DJ-1 null dopaminergic neuronal cells exhibit defects in mitochondrial function and structure: involvement of mitochondrial complex I assembly

• Published in: PloS one 2012-03, Vol.7 (3), p.e32629
• Main Authors: Heo, Jun Young, Park, Ji Hoon, Kim, Soung Jung, Seo, Kang Sik, Han, Jeong Su, Lee, Sang Hee, Kim, Jin Man, Park, Jong Il, Park, Seung Kiel, Lim, Kyu, Hwang, Byung Doo, Shong, Minho, Kweon, Gi Ryang
• Format: Article
• Language: English
• Subjects: Aberration; Abnormalities; Animals; Apoptosis; Assembly; Biochemistry; Biology; Confocal; Confocal microscopy; Cytotoxicity; Defects; Degeneration; Dopamine; Dopamine receptors; Dopaminergic Neurons - cytology; Dopaminergic Neurons - pathology; Electron microscopy; Electron transport; Electron transport chain; Electron Transport Complex I - chemistry; Electron Transport Complex I - deficiency; Electron Transport Complex I - metabolism; Fibroblasts; Gel electrophoresis; Gene Deletion; Gene Expression Regulation; Genes; Homeostasis; Humans; Internal medicine; Localization; Medicine; Membrane potential; Metabolic disorders; Mice; Mitochondria; Mitochondria - metabolism; Mitochondria - pathology; Mitochondrial Diseases - metabolism; Mitochondrial Diseases - pathology; Mitochondrial DNA; Movement disorders; Mutation; NADH-ubiquinone oxidoreductase; Neurodegeneration; Neurodegenerative diseases; Neurons; Null cells; Oncogene Proteins - deficiency; Oncogene Proteins - genetics; Oxygen; Oxygen consumption; PARK7 protein; Parkinson Disease - metabolism; Parkinson Disease - pathology; Parkinson's disease; Parkinsons disease; Pathogenesis; Peroxiredoxins; Protein Deglycase DJ-1; Proteins; Reactive oxygen species; Respiration; Rodents; Structure-function relationships; Studies; Thyroid gland; Two dimensional analysis
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0032629

DJ-1 is a Parkinson's disease-associated gene whose protein product has a protective role in cellular homeostasis by removing cytosolic reactive oxygen species and maintaining mitochondrial function. However, it is not clear how DJ-1 regulates mitochondrial function and why mitochondrial dysfunction is induced by DJ-1 deficiency. In a previous study we showed that DJ-1 null dopaminergic neuronal cells exhibit defective mitochondrial respiratory chain complex I activity. In the present article we investigated the role of DJ-1 in complex I formation by using blue native-polyacrylamide gel electrophoresis and 2-dimensional gel analysis to assess native complex status. On the basis of these experiments, we concluded that DJ-1 null cells have a defect in the assembly of complex I. Concomitant with abnormal complex I formation, DJ-1 null cells show defective supercomplex formation. It is known that aberrant formation of the supercomplex impairs the flow of electrons through the channels between respiratory chain complexes, resulting in mitochondrial dysfunction. We took two approaches to study these mitochondrial defects. The first approach assessed the structural defect by using both confocal microscopy with MitoTracker staining and electron microscopy. The second approach assessed the functional defect by measuring ATP production, O(2) consumption, and mitochondrial membrane potential. Finally, we showed that the assembly defect as well as the structural and functional abnormalities in DJ-1 null cells could be reversed by adenovirus-mediated overexpression of DJ-1, demonstrating the specificity of DJ-1 on these mitochondrial properties. These mitochondrial defects induced by DJ-1mutation may be a pathological mechanism for the degeneration of dopaminergic neurons in Parkinson's disease.