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

Bone. 1999 Nov;25(5):517-23. doi: 10.1016/s8756-3282(99)00210-0.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bone Marrow Cells / cytology*
  • Bone Marrow Cells / drug effects
  • Bone Marrow Cells / physiology
  • Bone Resorption / drug therapy
  • Carrier Proteins / biosynthesis*
  • Carrier Proteins / physiology
  • Cell Communication / drug effects
  • Cell Differentiation / drug effects
  • Cell Differentiation / physiology
  • Cell Survival / drug effects
  • Cells, Cultured
  • Female
  • Humans
  • Macrophage Colony-Stimulating Factor / biosynthesis*
  • Macrophage Colony-Stimulating Factor / physiology
  • Male
  • Membrane Glycoproteins / biosynthesis*
  • Membrane Glycoproteins / physiology
  • Mice
  • Osteoblasts / cytology
  • Osteoblasts / metabolism
  • Osteoblasts / physiology*
  • Osteoclasts / cytology
  • Osteoclasts / drug effects
  • Osteoclasts / physiology*
  • RANK Ligand
  • Receptor Activator of Nuclear Factor-kappa B
  • Stromal Cells / cytology
  • Stromal Cells / metabolism
  • Stromal Cells / physiology


  • Carrier Proteins
  • Membrane Glycoproteins
  • RANK Ligand
  • Receptor Activator of Nuclear Factor-kappa B
  • TNFRSF11A protein, human
  • TNFSF11 protein, human
  • Tnfrsf11a protein, mouse
  • Tnfsf11 protein, mouse
  • Macrophage Colony-Stimulating Factor