Tags

Type your tag names separated by a space and hit enter

TRAF2 is essential for TNF-alpha-induced osteoclastogenesis.
J Bone Miner Res. 2005 May; 20(5):840-7.JB

Abstract

TRAF2-deficient mice show embryonic lethality, and we developed a new in vitro differentiation system to show the function of TRAF2 in osteoclastogenesis, in which osteoclast progenitors are derived from the fetal liver of TRAF2-deficient mice. Using this system, we showed that TRAF2 is required for TNF-alpha-induced osteoclastogenesis.

INTRODUCTION

TNF receptor-associated factor 2 (TRAF2) is a signal transducer for RANK and for two TNF receptor isotypes, TNFR1 and TNFR2. Because TRAF2-deficient mice show embryonic lethality, it has remained unclear whether TRAF2 is crucial in RANKL- or TNF-alpha-induced osteoclastogenesis.

MATERIALS AND METHODS

Osteoclast progenitors derived from fetal liver were cultured in the presence of monocyte macrophage colony-stimulating factor (M-CSF), and flow cytometry for characterization of surface markers on these cells was performed. To examine the involvement of TRAF2 in osteoclast differentiation, we cultured osteoclast progenitors from TRAF2-deficient and wildtype mice with soluble RANKL or TNF-alpha in the presence of M-CSF, and counted the number of TRACP(+) multinucleate cells formed. c-jun N-terminal kinase (JNK) and NF-kappaB activation in osteoclast progenitors was examined by Western blot analysis and electrophoretic mobility shift assay, respectively. Nuclear factor of activated T cells (NFATc1) expression and activation were analyzed by RT-PCR and immunofluorescence staining, respectively. To examine whether TRAF2 overexpression induced osteoclastogenesis, TRAF2 was overexpressed in osteoclast progenitors form wildtype bone marrow by retrovirus infection.

RESULTS AND CONCLUSIONS

Osteoclast progenitors from normal fetal liver, which were cultured with M-CSF, expressed surface molecules c-fms, Mac-1, and RANK, and could differentiate into TRACP(+) multinucleate cells in the presence of soluble RANKL or TNF-alpha. RANKL-induced osteoclastogenesis gave a reduction of 20% in the progenitors from TRAF2-deficient mice compared with that of the cells from littermate wildtype mice, whereas TNF-alpha-induced osteoclastogenesis was severely impaired in the cells from the TRAF2-deficient mice. Only a few TRACP(+) multinucleate cells were formed, and TNF-alpha-mediated activation of JNK, NF-kappaB, and NFATc1 was defective. TRAF2 overexpression induced differentiation of osteoclast progenitors from wildtype mice into TRACP(+) multinucleate cells. These results suggest that TRAF2 plays an important role in TNF-alpha-induced osteoclastogenesis.

Authors+Show Affiliations

Department of Life Science, Tokyo Institute of Technology, Yokohama, Japan.No affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15824857

Citation

Kanazawa, Kiyoshi, and Akira Kudo. "TRAF2 Is Essential for TNF-alpha-induced Osteoclastogenesis." Journal of Bone and Mineral Research : the Official Journal of the American Society for Bone and Mineral Research, vol. 20, no. 5, 2005, pp. 840-7.
Kanazawa K, Kudo A. TRAF2 is essential for TNF-alpha-induced osteoclastogenesis. J Bone Miner Res. 2005;20(5):840-7.
Kanazawa, K., & Kudo, A. (2005). TRAF2 is essential for TNF-alpha-induced osteoclastogenesis. Journal of Bone and Mineral Research : the Official Journal of the American Society for Bone and Mineral Research, 20(5), 840-7.
Kanazawa K, Kudo A. TRAF2 Is Essential for TNF-alpha-induced Osteoclastogenesis. J Bone Miner Res. 2005;20(5):840-7. PubMed PMID: 15824857.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - TRAF2 is essential for TNF-alpha-induced osteoclastogenesis. AU - Kanazawa,Kiyoshi, AU - Kudo,Akira, Y1 - 2004/12/20/ PY - 2004/08/23/received PY - 2004/11/10/revised PY - 2004/12/14/accepted PY - 2005/4/13/pubmed PY - 2005/8/20/medline PY - 2005/4/13/entrez SP - 840 EP - 7 JF - Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research JO - J Bone Miner Res VL - 20 IS - 5 N2 - UNLABELLED: TRAF2-deficient mice show embryonic lethality, and we developed a new in vitro differentiation system to show the function of TRAF2 in osteoclastogenesis, in which osteoclast progenitors are derived from the fetal liver of TRAF2-deficient mice. Using this system, we showed that TRAF2 is required for TNF-alpha-induced osteoclastogenesis. INTRODUCTION: TNF receptor-associated factor 2 (TRAF2) is a signal transducer for RANK and for two TNF receptor isotypes, TNFR1 and TNFR2. Because TRAF2-deficient mice show embryonic lethality, it has remained unclear whether TRAF2 is crucial in RANKL- or TNF-alpha-induced osteoclastogenesis. MATERIALS AND METHODS: Osteoclast progenitors derived from fetal liver were cultured in the presence of monocyte macrophage colony-stimulating factor (M-CSF), and flow cytometry for characterization of surface markers on these cells was performed. To examine the involvement of TRAF2 in osteoclast differentiation, we cultured osteoclast progenitors from TRAF2-deficient and wildtype mice with soluble RANKL or TNF-alpha in the presence of M-CSF, and counted the number of TRACP(+) multinucleate cells formed. c-jun N-terminal kinase (JNK) and NF-kappaB activation in osteoclast progenitors was examined by Western blot analysis and electrophoretic mobility shift assay, respectively. Nuclear factor of activated T cells (NFATc1) expression and activation were analyzed by RT-PCR and immunofluorescence staining, respectively. To examine whether TRAF2 overexpression induced osteoclastogenesis, TRAF2 was overexpressed in osteoclast progenitors form wildtype bone marrow by retrovirus infection. RESULTS AND CONCLUSIONS: Osteoclast progenitors from normal fetal liver, which were cultured with M-CSF, expressed surface molecules c-fms, Mac-1, and RANK, and could differentiate into TRACP(+) multinucleate cells in the presence of soluble RANKL or TNF-alpha. RANKL-induced osteoclastogenesis gave a reduction of 20% in the progenitors from TRAF2-deficient mice compared with that of the cells from littermate wildtype mice, whereas TNF-alpha-induced osteoclastogenesis was severely impaired in the cells from the TRAF2-deficient mice. Only a few TRACP(+) multinucleate cells were formed, and TNF-alpha-mediated activation of JNK, NF-kappaB, and NFATc1 was defective. TRAF2 overexpression induced differentiation of osteoclast progenitors from wildtype mice into TRACP(+) multinucleate cells. These results suggest that TRAF2 plays an important role in TNF-alpha-induced osteoclastogenesis. SN - 0884-0431 UR - https://www.unboundmedicine.com/medline/citation/15824857/TRAF2_is_essential_for_TNF_alpha_induced_osteoclastogenesis_ L2 - https://doi.org/10.1359/JBMR.041225 DB - PRIME DP - Unbound Medicine ER -