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Parkinson's disease (PD) is the second most common neurodegenerative disorder. An important hallmark of PD involves the pathological aggregation of proteins in structures known as Lewy bodies. The major component of these proteinaceous inclusions is alpha (α)-synuclein. In different conditions, α-synuclein can assume conformations rich in either α-helix or β-sheets. The mechanisms of α-synuclein misfolding, aggregation, and fibrillation remain unknown, but it is thought that β-sheet conformation of α-synuclein is responsible for its associated toxic mechanisms. To gain fundamental insights into the process of α-synuclein misfolding and aggregation, the secondary structure of this protein in the presence of charged and non-charged surfactant solutions was characterized. The selected surfactants were (anionic) sodium dodecyl sulphate (SDS), (cationic) cetyltrimethylammonium chloride (CTAC), and (uncharged) octyl β-D-glucopyranoside (OG). The effect of surfactants in α-synuclein misfolding was assessed by ultra-structural analyses, in vitro aggregation assays, and secondary structure analyses. The α-synuclein aggregation in the presence of negatively charged SDS suggests that SDS-monomer complexes stimulate the aggregation process. A reduction in the electrostatic repulsion between N- and C-terminal and in the hydrophobic interactions between the NAC (non-amyloid beta component) region and the C-terminal seems to be important to undergo aggregation. Fourier transform infrared spectroscopy (FTIR) measurements show that β-sheet structures comprise the assembly of the fibrils.

Parkinson's disease, the most common age-related movement disorder, is a progressive neurodegenerative disease with unclear etiology. Key neuropathological hallmarks are Lewy bodies and Lewy neurites: neuronal inclusions immunopositive for the protein α-synuclein. In-depth ultrastructural analysis of Lewy pathology is crucial to understanding pathogenesis of this disease. Using correlative light and electron microscopy and tomography on postmortem human brain tissue from Parkinson's disease brain donors, we identified α-synuclein immunopositive Lewy pathology and show a crowded environment of membranes therein, including vesicular structures and dysmorphic organelles. Filaments interspersed between the membranes and organelles were identifiable in many but not all α-synuclein inclusions. Crowding of organellar components was confirmed by stimulated emission depletion (STED)-based super-resolution microscopy, and high lipid content within α-synuclein immunopositive inclusions was corroborated by confocal imaging, Fourier-transform coherent anti-Stokes Raman scattering infrared imaging and lipidomics. Applying such correlative high-resolution imaging and biophysical approaches, we discovered an aggregated protein-lipid compartmentalization not previously described in the Parkinsons' disease brain.

Background: Chronic neuroinflammation is a hallmark of Parkinson's disease (PD) pathophysiology, associated with increased levels of pro-inflammatory factors in PD brain tissues. The pro-inflammatory mediator and highly amyloidogenic protein S100A9 is involved in the amyloid-neuroinflammatory cascade in Alzheimer's disease. This is the first report on the co-aggregation of α-synuclein (α-syn) and S100A9 both in vitro and ex vivo in PD brain., Methods: Single and sequential immunohistochemistry, immunofluorescence, scanning electron and atomic force (AFM) microscopies were used to analyze the ex vivo PD brain tissues for S100A9 and α-syn location and aggregation. In vitro studies revealing S100A9 and α-syn interaction and co-aggregation were conducted by NMR, circular dichroism, Thioflavin-T fluorescence, AFM, and surface plasmon resonance methods., Results: Co-localized and co-aggregated S100A9 and α-syn were found in 20% Lewy bodies and 77% neuronal cells in the substantia nigra; both proteins were also observed in Lewy bodies in PD frontal lobe (Braak stages 4-6). Lewy bodies were characterized by ca. 10-23 μm outer diameter, with S100A9 and α-syn being co-localized in the same lamellar structures. S100A9 was also detected in neurons and blood vessels of the aged patients without PD, but in much lesser extent. In vitro S100A9 and α-syn were shown to interact with each other via the α-syn C-terminus with an apparent dissociation constant of ca. 5 μM. Their co-aggregation occurred significantly faster and led to formation of larger amyloid aggregates than the self-assembly of individual proteins. S100A9 amyloid oligomers were more toxic than those of α-syn, while co-aggregation of both proteins mitigated the cytotoxicity of S100A9 oligomers., Conclusions: We suggest that sustained neuroinflammation promoting the spread of amyloidogenic S100A9 in the brain tissues may trigger the amyloid cascade involving α-syn and S100A9 and leading to PD, similar to the effect of S100A9 and Aβ co-aggregation in Alzheimer's disease. The finding of S100A9 involvement in PD may open a new avenue for therapeutic interventions targeting S100A9 and preventing its amyloid self-assembly in affected brain tissues.

α-Synuclein (αS) is a neuronal protein that localises predominantly at the presynaptic terminals, and whose fibrillar aggregates are the major constituents of Lewy bodies in Parkinson's disease. In vivo αS is partitioned between water-soluble and membrane-bound states, and this highly regulated equilibrium influences its biological behaviour under both physiological and pathological conditions. Here we discuss the sequence and structural determinants underlying the transition between the unstructured cytosolic and partially structured membrane-bound states of αS. The balance between order and disorder in this protein system is crucial for the overall regulation of the membrane affinity, the ability to induce the clustering of synaptic vesicles, and the tendency to self assemble into amyloid fibrils at the surface of biological membranes., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Aim: to clarify the features of morphochemical changes in the substantia nigra cellular structures in Parkinson's disease., Material and Methods: The structural characteristics of the substantia nigra were studied microscopically and quantified using computer morphometric methods at brain autopsies of individuals with Parkinson's disease who had died from intercurrent diseases and those who had no evidence of neurological disorders in their history (a control group)., Results: This investigation could clarify the features of morphochemical changes in both the neural network structures and the glial populations of the substantia nigra in Parkinson's disease. The number of neurons containing tyrosine hydroxylase (a marker of dopamine neurons) in the compact part of the substantia nigra (a ventral region) was smaller and the density distribution of Lewy bodies was higher in the patients with Parkinson's disease than in the control group. The accumulation of iron (II) compounds in the cellular elements and neuropile and the increased expression of glial fibrillary acidic protein in Parkinson's disease were more pronounced than those in the controls., Conclusion: Postmortem diagnosis in Parkinson's disease should be based on a full description of a set of neuronal and glial morphochemical and structural changes in the substantia nigra rather than on the identification of cellular markers for the neurodegenerative process.

