Transcriptomic changes upon the formation of a functional "on demand" degradation network in microglia I
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE152100 | GEO | 2021/09/28
REPOSITORIES: GEO
Similar Datasets
Project description:We report the exchange of alpha-synuclein aggregates from one cell to another and examined transcriptomic changes following protein exchange. Differential expression (DE) analysis comparing alpha-synuclein-treated with untreated microglia identified alpha-synuclein induceable genes which were linked to inflammation, apoptosis, ER stress and intracellular protein targeting, while downregulated genes included categories related to mitosis, cytoskeleton and vesicle mediated transport. Co-culturing alpha-synuclein treated with untreated microglia largely suppressed the inflammatory and apoptotic phenotype of microglia thereby rescuing cells from cell death. Most importantly, these transprictomic changes were prevented by co-culturing the cells without direct cell-cell contact (transwell).
2021-09-28 | GSE166127 | GEO
Project description:We performed RNAseq using whole Drosophila heads after expressing human wild type alpha synuclein in either glia, neurons, or both types. We identified many upregulated genes when alpha synuclein was expresed in glia and many downregulated genes with it was expresed in neurons or both cell types.
2019-09-30 | GSE128120 | GEO
Project description:The synaptic protein α-synuclein is linked through genetics and neuropathology to the pathogenesis of Parkinson’s disease and related disorders. However, the mechanisms by which α-synuclein influences disease onset and progression are incompletely understood. To identify novel pathways and potential therapeutic targets we performed proteomic analysis in a highly penetrant new Drosophila model of α-synucleinopathy. We identified 476 significantly upregulated and 563 significantly downregulated proteins in heads from α-synucleinopathy model flies compared to controls. We then used multiple complementary analyses to identify and prioritize genes and pathways within the large set of differentially expressed proteins for functional studies. We performed Gene Ontology enrichment analysis, integrated our proteomic changes with human Parkinson’s disease genetic studies, and compared the α-synucleinopathy proteome with that of tauopathy model flies, which are relevant to Alzheimer’s disease and related disorders. These approaches identified GTP cyclohydrolase (GCH1) and folate metabolism as candidate mediators of α-synuclein neurotoxicity. In functional validation studies we found that knockdown of Drosophila Gch1 enhanced locomotor deficits in α-synuclein transgenic flies, while folate supplementation protected from α-synuclein toxicity. Our integrative analysis suggested that mitochondrial dysfunction was a common downstream mediator of neurodegeneration. Accordingly, Gch1 knockdown enhanced metabolic dysfunction in α-synuclein transgenic fly brains while folate supplementation partially normalized whole brain bioenergetics. Here we outline and implement an integrative approach to identify and validate potential therapeutic pathways using comparative proteomics and genetics and capitalizing on the facile genetic and pharmacological tools available in Drosophila.
2021-09-09 | PXD021312 | Pride
Project description:Abnormal accumulation of aggregated proteins and sustained microglial activation are important contributors of neurodegenerative process in neurological diseases. Recent studies have shown that aggregation-prone proteins, such as a-synuclein, the protein implicated in Parkinson’s disease (PD), are released from neuronal cells and thus present in the extracellular fluid, pointing to the possible paracrine effects of these proteins on microglial immune responses. However, the mechanism underlying the disease-associated microglial activation and the role of neuronal proteins in this process remain unknown. Here, we show that extracellular a-synuclein released from neuronal cells is an endogenous ligand of toll-like receptor 2 (TLR2) and activates microglia, which in turn induces neurodegeneration. Interaction between neuron-released a-synuclein and TLR2 and subsequent activation of the TLR2 signaling were demonstrated comprehensively by using computational modeling of signaling network and by the experimental validation in TLR2-deficient microglia both in vitro and in vivo. In contrast to the neuron-released a-synuclein, recombinant a-synuclein proteins, including monomer, oligomer, fibril, or nitrated forms, were not able to interact or activate TLR2, suggesting that neuronal cells have a mechanism of enriching specific forms of a-synuclein capable of activating TLR2 during the process of releasing this protein. Taken together, the results suggest that both neuron-released extracellular a-synuclein and TLR2 might be novel therapeutic targets for modifying neuroinflammation in PD and related neurodegenerative diseases. We collected culture media from differentiated SH-SY5Y cells overexpressing either human a-synuclein (alpha-SCM) or beta-galactosidase (LZCM) and treat these media to primary rat microglia at the concentration of a-synuclein of 1.1M. Transcriptome analyses with microglial cells treated with either aSCM or LZCM at two different time points, 6 h and 24 h.
