| Co-Investigator(Kenkyū-buntansha) |
URUSHIZAKI Toshiko Nihon University, School of Dentistry, Research Associate, 歯学部, 助手 (80297845)
KAMIYA Naoko Nihon University, School of Dentistry, Research Associat, 歯学部, 助手 (80287656)
SHIGEMASA Kayoko Nihon University, School of Dentistry, Research Associate, 歯学部, 助手 (30059604)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1999: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1998: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
The influence of bone morphogenetic protein-2 (BMP-2) and transforming growth factor β (TGF-β) on the expression of small proteoglycans, decorin and biglycan was investigated in a clonal rat osteoblastic cell line, ROS-C26 (C26) cells, which is a potential osteoblast precursor cell line and capable of differentiating into mature osteoblasts after treatment with recombinant BMP-2 (rhBMP-2). Following the culture of C26 cells for 3, 6, and 9 days in the presence or absence of rhBMP-2, alkaline phosphatase activity increased in the rhBMP-2 treated cells in direct proportion to their differentiation into more mature osteoblastic cells, whereas decorin mRNA decreased in the cells, when compared to control cells without rhBMP-2 treatment. These results were evident 6 days after treatment. However, rhBMP-2 treatment had no effect on biglycan mRNA expression in the cells. Subsequently, after removal of rhBMP-2 from the culture media, the cells were further cultured for 24 h with graded concentrations of TGF-β1 (0,0.1,1.0, 5.0, and 10 ng/ml). TGF-β1 decreased decorin mRNA expression in the cells dose dependently, but did not effect their biglycan mRNA expression. Furthermore, either removal of rhBMP-2 from the culture media or addition of TGF-β1 significantly decreased alkaline phosphatase activity of rhBMP-2-induced cells. There results indicate that osteoblastic differentiation is accompanied by increased alkaline phosphatase activity and decreased expression of decorin mRNA, but continuous expression of biglycan mRNA. Both rhBMP-2 and TGF-β1 inhibit decorin mRNA expression in osteoblasts at varying stages of differentiation, but their effects on biglycan mRNA expression and alkaline phosphatase are different.
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