Alzheimer & Parkinson

Exercise's protective effects in Alzheimer's disease (AD) are well recognized, but cell-specific contributions to this phenomenon remain unclear. Here we used single-nucleus RNA sequencing (snRNA-seq) to dissect the response to exercise (free-wheel running) in the neurogenic stem-cell niche of the hippocampal dentate gyrus in male APP/PS1 transgenic AD model mice. Transcriptomic responses to exercise were distinct between wild-type and AD mice, and most prominent in immature neurons. Exercise...

Here, we explore the potential involvement of fumarate, a metabolite generated from the TCA cycle, as a key regulator of PINK1-Parkin-mediated mitophagy. Fumarate engages in a process called succination, forming S-(2-succino) cysteine with protein cysteine residues. Our research demonstrates that this modification specifically targets the sulfhydryl group of cysteine 323 and 451 residues of human Parkin, leading to the inhibition of its mitochondrial localization and E3 ligase activity, thereby...

Amyloid aggregates are pathological hallmarks of many human diseases, but how soluble proteins nucleate to form amyloids is poorly understood. Here, we use combinatorial mutagenesis, a kinetic selection assay, and machine learning to massively perturb the energetics of the nucleation reaction of amyloid-β (Aβ42), the protein that aggregates in Alzheimer's disease. In total, we measure the nucleation rates of >140,000 variants of Aβ42 to accurately quantify the changes in free energy of...

Alzheimer's disease (AD) and hearing loss (HL) are major age-related public health challenges with emerging evidence suggesting their interconnection. This study aimed to investigate global research trends, shared molecular mechanisms, and clinical implications of AD and HL. A total of 349 articles published between 2004 and 2024 were retrieved from the Web of Science Core Collection and analyzed using VOSviewer and CiteSpace. GeneCards and STRING databases were used to explore molecular targets...

Protein misfolding and conformational instability drive protein conformational disorders, causing either accelerated degradation and loss-of-function, as in inherited metabolic disorders like lysosomal storage disorders, or toxic aggregation and gain-of-function, as in neurodegenerative diseases like Alzheimer's disease or amyotrophic lateral sclerosis. Classical homocystinuria (HCU), an inborn error of sulfur amino acid metabolism, results from cystathionine beta-synthase (CBS) deficiency. CBS...

Neuronal injury is a common complication in patients with diabetes. These injuries include a wide range of neurobehavioral complications that significantly reduce the neuronal network efficiency and quality of life in affected individuals. Currently, diabetes-induced neuronal complications are a major global health challenge, and many studies have been performed to prevent or slow their progression. Semaglutide is a novel form of glucagon-like peptide-1 (GLP-1) agonist agents that has recently...

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Abnormal aggregation of amyloid-β protein (1-42) (Aβ(42)) is the primary pathology in Alzheimer's disease (AD). Two types of Aβ(42) fibrils have been identified in the insoluble fraction of diseased human brains. Here, we report that the fraction previously deemed 'soluble' during sarkosyl extraction of AD brains actually harbors numerous amyloid fibrils, with a looser bundling than those in the insoluble fraction. Using cryo-electron microscopy (cryo-EM), we discover a third type (type III) of...

During brain development, synapses are initially formed in excess and are later eliminated in an activity-dependent manner. Weak synapses are preferentially removed, but the mechanism linking neuronal activity to synapse removal is unclear. Here, we show that, in the developing mouse visual pathway, inhibiting synaptic transmission induces postsynaptic activation of caspase-3. Caspase-3 deficiency results in defects in synapse elimination driven by both spontaneous and experience-dependent...

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Accurate classification of neurodegenerative disorders remains a challenge in neuroscience. Using open-source electroencephalography (EEG) data, we investigated electrophysiological signatures to differentiate frontotemporal dementia (FTD) from Alzheimer's disease (AD) via complexity measures. Traditional relative band power analysis showed consistent increases in lower-frequency activity but did not distinguish the two disorders after correction. In contrast, fractal dimension and long-range...

