Fatty acid cyclooxygenase activity stimulated by transforming growth factor-beta in mouse osteoblastic cells (MC3T3-E1).
Prostaglandin (PG)E2, a bone-resorption factor, was released essentially as the sole arachidonate metabolite by an osteogenic cell line cloned from mouse calvaria (MC3T3-E1). Transforming growth factor (TGF)-beta (1 ng/ml) or epidermal growth factor (EGF) (10 ng/ml) markedly stimulated the endogenous PGE2 synthesis in the presence of 5% newborn bovine serum. The serum could not be omitted even if both TGF-beta and EGF were added simultaneously. The PGE2 synthesis started after a 1-h lag phase, and reached a maximum at about 3 h after the addition of TGF-beta. The presence of TGF-beta enhanced the cyclooxygenase activity (arachidonic acid----PGH2) assayed with the microsomes or the immunoprecipitate from the solubilized enzyme. The TGF-beta-stimulated PGE2 synthesis was blocked by translation and transcription inhibitors. Furthermore, Western blot analysis using anti-cyclooxygenase antibody demonstrated a higher level of cyclooxygenase in the TGF-beta-treated cells than in the nontreated cells. These experimental results suggested an induction of cyclooxygenase by TGF-beta as previously reported for EGF (K. Yokota et al. (1986) J. Biol. Chem. 261, 15,410-15,415).
Sumitani
K
K
Department of Orthodontics, School of Dentistry, Tokushima University, Japan.
Kawata
T
T
Yoshimoto
T
T
Yamamoto
S
S
Kumegawa
M
M
D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism; D015153:Blotting, Western; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D015232:Dinoprostone / Q000096:biosynthesis; D004790:Enzyme Induction / Q000187:drug effects; D004815:Epidermal Growth Factor / Q000494:pharmacology; D051379:Mice; D010006:Osteoblasts / Q000187:drug effects / Q000201:enzymology*; D011233:Precipitin Tests; D011451:Prostaglandin-Endoperoxide Synthases / Q000032:analysis / Q000378:metabolism*; D013997:Time Factors; D015291:Transforming Growth Factors / Q000037:antagonists & inhibitors / Q000494:pharmacology*
D001095:Arachidonic Acids; D016718:Arachidonic Acid; D004815:Epidermal Growth Factor; D015291:Transforming Growth Factors; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone