25 results on '"François, Marie"'
Search Results
2. Synapsin associates with cyclophilin B in an ATP- and cyclosporin A-dependent manner
- Author
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Lane-Guermonprez, Lydie, Morot-Gaudry-Talarmain, Yvette, Meunier, François-Marie, OʼRegan, Seana, Onofri, Franco, Le Caer, Jean-Pierre, and Benfenati, Fabio
- Published
- 2005
3. The neuronal choline transporter CHT1 is regulated by immunosuppressor-sensitive pathways
- Author
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Guermonprez, Lydie, OʼRegan, Seana, Meunier, François-Marie, and Morot-Gaudry-Talarmain, Yvette
- Published
- 2002
4. Detection of choline transporter-like 1 protein CTL1 in neuroblastoma × glioma cells and in the CNS, and its role in choline uptake
- Author
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Rosamund Dove, Seana O'Regan, Vladimír Doležal, Joanna Prentice, V. Lisa, François-Marie Meunier, Jia Newcombe, and Eva Machová
- Subjects
0303 health sciences ,Cell growth ,Biology ,Biochemistry ,Choline acetyltransferase ,Carnitine transport ,Choline transporter ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,0302 clinical medicine ,chemistry ,medicine ,Choline ,Cholinergic ,Choline transport ,030217 neurology & neurosurgery ,Acetylcholine ,030304 developmental biology ,medicine.drug - Abstract
Choline is an essential nutrient necessary for synthesis of membrane phospholipids, cell signalling molecules and acetylcholine. The aim of this study was to detect and characterize the choline transporter-like 1 (CTL1/SLC44A1) protein in CNS tissues and the hybrid neuroblastoma x glioma cell line NG108-15, which synthesizes acetylcholine and has high affinity choline transport but does not express the cholinergic high affinity choline transporter 1. The presence of CTL1 protein in NG108-15 cells was confirmed using our antibody G103 which recognizes the C-terminal domain of human CTL1. Three different cognate small interfering RNAs were used to decrease CTL1 mRNA in NG108-15 cells, causing lowered CTL1 protein expression, choline uptake and cell growth. None of the small interfering RNAs influenced carnitine transport, demonstrating the absence of major non-specific effects. In parental C6 cells knockdown of CTL1 also reduced high affinity choline transport. Our results support the concept that CTL1 protein is necessary for the high affinity choline transport which supplies choline for cell growth. The presence of CTL1 protein in rat and human CNS regions, where it is found in neuronal, glial and endothelial cells, suggests that malfunction of this transporter could have important implications in nervous system development and repair following injury, and in neurodegenerative diseases.
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- 2009
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5. Molecular characterization of the family of choline transporter-like proteins and their splice variants
- Author
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Martial Ruat, Seana O'Regan, François-Marie Meunier, and Elisabeth Traiffort
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biology ,Alternative splicing ,Transfection ,Biochemistry ,Oligodendrocyte ,Myelin basic protein ,Cell biology ,Choline transporter ,Cellular and Molecular Neuroscience ,Myelin ,medicine.anatomical_structure ,medicine ,biology.protein ,Neuroglia ,Choline transport ,Neuroscience - Abstract
We show here that the choline transporter-like (CTL) family is more extensive than initially described with five genes in humans and complex alternative splicing. In adult rat tissues, CTL2-4 mRNAs are mainly detected in peripheral tissues, while CTL1 is widely expressed throughout the nervous system. During rat post-natal development, CTL1 is expressed in several subpopulations of neurones and in the white matter, where its spatio-temporal distribution profile recalls that of myelin basic protein, an oligodendrocyte marker. We identified two major rat splice variants of CTL1 (CTL1a and CTL1b) differing in their carboxy-terminal tails with both able to increase choline transport after transfection in neuroblastoma cells. In the developing brain, CTL1a is expressed in both neurones and oligodendroglial cells, whereas CTL1b is restricted to oligodendroglial cells. These findings suggest specific roles for CTL1 splice variants in both neuronal and oligodendrocyte physiology.
