Search

Your search keyword '"Vignard, Julien"' showing total 167 results
Start Over Author "Vignard, Julien"
167 results on '"Vignard, Julien"'

3. A Fanci knockout mouse model reveals common and distinct functions for FANCI and FANCD2

Author

Dubois, Emilie L, Guitton-Sert, Laure, Béliveau, Mariline, Parmar, Kalindi, Chagraoui, Jalila, Vignard, Julien, Pauty, Joris, Caron, Marie-Christine, Coulombe, Yan, Buisson, Rémi, Jacquet, Karine, Gamblin, Clémence, Gao, Yuandi, Laprise, Patrick, Lebel, Michel, Sauvageau, Guy, d’Andrea, Alan D, and Masson, Jean-Yves

Subjects
Biochemistry and Cell Biology, Biological Sciences, Hematology, Pediatric, Genetics, Rare Diseases, Aetiology, 2.1 Biological and endogenous factors, Animals, Cells, Cultured, DNA Repair, Disease Models, Animal, Fanconi Anemia, Fanconi Anemia Complementation Group D2 Protein, Fanconi Anemia Complementation Group Proteins, Female, Humans, Male, Mice, Inbred C57BL, Mice, Knockout, Oocytes, Rad51 Recombinase, Spermatocytes, Environmental Sciences, Information and Computing Sciences, Developmental Biology, Biological sciences, Chemical sciences, Environmental sciences
Abstract

Fanconi Anemia (FA) clinical phenotypes are heterogenous and rely on a mutation in one of the 22 FANC genes (FANCA-W) involved in a common interstrand DNA crosslink-repair pathway. A critical step in the activation of FA pathway is the monoubiquitination of FANCD2 and its binding partner FANCI. To better address the clinical phenotype associated with FANCI and the epistatic relationship with FANCD2, we created the first conditional inactivation model for FANCI in mouse. Fanci -/- mice displayed typical FA features such as delayed development in utero, microphtalmia, cellular sensitivity to mitomycin C, occasional limb abnormalities and hematological deficiencies. Interestingly, the deletion of Fanci leads to a strong meiotic phenotype and severe hypogonadism. FANCI was localized in spermatocytes and spermatids and in the nucleus of oocytes. Both FANCI and FANCD2 proteins co-localized with RPA along meiotic chromosomes, albeit at different levels. Consistent with a role in meiotic recombination, FANCI interacted with RAD51 and stimulated D-loop formation, unlike FANCD2. The double knockout Fanci-/- Fancd2-/- also showed epistatic relationship for hematological defects while being not epistatic with respect to generating viable mice in crosses of double heterozygotes. Collectively, this study highlights common and distinct functions of FANCI and FANCD2 during mouse development, meiotic recombination and hematopoiesis.

Published
2019

6. Food-grade titanium dioxide translocates across the buccal mucosa in pigs and induces genotoxicity in an in vitro model of human oral epithelium

Author

Vignard, Julien, primary, Pettes-Duler, Aurelie, additional, Gaultier, Eric, additional, Cartier, Christel, additional, Weingarten, Laurent, additional, Biesemeier, Antje, additional, Taubitz, Tatjana, additional, Pinton, Philippe, additional, Bebeacua, Cecilia, additional, Devoille, Laurent, additional, Dupuy, Jacques, additional, Boutet-Robinet, Elisa, additional, Feltin, Nicolas, additional, Oswald, Isabelle P., additional, Pierre, Fabrice H., additional, Lamas, Bruno, additional, Mirey, Gladys, additional, and Houdeau, Eric, additional

Published
2023
Full Text
View/download PDF

7. Human TR146 cells and pig buccal mucosa to assess oral transmucosal passage and buccal toxicity of foodgrade titanium dioxide

Author

Vignard, Julien, Pettes-Duler, Aurélie, Gaultier, Eric, Cartier, Christel, Weingarten, L., Biesemeier, A., Pinton, Philippe, Bebeacua, C., Devoille, Laurent, Dupuy, Jacques, Boutet-Robinet, Elisa, Feltin, Nicolas, Oswald, Isabelle P., Pierre, Fabrice H.F., Lamas, Bruno, Mirey, Gladys, Houdeau, Eric, Génotoxicité & Signalisation (ToxAlim-GS), ToxAlim (ToxAlim), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Ecole Nationale Vétérinaire de Toulouse (ENVT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Ecole d'Ingénieurs de Purpan (INP - PURPAN), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Endocrinologie & Toxicologie de la Barrière Intestinale (ToxAlim-ENTeRisk), Centre de microcaractérisation Raimond Castaing (Centre Castaing), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Luxembourg Institute of Science and Technology (LIST), Biosynthèse & Toxicité des Mycotoxines (ToxAlim-BioToMyc), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Laboratoire National de Métrologie et d'Essais [Trappes] (LNE ), Prévention et promotion de la cancérogénèse par les aliments (ToxAlim-PPCA), and Toxicologie Intégrative & Métabolisme (ToxAlim-TIM)

Subjects
[SDV.TOX]Life Sciences [q-bio]/Toxicology, [SDV.IMM]Life Sciences [q-bio]/Immunology, [SDV.TOX.TCA]Life Sciences [q-bio]/Toxicology/Toxicology and food chain, [SDV.AEN]Life Sciences [q-bio]/Food and Nutrition
Abstract

