Alzheimer & Parkinson

The aggregation of α-synuclein (αSyn), a 140-mer protein, has been implicated in the pathogenesis of Parkinson's disease, multiple system atrophy, and dementia with Lewy bodies. KTKEGV pseudo-repeats (KRs) in the sequence of αSyn are key mediators of its prion-like propagation and neurodegeneration. Despite the availability of symptomatic treatments, no current therapy effectively delays disease progression. Here we report a 77-nucleotide RNA aptamer called 1R6, obtained through in vitro...

Genomic studies at single-cell resolution have identified several cell types associated with clinical and pathological traits in Alzheimer's disease^(1-9), but have not examined associations that are shared across populations. To bridge this gap, here we use single-nucleus RNA sequencing and assay for transposase-accessible chromatin with sequencing to profile cortical and subcortical regions in post-mortem brain-tissue samples from Latin, white (excluding Latin) and African American (excluding...

While Alzheimer's disease (AD) is initiated by amyloid plaque accumulation, its progression involves local neuroinflammation that the brain cannot resolve when age-related dysfunction of the systemic immune system limits peripheral immune support. Preclinical studies using rodent models showed that transient systemic blockade of programmed death-ligand 1 is associated with reduced neuroinflammation, neuroprotection and attenuation of disease progression. Based on the underlying mechanism, a new...

Maximizing clinical benefits of therapeutics while minimizing adverse effects is a central challenge in drug development. For Parkinson's disease (PD), l-3,4-dihydroxyphenylalanine (l-dopa) is the most effective treatment available, but chronic use is associated with periods of reduced efficacy (motor fluctuations) and the debilitating on-target side effect of l-dopa-induced dyskinesia. To disentangle the molecular mechanisms underlying l-dopa's antiparkinsonian effects versus its dyskinetic...

The basal ganglia are characterized by somatotopic representation and are organized in parallel, functionally segregated corticostriatal circuits, but the impact of Parkinson's disease (PD) on this architecture is unknown. We mapped task-evoked dopamine release using [^(11)C]raclopride positron emission tomography/magnetic resonance in 13 early PD and 15 healthy control (HC) subjects during the performance of motor, cognitive, and reward tasks. In PD, motor tasks elicited decreased relative...

Inflammasomes, particularly the NLRP3 complex, play a central role in coordinating innate immune activation and neuroinflammatory responses within the cytosol. Persistent or dysregulated nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) activation promotes caspase-1-dependent maturation of interleukin (IL)-1β and IL-18 and triggers gasdermin D (GSDMD)-mediated pyroptosis, thereby contributing to the pathogenic cascades underlying Alzheimer's disease...

This longitudinal study including four independent cohorts assessed the spatiotemporal dynamics of tau extent and load changes in Alzheimer's disease using tau positron emission tomography data from 2,459 participants, including 898 followed for up to 7 years. Regional standardized uptake value ratios indexed tau load, whereas the spatial extent of tauopathy (SEOT) (proportion of abnormal voxels) measured tau extent. We observed burden-dependent longitudinal dynamics of tau progression: SEOT...

α-Synucleinopathies are devastating neurodegenerative diseases characterized by pathological accumulation of a neuronal protein, α-synuclein (αSyn). Lowering soluble αSyn levels is a promising therapeutic strategy to limit aggregation and neurotoxicity, but directly targeting this protein is hindered by its intrinsically disordered structure and other factors, such as its conformational heterogeneity and intracellular drug delivery barriers. Consequently, increasing attention has been directed...

Central to Alzheimer's disease pathology are prefibrillar oligomer assemblies of amyloid-β (Aβ) peptide. A widely discussed hypothesis proposes that amyloid-β oligomers insert into neuronal lipid membranes, disrupting their integrity and causing a loss of cellular homeostasis in Alzheimer's disease. This membrane disruption is believed to be a major source of Aβ-induced neurotoxicity. Cryo electron tomography (cryo-ET) has facilitated 3D nanoscale imaging of Aβ-membrane interactions under...

High levels of mitochondrial DNA (mtDNA) deletions have been described in the substantia nigra. However, the mechanisms involved are poorly understood. We found that transient expression of a mitochondrial targeted restriction endonuclease (mitoPstI) in mice leads to an accumulation of mtDNA rearrangements that involve both the PstI cleavage sites and unrelated specific regions of the mtDNA, including the MTERF1 binding site and the edge of the D-loop. This pattern of rearrangements after...

