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Connolly SM, Erwin AL, Sabb M, Hanks JL, Chang L, Torrez RM, Caso GC, Campbell AM, Mosalaganti S, Cover TL, Ohi MD. Structural Analysis of Membrane-associated Forms of Helicobacter pylori VacA Toxin. J Mol Biol 2024; 436:168432. [PMID: 38161000 PMCID: PMC11090358 DOI: 10.1016/j.jmb.2023.168432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 11/27/2023] [Accepted: 12/27/2023] [Indexed: 01/03/2024]
Abstract
Helicobacter pylori colonizes the stomach in about half of the human population, leading to an increased risk of peptic ulcer disease and gastric cancer. H. pylori secretes an 88 kDa VacA toxin that contributes to pathogenesis. VacA assembles into oligomeric complexes in solution and forms anion-selective channels in cell membranes. Cryo-electron microscopy (cryo-EM) analyses of VacA oligomers in solution provided insights into VacA oligomerization but failed to reveal the structure of the hydrophobic N-terminal region predicted to be a pore-forming domain. In this study, we incubated VacA with liposomes and used single particle cryo-EM to analyze detergent-extracted VacA oligomers. A 3D structure of detergent-solubilized VacA hexamers revealed the presence of six α-helices extending from the center of the oligomers, a feature not observed in previous studies of water-soluble VacA oligomers. Cryo-electron tomography analysis and 2D averages of VacA associated with liposomes confirmed that central regions of the membrane-associated VacA oligomers can insert into the lipid bilayer. However, insertion is heterogenous, with some membrane-associated oligomers appearing only partially inserted and others sitting on top of the bilayer. These studies indicate that VacA undergoes a conformational change when contacting the membrane and reveal an α-helical region positioned to extend into the membrane. Although the reported VacA 3D structure does not represent a selective anion channel, our combined single particle 3D analysis, cryo-electron tomography, and modeling allow us to propose a model for the structural organization of the VacA N-terminus in the context of a hexamer as it inserts into the membrane.
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Affiliation(s)
- Sarah M Connolly
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Amanda L Erwin
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA; Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Megan Sabb
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Jessica L Hanks
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Louise Chang
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Rachel M Torrez
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Georgia C Caso
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA; Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Anne M Campbell
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Shyamal Mosalaganti
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA; Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Timothy L Cover
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA; Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA; Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN, USA.
| | - Melanie D Ohi
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA; Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
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Jarzab M, Skorko-Glonek J. There Are No Insurmountable Barriers: Passage of the Helicobacter pylori VacA Toxin from Bacterial Cytoplasm to Eukaryotic Cell Organelle. MEMBRANES 2023; 14:11. [PMID: 38248700 PMCID: PMC10821523 DOI: 10.3390/membranes14010011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 12/20/2023] [Accepted: 12/23/2023] [Indexed: 01/23/2024]
Abstract
The Gram-negative bacterium Helicobacter pylori is a very successful pathogen, one of the most commonly identified causes of bacterial infections in humans worldwide. H. pylori produces several virulence factors that contribute to its persistence in the hostile host habitat and to its pathogenicity. The most extensively studied are cytotoxin-associated gene A (CagA) and vacuolating cytotoxin A (VacA). VacA is present in almost all H. pylori strains. As a secreted multifunctional toxin, it assists bacterial colonization, survival, and proliferation during long-lasting infections. To exert its effect on gastric epithelium and other cell types, VacA undergoes several modifications and crosses multiple membrane barriers. Once inside the gastric epithelial cell, VacA disrupts many cellular-signaling pathways and processes, leading mainly to changes in the efflux of various ions, the depolarization of membrane potential, and perturbations in endocytic trafficking and mitochondrial function. The most notable effect of VacA is the formation of vacuole-like structures, which may lead to apoptosis. This review focuses on the processes involved in VacA secretion, processing, and entry into host cells, with a particular emphasis on the interaction of the mature toxin with host membranes and the formation of transmembrane pores.
