MTOR-dependent translation amplifies microglia priming in ageing
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ABSTRACT:
PROVIDER: PRJNA658992 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR12508040_1.fastq.gz | Fastqsanger.gz | |||
| SRR12508040_2.fastq.gz | Fastqsanger.gz | |||
| SRR12508041_1.fastq.gz | Fastqsanger.gz | |||
| SRR12508041_2.fastq.gz | Fastqsanger.gz | |||
| SRR12508042_1.fastq.gz | Fastqsanger.gz |
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Project description:Microglia maintain homeostasis in the brain. However, with age, they become primed and respond more strongly to inflammatory stimuli. We show here that microglia from aged mice upregulated mammalian target of rapamycin (mTOR) complex 1 signaling regulating translation, as well as cytokine protein levels. Genetic ablation of mTOR signaling showed a dual, yet contrasting effect on microglia priming: it caused an NF-kB-dependent upregulation of priming genes at mRNA level; however, mice displayed reduced cytokine protein levels, diminished microglia activation and milder sickness behavior. The effect on translation was dependent on reduced phosphorylation of 4EBP1 and increased 4EBP1 expression, resulting in decreased binding of EIF4E to EIF4G. Similar changes were present in aged human microglia and in damage-associated microglia, indicating upregulation of mTOR-dependent translation is an essential step licensing microglia priming in ageing and neurodegeneration.
2021-07-30 | GSE156762 | GEO
Project description:Microglia maintain homeostasis in the brain. However, with age, they become primed and respond more strongly to inflammatory stimuli. We show here that microglia from aged mice had upregulated mTOR complex 1 signaling controlling translation, as well as protein levels of inflammatory mediators. Genetic ablation of mTOR signaling showed a dual yet contrasting effect on microglia priming: it caused an NF-κB-dependent upregulation of priming genes at the mRNA level; however, mice displayed reduced cytokine protein levels, diminished microglia activation, and milder sickness behavior. The effect on translation was dependent on reduced phosphorylation of 4EBP1, resulting in decreased binding of eIF4E to eIF4G. Similar changes were present in aged human microglia and in damage-associated microglia, indicating that upregulation of mTOR-dependent translation is an essential aspect of microglia priming in aging and neurodegeneration.
| S-EPMC7773382 | biostudies-literature
Project description:mTOR regulates mRNA translation. Whereas ribosome-profiling suggested that mTOR exclusively stimulates translation of TOP (containing a 5â-terminal oligopyrimidine [5âTOP] motif) and TOP-like mRNAs, polysome-profiling implied that mTOR also modulates translation of non-TOP mRNAs. We show that ribosome-, but not polysome-profiling, is biased towards identification of TOP mRNAs as differentially translated while obscuring detection of changes in non-TOP mRNA translation. Transcription start site profiling by Nano-Cap Analysis of Gene Expression (nanoCAGE) revealed that many mTOR-sensitive mRNAs do not have 5âTOP motifs. Moreover, nanoCAGE showed that 5â UTR features distinguish two functionally and translationally distinct subsets of mTOR-sensitive mRNAs: i) those with short 5â UTRs enriched for mitochondrial functions such as respiration, that are translated in an eIF4E, but not eIF4A1-dependent manner and ii) mRNAs encoding proliferation- and survival-promoting proteins, that harbor long 5â UTRs, and require both eIF4E and eIF4A1 for their efficient translation. Selective inhibition of translation of mRNAs harboring long 5â UTRs via suppression of eIF4A leads to uncoupling of expression of proteins involved in respiration (e.g. ATP5O) from those protecting mitochondrial integrity (e.g. BCL-2) ultimately resulting in apoptosis. Conversely, simultaneous translational downregulation of both long and short 5â UTR mRNAs by mTOR inhibitors results in suppression of mitochondrial respiration and predominantly cytostatic effects. Therefore, 5â UTR features define differential modes of translation of functionally distinct mTOR-sensitive mRNAs, which explains discrepancies between the effects of mTOR and eIF4A inhibitors on neoplastic cells. Determination of 5'UTR lengths using nanoCAGE in MCF7 cells
2016-03-14 | E-GEOD-77033 | biostudies-arrayexpress
