Journal Article

The mtDNA T8993G (NARP) mutation results in an impairment of oxidative phosphorylation that can be improved by antioxidants

Marina Mattiazzi, Chetan Vijayvergiya, Carl D. Gajewski, Darryl C. DeVivo, Giorgio Lenaz, Martin Wiedmann and Giovanni Manfredi

in Human Molecular Genetics

Volume 13, issue 8, pages 869-879
Published in print April 2004 | ISSN: 0964-6906
Published online March 2004 | e-ISSN: 1460-2083 | DOI: http://dx.doi.org/10.1093/hmg/ddh103
The mtDNA T8993G (NARP) mutation results in an impairment of oxidative phosphorylation that can be improved by antioxidants

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A T8993G point mutation in the mtDNA results in a Leu156Arg substitution in the MTATP6 subunit of the mitochondrial F1F0-ATPase. The T8993G mutation causes impaired oxidative phosphorylation (OXPHOS) in two mitochondrial disorders, NARP (neuropathy, ataxia and retinitis pigmentosa) and MILS (maternally inherited Leigh's syndrome). It has been reported, in some studies, that the T8993G mutation results in loss of assembled F1F0-ATPase. Others reported that the mutation causes impairment of proton flow through F0. In addition, it was shown that fibroblasts from NARP subjects have a tendency to undergo apoptotic cell death, perhaps as a result of increased free radical production. Here, we show that the T8993G mutation inhibits oxidative phosphorylation and results in enhanced free radical production. We suggest that free radical-mediated inhibition of OXPHOS contributes to the loss of ATP synthesis. Importantly, we show that antioxidants restore respiration and partially rescue ATP synthesis in cells harboring the T8993G mutation. Our results indicate that free radicals might play an important role in the pathogenesis of NARP/MILS and that this can be prevented by antioxidants. The effectiveness of antioxidant agents in cultured NARP/MILS cells suggests that they might have a potential beneficial role in the treatment of patients with NARP.

Journal Article.  7523 words.  Illustrated.

Subjects: Genetics and Genomics

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