Statins attenuate antiviral IFN- and ISG expression via inhibiting IRF3/JAK/STAT signaling in poly(I:C)-treated hyperlipidemic mice and macrophages
Viral infection is a significant burden to healthcare worldwide. Statins, 3-hydroxy-3-methyl glutaryl coenzyme A reductase inhibitors, are widely used as cholesterol-lowering drugs. Recently, long term statin therapy was shown to reduce the antiviral immune response; however, the underlying molecular mechanisms are unclear. Here, we found that simvastatin decreased polyinosinic-polycytidylic acid [poly(I:C)]-induced expression of antiviral interferon (IFN)-{beta} and IFN-stimulated genes (ISGs) in the bronchoalveolar lavage fluid and lungs of mice with high-fat diet-induced hyperlipidemia. As macrophages were the dominant cell type in the bronchoalveolar lavage fluid of poly(I:C)-treated mice, we examined the molecular mechanisms of statin-mediated inhibition of antiviral gene expression using murine J774.1/JA-4 macrophages. Simvastatin and pitavastatin decreased poly(I:C)-induced expression of IFN-{beta} and ISGs. Moreover, they repressed poly(I:C)-induced phosphorylation of IFN regulatory factor (IRF) 3 and signal transducers and activators of transcription (STAT) 1, which is involved in Janus kinase (JAK)/STAT signaling. Mevalonate and geranylgeranylpyrophosphate (GGPP), but not cholesterol, counteracted the negative effect of statins on IFN-{beta} and ISG expression and phosphorylation of IRF3 and STAT1. These results suggest that statins suppressed the expression of IFN-{beta} and ISGs in poly(I:C)-treated hyperlipidemic mice and murine macrophages, and that these effects occured through the inhibition of IRF3-mediated JAK/STAT signaling in macrophages. Furthermore, GGPP recovered the statin-suppressed IRF3/JAK/STAT signaling pathway in poly(I:C)-treated macrophages.