International audience; Background: Today, the use of titanium dioxide (TiO 2) as food additive (E171) has been banned by the European Commission, due to concerns for human health based on studies showing TiO 2 particles systematically available, tissue accumulation, a genotoxic risk and possible promotion of precancerous lesions. However, E171 is still present in toothpastes and pharmaceutical tablets as a whitening powder mixing nano-and submicronic particles. Risk assessment of TiO 2 intake by oral route is mainly based on the assumption that particles are mainly absorbed by the intestine. However, while the buccal mucosa is the first exposed area, the possibility of an oro-transmucosal passage has not been documented so far. In order to gain insight on possible adverse effects for human health associated to E171 buccal exposure, we analyzed in vivo the translocation of TiO 2 (E171) in the buccal mucosa of pigs used as human mouth model. Moreover, we evaluated in vitro the particle translocation on human buccal TR146 cell line, and measured cytotoxic and genotoxic effects on proliferative and differentiated epithelial cells. Methods & Results: Under realistic exposure conditions with 50 µg/ml of food-grade TiO 2 in water suspension (size distribution 20-440 nm; mean size of 105 nm) deposited under the tongue of pigs, TEM-EDX data revealed the presence of small aggregates of TiO 2 particles translocated into the buccal mucosa from 30 minutes of exposure, reaching submaxillary lymph nodes after 4 hours. In human TR146 cells exposed to E171, kinetic analysis using confocal, TEM and SIMS imaging showed progressive and large uptake of isolated or small aggregates of both submicronic and nanosized particles, showing high permeability capacity. At 2h of E171 exposure, cytotoxicity, genotoxicity and oxidative stress were investigated on both proliferative or differentiated TR146 cells, in comparison with two TiO 2 size standards of 115 nm and 21 nm in diameter. All tested TiO 2 particles were reported cytotoxic on proliferative TR146 cells, and this effect was almost abolished following differentiation. Oxidative stress and genotoxicity assessed through γH2AX and 53BP1 foci formation and comet assay were only reported for E171 sample and TiO 2 particles of 115 nm, suggesting the particles above 20 nm responsive of these effects, and mainly on proliferative cells. Conclusions: Taken together, these results show in vivo and in vitro that the buccal mucosa is an important absorption route for systemic passage of foodborne TiO 2 (E171) particles. In human cells, uptake of TiO2 particles was cytotoxic without size effects, while they generate further oxidative and genotoxic stresses in proliferative buccal cells, that could impair epithelium renewal in the mouth. Altogether, these data emphasize that buccal exposure should be considered for toxicokinetic and risk assessments of TiO2 in human when used as food additive, including in toothpaste and pharmaceutical formulations.

Published
2022

8. Food-grade titanium dioxide translocates across the oral mucosa in pigs and induces genotoxicity in an in vitro model of human oral epithelium

Author

Vignard, Julien, Pettes-Duler, Aurélie, Gaultier, Eric, Cartier, Christel, Weingarten, L., Biesemeier, A., Taubitz, T., Pinton, Philippe, Bebeacua, C., Devoille, Laurent, Dupuy, Jacques, Boutet-Robinet, Elisa, Feltin, Nicolas, Oswald, Isabelle P., Pierre, Fabrice H.F., Lamas, Bruno, Mirey, Gladys, Houdeau, Eric, Génotoxicité & Signalisation (ToxAlim-GS), ToxAlim (ToxAlim), Institut National de la Recherche Agronomique (INRA)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Ecole Nationale Vétérinaire de Toulouse (ENVT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Ecole d'Ingénieurs de Purpan (INP - PURPAN), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National de la Recherche Agronomique (INRA)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT), Endocrinologie & Toxicologie de la Barrière Intestinale (ToxAlim-ENTeRisk), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Centre de microcaractérisation Raimond Castaing (Centre Castaing), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Materials Research and Technology (MRT) Department, Luxembourg Institute of Science and Technology (LIST), Unité de recherche Pharmacologie-Toxicologie (UPT), Institut National de la Recherche Agronomique (INRA), Biosynthèse & Toxicité des Mycotoxines (ToxAlim-BioToMyc), ETH Zurich, Scientific Center for Optical and Electron Microscopy, Laboratoire National de Métrologie et d'Essais [Trappes] (LNE ), Prévention et promotion de la cancérogénèse par les aliments (ToxAlim-PPCA), and Toxicologie Intégrative & Métabolisme (ToxAlim-TIM)

Subjects
food additive, titanium dioxide, [SDV.TOX]Life Sciences [q-bio]/Toxicology, genotoxicity, cytotoxicity, [SDV.IMM]Life Sciences [q-bio]/Immunology, nanoparticles, Oral mucosa, [SDV.TOX.TCA]Life Sciences [q-bio]/Toxicology/Toxicology and food chain, [SDV.AEN]Life Sciences [q-bio]/Food and Nutrition
Abstract

Background Food-grade titanium dioxide (TiO2), composed of nano- and submicron-sized particles, is used worldwide in various foodstuffs, toothpastes and pharmaceutical tablets as a whitening and opacifying agent. Its use as a food additive (E171 in EU) has raised concerns for human health regarding its systemic availability, tissue accumulation, genotoxicity and promotion of precancerous lesions. However, although the buccal mucosa is the first area exposed, oral transmucosal passage of TiO2 particles has not been documented. Here we analyzed TiO2 (E171) particle translocation in vivo through the pig buccal mucosa and in vitro on human buccal TR146 cells, and the effects of E171 on proliferating and differentiated human oral epithelial cells. Results Using transmission electronic microscopy (TEM) coupled to energy-dispersive X-ray spectroscopy (EDX), isolated TiO2 particles and small aggregates were observed in the buccal floor of pigs starting 30 min after the sublingual deposition of E171 suspended in water, and recovered in the submandibular lymph nodes at 4 h. In human TR146 cells exposed to E171, kinetic analyses using confocal microscopy, TEM and high-resolution secondary ion mass spectrometry (SIMS) imaging showed high uptake capacities of both the nano- and submicron-sized TiO2 particles. At 2 h, the cytotoxicity, genotoxicity and oxidative stress were investigated in both proliferating and differentiated TR146 cells exposed to E171 in comparison with two TiO2 size standards of 115 and 21 nm in diameter. All TiO2 samples were reported cytotoxic in proliferating cells, an effect almost abolished following differentiation. Genotoxicity (γH2AX or 53BP1 foci formation and comet assays) and oxidative stress (CellRox reagent) were only reported for the E171 and 115 nm TiO2 particles, and mainly in proliferating cells. Conclusions These data showed that the buccal mucosa is an important absorption route for the systemic passage of food-grade TiO2 particles. In human cells, TiO2 particles are cytotoxic and generate size-dependent oxidative and genotoxic stresses in proliferating cells, potentially impairing oral epithelium renewal. Altogether, these data emphasize that buccal exposure should be considered during toxicokinetic studies and for risk assessment of TiO2 in human when used as food additive, including in toothpastes and pharmaceutical formulations.

