title: Recovery of MERRF fibroblasts and cybrids pathophysiology by coenzyme Q10.
abstract: Mitochondrial DNA mutations are an important cause of human disease for which there is no effective treatment. Myoclonic epilepsy with ragged-red fibers (MERRF) is a mitochondrial disease usually caused by point mutations in transfer RNA genes encoded by mitochondrial DNA. The most common mutation associated with MERRF syndrome, m.8344A > G in the gene MT-TK, which encodes transfer RNA(Lysine), affects the translation of all mitochondrial DNA encoded proteins. This impairs the assembly of the electron transport chain complexes leading to decreased mitochondrial respiratory function. Here we report on how this mutation affects mitochondrial function in primary fibroblast cultures established from patients harboring the A8344G mutation. Coenzyme Q10 levels, as well as mitochondrial respiratory chain activity, and mitochondrial protein expression levels were significantly decreased in MERRF fibroblasts. Mitotracker staining and imaging analysis of individual mitochondria indicated the presence of small, rounded, depolarized mitochondria in MERRF fibroblasts. Mitochondrial dysfunction was associated with increased oxidative stress and increased degradation of impaired mitochondria by mitophagy. Transmitochondrial cybrids harboring the A8344G mutation also showed CoQ10 deficiency, mitochondrial dysfunction, and increased mitophagy activity. All these abnormalities in patient-derived fibroblasts and cybrids were partially restored by CoQ10 supplementation, indicating that these cell culture models may be suitable for screening and validation of novel drug candidates for MERRF disease.
authors.affiliation: Centro Andaluz de Biología del Desarrollo, CABD-CSIC-UPO-JA and Centro de Investigación Biomédica en Red: Enfermedades Raras-CIBERER, Instituto de Salud Carlos III, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas-Junta de Andalucía, Sevilla 41013, Spain.
authors.forename: Mario
authors.initials: M
authors.lastname: De la Mata
authors.forename: Juan
authors.initials: J
authors.lastname: Garrido-Maraver
authors.forename: David
authors.initials: D
authors.lastname: Cotán
authors.forename: Mario D
authors.initials: MD
authors.lastname: Cordero
authors.forename: Manuel
authors.initials: M
authors.lastname: Oropesa-Ávila
authors.forename: Lourdes Gómez
authors.initials: LG
authors.lastname: Izquierdo
authors.forename: Manuel
authors.initials: M
authors.lastname: De Miguel
authors.forename: Juan Bautista
authors.initials: JB
authors.lastname: Lorite
authors.forename: Eloy Rivas
authors.initials: ER
authors.lastname: Infante
authors.forename: Patricia
authors.initials: P
authors.lastname: Ybot
authors.forename: Sandra
authors.initials: S
authors.lastname: Jackson
authors.forename: José A
authors.initials: JA
authors.lastname: Sánchez-Alcázar
mesh_terms: D002460:Cell Line; D002478:Cells, Cultured; D005347:Fibroblasts / Q000473:pathology* / Q000502:physiology; D006801:Humans; D017243:MERRF Syndrome / Q000235:genetics / Q000473:pathology* / Q000503:physiopathology*; D053078:Membrane Potential, Mitochondrial / Q000235:genetics; D009154:Mutation / Q000235:genetics; D014451:Ubiquinone / Q000031:analogs & derivatives* / Q000502:physiology
chemical_list: D014451:Ubiquinone; C024989:coenzyme Q10