alpha-synuclein and Calcinosis

The environmental neurotoxin β-N-methylamino-L-alanine (BMAA) has been implicated in the etiology of neurodegenerative disease, and recent studies indicate that BMAA can be misincorporated into proteins. BMAA is a developmental neurotoxicant that can induce long-term learning and memory deficits, as well as regionally restricted neuronal degeneration and mineralization in the hippocampal CA1. The aim of the study was to characterize long-term changes (2 weeks to 6 months) further in the brain of adult rats treated neonatally (postnatal days 9-10) with BMAA (460 mg/kg) using immunohistochemistry (IHC), transmission electron microscopy, and laser capture microdissection followed by LC-MS/MS for proteomic analysis. The histological examination demonstrated progressive neurodegenerative changes, astrogliosis, microglial activation, and calcification in the hippocampal CA1 3-6 months after exposure. The IHC showed an increased staining for α-synuclein and ubiquitin in the area. The ultrastructural examination revealed intracellular deposition of abundant bundles of closely packed parallel fibrils in neurons, axons, and astrocytes of the CA1. Proteomic analysis of the affected site demonstrated an enrichment of chaperones (e.g., clusterin, GRP-78), cytoskeletal and intermediate filament proteins, and proteins involved in the antioxidant defense system. Several of the most enriched proteins (plectin, glial fibrillar acidic protein, vimentin, Hsp 27, and ubiquitin) are known to form complex astrocytic inclusions, so-called Rosenthal fibers, in the neurodegenerative disorder Alexander disease. In addition, TDP-43 and the negative regulator of autophagy, GLIPR-2, were exclusively detected. The present study demonstrates that neonatal exposure to BMAA may offer a novel model for the study of hippocampal fibril formation in vivo.

Topics: alpha-Synuclein; Amino Acids, Diamino; Animals; Animals, Newborn; CA1 Region, Hippocampal; Calcinosis; Chromatography, Liquid; Cyanobacteria Toxins; Cytoskeletal Proteins; Cytoskeleton; Immunohistochemistry; Microscopy, Electron, Transmission; Molecular Chaperones; Protein Folding; Rats, Sprague-Dawley; Tandem Mass Spectrometry; Ubiquitin

Topics: alpha-Synuclein; Brain Diseases; Calcinosis; Cerebellum; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Multiple System Atrophy; Pons

Familial idiopathic brain calcification (FIBC) is a rare disorder characterised by autosomal dominant transmission, adult onset cerebellar and/or extrapyramidal features and idiopathic calcification of the brain. We present a family with FIBC where pathological studies showed that the proband had alpha-synuclein-immunopositive glial and neuronal cytoplasmic inclusions in oligodendrocytes in the putamen, midbrain and pons. This may represent a new and familial alpha-synuclein disorder causing a predominantly extrapyramidal picture similar to multisystem atrophy.

Topics: Adolescent; Adult; alpha-Synuclein; Brain; Calcinosis; Child; Female; Humans; Immunohistochemistry; Inclusion Bodies; Male; Middle Aged; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurofibrillary Tangles; Neuroglia; Pedigree; Plaque, Amyloid; Synucleins; Tomography, X-Ray Computed

alpha-Synuclein is known to be a major constituent of the Lewy bodies (LBs) in Parkinson's disease (PD) and the neuronal and glial cytoplasmic inclusions (NCIs, GCIs) in multiple system atrophy. alpha-Synuclein-positive inclusions such as LBs, NCIs and GCIs sometimes show colocalization with tau-positive neurofilaments. Studies using alpha-synuclein immunohistochemistry have often found LBs in the amygdala of patients with familial or sporadic Alzheimer's disease (AD), as well as in patients with Down's syndrome and AD. However, no studies have reported alpha-synuclein-positive structures in cases of diffuse neurofibrillary tangles with calcification (DNTC), which is characterized by numerous neurofibrillary tangles (NFTs) throughout the cerebral cortex but few, if any, senile plaques. We investigated the distribution of alpha-synuclein-positive structures in two cases of DNTC: a 65-year-old woman (brain weight, 850 g) and a 75-year-old woman (brain weight, 800 g). In both cases, severe cerebral atrophy predominant in the temporal lobe was noted. Microscopically, alpha-synuclein-positive intracytoplasmic inclusions and neurites were found in the superior temporal lobe (within the temporal pole), amygdala, parahippocampus, entorhinal cortex and insula, the regions most affected by the NFTs. alpha-Synuclein-positive intracytoplasmic inclusions were rare or absent in other regions of the cerebral cortex and brainstem. This distribution pattern differs from that of PD or dementia with LBs. Our findings suggest that the accumulation pattern of alpha-synuclein is a pathological feature of DNTC, and that DNTC is associated with accumulation of both tau and alpha-synuclein.

Topics: Aged; alpha-Synuclein; Alzheimer Disease; Brain; Calcinosis; Female; Humans; Immunohistochemistry; Lewy Bodies; Lewy Body Disease; Microscopy, Immunoelectron; Middle Aged; Nerve Tissue Proteins; Neurofibrillary Tangles; Neuroglia; Neurons; Parkinson Disease; Phosphorylation; Synucleins; tau Proteins

Diffuse neurofibrillary tangles with calcification (DNTC) is a rare tangle-predominant dementia, as well as one of the tauopathies lacking Abeta deposition. It is characterized by temporo-frontal lobar atrophy, Fahr-type calcification and, histopathologically, numerous neurofibrillary tangles in the limbic system and neocortex. Recently, accumulation of alpha-synuclein (alphaS), the precursor of the non-beta amyloid component (NAC) of Alzheimer's disease, has been shown in diverse neurodegenerative disorders, including Parkinson's disease, dementia with Lewy bodies, Alzheimer's disease, multiple system atrophy and parkinsonism-dementia complex of Guam. To clarify whether alphaS accumulates in other neurodegenerative disorders, we investigated eight DNTC brains using immunohistochemistry and demonstrated remarkable alphaS deposition in the neurons and astrocytes in many anatomical regions. Abundant Lewy bodies were observed in the amygdala (seven cases) and hippocampus (seven cases), and, to a lesser degree, in the substantia nigra (six cases) and dorsal vagal nucleus (five cases). In the hippocampus, many Lewy neurites were distributed in the stratum oriens and stratum pyramidale in the CA2-3 and the subiculum. Furthermore, numerous NAC-positive astrocytes were detected in the hippocampus and temporal cortex. This investigation reveals that neurons and astrocytes are extensively involved in remarkable alphaS pathology in the DNTC brain, and that the alphaS pathology compounds the cardinal pathological features of tau pathology. These findings suggest that (1) DNTC shares a common pathophysiological background with Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy in which abnormal alphaS aggregation is observed, and (2) there is an interaction between alphaS and tau pathology that does not involve amyloid in DNTC.

Topics: Adult; Aged; alpha-Synuclein; Amyloid; Astrocytes; Brain; Calcinosis; Dementia; Female; Humans; Immunohistochemistry; Lewy Bodies; Male; Middle Aged; Nerve Tissue Proteins; Neurofibrillary Tangles; Neurons; Synucleins; tau Proteins; Ubiquitin