Fibroblast growth factor 9 inhibits remyelination via an off target effect on astrocytes in multiple sclerosis
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ABSTRACT:
ORGANISM(S): Rattus norvegicus
PROVIDER: GSE44562 | GEO | 2016/02/17
SECONDARY ACCESSION(S): PRJNA190060
REPOSITORIES: GEO
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Project description:Failure of remyelination in multiple sclerosis (MS) is associated with inhibition of oligodendrocyte precursor (OPC) differentiation, but the cellular and molecular mechanisms involved remain poorly understood. We now report inflammatory demyelination in MS is associated with localized expression of fibroblast growth factor 9 (FGF9) by oligodendrocytes and to a lesser extent astrocytes, and demonstrate FGF9 inhibits myelination and remyelination in vitro. This inhibitory activity is reversible and due to an off target FGF9-dependent effect on astrocytes that disrupts in the growth factor milieu required to support myelination. We identify multiple downstream events induced by FGF9 associated with this effect including increased expression of leukaemia inhibitory growth factor (LIF) and FGF2, both of which are shown to inhibit myelination if present in excess. These studies identify FGF9-dependent signal transduction in astrocytes as a novel target for therapeutic strategies designed to enhance remyelination by endogenous OPC in MS. Gene expression profiles of rat myelinating cultures grown in the presence or absence of FGF9 (100 ng/ml) for 24h and 10 days were generated using Affymetrix GeneChip® Rat Gene 1.0 ST Arrays. Each time point (T1: 24 hrs, and T2: 10 days) has Control (CTR) and Treatment (FGF) groups, with two replicates in each group. In total, 8 arrays were generated from the four groups (CTR-T1, CTR-T2, FGF-T1 and FGF-T2).
2016-02-17 | E-GEOD-44562 | biostudies-arrayexpress
Project description:Mutations in Brg1 can cause Coffin-Siris syndrome, where a patient had white matter defects and partial agenesis of the corpus callosum; however, Brg1 functions in CNS myelination and remyelination is unsure. We show that PDGFRa expressed prior than NG2, depletion of Brg1 at PDGFRα+ OPC leads to OPC differentiation restriction and myelin defects, also, Brg1 is critical for oligodendrocyte remyelination. Genomic occupancy and transcriptome analyses indicate that Brg1 promotes H3K27me3 and neuronal genes. Thus our findings reveal that Brg1 is a critical epigenetic programmer of CNS myelination and repair through recruiting H3K27me3 and neuronal genes, suggesting potential strategies of therapeutic intervention for Brg1-associated white matter defects.
2024-03-25 | GSE205236 | GEO
Project description:The progressive loss of CNS myelin in patients with multiple sclerosis (MS) has been proposed to result from the combined effects of damage to oligodendrocytes and failure of remyelination. A common feature of demyelinated lesions is the presence of oligodendrocyte precursors (OLPs) blocked at a premyelinating stage. However, the mechanistic basis for inhibition of myelin repair is incompletely understood. To identify novel regulators of OLP differentiation, potentially dysregulated during repair, we performed a genome-wide screen of 1040 transcription factor-encoding genes expressed in remyelinating rodent lesions. We report that M-bM-^HM-<50 transcription factor-encoding genes show dynamic expression during repair and that expression of the Wnt pathway mediator Tcf4 (aka Tcf7l2) within OLPs is specific to lesionedM-bM-^@M-^Tbut not normalM-bM-^@M-^Tadult white matter. We report that M-NM-2-catenin signaling is active during oligodendrocyte development and remyelination in vivo. Moreover, we observed similar regulation of Tcf4 in the developing human CNS and lesions of MS. Data mining revealed elevated levels of Wnt pathway mRNA transcripts and proteins within MS lesions, indicating activation of the pathway in this pathological context. We show that dysregulation of WntM-bM-^@M-^SM-NM-2-catenin signaling in OLPs results in profound delay of both developmental myelination and remyelination, based on (1) conditional activation of M-NM-2-catenin in the oligodendrocyte lineage in vivo and (2) findings from APCMin mice, which lack one functional copy of the endogenous Wnt pathway inhibitor APC. Together, our findings indicate that dysregulated WntM-bM-^@M-^SM-NM-2-catenin signaling inhibits myelination/remyelination in the mammalian CNS. Evidence of Wnt pathway activity in human MS lesions suggests that its dysregulation might contribute to inefficient myelin repair in human neurological disorders. 12 samples total. Two variables in the experiment: genotype (wild type or Olig2cre/DA-Cat) and Developmental stage (Day 4 or Day 15). 4 phenotypes in total with 3 biological replicates for each phenotype.