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Affiliation(s)
| | - Joanna Skorko-Glonek
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland;
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Kaneko K, Zaitoun AM, Letley DP, Rhead JL, Torres J, Spendlove I, Atherton JC, Robinson K. The active form of Helicobacter pylori vacuolating cytotoxin induces decay-accelerating factor CD55 in association with intestinal metaplasia in the human gastric mucosa. J Pathol 2022; 258:199-209. [PMID: 35851954 PMCID: PMC9543990 DOI: 10.1002/path.5990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 06/27/2022] [Accepted: 07/15/2022] [Indexed: 11/19/2022]
Abstract
High-level expression of decay-accelerating factor, CD55, has previously been found in human gastric cancer (GC) and intestinal metaplasia (IM) tissues. Therapeutic effects of CD55 inhibition in cancer have been reported. However, the role of Helicobacter pylori infection and virulence factors in the induction of CD55 and its association with histological changes of the human gastric mucosa remain incompletely understood. We hypothesised that CD55 would be increased during infection with more virulent strains of H. pylori, and with more marked gastric mucosal pathology. RT-qPCR and immunohistochemical analyses of gastric biopsy samples from 42 H. pylori-infected and 42 uninfected patients revealed that CD55 mRNA and protein were significantly higher in the gastric antrum of H. pylori-infected patients, and this was associated with the presence of IM, but not atrophy, or inflammation. Increased gastric CD55 and IM were both linked with colonisation by vacA i1-type strains independently of cagA status, and in vitro studies using isogenic mutants of vacA confirmed the ability of VacA to induce CD55 and sCD55 in gastric epithelial cell lines. siRNA experiments to investigate the function of H. pylori-induced CD55 showed that CD55 knockdown in gastric epithelial cells partially reduced IL-8 secretion in response to H. pylori, but this was not due to modulation of bacterial adhesion or cytotoxicity. Finally, plasma samples taken from the same patients were analysed for the soluble form of CD55 (sCD55) by ELISA. sCD55 levels were not influenced by IM and did not correlate with gastric CD55 mRNA levels. These results suggest a new link between active vacA i1-type H. pylori, IM, and CD55, and identify CD55 as a molecule of potential interest in the management of IM as well as GC treatment. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Kazuyo Kaneko
- Nottingham Digestive Diseases Biomedical Research CentreNottingham University Hospitals NHS Trust and University of NottinghamNottinghamUK
| | - Abed M Zaitoun
- Department of Cellular PathologyNottingham University Hospitals NHS Trust, Queen's Medical Centre CampusNottinghamUK
| | - Darren P Letley
- Nottingham Digestive Diseases Biomedical Research CentreNottingham University Hospitals NHS Trust and University of NottinghamNottinghamUK
| | - Joanne L Rhead
- Nottingham Digestive Diseases Biomedical Research CentreNottingham University Hospitals NHS Trust and University of NottinghamNottinghamUK
| | - Javier Torres
- Unidad de Investigación en Enfermedades InfecciosasHospital de Pediatría, Centro Médico Nacional Siglo XXI, IMSSMexico CityMexico
| | - Ian Spendlove
- Division of Cancer and Stem Cells, School of MedicineUniversity of Nottingham Biodiscovery InstituteNottinghamUK
| | - John C Atherton
- Nottingham Digestive Diseases Biomedical Research CentreNottingham University Hospitals NHS Trust and University of NottinghamNottinghamUK
| | - Karen Robinson
- Nottingham Digestive Diseases Biomedical Research CentreNottingham University Hospitals NHS Trust and University of NottinghamNottinghamUK
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Karbalaei M, Talebi Bezmin Abadi A, Keikha M. Clinical relevance of the cagA and vacA s1m1 status and antibiotic resistance in Helicobacter pylori: a systematic review and meta-analysis. BMC Infect Dis 2022; 22:573. [PMID: 35752757 PMCID: PMC9233856 DOI: 10.1186/s12879-022-07546-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 06/15/2022] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND The role of Helicobacter pylori (H. pylori) virulence factors of such as vacA s1m1 and cagA in designating clinical outcomes and eradication rate has been deeply challenged in the last decade. The goal of this analysis was to identify the potential relevance between cagA and vacA genotypes with reported antibiotic resistance observed in clinical H. pylori isolates. METHODS This literature search was conducted in databases such as Clarivate analytics, PubMed, Scopus, EMBASE, DOAJ, and Google Scholar by April 2022, regardless of language restrictions and publication