The Lewy body in Parkinson's disease: Molecules implicated in the formation and degradation of α-synuclein aggregates

Authors


Koichi Wakabayashi, md, Department of Neuropathology, Institute of Brain Science, Hirosaki University School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Japan. Email: koichi@cc.hirosaki-u.ac.jp

Abstract

The histological hallmark of Parkinson's disease (PD) is the presence of fibrillar aggregates called Lewy bodies (LBs). LB formation has been considered to be a marker for neuronal degeneration, because neuronal loss is found in the predilection sites for LBs. To date, more than 70 molecules have been identified in LBs, in which α-synuclein is a major constituent of LB fibrils. α-synuclein immunohistochemistry reveals that diffuse cytoplasmic staining develops into pale bodies via compaction, and that LBs arise from the peripheral portion of pale bodies. This α-synuclein abnormality is found in 10% of pigmented neurons in the substantia nigra and more than 50% of those in the locus ceruleus in PD. Recent studies have suggested that oligomers and protofibrils of α-synuclein are cytotoxic, and that LBs may represent a cytoprotective mechanism in PD.

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