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Gu J, Lin Y, Wang Z, Pan Q, Cai G, He Q, Xu X, Cai X. Campylobacter jejuni Cytolethal Distending Toxin Induces GSDME-Dependent Pyroptosis in Colonic Epithelial Cells. Front Cell Infect Microbiol 2022; 12:853204. [PMID: 35573789 PMCID: PMC9093597 DOI: 10.3389/fcimb.2022.853204] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 03/30/2022] [Indexed: 01/02/2023] Open
Abstract
Background Cytolethal distending toxin (CDT) is a critical virulence factor of Campylobacter jejuni, and it induces cell death and regulates inflammation response in human epithelial cells. Pyroptosis is an inflammatory form of programmed cell death (PCD), but whether it is involved in CDT-mediated cytotoxicity remains elusive. Aims This study explores the role and mechanism of pyroptosis in CDT-mediated cytotoxicity. Methods HCT116 and FHC cell lines were treated with CDT. Cell Counting Kit-8 (CCK-8) assay was used to detect cell viability. Western blotting was used to measure the expression of related proteins in the pathway, and cell morphology observation, annexin V/propidium iodide (PI) staining and lactate dehydrogenase (LDH) release assay were performed to evaluate the occurrence of pyroptosis. Result Our results show that C. jejuni CDT effectively induces pyroptosis in a dose- and time- dependent manner in human colonic epithelial cells owing to its DNase activity. Specific pyroptotic features including large bubbles emerging from plasma membrane and LDH release were observed upon CDT treatment. Moreover, CDT-induced pyroptosis involves the caspase-9/caspase-3 axis, which is followed by gasdermin E (GSDME) cleavage rather than gasdermin D (GSDMD). N-acetyl cysteine (NAC), a reactive oxygen species (ROS) inhibitor, attenuates the activation of caspase-9/3, the cleavage of GSDME and pyroptotic characteristic, therefore demonstrating ROS initiates pyroptotic signaling. Conclusions We first clarify a molecular mechanism that CDT induces pyroptosis via ROS/caspase-9/caspase-3/GSDME signaling. These findings provide a new insight on understanding of CDT-induced pathogenesis at the molecular level.
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Affiliation(s)
- Jiayun Gu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Yan Lin
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Zhichao Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Qicong Pan
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Guohua Cai
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Qigai He
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Xiaojuan Xu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Xuwang Cai
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
- *Correspondence: Xuwang Cai,
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Qian M, Cao S, Wang T, Xu X, Zhang Q. Apoptosis triggered by cytolethal distending toxin B subunit of Helicobacter hepaticus is aggravated by autophagy inhibition in mouse hepatocytes. Biochem Biophys Res Commun 2022; 598:40-46. [PMID: 35151202 DOI: 10.1016/j.bbrc.2022.01.121] [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: 12/03/2021] [Accepted: 01/29/2022] [Indexed: 11/02/2022]
Abstract
Hepatocytes injury caused by cytolethal distending toxin (CDT) are major events during helicobacter hepaticus (H.hepaticus) infection. Recent study showed that pre-survival autophagy was promoted against CdtB subunit induced DNA damage. In the present study, we demonstrated that inflammatory cytokines IL-6, IL-1β, TNF-α, IFN-α, IFN-γ expression and STAT phosphorylation were promoted by CdtB. Besides, CdtB decreased cell viability while promote apoptosis in mouse liver (AML12) cells. Especially, apoptotic protein caspase-9, caspase-3 and PARP were activated while the ratio of Bcl-2/Bax was decreased after CdtB treatment. Moreover, apoptosis induced by CdtB was inhibited due to Erk/p38 MAPK signaling pathway suppression performed with SB203580 or U0126. Meanwhile, we found that CdtB increased autophagic marker levels accompanied by Akt/mTOR/P70S6K signaling pathway in a dose dependent manner. To assess the correlation between autophagy and apoptosis induced by H.hepaticus, chloroquine (CQ, 50 μM) was employed to inhibit autophagy. The result showed that inhibition of autophagy with CQ treatment promoted apoptosis induced by CdtB. Altogether, all these results suggest that CdtB triggers apoptosis via MAPK/Erk/p38 signaling pathway in caspase dependent manner, which was prevented by autophagy in AML12 cells. Collectively, our findings provide new insights into the virulence potential of CdtB on the molecular pathogenesis throughout H.hepaticus infection.
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Affiliation(s)
- Miao Qian
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Shuyang Cao
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Tao Wang
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Xiangming Xu
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, China; Taizhou University, Taizhou, China.
| | - Quan Zhang
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, China; Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, China.