2013-02-28 | E-GEOD-26532 | biostudies-arrayexpress
Project description:Alpha-synuclein aggregates (αSynAgg) are pathological hallmarks of Parkinson’s disease (PD) that induce microglial activation and immune-mediated neurotoxicity, although the molecular mechanisms of αSynAgg-induced immune activation are poorly defined. We used mass spectrometry to define proteomic changes induced by αSynAgg using in-vitro mouse microglia and an in-vivo fly (Drosophila melanogaster) model with neuron-specific αSyn overexpression. In mouse microglia, αSynAgg induced robust pro-inflammatory activation (increased expression of 864 genes including Irg1, Ifit1 and Pyhin) and increased nuclear proteins involved in RNA synthesis, splicing and anti-viral defense mechanisms. Conversely, αSynAgg decreased expression of 530 proteins (including Cdc123, Sod1 and Grn), which were predominantly cytosolic and involved in antigen presentation as well as metabolic, proteosomal and lysosomal mechanisms. Pathway analyses and confirmatory in -vitro studies suggested that αSynAgg partly mediates its effects via Stat3 activation. 26 proteins differentially-expressed by αSynAgg were also identified as PD risk genes in genome-wide association studies (upregulated: Brd2, Clk1, Siglec1; down-regulated: Memo1, Arhgap18, Fyn and PGgrn/Grn). We then validated progranulin (PGrn/Grn) as a lysosomal PD-associated protein that is decreased in striatal and nigral microglia in post-mortem PD brain compared to non-disease controls, congruent with our in -vitro findings.
2020-01-24 | PXD013691 | Pride
Project description:Protein kinase CK2 alpha prime (CK2a') is preferentially upregulated in the striatum of patients with HD and in different cellular and mouse models of HD. CK2a' happloinsufficiency in the zQ175 HD mouse model restored several HD-like phenotypes. We hypothesized that CK2a' neuronal up-regulation is linked to key transcriptional alterations in the zQ175 mouse model. We found that CK2a' haploinsufficiency rescued the expression of genes associated with synaptogenesis and glutamatergic signaling whose upstream regulator seems to be alpha-synuclein. These transcriptomic studies revealed a conection between CK2a', alpha-synuclein dysfunction and transcriptional changes in key signaling pathways.
2022-06-23 | GSE160586 | GEO
Project description:Background: Cell-to-cell propagation of α-synuclein (α-syn) aggregates is thought to contribute to the pathogenesis of Parkinson’s disease (PD) and underlie the spread of α-syn neuropathology. Increased pro-inflammatory cytokine levels and activated microglia are present in PD and activated microglia can promote α-syn aggregation. However, it is unclear how microglia influence α-syn cell-to-cell transfer. Methods: We developed a clinically relevant mouse model to monitor α-syn prion-like propagation between cells; we transplanted wild-type mouse embryonic midbrain neurons into a mouse striatum overexpressing human α-syn (huα-syn) following adeno-associated viral injection into the substantia nigra. In this system, we depleted or activated microglial cells and determined the effects on the transfer of huα-syn from host nigrostriatal neurons into the implanted dopaminergic neurons, using the presence of huα-syn within the grafted cells as a readout. Results: First, we compared α-syn cell-to-cell transfer between host mice with a normal number of microglia to mice in which we had pharmacologically ablated 80% of the microglia from the grafted striatum. With fewer host microglia, we observed increased accumulation of huα-syn in grafted dopaminergic neurons. Second, we assessed the transfer of α-syn into grafted neurons in the context of microglia activated by one of two stimuli, lipopolysaccharide (LPS) or interleukin-4 (IL-4). LPS exposure led to a strong activation of microglial cells (as determined by microglia morphology and cytokine production) and significantly higher amounts of huα-syn in grafted neurons. In contrast, injection of IL-4 did not change the proportion of grafted dopamine neurons that contained huα-syn relative to controls. RNA sequencing analysis revealed differential gene expression between LPS and IL-4 injected mice; many genes were upregulated in LPS including those involved with the inflammatory response. Conclusions: The absence or the hyperstimulation of microglia affected α-syn transfer in the brain. Our results suggest that under resting, non-inflammatory conditions, microglia modulate the transfer of α-syn. Pharmacological regulation of neuroinflammation could represent a future avenue for limiting the spread of PD neuropathology.