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- 2005
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6. Evoked Acetylcholine Release Expressed in Neuroblastoma Cells by Transfection of Mediatophore cDNA
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M. Synguelakis, Françoise Loctin, B. Lesbats, L Eder-Colli, P Corrèges, J Falk-Vairant, N Salem, François-Marie Meunier, Yves Dunant, and Maurice Israël
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DNA, Complementary ,Xenopus ,chemistry.chemical_element ,Nerve Tissue Proteins ,Stimulation ,Biology ,Calcium ,Torpedo ,Transfection ,Biochemistry ,Mice ,Neuroblastoma ,Cellular and Molecular Neuroscience ,Tumor Cells, Cultured ,medicine ,Animals ,Myocyte ,Glioma ,Molecular biology ,Acetylcholine ,Electric Stimulation ,Rats ,Cell biology ,Electrophysiology ,medicine.anatomical_structure ,chemistry ,Cell culture ,Neuron ,Neurosecretion ,medicine.drug - Abstract
Transmitter release was elicited in two ways from cultured cells filled with acetylcholine: (a) in a biochemical assay by successive addition of a calcium ionophore and calcium and (b) electrophysiologically, by electrical stimulation of individual cells and real-time recording with an embryonic Xenopus myocyte. Glioma C6-Bu-1 cells were found to be competent for Ca(2+)-dependent and quantal release. In contrast, no release could be elicited from mouse neuroblastoma N18TG-2 cells. However, acetylcholine release could be restored when N18TG-2 cells were transfected with a plasmid coding for mediatophore. Mediatophore is a protein of nerve terminal membranes purified from the Torpedo electric organ on the basis of its acetylcholine-releasing capacity. The transfected N18TG-2 cells expressed Torpedo mediatophore in their plasma membrane. In response to an electrical stimulus, they generated in the myocyte evoked currents that were curare sensitive and calcium dependent and displayed, discrete amplitude levels, like in naturally occurring synapses.
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- 2002
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7. A Ewing's Sarcoma Cell Line Showing Some, but Not All, of the Traits of a Cholinergic Neuron
- Author
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Seana O'Regan, François-Marie Meunier, Sheela Vyas, and Marie-Françoise Diebler
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Adult ,Male ,Vesamicol ,Tyrosine 3-Monooxygenase ,Proteolipids ,Nerve Tissue Proteins ,Sarcoma, Ewing ,Biology ,Tritium ,Biochemistry ,Synaptic vesicle ,Choline ,Choline O-Acetyltransferase ,Synaptotagmins ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,Piperidines ,Acetylcholine transport ,Tumor Cells, Cultured ,medicine ,Humans ,RNA, Messenger ,Cholinergic neuron ,Neurotransmitter ,Neurons ,Membrane Glycoproteins ,Calcium-Binding Proteins ,Choline acetyltransferase ,Acetylcholine ,Cell biology ,Cholinergic Fibers ,chemistry ,Neuromuscular Depolarizing Agents ,Synaptotagmin I ,Cholinergic ,medicine.drug - Abstract
The Ewing's sarcoma cell line ICB 112 was examined in detail for a cholinergic phenotype. Choline acetyltransferase activity (12.3 +/- 2.9 nmol/h/mg of protein) was associated with the presence of multiple mRNA species labeled with a human choline acetyltransferase riboprobe. Choline was taken up by the cells by a high-affinity, hemicholinium-3-sensitive transporter that was partially inhibited when lithium replaced sodium in the incubation medium; the choline taken up was quickly incorporated into both acetylcholine and phosphorylcholine. High-affinity binding sites for vesamicol, an inhibitor of vesicular acetylcholine transport, were also present. The mRNAs for synaptotagmin (p65) and the 15-kDa proteolipid were readily detected and were identical in size to those observed in cholinergic regions of the human brain. Cumulative acetylcholine efflux was increased by raising the extracellular potassium level or the addition of a calcium ionophore, but the time course of stimulated efflux was slow and persistent. These results show that this morphologically undifferentiated cell line is capable of acetylcholine synthesis and expresses markers for synaptic vesicles as well as proteins implicated in calcium-dependent release but lacks an organized release mechanism.
