATPases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D014779:Virus Replication / Q000187:drug effects
chemical_list: D000998:Antiviral Agents; D004791:Enzyme Inhibitors; D049452:Green Fluorescent Proteins; D025262:Vacuolar Proton-Translocating ATPases