Parkinson's disease (PD) is one of the most common progressive neurodegenerative disorders in modern society. The disease involves many genetic risk factors as well as a sporadic pathogenesis that is age- and environment-dependent. Of particular interest is the formation of intra-neural fibrillar aggregates, namely Lewy bodies (LBs), the histological hallmark of PD, which results from aberrant protein homeostasis or misfolding that results in neurotoxicity. A better understanding of the molecular mechanism and composition of these cellular inclusions will help shed light on the progression of misfolding-associated neurodegenerative disorders. Ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) is found to co-aggregate with α-synuclein (αS), the major component of LBs. Several familial mutations of UCH-L1, namely p.Ile93Met (p.I93M), p.Glu7Ala (p.E7A), and p.Ser18Tyr (p.S18Y), are associated with PD and other neurodegenerative disorders. Here, we review recent progress and recapitulate the impact of PD-associated mutations of UCH-L1 in the context of their biological functions gleaned from biochemical and biophysical studies. Finally, we summarize the effect of these genetic mutations and post-translational modifications on the association of UCHL1 and PD in terms of loss of cellular functions or gain of cellular toxicity., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

α-Synuclein (aS) aggregation has been amply investigated for its involvement in Parkinson's disease because its amyloid fibrils are the main constituent of Lewy bodies, one of the hallmarks of the disease. aS aggregation was studied here in vitro and in cellular models to correlate aggregation products with toxicity mechanisms. Independent results published elsewhere suggested that aS overexpression and/or aggregation may impair cellular metabolism and cause mitochondrial damage. In this context, we report the characterization of changes in NADH fluorescence properties in vitro and in human embryonic kidney 293 cells upon aS aggregation. The application of the phasor approach to study NADH fluorescence lifetime and emission allowed us to identify changes that correlate with aS aggregation. In particular, the fraction of bound NADH, characterized by longer lifetimes in comparison to free NADH, is increased, and the maximum of the NADH emission is shifted toward shorter wavelengths in the presence of aggregating aS both in vitro and in cells. These data suggest that NADH binds to aggregated aS. NMR experiments in vitro substantiate such binding, which occurs during aggregation. NADH fluorescence is thus useful to detect aS aggregation and by extension the associated oxidative stress., (© FASEB.)

A clinicopathological investigation was conducted on a case of an 89-year-old man with a 10-year history of progressive dementia who also suffered strokes, apathy, aphasia, dysarthria, weakness of both legs, and walking difficulties. At autopsy, we found an obvious atrophy of the frontal and temporal cortex. Lewy bodies (LBs) could be seen in brain stem, amygdala, and neocortex. Argyrophilic grains were observed in hippocampus, entorhinal cortex, neocortex, amygdala, and pons, as well as neurofibrillary tangles in the entorhinal cortex and hippocampus. The case presented here is a rare case of frontotemporal lobar degeneration with accumulation of argyrophilic grains and Lewy bodies.

Demyelination is a major contributor to the general decay of neural functions in children with Krabbe disease. However, recent reports have indicated a significant involvement of neurons and axons in the neuropathology of the disease. In this study, we have investigated the nature of cellular inclusions in the Krabbe brain. Brain samples from the twitcher mouse model for Krabbe disease and from patients affected with the infantile and late-onset forms of the disease were examined for the presence of neuronal inclusions. Our experiments demonstrated the presence of cytoplasmic aggregates of thioflavin-S-reactive material in both human and murine mutant brains. Most of these inclusions were associated with neurons. A few inclusions were detected to be associated with microglia and none were associated with astrocytes or oligodendrocytes. Thioflavin-S-reactive inclusions increased in abundance, paralleling the development of neurological symptoms, and distributed throughout the twitcher brain in areas of major involvement in cognition and motor functions. Electron microscopy confirmed the presence of aggregates of stereotypic β-sheet folded proteinaceous material. Immunochemical analyses identified the presence of aggregated forms of α-synuclein and ubiquitin, proteins involved in the formation of Lewy bodies in Parkinson's disease and other neurodegenerative conditions. In vitro assays demonstrated that psychosine, the neurotoxic sphingolipid accumulated in Krabbe disease, accelerated the fibrillization of α-synuclein. This study demonstrates the occurrence of neuronal deposits of fibrillized proteins including α-synuclein, identifying Krabbe disease as a new α-synucleinopathy., (Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.)

Lewy bodies are the hallmark of Parkinson disease and their sophisticated analysis will undoubtedly elucidate the pathogenic process. They have been studied by using different microscopic tools. The authors have used atomic force microscopy (AFM) to study the ultramicrotom cut postmortem brain tissue of Parkinson disease patients. Under the same preparation conditions, they have found aggregated fibrillary nanostructures in Lewy bodies, as well as a loss of connections between neurons located in other parts of the substantia nigra. Although these results are preliminary and descriptive in nature, this paper reports the application of a novel and intriguing technique. Further studies including the study of cortical LB and Lewy neurites will be needed to determine the full potential of AFM in the study of the pathogenesis of cell death in Parkinson disease and other synucleinopathies.

The "proteinopathy" hypothesis, which states that pathological inclusions result in neuronal death, is classically invoked to explain neurodegeneration. In this review on α-synuclein (αS), attention is shifted to the distal axons, where αS deposits earlier than in the cytoplasmic formation of Lewy bodies (LBs). Because LBs are preferentially formed in axons with abundant branching, hyperbranching may accentuate axonal degeneration and αS deposition in their distal ends. This hyperbranching may also explain why motor/non-motor symptoms of Parkinson disease (PD) are so generalized and diffuse with barely any localizing value. Such underlying structure templates both the distal-dominant degeneration with αS deposition, and the non-localizing nature of clinical manifestations of PD, and as such can be considered a "structural template" thereof. The evolution of PD symptoms can be highly variable, ranging from restricted LB lesions and corresponding, long-lived, symptoms (pure autonomic failure, cardiac denervation, essential tremor, and REM-related behavioral disorders, which may be collectively called "focal LB disease") to the more haphazard appearance of dementia or anosmia without developing parkinsonism or brainstem lesions. This variability is better explained by the parallel involvement of multiple systems with hyperbranching axons rather than the stereotyped upward spread of LB in the brainstem. Awareness of presynaptic dysfunctions of these hyperbranching systems may enhance the sensitivity and specificity of clinical diagnoses of PD for earlier therapeutic intervention.

Parkinson's disease (PD) is one of the most common neurodegenerative diseases. It is characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta of the brain. Another feature is represented by the formation in these cells of inclusions called Lewy bodies (LB), principally constituted by fibrillar α-synuclein (αSyn). This protein is considered a key element in the aetiology of a group of neurodegenerative disorders termed synucleinopathies, which include PD, but the cellular and molecular mechanisms involved are not completely clear. It is established that the inflammatory process plays a crucial role in the pathogenesis and/or progression of PD; moreover, it is known that aggregated αSyn, released by neurons, activates microglia cells to produce pro-inflammatory mediators, such as IL-1β. IL-1β is one of the strongest pro-inflammatory cytokines; it is produced as an inactive mediator, and its maturation and activation requires inflammasome activation. In particular, the NLRP3 inflammasome is activated by a wide variety of stimuli, among which are crystallized and particulate material. In this work, we investigated the possibility that IL-1β production, induced by fibrillar αSyn, is involved the inflammasome activation. We demonstrated the competence of monomeric and fibrillar αSyn to induce synthesis of IL-1β, through TLR2 interaction; we found that the secretion of the mature cytokine was a peculiarity of the fibrillated protein. Moreover, we observed that the secretion of IL-1β involves NLRP3 inflammasome activation. The latter relies on the phagocytosis of fibrillar αSyn, followed by increased ROS production and cathepsin B release into the cytosol. Taken together, our data support the notion that fibrillar αSyn, likely released by neuronal degeneration, acts as an endogenous trigger inducing a strong inflammatory response in PD.

Introduction: There is now growing evidence that essential tremor and Parkinson's disease are related., Aim: To present the main findings from epidemiologic, genetic, clinical, imaging and pathologic studies, contrasting evidences for and against an association between essential tremor and Parkinson's disease., Development: We include a complete update of the latest findings regarding the overlap between these two disorders. There is current evidence that a history of essential tremor may herald the onset of Parkinson's disease in a subset of patients. Furthermore, the fact that the risk of essential tremor is significantly increased in relatives of patients with Parkinson's disease suggests the possibility that both conditions are genetically related, probably sharing common hereditary predisposition. Dopaminergic deficit among essential tremor patients in functional imaging studies and recent pathological studies describing Lewy bodies in some essential tremor patients, support further evidence for an overlap between both conditions, at least in a subset of patients., Conclusion: The convergence of all the reviewed data suggests the possible existence of a mixed essential tremor-Parkinson's disease phenotype in some patients. However, further studies are needed to better understand this phenotype.