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- 2002
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8. The neuronal choline transporter CHT1 is regulated by immunosuppressor-sensitive pathways
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Seana O'Regan, François-Marie Meunier, Lydie Guermonprez, and Yvette Morot-Gaudry-Talarmain
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Biology ,Biochemistry ,Calcineurin ,Choline transporter ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,FKBP ,chemistry ,Hemicholinium-3 ,Cyclosporin a ,polycyclic compounds ,Choline ,Cholinergic ,Choline transport - Abstract
The immunosuppressor cyclosporin A inhibits the peptidyl-prolyl-cis/trans-isomerase activity of cyclophilins and the resulting complex inhibits the phosphatase activity of calcineurin. Both enzymes were detected in peripheral nerve endings isolated from the electric organ of Torpedo and shown to be affected by 10 micro m cyclosporin A. Among the cholinergic properties studied, choline uptake was specifically inhibited by cyclosporin A to a maximum of 40%. Cyclosporin A decreased the rate of choline transport but not the binding of the non-transportable choline analogue hemicholinium-3, indicating that the number of membrane transporters was not affected. Through the use of two other immunosuppressors, FK506, which also inhibits calcineurin, and rapamycin, which does not, two different mechanisms of choline uptake inhibition were uncovered. FK506 inhibited the rate of choline transport, whereas rapamycin diminished the affinity for choline. The Torpedo homologue of the high affinity choline transporter CHT1 was cloned and its activity was reconstituted in Xenopus oocytes. Choline uptake by oocytes expressing tCHT1 was inhibited by all three immunosuppressors and also by microinjection of the specific calcineurin autoinhibitory domain A457-481, indicating that the phosphatase calcineurin regulates CHT1 activity and could be the common target of cyclosporin and FK506. Rapamycin, which changed the affinity of the transporter, may have acted through an immunophilin on the isomerization of critical prolines that are found in the tCHT1 sequence.
- Published
- 2002
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9. Cellular resistance to Evans blue toxicity involves an up-regulation of a phosphate transporter implicated in vesicular glutamate storage
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Maurice Israël, Monique Tomasi, François-Marie Meunier, and Sébastien Bostel
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Glutamate receptor ,Transporter ,Biology ,Biochemistry ,Synaptic vesicle ,Vesicular transport protein ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,chemistry ,Cell culture ,Northern blot ,Intracellular ,Evans Blue - Abstract
It has recently been suggested that the brain-specific Na+-dependent phosphate inorganic co-transporter (BNPI) is able to support glutamate transport and storage in synaptic vesicles. A procedure for measuring the vesicular pool of glutamate is described and was used to select cell lines according to their glutamate storage capacity. Two cell lines were selected: C6BU-1, with a large intracellular glutamate storage capacity, and NG108-15, devoid of it. Their contents in BNPI mRNA were compared by RT-PCR. We found that both cell lines had BNPI, but in addition C6BU-1 alone expresses the other isoform, DNPI. We also carried out a clonal selection of NG108-15 cells in the presence of the dye Evans blue, a competitive inhibitor of vesicular glutamate transport, very toxic for cells in culture. It was assumed that only those that sequester and eliminate the drug by overexpressing a vesicular glutamate transporter would survive. We found that the NG108-15 clones resistant to Evans blue had an increased storage capacity for glutamate. These cells also up-regulated the BNPI isoform of the phosphate transporter as shown by RT-PCR and northern blot.
- Published
- 2001
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10. The neuronal choline transporter CHT1 is regulated by immunosuppressor-sensitive pathways
- Author
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Lydie, Guermonprez, Seana, O'Regan, François-Marie, Meunier, and Yvette, Morot-Gaudry-Talarmain
- Subjects
Models, Molecular ,Microinjections ,Calcineurin Inhibitors ,Molecular Sequence Data ,Torpedo ,Transfection ,Binding, Competitive ,Tacrolimus ,Choline ,Xenopus laevis ,Animals ,Cloning, Molecular ,Enzyme Inhibitors ,Nerve Endings ,Sirolimus ,Electric Organ ,Sequence Homology, Amino Acid ,Calcineurin ,Membrane Transport Proteins ,Biological Transport ,Hemicholinium 3 ,Peptidylprolyl Isomerase ,Cyclosporine ,Oocytes ,Immunosuppressive Agents ,Synaptosomes - Abstract
The immunosuppressor cyclosporin A inhibits the peptidyl-prolyl-cis/trans-isomerase activity of cyclophilins and the resulting complex inhibits the phosphatase activity of calcineurin. Both enzymes were detected in peripheral nerve endings isolated from the electric organ of Torpedo and shown to be affected by 10 micro m cyclosporin A. Among the cholinergic properties studied, choline uptake was specifically inhibited by cyclosporin A to a maximum of 40%. Cyclosporin A decreased the rate of choline transport but not the binding of the non-transportable choline analogue hemicholinium-3, indicating that the number of membrane transporters was not affected. Through the use of two other immunosuppressors, FK506, which also inhibits calcineurin, and rapamycin, which does not, two different mechanisms of choline uptake inhibition were uncovered. FK506 inhibited the rate of choline transport, whereas rapamycin diminished the affinity for choline. The Torpedo homologue of the high affinity choline transporter CHT1 was cloned and its activity was reconstituted in Xenopus oocytes. Choline uptake by oocytes expressing tCHT1 was inhibited by all three immunosuppressors and also by microinjection of the specific calcineurin autoinhibitory domain A457-481, indicating that the phosphatase calcineurin regulates CHT1 activity and could be the common target of cyclosporin and FK506. Rapamycin, which changed the affinity of the transporter, may have acted through an immunophilin on the isomerization of critical prolines that are found in the tCHT1 sequence.
