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11 results on '"Vignard, Julien"'

1. Cellular study of a bacterial DNA-damaging virulence factor, the Cytolethal Distending Toxin

Author

Pons, Benoît, Vignard, Julien, bezine, Elisabeth, Dupuy, Jean-Sébastien, Hashim, Saleha, Lobjois, Valerie, Ducommun, Bernard, Mirey, Gladys, Institut des Technologies Avancées en sciences du Vivant (ITAV), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Génotoxicité & Signalisation (ToxAlim-GS), ToxAlim (ToxAlim), 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), Université Fédérale Toulouse Midi-Pyrénées, and CHU Toulouse [Toulouse]

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

National audience; Genotoxic agents alter the genetic information by damaging DNA inside living cells, leading to genetic instability and carcinogenesis. Several bacteria from the human microbiota produce genotoxic virulence factors, called genotoxin. Thus, cells from the gastro-intestinal tract firstly, and cells from other tissues after systemic passage, are susceptible to suffer DNA damage from those compounds. Among these genotoxins, the Cytolethal Distending Toxin (CDT) is produced by several pathogenic bacteria, some of them being associated with an increased colorectal cancer risk. Some CDT-producing bacteria have been found around tumours, however the carcinogenic potential of CDT in the gastro-intestinal tract has not been directly proven to date. On the other hand, CDT of Helicobacter hepaticus has been shown to induce several cancerous markers in mice (chronic inflammation, hepatic infections and dysplastic nodules). In cell culture models, CDT induces DNA breaks, disturbs the cell cycle and may lead to cell senescence or cell death. Preliminary results show that cell sensitivity to the toxin depends on cell type, the toxin-producing bacteria and cell cycle phases. This raises several questions, particularly concerning the CDT mechanisms of action that may explain its physiopathology. As cell susceptibility to CDT might be linked to CDT internalisation (i.e. host cell recognition) or ability to induce DNA damage, we are developing tools and imaging systems to answer these issues. First, we designed a cellular assay to compare CDT activities and relate its mode of action to cellular effects. Secondly, a live-cell microscopy approach is developed to explore the impact of CDT on cell cycle. Overall, the goal of this project is to develop innovative cellular approaches to better characterise CDT mechanism of action as a first step to get more insight on the effects of the toxin on human health.

Published
2018

2. 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

3. 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

4. Genotoxicity of Cytolethal Distending Toxin (CDT) on Isogenic Human Colorectal Cell Lines: Potential Promoting Effects for Colorectal Carcinogenesis.

Author

Graillot, Vanessa, Dormoy, Inge, Dupuy, Jacques, Shay, Jerry W., Huc, Laurence, Mirey, Gladys, Vignard, Julien, Ryan, Elizabeth J., and DiRienzo, Joseph Michael

Subjects
COLON cancer, GENETIC toxicology, ESCHERICHIA coli toxins, RAS oncogenes, GENETIC mutation
Abstract

The composition of the human microbiota influences tumorigenesis, notably in colorectal cancer (CRC). Pathogenic Escherichia coli possesses a variety of virulent factors, among them the Cytolethal Distending Toxin (CDT). CDT displays dual DNase and phosphatase activities and induces DNA double strand breaks, cell cycle arrest and apoptosis in a broad range of mammalian cells. As CDT could promote malignant transformation, we investigated the cellular outcomes induced by acute and chronic exposures to E. coli CDT in normal human colon epithelial cells (HCECs). Moreover, we conducted a comparative study between isogenic derivatives cell lines of the normal HCECs in order to mimic the mutation of three major genes found in CRC genetic models: APC, KRAS, and TP53. Our results demonstrate that APC and p53 deficient cells showed impaired DNA damage response after CDT exposure, whereas HCECs expressing oncogenic KRASV12 were more resistant to CDT. Compared to normal HCECs, the precancerous derivatives exhibit hallmarks of malignant transformation after a chronic exposure to CDT. HCECs defective in APC and p53 showed enhanced anchorage independent growth and genetic instability, assessed by the micronucleus formation assay. In contrast, the ability to grow independently of anchorage was not impacted by CDT chronic exposure in KRASV12 HCECs, but micronucleus formation is dramatically increased. Thus, CDT does not initiate CRC by itself, but may have promoting effects in premalignant HCECs, involving different mechanisms in function of the genetic alterations associated to CRC. [ABSTRACT FROM AUTHOR]

Published
2016
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5. The Cytolethal Distending Toxin Effects on Mammalian Cells: A DNA Damage Perspective.

