Nontypeable haemophilus influenzae induces IL-8 expression in alveolar epithelial cells in a p38MAPK and NF-?B dependent manner

AIM: To investigate the key molecular mechanism of inflammatory response in alveolar epithelial cells induced by nontypeable haemophilus influenzae(NTHi).METHODS: A549 cells were co-cultured with NTHi(multiplicity of infection,MOI: 10) and harvested 15 min and 30 min after stimulation.The phosphorylation of p38 mitogen activated protein kinase(p38 MAPK) in A549 cells was detected by Western blotting.The intracellular expression of nuclear factor-?B(NF-?B) p65 was examined by flow cytometry 4 h after stimulation.A549 cells were preincubated with p38 inhibitor(SB203580) or NF-?B inhibitor(PDTC) for 1 h and then stimulated with NTHi for 24 h.The level of interleukin 8(IL-8) in the supernatants was determined by enzyme-linked immunosorbent assay(ELISA).RESULTS: The phosphorylation of p38 MAPK was rapidly induced by NTHi stimulation.The expression of NF-?B p65 in A549 cells after NTHi stimulation was significantly up-regulated compared with control group(P