title: Polyphenols Inhibit Hepatitis C Virus Entry by a New Mechanism of Action.
abstract: Despite the validation of direct-acting antivirals for hepatitis C treatment, the discovery of new compounds with different modes of action may still be of importance for the treatment of special patient populations. We recently identified a natural molecule, epigallocatechin-3-gallate (EGCG), as an inhibitor of hepatitis C virus (HCV) targeting the viral particle. The aim of this work was to discover new natural compounds with higher anti-HCV activity than that of EGCG and determine their mode of action. Eight natural molecules with structure similarity to EGCG were selected. HCV JFH1 in cell culture and HCV pseudoparticle systems were used to determine the antiviral activity and mechanism of action of the compounds. We identified delphinidin, a polyphenol belonging to the anthocyanidin family, as a new inhibitor of HCV entry. Delphinidin inhibits HCV entry in a pangenotypic manner by acting directly on the viral particle and impairing its attachment to the cell surface. Importantly, it is also active against HCV in primary human hepatocytes, with no apparent cytotoxicity and in combination with interferon and boceprevir in cell culture. Different approaches showed that neither aggregation nor destruction of the particle occurred. Cryo-transmission electron microscopy observations of HCV pseudoparticles treated with delphinidin or EGCG showed a bulge on particles that was not observed under control conditions. In conclusion, EGCG and delphinidin inhibit HCV entry by a new mechanism, i.e., alteration of the viral particle structure that impairs its attachment to the cell surface.
  
  
  OBJECTIVE
  In this article, we identify a new inhibitor of hepatitis C virus (HCV) infection, delphinidin, that prevents HCV entry. This natural compound, a plant pigment responsible for the blue-purple color of flowers and berries, belongs to the flavonoid family, like the catechin EGCG, the major component present in green tea extract, which is also an inhibitor of HCV entry. We studied the mode of action of these two compounds against HCV and demonstrated that they both act directly on the virus, inducing a bulging of the viral envelope. This deformation might be responsible for the observed inhibition of virus attachment to the cell surface. The discovery of such HCV inhibitors with an unusual mode of action is important to better characterize the mechanism of HCV entry into hepatocytes and to help develop a new class of HCV entry inhibitors.
authors.affiliation: Center for Infection & Immunity of Lille (CIIL), Inserm U1019, CNRS UMR8204, Institut Pasteur de Lille, Université Lille Nord de France, Lille, France.
authors.forename: Noémie
authors.initials: N
authors.lastname: Calland
authors.affiliation: Center for Infection & Immunity of Lille (CIIL), Inserm U1019, CNRS UMR8204, Institut Pasteur de Lille, Université Lille Nord de France, Lille, France.
authors.forename: Marie-Emmanuelle
authors.initials: ME
authors.lastname: Sahuc
authors.affiliation: Center for Infection & Immunity of Lille (CIIL), Inserm U1019, CNRS UMR8204, Institut Pasteur de Lille, Université Lille Nord de France, Lille, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Belouzard
authors.affiliation: University Paris Descartes, EA 4474, Hepatitis C Virology, Paris, France.
authors.forename: Véronique
authors.initials: V
authors.lastname: Pène
authors.affiliation: University Bordeaux, CBMN UMR 5248, Bordeaux INP, Pessac, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Bonnafous
authors.affiliation: Department of Clinical Chemistry, Microbiology and Immunology, Ghent University, Ghent, Belgium.
authors.forename: Ahmed Atef
authors.initials: AA
authors.lastname: Mesalam
authors.affiliation: Center for Infection & Immunity of Lille (CIIL), Inserm U1019, CNRS UMR8204, Institut Pasteur de Lille, Université Lille Nord de France, Lille, France.
authors.forename: Gaspard
authors.initials: G
authors.lastname: Deloison
authors.affiliation: Virology Laboratory, EA 4294, Centre Hospitalier Universitaire d'Amiens, Université de Picardie Jules Verne, Amiens, France.
authors.forename: Véronique
authors.initials: V
authors.lastname: Descamps
authors.affiliation: Laboratory of Pharmacognosy, EA 4481, Université Lille 2, Lille, France.
authors.forename: Sevser
authors.initials: S
authors.lastname: Sahpaz
authors.affiliation: Center for Infection & Immunity of Lille (CIIL), Inserm U1019, CNRS UMR8204, Institut Pasteur de Lille, Université Lille Nord de France, Lille, France.
authors.forename: Czeslaw
authors.initials: C
authors.lastname: Wychowski
authors.affiliation: University Bordeaux, CBMN UMR 5248, Bordeaux INP, Pessac, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Lambert
authors.affiliation: Center for Infection & Immunity of Lille (CIIL), Inserm U1019, CNRS UMR8204, Institut Pasteur de Lille, Université Lille Nord de France, Lille, France.
authors.forename: Priscille
authors.initials: P
authors.lastname: Brodin
authors.affiliation: Virology Laboratory, EA 4294, Centre Hospitalier Universitaire d'Amiens, Université de Picardie Jules Verne, Amiens, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Duverlie
authors.affiliation: Department of Clinical Chemistry, Microbiology and Immunology, Ghent University, Ghent, Belgium.
authors.forename: Philip
authors.initials: P
authors.lastname: Meuleman
authors.affiliation: University Paris Descartes, EA 4474, Hepatitis C Virology, Paris, France.
authors.forename: Arielle R
authors.initials: AR
authors.lastname: Rosenberg
authors.affiliation: Center for Infection & Immunity of Lille (CIIL), Inserm U1019, CNRS UMR8204, Institut Pasteur de Lille, Université Lille Nord de France, Lille, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Dubuisson
authors.affiliation: Center for Infection & Immunity of Lille (CIIL), Inserm U1019, CNRS UMR8204, Institut Pasteur de Lille, Université Lille Nord de France, Lille, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Rouillé
authors.affiliation: Center for Infection & Immunity of Lille (CIIL), Inserm U1019, CNRS UMR8204, Institut Pasteur de Lille, Université Lille Nord de France, Lille, France karin.seron@ibl.cnrs.fr.
authors.forename: Karin
authors.initials: K
authors.lastname: Séron
mesh_terms: D000872:Anthocyanins / Q000008:administration & dosage / Q000494:pharmacology; D000998:Antiviral Agents / Q000008:administration & dosage / Q000494:pharmacology*; D002392:Catechin / Q000031:analogs & derivatives / Q000494:pharmacology; D002460:Cell Line; D020285:Cryoelectron Microscopy; D004353:Drug Evaluation, Preclinical; D057809:HEK293 Cells; D016174:Hepacivirus / Q000187:drug effects* / Q000502:physiology* / Q000648:ultrastructure; D022781:Hepatocytes / Q000187:drug effects / Q000821:virology; D006801:Humans; D016898:Interferon-alpha / Q000008:administration & dosage; D059808:Polyphenols / Q000008:administration & dosage / Q000494:pharmacology*; D011392:Proline / Q000008:administration & dosage / Q000031:analogs & derivatives; D053586:Virus Internalization / Q000187:drug effects*
chemical_list: D000872:Anthocyanins; D000998:Antiviral Agents; D016898:Interferon-alpha; D059808:Polyphenols; C512204:N-(3-amino-1-(cyclobutylmethyl)-2,3-dioxopropyl)-3-(2-((((1,1-dimethylethyl)amino)carbonyl)amino)-3,3-dimethyl-1-oxobutyl)-6,6-dimethyl-3-azabicyclo(3.1.0)hexan-2-carboxamide; D002392:Catechin; D011392:Proline; C045651:epigallocatechin gallate; C017185:delphinidin