Astrocyte-Derived Estrogen Regulates Reactive Astrogliosis and is Neuroprotective Following Ischemic Brain Injury
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PROVIDER: PRJNA646082 | ENA |
REPOSITORIES: ENA
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Project description:We examined the transcriptional changes modulated in ischemic brain of astrocyte specific aromatase knockout mice (GFAP-ARO-KO) by performing global transcriptome analysis.Total RNA was isolated from FLOX and GFAP-ARO-KO mice that underwent 20-minute CCA occlusion, followed by 24-hour reperfusion. The collected hippocampi samples were subjected to RNA isolation and Illumina TruSeq RNA sample preparation and sequencing was done using UT Health San Antonio genomics core facility protocol. We observed that that the ischemic GFAP-ARO-KO mouse hippocampus failed to upregulate a group of genes, which have been suggested to represent the “A2” neuroprotective signature of astrocytes. In addition, the JAK-STAT3 pathway, which is critical for the induction of reactive astrogliosis, was significantly down-regulated in the GFAP-ARO-KO hippocampus following GCI. Additional pathways that altered in GFAP-ARO-KO hippocampus were related to cytokine, chemokine and inflammatory signaling pathways.
2023-07-13 | GSE154383 | 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: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:Reactive astrogliosis is characterized by a profound change in astrocyte phenotype in response to all CNS injuries and diseases. To better understand the reactive astrocyte state, we used Affymetrix GeneChip arrays to profile gene expression in populations of reactive astrocytes isolated at various time points after induction using two different mouse injury models, ischemic stroke and neuroinflammation. Young adult male mice underwent middle cerebral artery occlusion (MCAO) to produce ischemic stroke or control sham surgery. Young adult mice were injected intraperitoneally with 5 mg/kg lipopolysaccharide (LPS) to produce neuroinflammation or saline for control. Astrocytes were acutely purified from control and injured brains at 1 day after injury for LPS/saline injection and 1, 3 days and 7 days after MCAO/sham surgeries.
2012-05-01 | E-GEOD-35338 | biostudies-arrayexpress
Project description:Reactive astrogliosis is characterized by a profound change in astrocyte phenotype in response to all CNS injuries and diseases. To better understand the reactive astrocyte state, we used Affymetrix GeneChip arrays to profile gene expression in populations of reactive astrocytes isolated at various time points after induction using two different mouse injury models, ischemic stroke and neuroinflammation.
2012-05-02 | GSE35338 | GEO
Project description:Expression of the 17β-estradiol (E2) synthesis enzyme aromatase is highly upregulated in astrocytes following brain injury. However, the precise role of astrocyte-derived E2 in the injured brain remains unclear. In the current study, we generated a glial fibrillary acidic protein (GFAP) promoter-driven aromatase knock-out (GFAP-ARO-KO) mouse model to deplete astrocyte-derived E2 in the brain and determine its roles after global cerebral ischemia (GCI) in male and female mice. GFAP-ARO-KO mice were viable and fertile, with normal gross brain structure, normal morphology, intensity and distribution of astrocytes, normal aromatase expression in neurons, and normal cognitive function basally. In contrast, after GCI, GFAP-ARO-KO mice: (1) lacked the normal elevation of astrocyte aromatase and hippocampal E2 levels; (2) had significantly attenuated reactive astrogliosis; and (3) displayed enhanced neuronal damage, microglia activation, and cognitive deficits. RNA-sequencing (RNA-seq) analysis revealed that the ischemic GFAP-ARO-KO mouse hippocampus failed to upregulate the "A2" panel of reactive astrocyte genes. In addition, the JAK-STAT3 pathway, which is critical for the induction of reactive astrogliosis, was significantly downregulated in the GFAP-ARO-KO hippocampus following GCI. Finally, exogenous E2 administration fully rescued the compromised JAK-STAT3 pathway and reactive astrogliosis, and reversed the enhanced neuronal damage and microglial activation in the GFAP-ARO-KO mice after GCI, suggesting that the defects in the KO mice are because of a loss of E2 rather than an increase in precursor androgens. In conclusion, the current study provides novel genetic evidence for a beneficial role of astrocyte-derived E2 in reactive astrogliosis, microglial activation, and neuroprotection following an ischemic injury to the brain.SIGNIFICANCE STATEMENT Following cerebral ischemia, reactive astrocytes express the enzyme aromatase and produce 17β-estradiol (E2), although the precise role of astrocyte-derived E2 is poorly understood. In this study, we generated a glial fibrillary acidic protein (GFAP) promoter-driven aromatase knock-out (GFAP-ARO-KO) mouse to deplete astrocyte-derived E2 and elucidate its roles after global cerebral ischemia (GCI). The GFAP-ARO-KO mice exhibited significantly attenuated reactive astrogliosis, as well as enhanced microglial activation, neuronal damage, and cognitive dysfunction after GCI. Transcriptome analysis further revealed that astrocyte-derived E2 was critical for the induction of the JAK-STAT3 signaling pathway, as well as the A2 reactive astrocyte phenotype after ischemia. Collectively, these findings indicate that astrocyte-derived E2 has a key role in the regulation of reactive astrogliosis, microglial activation, and neuroprotection after cerebral ischemia.
| S-EPMC7726540 | biostudies-literature
Project description:Astrogliosis is a hallmark of the response to brain ischemia, comprised of changes in gene expression and morphology. Hsp72 protects from cerebral ischemia, and although several mechanisms of protection have been investigated, effects on astrocyte activation are unknown. To identify potential mechanisms of protection, gene expression was assessed in mice subjected to middle cerebral artery (MCAO) or sham surgery, of either wildtype (WT) or Hsp72-overexpressing (Hsp72Tg) mice. After stroke, both genotypes exhibited genes related to cell death, stress response, and immune response. Furthermore, genes indicative of astrocyte activation, including cytoskeletal proteins and cytokines, were upregulated. To measure astrocyte activation after stroke, detailed histological and morphological analyses were performed in the cortical penumbra after stroke using unbiased stereology. Consistent with other reports, we observed a marked and persistent increase in glial fibrillary acidic protein (GFAP ) as soon as 3 hours after MCAO. In contrast, vimentin immunoreactivity appeared 12-24 hours after stroke, peaked at 72 hours, and returned to baseline after 30 days. Surprisingly, no change in overall astrocyte number was observed based on glutamine synthetase (GS) immunoreactivity. To determine if Hsp72Tg mice exhibited altered astrocyte activation compared to WT controls, morphological evaluation by fractal analysis was used. Overexpression of Hsp72 reduced astrocyte cell area, arbor area, and to a lesser extent fractal dimension, 72 hours following stroke. In conclusion, in vivo overexpression of Hsp72 alters gene expression following stroke, including genes involved in astrocyte activation, and decreases astrocyte activation acutely following MCAO. Thus, modulation of astrogliosis may be a neuroprotective mechanism exerted by Hsp72 after ischemia. A total of 10 samples were analyzed, with 5 of each genotype, wildtype (WT) and Hsp72-overexpressing (Hsp72Tg) mice. Of the 5 in each group, 3 received middle cerebral artery occlusion (MCAO) and 2 received a sham surgery. The sham samples serve as the controls for the MCAO samples in each genotype. All samples were taken from the ischemic or control hemisphere 24 hours after surgery.
2013-01-11 | E-GEOD-28731 | biostudies-arrayexpress
Project description:A Molecular Switch for Neuroprotective Astrocyte Reactivity
| PRJNA996144 | ENA
Project description:A Molecular Switch for Neuroprotective Astrocyte Reactivity
| PRJNA1030019 | ENA
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