Fibroblast growth factor-2 regulates expression of osteopontin in periodontal ligament cells.
Osteopontin is a protein found in the bone-related matrix and plays multiple regulatory roles in mineralizing and non-mineralizing tissue. In osteogenic cell-lines, the expression of osteopontin increases with the progression of differentiation, but both the expression and function of osteopontin vary with the cell type and its activation state. In this study, we examined the expression of osteopontin by clones established from mouse periodontal ligament, in response to inorganic phosphate and fibroblast growth factor (FGF)-2, which can induce periodontal tissue regeneration. The involvement of inorganic phosphate in the expression of osteopontin during the course of cell differentiation of a clone MPDL22 was confirmed by addition of foscarnet, an inorganic phosphate transport inhibitor. Although FGF-2 decreased the mRNA expression of almost every bone-related protein in MPDL22, FGF-2 upregulated the expression of osteopontin in MPDL22 at both mRNA and protein levels. Interestingly, FGF-2 enhanced the concentration of osteopontin in the culture supernatant of MPDL22, whereas inorganic phosphate did not. The FGF-2-induced osteopontin in the culture supernatant seems to be involved in cell survival activity. An immunohistochemical study showed that the FGF-2-induced osteopontin was mainly present in perinuclear matrices while the inorganic phosphate-induced osteopontin was associated with extracellular matrices in addition to perinuclear matrices. The present results indicated that FGF-2 induces unique expression of osteopontin, which may play a role different from the other bone-related proteins during the process of periodontal tissue regeneration by FGF-2.
Terashima
Yoshimitsu
Y
Department of Periodontology, Division of Oral Biology and Disease Control, Osaka University Graduate School of Dentistry, Osaka, Japan.
Shimabukuro
Yoshio
Y
Terashima
Hiroaki
H
Ozasa
Masao
M
Terakura
Mami
M
Ikezawa
Kazuhiko
K
Hashikawa
Tomoko
T
Takedachi
Masahide
M
Oohara
Hiroyuki
H
Yamada
Satoru
S
Murakami
Shinya
S
D000818:Animals; D017209:Apoptosis; D002454:Cell Differentiation / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism; D002470:Cell Survival; D002478:Cells, Cultured; D005109:Extracellular Matrix / Q000737:chemistry / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D051379:Mice; D053495:Osteopontin / Q000235:genetics / Q000378:metabolism*; D010513:Periodontal Ligament / Q000166:cytology* / Q000378:metabolism; D010710:Phosphates / Q000737:chemistry / Q000378:metabolism
D010710:Phosphates; D016222:Fibroblast Growth Factor 2; D053495:Osteopontin