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Genotoxins: The Mechanistic Links between Escherichia coli and Colorectal Cancer. Cancers (Basel) 2023; 15:cancers15041152. [PMID: 36831495 PMCID: PMC9954437 DOI: 10.3390/cancers15041152] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 02/06/2023] [Accepted: 02/09/2023] [Indexed: 02/16/2023] Open
Abstract
Emerging evidence indicates bacterial infections contribute to the formation of cancers. Bacterial genotoxins are effectors that cause DNA damage by introducing single- and double-strand DNA breaks in the host cells. The first bacterial genotoxin cytolethal distending toxin (CDT) was a protein identified in 1987 in a pathogenic strain in Escherichia coli (E. coli) isolated from a young patient. The peptide-polyketide genotoxin colibactin is produced by the phylogenetic group B2 of E. coli. Recently, a protein produced by attaching/effacing (A/E) pathogens, including enteropathogenic and enterohemorrhagic E. coli (EPEC and EHEC) and their murine equivalent Citrobacter rodentium (CR), has been reported as a novel protein genotoxin, being injected via the type III secretion system (T3SS) into host cells and harboring direct DNA digestion activity with a catalytic histidine-aspartic acid dyad. These E. coli-produced genotoxins impair host DNA, which results in senescence or apoptosis of the target cells if the damage is beyond repair. Conversely, host cells can survive and proliferate if the genotoxin-induced DNA damage is not severe enough to kill them. The surviving cells may accumulate genomic instability and acquire malignant traits. This review presents the cellular responses of infection with the genotoxins-producing E. coli and discusses the current knowledge of the tumorigenic potential of these toxins.
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2
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Acid-induced disassembly of the Haemophilus ducreyi cytolethal distending toxin. Biochem Biophys Res Commun 2022; 636:57-63. [DOI: 10.1016/j.bbrc.2022.10.068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 10/19/2022] [Indexed: 11/21/2022]
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3
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Abstract
AB toxins are protein virulence factors secreted by many bacterial pathogens, contributing to the pathogenicity of the cognate bacteria. AB toxins consist of two functionally distinct components: the enzymatic "A" component for pathogenicity and the receptor-binding "B" component for toxin delivery. Consistently, unlike other virulence factors such as effectors, AB toxins do not require additional systems to deliver them to the target host cells. Target host cells are located in the infection site and/or located distantly from infected host cells. The first part of this review discusses the structural and functional features of single-peptide and multiprotein AB toxins in the context of host-microbe interactions, using several well-characterized examples. The second part of this review discusses toxin neutralization strategies, as well as applications of AB toxins relevant to developing intervention strategies against diseases.
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4
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Abstract
Bacterial genotoxins are peptide or protein virulence factors produced by several pathogens, which make single-strand breaks (SSBs) and/or double-strand DNA breaks (DSBs) in the target host cells. If host DNA inflictions are not resolved on time, host cell apoptosis, cell senescence, and/or even bacterial pathogen-related cancer may occur. Two multi-protein AB toxins, cytolethal distending toxin (CDT) produced by over 30 bacterial pathogens and typhoid toxin from Salmonella Typhi, as well as small polyketide-peptides named colibactin that causes the DNA interstrand cross-linking and subsequent DSBs is the most well-characterized bacterial genotoxins. Using these three examples, this review discusses the mechanisms by which these toxins deliver themselves into the nucleus of the target host cells and exert their genotoxic functions at the structural and functional levels.
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Affiliation(s)
- Liaoqi Du
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
| | - Jeongmin Song
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
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5
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Butt S, Gagnon J, Saleh M. A Protective Role for Glucagon-like Peptide-2 in Heat-stable Enterotoxin b (STb)-Induced L-Cell Toxicity. Endocrinology 2022; 163:6546206. [PMID: 35266539 DOI: 10.1210/endocr/bqac029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Indexed: 11/19/2022]
Abstract
Enterotoxigenic Escherichia coli (ETEC)-derived purified heat-stable enterotoxin b (STb) is responsible for secretory diarrhea in livestock and humans. STb disrupts intestinal fluid homeostasis, epithelial barrier function, and promotes cell death. Glucagon-like peptide-2 (GLP-2) is a potent intestinotrophic hormone secreted by enteroendocrine L cells. GLP-2 enhances crypt cell proliferation, epithelial barrier function, and inhibits enterocyte apoptosis. Whether STb can affect GLP-2 producing L cells remains to be elucidated. First, secreted-His-labeled STb from transformed E coli was collected and purified. When incubated with L-cell models (GLUTag, NCI-H716, and secretin tumor cell line [STC-1]), fluorescent immunocytochemistry revealed STb was internalized and was differentially localized in the cytoplasm and nucleus. Cell viability experiments with neutral red and resazurin revealed that STb was toxic in all but the GLUTag cells. STb stimulated 2-hour GLP-2 secretion in all cell models. Interestingly, GLUTag cells produced the highest amount of GLP-2 when treated with STb, demonstrating an inverse relationship in GLP-2 secretion and cell toxicity. To demonstrate a protective role for GLP-2, GLUTag-conditioned media (rich in GLP-2) blocked STb toxicity in STC-1 cells. Confirming a protective role of GLP-2, teduglutide was able to improve cell viability in cells treated with H2O2. In conclusion, STb interacts with the L cell, stimulates secretion, and may induce toxicity if GLP-2 is not produced at high levels. GLP-2 or receptor agonists have the ability to improve cell viability in response to toxins. These results suggest that GLP-2 secretion can play a protective role during STb intoxication. This work supports future investigation into the use of GLP-2 therapies in enterotoxigenic-related diseases.
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Affiliation(s)
- Shahnawaz Butt
- Laurentian University, School of Natural Sciences, Sudbury, Ontario P3E 2C6, Canada
| | - Jeffrey Gagnon
- Laurentian University, School of Natural Sciences, Sudbury, Ontario P3E 2C6, Canada
| | - Mazen Saleh
- Laurentian University, School of Natural Sciences, Sudbury, Ontario P3E 2C6, Canada
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6
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Lai YR, Chang YF, Ma J, Chiu CH, Kuo ML, Lai CH. From DNA Damage to Cancer Progression: Potential Effects of Cytolethal Distending Toxin. Front Immunol 2021; 12:760451. [PMID: 34868002 PMCID: PMC8634426 DOI: 10.3389/fimmu.2021.760451] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 10/21/2021] [Indexed: 12/16/2022] Open
Abstract
Cytolethal distending toxin (CDT), one of the most important genotoxins, is produced by several gram-negative bacteria and is involved in bacterial pathogenesis. Recent studies have shown that bacteria producing this peculiar genotoxin target host DNA, which potentially contributes to development of cancer. In this review, we highlighted the recent studies focusing on the idea that CDT leads to DNA damage, and the cells with inappropriately repaired DNA continue cycling, resulting in cancer development. Understanding the detailed mechanisms of genotoxins that cause DNA damage might be useful for targeting potential markers that drive cancer progression and help to discover new therapeutic strategies to prevent diseases caused by pathogens.
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Affiliation(s)
- Yi-Ru Lai
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yu-Fang Chang
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Jason Ma
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Cheng-Hsun Chiu
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Molecular Infectious Disease Research Center, Department of Pediatrics, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Ming-Ling Kuo
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Division of Allergy, Asthma, and Rheumatology, Department of Pediatrics, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Chih-Ho Lai
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Molecular Infectious Disease Research Center, Department of Pediatrics, Chang Gung Memorial Hospital, Linkou, Taiwan.,Department of Microbiology, School of Medicine, China Medical University, Taichung, Taiwan.,Department of Nursing, Asia University, Taichung, Taiwan
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7
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Cytolethal distending toxin: from genotoxin to a potential biomarker and anti-tumor target. World J Microbiol Biotechnol 2021; 37:150. [PMID: 34379213 DOI: 10.1007/s11274-021-03117-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 07/31/2021] [Indexed: 10/20/2022]
Abstract
Cytolethal Distending Toxin (CDT) belongs to the AB toxin family and is produced by a plethora of Gram-negative bacteria. Eight human-affecting enteropathogens harbor CDT that causes irritable bowel syndrome (IBS), dysentery, chancroid, and periodontitis worldwide. They have a novel molecular mode of action as they interfere in the eukaryotic cell-cycle progression leading to G2/M arrest and apoptosis. CDT, the first bacterial genotoxin described, is encoded in a single operon possessing three proteins, CdtA, CdtB, and CdtC. CdtA and CdtC are needed for the binding of the CDT toxin complex to the cholesterol-rich lipid domains of the host cell while the CdtB is the active moiety. Sequence and 3D structural-based analysis of CdtB showed similarities with nucleases and phosphatases, it was hypothesized that CdtB exercises a biochemical function identical to both these enzymes. CDT is secreted through the outer membrane vesicles from the producing bacteria. It is internalized in the target cells via clathrin-dependent endocytosis and translocated to the host cell nucleus through the Golgi complex and ER. This study discusses the virulence role of CDT, causing pathogenicity by acting as a tri-perditious complex in the CDT-producing species with an emphasis on its potential role as a biomarker and an anti-tumor agent.
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8
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The Role of DNA Damage Response in Dysbiosis-Induced Colorectal Cancer. Cells 2021; 10:cells10081934. [PMID: 34440703 PMCID: PMC8391204 DOI: 10.3390/cells10081934] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/23/2021] [Accepted: 07/23/2021] [Indexed: 12/16/2022] Open
Abstract
The high incidence of colorectal cancer (CRC) in developed countries indicates a predominant role of the environment as a causative factor. Natural gut microbiota provides multiple benefits to humans. Dysbiosis is characterized by an unbalanced microbiota and causes intestinal damage and inflammation. The latter is a common denominator in many cancers including CRC. Indeed, in an inflammation scenario, cellular growth is promoted and immune cells release Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS), which cause DNA damage. Apart from that, many metabolites from the diet are converted into DNA damaging agents by microbiota and some bacteria deliver DNA damaging toxins in dysbiosis conditions as well. The interactions between diet, microbiota, inflammation, and CRC are not the result of a straightforward relationship, but rather a network of multifactorial interactions that deserve deep consideration, as their consequences are not yet fully elucidated. In this paper, we will review the influence of dysbiosis in the induction of DNA damage and CRC.
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9
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Robb Huhn G, Torres-Mangual N, Clore J, Cilenti L, Frisan T, Teter K. Endocytosis of the CdtA subunit from the Haemophilus ducreyi cytolethal distending toxin. Cell Microbiol 2021; 23:e13380. [PMID: 34292647 DOI: 10.1111/cmi.13380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 07/14/2021] [Accepted: 07/16/2021] [Indexed: 12/30/2022]
Abstract
Many Gram-negative pathogens produce a cytolethal distending toxin (CDT) with two cell-binding subunits (CdtA + CdtC) and a catalytic CdtB subunit. After adhesion to the plasma membrane of a target cell, CDT moves by retrograde transport to endoplasmic reticulum. CdtB then enters the nucleus where it generates DNA breaks that lead to cell cycle arrest and apoptosis or senescence. CdtA anchors the CDT holotoxin to the plasma membrane and is thought to remain on the cell surface after endocytosis of the CdtB/CdtC heterodimer. Here, we re-examined the potential endocytosis and intracellular transport of CdtA from the Haemophilus ducreyi CDT. We recorded the endocytosis of holotoxin-associated CdtA with a cell-based enzyme-linked immunoabsorbent assay (CELISA) and visualised its presence in the early endosomes by confocal microscopy 10 min after CDT binding to the cell surface. Western blot analysis documented the rapid degradation of internalised CdtA. Most of internalised CdtB and CdtC were degraded as well. The rapid rate of CDT internalisation and turnover, which could explain why CdtA endocytosis was not detected in previous studies, suggests only a minor pool of cell-associated CdtB reaches the nucleus. Our work demonstrates that CDT is internalised as an intact holotoxin and identifies the endosomes as the site of CdtA dissociation from CdtB/CdtC. TAKE AWAYS: During the endocytosis of CDT, CdtA is thought to remain at the cell surface. A cell-based ELISA documented the rapid endocytosis of CdtA. CdtA was visualised in the early endosomes by confocal microscopy. Intracellular CdtA was rapidly degraded, along with most of CdtB and CdtC.
