Effect of Dex on MAPK activation during TLR3 and TLR9 coengagement. (A) Peritoneal macrophages were pretreated with Dex followed by Poly (I:C) and CpG cotreatment for the indicated periods of time. Cell lysates were analyzed by Western blot using anti–phospho-JNK (P-p46/p54) and total JNK (total p46/p54); anti–phospho-ERK1/2 (P-ERK1/2) and total ERK1/2; and anti–phospho-p38 MAPK (P-p38MAPK) and total p38 MAPK antibodies. (B) Effect of Dex on LPS-induced JNK activation in Lps2 mutant and Trif^−/− macrophages. Peritoneal macrophages isolated from Lps2 mutant and Trif^−/− mice treated with LPS for the indicated periods of time in the presence and absence of 100nM Dex. (C) Effect of Dex on LPS-induced IκBα degradation in Lps2 mutant and Trif^−/− macrophages. Macrophages were treated with or without Dex for 3 hours followed by LPS for 30 minutes. Cytoplasmic extracts were analyzed by Western blotting using anti-IκBα and anti–β-actin antibodies. Representative of 2 to 3 independent experiments.