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ERK5 activation is essential for osteoclast differentiation.

Amano S, Chang YT, Fukui Y - PLoS ONE (2015)

Bottom Line: Therefore, activation of ERK5 is required for the induction of c-Fos.These events were confirmed in experiments using M-CSF-dependent bone marrow macrophages.Taken together, the present results show that activation of the MEK5/ERK5 pathway with M-CSF is required for osteoclast differentiation, which may induce differentiation through the induction of c-Fos.

View Article: PubMed Central - PubMed

Affiliation: Division of Microbiology and Immunology, Department of Oral Biology and Tissue Engineering, Meikai University School of Dentistry, Keyakidai, Sakado City, Japan.

ABSTRACT
The MEK/ERK pathways are critical for controlling cell proliferation and differentiation. In this study, we show that the MEK5/ERK5 pathway participates in osteoclast differentiation. ERK5 was activated by M-CSF, which is one of the essential factors in osteoclast differentiation. Inhibition of MEK5 by BIX02189 or inhibition of ERK5 by XMD 8-92 blocked osteoclast differentiation. MEK5 knockdown inhibited osteoclast differentiation. RAW264.7D clone cells, which are monocytic cells, differentiate into osteoclasts after stimulation with sRANKL. ERK5 was activated without any stimulation in these cells. Inhibition of the MEK5/ERK5 pathway by the inhibitors also blocked the differentiation of RAW264.7D cells into osteoclasts. Moreover, expression of the transcription factor c-Fos, which is indispensable for osteoclast differentiation, was inhibited by treatment with MEK5 or ERK5 inhibitors. Therefore, activation of ERK5 is required for the induction of c-Fos. These events were confirmed in experiments using M-CSF-dependent bone marrow macrophages. Taken together, the present results show that activation of the MEK5/ERK5 pathway with M-CSF is required for osteoclast differentiation, which may induce differentiation through the induction of c-Fos.

No MeSH data available.


Related in: MedlinePlus

The formation of TRAP-positive MNCs in M-BMMs was also inhibited by BIX02189 or XMD8-92.(A, B) M-BMMs were pretreated with or without BIX02189 (A) or XMD8-92 (B) for 6 hrs and then cultured in the presence of M-CSF (10 ng/ml) and sRANKL (10 ng/ml) for 7 days. The TRAP activity in culture medium diluted ten times was measured. Results are expressed as the mean ± SD of sixplicate cultures. Significant differences were examined using the Student’s t-test, *P<0.05 compared with the culture without BIX02189 or XMD8-92. (C) The viability of the cells during the experiment was measured. Similar results were obtained in two independent experiments. (D, E) The induction of c-Fos was monitored at the mRNA and protein levels. Similar results were obtained in two independent experiments. Significant differences were examined using the Student’s t-test, *P<0.05 compared with the culture with M-CSF.
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pone.0125054.g009: The formation of TRAP-positive MNCs in M-BMMs was also inhibited by BIX02189 or XMD8-92.(A, B) M-BMMs were pretreated with or without BIX02189 (A) or XMD8-92 (B) for 6 hrs and then cultured in the presence of M-CSF (10 ng/ml) and sRANKL (10 ng/ml) for 7 days. The TRAP activity in culture medium diluted ten times was measured. Results are expressed as the mean ± SD of sixplicate cultures. Significant differences were examined using the Student’s t-test, *P<0.05 compared with the culture without BIX02189 or XMD8-92. (C) The viability of the cells during the experiment was measured. Similar results were obtained in two independent experiments. (D, E) The induction of c-Fos was monitored at the mRNA and protein levels. Similar results were obtained in two independent experiments. Significant differences were examined using the Student’s t-test, *P<0.05 compared with the culture with M-CSF.

Mentions: Finally, we examined the effect of inhibition of the MEK5/ERK5 pathway on the differentiation of M-BMMs into osteoclasts. M-BMMs were stimulated with M-CSF and sRANKL for 7 days to form TRAP (+) MNCs. MEK5 and ERK5 inhibitors blocked the formation of TRAP (+) MNCs, respectively (Fig 9A and 9B). These cells were more sensitive to the drugs than 4B12 or RAW264.6D clone cells. The viability of the cells was not affected by the drug treatment (Fig 9C). The induction of c-Fos was also examined. c-Fos expression induced by M-CSF was inhibited by treatment with the MEK5 and ERK5 pathway inhibitors (Fig 9D). These results suggest that M-CSF stimulation of the MEK5/ERK5 pathway is required for the formation of osteoclasts in primary M-BMM as well as in 4B12 or RAW264.7D clone cell cultures.


