Retinoid X Receptor activation reverses the age-related deficiency in myelin debris phagocytosis and enhances remyelination
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE66988 | GEO | 2015/11/04
SECONDARY ACCESSION(S): PRJNA278645
REPOSITORIES: GEO
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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 molecular basis of CNS myelin regeneration (remyelination) is poorly understood. Here we generate a comprehensive transcriptional profile of the separate stages of spontaneous remyelination following focal demyelination in the rat CNS. White matter tracts in the rat caudal cerebellar peduncles were focally demyelinated using 0.1% ethidium bromide, the lesions were isolated using laser capture microdissection at 5, 14 and 28 days postlesion, followed by RNA extraction and Illumina beadarray analysis of differentially expressed transcripts. We found transcripts encoding retinoid acid receptor RXR-gamma is highly differentially expressed during remyelination, and that oligodendrocyte lineage cells express RXR-gamma in rat tissues undergoing remyelination and in active and remyelinated MS lesions. RXR-gamma knockdown by RNA interference or RXR-specific antagonists severely inhibit oligodendrocyte differentiation in culture. In RXR-gamma deficient mice, adult oligodendrocyte precursor cells efficiently repopulate lesions following demyelination, but display delayed differentiation into mature oligodendrocytes. Administration of the RXR agonist 9-cis-retinoic acid to demyelinated cerebellar slice cultures and to aged rats following demyelination results in more remyelinated axons. RXR-gamma is therefore a positive regulator of endogenous oligodendrocyte precursor cell differentiation and remyelination, and may be a pharmacological target for CNS regenerative therapy. 9 Samples analysed, 3 different time points each with 3 biological replicates.
2010-10-22 | E-GEOD-24821 | biostudies-arrayexpress
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:The molecular basis of CNS myelin regeneration (remyelination) is poorly understood. Here we generate a comprehensive transcriptional profile of the separate stages of spontaneous remyelination following focal demyelination in the rat CNS. White matter tracts in the rat caudal cerebellar peduncles were focally demyelinated using 0.1% ethidium bromide, the lesions were isolated using laser capture microdissection at 5, 14 and 28 days postlesion, followed by RNA extraction and Illumina beadarray analysis of differentially expressed transcripts. We found transcripts encoding retinoid acid receptor RXR-gamma is highly differentially expressed during remyelination, and that oligodendrocyte lineage cells express RXR-gamma in rat tissues undergoing remyelination and in active and remyelinated MS lesions. RXR-gamma knockdown by RNA interference or RXR-specific antagonists severely inhibit oligodendrocyte differentiation in culture. In RXR-gamma deficient mice, adult oligodendrocyte precursor cells efficiently repopulate lesions following demyelination, but display delayed differentiation into mature oligodendrocytes. Administration of the RXR agonist 9-cis-retinoic acid to demyelinated cerebellar slice cultures and to aged rats following demyelination results in more remyelinated axons. RXR-gamma is therefore a positive regulator of endogenous oligodendrocyte precursor cell differentiation and remyelination, and may be a pharmacological target for CNS regenerative therapy.
2010-10-22 | GSE24821 | GEO
Project description:Myelin aging is a driving force of CNS aging, and age-dependent declined efficiency of remyelination caused by impaired differentiation capacity of aged oligodendrocyte precursor cell (OPC) is a major cause of demyelinated diseases. Revealing how differentiation capacity of aged OPC is affected metabolically holds the key to find new way to rejuvenate the aged OPC. Here we screened out that NAD+ is one of the top metabolites impaired in premature aging OPC. Supplementing β-nicotinamide mononucleotide (β-NMN), an immediate NAD+ precursor, delays CNS myelin aging, promotes differentiation of aged OPC, and therapeutically and preventively rejuvenates remyelination in the aged CNS both ultra-structurally and functionally. To explore the molecular mechanisms underlying the enhancing remyelination by NAD+ supplementation, using LC-MS we investigated the changes of proteome differentially regulated by NAD+ or DMSO in cultured OPC from P0 rat brain.
