Limits...
FOXO1 inhibits osteoclastogenesis partially by antagnozing MYC.

Tan P, Guan H, Xie L, Mi B, Fang Z, Li J, Li F - Sci Rep (2015)

Bottom Line: Intriguingly, recent studies on the role played by FOXOs in osteoclastogenesis reached different conclusion.We found that FOXO1 inhibition modulated MAPKs, NF-κB and AP-1.To conclude, our study confirmed FOXO1 as a cell-autonomous inhibitor of osteoclastogenesis.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.

ABSTRACT
FOXO transcription factors especially FOXO1 have profound roles in bone development and remodeling. The regulation of cells of the osteoblast lineage by FOXOs is suggested to be stage-specific or context dependent. Intriguingly, recent studies on the role played by FOXOs in osteoclastogenesis reached different conclusion. Bartell et al. showed that FOXOs restrained osteoclastogenesis and bone resorption partially by upregulation of the H2O2-inactivating enzyme catalase. Wang et al. demonstrated that FOXO1 activated osteoclast formation. In the present study, we confirmed the results of Bartell et al. that FOXO1 expression was reduced upon stimulation of RANKL; FOXO1 inhibition promoted and FOXO1 activation repressed, osteoclast differentiation and activity; the inhibitory effect of FOXO1 on osteoclastogenesis was partially mediated by ROS since treatment with ROS scavengers cancelled the effect of FOXO1 inhibition on osteoclastogenesis. We further investigated the mechanisms responsible for repressed osteoclastogenesis by FOXO1. We found that FOXO1 inhibition modulated MAPKs, NF-κB and AP-1. Finally, we proved that the inhibitory effect of FOXO1 on osteoclast formation was partially mediated by MYC suppression by showing that MYC repression almost totally abrogated the effect of FOXO1 inhibition on osteoclastogenesis. To conclude, our study confirmed FOXO1 as a cell-autonomous inhibitor of osteoclastogenesis.

No MeSH data available.


Related in: MedlinePlus

FOXO1 expression in RANKL stimulated BMMCs and RAW264.7 cells.(A,B) BMMCs were treated with M-CSF (30 ng/ml) and RANKL (50 ng/ml), RAW264.7 cells were treated with RANKL (50 ng/ml), the expression of FOXO1 was examined by real-time PCR. Data are mean ± SD of target gene to reference gene (FOXO1/β-actin) ratio. (C,D) Expression of FOXO1 protein in RAW264.7 cells incubated with RANKL (50 ng/ml) was assessed by Immunoblot. ACTB was used as a loading control. Band densities were quantified and normalized to the control. Data was presented as mean ± SD of 3 independent experiments. *P < 0.05 versus 0 day group.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4645183&req=5

f1: FOXO1 expression in RANKL stimulated BMMCs and RAW264.7 cells.(A,B) BMMCs were treated with M-CSF (30 ng/ml) and RANKL (50 ng/ml), RAW264.7 cells were treated with RANKL (50 ng/ml), the expression of FOXO1 was examined by real-time PCR. Data are mean ± SD of target gene to reference gene (FOXO1/β-actin) ratio. (C,D) Expression of FOXO1 protein in RAW264.7 cells incubated with RANKL (50 ng/ml) was assessed by Immunoblot. ACTB was used as a loading control. Band densities were quantified and normalized to the control. Data was presented as mean ± SD of 3 independent experiments. *P < 0.05 versus 0 day group.

Mentions: We examined FOXO1 expression in BMMCs and RAW264.7 cells during osteoclastogenesis by quantitative real-time PCR. FOXO1 expression was decreased in BMMCs and RAW264.7 cells upon treatment of RANKL (Fig. 1A,B). The decrease was most significant at 3 days after RANKL incubation in BMMCs and 2 days in RAW264.7 cells. The expression of FOXO1 in osteoclastogenesis was also measured by Immunoblot in RAW264.7 cells. Similarly, RANKL decreased FOXO1 protein levels in RAW264.7 cells (Fig. 1C,D).


