A p38 MAP kinase inhibitor regulates stability of interleukin‐1‐induced cyclooxygenase‐2 mRNA

Abstract
The mechanism by which p38 mitogen‐activated protein kinase (MAPK) regulates the induction of cyclooxygenase (COX)‐2 by interleukin‐1 (IL‐1) has been investigated in HeLa cells. SB 203580, an inhibitor of p38 MAPK, in the range 0.1–1 μM inhibited IL‐1‐stimulated PGE2 (but not arachidonic acid) release and this was associated with inhibition of induction of COX‐2 protein and mRNA. IL‐1 stimulated COX‐2 transcription in HeLa cells about 2‐fold as judged by both reporter gene and nuclear run‐on assays. The inhibitor had no significant effect on this. However, in cells previously stimulated with IL‐1 it caused rapid destabilisation of COX‐2 mRNA independently of on‐going transcription. The results suggest a novel function for p38 MAPK in the regulation of mRNA stability.