Age-impaired remyelination is associated with dysregulated microglial transitions.
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ABSTRACT:
PROVIDER: PRJNA1186235 | ENA |
REPOSITORIES: ENA
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Project description:Multiple sclerosis (MS) is a chronic, inflammatory condition characterized by demyelination and neurodegeneration. Regeneration of lost myelin, or remyelination, occurs in people with MS but is prone to failure and impaired with age. Remyelination is facilitated by microglia but our understanding of the microglial response during remyelination is incomplete. Here, we profiled the microglial response in the lysolecithin mouse model of remyelination using single-cell RNA sequencing. We found several distinct microglial states during the early stages of remyelination that coalesced into a resolved microglial state defined by myelin transcripts. This resolved state was also present in MS brains. As remyelination becomes inefficient with age, we profiled microglia from both young and middle-aged mice during remyelination and found a delay in several microglial states, in concordance with delayed remyelination. Overall, microglia synchronously initiate a multi-faceted response during efficient remyelination in young mice, which becomes dysregulated with age.
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Project description:Aging accelerates central nervous system remyelination failure and neurodegeneration. Microglia promote remyelination by phagocytosing myelin debris, but this function is impaired by aging-related CD22 upregulation. However, the molecular mechanisms counteracting premature aging-related microglial dysfunction and remyelination impairment remain unclear. Here, we report that Aurka-Bhlhe41 axis prevents premature aging-like microglial dysfunction and promotes remyelination by restraining progressive CD22 upregulation. We identified that microglia-enriched Bhlhe41 was negatively autoregulated and inhibited by Aurka loss. Bhlhe41- or Aurka-deficient young mice exhibited aging-like microglial morphology, phagocytic deficits, progressive CD22 upregulation, and remyelination impairment in cuprizone-induced demyelination model. Conversely, ectopic Bhlhe41 expression induced hypertrophic microglia, and counteracted phagocytic deficits and CD22 upregulation in Aurka-deficient microglia. CD22 blockade restored phagocytic function and remyelination in Bhlhe41-deficient mice. Notably, a conserved pattern of CD22 upregulation was observed in human PCDH9high microglia subsets with BHLHE41 downregulation. These findings offer insights into potential therapeutic strategies to combat aging-related neurodegeneration and central nervous system functional decline.
2026-02-18 | GSE276929 | GEO
Project description:We employed a cuprizone-induced demyelinating model to identify the role of AhR in remyelination with microglial AhR-deficient mice and wild type mice. RNA-seq was performed to compare gene transcriptional profile in wild type mice and microglial AhR-deficient mice of cuprizone model to gain insight into the effects of AhR on microglia function.
2022-08-03 | GSE210147 | GEO
Project description:Microglia, the resident immune cells of the central nervous system (CNS), are important regulators of normal brain activities. In CNS demyelinating diseases like multiple sclerosis (MS), the functions of these cells are of particular interest. Based on the observation of diminished Dicer positive microglia/macrophages number in demyelinating white matter lesions (WMLs) of human MS brains, here we probed the impact of impaired microRNA (miRNA)-mediated post-transcriptional gene regulation in a mouse model lacking microglia/macrophage-specific Dicer1 expression during demyelination and remyelination. Conditional Dicer1 ablation and loss of miRNAs expression in adult microglia led to extensive demyelination and impaired myelin processing. Interestingly, demyelination was accompanied by increased apoptosis of mature oligodendrocytes (OLs) and arresting oligodendrocyte progenitor cells (OPCs) in the precursor stage. At the transcriptional level, Dicer1-deficient microglia led to downregulation of microglial homeostatic genes, increased cell proliferation, and a shift towards a disease-associated phenotype. Loss of remyelination efficiency in these mice was accompanied by stalling of OPCs in the precursor stage. Collectively, finding from this study highlight a new role of microglial miRNAs in promoting a pro-regenerative phenotype in addition to promoting OPC maturation and differentiation during demyelination and remyelination.
