Alzheimer & Parkinson

The basal ganglia play a crucial role in action selection by facilitating desired movements and suppressing unwanted ones. The substantia nigra pars reticulata (SNr), a key output nucleus, facilitates movement through disinhibition of the superior colliculus (SC). However, its role in action suppression, particularly in primates, remains less clear. We investigated whether individual SNr neurons in three male macaque monkeys bidirectionally modulate their activity to both facilitate and suppress...

The aggregation of α-synuclein into amyloid fibrils is a hallmark of Parkinson's disease. This process has been shown to directly involve interactions between proteins and lipid surfaces when the latter are present. Despite this importance, the molecular mechanisms of lipid-induced amyloid aggregation have remained largely elusive. Here, we present a global kinetic model to describe lipid-induced amyloid aggregation of α-synuclein. Using this framework, we find that α-synuclein fibrils form via...

The Christchurch mutation (R136S) in the APOE3 (E3S/S) gene is associated with attenuated tau load and cognitive decline despite the presence of a causal PSEN1 mutation and high amyloid burden in the carrier. However, the molecular mechanisms enabling the E3S/S mutation to mitigate tau-induced neurodegeneration remain unclear. Here, we replaced mouse Apoe with wild-type human APOE3 or APOE3S/S on a tauopathy background. The R136S mutation decreased tau load and protected against tau-induced...

Neurodegenerative diseases activate innate and adaptive immune responses that can either slow or accelerate disease progression. Here, we sought to define beneficial immune pressures that emerge during tauopathy development in mice and humans. Using mice that express mutant human tau in neurons, we observed that microglia slowed tauopathy development by controlling the spread of phosphorylated tau (pTau) in the central nervous system and blood. However, over time microglia converted into...

Alzheimer's disease (AD) is a neurocognitive disorder that affects a significant part of the population. Its symptoms include progressive loss of memory and executive dysfunction. Genetic susceptibility to AD can be influenced by allele variants of the APOE gene. On the other hand, lifelong experiences such as educational attainment, occupational complexity, and leisure activities, known proxies for cognitive reserve (CR), may modulate gene expression, ultimately impacting AD susceptibility. In...

The decline of adult neurogenesis and neuronal function during aging underlies the onset and progression of neurodegenerative diseases such as Alzheimer's disease. Conventional therapies, including neurotransmitter modulators and antibodies targeting pathogenic proteins, offer only symptomatic improvement. As the most abundant glial cells in the brain, astrocytes outnumber neurons nearly fivefold. However, their proliferative and transdifferentiation potential renders them ideal candidates for...

Alzheimer's disease (AD) is the main cause of dementia in the old-age population worldwide. AD is a progressive brain neurodegenerative disease due to genetic and environmental factors that induce the accumulation of intracellular hyperphosphorylated tau protein and extracellular amyloid protein (Aβ). Particularly, cholinergic neurons in the prefrontal cortex and hippocampus are mainly affected in AD, resulting in cognitive impairment and memory dysfunction. Therefore, restoration of cholinergic...

Changes in the transcriptome are critical in shaping the structural plasticity of neurons, which underpins learning and long-term memory storage. Here, we explored the effect of two opposing, plasticity-associated pathways-cAMP second-messenger signaling and metabotropic glutamate receptor (mGluR1 and mGluR5) signaling-on the transcriptome in hippocampal neurons and how these pathways operate in distinct and coordinated manners to induce structural changes. Integration of transcriptome data and...

Striatal cholinergic interneurons (SCINs) exhibit pause responses conveying information about rewarding events, but the mechanisms underlying these pauses remain elusive. Thalamic inputs induce a pause mediated by intrinsic mechanisms and regulated by dopamine D2 receptors (D2Rs), though the underlying membrane currents remain unknown. Moreover, the role of D5 receptors (D5Rs) has not been addressed so far. Here, we performed ex vivo studies showing that glutamate released by thalamic inputs in...