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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: 4] [Impact Index Per Article: 1.3] [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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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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The Cell-Cycle Regulatory Protein p21 CIP1/WAF1 Is Required for Cytolethal Distending Toxin (Cdt)-Induced Apoptosis. Pathogens 2020; 9:pathogens9010038. [PMID: 31906446 PMCID: PMC7168616 DOI: 10.3390/pathogens9010038] [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: 11/14/2019] [Revised: 12/22/2019] [Accepted: 12/28/2019] [Indexed: 12/27/2022] Open
Abstract
The Aggregatibacter actinomycetemcomitans cytolethal distending toxin (Cdt) induces lymphocytes to undergo cell-cycle arrest and apoptosis; toxicity is dependent upon the active Cdt subunit, CdtB. We now demonstrate that p21CIP1/WAF1 is critical to Cdt-induced apoptosis. Cdt induces increases in the levels of p21CIP1/WAF1 in lymphoid cell lines, Jurkat and MyLa, and in primary human lymphocytes. These increases were dependent upon CdtB’s ability to function as a phosphatidylinositol (PI) 3,4,5-triphosphate (PIP3) phosphatase. It is noteworthy that Cdt-induced increases in the levels of p21CIP1/WAF1 were accompanied by a significant decline in the levels of phosphorylated p21CIP1/WAF1. The significance of Cdt-induced p21CIP1/WAF1 increase was assessed by preventing these changes with a two-pronged approach; pre-incubation with the novel p21CIP1/WAF1 inhibitor, UC2288, and development of a p21CIP1/WAF1-deficient cell line (Jurkatp21−) using clustered regularly interspaced short palindromic repeats (CRISPR)/cas9 gene editing. UC2288 blocked toxin-induced increases in p21CIP1/WAF1, and JurkatWT cells treated with this inhibitor exhibited reduced susceptibility to Cdt-induced apoptosis. Likewise, Jurkatp21− cells failed to undergo toxin-induced apoptosis. The linkage between Cdt, p21CIP1/WAF1, and apoptosis was further established by demonstrating that Cdt-induced increases in levels of the pro-apoptotic proteins Bid, Bax, and Bak were dependent upon p21CIP1/WAF1 as these changes were not observed in Jurkatp21− cells. Finally, we determined that the p21CIP1/WAF1 increases were dependent upon toxin-induced increases in the level and activity of the chaperone heat shock protein (HSP) 90. We propose that p21CIP1/WAF1 plays a key pro-apoptotic role in mediating Cdt-induced toxicity.
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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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Huang C, Wen C, Yang M, Gan D, Fan C, Li A, Li Q, Zhao J, Zhu L, Lu D. Lycopene protects against t-BHP-induced neuronal oxidative damage and apoptosis via activation of the PI3K/Akt pathway. Mol Biol Rep 2019; 46:3387-3397. [PMID: 31006097 DOI: 10.1007/s11033-019-04801-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 04/05/2019] [Indexed: 12/18/2022]
Abstract
Oxidative stress is a key factor of and closely implicated in the pathogenesis of Alzheimer's disease (AD). We herein used tert-butyl hydroperoxide (t-BHP) to induce oxidative stress and mimic oxidative neurotoxicity in vitro. Lycopene is a natural antioxidant that has a strong ability to eliminate free radicals and shows effective protection in some neurodegenerative disease models. However, the effect of lycopene on t-BHP-induced neuronal damage in primary mouse neurons is unknown. This study aimed to investigate the effects of lycopene on t-BHP-induced neuronal damage and the related mechanisms. We found that lycopene pretreatment effectively enhanced the cell viability, improved the neuron morphology, increased the GSH/GSSG level, restored the mitochondrial membrane potential (ΔΨm) and decreased reactive oxygen species generation. Furthermore, lycopene reduced the ratios of Bax:Bcl-2 and cleaved caspase-3:caspase-3 and the level of cytochrome C, increased the levels of synaptophysin (SYP) and postsynaptic density 95 (PSD95) and activated the PI3K/Akt pathway. In conclusion, lycopene attenuated oxidative stress and reduced t-BHP-induced cell apoptosis, and the mechanism is likely related to activation of the PI3K/Akt pathway. Therefore, lycopene is a potential agent for preventing oxidative stress-mediated AD.
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Affiliation(s)
- Cuiqin Huang
- Department of Pathophysiology, Institute of Brain Science Research, Key Laboratory of State Administration of Traditional Chinese Medicine of the People's Republic of China, School of Medicine, Jinan University, Guangzhou, 510632, Guangdong, China
| | - Caiyan Wen
- Department of Pathophysiology, Institute of Brain Science Research, Key Laboratory of State Administration of Traditional Chinese Medicine of the People's Republic of China, School of Medicine, Jinan University, Guangzhou, 510632, Guangdong, China
| | - Mei Yang
- Department of Pathophysiology, Institute of Brain Science Research, Key Laboratory of State Administration of Traditional Chinese Medicine of the People's Republic of China, School of Medicine, Jinan University, Guangzhou, 510632, Guangdong, China
| | - Danhui Gan
- Department of Pathophysiology, Institute of Brain Science Research, Key Laboratory of State Administration of Traditional Chinese Medicine of the People's Republic of China, School of Medicine, Jinan University, Guangzhou, 510632, Guangdong, China
- Department of Pathology, Guangzhou Overseas Chinese Hospital, The First Affiliated Hospital of Jinan University, Guangzhou, 510630, Guangdong, China
| | - Chongzhu Fan
- Department of Pathophysiology, Institute of Brain Science Research, Key Laboratory of State Administration of Traditional Chinese Medicine of the People's Republic of China, School of Medicine, Jinan University, Guangzhou, 510632, Guangdong, China
| | - An Li
- Department of Pathophysiology, Institute of Brain Science Research, Key Laboratory of State Administration of Traditional Chinese Medicine of the People's Republic of China, School of Medicine, Jinan University, Guangzhou, 510632, Guangdong, China
| | - Qin Li
- Department of Pathophysiology, Institute of Brain Science Research, Key Laboratory of State Administration of Traditional Chinese Medicine of the People's Republic of China, School of Medicine, Jinan University, Guangzhou, 510632, Guangdong, China
| | - Jiayi Zhao
- Department of Pathophysiology, Institute of Brain Science Research, Key Laboratory of State Administration of Traditional Chinese Medicine of the People's Republic of China, School of Medicine, Jinan University, Guangzhou, 510632, Guangdong, China
| | - Lihong Zhu
- Department of Pathophysiology, Institute of Brain Science Research, Key Laboratory of State Administration of Traditional Chinese Medicine of the People's Republic of China, School of Medicine, Jinan University, Guangzhou, 510632, Guangdong, China
| | - Daxiang Lu
- Department of Pathophysiology, Institute of Brain Science Research, Key Laboratory of State Administration of Traditional Chinese Medicine of the People's Republic of China, School of Medicine, Jinan University, Guangzhou, 510632, Guangdong, China.
