FIG 4.

Inhibition of p38 MAPK decreases COX-2 protein levels but not cPLA₂ phosphorylation. (A) BMDMs were either untreated or pretreated with 15 μM SB203580 (p38 MAPK inhibitor) for 1 h prior to inoculation with LVS at an MOI of 200:1. At 1 h postinoculation, whole-cell lysates were collected and analyzed for cPLA₂ phosphorylated on Ser⁵⁰⁵ by Western blotting (left). The band intensities (right) were measured in each experiment using LiCor Odyssey infrared imaging system software and were normalized to the loading control (tubulin). The graph presents data from three independent experiments. (B and C) RAW264.7 cells were either untreated or pretreated with 15 μM SB203580 for 1 h prior to inoculation with LVS at an MOI of 200:1. At 2 h postinoculation, the cells were incubated in RPMI containing penicillin-streptomycin. At 4 h (B) and 18 h (C) postinoculation, whole-cell lysates were collected and analyzed for COX-2 protein levels by Western blotting (left). The band intensities (right) were measured in each experiment and were normalized to the loading control tubulin. The graphs present data from three independent experiments. Statistical differences (**, P ≤ 0.01; ***, P ≤ 0.001) compared to infected untreated controls were determined by Dunnett's multiple comparison test.