Published
2022

10. Very-Long-Chain Fatty Acids Are Involved in Polar Auxin Transport and Developmental Patterning in Arabidopsis

Author

Roudier, François, Gissot, Lionel, Beaudoin, Frédéric, Haslam, Richard, Michaelson, Louise, Marion, Jessica, Molino, Diana, Lima, Amparo, Bach, Liên, Morin, Halima, Tellier, Frédérique, Palauqui, Jean-Christophe, Bellec, Yannick, Renne, Charlotte, Miquel, Martine, DaCosta, Marco, Vignard, Julien, Rochat, Christine, Markham, Jonathan E., Moreau, Patrick, Napier, Jonathan, and Faure, Jean-Denis

Published
2010

13. Cytolethal Distending Toxin Promotes Replicative Stress Leading to Genetic Instability Transmitted to Daughter Cells

Author

Tremblay, William, primary, Mompart, Florence, additional, Lopez, Elisa, additional, Quaranta, Muriel, additional, Bergoglio, Valérie, additional, Hashim, Saleha, additional, Bonnet, Delphine, additional, Alric, Laurent, additional, Mas, Emmanuel, additional, Trouche, Didier, additional, Vignard, Julien, additional, Ferrand, Audrey, additional, Mirey, Gladys, additional, and Fernandez-Vidal, Anne, additional

Published
2021
Full Text
View/download PDF

15. Repeated exposure of Caco-2 versus Caco-2/HT29-MTX intestinal cell models to (nano)silver in vitro: Comparison of two commercially available colloidal silver products

Author

Gillois, Kévin, primary, Stoffels, Charlotte, additional, Leveque, Mathilde, additional, Fourquaux, Isabelle, additional, Blesson, Justine, additional, Mils, Valérie, additional, Cambier, Sébastien, additional, Vignard, Julien, additional, Terrisse, Hélène, additional, Mirey, Gladys, additional, Audinot, Jean-Nicolas, additional, Theodorou, Vassilia, additional, Ropers, Marie-Hélène, additional, Robert, Hervé, additional, and Mercier-Bonin, Muriel, additional

Published
2021
Full Text
View/download PDF

19. Versicolorin A, a precursor in aflatoxins biosynthesis, is a food contaminant toxic for human intestinal cells

Author

Gauthier, Thierry, primary, Duarte-Hospital, Carolina, additional, Vignard, Julien, additional, Boutet-Robinet, Elisa, additional, Sulyok, Michael, additional, Snini, Selma P., additional, Alassane-Kpembi, Imourana, additional, Lippi, Yannick, additional, Puel, Sylvie, additional, Oswald, Isabelle P., additional, and Puel, Olivier, additional

Published
2020
Full Text
View/download PDF

21. A Fanci knockout mouse model reveals common and distinct functions for FANCI and FANCD2

Author

D'Andrea, Alan, Dubois, Emilie, Guitton-Sert, Laure, Béliveau, Mariline, Parmar, Kalindi, Chagraoui, Jalila, Vignard, Julien, Pauty, Joris, Caron, Marie-Christine, Coulombe, Yan, Buisson, Rémi, Jacquet, Karine, Gamblin, Clémence, Gao, Yuandi, Laprise, Patrick, Lebel, Michel, Sauvageau, Guy, D. d’Andrea, Alan, Masson, Jean-Yves, Centre interdisciplinaire de recherche normand en éducation et formation (CIRNEF), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Institut de Recherche Interdisciplinaire Homme et Société (IRIHS), Normandie Université (NU)-Normandie Université (NU)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU), Centre de Recherches en Cancérologie de Toulouse (CRCT), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Institut Cochin (UMR_S567 / UMR 8104), Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Unité de recherche Génétique et amélioration des plantes (GAP), Institut National de la Recherche Agronomique (INRA), University of Tokyo, University of Tokyo, Language and Information Sciences, Laval University Cancer Research Center - Genome Stability Laboratory, Université Laval [Québec] (ULaval), Laboratoire de Biologie Moléculaire de la Cellule (LBMC), Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Centre Hospitalier Universitaire Montréal - Hôpital Hôtel-Dieu, Partenaires INRAE, Laboratory of Molecular Genetics of Stem Cells [University of Montreal], University of Montreal-Institut de Recherche en Immunologie et en Cancérologie [UdeM-Montréal] (IRIC), Université de Montréal (UdeM)-Université de Montréal (UdeM), Cancer Research Center - Centre de recherche sur le cancer [Québec] (CRC), CHU de Québec–Université Laval, Université Laval [Québec] (ULaval)-Université Laval [Québec] (ULaval), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), and Centre de recherche du CHU de Québec-Université Laval (CRCHUQ)

Subjects
Male, congenital, hereditary, and neonatal diseases and abnormalities, DNA Repair, DNA repair, RAD51, [SDV.CAN]Life Sciences [q-bio]/Cancer, [SDV.BC.BC]Life Sciences [q-bio]/Cellular Biology/Subcellular Processes [q-bio.SC], Biology, medicine.disease_cause, 03 medical and health sciences, 0302 clinical medicine, Spermatocytes, Fanconi anemia, hemic and lymphatic diseases, FANCD2, Genetics, medicine, Animals, Humans, [SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM], Cells, Cultured, 030304 developmental biology, Mice, Knockout, 0303 health sciences, Mutation, Nucleic Acid Enzymes, Fanconi Anemia Complementation Group D2 Protein, nutritional and metabolic diseases, [SDV.BDD.MOR]Life Sciences [q-bio]/Development Biology/Morphogenesis, medicine.disease, Phenotype, Fanconi Anemia Complementation Group Proteins, 3. Good health, Mice, Inbred C57BL, Disease Models, Animal, Fanconi Anemia, 030220 oncology & carcinogenesis, Knockout mouse, Oocytes, Female, Rad51 Recombinase, Homologous recombination
Abstract

