Murine osteoclast formation and function: differential regulation by humoral agents.
Although much has been learned recently of the mechanisms that regulate osteoclastic differentiation, much less is known of the means through which their resorptive activity is controlled. We have developed an assay that allows us to measure resorptive activity while minimizing the confounding effects of the test agent on differentiation. In this assay, murine osteoclasts were harvested from plastic substrates and sedimented onto bone slices in MEM with 10% fetal calf serum. The majority excavate the bone surface within a few hours. We found that the regulation of resorption was distinct from that of osteoclastogenesis. Thus, interferons-beta and -gamma, which strongly suppress, and TGFbeta, which potently stimulates osteoclast differentiation, were without effect on resorption, whereas IL-1alpha, which does not induce osteoclastogenesis, was a strikingly potent stimulus for bone resorption. TNFalpha and IL-1alpha were able to replace receptor activator of nuclear factor-kappaB ligand for stimulation of bone resorption. Protons stimulated bone resorption only in the presence of a resorptive stimulus. PTH, IL-6, and antibodies against osteoclast-associated receptor did not affect bone resorption. Resorption was potently suppressed by 20 mM calcium, 10 microM cyclosporin A, 1 ng/ml calcitonin, and 1 mM dibutyryl cAMP and cGMP. These results show that full functional differentiation of osteoclasts does not require a signal from bone matrix but can occur on plastic and that osteoclastic differentiation and function are regulated by distinct agents.
Fuller
Karen
K
Department of Cellular and Molecular Medicine, St. George's, University of London, UK.
Kirstein
Barrie
B
Chambers
Timothy J
TJ
D000818:Animals; D001862:Bone Resorption / Q000209:etiology; D002352:Carrier Proteins / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D007375:Interleukin-1 / Q000494:pharmacology; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000494:pharmacology; D051379:Mice; D050778:NFATC Transcription Factors / Q000502:physiology; D010010:Osteoclasts / Q000187:drug effects / Q000502:physiology*; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D002352:Carrier Proteins; D007375:Interleukin-1; D008562:Membrane Glycoproteins; D050778:NFATC Transcription Factors; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; C505687:Tnfrsf11a protein, mouse; C505689:Tnfsf11 protein, mouse; D016212:Transforming Growth Factor beta; D014409:Tumor Necrosis Factor-alpha; D016173:Macrophage Colony-Stimulating Factor