Mus musculus
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ABSTRACT:
PROVIDER: PRJNA281992 | ENA |
REPOSITORIES: ENA
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Project description:Injury to the adult brain induces activation of resident astrocytes, which serves as a compensatory response modulating tissue damage and recovery. However, the mechanism governing astrocyte activation and the role of reactive astrocytes remain largely unknown. Here we show that SOX2, a transcription factor critical for stem cells and brain development, is also required for injury-induced activation of adult cortical astrocytes. Genome-wide ChIP-seq analysis reveals that SOX2 binds to regulatory regions of genes associated with signaling pathways controlling reactive gliosis, such as Socs3, Nr2e1, Notch1, and Akt2. Inducible deletion of Sox2 in adult astrocytes greatly diminishes their response to traumatic injury and, most unexpectedly, restricts injury-induced cortical loss. Together, these results uncover an essential role of SOX2 in terminally differentiated cells and implicate that SOX2-dependent reactive astrocytes may be targeted for regeneration after traumatic brain injury.
2018-02-22 | GSE85213 | GEO
Project description:The intrinsic mechanisms that regulate neurotoxic versus neuroprotective astrocyte phenotypes and their effects on central nervous system (CNS) degeneration and repair remain poorly understood. Here, we show injured white matter astrocytes differentiate into two distinct C3-positive and C3-negative reactive populations, previously simplified as neurotoxic (A1) and neuroprotective (A2)1,2, which can be further subdivided into unique subpopulations defined by proliferation and differential gene expression signatures. We find the balance of neurotoxic versus neuroprotective astrocytes is regulated by discrete pools of compartmented cAMP derived from soluble adenylyl cyclase (sAC) and show proliferating neuroprotective astrocytes inhibit microglial activation and downstream neurotoxic astrocyte differentiation to promote retinal ganglion cell (RGC) survival. Finally, we report a new, therapeutically tractable viral vector to specifically target optic nerve head astrocytes and show elevating nuclear or depleting cytoplasmic cAMP in reactive astrocytes inhibits deleterious immune cell infiltration and promotes RGC survival after optic nerve injury. Thus, soluble adenylyl cyclase and compartmented, nuclear- and cytoplasmic-localized cAMP in reactive astrocytes act as a molecular switch for neuroprotective astrocyte reactivity that can be targeted to inhibit microglial activation and neurotoxic astrocyte differentiation to therapeutic effect. These data expand upon and define new reactive astrocyte subtypes and represents a novel step towards the development of gliotherapeutics for the treatment of glaucoma and other optic neuropathies.
2023-12-11 | GSE245816 | GEO
Project description:Astrocytes differentiate into a spectrum of neurotoxic and neuroprotective reactive subpopulations after CNS injury and in disease. In astrocyte conditional ADCY10 (sAC) knockout mice, reactive astrocytes exhibit a shift towards neurotoxic phenotypes implicating sAC as a critical regulator of neuroprotective astrocyte differentiation.
2023-12-11 | GSE237675 | GEO
Project description:Despite accumulating evidence of functional interactions between astrocytes and microglia in central nervous system (CNS) injury and disease, mechanisms coordinating their response to CNS insults remain incompletely understood. We report that injury-reactive astrocytes at the lesion border upregulate colony stimulating factor 1 (CSF1) required for microglial proliferation, wound closure, and motor recovery after focal spinal cord injury. Intriguingly, astrocyte-targeted deletion of CSF1 also reduces cell number of border-forming astrocytes, revealing positive feedback regulation between astrocytes and microglia. We further show that microglia produce interferon ? (IFN?), which reciprocally supports astrocyte survival. Genetic disruption of interferon signaling in astrocytes in turn impairs astrocytic border formation, coordination with microglia in wound healing, and motor recovery. This work uncovers astrocyte-microglia crosstalk via CSF1 and IFN? that synergizes the acute injury response of these cells for neural repair, providing insights into fundamental biology of astrocyte-microglia communication and its therapeutic potential.
2026-04-28 | GSE326801 | GEO
Project description:Transcriptome profiling of mice overexpressing a constitutively active form of CREB in astrocytes (VP16-CREB) vs WT mice, both in normal conditions and after a focal cryolesion (C) in the parietal cortex. Goal is to determine which astrocytic genes are responsible for the neuroprotection we observed in VP16-CREB mice after injury.
2016-04-27 | GSE68187 | GEO
Project description:Astrocytes adapt to injury and disease by entering reactive states with altered gene expression, morphology, and function, but we still do not know how these states evolve over time in human cells or whether they acquire immune effector properties. Using human cortical organoids (hCOs) and primary fetal cortical tissue, we mapped the temporal dynamics and plasticity of inflammatory human astrocytes. Brief and prolonged exposure to inflammatory cytokines elicited robust, time-dependent changes in astrocyte transcriptomes and chromatin accessibility, and these exposures produced distinct acute and chronic reactive signatures. Despite these widespread genomic alterations, astrocytes that experienced either acute or chronic cytokine exposure reverted to a quiescent gene expression and chromatin state within days of cytokine withdrawal, which demonstrates a high degree of plasticity. Chronic inflammatory settings, but not acute ones, revealed a second layer of reactivity in which astrocytes induced major histocompatibility complex class II (MHCII) genes and surface MHCII protein. We validated MHCII expression and surface localization in primary human fetal astrocytes, in organotypic fetal cortical slices that include microglia, and in human brain tissue from patients with chronic inflammatory lesions. We propose that delayed MHCII emergence reflects progressive activation of interferon linked signaling in astrocytes, including low level interferon gamma production. Through co-immunoprecipitation and mass spectrometry of MHCII complexes from TIC-treated fetal astrocytes we identified candidate MHCII-presented peptides and confirmed that astrocytes can process and display exogenous peptides derived from human fetal neurons.
