title: Highly sulfated K5 Escherichia coli polysaccharide derivatives inhibit respiratory syncytial virus infectivity in cell lines and human tracheal-bronchial histocultures.
abstract: Respiratory syncytial virus (RSV) exploits cell surface heparan sulfate proteoglycans (HSPGs) as attachment receptors. The interaction between RSV and HSPGs thus presents an attractive target for the development of novel inhibitors of RSV infection. In this study, selective chemical modification of the Escherichia coli K5 capsular polysaccharide was used to generate a collection of sulfated K5 derivatives with a backbone structure that mimics the heparin/heparan sulfate biosynthetic precursor. The screening of a series of N-sulfated (K5-NS), O-sulfated (K5-OS), and N,O-sulfated (K5-N,OS) derivatives with different degrees of sulfation revealed the highly sulfated K5 derivatives K5-N,OS(H) and K5-OS(H) to be inhibitors of RSV. Their 50% inhibitory concentrations were between 1.07 nM and 3.81 nM in two different cell lines, and no evidence of cytotoxicity was observed. Inhibition of RSV infection was maintained in binding and attachment assays but not in preattachment assays. Moreover, antiviral activity was also evident when the K5 derivatives were added postinfection, both in cell-to-cell spread and viral yield reduction assays. Finally, both K5-N,OS(H) and K5-OS(H) prevented RSV infection in human-derived tracheal/bronchial epithelial cells cultured to form a pseudostratified, highly differentiated model of the epithelial tissue of the human respiratory tract. Together, these features put K5-N,OS(H) and K5-OS(H) forward as attractive candidates for further development as RSV inhibitors.
authors.affiliation: Department of Clinical and Biological Sciences, University of Turin, Turin, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Cagno
authors.affiliation: Department of Clinical and Biological Sciences, University of Turin, Turin, Italy.
authors.forename: Manuela
authors.initials: M
authors.lastname: Donalisio
authors.affiliation: Department of Clinical and Biological Sciences, University of Turin, Turin, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Civra
authors.affiliation: Department of Oncology, University of Turin, Turin, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Volante
authors.affiliation: Glycores 2000 Srl, Milan, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Veccelli
authors.affiliation: Glycores 2000 Srl, Milan, Italy.
authors.forename: Pasqua
authors.initials: P
authors.lastname: Oreste
authors.affiliation: Department of Biomedical Sciences and Biotechnology, University of Brescia, Brescia, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Rusnati
authors.affiliation: Department of Clinical and Biological Sciences, University of Turin, Turin, Italy david.lembo@unito.it.
authors.forename: David
authors.initials: D
authors.lastname: Lembo
mesh_terms: D000998:Antiviral Agents / Q000302:isolation & purification / Q000494:pharmacology*; D016667:Bacterial Capsules / Q000737:chemistry*; D001980:Bronchi / Q000187:drug effects / Q000821:virology; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000187:drug effects / Q000473:pathology / Q000821:virology; D004926:Escherichia coli / Q000737:chemistry; D015726:Giant Cells / Q000187:drug effects / Q000648:ultrastructure; D006493:Heparin / Q000494:pharmacology; D006801:Humans; D011135:Polysaccharides, Bacterial / Q000302:isolation & purification / Q000494:pharmacology*; D018113:Respiratory Syncytial Virus, Human / Q000187:drug effects* / Q000502:physiology; D046509:Tissue Culture Techniques; D014132:Trachea / Q000187:drug effects / Q000821:virology; D019562:Viral Load / Q000187:drug effects; D010948:Viral Plaque Assay; D053585:Virus Attachment / Q000187:drug effects*; D014779:Virus Replication / Q000187:drug effects
chemical_list: D000998:Antiviral Agents; D011135:Polysaccharides, Bacterial; C050673:capsular polysaccharide K5; D006493:Heparin