Alzheimer's disease (AD) is a multifactorial disorder involving various pathological mechanisms, such as amyloidosis, immune dysfunctions, and synaptic impairments, which are important therapeutic targets. Repurposing drugs to target these mechanisms offers a promising approach to reduce the costs and duration of drug development. Genetic studies underscore the critical role of microglial clearance of amyloid-beta (Aβ) in AD pathogenesis. Specifically, soluble ST2 (sST2)-one of the two major...

We present CIT-Lasso, a framework that uses only summary statistics to identify, genome-wide, sets of variants carrying non-redundant information on a phenotype, distinguishing likely causal variants from correlated variants that are merely associated. The open-source implementation completes genome-wide analysis in under 15 min on one CPU. In simulations, it outperforms existing methods in false discovery rate control, power, and fine-mapping resolution. Applied to an Alzheimer's disease...

Alzheimer's disease (AD) is a neurodegenerative disease characterized by progressive impairments in episodic and spatial memory, as well as circuit and network-level dysfunction. While functional impairments in medial entorhinal cortex (MEC) and hippocampus (HPC) have been observed in patients and rodent models of AD, it remains unclear how communication between these regions breaks down in disease, and what specific physiological changes are associated with the onset of memory impairment. Here,...

BACKGROUND: Latin America faces a high dementia burden, with increased prevalence of factors associated with cognitive decline. Multidomain lifestyle interventions might delay cognitive decline, but populations from Latin America remain under-represented in dementia prevention trials. We aimed to investigate the feasibility of a culturally adapted, multidomain, systematic lifestyle intervention and investigate its effects on global cognitive function in at-risk older adults (aged 60-77 years).

Astrocytes have traditionally been cast as supportive glia, but they are increasingly recognized as metabolic hubs that regulate cholesterol synthesis, fatty acid detoxification, lipid droplet dynamics and redox homeostasis in the CNS. Neurons have a limited intrinsic capacity for lipid storage and detoxification and rely heavily on astrocytes to maintain a safe lipid environment. Emerging evidence indicates that dysregulation of astrocytic lipid homeostasis precedes overt neuronal degeneration...

Alzheimer's disease (AD), a progressive neurodegenerative disorder characterized by brain atrophy and cognitive decline. While the amyloid cascade hypothesis remains the dominant framework, accumulating evidence indicates that mitochondrial dysfunction critically contributes to AD progression. Although improving mitochondrial function has been shown to rescue cognitive deficits in AD models, the underlying molecular mechanisms remain elusive. In this study, we identified a significant reduction...

LRRK2 (leucine-rich repeat kinase 2) and Parkin (PRKN) act in shared pathways and are implicated in Parkinson's disease (PD), leprosy, and other diseases. While leprosy likely imposed strong evolutionary pressure, PD's relatively late onset renders it largely invisible to natural selection. We examined the evolutionary history of LRRK2 and PRKN in primates and human populations and found evidence of positive selection on both genes, alongside strong constraint at LRRK2 disease-associated sites....

The aggregation of alpha-synuclein (aSyn) into intraneuronal inclusions of heterogeneous morphology, known as Lewy bodies (LBs), is a defining hallmark of Parkinson's disease (PD); yet, our understanding of the mechanisms underpinning their formation and heterogeneity remains incomplete. Here, we present a human isogenic induced pluripotent stem cell-derived dopaminergic neuron (iDA) model that faithfully recapitulates the diverse biochemical, morphological, and ultrastructural features of LB...

Mitochondria and inflammation are tightly linked in aging and Alzheimer's disease (AD), and recent evidence implicates mitochondrial double-stranded RNA (mt-dsRNA) as a potential trigger of inflammation. We examined mt-dsRNA accumulation and dsRNA signaling in brain aging and AD using complementary human brain tissue and in vitro transcriptomic datasets by quantifying mitochondrial transcripts, dsRNA editing, and related gene expression patterns. We found that mt-dsRNA signatures increased after...

Alzheimer's disease (AD) remains the leading cause of dementia worldwide and an escalating global health crisis. The hallmark amyloid plaques and neurofibrillary tangles (NFT) are now known to be accompanied by a complex array of pathologies that culminate in neurodegeneration and cognitive decline. New disease-modifying therapies for AD can now slow cognitive decline through the removal of amyloid plaques from the brain, but treatments to stop or prevent cognitive impairment remain elusive. In...