Asrij/OCIAD1 depletion reduces inflammatory microglial activation and ameliorates Aβ pathology in an Alzheimer's disease mouse model
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ABSTRACT:
PROVIDER: PRJNA1137854 | ENA |
REPOSITORIES: ENA
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Project description:Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by the accumulation of amyloid-beta (Ab) plaques and neurofibrillary tangles, neuroinflammation, and glial activation. Asrij/OCIAD1 (Ovarian Carcinoma Immunoreactive Antigen Domain containing protein 1) is an AD-associated factor. Increased Asrij levels in the brains of AD patients and mouse models are linked to the severity of neurodegeneration. However, the contribution of Asrij to AD progression and whether reducing Asrij levels is sufficient to mitigate Ab pathology in vivo is unclear. To explore the impact of Asrij on AD pathology, we deleted asrij in the APP/PS1 mouse model of AD and analyzed the effects on AD hallmarks. We find that Asrij depletion ameliorates cognitive impairments, Ab deposition, neuronal and synaptic damage, and reactive astrogliosis in the AD mouse. Emerging evidence indicates a critical role of microglia in influencing AD pathology. Notably, Asrij-deficient microglia exhibit reduced plaque-associated proliferation and decreased phagocytic activity. Transcriptomic analyses of AD microglia reveal upregulation of energy metabolism pathways and downregulation of innate immunity and inflammatory pathways upon Asrij depletion. Mechanistically, loss of Asrij increases mitochondrial activity and Akt/mTOR signaling and impedes the pro-inflammatory Disease-Associated Microglia (DAM) state. Reduced levels of pro-inflammatory cytokines and decreased STAT3 and NF-kB activation indicate protective changes in AD microglia. Taken together, our results suggest that increased Asrij levels reported in AD, may suppress microglial metabolic activity and promote inflammatory microglial activation, thereby exacerbating AD pathology. Our study establishes a novel role for Asrij in regulating microglial responses to Ab pathology, and could be a potential target for therapeutic intervention.
2024-07-20 | GSE272625 | GEO
Project description:Aberrant increase of arachidonic acid (ARA) has long been implicated in the pathology of Alzheimer's disease (AD), while the underlying causal mechanism remains unclear. In this study, we revealed a link between ARA mobilization and microglial dysfunction in Aβ pathology. Lipidomic analysis of primary microglia from AppNL-GF mice showed a marked increase in free ARA and lysophospholipids (LPLs) along with a decrease in ARA-containing phospholipids, suggesting increased ARA release from phospholipids (PLs). To manipulate ARA-containing PLs in microglia, we genetically deleted Lysophosphatidylcholine Acyltransferase 3 (Lpcat3), the main enzyme catalyzing the incorporation of ARA into PLs. Loss of microglial Lpcat3 reduced the levels of ARA-containing phospholipids, free ARA and LPLs, leading to a compensatory increase in monounsaturated fatty acid (MUFA)-containing PLs in the AppNL-GF mice. Notably, the reduction of ARA in microglia significantly ameliorated oxidative stress and inflammatory responses while enhancing the phagocytosis of Aβ plaques and promoting the compaction of Aβ deposits. Mechanistically, sc-RNA seq suggested that LPCAT3 deficiency facilitates phagocytosis by facilitating de novo lipid synthesis while protecting microglia from oxidative damage. Collectively, our study reveals a novel mechanistic link between ARA mobilization and microglial dysfunction in AD. Lowering brain ARA levels through pharmacological or dietary interventions may be a potential therapeutic strategy to slow down AD progression.
2024-06-05 | GSE268838 | GEO
Project description:Amyloid-beta (Aβ) is a key factor in the onset and progression of Alzheimer's disease (AD). Selenium (Se) compounds show promise in AD treatment. Here, we reveal that selenoprotein K (SELENOK), a selenoprotein involved in immune regulation and potentially related to AD pathology, plays a critical role in microglial immune response, migration, and phagocytosis. In vivo and in vitro studies corroborate that SELENOK deficiency inhibits microglial Aβ phagocytosis, exacerbating cognitive deficits in 5xFAD mice, which are reversed by SELENOK overexpression. Mechanistically, SELENOK is involved in CD36 palmitoylation through DHHC6, regulating CD36 localization to microglial plasma membranes and thus impacting Aβ phagocytosis. CD36 palmitoylation is reduced in the brains of AD patients and mice. Se supplementation promotes SELENOK expression and CD36 palmitoylation, enhancing microglial Aβ phagocytosis and mitigating AD progression. We have identified the regulatory mechanisms from Se-dependent selenoproteins to Aβ pathology, providing novel insights into potential therapeutic strategies involving Se and selenoproteins.
