Loss of Fatty Acid Degradation by Astrocytic Mitochondria Triggers Neuroinflammation and Neurodegeneration
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE203234 | GEO | 2023/02/01
REPOSITORIES: GEO
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Project description:Loss of Fatty Acid Degradation by Astrocytic Mitochondria Triggers Neuroinflammation and Neurodegeneration
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Project description:Astrocyte activation is a common feature of neurodegenerative diseases. However, the ways in which dying neurons influence the activity of astrocytes is poorly understood. RIPK3 signaling has recently been described as a key regulator of neuroinflammation, but whether this kinase mediates astrocytic responsiveness to neuronal death has not yet been studied. Here, we used the MPTP model of Parkinson’s disease to show that activation of astrocytic RIPK3 drives dopaminergic cell death and axon damage. Transcriptomic profiling revealed that astrocytic RIPK3 promoted gene expression associated with neuroinflammation and movement disorders, and this coincided with significant engagement of DAMP signaling. Using human cell culture systems, we show that factors released from dying neurons signal through RAGE to induce RIPK3-dependent astrocyte activation. These findings highlight a mechanism of neuron-glia crosstalk in which neuronal death perpetuates further neurodegeneration by engaging inflammatory astrocyte activation via RIPK3.
2024-04-05 | GSE237891 | GEO
Project description:Neuronal DAMPs exacerbate neurodegeneration via astrocytic RIPK3 signaling
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Project description:In neurodegenerative diseases, debris of dead neurons are thought to trigger glia-mediated neuroinflammation, thus increasing neuronal death. Here we show that the expression of neurotoxic proteins associated with these diseases in microglia alone is sufficient to directly trigger death of naive neurons and to propagate neuronal death through activation of naive astrocytes to the A1 state. Injury propagation is mediated, in great part, by the release of fragmented and dysfunctional microglial mitochondria into the neuronal milieu. The amount of damaged mitochondria released from microglia relative to functional mitochondria and the consequent neuronal injury are determined by Fis1-mediated mitochondrial fragmentation within the glial cells. The propagation of the inflammatory response and neuronal cell death by extracellular dysfunctional mitochondria suggests a potential new intervention for neurodegeneration-one that inhibits mitochondrial fragmentation in microglia, thus inhibiting the release of dysfunctional mitochondria into the extracellular milieu of the brain, without affecting the release of healthy neuroprotective mitochondria.
| S-EPMC6764589 | biostudies-literature
Project description:In this study, by a genome-wide RNA interference screen, we identified heterogeneous nuclear ribonucleoprotein U (Hnrnpu) as an endogenous key molecule in astrocyte activation. Inhibition of Hnrnpu in astrocytes impairs the formation of astrocytic glial scar, motor function recovery, and neuronal regeneration after spinal cord injury (SCI) in mice. Therefore, we then performed gene expression profiling analysis to evalute the function of HNRNPU in human astrocytes. Our findings uncover that modulation of endogenous astrocytic function through Hnrnpu would be a promising therapeutic avenue to restore neurological function after the injury.
2025-01-28 | GSE236433 | GEO
Project description:Analysis of astrocytic gene expression profiles after ischemic stroke. Stroke is a complicated disease caused by the interaction of multiple celltypes. Results provide new insights into the molecular mechanisms underlying astrocytic activation after ischemic stroke.
2024-05-23 | GSE238125 | GEO
Project description:A strocytes are essential for synapse formation, maturation and plasticity, yet their function during developmental neuronal remodeling is largely unknown To identify astrocytic molecules required for axon pruning of mushroom body ( γ neurons in Drosophi la we profile d the expression of astrocytes before ( and after ( remodeling. F ocus ing on genes enriched in larval astrocytes we identified 12 genes that are required in astrocytes, for axon pruning including the F actin regulat ors Arpc1 and form3 Interestingly, perturbing astrocytic actin dynamics did not affect their gross morphology migration or TGF β secretion In contrast, actin dynamics was required for astrocyte infiltration into the axon bundle at the onset of pruning. Remarkably, decreasing axonal adhesion facilitated the infiltration of Arpc1 KD astrocytes, and suppressed the pruning defect driven by the astrocytic perturbation Together, our findings suggest that actin dependent astrocytic infiltration is a key step in axon pruning thus promoting our understanding of neuron glia interactions during remodeling
2023-02-12 | GSE190743 | GEO
Project description:Genomic aberrations were determined by array-based comparative genomic hybridization in 131 diffuse astrocytic gliomas, including 87 primary glioblastomas (pGBIV), 13 secondary glioblastomas (sGBIV), 19 anaplastic astrocytomas (AAIII), and 12 diffuse astrocytomas (AII). Expression profiling was performed for 74 tumors (42 pGBIV, 11 sGBIV, 13 AAIII, 8 AII). 131 aCGH experiments. 87 EP experiments (x2 dye swap). DNA and RNA extracted from the same patients.
