Role of p38 MAPK activity in control of KC mRNA stability. (A) RAW264.7 cells were stimulated with nothing (NT) or LPS (10 ng/mL) for 2 hours prior to the addition of ActD in the presence or absence of SB203580 (2 μM) or PD980589 (50 μM) as indicated. Total RNA was prepared at 0, 1, and 2 hours after ActD treatment and analyzed by Northern hybridization for KC mRNA levels. Similar results were obtained in 2 separate experiments. (B). RAW264.7 cells were treated or not with TGFβ for 3 hours and subsequently stimulated with LPS (10 ng/mL) for the indicated times. Total cell lysates were prepared and analyzed for both phosphorylated p38 and total p38 levels by Western blot. The film was quantified using the NIH IMAGE software package. Similar results were obtained in separate experiments.