Project description:Background During the development of the central nervous system, oligodendrocytes generate large amounts of myelin, a multilayered insulating membrane that ensheathes axons, thereby allowing the fast conduction of the action potential and maintaining axonal integrity. Differentiation of oligodendrocytes to myelin-forming cells requires the downregulation of RhoA GTPase activity. Results To gain insights into the molecular mechanisms of oligodendrocyte differentiation, we performed microarray expression profiling of the oligodendroglial cell line, Oli-neu, treated with the Rho kinase (ROCK) inhibitor, Y-27632 or with conditioned neuronal medium. This resulted in the identification of the transmembrane protein 10 (Tmem10/Opalin), a novel type I transmembrane protein enriched in differentiating oligodendrocytes. In primary cultures, Tmem10 was abundantly expressed in O4-positive oligodendrocytes, but not in oligodendroglial precursor cells, astrocytes, microglia or neurons. In mature oligodendrocytes Tmem10 was enriched in the rims and processes of the cells and was only found to a lesser extent in the membrane sheets. Conclusions Together, our results demonstrate that Tmem10 is a novel marker for in vitro generated oligodendrocytes. Keywords: gene expression profiling for oligodendrocytes, olineu, oligodendrocyte differentiation
Project description:Background; During the development of the central nervous system, oligodendrocytes generate large amounts of myelin, a multilayered insulating membrane that ensheathes axons, thereby allowing the fast conduction of the action potential and maintaining axonal integrity. Differentiation of oligodendrocytes to myelin-forming cells requires the downregulation of RhoA GTPase activity. Results; To gain insights into the molecular mechanisms of oligodendrocyte differentiation, we performed microarray expression profiling of the oligodendroglial cell line, Oli-neu, treated with the Rho kinase (ROCK) inhibitor, Y-27632 or with conditioned neuronal medium. This resulted in the identification of the transmembrane protein 10 (Tmem10/Opalin), a novel type I transmembrane protein enriched in differentiating oligodendrocytes. In primary cultures, Tmem10 was abundantly expressed in O4-positive oligodendrocytes, but not in oligodendroglial precursor cells, astrocytes, microglia or neurons. In mature oligodendrocytes Tmem10 was enriched in the rims and processes of the cells and was only found to a lesser extent in the membrane sheets. Conclusions; Together, our results demonstrate that Tmem10 is a novel marker for in vitro generated oligodendrocytes. Experiment Overall Design: 2 Subexperiments: Experiment Overall Design: 1. olineu in absence of neurons (control) vs. olineu in presence of neurons Experiment Overall Design: including dye swap design with 6 technical replicates Experiment Overall Design: 2. olineu in presence of neurons (control) vs. Y27631 treated olineu in presence of neurons
Project description:Inadequate remyelination of brain white matter lesions has been associated with a failure of oligodendrocyte precursors to differentiate into mature, myelin-producing cells. In order to better understand which genes play a specific role in oligodendrocyte differentiation we performed time dependent, genome-wide gene expression studies of mouse Oli-neu cells as they differentiate into myelin basic protein-producing cells, following treatment with three different agents. Our data indicate that different inducers activate distinct pathways that ultimately converge into the differentiated state where regulated gene sets overlap maximally. In order to also gain insight into the functional role of genes that are regulated in this process, we silenced 88 of these genes using siRNA, and identified multiple repressors of spontaneous differentiation of Oli-neu, most of which were confirmed in rat primary oligodendrocyte precursors cells. Among these repressors were CNPase, a well-known myelin constituent, and three phosphatases, each known to negatively control MAP kinase cascades. We show that a novel inhibitor for one of the identified genes, dual-specificity phosphatase DUSP10/MKP5, was also capable of inducing oligodendrocyte differentiation in primary oligodendrocyte precursors. Oligodendrocytic differentiation feedback loops may therefore yield pharmacological targets to treat disease related to dysfunctional myelin deposition Experiment Overall Design: triplicates for 3 times points 10h, 24h, 72h in 6 conditions, Forskolin, Insulin, Dexamethasone, Retinoic Acid, PD174265, Untreated. Arrays were done in two distinct experiments 1 and 2. Some replicates are missing because of lab operating issues
