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PROVIDER: PRJNA1203289 | ENA |
REPOSITORIES: ENA
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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
Project description:Loss of ATG7 in Microglia Impairs UPR, Triggers Ferroptosis and Weakens Amyloid Pathology Control [scRNA-seq]
| PRJNA1207905 | ENA
Project description:Microglia are phagocytic cells that survey the brain and perform neuroprotective functions in response to tissue damage, but their activating receptors are largely unknown. Triggering receptor expressed on myeloid cells 2 (TREM2) is a microglial immunoreceptor whose loss-of-function mutations in humans cause presenile dementia, while genetic variants are associated with increased risk of neurodegenerative diseases. In myeloid cells, TREM2 has been involved in the regulation of phagocytosis, cell proliferation and inflammatory responses in vitro. However, it is unknown how TREM2 contributes to microglia function in vivo. Here, we identify a critical role for TREM2 in the activation and function of microglia during cuprizone (CPZ)-induced demyelination. TREM2-deficient (TREM2(-/-)) mice had defective clearance of myelin debris and more axonal pathology, resulting in impaired clinical performances compared to wild-type (WT) mice. TREM2(-/-) microglia proliferated less in areas of demyelination and were less activated, displaying a more resting morphology and decreased expression of the activation markers MHC II and inducible nitric oxide synthase as compared to WT. Mechanistically, gene expression and ultrastructural analysis of microglia suggested a defect in myelin degradation and phagosome processing during CPZ intoxication in TREM2(-/-) microglia. These findings place TREM2 as a key regulator of microglia activation in vivo in response to tissue damage. Two STAGE (6weeks 12 weeks),
2015-07-06 | E-GEOD-70475 | biostudies-arrayexpress
Project description:Recessive mutations in DNACJ3, an endoplasmic reticulum (ER)-resident BiP co-chaperone, have been identified in patients with multisystemic neurodegeneration and diabetes mellitus. While minor ER morphology changes due to loss of DNAJC3 have been reported previously, the precise cellular pathophysiology is still elusive and not well understood. To further elucidate the cellular consequences of DNAJC3 loss we employed a non-biased proteomic approach and identified dysregulation of several key cellular pathways implying a pathophysiological interplay of perturbed lipid metabolism, mitochondrial bioenergics, ER-Golgi function and amyloid-beta processing. Further functional investigations in fibroblasts of patients with DNAJC3 mutations detected cellular accumulation of lipids, and an increased sensitivity to cholesterol-stress, which led to activation of the UPR, alterations of the ER-Golgi machinery, a defect of APP processing and concomitant Aβ accumulation. Moreover, we described here for the first-time alterations in mitochondrial morphology and oxidative phosphorylation as a major contributor to the DNAJC3 pathophysiology. Hence, we propose that the loss of DNAJC3 affects the lipid/cholesterol homeostasis, leading to UPR activation, Aβ accumulation and impaired protection against mitochondrial oxidative stress.
2021-07-17 | PXD027372 | panorama
Project description:Alzheimer’s disease (AD) is the most prevalent form of dementia and is characterized by abnormal extracellular aggregates of amyloid-b and intraneuronal hyperphosphorylated, tau tangles and neuropil threads. Microglia, the tissue-resident macrophages of the central nervous system (CNS), are important for CNS homeostasis and implicated in AD pathology. In amyloid mouse models, a phagocytic/activated microglia phenotype has been identified. How increasing levels of amyloid-b and tau pathology affect human microglia transcriptional profiles is unknown. Here, we performed snRNAseq on 482,472 nuclei from non-demented control brains and AD brains containing only amyloid-b plaques or both amyloid-b plaques and tau pathology. Within the microglia population, distinct expression profiles were identified of which two were AD pathology-associated. The phagocytic/activated AD1-microglia population abundance strongly correlated with tissue amyloid-b load and localized to amyloid-b plaques. The AD2-microglia abundance strongly correlated with tissue phospho-tau load and these microglia were more abundant in samples with over tau pathology. This full characterization of human disease associated microglia phenotypes provides new insights in the pathophysiological role of microglia in AD and offers new targets for microglia-state-specific therapeutic strategies.
