TY - JOUR
T1 - Chick osteocyte-derived protein inhibits osteoclastic bone resorption
AU - Maejima-Ikeda, Akiko
AU - Aoki, Mari
AU - Tsuritani, Katsuki
AU - Kamioka, Kayo
AU - Hiura, Kenji
AU - Miyoshi, Toshio
AU - Hara, Hiroshi
AU - Takano-Yamamoto, Teruko
AU - Kumegawa, Masayoshi
N1 - Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 1997/2/15
Y1 - 1997/2/15
N2 - In order to investigate the role of osteocytes in bone resorption, we examined the homogenate and conditioned medium from purified chick calvarial osteocytes in a pit-formation assay using unfractionated bone cells from mice. The osteocyte homogenate markedly inhibited pit formation, whereas the conditioned medium of osteocytes had no effect. This inhibitory activity was not the result of cytotoxicity of the homogenate. A novel bone-resorption-inhibitory protein was purified from collagenase-digested chick calvarial fragments enriched in osteocytes. The inhibitory protein, of molecular mass 18.5 kDa, showed significant dose-dependent inhibition of pit formation by unfractionated bone cells from mice and rabbits, and by human giant tumour 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 showed 68% identity to a part of Rho-GTP-dissociation inhibitor. Thus chick calvarial osteocytes may be involved in the regulation of bone resorption by osteoclasts.
AB - In order to investigate the role of osteocytes in bone resorption, we examined the homogenate and conditioned medium from purified chick calvarial osteocytes in a pit-formation assay using unfractionated bone cells from mice. The osteocyte homogenate markedly inhibited pit formation, whereas the conditioned medium of osteocytes had no effect. This inhibitory activity was not the result of cytotoxicity of the homogenate. A novel bone-resorption-inhibitory protein was purified from collagenase-digested chick calvarial fragments enriched in osteocytes. The inhibitory protein, of molecular mass 18.5 kDa, showed significant dose-dependent inhibition of pit formation by unfractionated bone cells from mice and rabbits, and by human giant tumour 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 showed 68% identity to a part of Rho-GTP-dissociation inhibitor. Thus chick calvarial osteocytes may be involved in the regulation of bone resorption by osteoclasts.
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U2 - 10.1042/bj3220245
DO - 10.1042/bj3220245
M3 - Article
C2 - 9078269
AN - SCOPUS:0031057637
VL - 322
SP - 245
EP - 250
JO - Biochemical Journal
JF - Biochemical Journal
SN - 0264-6021
IS - 1
ER -