Phosphorylation of ERK1/2 and p38 and their potential involvement in SAA-induced IL-8 secretion.
(A) Neutrophils (4 × 105 cells) were stimulated with 2 μM SAA for indicated times. Phosphorylation of ERK1/2 and p38 was determined by Western blotting, using specific antibodies against phospho-ERK1/2 and phospho-p38. The unphosphorylated ERK1/2 and p38 were also determined. Three experiments were performed and a representative set of data is shown. (B) Neutrophils were treated with the MEK inhibitor U0126 or the p38 inhibitor SB202190 for 1 hour prior to SAA (2 μM) stimulation. The secreted IL-8 was measured after 4 hours and expressed as percentage changes. Maximal secretion of IL-8 (1090 pg/mL/106 cells) was obtained in the absence of inhibitor and was set as 100%. Data are presented as means ± SEM of 3 independent experiments, each performed in duplicate.
