title: Osteoblastic differentiation of stromal ST-2 cells from octacalcium phosphate exposure via p38 signaling pathway.
abstract: The present study investigated the role of mitogen-activated protein kinase (MAPK) signaling in osteoblastic differentiation of stromal ST-2 cells induced by synthetic octacalcium phosphate (OCP) incubation. Since our previous studies revealed that OCP consumes calcium ions in media during conversion to hydroxyapatite, the effect of the ions on ST-2 cell differentiation with or without OCP crystals was analyzed. The effect of presence or absence of MAPK inhibitors was also analyzed. OCP increased alkaline phosphatase (ALP) activity and the mRNA expression of differentiation markers via the p38 signaling pathway. The PD98059 MAPK inhibitor increased ALP activity and differentiation marker genes in cells cultured in OCP-coated wells. Reduction of calcium ions in the medium by EGTA increased the ALP activity without OCP in the presence of phosphate ion concentrations up to 7.5 mM. OCP may enhance osteoblastic differentiation through the p38 signaling pathway via the reduction of calcium ions induced by its physicochemical property.
authors.affiliation: Division of Craniofacial function Engineering, Tohoku University Graduate School of Dentistry.
authors.forename: Ryuhei
authors.initials: R
authors.lastname: Nishikawa
authors.forename: Takahisa
authors.initials: T
authors.lastname: Anada
authors.forename: Risa
authors.initials: R
authors.lastname: Ishiko-Uzuka
authors.forename: Osamu
authors.initials: O
authors.lastname: Suzuki
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D002130:Calcium Phosphates / Q000737:chemistry / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects*; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D005419:Flavonoids / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D051379:Mice; D015394:Molecular Structure; D010006:Osteoblasts / Q000166:cytology*; D011725:Pyridines / Q000494:pharmacology; D015398:Signal Transduction; D017154:Stromal Cells / Q000166:cytology* / Q000201:enzymology; D000077191:Wortmannin; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D000730:Androstadienes; D002130:Calcium Phosphates; D005419:Flavonoids; D007093:Imidazoles; D011725:Pyridines; C022045:octacalcium phosphate; D048051:p38 Mitogen-Activated Protein Kinases; D000469:Alkaline Phosphatase; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D000077191:Wortmannin