Project description:Innate immune memory is a vital mechanism of myeloid cell plasticity that occurs in response to environmental stimuli and alters subsequent immune responses. Two types of immunological imprinting can be distinguished—training and tolerance. These are epigenetically mediated and enhance or suppress subsequent inflammation, respectively. Whether immune memory occurs in tissue-resident macrophages in vivo and how it may affect pathology remains largely unknown. Here we demonstrate that peripherally applied inflammatory stimuli induce acute immune training and tolerance in the brain and lead to differential epigenetic reprogramming of brain-resident macrophages (microglia) that persists for at least six months. Strikingly, in a mouse model of Alzheimer’s pathology, immune training exacerbates cerebral beta-amyloidosis and immune tolerance alleviates it; similarly, peripheral immune stimulation modifies pathological features after stroke. Our results identify immune memory in the brain as an important modifier of neuropathology.
Project description:Innate immune memory is a vital mechanism of myeloid cell plasticity that occurs in response to environmental stimuli and alters subsequent immune responses. Two types of immunological imprinting can be distinguished—training and tolerance. These are epigenetically mediated and enhance or suppress subsequent inflammation, respectively. Whether immune memory occurs in tissue-resident macrophages in vivo and how it may affect pathology remains largely unknown. Here we demonstrate that peripherally applied inflammatory stimuli induce acute immune training and tolerance in the brain and lead to differential epigenetic reprogramming of brain-resident macrophages (microglia) that persists for at least six months. Strikingly, in a mouse model of Alzheimer’s pathology, immune training exacerbates cerebral beta-amyloidosis and immune tolerance alleviates it; similarly, peripheral immune stimulation modifies pathological features after stroke. Our results identify immune memory in the brain as an important modifier of neuropathology.
Project description:Innate immune memory is a vital mechanism of myeloid cell plasticity that occurs in response to environmental stimuli and alters subsequent immune responses. Two types of immunological imprinting can be distinguished-training and tolerance. These are epigenetically mediated and enhance or suppress subsequent inflammation, respectively. Whether immune memory occurs in tissue-resident macrophages in vivo and how it may affect pathology remains largely unknown. Here we demonstrate that peripherally applied inflammatory stimuli induce acute immune training and tolerance in the brain and lead to differential epigenetic reprogramming of brain-resident macrophages (microglia) that persists for at least six months. Strikingly, in a mouse model of Alzheimer's pathology, immune training exacerbates cerebral ?-amyloidosis and immune tolerance alleviates it; similarly, peripheral immune stimulation modifies pathological features after stroke. Our results identify immune memory in the brain as an important modifier of neuropathology.
Project description:Memory CD8+ T cells have the ability to provide lifelong immunity against pathogens. Although memory features generally arise after challenge with a foreign antigen, naïve CD8 single positive (SP) thymocytes may acquire phenotypic and functional characteristics of memory cells in response to cytokines such as interleukin-4. This process is associated with the induction of the T-box transcription factor Eomesodermin (EOMES). However, the underlying molecular mechanisms remain ill-defined. Using epigenomic profiling, we show that these innate memory CD8SP cells acquire only a portion of the active enhancer repertoire of conventional memory cells. This reprograming is secondary to EOMES recruitment, mostly to RUNX3-bound enhancers. Furthermore, EOMES is found within chromatin-associated complexes containing BRG1 and promotes the recruitment of this chromatin remodelling factor. Also, the in vivo acquisition of EOMES-dependent program is BRG1-dependent. In conclusion, our results support a strong epigenetic basis for the EOMES-driven establishment of CD8+ T cell innate memory program.
Project description:Immunological memory is generally thought to be mediated exclusively by lymphocytes such as memory T and B cells. However, enhanced innate immune responses caused by a previous infection increase protection against reinfection suggesting the presence of innate immunological memory. Here, we describe expression profile of peritoneal macrophages from wild-type mice pre-administrated with TLR ligands or from ATF7 knockout mice. ATF7 suppresses a group of innate-immunity genes in macrophage by recruiting H3K9 dimethyltransferase G9a. TLR ligands induce ATF7 phosphorylation, leading to release of ATF7 from chromatin and reduction in H3K9me2 level. Partially disrupted chromatin structure and increased basal expression on target genes are maintained for a long period, increasing resistance pathogens. Therefore we speculate ATF7 is important factor in controlling innate immunological memory. This series contains seven sets of exression array data. For all sample, we use four CEL files generated by four biological-independent experiments.
Project description:Immunological memory is generally thought to be mediated exclusively by lymphocytes such as memory T and B cells. However, enhanced innate immune responses caused by a previous infection increase protection against reinfection suggesting the presence of innate immunological memory. Here, we describe 3,811 ATF7 binding sites in mouse peritoneal macrophages, and 95% of the ATF7 signals in wild-type macrophages are lost in ATF7 knockout macrophages. ATF7 suppresses a group of innate-immunity genes in macrophage by recruiting H3K9 dimethyltransferase G9a. TLR ligands induce ATF7 phosphorylation, leading to release of ATF7 from chromatin and reduction in H3K9me2 level. Partially disrupted chromatin structure and increased basal expression on target genes are maintained for a long period, increasing resistance pathogens. Therefore we speculate ATF7 is important factor in controlling innate immunological memory. This series contains one set of whole genome ChIP-chip data and 2 sets of promoter array ChIP-chip data. For all sample, we use three IP .CEL files and three WCE .CEL files (they are triplicated experiments) to make one profile.
Project description:The pool of memory-phenotype CD8 T cells is composed of antigen-induced (AI) and cytokine-induced innate (IN) cells. Pathogen-induced AI memory cells can be distinguished from naturally-generated IN memory cells by surface expression of NKG2D. AI also differ from IN memory CD8 T cells by their capacity to migrate to the lung parenchyma upon inflammation or infection, a process dependent on their expression of ITGA1/CD49a and ITGA4/CD49d integrins. We used microarrays to identify gene expression signatures that distinguish antigen-induced (AI) from cytokine-induced innate (IN) memory cells.