title: The intracellular inhibition of HCV replication represents a novel mechanism of action by the innate immune Lactoferrin protein.
abstract: Hepatitis C virus (HCV) is a major public-health problem with 130-170 million individuals chronically infected worldwide. In order to halt the epidemic, therapy against HCV will need to be both effective and widely available. Studies focusing on safe and affordable natural product active against HCV have revealed the antiviral activity of the human Lactoferrin (hLF) protein which binds and neutralizes the circulating virion. In the current study, investigation of hLF activity on the HCV subgenomic replicon system, which is independent from viral entry and shedding, revealed a distinct antireplicative activity of hLF against HCV. Hepatocellular uptake of hLF was confirmed and correlated with qualitative HCV staining reduction. Quantitative dose-response inhibition assays confirmed an hLF-mediated and dose-dependent HCV replication reduction reaching up to 60%. The in cellulo anti-HCV activity of hLF was additive to both Ribavirin and Interferon-α-2b. Further investigation of hLF activity against the essential viral proteins involved in HCV genome replication revealed an inhibitory activity against the HCV ATPase/Helicase NS3 protein but not against the HCV RNA-dependent RNA polymerase (NS5B protein). NS3 inhibition was mediated by a direct and specific interaction between hLF and an allosteric binding site on NS3. Taken together, our findings reveal a new antiviral mechanism of action by which hLF inhibits intracellular HCV replication.
authors.affiliation: Département de Biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Picard-Jean
authors.affiliation: Département de Biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Bouchard
authors.affiliation: Département de Biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada.
authors.forename: Geneviève
authors.initials: G
authors.lastname: Larivée
authors.affiliation: Département de Biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada. Electronic address: Martin.Bisaillon@USherbrooke.ca.
authors.forename: Martin
authors.initials: M
authors.lastname: Bisaillon
mesh_terms: D000495:Allosteric Site; D016174:Hepacivirus / Q000201:enzymology / Q000235:genetics / Q000502:physiology*; D006526:Hepatitis C / Q000276:immunology* / Q000821:virology; D006801:Humans; D007113:Immunity, Innate; D007781:Lactoferrin / Q000737:chemistry / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D011485:Protein Binding; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014779:Virus Replication; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D007781:Lactoferrin; D017361:Viral Nonstructural Proteins; C490098:LTF protein, human; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
keywords: ATPase/Helicase; Hepatitis C virus (HCV); Human Lactoferrin (hLF); Inhibitor; NS3; Viral replication