| Project/Area Number |
15390641
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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 |
Orthodontic/Pediatric dentistry
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| Research Institution | Matsumoto Dental University |
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Principal Investigator |
HOSOYA Akihiro (2004) Matsumoto Dental University, School of Dentistry, Research Assistant, 歯学部, 助手 (70350824)
小林 泰浩 (2003) 松本歯科大学, 大学院・歯学独立研究科, 助教授 (20264252)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAHASHI Naoyuki Matsumoto Dental University, Graduate School of Oral Medicine, Professor, 大学院・歯学独立研究科, 教授 (90119222)
OZAWA Hidehiro Matsumoto Dental University, Graduate School of Oral Medicine, Professor, 大学院・歯学独立研究科, 教授 (60018413)
NAKAMICHI Yuko Matsumoto Dental University, Institute of Oral Science, Research Assistant, 総合歯科医学研究所, 助手 (20350829)
MIZOGUCHI Toshihide Matsumoto Dental University, Institute of Oral Science, Research Assistant, 総合歯科医学研究所, 助手 (90329475)
細矢 明宏 松本歯科大学, 歯学部, 助手 (70350824)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥14,500,000 (Direct Cost: ¥14,500,000)
Fiscal Year 2004: ¥7,800,000 (Direct Cost: ¥7,800,000)
Fiscal Year 2003: ¥6,700,000 (Direct Cost: ¥6,700,000)
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| Keywords | osteocyte / mechanical stress / apotosis / bone remodeling / estrogen receptor / tamoxifen / Fas / osteoblast / 機械的刺激 / プロスタグランジンE_2 / RANKL / PGE_2受容体 / RAW264.7 / NF-κB / p38 MAPK / 破骨細胞 |
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| Research Abstract |
In maxillo-mandibular growth and development, osteocytes absorb mechanical stress generated by muscle contraction and deform bone structure. Thus, osteocytes are thought to be mechanosensory cells that respond to mechanical stress by sending signals to other bone cells to initiate bone remodeling. However, it has been difficult to show that osteocytic lineage are involved in bone remodeling in vivo. In present study, to define the role of osteocytes in the control of bone remodeling, we have tried to generate an inducible osteocyte ablation mouse model. Precisely, transgenic mice have been generated with mouse dentin matrix protein-1 (dmp-l) promoter, which is used to drive expression of Fas fused to mutant estrogen receptor (Fas-ER^t). Dmp-1 is an osteocyte-specific gene, and is expressed only in differentiated osteocytes but not in osteoblasts. Cells expressing (Fas-ER^t) die of tamoxifen treatment, expression of Fas-ER^t in osteocytes should allow inducible ablation of differentiated osteocytes in vivo without affecting the precursor cells, osteoblasts. First, we generated fusion genes composed of various length of the mouse dmp-1promoter fused to GFP reporter gene. The dmp-1-GFP fusion genes were transfected into osteoblastic MC3T3-E1 cells and some stable transformants were obtained. The transformants were cultured for 30 days and GFP activity was measured every days. Osteocyte-specific enhancer activity was observed in region between -1200 and -800bp. Next, we constructed Flag-tagged Fas-ER^t fusion gene and transiently transfected the gene into MC3T3-E1 cells. We tried to induce apoptosis in Flag-Fas-ER^t expressing cells by addition of anti-Flag antibody and tamoxifen, but we were able to induce cell death in only 30% population of these cells. We have examined another system that is more effective than Fas-ER^t. We have considered to use diphtheria-toxin receptor or herpes simplex virus thymidine kinase for inducible cell ablation system.
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