Publications of Thierry GRISAR
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See detailSubtle brain developmental abnormalities in the pathogenesis of juvenile myoclonic epilepsy
Gilsoul, Maxime ULiege; Grisar, Thierry ULiege; Delgado-Escueta, Antonio V et al

in Frontiers in Cellular Neuroscience (2019), 13

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See detailImportin-8 Modulates Division of Apical Progenitors, Dendritogenesis and Tangential Migration During Development of Mouse Cortex.
Nganou, Gerry; Gomes Da Silva, Carla ULiege; Gladwyn-Ng, Ivan ULiege et al

in Frontiers in Molecular Neuroscience (2018), 11

The building of the brain is a multistep process that requires the coordinate expression of thousands of genes and an intense nucleocytoplasmic transport of RNA and proteins. This transport is mediated by ... [more ▼]

The building of the brain is a multistep process that requires the coordinate expression of thousands of genes and an intense nucleocytoplasmic transport of RNA and proteins. This transport is mediated by karyopherins that comprise importins and exportins. Here, we investigated the role of the ss-importin, importin-8 (IPO8) during mouse cerebral corticogenesis as several of its cargoes have been shown to be essential during this process. First, we showed that Ipo8 mRNA is expressed in mouse brain at various embryonic ages with a clear signal in the sub-ventricular/ventricular zone (SVZ/VZ), the cerebral cortical plate (CP) and the ganglionic eminences. We found that acute knockdown of IPO8 in cortical progenitors reduced both their proliferation and cell cycle exit leading to the increase in apical progenitor pool without influencing the number of basal progenitors (BPs). Projection neurons ultimately reached their appropriate cerebral cortical layer, but their dendritogenesis was specifically affected, resulting in neurons with reduced dendrite complexity. IPO8 knockdown also slowed the migration of cortical interneurons. Together, our data demonstrate that IPO8 contribute to the coordination of several critical steps of cerebral cortex development. These results suggest that the impairment of IPO8 function might be associated with some diseases of neuronal migration defects. [less ▲]

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See detailEFHC1 variants in juvenile myoclonic epilepsy: reanalysis according to NHGRI and ACMG guidelines for assigning disease causality
Bailey, JN; Patterson, C; de Nijs, L et al

in Genetics in Medicine (2017), 19

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See detailMyoclonin1/EFHC1 in cell division, neuroblast migration, synapse/dendrite formation in juvenile myoclonic epilepsy
Grisar, Thierry ULiege; Lakaye, Bernard ULiege; de Nijs, Laurence ULiege et al

in Noebels, JL; Avoli, M; Rogawski, MA (Eds.) et al Jasper's Basic Mechanisms of the Epilepsies, 4th edition (2012)

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See detailThiamine Status in Humans and Content of Phosphorylated Thiamine Derivatives in Biopsies and Cultured Cells
Gangolf, Marjorie ULiege; Czerniecki, Jan; Radermecker, Marc ULiege et al

in PLoS ONE (2010), 5(10), 13616

Background Thiamine (vitamin B1) is an essential molecule for all life forms because thiamine diphosphate (ThDP) is an indispensable cofactor for oxidative energy metabolism. The less abundant thiamine ... [more ▼]

