Notch Signaling Reprograms Glial Lipid Metabolism to Promote Hypoxia Resistance
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ABSTRACT:
ORGANISM(S): Drosophila melanogaster
PROVIDER: GSE334949 | GEO | 2026/06/26
REPOSITORIES: GEO
Similar Datasets
Project description: Not available
| S-EPMC8044706 | biostudies-literature
Project description:Background Temporal lobe epilepsy (TLE) is the most common form of focal epilepsy and is characterized by a pathological cascade of excitotoxicity that leads to neuroinflammation, progressive neuronal loss, and subsequent cognitive decline. Despite its prevalence, effective disease-modifying therapies remain lacking. Previous studies have demonstrated that the endocannabinoid system contributes to epileptic activity. In particular, inactivation of monoacylglycerol lipase (MAGL), the key rate-limiting enzyme responsible for the degradation of the endocannabinoid 2-arachidonoylglycerol (2-AG), an endogenous lipid mediator with anti-inflammatory and neuroprotective properties, suppresses seizures and reduces neuroinflammation. However, the cellular and molecular mechanisms underlying these protective effects remain unclear. Methods To dissect the cellular mechanisms underlying MAGL-mediated neuroprotection, we employed a kainic acid (KA)-induced status epilepticus model in mice with global, astrocyte-specific (aKO), and neuron-specific (nKO) deletion of mgll. We combined single-nucleus RNA sequencing (snRNA-seq) to map the transcriptomic landscape of glial responses with pharmacological interventions to validate key signaling pathways, as well as behavioral assays to assess functional recovery. Results We demonstrated that astrocyte-specific, but not neuron-specific, mgll deletion was sufficient to attenuate seizure susceptibility and hippocampal neurodegeneration, thereby recapitulating the protective phenotype observed in global knockouts. Transcriptomic profiling revealed that astrocytic MAGL deficiency fundamentally reshaped the glial response to injury by preventing the transition to pro-inflammatory reactive astrocyte states and suppressing the activation of disease-associated microglia (DAM). Mechanistically, we identified a signaling pathway in which the neuroprotective effects of MAGL inhibition depend on cannabinoid receptor 1 (CB1) activation and are mediated by downstream peroxisome proliferator-activated receptor γ (PPAR-γ) signaling. Either genetic deletion of CB1 or pharmacological blockade of PPAR-γ abolished the protective effects. Furthermore, aKO mice exhibited reduced neuronal loss, preserved synaptic structural integrity and protection against post-seizure cognitive deficits. Conclusion These findings reveal astrocytic MAGL as a crucial regulatory node in the epileptic brain and demonstrated that enhancing 2-AG signaling in astrocytes orchestrates neuroprotection via CB1-PPAR-γ signaling pathways, thereby reducing neuroinflammation, preserving synaptic function, and preventing the cognitive comorbidities associated with epilepsy.
2026-02-18 | GSE318570 | GEO
Project description:Hypoxia tolerance is mainly controlled by the hypoxia signaling pathway and HIF-1α/2α serve as master regulators in this pathway. Here we identify MYLIP, an E3 ubiquitin ligase thought to specifically target lipoprotein receptors, as a negative regulator of HIF-1α/2α. MYLIP interacts with HIF-1α/2α and catalyzes K27-linked polyubiquitination at lysine 118/442 (HIF-1α) or lysine 117 (HIF-2α). This modification induces proteasomal degradation of HIF-1α, resulting in inhibition of hypoxia signaling. Furthermore, Mylip-deficient bluntsnout bream, zebrafish and mice are more tolerant to hypoxia. These findings reveal a role for MYLIP in regulating hypoxia signaling and identify a target for developing fish strains with high hypoxia tolerance for the benefit of the
2024-12-04 | GSE283363 | GEO
Project description:Hypoxia (low oxygen) and Notch signaling are two important regulators of vascular development, but how they interact in controlling the choice between arterial and venous fates for endothelial cells during vasculogenesis is less well understood. In this report, we show that hypoxia and Notch signaling intersect in promotion of arterial differentiation. Hypoxia upregulated expression of the Notch ligand Dll4 and increases Notch signaling, in a process requiring the vasoactive hormone adrenomedullin but not endogenous VEGF. Notch signaling also upregulated Dll4 expression, leading to a positive feedback loop sustaining Dll4 expression and Notch signaling. In addition, functional Notch signaling was required for hypoxia to upregulate the arterial marker genes Depp, connexin40 (Gja5), Cxcr4 and Hey1. In conclusion, the data reveal an intricate interaction between hypoxia and Notch signaling in the control of endothelial cell differentiation, including a hypoxia/adrenomedullin/Dll4 axis that initiates Notch signaling and a requirement for Notch signaling to effectuate hypoxiamediated induction of the arterial differentiation program.
