Search results for "Oligodendroglia"
showing 10 items of 75 documents
Mice lacking Plexin-B3 display normal CNS morphology and behaviour
2009
Semaphorins and their receptors, plexins, have emerged as important regulators of a multitude of biological processes. Plexin-B3 has been shown to be selectively expressed in postnatal oligodendrocytes. In contrast to the well-characterized Plexin-A family and the Plexin-B family members Plexin-B1 and -B2, no data are available on the functional role of Plexin-B3 in the central nervous system in vivo. Here we have elucidated the functional significance of Plexin-B3 by generating and analyzing constitutive knock-out mice. Plexin-B3-deficient mice were found to be viable and fertile. A systematic histological analysis revealed no morphological defects in the brain or spinal cord of mutant ani…
Apoptosis of oligodendrocytes via Fas and TNF-R1 is a key event in the induction of experimental autoimmune encephalomyelitis.
2005
Abstract In experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis, immunization with myelin Ags leads to demyelination and paralysis. To investigate which molecules are crucial for the pathogenesis of EAE, we specifically assessed the roles of the death receptors Fas and TNF-R1. Mice lacking Fas expression in oligodendrocytes (ODCs) were generated and crossed to TNF-R1-deficient mice. To achieve specific deletion of a loxP-flanked fas allele in ODCs, we generated a new insertion transgene, expressing the Cre recombinase specifically in ODCs. Fas inactivation alone as well as the complete absence of TNF-R1 protected mice partially from EAE induced by the imm…
Primary oligodendrocyte death does not elicit anti-CNS immunity.
2012
Anti-myelin immunity is commonly thought to drive multiple sclerosis, yet the initial trigger of this autoreactivity remains elusive. One of the proposed factors for initiating this disease is the primary death of oligodendrocytes. To specifically test such oligodendrocyte death as a trigger for anti-CNS immunity, we inducibly killed oligodendrocytes in an in vivo mouse model. Strong microglia-macrophage activation followed oligodendrocyte death, and myelin components in draining lymph nodes made CNS antigens available to lymphocytes. However, even conditions favoring autoimmunity-bystander activation, removal of regulatory T cells, presence of myelin-reactive T cells and application of dem…
Reversible neural stem cell niche dysfunction in a model of multiple sclerosis
2011
Objective The subventricular zone (SVZ) of the brain constitutes a niche for neural stem and progenitor cells that can initiate repair after central nervous system (CNS) injury. In a relapsing-remitting model of experimental autoimmune encephalomyelitis (EAE), the neural stem cells (NSCs) become activated and initiate regeneration during acute disease, but lose this ability during the chronic phases of disease. We hypothesized that chronic microglia activation contributes to the failure of the NSC repair potential in the SVZ. Methods Using bromodeoxyuridine injections at different time points during EAE, we quantified the number of proliferating and differentiating progenitors, and evaluate…
Oligodendrocyte-specific FADD deletion protects mice from autoimmune-mediated demyelination.
2010
Abstract Apoptosis of oligodendrocytes (ODCs), the myelin-producing glial cells in the CNS, plays a central role in demyelinating diseases such as multiple sclerosis and experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. To investigate the mechanism behind ODC apoptosis in EAE, we made use of conditional knockout mice lacking the adaptor protein FADD specifically in ODCs (FADDODC-KO). FADD mediates apoptosis by coupling death receptors with downstream caspase activation. In line with this, ODCs from FADDODC-KO mice were completely resistant to death receptor-induced apoptosis in vitro. In the EAE model, FADDODC-KO mice followed an ameliorated clinical di…
Epigenetic modifiers are necessary but not sufficient for reprogramming non-myelinating cells into myelin gene-expressing cells.
2010
Background Modifications on specific histone residues and DNA methylation play an essential role in lineage choice and cellular reprogramming. We have previously shown that histone modifications or combinatorial codes of transcription factors (TFs) are critical for the differentiation of multipotential progenitors into myelinating oligodendrocytes. In this study we asked whether combining global manipulation of DNA methylation and histone acetylation together with the expression of oligodendrocyte- specific TFs, was sufficient to switch the identity of fibroblasts into myelin gene-expressing cells. Methodology/Principal Findings Transfection of six oligodendrocyte-specific TFs (Olig1, Olig2…
A Cre-inducible diphtheria toxin receptor mediates cell lineage ablation after toxin administration.
2004
A new system for lineage ablation is based on transgenic expression of a diphtheria toxin receptor (DTR) in mouse cells and application of diphtheria toxin (DT). To streamline this approach, we generated Cre-inducible DTR transgenic mice (iDTR) in which Cre-mediated excision of a STOP cassette renders cells sensitive to DT. We tested the iDTR strain by crossing to the T cell- and B cell-specific CD4-Cre and CD19-Cre strains, respectively, and observed efficient ablation of T and B cells after exposure to DT. In MOGi-Cre/iDTR double transgenic mice expressing Cre recombinase in oligodendrocytes, we observed myelin loss after intraperitoneal DT injections. Thus, DT crosses the blood-brain bar…
Activation of oligodendroglial Fyn kinase enhances translation of mRNAs transported in hnRNP A2-dependent RNA granules.
2008
Central nervous system myelination requires the synthesis of large amounts of myelin basic protein (MBP) at the axon–glia contact site. MBP messenger RNA (mRNA) is transported in RNA granules to oligodendroglial processes in a translationally silenced state. This process is regulated by the trans-acting factor heterogeneous nuclear ribonucleoprotein (hnRNP) A2 binding to the cis-acting A2 response element (A2RE). Release of this repression of MBP mRNA translation is thus essential for myelination. Mice deficient in the Src family tyrosine kinase Fyn are hypomyelinated and contain reduced levels of MBP. Here, we identify hnRNP A2 as a target of activated Fyn in oligodendrocytes. We show that…
Heterogeneous nuclear ribonucleoprotein (hnRNP) F is a novel component of oligodendroglial RNA transport granules contributing to regulation of myeli…
2011
Myelin basic protein (MBP) is a major component of central nervous system (CNS) myelin. The absence of MBP results in the loss of almost all compact myelin in the CNS. MBP mRNA is sorted into RNA granules that are transported to the periphery of oligodendrocytes in a translationally inactive state. A central mediator of this transport process is the trans-acting factor heterogeneous nuclear ribonucleoprotein (hnRNP) A2 that binds to the cis-acting A2-response element in the 3′UTR of MBP mRNA. Recently, we found that activation of the Src family nonreceptor tyrosine kinase Fyn in oligodendrocytes leads to phosphorylation of hnRNP A2 and to increased translation of MBP mRNA. Here, we identify…
Interaction of syntenin-1 and the NG2 proteoglycan in migratory oligodendrocyte precursor cells.
2008
Migration of oligodendrocyte precursors along axons is a necessary prerequisite for myelination, but little is known about underlying mechanisms. NG2 is a large membrane proteoglycan implicated in oligodendrocyte migration. Here we show that a PDZ domain protein termed syntenin-1 interacts with NG2 and that syntenin-1 is necessary for normal rates of migration. The association of syntenin-1 with NG2, identified in a yeast two-hybrid screen, was confirmed by colocalization of both proteins within processes of oligodendroglial precursor cells and by coimmunoprecipitation from cell extracts. Syntenin-1 also colocalizes with NG2 in "co-capping" assays, demonstrating a lateral association of bot…