Transcriptomic changes mediated by β-amyloid in human aortic endothelial cells (HAOEC)
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE84620 | GEO | 2018/12/31
REPOSITORIES: GEO
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Project description:Genome-wide association studies (GWAS) have identified genes in lipid metabolism,inflammation and vesicular trafficking pathways as risk factors for late onset Alzheimer disease (LOAD). The mechanism by which they cause AD and their relationship to the amyloid cascade affected by genes causing early onset familial AD is unknown. Unproven hypotheses are that these LOAD genes modulate the amyloid cascade itself or downstream targets affected by this cascade.If so, it is likely that these genes and/or other genes in the same pathways may show alterations in their expression as an early consequence of misprocessing of amyloid precursor protein (APP) and accumulation of amyloid β-peptides (Aβ). We report that in three independent APP transgenic mouse models of AD, multiple genes in lipid and inflammation pathways show very early changes in mRNA and protein expression. Many of these changes are reversed by treatment with LXR agonists, which regulate transcription of genes in lipid/inflammation pathways, and which we have previously shown can reverse the cognitive deficits and neuropathology in Tg2756 mice. These results suggest that changes in lipid and inflammation pathways are likely to be very early consequences of APP misprocessing and Aβ accumulation in AD. Moreover, genetic variants within these pathways might affect risk for AD by modulating this early response. These pathways are likely to contain biomarkers of early disease and targets for therapies. TgCRND8 mice and wild-type littermate controls at ages 70, 80, and 150 days (n = 4 mice per cohort) were used in the study.
2014-08-12 | E-GEOD-31372 | biostudies-arrayexpress
Project description:The amyloid precursor protein (APP) plays a central role in the pathogenesis of Alzheimer’s disease (AD). Processing of APP by β- and γ-secretase activities results in the production of ß-amyloid (Aß), the main constituent of Alzheimer plaques, but also in the generation of the APP intracellular domain (AICD). Recently, it has been demonstrated that AICD has transactivation potential, however, the targets of AICD dependent gene regulation and hence the physiological role of AICD remain largely unknown. In this work we analysed transcriptome changes during AICD dependent gene regulation using a human neural cell culture system inducible for expression of AICD, its co-activator Fe65, or the combination of both. Induction of AICD was associated with increased expression of genes with known function in the organization and dynamics of the actin cytoskeleton as well as genes involved in the regulation of apoptosis. Keywords: (Tet-Off)
2006-05-01 | GSE4097 | GEO
Project description:The β-amyloid precursor protein APP and the related APLPs, undergo complex proteolytic processing giving rise to several fragments. Whereas it is well established that Aβ accumulation is a central trigger for Alzheimer disease (AD), the physiological role of APP family members and their diverse proteolytic products is still largely unknown. The secreted APPsα ectodomain has been shown to be involved in neuroprotection and synaptic plasticity. The γ-secretase generated APP intracellular domain AICD, functions as a transciptional regulator in heterologous reporter assays, although its role for endogenous gene regulation has remained controversial. To gain further insight into the molecular changes associated with knockout phenotypes and to elucidate the physiological functions of APP family members including their proposed role as transcriptional regulators we performed a DNA microarray transcriptome profiling of the frontal cortex of adult wild type, APP-/-, APLP2-/- and APPsα knockin (KI) mice, APPα/α, expressing solely the secreted APPsα ectodomain. Biological pathways affected by the lack of APP family members included regulation of neurogenesis, regulation of transcription and regulation of neuron projection development. Comparative analysis of transcriptome changes and qPCR validation identified co-regulated gene sets. Interestingly, these included heat shock proteins and plasticity related genes that were down-regulated in knock-out cortices. In contrast, we failed to detect significant differences in expression of previously proposed AICD target genes including Bace1, Kai1, Gsk3b, p53, Tip60 and Vglut2. Only Egfr was slightly up-regulated in APLP2-/- mice. Comparison of APP-/- and APPα/α with wild-type mice revealed a high proportion of co-regulated genes indicating an important role of the C-terminus for cellular signaling. Finally, comparison of APLP2-/- on different genetic backgrounds revealed that background related transcriptome changes may dominate over changes due to the knockout of a single gene. Shared transcriptome profiles corroborated closely related physiological functions of APP family members in the adult central nervous system. As expression of proposed AICD target genes was not altered in adult cortex, this may indicate that these genes are not affected by lack of APP under resting conditions or only in a small subset of cells. Prefrontal cortices of adult male mice (24 - 28 weeks) of the following genotypes were analyzed: WT (n=3), APP-/- (n=3), APPα/α (n=3), APLP2-/- (n=3), APLP2(R1)-/- (n=3). WT, APP-/-, APPα/α, APLP2-/- had been backcrossed for six generations to C57BL/6 mice. APLP2(R1)-/- harbors the identical knockout allele as APLP2-/- but was back-crossed only once.