Author

Bezine, Elisabeth, Vignard, Julien, and Mirey, Gladys

Subjects
*CELL-mediated cytotoxicity, *DNA damage, *GRAM-negative bacteria, *VIRULENCE of bacteria, *HUMAN cell cycle, *CELL death, *DNA replication
Abstract

The cytolethal distending toxin (CDT) is produced by many pathogenic Gram-negative bacteria and is considered as a virulence factor. In human cells, CDT exposure leads to a unique cytotoxicity associated with a characteristic cell distension and induces a cell cycle arrest dependent on the DNA damage response (DDR) triggered by DNA double-strand breaks (DSBs). CDT has thus been classified as a cyclomodulin and a genotoxin. Whereas unrepaired damage can lead to cell death, effective, but improper repair may be detrimental. Indeed, improper repair of DNA damage may allow cells to resume the cell cycle and induce genetic instability, a hallmark in cancer. In vivo, CDT has been shown to induce the development of dysplastic nodules and to lead to genetic instability, defining CDT as a potential carcinogen. It is therefore important to characterize the outcome of the CDT-induced DNA damage and the consequences for intoxicated cells and organisms. Here, we review the latest results regarding the host cell response to CDT intoxication and focus on DNA damage characteristics, cell cycle modulation and cell outcomes. [ABSTRACT FROM AUTHOR]

Published
2014
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6. Functional Study of Haemophilus ducreyi Cytolethal Distending Toxin Subunit B.

Author

Pons, Benoît J., Loiseau, Nicolas, Hashim, Saleha, Tadrist, Soraya, Mirey, Gladys, and Vignard, Julien

Subjects
HAEMOPHILUS, DNA damage, TOXINS, CELL cycle, FOODBORNE diseases
Abstract

The Cytolethal Distending Toxin (CDT) is produced by many Gram-negative pathogenic bacteria responsible for major foodborne diseases worldwide. CDT induces DNA damage and cell cycle arrest in host-cells, eventually leading to senescence or apoptosis. According to structural and sequence comparison, the catalytic subunit CdtB is suggested to possess both nuclease and phosphatase activities, carried by a single catalytic site. However, the impact of each activity on cell-host toxicity is yet to be characterized. Here, we analyze the consequences of cell exposure to different CDT mutated on key CdtB residues, focusing on cell viability, cell cycle defects, and DNA damage induction. A first class of mutant, devoid of any activity, targets putative catalytic (H160A), metal binding (D273R), and DNA binding residues (R117A-R144A-N201A). The second class of mutants (A163R, F156-T158, and the newly identified G114T), which gathers mutations on residues potentially involved in lipid substrate binding, has only partially lost its toxic effects. However, their defects are alleviated when CdtB is artificially introduced inside cells, except for the F156-T158 double mutant that is defective in nuclear addressing. Therefore, our data reveal that CDT toxicity is mainly correlated to CdtB nuclease activity, whereas phosphatase activity may probably be involved in CdtB intracellular trafficking. [ABSTRACT FROM AUTHOR]

Published
2020
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7. Cytolethal Distending Toxin Subunit B: A Review of Structure–Function Relationship.

Author

Pons, Benoît J., Vignard, Julien, and Mirey, Gladys

Subjects
*TOXINS, *PATHOGENIC bacteria, *GRAM-negative bacteria, *CELL death, *CELL cycle
Abstract

The Cytolethal Distending Toxin (CDT) is a bacterial virulence factor produced by several Gram-negative pathogenic bacteria. These bacteria, found in distinct niches, cause diverse infectious diseases and produce CDTs differing in sequence and structure. CDTs have been involved in the pathogenicity of the associated bacteria by promoting persistent infection. At the host-cell level, CDTs cause cell distension, cell cycle block and DNA damage, eventually leading to cell death. All these effects are attributable to the catalytic CdtB subunit, but its exact mode of action is only beginning to be unraveled. Sequence and 3D structure analyses revealed similarities with better characterized proteins, such as nucleases or phosphatases, and it has been hypothesized that CdtB exerts a biochemical activity close to those enzymes. Here, we review the relationships that have been established between CdtB structure and function, particularly by mutation experiments on predicted key residues in different experimental systems. We discuss the relevance of these approaches and underline the importance of further study in the molecular mechanisms of CDT toxicity, particularly in the context of different pathological conditions. [ABSTRACT FROM AUTHOR]

