Alzheimer & Parkinson

The nicotinamide adenine dinucleotide (NAD^(+)) hydrolase sterile alpha and Toll/interleukin-1 receptor motif-containing 1 (SARM1) is the central executioner of pathological axon degeneration and is allosterically activated by an increased nicotinamide mononucleotide (NMN)/NAD^(+) ratio. DNA damage induces NAD^(+) loss and an increased NMN/NAD^(+) ratio by hyperactivating poly(ADP-ribose) polymerase 1 (PARP1), which triggers the parthanatos cell death pathway. Multiple mechanistically distinct...

PINK1/Parkin-mediated mitophagy and other related mitochondrial quality control pathways are critical to maintaining cellular homeostasis and neuronal health, and indeed, mutations in PINK1 and PRKN that disrupt this pathway cause early-onset Parkinson's disease. While PINK1-dependent Parkin recruitment to damaged mitochondria has been established for over a decade, recent structural and biochemical advances have illuminated the mechanisms governing their allosteric activation and integration...

Alzheimer's disease (AD) is a major cause of dementia and cognitive decline. Here, we assessed how episodic memory (EM) network dysfunction, a hallmark of AD, is related to the longitudinal progression of AD biomarkers, neurodegeneration and cognition using data from the DZNE DELCODE study. This data set includes over 1000 longitudinal functional magnetic resonance imaging measurements of EM network function. We related activation and deactivation of EM to individual disease progression scores...

Gaining precise control of gene expression is crucial in biomedical applications. However, spatiotemporal precision remains challenging. Here, we present a remotely controlled in vivo gene switch responsive to electromagnetic fields (EMFs) that enables precise spatiotemporal activation of target genes. We uncovered the EMF-inducible gene switch activation mechanism via a CRISPR-Cas9 screen, identifying cytochrome b5 type B (Cyb5b) as an essential mediator likely acting as an EMF sensor. The...

Multiple system atrophy (MSA) is a rare, age-related neurodegenerative disease that shares clinical and pathological features with Parkinson's disease (PD) but presents a more devastating disease course. To elucidate the distinct cellular pathophysiology, we performed single-nucleus RNA sequencing on postmortem striatal brain tissue from 7 MSA and 12 PD patients, and 10 non-neurological cases. Here, we show significant compositional differences in astroglia and microglia subtypes, while...

Dissecting biological pathways highlighted by Mendelian gene discovery has provided critical insights into the pathogenesis of Parkinson's disease (PD) and neurodegeneration. This approach ultimately catalyzes the identification of potential biomarkers and therapeutic targets. Here we identify PSMF1 as a gene implicated in parkinsonism and childhood neurodegeneration. We find that biallelic PSMF1 missense and loss-of-function variants co-segregate with phenotypes from early-onset PD to perinatal...

Disruptions in the glymphatic system and its downstream meningeal lymphatic drainage pathway, crucial for brain waste clearance, are linked to the pathogenesis of Alzheimer's disease (AD), yet the underlying mechanisms remain unclear. Abnormal calcium dynamics in astrocytes represents an early event in the mouse models of AD. Here we show functional association between amyloid-β-induced elevation of Ca^(2+) dynamics in medial prefrontal cortex astrocytes and glymphatic dysfunction in cognitively...

Biomarkers to determine underlying frontotemporal lobar degeneration (FTLD) tau or TAR DNA-binding protein (TDP) pathology during life are needed to advance clinical trials targeting specific FTD pathologies. For this purpose, we developed a new ultrasensitive immunoassay to quantify acetylated tau at lysine 174 (AcTau174) in cerebrospinal fluid (CSF). In a sporadic cohort (n = 513), AcTau174 concentrations were higher in all dementia groups (FTLD-TDP, FTLD-Tau, Alzheimer's disease (AD), mild...

