Tau promotes neurodegeneration through global chromatin relaxation
Ontology highlight
ABSTRACT:
ORGANISM(S): Drosophila melanogaster
PROVIDER: GSE53719 | GEO | 2013/12/31
SECONDARY ACCESSION(S): PRJNA232714
REPOSITORIES: GEO
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Project description:We performed H3K9me2-based ChIP-seq to identify regions of the Drosophila genome that are H3K9me2-depleted due to transgenic neuronal expression of human mutant tau. Examination of H3K9me2 histone methylation in 10 day old control and tau transgenic Drosophila heads.
2013-12-31 | E-GEOD-53719 | biostudies-arrayexpress
Project description:The microtubule-associated protein tau is involved in a number of neurodegenerative disorders, including Alzheimer's disease. Previous studies have linked oxidative stress and subsequent DNA damage to neuronal death in Alzheimer's disease and related tauopathies. Given that DNA damage can substantially alter chromatin structure, we examined epigenetic changes in tau-induced neurodegeneration. We found widespread loss of heterochromatin in tau transgenic Drosophila and mice and in human Alzheimer's disease. Notably, genetic rescue of tau-induced heterochromatin loss substantially reduced neurodegeneration in Drosophila. We identified oxidative stress and subsequent DNA damage as a mechanistic link between transgenic tau expression and heterochromatin relaxation, and found that heterochromatin loss permitted aberrant gene expression in tauopathies. Furthermore, large-scale analyses from the brains of individuals with Alzheimer's disease revealed a widespread transcriptional increase in genes that were heterochromatically silenced in controls. Our results establish heterochromatin loss as a toxic effector of tau-induced neurodegeneration and identify chromatin structure as a potential therapeutic target in Alzheimer's disease.
| S-EPMC4012297 | biostudies-literature
Project description:In addition to tau and Aβ pathologies, inflammation plays an important role in Alzheimer's disease (AD). Variants in APOE and TREM2 increase AD risk. ApoE4 exacerbates tau-linked neurodegeneration and inflammation in P301S tau mice and removal of microglia blocks tau-dependent neurodegeneration. Microglia adopt a heterogeneous population of transcriptomic states in response to pathology, at least some of which are dependent on TREM2. Previously, we reported that knockout (KO) of TREM2 attenuated neurodegeneration in P301S mice that express mouse Apoe. Because of the possible common pathway of ApoE and TREM2 in AD, we tested whether TREM2 KO (T2KO) would block neurodegeneration in P301S Tau mice expressing ApoE4 (TE4), similar to that observed with microglial depletion. Surprisingly, we observed exacerbated neurodegeneration and tau pathology in TE4-T2KO versus TE4 mice, despite decreased TREM2-dependent microgliosis. Our results suggest that tau pathology-dependent microgliosis, that is, TREM2-independent microgliosis, facilitates tau-mediated neurodegeneration in the presence of ApoE4.
2022-11-30 | GSE206368 | GEO
Project description:One of the defining pathological features of Alzheimer’s Disease (AD) is the deposition of neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau in the brain. Aberrant activation of kinases in AD has been suggested to enhance phosphorylation and toxicity of tau, making the responsible tau kinases attractive therapeutic targets. The full complement of tau interacting kinases in AD brain and their activity in disease remains incompletely defined. Here, immunoaffinity enrichment coupled with mass spectrometry (MS) identified TANK-binding kinase 1 (TBK1) as a tau-interacting partner in human AD cortical brain tissues. We validated this interaction in human AD, familial frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17) caused by mutations in MAPT (R406W & P301L) and corticobasal degeneration (CBD) postmortem brain tissues as well as human cell lines. Further, we document increased TBK1 activation in both AD and FTDP-17 and map TBK1 phosphorylation sites on tau based on in vitro kinase assays coupled to MS. Lastly, in a Drosophila tauopathy model, activating expression of a conserved TBK1 ortholog triggers tau hyperphosphorylation and enhanced neurodegeneration, whereas knockdown had the reciprocal effect, suppressing tau toxicity. Collectively, our findings suggest that increased TBK1 activation may promote tau hyperphosphorylation and neuronal loss in AD and related tauopathies.
2022-03-01 | PXD025301 | Pride
Project description:Tau aggregates lead to progressive neurodegeneration in Alzheimer’s disease (AD). Neuron death is one of the hallmarks of neurodegeneration.However, the pathological influence of neuronal death is undetermined, and the connection between Tau aggregates and neuronal death remains elusive. Here we demonstrated the essential role of neuron death in Tau-related neurodegeneration. Tau-neurons died in necroptosis, dependent on ZBP1 sensitized by Z-RNAs (an unusual left-handed conformation). Those endogenous Z-RNAs were transcripts of reactivated transposable elements (TEs) originally silenced in heterochromatin.
