Enhanced ROS production and antioxidant defenses in cybrids harbouring mutations in mtDNA. Academic Article uri icon

Overview

abstract

  • It has been suggested that mutations in mitochondrial DNA (mtDNA) can produce an increase in reactive oxygen species (ROS) and that this can play a major role in the pathogenic mechanisms of mitochondrial encephalomyopathies. Many studies exist using electron transport chain (ETC) inhibitors, however there are only a few studies that examine ROS production associated with mutations in the mtDNA. To investigate this issue, we have studied ROS production, antioxidant defences and oxidative damage to lipids and proteins in transmitochondrial cybrids carrying different mtDNA mutations. Here, we report that two different mutant cell lines carrying mutations in their mitochondrial tRNA genes (A3243G in tRNA LeuUUR and A8344G in tRNA Lys) showed an increased ROS production with a parallel increase in the antioxidant enzyme activities, which may protect cells from oxidative damage in our experimental conditions (no overt oxidative damage to lipids and proteins has been observed). In contrast, cytochrome c oxidase (COX) mutant cybrids (carrying the stop-codon mutation G6930A in the COXI gene) showed neither an increase in ROS production nor elevation of antioxidant enzyme activities or oxidative damage. These results suggest that the specific location of mutations in mtDNA has a strong influence on the phenotype of the antioxidant response. Therefore, this issue should be carefully considered when antioxidant therapies are investigated in patients with mitochondrial disorders.

publication date

  • September 12, 2005

Research

keywords

  • Antioxidants
  • DNA, Mitochondrial
  • Lipid Metabolism
  • Osteosarcoma
  • Oxidative Stress
  • Reactive Oxygen Species

Identity

Scopus Document Identifier

  • 28444445608

PubMed ID

  • 16165271

Additional Document Info

volume

  • 391

issue

  • 3