Project description:To investigate astrocyte-microglia interactions in vivo, we took advantage of the recombinant rabies virus (RV). We used glycoprotein G-deficient RV expressing the fluorescent protein mCherry and pseudotyped with glycoprotein EnvA, in combination with GFAP-Cre RABVgp4/TVA transgenic mice that express TVA protein and glycoprotein G in astrocytes under the control of the Gfap promoter. Following injection into GfapRABVgp4/TVA mice, RV initially infects TVA expressing astrocytes, and following its replication RV infect cells in direct contact with astrocytes. We then sorted mCherry+ or mCherry- microglia on EAE mice and prove that microglia that had interacted with astrocytes had a more proinflammatory transcriptional profile.
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.
Project description:Isolation of glia from Alzheimer's mice reveals inflammation and dysfunction. Reactive astrocytes and microglia are associated with amyloid plaques in Alzheimer's disease (AD). Yet, not much is known about the molecular alterations underlying this reactive phenotype. To get an insight into the molecular changes underlying AD induced astrocyte and microglia reactivity, we performed a transcriptional analysis on acutely isolated astrocytes and microglia from the cortex of aged controls and APPswe/PS1dE9 AD mice. As expected, both cell types acquired a proinflammatory phenotype, which confirms the validity of our approach. Interestingly, we observed that the immune alteration in astrocytes was relatively more pronounced than in microglia. Concurrently, our data reveal that astrocytes display a reduced expression of neuronal support genes and genes involved in neuronal communication. The microglia showed a reduced expression of phagocytosis and/or endocytosis genes. Co-expression analysis of a human AD expression data set and the astrocyte and microglia data sets revealed that the inflammatory changes in astrocytes were remarkably comparable in mouse and human AD, whereas the microglia changes showed less similarity. Based on these findings we argue that chronically proinflammatory astrocyte and microglia phenotypes, showing a reduction of genes involved in neuronal support and neuronal signaling, are likely to contribute to the neuronal dysfunction and cognitive decline in AD. 2 cell types from 2 conditions: cortical microglia and cortical astrocytes from 15-18 month old APPswe/PS1dE9 mice compared to wildtype littermates. Biological replicates: microglia from APPswe/PS1dE9, N=7, microglia from WT, N=7, astrocytes from APPswe/PS1dE9, N=4, microglia from WT, N=4
Project description:Autoreactive T cells that infiltrate into the central nervous system (CNS) are believed to have a significant role in mediating the pathology of neurodegenerative diseases such as Alzheimer's disease, amyotrophic lateral sclerosis and multiple sclerosis. Their interaction with microglia and astrocytes in the CNS is crucial for the regulation of the neuroinflammatory process. Our previous work demonstrated that effectors secreted by Th1 and Th17 cells have different capacities to influence the phenotype and function of the glial cells. We have shown that Th1 effectors altered the phenotype and function of both microglia and astrocytes whereas Th17 effectors induced direct effects only on astrocytes but not on microglia. Here we investigated if effector molecules associated with IFN-g producing Th1 cells induced different gene expression profiles in microglia and astrocytes. We performed a microarray analysis of RNA isolated from microglia and astrocytes treated with medium and Th1 culture supernatants and compared the gene expression data. By using the criteria of 2-fold change and a false discovery rate of 0.01 (corrected p-value < 0.01), we demonstrated that a total of 2106 and 1594 genes were differentially regulated microglia and astrocytes respectively in response to Th1-derived factors. We observed that Th1 associated effectors induce distinct transcriptional changes in microglia and astrocytes in addition to commonly regulated transcripts. These distinct transcriptional changes regulate distinct physiological functions and this knowledge can help in better understanding of T cell mediated neuropathologies.
Project description:Microglia, brain resident macrophages, require instruction from the central nervous system microenvironment to maintain their identity, morphology, and to regulate inflammatory responses. We investigated the heterogeneity of response of microglia to the presence of neurons and astrocytes by performing single-cell sequencing of microglia in both monoculture, and in coculture with neurons and astrocytes.
Project description:GFAP and vimentin deficiency alters gene expression in astrocytes and microglia in wild-type mice and changes the transcriptional response of reactive glia in mouse model for Alzheimer's disease. Reactive astrocytes with an increased expression of intermediate filament (IF) proteins Glial Fibrillary Acidic Protein (GFAP) and Vimentin (VIM) surround amyloid plaques in Alzheimer's disease (AD). The functional consequences of this upregulation are unclear. To identify molecular pathways coupled to IF regulation in reactive astrocytes, and to study the interaction with microglia, we examined WT and APPswe/PS1dE9 (AD) mice lacking either GFAP, or both VIM and GFAP, and determined the transcriptome of cortical astrocytes and microglia from 15- to 18-month-old mice. Genes involved in lysosomal degradation (including several cathepsins) and in inflammatory response (including Cxcl5, Tlr6, Tnf, Il1b) exhibited a higher AD-induced increase when GFAP, or VIM and GFAP, were absent. The expression of Aqp4 and Gja1 displayed the same pattern. The downregulation of neuronal support genes in astrocytes from AD mice was absent in GFAP/VIM null mice. In contrast, the absence of IFs did not affect the transcriptional alterations induced by AD in microglia, nor was the cortical plaque load altered. Visualizing astrocyte morphology in GFAP-eGFP mice showed no clear structural differences in GFAP/VIM null mice, but did show diminished interaction of astrocyte processes with plaques. Microglial proliferation increased similarly in all AD groups. In conclusion, absence of GFAP, or both GFAP and VIM, alters AD-induced changes in gene expression profile of astrocytes, showing a compensation of the decrease of neuronal support genes and a trend for a slightly higher inflammatory expression profile. However, this has no consequences for the development of plaque load, microglial proliferation, or microglial activation. 2 cell types from 6 conditions: cortical microglia and cortical astrocytes from 15-18 month old APPswe/PS1dE9 mice compared to wildtype littermates. Biological replicates: microglia from APPswe/PS1dE9, N=7, microglia from WT, N=7, astrocytes from APPswe/PS1dE9, N=4, microglia from WT, N=4
Project description:This SuperSeries is composed of the following subset Series: GSE37611: Effect of small molecules on activated astrocytes GSE37612: Effect of small molecules on activated BV2 microglia cell line Refer to individual Series
Project description:Primary lymphoma of the central nervous system (PCNSL) is a diffuse large B cell lymphoma confined to the CNS. In order to elucidate its peculiar organ tropism, we generated recombinant antibodies (recAb) identical with the BCR of a series of 23 PCNSL from immunocompetent patients. While none of the recAb showed self-reactivity upon testing with common autoantigens, they recognized 1547 proteins present on a large-scale protein microarray. Interestingly, proteins recognized by the recAb are physiologically expressed by CNS neurons (GRINL1A, centaurin-α, BAIAP2). Furthermore, 87% (20/23) of the recAb including all antibodies derived from IGHV4 34 using PCNSL recognized galectin-3, which was upregulated on microglia/macrophages, astrocytes, and cerebral endothelial cells upon CNS invasion by PCNSL. Thus, PCNSL Ig may recognize CNS proteins as self-antigens. Their interaction may contribute to BCR signaling with sustained NF-κB activation and, ultimately, may foster tumor cell proliferation and survival. These data may also explain, at least in part, the affinity of the tumor cells of PCNSL to the CNS. Recombinant antibodies (recAb) identical with the BCR of a series of 23 PCNSL from immunocompetent patients.