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Diabetes. 2014 Jun;63(6):1907-13. doi: 10.2337/db13-0816. Epub 2014 Feb 11.

High-fat diet-induced mitochondrial biogenesis is regulated by mitochondrial-derived reactive oxygen species activation of CaMKII.

Author information

  • 1Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.
  • 2Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada.
  • 3Department of Human Biology, Maastricht University, Maastricht, the Netherlands.
  • 4Department of Human Health & Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada ghollowa@uoguelph.ca.

Abstract

Calcium/calmodulin-dependent protein kinase (CaMK) activation induces mitochondrial biogenesis in response to increasing cytosolic calcium concentrations. Calcium leak from the ryanodine receptor (RyR) is regulated by reactive oxygen species (ROS), which is increased with high-fat feeding. We examined whether ROS-induced CaMKII-mediated signaling induced skeletal muscle mitochondrial biogenesis in selected models of lipid oversupply. In obese Zucker rats and high-fat-fed rodents, in which muscle mitochondrial content was upregulated, CaMKII phosphorylation was increased independent of changes in calcium uptake because sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) protein expression or activity was not altered, implicating altered sarcoplasmic reticulum (SR) calcium leak in the activation of CaMKII. In support of this, we found that high-fat feeding increased mitochondrial ROS emission and S-nitrosylation of the RyR, whereas hydrogen peroxide induced SR calcium leak from the RyR and activation of CaMKII. Moreover, administration of a mitochondrial-specific antioxidant, SkQ, prevented high-fat diet-induced phosphorylation of CaMKII and the induction of mitochondrial biogenesis. Altogether, these data suggest that increased mitochondrial ROS emission is required for the induction of SR calcium leak, activation of CaMKII, and induction of mitochondrial biogenesis in response to excess lipid availability.

© 2014 by the American Diabetes Association.

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