Background and Purpose: Shortened telomere length has been considered to be associated with various age-related diseases, especially in dementia such as Alzheimer's disease and vascular dementia. However, changes in telomere length in dementia with Lewy bodies (DLB) remain unclear. To elucidate these changes, we set out to determine telomere length in peripheral leukocytes as well as the level of urinary 8-hydroxy-deoxyguanosine (8-OHdG) as a marker of oxidative stress in DLB., Methods: Blood samples were obtained from 33 patients with a clinical diagnosis of probable DLB and 35 age-matched, non-demented elderly controls (NEC). Telomere length was assessed by quantitative real-time polymerase chain reaction of genomic DNA extracted from leukocytes, whereas oxidative stress was assessed on the basis of urine 8-OHdG level, which was measured using high-performance liquid chromatography., Results: Telomere length was significantly shorter in the DLB group than in the NEC group. Urinary 8-OHdG levels were significantly higher in the DLB group than in the NEC group. There was a negative correlation between telomere length and age in the DLB group; however, there were no significant relationships between telomere length and clinical findings including disease duration, severity of cognitive decline, presence or absence of fluctuation in cognitive function, visual hallucinations, and Parkinsonism. In both groups, the correlation between telomere length and urinary 8-OHdG levels was not significant., Conclusions: These findings indicate that the etiopathology of DLB is considered to be an accelerated aging process., (© 2012 The Author(s). European Journal of Neurology © 2012 EFNS.)

Synucleinopathies like Parkinson disease and dementia with Lewy bodies (DLB) are characterized by α-synuclein aggregates within neurons (Lewy bodies) and their processes (Lewy neurites). Whereas α-synuclein has been genetically linked to the disease process, the pathological relevance of α-synuclein aggregates is still debated. Impaired degradation is considered to result in aggregation of α-synuclein. In addition to the ubiquitin-proteasome degradation, the autophagy-lysosomal pathway (ALP) is involved in intracellular degradation processes for α-synuclein. Here, we asked if modulation of ALP affects α-synuclein aggregation and toxicity. We have identified an induction of the ALP markers LAMP-2A and LC3-II in human brain tissue from DLB patients, in a transgenic mouse model of synucleinopathy, and in a cell culture model for α-synuclein aggregation. ALP inhibition using bafilomycin A 1 (BafA1) significantly potentiates toxicity of aggregated α-synuclein species in transgenic mice and in cell culture. Surprisingly, increased toxicity is paralleled by reduced aggregation in both in vivo and in vitro models. The dichotomy of effects on aggregating and nonaggregating species of α-synuclein was specifically sensitive to BafA1 and could not be reproduced by other ALP inhibitors. The present study expands on the accumulating evidence regarding the function of ALP for α-synuclein degradation by isolating an aggregation specific, BafA1-sensitive, ALP-related pathway. Our data also suggest that protein aggregation may represent a detoxifying event rather than being causal for cellular toxicity.

Mutations in the ATP13A2 gene (PARK9, OMIM 610513) cause autosomal recessive, juvenile-onset Kufor-Rakeb syndrome and early-onset parkinsonism. ATP13A2 is an uncharacterized protein belonging to the P(5)-type ATPase subfamily that is predicted to regulate the membrane transport of cations. The physiological function of ATP13A2 in the mammalian brain is poorly understood. Here, we demonstrate that ATP13A2 is localized to intracellular acidic vesicular compartments in cultured neurons. In the human brain, ATP13A2 is localized to pyramidal neurons within the cerebral cortex and dopaminergic neurons of the substantia nigra. ATP13A2 protein levels are increased in nigral dopaminergic and cortical pyramidal neurons of Parkinson's disease brains compared with normal control brains. ATP13A2 levels are increased in cortical neurons bearing Lewy bodies (LBs) compared with neurons without LBs. Using short hairpin RNA-mediated silencing or overexpression to explore the function of ATP13A2, we find that modulating the expression of ATP13A2 reduces the neurite outgrowth of cultured midbrain dopaminergic neurons. We also find that silencing of ATP13A2 expression in cortical neurons alters the kinetics of intracellular pH in response to cadmium exposure. Furthermore, modulation of ATP13A2 expression leads to reduced intracellular calcium levels in cortical neurons. Finally, we demonstrate that silencing of ATP13A2 expression induces mitochondrial fragmentation in neurons. Oppositely, overexpression of ATP13A2 delays cadmium-induced mitochondrial fragmentation in neurons consistent with a neuroprotective effect. Collectively, this study reveals a number of intriguing neuronal phenotypes due to the loss- or gain-of-function of ATP13A2 that support a role for this protein in regulating intracellular cation homeostasis and neuronal integrity.

Background: Lewy body in the substantia nigra is a cardinal pathological feature of Parkinson's disease. Despite enormous efforts, the cause-and-effect relationship between Lewy body formation and the disorder is yet to be explicitly unveiled., Methodology/principal Findings: Here, we showed that radiating amyloid fibrils (RAFs) were instantly developed on the surface of synthetic lipid membranes from the β-sheet free oligomeric species of α-synuclein through a unit-assembly process. The burgeoning RAFs were successfully matured by feeding them with additional oligomers, which led to concomitant dramatic shrinkage and disintegration of the membranes by pulling off lipid molecules to the extending fibrils. Mitochondria and lysosomes were demonstrated to be disrupted by the oligomeric α-synuclein via membrane-dependent fibril formation., Conclusion: The physical structure formation of amyloid fibrils, therefore, could be considered as detrimental to the cells by affecting membrane integrity of the intracellular organelles, which might be a molecular cause for the neuronal degeneration observed in Parkinson's disease.

Diffuse neurofibrillary tangles with calcification (DNTC) is a relatively rare presenile dementia that clinically shows overlapping symptoms of Alzheimer's disease and frontotemporal lobar degeneration (FTLD). DNTC is pathologically characterized by localized temporal or frontotemporal atrophy with massive neurofibrillary tangles, neuropil threads and Fahr's-type calcification without senile plaques. We tried to clarify the molecular basis of DNTC by immunohistochemically examining the appearance and distribution of accumulated alpha-synuclein (aSyn) and TAR DNA-binding protein of 43kDa (TDP-43) in the brains of 10 Japanese autopsy cases. We also investigated the clinically characteristic symptoms from the clinical charts and previous reports, and the correlations with neuropathological findings. The characteristic symptoms were evaluated using the Neuropsychiatric Inventory Questionnaire (NPI-Q). As a result, we confirmed the high frequency of neuronal cytoplasmic accumulation of aSyn (80%) and phosphorylated TDP-43 (90%) in DNTC cases. There was a significant correlation between some selected items of NPI-Q scores and the severity of the limbic TDP-43 pathology. The pathology of DNTC included TDP-43 and aSyn pathology with high frequency. These abnormal accumulations of TDP-43 might be involved in the pathological process of DNTC, having a close relationship to the FTLD-like psychiatric symptoms during the clinical course., (Copyright © 2010 Elsevier B.V. All rights reserved.)

