Project description:Murine primary microglia were treated with different inflammatory stimulants to induce different activation states and analyze the associated transcriptional changes. Abstract: Microglia, the immune cells of the CNS, are highly adaptive cells that can acquire different pro- and anti-inflammatory activation states with distinct functions in CNS homeostasis and pathologies. To study microglial function in vitro, primary microglia or immortalized cell lines are commonly used. An alternative to these cells are embryonic stem cell-derived microglia (ESdM). ESdM have previously been shown to be very similar to primary microglia in terms of expression profiles and surface molecules. In this study, ESdM and primary microglia were treated with different inflammatory stimulants to analyze their ability to adopt different activation states. Using quantitative real time PCR, comparative transcriptomics, ELISA, and flow cytometry, we found that different activation states can be induced in ESdM, which are similar to those found in primary microglia. These states are characterized by specific sets of inflammatory marker molecules and differential transcriptome signatures. Our results show that ESdM are a valuable alternative cell model to study microglial functions and neuroinflammatory mechanisms.
Project description:Embryonic stem cell derived microglia (ESdM) were treated with different inflammatory stimulants to analyze their ability to adopt different activation states. Abstract: Microglia, the immune cells of the CNS, are highly adaptive cells that can acquire different pro- and anti-inflammatory activation states with distinct functions in CNS homeostasis and pathologies. To study microglial function in vitro, primary microglia or immortalized cell lines are commonly used. An alternative to these cells are embryonic stem cell-derived microglia (ESdM). ESdM have previously been shown to be very similar to primary microglia in terms of expression profiles and surface molecules. In this study, ESdM and primary microglia were treated with different inflammatory stimulants to analyze their ability to adopt different activation states. Using quantitative real time PCR, comparative transcriptomics, ELISA, and flow cytometry, we found that different activation states can be induced in ESdM, which are similar to those found in primary microglia. These states are characterized by specific sets of inflammatory marker molecules and differential transcriptome signatures. Our results show that ESdM are a valuable alternative cell model to study microglial functions and neuroinflammatory mechanisms.
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:Purpose: We purified whole brain microglia of MFP2 knockout mice and control mice utilizing percoll gradient and FACS sorting, followed by microarray analysis to define the molecular changes in MFP2 knockout mice at the endstage of the disease. We compared the microglia transcriptome of Mfp2-/- microglia to that of SOD1-G93A microglia isolated from spinal cord to define the microglia signature associated with a non-neurodegenerative environment. Results and conclusions: Mfp2-/- microglia acquire an activation state characterized by activation of mammalian target of rapamycin (mTOR). In addition, activated microglia display reduced expression of genes that are normally highly expressed by surveillant microglia in steady-state conditions. The immunological profile of is heterogeneous and encompasses upregulation of both pro- and anti-inflammatory genes. In contrast to the neurodegeneration-specific microglia profile in SOD1-G93A mice, Mfp2-/- microglia do not induce genes associated with phagocytosis, lysosomal activation and neurotoxicity. 4 MFP2 knockout and 4 control samples were subjected to microarray analysis.
Project description:Huntington's Disease (HD) is a fatal neurodegenerative disorder caused by an extended polyglutamine repeat in the N-terminus of the huntingtin (Htt) protein. Reactive microglia and elevated cytokine levels are observed in the brains of HD patients, but the extent to which neuroinflammation results from extrinsic or cell-autonomous mechanisms is unknown. Furthermore, the impact of microglia activation on the pathogenesis of HD remains to be established. Using genome-wide approaches, we show that expression of mutant Htt in microglia promotes cell-autonomous pro-inflammatory transcriptional activation within microglia by increasing the expression and transcriptional activities of the myeloid lineage-determining factors PU.1 and C/EBPs. Elevated levels of PU.1 and its target genes are observed in the brains of mouse models and HD individuals. Moreover, mutant Htt expressing microglia exhibit an increased capacity to induce neuronal death ex vivo and in vivo in the presence of sterile inflammation. These findings suggest that expression of mutant Htt in microglia may contribute to neuronal pathology in Huntingtin disease. RNA-Seq and ChIP-Seq for PU.1, C/EBP, and H3K4me2 in BV2 cells and RNA-Seq in primary microglia and macrophages
Project description:Microglia are key regulators of inflammatory response after stroke and brain injury. Here we profiled the microglia transcriptome isolated from a spontaneously hypertensive rat model of focal cerebral ischemia. We identified an extensive and persistent upregulation of anti-inflammatory M2-like patterns after stroke and a mild up-regulation of pro-inflammatory M1-like patterns at later stage. We also found that younger brains showed larger microglial response than middle aged brains. Moreover, beyond the standard M1/M2 dichotomy, a wide spectrum of novel microglial polarization states was activated in response to stroke, particularly the phenotypes related to Tlr2 and dietary fatty acids stimulation.