A1-Reactive Astrocytes and a loss of TREM2 are associated to an early state of pathology in a mouse model of Cerebral Amyloid Angiopathy
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE150394 | GEO | 2020/07/22
REPOSITORIES: GEO
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Project description:Cerebral amyloid angiopathy (CAA) is the leading cause of vascular dementia among the elderly. Neuropsychiatric symptoms are commonly manifested in CAA patients but are usually considered as consequences of CAA pathology. Here, we report that chronic stress promotes CAA progression, which enhances deposition of amyloid protein beta (Aβ) in brain blood vessels and exacerbates subsequent brain injury. Mechanistically, neutrophil is implicated in CAA development. Aβ that accumulated in brain vasculature induces neutrophil extracellular traps (NETs) by activating STAT6 signaling, which inhibits neutrophil apoptosis and switches the programmed cell death toward NETosis. During chronic stress, circulatory Norepinephrine (NE) strengthens STAT6 activation in neutrophil and promotes NET formation, thus exacerbates the NET-dependent angiopathy. We demonstrate that inhibiting neutrophil chemotaxis towards brain or suppressing NET formation both ameliorate CAA severity in the context of chronic stress. Therefore, we propose that stress-associated psychological disorders and NETs are promising therapeutic targets in CAA.
2024-12-15 | GSE249924 | GEO
Project description:Cerebral amyloid angiopathy (CAA) is the leading cause of vascular dementia among the elderly. Neuropsychiatric symptoms are commonly manifested in CAA patients but are usually considered as consequences of CAA pathology. Here, we report that chronic stress promotes CAA progression, which enhances deposition of amyloid protein beta (Aβ) in brain blood vessels and exacerbates subsequent brain injury. Mechanistically, neutrophil is implicated in CAA development. Aβ that accumulated in brain vasculature induces neutrophil extracellular traps (NETs) by activating STAT6 signaling, which inhibits neutrophil apoptosis and switches the programmed cell death toward NETosis. During chronic stress, circulatory Norepinephrine (NE) strengthens STAT6 activation in neutrophil and promotes NET formation, thus exacerbates the NET-dependent angiopathy. We demonstrate that inhibiting neutrophil chemotaxis towards brain or suppressing NET formation both ameliorate CAA severity in the context of chronic stress. Therefore, we propose that stress-associated psychological disorders and NETs are promising therapeutic targets in CAA.
2024-12-15 | GSE249922 | GEO
Project description:BackgroundCerebral amyloid angiopathy (CAA) is typified by the cerebrovascular deposition of amyloid. The mechanisms underlying the contribution of CAA to neurodegeneration are not currently understood. Although CAA is highly associated with the accumulation of amyloid beta (Aβ), other amyloids are known to associate with the vasculature. Alzheimer's disease (AD) is characterized by parenchymal Aβ deposition, intracellular accumulation of tau, and significant neuroinflammation. CAA increases with age and is present in 85-95% of individuals with AD. A substantial amount of research has focused on understanding the connection between parenchymal amyloid and glial activation and neuroinflammation, while associations between vascular amyloid pathology and glial reactivity remain understudied.MethodsHere, we dissect the glial and immune responses associated with early-stage CAA with histological, biochemical, and gene expression analyses in a mouse model of familial Danish dementia (FDD), a neurodegenerative disease characterized by the vascular accumulation of Danish amyloid (ADan). Findings observed in this CAA mouse model were complemented with primary culture assays.ResultsWe demonstrate that early-stage CAA is associated with dysregulation in immune response networks and lipid processing, severe astrogliosis with an A1 astrocytic phenotype, and decreased levels of TREM2 with no reactive microgliosis. Our results also indicate how cholesterol accumulation and ApoE are associated with vascular amyloid deposits at the early stages of pathology. We also demonstrate A1 astrocytic mediation of TREM2 and microglia homeostasis.ConclusionThe initial glial response associated with early-stage CAA is characterized by the upregulation of A1 astrocytes without significant microglial reactivity. Gene expression analysis revealed that several AD risk factors involved in immune response and lipid processing may also play a preponderant role in CAA. This study contributes to the increasing evidence that brain cholesterol metabolism, ApoE, and TREM2 signaling are major players in the pathogenesis of AD-related dementias, including CAA. Understanding the basis for possible differential effects of glial response, ApoE, and TREM2 signaling on parenchymal plaques versus vascular amyloid deposits provides important insight for developing future therapeutic interventions.
