NAT10 is critical to block RNA sensing-induced IFN-β transactivation in viral infection.

Cells detect invading viruses and produce type I interferons (IFNs) to stimulate an innate antiviral effector response. However, IFN levels must be fine-tuned to achieve antiviral efficacy while limiting hyperinflammatory and tissue-damaging effects. Here, we report that NAT10, a histone and cytidine acetyltransferase, regulates the production of type I IFNs and RNA virus infections. Depletion of NAT10 increased the expression of IFN-β and IFN-stimulated genes, and correspondingly impaired viral replication. Mechanistically, NAT10 dynamically associated with the IFN-β promoter and also negatively regulated IRF3's chromatin associations through modulation of long noncoding RNAs that inhibit IRF3. Treatment of cells with Remodelin, a NAT10 inhibitor, similarly increased IFN-β expression and inhibited viral infections. Overall, our findings reveal NAT10 is a potential host-directed target for antiviral treatment via regulation of type I IFN. IMPORTANCE: Type I interferons (IFNs) signaling pathway is critical to cellular defense and innate immunity against evading pathogens, including viruses. However, induction of type I IFNs is fine-tuned to achieve the antiviral consequence while maintaining host cellular homeostasis. This paper presents a novel mechanism for the NAT10 protein to silence IFN-β induction through modulation of IRF3 activity at the promoter of IFN-β, and further demonstrates the therapeutic potential of the NAT10 inhibitor Remodelin to restrict viral infection while inducing IFN-β.