FOXO1 inhibits osteoclastogenesis partially by antagnozing MYC.

Tan P, Guan H, Xie L, Mi B, Fang Z, Li J, Li F - Sci Rep (2015)

FOXO1 expression in RANKL stimulated BMMCs and RAW264.7 cells.(A,B) BMMCs were treated with M-CSF (30 ng/ml) and RANKL (50 ng/ml), RAW264.7 cells were treated with RANKL (50 ng/ml), the expression of FOXO1 was examined by real-time PCR. Data are mean ± SD of target gene to reference gene (FOXO1/β-actin) ratio. (C,D) Expression of FOXO1 protein in RAW264.7 cells incubated with RANKL (50 ng/ml) was assessed by Immunoblot. ACTB was used as a loading control. Band densities were quantified and normalized to the control. Data was presented as mean ± SD of 3 independent experiments. *P < 0.05 versus 0 day group.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4645183&req=5

f1: FOXO1 expression in RANKL stimulated BMMCs and RAW264.7 cells.(A,B) BMMCs were treated with M-CSF (30 ng/ml) and RANKL (50 ng/ml), RAW264.7 cells were treated with RANKL (50 ng/ml), the expression of FOXO1 was examined by real-time PCR. Data are mean ± SD of target gene to reference gene (FOXO1/β-actin) ratio. (C,D) Expression of FOXO1 protein in RAW264.7 cells incubated with RANKL (50 ng/ml) was assessed by Immunoblot. ACTB was used as a loading control. Band densities were quantified and normalized to the control. Data was presented as mean ± SD of 3 independent experiments. *P < 0.05 versus 0 day group.
Mentions: We examined FOXO1 expression in BMMCs and RAW264.7 cells during osteoclastogenesis by quantitative real-time PCR. FOXO1 expression was decreased in BMMCs and RAW264.7 cells upon treatment of RANKL (Fig. 1A,B). The decrease was most significant at 3 days after RANKL incubation in BMMCs and 2 days in RAW264.7 cells. The expression of FOXO1 in osteoclastogenesis was also measured by Immunoblot in RAW264.7 cells. Similarly, RANKL decreased FOXO1 protein levels in RAW264.7 cells (Fig. 1C,D).

Bottom Line: Intriguingly, recent studies on the role played by FOXOs in osteoclastogenesis reached different conclusion.We found that FOXO1 inhibition modulated MAPKs, NF-κB and AP-1.To conclude, our study confirmed FOXO1 as a cell-autonomous inhibitor of osteoclastogenesis.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.

ABSTRACT
FOXO transcription factors especially FOXO1 have profound roles in bone development and remodeling. The regulation of cells of the osteoblast lineage by FOXOs is suggested to be stage-specific or context dependent. Intriguingly, recent studies on the role played by FOXOs in osteoclastogenesis reached different conclusion. Bartell et al. showed that FOXOs restrained osteoclastogenesis and bone resorption partially by upregulation of the H2O2-inactivating enzyme catalase. Wang et al. demonstrated that FOXO1 activated osteoclast formation. In the present study, we confirmed the results of Bartell et al. that FOXO1 expression was reduced upon stimulation of RANKL; FOXO1 inhibition promoted and FOXO1 activation repressed, osteoclast differentiation and activity; the inhibitory effect of FOXO1 on osteoclastogenesis was partially mediated by ROS since treatment with ROS scavengers cancelled the effect of FOXO1 inhibition on osteoclastogenesis. We further investigated the mechanisms responsible for repressed osteoclastogenesis by FOXO1. We found that FOXO1 inhibition modulated MAPKs, NF-κB and AP-1. Finally, we proved that the inhibitory effect of FOXO1 on osteoclast formation was partially mediated by MYC suppression by showing that MYC repression almost totally abrogated the effect of FOXO1 inhibition on osteoclastogenesis. To conclude, our study confirmed FOXO1 as a cell-autonomous inhibitor of osteoclastogenesis.

No MeSH data available.


Related in: MedlinePlus