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Ganji L, Alebouyeh M, Shirazi MH, Zali MR. Comparative transcriptional analysis for Toll-like receptors, inflammatory cytokines, and apoptotic genes in response to different cytolethal-encoding and noncoding isolates of Salmonella enterica and Campylobacter jejuni from food and human stool. Microb Pathog 2019; 133:103550. [PMID: 31112773 DOI: 10.1016/j.micpath.2019.103550] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 05/16/2019] [Accepted: 05/17/2019] [Indexed: 12/24/2022]
Abstract
Diversity of Campylobacter and Salmonella strains in interaction with epithelial cells may explain distinct modes of the pathogenesis, varying from mild watery to severe inflammatory diarrhea. We analyzed impact of this diversity, in relation to carriage and expression of cytholethal distending toxin B (cdtB), on alteration of IL-8, TNF-α, TLR2, TLR4, TLR5, CASP3 mRNA and cytokine levels in HT-29 cell line. A diversity was observed for induction of genes among different strains. Great diversity in IL-8 induction was detected between cdtB+ and cdtB- strains. Early analysis showed down-regulation of TNF-α, mostly among cdtB+ strains. Any increase or decrease in expression of TLR2 in the cdtB-C. jejuni strains was orderly correlated with increase or decrease of TLR4 and TNF-α. Up-regulation of CASP3 was followed by upregulation of TLR2, -4 and/or TNF-α, regardless to the cdtB status. In conclusion, induction of inflammatory response could mediate by distinct C. jejuni and S. enterica strains by several ways.
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Affiliation(s)
- Leila Ganji
- Department of Pathobiology, School of Public Health, University of Medical Sciences, Tehran, Iran; Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Research Center of Health Reference Laboratory, Ministry of Health and Medical Education, Tehran, Iran
| | - Masoud Alebouyeh
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Pediatric Infections Research Center, Research Institute for Children's Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Mohammad Hassan Shirazi
- Department of Pathobiology, School of Public Health, University of Medical Sciences, Tehran, Iran
| | - Mohammad Reza Zali
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Science, Tehran, Iran
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9
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The Typhoid Toxin Produced by the Nontyphoidal Salmonella enterica Serotype Javiana Is Required for Induction of a DNA Damage Response In Vitro and Systemic Spread In Vivo. mBio 2018; 9:mBio.00467-18. [PMID: 29588404 PMCID: PMC5874915 DOI: 10.1128/mbio.00467-18] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The Salmonella cytolethal distending toxin (S-CDT), first described as the “typhoid toxin” in Salmonella enterica subsp. enterica serotype Typhi, induces DNA damage in eukaryotic cells. Recent studies have shown that more than 40 nontyphoidal Salmonella (NTS) serotypes carry genes that encode S-CDT, yet very little is known about the activity, function, and role of S-CDT in NTS. Here we show that deletion of genes encoding the binding subunit (pltB) and a bacteriophage muramidase predicted to play a role in toxin export (ttsA) does not abolish toxin activity in the S-CDT-positive NTS Salmonella enterica subsp. enterica serotype Javiana. However, S. Javiana strains harboring deletions of both pltB and its homolog artB, had a complete loss of S-CDT activity, suggesting that S. Javiana carries genes encoding two variants of the binding subunit. S-CDT-mediated DNA damage, as determined by phosphorylation of histone 2AX (H2AX), producing phosphorylated H2AX (γH2AX), was restricted to epithelial cells in S and G2/M phases of the cell cycle and did not result in apoptosis or cell death. Compared to mice infected with a ΔcdtB strain, mice infected with wild-type S. Javiana had significantly higher levels of S. Javiana in the liver, but not in the spleen, ileum, or cecum. Overall, we show that production of active S-CDT by NTS serotype S. Javiana requires different genes (cdtB, pltA, and either pltB or artB) for expression of biologically active toxin than those reported for S-CDT production by S. Typhi (cdtB, pltA, pltB, and ttsA). However, as in S. Typhi, NTS S-CDT influences the outcome of infection both in vitro and in vivo. Nontyphoidal Salmonella (NTS) are a major cause of bacterial food-borne illness worldwide; however, our understanding of virulence mechanisms that determine the outcome and severity of nontyphoidal salmonellosis is incompletely understood. Here we show that S-CDT produced by NTS plays a significant role in the outcome of infection both in vitro and in vivo, highlighting S-CDT as an important virulence factor for nontyphoidal Salmonella serotypes. Our data also contribute novel information about the function of S-CDT, as S-CDT-mediated DNA damage occurs only during certain phases of the cell cycle, and the resulting damage does not induce cell death as assessed using a propidium iodide exclusion assay. Importantly, our data support that, despite having genetically similar S-CDT operons, NTS serotype S. Javiana has different genetic requirements than S. Typhi, for the production and export of active S-CDT.
