Cytoprotective Role of Nrf2 in Electrical Pulse Stimulated C2C12 Myotube

PLoS One. 2015 Dec 14;10(12):e0144835. doi: 10.1371/journal.pone.0144835. eCollection 2015.

Abstract

Regular physical exercise is central to a healthy lifestyle. However, exercise-related muscle contraction can induce reactive oxygen species and reactive nitrogen species (ROS/RNS) production in skeletal muscle. The nuclear factor-E2-related factor-2 (Nrf2) transcription factor is a cellular sensor for oxidative stress. Regulation of nuclear Nrf2 signaling regulates antioxidant responses and protects organ structure and function. However, the role of Nrf2 in exercise- or contraction-induced ROS/RNS production in skeletal muscle is not clear. In this study, using differentiated C2C12 cells and electrical pulse stimulation (EPS) of muscle contraction, we explored whether Nrf2 plays a role in the skeletal muscle response to muscle contraction-induced ROS/RNS. We found that EPS (40 V, 1 Hz, 2 ms) stimulated ROS/RNS accumulation and Nrf2 activation. We also showed that expression of NQO1, HO-1 and GCLM increased after EPS-induced muscle contraction and was remarkably suppressed in cells with Nrf2 knockdown. We also found that the antioxidant N-acetylcysteine (NAC) significantly attenuated Nrf2 activation after EPS, whereas the nitric oxide synthetase inhibitor Nω-nitro-L-arginine methyl ester (L-NAME) did not. Furthermore, Nrf2 knockdown after EPS markedly decreased ROS/RNS redox potential and cell viability and increased expression of the apoptosis marker Annexin V in C2C12 myotubes. These results indicate that Nrf2 activation and expression of Nrf2 regulated-genes protected muscle against the increased ROS caused by EPS-induced muscle contraction. Thus, our findings suggest that Nrf2 may be a key factor for preservation of muscle function during muscle contraction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antioxidants / metabolism
  • Apoptosis / physiology
  • Cell Line
  • Cell Survival / physiology
  • Cytoprotection
  • Electric Stimulation
  • Mice
  • Muscle Fibers, Skeletal / metabolism
  • Muscle, Skeletal / cytology
  • Muscle, Skeletal / metabolism*
  • NF-E2-Related Factor 2 / metabolism*
  • Oxidative Stress / physiology
  • Reactive Nitrogen Species / metabolism
  • Reactive Oxygen Species / metabolism
  • Signal Transduction

Substances

  • Antioxidants
  • NF-E2-Related Factor 2
  • Nfe2l2 protein, mouse
  • Reactive Nitrogen Species
  • Reactive Oxygen Species

Grants and funding

This work was, in part, supported by the Japan Health Science Foundation and a Grant-in-Aid for Scientific Research on Priority Areas, Ministry of Education, Science and culture, Japan (Research project number: 13J00516), MH.