| S-EPMC7382050 | biostudies-literature
Project description:Alzheimer's disease (AD) and cerebral amyloid angiopathy (CAA) are neurodegenerative disorders characterized by the pathological deposition of amyloid-beta (Aβ) in the brain. Although both conditions share common pathogenic pathways, they exhibit distinct cellular manifestations and disease progression. Our study focused on the differential expression and role of astrocytic colony-stimulating factor 1 (CSF1) in these diseases. Using transcriptomic analysis of 248 brain tissue samples from the hippocampal-entorhinal system of 50 individuals, we identified a significant increase in CSF1 expression in the CA4 subfield of AD patients compared to a marked decrease in CAA. Functional investigations revealed that astrocytes with elevated CSF1 levels displayed neurotoxicity associated with AD-like pathology, whereas reduced CSF1 expression in astrocytes was linked to vascular damage typical of CAA. These findings suggest that CSF1 plays divergent roles in AD and CAA, contributing to their distinct pathological profiles. Our study highlights the potential of targeting astrocytic CSF1 expression as a differential diagnostic marker and therapeutic approach in managing these overlapping yet distinct neurological conditions.
2024-12-15 | GSE278723 | GEO
Project description:There is a growing recognition of cerebrovascular contribution to neurodegenerative diseases. Cerebral amyloid angiopathy (CAA), characterised by amyloid-beta (AM-NM-2) deposits in the walls of intracerebral and leptomeningeal arteries, is evident in a majority of AlzheimerM-bM-^@M-^Ys disease patients and aged people. Here, we leverage on human pluripotent stem cells to generate vascular smooth muscle cells (SMCs) from neural crest progenitors, recapitulating brain vasculature-specific attributes in AM-NM-2 metabolism. We confirm that the lipoprotein receptor, LRP1, functions in our neural crest-derived SMCs to mediate AM-NM-2 uptake and intracellular proteasomal degradation. Hypoxia significantly compromises the ability of SMCs in AM-NM-2 clearance by suppressing LRP1 expression. This enables us to develop an assay of AM-NM-2 uptake using the neural crest-derived SMCs with hypoxia as a stress paradigm. We then tested several vascular protective compounds in a high throughput format, demonstrating the value of stem cell-based phenotypic screening for novel CAA therapeutics and drug repurposing. We adopted our previous SMC differentiation protocol (Cheung et al., 2012) to differentiate this intermediate neural crest population using platelet-derived growth factor BB (PDGF-BB, 10 ng/ml) and transforming growth factor-beta 1 (TGF-M-NM-21, 2ng/ml) for another 12 days. The resultant neural crest-derived SMCs (NCSMC) were then characterised in comparison to neuroectoderm-derived SMCs (NESMC) (Cheung et al., 2012) and positive control, human brain vascular SMCs (BVSMC).
2015-01-21 | E-GEOD-55173 | biostudies-arrayexpress
Project description:There is a growing recognition of cerebrovascular contribution to neurodegenerative diseases. Cerebral amyloid angiopathy (CAA), characterised by amyloid-beta (Aβ) deposits in the walls of intracerebral and leptomeningeal arteries, is evident in a majority of Alzheimer’s disease patients and aged people. Here, we leverage on human pluripotent stem cells to generate vascular smooth muscle cells (SMCs) from neural crest progenitors, recapitulating brain vasculature-specific attributes in Aβ metabolism. We confirm that the lipoprotein receptor, LRP1, functions in our neural crest-derived SMCs to mediate Aβ uptake and intracellular proteasomal degradation. Hypoxia significantly compromises the ability of SMCs in Aβ clearance by suppressing LRP1 expression. This enables us to develop an assay of Aβ uptake using the neural crest-derived SMCs with hypoxia as a stress paradigm. We then tested several vascular protective compounds in a high throughput format, demonstrating the value of stem cell-based phenotypic screening for novel CAA therapeutics and drug repurposing.