- Published
- 2002
11. Evoked acetylcholine release by immortalized brain endothelial cells genetically modified to express choline acetyltransferase and/or the vesicular acetylcholine transporter
- Author
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L. Prado de Carvalho, Michel Malo, François-Marie Meunier, Yves Dunant, Marie-Françoise Diebler, Pierre-Olivier Couraud, Monique Tomasi, Jean-Léon Tchelingerian, Maurice Israël, Alain Bloc, and Jacques Stinnakre
- Subjects
Patch-Clamp Techniques ,Vesicular Acetylcholine Transport Proteins ,Vesicular Transport Proteins ,Stimulation ,Biology ,Transfection ,Biochemistry ,Choline O-Acetyltransferase ,Membrane Potentials ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,Xenopus laevis ,Piperidines ,Vesicular acetylcholine transporter ,medicine ,Animals ,Neurotransmitter ,Muscle, Skeletal ,Cells, Cultured ,Cell Line, Transformed ,Microcirculation ,Membrane Transport Proteins ,Depolarization ,Choline acetyltransferase ,Acetylcholine ,Recombinant Proteins ,Cell biology ,Rats ,chemistry ,Cerebrovascular Circulation ,Neuromuscular Depolarizing Agents ,Cholinergic ,Endothelium, Vascular ,Esterase inhibitor ,Carrier Proteins ,medicine.drug - Abstract
Immortalized rat brain endothelial RBE4 cells do not express choline acetyltransferase (ChAT), but they do express an endogenous machinery that enables them to release specifically acetylcholine (ACh) on calcium entry when they have been passively loaded with the neurotransmitter. Indeed, we have previously reported that these cells do not release glutamate or GABA after loading with these transmitters. The present study was set up to engineer stable cell lines producing ACh by transfecting them with an expression vector construct containing the rat ChAT. ChAT transfectants expressed a high level of ChAT activity and accumulated endogenous ACh. We examined evoked ACh release from RBE4 cells using two parallel approaches. First, Ca2+-dependent ACh release induced by a calcium ionophore was followed with a chemiluminescent procedure. We showed that ChAT-transfected cells released the transmitter they had synthesized and accumulated in the presence of an esterase inhibitor. Second, ACh released on an electrical depolarization was detected in real time by a whole-cell voltageclamped Xenopus myocyte in contact with the cell. Whether cells synthesized ACh or whether they were passively loaded with ACh electrical stimulation elicited the release of ACh quanta detected as inward synaptic-like currents in the myocyte. Repetitive stimulation elicited a continuous train of responses of decreasing amplitudes, with rare failures. Amplitude analysis showed that the currents peaked at preferential levels, as if they were multiples of an elementary component. Furthermore, we selected an RBE4 transgenic clone exhibiting a high level of ChAT activity to introduce the Torpedo vesicular ACh transporter (VAChT) gene. However, as the expression of ChAT was inactivated in stable VAChT transfectants, the potential influence of VAChT on evoked ACh release could only be studied on cells passively loaded with ACh. VAChT expression modified the pattern of ACh delivery on repetitive electrical stimulation. Stimulation trains evoked several groups of responses interupted by many failures. The total amount of released ACh and the mean quantal size were not modified. As brain endothelial cells are known as suitable cellular vectors for delivering gene products to the brain, the present results suggest that RBE4 cells genetically modified to produce ACh and intrinsically able to support evoked ACh release may provide a useful tool for improving altered cholinergic function in the CNS.