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Péré-Védrenne C, Prochazkova-Carlotti M, Rousseau B, He W, Chambonnier L, Sifré E, Buissonnière A, Dubus P, Mégraud F, Varon C, Ménard A. The Cytolethal Distending Toxin Subunit CdtB of Helicobacter hepaticus Promotes Senescence and Endoreplication in Xenograft Mouse Models of Hepatic and Intestinal Cell Lines. Front Cell Infect Microbiol 2017; 7:268. [PMID: 28713773 PMCID: PMC5491915 DOI: 10.3389/fcimb.2017.00268] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 06/06/2017] [Indexed: 12/15/2022] Open
Abstract
Cytolethal distending toxins (CDTs) are common among pathogenic bacteria of the human and animal microbiota. CDTs exert cytopathic effets, via their active CdtB subunit. No clear description of those cytopathic effects has been reported at the cellular level in the target organs in vivo. In the present study, xenograft mouse models of colon and liver cell lines were set up to study the effects of the CdtB subunit of Helicobacter hepaticus. Conditional transgenic cell lines were established, validated in vitro and then engrafted into immunodeficient mice. After successful engraftment, mice were treated with doxycyclin to induce the expression of transgenes (red fluorescent protein, CdtB, and mutated CdtB). For both engrafted cell lines, results revealed a delayed tumor growth and a reduced tumor weight in CdtB-expressing tumors compared to controls. CdtB-derived tumors showed γ-H2AX foci formation, an increase in apoptosis, senescence, p21 and Ki-67 nuclear antigen expression. No difference in proliferating cells undergoing mitosis (phospho-histone H3) was observed. CdtB intoxication was also associated with an overexpression of cytokeratins in cells at the invasive front of the tumor as well as an increase in ploidy. All these features are hallmarks of endoreplication, as well as aggressiveness in cancer. These effects were dependent on the histidine residue at position 265 of the CdtB, underlying the importance of this residue in CdtB catalytic activity. Taken together, these data indicate that the CdtB triggers senescence and cell endoreplication leading to giant polyploid cells in these xenograft mouse models.
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Affiliation(s)
- Christelle Péré-Védrenne
- Institut National de la Santé et de la Recherche Médicale, UMR1053 Bordeaux Research in Translational Oncology, BaRITOnBordeaux, France
- UMR1053 Bordeaux Research in Translational Oncology, BaRITOn, Université de BordeauxBordeaux, France
| | - Martina Prochazkova-Carlotti
- Institut National de la Santé et de la Recherche Médicale, UMR1053 Bordeaux Research in Translational Oncology, BaRITOnBordeaux, France
- UMR1053 Bordeaux Research in Translational Oncology, BaRITOn, Université de BordeauxBordeaux, France
| | - Benoit Rousseau
- Service Commun des Animaleries, Université de BordeauxBordeaux, France
| | - Wencan He
- Institut National de la Santé et de la Recherche Médicale, UMR1053 Bordeaux Research in Translational Oncology, BaRITOnBordeaux, France
- UMR1053 Bordeaux Research in Translational Oncology, BaRITOn, Université de BordeauxBordeaux, France
| | - Lucie Chambonnier
- Institut National de la Santé et de la Recherche Médicale, UMR1053 Bordeaux Research in Translational Oncology, BaRITOnBordeaux, France
- UMR1053 Bordeaux Research in Translational Oncology, BaRITOn, Université de BordeauxBordeaux, France
| | - Elodie Sifré
- Institut National de la Santé et de la Recherche Médicale, UMR1053 Bordeaux Research in Translational Oncology, BaRITOnBordeaux, France
- UMR1053 Bordeaux Research in Translational Oncology, BaRITOn, Université de BordeauxBordeaux, France
| | - Alice Buissonnière
- Institut National de la Santé et de la Recherche Médicale, UMR1053 Bordeaux Research in Translational Oncology, BaRITOnBordeaux, France
- UMR1053 Bordeaux Research in Translational Oncology, BaRITOn, Université de BordeauxBordeaux, France
| | - Pierre Dubus
- Institut National de la Santé et de la Recherche Médicale, UMR1053 Bordeaux Research in Translational Oncology, BaRITOnBordeaux, France
- UMR1053 Bordeaux Research in Translational Oncology, BaRITOn, Université de BordeauxBordeaux, France
- CHU Hôpitaux de Bordeaux, Pôle Biologie et Pathologie, Service de Biologie des TumeursBordeaux, France
| | - Francis Mégraud
- Institut National de la Santé et de la Recherche Médicale, UMR1053 Bordeaux Research in Translational Oncology, BaRITOnBordeaux, France
- UMR1053 Bordeaux Research in Translational Oncology, BaRITOn, Université de BordeauxBordeaux, France
| | - Christine Varon
- Institut National de la Santé et de la Recherche Médicale, UMR1053 Bordeaux Research in Translational Oncology, BaRITOnBordeaux, France
- UMR1053 Bordeaux Research in Translational Oncology, BaRITOn, Université de BordeauxBordeaux, France
| | - Armelle Ménard
- Institut National de la Santé et de la Recherche Médicale, UMR1053 Bordeaux Research in Translational Oncology, BaRITOnBordeaux, France
- UMR1053 Bordeaux Research in Translational Oncology, BaRITOn, Université de BordeauxBordeaux, France
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11
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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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12
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Li G, Niu H, Zhang Y, Li Y, Xie F, Langford PR, Liu S, Wang C. Haemophilus parasuis cytolethal distending toxin induces cell cycle arrest and p53-dependent apoptosis. PLoS One 2017; 12:e0177199. [PMID: 28545143 PMCID: PMC5436662 DOI: 10.1371/journal.pone.0177199] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 04/24/2017] [Indexed: 01/20/2023] Open
Abstract
Haemophilus parasuis is the causative agent of Glasser’s disease in pigs. Cytolethal distending toxin (CDT) is an important virulence factor of H. parasuis. It is composed of three subunits: CdtA, CdtB and CdtC and all were successfully expressed in soluble form in Escherichia coli when the signal peptides were removed. Purified CdtB had DNase activity, i.e. caused DNA double strand damage, in vitro and in vivo prior to cell arrest and apoptosis. Flow cytometry analysis showed CdtB alone could induce cell cycle arrest and apoptosis in PK-15 porcine kidney and pulmonary alveolar macrophage (PAM) cells, which could be enhanced by CdtA or/and CdtC. CDT holotoxin could lead to significant cell distension, G2 arrest and apoptotic death in PK-15 and PAM cells. The apoptosis induced by CDT holotoxin was significantly inhibited by pifithrin-α, which indicates that it is p53-dependent. The results suggest that H. parasuis CDT holotoxin is a major virulence factor.
