Global knock out of Sirt3 gene in Alzheimer’s transgenic mice with amyloid pathology
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE216081 | GEO | 2022/10/24
REPOSITORIES: GEO
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Project description:Alzheimer's disease (AD) is the most common neurodegenerative disorder affecting memory and cognition. The disease is accompanied by an abnormal deposition of ß-amyloid plaques in the brain that contributes to neurodegeneration and is known to induce glial inflammation. Studies in the APP/PS1 mouse model of ß-amyloid-induced neuropathology have suggested a role for inflammasome activation in ß-amyloid-induced neuroinflammation and neuropathology. Here, we evaluated the in vivo role of microglia-selective and full body inflammasome signalling in several mouse models of ß-amyloid-induced AD neuropathology. Unexpectedly, microglia-specific deletion of the inflammasome regulator A20 and inflammasome effector protease caspase-1 in the AppNL-G-F and APP/PS1 models failed to identify a prominent role for microglial inflammasome signalling in ß-amyloid-induced neuropathology. Moreover, global inflammasome inactivation through respectively full body deletion of caspases 1 and 11 in AppNL-G-F mice and Nlrp3 deletion in APP/PS1 mice, also failed to modulate amyloid pathology and disease progression. In agreement, single-cell RNA sequencing did not reveal an important role for Nlrp3 signalling in driving microglial activation and the transition into disease-associated states, both during homeostasis and upon amyloid pathology. Collectively, these results question a generalizable role for inflammasome activation in pre-clinical amyloid-only models of neuroinflammation.
2024-01-17 | GSE249611 | GEO
Project description:Alzheimer’s disease (AD) is a common form of dementia characterized by amyloid plaque deposition, TAU pathology, neuroinflammation and neurodegeneration. Mouse models recapitulate some key features of AD. For instance, the B6.APP/PS1 model (carrying human transgenes for mutant forms of APP and PSEN1) shows plaque deposition and associated neuroinflammatory responses involving both astrocytes and microglia beginning around 6 months of age. However, in our colony, TAU pathology, significant neurodegeneration and cognitive decline are not apparent in this model even at older ages. Therefore, this model is ideal for studying neuroinflammatory responses to amyloid deposition. Here, RNA sequencing of brain and retinal tissue, generalized linear modeling (GLM), functional annotation followed by validation by immunofluorescence (IF) was performed in B6.APP/PS1 mice to determine the earliest molecular changes prior to and around the onset of plaque deposition (2-6 months of age).
2019-11-25 | GSE136861 | GEO
Project description:Blood-brain barrier (BBB) dysfunction is emerging as a key pathogenic factor in the progression of Alzheimer’s disease (AD), where increased microvascular endothelial permeability has been proposed to play an important role. However, the molecular mechanisms leading to increased brain microvascular permeability in AD are not fully understood. We observed that brain endothelial permeability in the APPswe/PS1DE9 (APP/PS1) transgenic mouse model of amyloid-beta (Ab) amyloidosis increases with aging in the areas with the greatest amyloid plaque deposition. We performed an unbiased bulk RNA-sequencing analysis of brain endothelial cells (BECs) in APP/PS1 transgenic mice. We observed that upregulation of interferon signaling gene expression pathways in BECs were among the most prominent transcriptomic signatures in the brain endothelium of APP/PS1 mice. Immunofluorescence analysis of isolated BECs from APP/PS1 mice demonstrated higher levels of the Type I interferon-stimulated gene IFIT2. Immunoblotting of APP/PS1 BECs showed downregulation of the adherens junction protein VE-cadherin. Stimulation of human brain endothelial cells with interferon-β decreased the levels of the adherens junction protein VE-cadherin as well as tight junction proteins Occludin and Claudin-5 and increased barrier leakiness. Depletion of the Type I interferon receptor in human brain endothelial cells prevented interferon-β-induced VE- cadherin downregulation and restored endothelial barrier integrity. Our study suggests that Type I interferon signaling contributes to brain endothelial dysfunction in AD.
2022-06-25 | GSE206629 | GEO
Project description:RNA samples from the cerebral cortex of APP/PS1 and WT mouse littermates aged 3, 6 and 12 months were analyzed using the Affymetrix Genechip Mouse Gene 1.1 ST Array. The APP-PS1 transgenic mouse express the human mutated forms APPswe and PS1dE9. This is a good model of familial Alzheimer Disease because it reproduces several features of the disease as β-amyloid deposits throughout the brain and exhibit memory impairment by the end of the sixth month and is a simple model to study the molecular pathways. The aim of this study is to identify dysregulation of inflammation pathways in order to understand shifts of inflammation responses with disease progression.