2020-10-18 | PXD022046 | iProX
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:Retinoid X Receptor activation reverses the age-related deficiency in myelin debris phagocytosis and enhances remyelination
| PRJNA278645 | ENA
Project description:The human placenta is covered by a single multinucleated fetal cell, the syncytiotrophoblast, which is bathed in maternal blood. During all pregnancies, membrane enclosed extracellular vesicles derived from the syncytiotrophoblast are extruded into the maternal blood.The large size of these extracellular vesicles (diameter larger than 10µm) is referred to as trophoblastic debris in this study. We have shown in the past that endothleial cells are involved in clearence of this trophoblastic debris and induction of immune tolerence by trophoblastic debris.This study aimed to characterise the transcriptional changes that occur in human vascular endothelial cells following exposure to trophoblastic debris from normal first trimester placentae. Microarrays were used to probe transcriptomic changes 2 and 21 hours after exposure of endothelial cells (Human microvascular endothelial cell line,HMEC-1) to trophoblastic debris from normal first trimester placentae Trophoblastic debris were isolated by low speed centrifugation from three individual first trimester human placentae (three biological replicates). The protein content in trophoblastic debris was measured by BCA assay. HMEC-1 was co-cultured with trophoblastic debris (60ug/ml total debris protein contents) for either 2 or 21 hours before RNA extraction. Untreated HMEC-1 at 2 and 21 hours were used as controls.In total, 12 samples were analyzed.
2016-08-21 | E-GEOD-69996 | biostudies-arrayexpress
Project description:The liver X receptors (LXRs) are nuclear receptors that form permissive heterodimers with retinoid X receptor (RXR) and are important regulators of lipid metabolism in the liver. We have recently shown that RXR agonist-induced hypertriglyceridemia and hepatic steatosis in mice is dependent on LXR and correlates with an LXR-dependent hepatic induction of lipogenic genes. To further investigate the role of RXR and LXR in the regulation of hepatic gene expression, we have mapped the ligand-regulated genome-wide binding of these factors in mouse liver. We find that the RXR agonist bexarotene primarily increases the genomic binding of RXR, whereas the LXR agonist T0901317 greatly increases both LXR and RXR binding. Functional annotation of putative direct LXR target genes revealed a significant association with classical LXR-regulated pathways as well as PPAR signaling pathways, and subsequent ChIP-seq mapping of PPARM-NM-1 binding demonstrated binding of PPARM-NM-1 to 71-88% of the identified LXR:RXR binding sites. Sequence analysis of shared binding regions combined with sequential ChIP on selected sites indicate that LXR:RXR and PPARM-NM-1:RXR bind to degenerate response elements in a mutually exclusive manner. Together our findings suggest extensive and unexpected cross-talk between hepatic LXR and PPARM-NM-1 at the level of binding to shared genomic sites LXR, RXR, PPARalpha and RNA Polymerase II ChIP-seq on livers from female C57BL/6 wild-type and/or LXRM-NM-1/M-NM-2-deficient mice (13 weeks of age, n=1) treated by oral gavage once daily for 14 days with the RXR agonist bexarotene (100 mg/kg body weight [mpk], in 1% carboxymethylcellulose), the LXR agonist T0901317 (T09, 30 mpk) or vehicle alone.
2012-01-31 | E-GEOD-35262 | biostudies-arrayexpress
Project description:The human placenta is covered by a single multinucleated fetal cell, the syncytiotrophoblast, which is bathed in maternal blood. During all pregnancies, membrane enclosed extracellular vesicles derived from the syncytiotrophoblast are extruded into the maternal blood.The large size of these extracellular vesicles (diameter larger than 10µm) is referred to as trophoblastic debris in this study. We have shown in the past that endothleial cells are involved in clearence of this trophoblastic debris and induction of immune tolerence by trophoblastic debris.This study aimed to characterise the transcriptional changes that occur in human vascular endothelial cells following exposure to trophoblastic debris from normal first trimester placentae. Microarrays were used to probe transcriptomic changes 2 and 21 hours after exposure of endothelial cells (Human microvascular endothelial cell line,HMEC-1) to trophoblastic debris from normal first trimester placentae
2016-08-21 | GSE69996 | GEO