title: Regucalcin stimulates osteoclast-like cell formation in mouse marrow cultures.
abstract: The effect of regucalcin, a regulatory protein in intracellular signaling, on osteoclastic cell formation in mouse bone marrow culture is investigated. The bone marrow cells were cultured for 7 days in an alpha-minimal essential medium containing either vehicle or regucalcin (10(-10)-10(-8)M). Osteoclast-like cell formation was estimated by staining for tartrate-resistant acid phosphatase (TRACP), a marker enzyme of osteoclasts. The presence of regucalcin (10(-10)-10(-8)M) caused a remarkable increase in osteoclast-like multinucleated cells (MNCs). The effect of regucalcin in stimulating osteoclast-like cell formation was significantly inhibited in the presence of calcitonin (CT; 10(-9)M), 17beta-estradiol (10(-9)M), beta-cryptoxanthin (CX; 10(-6)M), or zinc sulfate (10(-4)M), which is an anti-bone resorbing factor. The effect of regucalcin on osteoclast-like cell formation was not significantly blocked in the presence of cycloheximide, an inhibitor of protein synthesis, or 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB), an inhibitor of transcriptional activity. The effect of parathyroid hormone (10(-7)M), 1,25-dihydroxyvitamin D(3) (10(-7)M), prostaglandin E(2) (10(-5)M), or tumor necrosis factor-alpha (10 ng/ml) in increasing osteoclast-like cell formation was significantly enhanced in the presence of regucalcin (10(-8)M). Moreover, when rat femoral-diaphyseal or -metaphyseal tissues were cultured for 48 h in the presence of regucalcin (10(-10)-10(-8)M), the diaphyseal or metaphyseal calcium content was significantly decreased in the presence of regucalcin (10(-10)-10(-8)M) in vitro. The consumption of glucose and the production of lactic acid in culture medium by the diaphyseal or metaphyseal tissues was significantly raised in the presence of regucalcin (10(-10)-10(-8)M). This study demonstrates that regucalcin directly stimulates osteoclast-like cell formation in mouse marrow culture in vitro, and that the protein stimulates bone resorption in rat femoral tissues in vitro.
authors.affiliation: Laboratory of Endocrinology and Molecular Metabolism, Graduate School of Nutritional Sciences, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan. yamaguch@u-shizuoka-ken.ac.jp
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Yamaguchi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Uchiyama
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D002135:Calcium-Binding Proteins; D002265:Carboxylic Ester Hydrolases; D002454:Cell Differentiation / Q000187:drug effects*; D002478:Cells, Cultured; D015232:Dinoprostone / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D051379:Mice; D010010:Osteoclasts / Q000166:cytology* / Q000187:drug effects*; D011506:Proteins / Q000494:pharmacology*; D051381:Rats; D015238:Sulfotransferases; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D002135:Calcium-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D011506:Proteins; C513324:Rgn protein, mouse; D014409:Tumor Necrosis Factor-alpha; D015238:Sulfotransferases; C028152:alcohol sulfotransferase; D002265:Carboxylic Ester Hydrolases; C513325:Rgn protein, rat; D005947:Glucose; D015232:Dinoprostone