Project description:Sequencing data related to the manuscript entitled, "CD22 blockade restores homeostatic microglial phagocytosis in the aging brain."
Project description:CD22 (Siglec-2) is a member of the Siglec family. It is an inhibitory co-receptor of the B-cell-receptor (BCR) and inhibits B–cell activation. Upon BCR stimulation ITIMs in the cytoplasmic tail of CD22 are phosphorylated. This triggers CD22 signalling pathways, which lead to a decreased calcium mobilization in the B cell and thus an inhibition of BCR signalling. Although some CD22 binding partners, such as the phosphatase SHP-1, have already been identified, we deciphered the CD22 interactome in more detail, to gain a deeper understanding of CD22 molecular mechanisms and signalling events after BCR activation. Stable isotope labelling of amino acids in cell culture (SILAC) in combination with mass spectrometry analysis enabled the identification of specific CD22 interaction partners in a quantitative proteomics approach. Hereby, several new CD22 associated proteins were identified that have not been linked to CD22 yet. One of those interacting proteins is cullin 3, an E3 ubiquitin ligase. It was revealed that cullin 3 is important for clathrin-dependent CD22 internalization after BCR stimulation and CD22 surface expression. Further analysis of B-cell specific cullin 3 deficient mice showed an important role of cullin 3 in B cell development. These mice have strongly reduced numbers of mature B cells in the periphery, which are characterized by increased CD22 expression and additionally by pre-activated and apoptotic phenotypes.
Project description:Sequencing data related to the manuscript entitled, "CD22 blockade restores homeostatic microglial phagocytosis in the aging brain."
Project description:We report that antibody-mediated CD22 blockage leads to an altered transcriptomic signature profile which, by further evaluating the affected genes, resembles a homeostatic phenotype.
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:Age-dependent alterations in microglia behavior have been implicated in neurodegeneration and CNS injuries. Here, we compared the transcriptional profiles of young versus aged microglia during stroke recovery. CD45intermediateCD11b+ microglia were FACS-isolated from the brains of young (10-week-old) and aged (18-month-old) male mice 14 days after distal middle cerebral artery occlusion (dMCAO) or sham operation and subjected to RNA-sequencing analysis. Functional groups enriched in young microglia are indicative of upregulation in cell movement, cell interactions, inflammatory responses and angiogenesis, while aged microglia exhibited a reduction or no change in these features. We confirmed reduced chemoattractive capacities of aged microglia toward ischemic brain tissue in organotypic slide co-cultures, and delayed accumulation of aged microglia around dead neurons injected into the striatum in vivo. In addition, aging is associated with an overall failure to increase the expression of microglial genes involved in cell-cell interactions, such as CXCL10. Finally, impaired upregulation of pro-angiogenic genes in aged microglia was associated with a decline in neovascularization in aged mice compared to young mice after dMCAO. This study provides a new resource to understand the mechanisms underlying microglial alterations in the aged brain milieu and sheds light on new strategies to improve microglial functions in aged stroke victims.
Project description:Maternal IgG is an immunoglobulin present in breast milk and has been shown to play a role in the development of the immune system in infants. The aim of this study was to investigate the effects of maternal IgG on brain development in mouse pups. Maternal IgG immunoreactivity was observed in microglial cells of the pup brain, peaking at postnatal 8 day. In particular, strong IgG immunoreactivity was observed in the microglia in the corpus callosum and cerebellar white matter. IgG stimulation of primary cultured microglia resulted in activation of the type I interferon feedback loop by Syk. Among the IgG subclasses, IgG2a was found to have a strong influence on microglia. Analysis of FcRn KO mice that were unable to take up IgG from their mothers revealed that these mice had abnormalities in the proliferation and/or survival of microglia, oligodendrocytes, and some types of interneurons. FcRn KO mice also exhibited abnormalities in social behavior and adaptation to novel environments. This study suggests that maternal IgG affects brain development in pups.
Project description:The goal of this study was to determine whether depletion and repopulation of microglia in adult and aged mice reversed age-related immune priming.
Project description:The role of IL-5 in brain neuroimmunity remains unknown. We investigated the role of IL-5 in cognitive function in aged mice. We examined the transcriptomes of sorted microglia and brain T cells from aged mice treated with PBS or IL-5.