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Closed Access item Secondary coenzyme Q10 deficiency triggers mitochondria degradation by mitophagy in MELAS fibroblasts

Authors:Cotán, David
Cordero, Mario D.
Garrido-Maraver, Juan
Oropesa-Ávila, Manuel
Rodríguez-Hernández, Ángeles
Gómez Izquierdo, Lourdes
Mata, Mario de la
Miguel, Manuel de
Bautista Lorite, Juan
Rivas Infante, Eloy
Jackson, Sandra
Navas, Plácido
Sánchez-Alcázar, José Antonio
Keywords:Autophagy, Free radicals, Mitochondrial diseases, Electron transport, Fibroblasts, MELAS syndrome, Microtubule-associated proteins, Ubiquinone
Issue Date:6-May-2011
Publisher:Federation of American Societies for Experimental Biology
Citation:FASEB Journal - Federation of American Societies for Experimental Biology 25(8): 2669-2687 (2011)
Abstract:Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) is a mitochondrial disease most usually caused by point mutations in tRNA genes encoded by mtDNA. Here, we report on how this mutation affects mitochondrial function in primary fibroblast cultures established from 2 patients with MELAS who harbored the A3243G mutation. Both mitochondrial respiratory chain enzyme activities and coenzyme Q(10) (CoQ) levels were significantly decreased in MELAS fibroblasts. A similar decrease in mitochondrial membrane potential was found in intact MELAS fibroblasts. Mitochondrial dysfunction was associated with increased oxidative stress and the activation of mitochondrial permeability transition (MPT), which triggered the degradation of impaired mitochondria. Furthermore, we found defective autophagosome elimination in MELAS fibroblasts. Electron and fluorescence microscopy studies confirmed a massive degradation of mitochondria and accumulation of autophagosomes, suggesting mitophagy activation and deficient autophagic flux. Transmitochondrial cybrids harboring the A3243G mutation also showed CoQ deficiency and increased autophagy activity. All these abnormalities were partially restored by CoQ supplementation. Autophagy in MELAS fibroblasts was also abolished by treatment with antioxidants or cyclosporine, suggesting that both reactive oxygen species and MPT participate in this process. Furthermore, prevention of autophagy in MELAS fibroblasts resulted in apoptotic cell death, suggesting a protective role of autophagy in MELAS fibroblasts.
Description:9 páginas.
Publisher version (URL):http://dx.doi.org/10.1096/fj.10-165340
URI:http://hdl.handle.net/10261/41221
ISSN:0892-6638
E-ISSNmetadata.dc.identifier.doi = DOI:1530-6860
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Appears in Collections:(CABD) Artículos

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