Modeling late-onset Alzheimer's disease neuropathology via direct neuronal reprogramming II
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE253174 | GEO | 2024/08/05
REPOSITORIES: GEO
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Project description:Late-onset Alzheimer’s disease (LOAD) is the most common form of AD. However, modeling sporadic LOAD, without clear genetic predispositions, to capture hallmark neuronal pathologies such as extracellular amyloid-β (Aβ) plaque deposition, intracellular tau tangles, and neuronal loss, remains an unmet need. Here, we demonstrate that neurons generated by microRNA-based direct reprogramming of fibroblasts from patients affected by autosomal dominant AD (ADAD) and LOAD in a three-dimensional (3D) environment, effectively recapitulate key neuropathological features of AD without additional cellular or genetic insults. These LOAD neurons exhibit Aβ-dependent neurodegeneration, as treatment with β- or γ-secretase inhibitors before (but not subsequent to) Aβ deposit formation mitigated neuronal death. Moreover, inhibiting age-associated retrotransposable elements (RTEs) in LOAD neurons reduced both Ab deposition and neurodegeneration. Our study underscores the efficacy of modeling late-onset neuropathology of LOAD through high-efficiency microRNA-based neuronal reprogramming.
2024-08-05 | GSE252932 | GEO
Project description:Late-onset Alzheimer’s disease (LOAD) is the most common form of AD. However, modeling sporadic LOAD, without clear genetic predispositions, to capture hallmark neuronal pathologies such as extracellular amyloid-β (Aβ) plaque deposition, intracellular tau tangles, and neuronal loss, remains an unmet need. Here, we demonstrate that neurons generated by microRNA-based direct reprogramming of fibroblasts from patients affected by autosomal dominant AD (ADAD) and LOAD in a three-dimensional (3D) environment, effectively recapitulate key neuropathological features of AD without additional cellular or genetic insults. These LOAD neurons exhibit Aβ-dependent neurodegeneration, as treatment with β- or γ-secretase inhibitors before (but not subsequent to) Aβ deposit formation mitigated neuronal death. Moreover, inhibiting age-associated retrotransposable elements (RTEs) in LOAD neurons reduced both Ab deposition and neurodegeneration. Our study underscores the efficacy of modeling late-onset neuropathology of LOAD through high-efficiency microRNA-based neuronal reprogramming.
2024-08-05 | GSE267613 | GEO
Project description:Extracellular amyloid-β (Aβ) deposition as neuritic plaques and intracellular accumulation of hyperphosphorylated, aggregated tau as neurofibrillary tangles (NFT) are two of the characteristic hallmarks in Alzheimer’s disease (AD). The regional progression of brain atrophy in AD highly correlates with tau accumulation but not amyloid deposition and the mechanisms of tau-mediated neurodegeneration remain elusive. Innate immune responses represent a common pathway for the initiation and progression of some neurodegenerative diseases. To date, little is known about the extent or role of the adaptive immune response in the presence of Aβ or tau pathology. We systematically compared the immunological milieus in the brain of mice with amyloid deposition or tau aggregation and neurodegeneration. We found that mice with tauopathy but not amyloid, developed a unique innate and adaptive immune response and that depletion of microglia or T-cells blocked tau-mediated neurodegeneration. T cells, especially cytotoxic T cells, were markedly increased in areas with tau pathology in mice with tauopathy and in the AD brain. T cell numbers correlated with the extent of neuronal loss, and dynamically transformed their cellular characteristics from activated to exhausted states along with unique TCR clonal expansion. Inhibition of IFN-γ and PD-1signaling both significantly ameliorated brain atrophy. Our results thus reveal a tauopathy and neurodegeneration-related immune hub involving activated microglia and T cell responses, which could serve as therapeutic targets for preventing neurodegeneration in AD and primary tauopathies.
2023-03-01 | GSE221856 | GEO
Project description:Recently, genes associated with immune response and inflammation have been identified as genetic risk factors for late-onset Alzheimer's disease (LOAD). One of them is the rare p.Arg47His (R47H) variant within triggering receptor expressed on myeloid cells 2 (TREM2), which has been shown to increase the risk for developing AD 2-3-fold. Here, we report the generation and characterization of a model of LOAD using lymphoblast-derived iPSCs from patients harbouring the R47H mutation in TREM2 (AD TREM2 iPSCs), as well as from control individuals without dementia (CON iPSCs). iPSCs efficiently differentiate into mature neuronal cultures and comparative global transcriptome analysis identified a distinct gene expression profile in AD TREM2 neuronal cultures. Furthermore, manipulation of the iPSCderived functional neuronal cultures with an Aβ-S8C dimer highlighted metabolic pathways, phagosome and immune response as the most perturbed pathways in AD TREM2 neuronal cultures. Through the construction of an Aβ-induced gene regulatory network, we were able to identify an Aβ signature linked to protein processing in the endoplasmic reticulum (ER) which emphasised ER-stress, as a potential causal role in LOAD. Overall, this study has shown that our AD-iPSC based model can be used for in-depth studies to better understand the molecular mechanisms underlying the etiology of LOAD and provides new opportunities for screening of potential therapeutic targets.
