Mitochondrial and cytosolic thiol redox state are not detectably altered in isolated human NADH:ubiquinone oxidoreductase deficiency

Sjoerd Verkaart, Werner J.H. Koopman, Julia Cheek, Sjenet E. van Emst-de Vries, Lambertus W.P.J. van den Heuvel, Jan A.M. Smeitink*, Peter H.G.M. Willems

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

70 Citations (Scopus)

Abstract

Isolated complex I deficiency is the most common enzymatic defect of the oxidative phosphorylation (OXPHOS) system, causing a wide range of clinical phenotypes. We reported before that the rates at which reactive oxygen species (ROS)-sensitive dyes are converted into their fluorescent oxidation products are markedly increased in cultured skin fibroblasts of patients with nuclear-inherited isolated complex I deficiency. Using video-imaging microscopy we show here that these cells also display a marked increase in NAD(P)H autofluorescence. Linear regression analysis revealed a negative correlation with the residual complex I activity and a positive correlation with the oxidation rates of the ROS-sensitive dyes 5-(and-6)-chloromethyl-2′,7′-dichlorodihydrofluorescein and hydroethidine for a cohort of 10 patient cell lines. On the other hand, video-imaging microscopy of cells expressing reduction-oxidation sensitive GFP1 in either the mitochondrial matrix or cytosol showed the absence of any detectable change in thiol redox state. In agreement with this result, neither the glutathione nor the glutathione disulfide content differed significantly between patient and healthy fibroblasts. Finally, video-rate confocal microscopy of cells loaded with C11-BODIPY581/591 demonstrated that the extent of lipid peroxidation, which is regarded as a measure of oxidative damage, was not altered in patient fibroblasts. Our results indicate that fibroblasts of patients with isolated complex I deficiency maintain their thiol redox state despite marked increases in ROS production.

Original languageEnglish
Pages (from-to)1041-1051
Number of pages11
JournalBiochimica et Biophysica Acta - Molecular Basis of Disease
Volume1772
Issue number9
DOIs
Publication statusPublished - Sept 2007
Externally publishedYes

Keywords

  • Glutathione
  • Human skin fibroblasts
  • Lipid peroxidation
  • NADH:ubiquinone oxidoreductase
  • Reactive oxygen species
  • Redox environment
  • roGFP1
  • Superoxide
  • Thiol redox state

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