Fig. 2

Involvement of mitogen-activated protein kinase signaling pathways in H₂O₂-potentiated IL-33 expression. a-d Effect of H₂O₂ on the phosphorylation of MAPK (p38, JNK, ERK1/2) in NCI-H292 cells. Cells were treated with NAC or vehicle prior to treatment with H₂O₂. After 15 min, whole cell lysates were obtained. a Phosphorylation of p38, JNK or ERK was evaluated with immunoblotting. b-d Band intensities were assessed by densitometry. Relative intensity was calculated by dividing the phosphorylated p38, JNK or ERK1/2 band intensity by the p38, JNK or ERK1/2 band intensity and the results were indicated as fold change over control. e-g Effect of p38-MAPK inhibitor (SB203580) (e), JNK inhibitor (SP600125) (f) or ERK inhibitor (U0126) (g) on H₂O₂-potentiated IL-33 expression in NCI-H292 cells. Values are the mean ± SEM (n = 3). **p < 0.01, ***p < 0.001 compared with the values of vehicle-treated cells