Microglia dynamics in health and disease
Ontology highlight
ABSTRACT:
PROVIDER: PRJEB18711 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Microglia, the resident immune cells of the central nervous system (CNS), are derived from yolk-sac macrophages that populate the developing CNS during early embryonic development. Once established, the microglia population is self-maintained throughout life by local proliferation. As a scalable source of microglia-like cells (MGLs), we here present a forward programming protocol for their generation from human pluripotent stem cells (hPSCs). The transient overexpression of PU.1 and C/EBPβ in hPSCs led to a homogenous population of mature microglia within 16 d. MGLs met microglia characteristics on a morphological, transcriptional, and functional level. MGLs facilitated the investigation of a human tauopathy model in cortical neuron–microglia cocultures, revealing a secondary dystrophic microglia phenotype. Single-cell RNA sequencing of microglia integrated into hPSC-derived cortical brain organoids demonstrated a shift of microglia signatures toward a more-developmental in vivo–like phenotype, inducing intercellular interactions promoting neurogenesis and arborization. Taken together, our microglia forward programming platform represents a tool for both reductionist studies in monocultures and complex coculture systems, including 3D brain organoids for the study of cellular interactions in healthy or diseased environments.
2022-09-16 | GSE207608 | GEO
Project description:Microglia are tissue macrophages of the central nervous system (CNS) that control tissue homeostasis, and as such they are crucially important for organ integrity. Microglia dysregulation is thought to be causal for a group of neuropsychiatric, neurodegenerative and neuroinflammatory diseases, called ‘microgliopathies’. However, how the intracellular stimulation machinery in microglia is controlled is poorly understood. By using expression studies, we identified the ubiquitin-specific protease (Usp) 18 in white matter microglia that essentially contributes to microglial quiescence under homeostatic conditions. We further found that microglial Usp18 negatively regulated the activation of STAT1 and concomitant induction of interferon-induced genes thereby disabling the termination of IFN signalling. Unexpectedly, the Usp18-mediated feedback loop was independent from the catalytic domain of the protease but instead required the interacting region of Ifnar2. Additionally, the absence of Ifnar1 completely rescued microglial activation indicating a tonic IFN signal mediated by receptor interactions under non-diseased conditions. Finally, conditional depletion of Usp18 only in myeloid cells significantly enhanced the disease burden in a mouse model of CNS autoimmunity, increased axonal and myelin damage and determined the spatial distributions of CNS lesions that shared the same STAT1 signature as myeloid cells found in active multiple sclerosis (MS) lesions. These results identify Usp18 as novel negative regulator of microglia activation, demonstrate a protective role of the IFNAR pathway for microglia and establish Usp18 as potential therapeutic target for the treatment of MS. Primary microglia (WT, USP18ko and USP18_C61A mice) and BV-2 cells (treated with control siRNA or siRNA against USP18) were incubated with 500 U/ml IFN-b. At different timepoints (0h, 6h, and 24h) RNA samples were taken and analyzed via Microarray
2015-04-20 | E-GEOD-61500 | biostudies-arrayexpress
Project description:Microglia are resident CNS immune cells that are active sensors in healthy brain and versatile effectors under pathological conditions. Cerebral ischemia induces a robust neuroinflammatory response that includes marked changes in the gene expression and phenotypic profile of a variety of endogenous CNS cell types (astrocytes, neurons, microglia) as well as an influx of leukocytic cells (neutrophils, macrophages, T-cells) from the periphery. Many molecules and conditions can trigger a transformation of ârestingâ (or surveying) microglia to an âactivatedâ (alerted/reactive) state. Here we review recent developments in the literature that relate to microglial activation in the experimental setting of in vitro and in vivo ischemia. We also present new data from our own laboratory demonstrating the direct effects of in vitro ischemic conditions on the microglial phenotype and genomic profile. Emphasis is placed on the role of specific molecular signaling systems such as hypoxia inducible factor-1 (HIF-1) and toll-like receptor-4 (TLR4) in regulating the microglial response in this setting. We then review histological and recent novel radiological data that confirms a key role for microglial activation in the setting of ischemic stroke in humans. We discuss recent progress in the pharmacological and molecular targeting of microglia in acute ischemic stroke. Finally, we explore how recent studies on ischemic preconditioning have increased interest in preemptively targeting microglial activation in order to reduce stroke severity. 12 arrays, 4 experimental groups, 3 replicates in each group, CN is control normoxia, CH is control hypoxia, TN is TLR4 knockout normoxia, TH is TLR4 knockout hypoxia.