Published
2019
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8. Chronic exposure to Cytolethal Distending Toxin (CDT) promotes a cGAS-dependent type I interferon response

Author

Claire Naylies, Gladys Mirey, Patrick Rouimi, Benoît J. Pons, Maxime Deslande, Saleha Hashim, Julien Vignard, Catherine Bouchenot, Yannick Lippi, Frédéric Taieb, Aurélie Pettes-Duler, Génotoxicité & Signalisation (ToxAlim-GS), ToxAlim (ToxAlim), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-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-Institut National Polytechnique (Toulouse) (Toulouse INP), 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 Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Endocrinologie & Toxicologie de la Barrière Intestinale (ToxAlim-ENTeRisk), Transcriptomic impact of Xenobiotics (E23 TRiX), Plateforme Génome & Transcriptome (GET), Génopole Toulouse Midi-Pyrénées [Auzeville] (GENOTOUL), Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Génopole Toulouse Midi-Pyrénées [Auzeville] (GENOTOUL), Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-ToxAlim (ToxAlim), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Ecole d'Ingénieurs de Purpan (INPT - EI Purpan), Ecole Nationale Vétérinaire de Toulouse (ENVT), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, Contaminants & Stress Cellulaire (ToxAlim-COMICS), This work was supported by the ANR Grant No ANR-10-CESA-011 to G. Mirey, the Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE) and the Toxalim internal program to J. Vignard. B.J. Pons was supported by a Ph.D. fellowship granted by the COLiveTox IDEX Toulouse University., ANR-10-CESA-0011,GENOTOXTRACK,Biomarqueurs de génotoxicité ex vivo et in vivo.(2010), Vignard, Julien, CONTAMINANTS, ECOSYSTEMES, SANTE - Biomarqueurs de génotoxicité ex vivo et in vivo. - - GENOTOXTRACK2010 - ANR-10-CESA-0011 - CES - VALID, Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Ecole Nationale Vétérinaire de Toulouse (ENVT), Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-Génopole Toulouse Midi-Pyrénées [Auzeville] (GENOTOUL), and Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-ToxAlim (ToxAlim)

Subjects
0301 basic medicine, Cell division, Cytolethal distending toxin, [SDV]Life Sciences [q-bio], [SDV.BC.BC]Life Sciences [q-bio]/Cellular Biology/Subcellular Processes [q-bio.SC], DNA damage response, medicine.disease_cause, [SDV.IMM.II]Life Sciences [q-bio]/Immunology/Innate immunity, Mice, 0302 clinical medicine, Interferon, DNA Breaks, Double-Stranded, Nucleotidyltransferases, 3. Good health, Cell biology, Up-Regulation, Interferon Type I, cGAS-STING axis, Molecular Medicine, medicine.drug, DNA damage, Bacterial Toxins, Bacterial genotoxin, Mitosis, [SDV.TOX.TCA]Life Sciences [q-bio]/Toxicology/Toxicology and food chain, Biology, 03 medical and health sciences, Cellular and Molecular Neuroscience, Immune system, [SDV.BC.BC] Life Sciences [q-bio]/Cellular Biology/Subcellular Processes [q-bio.SC], medicine, Animals, Humans, Fragmentation (cell biology), [SDV.IMM.II] Life Sciences [q-bio]/Immunology/Innate immunity, Interferon-stimulated genes, Molecular Biology, Pharmacology, Epithelial Cells, Cell Biology, Cell Cycle Checkpoints, Fibroblasts, [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology, 030104 developmental biology, [SDV.TOX.TCA] Life Sciences [q-bio]/Toxicology/Toxicology and food chain, Micronucleus, [SDV.MP.BAC] Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology, Carcinogenesis, 030217 neurology & neurosurgery, HeLa Cells
Abstract

