1991 Fiscal Year Final Research Report Summary
Cell biological studies on cell-cell, cell-matrix interaction in bone metabolism.
| Project/Area Number |
02404071
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Morphological basic dentistry
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| Research Institution | Niigata University. |
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Principal Investigator |
OZAWA Hidehiro Niigata University, School of Dentistry, Professor., 歯学部, 教授 (60018413)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Hiroaki Niigata University, School of Dentistry, Research Associate., 歯学部, 助手 (50227930)
IRIE Kazuharu Niigata University, School of Dentistry, Research Associate., 歯学部, 助手 (70223352)
EJIRI Sadakazu Niigata University, School of Dentistry, Associate Professor., 歯学部, 助教授 (40160361)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Osteoclasts / Osteoblasts / Calcitonin / Vitamine D3 Receptor / Carbohydrate chain / Heparan sulfate proteoglycan / Osteocytes / Intracellular Calcium |
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| Research Abstract |
We conducted 6 series of experiments on the correlation between osteoclasts and osteoblasts : 1) Changes in Ca concentration in osteoclasts was determined by fluorescence-labeling of Ca on single cells, and the effect of calcitonin on Ca movement using an Olympus OSP-3. Ca movement within osteoclasts was transiently enhanced by CT but rapidly decreased, after which the cells recovered their functional activities. The experiment was repeated on osteoclasts cultured on bone tissue, then the osteociasts were also submitted to a 2-dhnentional analysis using an Olympus CASARUS. Ca transport pathway within osteociasts and its inhibition by CT was evidenced. 2) Changes induced by CT on osteociast cytoskeleton was assessed with an Olympus IMT2-21CA3, by observing the changes in the localization of actin filametns and intermediate filaments occurring after addition of CT. 3) To clarify the differentiation of osteoclastic multinuclear giant cells (MNGCs), we cocultured osteoblasts and spleen cel
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ls in the presence of vitamin D3. The PMNGCs thus formed were TRACPasepositive and expressed CT receptors, which lead to consider them as osteociastic. Moreover, we found that a direct cell-to-cell contact with osteoblasts was required in the formation of osteoclastic MNGCs. 4) We also demonstrated by immunocytochemistry in vitro and in vivo that VDR was densely localized in the nucleus, especially in the heterochromatin, and that VDR was transported within the cytoplasm over and along microtubules to reach the nucleus. 5) We studied the interaction between differentiation/activation of osteoclasts and osteoblasts by lectin histochemistry and immunocytochemistry. Reaction of ConA, PNA, WGA, UEA-1 and MPA was intense on the membrane surface of osteoclast and osteoclasts where the two types of cells were in contact each other. The contact surface was also strongly heparan sulphate proteoglycan-positive. These two findings suggest an involvement of carbohydrate chains in the intercellular recognition between osteoclasts and osteoblasts, and to the local reservoir of growth factors and cytokines. 6) We attempted to clarify the inter-relationship between osteoclasts and osteocytes by cytochemistry, whereby we found that the latter cells enters in a cell-ceil interaction with the former : Osteocytes could promote bone resorption by this mechanism. Less
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