Transcriptome analysis of myeloid cells (CD11b) and astrocytes (ACSA2) from the striatum and midbrain of control and parkinsonian animals
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ABSTRACT: Inflammation is a common feature in neurodegenerative diseases that participates in the process of neuronal loss. Here, we questioned whether the inflammatory reaction generated in Parkinson´s disease (PD) by dopaminergic neuron degeneration would trigger specific inflammatory reactions in the midbrain and in the striatum that could modify the course of neuronal death. Experimental parkinsonism was induced by overexpressing α-synuclein in the substantia nigra with a viral vector. Bulk RNA sequencing of purified midbrain microglia/myeloid cells showed a phagocytic and anti-inflammatory M2 phenotype, while midbrain astrocytes presented a pro-inflammatory state. In the striatum, microglia but not astrocytes presented a pro-inflammatory state.
Project description:Neuroinflammation is a common hallmark of neurodegenerative diseases such as Parkinson’s disease (PD). Here, we questioned about the activation state of glial cells along the degeneration process of dopaminergic terminals in the striatum and loss of neuronal cell bodies in the midbrain. We hypothesized that MPTP administration pattern would produce different inflammatory responses that could modify the course of nigrostriatal degeneration. To reproduce the dopaminergic impairment in a PD experimental mouse model, we used two different MPTP-administration patterns: subacute (sMPTP) and chronic (cMPTP). Bulk RNA sequencing of purified midbrain microglia/myeloid cells of sMPTP mice showed an anti-inflammatory phenotype, while midbrain microglia/myeloid cells of cMPTP mice showed a pro-inflammatory and phagocytic phenotype. Midbrain astrocytes presented a phagocytic phenotype in sMPTP mice. In the striatum, microglia presented a continuous pro-inflammatory state in sMPTP and cMPTP conditions. In this region, astrocytes presented a remarkable activated and phagocytic state in sMPTP mice which was attenuated with the chronicity of MPTP administration.
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:Aggressive inflammation and excessive scar formation are the main cause to the difficulty of neural tissue repair after spinal cord injury (SCI). Microglia and astrocytes act as important role in this micro-environment of SCI and there is cross regulation between microglia and astrocytes. After SCI, MG0 polarized into MG1 and MG3 which were belong to pro-inflammatory phenotype microglia; Naive astrocytes polarized into Reactive and Scar-forming astrocytes. Growth arrest-specific 6 (Gas6) and its receptor Axl was declined in all these cells after SCI. In vitro study, Gas6 had the negative effect on cytotoxic astrocytes and pro-inflammatory microglia polarization and even the cross regulation between cytotoxic astrocytes and pro-inflammatory microglia. Further mechanism study indicated that Gas6 suppressed cytotoxic phenotype polarization of astrocytes through inhibited the activation of YES-associated protein (YAP) signal pathway and suppressed pro-inflammatory phenotype polarization of microglia through inhibited the activation of NF-κB/p65 and JAK/Stat3 signal pathways. In vivo study, Gas6 treatment suppressed cytotoxic astrocytes and pro-inflammatory microglia polarization at the injured site of spinal cord to facilitate tissue repair and loco-motor recovery.
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:Microglia constitutes a diverse population of cells that present a broad spectrum of responses when they become activated. Here, microglial status was studied under steady-state conditions from different brain regions involved in neurodegenerative diseases. Under basal conditions, midbrain microglia showed an immune-alert state not observed in striatum. Unique subpopulations of microglia expressing TLR4 and MHC-II with antigen presenting properties, and a higher proportion of infiltrating CD4+ T cells were identified in the midbrain. These results highlight that the inflammatory tone is context-dependent and reveal the unique properties of the midbrain related to the interaction with the immune system.
Project description:We report XBP1 activation and regulation of pro-inflammatory signaling in astrocytes, microglia, and CNS-recruited pro-inflammatory monocytes during EAE.