2014-04-30 | E-MTAB-2121 | biostudies-arrayexpress
Project description:Aβ is a peptide of 39-42 amino acid residues that derived from putative intramembranous processing of amyloid precursor protein (APP) at the proposed active site of the γ-secretase/PS1 aspartyl. Aβ has been shown to aggregate and accumulate abnormally in the brain of AD (Alzheimer's disease), and extracellular amyloid plaques of Aβ peptides aggregation can trigger a cascade of pathologic events leading to nerve fiber entanglement and neuronal apoptosis protease. We used microarrays to investigate the effects of HPYD on the gene expression of APP/PS1 transgenic mice, the brain tissues of control group, model group and HPYD group mice.
2018-02-23 | GSE104249 | GEO
Project description:Tumor cells exhibit aberrant metabolism characterized by high glycolysis even in the presence of oxygen. This metabolic reprogramming, known as the Warburg effect, provides tumor cells with the substrates and redox potential required for the generation of biomass. Here, we show that the mitochondrial NAD-dependent deacetylase SIRT3 is a crucial regulator of the Warburg effect. SIRT3 loss promotes a metabolic profile consistent with high glycolysis required for anabolic processes in vivo and in vitro. Mechanistically, SIRT3 mediates metabolic reprogramming independently of mitochondrial oxidative metabolism and through HIF1a, a transcription factor that controls expression of key glycolytic enzymes. SIRT3 loss increases reactive oxygen species production, resulting in enhanced HIF1a stabilization. Strikingly, SIRT3 is deleted in 40% of human breast cancers, and its loss correlates with the upregulation of HIF1a target genes. Finally, we find that SIRT3 overexpression directly represses the Warburg effect in breast cancer cells. In sum, we identify SIRT3 as a regulator of HIF1a and a suppressor of the Warburg effect. RNA isolated from brown adipose tissue of SIRT3 WT and KO mice. 5 wild-type samples and 5 SIRT3 KO samples
2011-03-15 | E-GEOD-27309 | biostudies-arrayexpress
Project description:To identify the differentially expressed genes in the brain of WT mice in comparison with 9-month-old APP/PS1 mice, we examined the microarray gene expression profile of the groups above. Neuroinflammation is well implicated in the progression of Alzheimer’s Disease (AD) now. What’ more, neuroinflammation is supposed to be one of the essential trigger to induce neurodegeneration. In this study, we examined the differentially expressed genes (including coding transcripts and lncRNA) between the wild type (WT) mouse and a AD model, the APP/PS1 mouse. We found that, among all these P2XR family genes, P2X7R is not only the most abundant expressed, but also identified as the highest upregulated gene. The elevated P2X7R expression promotes neuroinflammation through activation of NLRP3 inflammsome, and further mediate one kind of inflammatory cell death, pyroptosis. Blockade of P2X7R could not only inhibit pyroptosis, but also could mildly alleviate cognitive deficits in APP/PS1 mice. Our study provides new insight into an alternative strategy for the development of AD therapy.
2021-01-01 | GSE109479 | GEO
Project description:Background: ABCA1 has recently been identified as a novel genetic risk factor for Alzheimer’s disease. The major known role of ABCA1 in the brain is to transfer lipids onto lipid poor APOE. Given that APOEε4 is the strongest genetic risk factor for developing late onset Alzheimer’s disease, this recent finding implicates the cholesterol homeostatic pathway in the onset/progression of Alzheimer’s disease. microRNAs (miRs) are small RNA species that negatively regulate expression of their target genes. ABCA1 is regulated by miR-33, and loss of this miR significantly increases protein levels of ABCA1 and increases the lipidation of APOE. However, it is unknown if loss of miR-33 and subsequent increase in ABCA1 protein levels ameliorates amyloid pathology. Methods: We generated miR-33+/+;APP/PS1 and miR-33-/-;APP/PS1 mice to determine changes in amyloid-beta (Aβ) peptides and amyloid plaque formation utilizing biochemical and histological analyses. In addition to amyloid pathology, we assessed if deletion of miR-33 altered the activation of glial cells in the brains of these mice. We utilized in vitro methods to determine if miR-33 alters the phagocytosis of Aβ aggregates. We utilized RNA-sequencing and mass spectrometry to identify the transcriptome and proteome regulation by miR-33 in the context of amyloid pathology. Results: Deletion of miR-33 dramatically reduces insoluble Aβ peptide levels and the deposition of amyloid plaques in APP/PS1 mice. In addition, we identified that astrocyte and microglial activation is markedly decreased in miR-33-/-;APP/PS1 mice through histological analyses. Intriguingly, we show that loss of miR-33 results in amyloid plaques that are more compact, potentially implicating enhanced microglial phagocytosis. We confirm in vitro that loss of miR-33 significantly increases microglial phagocytosis of Aβ aggregates. Our multi-omics analyses reveal that deletion of miR-33 regulates immune response in the context of amyloid pathology. Interestingly, we identified that WNT/Beta-catenin signaling is significantly upregulated in miR-33-/-;APP/PS1 mice. Conclusion: We confirm that the deletion of miR-33 increases APOE lipidation and significantly reduces amyloid pathology as well as glial activation in APP/PS1 mice. Our results agree with previous work identifying APOE lipidation as an important modulator of amyloid pathology. We show, for the first time, that loss of miR-33 increases the phagocytosis of Aβ by microglia. In total, we identify miR-33 as a promising target for the amelioration of amyloid pathology.
