Project description:We inflicted TBI to chemokine-deficient mouse lines in order to establish involvement of various signalling pathways that may be addressed therapeutically. Interacting chemokine pathways in brain regulate distinct inflammatory cells. Activated microglia are separate from invading phagocytes and dendritic cells. Findings show potential targets to interfere with specific inflammatory responses after brain injury.
Project description:We inflicted TBI to chemokine-deficient mouse lines in order to establish involvement of various signalling pathways that may be addressed therapeutically. Interacting chemokine pathways in brain regulate distinct inflammatory cells. Activated microglia are separate from invading phagocytes and dendritic cells. Findings show potential targets to interfere with specific inflammatory responses after brain injury. TBI was carried out in Ccl3-/- and Ccr2-/- mice, total RNA prepared from injured cerebral neocortex after three days. RNA samples were from uninjured Ccl3-/- and Ccr2-/- mice as reference for hybridization on Affymetrix microarrays.
Project description:We inflicted TBI to wildetype (wt) mice in order to establish whether the anti-inflammatory agent cyclophosphamide can be used therapeutically. Cyclophosphamide was found to regulate distinct inflammatory cells such as activated microglia separate from invading phagocytes and dendritic cells. Cyclophosphamide postinjury selectively reduces antigen-presenting dendritic cells. Findings show feasibility of drug development to interfere with brain inflammation.
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.
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
Project description:We use microarray analysis to compare the expression profiles of glioma-associated microglia/macrophages and naive control cells. Samples were generated from CD11b+ MACS-isolated cells from naïve and GL261-implanted C57BL/6 mouse brains.
Project description:We inflicted TBI to wildetype (wt) mice in order to establish whether the anti-inflammatory agent cyclophosphamide can be used therapeutically. Cyclophosphamide was found to regulate distinct inflammatory cells such as activated microglia separate from invading phagocytes and dendritic cells. Cyclophosphamide postinjury selectively reduces antigen-presenting dendritic cells. Findings show feasibility of drug development to interfere with brain inflammation. TBI was carried out in injured wt B6 mice for postinjury treatment with cyclophospamide i.p. using saline as a control substance for comparison with injured but untreated mice. Total RNA was prepared from injured cerebral neocortex after three days. RNA samples were also from uninjured wt mice as reference for hybridization on Affymetrix microarrays.
Project description:ATAC-seq profiling of Nfat5 KO and wild type macrophages derived from bone marrow (primary cells), treated or not with Lipopolysaccharide (LPS).
Project description:Microglia, brain-resident macrophages, have been proposed to play an active role in synaptic refinement and maturation, influencing plasticity and circuit-level connectivity. Using a genetically modified mouse which lacks microglia (Csf1r ∆FIRE/∆FIRE), we investigate the effect on gene expression of the presence or absence of microglia in the developing mouse brain.