Osteoblasts/stromal cells stimulate osteoclast activation through expression of osteoclast differentiation factor/RANKL but not macrophage colony-stimulating factor: receptor activator of NF-kappa B ligand.
We previously reported that osteoblasts/stromal cells are essentially involved in the activation as well as differentiation of osteoclasts through a mechanism involving cell-to-cell contact between osteoblasts/stromal cells and osteoclast precursors/osteoclasts. Osteoclast differentiation factor (ODF, also called RANKL/OPGL/TRANCE) and macrophage colony-stimulating factor (M-CSF, also called CSF-1) are two essential factors produced by osteoblasts/stromal cells for osteoclastogenesis. In other words, osteoblasts/stromal cells were not necessary to generate osteoclasts from spleen cells in the presence of both ODF/RANKL and M-CSF. In the present study, we examined the precise roles of ODF/RANKL and M-CSF in the activation of osteoclasts induced by calvarial osteoblasts. Osteoclasts were formed in mouse bone marrow cultures on collagen gel-coated dishes in response to a soluble form of ODF/RANKL (sODF/sRANKL) and M-CSF, and recovered by collagenase digestion. When recovered osteoclasts were further cultured on plastic dishes, most of the osteoclasts spontaneously died within 24 h. Osteoclasts cultured for 24 h on dentine slices could not form resorption pits. Addition of sODF/sRANKL to the recovered osteoclasts markedly enhanced their survival and pit-forming activity. M-CSF similarly stimulated the survival of osteoclasts, but did not induce their pit-forming activity. When primary mouse osteoblasts were added to the recovered osteoclasts, resorption pits were formed on dentine slices. Bone-resorbing factors such as 1alpha,25-dihydroxyvitamin D3, parathyroid hormone, or prostaglandin E2 enhanced pit-forming activity of osteoclasts only in the presence of osteoblasts. M-CSF-deficient osteoblasts prepared from op/op mice similarly enhanced pit-forming activity of osteoclasts. The pit-forming activity of osteoclasts induced by sODF/sRANKL or osteoblasts was completely inhibited by simultaneous addition of osteoprotegerin/osteoclastogenesis inhibitory factor, a decoy receptor of ODF/RANKL. Primary osteoblasts constitutively expressed ODF/RANKL mRNA, and its level was upregulated by treatment with 1alpha,25-dihydroxyvitamin D3, parathyroid hormone, and prostaglandin E2. These results, obtained by using an assay system that unequivocally assesses osteoclast activation, suggest that ODF/RANKL but not M-CSF mediates osteoblast-induced pit-forming activity of osteoclasts, and that bone-resorbing factors stimulate osteoclast activation through upregulation of ODF/RANKL by osteoblasts/stromal cells.
Udagawa
N
N
Department of Biochemistry, School of Dentistry, Showa University, Tokyo, Japan.
Takahashi
N
N
Jimi
E
E
Matsuzaki
K
K
Tsurukai
T
T
Itoh
K
K
Nakagawa
N
N
Yasuda
H
H
Goto
M
M
Tsuda
E
E
Higashio
K
K
Gillespie
M T
MT
Martin
T J
TJ
Suda
T
T
D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D001862:Bone Resorption / Q000188:drug therapy; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000502:physiology; D002450:Cell Communication / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D016173:Macrophage Colony-Stimulating Factor / Q000096:biosynthesis* / Q000502:physiology; D008297:Male; D008562:Membrane Glycoproteins / Q000096:biosynthesis* / Q000502:physiology; D051379:Mice; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D010010:Osteoclasts / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D017154:Stromal Cells / Q000166:cytology / Q000378:metabolism / Q000502:physiology
D002352:Carrier Proteins; D008562:Membrane Glycoproteins; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; C505686:TNFRSF11A protein, human; C505688:TNFSF11 protein, human; C505687:Tnfrsf11a protein, mouse; C505689:Tnfsf11 protein, mouse; D016173:Macrophage Colony-Stimulating Factor