Project description:T cells receive numerous positive and negative signals during primary antigen encounter that control their proliferation and function, but how these signals are integrated to modulate T cell memory has not been fully characterized. In these studies, we demonstrate that combining seemingly opposite signals, CTLA-4 blockade and rapamycin-mediated mTOR inhibition, during in vivo T cell priming leads to both an increase in the frequency of memory CD8+ T cells and improved memory responses to tumors and bacterial challenges. This enhanced efficacy corresponds to increased early expansion and memory precursor differentiation of CD8+ T cells and increased mitochondrial biogenesis and spare respiratory capacity in memory CD8+ T cells in mice treated with anti-CTLA-4 and rapamycin during immunization. Collectively, these results reveal that mTOR inhibition cooperates with rather than antagonizes blockade of CTLA-4, promoting unrestrained effector function and proliferation and an optimal metabolic program for CD8+ T cell memory. Total RNA was isolated from FACS-sorted, antigen-specific CD8+T cells from different treatment conditions at 5 or 35 days after primary T cell activation
2015-01-31 | E-GEOD-63022 | biostudies-arrayexpress
Project description:mTOR regulates mRNA translation. Whereas ribosome-profiling suggested that mTOR exclusively stimulates translation of TOP (containing a 5’-terminal oligopyrimidine [5’TOP] motif) and TOP-like mRNAs, polysome-profiling implied that mTOR also modulates translation of non-TOP mRNAs. We show that ribosome-, but not polysome-profiling, is biased towards identification of TOP mRNAs as differentially translated while obscuring detection of changes in non-TOP mRNA translation. Transcription start site profiling by Nano-Cap Analysis of Gene Expression (nanoCAGE) revealed that many mTOR-sensitive mRNAs do not have 5’TOP motifs. Moreover, nanoCAGE showed that 5’ UTR features distinguish two functionally and translationally distinct subsets of mTOR-sensitive mRNAs: i) those with short 5’ UTRs enriched for mitochondrial functions such as respiration, that are translated in an eIF4E, but not eIF4A1-dependent manner and ii) mRNAs encoding proliferation- and survival-promoting proteins, that harbor long 5’ UTRs, and require both eIF4E and eIF4A1 for their efficient translation. Selective inhibition of translation of mRNAs harboring long 5’ UTRs via suppression of eIF4A leads to uncoupling of expression of proteins involved in respiration (e.g. ATP5O) from those protecting mitochondrial integrity (e.g. BCL-2) ultimately resulting in apoptosis. Conversely, simultaneous translational downregulation of both long and short 5’ UTR mRNAs by mTOR inhibitors results in suppression of mitochondrial respiration and predominantly cytostatic effects. Therefore, 5’ UTR features define differential modes of translation of functionally distinct mTOR-sensitive mRNAs, which explains discrepancies between the effects of mTOR and eIF4A inhibitors on neoplastic cells.
2016-03-14 | GSE77033 | GEO
Project description:The PI3K-Akt-mTOR signaling pathway is a master regulator of RNA translation. Pharmacological inhibition of this pathway preferentially and coordinately suppresses, in a 4EBP1/2-dependent manner, translation of mRNAs encoding ribosomal proteins. However, it remains unclear whether mTOR-4EBP1/2 is the exclusive translational regulator of this group of genes, and furthermore, systematic searches for novel translational modulators have been immensely challenging due to difficulties in scaling existing RNA translation profiling assays. Here, we developed a rapid and highly scalable approach for gene-specific quantitation of RNA translation, termed Targeted Profiling of RNA Translation (TPRT). We applied this technique in a chemical screen for novel translational modulators, and identified numerous preclinical and clinical therapeutic compounds, with diverse nominal targets, that preferentially suppress translation of ribosomal proteins. Surprisingly, some of these compounds act in a manner that bypasses canonical regulation by mTOR-4EBP1/2. Instead, these compounds exert their translational effects in a manner that is dependent upon GCN2-eIF2α, a central signaling axis within the integrated stress response. Furthermore, we were also able to identify metabolic perturbations that also suppress ribosomal protein translation in an mTOR-independent manner. Together, we describe a novel translational assay that is directly applicable to large-scale RNA translation studies, and that enabled us to identify a non-canonical, mTOR-independent mode for translational regulation of ribosomal proteins.
