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Functions of osteocytes in bone metabolism

Research Project

Project/Area Number 07457431
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Morphological basic dentistry
Research InstitutionMeikai University

Principal Investigator

KUMEGAWA Masayoshi  Meikai University School of Dentistry, Professor, 歯学部, 教授 (40049367)

Co-Investigator(Kenkyū-buntansha) MANO Hiroshi  School of Dentistry, Meikai University, Assistant, 歯学部, 助手 (20265359)
HAKEDA Yoshiyuki  School of Dentistry, Meikai University, Assistant Professor, 歯学部, 助教授 (90164772)
Project Period (FY) 1995 – 1996
Project Status Completed (Fiscal Year 1996)
Budget Amount *help
¥7,100,000 (Direct Cost: ¥7,100,000)
Fiscal Year 1996: ¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 1995: ¥4,500,000 (Direct Cost: ¥4,500,000)
KeywordsOsteocytes / Inhibition of bone resorption / Rho-GDI like protein / Ca receptor / Vitamin D_3 / Pho-GDIタンパク質 / 破骨細胞抑制因子
Research Abstract

I.In order to investigate roles of osteocytes in bone resorption, the homogenate and conditioned medium of purified chick calvarial osteocytes were examined in a pit formation assay using unfractionated bone cells from mice. The osteocyte homogenate markedly inhibited the pit formation, whereas the conditioned medium of the cells had no effect on the pit formatin. The inhibitory activity was not a result of cytotoxicity of the homogenate. In this study, a bone-resorption inhibitory protein was purified from collagenase-digested chick calvarial fragments enriched in osteocytes. The inhibitory protein, 18.5kDa, showed a significant dose-dependent inhibition of the pit formation by unfractionated bone cells from mice and rabbits, and by human giant cell tumor cells. This protein also inhibited the bone-resorbing activity of purified osteoclasts in the pit formation assay in the absence of other effector cells. Microinjection of the protein into osteoclasts caused disruption of the podosomes in the cells. The N-terminal 25-amino acid sequence of the protein was 68% homologous to a part of Rho-GDI.Osteocytes may be involved in the regulatory mechanism of bone resorption by osteoclasts.
II.Vitamin D_3 regulates the amount of calcium receptor (CaSR) mRNA Vitamin D_3 decreases the amount of CaSR mRNA in occipital bone, but the hormone increases that of CaSR mRNA in long bone and kidney. These results indicate the presence of tissue specific regulation in CaSR by Vitamin D_3.

Report

(3 results)
  • 1996 Annual Research Report   Final Research Report Summary
  • 1995 Annual Research Report
  • Research Products

    (8 results)

All Other

All Publications (8 results)

  • [Publications] 松尾哲: "骨細胞の分離法の確立と増殖の可能性について." 明海大学歯学雑誌. 25. 167-175 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] Tanaka,K.,Yamaguchi,Y.and Hakeda.Y.:"Isolated chick osteocytes stimulate formation and bone-resorbing activity of osteoclast-like cells." J.Bone Miner.Metab.13. 61-70 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] Tetsu Matsuo: "Isolation of Osteocytes and Probability of Cell Proliferation" J.Meikai.Univ.Sch.Dent.25. 167-175 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] Tanaka, K., Yamaguchi, Y.and Hakeda, Y.: "Isolated chick osteocytes stimulate formation and bone-resorbing activity of osteoclast-like cells." J.Bone Miner.Metab.13. 61-70 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] 松尾哲: "骨細胞の分離法の確率と増殖の可能性について" 明海大学歯学雑誌. 25. 167-175 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] Tanaka,K.,Yamaguchi,Y.and Hakeda,Y.: "Isolated chick osteocytes stimulate formation and bone-resorbing activity of osteoelast like cells." J.Bone Miner.Metab.,. 13. 61-70 (1995)

    • Related Report
      1996 Annual Research Report
  • [Publications] Y. Honda, M. Kumegawa et al.: "Calcium-sensing receptor in osteocytes" J. Bone Miner. Res.10. S154- (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] A. Maejima, M. Kumegawa et al.: "Osteocytes produce osteoclastic bone-resorption inhibitory factor" J. Bone Miner. Res.10. S222- (1995)

    • Related Report
      1995 Annual Research Report

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Published: 1995-04-01   Modified: 2016-04-21  

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