Arabidopsis thaliana alternative dehydrogenases: a potential therapy for mitochondrial complex I deficiency? Perspectives and pitfalls

Orphanet J Rare Dis. 2019 Oct 29;14(1):236. doi: 10.1186/s13023-019-1185-3.


Background: Complex I (CI or NADH:ubiquinone oxidoreductase) deficiency is the most frequent cause of mitochondrial respiratory chain defect. Successful attempts to rescue CI function by introducing an exogenous NADH dehydrogenase, such as the NDI1 from Saccharomyces cerevisiae (ScNDI1), have been reported although with drawbacks related to competition with CI. In contrast to ScNDI1, which is permanently active in yeast naturally devoid of CI, plant alternative NADH dehydrogenases (NDH-2) support the oxidation of NADH only when the CI is metabolically inactive and conceivably when the concentration of matrix NADH exceeds a certain threshold. We therefore explored the feasibility of CI rescue by NDH-2 from Arabidopsis thaliana (At) in human CI defective fibroblasts.

Results: We showed that, other than ScNDI1, two different NDH-2 (AtNDA2 and AtNDB4) targeted to the mitochondria were able to rescue CI deficiency and decrease oxidative stress as indicated by a normalization of SOD activity in human CI-defective fibroblasts. We further demonstrated that when expressed in human control fibroblasts, AtNDA2 shows an affinity for NADH oxidation similar to that of CI, thus competing with CI for the oxidation of NADH as opposed to our initial hypothesis. This competition reduced the amount of ATP produced per oxygen atom reduced to water by half in control cells.

Conclusions: In conclusion, despite their promising potential to rescue CI defects, due to a possible competition with remaining CI activity, plant NDH-2 should be regarded with caution as potential therapeutic tools for human mitochondrial diseases.

Keywords: Alternative dehydrogenases; Arabidopsis thaliana; AtNDA2; Complex I; Mitochondria; Mitochondrial diseases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / enzymology*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Cells, Cultured
  • Electron Transport Complex I / deficiency*
  • Electron Transport Complex I / genetics
  • Electron Transport Complex I / metabolism
  • Fibroblasts / metabolism*
  • Humans
  • Mitochondrial Diseases / drug therapy*
  • NADH, NADPH Oxidoreductases / genetics
  • NADH, NADPH Oxidoreductases / metabolism*
  • NADPH Dehydrogenase / genetics
  • NADPH Dehydrogenase / metabolism*
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Superoxide Dismutase
  • Transfection


  • Arabidopsis Proteins
  • Ndi1 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Superoxide Dismutase
  • NADH, NADPH Oxidoreductases
  • NDA2 protein, Arabidopsis
  • AT2G20800 protein, Arabidopsis
  • NADPH Dehydrogenase
  • Electron Transport Complex I
  • NDUFS4 protein, human

Supplementary concepts

  • Mitochondrial complex I deficiency