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Affiliation(s)
- G Robb Huhn
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, USA
| | - Naly Torres-Mangual
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, USA.,Colorado State University, Fort Collins, CO, USA
| | - John Clore
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, USA
| | - Lucia Cilenti
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, USA
| | - Teresa Frisan
- Department of Molecular Biology, Umeå University, Umeå, Sweden.,Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Ken Teter
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, USA
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10
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Host Chromatin Regulators Required for Aggregatibacter actinomycetemcomitans Cytolethal Distending Toxin Activity in Saccharomyces cerevisiae Model. Infect Immun 2021; 89:e0003621. [PMID: 33941581 DOI: 10.1128/iai.00036-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cytolethal distending toxin (CDT) is a bacterial genotoxin that causes host cell cycle arrest and death. We previously employed a Saccharomyces cerevisiae model with inducible expression of the CDT catalytic subunit from Aggregatibacter actinomycetemcomitans, AaCdtB, and showed that a wide variety of host factors play a role in facilitating the activity of CdtB. Our observation that a yeast H2B mutant defective in chromatin condensation was partially resistant to CdtB implies that chromatin structure may affect CDT function. In this study, we identified host chromatin regulatory genes required for CdtB cytotoxicity. We found that the deletion of HTZ1 or certain subunits of SWR, INO80, and SIR complexes increased cellular resistance to CdtB. We hypothesized that CdtB may interact with Htz1 or the chromatin, but immunoprecipitation experiments failed to detect physical interaction between CdtB and Htz1 or the chromatin. However, we observed reduced nuclear localization of CdtB in several mutants, suggesting that impaired nuclear translocation may, at least partly, explain the mechanisms of CdtB resistance. In addition, mutations in chromatin regulatory genes induce changes in the global gene expression profile, and these may indirectly affect CdtB toxicity. Our results suggest that decreased expression of endoplasmic reticulum (ER)-Golgi transport-related genes that may be involved in CdtB transport and/or increased expression of DNA repair genes may contribute to CdtB resistance. These results suggest that the functions of chromatin regulators may contribute to the activity of CDT in host cells.
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11
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Lopez Chiloeches M, Bergonzini A, Frisan T. Bacterial Toxins Are a Never-Ending Source of Surprises: From Natural Born Killers to Negotiators. Toxins (Basel) 2021; 13:426. [PMID: 34204481 PMCID: PMC8235270 DOI: 10.3390/toxins13060426] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 06/07/2021] [Accepted: 06/14/2021] [Indexed: 02/07/2023] Open
Abstract
The idea that bacterial toxins are not only killers but also execute more sophisticated roles during bacteria-host interactions by acting as negotiators has been highlighted in the past decades. Depending on the toxin, its cellular target and mode of action, the final regulatory outcome can be different. In this review, we have focused on two families of bacterial toxins: genotoxins and pore-forming toxins, which have different modes of action but share the ability to modulate the host's immune responses, independently of their capacity to directly kill immune cells. We have addressed their immuno-suppressive effects with the perspective that these may help bacteria to avoid clearance by the host's immune response and, concomitantly, limit detrimental immunopathology. These are optimal conditions for the establishment of a persistent infection, eventually promoting asymptomatic carriers. This immunomodulatory effect can be achieved with different strategies such as suppression of pro-inflammatory cytokines, re-polarization of the immune response from a pro-inflammatory to a tolerogenic state, and bacterial fitness modulation to favour tissue colonization while preventing bacteraemia. An imbalance in each of those effects can lead to disease due to either uncontrolled bacterial proliferation/invasion, immunopathology, or both.
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Affiliation(s)
| | | | - Teresa Frisan
- Department of Molecular Biology and Umeå Centre for Microbial Research (UCMR), Umeå University, 901 87 Umeå, Sweden; (M.L.C.); (A.B.)
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12
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Mathiasen SL, Gall-Mas L, Pateras IS, Theodorou SDP, Namini MRJ, Hansen MB, Martin OCB, Vadivel CK, Ntostoglou K, Butter D, Givskov M, Geisler C, Akbar AN, Gorgoulis VG, Frisan T, Ødum N, Krejsgaard T. Bacterial genotoxins induce T cell senescence. Cell Rep 2021; 35:109220. [PMID: 34107253 DOI: 10.1016/j.celrep.2021.109220] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 02/16/2021] [Accepted: 05/14/2021] [Indexed: 12/11/2022] Open
Abstract
Several types of pathogenic bacteria produce genotoxins that induce DNA damage in host cells. Accumulating evidence suggests that a central function of these genotoxins is to dysregulate the host's immune response, but the underlying mechanisms remain unclear. To address this issue, we investigated the effects of the most widely expressed bacterial genotoxin, the cytolethal distending toxin (CDT), on T cells-the key mediators of adaptive immunity. We show that CDT induces premature senescence in activated CD4 T cells in vitro and provide evidence suggesting that infection with genotoxin-producing bacteria promotes T cell senescence in vivo. Moreover, we demonstrate that genotoxin-induced senescent CD4 T cells assume a senescence-associated secretory phenotype (SASP) which, at least partly, is orchestrated by the ATM-p38 signaling axis. These findings provide insight into the immunomodulatory properties of bacterial genotoxins and uncover a putative link between bacterial infections and T cell senescence.
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Affiliation(s)
- Sarah L Mathiasen
- LEO Foundation Skin Immunology Research Center, Department of Immunology and Microbiology, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Laura Gall-Mas
- LEO Foundation Skin Immunology Research Center, Department of Immunology and Microbiology, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Ioannis S Pateras
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National Kapodistrian University of Athens, 11527 Athens, Greece
| | - Sofia D P Theodorou
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National Kapodistrian University of Athens, 11527 Athens, Greece
| | - Martin R J Namini
- LEO Foundation Skin Immunology Research Center, Department of Immunology and Microbiology, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Morten B Hansen
- Department of Clinical Immunology, Rigshospitalet, Copenhagen University Hospital, 2100 Copenhagen, Denmark
| | - Océane C B Martin
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Chella Krishna Vadivel
- LEO Foundation Skin Immunology Research Center, Department of Immunology and Microbiology, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Konstantinos Ntostoglou
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National Kapodistrian University of Athens, 11527 Athens, Greece
| | - Deborah Butter
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Michael Givskov
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Carsten Geisler
- LEO Foundation Skin Immunology Research Center, Department of Immunology and Microbiology, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Arne N Akbar
- Division of Medicine, University College London, London WC1E 6JF, UK
| | - Vassilis G Gorgoulis
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National Kapodistrian University of Athens, 11527 Athens, Greece; Biomedical Research Foundation of the Academy of Athens, 11527 Athens, Greece; Faculty Institute for Cancer Sciences, Manchester Academic Health Sciences Centre, University of Manchester, Manchester M13 9PL, UK
| | - Teresa Frisan
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden; Department of Molecular Biology and Umeå Center for Microbial Research (UCMR), Umeå University, 90187 Umeå, Sweden
| | - Niels Ødum
- LEO Foundation Skin Immunology Research Center, Department of Immunology and Microbiology, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Thorbjørn Krejsgaard
- LEO Foundation Skin Immunology Research Center, Department of Immunology and Microbiology, University of Copenhagen, 2200 Copenhagen, Denmark.
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13
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Tremblay W, Mompart F, Lopez E, Quaranta M, Bergoglio V, Hashim S, Bonnet D, Alric L, Mas E, Trouche D, Vignard J, Ferrand A, Mirey G, Fernandez-Vidal A. Cytolethal Distending Toxin Promotes Replicative Stress Leading to Genetic Instability Transmitted to Daughter Cells. Front Cell Dev Biol 2021; 9:656795. [PMID: 34026755 PMCID: PMC8138442 DOI: 10.3389/fcell.2021.656795] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/23/2021] [Indexed: 12/30/2022] Open
Abstract
The cytolethal distending toxin (CDT) is produced by several Gram-negative pathogenic bacteria. In addition to inflammation, experimental evidences are in favor of a protumoral role of CDT-harboring bacteria such as Escherichia coli, Campylobacter jejuni, or Helicobacter hepaticus. CDT may contribute to cell transformation in vitro and carcinogenesis in mice models, through the genotoxic action of CdtB catalytic subunit. Here, we investigate the mechanism of action by which CDT leads to genetic instability in human cell lines and colorectal organoids from healthy patients’ biopsies. We demonstrate that CDT holotoxin induces a replicative stress dependent on CdtB. The slowing down of DNA replication occurs mainly in late S phase, resulting in the expression of fragile sites and important chromosomic aberrations. These DNA abnormalities induced after CDT treatment are responsible for anaphase bridge formation in mitosis and interphase DNA bridge between daughter cells in G1 phase. Moreover, CDT-genotoxic potential preferentially affects human cycling cells compared to quiescent cells. Finally, the toxin induces nuclear distension associated to DNA damage in proliferating cells of human colorectal organoids, resulting in decreased growth. Our findings thus identify CDT as a bacterial virulence factor targeting proliferating cells, such as human colorectal progenitors or stem cells, inducing replicative stress and genetic instability transmitted to daughter cells that may therefore contribute to carcinogenesis. As some CDT-carrying bacterial strains were detected in patients with colorectal cancer, targeting these bacteria could be a promising therapeutic strategy.
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Affiliation(s)
- William Tremblay
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Florence Mompart
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Elisa Lopez
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Muriel Quaranta
- IRSD, Université de Toulouse, INSERM, INRAE, ENVT, UPS, Toulouse, France
| | - Valérie Bergoglio
- MCD, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Saleha Hashim
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Delphine Bonnet
- Department of Internale and Digestive Diseases, Pole Digestif, CHU Toulouse, Paul Sabatier University, Toulouse, France
| | - Laurent Alric
- Department of Internale and Digestive Diseases, Pole Digestif, CHU Toulouse, Paul Sabatier University, Toulouse, France
| | - Emmanuel Mas
- IRSD, Université de Toulouse, INSERM, INRAE, ENVT, UPS, Toulouse, France.,Unité de Gastroentérologie, Hépatologie, Nutrition, Diabétologie et Maladies Héréditaires du Métabolisme, Hôpital des Enfants, CHU de Toulouse, Toulouse, France
| | - Didier Trouche
- MCD, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Julien Vignard
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Audrey Ferrand
- IRSD, Université de Toulouse, INSERM, INRAE, ENVT, UPS, Toulouse, France
| | - Gladys Mirey
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Anne Fernandez-Vidal
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, Toulouse, France.,MCD, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, Toulouse, France
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14
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Le LHM, Ying L, Ferrero RL. Nuclear trafficking of bacterial effector proteins. Cell Microbiol 2021; 23:e13320. [PMID: 33600054 DOI: 10.1111/cmi.13320] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 02/06/2023]
Abstract
Bacterial pathogens can subvert host responses by producing effector proteins that directly target the nucleus of eukaryotic cells in animals and plants. Nuclear-targeting proteins are categorised as either: "nucleomodulins," which have epigenetic-modulating activities; or "cyclomodulins," which specifically interfere with the host cell cycle. Bacteria can deliver these effector proteins to eukaryotic cells via a range of strategies. Despite an increasing number of reports describing the effects of bacterial effector proteins on nuclear processes in host cells, the intracellular pathways used by these proteins to traffic to the nucleus have yet to be fully elucidated. This review will describe current knowledge about how nucleomodulins and cyclomodulins enter eukaryotic cells, exploit endocytic pathways and translocate to the nucleus. We will also discuss the secretion of nuclear-targeting proteins or their release in bacterial membrane vesicles and the trafficking pathways employed by each of these forms. Besides their importance for bacterial pathogenesis, some nuclear-targeting proteins have been implicated in the development of chronic diseases and even cancer. A greater understanding of nuclear-targeting proteins and their actions will provide new insights into the pathogenesis of infectious diseases, as well as contribute to advances in the development of novel therapies against bacterial infections and possibly cancer.
