Bulk autophagy, but not mitophagy, is increased in cellular model of mitochondrial disease

BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR BASIS OF DISEASE

卷:1842

Article

Moran, Maria^1,2  Delmiro, Aitor^1,2  Blazquez, Alberto^1,2  Ugalde, Cristina^1,2  Arenas, Joaquin¹  Martin, Miguel A.^1,2 

[1] Inst Invest Hosp Univ 12 Octubre i 12, Ctr Actividades Ambulatorias, Lab Enfermedades Raras Mitocondri Neuromuscul, Madrid 28041, Spain

[2] CIBERER, Spanish Network Biomed Res Rare Dis, U723, Madrid, Spain

关键词: Autophagy;    OXPHOS deficiency;    Parkin;    Autophagosome;    Mitophagy;    Lysosome;   

DOI  :  10.1016/j.bbadis.2014.03.013

来源: Elsevier

【 摘 要 】

Oxidative phosphorylation system (OXPHOS) deficiencies are rare diseases but constitute the most frequent inborn errors of metabolism. We analyzed the autophagy route in 11 skin fibroblast cultures derived from patients with well characterized and distinct OXPHOS defects. Mitochondrial membrane potential determination revealed a tendency to decrease in 5 patients' cells but reached statistical significance only in 2 of them. The remaining cells showed either no change or a slight increase in this parameter. Colocalization analysis of mitochondria and autophagosomes failed to show evidence of increased selective elimination of mitochondria but revealed more intense autophagosome staining in patients' fibroblasts compared with controls. Despite the absence of increased mitophagy, Parkin recruitment to mitochondria was detected in both controls' and patients' cells and was slightly higher in cells harboring complex I defects. Western blot analysis of the autophagosome marker LOB, confirmed significantly higher levels of the protein bound to autophagosomes, LOB-II, in patients' cells, suggesting an increased bunt autophagy in OXPHOS defective fibroblasts. Inhibition of lysosomal proteases caused significant accumulation of LOB-II in control cells, whereas in patients' cells this phenomenon was less pronounced. Electron microscopy studies showed higher content of late autophagic vacuoles and lysosomes in OXPHOS defective cells, accompanied by higher levels of the lysosomal marker LAMP-1. Our findings suggest that in OXPHOS deficient fibroblasts autophagic flux could be partially hampered leading to an accumulation of autophagic vacuoles and lysosomes. (C) 2014 Elsevier B.V. All rights reserved.

【 授权许可】

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