Project description:Preparation of primary microglial cultures from postnatal mice is tedious with a low yield, high variability and risk of astrocytic contamination. Microglia derived from embryonic stem cells (ESdM) have been suggested as alternative source, but it is unclear how closely ESdM resemble the molecular phenotype of primary microglia. Here, we performed a whole transcriptome analysis of ESdM in comparison to primary cultured and flow cytometry-sorted microglia and compared the microglial transcriptome to other cell types. Cultured microglia and ESdM were related to sorted microglia, but clearly distinct from other myeloid cell types, T cells, astrocytes and neurons. ESdM and primary cultured microglia showed strong overlap in their transcriptome. Only 144 gene transcripts were differentially expressed between both cell types, mainly derived from immune-related genes with a higher activation status of pro-inflammatory and immune defense genes in primary microglia compared to ESdM. Flow cytometry analysis of cell surface markers CD54, CD74 and CD274 selected from the microarray confirmed the close phenotypic relation between ESdM and primary cultured microglia. Thus, assessment of genome-wide transcriptional regulation demonstrates that microglia are distinct from other macrophage cell types and that mouse pluripotent stem cell-derived microglia are closely related to cultured postnatal microglia. Comparison of different primary neuronal cells with ES-cell derived microglial cells
Project description:Background: Widescale evidence points to the involvement of glia and immune pathways in the progression of Alzheimer’s disease (AD). AD-associated iPSC-derived glial cells show a diverse range of AD-related phenotypic states encompassing cytokine/chemokine release, phagocytosis and morphological profiles, but to date studies are limited to cells derived from PSEN1, APOE and APP mutations or sporadic patients. The aim of the current study was to successfully differentiate iPSC-derived microglia and astrocytes from patients harbouring an AD-causative PSEN2 (N141I) mutation and characterise the inflammatory and morphological profile of these cells. Methods: iPSCs from three healthy control individuals and three familial AD patients harbouring a heterozygous PSEN2 (N141I) mutation were used to derive astrocytes and microglia-like cells and cell identity and morphology were characterised through immunofluorescent microscopy. Cellular characterisation involved the stimulation of these cells by LPS and Aβ42 and analysis of cytokine/chemokine release was conducted through ELISAs and multi-cytokine arrays. The phagocytic capacity of these cells was then indexed by the uptake of fluorescently labelled fibrillar Aβ42. Results: AD-derived astrocytes and microglia-like cells exhibited an atrophied and less complex morphological appearance than healthy controls. AD-derived astrocytes showed increased basal expression of GFAP, S100β and increased secretion and phagocytosis of Aβ42 while AD-derived microglia-like cells showed decreased IL-8 secretion compared to healthy controls. Upon immunological challenge AD-derived astrocytes and microglia-like cells show exaggerated secretion of the pro-inflammatory IL-6, CXCL1, ICAM-1 and IL-8 from astrocytes and IL-18 and MIF from microglia.Conclusion: Our study showed, for the first time, the differentiation and characterisation of iPSC-derived astrocytes and microglia-like cells harbouring a PSEN2 (N141I) mutation. PSEN2 (N141I)-mutant astrocytes and microglia-like cells presented with a ‘primed’ phenotype characterised by reduced morphological complexity, exaggerated pro-inflammatory cytokine secretion and altered Aβ42 production and phagocytosis.
Project description:To determine the role of RIPK1 kinase-dependent transcriptional signaling in microglia and astrocytes, we stimulated cells with RIPK1 kinase-activating stimuli TNF/5z-7 and TNF/Smac/zVAD in the presence or absence of the RIPK1 kinase inhibitor Nec-1s. We identified various genes modulated in a RIPK1 kinase-dependent manner with each stimulation in both microglia and astrocytes, and the main biological pathways were related to an inflammatory and immune response. We identified many cytokines and chemokines upregulated in both microglia and astrocytes upon RIPK1 kinase activation, demonstrating the contribution of RIPK1 kinase signaling to pro-inflammatory responses in microglia and astrocytes
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.