A Matrigel-based 3D construct of SH-SY5Y cells models the α-synuclein pathologies of Parkinson's disease

Parkinson's disease (PD) is featured with α-synuclein-based Lewy body pathology, which however was difficult to observe in conventional two-dimensional (2D) cell culture and even in animal models. We herein aimed to develop a three-dimensional (3D) cellular model of PD to recapitulate the α-synuclein pathologies. All-trans-retinoic acid-differentiated human SH-SY5Y cells and Matrigel were optimized for 3D construction. The 3D cultured cells displayed higher tyrosine hydroxylase expression and improved dopaminergic-like phenotypes than 2D cells as suggested by RNA-sequencing analyses. Multiple forms of α-synuclein, including monomer, low and high molecular weight oligomers, were differentially present in the 2D and 3D cells, but mostly remained unchanged upon the MPP+ or rotenone treatment. Phosphorylated α-synuclein was accumulated and detergent-insoluble α-synuclein fraction was observed in the neurotoxin-treated 3D cells. Importantly, Lewy body-like inclusions were captured in the 3D system, including proteinase K-resistant α-synuclein aggregates, ubiquitin aggregation, β-amyloid and β-sheet protein deposition. The study provides a unique and convenient 3D model of PD which recapitulates critical α-synuclein pathologies and should be useful in multiple PD-associated applications.

Case Report: Concomitant Alzheimer's and Lewy-Related Pathology Extending the Spectrum of Underlying Pathologies of Corticobasal Syndrome

Corticobasal syndrome (CBS) is clinically characterized by progressive asymmetric rigidity and apraxia together with symptoms suggestive of cortical involvement and basal ganglia dysfunction. The spectrum of neurodegenerative diseases that can manifest with CBS is wide. The associations of CBS with corticobasal degeneration, progressive supranuclear palsy, Alzheimer's disease, frontotemporal lobar degenerations, Creutzfeldt–Jakob disease, or diffuse Lewy body pathology have been reported. We describe the case of a 71-year-old woman with CBS. The histopathological examination of brain tissue revealed concomitant pathology corresponding to the limbic stage of Lewy-related pathology and the intermediate stage of Alzheimer's-type pathology. To date, there have been only a few cases with a similar combination of pathology manifesting with the CBS phenotype that have been described in the literature. The extent and distribution of pathological changes in these cases were somewhat different from ours, and significance for clinical manifestation was attributed to only one of these pathologies. In our case, we assume that both types of pathology contributed to the development of the disease, considering the presumed specific spread of both types of pathological processes according to Braak's staging. Our case expands the spectrum of neurodegenerative pathological processes that may manifest with the typical CBS phenotype. Also, it points out the importance of identifying specific biomarkers that would enable more accurate in vivo differential diagnosis and more accurate determination of the underlying pathological processes of these diseases.

Epigenome-wide association study of human frontal cortex identifies differential methylation in Lewy body pathology

Parkinson’s disease (PD) and dementia with Lewy bodies (DLB) are closely related progressive disorders with no available causal therapy, neuropathologically characterized by intraneuronal aggregates of misfolded α-synuclein. To explore the role of DNA methylation changes in PD and DLB pathogenesis, we performed an epigenome-wide association study (EWAS) of 322 postmortem frontal cortex samples and replicated results in an independent set of 219 donors. We report novel differentially methylated replicating loci associated with Braak Lewy body stage near SFMBT2, PHYHIP, BRF1/PACS2 and DGKG. The DGKG locus also showed evidence of DNA methylation changes in the earliest, preclinical stage of disease. Differentially methylated probes were independent of known PD genetic risk alleles. Meta-analysis provided suggestive evidence for a differentially methylated locus within the chromosomal region affected by the PD-associated 22q11.2 deletion. Our findings elucidate novel disease pathways in PD and DLB and generate hypotheses for future molecular studies of Lewy body pathology.

Elderly-Onset Multiple System Atrophy with Lewy Body Pathology: A Case Report

An 81-year-old woman presented with a 2-year history of progressive dysarthria and gait disturbance. Subsequently, she developed orthostatic hypotension, obstructive sleep apnea, right-sided resting tremor, and rigidity. Together with characteristic findings of imaging studies, she was diagnosed with multiple system atrophy (MSA). Despite progressive dysphagia and repeated choking episodes, the patient elected not to use artificial feeding or tracheostomy. She died suddenly at age 91 after 12 years of illness. The autopsy revealed neuropathological features of both MSA and of Parkinson’s disease. The peripheral autonomic ganglia revealed both pre- and postganglionic involvement by synucleinopathy, which may have underscored the sudden death of the patient. The patient survived 10 years after onset, despite the presence of multiple poor prognostic factors in MSA including the onset of old age and early appearance of orthostatic hypotension and falls, in addition to the complication of PD pathology found by autopsy. Multidisciplinary team approach and her preserved cognitive function may have been contributory to the long-term survival.