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Affiliation(s)
- Gang Li
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Hui Niu
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Yanhe Zhang
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Yanling Li
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Fang Xie
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Paul R. Langford
- Section of Paediatrics, Department of Medicine, Imperial College London, St. Mary’s Campus, London, United Kingdom
| | - Siguo Liu
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Chunlai Wang
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
- * E-mail:
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13
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Kalisperati P, Spanou E, Pateras IS, Korkolopoulou P, Varvarigou A, Karavokyros I, Gorgoulis VG, Vlachoyiannopoulos PG, Sougioultzis S. Inflammation, DNA Damage, Helicobacter pylori and Gastric Tumorigenesis. Front Genet 2017; 8:20. [PMID: 28289428 PMCID: PMC5326759 DOI: 10.3389/fgene.2017.00020] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 02/08/2017] [Indexed: 12/13/2022] Open
Abstract
Helicobacter pylori (H. pylori) is a Gram negative bacterium that colonizes the stomach of almost half human population. It has evolved to escape immune surveillance, establishes lifelong inflammation, predisposing to genomic instability and DNA damage, notably double strand breaks. The epithelial host cell responds by activation of DNA damage repair (DDR) machinery that seems to be compromised by the infection. It is therefore now accepted that genetic damage is a major mechanism operating in cases of H. pylori induced carcinogenesis. Here, we review the data on the molecular pathways involved in DNA damage and DDR activation during H. pylori infection.
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Affiliation(s)
- Polyxeni Kalisperati
- Gastroenterology Unit, Department of Pathophysiology, School of Medicine, National and Kapodistrian University Athens, Greece
| | - Evangelia Spanou
- Gastroenterology Unit, Department of Pathophysiology, School of Medicine, National and Kapodistrian University Athens, Greece
| | - Ioannis S Pateras
- Department of Histology and Embryology, School of Medicine, National and Kapodistrian University Athens, Greece
| | - Penelope Korkolopoulou
- 1st Department of Pathology, Laiko Hospital, School of Medicine, National and Kapodistrian University of Athens Athens, Greece
| | | | - Ioannis Karavokyros
- 1st Department of Surgery, Laiko Hospital, University of Athens, School of Medicine Athens, Greece
| | - Vassilis G Gorgoulis
- Department of Histology and Embryology, School of Medicine, National and Kapodistrian UniversityAthens, Greece; Biomedical Research Foundation of the Academy of AthensAthens, Greece; Faculty of Biology, Medicine and Health Manchester Cancer Research Centre, Manchester Academic Health Sciences Centre, The University of ManchesterManchester, UK
| | | | - Stavros Sougioultzis
- Gastroenterology Unit, Department of Pathophysiology, School of Medicine, National and Kapodistrian University Athens, Greece
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14
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Ge Z, Feng Y, Ge L, Parry N, Muthupalani S, Fox JG. Helicobacter hepaticus cytolethal distending toxin promotes intestinal carcinogenesis in 129Rag2-deficient mice. Cell Microbiol 2017; 19. [PMID: 28111881 DOI: 10.1111/cmi.12728] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 12/29/2016] [Accepted: 01/18/2017] [Indexed: 12/15/2022]
Abstract
Multiple pathogenic Gram-negative bacteria produce the cytolethal distending toxin (CDT) with activity of DNase I; CDT can induce DNA double-strand breaks (DSBs), G2/M cell cycle arrest, and apoptosis in cultured mammalian cells. However, the link of CDT to in vivo tumorigenesis is not fully understood. In this study, 129/SvEv Rag2-/- mice were gavaged with wild-type Helicobacter hepatics 3B1(Hh) and its isogenic cdtB mutant HhcdtBm7, followed by infection for 10 and 20 weeks (WPI). HhCDT deficiency did not affect cecal colonization levels of HhcdtBm7, but attenuated severity of cecal pathology in HhcdtBm7-infected mice. Of importance, preneoplasic dysplasia was progressed to cancer from 10 to 20 WPI in the Hh-infected mice but not in the HhcdtBm7-infected mice. In addition, the loss of HhCDT significantly dampened transcriptional upregulation of cecal Tnfα and Il-6, but elevated Il-10 mRNA levels when compared to Hh at 10 WPI. Furthermore, the presence of HhCDT increased numbers of lower bowel intestinal γH2AX-positive epithelial cells (a marker of DSBs) at both 10 and 20 WPI and augmented phospho-Stat3 foci+ intestinal crypts (activation of Stat3) at 20 WPI. Our findings suggest that CDT promoted Hh carcinogenesis by enhancing DSBs and activation of the Tnfα/Il-6-Stat3 signaling pathway.
