JNK activation is required for LPS-induced Jag1 expression in macrophages. (A) Time course of LPS-induced expression of Jag1 protein. (), fold change as compared to basal level (B) MAPK signal pathways were activated by LPS stimulation in macrophages. (C) Cells were pretreated with 10 μM PD98059 (PD), 2 μM SB203580 (SB), 50 μM SP600125 (SP), or DMSO (D) as control 30 minutes before LPS stimulation, respectively. LPS-induced Jag1 expression was completely blocked by SP600125, a JNK inhibitor. (D) Relative levels of Jag1 protein were determined by densitometry (n = 3). The results represent the mean ± SD of three independent experiments. *, P < 0.05 compared to control; #, P < 0.05 compared to LPS only.