AMP-activated protein kinase regulates thyroid hormone-stimulated osteocalcin synthesis in osteoblasts

  • Authors:
    • Akira Kondo
    • Takanobu Otsuka
    • Kenji Kato
    • Rie Matsushima-Nishiwaki
    • Gen Kuroyanagi
    • Jun Mizutani
    • Haruhiko Tokuda
    • Osamu Kozawa
  • View Affiliations

  • Published online on: April 15, 2013     https://doi.org/10.3892/ijmm.2013.1349
  • Pages: 1457-1462
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Abstract

AMP-activated protein kinase (AMPK) is recognized as a main regulator of energy homeostasis. Osteocalcin (OC), which is produced specifically by mature osteoblasts, is stored in bone matrix, strongly binds to hydroxyapatite and is released into the circulation, has been recognized as a marker of bone metabolism. It has recently been shown that OC released from osteoblasts influences energy metabolism as a hormone. We previously reported that triiodothyronine (T3) stimulates the synthesis of OC in osteoblast-like MC3T3-E1 cells. In the present study, we investigated whether AMPK participates in T3-stimulated OC synthesis in osteoblasts. T3 time-dependently induced the phosphorylation of the AMPKα-subunit (Thr-172), whereas T3 failed to induce the phosphorylation of AMPKα-subunit (Ser-485), AMPKβ-subunit (Ser-108) and AMPKβ-subunit (Ser-182). Both the release and the mRNA expression of OC induced by T3 were significantly inhibited by compound C, an AMPK inhibitor. Compound C suppressed the T3-induced phosphorylation of acetyl-CoA carboxylase, a direct substrate of AMPK. T3-stimulated OC release was significantly reduced in AMPK-knockdown cells using AMPK-siRNA. These results strongly suggest that AMPK positively regulates T3-stimulated OC synthesis in osteoblasts.
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June 2013
Volume 31 Issue 6

Print ISSN: 1107-3756
Online ISSN:1791-244X

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Spandidos Publications style
Kondo A, Otsuka T, Kato K, Matsushima-Nishiwaki R, Kuroyanagi G, Mizutani J, Tokuda H and Kozawa O: AMP-activated protein kinase regulates thyroid hormone-stimulated osteocalcin synthesis in osteoblasts. Int J Mol Med 31: 1457-1462, 2013
APA
Kondo, A., Otsuka, T., Kato, K., Matsushima-Nishiwaki, R., Kuroyanagi, G., Mizutani, J. ... Kozawa, O. (2013). AMP-activated protein kinase regulates thyroid hormone-stimulated osteocalcin synthesis in osteoblasts. International Journal of Molecular Medicine, 31, 1457-1462. https://doi.org/10.3892/ijmm.2013.1349
MLA
Kondo, A., Otsuka, T., Kato, K., Matsushima-Nishiwaki, R., Kuroyanagi, G., Mizutani, J., Tokuda, H., Kozawa, O."AMP-activated protein kinase regulates thyroid hormone-stimulated osteocalcin synthesis in osteoblasts". International Journal of Molecular Medicine 31.6 (2013): 1457-1462.
Chicago
Kondo, A., Otsuka, T., Kato, K., Matsushima-Nishiwaki, R., Kuroyanagi, G., Mizutani, J., Tokuda, H., Kozawa, O."AMP-activated protein kinase regulates thyroid hormone-stimulated osteocalcin synthesis in osteoblasts". International Journal of Molecular Medicine 31, no. 6 (2013): 1457-1462. https://doi.org/10.3892/ijmm.2013.1349