Open Access

Strontium promotes osteogenic differentiation by activating autophagy via the the AMPK/mTOR signaling pathway in MC3T3‑E1 cells

  • Authors:
    • You Cheng
    • Lunhui Huang
    • Yichao Wang
    • Qianyu Huo
    • Yanhong Shao
    • Huijing Bao
    • Zhaoyang Li
    • Yunde Liu
    • Xue Li
  • View Affiliations

  • Published online on: May 30, 2019     https://doi.org/10.3892/ijmm.2019.4216
  • Pages: 652-660
  • Copyright: © Cheng et al. This is an open access article distributed under the terms of Creative Commons Attribution License.

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Abstract

Strontium (Sr) is an alkaline earth metal that exerts the dual effect of improving bone formation and suppressing bone resorption, resulting in increased bone apposition rates and bone mineral density. However, the mechanisms through which Sr exerts these beneficial effects on bone have yet to be fully elucidated. The present study aimed to reveal the underlying molecular mechanisms associated with Sr‑induced osteogenic differentiation. The effects of Sr on cell proliferation and osteogenic differentiation were analyzed by MTT assay, RT‑qPCR, western blot analysis, alkaline phosphatase (ALP) and Alizarin red staining assays. The extent of autophagy was determined by monodansylcadaverine (MDC) staining and western blot analysis of two markers of cellular autophagic activity, the steatosis‑associated protein, sequestosome‑1 (SQSTM1/p62), and the two isoforms of microtubule‑associated protein 1 light chain 3 (LC3), LC‑3‑I/II. The expression levels of AMP‑activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR) were also detected by western blot analysis. Sr at a concentration of 3 mM exerted the most pronounced effect on osteogenic differentiation, without any apparent cell toxicity. At the same time, cellular autophagy was active during this process. Subsequently, autophagy was blocked by 3‑methyladenine, and the enhancement of osteogenic differentiation in response to Sr was abrogated. Additionally, the phosphorylation level of AMPK was significantly increased, whereas that of mTOR was significantly decreased, in the Sr‑treated group. Taken together, the findings of the present study demonstrate that Sr stimulates AMPK‑activated autophagy to induce the osteogenic differentiation of MC3T3‑E1 cells.
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August-2019
Volume 44 Issue 2

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

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Spandidos Publications style
Cheng Y, Huang L, Wang Y, Huo Q, Shao Y, Bao H, Li Z, Liu Y and Li X: Strontium promotes osteogenic differentiation by activating autophagy via the the AMPK/mTOR signaling pathway in MC3T3‑E1 cells. Int J Mol Med 44: 652-660, 2019.
APA
Cheng, Y., Huang, L., Wang, Y., Huo, Q., Shao, Y., Bao, H. ... Li, X. (2019). Strontium promotes osteogenic differentiation by activating autophagy via the the AMPK/mTOR signaling pathway in MC3T3‑E1 cells. International Journal of Molecular Medicine, 44, 652-660. https://doi.org/10.3892/ijmm.2019.4216
MLA
Cheng, Y., Huang, L., Wang, Y., Huo, Q., Shao, Y., Bao, H., Li, Z., Liu, Y., Li, X."Strontium promotes osteogenic differentiation by activating autophagy via the the AMPK/mTOR signaling pathway in MC3T3‑E1 cells". International Journal of Molecular Medicine 44.2 (2019): 652-660.
Chicago
Cheng, Y., Huang, L., Wang, Y., Huo, Q., Shao, Y., Bao, H., Li, Z., Liu, Y., Li, X."Strontium promotes osteogenic differentiation by activating autophagy via the the AMPK/mTOR signaling pathway in MC3T3‑E1 cells". International Journal of Molecular Medicine 44, no. 2 (2019): 652-660. https://doi.org/10.3892/ijmm.2019.4216