Fig. 4.

ERK, p38, and JNK mediate COX-2 induction in response to LPS + IFN-γ. A: rat aortic SMCs were exposed to LPS + IFN-γ for 0–240 min, lysed, and probed for the basal and phosphorylated isoforms of ERK, p38, and JNK by Western blot analysis. Mitogen-activated protein kinase (MAPK) phosphorylation was quantified by densitometric analysis and expressed as phosphorylated-to-total MAPK ratio. Data are means ± SE. *P ≤ 0.05 vs. time zero. B: SMCs were pretreated with inhibitors of ERK (U-0126), p38 (SB-202190), JNK (SP-600125), or in combination for 30 min before stimulation with LPS + IFN-γ (2 h) and were lysed, and COX-2 expression was determined by Western blot analysis. Shown are representative blots. Data are means ± SE. *P ≤ 0.05 vs. control.