date. Quality of the included studies was assessed by the Newcastle-Ottawa scale. Statistical analysis of retrieved studies was fulfilled using Comprehensive Meta-Analysis software version 2.2. Following quality appraisal of eligible studies, potential association between the status of cagA and vacA genes with resistance to clarithromycin, metronidazole, amoxicillin, tetracycline, and levofloxacin was measured using odds ratio with 95% confidence interval. We also used sensitivity analyses and meta-regression to eliminate the source of heterogeneity from the overall estimates. Publication bias was assessed using funnel plot, Egger's test, Begg's test with the trim and fill procedure to assess the presence and magnitude of publication bias in the included studies. RESULTS Our findings suggested that a significant relationship between cagA status and increase resistance to metronidazole (OR: 2.69; 95% CI: 1.24-5.83). In subgroup analysis, we found that in the Western population, infection with cagA-positive strains could be led to increase in the resistance to metronidazole (OR: 1.59; 95% CI: 0.78-3.21), amoxicillin (OR: 19.68; 95% CI: 2.74-141.18), and levofloxacin (OR: 11.33; 95% CI: 1.39-91.85). After implementation of trim and fill method, the adjusted OR was not significantly differed from original estimates which in turn represented our subgroup analysis was statistically robust. On the other hand, vacA genotypes usually reduce the antibiotic resistance of this bacterium, so that vacA s1m1 significantly reduces the resistance to metronidazole (OR: 0.41; 95% CI: 0.20-0.86). Surprisingly, resistance of vacA s2m2 strains to antibiotics was low, the reason may be due to the non-inflammatory properties of strains containing vacA s2m2. The meta-regression and sensitivity analyses successfully reduced the effect of heterogeneity from the overall estimates. In addition, although the pooled OR is reduced after trim and fill adjustment but results do not change the conclusion regarding vacA genotypes and antibiotic resistance. CONCLUSIONS According to our findings, it was clearly demonstrated that cagA-positive strains are resistance to metronidazole, especially in Western countries. In Western countries, vacA s1m1 increases resistance to amoxicillin and levofloxacin. Based on the present findings, the vacA s1m1 genotype significantly increases resistance to metronidazole, while the vacA s1m2 decreases resistance to clarithromycin and metronidazole. Resistance to antibiotics in less virulent (vacA s2m2) strains is statistically significant lower than others.
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Affiliation(s)
- Mohsen Karbalaei
- Department of Microbiology and Virology, School of Medicine, Jiroft University of Medical Sciences, Jiroft, Iran
| | - Amin Talebi Bezmin Abadi
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
| | - Masoud Keikha
- Department of Microbiology and Virology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
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Inflammation and Gastric Cancer. Diseases 2022; 10:diseases10030035. [PMID: 35892729 PMCID: PMC9326573 DOI: 10.3390/diseases10030035] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 06/16/2022] [Accepted: 06/19/2022] [Indexed: 11/17/2022] Open
Abstract
Gastric cancer remains a major killer globally, although its incidence has declined over the past century. It is the fifth most common cancer and the third most common reason for cancer-related deaths worldwide. Gastric cancer is the outcome of a complex interaction between environmental, host genetic, and microbial factors. There is significant evidence supporting the association between chronic inflammation and the onset of cancer. This association is particularly robust for gastrointestinal cancers in which microbial pathogens are responsible for the chronic inflammation that can be a triggering factor for the onset of those cancers. Helicobacter pylori is the most prominent example since it is the most widespread infection, affecting nearly half of the world’s population. It is well-known to be responsible for inducing chronic gastric inflammation progressing to atrophy, metaplasia, dysplasia, and eventually, gastric cancer. This review provides an overview of the association of the factors playing a role in chronic inflammation; the bacterial characteristics which are responsible for the colonization, persistence in the stomach, and triggering of inflammation; the microbiome involved in the chronic inflammation process; and the host factors that have a role in determining whether gastritis progresses to gastric cancer. Understanding these interconnections may improve our ability to prevent gastric cancer development and enhance our understanding of existing cases.