Genome-wide association studies have identified many gene polymorphisms associated with an increased risk of developing late-onset Alzheimer's disease (LOAD). Many of these LOAD risk-associated alleles alter disease pathogenesis by influencing innate immune responses and lipid metabolism of microglia (MG). Here we show that boosting the expression of angiotensin-converting enzyme (ACE), a genome-wide association study LOAD risk-associated gene product, specifically in MG, reduces amyloid-β (Aβ)...

The β-N-methylamino-L-alanine (BMAA) is an emerging neurotoxin associated with human neurodegenerative diseases such as Alzheimer's disease. Here, we report the prevalence of BMAA synthesis in protein forms by marine diatoms and reconstruct its tentative biosynthesis pathway. Remarkably, the BMAA production is strongly induced by iron limitation. Transcriptomic analyses suggest that cysteine synthase (CysK) is involved in BMAA synthesis. This is verified as CRISPR/Cas9-based CysK knockout...

In this issue, Chadarevian et al. showed that engraftment of human iPSC-derived microglia (iMG) engineered to express secreted neprilysin (sNEP) under the plaque-responsive CD9 promoter reduces amyloid burden, neuronal damage, and inflammation in an Alzheimer's disease (AD) mouse model.¹ These findings establish a cell-based strategy to treat neurological diseases.

Parkinson's disease (PD), characterized by the selective loss of midbrain dopaminergic neurons (mDANs), is a promising target for cell replacement therapy. Two recent clinical trials¹^(,)² published in Nature report the safety and potential efficacy of human pluripotent stem cell-based approaches, representing a major milestone in regenerative medicine for PD.

N⁶-methyladenosine (m6A) is an abundant internal RNA modification that can impact gene expression at both post-transcriptional and transcriptional levels. However, the landscapes and functions of m6A in human brains and neurodegenerative diseases, including Alzheimer's disease (AD), are under-explored. Here, we examined RNA m6A methylome using total RNA-seq and meRIP-seq in middle frontal cortex of post-mortem brains from individuals with or without AD, which revealed m6A alteration on both...

Recent work leveraging artificial intelligence has offered promise to dissect disease heterogeneity by identifying complex intermediate brain phenotypes, called dimensional neuroimaging endophenotypes (DNEs). We advance the argument that these DNEs capture the degree of expression of respective neuroanatomical patterns measured, offering a dimensional neuroanatomical representation for studying disease heterogeneity and similarities of neurologic and neuropsychiatric diseases. We investigate the...

Disruption in neuronal and synaptic metabolic homeostasis is a key driver of neurodegeneration in Parkinson's disease (PD). Mitochondrial activity, biomass, and efficiency are critical to this balance. While activity and biomass are well characterized in PD pathology, mitochondrial metabolic efficiency remains insufficiently explored. Our previous studies showed that the protein product of PD-associated gene DJ-1 modulates metabolic efficiency through its interaction with the F1Fo-ATP-synthase β...

Duplication of the SNCA gene (SNCA^(Dupl)), linked to elevated levels of α-synuclein (aSyn), is a genetic cause of Parkinson's disease (PD). Our prior work with human-induced pluripotent stem cell (hiPSC)-derived midbrain neurons generated from patients with PD SNCA^(Dupl) identified neuritic deficits, accompanied by decreased levels of cytoskeletal element β-tubulin-III (bTubIII). To explore mechanisms underlying these effects in SNCA^(Dupl) neurons, we used CRISPR-Cas9 to generate isogenic...

The age-associated neurodegenerative disorder, Lewy body dementia (LBD), encompasses neuropsychiatric symptom-overlapping Dementia with Lewy bodies (DLB) and Parkinson's Disease with Dementia (PDD). We characterised how differential mitochondrial DNA (mtDNA) profiles contribute to neurotype-specific neurodegeneration and thereby clinicopathological heterogeneity, between LBD's syndromes. We further characterised key nuclear-encoding genes' recalibrations in response to such mtDNA changes. In...