Susceptibility to postmortem (co)-pathologies in antemortem atrophy-based subtypes of Alzheimer’s disease

ObjectivesTo investigate whether antemortem atrophy-based subtypes of Alzheimer’s disease (AD) may be differentially susceptible to individual or concomitance of AD and non-AD (co)-pathologies, assessed neuropathologically at postmortem.MethodsWe selected 31 individuals from the AD neuroimaging initiative with: an antemortem magnetic resonance imaging scan evaluating brain atrophy available within two years before death; an antemortem diagnosis of AD dementia or prodromal AD; and postmortem neuropathological confirmation of AD. Antemortem atrophy-based subtypes was modeled as a continuous phenomenon in terms of two recently proposed dimensions: typicality (ranging from limbic-predominant AD to hippocampal-sparing AD subtypes) and severity (ranging from typical AD to minimal atrophy AD subtypes). Postmortem neuropathological evaluation included global and regional outcomes: AD hallmark pathologies of amyloid-beta and tau; non-AD co-pathologies of alpha-synuclein Lewy body and TDP-43; and the overall concomitance across these four (co)-pathologies. Partial correlation and linear regression models were used to assess the association between antemortem atrophy-based subtypes and postmortem neuropathological outcomes.ResultsWe observed significant global and regional associations between antemortem typicality and postmortem (co)-pathologies including tau, alpha-synuclein Lewy bodies and TDP-43. Antemortem typicality demonstrated stronger regional associations with concomitance of multiple postmortem (co)-pathologies in comparison to antemortem severity. Our findings suggest the following susceptibilities of atrophy-based subtypes: limbic-predominant AD towards higher burden of tau and TDP-43 pathologies while hippocampal-sparing AD towards lower burdens; limbic-predominant AD and typical AD towards higher burden of alpha-synuclein Lewy body pathology while hippocampal-sparing AD and minimal-atrophy AD towards lower burdens.DiscussionThrough a direct antemortem-to-postmortem validation, our study highlights the importance of understanding heterogeneity in AD in relation to concomitance of AD and non-AD pathologies. Our findings provide a deeper understanding of both global and regional vulnerabilities of the biological subtypes of AD brain towards (co)-pathologies. Relative involvement of both AD hallmark and non-AD (co)-pathologies will enhance prevailing knowledge of biological heterogeneity in AD and could thus, contribute towards tracking disease progression and designing clinical trials in the future.

Association of Amyloid-β Pathology with Decision Making and Scam Susceptibility

Background: Recent findings suggest that poor decision making and increased scam susceptibility are harbingers of Alzheimer’s disease (AD) dementia and may be among the earliest behavioral manifestations of pathologic cognitive aging. However, the degree to which poor decision making and scam susceptibility reflect accumulating Alzheimer’s disease (AD) pathology remains unclear. Objective: To investigate the associations of AD pathology with decision making and scam susceptibility in older adults without dementia. Methods: Data came from 198 deceased participants without clinical dementia (mean age at death = 90 years; 69%women) from two ongoing studies of aging. All underwent annual clinical evaluations, completed assessments of healthcare and financial decision making and scam susceptibility, and brain donation. Neuropathologic evaluations quantified pathologic hallmarks of AD, amyloid-β and tau-tangles, Lewy body pathology, and TDP-43 proteinopathy. Results: In linear regression models adjusted for demographics, amyloid-β pathology was associated with lower decision making (estimate = –0.35; SE = 0.16, p = 0.03), particularly healthcare decision making (estimate = –0.20; SE = 0.09, p = 0.03), as well as greater scam susceptibility (estimate = 0.12; SE = 0.04, p = 0.003); tau-tangle pathology was not related. Further, TDP-43 pathology was associated with greater scam susceptibility (estimate = 0.10; SE = 0.04; p = 0.02). Conclusion: Accumulating AD pathology, particularly amyloid-β, is associated with poor decision making and increased scam susceptibility among older persons without overt cognitive impairment. These findings provide compelling evidence that decision making and scam susceptibility are sensitive to the earliest pathological changes of AD.

Cortical alpha-synuclein preformed fibrils do not affect interval timing in mice

One hallmark feature of Parkinsons disease (PD) is Lewy body pathology associated with misfolded alpha-synuclein. Previous studies have shown that striatal injection of alpha-synuclein preformed fibrils (PFF) can induce misfolding and aggregation of native alpha-synuclein in a prion-like manner, leading to cell death and motor dysfunction in mouse models. Here, we tested whether alpha-synuclein PFFs injected into the medial prefrontal cortex results in cognitive deficits in mouse models as measured by interval timing, which is reliably disrupted in PD patients and in rodent models. We injected human alpha-synuclein PFF or monomers in the medial prefrontal cortex pre-injected with adeno-associated virus (AAV) overexpressing human alpha-synuclein. Despite notable medial prefrontal cortical synucleinopathy, we did not observe consistent deficits in fixed-interval timing. These results suggest that cortical alpha-synuclein does not reliably disrupt interval timing in rodent models.