Background Thiamine (vitamin B1) is an essential molecule for all life forms because thiamine diphosphate (ThDP) is an indispensable cofactor for oxidative energy metabolism. The less abundant thiamine monophosphate (ThMP), thiamine triphosphate (ThTP) and adenosine thiamine triphosphate (AThTP), present in many organisms, may have still unidentified physiological functions. Diseases linked to thiamine deficiency (polyneuritis, Wernicke-Korsakoff syndrome) remain frequent among alcohol abusers and other risk populations. This is the first comprehensive study on the distribution of thiamine derivatives in human biopsies, body fluids and cell lines. Methodology and Principal Findings Thiamine derivatives were determined by HPLC. In human tissues, the total thiamine content is lower than in other animal species. ThDP is the major thiamine compound and tissue levels decrease at high age. In semen, ThDP content correlates with the concentration of spermatozoa but not with their motility. The proportion of ThTP is higher in humans than in rodents, probably because of a lower 25-kDa ThTPase activity. The expression and activity of this enzyme seems to correlate with the degree of cell differentiation. ThTP was present in nearly all brain and muscle samples and in ~60% of other tissue samples, in particular fetal tissue and cultured cells. A low ([ThTP]+[ThMP])/([Thiamine]+[ThMP]) ratio was found in cardiovascular tissues of patients with cardiac insufficiency. AThTP was detected only sporadically in adult tissues but was found more consistently in fetal tissues and cell lines. Conclusions and Significance The high sensitivity of humans to thiamine deficiency is probably linked to low circulating thiamine concentrations and low ThDP tissue contents. ThTP levels are relatively high in many human tissues, as a result of low expression of the 25-kDa ThTPase. Another novel finding is the presence of ThTP and AThTP in poorly differentiated fast-growing cells, suggesting a hitherto unsuspected link between these compounds and cell division or differentiation. [less ▲]

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See detailDistribution of EFHC1 or myoclonin 1 in mouse neural structures
Leon, Christine ULiege; de Nijs, Laurence ULiege; Chanas, Grazyna et al

in Epilepsy Research (2010), 88

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See detailThe epileptic syndromes with continuous spikes and waves during slow sleep: definition and management guidelines.
Van Bogaert, P.; Aeby, A.; De Borchgrave, V. et al

in Acta Neurologica Belgica (2006), 106(2), 52-60

The authors propose to define the epileptic syndromes with continuous spikes and waves during slow sleep (CSWS) as a cognitive or behavioral impairment acquired during childhood, associated with a strong ... [more ▼]

The authors propose to define the epileptic syndromes with continuous spikes and waves during slow sleep (CSWS) as a cognitive or behavioral impairment acquired during childhood, associated with a strong activation of the interictal epileptiform discharges during NREM sleep--whatever focal or generalized--and not related to another factor than the presence of CSWS. The type of syndrome will be defined according to the neurological and neuropsychological deficit. These syndromes have to be classified among the localization-related epileptic syndromes. Some cases are idiopathic and others are symptomatic. Guidelines for work-up and treatment are proposed. [less ▲]

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See detailHuman immune cells express ppMCH mRNA and functional MCHR1 receptor
Verlaet, Myriam ULiege; Adamantidis, Antoine ULiege; Coumans, Bernard ULiege et al

in FEBS Letters (2002), 527(1-3), 205-210

Melanin-concentrating hormone (MCH) is highly expressed in the brain and modulates feeding behavior. It is also expressed in some peripheral tissues where its role remains unknown. We have investigated ... [more ▼]

Melanin-concentrating hormone (MCH) is highly expressed in the brain and modulates feeding behavior. It is also expressed in some peripheral tissues where its role remains unknown. We have investigated MCH function in human and mouse immune cells. RT-PCR analysis revealed a low expression of prepro-MCH and MCH receptor 1 (MCHR1) but not of MCHR2 transcript in tissular and peripheral blood immune cells. FACS and in vitro assay studies demonstrated that MCHR1 receptor expression on most cell types can trigger, in the presence of MCH, cAMP synthesis and calcium mobilization in peripheral blood mononuclear cells (PBMCs). Moreover, MCH treatment decreases the CD3-stimulated PBMC proliferation in vitro. Accordingly, our data indicate for the first time that MCH and MCHR1 may exert immunomodulatory functions. (C) 2002 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved. [less ▲]

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See detailAdenylate kinase 1 knockout mice have normal thiamine triphosphate levels
Makarchikov, Alexander F; Wins, Pierre; Janssen, E. et al

in BBA Molecular Cell Research (2002), 1592(2), 117-121

Thiamine triphosphate (ThTP) is found at low concentrations in most animal tissues and it may act as a phosphate donor for the phosphorylation of proteins, suggesting a potential role in cell signaling ... [more ▼]