2023-11-22 | GSE248069 | GEO
Project description:Tau aggregates lead to progressive neurodegeneration in Alzheimer’s disease (AD) (ref). Neuron death is one of the hallmarks of neurodegeneration (ref). However, the pathological influence of neuronal death is undetermined, and the connection between Tau aggregates and neuronal death remains elusive. Here we demonstrated the essential role of neuron death in Tau-related neurodegeneration. Tau-neurons died in necroptosis, dependent on ZBP1 sensitized by Z-RNAs (an unusual left-handed conformation). Those endogenous Z-RNAs were transcripts of reactivated transposable elements (TEs) originally silenced in heterochromatin.
2023-11-22 | GSE248068 | GEO
Project description:Tau aggregates lead to progressive neurodegeneration in Alzheimer’s disease (AD) (ref). Neuron death is one of the hallmarks of neurodegeneration (ref). However, the pathological influence of neuronal death is undetermined, and the connection between Tau aggregates and neuronal death remains elusive. Here we demonstrated the essential role of neuron death in Tau-related neurodegeneration. Tau-neurons died in necroptosis, dependent on ZBP1 sensitized by Z-RNAs (an unusual left-handed conformation). Those endogenous Z-RNAs were transcripts of reactivated transposable elements (TEs) originally silenced in heterochromatin.
2023-11-22 | GSE248067 | GEO
Project description:The type III RNase Dicer is responsible for the maturation and function of microRNA (miRNA) molecules in the cell. It is now well documented that Dicer and the fine-tuning of the miRNA gene network are important for neuronal integrity. However, the underlying mechanisms involved in neuronal death, particularly in the adult brain, remain poorly defined. Here, we show that absence of Dicer in the adult forebrain is accompanied by a mixed neurodegenerative phenotype. While neuronal loss is observed in the hippocampus, cellular shrinkage is predominant in the cortex. Interestingly, neuronal degeneration coincides with the hyperphosphorylation of endogenous tau at several epitopes previously associated with neurofibrillary pathology. Transcriptome analysis of enzymes involved in tau phosphorylation identified ERK1 as one of the candidate kinases responsible for this event in vivo. We further demonstrate that miRNAs belonging to the miR-15 family are potent regulators of ERK1 expression in mouse neuronal cells and co-expressed with ERK1/2 in vivo. Last, we show that miR-15a is specifically downregulated in Alzheimer’s disease brain. In sum, these results support the hypothesis that changes in the miRNA network may contribute to a neurodegenerative phenotype by affecting tau phosphorylation. Dicer KO vs. control
2010-08-28 | E-GEOD-23847 | biostudies-arrayexpress
Project description:Transposable elements, known colloquially as “jumping genes,” constitute approximately 45% of the human genome. Cells utilize epigenetic defenses to limit transposable element jumping, including formation of silencing heterochromatin and generation of piwi-interacting RNAs (piRNAs), small RNAs that facilitate clearance of transposable element transcripts. Here we identify transposable element activation as a key mediator of neuronal death in tauopathies, a group of neurodegenerative disorders, including Alzheimer’s disease, that are pathologically characterized by deposits of tau protein in the brain. Mechanistically, we find that heterochromatin decondensation and reduction of piwi/piRNAs drive transposable element activation in tauopathy. Using genetic and pharmacological approaches in a Drosophila melanogaster model of tauopathy, we provide evidence for a causal relationship between pathogenic tau-induced heterochromatin decondensation, piwi/piRNA depletion, active transposable element obilization, and neurodegeneration. We further report a significant increase in transcripts of the endogenous retrovirus class of transposable elements in human Alzheimer’s disease and progressive supranuclear palsy, suggesting that transposable element dysregulation is conserved in human tauopathy. Taken together, our data identify heterochromatin decondensation, piwi/piRNA depletion and consequent transposable element activation as a novel, pharmacologically targetable, mechanistic driver of neurodegeneration in tauopathy.
2018-07-04 | GSE115606 | GEO
Project description:APOE is the strongest genetic risk factor for late-onset Alzheimer’s disease. ApoE exacerbates tau-associated neurodegeneration by driving microglial activation. However, how apoE regulates microglial activation and whether targeting apoE is therapeutically beneficial in tauopathy is unclear. Here we show that overexpressing a low-density lipoprotein receptor (LDLR) transgene in P301S tau transgenic mice markedly reduces brain apoE and ameliorates tau pathology and neurodegeneration. ApoE specifically interacts with a high-molecular-weight tau species, and highly correlates with phospho-tau and insoluble tau levels. Microglial expression of the LDLR transgene reduces intracellular apoE and is associated with less microglial activation. snRNA-seq analysis of apoE-deficient or LDLR-overexpressing brains reveals that apoE deficiency drives microglial catabolism and increases the oligodendrocyte progenitor cell population. LDLR overexpression shares overlapping mechanisms, but uniquely upregulates microglial expression of specific ion channels and neurotransmitter receptors in tauopathy. A subset of disease-associated astrocytes with both neuroprotective and neurotoxic gene signatures is also identified.
2021-02-06 | GSE166261 | GEO