2010-10-05 | E-GEOD-18602 | biostudies-arrayexpress
Project description:Microglia constitute a highly specialized network of tissue resident immune cells that is important for the control of tissue homeostasis and the resolution of virtually all diseases of the central nervous system (CNS). However, how this dissemination is established and maintained in vivo and its kinetics of these processes are poorly understood. Here we established a new multicolor fluorescence fate mapping system to monitor microglia dynamics during steady state and disease. Our findings that microglia establish a stable network over time albeit with regional differences and remarkably high turnover rates challenge their postulated longevity. Microglia self-renewal constitutes a random process without evidence of defined progenitor cells. Under pathological conditions this randomness shifts to clonal microglia expansion that is finally resolved by both cell apoptosis and egression for re-establishment of the stable microglia network. Our data reveal new insights on how microglia ensure their complex distribution throughout the healthy and diseased CNS .
2017-03-27 | GSE79252 | GEO
Project description:Microglia are the tissue macrophages of the central nervous system (CNS) and the first to respond to CNS dysfunction and disease. Gene expression profiling of microglia during development, under homeostatic conditions and in the diseased CNS provided insight in microglia functions and changes thereof. Single cell sequencing studies further contributed to our understanding of microglia heterogeneity in relation to age, sex and CNS disease. Recently, single nucleus gene expression profiling was performed on (frozen) CNS tissue. Transcriptomic profiling of CNS tissues by (single) nucleus RNA-sequencing has the advantage that it can be applied to archived and well stratified frozen specimens. Here, we give an overview of the significant advances recently made in microglia transcriptional profiling. In addition, we present matched cellular and nuclear microglia RNA-seq datasets we generated from mouse and human CNS tissue to compare cellular versus nuclear transcriptomes from fresh and frozen samples. We demonstrate that microglia can be similarly profiled with cell and nucleus profiling, and importantly also with nuclei isolated from frozen tissue. Nuclear microglia transcriptomes are a reliable proxy for cellular transcriptomes. Interestingly, lipopolysaccharide- (LPS)-induced changes in gene expression were even more pronounced in the nuclear transcriptome. In addition, heterogeneity in microglia observed in fresh samples is similarly detected in frozen nuclei of the same donor. Together, these results show that microglia nuclear RNAs obtained from frozen CNS tissue are a reliable proxy for microglia gene expression and cellular heterogeneity and may prove an effective strategy to study of the role of microglia in neuropathology.
2019-08-10 | GSE135618 | GEO
Project description:Microglia play critical roles in neural development and homeostasis. They are also implicated in neurodegenerative and neuroinflammatory diseases of the central nervous system (CNS). However, little is known about the presence of spatially and temporally restricted subclasses of microglia during CNS development and disease. Here, we combined massively parallel single-cell analysis, single-molecule FISH, advanced immunohistochemistry and computational modelling to comprehensively characterize novel microglia subclasses, which were transcriptionally different from perivascular macrophages, in up to six different CNS regions during development and diseases. Single-cell analysis revealed specific time- and region-dependent microglia subtypes during homeostasis. In contrast, demyelinating and neurodegenerative diseases evoked context-dependent microglia subtypes with distinct molecular hallmarks and diverse cellular kinetics. Finally, diverse microglia subsets were also identified in normal and diseased human brains. Our data provide new insights into the CNS endogenous immune system during development, health and perturbations.
2019-02-13 | GSE124335 | GEO
Project description:Microglia are the resident macrophages of the central nervous system (CNS). Gene profiling identified the transcriptional regulator Sall1 as a microglia signature gene. Given the high expression of Sall1 in microglia, we sought to identify its function in vivo. The Sall1CreER allele has been targeted into the Sall1 locus, therefore Sall1CreER/fl mice (heterozygous for both alleles) allow inducible ablation of Sall1 expression in microglia after tamoxifen treatment. We performed RNA-seq to examine gene expression profiles of microglia sorted from tamoxifen treated adult Sall1CreER/fl mice and Sall1fl/fl control littermates. Microglia were obtained with > 98% purity and the absence of Sall1 was confirmed in Sall1CreER/fl microglia. We could show that deletion of Sall1 in microglia in vivo resulted in the conversion of these cells from resting tissue macrophages into inflammatory phagocytes leading to altered neurogenesis and disturbed tissue homeostasis. Similar changes in gene expression profiles were found in Sall1-deficient microglia isolated from tamoxifen-treated Cx3cr1CreERSall1fl/fl mice. In these mice, deletion of Sall1 is targeted to CX3CR1+ myeloid cells including microglia and CNS-associated macrophages but not to any other CNS-resident cells. This indicated that Sall1 transcriptional regulation maintains microglia identity and physiological properties in the CNS.
