Brain macrophages adopt distinct profiles prior to demyelination in multiple sclerosis
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ABSTRACT:
PROVIDER: PRJNA743676 | ENA |
REPOSITORIES: ENA
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Project description:Multiple sclerosis is a disease of the central nervous system (CNS) that is characterized by inflammation and focal areas of demyelination, ultimately resulting in axonal degradation and neuronal death. Several lines of evidence point towards a role for microglia and other CNS-associated macrophages in disease initiation and progression, but exactly how lesion formation is triggered is currently unknown. Here, we characterized early changes in MS brains through transcriptomic analysis of normal appearing white matter (NAWM). We found that NAWM was already characterized by expression of inflammatory genes and that expression of genes associated with stress-response was increased, likely as a result of changes in the macrophage compartment. Single cell RNA sequencing analysis confirmed an early stress response in brain macrophages and identified specific macrophage subsets that associate with different stages of demyelinating lesions. These data provide insight into early changes in MS brains that may provide therapeutic targets in order to limit lesion development and demyelination.
2022-02-02 | GSE179427 | GEO
Project description:Intracranial inoculation of the neuroadapted JHM strain of mouse hepatitis virus (JHMV) into susceptible strains of mice results in acute encephalomyelitis and chronic immune-mediated demyelination similar to the human demyelinating disease multiple sclerosis (MS). JHMV infection of transgenic mice in which expression of the neutrophil chemoattractant chemokine CXCL1 is under the control of a tetracycline-inducible promoter active within GFAP-positive cells results in sustained neutrophil infiltration in the central nervous system (CNS) that correlates with an increase in spinal cord demyelination. We used single cell RNA sequencing (scRNAseq) and flow cytometry to characterize molecular and cellular changes within the CNS associated with increased demyelination in transgenic mice compared to control animals. These approaches revealed the presence of activated neutrophils as determined by increased expression of mRNA transcripts associated with increased neutrophil effector functions, such as CD63, MMP9, S100a8, S100a9, and ASPRV1, as well as by altered neutrophil morphology and protein expression. Collectively, these findings reveal insight into changes in the profile of neutrophils associated with increased white matter damage in mice persistently infected with a neurotropic coronavirus.
2022-09-09 | GSE212852 | GEO
Project description:People living with multiple sclerosis (MS) experience episodic central nervous system (CNS) white matter lesions instigated by autoreactive T cells. With age, MS patients show evidence of grey matter demyelination and experience devastating non-remitting symptomology. What drives progression is unclear and has been hampered by the lack of suitable animal models. Here we show that passive experimental autoimmune encephalomyelitis (EAE) induced by an adoptive transfer of young Th17 cells induces a non-remitting clinical phenotype that is associated with persistent leptomeningeal inflammation and cortical pathology in old, but not young SJL/J mice. While the quantity and quality of T cells did not differ in the brains of old vs young EAE mice, an increase in neutrophils and a decrease in B cells was observed in the brains of old mice. Neutrophils were also found in the leptomeninges of a subset of progressive MS patient brains that showed evidence of leptomeningeal inflammation and subpial cortical demyelination. Taken together, our data show that while Th17 cells initiate CNS inflammation, subsequent clinical symptoms and grey matter pathology are dictated by age and associated with other immune cells such as neutrophils.
2022-04-29 | GSE201568 | GEO
Project description:In multiple sclerosis (MS), activated microglia and infiltrating macrophages phagocytose myelin focally in (chronic) active lesions. These demyelinating sites expand in time, but at some point turn inactive into a sclerotic scar. To identify molecular mechanisms underlying lesion activity and halt, we analyzed genome-wide gene expression in rim and peri-lesional regions of chronic active and inactive MS lesions, as well as in control tissue. Gene clustering revealed patterns of gene expression specifically associated with MS and with the presumed, subsequent stages of lesion development. Next to genes involved in immune functions, we found regulation of novel genes in and around the rim of chronic active lesions, such as NPY, KANK4, NCAN, TKTL1, and ANO4. Of note, the presence of many foamy macrophages in active rims was accompanied by a congruent upregulation of genes related to lipid binding, such as MSR1, CD68, CXCL16, and OLR1, and lipid uptake, such as CHIT1, GPNMB, and CCL18. Except CCL18, these genes were already upregulated in regions around active MS lesions, showing that such lesions are indeed expanding. In vitro downregulation of the scavenger receptors MSR1 and CXCL16 reduced myelin uptake. In conclusion, this study provides the gene expression profile of different aspects of MS pathology and indicates that early demyelination, mediated by scavenger receptors, is already present in regions around active MS lesions. Genes involved in early demyelination events in regions surrounding chronic active MS lesions might be promising therapeutic targets to stop lesion expansion.
2018-01-01 | GSE108000 | GEO
Project description:Multiple sclerosis is a chronic inflammatory demyelinating disease of the central nervous system with marked heterogeneity in several aspects including pathological processes. Four histopathological patterns of MS have been described. Pattern II is characterized by infiltrating macrophages and T-cells and by antibody and complement deposition. Transcriptome analysis of three patern II demyelinating brain lesions from a multiple sclerosis patient using RNA sequencing demonstrated the presence of mRNA transcripts for genes specific of activated macrophages, T and B cells as well as genes coding for immunoglobulins, complement proteins and some pattern II associated proteins, providing additional evidence supporting pattern II demyelination. Examination of 3 different demyelinating lesions identified by Immunohistopathology.