CD3ζ is a subunit of the CD3 molecule that, until recently, appeared restricted to T cells and natural killer cells. However, experimental studies have demonstrated a role of CD3ζ in dendritic outgrowth in the visual system as well as in synaptic plasticity. Given the increasing evidence for uncharacteristic recapitulation of neurodevelopmental processes in neurodegenerative diseases, in this study, we evaluated brains from subjects with Parkinson's disease and Lewy body dementia for evidence of aberrant CD3 expression. Our data shows marked CD3ζ in association with the α-synuclein containing pathological lesions, i.e., Lewy bodies and Lewy neurites, in the brains of subjects with Parkinson's disease and Lewy body dementia. This finding raises the novel concept of CD3 dysregulation in these disorders as a pathogenic factor and also furthers the increasing evidence that the recall of aberrant neurodevelopmental processes underlies the pathogenesis of neurodegenerative diseases.

Abnormally modified alpha-synuclein is a pathological hallmark of Parkinson's disease and the other alpha-synucleinopathies. Since proteinase K (PK) treatment is known to enhance the immunoreactivity of abnormal alpha-synuclein, we immunohistochemically examined the brain of transgenic (Tg) mice expressing human mutant A53T alpha-synuclein using this retrieval method. PK treatment abolished the immunoreactivity of alpha-synuclein in abnormal inclusions as well as of endogenous alpha-synuclein in Tg mice, whereas PK-resistant alpha-synuclein was found in the presynaptic nerve terminals, especially in the hippocampus and temporal cortex. In human Lewy body disease, PK-resistant alpha-synuclein was deposited in Lewy bodies and Lewy neurites, as well as in the presynapses in distinct brain regions, including the hippocampus, temporal cortex and substantia nigra. Biochemical analysis revealed that PK-resistant alpha-synuclein was detected in the presynaptic fraction in Tg mice and human Lewy body disease. Although PK-resistant alpha-synuclein was found in the presynapse in Tg mice even at 1 week of age, it was not phosphorylated until at least 8 months of age. Moreover, PK-resistant alpha-synuclein in the presynapse was not phosphorylated in human Lewy body disease. These findings suggest that phosphorylation is not necessary to cause the conversion of soluble form to PK-resistant alpha-synuclein. Considering that native alpha-synuclein is a soluble protein localized to the presynaptic terminals, our findings suggest that PK-resistant alpha-synuclein may disturb the neurotransmission in alpha-synucleinopathies.

We previously reported the occurrence of Lewy bodies in grafted human fetal mesencephalic neurons in two patients with Parkinson's disease. Here, we have used immunohistochemistry and electron microscopy to characterize the development of Lewy bodies in one of these cases. This patient was operated in putamen on both sides at 12 or 16 years before death, respectively. We demonstrate that 2% of the 12-year-old and 5% of the 16-year-old grafted, presumed dopaminergic neurons contained Lewy bodies immunoreactive for alpha-synuclein. Based on morphological analysis, two forms of alpha-synuclein-positive aggregates were distinguished in the grafts, the first a classical and compact Lewy body, the other a loose meshwork aggregate. Lewy bodies in the grafts stained positively for ubiquitin and thioflavin-S, and contained characteristic alpha-synuclein immunoreactive electron dense fibrillar structures on electron microscopy. Our data indicate that Lewy bodies develop gradually in transplanted dopaminergic neurons in a fashion similar to that in dopaminergic neurons in the host substantia nigra., ((c) 2010 Movement Disorder Society.)

Introduction: Cognitive disorders such as deficit of attention and executive and visuoconstructive dysfunctions occur in Parkinson's disease dementia (PDD). Memory impairment is not an early feature and statement not well delimited., Case Report: A 78-year-old man with PDD underwent neuropsychological assessment and moreover demonstrated memory decline. After death, pathology examination of the brain and immunohistochemy analysis confirmed PD and showed Lewy body pathology (LBP) in the insula, limbic and especially in CA3 hippocampus areas. Hippocampus and gyrus parahippocampic also exhibited neurofibrillary tangles. Lack of senile plaque and lack of beta A4 amyloid deposition were noticeable in the whole brain examination., Conclusion: Severe executive dysfunctions are probably related to LBP and dysfunction in memory process may be related to DNF lesions in medial temporal area.

Misfolding and aggregation of proteins are characteristics of a range of increasingly prevalent neurodegenerative disorders including Alzheimer's and Parkinson's diseases. In Parkinson's disease and several closely related syndromes, the protein alpha-synuclein (AS) aggregates and forms amyloid-like deposits in specific regions of the brain. Fluorescence microscopy using fluorescent proteins, for instance the yellow fluorescent protein (YFP), is the method of choice to image molecular events such as protein aggregation in living organisms. The presence of a bulky fluorescent protein tag, however, may potentially affect significantly the properties of the protein of interest; for AS in particular, its relative small size and, as an intrinsically unfolded protein, its lack of defined secondary structure could challenge the usefulness of fluorescent-protein-based derivatives. Here, we subject a YFP fusion of AS to exhaustive studies in vitro designed to determine its potential as a means of probing amyloid formation in vivo. By employing a combination of biophysical and biochemical studies, we demonstrate that the conjugation of YFP does not significantly perturb the structure of AS in solution and find that the AS-YFP protein forms amyloid deposits in vitro that are essentially identical with those observed for wild-type AS, except that they are fluorescent. Of the several fluorescent properties of the YFP chimera that were assayed, we find that fluorescence anisotropy is a particularly useful parameter to follow the aggregation of AS-YFP, because of energy migration Förster resonance energy transfer (emFRET or homoFRET) between closely positioned YFP moieties occurring as a result of the high density of the fluorophore within the amyloid species. Fluorescence anisotropy imaging microscopy further demonstrates the ability of homoFRET to distinguish between soluble, pre-fibrillar aggregates and amyloid fibrils of AS-YFP. Our results validate the use of fluorescent protein chimeras of AS as representative models for studying protein aggregation and offer new opportunities for the investigation of amyloid aggregation in vivo using YFP-tagged proteins., (Copyright 2009 Elsevier Ltd. All rights reserved.)

Purkinje cell axonal swellings ("torpedoes"), described in several cerebellar disorders as well as essential tremor (ET), have not been quantified in common neurodegenerative conditions. The aim of this study was to quantify torpedoes Parkinson's disease (PD) and Alzheimer's disease (AD) compared with ET and control brains. Brains included 40 ET cases (34 cerebellar ET, 6 Lewy body variant of ET) and age-matched comparison brains (21 AD, 14 PD/diffuse Lewy body disease, 25 controls). Torpedoes were counted in 20 x 25 mm cerebellar cortical sections stained with Luxol Fast Blue/Hematoxylin and Eosin. The median number of torpedoes in cerebellar ET (12) was 12x higher than that of controls (1) and nearly 2.5x higher than in AD (5) or PD/DLBD (5) (all P < or = 0.005). Furthermore, in a logistic regression model that adjusted for age and Alzheimer's-type changes, each torpedo more than doubled the odds of having cerebellar ET (Odds ratio(cerebellar ET vs. control) = 2.57, P = 0.006), indicating that the association between increased torpedoes and cerebellar ET was independent of these Alzheimer's-type changes. Although torpedoes are increased in AD and PD, as well as cerebellar ET, the magnitude of increase in cerebellar ET is greater, and cannot be accounted for by concomitant AD or PD pathology., (2009 Movement Disorder Society.)

alpha-Synuclein is the major component of the filamentous Lewy bodies and Lewy-related neurites, neuropathological hallmarks of Parkinson's disease. Although numerous studies on alpha-synuclein fibrillation have been reported, the molecular mechanisms of aggregation and fibrillation at the initial stage are still unclear. In the present study, structural properties and propensities to form fibrils of alpha-synuclein at the initial stage were investigated using 2D (1)H-(15)N NMR spectroscopy, electron microscope, and small angle X-ray scattering (SAXS). Observation of the 2D (1)H-(15)N HSQC spectra indicated significant attenuation of many cross peak intensities in the regions of KTKEGV-type repeats and the non-Abeta component of Alzheimer's disease amyloid (NAC), suggesting that these regions contributed fibril formation. Oligomerization comprising heptamer was successfully monitored at the initial stage using the time-dependent SAXS measurements.

