Type-I Interferon drives T-cell responses to Amyloid-beta in the central nervous system
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE280018 | GEO | 2026/01/01
REPOSITORIES: GEO
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Project description:One of the hallmarks of Alzheimer’s disease is the presence of extracellular diffuse and fibrillar plaques predominantly consisting of the amyloid-β (Aβ) peptide. ApoE influences the deposition of amyloid pathology through affecting the clearance and aggregation of monomeric Aβ in the brain. In addition to influencing Aβ metabolism, increasing evidence suggests that apoE influences microglial function in neurodegenerative diseases. Here, we characterize the impact that apoE has on amyloid pathology and the innate immune response in APPPS1∆E9 and APPPS1-21 transgenic mice. We report that Apoe deficiency reduced fibrillar plaque deposition consistent with previous studies. However, fibrillar plaques in Apoe-deficient mice exhibited a striking reduction in plaque compaction. Hyperspectral fluorescent imaging using luminescent conjugated oligothiophenes identified distinct Aβ morphotypes in Apoe-deficient mice. We also observed a significant reduction in fibrillar plaque-associated microgliosis and activated microglial gene expression in Apoe-deficient mice, along with significant increases in dystrophic neurites around fibrillar plaques. Our results suggest that apoE is critical in stimulating the innate immune response to amyloid pathology.
2018-02-15 | GSE109906 | GEO
Project description:Anti-amyloid β-peptide (Aβ) immune therapy was developed as treatment for Alzheimer’s disease (AD) to reduce and prevent amyloid plaque pathology. This approach has proven successful in phase 3 clinical trials of Aducanumab, Lecanemab and Donanemab. These antibodies induce robust amyloid plaque clearance, slow memory decline, and have beneficial effects on daily living activities. The therapeutic effects correlate with the efficacy of plaque removal. Treatment is associated with adverse side-effects, such as oedema and haemorrhages (ARIA-E and -H), which are potentially linked to the induced immune response. To improve therapeutic safety, it is therefore imperative to understand the effects of anti-Aβ antibody treatment on immune cell function. We investigated the effects of long-term chronic Aducanumab treatment on amyloid plaque pathology and microglial response in the APP-SAA triple knock-in mouse model. Mice were treated weekly with Aducanumab from 4-8 months of age. Long-term treatment with Aducanumab results in a robust and dose-dependent removal of amyloid plaque pathology. Analysis of the CSF proteome indicates a reduction of markers for neurodegeneration including tau and α-synuclein. Consistent with a reduction of glucose uptake, the therapeutic effects were accompanied by reduced microglial activation. RNAseq confirmed a dose-dependent decrease in the disease-associated microglia (DAM) transcriptional signature of microglia, which is supported by a parallel decrease of Trem2 protein. However, genes associated with antigen-presentation were still increased after treatment. IHC confirms that Aducanumab treatment increases microglial clustering, as well as MHC-II expression around plaques and ELISA confirmed increased cytokine levels. These findings demonstrate that long-term chronic Aducanumab-mediated removal of Aβ leads to a dose dependent decrease in microglial activation and neurodegeneration, but induces a unique antibody treatment-related microglial phenotype associated with antigen presentation, which may be related to plaques still present after the 4 months treatment period.
2025-08-20 | GSE288801 | GEO
Project description:The major genetic risk factor for Alzheimer’s disease (AD), APOE4, accelerates beta-amyloid (Aβ) plaque formation, but whether this is caused by APOE expressed in microglia or astrocytes is debated. We express here the human APOE isoforms in astrocytes in an Apoe-deficient AD mouse model. This is not only sufficient to restore the amyloid plaque pathology but also induces the characteristic transcriptional pathological responses in Apoe-deficient microglia surrounding the plaques. We find that both APOE4 and the protective APOE2 from astrocytes increase fibrillar plaque deposition, but differentially affect soluble Aβ aggregates. Microglia and astrocytes show specific alterations in function of APOE genotype expressed in astrocytes. Our experiments indicate a central role of the astrocytes in APOE mediated amyloid plaque pathology and in the induction of associated microglia responses.
