| Project/Area Number |
13470304
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Orthopaedic surgery
|
|---|
| Research Institution | The University of Tokyo |
|---|
Principal Investigator |
OHNISHI Isao The University of Tokyo, Faculty of Medicine, Lecturer, 医学部附属病院, 講師 (70311628)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
INOUE Jun-ichiro The University of Tokyo, The institute of Medical Science, Professor, 医科学研究所, 教授 (70176428)
ODA Hiromi The University of Tokyo, Faculty of Medicine, Associate Professor, 医学部附属病院, 助教授 (60101698)
TANAKA Sakae The University of Tokyo, Faculty of Medicine, Lecturer, 医学部附属病院, 講師 (50282661)
|
|---|
| Project Period (FY) |
2001 – 2003
|
| Project Status |
Completed (Fiscal Year 2003)
|
| Budget Amount *help |
¥9,400,000 (Direct Cost: ¥9,400,000)
Fiscal Year 2003: ¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2002: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 2001: ¥4,300,000 (Direct Cost: ¥4,300,000)
|
|---|
| Keywords | Osteoclast / RANKL / TRAFG / IL-1 / IL-1 |
|---|
| Research Abstract |
Signals emanating from the receptor for interleukin-1 (IL-1) and receptor activator of NF kappa B ligand (RANKL) stimulate transcription factors AP-1 through mitogen-activated protein kinase (MAPK) activation and NF kappa B through I kappa B kinase (IKK) activation. These kinases are thought to be activated by tumor necrosis factor receptor-associated factor 6 (TRAF6). However, molecular mechanisms by which TRAFG activates various downstream kinases remain to be elucidated. We identified functional domains of TRAF6 under physiological conditions established by appropriate expression of TRAF6 mutants in TRAF6-deficient cells. The RING finger domain is not required for differentiation of splenocytes to multinuclear osteoclasts, but is essential for osteoclast maturation. Thus, TRAF6 plays essential roles in both the differentiation and maturation of osteoclasts by activating various kinases via its multiple domains. We next examined the relationship between IL-1/TRAF6-dependent and c-Src-mediated pathways in the activation of osteoclast-like cells (prefusion cells (pOCs); multinucleated cells) formed in the murine eoculture system. In normal pOCs treated with IL-1, anti-TRAF6 antibodies coprecipitate p130(Cas), protein tyrosine kinase 2, and c-Src. In Src-deficient pOCs, this molecular complex was not detected, suggesting that c-Src is required for formation of the TRAFG, p130(Cas), and protein tyrosine kinase 2 complex. Moreover, an immunocytochemical analysis revealed that in osteoclast-Like multinucleated cells, IL-1 induced redistribution of TRAF6 to actin ring structures formed at the cell periphery, where TRAF6 also colocalized with c-Src. Taken together, these data suggest that IL-I signals feed into the tyrosine kinase pathways through a TRAF6-Src molecular complex, which regulates the cytoskeletal reorganization essential for osteoclast activation.
|
