Inactivation of arenavirus infection by aromatic difulfides

SEPÚLVEDA, C.S.; GARCÍA, C. C.; LEVINGSTON MCLEOD, J.M.; LÓPEZ, N.; DAMONTE, E.B.

Sapporo

Conferencia; 25th International Conference on Antiviral Research,; 2012

Arenaviruses are enveloped viruses containing a bipartite, single-stranded RNA genome, with ambisense coding strategy. Five arenaviruses cause severe hemorrhagic fevers in humans, but at present no reliable drug therapy is available. The presence in arenaviruses of the Z protein, containing a highly conserved RING finger motif, prompted us to initiate studies about this protein as a possible target for a new viral inhibitory strategy. We have previously shown that antiretroviral compounds with diverse chemical structures, kindly provided by the National Cancer Institute (USA), which target to the Zn-finger motifs in the HIV nucleocapsid protein NCp7, display antiviral and virucidal activity against arenaviruses. Here, the in vitro inhibitory activity of a selected group of aromatic disulfides with diverse substitutions is reported. The carboxamide-derivatized disulfide NSC4492 and the amino-nitro-derivative NSC71033 demonstrated moderate antiviral activity against the pathogenic arenavirus Junín (JUNV) as determined by virus yield inhibition assay in Vero cells, with values of antiviral effective concentration 50% (EC50) in the range 27.7-32.4 µM, but a very potent virucidal effect, with inactivating concentration 50% (IC50) in the range 0.2-0.5 µM. NSC4492 inactivated diverse arenaviruses, with a linear kinetics of reaction in a temperature dependent form. In addition, the activity spectrum of these disulfides also included viruses from other families, but the reactivity was greater against those viral agents containing RING finger motifs like JUNV. Mechanistic studies demonstrated that viral RNA synthesis was blocked after infection of Vero cells with inactivated JUNV virions, with subsequent inhibition of viral protein expression. Furthermore, the interaction of the disulfide with JUNV Z protein was determined by Western blot analysis of virus-like particles released into the supernatants from cells expressing an HA-tagged version of Junin virus Z protein in presence of NSC4492. An alteration in the electrophoretic profile of Z oligomers was observed, suggesting that the compound might induce conformational change in Z protein.