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Affiliation(s)
- Lena Hoang My Le
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Biomedicine Discovery Institute, Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Le Ying
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Richard L Ferrero
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Biomedicine Discovery Institute, Department of Microbiology, Monash University, Melbourne, Victoria, Australia.,Department of Molecular and Translational Science, Monash University, Melbourne, Victoria, Australia
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15
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Abstract
Campylobacter jejuni and Campylobacter coli can be frequently isolated from poultry and poultry-derived products, and in combination these two species cause a large portion of human bacterial gastroenteritis cases. While birds are typically colonized by these Campylobacter species without clinical symptoms, in humans they cause (foodborne) infections at high frequencies, estimated to cost billions of dollars worldwide every year. The clinical outcome of Campylobacter infections comprises malaise, diarrhea, abdominal pain and fever. Symptoms may continue for up to two weeks and are generally self-limiting, though occasionally the disease can be more severe or result in post-infection sequelae. The virulence properties of these pathogens have been best-characterized for C. jejuni, and their actions are reviewed here. Various virulence-associated bacterial determinants include the flagellum, numerous flagellar secreted factors, protein adhesins, cytolethal distending toxin (CDT), lipooligosaccharide (LOS), serine protease HtrA and others. These factors are involved in several pathogenicity-linked properties that can be divided into bacterial chemotaxis, motility, attachment, invasion, survival, cellular transmigration and spread to deeper tissue. All of these steps require intimate interactions between bacteria and host cells (including immune cells), enabled by the collection of bacterial and host factors that have already been identified. The assortment of pathogenicity-associated factors now recognized for C. jejuni, their function and the proposed host cell factors that are involved in crucial steps leading to disease are discussed in detail.
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16
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Pons BJ, Loiseau N, Hashim S, Tadrist S, Mirey G, Vignard J. Functional Study of Haemophilus ducreyi Cytolethal Distending Toxin Subunit B. Toxins (Basel) 2020; 12:toxins12090530. [PMID: 32825080 PMCID: PMC7551728 DOI: 10.3390/toxins12090530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 08/13/2020] [Accepted: 08/17/2020] [Indexed: 12/17/2022] Open
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.
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Affiliation(s)
| | | | | | | | - Gladys Mirey
- Correspondence: (G.M.); (J.V.); Tel.: +33-582-066-338 (G.M.)
| | - Julien Vignard
- Correspondence: (G.M.); (J.V.); Tel.: +33-582-066-338 (G.M.)
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17
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Boesze-Battaglia K, Dhingra A, Walker LM, Zekavat A, Shenker BJ. Internalization and Intoxication of Human Macrophages by the Active Subunit of the Aggregatibacter actinomycetemcomitans Cytolethal Distending Toxin Is Dependent Upon Cellugyrin (Synaptogyrin-2). Front Immunol 2020; 11:1262. [PMID: 32655562 PMCID: PMC7325893 DOI: 10.3389/fimmu.2020.01262] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 05/18/2020] [Indexed: 12/20/2022] Open
Abstract
The Aggregatibacter actinomycetemcomitans cytolethal distending toxin (Cdt) is a heterotrimeric AB2 toxin capable of inducing cell cycle arrest and apoptosis in lymphocytes and other cell types. Recently, we have demonstrated that human macrophages are resistant to Cdt-induced apoptosis but are susceptible to toxin-induced pro-inflammatory cytokine response involving activation of the NLRP3 inflammasome. Exposure to Cdt results in binding to the cell surface followed by internalization and translocation of the active subunit, CdtB, to intracellular compartments. Internalization involves hijacking of retrograde pathways; treatment of cells with Retro-2 leads to a decrease in CdtB-Golgi association. These events are dependent upon toxin binding to cholesterol in the context of lipid rich membrane microdomains often referred to as lipid rafts. We now demonstrate that within 1 h of exposure of macrophages to Cdt, CdtB is internalized and found primarily within lipid rafts; concurrently, cellugyrin (synaptogyrin-2) also translocates into lipid rafts. Further analysis by immunoprecipitation indicates that CdtB associates with complexes containing both cellugyrin and Derlin-2. Moreover, a human macrophage cell line deficient in cellugyrin expression (THP-1Cg-) challenged with Cdt failed to internalize CdtB and was resistant to the Cdt-induced pro-inflammatory response. We propose that lipid rafts along with cellugyrin play a critical role in the internalization and translocation of CdtB to critical intracellular target sites in human macrophages. These studies provide the first evidence that cellugyrin is expressed in human macrophages and plays a critical role in Cdt toxicity of these cells.
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Affiliation(s)
- Kathleen Boesze-Battaglia
- Department of Biochemistry, University of Pennsylvania School of Dental Medicine, Philadelphia, PA, United States
| | - Anuradha Dhingra
- Department of Biochemistry, University of Pennsylvania School of Dental Medicine, Philadelphia, PA, United States
| | - Lisa M Walker
- Department of Pathology, University of Pennsylvania School of Dental Medicine, Philadelphia, PA, United States
| | - Ali Zekavat
- Department of Pathology, University of Pennsylvania School of Dental Medicine, Philadelphia, PA, United States
| | - Bruce J Shenker
- Department of Pathology, University of Pennsylvania School of Dental Medicine, Philadelphia, PA, United States
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18
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Silbergleit M, Vasquez AA, Miller CJ, Sun J, Kato I. Oral and intestinal bacterial exotoxins: Potential linked to carcinogenesis. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 171:131-193. [PMID: 32475520 DOI: 10.1016/bs.pmbts.2020.02.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Growing evidence suggests that imbalances in resident microbes (dysbiosis) can promote chronic inflammation, immune-subversion, and production of carcinogenic metabolites, thus leading to neoplasia. Yet, evidence to support a direct link of individual bacteria species to human sporadic cancer is still limited. This chapter focuses on several emerging bacterial toxins that have recently been characterized for their potential oncogenic properties toward human orodigestive cancer and the presence of which in human tissue samples has been documented. These include cytolethal distending toxins produced by various members of gamma and epsilon Proteobacteria, Dentilisin from mammalian oral Treponema, Pasteurella multocida toxin, two Fusobacterial toxins, FadA and Fap2, Bacteroides fragilis toxin, colibactin, cytotoxic necrotizing factors and α-hemolysin from Escherichia coli, and Salmonella enterica AvrA. It was clear that these bacterial toxins have biological activities to induce several hallmarks of cancer. Some toxins directly interact with DNA or chromosomes leading to their breakdowns, causing mutations and genome instability, and others modulate cell proliferation, replication and death and facilitate immune evasion and tumor invasion, prying specific oncogene and tumor suppressor pathways, such as p53 and β-catenin/Wnt. In addition, most bacterial toxins control tumor-promoting inflammation in complex and diverse mechanisms. Despite growing laboratory evidence to support oncogenic potential of selected bacterial toxins, we need more direct evidence from human studies and mechanistic data from physiologically relevant experimental animal models, which can reflect chronic infection in vivo, as well as take bacterial-bacterial interactions among microbiome into consideration.
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Affiliation(s)
| | - Adrian A Vasquez
- Department of Civil and Environmental Engineering, Wayne State University, Healthy Urban Waters, Detroit, MI, United States
| | - Carol J Miller
- Department of Civil and Environmental Engineering, Wayne State University, Healthy Urban Waters, Detroit, MI, United States
| | - Jun Sun
- Department of Medicine, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States
| | - Ikuko Kato
- Department of Oncology, Wayne State University School of Medicine, Detroit, MI, United States; Department of Pathology, Wayne State University School of Medicine, Detroit, MI, United States.
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19
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Shenker BJ, Walker LM, Zekavat Z, Ojcius DM, Huang PR, Boesze-Battaglia K. Cytolethal distending toxin-induced release of interleukin-1β by human macrophages is dependent upon activation of glycogen synthase kinase 3β, spleen tyrosine kinase (Syk) and the noncanonical inflammasome. Cell Microbiol 2020; 22:e13194. [PMID: 32068949 DOI: 10.1111/cmi.13194] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 01/09/2020] [Accepted: 01/24/2020] [Indexed: 12/19/2022]
Abstract
Cytolethal distending toxins (Cdt) are a family of toxins produced by several human pathogens which infect mucocutaneous tissue and induce inflammatory disease. We have previously demonstrated that the Aggregatibacter actinomycetemcomitans Cdt induces a pro-inflammatory response from human macrophages which involves activation of the NLRP3 inflammasome. We now demonstrate that in addition to activating caspase-1 (canonical inflammasome), Cdt treatment leads to caspase-4 activation and involvement of the noncanonical inflammasome. Cdt-treated cells exhibit pyroptosis characterised by cleavage of gasdermin-D (GSDMD), release of HMGB1 at 24 hr and LDH at 48 hr. Inhibition of either the canonical (caspase-1) or noncanonical (caspase-4) inflammasome blocks both Cdt-induced release of IL-1β and induction of pyroptosis. Analysis of upstream events indicates that Cdt induces Syk phosphorylation (activation); furthermore, blockade of Syk expression and inhibition of pSyk activity inhibit both Cdt-induced cytokine release and pyroptosis. Finally, we demonstrate that increases in pSyk are dependent upon Cdt-induced activation of GSK3β. These studies advance our understanding of Cdt function and provide new insight into the virulence potential of Cdt in mediating the pathogenesis of disease caused by Cdt-producing organisms such as A. actinomycetemcomitans.
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Affiliation(s)
- Bruce J Shenker
- Department of Pathology, University of Pennsylvania School of Dental Medicine, Philadelphia, Pennsylvania, USA
| | - Lisa M Walker
- Department of Pathology, University of Pennsylvania School of Dental Medicine, Philadelphia, Pennsylvania, USA
| | - Zeyed Zekavat
- Department of Pathology, University of Pennsylvania School of Dental Medicine, Philadelphia, Pennsylvania, USA
| | - David M Ojcius
- Department of Biomedical Sciences, University of the Pacific Arthur A. Dugoni School of Dentistry, San Francisco, California, USA
| | - Pei-Rong Huang
- Center for Molecular and Clinical Immunology, Chang Gung University, Taoyuan, Taiwan
| | - Kathleen Boesze-Battaglia
- Department of Biochemistry, University of Pennsylvania School of Dental Medicine, Philadelphia, Pennsylvania, USA
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20
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In Silico Design and Evaluation of scFv-CdtB as a Novel Immunotoxin for Breast Cancer Treatment. INTERNATIONAL JOURNAL OF CANCER MANAGEMENT 2020. [DOI: 10.5812/ijcm.96094] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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21
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Cytolethal Distending Toxin Subunit B: A Review of Structure-Function Relationship. Toxins (Basel) 2019; 11:toxins11100595. [PMID: 31614800 PMCID: PMC6832162 DOI: 10.3390/toxins11100595] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 10/08/2019] [Accepted: 10/09/2019] [Indexed: 01/27/2023] Open
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.
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22
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Martin OCB, Bergonzini A, D'Amico F, Chen P, Shay JW, Dupuy J, Svensson M, Masucci MG, Frisan T. Infection with genotoxin-producing Salmonella enterica synergises with loss of the tumour suppressor APC in promoting genomic instability via the PI3K pathway in colonic epithelial cells. Cell Microbiol 2019; 21:e13099. [PMID: 31414579 PMCID: PMC6899655 DOI: 10.1111/cmi.13099] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/16/2019] [Accepted: 07/30/2019] [Indexed: 12/18/2022]
Abstract
Several commensal and pathogenic Gram‐negative bacteria produce DNA‐damaging toxins that are considered bona fide carcinogenic agents. The microbiota of colorectal cancer (CRC) patients is enriched in genotoxin‐producing bacteria, but their role in the pathogenesis of CRC is poorly understood. The adenomatous polyposis coli (APC) gene is mutated in familial adenomatous polyposis and in the majority of sporadic CRCs. We investigated whether the loss of APC alters the response of colonic epithelial cells to infection by Salmonella enterica, the only genotoxin‐producing bacterium associated with cancer in humans. Using 2D and organotypic 3D cultures, we found that APC deficiency was associated with sustained activation of the DNA damage response, reduced capacity to repair different types of damage, including DNA breaks and oxidative damage, and failure to induce cell cycle arrest. The reduced DNA repair capacity and inability to activate adequate checkpoint responses was associated with increased genomic instability in APC‐deficient cells exposed to the genotoxic bacterium. Inhibition of the checkpoint response was dependent on activation of the phosphatidylinositol 3‐kinase pathway. These findings highlight the synergistic effect of the loss of APC and infection with genotoxin‐producing bacteria in promoting a microenvironment conducive to malignant transformation.
