Figure 4

Involvement of MAPK pathways in LPS-induced iNOS production in BV-2 cells. A-B, BV-2 cells were treated with LPS (1 μg/ml) for 6 hr in the presence of SB205380 (SB), SP600125 (SP) or U0126 (U); inhibitors to block phosphorylation of p38, JNK (A) and ERK1/2 (B), respectively. The three MAPK inhibitors almost completely blocked iNOS induction in LPS-activated microglia. A representative experiment of three that were performed is shown. C. BV-2 cells were treated with MAPK inhibitors followed by LPS induction for 24 hr. Culture media were collected for measurements of nitrite production using a nitrite/nitrate assay kit. ***, p < 0.001 was obtained when the SB-, SP- and U-treated groups were compared to the LPS alone group. A representative experiment of four that were performed is shown. D, BV-2 cells were treated with LPS (1 μg/ml) for 15 min in the presence of PKC inhibitors at the indicated concentrations. Cell extracts from the treated cells were subjected to western blot with antibodies against phosphorylated and total ERK1/2, p38 and JNK. The relative intensities of phosphorylated versus total ERK1/2, p38 and JNK were quantified using densitometric analysis based on 3 different experiments. *, p < 0.05 and **, p < 0.01 were obtained when the drug-treated groups were compared to the LPS alone group.