Brain monoamine oxidase B and A in human parkinsonian dopamine deficiency disorders
| Autor: | Lee-Cyn Ang, Oleh Hornykiewicz, Stephen J. Kish, Mark Guttman, Isabelle Boileau, Yoshiaki Furukawa, Junchao Tong, Gausiha Rathitharan, Jeffrey H. Meyer |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Male Dopamine 0302 clinical medicine Tubulin Putamen Brain Parkinson Disease Human brain Middle Aged Frontal Lobe Isoenzymes Substantia Nigra medicine.anatomical_structure alpha-Synuclein Female Monoamine oxidase B Supranuclear Palsy Progressive medicine.drug Adult medicine.medical_specialty Monoamine Oxidase Inhibitors Adolescent Monoamine oxidase Substantia nigra Progressive supranuclear palsy 03 medical and health sciences Young Adult Parkinsonian Disorders Internal medicine Glial Fibrillary Acidic Protein medicine Humans Monoamine Oxidase business.industry Original Articles Multiple System Atrophy medicine.disease Peptide Fragments 030104 developmental biology Monoamine neurotransmitter Endocrinology nervous system Case-Control Studies Phosphopyruvate Hydratase Nerve Degeneration Neurology (clinical) Caudate Nucleus business Neuroscience 030217 neurology & neurosurgery |
| Popis: | See Jellinger (doi:10.1093/awx190) for a scientific commentary on this article. The enzyme monoamine oxidases (B and A subtypes, encoded by MAOB and MAOA, respectively) are drug targets in the treatment of Parkinson’s disease. Inhibitors of MAOB are used clinically in Parkinson’s disease for symptomatic purposes whereas the potential disease-modifying effect of monoamine oxidase inhibitors is debated. As astroglial cells express high levels of MAOB, the enzyme has been proposed as a brain imaging marker of astrogliosis, a cellular process possibly involved in Parkinson’s disease pathogenesis as elevation of MAOB in astrocytes might be harmful. Since brain monoamine oxidase status in Parkinson’s disease is uncertain, our objective was to measure, by quantitative immunoblotting in autopsied brain homogenates, protein levels of both monoamine oxidases in three different degenerative parkinsonian disorders: Parkinson’s disease (n = 11), multiple system atrophy (n = 11), and progressive supranuclear palsy (n = 16) and in matched controls (n = 16). We hypothesized that if MAOB is ‘substantially’ localized to astroglial cells, MAOB levels should be generally associated with standard astroglial protein measures (e.g. glial fibrillary acidic protein). MAOB levels were increased in degenerating putamen (+83%) and substantia nigra (+10%, non-significant) in multiple system atrophy; in caudate (+26%), putamen (+27%), frontal cortex (+31%) and substantia nigra (+23%) of progressive supranuclear palsy; and in frontal cortex (+33%), but not in substantia nigra of Parkinson’s disease, a region we previously reported no increase in astrocyte protein markers. Although the magnitude of MAOB increase was less than those of standard astrocytic markers, significant positive correlations were observed amongst the astrocyte proteins and MAOB. Despite suggestions that MAOA (versus MAOB) is primarily responsible for metabolism of dopamine in dopamine neurons, there was no loss of the enzyme in the parkinsonian substantia nigra; instead, increased nigral levels of a MAOA fragment and ‘turnover’ of the enzyme were observed in the conditions. Our findings provide support that MAOB might serve as a biochemical imaging marker, albeit not entirely specific, for astrocyte activation in human brain. The observation that MAOB protein concentration is generally increased in degenerating brain areas in multiple system atrophy (especially putamen) and in progressive supranuclear palsy, but not in the nigra in Parkinson’s disease, also distinguishes astrocyte behaviour in Parkinson’s disease from that in the two ‘Parkinson-plus’ conditions. The question remains whether suppression of either MAOB in astrocytes or MAOA in dopamine neurons might influence progression of the parkinsonian disorders. |
| Databáze: | OpenAIRE |
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