2013-02-08 | GSE35894 | GEO
Project description:Hypoxia (low oxygen) and Notch signaling are two important regulators of vascular development, but how they interact in controlling the choice between arterial and venous fates for endothelial cells during vasculogenesis is less well understood. In this report, we show that hypoxia and Notch signaling intersect in promotion of arterial differentiation. Hypoxia upregulated expression of the Notch ligand Dll4 and increases Notch signaling, in a process requiring the vasoactive hormone adrenomedullin but not endogenous VEGF. Notch signaling also upregulated Dll4 expression, leading to a positive feedback loop sustaining Dll4 expression and Notch signaling. In addition, functional Notch signaling was required for hypoxia to upregulate the arterial marker genes Depp, connexin40 (Gja5), Cxcr4 and Hey1. In conclusion, the data reveal an intricate interaction between hypoxia and Notch signaling in the control of endothelial cell differentiation, including a hypoxia/adrenomedullin/Dll4 axis that initiates Notch signaling and a requirement for Notch signaling to effectuate hypoxiamediated induction of the arterial differentiation program. 12 microarray samples consisting of >50,000 FACS sorted CD31+ cells purified from wild type mouse CCE ES cells that were differentiated into the endothelial lineages in 3 biological replicates. The ES cells were subjected to embryoid body formation over 4 days in hanging drop cultures, FACS sorted for Flk1 positive vascular progenitors cells and plated for a further 4 days in normoxia (21% oxygen) or hypoxia (1.5-2% oxygen) with or without 4 umol/l gamma-secretase inhibitor L-685.458.
2013-02-08 | E-GEOD-35894 | biostudies-arrayexpress
Project description:Background: Interaction between key signaling mechanisms is important to generate the diversity in signaling output required for proper control of cellular differentiation and function, although the molecular manifestations of such cross-talk are only partially understood. Notch signaling and the cellular response to hypoxia intersect at different points in the signaling cascades, and in this report we analyze the consequences of this cross-talk at the transcriptome level. Results: Mouse ES cells were subjected to various combinations of hypoxia and/or activated Notch signaling, and the transcriptome changes could be grouped into different categories, reflecting various modes of hypoxia and Notch signaling integration. Two principal categories of novel Notch- and hypoxia-induced genes were identified: i) a larger set of genes induced by one pathway and not significantly affected by the activity status of the other pathway; and ii) a smaller set of genes co-regulated by Notch and hypoxia. In the latter category, we identified genes that were induced by hypoxia and the expression of which was enhanced by active Notch signaling. In addition, a number of genes were induced by Notch and hypoxia independently, and a final category of genes required simultaneous activation of Notch and hypoxia to be significantly induced. Several of the hypoxia- and Notch-induced genes were found to be upregulated in various forms of cancer. Conclusions: We identify novel Notch and hypoxia downstream genes and genes co-regulated by the two pathways, providing a molecular platform to better understand the intersection between the two signaling cascades in normal development and cancer.
2009-12-31 | GSE19074 | GEO
Project description: Not available
| S-EPMC5829509 | biostudies-literature
Project description:Within the adult mammalian dentate gyrus (DG) of the hippocampus, glutamate stimulates neural stem cell (NSC) self-renewing proliferation, providing a link between adult neurogenesis and local circuit activity. Here, we show that glutamate-induced self-renewal of adult DG NSCs requires glutamate transport via excitatory amino acid transporter 1 (EAAT1) to stimulate lipogenesis. Loss of EAAT1 prevented glutamate-induced self-renewing proliferation of NSCs in vitro and in vivo, with little role evident for canonical glutamate receptors. Transcriptomics and further pathway manipulation revealed that glutamate simulation of NSCs relied on EAAT1 transport-stimulated lipogenesis, likely secondary to intracellular Ca2+ release and glutamate metabolism. Our findings demonstrate a critical, direct role for EAAT1 in stimulating NSCs to support neurogenesis in adulthood, thereby providing insights into a non-canonical mechanism by which NSCs sense and respond their niche.
2023-06-14 | GSE217059 | GEO
Project description:The Notch signaling pathway regulates several differentiation and developmental processes. Reduction of oxygen availability, a condition referred to as hypoxia, impacts on the Notch response. Here we made use of RNA-Seq and ChIP-Seq analysis to investigate the Notch/hypoxia crosstalk at genomic level.
2022-07-07 | GSE194003 | GEO
Project description:Hypoxia-induced cell injury has been related to multiple pathological conditions. In order to render hypoxia-sensitive cells and tissues resistant to low O2 environment, in this current study, we used Drosophila melanogaster as a model to dissect the mechanisms underlying hypoxia-tolerance. A D. melanogaster strain that lives perpetually in an extremely low-oxygen environment (4% O2, an oxygen level that is equivalent to that over about 4,000 m above Mt. Everest) was generated through laboratory selection pressure using a continuing reduction of O2 over many generations. This phenotype is genetically stable since selected flies, after several generations in room air, survive at this low O2 level. Gene expression profiling showed striking differences between tolerant and naïve flies, in larvae and adults, both quantitatively and qualitatively. Up-regulated genes in the tolerant flies included signal transduction pathways (e.g., Notch and Toll/Imd pathways), but metabolic genes were remarkably down-regulated in the larvae. Furthermore, a different allelic frequency and enzymatic activity of the triose phosphate isomerase (TPI) was present in the tolerant versus naïve flies. The transcriptional suppressor, hairy, was up-regulated in the microarrays and its binding elements were present in the regulatory region of the specifically down-regulated metabolic genes but not others, and mutations in hairy significantly reduced hypoxia tolerance. We conclude that, the hypoxia-selected flies: (a) altered their gene expression and genetic code, and (b) coordinated their metabolic suppression, especially during development, with hairy acting as a metabolic switch, thus playing a crucial role in hypoxia-tolerance. Keywords: genetic bases of hypoxia adaptation 27 isogenic D. melanogaster Lines were pooled and following long-term selection over generations with decreased oxygen level in the culture environment. The differences in gene expression were compared between adapted flies and generation matched naive controls by microarray. Pooled RNA samples from 3rd instar larvae of 27 parental lines were used as common reference.
2010-06-25 | E-GEOD-8803 | biostudies-arrayexpress