Basic fibroblast growth factor upregulates cyclooxygenase-2 in I407 cells through p38 MAP kinase.
The intestinal cell line I407 responds to basic fibroblast growth factor (bFGF) by upregulating cyclooxygenase-2 (COX-2) mRNA and protein expression and increasing PGE(2) production. bFGF treatment of I407 cells results in phosphorylation of p38, and the p38 inhibitor SB-203580 abrogates bFGF-induced PGE(2) synthesis. Wild-type p38alpha (p38alphaWT) and dominant-negative p38alpha (p38alphaDN) stable transfectant clones of I407 cells were used to examine the role of the p38 MAP kinase pathway in the events controlling PGE(2) synthesis after treatment with bFGF. Treatment of p38alphaWT clones with bFGF resulted in increased COX-2 protein levels and PGE(2) synthesis similar to those seen in bFGF-treated control-transfected cells. In contrast, the p38alphaDN clones failed to upregulate COX-2 protein or increase PGE(2) synthesis when treated with bFGF. Exogenous arachidonate did not restore PGE(2) synthesis by p38alphaDN cells. bFGF treatment increased COX-2 mRNA stability, and the p38 inhibitor SB-203580 attenuated COX-2 mRNA stability in bFGF-treated I407 cells. These data demonstrate a crucial role for p38alpha in growth factor-induced PGE(2) synthesis by intestinal cells. Furthermore, they indicate that p38 activity is required at a step distal to arachidonate release, most likely COX-2 upregulation, because exogenous arachidonate did not restore PGE(2) synthesis.
Tessner
Teresa G
TG
Division of Gastroenterology, Washington University, St. Louis, Missouri 63110, USA. stensnlb@im.wustl.edu
Muhale
Filipe
F
Schloemann
Suzanne
S
Cohn
Steven M
SM
Morrison
Aubrey
A
Stenson
William F
WF
D016718:Arachidonic Acid / Q000494:pharmacology; D015153:Blotting, Western; D002460:Cell Line; D051546:Cyclooxygenase 2; D015232:Dinoprostone / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D007527:Isoenzymes / Q000096:biosynthesis*; D008565:Membrane Proteins; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology*; D010766:Phosphorylation; D011401:Promoter Regions, Genetic / Q000235:genetics; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D017468:Receptors, Fibroblast Growth Factor / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D015854:Up-Regulation / Q000187:drug effects; D048051:p38 Mitogen-Activated Protein Kinases
D007527:Isoenzymes; D008565:Membrane Proteins; D012333:RNA, Messenger; D017468:Receptors, Fibroblast Growth Factor; D016222:Fibroblast Growth Factor 2; D016718:Arachidonic Acid; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D015232:Dinoprostone