Project description:Inadequate remyelination of brain white matter lesions has been associated with a failure of oligodendrocyte precursors to differentiate into mature, myelin-producing cells. In order to better understand which genes play a specific role in oligodendrocyte differentiation we performed time dependent, genome-wide gene expression studies of mouse Oli-neu cells as they differentiate into myelin basic protein-producing cells, following treatment with three different agents. Our data indicate that different inducers activate distinct pathways that ultimately converge into the differentiated state where regulated gene sets overlap maximally. In order to also gain insight into the functional role of genes that are regulated in this process, we silenced 88 of these genes using siRNA, and identified multiple repressors of spontaneous differentiation of Oli-neu, most of which were confirmed in rat primary oligodendrocyte precursors cells. Among these repressors were CNPase, a well-known myelin constituent, and three phosphatases, each known to negatively control MAP kinase cascades. We show that a novel inhibitor for one of the identified genes, dual-specificity phosphatase DUSP10/MKP5, was also capable of inducing oligodendrocyte differentiation in primary oligodendrocyte precursors. Oligodendrocytic differentiation feedback loops may therefore yield pharmacological targets to treat disease related to dysfunctional myelin deposition Keywords: time course
Project description:We investigated the effects of nimodipine, a L-type voltage-gated calcium channel antagonist, on the expression profile of myelin genes in the oligodendrocyte precursor cell (OPC) line Oli-Neu. We performed gene expression profiling analysis using data obtained from RNA-seq of four biological replicates for treatment and four replicates for control condition.
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.
Project description:The oligodendrocyte (OL) lineage gene Olig2 persistently expresses throughout oligodendroglial development and required for oligodendroglial specification and differentiation. Here, Together, by leveraging multiple immature OL-expressing Cre lines at different stages, we demonstrate that Olig2 is required for differentiation and myelination of immature OL and myelin repair and raise fundamental questions about the previously proposed role for Olig2 in opposing OL myelination, while highlighting the importance of using Cre-dependent reporter for lineage tracing in studying cell fate transition.
Project description:Multiple sclerosis (MS) is the most frequent demyelinating disease and despite significant advances in the immunotherapy, disease progression still cannot be prevented. Promotion of remyelination, an endogenous repair process, represents a promising new treatment approach. However, spontaneous remyelination frequently fails in MS lesions due to an impaired differentiation of progenitor cells into mature, myelinating oligodendrocytes. Intrinsic oligodendroglial and extrinsic inflammatory factors may contribute to this differentiation block. Therefore, we compared induced pluripotent stem cell (iPSC)-derived oligodendrocytes (hiOL) from MS patients and healthy controls as well as their response to extrinsic factors. While functional capabilities or proteome compostion of both cell types were virtually indistinguishable, we discovered that Interferon-gamma (IFNγ) producing immune cells significantly impaired oligodendroglial differentiation and observed no differences in the functional capabilities or the proteome. In summary, these data indicate that the oligodendroglial differentiation block is not due to intrinsic oligodendroglial factors, but rather caused by the inflammatory environment present in MS lesions. These findings may contribute to the development of remyelination promoting strategies in MS.
Project description:The aim of this study was to identify differentially expressed genes in peripheral blood mononuclear cells from MS patients that were responders or non-responders to the neuroantigen myelin basic protein. Using microarray we measured mRNA-expression levels in freshly isolated peripheral blood mononuclear cells from 17 untreated patients with multiple sclerosis. Based on studies, measuring the responses of blood derived T-cells to myelin basic protein ex vivo, these 17 untreated MS-patients can be divided into two groups: 4 of the untreated multiple sclerosis patients had T-cells that responded to myelin basic protein ex vivo whereas 13 untreated MS patients had T-cells that did not respond to myelin basic protein ex vivo.