The Cytolethal Distending Toxin (CDT) is a bacterial genotoxin produced by pathogenic bacteria causing major foodborne diseases worldwide. CDT activates the DNA Damage Response and modulates the host immune response, but the precise relationship between these outcomes has not been addressed so far. Here, we show that chronic exposure to CDT in HeLa cells or mouse embryonic fibroblasts promotes a strong type I interferon (IFN) response that depends on the cytoplasmic DNA sensor cyclic guanosine monophosphate (GMP)-adenosine monophosphate (AMP) synthase (cGAS) through the recognition of micronuclei. Indeed, despite active cell cycle checkpoints and in contrast to other DNA damaging agents, cells exposed to CDT reach mitosis where they accumulate massive DNA damage, resulting in chromosome fragmentation and micronucleus formation in daughter cells. These mitotic phenotypes are observed with CDT from various origins and in cancer or normal cell lines. Finally, we show that CDT exposure in immortalized normal colonic epithelial cells is associated to cGAS protein loss and low type I IFN response, implying that CDT immunomodulatory function may vary depending on tissue and cell type. Thus, our results establish a direct link between CDT-induced DNA damage, genetic instability and the cellular immune response that may be relevant in the context of natural infection associated to chronic inflammation or carcinogenesis.

Published
2021
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9. The Cytolethal Distending Toxin Effects on Mammalian Cells: A DNA Damage Perspective

Author

Julien Vignard, Gladys Mirey, Elisabeth Bezine, 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), Génotoxicity Signaling Team, Institut National de la Recherche Agronomique (INRA), Genotoxicity Signaling Team, Vignard, Julien, Mirey, Gladys, 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
Programmed cell death, Cell cycle checkpoint, Cytolethal distending toxin, DNA damage, [SDV]Life Sciences [q-bio], Cell, replicative stress, Review, Biology, DNA damage response, Microbiology, chemistry.chemical_compound, medicine, lcsh:QH301-705.5, Carcinogen, double-strand breaks, General Medicine, Cell cycle, 3. Good health, Cell biology, medicine.anatomical_structure, lcsh:Biology (General), chemistry, Gram-negative bacteria, cytolethal distending toxin, cell cycle checkpoints, DNA
Abstract

The cytolethal distending toxin (CDT) is produced by many pathogenic Gram-negative bacteria and is considered as a virulence factor. In human cells, CDT exposure leads to a unique cytotoxicity associated with a characteristic cell distension and induces a cell cycle arrest dependent on the DNA damage response (DDR) triggered by DNA double-strand breaks (DSBs). CDT has thus been classified as a cyclomodulin and a genotoxin. Whereas unrepaired damage can lead to cell death, effective, but improper repair may be detrimental. Indeed, improper repair of DNA damage may allow cells to resume the cell cycle and induce genetic instability, a hallmark in cancer. In vivo, CDT has been shown to induce the development of dysplastic nodules and to lead to genetic instability, defining CDT as a potential carcinogen. It is therefore important to characterize the outcome of the CDT-induced DNA damage and the consequences for intoxicated cells and organisms. Here, we review the latest results regarding the host cell response to CDT intoxication and focus on DNA damage characteristics, cell cycle modulation and cell outcomes.

Published
2014
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10. Cell resistance to the Cytolethal Distending Toxin involves an association of DNA repair mechanisms

Author

Julien Vignard, Bernard Salles, Yann Malaisé, Elisa Boutet-Robinet, Aurore Loeuillet, Gladys Mirey, Marianne Chevalier, Elisabeth Bezine, Mirey, Gladys, Vignard, Julien, 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), Contaminants & Stress Cellulaire (ToxAlim-COMICS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA)-Université Toulouse III - Paul Sabatier (UT3), Génotoxicité & Signalisation (ToxAlim-GS), Agence Nationale de la Recherche (ANR) program [ANR-10-CESA-011], Institut National de la Recherche Agronomique, INP (Institut National Polytechnique de Toulouse), 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-Ecole Nationale Vétérinaire de Toulouse (ENVT), Université Fédérale Toulouse Midi-Pyrénées-Ecole d'Ingénieurs de Purpan (INPT - EI Purpan), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées

Subjects
DNA Replication, 0301 basic medicine, DNA End-Joining Repair, Cytolethal distending toxin, DNA repair, DNA damage, [SDV]Life Sciences [q-bio], Bacterial Toxins, Biology, Article, 03 medical and health sciences, Fanconi anemia, medicine, Humans, DNA Breaks, Double-Stranded, Homologous Recombination, Multidisciplinary, 030102 biochemistry & molecular biology, Mutagenesis, HCT116 Cells, medicine.disease, Cell biology, Non-homologous end joining, 030104 developmental biology, Homologous recombination, HeLa Cells, Nucleotide excision repair
Abstract

