Broad-spectrum antiviral ferruginol analog affects the viral proteins translation and actin remodeling during dengue virus infection

Dengue virus infection is the most important arbovirosis around the world. To date, no antiviral drugs have been approved for its treatment. Host-targeted antivirals (HTA) have emerged as a promising strategy, because of their high barrier to resistance. Using plaque-forming unit assays, molecular docking, fluorescence microscopy, image analysis, and molecular/cellular assays, it was found that 18-(phthalimide-2-yl)-ferruginol, a semi-synthetic analog of the bioactive diterpenoid ferruginol, couples with high affinity to RhoA GTPase. In addition, this molecule dramatically reduced actin filament formation and induced cellular morphological changes, when added to cell cultures before or after infection, without effect on microtubules or intermediate filaments. RhoA activation in infected cells was affected when the compound was added after 6 h.p.i. Furthermore, this compound decreased dengue virus-2 (DENV-2) E protein, NS3 protein, and dsRNA as measured by fluorescence microscopy, and changes in the distribution pattern of these viral components. 18-(phthalimide-2-yl)-ferruginol treatment at 6 and 12 h.p.i. reduces the virus yield. Western blot and RT-qPCR assays reveal that this analog decreased viral protein translation. Flow cytometry and wound-healing experiments also hint that cellular effects prompted for this compound do not relate to early apoptotic events and they could be reversible. Overall, our findings strongly suggest that 18-(phthalimide-2-yl)-ferruginol has an HTA mechanism, possibly disrupting the polyprotein translation of DENV-2 via alteration of RhoA-mediated actin remodeling and other related cellular and viral processes.