Aggregated alpha-synuclein (alpha-syn) fibrils form Lewy bodies (LBs), the signature lesions of Parkinson's disease (PD) and related synucleinopathies, but the pathogenesis and neurodegenerative effects of LBs remain enigmatic. Recent studies have shown that when overexpressed in Saccharomyces cerevisiae, alpha-syn localizes to plasma membranes and forms cytoplasmic accumulations similar to human alpha-syn inclusions. However, the exact nature, composition, temporal evolution, and underlying mechanisms of yeast alpha-syn accumulations and their relevance to human synucleinopathies are unknown. Here we provide ultrastructural evidence that alpha-syn accumulations are not comprised of LB-like fibrils, but are associated with clusters of vesicles. Live-cell imaging showed alpha-syn initially localized to the plasma membrane and subsequently formed accumulations in association with vesicles. Imaging of truncated and mutant forms of alpha-syn revealed the molecular determinants and vesicular trafficking pathways underlying this pathological process. Because vesicular clustering is also found in LB-containing neurons of PD brains, alpha-syn-mediated vesicular accumulation in yeast represents a model system to study specific aspects of neurodegeneration in PD and related synucleinopathies.

We intensively examined the spinal cord of an autosomal recessive juvenile parkinsonism (ARJP) female patient with a homozygous exon 3 deletion in the parkin gene, anticipating a possible involvement of anterior horn neurons. Although the clinical features of the patient were consistent with parkinsonism as a result of parkin mutation, her tendon reflex was abolished in the lower limbs. This feature was in contrast with hyperreflexia, usually found in previous reports of ARJP. Histologically, on the level of the cervical, thoracic, and sacral spinal cord, anterior horn neurons were well preserved and normal. However, the lumbar spinal cord exhibited many swellings of proximal axons (spheroids) and degenerative changes in the somata of the large anterior horn neurons such as central chromatolysis, cystatin C-negative small eosinophilic inclusions, and eosinophilic Lewy body-like inclusions. Ultrastructurally, accumulations of neurofilaments and abnormal structures, such as inclusion bodies similar to skein-like inclusions and disorganized rough endoplasmic reticulum, were observed in the somata and neuronal processes. Lewy body-like inclusions in this study were positively immunostained for both alpha-synuclein and ubiquitin that closely resemble Lewy bodies, but are different from Lewy body-like inclusions negatively immunostained for alpha-synuclein in amyotrophic lateral sclerosis. These findings suggest that eosinophilic inclusions that closely resemble Lewy bodies may be formed in the spinal motor neurons of ARJP patients with parkin mutations and the motor neurons of these patients may be vulnerable to neurodegeneration.

Two missense mutations (P123H and V70M) of beta-synuclein (beta-syn), the homologue of alpha-syn, have been recently identified in dementia with Lewy bodies. However, the mechanism through which these mutations influence the pathogenesis of dementia with Lewy bodies is unclear. To investigate the role of the beta-syn mutations in neurodegeneration, each mutant was stably transfected into B103 neuroblastoma cells. Cells overexpressing mutated beta-syn had eosinophilic cytoplasmic inclusion bodies immunopositive for mutant beta-syn, and electron microscopy revealed that these cells were abundant in various cytoplasmic membranous inclusions resembling the histopathology of lysosomal storage disease. Consistent with these findings, the inclusion bodies were immunopositive for lysosomal markers, including cathepsin B, LAMP-2, GM2 ganglioside, and ATP13A2, which has recently been linked to PARK9. Notably, formation of these lysosomal inclusions was greatly stimulated by co-expression of alpha-syn, was dependent on the phosphorylation of alpha-syn at Ser-129, and was more efficient with the A53T familial mutant of alpha-syn compared with wild type. Furthermore, the inclusion formation in cells overexpressing mutant beta-syn and transfected with alpha-syn was significantly suppressed by treatment with autophagy-lysosomal inhibitors, which were associated with impaired clearance of syn proteins and enhanced apoptosis, indicating that formation of lysosomal inclusions might be protective. Collectively, the results demonstrated unambiguously that overexpression of beta-syn mutants (P123H and V70M) in neuroblastoma cells results in an enhanced lysosomal pathology. We suggest that these missense mutations of beta-syn might play a causative role in stimulating neurodegeneration.

Astrocytic alpha-synuclein-immunoreactive inclusions have recently been noted to develop in sporadic Parkinson's disease (PD). Here, the presence of immunoreactive astrocytes is reported in 14 autopsy cases with clinically diagnosed PD and a neuropathological stage of 4 or higher. The labeled astrocytes occur preferentially in prosencephalic regions (amygdala, thalamus, septum, striatum, claustrum, and cerebral cortex). They appear first in layers V-VI of the temporal mesocortex, then in the striatum and in thalamic nuclei that project to the cortex. The topographical distribution pattern of these astrocytes closely parallels that of the cortical intraneuronal Lewy neurites and Lewy bodies, which, from their foothold in the mesocortex, gradually encroach upon neocortical association areas and even the primary fields. Thus, labeling of astrocytes appears to accompany the formation of neuronal inclusion bodies. Relatively small immunoreactive cortical pyramidal neurons in layers V-VI probably project to nearby destinations, such as the striatum and thalamus. Inasmuch as the projection neurons of both the striatum and the dorsal thalamus do not develop Lewy bodies, it is suggested that the most likely cause of the astrocytic reaction may be a slightly altered alpha-synuclein molecule that escapes from terminal axons of affected cortico-striatal or cortico-thalamic neurons and is taken up by astrocytes. Other aggregated proteins known to co-occur with PD-associated intraneuronal lesions, e.g., Abeta protein or neurofibrillary changes of the Alzheimer type, do not appear to influence the development of the alpha-synuclein immunoreactive astrocytes.

Lewy bodies (LBs) are alpha-synuclein-immunoreactive neuronal inclusions with a predilection for specific cortical and subcortical regions, including the amygdala. In this study, the presence of LBs was assessed in 347 cases of Alzheimer disease (AD). In 87 cases, LB pathology was diagnostic of brainstem (n=3), transitional (n=32), or diffuse (n=52) Lewy body disease (LBD). The remaining 260 cases of AD were screened for amygdala LBs (AD/ALB) and 62 (24%) cases were found. If AD/LBD cases are included, LBs were detected in 149 (43%) cases of AD. The presence alpha-synuclein pathology was assessed in multiple brain regions of the 62 cases of AD/ALB and 57 randomly selected cases of AD, and only sparse alpha-synuclein pathology was detected in both. The burden of alpha-synuclein pathology in brainstem nuclei, amygdala, and neocortex was significant lower in AD/ALB than in AD/LBD. In comparison to AD/LBD, AD/ALB did not differ in age at death, disease duration, male-to-female ratio, brain weight, Braak neurofibrillary tangle stage, average senile plaque density, or apolipoprotein E epsilon4 allele frequency. The results suggest that AD/ALB is pathologically different from AD/LBD, suggesting that it is a neuropathologically distinct and isolated alpha-synucleinopathy.