2009-12-10 | E-GEOD-19403 | biostudies-arrayexpress
Project description:In Multiple Sclerosis (MS), inflammatory demyelinated lesions in the brain and spinal cord lead to neurodegeneration and progressive disability. Remyelination can restore fast saltatory conduction and neuroprotection but is inefficient in MS especially with increasing age, and is not yet improvable with therapies. Intrinsic and extrinsic inhibition of oligodendrocyte progenitor cell (OPC) function contributes to remyelination failure, and we hypothesised that the transplantation of ‘improved’ OPCs, genetically edited to overcome these obstacles, could improve remyelination. Here, we edited human(h) embryonic stem cell-derived OPCs to be unresponsive to a chemorepellent released from chronic MS lesions, and transplanted them into rodent models of chronic lesions. Edited hOPCs displayed enhanced migration and remyelination compared to controls, regardless of the host age and length of time post-transplant. This study demonstrates that genetic manipulation and transplantation of hOPCs overcomes the negative environment inhibiting remyelination, with translational implications for therapeutic strategies for people with progressive MS.
2023-08-23 | GSE241451 | GEO
Project description:Strategies for treating progressive multiple sclerosis (MS) remain limited. Here, we found that miR-145-5p is overabundant uniquely in chronic lesion tissues from secondary progressive MS patients. We induced both acute and chronic demyelination in miR-145 knockout mice to determine its contributions to remyelination failure. Following acute demyelination, no advantage to miR-145 loss could be detected. However, after chronic demyelination, animals with miR-145 loss demonstrated increased remyelination and functional recovery, coincident with altered presence of astrocytes and microglia within the corpus callosum relative to wild-type animals. This improved response in miR-145 knockout animals coincided with a pathological upregulation of miR-145-5p in wild-type animals with chronic cuprizone exposure, paralleling human chronic lesions. Furthermore, miR-145 overexpression specifically in oligodendrocytes (OLs) severely stunted differentiation and negatively impacted survival. RNAseq analysis showed altered transcriptome in these cells with downregulated major pathways involved in myelination. Our data suggest that pathological accumulation of miR-145-5p is a distinctive feature of chronic demyelination and is strongly implicated in the failure of remyelination, possibly due to the inhibition of OL differentiation together with alterations in other glial cells. This is mirrored in chronic MS lesions, and thus miR-145-5p serves as a potential relevant therapeutic target in progressive forms of MS.
2024-05-31 | GSE268808 | GEO
Project description:Background: Multiple sclerosis (MS) is an inflammation-mediated demyelinating disease of the central nervous system, which eventually results in secondary axonal degeneration due to remyelination failure. Successful remyelination is orchestrated by astrocytes (ASTRs) and requires sequential activation, recruitment, and maturation of oligodendrocyte progenitor cells (OPCs). In both MS and experimental models, remyelination is more robust in grey matter (GM) than white matter (WM) that is likely related to local differences between GM and WM lesions. Here, we investigated whether adult gmASTRs and wmASTRs differently modulate myelination. Methods: Differences in modulation of myelination between adult gmASTRs and wmASTRs were examined using in vitro myelinating cultures that rely on a feeding layer of ASTRs. Transcriptional profiling and weighted gene co-expression network analysis were used to analyze differentially expressed genes and gene networks. Potential differential modulation of OPC proliferation and maturation by adult gmASTRs and wmASTRs, in response to Toll-like receptor (TLR) 3 and TLR4 agonists, were assessed. Results: Our data reveal that adult wmASTRs are less supportive to in vitro myelination than gmASTRs. WmASTRs more abundantly express reactive ASTR genes and genes of a neurotoxic subtype of ASTRs, while gmASTRs have more neuro-reparative transcripts. A gene network module, containing cholesterol biosynthesis enzyme genes that positively correlated with gmASTRs, and a network module, containing extracellular matrix-related genes that positively correlated with wmASTRs, are identified. Adult wmASTRs and gmASTRs responding to TLR3 agonist Poly(I:C) differently modulate OPC behavior, while LPS treatment of both gmASTRs and wmASTRs results in a prominent decrease in myelin membrane formation. Conclusions: Primary adult gmASTRs and wmASTRs are heterogeneous at the transcriptional level, differed in their support of in vitro myelination, and their pre-existing phenotype determined TLR3 agonist responses. These findings point to a role of ASTR heterogeneity in regional differences in remyelination efficiency between GM and WM lesions.
