Homo sapiens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA278645 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:The efficiency of central nervous system (CNS) remyelination declines with age. This is in part due to an age-associated decline in the phagocytic removal of myelin debris, which contains inhibitors of oligodendrocyte progenitor cell differentiation. In this study we show that expression of genes involved in the retinoid X receptor (RXR) pathway are decreased with aging in myelin-phagocytosing cells. Loss of RXR function in young macrophages mimics aging by delaying remyelination after experimentally-induced demyelination, while RXR agonists partially restore myelin debris phagocytosis in aged macrophages. The FDA-approved RXR agonist bexarotene, when used in concentrations achievable in human subjects, caused a reversion of the gene expression profile in aging human monocytes to a more youthful profile. These results reveal the RXR pathway as a positive regulator of myelin debris clearance and a key player in the age-related decline in remyelination that may be targeted by available or newly-developed therapeutics. 24 Human CD14+ monocyte-sorted PBMC samples representing 4 Healthy Volunteers (HV) and 4 Multiple Sclerosis (MS) patients under 3 different treatment conditions. Condition 1 = (-) Phagocystosis (-) Bexarotene. Condition 2 = (+) Phagocystosis (-) Bexarotene. Condition 3 = (+) Phagocystosis (+) Bexarotene.
2015-11-04 | E-GEOD-66988 | biostudies-arrayexpress
Project description:The efficiency of central nervous system (CNS) remyelination declines with age. This is in part due to an age-associated decline in the phagocytic removal of myelin debris, which contains inhibitors of oligodendrocyte progenitor cell differentiation. In this study we show that expression of genes involved in the retinoid X receptor (RXR) pathway are decreased with aging in myelin-phagocytosing cells. Loss of RXR function in young macrophages mimics aging by delaying remyelination after experimentally-induced demyelination, while RXR agonists partially restore myelin debris phagocytosis in aged macrophages. The FDA-approved RXR agonist bexarotene, when used in concentrations achievable in human subjects, caused a reversion of the gene expression profile in aging human monocytes to a more youthful profile. These results reveal the RXR pathway as a positive regulator of myelin debris clearance and a key player in the age-related decline in remyelination that may be targeted by available or newly-developed therapeutics.
2015-11-04 | GSE66988 | GEO
Project description:Remyelination is a multistep regenerative process that results in the reformation of myelin sheaths around demyelinated axons and is a critical therapeutic target. Here we show that immediate access to a running wheel following toxin-induced demyelination in mice enhances oligodendrogenesis, myelin thickness, and the proportion of remyelinated axons. RNA-sequencing suggests broad activation of pro-remyelination pathways including phagocytosis by exercise and highlights peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1a) activation. Our study demonstrates that physical activity is an integrative means to enhance remyelination and details a multimodal mechanism including the pivotal PGC1a-dependent enhancement of myelin thickness.
2018-08-16 | GSE118592 | GEO
Project description:Vitamin D deficiency is a major environmental risk factor for the development of multiple sclerosis (MS). The major circulating metabolite of vitamin D (25OHD) is converted to the active form (calcitriol) by the hydroxylase enzyme CYP27B1. In MS lesions the tyrosine kinase MerTK expressed by microglia and macrophages regulates phagocytosis of myelin debris and apoptotic cells that can accumulate and inhibit tissue repair and remyelination. We show that calcitriol downregulates MerTK mRNA and protein expression in primary adult human microglia and monocyte-derived macrophages, thereby inhibiting myelin phagocytosis and apoptotic cell clearance. Proinflammatory myeloid cells express high levels of CYP27B1 compared to homeostatic (TGFb-treated) myeloid cells. Only proinflammatory cells in the presence of TNF-a generate calcitriol from 25OHD, resulting in repression of MerTK expression and function. The selective production of calcitriol in proinflammatory myeloid cells leading to downregulation of MerTK-mediated phagocytosis has the potential to reduce the risk for auto-antigen presentation while retaining the phagocytic ability of homeostatic myeloid cells, thereby contributing to inflammation reduction and enhanced tissue repair.
