N-myc and c-myc expression in Alzheimer disease, Huntington disease and Parkinson disease.
The present study examines N-myc and c-myc protein expression with Western blotting and single and double-labeling immunohistochemistry in the hippocampus in Alzheimer disease (AD), the striatum in Huntington disease (HD) and the substantia nigra in Parkinson disease (PD). No modifications in the N-myc and c-myc expression are found in hippocampal neurons in AD, striatal neurons in HD, and pigmented neurons of the substantia nigra in PD. Yet punctate synaptic-like N-myc immunoreactivity, matching enhanced synaptophysin expression, occurs in diffuse plaques, but not in dystrophic neurites of neuritic plaques. In contrast, c-myc immunoreactivity is found in dystrophic neurites, but not in aberrant sproutings of neuritic plaques, as shown by double-labeling immunohistochemistry to c-myc and phosphorylated tau or phosphorylated neurofilament epitopes, and to c-myc and GAP-43, respectively. Strong N-myc and c-myc are observed in reactive astrocytes in AD, HD and PD, as revealed by double-labeling with N-myc or c-myc and GFAP. Finally, no relationship is found between nuclear DNA fragmentation and increased N-myc or c-myc expression in individual cells. These results demonstrate that neuron death in AD, HD and PD is not associated with modifications in the steady-state expression of N-myc and c-myc in individual neurons, and that neurofibrillary degeneration and Lewy body formation are not accompanied by increased immunoreactivity to these transcription factors. Increased N-myc and c-myc expression in reactive astrocytes probably plays a role in reactive astrocytosis in human neurodegenerative disorders.
Ferrer
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I
Unitat de Neuropatologia, Servei d'Anatomia Patològica, Hospital Princeps d'Espanya, i Departament de Biologia Cel.lular i Anatomia Patològica, Facultat de Medicina, Universitat de Barcelona, Hospitalet de Llobregat, Llobregat, Spain. iferrer@sakma.es
Blanco
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R
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000378:metabolism* / Q000473:pathology; D001253:Astrocytes / Q000378:metabolism / Q000473:pathology; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism* / Q000473:pathology*; D016923:Cell Death; D053938:DNA Fragmentation; D005260:Female; D005911:Gliosis / Q000378:metabolism / Q000473:pathology; D006624:Hippocampus / Q000378:metabolism / Q000473:pathology; D006801:Humans; D006816:Huntington Disease / Q000378:metabolism* / Q000473:pathology; D007150:Immunohistochemistry; D008297:Male; D017072:Neostriatum / Q000378:metabolism / Q000473:pathology; D010300:Parkinson Disease / Q000378:metabolism* / Q000473:pathology; D058225:Plaque, Amyloid / Q000378:metabolism / Q000473:pathology; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism*; D013378:Substantia Nigra / Q000378:metabolism / Q000473:pathology
D016271:Proto-Oncogene Proteins c-myc