Elevated mitochondrial oxidative stress impairs metabolic adaptations to exercise in skeletal muscle

PLoS One. 2013 Dec 6;8(12):e81879. doi: 10.1371/journal.pone.0081879. eCollection 2013.

Abstract

Mitochondrial oxidative stress is a complex phenomenon that is inherently tied to energy provision and is implicated in many metabolic disorders. Exercise training increases mitochondrial oxidative capacity in skeletal muscle yet it remains unclear if oxidative stress plays a role in regulating these adaptations. We demonstrate that the chronic elevation in mitochondrial oxidative stress present in Sod2 (+/-) mice impairs the functional and biochemical mitochondrial adaptations to exercise. Following exercise training Sod2 (+/-) mice fail to increase maximal work capacity, mitochondrial enzyme activity and mtDNA copy number, despite a normal augmentation of mitochondrial proteins. Additionally, exercised Sod2 (+/-) mice cannot compensate for their higher amount of basal mitochondrial oxidative damage and exhibit poor electron transport chain complex assembly that accounts for their compromised adaptation. Overall, these results demonstrate that chronic skeletal muscle mitochondrial oxidative stress does not impact exercise induced mitochondrial biogenesis, but impairs the resulting mitochondrial protein function and can limit metabolic plasticity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological*
  • Animals
  • DNA, Mitochondrial / genetics
  • DNA, Mitochondrial / metabolism
  • DNA-Binding Proteins
  • Electron Transport
  • High Mobility Group Proteins
  • Mice
  • Mitochondria / metabolism*
  • Mitochondrial Proteins / metabolism
  • Muscle, Skeletal / pathology*
  • Muscle, Skeletal / physiopathology*
  • Oxidation-Reduction
  • Oxidative Stress*
  • Physical Conditioning, Animal*
  • Protein Folding
  • Superoxide Dismutase / metabolism
  • Transcription, Genetic

Substances

  • DNA, Mitochondrial
  • DNA-Binding Proteins
  • High Mobility Group Proteins
  • Mitochondrial Proteins
  • Tfam protein, mouse
  • Superoxide Dismutase

Grant support

This work was supported by a grant from the National Sciences and Engineering Research Council (NSERC) of Canada to M. Tarnopolsky. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.