Astrocyte-Derived Clusterin Disrupts Glial Physiology to Obstruct Remyelination in Mouse Models of Demyelinating Diseases
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE275514 | GEO | 2024/08/23
REPOSITORIES: GEO
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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:Multiple Sclerosis (MS) is a neuroinflammatory disease characterized by demyelinated lesions in the CNS. Remyelination in MS is variable between individuals and tends to become less efficient with aging. Microglia and astrocytes are known to have critical roles in MS pathogenesis, but to what extent their activity is altered by remyelination failure remains unclear. To determine the effects of demyelination on neuroinflammation, we use two mouse models that genetically ablate myelinating oligodendrocytes. We use the Plp1-CreERT mouse line crossed with the Myrf fl/fl mouse line to induce genetic demyelination throughout the CNS following adult tamoxifen administration. Subsequent remyelination is mediated by the proliferation and differentiation of oligodendrocyte precursor cells (OPCs) to newly formed oligodendrocytes. To assess the consequences of remyelination failure, we deleted Myrf from both mature oligodendrocytes and OPCs using Myrf fl/fl; Sox10-CreERT mice, which both induces demyelination and impairs subsequent remyelination. To characterize the glial cells in these demyelinated mice, we performed single-nucleus RNA-sequencing (snRNAseq) of optic nerves at peak demyelination, generating an atlas of non-neuronal cells including oligodendrocyte lineage cells, astrocytes, microglia, endothelial cells, pericytes, arachnoid barrier cells, vascular and leptomeningeal cells.
2024-09-12 | GSE243788 | GEO
Project description:Multiple sclerosis (MS) is characterized by demyelinated lesions in the central nervous system. Destruction of myelin and secondary damage to axons and neurons leads to significant disability, particularly in people with progressive MS. Accumulating evidence suggests that the potential for myelin repair exists in MS, although for unclear reasons this process fails. The cells responsible for producing myelin, the oligodendrocytes, and their progenitors oligodendrocyte precursor cells (OPCs) have been identified at the site of lesions, even in adults. Their presence suggests the possibility that endogenous remyelination without transplantation of donor stem cells may be a strategy for myelin repair in MS. Strategies to develop novel therapies have focused on induction of signaling pathways that stimulate OPCs to mature into myelin-producing oligodendrocytes that could then possibly remyelinate lesions. We have been investigating pharmacological approaches to enhance OPC differentiation, and have identified that the combination of two agents, triiodothyronine (T3) and quetiapine, leads to an additive effect on OPC differentiation and consequent myelin production via both overlapping and distinct signaling pathways. While the ultimate production of myelin requires cholesterol biosynthesis, we identified that quetiapine enhances gene expression in this pathway more potently than T3. Two blockers of cholesterol production, betulin and simvastatin, reduced OPC differentiation into myelin producing oligodendrocytes. Elucidating the nature of agents that lead to complementary and additive effects, possibly even synergistic effects, on oligodendrocyte differentiation and myelin production may pave the way for more efficient induction of remyelination in people with MS.
2019-07-30 | GSE125325 | GEO
Project description:In multiple sclerosis (MS) and experimental models of demyelination, myelin repair is mostly achieved by oligodendrocyte precursor cells (OPCs). To gain insight into the biological specificity of these adult precursors, in the perspective to better understand why remyelination often fails in MS, we performed a micro-array analysis on purified populations of murine OPCs and oligodendrocytes. We demonstrated that, in a control environment, M-bM-^@M-^\quiescentM-bM-^@M-^] adult OPCs are more mature than neonatal OPCs, with a mRNA profile closer to oligodendrocytes. However, when demyelination occurs, adult OPCs revert to an immature gene expression profile, acquiring higher migration and faster differentiation capacities. Among the many genes differentially regulated by these M-bM-^@M-^\activatedM-bM-^@M-^] adult OPCs, genes of the innate immune response, IL1M-NM-2 and CCL2 were strongly upregulated after demyelination, with increased protein expression in experimental demyelinating lesions and within MS plaques. We first showed in vitro that both IL1M-NM-2 and CCL2 M-bM-^@M-^\accountM-bM-^@M-^] for increased migration capacities of adult OPCs, an effect that is suppressed by corresponding receptor blockade. Focusing on Ccl2, we then demonstrated that lentiviral over-expression of Ccl2 increases motility of M-bM-^@M-^\quiescentM-bM-^@M-^] adult OPCs, which become as mobile as M-bM-^@M-^\activatedM-bM-^@M-^] adult OPCs. This in vitro gain of function was further confirmed in vivo, by showing an increased migration of grafted CG4 oligodendroglial cells over-expressing-Ccl2. These results, demonstrating that M-bM-^@M-^\activatedM-bM-^@M-^] adult OPCs upregulate immune cues favouring their migration, open new perspective of demyelination-induced immune-glial interactions, which might influence both oligodendroglial and inflammatory cells, therefore play a key role in lesion fate in multiple sclerosis. In this study, we loaded purified population of progenitors of oligodendrocytes (OPCs) (from neonatal, 2-month-old, 2-month-old and cuprizone-treated brains) and of mature oligodendrocytes (OLs) (2-month-old brains) and compared their gene expression. We compared gene expression of neonatal OPCs, adult OPCs, adult OLs and adult OPCs from control conditions and from demyelinating conditions, using 3 to 4 independant replicates in each group.