Mutations in the genes coding for alpha-synuclein and parkin cause autosomal-dominant and autosomal-recessive forms of Parkinson's disease (PD), respectively. Alpha-synuclein is a major component of Lewy bodies, the proteinaceous cytoplasmic inclusions that are the pathological hallmark of idiopathic PD. Lewy bodies appear to be absent in cases of familial PD associated with mutated forms of parkin. Parkin is an ubiquitin E3 ligase, and it may be involved in the processing and/or degradation of alpha-synuclein, as well as in the formation of Lewy bodies. Here we report the behavioral, biochemical, and histochemical characterization of double-mutant mice overexpressing mutant human A53T alpha-synuclein on a parkin null background. We find that the absence of parkin does not have an impact on the onset and progression of the lethal phenotype induced by overexpression of human A53T alpha-synuclein. Furthermore, all major behavioral, biochemical, and morphological characteristics of A53T alpha-synuclein-overexpressing mice are not altered in parkin null alpha-synuclein-overexpressing double-mutant mice. Our results demonstrate that mutant alpha-synuclein induces neurodegeneration independent of parkin-mediated ubiquitin E3 ligase activity in nondopaminergic systems and suggest that PD caused by alpha-synuclein and parkin mutations may occur via independent mechanisms.

Lewy bodies (LB) in the substantia nigra are a cardinal pathological feature of Parkinson's disease, but they occur in a number of neurodegenerative diseases and can be widespread in the nervous system. The characteristics, locations, and composition of LB are reviewed, with particular attention to alpha-synuclein (alpha-SYN), which appears to be the major component of LB. The propensity for alpha-SYN, a presynaptic protein widely expressed in the brain, to aggregate is because of an amyloidogenic central region. The factors that favor the aggregation of alpha-SYN and mechanisms of toxicity are examined, and a mechanism through which aggregates of alpha-SYN could induce mitochondrial dysfunction and/or release of proapoptotic molecules is proposed.

Lewy bodies (LBs) are the characteristic inclusions of Parkinson's disease brain but the mechanism responsible for their formation is obscure. Lewy bodies (LBs) are composed of a number of proteins of which alpha-synuclein (alpha-SYN) is a major constituent. In this study, we have investigated the distribution patterns of synphilin-1 and parkin proteins in control and sporadic PD brain tissue by immunohistochemistry (IH), immunoblotting, and immunoelectron microscopy (IEM). We demonstrate the presence of synphilin-1 and parkin in the central core of a majority of LBs using IH and IEM. Using IH, we show an overlapping distribution profile of the two proteins in central neurons. Additionally, we show sensitivity of both endogenous synphilin-1 and parkin to proteolytic dysfunction and their co-localization in aggresomes formed in response to the proteasome inhibitor MG-132. We confirm that synphilin-1 and parkin are components of majority of LBs in Parkinson's disease and that both proteins are susceptible to proteasomal degradation.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by selective loss of dopaminergic neurons and the presence of Lewy bodies. Previous reports have shown that alpha-synuclein deposited in brain tissue from individuals with synucleinopathy is extensively phosphorylated at Ser-129. Here, we investigate the role of phosphorylation of alpha-synuclein in the formation of inclusions involving synphilin-1 and parkin using site-directed mutagenesis to change Ser-129 of alpha-synuclein to alanine (S129A) to abolish phosphorylation at this site. Coexpression of wild-type alpha-synuclein and synphilin-1 in human neuroblastoma SH-SY5Y cells yielded cytoplasmic eosinophilic inclusions with some features resembling Lewy bodies, whereas coexpression of S129A alpha-synuclein and synphlin-1 formed few or no inclusions. Moreover, coexpression of parkin with alpha-synuclein and synphilin-1 formed more ubiquitinated inclusions, but these inclusions decreased with expression of S129A alpha-synuclein instead of wild-type alpha-synuclein. Coimmunoprecipitation assays revealed a decreased interaction of S129A alpha-synuclein with synphilin-1 compared with wild-type alpha-synuclein. Expression of S129A alpha-synuclein instead of wild-type alpha-synuclein also decreased the association of synphilin-1 and parkin and subsequently reduced the parkin-mediated ubiquitination of synphilin-1 and the formation of ubiquitinated inclusions. Treatment of SH-SY5Y cells with H(2)O(2) increased alpha-synuclein phosphorylation and enhanced the formation of inclusions formed by coexpression of alpha-synuclein, synphilin-1, and parkin, whereas treatment with the casein kinase 2 inhibitor 5,6-dichloro-1-beta-d-ribofuranosylbenzimidazole had the opposite affect. These results indicate that phosphorylation of alpha-synuclein at S129 may be important for the formation of inclusions in PD and related alpha synucleinopathies.

Recent studies have shown that neurofibrillary tangles are frequently accompanied by alpha-synuclein inclusions in sporadic and familial Alzheimer disease, in Down syndrome, in progressive supranuclear palsy, and Parkinsonism dementia complex of Guam. Here we report the cases of 2 brothers with familial progressive aphasia who developed features of frontotemporal dementia with predominant tau pathology but also alpha-synuclein pathology. The 2 patients' brains revealed abundant tau pathology in the hippocampus and basal ganglia, whereas tau and alpha-synuclein aggregates coexisted only in the nucleus basalis of Meynert, the only region where alpha-synuclein was present. In this brain region, abundant Lewy bodies, Lewy neurites, and tau inclusions were found; the pathology was more abundant in the older than in the younger brother. Sarkosyl-insoluble tau extracted from brains of the 2 patients showed the presence of tau filaments that contained 3 major tau bands of 60, 64, and 68 kDa on Western blot analysis. These bands contained mainly tau with 3 and 4 repeats and no amino-terminal inserts and tau with 4 repeats and one amino-terminal insert. No mutations were identified in the tau, alpha-synuclein, beta-synuclein, or parkin genes. We think that this is the first report showing a specific colocalization of neurofibrillary tangles and Lewy bodies in a family with progressive aphasia.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) has long been recognized as a classical glycolytic protein; however, previous studies by our group and others have demonstrated that GAPDH is a general mediator initiating one or more apoptotic cascades. Our most recent findings have elucidated that an expression of a pro-apoptotic protein GAPDH is critically regulated at the promoter region of the gene. Apoptotic signals for its subsequent aggregate formation and nuclear translocation are controlled by the respective functional domains harboured within its cDNA component. In this study, coexpression of GAPDH with either wild-type or mutant (A53T) alpha-synuclein and less likely with beta-synuclein in transfected COS-7 cells was found to induce Lewy body-like cytoplasmic inclusions. Unlike its full-length construct, the deleted mutant GAPDH construct (C66) abolished these apoptotic signals, disfavouring the formation of inclusions. The generated inclusions were ubiquitin- and thioflavin S-positive appearing fibrils. Furthermore, GAPDH coimmunoprecipitated with wild-type alpha-synuclein in this paradigm. Importantly, immunohistochemical examinations of post mortem materials from patients with sporadic Parkinson's disease revealed the colocalized profiles immunoreactive against these two proteins in the peripheral zone of Lewy bodies from the affected brain regions (i.e. locus coeruleus). Moreover, a quantitative assessment showed that about 20% of Lewy bodies displayed both antigenicities. These results suggest that pro-apoptotic protein GAPDH may be involved in the Lewy body formation in vivo, probably associated with the apoptotic death pathway.