2015-01-21 | GSE55173 | GEO
Project description:Different forms of dementia are caused by stop-loss mutations in the ITM2B gene, also known as Bri2, which result in the expression of 34 amino acid long peptides that accumulate as amyloids in human brains. In order to gather mechanistic insights into the formation of amyloids by two of these peptides, ADan and ABri - hallmarks of Danish and British dementia respectively - we employed saturation mutagenesis combined to a massively parallel selection assay that reports on amyloid nucleation. Our results reveal that ADan aggregates into amyloids remarkably faster than both the unextended peptide Bri2 and the extended ABri sequence. The complete mutational landscape of ADan reveals asparagines and charged residues as key players in the nucleation process in addition to aliphatic residues within positions 20-25. What is more, we show that extending Bri2 with just two specific residues is enough to generate a novel amyloid core which we suggest builds the structured core of ADan fibrils. On the other hand, only a handful of mutations can boost the ability of ABri to nucleate amyloids, including a SNV replacing the Bri2 stop codon by a Cys codon. Overall, the remarkably different aggregation profiles and mutational landscapes for the two peptides suggest that different disease mechanisms underlie disease in Danish and British dementia and highlight the importance of accurately measuring the impact of stop extension mutations for these and other sequences across the genome.
2023-10-09 | GSE244612 | GEO
Project description:Loss of TREM2 exacerbates parenchymal amyloid pathology but diminishes CAA in Tg-SwDI mice
| PRJNA1022068 | ENA
Project description:BackgroundCortical superficial siderosis (cSS) has recently emerged as one of the most important predictors of symptomatic intracerebral hemorrhage and is a risk factor for post-stroke dementia in cerebral amyloid angiopathy (CAA). However, it remains unknown whether cSS is just a marker of severe CAA pathology or may itself contribute to intracerebral hemorrhage risk and cognitive decline. cSS is a chronic manifestation of convexal subarachnoid hemorrhage and is neuropathologically characterized by iron deposits in the superficial cortical layers. We hypothesized that these iron deposits lead to local neuroinflammation, a potentially contributory pathway towards secondary tissue injury.MethodsAccordingly, we assessed the distribution of inflammatory markers in relation to cortical iron deposits in post-mortem tissue from CAA cases. Serial sections from the frontal, parietal, temporal, and occipital lobes of nineteen autopsy cases with CAA were stained with Perls' Prussian blue (iron) and underwent immunohistochemistry against glial fibrillary acidic protein (GFAP, reactive astrocytes) and cluster of differentiation 68 (CD68, activated microglia/macrophages). Digitized sections were uploaded to the cloud-based Aiforia® platform, where deep-learning algorithms were utilized to detect tissue, iron deposits, and GFAP-positive and CD68-positive cells.ResultsWe observed a strong local relationship between cortical iron deposits and reactive astrocytes. Like cSS-related iron, reactive astrocytes were mainly found in the most superficial layers of the cortex. Although we observed iron within both astrocytes and activated microglia/macrophages on co-stains, there was no clear local relationship between the density of microglia/macrophages and the density of iron deposits.ConclusionIron deposition resulting from cSS is associated with local reactive astrogliosis.
| S-EPMC10463916 | biostudies-literature
Project description:A1-Reactive Astrocytes and a loss of TREM2 are associated to an early state of pathology in a mouse model of Cerebral Amyloid Angiopathy
| PRJNA631972 | ENA