Amyloid-beta aggregates induce vasculopathy via ferroptosis in brain endothelial cells
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE310780 | GEO | 2026/06/11
REPOSITORIES: GEO
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Project description:Alzheimer’s disease (AD), currently affecting millions of people worldwide, is the most prevalent form of dementia. Treatment strategies aiming to interfere with the formation of amyloid β (Aβ) plaques and neurofibrillary tangles (NFTs), the two major AD hallmarks, have shown modest or no effect. Recent evidence suggests that ferroptosis, a type of programmed cell death caused by iron accumulation and lipid peroxidation, contributes to AD pathogenesis. Here we evaluate if Aβ is associated with ferroptosis pathways and whether ferroptosis inhibition could attenuate Aβ-related effects. The existing link between ferroptosis and AD has been largely based on cell culture and animal studies, while evidence from human brain tissue is limited. Performing positive pixel density scoring on immunohistochemically stained post mortem BA17 sections revealed that the progression of AD pathology was accompanied by decreased expression of nuclear receptor co-activator 4 (NCOA4) and glutathione peroxidase 4 (GPX4) in the grey matter (GM). The expression of ferroportin, NCOA4, GPX4, 4-hydroxy-2-nonenal (4HNE) and cytochrome C was significantly lower, while the expression of ferritin was higher in the Aβ plaque area compared to the immediate vicinity of the non-Aβ tissue in AD brain tissue. Taken together, these findings indicate a relationship between Aβ-related processes and the expression of ferroptosis-related proteins. Additionally, ferroptosis inhibition prevented Aβ pathology, decreased lipid peroxidation and restored iron storage in human AD iPSCs-derived brain cortical organoids (cBOs). Differential expression analysis of AD organoids compared to isogenic controls indicate activation of the ferroptotic pathway. This further supports the previously suggested link between Aβ-related pathology and ferroptosis. Determining the causality between development of Aβ plaques and deregulation of molecular pathways involved in ferroptosis is crucial for developing potential therapeutic interventions.
2025-05-06 | PXD047941 | Pride
Project description:A prevalent view in treating age-dependent disorders including Alzheimer’s disease (AD) is that the underlying amyloid plaque pathology must be targeted for cognitive improvements. In contrast, we report here that repeated scanning ultrasound (SUS) treatment at 1 MHz frequency can ameliorate memory deficits in the APP23 mouse model of AD without reducing amyloid-β (Aβ) burden. Different from previous studies that had shown Aβ clearance as a consequence of blood-brain barrier (BBB) opening, here, the BBB was not opened as no microbubbles were used. Quantitative proteomics and functional magnetic resonance imaging revealed that ultrasound induced long-lasting functional changes that correlate with the improvement in memory. Intriguingly, the treatment was more effective at a higher frequency (1MHz) than at a frequency within the range currently explored in clinical trials in AD patients (286 kHz). Together, our data suggest frequency-dependent bio-effects of ultrasound and a dissociation of cognitive improvement and Aβ clearance, with important implications for the design of trials for AD therapies.
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Project description:Alzheimer’s disease (AD) is the leading cause of dementia affecting 55 million people worldwide. The pathological hallmarks of AD, beta-amyloid (Aβ) plaques and neurofibrillary tangles (NFT), follow distinct stereotypical patterns of progression across brain regions and trigger a multicellular response that ultimately leads to neuronal loss and cognitive decline. Despite the uniform spread of Aβ plaque across the cortex during AD progression, different regions demonstrate varying levels of vulnerability and resilience to temporal Aβ plaque induced changes, such as NFT accumulation. There is a critical gap in our understanding of the cell types and molecular mechanisms that underlie these region-specific differences in resilience to Aβ plaque induced changes. In this study, we hypothesized that brain region and cell type specific transcriptional responses within the Aβ microenvironment, and more broadly within the grey matter, may contribute to this variation. We carried out matched multi-region spatial transcriptomics and Aβ immunofluorescence staining from the entorhinal, occipito-temporal, dorsolateral prefrontal and striate cortices from two individuals with Braak III and Thal 4 AD. Spatiotemporal comparisons of cell type proportions, gene expression, and cell-cell communication revealed differences in the vulnerability of somatostatin and somatostatin chondrolectin inhibitory neurons and the expression of endosomal and lysosomal trafficking and metallothionein genes within the Aβ plaque microenvironment. We also observed variations in blood-brain-barrier dysfunction, fibroblast growth factor signaling, and vascular impairment and repair related cell-cell communication networks within the grey matter. Our results demonstrate the value of simultaneously profiling AD-omic and spatial modalities in multiple regions to elucidate how cortical region-specific differences contribute to selective vulnerability and resilience during neurodegeneration.
