Combination treatment with antioxidants and creatine alleviates common and variant-specific mitochondrial impairments in Leber's hereditary optic neuropathy patient-derived fibroblasts.

Abstract

Leber's hereditary optic neuropathy (LHON) is characterized by painless and rapidly progressive central vision loss, caused by various mutations in mitochondrial DNA, leading to a high genetic and phenotypic heterogeneity. Currently, the only approved therapy is idebenone, a CoQ10 synthetic analogue, that improved visual acuity in some LHON patients; however, results are highly variable due its dependency on functional NAD(P)H oxidoreductase I (NQO1) protein levels, thus limiting broader applicability. Targeting the biochemical respiratory chain defect and mitigating reactive oxygen species emission using alternative treatments which act independent of NQO1 protein content, represent a promising therapeutic strategy for all LHON patients. Here, we first characterized mitochondrial biology of three distinct LHON mutations in patient-derived fibroblasts and evaluated the effects of a nutraceutical combination treatment in addressing these shared pathophysiological mechanisms. We identified a range of mitochondrial characteristics common among various LHON mutations, including higher ROS levels, altered autophagy programming, and reduced mitochondrial bioenergetics. Repeated antioxidant and creatine-based treatment (ACT) conferred a favorable stress-resistant phenotype in LHON cells, which was similar to, and in some cases superior to, the effects observed with idebenone treatment, irrespective of NQO1 protein expression. This phenotype was associated with enhanced mitochondrial biology, as evidenced by reduced reactive oxygen species levels, increased cellular respiration, and correction of autophagic flux. Overall, our findings reveal both common and divergent mitochondrial phenotypes among LHON-related mutations and highlight the potential of accessible multi-ingredient nutraceutical interventions that could benefit all LHON patients.