PM2.5 stimulated the release of cytokines from BEAS-2B cells through activation of IKK/NF-κB pathway

Previous studies indicated that exposure to fine particulate matter (PM2.5) was related to pulmonary inflammatory diseases through activation of nuclear factor kappa B (NF-kappa B) signaling pathway to trigger cytokine secretions in human lung carcinoma cells. To investigate the potential mechanisms underlying expression of cytokines via activated NF-kappa B by PM2.5, human bronchial epithelial cells (BEAS-2B cells) were treated with PM2.5 extracts at different concentrations (6, 13, 25, 50, 100, 200, and 400 mu g mL(-1)) for 6 and 24 h. We found that 100 mu g mL(-1) PM2.5 increased interleukin 6 (IL-6) and IL-8 expression at 24 h (p < 0.05 or p < 0.01). Moreover, 100 mu g mL(-1) PM2.5 upregulated phosphorylated I kappa B kinase (IKK), p65, and I kappa B alpha at 6 h, which could be reversed by the IKK inhibitor Bay11-7082 (p < 0.05 or p < 0.01). The p65 subunit of NF-kappa B was translocated into the nucleus of the cells treated with 100 mu g mL(-1) PM2.5 at 6 and 24 h. Bay11-7082 partly inhibited PM2.5-induced increases of IL-6 and IL-8 secretion. The results indicated that PM2.5 extract increased IL-6 and IL-8 levels in BEAS-2B cells through activation of IKK/NF-kappa B pathway. Our study will contribute to better understanding of the mechanism of PM2.5-induced pulmonary inflammatory diseases.