2020-12-21 | GSE155866 | GEO
Project description:The progressive loss of CNS myelin in patients with multiple sclerosis (MS) has been proposed to result from the combined effects of damage to oligodendrocytes and failure of remyelination. A common feature of demyelinated lesions is the presence of oligodendrocyte precursors (OLPs) blocked at a premyelinating stage. However, the mechanistic basis for inhibition of myelin repair is incompletely understood. To identify novel regulators of OLP differentiation, potentially dysregulated during repair, we performed a genome-wide screen of 1040 transcription factor-encoding genes expressed in remyelinating rodent lesions. We report that ∼50 transcription factor-encoding genes show dynamic expression during repair and that expression of the Wnt pathway mediator Tcf4 (aka Tcf7l2) within OLPs is specific to lesioned—but not normal—adult white matter. We report that β-catenin signaling is active during oligodendrocyte development and remyelination in vivo. Moreover, we observed similar regulation of Tcf4 in the developing human CNS and lesions of MS. Data mining revealed elevated levels of Wnt pathway mRNA transcripts and proteins within MS lesions, indicating activation of the pathway in this pathological context. We show that dysregulation of Wnt–β-catenin signaling in OLPs results in profound delay of both developmental myelination and remyelination, based on (1) conditional activation of β-catenin in the oligodendrocyte lineage in vivo and (2) findings from APCMin mice, which lack one functional copy of the endogenous Wnt pathway inhibitor APC. Together, our findings indicate that dysregulated Wnt–β-catenin signaling inhibits myelination/remyelination in the mammalian CNS. Evidence of Wnt pathway activity in human MS lesions suggests that its dysregulation might contribute to inefficient myelin repair in human neurological disorders.
2009-12-10 | GSE19403 | GEO
Project description:Regional differences in neurons, astrocytes, oligodendrocytes, and microglia exist in the brain during health, and regional differences in the transcriptome may occur for each cell type during neurodegeneration. Multiple sclerosis (MS) is multifocal, and regional differences in the astrocyte transcriptome occur in experimental autoimmune encephalomyelitis (EAE), an MS model. MS and EAE are characterized by inflammation, demyelination, and axonal damage, with minimal remyelination. Here, RNA-sequencing analysis of MS tissues from six brain regions suggested a focus on oligodendrocyte lineage cells (OLCs) in corpus callosum. Olig1-RiboTag mice were used to determine the translatome of OLCs in vivo in corpus callosum during the remyelination phase of a chronic cuprizone model with axonal damage. Cholesterol-synthesis gene pathways dominated as the top up-regulated pathways in OLCs during remyelination. In EAE, remyelination was induced with estrogen receptor-β (ERβ) ligand treatment, and up-regulation of cholesterol-synthesis gene expression was again observed in OLCs. ERβ-ligand treatment in the cuprizone model further increased cholesterol synthesis gene expression and enhanced remyelination. Conditional KOs of ERβ in OLCs demonstrated that increased cholesterol-synthesis gene expression in OLCs was mediated by direct effects in both models. To address this direct effect, ChIP assays showed binding of ERβ to the putative estrogen-response element of a key cholesterol-synthesis gene (Fdps). As fetal OLCs are exposed in utero to high levels of estrogens in maternal blood, we discuss how remyelinating properties of estrogen treatment in adults during injury may recapitulate normal developmental myelination through targeting cholesterol homeostasis in OLCs.
2019-04-29 | GSE118451 | GEO
Project description:Remyelination failure contributes to axonal dysfunction in neurodegenerative disorders. But whether astrocytes, the most abundant glial cell type in demyelinated lesions, support or impede remyelination is controversial. Following focal demyelinated lesions of the mouse corpus callosum induced with the myelin toxin lysolecithin, we used TRAP (translational ribosome affinity purification) sequencing to isolate and sequence ribosome-associated mRNAs which are being actively translated in astrocytes, and studied how the responses and molecular mechanisms in astrocytes are linked to remyelination.
2023-05-17 | E-MTAB-9270 | biostudies-arrayexpress
Project description:Extrinsic inhibitors at sites of blood-brain barrier (BBB) disruption and neurovascular damage contribute to remyelination failure in neurological diseases. However, therapies to overcome extrinsic inhibition of remyelination are not widely available and the dynamics of glial progenitor niche remodeling at site of neurovascular dysfunction are largely unknown. By integrating in vivo two-photon (2P) imaging co-registered with electron microscopy and transcriptomics in chronic neuroinflammatory lesions, we found repressed anticoagulation pathways in oligodendrocyte precursor cells (OPCs) that clustered perivascularly at sites of limited remyelination with deposition of fibrinogen, a blood coagulation factor abundantly deposited in multiple sclerosis lesions. By developing the OPC-X-screen to identify compounds that promote remyelination in the presence of extrinsic inhibitors, we showed that known promyelinating drugs did not rescue extrinsic inhibition of remyelination by fibrinogen. In contrast, bone morphogenetic protein (BMP) receptor blockade rescued the inhibitory fibrinogen effects and restored a promyelinating progenitor niche by promoting myelinating oligodendrocytes, while suppressing astrocyte cell fate with potent therapeutic effects in chronic models of multiple sclerosis. Thus, abortive OPC differentiation by fibrinogen is refractory to known promyelinating compounds, suggesting that blockade of the BMP signaling pathway may enhance remyelinating efficacy by overcoming extrinsic inhibition in neuroinflammatory lesions with vascular damage.
2021-08-24 | GSE166675 | GEO