Single-cell transcriptomics reveals microglia heterogeneity across the nigrostriatal pathway
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE148393 | GEO | 2021/03/22
REPOSITORIES: GEO
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Project description:Single-cell transcriptomics reveals microglia heterogeneity across the nigrostriatal pathway
| PRJNA624131 | ENA
Project description:Microglia are specialized parenchymal-resident phagocytes of the central nervous system (CNS) that actively support, defend and modulate the neural environment. Dysfunctional microglia responses are believed to worsen CNS diseases, nevertheless their impact during the neuroinflammatory processes remains largely obscure. Here, using a combination of multicolor flow cytometry and single-cell RNA sequencing, we comprehensively profiled microglia in the brain of lipopolysaccharide (LPS)-injected mice. By excluding the contribution of other immune CNS-resident and peripheral cells, we showed that microglia isolated from LPS-injected mice displayed a global downregulation of their homeostatic signature together with an upregulation of inflammatory genes. Notably, we identified distinct microglia activated profiles under inflammatory conditions, which greatly differ from neurodegenerative disease-associated profiles. These results provide insights into microglia heterogeneity and establish a resource for the identification of specific phenotypes in CNS disorders, such as neuroinflammatory and neurodegenerative diseases.
2018-09-10 | GSE115571 | GEO
Project description:Parkinson’s disease (PD) is characterized by the aggregation of α-synuclein into Lewy bodies and Lewy neurites in the brain. Microglia-driven neuroinflammation may contribute to neuronal death in PD, however the exact role of microglia remains unclear and has been understudied. The A53T mutation in the gene coding for α-synuclein has been linked to early-onset PD, and exposure to A53T-mutant human α-synuclein increases the potential for inflammation of murine microglia. To date, its effect has not been studied in human microglia. We aimed to study the impact of the A53T mutation on human microglia developed in a physiologically relevant context Here, we used 2-dimensional cultures of human iPSC-derived microglia and transplantation of these cells into the mouse brain to assess the effects of the A53T mutation on human microglia. We found that A53T-mutant human microglia had an intrinsically increased propensity towards pro-inflammatory activation upon inflammatory stimulus. Additionally, A53T mutant microglia showed increased oxidative stress, with a strong decrease in catalase expression in non-inflammatory conditions. Together, these results indicate that A53T mutant human microglia display cell-autonomous phenotypes that may worsen neuronal damage in early-onset PD.
2024-08-20 | GSE241437 | 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:Understanding the respective role of microglia and infiltrating monocytes in neuroinflammatory conditions has recently seemed possible by the identification of a specific microglia signature. Here instead we provide evidence that peripheral macrophages may express some of the most commonly described microglia markers at some developmental stages or pathological conditions, in particular during chronic neuroinflammation. Further, our data support the hypothesis about phenotypic plasticity and convergence among distinct myeloid cells so that they may act as a functional unit rather than as different entities, boosting their mutual functions in different phases of disease. This holds relevant implications in the view of the growing use of myeloid cell therapies to treat brain disease in humans.
2020-10-12 | E-MTAB-8059 | biostudies-arrayexpress
Project description:In the brain the cells that control inflammation are called a type of white blood cell called microglia. Microglia are located throughout the brain and spinal cord and account for 10–15% of all cells found within the brain. As the resident white blood cells, they are the main active immune defence in the central nervous system (CNS). Microglia are part of an important class of cells known as macrophages that have two main states: M1 and M2. M1 cells are pro- inflammatory, leading to more inflammation, while M2 are anti-inflammatory, and drive wound healing. In this study, we will collect primary microglia from surgical biospies of 100 individuals.
This data is part of a pre-publication release. For information on the proper use of pre-publication data shared by the Wellcome Trust Sanger Institute (including details of any publication moratoria), please see http://www.sanger.ac.uk/datasharing/
| EGAS00001002494 | EGA
Project description:Microglia are the resident immune effector cells of the central nervous system (CNS) rapidly reacting to various pathological stimuli to maintain CNS homeostasis. However, microglial reactions in the CNS may also worsen neurological disorders. Hence, the phenotypic analysis of microglia in healthy tissue may identify specific poised subsets ultimately supporting or harming the neuronal network. This is all the more important for the understanding of CNS disorders exhibiting regional-specific and cellular pathological hallmarks, such as many neurodegenerative disorders, including Parkinson's disease (PD). In this context, we aimed to address the heterogeneity of microglial cells in susceptible brain regions for PD, such as the nigrostriatal pathway. Here, we combined single-cell RNA-sequencing with immunofluorescence analyses of the murine nigrostriatal pathway, the most affected brain region in PD. We uncovered a microglia subset, mainly present in the midbrain, displaying an intrinsic transcriptional immune alerted signature sharing features of inflammation-induced microglia. Further, an in situ morphological screening of inferred cellular diversity showed a decreased microglia complexity in the midbrain when compared to striatum. Our study provides a resource for the identification of specific microglia phenotypes within the nigrostriatal pathway, which may be relevant in PD.