2016-10-19 | E-MTAB-5077 | biostudies-arrayexpress
Project description:Expression profiling of distinct central nervous system (CNS) cell populations has been employed to facilitate disease classification and to provide insights into the molecular basis of brain pathology. One important cell type implicated in a wide variety of CNS disease states is the resident brain macrophage (microglia). In these studies, microglia are often isolated from dissociated brain tissue by flow sorting procedures [fluorescence-activated cell sorting (FACS)] or from postnatal glial cultures by mechanic isolation. Given the highly dynamic and state-dependent functions of these cells, the use of FACS or short-term culture methods may not accurately capture the biology of brain microglia. In the current study, we performed RNA-sequencing using Cx3cr1+/GFP labeled microglia isolated from the brainstem of 6-week-old mice to compare the transcriptomes of FACS-sorted versus laser capture microdissection (LCM). While both isolation techniques resulted in a large number of shared (common) transcripts, we identified transcripts unique to FACS-isolated and LCM-captured microglia. In particular, M-bM-^HM-<50% of these LCM-isolated microglial transcripts represented genes typically associated with neurons and glia. While these transcripts clearly localized to microglia using complementary methods, they were not translated into protein. Following the induction of murine experimental autoimmune encephalomyelitis, increased oligodendrocyte and neuronal transcripts were detected in microglia, while only the myelin basic protein oligodendrocyte transcript was increased in microglia after traumatic brain injury. Collectively, these findings have implications for the design and interpretation of microglia transcriptome-based investigations. Wildtype and GFP expressing microglia from mouse brainstems were flow sorted or captured by laser microdissection. Differences between the two isolation methods were verified and further examined in neurodegenerative disease models.
2015-01-30 | E-GEOD-53789 | biostudies-arrayexpress
Project description:During early embryogenesis microglia arise from yolk sac progenitors populating the developing CNS, where they are maintained as tissue-resident macrophages throughout the organism’s lifespan. Here, we describe an experimental system that allows the specific conditional ablation of microglia in vivo. Strikingly, we found that the microglia compartment was reconstituted within one week following depletion. Microglia repopulation relied entirely on a CNS-resident, internal pool and was independent from bone marrow-derived precursors. Newly formed microglia were found in highly proliferative, organized micro-clusters that dissolve once steady state was achieved. Gene expression profiling revealed prominent expression of Interleukin-1 (IL-1) receptor in proliferating microglia. During the repopulation phase, IL-1 signaling was neutralized by treatment with IL-1 receptor antagonist that impaired microglia proliferation. Hence, microglia harbor a highly efficient potential to restore themselves without contribution of peripheral myeloid cells. IL-1 signaling significantly participates in this restorative proliferation process and is involved in stabilizing microglia maintenance. bone marrow macrophages, wild type microglia, and repopulating microglia
2015-07-15 | E-GEOD-68376 | biostudies-arrayexpress
Project description:Microglia are tissue macrophages of the central nervous system (CNS) that control tissue homeostasis, and as such they are crucially important for organ integrity. Microglia dysregulation is thought to be causal for a group of neuropsychiatric, neurodegenerative and neuroinflammatory diseases, called ‘microgliopathies’. However, how the intracellular stimulation machinery in microglia is controlled is poorly understood. By using expression studies, we identified the ubiquitin-specific protease (Usp) 18 in white matter microglia that essentially contributes to microglial quiescence under homeostatic conditions. We further found that microglial Usp18 negatively regulated the activation of STAT1 and concomitant induction of interferon-induced genes thereby disabling the termination of IFN signalling. Unexpectedly, the Usp18-mediated feedback loop was independent from the catalytic domain of the protease but instead required the interacting region of Ifnar2. Additionally, the absence of Ifnar1 completely rescued microglial activation indicating a tonic IFN signal mediated by receptor interactions under non-diseased conditions. Finally, conditional depletion of Usp18 only in myeloid cells significantly enhanced the disease burden in a mouse model of CNS autoimmunity, increased axonal and myelin damage and determined the spatial distributions of CNS lesions that shared the same STAT1 signature as myeloid cells found in active multiple sclerosis (MS) lesions. These results identify Usp18 as novel negative regulator of microglia activation, demonstrate a protective role of the IFNAR pathway for microglia and establish Usp18 as potential therapeutic target for the treatment of MS.
2015-04-20 | GSE61500 | GEO