Plasma phosphorylated tau 217 (pTau217) is an excellent biomarker of Alzheimer's disease (AD) pathology, but it remains uncertain whether pTau217 can predict amyloid-β (Aβ) and tau accumulation prior to Aβ positron emission tomography (PET) positivity. Here, we leverage data from a well-characterized prospective cohort of cognitively unimpaired older adults to examine mass spectrometry-based plasma %pTau217 (pTau217/non-phosphorylated-Tau217×100) relative to changes in Aβ/tau PET and cognition....

Astrocytes are key partners for neurons and can impact diseases such as Alzheimer's disease (AD), as they exhibit multiple reactive changes. Recent single cell/nucleus genomics analyses evidence astrocyte subpopulations coexisting in normal and AD brains. However, the signaling cascades controlling them, their functional characteristics and roles in AD are still unknown. Here, thanks to astrocyte-specific reporters for STAT3 and NF-kB signaling pathways, two regulators of astrocyte reactivity,...

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Cellular senescence, a state of irreversible cell cycle arrest, plays a key role in neurodegenerative diseases, including Alzheimer's disease (AD). While senescent cells are emerging as potential therapeutic targets, the dynamics of their occurrence over time and the specific cell types most affected by AD are still not well understood. This study investigates age- and pathology-dependent changes in senescence markers, specifically p16, p21, and p53, using the amyloidogenic App^(NL-G-F) knock-in...

Nuclear speckles (NS) are membraneless nuclear organelles that act as critical hubs for pre-messenger RNA splicing. Defects in splicing are linked to several human diseases, including cancer, Alzheimer's disease, and dystrophies. While CLK kinases regulate the mobilization of splicing factors from NS, the molecular mechanisms underlying NS assembly and dissolution remain unclear. Using an adaptation of the Biotinylation by Antibody Recognition technique, we identified polyphosphate (polyP) as a...

Adult hippocampal neurogenesis declines with aging and in neurological disorders, leading to cognitive impairment. We previously showed that inducing Plagl2 and antagonizing Dyrk1a (iPaD) rejuvenates aged neural stem cells (NSCs), enhancing neurogenesis and cognition in aged mice. Here, we found that NSC-specific iPaD treatment activates neurogenesis, reduces amyloid-β deposition, and improves cognition in Alzheimer's disease model mice. Transcriptomic analysis revealed widespread changes in...

Combining allele-specific expression (ASE) analysis with single-cell RNA-seq can elucidate how genomic variation affects RNA expression at the single-cell level. We explore how experimental and computational choices impact the power of ASE-based methods and develop a suite of single-cell ASE computational tools. With single-nucleus RNA-Seq, we extract more ASE information from reads in intronic than exonic regions. We show how read length can increase power and that hybrid selection improves...

PINK1 serves as the central regulator of PINK1-PRKN-mediated mitophagy, and its precise regulation is critical for efficient mitochondrial clearance. Although the cleavage of PINK1 and its subsequent degradation via the N-end rule pathway under basal conditions are well understood, how full-length PINK1 stability is regulated following mitochondrial damage has remained elusive. In our recent study, we identified the STUB1-VCP/p97 axis as a mechanism that fine-tunes full-length PINK1 levels...

Glial crosstalk surrounding amyloid-β (Aβ) plaques establishes a self-propagating inflammatory niche fueling Alzheimer's disease (AD), yet the molecular triggers remain incompletely defined. We found that the calcium-dependent enzyme peptidyl-arginine deiminase 2 (PAD2) was selectively upregulated in plaque-associated astrocytes in human AD cortex and multiple APP AD transgenic mouse models. Astrocyte-specific deletion of Padi2 in 5×FAD mice rescued learning and memory, lowered Aβ load,...

One essential post-transcriptional regulatory mechanism that increases protein diversity in eukaryotes is alternative splicing. This process is crucial for maintaining nervous system function and is highly active in neurons. Dysregulation of alternative splicing is a common pathogenic factor in many neurodegenerative diseases. For example, splicing variants of tau protein and amyloid precursor protein are implicated in Alzheimer's disease; aberrant splicing of α-synuclein (SNCA) and upregulation...

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