- Published
- 1999
12. Two-site immunoradiometric assay of chicken acetylcholinesterase: active and inactive molecular forms in brain and muscle
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Jean Massoulié, François-Marie Vallette, Suzanne Bon, Jacques Grassi, Jerry Eichler, and Jean-Marc Chatel
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medicine.drug_class ,Chick Embryo ,Monoclonal antibody ,Biochemistry ,Cellular and Molecular Neuroscience ,Enzyme activator ,chemistry.chemical_compound ,Species Specificity ,Antibody Specificity ,medicine ,Centrifugation, Density Gradient ,Animals ,Butyrylcholinesterase ,Micelles ,Immunoradiometric assay ,biology ,Chemistry ,Muscles ,Antibodies, Monoclonal ,Brain ,Trypsin ,Molecular biology ,Acetylcholinesterase ,Enzyme Activation ,biology.protein ,Protein quaternary structure ,Immunoradiometric Assay ,Antibody ,medicine.drug - Abstract
Several monoclonal antibodies were raised against chicken acetylcholinesterase (AChE; EC 3.1.1.7). Some of these antibodies react with quail AChE but not with AChEs from nonavian vertebrates or invertebrates and not with butyrylcholinesterase. They may be classified in several mutually compatible groups, i.e., that can bind simultaneously to the monomeric form of AChE. Most antibodies recognize a peptidic domain that does not exist in mammalian AChE and that may be digested by trypsin without loss of activity or dissociation of quaternary structure. The only exception is the antibody C-131, which is conformation dependent and preferentially recognizes active AChE. We have set up two-site immunoradiometric assays, using an immobilized capture antibody, C-6 or C-131, and a radiolabeled antibody, 125I-C-54. The C-6/C-54 assay quantifies the totality of inactive and active AChE subunits: It detects 10(-3) Ellman unit (approximately 40 pg of protein) and yields a linear response up to at least 25 10(-3) Ellman units. An analysis of gradient fractions, using C-6/C-54 and C-131/C-54 assays as well as activity determination, shows that the A12 and G4 forms are exclusively composed of active subunits, whereas inactive molecules cosediment with the active G2 and G1 forms. Both active and inactive G2 and G1 forms are amphiphilic, as indicated by the influence of detergents on their sedimentation coefficients and Stokes radii. In brain, the proportion of inactive forms decreases from 40% at embryonic day 11 (E11) to 20% at birth [day 1 (D1)]. In muscle, we observed no inactive AChE at E11 and a small proportion of inactive G1 at D1.(ABSTRACT TRUNCATED AT 250 WORDS)
- Published
- 1994
13. Evolution of acetylcholinesterase transcripts and molecular forms during development in the central nervous system of the quail
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Jean Massoulié, Mireille Fauquet, Alain Anselmet, Jean-Marc Chatel, François-Marie Vallette, and Yves Maulet
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Nervous system ,Central Nervous System ,Cerebellum ,Aging ,DNA, Complementary ,Protein subunit ,Central nervous system ,Molecular Sequence Data ,Molecular Conformation ,Biochemistry ,Quail ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,Embryonic and Fetal Development ,Fetus ,biology.animal ,Gene expression ,medicine ,Animals ,Amino Acid Sequence ,RNA, Messenger ,Messenger RNA ,biology ,Base Sequence ,Acetylcholinesterase ,Cell biology ,medicine.anatomical_structure ,chemistry ,Animals, Newborn ,Molecular Probes - Abstract
We studied the expression of acetylcholinesterase (AChE) in the nervous system (cerebellum, optic lobes, and neuroretina) of the quail at different stages of development, from embryonic day 10 (E10) to the adult. Analyzing AChE mRNAs and AChE molecular forms, we observed variations in the following: (a) production of multiplemRNA species (4.5 kb, 5.3 kb, and 6 kb); (b) translation and/or stability of the AChE protein; (c) production of active and inactive AChE molecules; (d) production of amphiphilic and nonamphiphilic AChE forms; and (e) proportions of tetrameric G4, dimeric G2, and monomeric G1 forms. The large transcripts present distinct temporal patterns and disappear in the adult, which possesses only the 4.5-kb mRNA; these changes are unlikely to be related to those observed for the AChE protein, because all transcripts seem to encode the same catalytic subunit (type T). In addition, the levels of mRNA and AChE are not correlated in the three regions, especially at the adult stage. The proportion of inactive AChE was found to be markedly higher at the hatching period (E16) than at earlier stages (E10 and E13) or in the adult. The G4 form is pre-dominant already at E10, and in the adult its proportion reaches 80% of the activity in the cerebellum and optic lobes, and 65–70% in the neuroretina. This form is largely nonamhiphilic in embryonic tissues, but it becomes progressively more amphiphilic with development. Thus, the different processing and maturation steps appear to be regulated in an independent manner and potentially correspond to physiologically adaptative mechanisms.