2018-09-21 | GSE118422 | GEO
Project description:Mammalian target of rapamycin (mTOR) is implicated in synaptic plasticity and local translation in dendrites. Here we found that the mTOR inhibitor, rapamycin, increased the Kv1.1 voltage-gated potassium channel protein in hippocampal neurons and promoted Kv1.1 surface expression on dendrites without altering its axonal expression. Moreover, endogenous Kv1.1 mRNA was detected in dendrites. Using Kv1.1 fused to the photo-convertible fluorescence protein Kaede as a reporter for local synthesis, we observed Kv1.1 synthesis in dendrites upon inhibition of mTOR or the N-methyl-D-aspartate (NMDA) glutamate receptor. Thus, synaptic excitation may cause local suppression of dendritic Kv1 channels by reducing their local synthesis. Keywords: comparison of synaptosomal mRNA to total hippocampal mRNA
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Project description:Forkhead Box O (FOXO) transcription factors are versatile players in diverse cellular processes, affecting tumorigenesis, metabolism, stem cell maintenance and lifespan. To understand the transcriptional output of FOXO3 activation, we investigate features that define the subset of enhancer binding events that actually contribute to gene regulation. We show FOXO3 transcriptional output is determined by the amount of bound FOXO3, which in turn is determined by motif presence, pre-existing enhancer activity and accessibility. In this manner, FOXO3 amplifies pre-existing levels of activity marks and potentiates enhancer RNA transcription. We conclude that not only enhancer presence and sequence content, but also the pre-existing activity dictates FOXO3 binding and transcriptional output. Considering the flexible and cell type specific nature of regulatory regions and their activity, our observations provide a novel explanation for the diversity in FOXO transcriptional programs and introduce chromatin context as a new player in the regulation of FOXO activity in ageing and disease. Examination of histone modifications and transcriptome changes upon FOXO activation
2013-11-26 | E-GEOD-50243 | biostudies-arrayexpress
Project description:Genomes pervasively produce long non-coding RNAs (lncRNAs) of largely unknown functions. Some of these lncRNAs have been implicated in roles related to ageing and associated diseases. Here we characterize aal1 (ageing-associated lncRNA 1) which is induced in non-dividing, ageing cells of fission yeast. Deletion of aal1 shortens the chronological lifespan of non-dividing cells, while ectopic overexpression of aal1 from a plasmid prolongs their lifespan, indicating that this lncRNA acts in trans. We find that aal1 genetically interacts with coding genes functioning in processes related to protein translation, and aal1 overexpression leads to repression of ribosomal protein genes and inhibition of cell growth. The aal1 RNA localizes to the cytoplasm and associates with ribosomes. Notably, aal1 deletion or overexpression is sufficient to increase or decrease the cellular ribosome content, respectively. We identify the mRNA rpl1901, encoding a ribosomal protein, as a binding target of aal1. The expression of rpl1901 is moderately repressed by aal1, and such moderate repression is critical and sufficient to extend the chronological lifespan. Remarkably, expression of the yeast aal1 lncRNA in the fly gut triggers a significant extension of the lifespan in flies. Based on these findings, we propose that the aal1 RNA can reduce the ribosome content by decreasing the levels of the Rpl1901 ribosomal protein, thus attenuating protein translation and promoting longevity. Although the aal1 lncRNA itself is not conserved, its effects in the fly raise the possibility that other organisms feature related mechanisms involving conserved ribosome-associated processes to control ageing.
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