2011-03-18 | E-GEOD-25926 | biostudies-arrayexpress
Project description:Early-onset Alzheimer’s disease-like pathology in Down syndrome (DS, trisomy 21) is commonly attributed to an increased dosage of the amyloid precursor protein (APP) gene. To test this central tenet of the amyloid-cascade hypothesis we deleted the supernumerary copy of the APP gene in trisomic DS iPSC, or upregulated APP expression in euploid human pluripotent stem cell lines with dCas9-VP64, and subjected these lines to prolonged cortical neural differentiation. Our data reveal that increased APP gene dosage and expression is necessary and sufficient for increased beta-amyloid production and pyroglutamate(E3)-containing plaque deposition, but is neither sufficient nor required for tau hyperphosphorylation, neurofibrillary tangle formation, or increased oxidative stress-induced apoptosis in neurons. Transcriptome comparisons of the isogenic neurons demonstrates that the supernumerary APP gene copy has profound temporally-modulated genome-wide effects on gene expression during differentiation and maturation of DS neuronal cultures that link APP function to regulation of genes involved in neuronal synaptic function and outgrowth of neuronal processes. Collectively, our data reveal that APP plays an important role in the amyloidogenic aspects of Alzheimer’s disease, but challenge the hypothesis that increased APP levels are solely responsible for hyperphosphorylation of tau or enhanced oxidative stress-induced neuronal cell death in Down syndrome associated AD-pathogenesis.
2018-06-12 | GSE100680 | GEO
Project description:Aβ peptides derived from the amyloid precursor protein (APP) have been strongly implicated in the pathogenesis of Alzheimer’s disease. However, the normal function of APP and the importance of that role in neurodegenerative disease is less clear. We recovered the Drosophila ortholog of APP, Appl, in an unbiased forward genetic screen for neurodegeneration mutants. We performed comprehensive single cell transcriptional and proteomic studies of Appl mutant flies to investigate Appl function in the aging brain.
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Project description:Lysosomal failure underlies pathogenesis of numerous congenital neurodegenerative disorders and is an early and progressive feature of Alzheimer’s disease (AD) pathogenesis. Here, we report that lysosomal dysfunction in Down Syndrome (Trisomy 21) requires the extra gene copy of amyloid precursor protein (APP) and is mediated by the beta cleaved carboxy terminal fragment of APP (APP-βCTF, C99). In primary fibroblasts from individuals with Down Syndrome (DS), lysosomal degradation of autophagic and endocytic substrates is selectively impaired causing them to accumulate in enlarged autolysosomes/lysosomes. Direct measurements of lysosomal pH uncovered a significant elevation (0.6 units) associated with slowed LC3 turnover and the inactivation of cathepsin D (CTSD) and other lysosomal hydrolases known to be unstable or less active when lysosomal pH is persistently elevated. RNA sequencing analysis excluded a transcriptional contribution to hydrolase declines. Normalizing lysosome pH by delivering acidic nanoparticles to lysosomes ameliorated lysosomal deficits, implicating pH elevation as their primary basis. Cortical neurons cultured from the Ts2 mouse model of DS exhibited lysosomal deficits similar to those in DS cells. Lowering APP expression with siRNA or BACE1 inhibition reversed cathepsin deficits in both fibroblasts and neurons. Deleting one BACE1 allele from adult Ts2 mice had similar rescue effects in vivo. The modest elevation of endogenous APP-βCTF needed to disrupt lysosomal function in DS is relevant to sporadic AD where APP-βCTF, but not APP, is also elevated. Our results extend evidence that impaired lysosomal acidification drives progressive lysosomal failure in multiple forms of AD.
2019-05-30 | GSE127880 | GEO
Project description:We have previously demonstrated that Sirt3 gene deletion, a model for metabolic syndrome, leads to brain mitochondrial dysfunction and neuroinflammation. We also reported that silencing of Sirt3 gene in APP/PS1 mice results in exacerbation of insulin resistance, neuroinflammation and β amyloid plaque deposition. To further understand how metabolic syndrome and amyloid pathology interact, we performed RNA-seq analysis of the brain samples from wild type, Sirt3-/- , APP/PS1 and APP/PS1/Sirt3-/- mice.