2014-11-06 | E-GEOD-48872 | 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
Project description:Clusterin (CLU) is a stress-activated molecular chaperone that confers treatment resistance to taxanes when highly expressed. While CLU inhibition potentiates activity of taxanes and other anti-cancer therapies in preclinical models, progression to treatment resistant disease still occurs implicating additional compensatory survival mechanisms. Taxanes are believed to selectively target cells in mitosis, a complex mechanism controlled in part by balancing antagonistic roles of Cdc25C and Wee1 in mitosis progression. Our data indicate that CLU silencing induces a constitutive activation of Cdc25C, which delays mitotic exit and hence sensitizes cancer cells to mitotic-targeting agents such taxanes. Unchecked Cdc25C activation leads to mitotic catastrophe and cell death unless cells upregulate protective mechanisms mediated through the cell cycle regulators Wee1 and Cdc2. In this study we show that CLU silencing induces a constitutive activation of Cdc25C via the phosphatase PP2A but leads to relief of negative feedback inhibition and activation of Wee1-Cdc2 to promote survival and limit therapeutic efficacy. Simultaneous inhibition of CLU-regulated cell cycle effectors, like PP2A and Wee1, may improve synergistic responses of biologically rational combinatorial regimens using taxanes and CLU inhibitors Biological triplicate of PC3 treated with siClusterin were compared to biological trplicate of PC3 treated with siScramblein
2016-03-01 | E-GEOD-67256 | biostudies-arrayexpress
Project description:In multiple sclerosis (MS) and experimental models of demyelination, myelin repair is mostly achieved by oligodendrocyte precursor cells (OPCs). To gain insight into the biological specificity of these adult precursors, in the perspective to better understand why remyelination often fails in MS, we performed a micro-array analysis on purified populations of murine OPCs and oligodendrocytes. We demonstrated that, in a control environment, “quiescent” adult OPCs are more mature than neonatal OPCs, with a mRNA profile closer to oligodendrocytes. However, when demyelination occurs, adult OPCs revert to an immature gene expression profile, acquiring higher migration and faster differentiation capacities. Among the many genes differentially regulated by these “activated” adult OPCs, genes of the innate immune response, IL1β and CCL2 were strongly upregulated after demyelination, with increased protein expression in experimental demyelinating lesions and within MS plaques. We first showed in vitro that both IL1β and CCL2 “account” for increased migration capacities of adult OPCs, an effect that is suppressed by corresponding receptor blockade. Focusing on Ccl2, we then demonstrated that lentiviral over-expression of Ccl2 increases motility of “quiescent” adult OPCs, which become as mobile as “activated” adult OPCs. This in vitro gain of function was further confirmed in vivo, by showing an increased migration of grafted CG4 oligodendroglial cells over-expressing-Ccl2. These results, demonstrating that “activated” adult OPCs upregulate immune cues favouring their migration, open new perspective of demyelination-induced immune-glial interactions, which might influence both oligodendroglial and inflammatory cells, therefore play a key role in lesion fate in multiple sclerosis.
