Alzheimer & Parkinson

Electroencephalography (EEG) slowing and reduced functional connectivity are markers of Alzheimer's disease (AD) and Lewy body dementia (DLB), but the significance of epileptiform discharges to these changes remains unknown. To investigate whether epileptiform discharges are associated with EEG slowing or decreased functional connectivity over time. In this longitudinal observational exploratory study, we included a total of 15 healthy controls, 25 patients with AD, and 10 patients with DLB. The...

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by memory loss and behavioral changes. A pivotal influence on AD pathology is the dysregulation of microglia in the brain. Despite promising findings in mouse models, there are limitations to the translatable biological information across species due to differences in the physiology, timeline of disease, and human heterogeneity. To address these interspecies discrepancies, we developed a novel implementation of the...

All animals age. However, aging is a heterogeneous process, and individual organisms age differently. Moreover, within the same organism, cells or organs do not age at the same speed. For instance, neurodegeneration, a hallmark of aging, generally manifests later than other peripheral aging signs. The genetic determinants of aging are not completely understood. Gain-of-function (GoF) mutations in leucine-rich repeat kinase 2 (LRRK2^(GoF)) are major genetic risk factors for Parkinson's disease...

The subthalamic nucleus (STN) is a prominent target for deep-brain stimulation (DBS) in the treatment of levodopa-induced dyskinesia (LID), a common motor complication of Parkinson's disease. However, the precise impact of STN-DBS on LID remains unclear. Here, we investigated the functional roles of two distinct neuronal populations within the STN in regulating LID. In a mouse model of LID, STN neurons projecting to the entopeduncular nucleus (EP) exhibited a U-shaped activation pattern, whereas...

A paradoxical inverse correlation between cancer and Alzheimer’s disease has been repeatedly observed in epidemiological studies. While cancer and Alzheimer’s disease share common risk factors, most notably aging, the risk of Alzheimer’s disease in patients with cancer is significantly reduced, and the risk of cancer in patients with Alzheimer’s disease is halved. The convergence of two distinct disciplines, cancer and Alzheimer’s disease, offers an exciting and untapped opportunity to generate...

Perturbations in lysosome integrity are tightly linked to neurological disorders and ageing, but the underlying pathogenic mechanisms are incompletely understood. Using an unbiased proteomic approach, we here identified the bridge-like lipid transport protein VPS13C/PARK23 as a key component of a global early response pathway to lysosome damage. VPS13C readily binds lysosomes under mechanical or osmotic tension in anticipation of membrane lesions. The latter trigger a conformational change in...

Amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and Alzheimer's disease (AD) represent two major categories of neurodegenerative disorders-TAR DNA-binding protein 43 (TDP-43) and tau proteinopathies-for which the mechanisms driving neuronal death remain unclear. Single-cell whole-genome sequencing of 469 neurons from C9ORF72 ALS, C9ORF72 FTD, AD, and control brains revealed increased somatic single-nucleotide variants (sSNVs) and insertions/deletions (sIndels) in all three...

Type 2 diabetes (T2D) is traditionally viewed as a metabolic disease centered on insulin resistance and β-cell failure. However, growing evidence supports its reclassification as a systemic proteinopathy, in which the aggregation of amylin (islet amyloid polypeptide, IAPP) emerges as a key pathogenic event. In this review, we examine the shift toward an IAPP-centric model of disease, highlighting how IAPP misfolding and aggregation drive β-cell dysfunction independently of, and in parallel with,...

Alzheimer's disease and related dementia (ADRD) represents a growing public health burden, especially in low- and middle-income countries. Yet, most studies focus on Non-Hispanic white (NHW) populations from high-income countries. This study investigates plasma proteomic signatures associated with amyloid pathology in African populations. Nigerian older adults from the VALIANT study and participants from a Tanzanian study, with available biomarker quantification in plasma are employed. For...

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Detection of Alzheimer's disease (AD) before the development of clinical symptoms is critical for enabling the use of new treatments. Circular RNAs (circRNAs) are highly stable non-coding RNAs enriched in the brain that can cross the blood-brain barrier. Here, analyzing blood data from 1,221 individuals with AD and healthy individuals, we identified 34 circRNAs associated with AD status. A predictive model including these 34 circRNAs was comparable to plasma phosphorylated Tau-217 (pTau217) in...