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Sharndama HC, Mba IE. Helicobacter pylori: an up-to-date overview on the virulence and pathogenesis mechanisms. Braz J Microbiol 2022; 53:33-50. [PMID: 34988937 PMCID: PMC8731681 DOI: 10.1007/s42770-021-00675-0] [Citation(s) in RCA: 72] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 12/24/2021] [Indexed: 02/06/2023] Open
Abstract
Helicobacter pylori is an organism associated with ulcer disease and gastric cancer. The latter is one of the most prevalent malignancies and currently the fourth major cause of cancer-related deaths globally. The pathogen infects about 50% of the world population, and currently, no treatment ensures its total elimination. There has been an increase in our understanding of the pathophysiology and pathogenesis mechanisms of H. pylori over the years. H. pylori can induce several genetic alterations, express numerous virulence factors, and trigger diverse adaptive mechanisms during its adherence and colonization. For successful colonization and infection establishment, several effector proteins/toxins are released by the organism. Evidence is also available reporting spiral to coccoid transition as a unique tactic H. pylori uses to survive in the host's gastrointestinal tract (GIT). Thus, the virulence and pathogenicity of H. pylori are under the control of complex interplay between the virulence factors, host, and environmental factors. Expounding the role of the various virulence factors in H. pylori pathogenesis and clinical outcomes is crucial for vaccine development and in providing and developing a more effective therapeutic intervention. Here we critically reflect on H. pylori infection and delineate what is currently known about the virulence and pathogenesis mechanisms of H. pylori.
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Affiliation(s)
| | - Ifeanyi Elibe Mba
- Department of Microbiology, University of Nigeria, Nsukka, Enugu, Nigeria.
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Sokolova O, Naumann M. Matrix Metalloproteinases in Helicobacter pylori-Associated Gastritis and Gastric Cancer. Int J Mol Sci 2022; 23:1883. [PMID: 35163805 PMCID: PMC8836485 DOI: 10.3390/ijms23031883] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 02/02/2022] [Accepted: 02/04/2022] [Indexed: 02/05/2023] Open
Abstract
Gastric cancer is one of the leading causes of the cancer-related mortality worldwide. The etiology of this disease is complex and involves genetic predisposition and environmental factors, including Helicobacter pylori. Infection of the stomach with H. pylori leads to gastritis and gastric atrophy, which can progress stepwise to gastric cancer. Matrix metalloproteinases (MMPs) actively participate in the pathology development. The further progression of gastric cancer seems to be less dependent on bacteria but of intra-tumor cell dynamics. Bioinformatics data confirmed an important role of the extracellular matrix constituents and specific MMPs in stomach carcinoma invasion and metastasis, and revised their potential as predictors of the disease outcome. In this review, we describe, in detail, the impact of MMPs in H. pylori-associated gastritis and gastric cancer.
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Affiliation(s)
- Olga Sokolova
- Institute of Experimental Internal Medicine, Medical Faculty, Otto von Guericke University, Leipziger Str. 44, 39120 Magdeburg, Germany
| | - Michael Naumann
- Institute of Experimental Internal Medicine, Medical Faculty, Otto von Guericke University, Leipziger Str. 44, 39120 Magdeburg, Germany
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8
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Abstract
Helicobacter pylori is present in approximately one-half of the world's population. There are significant differences in prevalence based on region, age, race/ethnicity, and socioeconomic status. H pylori is the most common cause of infection-related cancers. Studies have demonstrated the relationship between H pylori infection and gastric adenocarcinoma and mucosa-associated lymphoid tissue lymphoma. H pylori has features and enzymatic properties allowing it to survive in the acidic stomach environment, and has specific virulence factors that promote an increased risk of gastric pathology. Eradication of H pylori is first-line therapy for mucosa-associated lymphoid tissue lymphoma and decreases the risk of gastric adenocarcinoma.
