Synucleinopathies are human neurodegenerative diseases that include multiple system atrophy (MSA), Parkinson's disease, Parkinson's disease dementia (PDD) and dementia with Lewy bodies (DLB) (1). Existing treatments are at best symptomatic. These diseases are characterised by the presence in brain cells of filamentous inclusions of αsynuclein, the formation of which is believed to cause disease (2,3). However, the structures of α-synuclein filaments from human brain are not known. Here we show, using electron cryo-microscopy, that α-synuclein inclusions from MSA are made of two types of filaments, each of which consists of two different protofilaments. Non-proteinaceous molecules are present at the protofilament interfaces. By two-dimensional class averaging, we show that α-synuclein filaments from the brains of patients with MSA and DLB are different, suggesting that distinct conformers (or strains) characterise synucleinopathies. As was the case of tau assemblies (4-9), the structures of α-synuclein filaments extracted from the brains of individuals with MSA differ from those formed in vitro using recombinant proteins, with implications for understanding the mechanisms of aggregate propagation and neurodegeneration in human brain. These findings have diagnostic and potential therapeutic relevance, .

Corticobasal degeneration (CBD) is a neurodegenerative tauopathy that is characterised by motor and cognitive disturbances ( 1 – 3 ). A higher frequency of the H1 haplotype of MAPT , the tau gene, is present in cases of CBD than in controls ( 4 , 5 ) and genome-wide association studies have identified additional risk factors ( 6 ). By histology, astrocytic plaques are diagnostic of CBD ( 7 , 8 ), as are detergent-insoluble tau fragments of 37 kDa by SDS-PAGE ( 9 ). Like progressive supranuclear palsy (PSP), globular glial tauopathy (GGT) and argyrophilic grain disease (AGD) ( 10 ), CBD is characterised by abundant filamentous tau inclusions that are made of isoforms with four microtubule-binding repeats (4R) ( 11 – 15 ). This distinguishes 4R tauopathies from Pick’s disease, filaments of which are made of three-repeat (3R) tau isoforms, and from Alzheimer’s disease and chronic traumatic encephalopathy (CTE), where both 3R and 4R tau isoforms are found in the filaments ( 16 ). Here we report the structures of tau filaments extracted from the brains of three individuals with CBD using electron cryo-microscopy (cryo-EM). They were identical between cases, but distinct from those of Alzheimer’s disease, Pick’s disease and CTE ( 17 – 19 ). The core of CBD filaments comprises residues K274-E380 of tau, spanning the last residue of R1, the whole of R2, R3 and R4, as well as 12 amino acids after R4. It adopts a novel four-layered fold, which encloses a large non-proteinaceous density. The latter is surrounded by the side chains of lysine residues 290 and 294 from R2 and 370 from the sequence after R4. CBD is the first 4R tauopathy with filaments of known structure.

Synucleinopathies are human neurodegenerative diseases that include multiple system atrophy (MSA), Parkinson’s disease, Parkinson’s disease dementia (PDD) and dementia with Lewy bodies (DLB) (1). Existing treatments are at best symptomatic. These diseases are characterised by the presence in brain cells of filamentous inclusions of α-synuclein, the formation of which is believed to cause disease (2, 3). However, the structures of α-synuclein filaments from human brain are not known. Here we show, using electron cryo-microscopy, that α-synuclein inclusions from MSA are made of two types of filaments, each of which consists of two different protofilaments. Non-proteinaceous molecules are present at the protofilament interfaces. By two-dimensional class averaging, we show that α-synuclein filaments from the brains of patients with MSA and DLB are different, suggesting that distinct conformers (or strains) characterise synucleinopathies. As was the case of tau assemblies (4–9), the structures of α-synuclein filaments extracted from the brains of individuals with MSA differ from those formed in vitro using recombinant proteins, with implications for understanding the mechanisms of aggregate propagation and neurodegeneration in human brain. These findings have diagnostic and potential therapeutic relevance, especially in view of the unmet clinical need to be able to image filamentous α-synuclein inclusions in human brain.

Cryo-EM of seeded alpha-synuclein filaments S. L€ ovestam et al.

Lewy body disease (LBD) is a spectrum of progressive neurodegenerative disorders characterized by the wide distribution of Lewy bodies and neurites in the central and peripheral nervous system (CNS, PNS). Clinical diagnoses include Parkinson’s disease (PD), dementia with Lewy bodies, or pure autonomic failure. All types of LBD are accompanied by non-motor symptoms (NMSs) including gastrointestinal dysfunctions such as constipation. Its relationship to Lewy body-related α-synucleinopathy (Lewy pathology) of the enteric nervous system (ENS) is attracting attention because it can precede the motor symptoms. To clarify the role of ENS Lewy pathology in disease progression, we performed a clinicopathological study using the Brain Bank for Aging Research in Japan. Five-hundred and eighteen cases were enrolled in the study. Lewy pathology of the CNS and PNS, including the lower esophagus as a representative of the ENS, was examined via autopsy findings. Results showed that one-third of older people (178 cases, 34%) exhibited Lewy pathology, of which 78 cases (43.8%) exhibited the pathology in the esophagus. In the esophageal wall, Auerbach’s plexus (41.6%) was most susceptible to the pathology, followed by the adventitia (33.1%) and Meissner’s plexus (14.6%). Lewy pathology of the esophagus was significantly associated with autonomic failures such as constipation (p < 0.0001) and among PNS regions, correlated the most with LBD progression (r = 0.95, p < 0.05). These findings suggest that the propagation of esophageal Lewy pathology is a predictive factor of LBD.