2020-07-15 | GSE143951 | GEO
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:An emerging link between circadian clock function and neurodegeneration has indicated a critical role for the molecular clock in brain health. We previously reported that deletion of the core circadian clock gene Bmal1 abrogates clock function and induces cell-autonomous astrocyte activation. Regulation of astrocyte activation has important implications for protein aggregation, inflammation, and neuronal survival in neurodegenerative conditions such as Alzheimer's disease (AD). Here, we investigated how astrocyte activation induced by Bmal1 deletion regulates astrocyte gene expression, amyloid-beta (Aβ) plaque-associated activation, and plaque deposition. To address these questions, we crossed astrocyte-specific Bmal1 knockout mice (Aldh1l1-CreERT2;Bmal1(fl/fl), termed BMAL1 aKO), to the APP/PS1-21 and the APP(NL-G-F) models of Aβ accumulation. Transcriptomic profiling showed that BMAL1 aKO induced a unique transcriptional profile affecting genes involved in both the generation and elimination of Aβ. BMAL1 aKO mice showed exacerbated astrocyte activation around Aβ plaques and altered gene expression. However, this astrogliosis did not affect plaque accumulation or neuronal dystrophy in either model. Our results demonstrate that the striking astrocyte activation induced by Bmal1 knockout does not influence Aβ deposition, which indicates that the effect of astrocyte activation on plaque pathology in general is highly dependent on the molecular mechanism of activation.
2023-03-14 | GSE227063 | GEO
Project description:Alzheimer’s disease (AD) is a severe1 age-related neurodegenerative disorder characterized by accumulation of beta-amyloid (Aβ) plaques and neurofibrillary tangles, synaptic and neuronal loss, and cognitive decline. Several genes have been implicated in AD, but chromatin state alterations during neurodegeneration remain uncharacterized. Here, we profile transcriptional and chromatin state dynamics across early and late pathology in the hippocampus of an inducible mouse model of AD-like neurodegeneration. We find a coordinated downregulation of synaptic plasticity genes and regulatory regions, and upregulation of immune response genes and regulatory regions, which are targeted by factors that belong to the ETS family of transcriptional regulators, including PU.1. Human regions orthologous to increasing-level enhancers show immune cell-specific enhancer signatures as well as immune cell expression quantitative trait loci (eQTL), while decreasing-level enhancer orthologs show fetal brain specific enhancer activity. Surprisingly, AD-associated genetic variants are specifically enriched in increasing-level enhancer orthologs implicating immune processes in AD predisposition. Indeed, increasing enhancers overlap known AD loci lacking protein-altering variants and implicate additional loci that do not reach genome-wide significance. Our results reveal new insights into the mechanisms of neurodegeneration and establish the mouse as a useful model for functional studies of AD regulatory regions. We profiled gene expression levels through RNA-Seq and histone mark levels through ChIP-Seq to compare control mice to the CK-p25 Alzheimer's disease model at 2 weeks and 6 weeks after induction of neurodegeneration.
2015-02-18 | E-GEOD-65159 | biostudies-arrayexpress
Project description:Alzheimer’s disease (AD) is the most common cause of late-life dementia characterized by progressive neurodegeneration and brain deposition of amyloid-β (Aβ) and phosphorylated tau. The APOE ε2 encoding apolipoprotein E (APOE2) is a protective allele against AD among the three genotypes (APOE ε2, ε3, ε4), while APOE4 is the strongest genetic factor substantially increasing AD risk. APOE regulates brain lipid homeostasis and maintaining synaptic plasticity and neuronal function, where APOE2 has a superior function compared to APOE3 and APOE4. Gene therapy that increases APOE2 levels in the brain is, therefore, a promising therapeutic strategy for AD treatment. We previously reported that PEGylated liposomes conjugated with transferrin and a cell-penetrating peptide Penetratin sufficiently deliver chitosan-APOE2 cDNA plasmid complex into the brain of wild-type mice. Here, we investigated how brain-targeting liposome-based APOE2 gene delivery influences Aβ)-related pathologies in amyloid model AppNL-G-F knockin mice at 12-month-old. We found a trend of reductions of insoluble Aβ levels in the mouse cortices 1 month after APOE2 gene therapy. Furthermore, in the AppNL-G-F knockin mice that received the APOE2 gene therapy, brain transcriptome analysis through RNA-sequencing identified the upregulation of genes/pathways related to neuronal development. This was supported by increases of Dlg4 and Syp mRNAs coding synaptic proteins in the experimental group. On the other hand, we found that APOE2 gene delivery increased soluble Aβ levels, including oligomers, as well as exacerbated neurite dystrophy and decreased synaptophysin. Together, our results suggest that brain-targeting liposome-based APOE2 gene therapy is potentially beneficial for synaptic formation at the transcriptional level. Forced APOE2 expressions, however, may exacerbate Aβ toxicity by increasing the dissociation of Aβ oligomers from aggregates in the presence of considerable amyloid burden.
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2010-05-30 | GSE20447 | GEO
Project description:Selective neurodegeneration is a critical causal factor in Alzheimer’s disease (AD); however, the mechanisms that lead some neurons to perish while others remain resilient are unknown. We sought potential drivers of this selective vulnerability using single-nucleus RNA sequencing and discovered that apoE expression level is a substantial driver of neuronal variability. Strikingly, neuronal expression of apoE—which has a robust genetic linkage to AD—correlated strongly, on a cell-by-cell basis, with immune response pathways in neurons in the brains of wildtype mice, human apoE knock-in mice, and humans with or without AD. Elimination or over-expression of neuronal apoE revealed a causal relationship between apoE expression, neuronal MHC-I expression, Tau pathology, and neurodegeneration. Functional reduction of MHC-I ameliorated Tau pathology in apoE4-expressing primary neurons and in mouse hippocampi expressing pathological Tau. These findings suggest a mechanism linking neuronal apoE expression to MHC-I expression and, subsequently, to Tau pathology and selective neurodegeneration.
2021-04-19 | GSE167497 | GEO