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Affiliation(s)
- Océane C B Martin
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Anna Bergonzini
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.,Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Federica D'Amico
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Puran Chen
- Department of Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Jerry W Shay
- Department of Cell Biology, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Jacques Dupuy
- INRA, ToxAlim (Research Centre in Food Toxicology), INRA, ENVT, INP-Purpan, UPS, Université de Toulouse, Toulouse, France
| | - Mattias Svensson
- Department of Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Maria G Masucci
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Teresa Frisan
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.,Department of Molecular Biology, Umeå University, Umeå, Sweden
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23
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Denmongkholchai S, Katare P, Choochuay S, Thanyasrisung P, Tsuruda K, Sugai M, Mongkolsuk S, Matangkasombut O. Genome-Wide Identification of Host Genes Required for Toxicity of Bacterial Cytolethal Distending Toxin in a Yeast Model. Front Microbiol 2019; 10:890. [PMID: 31080443 PMCID: PMC6497811 DOI: 10.3389/fmicb.2019.00890] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 04/08/2019] [Indexed: 12/16/2022] Open
Abstract
Background Aggregatibacter actinomycetemcomitans, a periodontal pathogen, secretes a cytolethal distending toxin (AaCDT) that causes host cell cycle arrest and cell death. Although CDT could be an important virulence factor, it is unclear how it enters the nucleus to exert its cytotoxicity. Objective To investigate the mechanisms of AaCDT by genome-wide screening for host mutations that confer resistance to the catalytic subunit, AaCdtB, in a Saccharomyces cerevisiae model. Methods We transformed the yeast haploid deletion library, a collection of yeast mutants with single gene deletions of virtually all non-essential ORFs in the genome, with plasmids carrying galactose-inducible AaCdtB. Yeast mutants that showed resistance to AaCdtB were selected and rescreened by a spotting assay. AaCdtB expression was confirmed by western blot analysis; any mutants that showed no or weak expression of AaCdtB were omitted from the analysis. The lists of genes whose mutations confer resistance to AaCdtB were analyzed for Gene Ontology (GO) term enrichments. Localization of AaCdtB-EGFP was examined using fluorescent microscopy. Nuclear localization relative to EGFP control was calculated and compared to wild-type. Results Out of approximately 5,000 deletion mutants, we isolated 243 mutants that are resistant to AaCdtB. GO analyses indicated that genes associated with organic anion transport are significantly enriched (16 genes). Furthermore, several genes associated with the nucleus and endoplasmic reticulum (ER) were identified. Localization studies of AaCdtB, in mutants with the deletion of genes associated with the GO term organic anion transport, showed lower nuclear localization than wild-type. The results suggest that these genes may be required for AaCdtB translocation into the nucleus and its cytotoxicity. Conclusion The genome-wide screen in the yeast deletion library allowed us to identify a large number of host genes required for AaCdtB cytotoxicity. Further investigation could lead to more insights into the mechanisms of CdtB intoxication.
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Affiliation(s)
- Siriyod Denmongkholchai
- Interdepartmental Program in Medical Microbiology, Graduate School, Chulalongkorn University, Bangkok, Thailand.,Department of Microbiology and Research Unit on Oral Microbiology and Immunology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - Prashant Katare
- Department of Microbiology and Research Unit on Oral Microbiology and Immunology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand.,Graduate Program in Oral Biology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - Sarocha Choochuay
- Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, Thailand
| | - Panida Thanyasrisung
- Department of Microbiology and Research Unit on Oral Microbiology and Immunology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - Keiko Tsuruda
- Department of Oral Epidemiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Motoyuki Sugai
- Department of Antimicrobial Resistance, Graduate School of Biomedical and Health Sciences, Project Research Center for Nosocomial Infectious Diseases (RCNID), Hiroshima University, Hiroshima, Japan.,Antimicrobial Resistance Research Center, National Institute of Infectious Diseases (NIID), Tokyo, Japan
| | - Skorn Mongkolsuk
- Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, Thailand
| | - Oranart Matangkasombut
- Department of Microbiology and Research Unit on Oral Microbiology and Immunology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand.,Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, Thailand
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24
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Nowakowska-Gołacka J, Sominka H, Sowa-Rogozińska N, Słomińska-Wojewódzka M. Toxins Utilize the Endoplasmic Reticulum-Associated Protein Degradation Pathway in Their Intoxication Process. Int J Mol Sci 2019; 20:E1307. [PMID: 30875878 PMCID: PMC6471375 DOI: 10.3390/ijms20061307] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 03/08/2019] [Accepted: 03/10/2019] [Indexed: 12/25/2022] Open
Abstract
Several bacterial and plant AB-toxins are delivered by retrograde vesicular transport to the endoplasmic reticulum (ER), where the enzymatically active A subunit is disassembled from the holotoxin and transported to the cytosol. In this process, toxins subvert the ER-associated degradation (ERAD) pathway. ERAD is an important part of cellular regulatory mechanism that targets misfolded proteins to the ER channels, prior to their retrotranslocation to the cytosol, ubiquitination and subsequent degradation by a protein-degrading complex, the proteasome. In this article, we present an overview of current understanding of the ERAD-dependent transport of AB-toxins to the cytosol. We describe important components of ERAD and discuss their significance for toxin transport. Toxin recognition and disassembly in the ER, transport through ER translocons and finally cytosolic events that instead of overall proteasomal degradation provide proper folding and cytotoxic activity of AB-toxins are discussed as well. We also comment on recent reports presenting medical applications for toxin transport through the ER channels.
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Affiliation(s)
- Jowita Nowakowska-Gołacka
- Department of Medical Biology and Genetics, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, Poland.
| | - Hanna Sominka
- Department of Medical Biology and Genetics, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, Poland.
| | - Natalia Sowa-Rogozińska
- Department of Medical Biology and Genetics, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, Poland.
| | - Monika Słomińska-Wojewódzka
- Department of Medical Biology and Genetics, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, Poland.
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25
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Frisan T, Nagy N, Chioureas D, Terol M, Grasso F, Masucci MG. A bacterial genotoxin causes virus reactivation and genomic instability in Epstein-Barr virus infected epithelial cells pointing to a role of co-infection in viral oncogenesis. Int J Cancer 2018; 144:98-109. [PMID: 29978480 PMCID: PMC6587852 DOI: 10.1002/ijc.31652] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 05/10/2018] [Accepted: 06/07/2018] [Indexed: 12/11/2022]
Abstract
We have addressed the role of bacterial co‐infection in viral oncogenesis using as model Epstein–Barr virus (EBV), a human herpesvirus that causes lymphoid malignancies and epithelial cancers. Infection of EBV carrying epithelial cells with the common oral pathogenic Gram‐negative bacterium Aggregatibacter actinomycetemcomitans (Aa) triggered reactivation of the productive virus cycle. Using isogenic Aa strains that differ in the production of the cytolethal distending toxin (CDT) and purified catalytically active or inactive toxin, we found that the CDT acts via induction of DNA double strand breaks and activation of the Ataxia Telangectasia Mutated (ATM) kinase. Exposure of EBV‐negative epithelial cells to the virus in the presence of sub‐lethal doses of CDT was accompanied by the accumulation of latently infected cells exhibiting multiple signs of genomic instability. These findings illustrate a scenario where co‐infection with certain bacterial species may favor the establishment of a microenvironment conducive to the EBV‐induced malignant transformation of epithelial cells. What's new? Little is known about the influence of coinfections, especially of bacteria, on viral oncogenesis. Here, the authors examined the effect of the cytolethal distending toxin (CDT) of Aggregatibacter actinomycetemcomitans, a common oral pathogen, on epithelial cells infected with Epstein–Barr virus (EBV). Exposure of EBV+ cells to CDT induced viral reactivation, while exposure of EBV‐ cells to low amounts of CDT led to the accumulation of latently infected cells upon infection, pointing to a multi‐layered role of bacterial co‐infection in viral oncogenesis.
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Affiliation(s)
- Teresa Frisan
- Department of Cell and Molecular Biology Karolinska Institutet, Stockholm, Sweden.,Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Noemi Nagy
- Department of Cell and Molecular Biology Karolinska Institutet, Stockholm, Sweden
| | - Dimitrios Chioureas
- Department of Cell and Molecular Biology Karolinska Institutet, Stockholm, Sweden
| | - Marie Terol
- Department of Cell and Molecular Biology Karolinska Institutet, Stockholm, Sweden
| | - Francesca Grasso
- Department of Cell and Molecular Biology Karolinska Institutet, Stockholm, Sweden
| | - Maria G Masucci
- Department of Cell and Molecular Biology Karolinska Institutet, Stockholm, Sweden
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26
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Hartmann S, Lopez Cruz R, Alameh S, Ho CLC, Rabideau A, Pentelute BL, Bradley KA, Martchenko M. Characterization of Novel Piperidine-Based Inhibitor of Cathepsin B-Dependent Bacterial Toxins and Viruses. ACS Infect Dis 2018; 4:1235-1245. [PMID: 29749721 DOI: 10.1021/acsinfecdis.8b00053] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Exploiting the host endocytic trafficking pathway is a common mechanism by which bacterial exotoxins gain entry to exert virulent effects upon the host cells. A previous study identified a small-molecule, 1-(2,6-dimethyl-1-piperidinyl)-3-[(2-isopropyl-5-methylcyclohexyl)oxy]-2-propanol, that blocks the process of anthrax lethal toxin (LT) cytotoxicity. Here, we report the characterization of the bioactivity of this compound, which we named RC1. We found that RC1 protected host cells independently of LT concentration and also blocked intoxication by other bacterial exotoxins, suggesting that the target of the compound is a host factor. Using the anthrax LT intoxication pathway as a reference, we show that while anthrax toxin is able to bind to cells and establish an endosomal pore in the presence of the drug, the toxin is unable to translocate into the cytosol. We demonstrate that RC1 does not inhibit the toxin directly but rather reduces the enzymatic activity of host cathepsin B that mediates the escape of toxins into the cytoplasm from late endosomes. We demonstrate that the pathogenicity of Human cytomegalovirus and Herpes simplex virus 1, which relies on cathepsin B protease activity, is reduced by RC1. This study reveals the potential of RC1 as a broad-spectrum host-oriented therapy against several aggressive and deadly pathogens.
