Modulation of translational elongation by montanine alkaloids preferentially inhibits RNA viruses

Abstract

Montanine, an Amaryllidaceae alkaloid, has demonstrated superior antiviral activity against dengue virus (DENV), SARS-CoV-2, vesicular stomatitis Indiana virus (VSV-G), and vesicular stomatitis virus pseudotyped with Ebola virus glycoprotein (VSV-ZGP), outperforming other antiviral alkaloids tested, including lycorine, narciclasine, tetracetylnarciclasine, and pancracine. We further showed that montanine inhibits translation in mammalian cells, as evidenced by a puromycin incorporation assay. Cryo-EM analysis revealed that montanine binds to the peptidyl transferase center of the human ribosome. A chemical genomics survey indicated that the knockdown of the GCN1 complex, which senses ribosome collisions and triggers the translation quality control process, increased the cytotoxicity of montanine while reducing viral infectivity. Together, these results suggest that the antiviral activity of montanine is closely linked to its impact on translational elongation and GCN1-related stress responses, underscoring the potential of translation control as a targeted mode for RNA virus therapeutics. Significance StatementMontanine, an alkaloid from the Amaryllidaceae family known for its diverse bioactivities, was identified as a potent antiviral compound from a library of natural plant- and fungus-derived substances. Through a combination of biochemical assays and cryo-EM analysis, we discovered that montanine binds to the peptidyl transfer center of the human ribosome, effectively inhibiting protein synthesis. Based on these findings and a chemical genomics approach, we hypothesize that the translational control of montanine triggers a cellular response that impedes viral replication. We propose that molecules capable of modulating translation efficacy could serve as unique lead compounds in the development of broad-spectrum antiviral agents.