Publications by authors named "Sjef Copray"

CAG-repeat expansions in at least eight different genes cause neurodegeneration. The length of the extended polyglutamine stretches in the corresponding proteins is proportionally related to their aggregation propensity. Although these proteins are ubiquitously expressed, they predominantly cause toxicity to neurons.

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Parkinson's disease (PD) is characterized by the presence of insoluble protein clusters containing α-synuclein. Impairment of mitochondria, endoplasmic reticulum, autophagy and intracellular trafficking proper function has been suggested to be caused by α-synuclein toxicity, which is also associated with the higher levels of ROS found in the aged brain and in PD. Oxidative stress leads to protein oligomerization and aggregation that impair autophagy and mitochondrial dynamics leading to a vicious cycle of organelles damage and neurodegeneration.

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The gene that encodes N-acetyltransferase 2 (NAT2), an enzyme that plays a crucial role in the metabolism of many drugs and xenobiotics, is located on chromosome 8p22, one of the most convictive susceptibility loci of schizophrenia. NAT2 genetic polymorphisms lead to various enzyme acetylation phenotypes. In the present study, six selected NAT2 exonic single nucleotide polymorphisms were genotyped in an independent case-control sample of a Northern Chinese Han population to verify the possible association between NAT2 and schizophrenia.

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Both resident innate and peripheral immune aberrations have been demonstrated to influence Parkinson's disease (PD) progression. However, it is still enigmatic how and which immune components are lethal to the dopaminergic neuron in PD. We now show that levels of perforin, a pore-forming protein expressed in cytotoxic immune cells, was significantly increased in the serum of wild-type mice 4 weeks after injection of MPTP, a toxin used to induce PD-like symptoms.

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Article Synopsis
  • Researchers found a way to use special cells from human stem cells to help fix damaged nerves in people with multiple sclerosis (MS).
  • These special cells, called OPCs, can move to areas where nerves are hurt and start rebuilding the protective covering around them.
  • This study is important because it could lead to new treatments for MS, helping people who currently don't have effective options to feel better and preserve their nerves.
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Intrastriatal transplantation of dopaminergic neurons has been shown to be a potentially very effective therapeutic approach for the treatment of Parkinson's disease (PD). With the detection of induced pluripotent stem cells (iPSCs), an unlimited source of autologous dopaminergic (DA) neurons became available. Although the iPSC-derived dopaminergic neurons exhibited most of the fundamental dopaminergic characteristics, detailed analysis and comparison with primary DA neurons have shown some aberrations in the expression of genes involved in neuronal development and neurite outgrowth.

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New developments in stem cell biology offer alternatives for the reconstruction of critical-sized bone defects. One of these developments is the use of induced pluripotent stem (iPS) cells. These stem cells are similar to embryonic stem (ES) cells, but can be generated from adult somatic cells and therefore do not raise ethical concerns.

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Glioblastoma (GBM) is a highly infiltrative brain tumor in which cells with properties of stem cells, called glioblastoma stem cells (GSCs), have been identified. In general, the dominant view is that GSCs are responsible for the initiation, progression, invasion and recurrence of this tumor. In this study, we addressed the question whether the differentiation status of GBM cells is associated with their invasive capacity.

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Neuronal degeneration within the substantia nigra and the loss of the dopaminergic nigro-striatal pathway are the major hallmarks of Parkinson's disease (PD). Grafts of foetal ventral mesencephalic (VM) dopaminergic (DA) neurons into the striatum have been shown to be able to restore striatal dopamine levels and to improve overall PD symptoms. However, human foetus-derived cell grafts are not feasible for clinical application.

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Stroke is the second most common cause of death and the leading cause of disability in the world. About 30% of the people that are affected by stroke die within a year; 25% of the patients that survive stroke remain in need of care after a year. Therefore, stroke is a major burden for health care costs.

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The present study describes for the first time the neural expression and distribution of UGS148, a protein encoded by the RIKEN cDNA63330403K07 gene that has been shown to be prominently and characteristically expressed in neural stem cells (NSCs). Based on its molecular structure, UGS148 is an intracellular protein expected to be involved in intracellular sorting, trafficking, exocytosis and membrane insertion of proteins. We demonstrate that UGS148 is highly expressed in embryonic NSCs as well as, albeit at low level, in the adult neurogenic niches, the subventricular zone and the hippocampal dentate gyrus.

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Tissue engineering of Schwann cells (SCs) can serve a number of purposes, such as in vitro SC-related disease modeling, treatment of peripheral nerve diseases or peripheral nerve injury, and, potentially, treatment of CNS diseases. SCs can be generated from autologous stem cells in vitro by recapitulating the various stages of in vivo neural crest formation and SC differentiation. In this review, we survey the cellular and molecular mechanisms underlying these in vivo processes.

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Studies on myelination and oligodendrocyte development are inevitably linked with demyelinating conditions such as multiple sclerosis (MS), leukodystrophies or spinal cord injury (SCI). Chronic loss of myelin, subsequently leading to neurodegeneration, is the ultimate cause of severe and permanent disability. Thus, fast restoration of myelin (remyelination) is essential for circumventing demyelination-caused pathologies.