2010-09-14 | E-GEOD-18166 | biostudies-arrayexpress
Project description:BACKGROUND:Neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease dementia (PDD), and frontotemporal lobar dementia (FTLD) are characterized by progressive neuronal loss but differ in their underlying pathological mechanisms. However, neuroinflammation is commonly observed within these different forms of dementia. Recently, it has been suggested that an altered sphingolipid metabolism may contribute to the pathogenesis of a variety of neurodegenerative conditions. Especially ceramide, the precursor of all complex sphingolipids, is thought to be associated with pro-apoptotic cellular processes, thereby propagating neurodegeneration and neuroinflammation, although it remains unclear to what extent. The current pathological study therefore investigates whether increased levels of ceramide are associated with the degree of neuroinflammation in various neurodegenerative disorders. METHODS:Immunohistochemistry was performed on human post-mortem tissue of PDD and FTLD Pick's disease cases, which are well-characterized cases of dementia subtypes differing in their neuroinflammatory status, to assess the expression and localization of ceramide, acid sphingomyelinase, and ceramide synthase 2 and 5. In addition, we determined the concentration of sphingosine, sphingosine-1-phosphate (S1P), and ceramide species differing in their chain-length in brain homogenates of the post-mortem tissue using HPLC-MS/MS. RESULTS:Our immunohistochemical analysis reveals that neuroinflammation is associated with increased ceramide levels in astrocytes in FTLD Pick's disease. Moreover, the observed increase in ceramide in astrocytes correlates with the expression of ceramide synthase 5. In addition, HPLC-MS/MS analysis shows a shift in ceramide species under neuroinflammatory conditions, favoring pro-apoptotic ceramide. CONCLUSIONS:Together, these findings suggest that detected increased levels of pro-apoptotic ceramide might be a common denominator of neuroinflammation in different neurodegenerative diseases.
| S-EPMC6388480 | biostudies-other
Project description:Diffuse gliomas represent the most prevalent class of primary brain tumor. Despite significant recent advances in the understanding of glioblastoma (WHO IV), its most malignant subtype, lower-grade (WHO II and III) glioma variants remain comparatively understudied, especially in light of their notably variable clinical behavior. To examine the foundations of this heterogeneity, we performed multidimensional molecular profiling, including global transcriptional analysis, on 101 lower-grade diffuse astrocytic gliomas collected at our own institution, and validated our findings using publically available gene expression and copy number data from large independent patient cohorts. We found that IDH mutational status delineated molecularly and clinically distinct glioma subsets, with IDH mutant (IDH mt) tumors exhibiting TP53 mutations, PDGFRA overexpression, and prolonged survival, and IDH wild-type (IDH wt) tumors exhibiting EGFR amplification, PTEN loss, and unfavorable disease outcome. Furthermore, global expression profiling revealed three robust molecular subclasses within lower-grade diffuse astrocytic gliomas, two of which were predominantly IDH mt and one almost entirely IDH wt. IDH mt subclasses were distinguished from each other on the basis of TP53 mutations, DNA copy number abnormalities, and links to distinct stages of neurogenesis in the subventricular zone (SVZ). This latter finding implicates discrete pools of neuroglial progenitors as cells of origin for the different subclasses of IDH mt tumors. In summary, we have elucidated molecularly distinct subclasses of lower-grade diffuse astrocytic glioma that dictate clinical behavior and demonstrate fundamental associations with both IDH mutational status and neuroglial developmental stage. 80 tumor samples, one normal tissue sample (brain)
2012-02-24 | E-GEOD-35158 | biostudies-arrayexpress