| S-EPMC8039119 | biostudies-literature
Project description:Advances in large-scale proteomics analysis have been very useful in understanding pathogenesis of diseases and elaborating therapeutic strategies. Proteomics has been employed to study Parkinson’s disease (PD), however, sparse studies reported proteome investigation after cell therapy approaches. In this study, we used liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify differentially expressed proteins in a mouse model of PD after cell therapy. Proteins were extracted from five nigrostriatal-related brain regions of mice previously lesioned with 6-hydroxydopamine (6-OHDA) in the substantia nigra (SN). Protein expression was compared in non-grafted brain to 1 and 7 days after intranigral grafting of E12.5 embryonic ventral mesencephalon (VM). We found a total of 277 deregulated proteins after transplantation, which are known to be involved in lipid metabolism, oxidative phosphorylation and PD; thus, confirming that our animal model is similar to human PD and that the presence of grafted cells modulates the expression of these proteins. Notably, 7 proteins were commonly downregulated in all selected brain regions after engraftment, including Acta1, Atp6v1e1, Eci3, Lypla2, Pip4k2a, Sccpdh and Sh3gl2. These are known to be involved in the formation of lipids and recycling of dopamine (DA) vesicle at the synapse. Moreover, intranigral transplantation of VM cells decreased the expression of proteins related to oxidative stress, especially in the nigrostriatal pathway containing the DA grafted neurons. In the same regions, an upregulation of several proteins including alpha-synuclein and tyrosine hydroxylase were observed, whereas expression of tetraspanin 7 was shut down. Overall, these results suggest that intranigral transplantation of VM tissue in an animal model of PD may induce a decrease of oxidative stress in the nigrostriatal pathway and a restoration of the machinery of neurotransmitters, particularly dopamine release to promote DA transmission through a decrease of D2 dopamine receptors endocytosis. Identification of new mechanistic elements involved in the nigrostriatal reconstruction process is a promising approach to enhance the repair of this pathway in PD patients undergoing cell therapy.
2021-03-08 | PXD022193 | Pride
Project description:Microglia are brain-resident, myelin-phagocytosing cells, yet their role in lesion initiation in grey and white matter regions in multiple sclerosis (MS) is unclear. We isolated primary microglia from both, occipital cortex and corpus callosum, of 10 MS and 11 control donors and studied their transcriptional profile by RNA sequencing, thereby identifying regional and MS-associated changes. Identification of pathways underlying regional differences showed a relatively increased type I interferon response in cortical grey matter microglia, while white matter microglia more highly expressed NF-κB pathway genes. In normal-appearing white matter MS tissue, lipid metabolism genes were increased, suggesting processing of myelin by microglia already in areas seemingly devoid of MS pathology. Normal-appearing grey matter MS microglia showed increased activation of glycolysis and metal ion homeostasis, possibly reflecting microglia reacting to iron depositions. Notably, expression of genes associated with microglia homeostasis were hardly changed, suggesting that subtle regional changes in MS-associated microglia do not yet affect their resting state.
2019-03-13 | GSE111972 | GEO
Project description:Rasmussen encephalitis (RE) is a rare childhood neurological disease characterized by progressive unilateral loss of function, hemispheric atrophy and drug-resistant epilepsy. Affected brain tissue shows signs of infiltrating cytotoxic T-cells, microglial activation, and neuronal death, implicating an inflammatory disease process. Recent studies have identified molecular correlates of inflammation in RE, but cell-type-specific mechanisms remain unclear. We used single-nucleus RNA-sequencing (snRNA-seq) to assess gene expression across multiple cell types in brain tissue resected from two children with RE. We found transcriptionally distinct microglial populations enriched in RE compared to two age-matched individuals with unaffected brain tissue and two individuals with Type I focal cortical dysplasia (FCD). Specifically, microglia in RE tissues demonstrated upregulation of genes associated with cytokine signaling, interferon-mediated pathways, and T-cell activation. We extended these findings using spatial proteomic analysis of tissue from four surgical resections to examine expression profiles of microglia within their pathological context. Microglia that were spatially aggregated into nodules had increased expression of dynamic immune regulatory markers (PD-L1, CD14, CD11c), T-cell activation markers (CD40, CD80) and were physically located near distinct CD4+ and CD8+ lymphocyte populations. These findings help elucidate the complex immune microenvironment of RE.
2022-12-21 | GSE213364 | GEO