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Affiliation(s)
- Zhongming Ge
- Division of Comparative Medicine, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA02139, USA
| | - Yan Feng
- Division of Comparative Medicine, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA02139, USA
| | - Lili Ge
- Division of Comparative Medicine, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA02139, USA
| | - Nicola Parry
- Division of Comparative Medicine, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA02139, USA
| | - Sureshkumar Muthupalani
- Division of Comparative Medicine, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA02139, USA
| | - James G Fox
- Division of Comparative Medicine, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA02139, USA
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15
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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: 132] [Impact Index Per Article: 18.9] [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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16
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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: 55] [Impact Index Per Article: 6.9] [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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17
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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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18
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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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19
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Streptococcus pneumoniae secretes hydrogen peroxide leading to DNA damage and apoptosis in lung cells. Proc Natl Acad Sci U S A 2015; 112:E3421-30. [PMID: 26080406 DOI: 10.1073/pnas.1424144112] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Streptococcus pneumoniae is a leading cause of pneumonia and one of the most common causes of death globally. The impact of S. pneumoniae on host molecular processes that lead to detrimental pulmonary consequences is not fully understood. Here, we show that S. pneumoniae induces toxic DNA double-strand breaks (DSBs) in human alveolar epithelial cells, as indicated by ataxia telangiectasia mutated kinase (ATM)-dependent phosphorylation of histone H2AX and colocalization with p53-binding protein (53BP1). Furthermore, results show that DNA damage occurs in a bacterial contact-independent fashion and that Streptococcus pyruvate oxidase (SpxB), which enables synthesis of H2O2, plays a critical role in inducing DSBs. The extent of DNA damage correlates with the extent of apoptosis, and DNA damage precedes apoptosis, which is consistent with the time required for execution of apoptosis. Furthermore, addition of catalase, which neutralizes H2O2, greatly suppresses S. pneumoniae-induced DNA damage and apoptosis. Importantly, S. pneumoniae induces DSBs in the lungs of animals with acute pneumonia, and H2O2 production by S. pneumoniae in vivo contributes to its genotoxicity and virulence. One of the major DSBs repair pathways is nonhomologous end joining for which Ku70/80 is essential for repair. We find that deficiency of Ku80 causes an increase in the levels of DSBs and apoptosis, underscoring the importance of DNA repair in preventing S. pneumoniae-induced genotoxicity. Taken together, this study shows that S. pneumoniae-induced damage to the host cell genome exacerbates its toxicity and pathogenesis, making DNA repair a potentially important susceptibility factor in people who suffer from pneumonia.
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20
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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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21
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Jiang Q, Huang YQ, Huang ZS. Relationship between Helicobacter hepaticus infection and hepatocellular carcinoma. Shijie Huaren Xiaohua Zazhi 2014; 22:1959-1965. [DOI: 10.11569/wcjd.v22.i14.1959] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Hepatocellular carcinoma (HCC) has a high incidence worldwide, with a low diagnostic rate in the early period and therefore a high death rate. Causes for some cases of liver cancer are not completely clear. The finding that the rate of liver cancer in male A/Jr mice is significantly higher makes researchers realize that Helicobacter hepaticus may cause HCC in human beings. To get a new perspective for exploring causes of liver cancer, this paper introduces the biological nature of and detecting methods for Helicobacter hepaticus, as well as the relationship between Helicobacter hepaticus infection and HCC. Helicobacter hepaticus infection may play an important role in some HCC cases.
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22
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Liyanage NP, Dassanayake RP, Kuszynski CA, Duhamel GE. Contribution of Helicobacter hepaticus cytolethal distending toxin subunits to human epithelial cell cycle arrest and apoptotic death in vitro. Helicobacter 2013; 18:433-43. [PMID: 23895367 PMCID: PMC3808484 DOI: 10.1111/hel.12084] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Cytolethal distending toxin (CDT) is the only known virulence factor found in H. hepaticus, the cause of chronic typhlocolitis and hepatitis leading to colonic and hepatocellular carcinomas in mice. Interaction of the tripartite polypeptide CdtA, CdtB, and CdtC subunits produced by H. hepaticus CDT (HhepCDT) causes cell cycle arrest and apoptotic death of cultured cells; however, the contribution of individual subunit to these processes has not been investigated. MATERIALS AND METHODS The temporal relationship between cell cycle and apoptotic death of human epithelial HeLa and INT407 cells intoxicated with HhepCDT holotoxin or reconstituted recombinant HhepCDT was compared by flow cytometry. The genotoxic activity of individual and combinations of recombinant HhepCDT protein subunits or increasing concentrations of individual recombinant HhepCDT protein subunits transfected into HeLa cells was assessed at 72 hours post-treatment by flow cytometry. RESULTS Similar time course of HhepCDT-induced G2 /M cell cycle arrest and apoptotic death was found with both cell lines which reached a maximum at 72 hours. The presence of all three HhepCDT subunits was required for maximum cell cycle arrest and apoptosis of both cell lines. Transfection of HeLa cells with HhepCdtB, but not with HhepCdtA or HhepCdtC, resulted in a dose-dependent G2 /M arrest and apoptotic death. CONCLUSION All three subunits of HhepCDT are required for maximum epithelial cell cycle arrest and progression to apoptotic death, and HhepCdtB subunit alone is necessary and sufficient for epithelial cell genotoxicity.