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- 1994
14. Regulation of the expression of acetylcholinesterase by muscular activity in avian primary cultures
- Author
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François-Marie Vallett and Jean Massoulié
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medicine.medical_specialty ,Molecular Conformation ,Tetrodotoxin ,Biology ,Biochemistry ,Quail ,Potassium Chloride ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,Internal medicine ,medicine ,Myocyte ,Animals ,Receptors, Cholinergic ,Creatine Kinase ,Cells, Cultured ,Veratridine ,Myogenesis ,Muscles ,Depolarization ,Cell Differentiation ,Acetylcholinesterase ,Endocrinology ,chemistry ,Cell culture ,medicine.symptom ,Chickens ,Muscle contraction - Abstract
Primary cultures of avian muscle cells express both globular and asymmetric molecular forms of acetylcholinesterase (AChE) when grown in a simple defined culture medium. Under these conditions, we analyzed the role of various agents interfering with muscular activity: tetrodotoxin (TTX) and veratridine, as well as a depolarizing concentration of KCl. These treatments caused the complete cessation of contractions in mature myotubes. We observed no influence on cellular AChE activity. The paralyzing treatments induced different effects on AChE secretion: TTX increased the secretion by approximately 25%, whereas KCl and veratridine reduced it by approximately 30%. The proportions of secreted molecular forms (mostly hydrophilic G4 and G2) were not modified significantly. TTX did not affect the pattern of molecular forms of cellular AChE (in particular, the proportion of A forms was not changed). Depolarization by veratridine or KCl induced an increase in the proportion of A forms in mature myotubes by a factor of 2-3. Similar results were obtained with quail myotubes cultured under the same conditions. This study shows that, in avian muscle cultures, the ionic balance across myotube membranes, rather than muscular activity per se, can regulate the level of A forms and the rate of AChE secretion. These results do not exclude the possible involvement of other factors, such as Ca2+ and/or peptidic factors. In addition, taking together our results and data from the literature. we conclude that the expression of AChE molecular forms depends both on the species and on the culture conditions used.
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- 1991
15. A Ewing's Sarcoma Cell Line Showing Some, but Not All, of the Traits of a Cholinergic Neuron
- Author
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O'Regan, Seana, primary, Diebler, Marie-Françoise, additional, Meunier, François-Marie, additional, and Vyas, Sheela, additional
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- 2002
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16. Differential Targeting to the Plasma Membrane of the Torpedo 15‐kDa Proteolipid Expressed in Oocytes
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Leroy, Christine, primary and Meunier, François‐Marie, additional
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- 1995
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17. Two‐Site Immunoradiometric Assay of Chicken Acetylcholinesterase: Active and Inactive Molecular Forms in Brain and Muscle
- Author
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Chatel, Jean‐Marc, primary, Eichler, Jerry, additional, Vallette, François‐Marie, additional, Bon, Suzanne, additional, Massoulié, Jean, additional, and Grassi, Jacques, additional
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- 1994
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18. Detection of choline transporter-like 1 protein CTL1 in neuroblastoma × glioma cells and in the CNS, and its role in choline uptake.