2016-07-03 | E-GEOD-60942 | biostudies-arrayexpress
Project description:In the present study we addressed several questions related to the mechanisms of cortical injury. We analyzed genome wide gene expression by microarrays, comparing active multiple sclerosis lesions with highly inflammatory lesions of chronic tuberculous meningitis, with neurodegenerative lesions of Alzheimer’s disease and with normal cortex of age matched controls. To clarify which inflammatory mediators drive demyelination in the human cortex, we characterized and compared the gene expression profile of cortices derived from patients with progressive Multiple Sclerosis (pMS), Meningitis tuberculosis (MT), Alzheimers disease (AD) as well as of normal cortex from age matched controls. 3 cases of each disease were included into the study. Preceding the gene expression profiling all cases were characterized histologically and areas of interest were identified. RNA was isolated from those areas, amplified and hybridized to Agilent G4112F whole genome microarrays.
2011-10-05 | E-GEOD-32645 | biostudies-arrayexpress
Project description:There have been few studies that have focused on the periplaque regions surrounding demyelinated plaques, especially in spinal cords. Areas of incomplete demyelination have been demonstrated but poorly studied. The present study aimed to analyze the molecular immunopathology of periplaque demyelinated lesions (PDLs) in the spinal cord of patients with secondary progressive multiple sclerosis (MS). To achieve this goal, the transcriptomic profiles of PDLs were analyzed in post-mortem tissues derived from the cervical spinal cord of 8 patients with primary or secondary progressive MS. Sixteen spinal cord samples were microdissected for RNA extraction and hybridization on Affymetrix microarrays. Eight periplaque samples (P) were compared to normal appearing white matter (N) from the same patient.
2014-05-30 | E-GEOD-52139 | biostudies-arrayexpress
Project description:Multiple Sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) characterized by demyelination and axonal loss. Demyelinating lesions are associated with infiltrating T lymphocytes, bone marrow-derived macrophages (BMDM), and activated resident microglia. Tissue damage is thought to be mediated by T cell produced cytokines and chemokines, which activate microglia and/or BMDM to both strip myelin and produce toxic factors, ultimately damaging axons and promoting disability. However, the relative contributions of BMDM and microglia to demyelinating pathology are unclear, as their identification in MS tissue is difficult due to similar morphology and indistinguishable surface markers when activated. The CD4 T cell-induced autoimmune murine model of MS, experimental autoimmune encephalitis (EAE), in which BMDM are essential for demyelination, has revealed pathogenic and repair-promoting phenotypes associated with BMDM and microglia, respectively. Using a murine model of demyelination induced by a gliatropic coronavirus, in which BMDM are redundant for demyelination, we herein characterize gene expression profiles of BMDM versus microglia associated with demyelination. While gene expression in CNS infiltrating BMDM was upregulated early following infection and subsequently sustained, microglia expressed a more dynamic gene profile with extensive mRNA upregulation coinciding with peak demyelination after viral control. This delayed microglia response comprised a highly pro-inflammatory and phagocytic profile. Furthermore, while BMDM exhibited a mixed phenotype of M1 and M2 markers, microglia repressed the vast majority of M2-markers. Overall, these data support a pro-inflammatory and pathogenic role of microglia temporally remote from viral control, whereas BMDM retained their gene expression profile independent of the changing environment. As demyelination is caused by multifactorial insults, our results highlight the plasticity of microglia in responding to distinct inflammatory settings, which may be relevant for MS pathogenesis.
2022-10-02 | GSE214472 | GEO
Project description:The failure of multiple sclerosis lesions to resolve in the months after they form leads to smouldering demyelination and axon degeneration (chronic active/slowly expanding lesions). To define mechanisms underlying this disabling, progressive neurodegenerative state, and to foster development of new therapeutics, we used MRI-informed single-nucleus RNA sequencing to profile the edge of demyelinated white matter lesions at various stages of inflammation and compared with healthy control white matter.
2021-09-01 | GSE180759 | GEO
Project description:This study investigated the effect of Vagus Nerve Stimulation (VNS) on innate neuroinflammation and remyelination in lysolecithin (LPC) induced demyelination, a preclinical model for Multiple Sclerosis (MS). In a first experiment (demyelination experiment), LPC was injected in the corpus callosum of 33 Lewis rats, inducing a demyelinated lesion, and rats were treated with either continuously-cycled VNS (cVNS) or one-minute per day VNS (1minVNS) or sham VNS, from two days before the injection until three days post-injection (dpi), when they were killed for immunohistochemistry and proteomics analysis. This timepoint corresponded with a demyelinated lesion and peak inflammation. In a second experiment (remyelination experiment), 13 rats were analogously treated with either cVNS or sham from two days before LPC injection until 11 dpi, when they were killed for tissue prelevation for immunohistochemistry and proteomics. This timepoints corresponded with partial remyelination of the lesion. For proteomics analysis, 20 rats were randomly selected, namely five cVNS and five sham rats of the demyelination experiment, and five cVNS and five sham rats of the remyelination experiment.
2024-05-10 | PXD050858 | Pride