Author(s): Qi X, Sun L, Hauswirth WW, Lewin AS, Guy J
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Abstract OBJECTIVE: To explore a treatment paradigm for Leber hereditary optic neuropathy (LHON), we augmented mitochondrial antioxidant defenses to rescue cells with the G11778A mutation in mitochondrial DNA. METHODS: Cells homoplasmic for the G11778A mutation in mitochondrial DNA were infected with an adeno-associated viral vector containing the human mitochondrial superoxide dismutase (SOD2) gene. Control cells were infected with an adeno-associated viral (AAV) vector expressing the green fluorescent protein (GFP). Two days later, the high-glucose culture medium was exchanged for a glucose-free medium containing galactose. After 1 or 2 days, cellular production of superoxide was assessed using the fluorescent probe dihydroethidium, and we used TUNEL (terminal deoxynucleotidyl transferase-mediated biotin-deoxyuridine triphosphate nick-end labeling) staining to detect apoptotic nuclei. The effect of SOD2 on LHON cell survival was quantitated after 2 or 3 days. RESULTS: Comparisons of AAV-SOD2-infected LHON cells relative to control cells infected with AAV-green fluorescent protein showed increased expression of mitochondrial SOD that attenuated superoxide-induced fluorescence by 26\% (P = .003) and suppressed TUNEL-induced fluorescence by 21\% (P = .048) after 2 days of growth in galactose medium, when cell survival increased by 25\% (P=.05). After 3 days in galactose medium, SOD2 increased LHON survival by 89\% (P = .006) relative to controls. CONCLUSION: Protection against mitochondrial oxidative stress may be useful for treatment of LHON. CLINICAL RELEVANCE: Gene therapy with antioxidant genes may protect patients with LHON against visual loss.
This article was published in Arch Ophthalmol
and referenced in Journal of Genetic Syndromes & Gene Therapy