2022-10-24 | GSE216081 | GEO
Project description:Genome-wide association studies (GWAS) have identified genes in lipid metabolism,inflammation and vesicular trafficking pathways as risk factors for late onset Alzheimer disease (LOAD). The mechanism by which they cause AD and their relationship to the amyloid cascade affected by genes causing early onset familial AD is unknown. Unproven hypotheses are that these LOAD genes modulate the amyloid cascade itself or downstream targets affected by this cascade.If so, it is likely that these genes and/or other genes in the same pathways may show alterations in their expression as an early consequence of misprocessing of amyloid precursor protein (APP) and accumulation of amyloid β-peptides (Aβ). We report that in three independent APP transgenic mouse models of AD, multiple genes in lipid and inflammation pathways show very early changes in mRNA and protein expression. Many of these changes are reversed by treatment with LXR agonists, which regulate transcription of genes in lipid/inflammation pathways, and which we have previously shown can reverse the cognitive deficits and neuropathology in Tg2756 mice. These results suggest that changes in lipid and inflammation pathways are likely to be very early consequences of APP misprocessing and Aβ accumulation in AD. Moreover, genetic variants within these pathways might affect risk for AD by modulating this early response. These pathways are likely to contain biomarkers of early disease and targets for therapies.
2014-08-12 | GSE31372 | GEO
Project description:The β-amyloid precursor protein APP and the related APLPs, undergo complex proteolytic processing giving rise to several fragments. Whereas it is well established that Aβ accumulation is a central trigger for Alzheimer disease (AD), the physiological role of APP family members and their diverse proteolytic products is still largely unknown. The secreted APPsα ectodomain has been shown to be involved in neuroprotection and synaptic plasticity. The γ-secretase generated APP intracellular domain AICD, functions as a transciptional regulator in heterologous reporter assays, although its role for endogenous gene regulation has remained controversial. To gain further insight into the molecular changes associated with knockout phenotypes and to elucidate the physiological functions of APP family members including their proposed role as transcriptional regulators we performed a DNA microarray transcriptome profiling of the frontal cortex of adult wild type, APP-/-, APLP2-/- and APPsα knockin (KI) mice, APPα/α, expressing solely the secreted APPsα ectodomain. Biological pathways affected by the lack of APP family members included regulation of neurogenesis, regulation of transcription and regulation of neuron projection development. Comparative analysis of transcriptome changes and qPCR validation identified co-regulated gene sets. Interestingly, these included heat shock proteins and plasticity related genes that were down-regulated in knock-out cortices. In contrast, we failed to detect significant differences in expression of previously proposed AICD target genes including Bace1, Kai1, Gsk3b, p53, Tip60 and Vglut2. Only Egfr was slightly up-regulated in APLP2-/- mice. Comparison of APP-/- and APPα/α with wild-type mice revealed a high proportion of co-regulated genes indicating an important role of the C-terminus for cellular signaling. Finally, comparison of APLP2-/- on different genetic backgrounds revealed that background related transcriptome changes may dominate over changes due to the knockout of a single gene. Shared transcriptome profiles corroborated closely related physiological functions of APP family members in the adult central nervous system. As expression of proposed AICD target genes was not altered in adult cortex, this may indicate that these genes are not affected by lack of APP under resting conditions or only in a small subset of cells.
2011-03-18 | GSE25926 | GEO
Project description:Alzheimer’s Disease (AD) is a disorder characterized by cognitive decline, neurodegeneration, and accumulation of amyloid plaques and tau neurofibrillary tangles in the brain. Dysregulation of epigenetic histone modifications may lead to expression of transcriptional programs that play a role either in protecting against disease genesis or in worsening of disease pathology. One such histone modification, acetylation of histone H3 lysine residue 27 (H3K27ac), is primarily localized to genomic enhancer regions and promotes active gene transcription. We previously discovered H3K27ac to be more abundant in AD patient brain tissue compared to the brains of age-matched non-demented controls. In this study, we use iPSC-neurons derived from familial AD patients with an amyloid precursor protein (APP) duplication (APPDup neurons) as a model to study the functional effect of lowering CBP/P300 enzymes that catalyze H3K27ac. We found that homeostatic amyloid-reducing genes were upregulated in the APPDup neurons compared to non-demented controls. We lowered CBP/P300 to reduce H3K27ac, which led to decreased expression of numerous of these homeostatic amyloid-reducing genes, along with increased extracellular secretion of a toxic amyloid-β species, Aβ(1-42). Our findings suggest that epigenomic histone acetylation, including H3K27ac, drives expression of compensatory genetic programs in response to AD-associated insults, specifically those resulting from APP duplication, and thus may play a role in mitigating AD pathology in neurons.
2023-12-22 | GSE250567 | GEO