title: Evidence for the involvement of bone morphogenetic protein-2 in phenytoin-stimulated osteocalcin secretion in human bone cells.
abstract: Recent work has shown that the actions of phenytoin on bone cell proliferation and differentiation are, in part, mediated through the upregulation of transforming growth factor-beta1 (TGF-beta(1)). The present study was undertaken to examine the effect of phenytoin on bone morphogenetic proteins (BMP)-2 and -4, which are well-recognized osteoinductive proteins of the TGF-beta superfamily, in osteoblastic cells. Treatment with 5-50 microM of phenytoin increased the amount of mRNA for BMP-2 after a 0.5-24 h incubation in normal human mandible-derived bone cells (HOB-M cells), but failed to affect the mRNA for BMP-4. Phenytoin treatment for 48 h significantly increased the secretion of BMP-2 by approx. four-fold, at an optimal concentration of 10 microM. While TGF-beta(1) inhibited osteocalcin secretion from HOB-M cells, both phenytoin and BMP-2 significantly stimulated it. Importantly, the stimulatory effects of phenytoin on osteocalcin release were completely blocked by the neutralizing antihuman BMP-2 monoclonal antibody. These results indicate that the stimulatory action of phenytoin on osteocalcin secretion in normal human bone cells is mediated, at least partly, through the upregulation of BMP-2, rather than that of TGF-beta(1).
authors.affiliation: Department of Oral Pathology, School of Dentistry, Health Sciences University of Hokkaido, 061-0293, Ishikari-Tobetsu, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Koyama
authors.forename: O
authors.initials: O
authors.lastname: Nakade
authors.forename: T
authors.initials: T
authors.lastname: Saitoh
authors.forename: T
authors.initials: T
authors.lastname: Takuma
authors.forename: T
authors.initials: T
authors.lastname: Kaku
mesh_terms: D000704:Analysis of Variance; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D000927:Anticonvulsants / Q000494:pharmacology*; D015153:Blotting, Western; D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000187:drug effects* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D006801:Humans; D015151:Immunoblotting; D008334:Mandible / Q000166:cytology; D010006:Osteoblasts / Q000187:drug effects* / Q000378:metabolism; D015675:Osteocalcin / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000378:metabolism*; D010672:Phenytoin / Q000494:pharmacology*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000187:drug effects; D016212:Transforming Growth Factor beta / Q000187:drug effects* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D000911:Antibodies, Monoclonal; D000927:Anticonvulsants; C525718:BMP2 protein, human; C525809:BMP4 protein, human; D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D015675:Osteocalcin; D010672:Phenytoin