Emilie L Dubois : CHU de Québec Research Center, HDQ Pavilion, Oncology Division, 9 McMahon, Québec City, QC G1R 3S3, Canada - Department of Molecular Biology, Medical Biochemistry and Pathology; Laval University Cancer Research Center, Québec City, QC G1V 0A6, Canada.; International audience; Fanconi Anemia (FA) clinical phenotypes are het-erogenous and rely on a mutation in one of the 22 FANC genes (FANCA-W) involved in a common inter-strand DNA crosslink-repair pathway. A critical step in the activation of FA pathway is the monoubiquiti-nation of FANCD2 and its binding partner FANCI. To better address the clinical phenotype associated with FANCI and the epistatic relationship with FANCD2, we created the first conditional inactivation model for FANCI in mouse. Fanci −/− mice displayed typical FA features such as delayed development in utero, microphtalmia, cellular sensitivity to mitomycin C, occasional limb abnormalities and hematological deficiencies. Interestingly, the deletion of Fanci leads to a strong meiotic phenotype and severe hypogo-nadism. FANCI was localized in spermatocytes and spermatids and in the nucleus of oocytes. Both FANCI and FANCD2 proteins co-localized with RPA along meiotic chromosomes, albeit at different levels. Consistent with a role in meiotic recombina-tion, FANCI interacted with RAD51 and stimulated D-loop formation, unlike FANCD2. The double knockout Fanci −/− Fancd2 −/− also showed epistatic relationship for hematological defects while being not epistatic with respect to generating viable mice in crosses of double heterozygotes. Collectively, this study highlights common and distinct functions of FANCI and FANCD2 during mouse development, mei-otic recombination and hematopoiesis.

Published
2019

22. Cell transfection of purified cytolethal distending toxin B subunits allows comparing their nuclease activity while plasmid degradation assay does not

Author

Pons, Benoît J, Bezine, Elisabeth, Hanique, Mélissa, Guillet, Valérie, Mourey, Lionel, Chicher, Johana, Frisan, Teresa, Vignard, Julien, Mirey, Gladys, Pons, Benoît J, Bezine, Elisabeth, Hanique, Mélissa, Guillet, Valérie, Mourey, Lionel, Chicher, Johana, Frisan, Teresa, Vignard, Julien, and Mirey, Gladys

Abstract

The Cytolethal Distending Toxin (CDT) is produced by many pathogenic bacteria. CDT is known to induce genomic DNA damage to host eukaryotic cells through its catalytic subunit, CdtB. CdtB is structurally homologous to DNase I and has a nuclease activity, dependent on several key residues. Yet some differences between various CdtB subunit activities, and discrepancies between biochemical and cellular data, have been observed. To better characterise the role of CdtB in the induction of DNA damage, we affinity-purified wild-type and mutants of CdtB, issued from E. coli and H. ducreyi, under native and denaturing conditions. We then compared their nuclease activity by a classic in vitro assay using plasmid DNA, and two different eukaryotic assays-the first assay where host cells were transfected with a plasmid encoding CdtB, the second assay where host cells were directly transfected with purified CdtB. We show here that in vitro nuclease activities are difficult to quantify, whereas CdtB activities in host cells can be easily interpreted and confirmed the loss of function of the catalytic mutant. Our results highlight the importance of performing multiple assays while studying the effects of bacterial genotoxins, and indicate that the classic in vitro assay should be complemented with cellular assays.

Published
2019
Full Text
View/download PDF

23. Outcrossing as an explanation of the apparent unconventional genetic behavior of Arabidopsis thaliana hth mutants

Author

Mercier, Raphael, Jolivet, Sylvie, Vignard, Julien, Durand, Stephanie, Drouaud, Jan, Pelletier, Georges, and Nogue, Fabien

Subjects
RNA -- Research, Arabidopsis thaliana -- Genetic aspects, Gene mutations -- Analysis, Biological sciences
Abstract

The reappearance of HTH alleles in the offspring of homozygous Arabidopsis hth mutants is not consistent with classical Mendelian genetics. It has been suggested that stored RNA may be used to restore genetic information. However, Peng et al. reported that hth mutants tend to display outcrossing and suggested that outcrossing might provide an alternative explanation for the apparent genetic instability. We have confirmed and extended these results, corroborating that the apparent non-Mendelian behavior of hth mutants can be explained by their susceptibility to outcrossing.

Published
2008

24. Cellular study of a bacterial DNA-damaging virulence factor, the cytolethal distending toxin

Author

Pons, Benoît, Vignard, Julien, bezine, Elisabeth, Hashim, Saleha, Lobjois, Valérie, Ducommun, Bernard, Mirey, Gladys, ToxAlim (ToxAlim), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Vétérinaire de Toulouse (ENVT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole d'Ingénieurs de Purpan (INPT - EI Purpan), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA), Institut des Technologies Avancées en sciences du Vivant (ITAV), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Génotoxicité & Signalisation (ToxAlim-GS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA)-Université Toulouse III - Paul Sabatier (UT3), and Contaminants & Stress Cellulaire (ToxAlim-COMICS)

Subjects
[SDV]Life Sciences [q-bio], ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2018

25. Genotoxicity and mutagenicity assessment of food contaminant mixtures present in the French diet

Author

Le Hégarat, L, Kopp, B., Vignard, Julien, Mirey, Gladys, Fessard, V., Zalko, Daniel, Le Hgarat, L., Audebert, M., Génétique moléculaire, génomique, microbiologie (GMGM), Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Agence nationale de sécurité sanitaire de l'alimentation, de l'environnement et du travail (ANSES), ToxAlim (ToxAlim), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Vétérinaire de Toulouse (ENVT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole d'Ingénieurs de Purpan (INPT - EI Purpan), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA), Unité de Toxicologie des Contaminants, Laboratoire de Fougères - ANSES, Agence nationale de sécurité sanitaire de l'alimentation, de l'environnement et du travail (ANSES)-Agence nationale de sécurité sanitaire de l'alimentation, de l'environnement et du travail (ANSES), Génotoxicité & Signalisation (ToxAlim-GS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA)-Université Toulouse III - Paul Sabatier (UT3), and Métabolisme et Xénobiotiques (ToxAlim-MeX)

