title: Mutations in the chikungunya virus non-structural proteins cause resistance to favipiravir (T-705), a broad-spectrum antiviral.
abstract: OBJECTIVE
  T-705, also known as favipiravir, is a small-molecule inhibitor that is currently in clinical development for the treatment of influenza virus infections. This molecule also inhibits the replication of a broad spectrum of other RNA viruses. The objective of this study was to investigate the antiviral effect of favipiravir on chikungunya virus (CHIKV) replication and to contribute to unravelling the molecular mechanism of action against this virus.
  
  
  METHODS
  The anti-CHIKV effect of favipiravir was examined in cell culture and in a mouse model of lethal infection. A five-step protocol was used to select for CHIKV variants with reduced susceptibility to favipiravir. The resistant phenotype was confirmed in cell culture and the whole genome was sequenced. The identified mutations were reverse-engineered into an infectious clone to confirm their impact on the antiviral efficacy of favipiravir.
  
  
  RESULTS
  Favipiravir inhibits the replication of laboratory strains and clinical isolates of CHIKV, as well as of a panel of other alphaviruses. Several favipiravir-resistant CHIKV variants were independently selected and all of them in particular acquired the unique K291R mutation in the RNA-dependent RNA polymerase (RdRp). Reverse-engineering of this K291R mutation into an infectious clone of CHIKV confirmed the link between the mutant genotype and the resistant phenotype. Interestingly, this particular lysine is also highly conserved in the RdRp of positive-stranded RNA viruses in general.
  
  
  CONCLUSIONS
  This study provides an important insight into the precise molecular mechanism by which favipiravir exerts its antiviral activity against (alpha)viruses, which may be of help in designing other potent broad-spectrum antivirals.
authors.affiliation: Laboratory for Virology and Experimental Chemotherapy, Rega Institute for Medical Research, KU Leuven, Minderbroedersstraat 10, 3000 Leuven, Belgium.
authors.forename: Leen
authors.initials: L
authors.lastname: Delang
authors.affiliation: Laboratory for Virology and Experimental Chemotherapy, Rega Institute for Medical Research, KU Leuven, Minderbroedersstraat 10, 3000 Leuven, Belgium Laboratorio de Entomología Médica, Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Calle 63D 24-31, Bogotá DC, Colombia.
authors.forename: Nidya
authors.initials: N
authors.lastname: Segura Guerrero
authors.affiliation: Molecular Virology Laboratory, Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Ali
authors.initials: A
authors.lastname: Tas
authors.affiliation: UMR_D 190 "Emergence des Pathologies Virales" (Aix-Marseille University, IRD French Institute of Research for Development, EHESP French School of Public Health), Marseille, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Quérat
authors.affiliation: UMR_D 190 "Emergence des Pathologies Virales" (Aix-Marseille University, IRD French Institute of Research for Development, EHESP French School of Public Health), Marseille, France.
authors.forename: Boris
authors.initials: B
authors.lastname: Pastorino
authors.affiliation: Laboratory for Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Minderbroedersstraat 10, 3000 Leuven, Belgium.
authors.forename: Mathy
authors.initials: M
authors.lastname: Froeyen
authors.affiliation: Laboratory for Virology and Experimental Chemotherapy, Rega Institute for Medical Research, KU Leuven, Minderbroedersstraat 10, 3000 Leuven, Belgium.
authors.forename: Kai
authors.initials: K
authors.lastname: Dallmeier
authors.affiliation: Laboratory for Virology and Experimental Chemotherapy, Rega Institute for Medical Research, KU Leuven, Minderbroedersstraat 10, 3000 Leuven, Belgium.
authors.forename: Dirk
authors.initials: D
authors.lastname: Jochmans
authors.affiliation: Laboratory for Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Minderbroedersstraat 10, 3000 Leuven, Belgium.
authors.forename: Piet
authors.initials: P
authors.lastname: Herdewijn
authors.affiliation: Laboratorio de Entomología Médica, Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Calle 63D 24-31, Bogotá DC, Colombia.
authors.forename: Felio
authors.initials: F
authors.lastname: Bello
authors.affiliation: Molecular Virology Laboratory, Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Snijder
authors.affiliation: UMR_D 190 "Emergence des Pathologies Virales" (Aix-Marseille University, IRD French Institute of Research for Development, EHESP French School of Public Health), Marseille, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: de Lamballerie
authors.affiliation: Department of Viroscience, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Byron
authors.initials: B
authors.lastname: Martina
authors.affiliation: Laboratory for Virology and Experimental Chemotherapy, Rega Institute for Medical Research, KU Leuven, Minderbroedersstraat 10, 3000 Leuven, Belgium johan.neyts@rega.kuleuven.be.
authors.forename: Johan
authors.initials: J
authors.lastname: Neyts
authors.affiliation: Molecular Virology Laboratory, Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Martijn J
authors.initials: MJ
authors.lastname: van Hemert
authors.affiliation: Laboratory for Virology and Experimental Chemotherapy, Rega Institute for Medical Research, KU Leuven, Minderbroedersstraat 10, 3000 Leuven, Belgium.
authors.forename: Pieter
authors.initials: P
authors.lastname: Leyssen
mesh_terms: D000577:Amides / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D000998:Antiviral Agents / Q000737:chemistry / Q000494:pharmacology*; D002460:Cell Line; D065632:Chikungunya Fever / Q000188:drug therapy / Q000821:virology; D002646:Chikungunya virus / Q000187:drug effects* / Q000235:genetics*; D003588:Cytopathogenic Effect, Viral / Q000187:drug effects; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D024882:Drug Resistance, Viral / Q000235:genetics*; D051379:Mice; D008826:Microbial Sensitivity Tests; D009154:Mutation; D010641:Phenotype; D011719:Pyrazines / Q000737:chemistry / Q000494:pharmacology*; D015203:Reproducibility of Results; D017361:Viral Nonstructural Proteins / Q000235:genetics*; D014779:Virus Replication / Q000187:drug effects
chemical_list: D000577:Amides; D000998:Antiviral Agents; D011719:Pyrazines; D017361:Viral Nonstructural Proteins; C462182:favipiravir
keywords: alphavirus; nsP4; polymerase