Over 20% of patients with Alzheimer's disease (AD) worldwide are Chinese, although the efficacy of existing blood-based measures of AD biomarkers is largely unknown in Asian cohorts. Here we explored how plasma tau biomarkers correlated with cross-sectional and longitudinal AD-related outcomes and their diagnostic performance in 1,085 participants from three independent studies, including two Chinese cohorts, Greater-Bay-Area Healthy Aging Brain Study (n = 425) and Huashan (n = 297), and the...

In this issue of Neuron, Son et al.¹ reveal how pathologic α-synuclein inhibits autophagy, leading to neurodegeneration. Their work highlights the key roles of the acetyl-CoA-producing enzyme ACLY and aberrant cytoplasmic p300 acetylation, uncovering new therapeutic strategies for Parkinson's disease.

Clusterin (CLU) is a recognized genetic risk factor for Alzheimer's disease. In this issue of Neuron, Lish et al.¹ found that lower CLU levels in astrocytes, caused by the CLU risk allele, heightened inflammation and reduced synaptic functions, potentially increasing risk for cognitive decline.

Saliva is an accessible biofluid with potential for non-invasive disease diagnostics. This study explores how genetic susceptibility to common diseases is reflected in DNA methylation (DNAm) and gene expression profiles in saliva. We constructed cis-mQTL (n = 345) and cis-eQTL (n = 277) datasets and examined correlations between DNAm and gene expression. Saliva QTLs were integrated with summary statistics from 36 genome-wide association studies (GWAS) using Summary-based Mendelian Randomization...

Cortical tau deposition begins in higher-order association regions and spreads to lower-order primary sensory-motor networks in moderate/advanced Alzheimer's dementia. The neural mechanisms underlying this spatiotemporal pattern remain elusive. Initial evidence has shown that coupled dynamic, low-frequency (<0.1 Hz) brain activity in cerebrospinal fluid (CSF) flow and gray matter (global brain-CSF coupling) might be related to CSF clearance and thus β-amyloid accumulation. Here, we report that...

A polygenic score (PGS) for Alzheimer's disease (AD) was derived recently from data on genome-wide significant loci in European ancestry populations. We applied this PGS to populations in 17 European countries and observed a consistent association with the AD risk, age at onset and cerebrospinal fluid levels of AD biomarkers, independently of apolipoprotein E locus (APOE). This PGS was also associated with the AD risk in many other populations of diverse ancestries. A cross-ancestry polygenic...

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Mitochondria are essential for ATP production, calcium buffering, and apoptotic signaling, with mitophagy playing a critical role in removing dysfunctional mitochondria. This study demonstrates that PINK1-dependent mitophagy occurs more rapidly and is less spatially restricted in astrocytes compared to neurons. We identified hexokinase 2 (HK2) as a key regulator of mitophagy in astrocytes, forming a glucose-dependent complex with PINK1 in response to mitochondrial damage. Additionally, exposure...

The presence of α-synuclein (α-syn) aggregates, such as Lewy bodies in patients with Parkinson's disease (PD), contributes to dopaminergic cell death. Injection of PD patient-derived α-syn in nonhuman primates has illustrated the exquisite vulnerability of primate dopaminergic neurons. Here, we aimed to elucidate the temporal and spatial pathological changes induced by two distinct α-syn pathogenic structures, having large or small sizes. To unravel the underlying molecular pathways, we...

A scoping review of community health education studies for dementia prevention was conducted to clarify the form, content, outcome indicators, evaluation tools, and effects of community health education interventions for dementia prevention and to inform future research in this area. This scoping review of community-based health education interventions for Alzheimer's disease prevention across eight databases identified five intervention approaches-culturally adapted interventions, health...

Non-neuronal glial cells in the brain, such as astrocytes, play essential roles in maintaining the functional integrity of neuronal cells. A growing body of evidence suggests that cellular senescence of astrocytes, characterized by loss of proliferative potential and secretion of neurotoxic cytokines, makes significant contribution to neurotoxicity in Alzheimer's disease and a wide range of other neurodegenerative diseases. This review discusses the beneficial effects of Δ133p53α, a natural p53...