Astroglial Hmgb1 regulates postnatal astrocyte morphogenesis and cerebrovascular maturation
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE236429 | GEO | 2023/07/10
REPOSITORIES: GEO
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Project description:Astrocytes are intimately linked with brain vessels, a relationship that is critical for neuronal health and function. However, key astroglial molecular factors that drive these physical and functional associations during postnatal brain development have not yet been identified. We characterized structural and transcriptional changes in mouse cortical astrocytes and microvessels during the first two postnatal weeks and found that high-mobility group box 1 (Hmgb1), normally upregulated with injury and involved in adult cerebrovascular repair, was highly expressed in astrocytes at birth to then decreased rapidly. Astrocyte-selective ablation of Hmgb1 in newborn mice affected astrocyte morphology and endfoot placement, induced disruption of endfoot proteins connexin43 and aquaporin-4, induced transcriptional changes in astrocytes, and profoundly altered endothelial cell ultrastructure. While lack of astroglial Hmgb1 did not affect the blood-brain barrier or angiogenesis postnatally, it impaired neurovascular coupling and behavior in adult mice. These findings identify astroglial Hmgb1 as a key player in postnatal gliovascular maturation.
2023-06-13 | GSE224784 | GEO
Project description:LC/MS/MS analysis was performed on astroglial exosome samples (3 biological replicates) to identify proteins expressed on the surface of astroglial exosomes. Thes astroglial exosome samples were purified using size-exclusion column from astrocyte conditioned medium (ACM) of primary astrocyte cultures.
2023-08-10 | PXD040650 | Pride
Project description:We aimed to identify astroglial transcripts preferentially translated in the neurovascular unit. The translatome of whole astrocytes extracted following the bacTRAP protocol was compared to a translatome of astrocyte perivascular endfeet.
2017-01-27 | GSE72937 | GEO
Project description:Astrocytes, the most prominent glial cell type in the brain, send specialized processes called endfeet around blood vessels and express a large molecular repertoire regulating the cerebrovascular system physiology. One of the most striking properties of astrocyte endfeet is their enrichment in gap junction protein Connexin 43 and 30 (Cx43 and Cx30) allowing in particular for direct intercellular trafficking of ions and small signaling molecules through perivascular astroglial networks. In this study, we addressed the specific role of Cx30 at the gliovascular interface. Using an inactivation mouse model for Cx30 (Cx30M-NM-^T/M-NM-^T), we showed that absence of Cx30 does not affect blood-brain barrier (BBB) organization and permeability. However, it results in the cerebrovascular fraction, in a strong upregulation of Sgcg encoding g-Sarcoglycan (SG), a member of the Dystrophin-associated protein complex (DAPC) connecting cytoskeleton and the extracellular matrix. The same molecular event occurs in Cx30T5M/T5M mutated mice, where Cx30 channels are closed, demonstrating that Sgcg regulation relied on Cx30 channel functions. We further characterized the cerebrovascular Sarcoglycan complex (SGC) and showed the presence of M-NM-1-, M-NM-2-, M-NM-4-, M-NM-3-, M-NM-5- and M-NM-6- SG, as well as Sarcospan. Altogether, our results suggest that the Sarcoglycan complex is present in the cerebrovascular system, and that expression of one of its members, g-Sarcoglycan, depends on Cx30 channels. As described in skeletal muscles, the SGC may contribute to membrane stabilization and signal transduction in the cerebrovascular system, which may therefore be regulated by Cx30 channel-mediated functions. Comparison of 3-month-old Cx30 deleted mice against WT genetic background.
2015-03-03 | E-GEOD-59148 | biostudies-arrayexpress
Project description:Astroglial cells in the adult brain constitute a heterogeneous population endowed with region-specific properties. Recently, they have acquired greater relevance as active components of the adult neural stem cell (aNSC) niches. Astrocytes located in the vicinity of aNSC reservoirs are thought to regulate aNSC behaviour. We have compared the function of glial cells isolated from the postnatal and adult subventricular zone and hippocampus (two stem cell niches, where aNSCs self-renew and give rise to immature neurons), from the olfactory bulb (a neurogenic region where the immature neurons cease to proliferate and terminally differentiate) and from a non-stem and non-neurogenic area such as the ventral mesencephalon. Co-culture experiments demonstrate that subventricular zone glial cells secrete soluble signals that promote NSC self-renewing divisions. We used microarrays to detail the global gene expression of astroglial cells isolated from four different brain regions (olfactory bulb, ventral mesencephalon, hippocampus and subventricular zone) and identified up-regulated genes coding for secreted proteins in astrocytes from the subventricular zone. Primary astrocytes were cultured from four CD-1 mouse brain regions and cells were employed for RNA extraction and hybridization on Affymetrix microarrays. Primary tissue for the astrocyte cultures was dissected from four postnatal day 3 littermate pups. The tissue from the three pups was pooled in order to reduce individual differences of expression profiles.