2026-01-14 | GSE304497 | GEO
Project description:With advances in single-cell genomics, molecular signatures of cells comprising the brain vasculature are revealed in unprecedented detail, yet the ageing-associated cell subtype transcriptomic changes which may contribute to neurovascular dysfunction in neurodegenerative diseases remain elusive. Here, we performed single-cell transcriptomic profiling of brain endothelial cells (EC) in young adult and aged mice to characterize their ageing-associated genome-wide expression changes. We identified zonation-dependent transcriptomic changes in aged brain EC subtypes, with capillary ECs exhibiting the most transcriptomic alterations. Pathway enrichment analysis revealed altered immune/cytokine signaling in ECs of all vascular segments, while functional changes impacting the blood-brain barrier (BBB) and glucose/energy metabolism were most prominently implicated in ECs of the capillary bed – the primary site where ECs and other neurovascular unit (NVU) cell types closely interact and coordinate to regulate BBB and cerebral blood flow in health and diseased conditions. Furthermore, an overrepresentation of Alzheimer’s disease (AD)-associated genes identified from GWAS studies was evident among the human orthologs of differentially expressed genes of aged capillary ECs but not other EC subtypes. Importantly, for numerous EC-enriched differentially expressed genes with important functional roles at the BBB and/or association with AD, we found concordant expression changes in human aged or AD brains. Finally, we demonstrated that treatment with exenatide, a glucagon-like peptide-1 receptor (GLP-1R) agonist, strongly reverses transcriptomic changes in ECs and largely reduces BBB leakage in the aged brain. Thus, our study revealed novel vascular ageing-associations of AD in the brain capillary endothelium, and provides insights into detailed transcriptomic alterations underlying brain EC ageing that are complex with subtype specificity yet amenable to pharmacological interventions.
2020-03-30 | GSE147693 | GEO
Project description:In Alzheimer’s disease (AD), sensome receptor dysfunction impairs microglial danger-associated molecular pattern (DAMP) clearance and exacerbates disease pathology. While extrinsic signals including interleukin-33 (IL-33) can restore microglial DAMP clearance, it remains largely unclear how the sensome receptor(s) is regulated and interacts with DAMP during phagocytic clearance. Here, we show that IL-33 induces VCAM1 in microglia, which promotes microglial chemotaxis toward amyloid-beta (Aβ) plaque-associated ApoE, and leads to Aβ clearance. We show that IL-33 stimulates a chemotactic state in microglia, characterized by Aβ-directed migration. Functional screening identified that VCAM1 directs microglial Aβ chemotaxis by sensing Aβ plaque-associated ApoE. Moreover, we found that disrupting VCAM1–ApoE interaction abolishes microglial Aβ chemotaxis, resulting in decreased microglial clearance of Aβ. In patients with AD, higher cerebrospinal fluid levels of soluble VCAM1 were correlated with impaired microglial Aβ chemotaxis. Together, our findings demonstrate that promoting VCAM1–ApoE-dependent microglial functions ameliorates AD pathology.
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Project description:Amyloid-beta (Aβ) deposition is an initiating factor in Alzheimer´s disease (AD). Microglia are the brain immune cells that surround and phagocytose Aβ, but their phagocytic capacity declines in AD. This is in agreement with studies that associate AD risk loci with genes regulating phagocytic function. Immunotherapies are currently pursued as therapeutic strategies against AD and there are increased efforts to understand the role of the immune system in ameliorating AD pathology. Here, we evaluated the effect of the Aβ targeting ACI-24 vaccine in preventing the AD pathology in an amyloidosis mouse model. ACI-24 vaccination elicited a robust and sustained antibody response in APPPS1 mice with an accompanying reduction of Aβ plaque load, amyloid plaque-associated ApoE and dystrophic neurites as compared to non-vaccinated controls. Furthermore, plaque-associated microglia had the tendency to be more activated post vaccination. The lower Aβ plaque load triggered by vaccination with ACI-24 was in concordance with the bulk transcriptomic analysis that revealed a reduction in the expression of several disease-associated microglial signatures. Accordingly, plaque-distant microglia displayed a more ramified morphology, supporting beneficial effects of the vaccination on bulk microglial phenotypes. Our study demonstrates that administration of the Aβ targeting vaccine, ACI-24, triggers protective microglial responses that translate into a reduction of AD pathology suggesting its use as a safe and cost effective AD therapeutic intervention.