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Affiliation(s)
- Stella Hartmann
- School of Applied Life Sciences, Keck Graduate Institute, 535 Watson Drive, Claremont, California 91711, United States
| | - Renae Lopez Cruz
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, 609 Charles E Young Drive East, Los Angeles, California 90095, United States
| | - Saleem Alameh
- School of Applied Life Sciences, Keck Graduate Institute, 535 Watson Drive, Claremont, California 91711, United States
| | - Chi-Lee C. Ho
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, 609 Charles E Young Drive East, Los Angeles, California 90095, United States
| | - Amy Rabideau
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Bradley L. Pentelute
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Kenneth A. Bradley
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, 609 Charles E Young Drive East, Los Angeles, California 90095, United States
| | - Mikhail Martchenko
- School of Applied Life Sciences, Keck Graduate Institute, 535 Watson Drive, Claremont, California 91711, United States
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Boesze-Battaglia K, Walker LP, Dhingra A, Kandror K, Tang HY, Shenker BJ. Internalization of the Active Subunit of the Aggregatibacter actinomycetemcomitans Cytolethal Distending Toxin Is Dependent upon Cellugyrin (Synaptogyrin 2), a Host Cell Non-Neuronal Paralog of the Synaptic Vesicle Protein, Synaptogyrin 1. Front Cell Infect Microbiol 2017; 7:469. [PMID: 29184850 PMCID: PMC5694546 DOI: 10.3389/fcimb.2017.00469] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 10/25/2017] [Indexed: 12/17/2022] Open
Abstract
The Aggregatibacter actinomycetemcomitans cytolethal distending toxin (Cdt) is a heterotrimeric AB2 toxin capable of inducing lymphocytes, and other cell types, to undergo cell cycle arrest and apoptosis. Exposure to Cdt results in binding to the cell surface followed by internalization and translocation of the active subunit, CdtB, to intracellular compartments. These events are dependent upon toxin binding to cholesterol in the context of lipid rich membrane microdomains often referred to as lipid rafts. We now demonstrate that, in addition to binding to the plasma membrane of lymphocytes, another early and critical event initiated by Cdt is the translocation of the host cell protein, cellugyrin (synaptogyrin-2) to the same cholesterol-rich microdomains. Furthermore, we demonstrate that cellugyrin is an intracellular binding partner for CdtB as demonstrated by immunoprecipitation. Using CRISPR/cas9 gene editing we established a Jurkat cell line deficient in cellugyrin expression (JurkatCg−); these cells were capable of binding Cdt, but unable to internalize CdtB. Furthermore, JurkatCg− cells were not susceptible to Cdt-induced toxicity; these cells failed to exhibit blockade of the PI-3K signaling pathway, cell cycle arrest or cell death. We propose that cellugyrin plays a critical role in the internalization and translocation of CdtB to critical intracellular target sites. These studies provide critical new insight into the mechanism by which Cdt, and in particular, CdtB is able to induce toxicity.
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Affiliation(s)
- Kathleen Boesze-Battaglia
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Lisa P Walker
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Anuradha Dhingra
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Konstantin Kandror
- Department of Biochemistry, School of Medicine, Boston University, Boston, MA, United States
| | - Hsin-Yao Tang
- Wistar Proteomics and Metabolomics Core Facility, Wistar Institute, Philadelphia, PA, United States
| | - Bruce J Shenker
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, United States
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AKT2 suppresses pro-survival autophagy triggered by DNA double-strand breaks in colorectal cancer cells. Cell Death Dis 2017; 8:e3019. [PMID: 28837154 PMCID: PMC5596597 DOI: 10.1038/cddis.2017.418] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 07/18/2017] [Accepted: 07/20/2017] [Indexed: 12/12/2022]
Abstract
DNA double-strand breaks (DSBs) are critical DNA lesions, which threaten genome stability and cell survival. DSBs are directly induced by ionizing radiation (IR) and radiomimetic agents, including the cytolethal distending toxin (CDT). This bacterial genotoxin harbors a unique DNase-I-like endonuclease activity. Here we studied the role of DSBs induced by CDT and IR as a trigger of autophagy, which is a cellular degradation process involved in cell homeostasis, genome protection and cancer. The regulatory mechanisms of DSB-induced autophagy were analyzed, focusing on the ATM-p53-mediated DNA damage response and AKT signaling in colorectal cancer cells. We show that treatment of cells with CDT or IR increased the levels of the autophagy marker LC3B-II. Consistently, an enhanced formation of autophagosomes and a decrease of the autophagy substrate p62 were observed. Both CDT and IR concomitantly suppressed mTOR signaling and stimulated the autophagic flux. DSBs were demonstrated as the primary trigger of autophagy using a DNase I-defective CDT mutant, which neither induced DSBs nor autophagy. Genetic abrogation of p53 and inhibition of ATM signaling impaired the autophagic flux as revealed by LC3B-II accumulation and reduced formation of autophagic vesicles. Blocking of DSB-induced apoptotic cell death by the pan-caspase inhibitor Z-VAD stimulated autophagy. In line with this, pharmacological inhibition of autophagy increased cell death, while ATG5 knockdown did not affect cell death after DSB induction. Interestingly, both IR and CDT caused AKT activation, which repressed DSB-triggered autophagy independent of the cellular DNA-PK status. Further knockdown and pharmacological inhibitor experiments provided evidence that the negative autophagy regulation was largely attributable to AKT2. Finally, we show that upregulation of CDT-induced autophagy upon AKT inhibition resulted in lower apoptosis and increased cell viability. Collectively, the findings demonstrate that DSBs trigger pro-survival autophagy in an ATM- and p53-dependent manner, which is curtailed by AKT2 signaling.
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29
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El-Aouar Filho RA, Nicolas A, De Paula Castro TL, Deplanche M, De Carvalho Azevedo VA, Goossens PL, Taieb F, Lina G, Le Loir Y, Berkova N. Heterogeneous Family of Cyclomodulins: Smart Weapons That Allow Bacteria to Hijack the Eukaryotic Cell Cycle and Promote Infections. Front Cell Infect Microbiol 2017; 7:208. [PMID: 28589102 PMCID: PMC5440457 DOI: 10.3389/fcimb.2017.00208] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 05/09/2017] [Indexed: 12/13/2022] Open
Abstract
Some bacterial pathogens modulate signaling pathways of eukaryotic cells in order to subvert the host response for their own benefit, leading to successful colonization and invasion. Pathogenic bacteria produce multiple compounds that generate favorable conditions to their survival and growth during infection in eukaryotic hosts. Many bacterial toxins can alter the cell cycle progression of host cells, impairing essential cellular functions and impeding host cell division. This review summarizes current knowledge regarding cyclomodulins, a heterogeneous family of bacterial effectors that induce eukaryotic cell cycle alterations. We discuss the mechanisms of actions of cyclomodulins according to their biochemical properties, providing examples of various cyclomodulins such as cycle inhibiting factor, γ-glutamyltranspeptidase, cytolethal distending toxins, shiga toxin, subtilase toxin, anthrax toxin, cholera toxin, adenylate cyclase toxins, vacuolating cytotoxin, cytotoxic necrotizing factor, Panton-Valentine leukocidin, phenol soluble modulins, and mycolactone. Special attention is paid to the benefit provided by cyclomodulins to bacteria during colonization of the host.
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Affiliation(s)
- Rachid A El-Aouar Filho
- STLO, Agrocampus Ouest Rennes, Institut National de la Recherche AgronomiqueRennes, France.,Departamento de Biologia Geral, Laboratório de Genética Celular e Molecular (LGCM), Instituto de Ciências Biológicas, Universidade Federal de Minas GeraisBelo Horizonte, Brazil
| | - Aurélie Nicolas
- STLO, Agrocampus Ouest Rennes, Institut National de la Recherche AgronomiqueRennes, France
| | - Thiago L De Paula Castro
- Departamento de Biologia Geral, Laboratório de Genética Celular e Molecular (LGCM), Instituto de Ciências Biológicas, Universidade Federal de Minas GeraisBelo Horizonte, Brazil
| | - Martine Deplanche
- STLO, Agrocampus Ouest Rennes, Institut National de la Recherche AgronomiqueRennes, France
| | - Vasco A De Carvalho Azevedo
- Departamento de Biologia Geral, Laboratório de Genética Celular e Molecular (LGCM), Instituto de Ciências Biológicas, Universidade Federal de Minas GeraisBelo Horizonte, Brazil
| | - Pierre L Goossens
- HistoPathologie et Modèles Animaux/Pathogénie des Toxi-Infections Bactériennes, Institut PasteurParis, France
| | - Frédéric Taieb
- CHU Purpan USC INRA 1360-CPTP, U1043 Institut National de la Santé et de la Recherche Médicale, Pathogénie Moléculaire et Cellulaire des Infections à Escherichia coliToulouse, France
| | - Gerard Lina
- International Center for Infectiology ResearchLyon, France.,Centre National de la Recherche Scientifique, UMR5308, Institut National de la Santé et de la Recherche Médicale U1111, Ecole Normale Supérieure de Lyon, Université Lyon 1Lyon, France.,Département de Biologie, Institut des Agents Infectieux, Hospices Civils de LyonLyon, France
| | - Yves Le Loir
- STLO, Agrocampus Ouest Rennes, Institut National de la Recherche AgronomiqueRennes, France
| | - Nadia Berkova
- STLO, Agrocampus Ouest Rennes, Institut National de la Recherche AgronomiqueRennes, France
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Bielaszewska M, Rüter C, Bauwens A, Greune L, Jarosch KA, Steil D, Zhang W, He X, Lloubes R, Fruth A, Kim KS, Schmidt MA, Dobrindt U, Mellmann A, Karch H. Host cell interactions of outer membrane vesicle-associated virulence factors of enterohemorrhagic Escherichia coli O157: Intracellular delivery, trafficking and mechanisms of cell injury. PLoS Pathog 2017; 13:e1006159. [PMID: 28158302 PMCID: PMC5310930 DOI: 10.1371/journal.ppat.1006159] [Citation(s) in RCA: 123] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Revised: 02/15/2017] [Accepted: 12/30/2016] [Indexed: 01/15/2023] Open
Abstract
Outer membrane vesicles (OMVs) are important tools in bacterial virulence but their role in the pathogenesis of infections caused by enterohemorrhagic Escherichia coli (EHEC) O157, the leading cause of life-threatening hemolytic uremic syndrome, is poorly understood. Using proteomics, electron and confocal laser scanning microscopy, immunoblotting, and bioassays, we investigated OMVs secreted by EHEC O157 clinical isolates for virulence factors cargoes, interactions with pathogenetically relevant human cells, and mechanisms of cell injury. We demonstrate that O157 OMVs carry a cocktail of key virulence factors of EHEC O157 including Shiga toxin 2a (Stx2a), cytolethal distending toxin V (CdtV), EHEC hemolysin, and flagellin. The toxins are internalized by cells via dynamin-dependent endocytosis of OMVs and differentially separate from vesicles during intracellular trafficking. Stx2a and CdtV-B, the DNase-like CdtV subunit, separate from OMVs in early endosomes. Stx2a is trafficked, in association with its receptor globotriaosylceramide within detergent-resistant membranes, to the Golgi complex and the endoplasmic reticulum from where the catalytic Stx2a A1 fragment is translocated to the cytosol. CdtV-B is, after its retrograde transport to the endoplasmic reticulum, translocated to the nucleus to reach DNA. CdtV-A and CdtV-C subunits remain OMV-associated and are sorted with OMVs to lysosomes. EHEC hemolysin separates from OMVs in lysosomes and targets mitochondria. The OMV-delivered CdtV-B causes cellular DNA damage, which activates DNA damage responses leading to G2 cell cycle arrest. The arrested cells ultimately die of apoptosis induced by Stx2a and CdtV via caspase-9 activation. By demonstrating that naturally secreted EHEC O157 OMVs carry and deliver into cells a cocktail of biologically active virulence factors, thereby causing cell death, and by performing first comprehensive analysis of intracellular trafficking of OMVs and OMV-delivered virulence factors, we provide new insights into the pathogenesis of EHEC O157 infections. Our data have implications for considering O157 OMVs as vaccine candidates. Enterohemorrhagic Escherichia coli (EHEC) O157, the leading EHEC group causing diarrhea and the life-threatening hemolytic uremic syndrome in humans, produce several virulence factors which play distinct roles in the pathogenesis of these diseases. However, the mechanisms of their secretion and host cell injury are poorly understood. We show here that EHEC O157 strains isolated from patients shed nanostructures termed outer membrane vesicles (OMVs) which contain major EHEC O157 virulence factors including Shiga toxin 2a (Stx2a), cytolethal distending toxin V (CdtV), EHEC hemolysin, and flagellin. The OMVs are taken up by human intestinal epithelial and renal and brain microvascular endothelial cells, which are the major targets during EHEC O157 infections, and deliver the virulence factors intracellularly. Inside cells the virulence factors separate from OMVs and are transported via different pathways to their target compartments including the cytosol (Stx2a), nucleus (CdtV-B subunit), and mitochondria (EHEC hemolysin). Cells exposed to EHEC O157 OMVs develop G2 cell cycle arrest induced by CdtV-B-mediated DNA damage. This is followed by apoptotic cell death triggered by Stx2a and CdtV via caspase-9 activation. OMVs thus serve as novel tools of EHEC O157-mediated host injury and are quite likely involved in the pathogenesis of human diseases.
