Functional Analysis of Cnot3 in Regulation of Bone Metabolism
It is becoming well known that bone metabolism is a key factor for orthodontic tooth movement. It is widely accepted that gene expression is regulated by post-transcriptional and transcriptional control. Cnot3 is a component of Ccr4-not complex which post-transcriptionally regulates gene expression by degradation of mRNAs. However, the role of Cnot3 in bone metabolism is barely understood. Objectives: To determine the role of Cnot3 in bone mass regulation. Methods: Bone structure of the Cnot3+/- mice (14 weeks and 2 years old male mice) were examined since -/- is embryonic lethal. We performed µCT analysis and histomorphometry of bone using calcein labeling and TRAP staining. For in vitro experiments, we used bone marrow cells derived from Cnot3+/- mice, RAW264.7 (osteoclast precursor) and MC3T3-E1 (osteoblastic) cell lines. Results: We found that Cnot3 mRNA was expressed in adult bone, in RAW264.7 and MC3T3-E1 cells. Cnot3+/- mice (14 weeks old) showed low bone mineral density and reduced levels in bone volume per tissue volume in 3D µCT analysis. Osteoclast number and bone formation rate were increased in Cnot3+/- mice. Therefore, Cnot3+/- mice exhibited high turnover type bone loss. In age-induced osteoporosis model, Cnot3+/- mice (2 years old) further exacerbated the bone loss. Thus, aging enhanced Cnot3 haploinsufficiency-induced reduction in bone mass.Cnot3 +/- mice revealed enhanced number of TRAP positive multinucleated cells in bone marrow cell cultures. This suggests cell-autonomous effects of Cnot3 haploinsufficiency. Messenger RNA levels related to osteoclastic activity such as M-CSF in MC3T3-E1 and RANK in RAW264.7 were up-regulated when Cnot3 was knocked down using siRNA. Furthermore, TRAP biochemical activity was higher in Cnot3 deficient RAW264.7 cells treated with RANKL. Conclusion: Cnot3 is required for maintenance of the bone mass at least in part through suppression of osteoclastogenesis.
Division: IADR/AADR/CADR General Session
Meeting:2013 IADR/AADR/CADR General Session (Seattle, Washington) Location: Seattle, Washington
Year: 2013 Final Presentation ID:2291 Abstract Category|Abstract Category(s):IADR/Unilever Hatton Awards
Authors
Watanabe, Chiho
( Tokyo Medical & Dental University, Tokyo, N/A, Japan
)
Morita, Masahiro
( Institute of Medical Science, The University of Tokyo, Tokyo, N/A, Japan
)
Ezura, Yoichi
( Tokyo Medical & Dental University, Tokyo, N/A, Japan
)
Hayata, Tadayoshi
( Tokyo Medical & Dental University, Tokyo, N/A, Japan
)
Nakamoto, Tetsuya
( Tokyo Medical & Dental University, Tokyo, N/A, Japan
)
Notomi, Takuya
( Tokyo Medical & Dental University, Tokyo, N/A, Japan
)
Yamamoto, Tadashi
( Institute of Medical Science, The University of Tokyo, Tokyo, N/A, Japan
)
Noda, Masaki
( Tokyo Medical & Dental University, Tokyo, N/A, Japan
)
Moriyama, Keiji
( Tokyo Medical & Dental University, Tokyo, N/A, Japan
)