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Accumulating evidence suggests that inflammatory mediators secreted by activated resident or infiltrated innate immune cells have a significant impact on the pathogenesis of neurodegenerative diseases. This may imply that patients affected by a neurodegenerative disease may benefit from treatment with selective inhibitors of innate immune activity. Here we review the therapeutic potential of apocynin, an essentially nontoxic phenolic compound isolated from the medicinal plant Jatropha multifida.

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Induced pluripotent stem cells (iPSCs) are promising candidates for the study of disease models as well as for tissue engineering purposes. Part of a strategy to develop safe reprogramming technique is reducing the number of exogenous reprogramming factors. Some cells types are more prone to reprogramming than others.

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Cell replacement therapy aiming at the compensation of lost oligodendrocytes and restoration of myelination in acquired or congenital demyelination disorders has gained considerable interest since the discovery of induced pluripotent stem cells (iPSCs). Patient-derived iPSCs provide an inexhaustible source for transplantable autologous oligodendrocyte precursors (OPCs). The first transplantation studies in animal models for demyelination with iPSC-derived OPCs demonstrated their survival and remyelinating capacity, but also revealed their limited migration capacity.

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Unlabelled: The experimental autoimmune encephalomyelitis model is a model of multiple sclerosis that closely mimics the disease characteristics in humans. The main hallmarks of multiple sclerosis are neuroinflammation (microglia activation, monocyte invasion, and T-cell infiltration) and demyelination. PET imaging may be a useful noninvasive technique for monitoring disease progression and drug treatment efficacy in vivo.

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Positron emission tomography (PET) is a non-invasive technique for quantitative imaging of biochemical and physiological processes in animals and humans. PET uses probes labeled with a radioactive isotope, called PET tracers, which can bind to or be converted by a specific biological target and thus can be applied to detect and monitor different aspects of diseases. The number of applications of PET imaging in multiple sclerosis is still limited.

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Induced pluripotent stem cells (iPSCs) hold great promise for in vitro generation of disease-relevant cell types, such as mesodiencephalic dopaminergic (mdDA) neurons involved in Parkinson's disease. Although iPSC-derived midbrain DA neurons have been generated, detailed genetic and epigenetic characterizations of such neurons are lacking. The goal of this study was to examine the authenticity of iPSC-derived DA neurons obtained by established protocols.

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Background: Injection of lysolecithin in the central nervous system results in demyelination accompanied by local activation of microglia and recruitment of monocytes. Positron-emission tomography (PET) imaging, using specific tracers, may be an adequate technique to monitor these events in vivo and therefore may become a tool for monitoring disease progression in multiple sclerosis (MS) patients.

Objectives: The objective of this paper is to evaluate the potential of PET imaging in monitoring local lesions, using [(11)C]MeDAS, [(11)C]PK11195 and [(18)F]FDG as PET tracers for myelin density, microglia activation and glucose metabolism, respectively.

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Purpose: In this study, we compared the ability of [(11)C]CIC, [(11)C]MeDAS and [(11)C]PIB to reveal temporal changes in myelin content in focal lesions in the lysolecithin rat model of multiple sclerosis. Pharmacokinetic modelling was performed to determine the best method to quantify tracer uptake.

Methods: Sprague-Dawley rats were stereotactically injected with either 1 % lysolecithin or saline into the corpus callosum and striatum of the right brain hemisphere.

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Multiple Sclerosis (MS) is a neurodegenerative disease characterized by demyelinated lesions. PET imaging using specific myelin radioligands might solve the lack of a specific imaging tool for diagnosing and monitoring demyelination and remyelination in MS patients. In recent years, a few tracers have been developed for in vivo PET imaging of myelin, but they have not been fully evaluated yet.

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Background: The polycomb group protein Ezh2 is an epigenetic repressor of transcription originally found to prevent untimely differentiation of pluripotent embryonic stem cells. We previously demonstrated that Ezh2 is also expressed in multipotent neural stem cells (NSCs). We showed that Ezh2 expression is downregulated during NSC differentiation into astrocytes or neurons.

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Recent developments in in vitro disease modeling and regenerative medicine have placed induced pluripotent stem cells (iPSCs) in the center of attention as a unique source to study Parkinson's disease. After only 5 years of intensive research, human iPSCs can be generated without viral integration and under xeno-free conditions. This, combined with increasingly sophisticated methods to differentiate iPSCs into functional dopaminergic (DA) neurons, led us to recapitulate the most important findings concerning the use of iPSC technology as a prospective tool to treat symptoms of Parkinson's disease as well as to obtain insight in disease related cell pathogenesis.

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In multiple sclerosis (MS), a chronic inflammatory relapsing demyelinating disease, failure to control or repair damage leads to progressive neurological dysfunction and neurodegeneration. Implantation of neural stem cells (NSCs) has been shown to promote repair and functional recovery in the acute experimental autoimmune encephalomyelitis (EAE) animal model for MS; the major therapeutic mechanism of these NSCs appeared to be immune regulation. In the present study, we examined the efficacy of intraventricularly injected NSCs in chronic relapsing experimental autoimmune encephalomyelitis (CREAE), the animal disease model that is widely accepted to mimic most closely recurrent inflammatory demyelination lesions as observed in relapsing-remitting MS.

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