Subjects
Food Contamination, [SDV.TOX.TCA]Life Sciences [q-bio]/Toxicology/Toxicology and food chain, [SDV.BC.BC]Life Sciences [q-bio]/Cellular Biology/Subcellular Processes [q-bio.SC], PIG-A, Histones, Cell Line, Tumor, Metals, Heavy, Mixture, Humans, toxicité, H2AX, Pesticides, sécurité des aliments, Mutagenicity Tests, genotoxicity, Membrane Proteins, toxicity, risk assessment, toxicologie, Hep G2 Cells, Diet, food safety, [SDV.TOX]Life Sciences [q-bio]/Toxicology, génotoxicité, Comet Assay, France, food contaminants, analyse des risques, contaminant, DNA Damage, Mutagens, toxicology
Abstract

Through diet, people are exposed simultaneously to a variety of contaminants (e.g. heavy metals, mycotoxins, pesticides) that could have combined adverse effects on human health. A previous study identified six main mixtures of food contaminants to which French adult consumers are exposed. These complex mixtures are comprised of 11 to 19 chemicals that have numerous toxic properties. In the present study, we investigated the genotoxic effects of these food contaminants, as single molecules and in mixtures that reflect their occurrence in the French diet, using the γH2AX assay in two human cell lines (HepG2, LS-174 T). Results of detailed analysis of the 49 individual contaminants (including 21 tested in this study) demonstrated a positive genotoxic response to 14 contaminants in HepG2 and 12 in LS-174 T cells. Next, our results indicated that two mixtures out of six triggered significant γH2AX induction after 24 hr of treatment, at concentrations for which individual compounds did not induce any DNA damage, suggesting more than additive interactions between chemicals. γH2AX positive mixtures were then tested for mutagenicity with the innovative in vitro PIG-A assay in HepG2 cells coupled with the soft agar colony formation assay. The two γH2AX positive mixtures led to a significant increase in the frequency of PIG-A GPI-deficient cells and in the number of colonies formed in soft agar. In conclusion, our study demonstrates that two mixtures of contaminants present in the French diet induce genotoxicity and mutagenicity, and that the combined effects of single molecules present in these mixtures are likely not additive, highlighting potential problems for hazard assessment of mixtures. Environ. Mol. Mutagen. 59:742-754, 2018. © 2018 Wiley Periodicals, Inc.

Published
2018

26. Cytolethal Distending Toxin (CDT) exhibits a unique ability to induce micronucleus in infected cells: possible implications regarding activation of the inflammatory response

Author

Vignard, Julien, Pons, Benoît, Fernandez-Vidal, Anne, Mirey, Gladys, Génotoxicité & Signalisation (ToxAlim-GS), ToxAlim (ToxAlim), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Vétérinaire de Toulouse (ENVT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole d'Ingénieurs de Purpan (INPT - EI Purpan), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA)

Subjects
Inflammation, [SDV]Life Sciences [q-bio], micronucleus, Cytolethal Distending Toxin, ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2018

32. Use of a reliable metabolically competent human RGHep + hepatocyte model engineered with biological tracers for in vitro micronucleus test associating high-content imaging

Author

Graillot, Vanessa, primary, Metenier, Thibault, additional, Mondesert, Odile, additional, Vignard, Julien, additional, Lobjois, Valerie, additional, Bazin, Emmanuelle, additional, Camus, Sandrine, additional, Guguen-Guillouzo, Christiane, additional, Li, Ruoya, additional, Chesne, Christophe, additional, Ducommun, Bernard, additional, Salles, Bernard, additional, and Mirey, Gladys, additional

Published
2018
Full Text
View/download PDF

34. In vitro micronucleus test in living cells associating biological tracers and high-content imaging

Author

Mirey, Gladys, primary, Graillot, Vanessa, additional, Mondesert, Odile, additional, Metenier, Thibault, additional, Vignard, Julien, additional, Lobjois, Valerie, additional, Bazin, Emmanuelle, additional, Shevchenko, Valery, additional, Guguen-Guillouzo, Christiane, additional, Chesne, Christophe, additional, Ducommun, Bernard, additional, and Salles, Bernard, additional

Published
2017
Full Text
View/download PDF

36. Overview of the DNA repair pathways involved in response to the cytolethal distending toxin

Author

bezine, Elisabeth, Vignard, Julien, chevalier, Marianne, Boutet-Robinet, Elisa, Salles, Bernard, Mirey, Gladys, ToxAlim (ToxAlim), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Vétérinaire de Toulouse (ENVT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole d'Ingénieurs de Purpan (INPT - EI Purpan), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA), Génotoxicité & Signalisation (ToxAlim-GS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA)-Université Toulouse III - Paul Sabatier (UT3), Contaminants & Stress Cellulaire (ToxAlim-COMICS), Contrat jeune chercheur SA 2012, and EMBO. DEU.

Subjects
[SDV]Life Sciences [q-bio]
Abstract

International audience; The Cytolethal Distending Toxin (CDT) is produced by many pathogenic gram-negative bacteria and its production has been associated to various diseases, including tumorigenesis. The CDT-related pathogenicity relies on the action of the catalytic subunit CdtB, which has been shown to induce double-strand breaks (DSB) on the host cell DNA. Different studies pointed out the importance of DSB repair mechanisms for cells to survive CDT, emphasizing on the homologous recombination repair pathway. Previously, we reported that another type of DNA lesion precede DSB formation through replicative stress. Since various repair pathways allow cells to respond different type of DNA damage, we speculated that non-DSB repair mechanisms might contribute to the cellular resistance to CDT-mediated genotoxicity. To address this question, we use an innovative proliferation assay, on human cell lines depleted in the major DNA repair pathways. Firstly, we confirm that homologous recombination is involved in the management of CDT-induced lesions, but also of Non Homologous End Joining, the second major DSB repair mechanism. Next, we show that nucleotide excision repair is not important to take care of CDT-induced damage, whereas base excision repair (BER) impairment sensitize CDT-treated cells, suggesting that CDT induce single-strand breaks or base modifications. Finally, we demonstrate for the first time the involvement and the activation of the Fanconi Anemia repair pathway in response to CDT. In conclusion, our work supports that CDT-induced damage are plurals and involve different repair pathways. This reinforces a model where CDT induces base damage and underlines the importance of cell proliferation to generate DNA double-strand break damage.

