title: Rigid amphipathic fusion inhibitors, small molecule antiviral compounds against enveloped viruses.
abstract: Antiviral drugs targeting viral proteins often result in prompt selection for resistance. Moreover, the number of viral targets is limited. Novel antiviral targets are therefore needed. The unique characteristics of fusion between virion envelopes and cell membranes may provide such targets. Like all fusing bilayers, viral envelopes locally adopt hourglass-shaped stalks during the initial stages of fusion, a process that requires local negative membrane curvature. Unlike cellular vesicles, however, viral envelopes do not redistribute lipids between leaflets, can only use the energy released by virion proteins, and fuse to the extracellular leaflets of cell membranes. Enrichment in phospholipids with hydrophilic heads larger than their hydrophobic tails in the convex outer leaflet of vesicles favors positive curvature, therefore increasing the activation energy barrier for fusion. Such phospholipids can increase the activation barrier beyond the energy provided by virion proteins, thereby inhibiting viral fusion. However, phospholipids are not pharmacologically useful. We show here that a family of synthetic rigid amphiphiles of shape similar to such phospholipids, RAFIs (rigid amphipathic fusion inhibitors), inhibit the infectivity of several otherwise unrelated enveloped viruses, including hepatitis C and HSV-1 and -2 (lowest apparent IC(50) 48 nM), with no cytotoxic or cytostatic effects (selectivity index > 3,000) by inhibiting the increased negative curvature required for the initial stages of fusion.
authors.affiliation: Department of Biochemistry, Li Ka Shing Institute of Virology, University of Alberta, Edomonton, AB, Canada.
authors.forename: Mireille R
authors.initials: MR
authors.lastname: St Vincent
authors.forename: Che C
authors.initials: CC
authors.lastname: Colpitts
authors.forename: Alexey V
authors.initials: AV
authors.lastname: Ustinov
authors.forename: Muhammad
authors.initials: M
authors.lastname: Muqadas
authors.forename: Michael A
authors.initials: MA
authors.lastname: Joyce
authors.forename: Nicola L
authors.initials: NL
authors.lastname: Barsby
authors.forename: Raquel F
authors.initials: RF
authors.lastname: Epand
authors.forename: Richard M
authors.initials: RM
authors.lastname: Epand
authors.forename: Stanislav A
authors.initials: SA
authors.lastname: Khramyshev
authors.forename: Olga A
authors.initials: OA
authors.lastname: Valueva
authors.forename: Vladimir A
authors.initials: VA
authors.lastname: Korshun
authors.forename: D Lorne J
authors.initials: DL
authors.lastname: Tyrrell
authors.forename: Luis M
authors.initials: LM
authors.lastname: Schang
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D002460:Cell Line; D002462:Cell Membrane / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D018259:Herpesvirus 1, Human / Q000187:drug effects / Q000472:pathogenicity / Q000648:ultrastructure; D006801:Humans; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D008563:Membrane Lipids / Q000378:metabolism; D015394:Molecular Structure; D014764:Viral Proteins / Q000378:metabolism*; D014771:Virion / Q000378:metabolism / Q000472:pathogenicity / Q000648:ultrastructure; D053586:Virus Internalization / Q000187:drug effects*; D014780:Viruses / Q000187:drug effects* / Q000472:pathogenicity / Q000648:ultrastructure
chemical_list: D000998:Antiviral Agents; D008051:Lipid Bilayers; D008563:Membrane Lipids; D014764:Viral Proteins; C050629:viral envelope lipids
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