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Linn AK, Samainukul N, Sakdee S, Butnampetch C, Li HC, Angsuthanasombat C, Katzenmeier G. N-Terminally Added Tag Selectively Enhances Heterologous Expression of VacA Cytotoxin Variants from Helicobacter pylori. Protein Pept Lett 2021; 28:643-650. [PMID: 33183185 DOI: 10.2174/0929866527666201112122831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 09/18/2020] [Accepted: 09/28/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Gastric pathogen Helicobacter pylori secretes VacA cytotoxin displaying a high degree of polymorphic variations of which the highest VacA pathogenicity correlates with m1-type variant followed by VacA-m2. OBJECTIVE To comparatively evaluate expression in Escherichia coli of the mature VacA variants (m1- and m2-types) and their 33- and 55/59-kDa domains fused with His(6) tag at N- or C-terminus. METHODS All VacA clones expressed in E. coli TOP10™ were analyzed by SDS-PAGE and Western blotting. VacA inclusions were solubilized under native conditions (~150-rpm shaking at 37°C for 2 h in 20 mM HEPES (pH7.4) and 150 mM NaCl). Membrane-perturbing and cytotoxic activities of solubilized VacA proteins were assessed via liposome-entrapped dye leakage and resazurin- based cell viability assays, respectively. VacA binding to human gastric adenocarcinoma cells was assessed by immunofluorescence microscopy. Side-chain hydrophobicity of VacA was analyzed through modeled structures constructed by homology- and ab initio-based modeling. RESULTS Both full-length VacA-m1 and 33-kDa domain were efficiently expressed only in the presence of N-terminal extension while its 55-kDa domain was capably expressed with either N- or Cterminal extension. Selectively enhanced expression was also observed for VacA-m2. Protein expression profiles revealed a critical period in IPTG-induced production of the 55-kDa domain with N-terminal extension unlike its C-terminal extension showing relatively stable expression. Both VacA- m1 isolated domains were able to independently bind to cultured gastric cells similar to the full- length toxin, albeit the 33-kDa domain exhibited significantly higher activity of membrane perturbation than others. Membrane-perturbing and cytotoxic activities observed for VacA-m1 appeared to be higher than those of VacA-m2. Homology-based modeling and sequence analysis suggested a potential structural impact of non-polar residues located at the N-terminus of the mature VacA toxin and its 33-kDa domain. CONCLUSION Our data provide molecular insights into selective influence of the N-terminally added tag on efficient expression of recombinant VacA variants, signifying biochemical and biological implications of the hydrophobic stretch within the N-terminal domain.
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Affiliation(s)
- Aung Khine Linn
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Nitchakan Samainukul
- Bacterial Toxin Research Innovation Cluster (BRIC), Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom 73170, Thailand
| | - Somsri Sakdee
- Bacterial Toxin Research Innovation Cluster (BRIC), Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom 73170, Thailand
| | - Chonthicha Butnampetch
- Bacterial Toxin Research Innovation Cluster (BRIC), Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom 73170, Thailand
| | - Hui-Chun Li
- Department of Biochemistry, School of Medicine, Tzu Chi University, Hualian 97004, Taiwan
| | - Chanan Angsuthanasombat
- Bacterial Toxin Research Innovation Cluster (BRIC), Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom 73170, Thailand
| | - Gerd Katzenmeier
- Bacterial Toxin Research Innovation Cluster (BRIC), Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom 73170, Thailand
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Association of Helicobacter pylori Infection and Host Cytokine Gene Polymorphism with Gastric Cancer. Can J Gastroenterol Hepatol 2021; 2021:8810620. [PMID: 34136433 PMCID: PMC8177986 DOI: 10.1155/2021/8810620] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 05/18/2021] [Indexed: 12/13/2022] Open
Abstract
The global cancer burden of new cases of various types rose with millions of death in 2018. Based on the data extracted by GLOBOCAN 2018, gastric cancer (GC) is the third leading cause of mortality related to cancer across the globe. Carcinogenic or oncogenic infections associated with Helicobacter pylori (Hp) are regarded as one of the essential risk factors for GC development. It contributes to the increased production of cytokines that cause inflammation prior to their growth in the host cells. Hp infections and specific types of polymorphisms within the host cells encoding cytokines are significant contributors to the host's increased susceptibility in terms of the development of GC. Against the backdrop of such an observation is that only a small portion of the cells infected can become malignant. The diversities are a consequence of the differences in the pathogenic pathway of the Hp, susceptibility of the host, environmental conditions, and interplay between these factors. It is evident that hosts carrying cytokine genes with high inflammatory levels and polymorphism tend to exhibit an increased risk of development of GC, with special emphasis being placed on the host cytokines gene polymorphisms.