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Affiliation(s)
| | - Christian Rüter
- Institute of Infectiology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Münster, Germany
| | - Andreas Bauwens
- Institute of Hygiene, University of Münster, Münster, Germany
| | - Lilo Greune
- Institute of Infectiology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Münster, Germany
| | | | - Daniel Steil
- Institute of Hygiene, University of Münster, Münster, Germany
| | - Wenlan Zhang
- Institute of Hygiene, University of Münster, Münster, Germany
| | - Xiaohua He
- Western Regional Research Center, Agricultural Research Service, United States Department of Agriculture (USDA), Albany, California, United States of America
| | - Roland Lloubes
- Laboratoire d'Ingenierie des Systemes Macromoleculaires UMR7255, CNRS-Aix-Marseille Université, Marseille, France
| | - Angelika Fruth
- National Reference Center for Salmonella and Other Enteric Pathogens, Robert Koch Institute, Branch Wernigerode, Wernigerode, Germany
| | - Kwang Sik Kim
- Division of Pediatric Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - M. Alexander Schmidt
- Institute of Infectiology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Münster, Germany
| | - Ulrich Dobrindt
- Institute of Hygiene, University of Münster, Münster, Germany
| | - Alexander Mellmann
- Institute of Hygiene, University of Münster, Münster, Germany
- Interdisciplinary Center for Clinical Research (IZKF), University of Münster, Münster, Germany
| | - Helge Karch
- Institute of Hygiene, University of Münster, Münster, Germany
- Interdisciplinary Center for Clinical Research (IZKF), University of Münster, Münster, Germany
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Scuron MD, Boesze-Battaglia K, Dlakić M, Shenker BJ. The Cytolethal Distending Toxin Contributes to Microbial Virulence and Disease Pathogenesis by Acting As a Tri-Perditious Toxin. Front Cell Infect Microbiol 2016; 6:168. [PMID: 27995094 PMCID: PMC5136569 DOI: 10.3389/fcimb.2016.00168] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 11/15/2016] [Indexed: 12/11/2022] Open
Abstract
This review summarizes the current status and recent advances in our understanding of the role that the cytolethal distending toxin (Cdt) plays as a virulence factor in promoting disease by toxin-producing pathogens. A major focus of this review is on the relationship between structure and function of the individual subunits that comprise the AB2 Cdt holotoxin. In particular, we concentrate on the molecular mechanisms that characterize this toxin and which account for the ability of Cdt to intoxicate multiple cell types by utilizing a ubiquitous binding partner on the cell membrane. Furthermore, we propose a paradigm shift for the molecular mode of action by which the active Cdt subunit, CdtB, is able to block a key signaling cascade and thereby lead to outcomes based upon programming and the role of the phosphatidylinositol 3-kinase (PI-3K) in a variety of cells. Based upon the collective Cdt literature, we now propose that Cdt is a unique and potent virulence factor capable of acting as a tri-perditious toxin that impairs host defenses by: (1) disrupting epithelial barriers; (2) suppressing acquired immunity; (3) promoting pro-inflammatory responses. Thus, Cdt plays a key role in facilitating the early stages of infection and the later stages of disease progression by contributing to persistence and impairing host elimination.
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Affiliation(s)
- Monika D Scuron
- Department of Pathology, School of Dental Medicine, University of Pennsylvania Philadelphia, PA, USA
| | - Kathleen Boesze-Battaglia
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania Philadelphia, PA, USA
| | - Mensur Dlakić
- Department of Microbiology and Immunology, Montana State University Bozeman, MT, USA
| | - Bruce J Shenker
- Department of Pathology, School of Dental Medicine, University of Pennsylvania Philadelphia, PA, USA
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Méndez-Olvera ET, Bustos-Martínez JA, López-Vidal Y, Verdugo-Rodríguez A, Martínez-Gómez D. Cytolethal Distending Toxin From Campylobacter jejuni Requires the Cytoskeleton for Toxic Activity. Jundishapur J Microbiol 2016; 9:e35591. [PMID: 27942359 PMCID: PMC5136451 DOI: 10.5812/jjm.35591] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 09/05/2016] [Accepted: 09/05/2016] [Indexed: 02/07/2023] Open
Abstract
Background Campylobacter jejuni is one of the major causes of infectious diarrhea worldwide. The distending cytolethal toxin (CDT) of Campylobacter spp. interferes with normal cell cycle progression. This toxic effect is considered a result of DNase activity that produces chromosomal DNA damage. To perform this event, the toxin must be endocytosed and translocated to the nucleus. Objectives The aim of this study was to evaluate the role of the cytoskeleton in the translocation of CDT to the nucleus. Methods Campylobacter jejuni ATCC 33291 and seven isolates donated from Instituto de Biotecnologia were used in this study. The presence of CDT genes in C. jejuni strains was determined by PCR. To evaluate the effect of CDT, HeLa cells were treated with bacterial lysate, and the damage and morphological changes were analyzed by microscopy, immunofluorescence staining, and flow cytometry. To evaluate the role of the cytoskeleton, HeLa cells were treated with either latrunculin A or by nocodazole and analyzed by microscopy, flow cytometry, and immunoquantification (ELISA). Results The results obtained showed that the eight strains of C. jejuni, including the reference strain, had the ability to produce the toxin. Usage of latrunculin A and nocodazole, two cytoskeletal inhibitors, blocked the toxic effect in cells treated with the toxin. This phenomenon was evident in flow cytometry analysis and immunoquantification of Cdc2-phosphorylated. Conclusions This work showed that the cytotoxic activity of the C. jejuni CDT is dependent on its endocytosis. The alteration in the microtubules and actin filaments caused a blockage transit of the toxin, preventing it from reaching the nucleus of the cell, as well as preventing DNA fragmentation and alteration of the cell cycle. The CDT toxin appears to be an important element for the pathogenesis of campylobacteriosis, since all clinical isolates showed the presence of cdtA, cdtB and cdtC genes.
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Affiliation(s)
- Estela T. Méndez-Olvera
- Departamento de Producción Agrícola y Animal, and Doctorado en Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana-Xochimilco, México City, México
- Corresponding author: Estela T. Méndez-Olvera, Departamento de Producción Agrícola y Animal, and Doctorado en Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana-Xochimilco, México City, México. E-mail:
| | - Jaime A. Bustos-Martínez
- Departamento de Atención a la Salud, Universidad Autónoma Metropolitana-Xochimilco, México City, México
| | - Yolanda López-Vidal
- Departamento de Microbiología y Parasitología-Facultad de Medicina, Universidad Nacional Autónoma de México, México City, México
| | - Antonio Verdugo-Rodríguez
- Departamento de Microbiología e Inmunología-Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, México City, México
| | - Daniel Martínez-Gómez
- Departamento de Producción Agrícola y Animal, Universidad Autónoma Metropolitana-Xochimilco, México City, México
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Boesze-Battaglia K, Alexander D, Dlakić M, Shenker BJ. A Journey of Cytolethal Distending Toxins through Cell Membranes. Front Cell Infect Microbiol 2016; 6:81. [PMID: 27559534 PMCID: PMC4978709 DOI: 10.3389/fcimb.2016.00081] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 07/26/2016] [Indexed: 02/06/2023] Open
Abstract
The multifunctional role of lipids as structural components of membranes, signaling molecules, and metabolic substrates makes them an ideal partner for pathogens to hijack host cell processes for their own survival. The properties and composition of unique membrane micro-domains such as membrane rafts make these regions a natural target for pathogens as it affords them an opportunity to hijack cell signaling and intracellular trafficking pathways. Cytolethal distending toxins (Cdts), members of the AB2 family of toxins are comprised of three subunits, the active, CdtB unit, and the binding, CdtA-CdtC unit. Cdts are cyclomodulins leading to cell cycle arrest and apoptosis in a wide variety of cell types. Cdts from several species share a requirement for membrane rafts, and often cholesterol specifically for cell binding and CdtB mediated cytotoxicity. In this review we focus on how host–cell membrane bilayer organization contributes to the cell surface association, internalization, and action of bacteria derived cytolethal distending toxins (Cdts), with an emphasis on Aggregatibacter actinomycetemcomitans Cdt.
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Affiliation(s)
| | - Desiree Alexander
- Department of Biochemistry, SDM, University of Pennsylvania Philadelphia, PA, USA
| | - Mensur Dlakić
- Department of Microbiology and Immunology, Montana State University Bozeman, MT, USA
| | - Bruce J Shenker
- Department of Pathology, SDM, University of Pennsylvania Philadelphia, PA, USA
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Taieb F, Petit C, Nougayrède JP, Oswald E. The Enterobacterial Genotoxins: Cytolethal Distending Toxin and Colibactin. EcoSal Plus 2016; 7. [PMID: 27419387 DOI: 10.1128/ecosalplus.esp-0008-2016] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Indexed: 06/06/2023]
Abstract
While the DNA damage induced by ionizing radiation and by many chemical compounds and drugs is well characterized, the genotoxic insults inflicted by bacteria are only scarcely documented. However, accumulating evidence indicates that we are exposed to bacterial genotoxins. The prototypes of such bacterial genotoxins are the Cytolethal Distending Toxins (CDTs) produced by Escherichia coli and Salmonella enterica serovar Typhi. CDTs display the DNase structure fold and activity, and induce DNA strand breaks in the intoxicated host cell nuclei. E. coli and certain other Enterobacteriaceae species synthesize another genotoxin, colibactin. Colibactin is a secondary metabolite, a hybrid polyketide/nonribosomal peptide compound synthesized by a complex biosynthetic machinery. In this review, we summarize the current knowledge on CDT and colibactin produced by E. coli and/or Salmonella Typhi. We describe their prevalence, genetic determinants, modes of action, and impact in infectious diseases or gut colonization, and discuss the possible involvement of these genotoxigenic bacteria in cancer.
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Affiliation(s)
- Frederic Taieb
- Institut de Recherche en Santé Digestive (IRSD), INRA UMR1416, INSERM U1220, Université de Toulouse, CHU Purpan, Toulouse, FRANCE
| | - Claude Petit
- Institut de Recherche en Santé Digestive (IRSD), INRA UMR1416, INSERM U1220, Université de Toulouse, CHU Purpan, Toulouse, FRANCE
| | - Jean-Philippe Nougayrède
- Institut de Recherche en Santé Digestive (IRSD), INRA UMR1416, INSERM U1220, Université de Toulouse, CHU Purpan, Toulouse, FRANCE
| | - Eric Oswald
- Institut de Recherche en Santé Digestive (IRSD), INRA UMR1416, INSERM U1220, Université de Toulouse, CHU Purpan, Toulouse, FRANCE
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Miller R, Wiedmann M. Dynamic Duo-The Salmonella Cytolethal Distending Toxin Combines ADP-Ribosyltransferase and Nuclease Activities in a Novel Form of the Cytolethal Distending Toxin. Toxins (Basel) 2016; 8:E121. [PMID: 27120620 PMCID: PMC4885037 DOI: 10.3390/toxins8050121] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 03/30/2016] [Accepted: 04/15/2016] [Indexed: 01/02/2023] Open
Abstract
The cytolethal distending toxin (CDT) is a well characterized bacterial genotoxin encoded by several Gram-negative bacteria, including Salmonella enterica (S. enterica). The CDT produced by Salmonella (S-CDT) differs from the CDT produced by other bacteria, as it utilizes subunits with homology to the pertussis and subtilase toxins, in place of the traditional CdtA and CdtC subunits. Previously, S-CDT was thought to be a unique virulence factor of S. enterica subspecies enterica serotype Typhi, lending to its classification as the "typhoid toxin." Recently, this important virulence factor has been identified and characterized in multiple nontyphoidal Salmonella (NTS) serotypes as well. The significance of S-CDT in salmonellosis with regards to the: (i) distribution of S-CDT encoding genes among NTS serotypes, (ii) contributions to pathogenicity, (iii) regulation of S-CDT expression, and (iv) the public health implication of S-CDT as it relates to disease severity, are reviewed here.
