| Co-Investigator(Kenkyū-buntansha) |
UDAGAWA Nobuyuki School of Dentistry, Assistant, 歯学部, 助手 (70245801)
MIYAURA Chisato School of Dentistry, Lecturer, 歯学部, 講師 (20138382)
TAKAHASHI Naoyuki School of Dentistry, Associate Professor, 歯学部, 助教授 (90119222)
SHINKI Toshimasa School of Dentistry, Lecturer, 歯学部, 講師 (90138420)
ABE Etsuko School of Dentistry, Associate Professor, 歯学部, 助教授 (70119147)
金 成河 昭和大学, 歯学部, 助手 (10205049)
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| Budget Amount *help |
¥27,000,000 (Direct Cost: ¥27,000,000)
Fiscal Year 1993: ¥4,000,000 (Direct Cost: ¥4,000,000)
Fiscal Year 1992: ¥23,000,000 (Direct Cost: ¥23,000,000)
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| Research Abstract |
25-Hydroxyvitamin D_3 [25(OH)D_3] is metabolized primarily in the kidney to either 1alpha, 25(OH)_2D_3 [1alpha, 25(OH)_2D_3] or 24,25-dihydroxyvitamin D_3 [24,25(OH)_2D_3] by the mitochndrial enzymes 1alpha-hydroxylase and 24-hydrxylase. In order to investigate the regulation of vitamin D metabolism, we have partially purified the 25(OH)D_3 1alpha-hydroxylase from the kidney. The chick mitochondrial cytochrome P-450, 1alpha, 25(OH)_2D_3 24-hydroxylase was partially purified sequential polyethylene glycol precipitation, aminopentyl-Sepharose 4B, CM-cellulose, and hydroxyapatite chromatography. The turnover rate of the final preparation, when reconstituted with NADPH, adrenodoxin, and adrenodoxin reductase, was more than 4. The urified protein was finally aplied to SDS-PAGE under a reducing condition. The proteins on the gels were stained with Coomassie brilliant blue and transferred onto Immobilon by electroblotting, and their N-terminal sequences were determined using a protein sequenc
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It has been reported that soluble interleukin-6 receptor (sIL-6R) is detected in the serum of healthy individuals and its level is increased in patients with multiple myeloma and huma immunodeficiency virus infection. Although several reports have suggested that sIL-6R potentiates IL-6 action, its hysilogical role remains unclear. In this study, we examined the role of sIL-6R on osteoclast formation by IL-6, using a coculture of mouse osteoblasts and bone marrow cells. Neither recombinant muse IL-6 (mIL-6) nor mouse sIL-6R (smIL-6) induced osteoclast-like multinucleated cell (MNC) formation when they were added separately. In cntrast, simultaneous treatment with mIL-6 and smIL-6R strikingly induced MNC formation. These MNCs satisfied major criteria of authentic osteoclasts, such as tartrateresistant acid phosphatase (TRAP) activity, calcitonin receptors, and pit formation n dentine slices. The MNC formation induced by mIL-6 and smIL-6R was dose-dependently inhibited by adding mnoclonal anti-mouse IL-6R antibody. It is likely that osteoblasts and osteoclast progenitors are capable of transducing a signal from a complex of IL-6 and sIL-6R through gp130, even though they may have no or a very small number of IL-6Rs. Factors such as IL-11, oncotatin M, and leukemia inhibitory factor, which are known to exert their functons through gp130 (the signaltransducing chain of IL-6R), also induced MNC formation in our coculture system. These results suggest that increased circulating or locally produced SIL-6R induces osteoclast formation in the presence of IL-6 mediated by a mechanissm involving gp130. This may play an important physiological or pathological role in conditions associated with increased osteoclastic bone resorption. Less
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