2024-10-04 | GSE252454 | GEO
Project description:Anti-amyloid β-peptide (Aβ) immunotherapy was developed as treatment for Alzheimer’s disease to reduce and prevent amyloid plaque pathology and its downstream consequences. Efficient amyloid plaque clearance has been proven in clinical trials with Aducanumab, Lecanemab and Donanemab. At least two of these antibodies slow memory decline to some extent and have beneficial effects on daily living activities. The therapeutic effects correlate with the efficacy of plaque removal. However, treatment is associated with adverse side-effects, such as oedema and haemorrhages, which are potentially linked to the induced immune response. To improve therapeutic safety, it is therefore imperative to understand the consequences of anti-Aβ antibody treatment on immune cell function. Here, we investigated the effects of long-term chronic Aducanumab treatment on amyloid plaque pathology and microglial response in the APP-SAA triple knock-in mouse model. Mice were treated weekly with Aducanumab from 4-8 months of age. Long-term treatment with Aducanumab results in a robust and dose-dependent removal of amyloid plaque pathology, with a higher efficiency for removing diffuse over dense-core plaques. Analysis of the CSF proteome indicates a reduction of markers for neurodegeneration including Tau and α-Synuclein, as well as immune cell related proteins.
2025-08-25 | PXD061932 | Pride
Project description:Proteins associated with amyloid-β (Aβ) pathology are critical biomarkers and potential therapeutic targets for Alzheimer’s disease (AD). Previous studies analyzing Aβ plaque composition relied on micro-dissected plaques from tissue samples. Here, we aimed to study the proteome associated with Aβ40- and Aβ42-plaques to identify protein constituents of Aβ plaques—actual Aβ40- and Aβ42-fibril interactors—, which might drive Aβ plaque development. Biotinylated-Aβ40, or -Aβ42, were incubated to form fibrils, with scrambled peptides used as control, and subjected to pull-down assays using protein extracts from AD and control prefrontal cortex tissues. Aβ-interacting proteins were identified by proteomics. Their dysregulation was assessed in AD tissue samples and a cellular AD model by WB, immunocytochemistry, in silico, and immunohistochemistry. We identified 185 and 874 proteins associated with Aβ40- and Aβ42-fibrils, respectively, with 78 in common. Sixteen were validated as interactors by WB and ex vivo as components of Aβ plaques by IF, displaying altered expression in AD and supporting a functional role for PRKCG in amyloidogenesis, as its modulation alters Aβ fibril formation. This study expands the Aβ plaque-associated proteome characterization, identifies novel fibril interactors, and highlight potential therapeutic targets, as the modulation of PRKCG prevent or reduce Aβ plaque formation in AD.
2026-01-24 | PXD061100 | Pride
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:Extracellular matrix (ECM) remodeling is strongly linked to Alzheimer’s disease (AD) risk, but its functions are not fully understood. Here, we found that medial prefrontal cortex (mPFC) injection with chondroitinase ABC (ChABC) to remodel ECM reverses short-term memory loss and reduces Aβ deposition in 5xFAD mice. ECM remodeling also reactivates astrocytes, untangles aggrecan’s entanglement with amyloid-beta (Aβ) plaques, and encourages astrocyte recruitment to the surrounding plaques. ECM remodeling promotes astrocyte phagocytosis of Aβ plaque by activating the astrocyte phagocytosis receptor mertk and astrocytic vesicle circulation. Importantly, ECM remodeling enhances the autophagy-lysosome pathway in astrocytes to mediate Aβ clearance and alleviate AD pathology. Our work thus discovers a cellular mechanism to remodel the ECM to active astrocyte autophagic lysosomal pathway alleviation AD pathology. It may represent a potential therapeutic strategy and serve as a hallmark for treating AD.