- Author
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Machov&3x00E1;, Eva, O'Regan, Seana, Newcombe, Jia, Meunier, François-Marie, Prentice, Joanna, Dove, Rosamund, Lis, Věra, and Doležal, Vladimír
- Subjects
CHOLINE ,NEUROBLASTOMA ,GLIOMAS ,CANCER cells ,PHOSPHOLIPIDS ,ACETYLCHOLINE - Abstract
Choline is an essential nutrient necessary for synthesis of membrane phospholipids, cell signalling molecules and acetylcholine. The aim of this study was to detect and characterize the choline transporter-like 1 (CTL1/SLC44A1) protein in CNS tissues and the hybrid neuroblastoma × glioma cell line NG108-15, which synthesizes acetylcholine and has high affinity choline transport but does not express the cholinergic high affinity choline transporter 1. The presence of CTL1 protein in NG108-15 cells was confirmed using our antibody G103 which recognizes the C-terminal domain of human CTL1. Three different cognate small interfering RNAs were used to decrease CTL1 mRNA in NG108-15 cells, causing lowered CTL1 protein expression, choline uptake and cell growth. None of the small interfering RNAs influenced carnitine transport, demonstrating the absence of major non-specific effects. In parental C6 cells knockdown of CTL1 also reduced high affinity choline transport. Our results support the concept that CTL1 protein is necessary for the high affinity choline transport which supplies choline for cell growth. The presence of CTL1 protein in rat and human CNS regions, where it is found in neuronal, glial and endothelial cells, suggests that malfunction of this transporter could have important implications in nervous system development and repair following injury, and in neurodegenerative diseases. [ABSTRACT FROM AUTHOR]
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- 2009
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19. Regulation of the Expression of Acetylcholinesterase by Muscular Activity in Avian Primary Cultures
- Author
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Vallett, François-Marie, primary and Massoulié, Jean, additional
- Published
- 1991
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20. Acetylcholinesterase in Cocultures of Rat Myotubes and Spinal Cord Neurons: Effects of Collagenase and cis‐Hydroxyproline on Molecular Forms, Intra‐ and Extracellular Distribution, and Formation of Patches at Neuromuscular Contacts
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Vallette, François‐Marie, primary, De la Porte, Sabine, additional, Koenig, Jeanine, additional, Massoulié, Jean, additional, and Vigny, Marc, additional
- Published
- 1990
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21. Simultaneous Release of Acetylcholine and ATP from Stimulated Cholinergic Synaptosomes.
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Morel, Nicolas and Meunier, François-Marie
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- 1981
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22. A Ewing's Sarcoma Cell Line Showing Some, but Not All, of the Traits of a Cholinergic Neuron.
- Author
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O'Regan, Seana, Diebler, Marie-Françoise, Meunier, François-Marie, and Vyas, Sheela
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- 1995
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23. Retrograde Inhibition of Transmitter Release by ATP
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François-Marie Meunier, R. Manaranche, P. Frachon, B. Lesbats, and Maurice Israël
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Adenosine ,Carbachol ,Stimulation ,Acetates ,Pharmacology ,Inhibitory postsynaptic potential ,Biochemistry ,Cellular and Molecular Neuroscience ,Adenosine Triphosphate ,Adenine nucleotide ,Postsynaptic potential ,medicine ,Animals ,Electric Organ ,Chemistry ,Fishes ,Depolarization ,Bungarotoxins ,Acetylcholine ,Electric Stimulation ,Curare ,Perfusion ,Kinetics ,Potassium ,medicine.drug - Abstract
After labelling ACh tissue stores in Torpedo electric organ prisms with radioactive acetate, the release of ACh and ATP triggered by electrical stimulation or KCI depolarization was measured in the same perfusate samples. The luciferin-luciferase reaction for ATP was first counted, then the radioactive content of the sample determined. Further evidence showing that ATP release resulted from postsynaptic transmitter action was that carbachol could induce the release of ATP. A dose-response curve was obtained. Curare or α-bungarotoxin block the release of ATP elicited by carbachol. When triggered by KCI depolarization the increased efflux of ACh and ATP returned to low levels in spite of the maintained depolarization. After two successive KCI depolarizations, it was possible to dissociate the release of both substances. The efflux of ATP was exhausted while ACh release was maintained. If the second KCI depolarization was delayed ATP release recovered, but the release kinetics of ACh and ATP were sustained. The exhaustion of endogenous ATP release or the action of exogenous ATP had little or no effect on the release of ACh triggered by KCI depolarization. On the contrary, the release of ACh induced by electrical stimulation was sensitive to the action of adenine nucleotides, and a quantitative estimation of the inhibition of ACh release by ATP and adenosine could be made. At the onset of stimulation ATP release predominated, being gradually replaced by adenosine, which can be reuptaken. This would terminate the inhibitory action of the nucleotide. Carbachol inhibits evoked ACh release, while the effect of α-bungarotoxin was to increase spontaneous ACh release. These effects could be respectively mediated by an increased or a reduced release of ATP resulting from the postsynaptic action of ACh agonists or antagonists. However, a direct presynaptic effect of these substances is not excluded. It seems possible that the action of ATP on ACh release can be explained through its inhibition of the depolarization-evoked Ca2+ entry.