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Project description:Aurka-Bhlhe41 axis prevents premature aging-like microglial dysfunction and promotes remyelination
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Project description:New research shows that disease-associated microglia (DAM) in neurodegenerative brains present features of elevated phagocytosis, lysosomal functions, and lipid metabolism, which benefit brain repair. The underlying mechanisms remain poorly understood. Intracellular pHi is important for regulating aerobic glycolysis in microglia, where Na/H exchanger (NHE1) is a key pH regulator by extruding H+ in exchange of Na+ influx. We report here that post-stroke Cx3cr1-CreER+/-;Nhe1flox/flox (Nhe1 cKO) brains displayed stimulation of microglial transcriptomes of rate-limiting enzyme genes for glycolysis, tricarboxylic acid cycle, and oxidative phosphorylation (OXPHOS). The other upregulated genes included the DAM hallmark genes (Apoe, Trem2, Spp1) as well as genes for phagocytosis and LXR/RXR pathway activation. The cKO microglia exhibited increased OXPHOS capacity and higher phagocytic activity, which led to enhanced synaptic pruning, oligodendrogenesis, and remyelination. This study reveals that genetic blockade of microglial NHE1 stimulated glucose immunometabolism to support phagocytosis function for tissue remodeling and post-stroke cognitive function recovery.
2022-01-28 | GSE175504 | GEO
Project description:Here we used single cell RNA-sequencing and single cell spatial transcriptomics to characterize the forebrain neural stem cell (NSC) niche under homeostatic and injury conditions. We define the dorsal and lateral ventricular-subventricular zones (V-SVZ) as two distinct neighborhoods, and show that following white matter injury, dorsal NSCs are locally activated to make oligodendrocytes for remyelination. This activation is coincident with a robust increase in transcriptionally-distinct microglia in the dorsal V-SVZ niche. We modeled ligand-receptor interactions within this changing niche and identified two remyelination-associated microglial ligands, IGF1 and OSM, that promote precursor proliferation and oligodendrogenesis in culture. Infusion of either ligand into the lateral ventricles also enhanced oligodendrogenesis, even in the lateral V-SVZ, where NSCs normally make neuroblasts. These data support a model where gliogenesis versus neurogenesis is determined by the local NSC neighborhood and where injury-induced niche alterations promote NSC activation, local oligodendrogenesis, and likely contribute to myelin repair.
2024-12-20 | GSE266688 | GEO
Project description:Here we used single cell RNA-sequencing and single cell spatial transcriptomics to characterize the forebrain neural stem cell (NSC) niche under homeostatic and injury conditions. We define the dorsal and lateral ventricular-subventricular zones (V-SVZ) as two distinct neighborhoods, and show that following white matter injury, dorsal NSCs are locally activated to make oligodendrocytes for remyelination. This activation is coincident with a robust increase in transcriptionally-distinct microglia in the dorsal V-SVZ niche. We modeled ligand-receptor interactions within this changing niche and identified two remyelination-associated microglial ligands, IGF1 and OSM, that promote precursor proliferation and oligodendrogenesis in culture. Infusion of either ligand into the lateral ventricles also enhanced oligodendrogenesis, even in the lateral V-SVZ, where NSCs normally make neuroblasts. These data support a model where gliogenesis versus neurogenesis is determined by the local NSC neighborhood and where injury-induced niche alterations promote NSC activation, local oligodendrogenesis, and likely contribute to myelin repair.
2024-12-20 | GSE266689 | GEO
Project description:Microglia are considered both pathogenic and protective during recovery from demyelination, but their precise role remains ill-defined. Here, using an inhibitor of colony stimulating factor 1 receptor (CSF1R), PLX5622, and mice infected with a neurotropic coronavirus (mouse hepatitis virus, strain JHMV), we show that depletion of microglia after clearance of virus infection resulted in impaired myelin repair and prolonged clinical disease. Microglia were required only during the early stages of remyelination. Notably, large deposits of extracellular vesiculated myelin and cellular debris were detected in the spinal cords of PLX5622-treated and not control mice, which correlated with decreased numbers of oligodendrocytes in demyelinating lesions in drug-treated mice. Further, gene expression analyses demonstrated differential expression of genes involved in myelin debris clearance, lipid and cholesterol recycling, and promotion of oligodendrocyte function. The results also demonstrate that microglial function could not be compensated by infiltrating macrophages. Together, these results demonstrate key roles for microglia in debris clearance and the initiation of remyelination following infection with a neurotropic coronavirus but are not necessary during later stages of remyelination.
2020-02-07 | GSE144911 | GEO