1999 Fiscal Year Final Research Report Summary
Cloning and functional analysis of specific molecules of osteoclast
| Project/Area Number |
09557086
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Hematology
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| Research Institution | Kumamoto University |
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Principal Investigator |
SUDA Toshio Kumamoto University School of Medicine, Professor, 医学部, 教授 (60118453)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAGUCHI Yuji Kumamoto University School of Medicine, Assistant Professor, 医学部, 講師 (00220286)
TAKAKURA Nobuyuki Kumamoto University School of Medicine, Assistant Professor, 医学部, 講師 (80291954)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Osteoclasts / STK / osteoblasts / TYRO3 / c-KitィイD1+ィエD1Mac-1ィイD1dullィエD1c-FmsィイD1+ィエD1 cells / RANK / M-CSF / RANKL |
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| Research Abstract |
Bone is continuously forming and being resorbed. This process is accomplished by precise coordination of two cell types: osteoblasts, which deposit the calcified bone matrix, and osteoclasts, which derived from hematopoietic stem cells and resorb the bone tissue. Mononuclear osteoclasts differentiate from the same precursor cells as macrophages and fuse with each other to become multinuclear osteoclasts. To clarify the differentiation of osteoclasts from precursors and their relationship to macrophage precursors, we have analyzed the functions of osteoclast-specific genes.
At first we have shown that STK and TYRO 3 receptor tyrosine kinases are expressed on osteoclasts and that they are involved in the bone resorption in the presence of each ligand, MSP and GAS6, respectively.
Next, by using FACS, we identified c-KitィイD1+ィエD1Mac-1ィイD1dullィエD1c-Fms (M-CSFR)ィイD1+ィエD1 cells in murine bone marrow as precursor cells. C-KitィイD1+ィエD1Mac-1ィイD1dullィエD1c-FmsィイD1+ィエD1 cells differentiate into c- FmsィイD1+ィエD1 cells in 2 days' co-culture with ST-2 stromal cells. We investigated the commitment process of c-KitィイD1+ィエD1Mac-1ィイD1dullィエD1c-FmsィイD1+ィエD1 cells to osteoclasts in the presence of M-CSF and soluble RANK-ligand (sRANKL) instead of stromal cells. M-CSF affect c-KitィイD1+ィエD1Mac-1ィイD1dullィエD1c-FmsィイD1+ィエD1 cells to induce RANK in 24 hrs at mRNA and protein level. These cells can differentiate into osteoclasts in the co-presence of M-CSF and sRANKL. In the presence of only M-CSF, they did differentiate into macrophages. Delayed addition of RANKL revealed that expression of RANK receptor and immediate binding of RANK-ligand is critical for osteoclast differentiation. Thus, the RANK-RANKL system determines the osteoclast differentiation of bipotential precursors in the default pathway of macrophagic differentiation.
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