title: Novel inhibitors of severe acute respiratory syndrome coronavirus entry that act by three distinct mechanisms.
abstract: Severe acute respiratory syndrome (SARS) is an infectious and highly contagious disease that is caused by SARS coronavirus (SARS-CoV) and for which there are currently no approved treatments. We report the discovery and characterization of small-molecule inhibitors of SARS-CoV replication that block viral entry by three different mechanisms. The compounds were discovered by screening a chemical library of compounds for blocking of entry of HIV-1 pseudotyped with SARS-CoV surface glycoprotein S (SARS-S) but not that of HIV-1 pseudotyped with vesicular stomatitis virus surface glycoprotein G (VSV-G). Studies on their mechanisms of action revealed that the compounds act by three distinct mechanisms: (i) SSAA09E2 {N-[[4-(4-methylpiperazin-1-yl)phenyl]methyl]-1,2-oxazole-5-carboxamide} acts through a novel mechanism of action, by blocking early interactions of SARS-S with the receptor for SARS-CoV, angiotensin converting enzyme 2 (ACE2); (ii) SSAA09E1 {[(Z)-1-thiophen-2-ylethylideneamino]thiourea} acts later, by blocking cathepsin L, a host protease required for processing of SARS-S during viral entry; and (iii) SSAA09E3 [N-(9,10-dioxo-9,10-dihydroanthracen-2-yl)benzamide] also acts later and does not affect interactions of SARS-S with ACE2 or the enzymatic functions of cathepsin L but prevents fusion of the viral membrane with the host cellular membrane. Our work demonstrates that there are at least three independent strategies for blocking SARS-CoV entry, validates these mechanisms of inhibition, and introduces promising leads for the development of SARS therapeutics.
authors.affiliation: Christopher S. Bond Life Sciences Center, Department of Molecular Microbiology and Immunology, University of Missouri School of Medicine, Columbia, Missouri, USA.
authors.forename: Adeyemi O
authors.initials: AO
authors.lastname: Adedeji
authors.forename: William
authors.initials: W
authors.lastname: Severson
authors.forename: Colleen
authors.initials: C
authors.lastname: Jonsson
authors.forename: Kamalendra
authors.initials: K
authors.lastname: Singh
authors.forename: Susan R
authors.initials: SR
authors.lastname: Weiss
authors.forename: Stefan G
authors.initials: SG
authors.lastname: Sarafianos
mesh_terms: D000085962:Angiotensin-Converting Enzyme 2; D000873:Anthracenes / Q000494:pharmacology*; D001549:Benzamides / Q000494:pharmacology*; D015153:Blotting, Western; D002401:Cathepsin B / Q000378:metabolism; D056668:Cathepsin L / Q000037:antagonists & inhibitors / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D005470:Fluorometry; D057809:HEK293 Cells; D006801:Humans; D047468:Immunoprecipitation; D008156:Luciferases; D010080:Oxazoles / Q000494:pharmacology*; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism; D010879:Piperazines / Q000494:pharmacology*; D060888:Real-Time Polymerase Chain Reaction; D045473:Severe acute respiratory syndrome-related coronavirus / Q000502:physiology*; D054852:Small Molecule Libraries; D013876:Thiophenes / Q000494:pharmacology*; D013890:Thiourea / Q000494:pharmacology*; D053586:Virus Internalization / Q000187:drug effects*
chemical_list: C583221:((Z)-1-thiophen-2-ylethylideneamino)thiourea; D000873:Anthracenes; D001549:Benzamides; D017931:DNA Primers; C583223:N-((4-(4-methylpiperazin-1-yl)phenyl)methyl)-1,2-oxazole-5-carboxamide; C583222:N-(9,10-dioxo-9,10-dihydroanthracen-2-yl)benzamide; D010080:Oxazoles; D010879:Piperazines; D054852:Small Molecule Libraries; D013876:Thiophenes; D008156:Luciferases; D007703:Peptidyl-Dipeptidase A; C000705307:ACE2 protein, human; D000085962:Angiotensin-Converting Enzyme 2; D002401:Cathepsin B; D056668:Cathepsin L; D013890:Thiourea