Z-RNA drives Tau-mediated neurodegeneration of Alzheimer’s disease [RNA-Seq]
Ontology highlight
ABSTRACT: 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.
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.
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.
Project description:Pathogenic a-synuclein and tau are critical drivers of neurodegeneration and their mutations cause neuronal loss in patients. Whether the underlying preferential neuronal vulnerability is a cell-type intrinsic property or a consequence of increased expression levels remains elusive. Here, we explore cell-type specific a-synuclein and tau expression in human brain datasets and use deep phenotyping as well as brain- wide single-cell RNA sequencing of >200 live neuron types in fruit flies to ask which cellular environments react most to a-synuclein or tau toxicity. We detect phenotypic and transcriptomic evidence of differential neuronal vulnerability independent of a-synuclein or tau expression levels. Comparing vulnerable with resilient neurons in Drosophila enabled us to predict numerous human neuron subtypes with increased intrinsic susceptibility to pathogenic a-synuclein or tau. By uncovering synapse and Ca2+ homeostasis related genes as tau toxicity modifiers our work paves the way to leverage neuronal identity to uncover modifiers of neurodegeneration-associated toxic proteins.
Project description:We report the isolation and sequencing of tau aggregates from [1] HEK293 cells expressing Tau-RD-P301S-CFP/YFP that have been seeded with preformed fibrils from the brain of P301S mice (B6-Tg(Thy1-MAPT*P301S)2541; referred to as Tg2541 mice). Tau aggregates were isolated by differential centrifugation followed by fluorescence automated particle sorting using a BD FACSaraia. We found that these tau aggregates were enriched for particular small non-coding RNAs, including snoRNAs and snRNAs. [2] the following mice: FvBB6F1-Tg(Camk2a-tTa),(tetO-MAPT*wt)21221 (referred to as rTg21221 or WT tau mice in the paper) and FvBB6F1-Tg(Camk2a-tTA)1Mmay, (tet)-tdTomato-Syp/EGFP)1.1Luo/J,(tetO-MAPT*P301L)4510 (referred to as rTg4510 or P301L mice in the paper). Briefly, tau aggregates were isolated by 1% sarkosyl extraction (to enrich for insoluble proteins) followed by immunoprecipitation of tau using the tau-12 antibody (see Methods section of associated paper for further details). We found that these tau aggregates were enriched for particular small non-coding RNAs, including snRNAs and some snoRNAs. [3] Sequencing of HEK293 tau biosensor cells with and without tau aggregates reveals evidence of significant splicing alterations. Specifically we observed an increase in intron retention events in cells that contain tau aggregates relative to cells without tau aggregates.
Project description:Clarke2000 - One-hit model of cell death in
neuronal degenerations
This one-hit model fits different
neuronal-death associated diseases for different animal
models.
This model is described in the article:
A one-hit model of cell
death in inherited neuronal degenerations.
Clarke G, Collins RA, Leavitt BR,
Andrews DF, Hayden MR, Lumsden CJ, McInnes RR.
Nature 2000 Jul; 406(6792):
195-199
Abstract:
In genetic disorders associated with premature neuronal
death, symptoms may not appear for years or decades. This delay
in clinical onset is often assumed to reflect the occurrence of
age-dependent cumulative damage. For example, it has been
suggested that oxidative stress disrupts metabolism in
neurological degenerative disorders by the cumulative damage of
essential macromolecules. A prediction of the cumulative damage
hypothesis is that the probability of cell death will increase
over time. Here we show in contrast that the kinetics of
neuronal death in 12 models of photoreceptor degeneration,
hippocampal neurons undergoing excitotoxic cell death, a mouse
model of cerebellar degeneration and Parkinson's and
Huntington's diseases are all exponential and better explained
by mathematical models in which the risk of cell death remains
constant or decreases exponentially with age. These kinetics
argue against the cumulative damage hypothesis; instead, the
time of death of any neuron is random. Our findings are most
simply accommodated by a 'one-hit' biochemical model in which
mutation imposes a mutant steady state on the neuron and a
single event randomly initiates cell death. This model appears
to be common to many forms of neurodegeneration and has
implications for therapeutic strategies.
This model is hosted on
BioModels Database
and identified by:
BIOMD0000000538.