Thiamine triphosphate (ThTP) is found at low concentrations in most animal tissues and it may act as a phosphate donor for the phosphorylation of proteins, suggesting a potential role in cell signaling. Two mechanisms have been proposed for the enzymatic synthesis of ThTP. A thiamine diphosphate (ThDP) kinase (ThDP + ATP double left right arrow ThTP + ADP) has been purified from brewer's yeast and shown to exist in rat liver. However, other data suggest that, at least in skeletal muscle, adenylate kinase I (AK1) is responsible for ThTP synthesis. In this study, we show that AK1 knockout mice have normal ThTP levels in skeletal muscle, heart, brain, liver and kidney, demonstrating that AK1 is not responsible for ThTP synthesis in those tissues. We predict that the high ThTP content of particular tissues like the Electrophorus electricus electric organ, or pig and chicken skeletal muscle is more tightly correlated with high ThDP kinase activity or low soluble ThTPase activity than with non-stringent substrate specificity and high activity of adenylate kinase. (C) 2002 Elsevier Science B.V All rights reserved. [less ▲]

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See detailHousekeeping Genes as Internal Standards: Use and Limits
Thellin, Olivier ULiege; Zorzi, Willy ULiege; Lakaye, Bernard ULiege et al

in Journal of Biotechnology (1999), 75(2-3), 291-5

Quantitative studies are commonly realised in the biomedical research to compare RNA expression in different experimental or clinical conditions. These quantifications are performed through their ... [more ▼]

Quantitative studies are commonly realised in the biomedical research to compare RNA expression in different experimental or clinical conditions. These quantifications are performed through their comparison to the expression of the housekeeping gene transcripts like glyceraldehyde-3-phosphate dehydrogenase (G3PDH), albumin, actins, tubulins, cyclophilin, hypoxantine phsophoribosyltransferase (HRPT), L32. 28S, and 18S rRNAs are also used as internal standards. In this paper, it is recalled that the commonly used internal standards can quantitatively vary in response to various factors. Possible variations are illustrated using three experimental examples. Preferred types of internal standards are then proposed for each of these samples and thereafter the general procedure concerning the choice of an internal standard and the way to manage its uses are discussed. [less ▲]

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See detailThiamine Deficiency--Induced Partial Necrosis and Mitochondrial Uncoupling in Neuroblastoma Cells Are Rapidly Reversed by Addition of Thiamine
Bettendorff, Lucien ULiege; Sluse, Francis ULiege; Goessens, Guy ULiege et al

in Journal of Neurochemistry (1995), 65(5), 2178-2184

Culture of neuroblastoma cells in a medium of low-thiamine concentration (6 nM) and in the presence of the transport inhibitor amprolium leads to the appearance of overt signs of necrosis; i.e., the ... [more ▼]

Culture of neuroblastoma cells in a medium of low-thiamine concentration (6 nM) and in the presence of the transport inhibitor amprolium leads to the appearance of overt signs of necrosis; i.e., the chromatin condenses in dark patches, the oxygen consumption decreases, mitochondria are uncoupled, and their cristae are disorganized. Glutamate formed from glutamine is no longer oxidized and accumulates, suggesting that the thiamine diphosphate-dependent alpha-ketoglutarate dehydrogenase activity is impaired. When thiamine (10 microM) is added to the cells, the O2 consumption increases, respiratory control is restored, and normal cell and mitochondrial morphology is recovered within 1 h. Succinate, which is oxidized via the thiamine diphosphate-independent succinate dehydrogenase, is also able to restore a normal O2 consumption (with respiratory control) in digitonin-permeabilized thiamine-deficient cells. Our results therefore suggest that the slowing of the citric acid cycle is the main cause of the biochemical lesion induced by thiamine deficiency as observed in Wernicke's encephalopathy. [less ▲]

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