| Project/Area Number |
14370598
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Functional basic dentistry
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| Research Institution | Kanagawa Dental College |
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Principal Investigator |
HATA Ryu-ichiro Kanagawa Dental College, Dentistry, Professor, 歯学部, 教授 (10014276)
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| Co-Investigator(Kenkyū-buntansha) |
KATO Yasumasa Kanagawa Dental College, Dentistry, Lecturer, 歯学部, 講師 (50214408)
IZUKURI Kazuhito Kanagawa Dental College, Dentistry, Assistant, 歯学部, 助手 (90257296)
古江 美保 神奈川歯科大学, 歯学部, 講師 (80257310)
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| Project Period (FY) |
2002 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥13,100,000 (Direct Cost: ¥13,100,000)
Fiscal Year 2005: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2004: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2003: ¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 2002: ¥7,400,000 (Direct Cost: ¥7,400,000)
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| Keywords | collagen / differentiation of osteoblasts / a long-acting vitamin C / 1α, 25 (OH)_2 vitamin D_3 / human osteoblasts / MG63 / 活性持続性ビタミンC |
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| Research Abstract |
In order to investigate the mechanisms by which 1α25 (OH)_2 vitamin D_3 (VD_3) stimulates the differentiation of human osteoblasts, we cultured MG-63, which is a human osteoblastic cell line, in the presence or absence of VD_3 and/or L-ascorbic acid 2-phosphate (Asc 2-P), a long-acting vitamin C derivative. The cell growth rate was decreased by the presence of VD_3 in the culture medium. Type I collagen synthesis and alkaline phosphatase (ALP) activity, which are markers of early stage osteoblast differentiation, were stimulated by the presence of VD_3 as well as by that of Asc 2-P. The co-presence of Asc 2-P and VD_3 had a synergistic effect on the collagen synthesis and ALP activity of the cells. Inhibition of collagen synthesis by the addition of inhibitors of collagen synthesis to the medium attenuated the stimulative effect of VD_3 and Asc 2-P on the ALP activity. Transfection of the cells with siRNA-expressing vectors for COL1A1 decreased the expression level of ALP mRNA in addit
… More
ion to that of COL1A1. On the other hand, ALP activity was significantly increased, and the growth rate was decreased, when the cells were cultured on type I collagen-coated dishes. These effects were not seen when the cells were cultured on dishes coated with heat-denatured collagen. VD_3 also increased the mRNA levels for Runx2 and osterix, which are transcription factors critical for osteoblast differentiation, as well as those of differentiation markers such as bone/liver/kidney type ALP,COL1A1, (the gene for the α1 chain of type I collagen), and osteocalcin, in the cells. Normal human osteoblasts and human bone marrow-derived mesenchymal stem cells (hBMSC) showed quite similar responses to VD_3. These results indicate that VD_3 -stimulated gene expression of type I collagen and that mature type I collagen produced in the presence of Asc 2-P mediates at least a part of the stimulative effects of Asc 2-P and VD_3 on the differentiation of these human osteoblastic cells. Levels of mRNAs for ALP and COL1A1were increased, but the level of Runx2 was decreased, by the expression of osterix in MG-63 cells. These results also suggest that VD_3 controls the growth and differentiation of human osteoblastic cells by regulating the gene expression of osteoblast-related transcription factors as well as that of type I collagen, and that the co-presence of both signals is essential for VD_3 to express full activity toward the differentiation of human osteoblasts. Less
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