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BioModels Database:
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quantitative kinetic models.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to
the public domain worldwide. Please refer to
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Project description:Alzheimer’s disease (AD) is the most prevalent form of neurodegeneration. Despite the well-established link between tau aggregation and clinical progression, the major pathways driven by this protein to intrinsically damage neurons are incompletely understood. To model AD-relevant neurodegeneration driven by tau, we overexpressed non-mutated human tau in primary mouse neurons and observed substantial axonal degeneration and cell death, a process accompanied by activated caspase 3. Mechanistically, we detected deformation of the nuclear envelope and increased DNA damage response in tau-expressing neurons. Gene profiling analysis further revealed significant alterations in the mitogen-activated protein kinase (MAPK) pathway; moreover, inhibitors of dual leucine zipper kinase (DLK) and c-Jun N-terminal kinase (JNK) were effective in alleviating wild-type human tau-induced neurodegeneration. In contrast, mutant P301L human tau was less toxic to neurons, despite causing comparable DNA damage. Axonal DLK activation induced by wild-type tau potentiated the impact of DNA damage response, resulting in overt neurotoxicity. In summary, we have established a cellular tauopathy model highly relevant to AD and identified a functional synergy between the MAPK-DLK axis and DNA damage response in the neuronal degenerative process.
Project description:Selective neurodegeneration is a critical causal factor in Alzheimer’s disease (AD); however, the mechanisms that lead some neurons to perish while others remain resilient are unknown. We sought potential drivers of this selective vulnerability using single-nucleus RNA sequencing and discovered that apoE expression level is a substantial driver of neuronal variability. Strikingly, neuronal expression of apoE—which has a robust genetic linkage to AD—correlated strongly, on a cell-by-cell basis, with immune response pathways in neurons in the brains of wildtype mice, human apoE knock-in mice, and humans with or without AD. Elimination or over-expression of neuronal apoE revealed a causal relationship between apoE expression, neuronal MHC-I expression, Tau pathology, and neurodegeneration. Functional reduction of MHC-I ameliorated Tau pathology in apoE4-expressing primary neurons and in mouse hippocampi expressing pathological Tau. These findings suggest a mechanism linking neuronal apoE expression to MHC-I expression and, subsequently, to Tau pathology and selective neurodegeneration.
Project description:Neuroinflammatory processes are a prominent contributor to the pathology of Parkinson’s disease (PD), characterized by the progressive loss of dopaminergic neurons in the substantia nigra (SN) and deposits of α-synuclein aggregates. MLKL-mediated cell necroptosis might occur in the onset of PD and lead to neuronal dopaminergic degeneration. However, the link between α-synuclein, neuroinflammatory processes, and neurodegeneration in PD remains unclear. Here, our in vitro study indicated that inhibition of MLKL exerted a protective effect against 6-OHDA- and TNF-α-induced neuronal cell death. Furthermore, we created a mouse model (Tg-Mlkl-/-) with typical progressive Parkinson traits by crossbreeding SNCA A53T transgenic mice with MLKL knockout mice. Tg-Mlkl-/ mice displayed dramatically improved motor symptoms and reduced hyperphosphorylated α-synuclein expression. More data suggested that MLKL deficiency protected dopaminergic neurons, blocked neuronal cell death, and attenuated neuroinflammation by inhibiting the activation of the microglia and astrocytes. Single-cell RNA-seq analysis revealed reduced microglial cells and damped neuron death in the SN of the Tg-Mlkl-/- mice. Subcluster analysis identified a unique cell type-specific transcriptome profiling in the MLKL deficiency mice. Thus, MLKL represents a critical therapeutic target for reducing neuroinflammation and preventing dopaminergic neuron degeneration.
Project description:The roles of long noncoding RNAs (lncRNAs) in synaptic transmission and neuronal development are emerging. Here we applied an integrated bioinformatic/biological screening strategy to identify lncRNAs that regulate synaptic vesicle release. We identified neuroLNC, a conserved neuron-specific nuclear lncRNA that modulates synaptic vesicle release, presynaptic calcium influx, neurite elongation and neuronal migration. In neurons neuroLNC interacts with a neurodegeneration-associated protein and tunes a set of presynaptic transcripts implicated in neurotransmitter release.
Project description:Abnormally accumulated tau protein aggregates are one of the hallmarks of dementia, including Alzheimer’s disease (AD), and are believed to play a critical role in neurodegeneration. In order to investigate proteomic alteration driven by tau aggregates, we implemented quantitative proteomics to analyze disease model mice expressing human MAPTP301S transgene (hTau-Tg) and quantified more than 9,000 proteins in total. We applied the weighted gene co-expression analysis (WGCNA) algorithm to the datasets and explored protein co-expression modules that were associated with the accumulation of tau aggregates and were preserved in proteomes of AD brains. This led us to identify four modules with functions related to neuroinflammatory responses, mitochondrial energy production processes (including the tricarboxylic acid cycle and oxidative phosphorylation), cholesterol biosynthesis, and postsynaptic density. Furthermore, a phosphoproteomics study uncovered phosphorylation sites that were highly correlated with these modules. Our datasets represent resources for understanding the molecular basis of tau-induced neurodegeneration, including AD.