The authors report the clinical and postmortem neuropathologic findings of two patients, one with Parkinson disease (PD) and one with dementia with Lewy bodies (DLB), both of whom initially sought treatment for isolated autonomic failure. These cases suggest that neurodegeneration in PD and DLB may begin outside the CNS in autonomic postganglionic neurons, a finding with potential diagnostic and therapeutic implications.

Many models of Parkinson's disease (PD) have succeeded in replicating dopaminergic neuron loss or alpha-synuclein aggregation but not the formation of classical Lewy bodies, the pathological hallmark of PD. Our cybrid model of sporadic PD was created by introducing the mitochondrial genes from PD patients into neuroblastoma cells that lack mitochondrial DNA. Previous studies using cybrids have shown that information encoded by mitochondrial DNA in patients contributes to many pathogenic features of sporadic PD. In this paper, we report the generation of fibrillar and vesicular inclusions in a long-term cybrid cell culture model that replicates the essential antigenic and structural features of Lewy bodies in PD brain without the need for exogenous protein expression or inhibition of mitochondrial or proteasomal function. The inclusions generated by PD cybrid cells stained with eosin, thioflavin S, and antibodies to alpha-synuclein, ubiquitin, parkin, synphilin-1, neurofilament, beta-tubulin, the proteasome, nitrotyrosine, and cytochrome c. Future studies of these cybrids will enable us to better understand how Lewy bodies form and what role they play in the pathogenesis of PD.

Two mutations in the DJ-1 gene on chromosome1p36 have been identified recently to cause early-onset, autosomal recessive Parkinson's disease. As no information is available regarding the distribution of DJ-1 protein in the human brain, in this study we used a monoclonal antibody for DJ-1 to map its distribution in frontal cortex and substantia nigra, regions invariably involved in Parkinson's disease. Western blotting of human frontal cortex showed DJ-1 to be an abundant protein in control, idiopathic Parkinson's disease, cases with clinical and pathological phenotypes of Parkinson's disease with R98Q polymorphism for DJ-1, and in progressive supranuclear palsy (PSP) brains. We also showed that DJ-1 immunoreactivity (IR) was particularly prominent in astrocytes and astrocytic processes in both control and Parkinson's disease frontal cortex, whereas neurons showed light or no DJ-1 IR. Only occasional Lewy bodies (LBs), the pathological hallmarks of Parkinson's disease, showed faint DJ-1 IR, localized to the outer halo. In preclinical studies we showed that DJ-1 is expressed in primary hippocampal and astrocyte cultures of mouse brain. By 2D gel analysis we also showed multiple pI isoforms for DJ-1 ranging between 5.5-6.6 in both control and Parkinson's disease brains, whilst exposure of M17 cells to the oxidizing agent paraquat was manifested as a shift in pI of endogenous DJ-1 towards more acidic isoforms. We conclude that DJ-1 is not an essential component of LBs and Lewy neurites, is expressed mainly by astrocytes in human brain tissue and is sensitive to oxidative stress conditions. These results are consistent with the hypothesis that neuronal-glial interactions are important in the pathophysiology of Parkinson's disease.

Parkinson's disease (PD) is a multifactorial disease that appears to arise from the effects of both genetic and environmental influences. Pesticides and heavy metals are the principle environmental factors that appear to impact on PD. The known genetic factors include multiple genes that have been identified in related parkinsonian syndromes, as well as alpha-synuclein. Genes associated with either PD or Parkinson-related disorders include parkin, DJ-1, ubiquitin C-terminal hydrolase isozyme L1 (UCH-L1), nuclear receptor-related factor 1, and alpha-synuclein. Alpha-synuclein is particularly notable because it aggregates readily and is the main component of Lewy bodies (LBs). Aggregated alpha-synuclein binds the proteasome and potently inhibits proteasomal activity. Because ubiquitin accumulates in LBs, and parkin and UCH-L1 also interact with the ubiquitin proteasomal system, proteasomal dysfunction is thought to contribute to the pathophysiology of PD. Increasing numbers of experiments suggest that neurotoxins might interact with alpha-synuclein or other Parkinson-related proteins to contribute to the pathophysiology of PD. Transgenic animal models overexpressing alpha-synuclein develop age-dependent motor dysfunction and inclusions in the brain stem that contain alpha-synuclein. These models are very helpful in elucidating the pathophysiology of PD but do not completely recapitulate the disease process. The relationship between these transgenic models and PD is a subject of intense investigation.

Diffuse Lewy body disease (DLBD) is characterized by the presence of Lewy bodies (LB) in the neurons and neurites of cortical, subcortical, and brain stem structures. Recently, alpha-synuclein (alphaS) has been found to be a central constituent of LB. In DLBD, abnormal accumulation of alphaS has been reported in both neurons and glia, but studies on glial lesions in DLBD have been limited. We examined in detail the constituents and distribution of glial lesions in eight patients with DLBD and report the pathogenesis of the glial lesions. alphaS-positive neuronal cytoplasmic inclusions (NI), neuropil threads (NT), and coiled bodies (CB) showed similar immunostaining profiles. Without pretreatment, NI, NT, and CB were detected by all antibodies against alphaS. The immunostaining profile of star-like astrocytes (SLA) was quite different from those of NI, NT, and CB. A few SLA were stained by an antibody against the non-Abeta component portion of alphaS without pretreatment, but formic acid pretreatment dramatically enhanced SLA immunoreactivity. SLA and CB were found in all eight brains with DLBD. SLA were scarce in the brain stem, but there were hundreds of SLA per visual field at x100 magnification in the temporal cortex of most cases, while CB were found diffusely in both the cerebral cortex and brain stem, similar to NI. This suggests that the pathogenesis of SLA is different from those of NI and CB.

The morphological background of cognitive and emotional impairments in Parkinson's disease (PD) has not yet been fully explained. We evaluated the expression of synaptic proteins: alpha- and beta-synuclein, synaptophysin and synaptobrevin and ultrastructural changes of perikaryons and axons in limbic structures at post-mortem from cases of PD to estimate degenerative axonal pathology in the hippocampus and amygdala [corrected]. Limbic structures (enthorinal cortex, hippocampus, and amygdala) are essential for the cognitive processes and emotional behaviour. We found that presynaptic axon pathology is mostly connected with hippocampal CA2-3 and dentate hilar regions as well as with the cortical and medio-central complexes of amygdala. Heterogeneous immunoreactivity of alpha-synuclein and diversified ultrastructure of Lewy bodies (LBs) and Lewy neurites (LNs) indicate their consecutive developmental stages. We observed an excessive perineuroneal expression of synaptophysin in the dentate hilar region in all PD cases, except one. This suggests that the dysfunction of synapses in this region may result from axonal pathology. Our study indicates a relation between cognitive and behavioural symptomatology in PD and alpha-synuclein dependent axonal pathology in the hippocampus and amygdala.

Dementia with Lewy bodies brains were immunohistochemically investigated using anti-synphilin-1 antibodies. The alpha-synuclein-positive brainstem type and well-defined cortical type Lewy bodies (LB) were positive for synphilin-1, while ill-defined LB and LB-related neurites were negative, suggesting that synphilin-1 does not directly associate with alpha-synuclein. Synphilin-1-positive LB were double-positive for phosphorylated neurofilament. In addition, tau-positive neurofibrillary tangles (NFT) were positive for synphilin-1, while neuropil threads were negative. Immunoelectron microscopically, synphilin-1 was located on filamentous components in cortical type LB and on paired helical filaments in NFT. It is likely that synphilin-1 accumulates in the cell body according to the axonal transport blockage, and associates with abnormal cytoskeltons during the formation of LB or NFT, suggesting that synphilin-1 is non-specifically implicated in the formation of different neuronal cytoskeletal inclusions.