2020-04-21 | GSE148986 | 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
Project description:After stroke, microglia/blood-derived macrophages, together MF, clear dead cells and cellular debris in the infarcted brain through phagocytosis as an essential part of the repair/recovery process. However, the phagocytic capability of MF declines with age. Furthermore, aged MF become overactivated in response to stroke, enhancing secondary brain injury. Now, demonstrate that by reversing the age-related dysfunctions in MF through activating the retinoid x receptor (RXR), the recovery after stroke in the aged brain could be improved. Using RNA sequencing, we compared the transcriptomes between MF isolated from the brains of young and aged mice. We observed higher levels of pro-inflammatory genes and lower levels of phagocytosis-facilitating genes (Cd206, Cd36) expressed by aged MF. Meanwhile, the treatment with RXR agonist bexarotene (BEX) reversed the signature genes of microglia aging in the aged MF. With the in vivo phagocytosis model, we showed that BEX enhanced the phagocytic ability of aged MF. Using mouse MCAo stroke model, we established that BEX improved sensorimotor and cognitive recovery after MCAo in a myeloid-RXRa-specific and -dependent manner. In conclusion, we showed that activating RXRa partially restores age-related MF dysfunctions and that RXRa deficiency in MF limits the therapeutic effect of RXR in improving post-stroke recovery in the aged brain
2025-09-17 | GSE287142 | GEO
Project description:Remyelination can occur naturally in demyelinating lesions, but often fails in human demyelinating diseases such as multiple sclerosis (MS). The function of the innate immune system is essential for the regenerative response, but how exactly microglia and macrophages clear myelin debris after injury and tailor a specific regenerative response is unclear. Here, we asked whether pro-inflammatory microglial/macrophage activation is required for this process. We established a novel toxin-based spinal cord model of de- and remyelination in zebrafish and showed that pro-inflammatory nuclear factor κB (NF-κB) dependent activation occurs in phagocytes rapidly after myelin injury. We found that the pro-inflammatory response depends on myeloid differentiation primary response 88 (MyD88), the canonical adaptor for inflammatory signaling pathways downstream of toll-like receptors (TLRs). MyD88-deficient mice and zebrafish were impaired not only in the degradation of myelin debris, but also in initiating the generation of new oligodendrocytes for myelin repair. We identified reduced generation of tumor necrosis factor-α (TNF-α) in lesions of MyD88-deficient animals, a pro-inflammatory molecule that was able to induce the generation of new oligodendrocytes. Our study shows that pro-inflammatory phagocytic signaling is an evolutionary conserved mechanism necessary for degrading myelin debris, essential for inflammation resolution, and for initiating the secretion of pro-inflammatory myelin repair molecules.
2020-02-17 | PXD014625 | Pride
Project description:We engineered a novel human iPSC-derived organoid system enriched with mature, myelinating oligodendrocytes and functionally reactive microglia. This model enables the study of human CNS remyelination following a demyelinating insult, encapsulating: myelin fragmentation, microglial clearance of myelin debris and oligodendrocyte genesis, differentiation, and axon ensheathment. This system provides a powerful and unparalleled capacity to interrogate complex human cell behaviour, relevant to those studying glial biology and neurological disease mechanisms.
2025-07-28 | GSE303406 | GEO
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.
2025-08-01 | GSE281947 | GEO
Project description:Microglia are strongly implicated in demyelinating neurodegenerative diseases with increasing evidence for roles in protection and healing, but the mechanisms that control CNS remyelination are poorly understood. Here we show that microglia-specific deletion of TNFR1 and pharmacological inhibition of soluble TNF (solTNF) or downstream IL-1R allow maturation of highly activated disease-associated microglia with increased size and myelin phagocytosis capacity that accelerate cortical remyelination and motor recovery. Single cell transcriptomic analysis of cortex at disease onset reveal that solTNF inhibition enhances reparative IL-10-responsive, while preventing damaging IL-1-related signatures of disease-associated microglia. Longitudinal brain transcriptome analysis through disease reveal earlier recovery upon therapeutic loss of microglia TNFR1. Functional relevance of microglia inflammatory polarization pathways for disease is validated in vivo. Furthermore, disease-state microglia producing downstream IL-1/IL-18/NLRP3/CASP1 targets are identified in human demyelinating lesions. Overall, redirecting disease microglia polarization by targeting cytokines is a potential approach for improving CNS repair in demyelinating disorders.
2024-11-12 | GSE278199 | GEO