Reduced binding of apoE4 to complement factor H promotes amyloid-β oligomerization and neuroinflammation
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE193513 | GEO | 2023/05/03
REPOSITORIES: GEO
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Project description:The apolipoprotein E4 (APOE4) gene is the strongest genetic risk factor for late-onset Alzheimer’s disease (AD). ApoE is a lipid carrier abundantly expressed in both brain and periphery. As peripheral apoE is separated from brain apoE by the blood-brain barrier, it remains unclear whether peripheral apoE impacts brain functions and AD pathogenesis. To investigate this, we developed novel mouse models that conditionally express human APOE3 or APOE4 only in the liver with no detectable apoE in the brain. We found that liver-expressed apoE4 compromised synaptic plasticity and cognitive behaviors likely by impairing cerebrovascular functions. Remarkably, liver-expressed apoE4 exacerbated brain amyloid pathology, whereas apoE3 reduced it. Our findings demonstrate a pathogenic effect of peripheral apoE4, providing strong rationale for targeting peripheral apoE to treat AD.
2022-06-15 | GSE125501 | GEO
Project description:Apolipoprotein E4 (APOE4) is the strongest genetic risk factor for late-onset Alzheimer’s disease (LOAD), leading to earlier age of clinical onset and exacerbating pathologies. There is a critical need to identify protective targets. Recently, a rare APOE variant, APOE3-R136S (Christchurch), was found to protect against early-onset AD in a PSEN1-E280A carrier. We sought to determine if the R136S mutation also protects against APOE4-driven effects in LOAD. We generated tauopathy mouse and human iPSC-derived neuron models carrying human APOE4 with the homozygous or heterozygous R136S mutation. We found that the homozygous R136S mutation rescued APOE4-driven Tau pathology, neurodegeneration, and neuroinflammation. The heterozygous R136S mutation partially protected against APOE4-driven neurodegeneration and neuroinflammation, but not Tau pathology. Single-nucleus RNA-sequencing revealed that the APOE4-R136S mutation increased disease-protective and diminished disease-associated cell populations in a gene dose-dependent manner. Thus, the APOE-R136S mutation protects against APOE4-driven AD pathologies, providing a target for therapeutic development against AD.
2023-09-21 | GSE217854 | GEO
Project description:In addition to tau and Aβ pathologies, inflammation plays an important role in Alzheimer's disease (AD). Variants in APOE and TREM2 increase AD risk. ApoE4 exacerbates tau-linked neurodegeneration and inflammation in P301S tau mice and removal of microglia blocks tau-dependent neurodegeneration. Microglia adopt a heterogeneous population of transcriptomic states in response to pathology, at least some of which are dependent on TREM2. Previously, we reported that knockout (KO) of TREM2 attenuated neurodegeneration in P301S mice that express mouse Apoe. Because of the possible common pathway of ApoE and TREM2 in AD, we tested whether TREM2 KO (T2KO) would block neurodegeneration in P301S Tau mice expressing ApoE4 (TE4), similar to that observed with microglial depletion. Surprisingly, we observed exacerbated neurodegeneration and tau pathology in TE4-T2KO versus TE4 mice, despite decreased TREM2-dependent microgliosis. Our results suggest that tau pathology-dependent microgliosis, that is, TREM2-independent microgliosis, facilitates tau-mediated neurodegeneration in the presence of ApoE4.
2022-11-30 | GSE206368 | GEO
Project description:Several genetic risk factors for Alzheimer’s Disease (AD) implicate genes involved in lipid metabolism and many of these lipid genes are highly expressed in glial cells. However, the relationship between lipid metabolism in glia and AD pathology remains poorly understood. Through single-nucleus RNA-sequencing of AD brain tissue, we have identified a microglial state defined by the expression of the lipid droplet (LD) associated enzyme ACSL1 with ACSL1-positive microglia most abundant in AD patients with the APOE4/4 genotype. In human iPSC-derived microglia (iMG) fibrillar Aβ (fAβ) induces ACSL1 expression, triglyceride synthesis, and LD accumulation in an APOE-dependent manner. Additionally, conditioned media from LD-containing microglia leads to Tau phosphorylation and neurotoxicity in an APOE-dependent manner. Our findings suggest a link between genetic risk factors for AD with microglial LD accumulation and neurotoxic microglial-derived factors, potentially providing novel therapeutic strategies for AD.
2024-02-01 | GSE254205 | GEO
Project description:The aim of the study was to investigate hepatic gene expression profiles differentially regulated by the APOE genotype in gene targeted replacement mice. The APOE4 genotype is associated with increased mortality in the elderly and is an independent risk factor for age-dependent chronic diseases. However, little is known about the underlying mechanisms and molecular targets involved in the APOE4-risk association. As APOE is centrally involved in lipid and cholesterol metabolism and in large part is produced in the liver, we analyzed hepatic RNA profiles of APOE4- and APOE3-expressing mice. 2 groups of 5 animals with 1 liver extract per animal. Mice were homozygous for a human APOE3 or APOE4 gene targeted replacement of the endogenous mouse Apoe gene (B6.129P2-Apoetm2(APOE*3)Mae N8 or B6.129P2-Apoetm3(APOE*4)Mae N8, Taconic Transgenic ModelsM-bM-^DM-", http://www.taconic.com/wmspage.cfm?parm1=2542), purchased at the age of 6-8 weeks, strain C57BL/6, 3 months old at the performance of the microarray, 6 weeks on a high-fat diet containing 41% energy from milk fat and 2 g/kg cholesterol.