ERK5 activation is essential for osteoclast differentiation.

Amano S, Chang YT, Fukui Y - PLoS ONE (2015)

The formation of TRAP-positive MNCs in M-BMMs was also inhibited by BIX02189 or XMD8-92.(A, B) M-BMMs were pretreated with or without BIX02189 (A) or XMD8-92 (B) for 6 hrs and then cultured in the presence of M-CSF (10 ng/ml) and sRANKL (10 ng/ml) for 7 days. The TRAP activity in culture medium diluted ten times was measured. Results are expressed as the mean ± SD of sixplicate cultures. Significant differences were examined using the Student’s t-test, *P<0.05 compared with the culture without BIX02189 or XMD8-92. (C) The viability of the cells during the experiment was measured. Similar results were obtained in two independent experiments. (D, E) The induction of c-Fos was monitored at the mRNA and protein levels. Similar results were obtained in two independent experiments. Significant differences were examined using the Student’s t-test, *P<0.05 compared with the culture with M-CSF.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4401765&req=5

pone.0125054.g009: The formation of TRAP-positive MNCs in M-BMMs was also inhibited by BIX02189 or XMD8-92.(A, B) M-BMMs were pretreated with or without BIX02189 (A) or XMD8-92 (B) for 6 hrs and then cultured in the presence of M-CSF (10 ng/ml) and sRANKL (10 ng/ml) for 7 days. The TRAP activity in culture medium diluted ten times was measured. Results are expressed as the mean ± SD of sixplicate cultures. Significant differences were examined using the Student’s t-test, *P<0.05 compared with the culture without BIX02189 or XMD8-92. (C) The viability of the cells during the experiment was measured. Similar results were obtained in two independent experiments. (D, E) The induction of c-Fos was monitored at the mRNA and protein levels. Similar results were obtained in two independent experiments. Significant differences were examined using the Student’s t-test, *P<0.05 compared with the culture with M-CSF.
Mentions: Finally, we examined the effect of inhibition of the MEK5/ERK5 pathway on the differentiation of M-BMMs into osteoclasts. M-BMMs were stimulated with M-CSF and sRANKL for 7 days to form TRAP (+) MNCs. MEK5 and ERK5 inhibitors blocked the formation of TRAP (+) MNCs, respectively (Fig 9A and 9B). These cells were more sensitive to the drugs than 4B12 or RAW264.6D clone cells. The viability of the cells was not affected by the drug treatment (Fig 9C). The induction of c-Fos was also examined. c-Fos expression induced by M-CSF was inhibited by treatment with the MEK5 and ERK5 pathway inhibitors (Fig 9D). These results suggest that M-CSF stimulation of the MEK5/ERK5 pathway is required for the formation of osteoclasts in primary M-BMM as well as in 4B12 or RAW264.7D clone cell cultures.

Bottom Line: Therefore, activation of ERK5 is required for the induction of c-Fos.These events were confirmed in experiments using M-CSF-dependent bone marrow macrophages.Taken together, the present results show that activation of the MEK5/ERK5 pathway with M-CSF is required for osteoclast differentiation, which may induce differentiation through the induction of c-Fos.

View Article: PubMed Central - PubMed

Affiliation: Division of Microbiology and Immunology, Department of Oral Biology and Tissue Engineering, Meikai University School of Dentistry, Keyakidai, Sakado City, Japan.

ABSTRACT
The MEK/ERK pathways are critical for controlling cell proliferation and differentiation. In this study, we show that the MEK5/ERK5 pathway participates in osteoclast differentiation. ERK5 was activated by M-CSF, which is one of the essential factors in osteoclast differentiation. Inhibition of MEK5 by BIX02189 or inhibition of ERK5 by XMD 8-92 blocked osteoclast differentiation. MEK5 knockdown inhibited osteoclast differentiation. RAW264.7D clone cells, which are monocytic cells, differentiate into osteoclasts after stimulation with sRANKL. ERK5 was activated without any stimulation in these cells. Inhibition of the MEK5/ERK5 pathway by the inhibitors also blocked the differentiation of RAW264.7D cells into osteoclasts. Moreover, expression of the transcription factor c-Fos, which is indispensable for osteoclast differentiation, was inhibited by treatment with MEK5 or ERK5 inhibitors. Therefore, activation of ERK5 is required for the induction of c-Fos. These events were confirmed in experiments using M-CSF-dependent bone marrow macrophages. Taken together, the present results show that activation of the MEK5/ERK5 pathway with M-CSF is required for osteoclast differentiation, which may induce differentiation through the induction of c-Fos.

No MeSH data available.


Related in: MedlinePlus