Potentially diagnostic electron paramagnetic resonance spectra elucidate the underlying mechanism of mitochondrial dysfunction in the deoxyguanosine kinase deficient rat model of a genetic mitochondrial DNA depletion syndrome

Free Radic Biol Med. 2016 Mar:92:141-151. doi: 10.1016/j.freeradbiomed.2016.01.001. Epub 2016 Jan 8.

Abstract

A novel rat model for a well-characterized human mitochondrial disease, mitochondrial DNA depletion syndrome with associated deoxyguanosine kinase (DGUOK) deficiency, is described. The rat model recapitulates the pathologic and biochemical signatures of the human disease. The application of electron paramagnetic (spin) resonance (EPR) spectroscopy to the identification and characterization of respiratory chain abnormalities in the mitochondria from freshly frozen tissue of the mitochondrial disease model rat is introduced. EPR is shown to be a sensitive technique for detecting mitochondrial functional abnormalities in situ and, here, is particularly useful in characterizing the redox state changes and oxidative stress that can result from depressed expression and/or diminished specific activity of the distinct respiratory chain complexes. As EPR requires no sample preparation or non-physiological reagents, it provides information on the status of the mitochondrion as it was in the functioning state. On its own, this information is of use in identifying respiratory chain dysfunction; in conjunction with other techniques, the information from EPR shows how the respiratory chain is affected at the molecular level by the dysfunction. It is proposed that EPR has a role in mechanistic pathophysiological studies of mitochondrial disease and could be used to study the impact of new treatment modalities or as an additional diagnostic tool.

Keywords: DGUOK; EPR; ESR; Oxidative; Pathology; Redox; Stress; mtDNA depletion.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • DNA, Mitochondrial / genetics
  • Disease Models, Animal
  • Electron Spin Resonance Spectroscopy*
  • Electron Transport / genetics
  • Humans
  • Intestinal Pseudo-Obstruction / diagnosis*
  • Intestinal Pseudo-Obstruction / metabolism
  • Intestinal Pseudo-Obstruction / pathology
  • Mitochondria / metabolism
  • Mitochondria / pathology*
  • Mitochondrial Diseases / diagnosis*
  • Mitochondrial Diseases / genetics
  • Mitochondrial Diseases / metabolism
  • Mitochondrial Diseases / pathology
  • Mitochondrial Encephalomyopathies / diagnosis*
  • Mitochondrial Encephalomyopathies / metabolism
  • Mitochondrial Encephalomyopathies / pathology
  • Muscular Dystrophy, Oculopharyngeal
  • Ophthalmoplegia / congenital
  • Oxidation-Reduction
  • Oxidative Stress / genetics
  • Phosphotransferases (Alcohol Group Acceptor) / genetics*
  • Phosphotransferases (Alcohol Group Acceptor) / isolation & purification
  • Phosphotransferases (Alcohol Group Acceptor) / metabolism
  • Rats

Substances

  • DNA, Mitochondrial
  • Phosphotransferases (Alcohol Group Acceptor)
  • deoxyguanosine kinase

Supplementary concepts

  • Deoxyguanosine Kinase Deficiency
  • Visceral myopathy familial external ophthalmoplegia