Pseudomonas aeruginosa-induced IL-1 beta Production is Inhibited by Sophora flavescens via the NF-kappa B/inflammasome Pathways

Abstract

The proinflammatory cytokine interleukin-1 beta plays an important role in protecting the host against airway infection; however, it can also trigger a massive influx of neutrophils into the airways, causing tissue damage. Anti-inflammatory treatments are particularly in demand for patients suffering from chronic inflammatory diseases. Sophora flavescens is a traditional herbal medicine used to reduce inflammation, but no study has examined its ability to block IL-beta production. Here, we show that S. flavescens reduced the Pseudomonas aeruginosa-induced expression of IL-1 beta by lung epithelial cells and macrophages. S. flavescens was also effective at reducing IL-1 beta production induced by either Staphylococcus aureus or phorbol 1 2-myristate 13-acetate, indicating that the effect is generalizable to diverse inflammatory stimuli. In addition, S. flavescens blocked the phosphorylafion of IKK alpha/beta, key upstream kinases involved in the degradation of I kappa B alpha, and the cleavage of caspase-1, a key component of the inflammasome. Thus, this study demonstrates that S. flavescens exerts its anti-inflammatory effects by blocking P. aeruginosa-mediated NF-kappa B/inflammasome activation and the subsequent production of IL-1 beta.