p38 MAPK inhibition decreases proIL-1β transcription and translation. THP-1 cells were cultured in the presence of LPS (200 ng/mL) for up to 8 hours. p38 MAPK inhibitor was added 1 hour before LPS treatment. Cells were either snap frozen for determination of IL-1β mRNA content (A) or lysed by adding lysis buffer for determination of proIL-1β protein levels (B). Data are mean plus or minus SEM. Data shown are from 1 of 2 experiments performed in duplicate (*P < .05).