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Affiliation(s)
- Namal P.M. Liyanage
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68583, U.S.A
| | - Rohana P. Dassanayake
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68583, U.S.A
| | - Charles A. Kuszynski
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198, U.S.A
| | - Gerald E. Duhamel
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68583, U.S.A
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23
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The Role of Bacteria in Cancer Development. Infect Agent Cancer 2013. [DOI: 10.1007/978-94-007-5955-8_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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24
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Fedor Y, Vignard J, Nicolau-Travers ML, Boutet-Robinet E, Watrin C, Salles B, Mirey G. From single-strand breaks to double-strand breaks during S-phase: a new mode of action of theEscherichia coli Cytolethal Distending Toxin. Cell Microbiol 2012; 15:1-15. [DOI: 10.1111/cmi.12028] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 09/04/2012] [Accepted: 09/05/2012] [Indexed: 12/12/2022]
Affiliation(s)
- Y. Fedor
- INRA; UMR1331; Toxalim; Research Centre in Food Toxicology; F-31027 Toulouse France
- Université de Toulouse; UPS, UMR1331, Toxalim; F-31062 Toulouse France
| | - J. Vignard
- INRA; UMR1331; Toxalim; Research Centre in Food Toxicology; F-31027 Toulouse France
- Université de Toulouse; UPS, UMR1331, Toxalim; F-31062 Toulouse France
| | - M.-L. Nicolau-Travers
- INRA; UMR1331; Toxalim; Research Centre in Food Toxicology; F-31027 Toulouse France
- Université de Toulouse; UPS, UMR1331, Toxalim; F-31062 Toulouse France
| | - E. Boutet-Robinet
- INRA; UMR1331; Toxalim; Research Centre in Food Toxicology; F-31027 Toulouse France
- Université de Toulouse; UPS, UMR1331, Toxalim; F-31062 Toulouse France
| | - C. Watrin
- INRA; USC 1360; F-31300 Toulouse France
- Université de Toulouse; UPS; Centre de Physiopathologie de Toulouse Purpan (CPTP); F-31400 Toulouse France
- Inserm; UMR1043; F-31300 Toulouse France
- CNRS; UMR5282; F-31400 Toulouse France
| | - B. Salles
- INRA; UMR1331; Toxalim; Research Centre in Food Toxicology; F-31027 Toulouse France
- Université de Toulouse; UPS, UMR1331, Toxalim; F-31062 Toulouse France
| | - G. Mirey
- INRA; UMR1331; Toxalim; Research Centre in Food Toxicology; F-31027 Toulouse France
- Université de Toulouse; UPS, UMR1331, Toxalim; F-31062 Toulouse France
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25
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Treuting PM, Clifford CB, Sellers RS, Brayton CF. Of mice and microflora: considerations for genetically engineered mice. Vet Pathol 2011; 49:44-63. [PMID: 22173977 DOI: 10.1177/0300985811431446] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The phenotype of genetically engineered mice is a combination of both genetic and environmental factors that include the microflora of the mouse. The impact a particular microbe has on a mouse reflects the host-microbe interaction within the context of the mouse genotype and environment. Although often considered a confounding variable, many host-microbe interactions have resulted in the generation of novel model systems and characterization of new microbial agents. Microbes associated with overt disease in mice have been the historical focus of the laboratory animal medical and pathology community and literature. The advent of genetic engineering and the complex of mouse models have revealed previously unknown or disregarded agents that now oblige the attention of the biomedical research community. The purpose of this article is to describe and illustrate how phenotypes can be affected by microflora by focusing on the infectious diseases present in genetically engineered mouse (GEM) colonies of our collective institutions and by reviewing important agents that are rarely seen in most research facilities today. The goal is to introduce the concept of the role of microflora on phenotypes and in translational research using GEM models.
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Affiliation(s)
- P M Treuting
- Department of Comparative Medicine & Histology and Imaging Core, School of Medicine, University of Washington, T140 Health Science Center, Box 357190, Seattle, WA 98195-7190, USA.
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26
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Carcinogenic bacterial pathogen Helicobacter pylori triggers DNA double-strand breaks and a DNA damage response in its host cells. Proc Natl Acad Sci U S A 2011; 108:14944-9. [PMID: 21896770 DOI: 10.1073/pnas.1100959108] [Citation(s) in RCA: 230] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The bacterial pathogen Helicobacter pylori chronically infects the human gastric mucosa and is the leading risk factor for the development of gastric cancer. The molecular mechanisms of H. pylori-associated gastric carcinogenesis remain ill defined. In this study, we examined the possibility that H. pylori directly compromises the genomic integrity of its host cells. We provide evidence that the infection introduces DNA double-strand breaks (DSBs) in primary and transformed murine and human epithelial and mesenchymal cells. The induction of DSBs depends on the direct contact of live bacteria with mammalian cells. The infection-associated DNA damage is evident upon separation of nuclear DNA by pulse field gel electrophoresis and by high-magnification microscopy of metaphase chromosomes. Bacterial adhesion (e.g., via blood group antigen-binding adhesin) is required to induce DSBs; in contrast, the H. pylori virulence factors vacuolating cytotoxin A, γ-glutamyl transpeptidase, and the cytotoxin-associated gene (Cag) pathogenicity island are dispensable for DSB induction. The DNA discontinuities trigger a damage-signaling and repair response involving the sequential ataxia telangiectasia mutated (ATM)-dependent recruitment of repair factors--p53-binding protein (53BP1) and mediator of DNA damage checkpoint protein 1 (MDC1)--and histone H2A variant X (H2AX) phosphorylation. Although most breaks are repaired efficiently upon termination of the infection, we observe that prolonged active infection leads to saturation of cellular repair capabilities. In summary, we conclude that DNA damage followed by potentially imprecise repair is consistent with the carcinogenic properties of H. pylori and with its mutagenic properties in vitro and in vivo and may contribute to the genetic instability and frequent chromosomal aberrations that are a hallmark of gastric cancer.