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Affiliation(s)
- Rachel Miller
- Department of Food Science, Cornell University, Ithaca, NY 14850 USA.
| | - Martin Wiedmann
- Department of Food Science, Cornell University, Ithaca, NY 14850 USA.
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Bacterial genotoxins: The long journey to the nucleus of mammalian cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:567-75. [DOI: 10.1016/j.bbamem.2015.08.016] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 07/17/2015] [Accepted: 08/18/2015] [Indexed: 02/06/2023]
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Lai CK, Chen YA, Lin CJ, Lin HJ, Kao MC, Huang MZ, Lin YH, Chiang-Ni C, Chen CJ, Lo UG, Lin LC, Lin H, Hsieh JT, Lai CH. Molecular Mechanisms and Potential Clinical Applications of Campylobacter jejuni Cytolethal Distending Toxin. Front Cell Infect Microbiol 2016; 6:9. [PMID: 26904508 PMCID: PMC4746238 DOI: 10.3389/fcimb.2016.00009] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 01/18/2016] [Indexed: 12/12/2022] Open
Abstract
Cytolethal distending toxin (CDT), a genotoxin produced by Campylobacter jejuni, is composed of three subunits: CdtA, CdtB, and CdtC. CdtB is a DNase that causes DNA double-strand breaks (DSB) in the nucleus resulting in cell cycle arrest at the G2/M stage and apoptosis. CdtA and CdtC bind to cholesterol-rich microdomains on the cytoplasmic membrane, a process required for the delivery of CdtB to cells. Although a unique motif associated with cholesterol-binding activity has been identified in other pathogens, the mechanism underlying the interaction between the CdtA and CdtC subunits and membrane cholesterol remains unclear. Also, the processes of cell uptake and delivery of CdtB in host cells and the translocation of CdtB into the nucleus are only partially understood. In this review, we focus on the underlying relationship among CDT, membrane cholesterol, and the intracellular trafficking pathway as a unique mechanism for C. jejuni-induced pathogenesis. Moreover, we discuss the clinical aspects of a possible therapeutic application of CDT in cancer therapy. Understanding the molecular mechanism of CDT-host interactions may provide insights into novel strategies to control C. jejuni infection and the development of potential clinical applications of CDT.
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Affiliation(s)
- Cheng-Kuo Lai
- Department of Microbiology and Immunology, Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung UniversityTaoyuan, Taiwan; Department of Urology, University of Texas Southwestern Medical CenterDallas, TX, USA
| | - Yu-An Chen
- School of Medicine, Graduate Institute of Basic Medical Science, China Medical University Taichung, Taiwan
| | - Chun-Jung Lin
- Department of Urology, University of Texas Southwestern Medical CenterDallas, TX, USA; School of Medicine, Graduate Institute of Basic Medical Science, China Medical UniversityTaichung, Taiwan
| | - Hwai-Jeng Lin
- Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical UniversityNew Taipei, Taiwan; Division of Gastroenterology and Hepatology, Department of Internal Medicine, Shuang-Ho HospitalNew Taipei, Taiwan
| | - Min-Chuan Kao
- Department of Microbiology and Immunology, Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University Taoyuan, Taiwan
| | - Mei-Zi Huang
- Department of Microbiology and Immunology, Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung UniversityTaoyuan, Taiwan; School of Medicine, Graduate Institute of Basic Medical Science, China Medical UniversityTaichung, Taiwan
| | - Yu-Hsin Lin
- Department of Urology, University of Texas Southwestern Medical CenterDallas, TX, USA; Department of Biological Science and Technology, China Medical UniversityTaichung, Taiwan
| | - Chuan Chiang-Ni
- Department of Microbiology and Immunology, Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University Taoyuan, Taiwan
| | - Chih-Jung Chen
- Department of Pediatrics, Molecular Infectious Disease Research Center, Chang Gung Children's Hospital and Chang Gung Memorial Hospital Taoyuan, Taiwan
| | - U-Ging Lo
- Department of Urology, University of Texas Southwestern Medical Center Dallas, TX, USA
| | - Li-Chiung Lin
- Department of Urology, University of Texas Southwestern Medical CenterDallas, TX, USA; Department of Life Sciences, National Chung Hsing UniversityTaichung, Taiwan
| | - Ho Lin
- Department of Life Sciences, National Chung Hsing University Taichung, Taiwan
| | - Jer-Tsong Hsieh
- Department of Urology, University of Texas Southwestern Medical CenterDallas, TX, USA; Graduate Institute of Cancer Biology, China Medical UniversityTaichung, Taiwan
| | - Chih-Ho Lai
- Department of Microbiology and Immunology, Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung UniversityTaoyuan, Taiwan; School of Medicine, Graduate Institute of Basic Medical Science, China Medical UniversityTaichung, Taiwan; Department of Pediatrics, Molecular Infectious Disease Research Center, Chang Gung Children's Hospital and Chang Gung Memorial HospitalTaoyuan, Taiwan; Department of Nursing, Asia UniversityTaichung, Taiwan
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Lai CK, Su JC, Lin YH, Chang CS, Feng CL, Lin HJ, Lin CJ, Tseng GC, Liu HH, Hsieh JT, Su HL, Lai CH. Involvement of cholesterol in Campylobacter jejuni cytolethal distending toxin-induced pathogenesis. Future Microbiol 2016; 10:489-501. [PMID: 25865189 DOI: 10.2217/fmb.14.119] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
AIM The aim of this study was to investigate whether cholesterol plays a pivotal role in cytolethal distending toxin (CDT) mediated pathogenic effects in hosts. MATERIALS & METHODS The molecular mechanisms underlying cholesterol sequestering conferred resistance to CDT-induced DNA double-strand breaks (DSBs) and cell cycle arrest were investigated. Histopathological analysis was conducted for evaluating CDT-induced intestinal inflammation in mouse. RESULTS CDT actions were attenuated by treatment of cells with methyl-β-cyclodextrin (MβCD). Severe intestinal inflammation induced by CDT treatment was observed in high-cholesterol diet-fed mice, but not in normal diet-fed mice, indicating that cholesterol is essential for CDT intoxication. CONCLUSION Our findings demonstrate a molecular link between Campylobacter jejuni CDT and cholesterol, which is crucial to facilitate CDT-induced pathogenesis in hosts.
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Affiliation(s)
- Cheng-Kuo Lai
- School of Medicine & Graduate Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan
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Dixon SD, Huynh MM, Tamilselvam B, Spiegelman LM, Son SB, Eshraghi A, Blanke SR, Bradley KA. Distinct Roles for CdtA and CdtC during Intoxication by Cytolethal Distending Toxins. PLoS One 2015; 10:e0143977. [PMID: 26618479 PMCID: PMC4664275 DOI: 10.1371/journal.pone.0143977] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 11/11/2015] [Indexed: 12/29/2022] Open
Abstract
Cytolethal distending toxins (CDTs) are heterotrimeric protein exotoxins produced by a diverse array of Gram-negative pathogens. The enzymatic subunit, CdtB, possesses DNase and phosphatidylinositol 3-4-5 trisphosphate phosphatase activities that induce host cell cycle arrest, cellular distension and apoptosis. To exert cyclomodulatory and cytotoxic effects CDTs must be taken up from the host cell surface and transported intracellularly in a manner that ultimately results in localization of CdtB to the nucleus. However, the molecular details and mechanism by which CDTs bind to host cells and exploit existing uptake and transport pathways to gain access to the nucleus are poorly understood. Here, we report that CdtA and CdtC subunits of CDTs derived from Haemophilus ducreyi (Hd-CDT) and enteropathogenic E. coli (Ec-CDT) are independently sufficient to support intoxication by their respective CdtB subunits. CdtA supported CdtB-mediated killing of T-cells and epithelial cells that was nearly as efficient as that observed with holotoxin. In contrast, the efficiency by which CdtC supported intoxication was dependent on the source of the toxin as well as the target cell type. Further, CdtC was found to alter the subcellular trafficking of Ec-CDT as determined by sensitivity to EGA, an inhibitor of endosomal trafficking, colocalization with markers of early and late endosomes, and the kinetics of DNA damage response. Finally, host cellular cholesterol was found to influence sensitivity to intoxication mediated by Ec-CdtA, revealing a role for cholesterol or cholesterol-rich membrane domains in intoxication mediated by this subunit. In summary, data presented here support a model in which CdtA and CdtC each bind distinct receptors on host cell surfaces that direct alternate intracellular uptake and/or trafficking pathways.
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Affiliation(s)
- Shandee D. Dixon
- Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, California, United States of America
| | - Melanie M. Huynh
- Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, California, United States of America
| | - Batcha Tamilselvam
- Department of Microbiology, Institute for Genomic Biology, University of Illinois Urbana, Urbana, Illinois, United States of America
| | - Lindsey M. Spiegelman
- Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, California, United States of America
| | - Sophia B. Son
- Department of Microbiology, Institute for Genomic Biology, University of Illinois Urbana, Urbana, Illinois, United States of America
| | - Aria Eshraghi
- Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, California, United States of America
| | - Steven R. Blanke
- Department of Microbiology, Institute for Genomic Biology, University of Illinois Urbana, Urbana, Illinois, United States of America
| | - Kenneth A. Bradley
- Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, California, United States of America
- California NanoSystems Institute, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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Rosadi F, Fiorentini C, Fabbri A. Bacterial protein toxins in human cancers. Pathog Dis 2015; 74:ftv105. [DOI: 10.1093/femspd/ftv105] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/29/2015] [Indexed: 12/16/2022] Open
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Bacterial Genotoxins: Merging the DNA Damage Response into Infection Biology. Biomolecules 2015; 5:1762-82. [PMID: 26270677 PMCID: PMC4598774 DOI: 10.3390/biom5031762] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 08/05/2015] [Accepted: 08/06/2015] [Indexed: 02/07/2023] Open
Abstract
Bacterial genotoxins are unique among bacterial toxins as their molecular target is DNA. The consequence of intoxication or infection is induction of DNA breaks that, if not properly repaired, results in irreversible cell cycle arrest (senescence) or death of the target cells. At present, only three bacterial genotoxins have been identified. Two are protein toxins: the cytolethal distending toxin (CDT) family produced by a number of Gram-negative bacteria and the typhoid toxin produced by Salmonella enterica serovar Typhi. The third member, colibactin, is a peptide-polyketide genotoxin, produced by strains belonging to the phylogenetic group B2 of Escherichia coli. This review will present the cellular effects of acute and chronic intoxication or infection with the genotoxins-producing bacteria. The carcinogenic properties and the role of these effectors in the context of the host-microbe interaction will be discussed. We will further highlight the open questions that remain to be solved regarding the biology of this unusual family of bacterial toxins.
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The Aggregatibacter actinomycetemcomitans Cytolethal Distending Toxin Active Subunit CdtB Contains a Cholesterol Recognition Sequence Required for Toxin Binding and Subunit Internalization. Infect Immun 2015. [PMID: 26216427 DOI: 10.1128/iai.00788-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Induction of cell cycle arrest in lymphocytes following exposure to the Aggregatibacter actinomycetemcomitans cytolethal distending toxin (Cdt) is dependent upon the integrity of lipid membrane microdomains. Moreover, we have previously demonstrated that the association of Cdt with target cells involves the CdtC subunit which binds to cholesterol via a cholesterol recognition amino acid consensus sequence (CRAC site). In this study, we demonstrate that the active Cdt subunit, CdtB, also is capable of binding to large unilamellar vesicles (LUVs) containing cholesterol. Furthermore, CdtB binding to cholesterol involves a similar CRAC site as that demonstrated for CdtC. Mutation of the CRAC site reduces binding to model membranes as well as toxin binding and CdtB internalization in both Jurkat cells and human macrophages. A concomitant reduction in Cdt-induced toxicity was also noted, indicated by reduced cell cycle arrest and apoptosis in Jurkat cells and a reduction in the proinflammatory response in macrophages (interleukin 1β [IL-1β] and tumor necrosis factor alpha [TNF-α] release). Collectively, these observations indicate that membrane cholesterol serves as an essential ligand for both CdtC and CdtB and, further, that this binding is necessary for both internalization of CdtB and subsequent molecular events leading to intoxication of cells.