The Cytolethal Distending Toxin (CDT), produced by many bacteria, has been associated with various diseases including cancer. CDT induces DNA double-strand breaks (DSBs), leading to cell death or mutagenesis if misrepaired. At low doses of CDT, other DNA lesions precede replication-dependent DSB formation, implying that non-DSB repair mechanisms may contribute to CDT cell resistance. To address this question, we developed a proliferation assay using human cell lines specifically depleted in each of the main DNA repair pathways. Here, we validate the involvement of the two major DSB repair mechanisms, Homologous Recombination and Non Homologous End Joining, in the management of CDT-induced lesions. We show that impairment of single-strand break repair (SSBR), but not nucleotide excision repair, sensitizes cells to CDT, and we explore the interplay of SSBR with the DSB repair mechanisms. Finally, we document the role of the replicative stress response and demonstrate the involvement of the Fanconi Anemia repair pathway in response to CDT. In conclusion, our work indicates that cellular survival to CDT-induced DNA damage involves different repair pathways, in particular SSBR. This reinforces a model where CDT-related genotoxicity primarily involves SSBs rather than DSBs, underlining the importance of cell proliferation during CDT intoxication and pathogenicity.

Published
2016
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11. Genotoxicity of cytolethal distending toxin (cdt) on isogenic human colorectal cell lines: potential promoting effects for colorectal carcinogenesis

Author

J. Dupuy, Laurence Huc, Inge Dormoy, Gladys Mirey, Julien Vignard, Vanessa Graillot, Jerry W. Shay, 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), Prévention et promotion de la cancérogénèse par les aliments (ToxAlim-PPCA), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Recherche Agronomique (INRA)-Université Toulouse III - Paul Sabatier (UT3), King Abdulaziz University, University of Texas Southwestern Medical Center [Dallas], Contaminants & Stress Cellulaire (ToxAlim-COMICS), Génotoxicité & Signalisation (ToxAlim-GS), ANR program [ANR-10-CESA-011], INRA, NASA [NNX15A121G, NNX16AE08G], Huc-Lemarié, Laurence, and Vignard, Julien

Subjects
0301 basic medicine, p53, DNA Repair, Cytolethal distending toxin, Carcinogenesis, [SDV]Life Sciences [q-bio], lcsh:QR1-502, Apoptosis, medicine.disease_cause, lcsh:Microbiology, Malignant transformation, Intestinal mucosa, DNA Breaks, Double-Stranded, Intestinal Mucosa, Original Research, DNA double strand breaks, 3. Good health, Infectious Diseases, KRAS, Colorectal Neoplasms, Microbiology (medical), DNA repair, DNA damage, Adenomatous Polyposis Coli Protein, Bacterial Toxins, Immunology, colorectal cancer, Biology, Microbiology, Proto-Oncogene Proteins p21(ras), 03 medical and health sciences, Cell Line, Tumor, Genetic model, Escherichia coli, medicine, Humans, cytolethal distending toxin, APC, genotoxicity, Epithelial Cells, Cell Cycle Checkpoints, 030104 developmental biology, Carcinogens, Cancer research, sense organs, Tumor Suppressor Protein p53
Abstract

International audience; The composition of the human microbiota influences tumorigenesis, notably in colorectal cancer (CRC). Pathogenic Escherichlacoli possesses a variety of virulent factors, among them the Cytolethal Distending Toxin (CDT). CDT displays dual DNase and phosphatase activities and induces DNA double strand breaks, cell cycle arrest and apoptosis in a broad range of mammalian cells. As CDT could promote malignant transformation, we investigated the cellular outcomes induced by acute and chronic exposures to E. coli CDT in normal human colon epithelial cells (HCECs). Moreover, we conducted a comparative study between isogenic derivatives cell lines of the normal HCECs in order to mimic the mutation of three major genes found in CRC genetic models: APC, KRAS, and TP53. Our results demonstrate that APC and p53 deficient cells showed impaired DNA damage response after CDT exposure, whereas HCECs expressing oncogenic KRAS(V12) were more resistant to CDT. Compared to normal HCECs, the precancerous derivatives exhibit hallmarks of malignant transformation after a chronic exposure to CDT. HCECs defective in APC and p53 showed enhanced anchorage independent growth and genetic instability, assessed by the micronucleus formation assay. In contrast, the ability to grow independently of anchorage was not impacted by CDT chronic exposure in KRAS(V12) HCECs, but micronucleus formation is dramatically increased. Thus, CDT does not initiate CRC by itself, but may have promoting effects in premalignant HCECs, involving different mechanisms in function of the genetic alterations associated to CRC.

Published
2016
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