2024-10-17 | PXD046784 | Pride
Project description:Imbalanced production and clearance of amyloid-β (Aβ) is a hallmark pathological feature of Alzheimer’s disease (AD). While several monoclonal antibodies targeting Aβ have shown reductions in amyloid burden, their impact on cognitive function remains controversial, with the added risk of inflammatory side effects. Dysregulated stimulator of interferon genes (STING) signaling is implicated in neurodegenerative disorders, yet the biological interaction between this pathway and Aβ, as well as their combined influence on AD progression, is poorly understood. Here we show that while microglia play a protective role in clearing extracellular Aβ, excessive Aβ engulfment triggers the cytosolic leakage of mitochondrial DNA for cGAS-STING cascade. This creates a negative feedback loop that not only exacerbates neuroinflammation but also impairs further Aβ clearance. To address this, we present a nanomedicine approach termed “Aβ-STING Synergistic ImmunoSilencing Therapy (ASSIST)”. ASSIST comprises STING inhibitors encapsulated within a blood-brain barrier (BBB)-permeable polymeric micelle that also serves as an Aβ scavenger. Through a multivalent mechanism, ASSIST efficiently destabilizes Aβ plaques and prevents monomer aggregation, subsequently promoting the engulfment of the dissociated Aβ by microglia rather than neurocytes. Furthermore, the STING signaling induced by excessive Aβ uptake is blocked, reducing inflammation and restoring microglial homeostatic functions involved in Aβ clearance. Intravenous administration of ASSIST significantly reduces Aβ burden and improves cognition in AD mice, with minimal cerebral amyloid angiopathy or microhemorrhages. We provide a proof-of-concept nanoengineering strategy to target the maladaptive immune feedback loop arising from conventional immunotherapy for AD treatment.
2025-05-09 | GSE285608 | GEO
Project description:Microglia impact brain development, homeostasis, and pathology. One important microglial function in Alzheimer’s Disease (AD) is to contain proteotoxic amyloid β (Aβ) plaques. Recent studies reported the involvement of autophagy-related (ATG) proteins in this process. Here we found that microglia-specific deletion of Atg7 in an AD mouse model impaired microglia coverage of Aβ plaques, increasing plaque diffusion and neurotoxicity. Single-cell RNA sequencing, biochemical and immunofluorescence analyses revealed that Atg7 deficiency reduces unfolded protein response (UPR) while increasing oxidative stress. Cellular assays demonstrated that these changes lead to lipoperoxidation and ferroptosis of microglia. In aged mice without Aβ build-up, UPR reduction and increase oxidative damage induced by Atg7 deletion did not impact microglia numbers. We conclude that reduced UPR and increased oxidative stress in Atg7-deficient microglia lead to ferroptosis when exposed to proteotoxic stress from Aβ plaques. However, these microglia can still manage misfolded protein accumulation as they age.
2025-01-30 | GSE286094 | GEO
Project description:Microglia impact brain development, homeostasis, and pathology. One important microglial function in Alzheimer’s Disease (AD) is to contain proteotoxic amyloid β (Aβ) plaques. Recent studies reported the involvement of autophagy-related (ATG) proteins in this process. Here we found that microglia-specific deletion of Atg7 in an AD mouse model impaired microglia coverage of Aβ plaques, increasing plaque diffusion and neurotoxicity. Single-cell RNA sequencing, biochemical and immunofluorescence analyses revealed that Atg7 deficiency reduces unfolded protein response (UPR) while increasing oxidative stress. Cellular assays demonstrated that these changes lead to lipoperoxidation and ferroptosis of microglia. In aged mice without Aβ build-up, UPR reduction and increase oxidative damage induced by Atg7 deletion did not impact microglia numbers. We conclude that reduced UPR and increased oxidative stress in Atg7-deficient microglia lead to ferroptosis when exposed to proteotoxic stress from Aβ plaques. However, these microglia can still manage misfolded protein accumulation as they age.
2025-01-30 | GSE286095 | GEO