Journal of Bone and Mineral Metabolism

, Volume 19, Issue 1, pp 13–19

Effect of extracellular calcium on the gene expression of bone morphogenetic protein-2 and -4 of normal human bone cells

  • Osamu Nakade
  • Kanae Takahashi
  • Taishin Takuma
  • Takashi Aoki
  • Tohru Kaku

DOI: 10.1007/s007740170055

Cite this article as:
Nakade, O., Takahashi, K., Takuma, T. et al. J Bone Miner Metab (2001) 19: 13. doi:10.1007/s007740170055

Abstract

A high extracellular calcium level inhibits the formation of osteoclast-like cells and stimulates osteoblastic proliferation, indicating that extracellular calcium plays an important role in the process of bone remodeling. The present study examined the effects of a high extracellular calcium level on mRNA levels of bone morphogenetic protein (BMP)-2 and -4, which are well-documented osteoinductive proteins, and the differentiation of normal human mandible-derived bone cells in vitro. High extracellular calcium significantly increased cell proliferation at an optimal dose of 0.4 mM CaCl2 added to control medium containing 1.8 mM CaCl2. The addition of 0.1–0.4 mM CaCl2 markedly increased the mRNA levels of BMP-2 and -4 following incubation for 0.5 and 24 h as evaluated by reverse transcription–polymerase chain reaction. While an increased extracellular calcium level (addition of 0.1–1.2 mM CaCl2) failed to increase alkaline phosphatase activity and osteocalcin secretion, it did significantly increase type I collagen synthesis, monitored by the production of procollagen type I carboxy-terminal peptide. These results indicate that the extracellular calcium level regulates BMPs and type I collagen synthesis in osteoblastic cells.

Key words extracellular calciumbone morphogenetic proteins (BMPs)human osteoblastic cellsdifferentiationtype I collagen synthesis

Copyright information

© Springer-Verlag Tokyo 2001

Authors and Affiliations

  • Osamu Nakade
    • 1
  • Kanae Takahashi
    • 1
  • Taishin Takuma
    • 2
  • Takashi Aoki
    • 3
  • Tohru Kaku
    • 1
  1. 1.Departments of Oral Pathology, and
  2. 2.Oral Biochemistry, School of Dentistry, and
  3. 3.Department of Biochemistry, Faculty of Pharmaceutical Science, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, JapanJP