Decreased Brain Protein Levels of Cytochrome Oxidase Subunits in Alzheimer's Disease and in Hereditary Spinocerebella Ataxia Disorders
| Autor: | Slobodan Dozic, Linda DiStefano, Jacques Lamarche, Yoshiaki Furukawa, Jan-Willem Taanman, Massimo Pandolfo, Mark Guttman, Frank Mastrogiacomo, Li-Jan Chang, Stephen J. Kish |
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| Rok vydání: | 1999 |
| Předmět: |
medicine.medical_specialty
Ataxia Protein subunit Immunoblotting Citrate (si)-Synthase Biology Biochemistry Oxidative Phosphorylation Electron Transport Complex IV Cellular and Molecular Neuroscience Alzheimer Disease Cerebellum Internal medicine medicine Humans Cytochrome c oxidase Aged Cerebral Cortex Neurodegeneration Human brain medicine.disease Temporal Lobe Frontal Lobe Mitochondria medicine.anatomical_structure Endocrinology Friedreich Ataxia Cerebral cortex Cerebellar cortex Spinocerebellar ataxia biology.protein Regression Analysis Occipital Lobe medicine.symptom |
| Zdroj: | Journal of Neurochemistry. 72:700-707 |
| ISSN: | 0022-3042 |
| Popis: | Controversy exists as to the clinical importance, cause, and disease specificity of the cytochrome oxidase (CO) activity reduction observed in some patients with Alzheimer's disease (AD). Although it is assumed that the enzyme is present in normal amount in AD, no direct measurements of specific CO protein subunits have been conducted. We measured protein levels of CO subunits encoded by mitochondrial (COX I, COX II) and nuclear (COX IV, COX VIc) DNA in autopsied brain of patients with AD whom we previously reported had decreased cerebral cortical CO activity. To assess disease specificity, groups of patients with spinocerebellar ataxia type I and Friedreich's ataxia were also included. As compared with the controls, mean protein concentrations of all four CO subunits were significantly decreased (-19 to -47%) in temporal and parietal cortices in the AD group but were not significantly reduced (-12 to -17%) in occipital cortex. The magnitude of the reduction in protein levels of the CO subunits encoded by mitochondrial DNA (-42 to -47%) generally exceeded that encoded by nuclear DNA (-19 to -43%). In the spinocerebellar ataxia disorders, COX I and COX II levels were significantly decreased in cerebellar cortex (-22 to -32%) but were normal or close to normal in cerebral cortex, an area relatively unaffected by neurodegeneration. We conclude that protein levels of mitochondrial- and nuclear-encoded CO subunits are moderately reduced in degenerating but not in relatively spared brain areas in AD and that the decrease is not specific to this disorder. The simplest explanation for our findings is that CO is decreased in human brain disorders as a secondary event in brain areas having reduced neuronal activity or neuronal/synaptic elements consequent to the primary neurodegenerative process. |
| Databáze: | OpenAIRE |
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