IL-8 promotes pyroptosis through ERK pathway and mediates glucocorticoid resistance in chronic rhinosinusitis with nasal polyps

This study seeks to elucidate the role and molecular mechanisms of IL-8 in nasal epithelial cell pyroptosis and its impact on glucocorticoid (GC) resistance. We assessed the expression of pyroptosis-related biomarkers and IL-8 in tissues and human nasal epithelial cells (hNECs) from both control and nasal polyp patients using western blot. Their localization was determined through immunohistochemistry and immunofluorescence. Cell death and cytotoxicity assay, electron microscopy, ELISA, and immunofluorescence were utilized to investigate IL-8-induced pyroptosis and GC resistance in hNECs, alongside the examination of the involved signaling pathways via western blot and immunofluorescence. In a murine model, hematoxylin-eosin staining and immunohistochemistry clarified relationship between pyroptosis and GC resistance. IL-8 and pyroptotic biomarker expression were significantly higher in nasal polyp-derived tissues and hNECs compared to controls. IL-8 showed a positive correlation and co-localized with the pyroptotic biomarkers. IL-8 triggered pyroptosis in hNECs by activating the ERK signaling pathway, leading to increased IL-1β and IL-18 secretion. Moreover, IL-8-induced pyroptosis was found to contribute to GC resistance by affecting phosphorylation of GC receptor Ser211. Inhibition of pyroptotic proteins mitigated IL-8-induced GC resistance both in vitro and in vivo. Elevated IL-8 facilitates pyroptosis via the ERK signaling pathway and plays a significant role in GC resistance in nasal polyps.