Alzheimer & Parkinson

The substantia nigra pars reticulata (SNr), a key basal ganglia output nucleus, is modulated by dopamine (DA) believed to be released locally from midbrain DA neurons. Although DA has been proposed to regulate γ-aminobutyric acid (GABA) release from medium spiny neuron (MSN) terminals via presynaptic D1 receptors, the precise mechanisms remain unclear. Using presynaptic optical recordings of synaptic vesicle fusion, calcium influx in D1-MSN synapses together with postsynaptic patch-clamp...

Decades of research on biomarker identification and integration in Alzheimer's disease (AD) have helped to advance biologically driven disease models, disease subtypes, and disease-modifying treatments. Key lessons learned from AD biomarker development include the need for integration of new biological insights, investment in large cross-sectional and longitudinal studies, a multicomponent biomarker approach, and recruitment of clinical trial cohorts and biosamples that are representative of the...

The nucleus basalis of Meynert (nbM), the major cholinergic output of the basal forebrain, regulates cortical modulation, learning, and memory. Dysfunction of the nbM-cortical cholinergic pathway is implicated in neurodegenerative and neurodevelopmental disorders, including Alzheimer's disease (AD) and Down syndrome (DS). Here, we generated human nbM organoids (hnbMOs) from human pluripotent stem cells (hPSCs) containing functional cholinergic projection neurons. Then we reconstructed...

The corpus callosum (CC) is the largest set of white matter fibers connecting the two hemispheres of the brain. In humans, it is essential for coordinating sensorimotor responses and performing associative or executive functions. Identifying which genetic variants underpin CC morphometry can provide molecular insights into the CC's role in mediating cognitive processes. We developed and used an artificial intelligence based tool to extract the midsagittal CC's total and regional area and...

Emerging clinical evidence suggests a link between environmental noise and the severity of Parkinson's disease (PD). However, the effects of high-decibel noise exposure on PD and its underlying mechanisms remain unclear. In this study, we demonstrate that acute noise exposure induces reversible motor deficits in subacute low-dose 6-hydroxydopamine (6-OHDA) mice, a model of presymptomatic early-stage PD, while chronic noise exposure results in irreversible motor deficits and significant loss of...

Alzheimer's disease (AD), the leading cause of dementia, could potentially be mitigated through early detection and interventions. However, it remains challenging to assess subtle cognitive changes in the early AD continuum. Computational modeling is a promising approach to explain a generative process underlying subtle behavioral changes with a number of putative variables. Nonetheless, internal models of the patient remain underexplored in AD. Determining the states of an internal model...

Ageing is a complex biological process driven, in part, by inflammaging. Recent research identifies the ectodysplasin A2 receptor (EDA2R) as a key regulator of inflammaging and a novel biomarker of ageing, with its expression increasing with age across diverse tissues in humans and animal models. Elevated EDA2R gene expression is associated with accelerated ageing, cellular senescence, frailty, obesity, acne, radiation response and increased levels of inflammatory, renal, cardiac and vascular...

Prevention of Alzheimer disease (AD) is a medical challenge owing to its complex pathogenesis, which involves amyloid-β (Aβ) and tau aggregation, neuroinflammation and progressive neurodegeneration. Development of disease-specific biomarkers has transformed our ability to detect AD pathology early, enabling more accurate diagnosis, monitoring and the development of targeted disease-modifying therapies. Consequently, primary and secondary prevention of AD have become feasible goals. In this...

No abstract

Physical inactivity is a recognized modifiable risk factor for Alzheimer's disease (AD), yet its relationship with progression of AD pathology in humans remains unclear, limiting the effective translation into prevention trials. Using pedometer-measured step counts in cognitively unimpaired older adults, we demonstrated an association between higher physical activity and slower cognitive and functional decline in individuals with elevated baseline amyloid. Importantly, this beneficial...

No abstract

Alzheimer neurodegenerative disease (AD) has had a major impact worldwide, with no effective drugs for treatment. We discovered and reported earlier that neurotrophic factor-α1 (NF-α1)/carboxypeptidase E (CPE) reversed neurodegeneration and cognitive dysfunction in AD mouse models. We then predicted computationally and validated experimentally that CPE interacts with a pharmacophore of six residues on the 5-HT1E receptor (HTR1E) to activate the ERK-BCL2 signaling pathway leading to protection of...

No abstract

Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder. In AD, there is a gradual impairment of memory and cognitive function that interferes with daily living. The pathophysiology of AD revolves around complex interactions between amyloid-β (Aβ) overproduction and accumulation, followed by tau hyperphosphorylation, which together promote a cascade of neuronal dysfunction and degeneration. AD has two forms, sporadic and familial, with genetic variants such as triggering...

The biology of individual lipid species and their relevance in Alzheimer's disease (AD) remains incompletely understood. To explore the lipidomic biomarkers associated with cognition function and neuropathological changes in AD, we utilize non-targeted mass spectrometry on 316 post-mortem brains from participants in the Religious Orders Study (ROS) or Rush Memory and Aging Project (MAP) cohorts classified as control, asymptomatic AD (AAD), or symptomatic AD (SAD), and integrate the lipidomics...

The importance of astrocytes for Alzheimer's disease (AD) pathology is increasingly appreciated, yet the mechanisms whereby this cell type impacts neurodegenerative processes remain elusive. Here we show that, in a genetic mouse model with diminished astrocyte stress response, even low levels of amyloid-β trigger astrocyte reactivity, resulting in brain inflammation and massive amyloid and tau pathologies. This dysfunctional response of astrocytes to amyloid-β acts through activation of δ...

Cerebral small vessel disease (SVD) is frequently comorbid with Alzheimer's disease (AD), and brain endothelial cells (BECs) express genes associated with AD genetic risk. However, the epigenome of neurovascular cells and its intersection with genetic risk remain unexplored. Here, we generated gene regulomes for human BECs, mural cells, and other brain cell types and showed that AD heritability is primarily immune related, with a modest BEC enrichment. On the other hand, SVD heritability is...

Parkinson's disease (PD) is the second most common neurodegenerative disorder. Mutations in human leucine-rich repeat kinase 2 (LRRK2), a multi-domain protein containing both a kinase and a GTPase, are a leading cause of the familial form of PD. Pathogenic LRRK2 mutations increase LRRK2 kinase activity. While the bulk of LRRK2 is found in the cytosol, the protein associates with membranes where its Rab GTPase substrates are found, and under certain conditions, with microtubules. Integrative...

Protocols for deriving midbrain dopaminergic (mDA) neurons for Parkinson's disease (PD) modeling and therapy remain incompletely benchmarked against in vivo references. To establish transcriptomic standards, we generated an integrated human fetal whole-brain atlas and a midbrain subatlas. Whole-brain analysis revealed strong region-specific signatures, underscoring the need for global mapping before refined midbrain annotation. We implemented this two-tier strategy, BrainSTEM (Brain Single-cell...

Genetic regulation of alternative splicing constitutes an important link between genetic variation and disease. Nonetheless, RNA splicing is regulated by both cis-acting elements and trans-acting splicing factors. Determining splicing events that are directed primarily by the cis- or trans-acting mechanisms will greatly inform our understanding of the genetic basis of disease. Here, we show that long-read RNA-seq, combined with our new method isoLASER, enables a clear segregation of cis- and...