2012-12-15 | E-GEOD-42930 | biostudies-arrayexpress
Project description:Apolipoprotein E4 (APOE4) is the strongest known genetic risk factor for late-onset Alzheimer’s disease (AD). Conditions of stress or injury induce APOE expression within neurons, but the exact roles of neuronal APOE4 in AD pathogenesis are still unclear. Here we report a rigorous characterization of neuronal APOE4 effects on prominent AD-related pathologies by selectively removing APOE4 from neurons in an APOE4-expressing tauopathy mouse model. We found that the removal of neuronal APOE4 led to a drastic reduction in Tau pathology accumulation and spread, gliosis, neurodegeneration, neurodysfunction, and myelin deficits in this tauopathy mouse model. Single-nucleus RNA-sequencing revealed that the removal of neuronal APOE4 greatly diminished neurodegenerative disease-associated subpopulations of neurons, oligodendrocytes, astrocytes, and microglia that were enriched in APOE4-expressing tauopathy mice and whose accumulation correlated to the severity of Tau pathology, neurodegeneration, and myelin deficits. Thus, neuronal APOE4 plays a central role in promoting the development of major AD pathologies and its removal can effectively combat APOE4-driven effects in AD and other tauopathies.
2023-01-06 | GSE221215 | GEO
Project description:The development of treatment for Alzheimer’s Disease (AD) is hindered by a limited understanding of its structural basis. Apolipoprotein E (APOE) ε4 genotype is the most important risk factor for late-onset AD. APOE4 differs from the APOE3 isoform by a single mutation, C112R. Here, we employ crystallography, biophysical methods and computer simulations to dissect the “domino-like” effect of C112R substitution on APOE4 behaviour. We found that the mutation induces long-distance (>15 Å) conformational changes leading to geometrically distinct T-shaped dimeric unit of APOE4 compared to APOE3. By mutagenesis, we demonstrate that the APOE4 unit is more prone to aggregation than that of the APOE3. AD drug candidate tramiprosate and metabolite 3-sulfopropanoic acid induce APOE3-like conformational behaviour in APOE4 and suppress its aggregation propensity. Omics analysis of APOE ε4/ε4 cerebral organoids treated with tramiprosate revealed its effect on cholesteryl esters, the storage product of excess cholesterol. Our results connect the APOE4 structure with its aggregation propensity, which can be further exploited in drug development for neurodegeneration and ageing.
2023-07-20 | PXD036416 | Pride
Project description:We aim to investigate the interaction between two of the major genetic risk factors for AD: inheritance of APOEε4 and deficiency of Triggering Receptor Expressed on Myeloid cells 2 (TREM2). Trem2 deletion worsened memory in AD model mice but not in their WT littermates. Interestingly, the lack Trem2 resulted in a significantly less microglia around amyloid plaques in APP mice expressing both APOE isoforms but had no impact on amyloid load. Gene expression analysis identified as Trem2 signature a cluster of highly connected immune response genes, commonly downregulated as a result of Trem2 deletion in all experimental groups, such as Clec7a, Itgax, Cts7, Mpeg1, Csf1r, Cx3cr1, Pik3cg and Spi1/PU.1. In vitro experiments with primary microglia demonstrated a decrease of Aβ phagocytosis in APOE4 versus APOE3 microglia a difference that was augmented by the absence of Trem2. Our data demonstrate that the lack of Trem2 differentially impact the phenotype and brain transcriptome of APP mice expressing human APOE isoforms probably reflecting the difference between APOE isoforms to transport lipids that can affect APOE receptor-binding properties.
2020-07-09 | GSE144125 | GEO
Project description:Using a transgenic mouse model of AD that expresses human APOE, we identify a unique transcriptional profile associated with APOE4 expression. We also show a sex and APOE interaction, such that both female sex and APOE4 drive expression of this gene profile. We then confirm these findings in human cells, using microglia derived from induced pluripotent stem cells.
2021-09-21 | GSE163857 | GEO
Project description:Recent developments in genome sequencing have expanded the knowledge of genetic factors associated with late-onset Alzheimer’s disease (AD). Among them, genetic variant e4 of the APOE gene (ApoE4) confers the greatest disease risk. Dysregulated glucose metabolism is an early pathological feature of AD. Using isogenic ApoE3 and ApoE4 astrocytes derived from human-induced pluripotent stem cells, we find that ApoE4 increases glycolytic activity but impairs mitochondrial respiration in astrocytes. Ultrastructural and autophagic flux analyses show that ApoE4-induced cholesterol accumulation impairs lysosome-dependent removal of damaged mitochondria. Acute treatment with cholesterol-depleting agents restores autophagic activity, mitochondrial dynamics, and associated proteomes, and extended treatment rescues mitochondrial respiration in ApoE4 astrocytes. Taken together, our study provides a direct link between ApoE4-induced lysosomal cholesterol accumulation and abnormal oxidative phosphorylation.
2023-09-12 | PXD045298 | Pride