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Smet A, Flahou B, Mukhopadhya I, Ducatelle R, Pasmans F, Haesebrouck F, Hold GL. The other Helicobacters. Helicobacter 2011; 16 Suppl 1:70-5. [PMID: 21896089 DOI: 10.1111/j.1523-5378.2011.00884.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The last year has seen an interesting and important collection of evidence presented in the field of the "other" than Helicobacter pylori Helicobacters. Associations with adult ulcerative colitis and biliary/hepatic disease have been described. New insights into the immune response and subsequent pathogenesis associated with infection have also been published. Genomic advances include description of new and unique species and the complete genome description for both Helicobacter felis and Helicobacter suis. Molecular studies have also elucidated the mechanism of action of some functional components of these organisms.
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Affiliation(s)
- Annemieke Smet
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
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Jinadasa RN, Bloom SE, Weiss RS, Duhamel GE. Cytolethal distending toxin: a conserved bacterial genotoxin that blocks cell cycle progression, leading to apoptosis of a broad range of mammalian cell lineages. MICROBIOLOGY-SGM 2011; 157:1851-1875. [PMID: 21565933 DOI: 10.1099/mic.0.049536-0] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Cytolethal distending toxin (CDT) is a heterotrimeric AB-type genotoxin produced by several clinically important Gram-negative mucocutaneous bacterial pathogens. Irrespective of the bacterial species of origin, CDT causes characteristic and irreversible cell cycle arrest and apoptosis in a broad range of cultured mammalian cell lineages. The active subunit CdtB has structural homology with the phosphodiesterase family of enzymes including mammalian DNase I, and alone is necessary and sufficient to account for cellular toxicity. Indeed, mammalian cells treated with CDT initiate a DNA damage response similar to that elicited by ionizing radiation-induced DNA double strand breaks resulting in cell cycle arrest and apoptosis. The mechanism of CDT-induced apoptosis remains incompletely understood, but appears to involve both p53-dependent and -independent pathways. While epithelial, endothelial and fibroblast cell lines respond to CDT by undergoing arrest of cell cycle progression resulting in nuclear and cytoplasmic distension that precedes apoptotic cell death, cells of haematopoietic origin display rapid apoptosis following a brief period of cell cycle arrest. In this review, the ecology of pathogens producing CDT, the molecular biology of bacterial CDT and the molecular mechanisms of CDT-induced cytotoxicity are critically appraised. Understanding the contribution of a broadly conserved bacterial genotoxin that blocks progression of the mammalian cell cycle, ultimately causing cell death, should assist with elucidating disease mechanisms for these important pathogens.
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Affiliation(s)
- Rasika N Jinadasa
- Department of Biomedical Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Stephen E Bloom
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
| | - Robert S Weiss
- Department of Biomedical Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Gerald E Duhamel
- Department of Biomedical Sciences, Cornell University, Ithaca, NY 14853, USA
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Fox JG, Ge Z, Whary MT, Erdman SE, Horwitz BH. Helicobacter hepaticus infection in mice: models for understanding lower bowel inflammation and cancer. Mucosal Immunol 2011; 4:22-30. [PMID: 20944559 PMCID: PMC3939708 DOI: 10.1038/mi.2010.61] [Citation(s) in RCA: 139] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Pioneering work in the 1990s first linked a novel microaerobic bacterium, Helicobacter hepaticus, with chronic active hepatitis and inflammatory bowel disease in several murine models. Targeted H. hepaticus infection experiments subsequently demonstrated its ability to induce colitis, colorectal cancer, and extraintestinal diseases in a number of mouse strains with defects in immune function and/or regulation. H. hepaticus is now widely utilized as a model system to dissect how intestinal microbiota interact with the host to produce both inflammatory and tolerogenic responses. This model has been used to make important advances in understanding factors that regulate both acquired and innate immune response within the intestine. Further, it has been an effective tool to help define the function of regulatory T cells, including their ability to directly inhibit the innate inflammatory response to gut microbiota. The complete genomic sequence of H. hepaticus has advanced the identification of several virulence factors and aided in the elucidation of H. hepaticus pathogenesis. Delineating targets of H. hepaticus virulence factors could facilitate novel approaches to treating microbially induced lower bowel inflammatory diseases.
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Affiliation(s)
- JG Fox
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA,Corresponding author. Mailing address: Division of Comparative Medicine, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Building 16-825, Cambridge, MA 02139. Phone (617) 253-1735. Fax: (617) 258-5708.
| | - Z Ge
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA
| | - MT Whary
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA
| | - SE Erdman
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA
| | - BH Horwitz
- Department of Pathology, Brigham and Women’s Hospital, Boston, MA
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