2019-08-12 | GSE130683 | GEO
Project description:A key process of neurodegeneration in Parkinson's disease (PD) is the transneuronal spreading of alpha-synuclein. Alpha-synuclein is a presynaptic protein that is implicated in the pathogenesis of PD and other synucleinopathies, where it forms, upon intracellular aggregation, pathological inclusions. Other hallmarks of PD include neurodegeneration and microgliosis in susceptible brain regions. Whether it is primarily transneuronal spreading of a-synuclein particles, inclusion formation, or other mechanisms, such as inflammation, that cause neurodegeneration in PD is unclear. We used spreading/aggregation of alpha-synuclein induced by intracerebral injection of a-synuclein preformed fibrils into the mouse brain to address this question. We performed quantitative histological analysis for a-synuclein inclusions, neurodegeneration, and microgliosis in different brain regions, and a gene expression profiling of the ventral midbrain, at two different timepoints after disease induction. We observed significant neurodegeneration and microgliosis in brain regions not only with, but also withouta-synuclein inclusions. We also observed prominent microgliosis in injured brain regions that did not correlate with neurodegeneration nor with inclusion load. In longitudinal gene expression profiling experiments, we observed early and unique alterations linked to microglial mediated inflammation that preceded neurodegeneration, indicating an active role of microglia in inducing neurodegeneration. Our observations indicate that a-synuclein inclusion formation is not the major driver in the early phases of PD-like neurodegeneration, but that diffusible, oligomeric a-synuclein species, which induce unusual microglial reactivity, play a key role in this process.
2020-11-02 | GSE155716 | GEO
Project description:Although α-synucleinis implicated in the pathogenesis of Parkinson’s disease and related disorders, it remains unclear whether specific conformations or levels of α-synuclein assemblies are toxic and how they cause progressive loss of human dopaminergic neurons. To address this issue, we used iPSC-derived dopaminergic neurons with a-synuclein triplication or controls where endogenous α-synuclein was imprinted into synthetic or disease-relevant conformations. We used α-synuclein fibrils generated de novo or amplified from homogenates of brains affected with Parkinson’s disease (n=3) .We found that a 2.5-fold increase in α-synuclein levels in α-synuclein gene triplication neurons promoted seeded aggregation in a dose and time-dependent fashion, which was associated with a further increase in α-synuclein gene expression.Transcriptomic analysis and isogenic correction of α-synuclein triplication revealed that intraneuronal α-synuclein levels solely and sufficiently explained vulnerability to cell death.
2020-09-02 | GSE149632 | GEO
Project description:Type I interferons (IFN-I) are crucial for effective antimicrobial defence in the central nervous system (CNS) but also can cause severe neurological disease (termed cerebral interferonopathy) as exemplified by Aicardi-Goutières Syndrome and chronic viral infection. In the CNS, microglia and astrocytes have essential roles in host responses to infection and injury, with both cell types responding to IFN-I. However, the extent to which the IFN-I responses of these cells differ, if at all, is still unknown. Here we determined the global transcriptional responses of astrocytes and microglia to the IFN-I, IFN-alpha. MGCs were prepared from 2–4 day-old C57BL/6 mice. Purified primary astrocytes were obtained from the MGCs by magnetic activated cell sorting using anti-CD11b beads. Microglia were obtained from mixed glial cell cultures by mechanical shaking for 4 h. After treating astrocytes and microglia with IFN-alpha for 12 h, microarray using Affymetrix mouse genome array 430 2.0 array was performed on total RNA extracted from these cells. We found that under basal conditions, each cell type has a unique gene expression pattern reflective of its developmental origin and biological function. Following stimulation with IFN-alpha for 12 h, astrocytes and microglia also displayed a common core response that was characterized by the increased expression of genes required for pathogen detection and elimination. Microglia had a more extensive and diverse response to IFN-alpha with twice the number of genes upregulated (282 vs. 141 genes) when compared with astrocytes. Validation of the findings in vivo further suggested that astrocytes and microglia play important but distinct roles in the development of IFN-alpha-driven cerebral interferonopathies.
2018-03-18 | E-MTAB-6301 | biostudies-arrayexpress