2012-05-31 | E-GEOD-36456 | biostudies-arrayexpress
Project description:Astroglia, the star-shaped cells found throughout the central nervous system are the most numerous cell type in the brain. The astroglial response to injury, generically termed reactive astrogliosis, is classically defined by cellular hypertrophy and process extension, increased glial filament production, and some degree of proliferation. Astrogliosis and its functional outcomes, glial scar formation and neuroinflammation, are often viewed as detrimental to recovery. However, increasing evidence points to neuroprotective roles of reactive astroglia in the setting of brain injury. Therapeutic modulation of this double-edged sword will require detailed knowledge of mechanisms by which specific signals induce detrimental and beneficial phenotypes. This proposal is is a logical extension of a published, peer reviewed study (Heffron DS and Mandell JW, Opposing roles of ERK and p38 MAP kinases in FGF2-induced astroglial process extension. Mol Cell Neurosci 2005, 28:779-90). The downstream gene expression changes underlying these pathway-specific responses are largely unknown. The data generated from the proposed project will delineate pathway-specific gene expression responses of astroglia to fibroblast growth factors. This information will allow a rational approach to pharmacological approaches to modulate reactive astrogliosis in brain and spinal cord injury. Determine the astroglial gene expression program elicited by fibroblast growth factor-2, and dissect specific contributions of the ERK and p38 MAP kinase pathways using highly specific pharmacological inhibitors. FGF2, acting via two distinct intracellular signaling pathways, ERK- and p38 MAPK, leads to pathway-specific gene expression changes in astrocytes which promote the morphological plasticity (ERK-dependent) and pro-inflammatory properties (p38-dependent) of reactive astroglia. Cell culture; Neonatal primary astrocyte cultures are prepared exactly as previously described (Heffron and Mandell, 2005), using slight modifications of established protocols (McCarthy and de Vellis, 1980). Astrocytes prepared with these methods comprised greater than 95% of cell cultures as determined by GFAP staining. Microglia are present as a contaminating cell type at a percentage of 3.6 ± 0.9% as determined by CD11B staining. For process induction experiments, cells are trypsinized and replated in DMEM with 1% fetal bovine serum. This low serum concentration is necessary for good adhesion of the cells. Pharmacological inhibitors are dissolved in DMSO and added 2 h later. P38 MAP kinase inhibitors SB202190 (Calbiochem) and the MEK inhibitor U0126 (Promega) are used at 20 µM. We previously determined that the inactive analog of SB 202190, SB202474 (Calbiochem) had no effects on pathway activation or astrocyte morphology. Therefore, the inactive drug analog will not be used in the array experiments. Final DMSO concentration in the drug treatments and vehicle controls is 0.2%. Human recombinant FGF2 (obtained from the National Cancer Institute Preclinical Repository) is used at 25 ng/ml, based on extensive dose/response analyses in our published work.
2008-06-15 | E-GEOD-6675 | biostudies-arrayexpress
Project description:Astrocytes, the most prominent glial cell type in the brain, send specialized processes called endfeet around blood vessels and express a large molecular repertoire regulating the cerebrovascular system physiology. One of the most striking properties of astrocyte endfeet is their enrichment in gap junction protein Connexin 43 and 30 (Cx43 and Cx30) allowing in particular for direct intercellular trafficking of ions and small signaling molecules through perivascular astroglial networks. In this study, we addressed the specific role of Cx30 at the gliovascular interface. Using an inactivation mouse model for Cx30 (Cx30Δ/Δ), we showed that absence of Cx30 does not affect blood-brain barrier (BBB) organization and permeability. However, it results in the cerebrovascular fraction, in a strong upregulation of Sgcg encoding g-Sarcoglycan (SG), a member of the Dystrophin-associated protein complex (DAPC) connecting cytoskeleton and the extracellular matrix. The same molecular event occurs in Cx30T5M/T5M mutated mice, where Cx30 channels are closed, demonstrating that Sgcg regulation relied on Cx30 channel functions. We further characterized the cerebrovascular Sarcoglycan complex (SGC) and showed the presence of α-, β-, δ-, γ-, ε- and ζ- SG, as well as Sarcospan. Altogether, our results suggest that the Sarcoglycan complex is present in the cerebrovascular system, and that expression of one of its members, g-Sarcoglycan, depends on Cx30 channels. As described in skeletal muscles, the SGC may contribute to membrane stabilization and signal transduction in the cerebrovascular system, which may therefore be regulated by Cx30 channel-mediated functions.
