10 results on '"bezine, Elisabeth"'
Number of results to display per page
Search Results
2. 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
3. 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
4. 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
5. 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, and Mirey, Gladys
- Subjects
- *
EUKARYOTIC cells , *DNA damage , *TOXINS , *MOLECULAR biology - 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. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
6. The bacterial cytolethal distending toxin: A nuclease inducing indirect DNA double-strand breaks into eukaryotic cells
- Author
-
Mirey, Gladys, bezine, Elisabeth, ToxAlim (ToxAlim), 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), 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), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées
- Subjects
[SDV]Life Sciences [q-bio] ,ComputingMilieux_MISCELLANEOUS - Abstract
National audience
- Published
- 2014
7. 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
8. 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
9. 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
10. 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
- Full Text
- View/download PDF
Catalog
Books, media, physical & digital resources
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.