2024-09-30 | GSE235179 | GEO
Project description:Immune cell infiltration to the brain is a prominent feature in aging and in various neurodegenerative diseases such as Alzheimer´s disease (AD). For example, a specific subpopulation of CD8+ T-cells clonally expands in the CSF of AD patients. Also, with AD progression that typically includes amyloid-beta plaque formation, neuronal damage and microglia-associated neuroinflammation, CD8+ T-cells infiltrate into the AD brain parenchyma and tightly associate with neuronal and microglia structures. The functional properties of CD8+ T-cells in the brain are largely unknown, besides the fact that experimental ablation in a transgenic AD animal model (APP-PS1) leads to changes in the expression of neuronal- and synapse-related genes. To gain further insights into the putative functional role of CD8+ T-cells in the brain, we explored and compared the transcriptomic profile of these cells in blood and brain of aged and transgenic AD mice. Surprisingly, CD8+ T-cells isolated from brains of aged APP-PS1 and WT animals had a similar transcriptomic profile, but they substantially differed from blood circulating CD8+ T-cells. The gene expression signature of brain CD8+ T-cells from APP-PS1 mice identified these cells as tissue-resident memory T-cells (Trm) indicated by specific regulation of genes such as Klf2/3, Ccr7, Sell, and Cxcr6. Immunohistochemical analysis confirmed the Trm identity of CD8+ T-cells at sites of amyloid-plaques. Gene ontology enrichment analysis on the significantly up-regulated genes showed an overrepresentation of biological processes as “response to virus”, “T-cell mediated immunity” and “response to interferon-beta” suggesting similarities to virus-responding T-cells. This is also supported by KEGG analysis, which highlighted upregulation of several pathways for “virus infections”, “cellular senescence” and “antigen processing and presentation”. In addition, the transcriptome of APP-PS1 brain CD8+ T-cells overlapped with gene microarray data of brain Trm CD8+ T-cells derived from an acute virus infection mouse model, suggesting similar functions of CD8+ T-cells in the brain either after viral infections or in AD. In conclusion, our herein presented data give new insights on the transcriptome of brain CD8+ T-cells and demonstrate adaptive immune responses in transgenic AD mice. This might open the door for immunotherapy as potential treatment option for AD.
2022-08-02 | GSE180746 | GEO
Project description:While mitochondrial dysfunction is implicated in metabolic dysfunction associated steatohepatitis (MASH), the precise underlying mechanisms remain obscure. Here, we identify the SIRT3-DsbA-L-TFAM axis as a crucial suppressor for mitochondrial stress-induced cGAS activation in the hepatocytes, thereby alleviating MASH in mice. SIRT3 facilitates the deacetylation of Disulfide-bond-A oxidoreductase-like protein (DsbA-L) at lysine residues (Lys165, Lys167, and Lys177), which promotes the interaction between DsbA-L and mitochondrial transcription factor A (TFAM), essential for the preservation of mitochondrial integrity and function. Hepatocyte-specific knockout of SIRT3 or DsbA-L in male mice promoted mitochondrial DNA release into the cytosol, resulting in activation of the cGAS-STING pathway and exacerbation of MASH characteristics. Conversely, hepatocyte-specific knockout of cGAS or overexpression of DsbA-L mitigated diet- and SIRT3 deficiency-induced MASH progression. Our study underscores the clinical significance of targeting SIRT3 and cGAS as pivotal therapeutic avenues to inhibit the progression of MASH.
2024-11-30 | GSE281667 | GEO