title: Inhibition of osteoclast formation by 3-methylcholanthrene, a ligand for arylhydrocarbon receptor: suppression of osteoclast differentiation factor in osteogenic cells.
abstract: We investigated the effects of 3-methylcholanthrene (3MC), a ligand for arylhydrocarbon receptor (AhR), on osteoclastogenesis. Osteoclast-like cells, in cocultures with mouse spleen cells and clonal osteogenic stromal ST2 cells, are formed from spleen cells by a combination of the receptor activator of nuclear factor-kappaB ligand (RANKL) and macrophage colony-stimulating factor (M-CSF) produced by ST2 cells in response to 1alpha,25(OH)(2) Vitamin D(3). 3MC dose-dependently inhibited the formation of mono- and multinuclear osteoclast-like cells. However, 3MC did not inhibit the formation of osteoclast-like cells from mouse spleen cells which was supported by the exogenous soluble RANKL and M-CSF. 3MC did not affect the formation of an actin ring and pits on slices of dentine by osteoclast-like cells, both of which are typical indices of osteoclast activity. These results suggest that 3MC affects osteoclast-supporting cells such as ST2 cells but not osteoclast precursor cells and mature osteoclastic cells. When we measured the expression levels of RANKL mRNA in ST2 cells, 3MC dose-dependently decreased the level of this mRNA. However, 3MC did not affect levels of mRNAs for osteoprotegerin (OPG), M-CSF, and the receptor of 1alpha,25(OH)(2) Vitamin D(3) in ST2 cells. Furthermore, soluble RANKL was able to counteract the inhibitory effect of 3MC on the formation of osteoclast-like cells. Our findings indicate that 3MC inhibits osteoclastogenesis via the inhibition of RANKL expression in osteoblastic cells.
authors.affiliation: Department of Biological Sciences, Tokyo Institute of Technology, 226-8501, Yokohama, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Naruse
authors.forename: E
authors.initials: E
authors.lastname: Otsuka
authors.forename: M
authors.initials: M
authors.lastname: Naruse
authors.forename: Y
authors.initials: Y
authors.lastname: Ishihara
authors.forename: S
authors.initials: S
authors.lastname: Miyagawa-Tomita
authors.forename: H
authors.initials: H
authors.lastname: Hagiwara
mesh_terms: D000818:Animals; D002273:Carcinogens / Q000494:pharmacology; D002352:Carrier Proteins / Q000378:metabolism*; D004347:Drug Interactions; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008748:Methylcholanthrene / Q000494:pharmacology*; D051379:Mice; D010010:Osteoclasts / Q000187:drug effects* / Q000378:metabolism; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D018336:Receptors, Aryl Hydrocarbon / Q000819:agonists* / Q000037:antagonists & inhibitors / Q000378:metabolism; D000077185:Resveratrol; D013267:Stilbenes / Q000494:pharmacology
chemical_list: D002273:Carcinogens; D002352:Carrier Proteins; D008562:Membrane Glycoproteins; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D018336:Receptors, Aryl Hydrocarbon; D013267:Stilbenes; C505687:Tnfrsf11a protein, mouse; C505689:Tnfsf11 protein, mouse; D008748:Methylcholanthrene; D000077185:Resveratrol