The activation of NF-κB induced by interleukin-1 beta enhances IL-8 release from A549 cell

Objective To investigate the effects of IL-1β on IL-8 release from A549 cell and underlying signal transduction pathways.Methods A549 cells were pre-incubated with AS602868 (3 μM, specific IKK2 inhibitor) and/or pre-treated with 1 ng/ml IL-1β. The phosphorylated IκBα and IκBα expressions were determined by Western blot.Laser scanning confocal microscope (LSCM) was used to examine the translocation of p65 and p50 at 30 min after stimulation.DNA binding activity of p65 and p50 in nuclear extracts were detected at 1 hour following IL-1β treatment,and IL-8 protein concentrations in the medium were measured by ELISA at 24 hours after IL-1β was added. Results IL-1β induced rapid phosphorylation of IκBα and its subsequent degradation. LSCM graphs showed that IL-1β stimulated the translocation of p65 and p50 from the cytosol to the nucleus. Pre-treated with IL-1β significantly increased the DNA binding ability of p65 (P0.01) and p50 (P0.01) in cell nuclear extracts. IL-1β significantly augmented IL-8 secretion from A549 cells(P0.01). Pre-incubation with AS602868 inhibited IL-1β-induced enhancement of IκBα kinase activity and degradation of IκBα protein, blocked p65 and p50 nuclear translocation, caused a significant reduction in IL-1β-induced DNA binding activity for both p65 (P0.01) and p50 (P0.01) and suppressed IL-8 production following IL-1β stimulation (P0.01). Conclusion The activation of NF-κB induced by IL-1β may enhance IL-8 release in A549 cells,suggesting that the specific NF-κB inhibitors could be useful in the treatments of biotrauma of VALI.