Published
2015

37. Overview of the DNA repair pathways involved in the response to the cytolethal distending toxin

Author

Vignard, Julien, bezine, Elisabeth, Mirey, Gladys, Salles, Bernard, Boutet-Robinet, Elisa, chevalier, Marianne, Génotoxicité & Signalisation (ToxAlim-GS), ToxAlim (ToxAlim), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Vétérinaire de Toulouse (ENVT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole d'Ingénieurs de Purpan (INPT - EI Purpan), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA), Contaminants & Stress Cellulaire (ToxAlim-COMICS), and Contrat jeune chercheur SA 2012

Subjects
[SDV]Life Sciences [q-bio], cytolethal distending toxin, ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2015

38. Exposure to the Fungicide Captan Induces DNA Base Alterations and Replicative Stress in Mammalian Cells.

Author

Fernandez‐Vidal, Anne, Arnaud, Liana C., Maumus, Manon, Chevalier, Marianne, Mirey, Gladys, Salles, Bernard, Vignard, Julien, and Boutet‐Robinet, Elisa

Subjects
DNA replication, PSYCHOLOGICAL stress, DNA
Abstract

The classification of the fungicide captan (CAS Number: 133–06‐2) as a carcinogen agent is presently under discussion. Despite the mutagenic effect detected by the Ames test and carcinogenic properties observed in mice, the genotoxicity of this pesticide in humans is still unclear. New information is needed about its mechanism of action in mammalian cells. Here, we show that Chinese Hamster Ovary (CHO) cells exposed to captan accumulate Fpg‐sensitive DNA base alterations. In CHO and HeLa cells, such DNA lesions require the XRCC1‐dependent pathway to be repaired. Captan also induces a replicative stress that activated the ATR signaling response and resulted in double‐strand breaks and micronuclei. The replicative stress is characterized by a dramatic decrease in DNA synthesis due to a reduced replication fork progression. However, impairment of the XRCC1‐related repair process did not amplify the replicative stress, suggesting that the fork progression defect is independent from the presence of base modifications. These results support the involvement of at least two independent pathways in the genotoxic effect of captan that might play a key role in carcinogenesis. Environ. Mol. Mutagen. 60:286–297, 2019. © 2018 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

40. VHH-based universal histone binding domains: novel tools for a different look on and manipulation of chromatin

Author

jullien, Denis, Vignard, Julien, FEDOR, Yoann, Olichon, Aurélien, Salles, Bernard, Ducommun, Bernard, Mirey, Gladys, ITAVI, Génotoxicité & Signalisation (ToxAlim-GS), ToxAlim (ToxAlim), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Vétérinaire de Toulouse (ENVT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole d'Ingénieurs de Purpan (INPT - EI Purpan), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA), Centre de Recherches en Cancérologie de Toulouse (CRCT), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDV]Life Sciences [q-bio], ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2014

41. Nanobody-based universal histone binding domains for chromatin imaging and editing

Author

jullien, Denis, Vignard, Julien, FEDOR, Yoann, Olichon, Aurélien, Crozatier, Michèle, Salles, Bernard, Ducommun, Bernard, Mirey, Gladys, ToxAlim (ToxAlim), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Vétérinaire de Toulouse (ENVT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole d'Ingénieurs de Purpan (INPT - EI Purpan), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA), Génotoxicité & Signalisation (ToxAlim-GS), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA)-Université Toulouse III - Paul Sabatier (UT3)

Subjects
[SDV]Life Sciences [q-bio], ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2014

42. The effect of Cytolethal Distending Toxin from Gram-negative bacteria on mammalian cells

Author

bezine, Elisabeth, Vignard, Julien, Mirey, Gladys, ToxAlim (ToxAlim), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Vétérinaire de Toulouse (ENVT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole d'Ingénieurs de Purpan (INPT - EI Purpan), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA), Génotoxicité & Signalisation (ToxAlim-GS), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA)-Université Toulouse III - Paul Sabatier (UT3)

Subjects
[SDV]Life Sciences [q-bio], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2014

45. A new mode of action of a bacterial genotoxin: the cytolethal distending toxin

Author

bezine, Elisabeth, Fedor, Yoann, Vignard, Julien, Boutet-Robinet, Elisa, Salles, Bernard, Mirey, Gladys, Génotoxicité & Signalisation (ToxAlim-GS), ToxAlim (ToxAlim), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Vétérinaire de Toulouse (ENVT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole d'Ingénieurs de Purpan (INPT - EI Purpan), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA), Contaminants & Stress Cellulaire (ToxAlim-COMICS), and Sciences Ecologiques, Vétérinairres, Agronomiques et Bioingénieries (SEVAB). FRA.

Subjects
[SDV]Life Sciences [q-bio]
Abstract

National audience; The Cytolethal Distending Toxin (CDT) is a virulence factor produced by many pathogenic bacteria like Escherichia coli, Salmonella typhi, etc. The CDT production allows bacteria to persistently colonize the body and to evade the immune system. Moreover, the production of CDT by Helicobacter hepaticus leads to the development of pre-cancerous lesions liver, in a rat model. It is essential to understand effects of CDT on our body and so characterize the effect of CDT on eukaryotic cells. Into cells, CDT induces DNA double-stranded breaks (DSB), leading to a block of the proliferation and to cell death. However, we have shown that at doses 1000 times lower than those used in the literature, CDT induces single-strand breaks, and after replication, this damages will degenerate into DSB. The importance of the replication passage suggests that proliferating cells are more sensitive to CDT than quiescent cells. Some bacteria producing CDT colonize the intestinal epithelium, where some cells proliferate a lot. This raises the question of the involvement of CDT in the carcinogenesis of this epithelium. To better characterize the effect of CDT on our DNA and especially during replication, we are studying the catalytic activity of CDT and its interaction with the DNA.

