Exp Mol Med.  2002 Nov;34(5):347-352.

Osteoprotegerin is present on the membrane of osteoclasts isolated from mouse long bones

• Woo KM
• Choi Y
• Ko SH
• Ko JS
• Oh KO
• Kim KK

Abstract

Osteoprotegerin (OPG), a member of the tumor necrosis factor receptor superfamily, is known to inhibit osteoclastogenesis by acting as a soluble decoy receptor for the receptor activator of NF-kB ligand (RANKL). We report the presence of OPG on the membrane of osteoclasts and the possibility of the direct action of OPG on them. Highly pure osteoclast precursors were isolated from mouse long bones and induced to differentiate into mature osteoclasts by M-CSF and soluble RANKL (sRANKL). The presence of OPG on the membrane of these cells was confirmed by western blotting and immunostaining. Furthermore, sRANKL was found to be bound to the OPG on the osteoclast precursors. These results suggest that OPG might have a new role during the differentiation of osteoclasts beyond its role as a soluble decoy receptor. The mechanism of the existence of OPG on osteoclast precursors remains to be found.

Keyword

Bone and Bones; cell membrane; cytokine receptors; mice; osteoclast; tumor necrosis factor

MeSH Terms

Animals
Bone and Bones/cytology/*metabolism
Carrier Proteins/immunology/metabolism
Cell Differentiation/drug effects/physiology
Cell Membrane/*metabolism
Cells, Cultured
Glycoproteins/drug effects/*metabolism
Macrophage Colony-Stimulating Factor/pharmacology
Membrane Glycoproteins/immunology/metabolism
Mice
Mice, Inbred ICR
Osteoclasts/drug effects/*metabolism
Receptors, Cytoplasmic and Nuclear/drug effects/*metabolism
Stem Cells/drug effects/metabolism