1. Identification of new benzofuran derivatives as STING agonists with broad-spectrum antiviral activity.
- Author
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Paulis, A., Onali, A., Vidalain, P.O., Lotteau, V., Jaquemin, C., Corona, A., Distinto, S., Delogu, G.L., and Tramontano, E.
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BENZOFURAN , *TYPE I interferons , *BENZIMIDAZOLES , *PROTEIN-ligand interactions , *BENZOTHIAZOLE derivatives , *BENZIMIDAZOLE derivatives , *BENZOFURANS - Abstract
• Benzofuran derivatives were shown to induce IFN-I expression in a STING-dependent luciferase assay. • Activity as STING agonist was confirmed by mutagenesis studies. • Antiviral effect of BZFs was demonstrated on HCoV-229E and SARS-CoV-2 replication. • IFN-I mediated antiviral effect was confirmed by immunofluorescent analysis. The Stimulator of Interferon Genes (STING) is involved in cytosolic DNA sensing and type I Interferons (IFN-I) induction. Aiming to identify new STING agonists with antiviral activity and given the known biological activity of benzothiazole and benzimidazole derivatives, a series of benzofuran derivatives were tested for their ability to act as STING agonists, induce IFN-I and inhibit viral replication. Compounds were firstly evaluated in a gene reporter assay measuring luciferase activity driven by the human IFN-β promoter in cells expressing exogenous STING (HEK293T). Seven of them were able to induce IFN-β transcription while no induction of the IFN promoter was observed in the presence of a mutated and inactive STING, showing specific protein-ligand interaction. Docking studies were performed to predict their putative binding mode. The best hit compounds were then tested on human coronavirus 229E replication in BEAS-2B and MRC-5 cells and three derivatives showed EC 50 values in the μM range. Such compounds were also tested on SARS-CoV-2 replication in BEAS-2B cells and in Calu-3 showing they can inhibit SARS-CoV-2 replication at nanomolar concentrations. To further confirm their IFN-dependent antiviral activity, compounds were tested to verify their effect on phospho-IRF3 nuclear localization, that was found to be induced by benzofuran derivatives, and SARS-CoV-2 replication in Vero E6 cells, lacking IFN production, founding them to be inactive. In conclusion, we identified benzofurans as STING-dependent immunostimulatory compounds and host-targeting inhibitors of coronaviruses representing a novel chemical scaffold for the development of broad-spectrum antivirals. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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