Published
2013

46. A new mode of action for the cytolethal distending toxin

Author

bezine, Elisabeth, Fedor, Yoann, Vignard, Julien, Boutet-Robinet, Elisa, Salles, Bernard, Mirey, Gladys, Génotoxicité & Signalisation (ToxAlim-GS), ToxAlim (ToxAlim), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Vétérinaire de Toulouse (ENVT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole d'Ingénieurs de Purpan (INPT - EI Purpan), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA), Contaminants & Stress Cellulaire (ToxAlim-COMICS), and EMBO. DEU.

Subjects
[SDV]Life Sciences [q-bio]
Abstract

International audience; The Cytolethal Distending Toxin (CDT) is a virulence factor produced by many pathogenic bacteria like E. coli, H. hepaticus, H. ducreyi etc. The CDT Production allows bacteria to persistently colonize the body, evade the immune system, induce inflammation and trigger genetic instability. In fact, CDT induces DNA double-stranded breaks (DSB), leading to cell cycle arrest and to cytotoxicity, associated with a characteristic cellular distension. Our objectives are to characterize the type of DNA damage induced by CDT and study the cell sensitivity to different CDT doses, with the cell cycle as read-out. Thanks to comet assay and immunofluorescence, we have shown that at doses 1000 times lower than those used in the literature, CDT induces multiple single-strand breaks. When cells are going through S phase, a replicative stress is induced and DNA damage degenerate into DSB. Indeed, with a PCNA marker, we observed a S phase slowing down and an increase of the number of cells in late S-phase. Moreover, these CDT-induced DNA damage cause the activation of the pathway involving the RPA, ATR and CHK1 proteins, characteristics of a replicative stress. Finally, the activation of the ATM pathway, due to DSB induction, happens later after the CDT treatment. Therefore, the importance of the S-phase passage for the CDT cytotoxicity suggests that proliferating cells are more sensitive to CDT than quiescent cells. Another part of our project is to better characterize the CDT catalytic activity. As CdtB, the catalitic sub-unit of CDT, display DNase and phosphatase activities, we are developing specific mutants to dissociate these activities. The experiments are progressing and the results will be presented. Our work underlines the complex mechanism of CDT action. It will help in the characterization of CDT-expressing bacteria and may open new therapeutic approaches, for example by targeting the mechanisms of associated genotoxicity.

Published
2013

47. Anticorps monocaténaire à chaîne lourde de camelidae dirigé contre la chromatine et utilisations

Author

jullien, Denis, Vignard, Julien, Salles, Bernard, Mirey, Gladys, ToxAlim (ToxAlim), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Vétérinaire de Toulouse (ENVT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole d'Ingénieurs de Purpan (INPT - EI Purpan), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA), Génotoxicité & Signalisation (ToxAlim-GS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA)-Université Toulouse III - Paul Sabatier (UT3), and ANR

Subjects
[SDV.BIO]Life Sciences [q-bio]/Biotechnology, N° 13 55941
Published
2013

48. From single-strand breaks to double-strand breaks during S-phase: a new mode of action of the Escherichia coli Cytolethal Distending Toxin

Author

Fedor, YOANN, Vignard, Julien, Travers, MARIE-LAURE, Boutet-Robinet, Elisa, Watrin, Claude, Salles, Bernard, Mirey, Gladys, ToxAlim (ToxAlim), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Vétérinaire de Toulouse (ENVT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole d'Ingénieurs de Purpan (INPT - EI Purpan), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA), Génotoxicité & Signalisation (ToxAlim-GS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA)-Université Toulouse III - Paul Sabatier (UT3), Contaminants & Stress Cellulaire (ToxAlim-COMICS), Centre de Physiopathologie de Toulouse-Purpan (INSERM U563 - CNRS UMR1037), Centre National de la Recherche Scientifique (CNRS)-Centre de lutte contre le cancer (CLCC)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Hôpital Purpan [Toulouse], CHU Toulouse [Toulouse]-CHU Toulouse [Toulouse]-Institut Claudius Regaud, Centre de Physiopathologie Toulouse Purpan (CPTP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), ANR programme [ANR-10-CESA-011], MYCA programme (Midi-Pyrenees region), and French Ministry of Higher Education and Scientific Research

Subjects
ACTIVATION, REPAIR, CELL-CYCLE ARREST, COMET ASSAY, integumentary system, DNA-DAMAGE, MAMMALIAN-CELLS, [SDV]Life Sciences [q-bio], BACTERIAL GENOTOXIN, HISTONE H2AX PHOSPHORYLATION, HOMOLOGOUS RECOMBINATION, ACTINOBACILLUS-ACTINOMYCETEMCOMITANS
Abstract

International audience; The Cytolethal Distending Toxin (CDT) is a genotoxin produced by several pathogenic bacteria. It is generally admitted that CDT induces double-strand breaks (DSB) and cell cycle arrest in G2/M-phase, in an ATM-dependent manner. Most of these results were obtained at high dose (over 1 mu g ml(-1)) of CDT and late after treatment (8-24 h). We provide here evidence that the Escherichia coli CDT (EcCDT) - at low dose (50 pg ml(-1) or LD50) and early after treatment (3-6 h) -progressively induces DNA DSB, mostly in S-phase. DSB formation is related to the single-strand breaks induction by CDT, converted into DSB during the S-phase. We also show that homologous recombination is mobilized to these S-phase-associated DSB. This model unveils a new mechanism for CDT genotoxicity that may play a role in cells partly deficient in homologous recombination.

