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BioMed Research International
Volume 2017, Article ID 7097580, 9 pages
https://doi.org/10.1155/2017/7097580
Research Article

Effects of Cobalt Chloride, a Hypoxia-Mimetic Agent, on Autophagy and Atrophy in Skeletal C2C12 Myotubes

1Guangdong Traditional Medical and Sports Injury Rehabilitation Research Institute, Guangdong No. 2 Provincial People’s Hospital, 466 Xin Gang Zhong Road, Guangzhou 510317, China
2Department of Radiology, The Third Affiliated Hospital, Sun Yat-sen University, 600 Tian He Road, Guangzhou 510630, China
3Department of Nuclear Medicine, The Third Affiliated Hospital, Sun Yat-sen University, 600 Tian He Road, Guangzhou 510630, China
4Department of Hematology, Guangdong No. 2 Provincial People’s Hospital, 466 Xin Gang Zhong Road, Guangzhou 510317, China

Correspondence should be addressed to Rui Chen; moc.361@dem.c.iur

Received 7 February 2017; Revised 15 May 2017; Accepted 24 May 2017; Published 19 June 2017

Academic Editor: Janusz Blasiak

Copyright © 2017 Rui Chen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background. Hypoxia-induced autophagy and muscle wasting occur in several environmental and pathological conditions. However, the molecular mechanisms underlying the effects of the hypoxia-mimetic agent CoCl2 on autophagy and muscle atrophy are still unclear. Methods. C2C12 myotubes were exposed to increasing concentrations of CoCl2 for 24 hours. Quantitative RT-PCR, Western blotting, and transmission electron microscopy were performed to confirm autophagy occurs. Autophagy proteins were measured to understand the molecule mechanisms. We also inhibited hypoxic autophagy and examined the changes in myogenin expression, myotubes formation, and apoptosis. Results. Our results showed that CoCl2-mimicked hypoxia upregulated the expression of the autophagy-related proteins LC3, HIF-1α, BNIP3, p-AMPKα, and beclin-1, whereas p62 and p-mTOR were downregulated. In addition, the autophagosome could be observed after CoCl2 induction. The expression of the autophagy-related E3 ligase parkin and the muscle-specific ubiquitin ligase atrogin-1 was increased by CoCl2. Inhibition of autophagy by 3MA increased myogenin expression and promoted myotubes formation and the percentage of cell death was decreased. Conclusions. Our results confirmed that CoCl2-mimicked hypoxia induced autophagy via the HIF-1α/BNIP3/beclin-1 and AMPK/mTOR pathways. Our results also revealed an important link between autophagy and muscle atrophy under hypoxia, which may help to develop new therapeutic strategies for muscle diseases.