Alpha-synuclein accumulates in Lewy bodies in Parkinson's disease and dementia with Lewy bodies but not in Alzheimer's disease beta-amyloid plaque cores.

A growing body of evidence suggests that the non-Abeta component of Alzheimer's disease amyloid precursor protein (NACP) or alpha-synuclein contributes to the neurodegenerative processes in Alzheimer's disease (AD), Parkinson's disease (PD) and dementia with Lewy bodies (DLB). In the present study antisera to the N terminus and the NAC domain of the alpha-synuclein protein were employed to elucidate the expression pattern in brains of patients with AD, PD, DLB and control specimen. Alpha-synuclein exhibited an overall punctuate expression profile compatible with a synaptic function. Interestingly, while Lewy bodies were strongly immunoreactive, none of the alpha-synuclein antisera revealed staining in mature beta-amyloid plaques in AD. These observations suggest that alpha-synuclein does not contribute to late neurodegenerative processes in AD brains.