CD8+ T cells induce interferon-responsive oligodendrocytes during white matter aging
Ontology highlight
ABSTRACT: A hallmark of nervous system aging is a decline of white matter volume and function, but the underlying mechanisms leading to white matter pathology are unknown. Here, we found age-related alterations of oligodendrocytes with a reduction of total oligodendrocyte density in the aging murine white matter. Using single-cell RNA sequencing, we identify interferon-responsive oligodendrocytes, which localize in proximity of CD8+ T cells in the aging white matter. Absence of functional lymphocytes decreased oligodendrocyte reactivity and rescued oligodendrocyte loss, while T-cell checkpoint inhibition worsened the aging effect. In addition, we identified a subpopulation of immune cell dependent interferon-responsive microglia in the aging white matter, and co-culture experiments revealed that interferon- activated microglia triggered oligodendrocytes cell death. In summary, we provide evidence that T cells induced interferon-responsive oligodendrocytes and microglia are important modifiers of white matter aging.
Project description:Increasing evidence indicates heterogeneity in functional and molecular properties of oligodendrocyte lineage cells both during development and under pathologic conditions. In multiple sclerosis, remyelination of grey matter lesions exceeds that in white matter. Here we used cells derived from grey matter versus white matter regions of surgically resected human brain tissue samples, to compare the capacities of human A2B5-positive progenitor cells and mature oligodendrocytes to ensheath synthetic nanofibers, and relate differences to the molecular profiles of these cells. For both cell types, the percentage of ensheathing cells was greater for grey matter versus white matter cells. For both grey matter and white matter samples, the percentage of cells ensheathing nanofibers was greater for A2B5-positive cells versus mature oligodendrocytes. Grey matter A2B5-positive cells were more susceptible than white matter A2B5-positive cells to injury induced by metabolic insults. Bulk RNA sequencing indicated that separation by cell type (A2B5-positive vs mature oligodendrocytes) is more significant than by region but segregation for each cell type by region is apparent. Molecular features of grey matter versus white matter derived A2B5-positive and mature oligodendrocytes were lower expression of mature oligodendrocyte genes and increased expression of early oligodendrocyte lineage genes. Genes and pathways with increased expression in grey matter derived cells with relevance for myelination included those related to responses to external environment, cell-cell communication, cell migration, and cell adhesion. Immune and cell death related genes were up-regulated in grey matter derived cells. We observed a significant number of up-regulated genes shared between the stress/injury and myelination processes, providing a basis for these features. In contrast to oligodendrocyte lineage cells, no functional or molecular heterogeneity was detected in microglia maintained in vitro, likely reflecting the plasticity of these cells ex vivo. The combined functional and molecular data indicate that grey matter human oligodendrocytes have increased intrinsic capacity to myelinate but also increased injury susceptibility, in part reflecting their being at a stage earlier in the oligodendrocyte lineage.
Project description:Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is a neurodegenerative disorder resulting from genetic alterations in CSF1R, a gene expressed by microglia. We studied an elderly man with a hereditary progressive dementing and behavioral disorder of unclear etiology. Standard genetic testing for leukodystrophy and other neurodegenerative conditions was negative. Brain autopsy revealed classic features of ALSP, including confluent white matter degeneration with axonal spheroids and pigmented glial cells in the affected white matter. Subsequent long-read sequencing identified a novel deletion in CSF1R. To elucidate mechanisms underlying white matter degeneration in ALSP, we compared multiple brain regions exhibiting varying degrees of white matter pathology. Our analysis revealed markedly decreased CSF1R transcript levels and protein across brain regions, including intact white matter. Single nuclear RNA sequencing (snRNAseq) analysis identified two disease-associated microglial cell states: lipid-laden microglia (expressing GPNMB, ATG7, LGALS1, LGALS3) and inflammatory microglia (expressing IL2RA, ATP2C1, FCGBP, VSIR, SESN3), along with a small population of CD44+ peripheral monocyte-derived macrophages exhibiting migratory and phagocytic signatures. Disease-associated oligodendrocytes exhibited cell stress signatures and dysregulated apoptosis-related genes. Disease-associated oligodendrocyte precursor cells (OPCs) displayed a failure in their differentiation into mature myelin-forming oligodendrocytes, as evidenced by upregulated LRP1, PDGFRA, SOX5, NFIA, and downregulated NKX2-2, NKX6.2, SOX4, SOX8, TCF7L2, YY1, ZNF488. Overall, our findings highlight microglia–oligodendroglia crosstalk in demyelination, with CSF1R dysfunction promoting phagocytic and inflammatory microglia states, resulting in oligodendrocyte depletion, an arrest in OPC differentiation, and lack of remyelination.
