2003 Fiscal Year Final Research Report Summary
Osteoclast Differentiation initiated at late-stage of mitosisof progenitor cells : Molecular mechanism of divergence from cell cycle
| Project/Area Number |
14571738
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Morphological basic dentistry
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| Research Institution | Kyushu University |
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Principal Investigator |
KUKITA Toshio Kyushu University, Facult.Dental Science, Associate Professor, 歯学研究院, 助教授 (70150464)
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| Co-Investigator(Kenkyū-buntansha) |
NAGATA Kengo Kyushu University, Facult.Dental Science, Research Associate, 歯学研究院, 助手 (90189134)
KUKITA Akiko Saga Medical School, Associate Professor, 医学部, 助教授 (30153266)
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| Project Period (FY) |
2002 – 2003
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| Keywords | osteoclast / differentiation / proliferation of precursors / M-phase / cell surface antigen / affinity chromatography / mass-spectrometry / RAW-D cells |
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| Research Abstract |
Osteoclasts are multinucleated giant cells and it has been elucidated that mononuclear osteoclast precursors fuse each other to form multinucleated cells. Under the bone microenvironment composed of RANKL and other factors, osteoclastoprogenitors proliferate to differentiate into real osteoclasts, however, it has been ambiguous concerning the exact point of divergence into osteoclast-lineage in cell cycle. Previously we found the osteoclast-specific membrane molecule Kati-antigen expressed on rat osteoclasts. When we examined initiation of osteoclastogenesis using anti-Kati-antigen monoclonal antibody (mAb Kat1) as the tracer of osteoclastogenesis, we found an interesting observation in which Kati-antigen was expressed only in one daughter cells of dividing cells at the postmitotic phase of osteoclast progenitors. Mab Kati also reacts with rat astrocytic cell line RCR-1 cells. If the cell cycle of RCR-1 cells was synchronized to mitosis by treatment with colcemid, numerous RCR-1 cells in mitotic phase expressed Kati-antigen. Morphological analysis revealed that Kati-antigen was expressed only in one daughter cells of dividing cells at the postmitotic phase of RCR-1 cells in a similar pattern as osteoclast progenitors. As it was suggested that Kati-antigen is the receptor molecule determining the differentiation fate of the progenitors, we focused on elucidating the entity of this antigen and obtained data which suggest, that Kat-1 antigen was a related molecule with galectin 3. To separate postmitotic osteoclast progenitors into Kat1-positve cells and Kat1-negative cells was quite difficult in terms of experimental technology, and therefore we could not compare mRNA expression profiles among these two cell fractions. Now we are trying to construct M-phase specific cDNA library by use of RAW-D cells synchronized to M-phase. This study would enable an establishment of novel strategy of regulating bone resorption through targeting osteoclast progenitors in M-phase.
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