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- 1980
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24. RELATED CHANGES IN AMOUNTS OF ACh AND ATP IN RESTING AND ACTIVE TORPEDO NERVE ELECTROPLAQUE SYNAPSES
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J. Marsal, R. Manaranche, P Mastour-Frachon, B. Lesbats, François-Marie Meunier, and Maurice Israël
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Acetates ,Cytosine Nucleotides ,Biology ,Biochemistry ,Synaptic vesicle ,Choline ,law.invention ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,Adenosine Triphosphate ,law ,Postsynaptic potential ,Oscillometry ,medicine ,Animals ,Nucleotide ,Incubation ,chemistry.chemical_classification ,Electric Organ ,Adenine Nucleotides ,Fishes ,Depolarization ,Acetylcholine ,Electric Stimulation ,chemistry ,Synapses ,Biophysics ,Calcium ,Carbachol ,Female ,Guanosine Triphosphate ,Adenosine triphosphate ,Torpedo ,medicine.drug - Abstract
— Closely related changes in the levels of acetylcholine (ACh) and adenosine triphosphate (ATP) in the electric organ of Torpedo exist during rest and synaptic activity. The present work clarifies these relations by showing: 1 That both substances are involved in an oscillatory process induced by nerve stimulation. 2 Both substances are present in synaptic vesicles; the size of the bound pool of ACh is Ca2-dependent and is large when Ca2+ is low. Free ACh and transmission are restored when Ca2+ is present in the incubation medium. 3 The amount of ATP in the tissue is also Ca2+-dependent but is low when Ca2+ is omitted. The addition of Ca2+ to the physiological medium restores the amount of ATP in the tissue. 4 There is a postsynaptic release of ATP triggered by transmitter depolarization. This release was measured after single nerve impulses. 5 When added to the incubation medium, nucleotides strongly inhibit transmitter release. It is suggested that the postsynaptic release of ATP regulates transmitter release.
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- 1977
- Full Text
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25. Calcium-Induced Desensitization of Acetylcholine Release from Synaptosomes or Proteoliposomes Equipped with Mediatophore, a Presynaptic Membrane Protein
- Author
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François-Marie Meunier, Maurice Israël, Nicolas Morel, and B. Lesbats
- Subjects
medicine.medical_specialty ,Proteolipids ,Ionophore ,chemistry.chemical_element ,Nerve Tissue Proteins ,Calcium ,Torpedo ,Biochemistry ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,Desensitization (telecommunications) ,Internal medicine ,medicine ,Animals ,Neurotransmitter ,Calcimycin ,Synaptosome ,Electric Organ ,Gramicidin ,Membrane Proteins ,Acetylcholine ,Kinetics ,Endocrinology ,chemistry ,Biophysics ,Cholinergic ,Synaptosomes ,medicine.drug - Abstract
A "fatigue" of acetylcholine (ACh) release is described in cholinergic synaptosomes stimulated with the calcium ionophore A23187 or gramicidin. A small conditioning calcium entry, which did not trigger a large ACh release, led to a decrease of transmitter release elicited by a second large calcium influx. This fatigue was half-maximal at approximately 30 microM external calcium and developed in a few minutes. In contrast, activation of release by calcium was very rapid and was half-maximal at approximately 0.5 mM external calcium. Activation and desensitization of release could be attributed to the recently identified presynaptic membrane protein, the "mediatophore." Proteoliposomes equipped with purified mediatophore showed a calcium-dependent activation and "fatigue" of ACh release similar to that of synaptosomes. It was found that the ionophore A23187 rapidly equilibrated internal and external calcium concentrations in proteoliposomes. Thus, the external calcium concentration gave the internal concentration required for activation or desensitization of proteoliposomal ACh release. The mediatophore showed remarkable calcium binding properties (20 sites/molecule) with a KD of 25 microM. The physiological implications of desensitization on the organization of release sites are discussed.
- Published
- 1987
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