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DiRienzo JM. Uptake and processing of the cytolethal distending toxin by mammalian cells. Toxins (Basel) 2014; 6:3098-116. [PMID: 25365527 PMCID: PMC4247254 DOI: 10.3390/toxins6113098] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 10/10/2014] [Accepted: 10/10/2014] [Indexed: 11/16/2022] Open
Abstract
The cytolethal distending toxin (Cdt) is a heterotrimeric holotoxin produced by a diverse group of Gram-negative pathogenic bacteria. The Cdts expressed by the members of this group comprise a subclass of the AB toxin superfamily. Some AB toxins have hijacked the retrograde transport pathway, carried out by the Golgi apparatus and endoplasmic reticulum (ER), to translocate to cytosolic targets. Those toxins have been used as tools to decipher the roles of the Golgi and ER in intracellular transport and to develop medically useful delivery reagents. In comparison to the other AB toxins, the Cdt exhibits unique properties, such as translocation to the nucleus, that present specific challenges in understanding the precise molecular details of the trafficking pathway in mammalian cells. The purpose of this review is to present current information about the mechanisms of uptake and translocation of the Cdt in relation to standard concepts of endocytosis and retrograde transport. Studies of the Cdt intoxication process to date have led to the discovery of new translocation pathways and components and most likely will continue to reveal unknown features about the mechanisms by which bacterial proteins target the mammalian cell nucleus. Insight gained from these studies has the potential to contribute to the development of novel therapeutic strategies.
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Affiliation(s)
- Joseph M DiRienzo
- Department of Microbiology, School of Dental Medicine, University of Pennsylvania, 240 South 40th Street, Philadelphia, PA 19104, USA.
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Abstract
Some of the most potent toxins produced by plants and bacteria are members of a large family known as the AB toxins. AB toxins are generally characterized by a heterogenous complex consisting of two protein chains arranged in various monomeric or polymeric configurations. The newest class within this superfamily is the cytolethal distending toxin (Cdt). The Cdt is represented by a subfamily of toxins produced by a group of taxonomically distinct Gram negative bacteria. Members of this subfamily have a related AB-type chain or subunit configuration and properties distinctive to the AB paradigm. In this review, the unique structural and cytotoxic properties of the Cdt subfamily, target cell specificities, intoxication pathway, modes of action, and relationship to the AB toxin superfamily are compared and contrasted.
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Eshraghi A, Dixon SD, Tamilselvam B, Kim EJK, Gargi A, Kulik JC, Damoiseaux R, Blanke SR, Bradley KA. Cytolethal distending toxins require components of the ER-associated degradation pathway for host cell entry. PLoS Pathog 2014; 10:e1004295. [PMID: 25078082 PMCID: PMC4117610 DOI: 10.1371/journal.ppat.1004295] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 06/23/2014] [Indexed: 11/18/2022] Open
Abstract
Intracellular acting protein exotoxins produced by bacteria and plants are important molecular determinants that drive numerous human diseases. A subset of these toxins, the cytolethal distending toxins (CDTs), are encoded by several Gram-negative pathogens and have been proposed to enhance virulence by allowing evasion of the immune system. CDTs are trafficked in a retrograde manner from the cell surface through the Golgi apparatus and into the endoplasmic reticulum (ER) before ultimately reaching the host cell nucleus. However, the mechanism by which CDTs exit the ER is not known. Here we show that three central components of the host ER associated degradation (ERAD) machinery, Derlin-2 (Derl2), the E3 ubiquitin-protein ligase Hrd1, and the AAA ATPase p97, are required for intoxication by some CDTs. Complementation of Derl2-deficient cells with Derl2:Derl1 chimeras identified two previously uncharacterized functional domains in Derl2, the N-terminal 88 amino acids and the second ER-luminal loop, as required for intoxication by the CDT encoded by Haemophilus ducreyi (Hd-CDT). In contrast, two motifs required for Derlin-dependent retrotranslocation of ERAD substrates, a conserved WR motif and an SHP box that mediates interaction with the AAA ATPase p97, were found to be dispensable for Hd-CDT intoxication. Interestingly, this previously undescribed mechanism is shared with the plant toxin ricin. These data reveal a requirement for multiple components of the ERAD pathway for CDT intoxication and provide insight into a Derl2-dependent pathway exploited by retrograde trafficking toxins.
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Affiliation(s)
- Aria Eshraghi
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Shandee D. Dixon
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Batcha Tamilselvam
- Department of Microbiology, Institute for Genomic Biology, University of Illinois, Urbana, Urbana, Illinois, United States of America
| | - Emily Jin-Kyung Kim
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Amandeep Gargi
- Department of Microbiology, Institute for Genomic Biology, University of Illinois, Urbana, Urbana, Illinois, United States of America
| | - Julia C. Kulik
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Robert Damoiseaux
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Steven R. Blanke
- Department of Microbiology, Institute for Genomic Biology, University of Illinois, Urbana, Urbana, Illinois, United States of America
| | - Kenneth A. Bradley
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, United States of America
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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Bezine E, Vignard J, Mirey G. The cytolethal distending toxin effects on Mammalian cells: a DNA damage perspective. Cells 2014; 3:592-615. [PMID: 24921185 PMCID: PMC4092857 DOI: 10.3390/cells3020592] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 05/28/2014] [Accepted: 05/28/2014] [Indexed: 12/27/2022] Open
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.
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Affiliation(s)
- Elisabeth Bezine
- INRA, UMR1331, Toxalim, Research Centre in Food Toxicology, F-31027 Toulouse, France.
| | - Julien Vignard
- INRA, UMR1331, Toxalim, Research Centre in Food Toxicology, F-31027 Toulouse, France.
| | - Gladys Mirey
- INRA, UMR1331, Toxalim, Research Centre in Food Toxicology, F-31027 Toulouse, France.
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Cytolethal distending toxin (CDT) is a radiomimetic agent and induces persistent levels of DNA double-strand breaks in human fibroblasts. DNA Repair (Amst) 2014; 18:31-43. [PMID: 24680221 DOI: 10.1016/j.dnarep.2014.03.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 02/07/2014] [Accepted: 03/03/2014] [Indexed: 11/22/2022]
Abstract
Cytolethal distending toxin (CDT) is a unique genotoxin produced by several pathogenic bacteria. The tripartite protein toxin is internalized into mammalian cells via endocytosis followed by retrograde transport to the ER. Upon translocation into the nucleus, CDT catalyzes the formation of DNA double-strand breaks (DSBs) due to its intrinsic endonuclease activity. In the present study, we compared the DNA damage response (DDR) in human fibroblasts triggered by recombinant CDT to that of ionizing radiation (IR), a well-known DSB inducer. Furthermore, we dissected the pathways involved in the detection and repair of CDT-induced DNA lesions. qRT-PCR array-based mRNA and western blot analyses showed a partial overlap in the DDR pattern elicited by CDT and IR, with strong activation of both the ATM-Chk2 and the ATR-Chk1 axis. In line with its in vitro DNase I-like activity on plasmid DNA, neutral and alkaline Comet assay revealed predominant induction of DSBs in CDT-treated fibroblasts, whereas irradiation of cells generated higher amounts of SSBs and alkali-labile sites. Using confocal microscopy, the dynamics of the DSB surrogate marker γ-H2AX was monitored after pulse treatment with CDT or IR. In contrast to the fast induction and disappearance of γ-H2AX-foci observed in irradiated cells, the number of γ-H2AX-foci induced by CDT were formed with a delay and persisted. 53BP1 foci were also generated following CDT treatment and co-localized with γ-H2AX foci. We further demonstrated that ATM-deficient cells are very sensitive to CDT-induced DNA damage as reflected by increased cell death rates with concomitant cleavage of caspase-3 and PARP-1. Finally, we provided novel evidence that both homologous recombination (HR) and non-homologous end joining (NHEJ) protect against CDT-elicited DSBs. In conclusion, the findings suggest that CDT functions as a radiomimetic agent and, therefore, is an attractive tool for selectively inducing persistent levels of DSBs and unveiling the associated cellular responses.
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Varon C, Mocan I, Mihi B, Péré-Védrenne C, Aboubacar A, Moraté C, Oleastro M, Doignon F, Laharie D, Mégraud F, Ménard A. Helicobacter pullorum Cytolethal Distending Toxin Targets Vinculin and Cortactin and Triggers Formation of Lamellipodia in Intestinal Epithelial Cells. J Infect Dis 2014; 209:588-99. [DOI: 10.1093/infdis/jit539] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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Teter K. Toxin instability and its role in toxin translocation from the endoplasmic reticulum to the cytosol. Biomolecules 2013; 3:997-1029. [PMID: 24970201 PMCID: PMC4030972 DOI: 10.3390/biom3040997] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 11/26/2013] [Accepted: 11/27/2013] [Indexed: 12/21/2022] Open
Abstract
AB toxins enter a host cell by receptor-mediated endocytosis. The catalytic A chain then crosses the endosome or endoplasmic reticulum (ER) membrane to reach its cytosolic target. Dissociation of the A chain from the cell-binding B chain occurs before or during translocation to the cytosol, and only the A chain enters the cytosol. In some cases, AB subunit dissociation is facilitated by the unique physiology and function of the ER. The A chains of these ER-translocating toxins are stable within the architecture of the AB holotoxin, but toxin disassembly results in spontaneous or assisted unfolding of the isolated A chain. This unfolding event places the A chain in a translocation-competent conformation that promotes its export to the cytosol through the quality control mechanism of ER-associated degradation. A lack of lysine residues for ubiquitin conjugation protects the exported A chain from degradation by the ubiquitin-proteasome system, and an interaction with host factors allows the cytosolic toxin to regain a folded, active state. The intrinsic instability of the toxin A chain thus influences multiple steps of the intoxication process. This review will focus on the host-toxin interactions involved with A chain unfolding in the ER and A chain refolding in the cytosol.
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Affiliation(s)
- Ken Teter
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, 12722 Research Parkway, Orlando, FL 32826, USA.
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Guidi R, Levi L, Rouf SF, Puiac S, Rhen M, Frisan T. Salmonella enterica delivers its genotoxin through outer membrane vesicles secreted from infected cells. Cell Microbiol 2013; 15:2034-50. [PMID: 23869968 DOI: 10.1111/cmi.12172] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 06/19/2013] [Accepted: 07/10/2013] [Indexed: 02/06/2023]
Abstract
Cytolethal-distending toxins (CDTs) belong to a family of DNA damage inducing exotoxins that are produced by several Gram-negative bacteria. Salmonella enterica serovar Typhi expresses its CDT (named as Typhoid toxin) only in the Salmonella-containing vacuole (SCV) of infected cells, which requires its export for cell intoxication. The mechanisms of secretion, release in the extracellular space and uptake by bystander cells are poorly understood. We have addressed these issues using a recombinant S. Typhimurium strain, MC71-CDT, where the genes encoding for the PltA, PltB and CdtB subunits of the Typhoid toxin are expressed under control of the endogenous promoters. MC71-CDT grown under conditions that mimic the SCV secreted the holotoxin in outer membrane vesicles (OMVs). Epithelial cells infected with MC71-CDT also secreted OMVs-like vesicles. The release of these extracellular vesicles required an intact SCV and relied on anterograde transport towards the cellular cortex on microtubule and actin tracks. Paracrine internalization of Typhoid toxin-loaded OMVs by bystander cells was dependent on dynamin-1, indicating active endocytosis. The subsequent induction of DNA damage required retrograde transport of the toxin through the Golgi complex. These data provide new insights on the mode of secretion of exotoxins by cells infected with intracellular bacteria.
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Affiliation(s)
- Riccardo Guidi
- Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
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