title: Block of vesicular stomatitis virus endocytic and exocytic pathways by 1-cinnamoyl-3,11-dihydroxymeliacarpin, a tetranortriterpenoid of natural origin.
abstract: Previously, it has been shown that 1-cinnamoyl-3,11-dihydroxymeliacarpin (CDM), a natural compound isolated from leaf extracts of Melia azedarach L., inhibits the vesicular stomatitis virus (VSV) multiplication cycle when added before or after infection. Here, we have established that the lack of VSV protein synthesis in CDM pre-treated Vero cells is ascribed to the inhibition of an initial step during virus multiplication, although indirect immunofluorescence (IFI) studies confirmed that the binding and uptake of [(35)S]methionine-labelled VSV was not affected by CDM pre-treatment. Instead, our findings revealed that this compound impedes the uncoating of VSV nucleocapsids in pre-treated Vero cells, since the antiviral action of CDM was partially reversed by inducing VSV direct fusion at the plasma membrane, and VSV M protein fluorescence was confined to the endosomes, even 2 h post-internalization. Furthermore, CDM induced cytoplasmic alkalinization, as shown by acridine orange staining, consistent with the inhibition of virus uncoating. Although VSV proteins are synthesized when CDM is added after infection, IFI studies revealed that G protein was absent from the surface of infected cells and co-localized with a Golgi marker. Therefore, CDM inhibits the transport of G protein to the plasma membrane. Taken together, these findings indicate that CDM exerts its antiviral action on the endocytic and exocytic pathways of VSV by pre- or post-treatment, respectively.
authors.affiliation: Laboratory of Virology, Department of Biochemistry, School of Science, University of Buenos Aires, Pabellón II, Piso 4to, Ciudad Universitaria, C1428BGA Buenos Aires, Argentina.
authors.forename: Andrea A
authors.initials: AA
authors.lastname: Barquero
authors.affiliation: Laboratory of Virology, Department of Biochemistry, School of Science, University of Buenos Aires, Pabellón II, Piso 4to, Ciudad Universitaria, C1428BGA Buenos Aires, Argentina.
authors.forename: Laura E
authors.initials: LE
authors.lastname: Alché
authors.affiliation: Laboratory of Virology, Department of Biochemistry, School of Science, University of Buenos Aires, Pabellón II, Piso 4to, Ciudad Universitaria, C1428BGA Buenos Aires, Argentina.
authors.forename: Celia E
authors.initials: CE
authors.lastname: Coto
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D002462:Cell Membrane / Q000378:metabolism; D002522:Chlorocebus aethiops; D006863:Hydrogen-Ion Concentration; D036701:Limonins / Q000494:pharmacology*; D008562:Membrane Glycoproteins / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects; D014709:Vero Cells; D014721:Vesicular stomatitis Indiana virus / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D014759:Viral Envelope Proteins / Q000378:metabolism; D014763:Viral Matrix Proteins / Q000378:metabolism; D014779:Virus Replication / Q000187:drug effects*
chemical_list: C474472:1-cinnamoyl-3,11-dihydroxymeliacarpin; D000998:Antiviral Agents; C028391:G protein, vesicular stomatitis virus; D036701:Limonins; C094460:M protein, Vesicular stomatitis virus; D008562:Membrane Glycoproteins; D014759:Viral Envelope Proteins; D014763:Viral Matrix Proteins