Figure 6. ERK1/2 mediated DEX- and NDV-induced cooperative IL-10 mRNA expression in DCs.

A. ERK inhibitor U0126 abolished DEX- and NDV-induced cooperative IL-10 mRNA expression in DCs. DCs were pre-treated with indicated kinase inhibitors for 30 min (p38 MAPK inhibitors SB203850 (1 µM) and MT4 (10 µM); the ERK inhibitor U0126 (0.1 M); and the PKA inhibitor H-89 (12.5 nM)). They were then treated with DEX (10⁻⁶ M) for 30 min, and were infected with NDV (MOI = 10) for 6 hours. **: p<0.01, compared the 2 conditions indicated. B. ERK inhibitor U0126 dose-dependently reduced DEX-and NDV-induced cooperative IL-10 mRNA and protein expression in DCs. DCs were pre-treated with increasing concentrations of U0126 (0.1 M, 1 M and 10 M), and were treated with DEX (10⁻⁶ M) for 30 min. They were then infected with NDV (MOI = 10) for 6 hours. Bars represent means and standard errors of fold changes of the IL-10 mRNA (left panel) and protein concentrations in culture media (right panel). *: p<0.05, **: p<0.01, ***: p<0.001, compared to the 2 conditions indicated. C. NDV infection but not DEX pre-treatment activated ERK1/2 in DCs. DCs were treated with DEX (10⁻⁶ M), or were infected with NDV (MOI = 10) for 6 hours. Whole cell extracts were obtained after 24 hours of infection, and were run on SDS-PAGE gels. Phosphorylated ERK1/2 and their entire fraction were visualized with their specific antibodies in Western blots.