2014-11-06 | GSE48872 | GEO
Project description:Multiple sclerosis (MS) is a neuroimmune disorder characterized by inflammation, CNS demyelination, and progressive neurodegeneration. Chronic MS patients exhibit impaired remyelination capacity, partly due to the changes that oligodendrocyte precursor cells (OPCs) undergo in response to the MS lesion environment. The cytokine tumor necrosis factor (TNF) is present in the MS affected CNS and has been implicated in disease pathophysiology. Of the two active forms of TNF, transmembrane (tmTNF) and soluble (solTNF), tmTNF signals via TNFR2 mediating protective and reparative effects, including remyelination, whereas solTNF signals predominantly via TNFR1 promoting neurotoxicity. To better understand the mechanisms underlying repair failure in MS, we investigated the cellular responses of OPCs to inflammatory exposure and the specific role of TNFR2 signaling in their modulation. Following treatment of cultured OPCs with IFNg, IL1b and TNF we observed by RNA sequencing marked inflammatory and immune activation of OPCs, accompanied by metabolic changes and dysregulation of their proliferation and differentiation programming. We also established the high likelihood of cell-cell interaction between OPCs and microglia in neuroinflammatory conditions, with OPCs able to produce chemokines that can recruit and activate microglia. Importantly, we showed that these functions are exacerbated when TNFR2 is ablated. Together, our data indicate that neuroinflammation leads OPCs to shift towards an immunomodulatory phenotype while diminishing their capacity to proliferate and differentiate, thus impairing their repair function. Furthermore, we demonstrated that TNFR2 plays a key role in this process, suggesting that boosting TNFR2 activation or its downstream signals could be an effective strategy to restore OPC reparative capacity in demyelinating disease.
2021-07-28 | GSE180604 | GEO
Project description:Astrocytes are instrumental in both maintaining CNS homeostasis and responding to tissue injury. While astrocyte activation may be a beneficial response to acute pathologies, prolonged reactive gliosis is thought to be injurious in neurodegenerative diseases, including multiple sclerosis (MS). A major limitation of studying neurodegenerative diseases is lack of human pathological specimens obtained during the acute stages, thereby relegating research to post mortem specimens often obtained years after the initiation of pathology. Rodent reactive astrocytes have been shown to be cytotoxic to neurons and oligodendrocytes but may differ from human cells, especially in diseases with known genetic susceptibility. Herein, we purified human CD49f+ astrocytes from differentiated induced pluripotent stem cells derived from individual patient and control peripheral white blood cell samples. We compared TNF and IL1a stimulated human reactive astrocytes from 7 persons with MS and 6 non-MS controls and show their specific astrocyte transcriptomic profiles are remarkably similar to those described in rodents. The functional effect of astrocyte conditioned media (ACM) was examined in a human oligodendrocyte precursor cell (OPC) line differentiation assay using a transgenic secreted reporter of myelin basic protein (MBP) expression. ACM was not cytotoxic to the OPCs but robustly inhibited the MBP reporter. No differences were seen between MS and control stimulated astrocytes at either the transcript level or in functional OPC suppression assays. We next used RNAseq to interrogate differentially expressed genes in the OPC lines that had suppressed differentiation from the human ACM. Remarkably, not only was OPC differentiation and myelin gene expression suppressed, but we observed induction of several immune pathways and Nf-κB signaling in OPCs exposed to the ACM. These data support the notion that reactive astrocytes can inhibit OPC differentiation thereby limiting their remyelination capacity, and that OPCs take on an immune profile in the context of inflammatory cues.
2022-02-14 | GSE196575 | GEO
Project description:Clusterin (CLU) is one of the most significant genetic risk factors for late onset Alzheimer’s disease. Numerous studies have now demonstrated that CLU-AD mutations and amyloid-β (Aβ) treatment alter the trafficking and localisation of glycosylated CLU. iPSCs with altered CLU trafficking were generated following the removal of CLU exon 2 by CRISPR/Cas9 gene editing. Neurons were generated from control, unedited and exon 2 -/- iPSCs and were incubated with aggregated Aβ peptides. Changes in cell death and neurite length were quantified to determine if altered CLU protein trafficking influenced neuronal sensitivity to Aβ.
2022-07-05 | GSE207466 | GEO