title: Osteoprotegerin is present on the membrane of osteoclasts isolated from mouse long bones.
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-kappaB 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.
authors.affiliation: College of Dentistry, Kangnung National University, Kangnung 210-702, Korea.
authors.forename: Kyung Mi
authors.initials: KM
authors.lastname: Woo
authors.forename: Youngnim
authors.initials: Y
authors.lastname: Choi
authors.forename: Seong-Hee
authors.initials: SH
authors.lastname: Ko
authors.forename: Jea Seung
authors.initials: JS
authors.lastname: Ko
authors.forename: Kwi-Ok
authors.initials: KO
authors.lastname: Oh
authors.forename: Kack-Kyun
authors.initials: KK
authors.lastname: Kim
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000166:cytology / Q000378:metabolism*; D002352:Carrier Proteins / Q000276:immunology / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D006023:Glycoproteins / Q000187:drug effects / Q000378:metabolism*; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008813:Mice, Inbred ICR; D010010:Osteoclasts / Q000187:drug effects / Q000378:metabolism*; D053244:Osteoprotegerin; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D018160:Receptors, Cytoplasmic and Nuclear / Q000187:drug effects / Q000378:metabolism*; D018124:Receptors, Tumor Necrosis Factor; D013234:Stem Cells / Q000187:drug effects / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D053244:Osteoprotegerin; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D018160:Receptors, Cytoplasmic and Nuclear; D018124:Receptors, Tumor Necrosis Factor; C505687:Tnfrsf11a protein, mouse; C506031:Tnfrsf11b protein, mouse; C505689:Tnfsf11 protein, mouse; D016173:Macrophage Colony-Stimulating Factor