Parkinson's disease (PD) and progressive supranuclear palsy (PSP) are distinct neurodegenerative disorders. We describe an 81-year-old woman with 3 years of progressive gait unsteadiness, frequent falls, and mild cognitive dysfunction, all considered clinically to be an early fronto-temporal neurodegenerative disorder. She died of an acute myocardial infarction. Examination of her brain revealed alpha-synuclein- and tau-positive inclusions diagnostic of PD and PSP. Immunoelectron microscopy and Western blot analysis confirmed combined PD/PSP. This case provides strategies for the reliable molecular validation of concomitant PD and PSP, and demonstrates the utility of these techniques in patients with atypical clinical presentations.

Immunohistochemical localization of tau in the cerebellar cortex was carried out using a mouse monoclonal antibody against phosphorylation-dependent tau (AT8) in brain tissue (cerebellum) from 13 patients with progressive supranuclear palsy (PSP), 7 patients with corticobasal degeneration (CBD) and 5 age-matched control subjects. Purkinje cell somata that showed diffuse granular accumulation of cytoplasmic tau were found occasionally in 9 of the 13 patients with PSP (69%) and in 4 of the 7 patients with CBD (57%). Tau-positive doughnut-shaped structures were also found occasionally in the cerebellar molecular layer in 6 of the 13 patients with PSP (46%) and 2 of the 7 patients with CBD (29%). No tau immunoreactivity was detected in the cerebellar cortex in the control tissue. In the tissue from one patient with PSP, we also performed a double-labeling immunofluorescence study with anti-glial fibrillary acidic protein (GFAP) antibody and AT8, as well as an immuno-electron microscopic study with AT8. In tau-positive Purkinje cell somata and dendrites, the reaction product was localized mainly within the rough endoplasmic reticulum and free ribosomes. Tau-positive doughnut-shaped structures were located in the GFAP-positive radial processes of Bergmann's glia and were present in the outer areas of inclusions reminiscent of Lewy bodies, which consist of aggregated pathological tau filaments. In conclusion, we have demonstrated a novel tau pathology that affects Purkinje cells and Bergmann's glia in patients with PSP and CBD, indicating that the cerebellar cortex can be involved in the disease processes in PSP and CBD.

Mutations in alpha-synuclein (alpha S) and parkin cause heritable forms of Parkinson disease (PD). We hypothesized that neuronal parkin, a known E3 ubiquitin ligase, facilitates the formation of Lewy bodies (LBs), a pathological hallmark of PD. Here, we report that affinity-purified parkin antibodies labeled classical LBs in substantia nigra sections from four related human disorders: sporadic PD, inherited alphaS-linked PD, dementia with LBs (DLB), and LB-positive, parkin-linked PD. Anti-parkin antibodies also detected LBs in entorhinal and cingulate cortices from DLB brain and alphaS inclusions in sympathetic gangliocytes from sporadic PD. Double labeling with confocal microscopy of DLB midbrain sections revealed that approximately 90% of anti-alpha S-reactive LBs were also detected by a parkin antibody to amino acids 342 to 353. Accordingly, parkin proteins, including the 53-kd mature isoform, were present in affinity-isolated LBs from DLB cortex. Fluorescence resonance energy transfer and immunoelectron microscopy showed that alphaS and parkin co-localized within brainstem and cortical LBs. Biochemically, parkin appeared most enriched in cytosolic and postsynaptic fractions of adult rat brain, but also in purified, alpha S-rich presynaptic elements that additionally contained parkin's E2-binding partner, UbcH7. We conclude that parkin and UbcH7 are present with alphaS in subcellular compartments of normal brain and that parkin frequently co-localizes with alpha S aggregates in the characteristic LB inclusions of PD and DLB. These results suggest that functional parkin proteins may be required during LB formation.

Using alpha-synuclein-immunohistochemistry, 27 brains of dementia with Lewy bodies (DLB) were investigated to identify the progression of Lewy pathology including Lewy bodies (LB) and LB-related neurites in the cerebrum. The numbers of alpha-synuclein-positive LB and LB-related neurites were semiquantitatively evaluated in the amygdala, hippocampus, entorhinal cortex, transentorhinal cortex, insular cortex, middle temporal cortex and superior frontal cortex. The results indicated that Lewy pathology within the neuron progresses first in the axonal terminal, subsequently in the cell body and finally in the dendrite, that Lewy pathology in the cerebral cortex progresses first in layers V-VI, subsequently in layer III and finally in layer II, and that Lewy pathology in the cerebrum progresses first in the amygdala, subsequently in the limbic cortex and finally in the neocortex. In addition, Lewy pathology was graded from stage I to stage IV based on the progression of Lewy pathology. The 27 brains examined were classified into 3 brains showing stage I, 11 showing stage II, 7 showing stage III and 6 showing stage IV. Comparing these stages with the pathological subtypes of DLB brains, brains of the subtype showing severe Alzheimer pathology corresponded to brains showing an advanced stage, suggesting that Alzheimer pathology exacerbates Lewy pathology.

Alpha-synuclein is a major component of Lewy bodies (LB) in Parkinson's disease (PD) and dementia with LB (DLB), as well as of glial cytoplasmic inclusions (GCI) in multiple system atrophy (MSA). Recently, a novel protein called synphilin-1 has been identified that associates with alpha-synuclein, and it has been reported that co-transfection of both alpha-synuclein and synphilin-1 in mammalian cells yielded eosinophilic cytoplasmic inclusions resembling LB. Immunocytochemical and ultrastructural investigations have now been performed on the brain of patients with various neurodegenerative disorders using anti-synphilin-1 antibodies. These antibodies immunostained the neuropil in a punctate pattern throughout the brain of control subjects. In PD, most LB observed in the brain stem were positive for synphilin-1. These LB showed intense staining in their central cores, but their peripheral portions were only weakly stained or unstained. Pale bodies and Lewy neurites, which were positive for alpha-synuclein, were synphilin-1 negative. In DLB, a small fraction of cortical LB were immunolabeled by anti-synphilin-1. In MSA, numerous GCI were positive for synphilin-1. Immunoelectron microscopy revealed that the reaction product was localized within filamentous and circular structures in LB. Various neuronal and glial inclusions in neurodegenerative disorders other than LB disease and MSA were synphilin-1 negative. These findings suggest that abnormal accumulation of synphilin-1 is specific for brain lesions in which alpha-synuclein is a major component.

Parkinson's disease is a movement disorder characterized by degeneration of dopaminergic neurons in the substantia nigra pars compacta. Dopaminergic neuronal loss also occurs in Drosophila melanogaster upon directed expression of alpha-synuclein, a protein implicated in the pathogenesis of Parkinson's disease and a major component of proteinaceous Lewy bodies. We report that directed expression of the molecular chaperone Hsp70 prevented dopaminergic neuronal loss associated with alpha-synuclein in Drosophila and that interference with endogenous chaperone activity accelerated alpha-synuclein toxicity. Furthermore, Lewy bodies in human postmortem tissue immunostained for molecular chaperones, also suggesting that chaperones may play a role in Parkinson's disease progression.