FIGURE 6.

sFKN exerts neuroprotective effects via ERK and JNK MAPK signaling. A, protein extracts from BV-2 cells were analyzed by immunoblotting with antibodies specific for phosphorylated and total MAPKs (ERK1/2, JNK, and p38). Cells were treated with 100 nm sFKN for the indicated time periods or 1 μg/ml of LPS for 60 min. *, p < 0.05; **, p < 0.01 compared with untreated control (NT) samples. B, neuron-microglia co-cultures were pretreated with (a–d) or without (e and f) 100 nm sFKN for 3 h in the presence of MAPK inhibitors (MEK1/2 (b and e), 1 μm U0126; JNK (c and f), 10 μm JNK peptide inhibitor L-JNKI; p38 (d), 10 μm SB203580). The cultures were then treated with 10 μm glutamate for 24 h. Staining for neurons (MAP2; green) and microglia (CD11b; red) was then performed. Scale bar, 50 μm. C, neuronal survival rate against glutamate excitotoxicity in the presence of 100 nm sFKN and each MAPK inhibitor (MEK1/2, 1 μm U0126; MEK1, 10 μm PD98059 (PD); JNK, 10 μm L-JNKI and 10 μm SP600125 (SP); p38, 10 μm SB203580 (SB)). The columns indicate the mean ± S.E. from three independent experiments, each of which included analysis of 10 randomly selected fields. ***, p < 0.001 compared with the cultures without MAPK inhibitors.