2024-02-29 | GSE255034 | GEO
Project description:In Alzheimer’s disease (AD), sensome receptor dysfunction impairs microglial danger-associated molecular pattern (DAMP) clearance and exacerbates disease pathology. While extrinsic signals including interleukin-33 (IL-33) can restore microglial DAMP clearance, it remains largely unclear how the sensome receptor(s) is regulated and interacts with DAMP during phagocytic clearance. Here, we show that IL-33 induces VCAM1 in microglia, which promotes microglial chemotaxis toward amyloid-beta (Aβ) plaque-associated ApoE, and leads to Aβ clearance. We show that IL-33 stimulates a chemotactic state in microglia, characterized by Aβ-directed migration. Functional screening identified that VCAM1 directs microglial Aβ chemotaxis by sensing Aβ plaque-associated ApoE. Moreover, we found that disrupting VCAM1–ApoE interaction abolishes microglial Aβ chemotaxis, resulting in decreased microglial clearance of Aβ. In patients with AD, higher cerebrospinal fluid levels of soluble VCAM1 were correlated with impaired microglial Aβ chemotaxis. Together, our findings demonstrate that promoting VCAM1–ApoE-dependent microglial functions ameliorates AD pathology.
2023-07-18 | GSE208006 | GEO
Project description:Arachidonic acid mobilization and peroxidation promote microglial dysfunction in Aβ pathology
| PRJNA1118825 | ENA
Project description:A persistent and non-resolving inflammatory response to accumulating Aβ peptide species is a cardinal feature in the development of Alzheimer's disease (AD). In response to accumulating Aβ peptide species, microglia, the innate immune cells of the brain, generate a toxic inflammatory response that accelerates synaptic and neuronal injury. Many pro-inflammatory signaling pathways are linked to progression of neurodegeneration. However, endogenous anti-inflammatory pathways capable of suppressing Aβ-induced inflammation represent a relatively unexplored area. Here we hypothesized that signaling through the prostaglandin-E2 (PGE2) EP4 receptor potently suppresses microglial inflammatory responses to Aβ42 peptides. In cultured microglial cells, EP4 stimulation attenuated levels of Aβ42-induced inflammatory factors and potentiated phagocytosis of Aβ42. Microarray analysis was performed and demonstrated that EP4 stimulation broadly opposed Aβ42-driven gene expression changes in microglia, with enrichment for targets of IRF1, IRF7, and NF-κB transcription factors.
2014-04-25 | GSE55627 | GEO
Project description:Alzheimer's disease (AD) is associated with the formation of extracellular amyloid-β (Aβ) plaque, perturbing the mechanical properties of brain tissue. Microglia sense and integrate biochemical and mechanical cues in their local microenvironment, intimately linked with AD progress. However, little is known about how microglial mechanosensing pathways are implicated in AD pathogenesis. Gene Ontology (GO) analysis of the significantly down-regulated genes in Piezo1 conditional knockout microglia revealed a significant functional reduction in synapse organization, cell-substrate adhesion, and cytoskeleton system-based events (morphogenesis, migration, and endocytosis) in 5×FAD mice.
2022-03-26 | GSE199217 | GEO
Project description:TREM2 Acts Downstream of CD33 in Modulating Microglial Pathology in Alzheimer's Disease
| PRJNA548198 | ENA
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:INTRODUCTION: Gain-of-function mutations in INPP5D, which encodes for the SH2-domain-containing inositol phosphatase SHIP-1, have recently been linked to an increased risk of developing late-onset Alzheimer’s disease (LOAD). Yet, little is currently known in regards to how SHIP-1 affects neurobiology or neurodegenerative disease pathogenesis. METHODS: To bridge this knowledge gap, we generated 5xFAD Inpp5dfl/flCx3cr1Ert2Cre mice to investigate the function of microglial SHIP-1 signaling in response to amyloid beta (Aβ)-mediated pathology. RESULTS: In our studies, we found that SHIP-1 deletion in microglia leads to substantially enhanced recruitment of microglia to Aβ plaques, altered microglial gene expression, and marked improvements in neuronal health. Further, SHIP-1 loss enhanced microglial plaque containment and Aβ engulfment when compared to microglia from Cre-negative 5xFAD Inpp5dfl/fl littermate controls. DISCUSSION: These results define SHIP-1 as a pivotal regulator of microglial responses during Aβ-driven neurological disease.
2023-04-15 | GSE220279 | GEO