Role of NLRP3 Inflammasome in Eosinophilic and Non-eosinophilic Chronic Rhinosinusitis with Nasal Polyps

The pathophysiologic mechanisms of human chronic rhinosinusitis with nasal polyps (CRSwNP) remain unclear. We aimed to elucidate expression and biologic role of NLRP3 inflammasome in CRSwNP. Immunohistochemistry (IHC) was conducted to assess NLRP3 immunolabeling, real-time polymerase chain reaction (PCR) was used for IL-9 and NLRP3, and caspase-1 level quantitation in CRSwNP and control subjects. In addition, enzyme-linked immunosorbent assay (ELISA) was employed for analyzing concentrations of IL-1 beta and IL-18 in the homogenates prepared from tissue specimens. Moreover, human nasal epithelial cells (HNECs) were used to evaluate the effects of lipopolysaccharide (LPS) and glyburide on NLRP3 inflammasome signaling pathway. Results showed that NLRP3 and caspase-1 were overexpressed in CRSwNP, especially in eosinophilic CRSwNP (ECRSwNP). Interestingly, NLRP3 expression had close correlation to that of caspase-1. Concentrations of IL-1 beta and IL-18 were elevated. NLRP3 inflammasome signaling pathway was augmented by LPS but suppressed by glyburide. In conclusion, NLRP3 inflammasome signaling pathway played a pro-inflammatory role in the pathogenesis of CRSwNP, especially in ECRSwNP. NLRP3 inflammasome signaling pathway was augmented by LPS, but suppressed by glyburide.