Project description:Aging results in both grey and white matter degeneration, but the specific microglial responses are unknown. Using single-cell RNA sequencing from white and grey matter separately, we identified white matter associated microglia (WAM), which share parts of the disease-associated microglia (DAM) gene signature and are characterized by the activation of genes implicated in phagocytic activity and lipid metabolism. WAM depend on triggering receptor expressed on myeloid cells 2 (TREM2) signaling and are aging dependent. In the aged brain, WAM form independently of apolipoprotein E (APOE), which is in contrast to mouse models of Alzheimer’s disease, in which microglia with WAM gene signature are generated prematurely and in an APOE-dependent pathway similar to DAM. Within the white matter, microglia frequently cluster in nodules, where they are engaged in clearing degenerated myelin. Thus, WAM may represent a potentially protective response required to clear degenerated myelin accumulating during white matter aging and disease.
Project description:Recently we demonstrated that amoeboid microglia in white matter regions are essential for proper oligodendrocyte homeostasis and myelinogenesis in the first postnatal week of mice. Amoeboid microglia in the corpus callosum change their activation profile already within few days after postnatal day (P)7 and microglia of the cerebellum show similar features to callosal microglia. Here we expanded our previous transcriptional analysis and performed bulk RNA sequencing of microglia during development in a detailed way in P7, P10 and P42 microglia from corpus callosum, cortex and cerebellum. The goal of this study was to identify a specific gene profile for both, white matter and grey matter microglia during development.
Project description:Aging is the major risk factor for neurodegeneration and associated with structural and functional alterations in white matter. Myelin is particularly vulnerable to aging resulting in white matter-associated microglia activation. In this study, we employed pharmacological and genetic approaches to investigate microglial functions related to aging-associated changes in myelinated axons of mice. Our results reveal that maladaptive microglia activation promotes the accumulation of CD8+ T cells, leading to degeneration of myelinated axons and subsequent impairment of brain function and behavior. We characterize glial heterogeneity and aging-related changes in white matter by single-cell and spatial transcriptomics and reveal elaborate glial-immune interactions. Mechanistically, we show that the CXCL10-CXCR3 axis is crucial for the recruitment and retention of CD8+ T cells in aged white matter, where they exert pathogenic effects. Our results indicate that myelin-related microglia dysfunction promotes adaptive immune reactions in aging and identify putative targets to mitigate their detrimental impact.
Project description:Aging is the major risk factor for neurodegeneration and associated with structural and functional alterations in white matter. Myelin is particularly vulnerable to aging resulting in white matter-associated microglia activation. In this study, we employed pharmacological and genetic approaches to investigate microglial functions related to aging-associated changes in myelinated axons of mice. Our results reveal that maladaptive microglia activation promotes the accumulation of CD8+ T cells, leading to degeneration of myelinated axons and subsequent impairment of brain function and behavior. We characterize glial heterogeneity and aging-related changes in white matter by single-cell and spatial transcriptomics and reveal elaborate glial-immune interactions. Mechanistically, we show that the CXCL10-CXCR3 axis is crucial for the recruitment and retention of CD8+ T cells in aged white matter, where they exert pathogenic effects. Our results indicate that myelin-related microglia dysfunction promotes adaptive immune reactions in aging and identify putative targets to mitigate their detrimental impact.
Project description:Label-free global proteomic analysis of progressive multiple sclerosis (P-MS) and control (ODC) brain tissue (cortex/CTX, normal appearing white matter/NAWM, white matter lesions/WML), primary human neural cell types (neurons, microglia, astrocytes, oligodendrocyte progenitor cells), and CNS tissue (brain, spinal cord) from mouse models of MS (EAE and cuprizone).
Project description:Although the underlying neurobiology of major mental illness (MMI) remains unknown, emerging evidence implicates a role for oligodendrocyte-myelin abnormalities. Here, we took advantage of a large family carrying a balanced t(1;11) translocation, which substantially increases risk of MMI, to undertake both diffusion tensor imaging (DTI) and cellular studies to evaluate the consequences of the t(1;11) translocation on white matter structural integrity and oligodendrocyte-myelin biology (this translocation disrupts among others the DISC1 gene which plays a crucial role in brain development). At a cellular level, we observe dysregulation of key pathways controlling oligodendrocyte development and morphogenesis in induced pluripotent stem cell (iPSC) case derived oligodendrocytes.
Project description:Which proteins in oligodendrocytes require VAMP2/3-mediated exocytosis for membrane trafficking? We isolated primary oligodendrocytes from transgenic mice expressing oligodendrocyte-targeted botulinum toxin and littermate controls and used surface biotinylation to determine which proteins were differentially trafficked to the cell surface.