2026-04-15 | GSE313768 | GEO
Project description:Traumatic brain injury (TBI) initiates a cascade of cellular and molecular events that promote acute and long-term patterns of neuronal, glial, vascular, and synaptic vulnerability leading to lasting neurological deficits. These complex responses lead to patterns of programmed cell death, diffuse axonal injury, increased blood-brain barrier disruption, neuroinflammation, and reactive gliosis, each a potential target for therapeutic interventions. Posttraumatic therapeutic hypothermia (TH) has been reported to be highly protective after brain and spinal cord injury and studies have investigated molecular mechanisms underlying mild hypothermic protection while commonly assessing heterogenous cell populations. In this study we conducted single-cell RNA sequencing (scRNAseq) on cerebral cortical tissues after experimental TBI followed by a period of normothermia or hypothermia to clarify multiple cell type-specific transcriptional responses. C57BL/6 mice underwent moderate controlled cortical impact (CCI) injury or sham surgery and then placed under sustained normothermia (37⁰C) or hypothermia (33⁰C) for 2 hrs. After 24 hours, cortical tissues including peri-contused regions were processed for scRNAseq. Unbiased clustering and differential expression tests revealed cellular heterogeneity, reactive astrocytes, microglia, and leukocyte infiltration at this subacute posttraumatic time point. The analysis also revealed vascular and immune subtypes associated with neovascularization and debris clearance, respectively. Compared to normothermic conditions, TH treatment altered the abundance of specific cell subtypes and induced reactive astrocyte-specific modulation of neurotropic factor gene expression. In addition, an increase in the proportion of endothelial tip cells in the hypothermic TBI group was documented compared to normothermia. These data emphasize the importance of early temperature-sensitive glial and vascular cell processes in producing potentially neuroprotective downstream signaling cascades in a cell-type-dependent manner. The use of single cell sequencing to address cell-specific mechanisms underlying therapeutic treatments provides a valuable resource for identifying targetable biological pathways for the development of neuroprotective and reparative interventions.
2025-04-21 | GSE290150 | GEO
Project description:Central nervous system (CNS) lesions become surrounded by neuroprotective borders of newly proliferated reactive astrocytes. Fundamental features of these cells are poorly understood. Here, using temporal transcriptome analysis of Aldh1l1-expressing local astrocytes we showed that after CNS injury, local mature astrocytes dedifferentiated, proliferated, and become transcriptionally reprogrammed to permanently altered new functional states, with persisting downregulation of molecules associated with astrocyte-neuron interactions, and upregulation of molecules associated with wound healing, microbial defence, and interactions with stromal and immune cells. Our findings show that at CNS injury sites, local mature astrocytes proliferate and adopt canonical features of essential wound repair cells that persist in adaptive states and are the predominant source of neuroprotective borders that re-establish CNS integrity by separating neural parenchyma from stromal and immune cells as occurs throughout the healthy CNS.
2023-08-28 | GSE241628 | GEO
Project description:Astrocytes are abundant glial cells in the central nervous system (CNS) that play important roles in cerebral ischemia-reperfusion injury. Following brain ischemia, astrocytes can trigger endogenous neuroprotective mechanisms such as neurogenesis, regulation of inflammation, transfer of mitochondria, and defense against oxidative stress. Transforming growth factor beta 1 (TGF-β1) is known as an injury-related cytokine, particularly associated with neurogenesis, neuronal migration, inflammatory reactions, and astrocyte scar formation in response to brain injury. TGF-β1 is closely related to ischemia-reperfusion brain injury and plays a significant role as both effectors and targets of I/R brain injury. Upregulation of endogenous TGF-β1 in neurons may contribute to preventing apoptosis after ischemic insult. TGF-β1 exerts dynamic effects in tissues through autocrine and paracrine signaling pathways as a secretory factor. The current study suggests that the multiple functions exerted by astrocytes might potentially be mediated by TGF-β1 signaling, raising the idea that astrocytes could be a potential therapeutic target for neuroprotection as sources or targets of TGF-β1. However, few studies are currently available on the effects of TGF-β1 on astrocytes after ischemia-reperfusion brain injury. Although current research shows that transforming growth factor-beta acts as a neuroprotective agent in cerebral ischemia, its specific mechanism is still not completely clear. In this study, RNA sequencing analysis was performed to investigate the potential mechanism of astrocytes pretreated with TGF-β1. Our study found that TGF-β1 mediates the upregulation of DUSP4 in astrocytes, which plays a neuroprotective role after ischemia-reperfusion injury. Overexpression of TGF-β1 inhibits the activation of astrocytes, accompanied by decreased levels of inflammatory factors and reactive oxygen species (ROS), while promoting the transfer of mitochondria between astrocytes and neurons. This enhanced neuron survival and axonal regeneration after injury. Hence, this study provides further insights into strategies for inhibiting neurological impairment and suggests a potential therapeutic target after ischemia-reperfusion injury.
2025-01-08 | GSE253273 | GEO
Project description:Following contusive spinal injury astrocytes undergo inflammatory activation and proliferation in a process known as astrogliosis. Reactive astrocytes are attractive therapeutic targets as they sit central to many of the immune recruitment, injury response, and tissue healing processes of the spinal cord. However, methods of targeted expression of exogenous therapeutic genes within astrocytes must be validated to not alter the normal immunological involvement of astrocytes. To investigate the effect of transgene expression within astrocytes upon the immunological state of the contused cord, we injected the astrocyte-selective AAV5-GfaABC1D-dYFP reporter vector into an animal model of moderate contusive spinal cord injury. Bulk RNA microarrays were used to assess transcriptomic changes of the perilesional tissue.
2021-08-26 | GSE182796 | GEO