2023-01-09 | PXD038665 | Pride
Project description:Endothelial cells (ECs) in cerebral vessels are considered the primary targets in acute hemorrhagic brain injuries. EC dysfunction can aggravate neuronal injuries by causing secondary inflammatory responses and blood-brain barrier (BBB) disruption. ECs comprising the BBB are known to have a higher mitochondrial volume compared with peripheral ECs. In previous study, we reported Tek-CRIF1-knockout (KO) mice, with EC-specific deletion of the mitochondrial OxPhos-related gene, Crif1, also known as Gadd45gip1 (encoding GADD45G-interacting protein 1), display profound BBB defects accompanied by reduced expression of junctional proteins in ECs. To identify signaling pathways involved in linking EC-specific mitochondrial dysfunction and BBB disruption, we first performed RNA sequencing using isolated cerebral vessels from Tek-CRIF1 mice. This transcriptome analyses of the Tek-CRIF1-KO mouse revealed significant changes in some signaling, a pathway intimately involved in BBB maintenance.
2022-08-31 | GSE207106 | GEO
Project description:Qosa2014 - Mechanistic modeling that
describes Aβ clearance across BBB
Qosa2014 - Mechanistic modeling that
describes Aβ clearance across BBB.
Encoded non-curated model. Issues:
- Confusing equation 6
- Missing initial values for spices
This model is described in the article:
Differences in amyloid-?
clearance across mouse and human blood-brain barrier models:
kinetic analysis and mechanistic modeling.
Qosa H, Abuasal BS, Romero IA,
Weksler B, Couraud PO, Keller JN, Kaddoumi A.
Neuropharmacology 2014 Apr; 79:
668-678
Abstract:
Alzheimer's disease (AD) has a characteristic hallmark of
amyloid-? (A?) accumulation in the brain. This accumulation of
A? has been related to its faulty cerebral clearance. Indeed,
preclinical studies that used mice to investigate A? clearance
showed that efflux across blood-brain barrier (BBB) and brain
degradation mediate efficient A? clearance. However, the
contribution of each process to A? clearance remains unclear.
Moreover, it is still uncertain how species differences between
mouse and human could affect A? clearance. Here, a modified
form of the brain efflux index method was used to estimate the
contribution of BBB and brain degradation to A? clearance from
the brain of wild type mice. We estimated that 62% of
intracerebrally injected (125)I-A?40 is cleared across BBB
while 38% is cleared by brain degradation. Furthermore,
in vitro and in silico studies were performed to compare
A? clearance between mouse and human BBB models. Kinetic
studies for A?40 disposition in bEnd3 and hCMEC/D3 cells,
representative in vitro mouse and human BBB models,
respectively, demonstrated 30-fold higher rate of (125)I-A?40
uptake and 15-fold higher rate of degradation by bEnd3 compared
to hCMEC/D3 cells. Expression studies showed both cells to
express different levels of P-glycoprotein and RAGE, while LRP1
levels were comparable. Finally, we established a mechanistic
model, which could successfully predict cellular levels of
(125)I-A?40 and the rate of each process. Established
mechanistic model suggested significantly higher rates of A?
uptake and degradation in bEnd3 cells as rationale for the
observed differences in (125)I-A?40 disposition between mouse
and human BBB models. In conclusion, current study demonstrates
the important role of BBB in the clearance of A? from the
brain. Moreover, it provides insight into the differences
between mouse and human BBB with regards to A? clearance and
offer, for the first time, a mathematical model that describes
A? clearance across BBB.
This model is hosted on
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MODEL1409240002.
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2015-04-15 | MODEL1409240002 | BioModels
Project description:Alzheimer's disease (AD) lacks effective treatments despite being the most prevalent dementia. This study examines whether rapamycin, an mTOR inhibitor with immunomodulatory properties, alleviates AD pathology by regulating microglia (the brain's resident immune cells).Rapamycin was administered orally to 2-month-old 5×FAD and hAPPNL-G-F mice, two amyloid plaque-dominant AD models. Behavioral and AD-pathological assessments were performed at approximately 5 months of age. Primary microglia exposed to rapamycin and fluorescently labeled amyloid-β (Aβ) oligomers were analyzed for phagocytic and degradative functions. The BV2 microglial cell line received rapamycin, oleic acid, and autophagy inhibitors to investigate mechanisms underlying rapamycin-regulated microglial degradation capacity. Oral rapamycin administration significantly reduced cerebral Aβ plaque burden, diminished dystrophic neurites, suppressed glial hyperactivation, and increased plaque-proximal microglial density in both 5×FAD and hAPPNL-G-F mice, ultimately mitigating memory deficits. Mechanistic investigations revealed rapamycin-activated microglial lysosomal degradation pathways, stimulated lipid droplet clearance in BV2 microglia, and enhanced Aβ phagocytic clearance in primary microglia. Our findings provide compelling evidence that rapamycin enhances Aβ clearance by targeting microglial lysosomal function, thereby establishing a novel glia-directed therapeutic strategy for AD.
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