2015-03-03 | GSE59148 | GEO
Project description:The endoribonuclease, Dicer, is indispensible for generating the majority of mature microRNAs (miRNAs), which are posttranscriptional regulators of gene expression involved in a wide range of developmental and pathological processes in mammalian central nervous system. While functions of Dicer-dependent miRNA pathways in neurons and oligodendrocytes have been extensively investigated, little is known about the role of Dicer in astrocytes. Here we report the effect of Cre-loxP mediated conditional deletion of Dicer selectively from postnatal astroglia on brain development. Dicer-deficient mice exhibited normal motor development and neurological morphology prior to postnatal week 5. Thereafter mutant mice invariably developed a rapidly fulminant neurological decline characterized by ataxia, severe progressive cerebellar degeneration, seizures, uncontrollable movements and premature death by postnatal week 9-10. Integrated transcription profiling, histological and functional analyses of cerebella showed that deletion of Dicer in cerebellar astrocytes altered the transcriptome of astrocytes to be more similar to an immature or reactive-like state prior to the onset of neurological symptoms or morphological changes. As a result, critical and mature astrocytic functions including glutamate uptake and antioxidant pathways were substantially impaired, leading to massive apoptosis of cerebellar granule cells and degeneration of Purkinje cells. Collectively, our study demonstrates the critical involvement of Dicer in normal astrocyte maturation and maintenance. Our findings also reveal non-cell autonomous roles of astrocytic Dicer-dependent pathways in regulating proper neuronal functions and implicate that loss of or dysregulation of astrocytic Dicer-dependent pathways may be involved in neurodegeneration and other neurological disorders. Four replicate experiments using samples derived from biologically independent pairs of control (mGfap-Cre; Dicer +/flox) and Dicer mutant (mGfap-Cre; Dicer flox/flox) littermate mice (postnatal day 30) were performed with a dye-swap experimental design.
2011-05-10 | E-GEOD-28589 | biostudies-arrayexpress
Project description:Children with SOX2-deficiency develop anophthalmia/microphthalmia and display neurological impairment. Here we report an essential role for astroglial SOX2 in brain anomalies and neurological defects. Sox2-deficiency inhibited postnatal astrocyte maturation without affecting astroglial proliferation and population expansion. Mechanistically, we found that SOX2 directly bound to a cohort of astrocytic signature genes such as those involving in glutamate transport and that Sox2-deficiency remarkably reduced glutamate transporter expression and compromised astrocyte function of glutamate uptake. Behaviorally, astroglial Sox2-deficient mice developed hyperactivity in locomotion while their motor skills, social capability, and learning abilities were unaffected. We found that astroglial Sox2-deficiency results in elevated glutamatergic synapse formation and elevated excitability of striatal medium spiny neurons, which has been shown to trigger hyperactive locomotion. Our study provides new insights into the biological mechanisms underlying brain defects in children with SOX2 mutations and unveils a novel connection between astrocyte SOX2 and brain development and behavior.
2021-08-14 | GSE182032 | GEO
Project description:Brain postnatal development is characterized by critical periods of experience dependent remodeling. Maturation of local circuits inhibitory neurons terminate this period of enhanced plasticity. Astroglial cells are known to influence excitatory and inhibitory synaptic transmission as well as network activity through active signaling mechanisms. Although these can be developmentally regulated, the role of astrocytes in the timing of post-natal critical period is unknown. Here we show in the visual cortex that astrocytes con-trol the maturation of inhibitory neurons and thereby closure of the critical period. We uncover a novel underlying pathway involving regulation of the extracellular matrix that allows interneurons maturation via astroglial connexin signaling. We find that timing of the critical period closure is controlled by a marked upregulation of the astroglial protein connexin 30 that inhibits expression of the matrix degrading enzyme MMP9 through the RhoA-GTPase pathway. Our results thus demonstrate that astrocytes not only influ-ence neuronal activity but are also key elements in the experience–dependent wiring of brain circuits. Therefore, astrocytes represent a new cellular partner to consider in our understanding of the post-natal shaping of neuronal activities, hence providing a new target to alleviate malfunctions associated to im-paired closure of the critical period and settling of synaptic circuits.
2022-05-12 | PXD020448 | Pride