Fig 4. Effects of NiCl2 on the LPS-induced phosphorylation of ERK1/2, p38 MAPK, and JNK as well as IL-6 promoter activity.

(A) RAW264 cells were incubated in medium containing LPS (1 μg/ml) in the presence or absence of NiCl₂ (300 μM) for 15 min. The protein levels of p-ERK, ERK, p-p38, p38, p-JNK, JNK, and actin were determined in cell lysates by immunoblotting. Data are representative of three independent experiments. (B) RAW264 cells were transiently transfected with a luciferase gene construct with the IL-6 promoter and, 24 h later, were then stimulated for 8 h with LPS (1 μg/ml) in the presence or absence of NiCl₂ (300 μM). Luciferase activity was determined in these cells. Values are normalized to those of Renilla luciferase activity and the mean value of the control was set to 1.0. Data represent the mean ± S.E.M. (n = 3). **p < 0.01 between the indicated groups. Data are representative of two independent experiments.