title: Adiponectin receptors are present in RANK-L-induced multinucleated osteoclast-like cells.
abstract: Adiponectin is an adipokine that has been related to bone metabolism. Data on adiponectin receptors (AdipoR1, -R2) in osteoclasts have shown discrepancies. In this study we carried out observations of AdipoR1, -R2 in peripheral blood mononuclear cells that were induced to differentiate into osteoclasts. AdipoR1, -R2 were screened using reverse transcription and quantitative PCR and immunofluorescence. Acid phosphatase and Cathepsin-K were evaluated as osteoclastic markers. Results showed that acid phosphatase was expressed from day 1 whereas Cathepsin-K started from day 7. AdipoR1 and -R2 showed expression from day 1, with greater expression for AdipoR1 than AdipoR2. The immunofluorescent patterns were observed in the cells cultured under three different conditions: non-supplemented medium, added M-CSF, or medium with M-CSF, and RANK-L. The non-supplemented control did not display specific fluorescence whereas specific and strong signals were detected in cells cultured with combined M-CSF and RANK-L from day 7. The fluorescence patterns were detected mainly at the periphery of the cells, and in the cytoplasm, showing a localized patchy pattern for both receptors. In contrast, a diffuse fluorescent pattern was detected in the cytoplasm of the cells with M-CSF alone. In summary, AdipoR1 and -R2 were detected by quantitative PCR and immunofluorescence. The immunofluorescence patterns suggest that adiponectin receptors are located, or re-located, in the plasma membrane with distribution in the cytoplasm when mononuclear cells are committed to differentiate to osteoclasts. These findings could be a reasonable explanation for the controversy found in the published literature regarding the role of adiponectin in bone metabolism.
authors: Escuela de Medicina, Universidad Anahuac Mayab, Merida , Yucatan , Mexico .
authors: Elda L
authors: EL
authors: Pacheco-Pantoja
authors: Victoria J
authors: VJ
authors: Waring
authors: Peter J M
authors: PJ
authors: Wilson
authors: William D
authors: WD
authors: Fraser
authors: James A
authors: JA
authors: Gallagher
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D052242:Adiponectin / Q000235:genetics / Q000378:metabolism; D056657:Cathepsin K / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics*; D002462:Cell Membrane / Q000378:metabolism; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000166:cytology*; D016173:Macrophage Colony-Stimulating Factor / Q000378:metabolism; D010010:Osteoclasts / Q000166:cytology / Q000378:metabolism; D053245:RANK Ligand / Q000378:metabolism*; D054419:Receptors, Adiponectin / Q000378:metabolism*
chemical_list: C475418:ADIPOR1 protein, human; C475420:ADIPOR2 protein, human; D052242:Adiponectin; D053245:RANK Ligand; D054419:Receptors, Adiponectin; C505688:TNFSF11 protein, human; D016173:Macrophage Colony-Stimulating Factor; D000135:Acid Phosphatase; D056657:Cathepsin K