Tauopathies are the most common type of neurodegenerative proteinopathy, being characterized by cytoplasmic aggregates of hyperphosphorylated tau protein. The formation and morphologies of these tau inclusions, the distribution of the lesions and related metabolic changes in cytoplasm differ among different tauopathies. The aim of this study was to examine whether there are differences in the post-translational modifications (PTMs) in the pathological tau proteins. We analyzed sarkosyl-insoluble pathological tau proteins prepared from brains of patients with Alzheimer’s disease, Pick’s disease, progressive supranuclear palsy, corticobasal degeneration, globular glial tauopathy, and frontotemporal dementia and parkinsonisms linked to chromosome 17 with tau inclusions using liquid chromatography mass spectrometry. In pathological tau proteins associated with a wide range of tauopathies, 170 PTMs in total were identified including new PTMs. Among them, common PTMs were localized in the N- and C-terminal flanking regions of the microtubule binding repeats and PTMs, which were considered to be disease-specific, were found in microtubule binding repeats forming filament core. These suggested that the differences in PTMs reflected the differences in tau filament core structures in each disease.

BackgroundGranulovacuolar degeneration (GVD) is one of the pathological hallmarks of Alzheimer's disease (AD), and it is defined as electron-dense granules within double membrane-bound cytoplasmic vacuoles. Several lines of evidence have suggested that GVDs appear within hippocampal pyramidal neurons in AD when phosphorylated tau begins to aggregate into early-stage neurofibrillary tangles. The aim of this study is to investigate the association of GVDs with phosphorylated tau pathology to determine whether GVDs and phosphorylated tau coexist among different non-AD neurodegenerative disorders.MethodsAn autopsied series of 28 patients with a variety of neurodegenerative disorders and 9 control patients were evaluated. Standard histological stains along with immunohistochemistry using protein markers for GVD and confocal microscopy were utilized.ResultsThe number of neurons with GVDs significantly increased with the level of phosphorylated tau accumulation in the hippocampal regions in non-AD neurodegenerative disorders. At the cellular level, diffuse staining for phosphorylated tau was detected in neurons with GVDs.ConclusionsOur data suggest that GVDs appear in relation to hippocampal phosphorylated tau accumulation in various neurodegenerative disorders, while the presence of phosphorylated tau in GVD-harbouring neurons in non-AD neurodegenerative disorders was indistinguishable from age-related accumulation of phosphorylated tau. Although GVDs in non-AD neurodegenerative disorders have not been studied thoroughly, our results suggest that they are not incidental findings, but rather they appear in relation to phosphorylated tau accumulation, further highlighting the role of GVD in the process of phosphorylated tau accumulation.

Corticobasal degeneration (CBD) is a neurodegenerative tauopathy that is characterised by motor and cognitive disturbances (1-3). A higher frequency of theH1 haplotype of MAPT, the tau gene, is present in cases of CBD than in controls (4,5) and genome-wide association studies have identified additional risk factors (6). By histology, astrocytic plaques are diagnostic of CBD (7,8), as are detergentinsoluble tau fragments of 37 kDa by SDS-PAGE (9). Like progressive supranuclear palsy (PSP), globular glial tauopathy (GGT) and argyrophilic grain disease (AGD) (10), CBD is characterised by abundant filamentous tau inclusions that are made of isoforms with four microtubule-binding repeats (4R) (11-15). This distinguishes 4R tauopathies from Pick's disease, filaments of which are made of threerepeat (3R) tau isoforms, and from Alzheimer's disease and chronic traumatic encephalopathy (CTE), where both 3R and 4R tau isoforms are found in the filaments (16). Here we report the structures of tau filaments extracted from the brains of three individuals with CBD using electron cryomicroscopy (cryo-EM). They were identical between cases, but distinct from those of Alzheimer's disease, Pick's disease and CTE (17-19). The core of CBD filaments comprises residues K274-E380 of tau, spanning the last residue of R1, the whole of R2, R3 and R4, as well as 12 amino acids after 3 R4. It adopts a novel four-layered fold, which encloses a large non-proteinaceous density. The latter is surrounded by the side chains of lysine residues 290 and 294 from R2 and 370 from the sequence after R4. CBD is the first 4R tauopathy with filaments of known structure.We extracted tau filaments from the frontal cortex of three individuals with a neuropathologically confirmed diagnosis of CBD.Abundant neuronal inclusions and astrocytic plaques were stained by antibodies specific for 4R tau (Figure 1a-c) and for hyperphosphorylated tau (Figure 1e), as well as by Gallyas-Braak silver (Figure 1f). Antibodies against 3R tau failed to give specific staining (Figure 1d). By immunoblotting of sarkosyl-insoluble fractions, two major tau bands of 64 and 68 kDa were stained by an antibody specific for 4R tau, as were two minor bands of 37 kDa ( Figure 1g). Immunogold negative-stain EM with antibodies specific for the N-and C-termini of tau, as well as for R1, R2, R3 and R4, indicated that epitopes of R2, R3 and R4 form part of the ordered cores of filaments in all three cases of CBD (Extended Data Figure 1). This is consistent with the estimated lengths of trypsin-resistant cores of CBD filaments (20). Narrow and wide filaments were present (Figure 1h), in agreement with previous findings (21). Narrow filaments have a helical twist with a crossover distance of approximately 900 Å and a minimal width of 80 Å, a maximal width of 130 Å. Wide filaments have a crossover distance of donating brain tissues; F. Epperson, R.M. Richardson and U. Kuederli for brain collection and technical support with neuropathology; G. Cannone, S. Chen, J. Brown, G. Sharov, and A. Yeates f...