Mutations in the GBA1 gene, which encodes the lysosomal glucocerebrosidase enzyme GCase, cause the lysosomal storage disorder Gaucher disease and represent the most common genetic risk factor for Parkinson's disease (PD). These mutations deplete lysosomal GCase activity and cause accumulation of GCase substrate, glucosylceramide, and its pathological metabolite, glucosylsphingosine. Impaired GCase activity then drives immune and neuronal dysfunction in Gaucher disease and promotes pathogenic...

The rapid expansion of plasma proteomic data and protein quantitative trait loci (pQTLs) provides an opportunity to identify genes that confer disease risk through their effect on plasma protein abundance. We conducted an Alzheimer's disease (AD) proteome-wide association study (PWAS) integrating publicly available plasma cis-pQTL data (1348 European American and 1385 African American genetically determined protein models) with AD dementia GWAS summary statistics. Whereas the African American...

Lateralization is a hallmark of brain organization, yet the structural basis underlying this phenomenon remains a critical, unresolved question in cognitive and systems neuroscience. In this study, we applied multivariate machine learning techniques to investigate variations of global brain asymmetry and their associations with cognitive functions, aging, and aging-related diseases, using large-scale datasets. Our findings revealed substantial and previously unknown structural differences...

Recent studies suggest that copy number variants (CNVs) may contribute to the missing heritability of complex diseases such as Alzheimer's disease (AD) and related dementias (ADRD). We performed a CNV analysis using genotyping data (Axiom 815 K Spanish biobank array) from the GR@ACE/DEGESCO dementia dataset (n = 20,067) of the Spanish population. Applying PennCNV and extensive quality control, 8275 controls and 7818 dementia cases were selected for gene-level case/control associations. We...

The gut microbiome is emerging as a modifier of risk for neurodegenerative diseases, but underlying mechanisms remain poorly understood. Here, we show that the hTau.P301S mouse model for progressive tauopathy develops alterations in the composition and function of the gut microbiome that are not recapitulated in amyloid-based 5xFAD or 3xTg models for Alzheimer's disease. Disrupting the gut microbiome via chronic antibiotic treatment exacerbates cognitive deficits and tau pathology in hTau.P301S...

Immunotherapy against amyloid β-protein (Aβ) for Alzheimer's disease (AD) has been widely approved. Breakthrough disease-modifying treatments such as lecanemab and donanemab are often followed by drugs with improved efficacy. By immunizing Trianni mice with aggregated synthetic Aβ, we obtained B28, a fully human antibody specifically selected for its neutralization of tau neuritic dystrophy induced by AD brain-derived oligomers. In a blinded trial in mutant human APP^(NL-G-F) knock-in mice,...

Prion diseases represent a unique biological paradigm with mechanistic parallels to other neurodegenerative conditions like Alzheimer's and Parkinson's diseases. However, the study of human prion pathobiology and the development of effective therapeutics has been severely constrained by the inability to propagate human prions in dividing cells-forcing reliance on costly and slow animal bioassays. Here, we report the generation of EKV cells-a humanized cell model which supports the robust,...

Tau pathology spreads cell to cell, but the mechanisms of intercellular tau transmission remain unclear. We find that the neuronal gene Arc is critical for the release of tau in neuronal extracellular vesicles (EVs) via a direct protein-protein interaction. Brain EVs purified from transgenic rTg4510 mutant tau mice (rTg^(WT)) crossed with Arc knockout mice (rTg^(Arc KO)) contain less tau and reduced tau seeding potential. Both Arc and tau are co-packaged in mouse and human brain-derived EVs....

Tau is an intrinsically disordered protein that functions to support cytoskeletal stability by binding microtubules in neuronal axons. While tau is involved in healthy neuronal function, it can become pathogenic by forming protein aggregates leading to neurologic diseases collectively known as tauopathies, which include Alzheimer's disease, frontotemporal dementia, and chronic traumatic encephalopathy. Post-translational modifications, including phosphorylation, glycosylation, acetylation,...