2021-02-20 | GSE148822 | GEO
Project description:Loss-of-function mutations in TREM2 (triggering receptor expressed on myeloid cells 2) strongly increase Alzheimer’s disease (AD) risk. Preclinical models using Trem2 deletion or overexpression have revealed a protective Trem2 function related to β-amyloid accumulation, a process that is most prominent during the pre-diagnosis stages of AD. The role of TREM2 in later AD stages characterized by tau-mediated neurodegeneration is less clear. To understand Trem2 function in the context of both β-amyloid and tau pathologies, we examined Trem2-deficient mice expressing mutant tau alone (pR5-183 model) or in the TauPS2APP model, in which β-amyloid pathology exacerbates tau pathology and neurodegeneration. Single-cell RNA-sequencing in these models revealed robust disease-associated microglia (DAM) activation in TauPS2APP mice that was both amyloid-dependent and Trem2-dependent. In the presence of β-amyloid pathology, Trem2 deletion further exacerbated tau accumulation and spreading and promoted brain atrophy. Without β-amyloid pathology, Trem2 deletion did not affect these processes. Therefore, TREM2 may slow AD progression and reduce tau-driven neurodegeneration by restricting the degree to which β-amyloid facilitates the spreading of pathogenic tau
2021-02-24 | GSE153895 | GEO
Project description:Here we studied cellular level changes of hippocampal cells by unbiased single cell RNA-seq using AD mouse models bearing amyloid pathology (PS2APP), or amyloid and tau combined pathology (TauPS2APP) by single cell RNA-seq. We identified 16 different cell types and further characterized responses of microglia, oligodendrocytes, astrocytes and T cells to amyloidosis only and amyloid plus tau combined pathology. Both mouse models exhibited robust microglial responses. We also found distinct responses of oligodendrocytes to different AD pathologies. We observed increased T cell numbers in both mouse models. Current dataset presents diverse transcriptomic responses to AD pathology and provides resources to study molecular mechanisms underlying disease onset and progression.
2021-11-12 | GSE181786 | GEO
Project description:Microglia-mediated neuroinflammation has been implicated in the pathogenesis of Alzheimer's disease (AD). Although microglia in aging and neurodegenerative disease model mice show a loss of homeostatic phenotype and activation of disease-associated microglia (DAM), a correlation between those phenotypes and the degree of neuronal cell loss has not been clarified. In this study, we performed RNA sequencing of microglia isolated from three representative neurodegenerative mouse models, AppNL-G-F/NL-G-F with amyloid pathology, rTg4510 with tauopathy, and SOD1G93A with motor neuron disease by magnetic activated cell sorting. In parallel, gene expression patterns of the human precuneus with early Alzheimer's change (n=11) and control brain (n=14) were also analyzed by RNA sequencing. We found that a substantial reduction of homeostatic microglial genes in rTg4510 and SOD1G93A microglia, whereas DAM genes were uniformly upregulated in all mouse models. The reduction of homeostatic microglial genes was correlated with the degree of neuronal cell loss. In human precuneus with early AD pathology, reduced expression of genes related to microglia- and oligodendrocyte-specific markers was observed, although the expression of DAM genes was not upregulated. Our results implicate a loss of homeostatic microglial function in the progression of AD and other neurodegenerative diseases. Moreover, analyses of human precuneus also suggest loss of microglia and oligodendrocyte functions induced by early amyloid pathology in human.
2023-07-09 | GSE236268 | GEO
Project description:Autophagy is a mechanism that regulates cellular metabolism and clearance of damaged macromolecules and organelles. Impaired degradation of modified macromolecules contributes to cellular dysfunction and is observed in aged tissue and senescent cells. We have inactivated Atg7, an essential autophagy gene, in murine keratinocytes and have found in an earlier study that this resulted in increased baseline oxidative stress and reduced capacity to degrade crosslinked proteins after oxidative ultraviolet stress. To investigate whether autophagy deficiency would promote cellular aging, we studied, how Atg7 deficient (KO) and Atg7 bearing cells (WT) would respond to stress induced by Paraquat (PQ), an oxidant drug commonly used to induce cellular senescence.
2017-02-14 | GSE84935 | GEO