Published
2013

49. Campylobacter jejunipromotes colorectal tumorigenesis through the action of cytolethal distending toxin

Author

He, Zhen, Gharaibeh, Raad Z, Newsome, Rachel C, Pope, Jllian L, Dougherty, Michael W, Tomkovich, Sarah, Pons, Benoit, Mirey, Gladys, Vignard, Julien, Hendrixson, David R, and Jobin, Christian

Abstract

ObjectiveCampylobacter jejuniproduces a genotoxin, cytolethal distending toxin (CDT), which has DNAse activity and causes DNA double-strand breaks. Although C. jejuniinfection has been shown to promote intestinal inflammation, the impact of this bacterium on carcinogenesis has never been examined.DesignGerm-free (GF) ApcMin/+mice, fed with 1% dextran sulfate sodium, were used to test tumorigenesis potential of CDT-producing C. jejuni. Cells and enteroids were exposed to bacterial lysates to determine DNA damage capacity via γH2AX immunofluorescence, comet assay and cell cycle assay. To examine the interplay of CDT-producing C. jejuni, gut microbiome and host in tumorigenesis, colonic RNA-sequencing and faecal 16S rDNA sequencing were performed. Rapamycin was administrated to investigate the prevention of CDT-producing C. jejuni-induced tumorigenesis.ResultsGF ApcMin/+mice colonised with human clinical isolate C. jejuni81–176 developed significantly more and larger tumours when compared with uninfected mice. C. jejuniwith a mutated cdtBsubunit, mutcdtB, attenuated C. jejuni-induced tumorigenesis in vivo and decreased DNA damage response in cells and enteroids. C. jejuniinfection induced expression of hundreds of colonic genes, with 22 genes dependent on the presence of cdtB.The C. jejuni-infected group had a significantly different microbial gene expression profile compared with the mutcdtBgroup as shown by metatranscriptomic data, and different microbial communities as measured by 16S rDNA sequencing. Finally, rapamycin could diminish the tumorigenic capability of C. jejuni.ConclusionHuman clinical isolate C. jejuni81–176 promotes colorectal cancer and induces changes in microbial composition and transcriptomic responses, a process dependent on CDT production.

Published
2019
Full Text
View/download PDF

50. Effets génotoxiques de la cytolethal distending toxin et mécanismes de signalisations

Author

bezine, Elisabeth, Fedor, Yoann, Vignard, Julien, Boutet-Robinet, Elisa, Salles, Bernard, Mirey, Gladys, ToxAlim (ToxAlim), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Vétérinaire de Toulouse (ENVT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole d'Ingénieurs de Purpan (INPT - EI Purpan), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA), Génotoxicité & Signalisation (ToxAlim-GS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA)-Université Toulouse III - Paul Sabatier (UT3), Contaminants & Stress Cellulaire (ToxAlim-COMICS), and Institut National de Recherche Agronomique (INRA). UMR Toxicologie Alimentaire (1331).

Subjects
[SDV]Life Sciences [q-bio]
Abstract

National audience; La Cytolethal Distending Toxin (CDT) est un facteur de virulence produit par de nombreuses bactéries pathogènes (Escherichia coli, Helicobacter hepaticus, Haemophilus ducreyi, etc)) colonisant la cavité buccale, le tractus intestinal, le foie etc. La présence de bactéries produisant des génotoxines dans la flore intestinale, comme E. coli, pourrait représenter un facteur prédisposant au développement de cancer, dont celui du côlon, responsable de 500 000 décès par an dans le monde. La toxine CDT a été découverte à partir d’isolats cliniques de patients souffrant de diarrhées causées par une infection à Escherichia coli (Johnson and Lior., 1988) Plusieurs études ont montré que la toxine CDT est un facteur de virulence, jouant un rôle dans la pathogénicité des bactéries qui la produisent (Ge et al., 2008). En effet, la toxine CDT est essentielle pour que Helicobacter hepaticus et Campilobacter jejuni colonisent durablement le système gastro-intestinal et puissent induire une inflammation sévère des muqueuses ou du foie, dans un modèle murin. De plus, dans un modèle murin immunocompétent, l’expression de CDT par H. hepaticus stimule le développement d’infections hépatiques et l’apparition de nodules dysplasiques hépatiques (Ge et al., 2007). Compte tenu du rôle de CDT dans la pathogénicité des bactéries qui la produisent, il est donc fondamental de caractériser précisément le mécanisme d’action de cette toxine sur les cellules eucaryotes. Dans la littérature, il a été caractérisé que CDT induit des cassures double-brin (CDB) de l’ADN, conduisant à un arrêt du cycle cellulaire en G1/S ou G2/M, une activation des systèmes de réparation de l’ADN, une inhibition de la prolifération et une augmentation de la mort des cellules par apoptose. CDT agit donc comme une génotoxine et une cyclomoduline. Afin de protéger l’intégrité de leur génome, les cellules eucaryotes possèdent des mécanismes de détection et de signalisation des dommages à l’ADN. L’induction de dommages à l’ADN par la toxine CDT entraîne une cascade de signalisation similaire à celle activée en réponse aux irradiations. En effet, la voie de réponse aux CDB dépendante des kinases ATM et CHK2 est activée (Alaoui-El-Azher et al., 2010 ; pour revue, Jinadasa et al., 2011). Cependant, nous avons montré qu’à des doses 1000 fois plus faibles que celles utilisées dans la littérature, CDT induit des cassures simple-brins multiples qui, lors de la réplication, induisent un stress réplicatif avant de dégénérer en CDB. Ces dommages entraînent une activation de la voie impliquant les protéines RPA, ATR, et CHK1, caractéristiques d’un stress réplicatif, avant une activation de la voie ATM. En se basant sur ces résultats, nos futurs objectifs seront 1- de caractériser la sensibilité des cellules en fonction des différentes phases du cycle cellulaire, 2- de définir les dommages induits ainsi que 3- définir le(s) mécanisme(s) de réparation(s) impliqué(s) dans la prise en charge de ces dommages.

Published
2012

Catalog

Books, media, physical & digital resources
See catalog results