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Muñoz-Ramirez ZY, Pascoe B, Mendez-Tenorio A, Mourkas E, Sandoval-Motta S, Perez-Perez G, Morgan DR, Dominguez RL, Ortiz-Princz D, Cavazza ME, Rocha G, Queiroz DMM, Catalano M, Palma GZD, Goldman CG, Venegas A, Alarcon T, Oleastro M, Vale FF, Goodman KJ, Torres RC, Berthenet E, Hitchings MD, Blaser MJ, Sheppard SK, Thorell K, Torres J. A 500-year tale of co-evolution, adaptation, and virulence: Helicobacter pylori in the Americas. THE ISME JOURNAL 2021; 15:78-92. [PMID: 32879462 PMCID: PMC7853065 DOI: 10.1038/s41396-020-00758-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 07/27/2020] [Accepted: 08/24/2020] [Indexed: 02/07/2023]
Abstract
Helicobacter pylori is a common component of the human stomach microbiota, possibly dating back to the speciation of Homo sapiens. A history of pathogen evolution in allopatry has led to the development of genetically distinct H. pylori subpopulations, associated with different human populations, and more recent admixture among H. pylori subpopulations can provide information about human migrations. However, little is known about the degree to which some H. pylori genes are conserved in the face of admixture, potentially indicating host adaptation, or how virulence genes spread among different populations. We analyzed H. pylori genomes from 14 countries in the Americas, strains from the Iberian Peninsula, and public genomes from Europe, Africa, and Asia, to investigate how admixture varies across different regions and gene families. Whole-genome analyses of 723 H. pylori strains from around the world showed evidence of frequent admixture in the American strains with a complex mosaic of contributions from H. pylori populations originating in the Americas as well as other continents. Despite the complex admixture, distinctive genomic fingerprints were identified for each region, revealing novel American H. pylori subpopulations. A pan-genome Fst analysis showed that variation in virulence genes had the strongest fixation in America, compared with non-American populations, and that much of the variation constituted non-synonymous substitutions in functional domains. Network analyses suggest that these virulence genes have followed unique evolutionary paths in the American populations, spreading into different genetic backgrounds, potentially contributing to the high risk of gastric cancer in the region.
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Affiliation(s)
- Zilia Y Muñoz-Ramirez
- Unidad de Investigacion en Enfermedades Infecciosas, UMAE Pediatria, Instituto Mexicano del Seguro Social, Ciudad de México, Mexico
- Laboratorio de Bioinformática y Biotecnología Genómica, Escuela Nacional de Ciencias Biológicas, Unidad Profesional Lázaro Cárdenas, Instituto Politécnico Nacional, 11340, Mexico City, Mexico
| | - Ben Pascoe
- Department of Biology and Biochemistry, The Milner Centre for Evolution, University of Bath, Claverton Down, Bath, UK
| | - Alfonso Mendez-Tenorio
- Laboratorio de Bioinformática y Biotecnología Genómica, Escuela Nacional de Ciencias Biológicas, Unidad Profesional Lázaro Cárdenas, Instituto Politécnico Nacional, 11340, Mexico City, Mexico
| | - Evangelos Mourkas
- Department of Biology and Biochemistry, The Milner Centre for Evolution, University of Bath, Claverton Down, Bath, UK
| | - Santiago Sandoval-Motta
- Instituto Nacional de Medicina Genomica, Ciudad de México, México
- Consejo Nacional de Ciencia y Tecnologia, Catedras CONACYT, Ciudad de México, México
| | | | - Douglas R Morgan
- UAB Division of Gastroenterology and Hepatology, The University of Alabama at Birmingham, Birmingham, UK
- Division of Gastroenterology, Hepatology, and Nutrition, Vanderbilt University, Nashville, TN, USA
| | - Ricardo Leonel Dominguez
- Western Honduras Gastric Cancer Prevention Initiative Hospital de Occidente Santa Rosa de Copan, Santa Rosa de Copan, Honduras
| | - Diana Ortiz-Princz
- Laboratorio de Microbiología Molecular, Servicio Instituto de Biomedicina MPPS-UCV, Caracas, Venezuela
| | - Maria Eugenia Cavazza
- Laboratorio de Microbiología Molecular, Servicio Instituto de Biomedicina MPPS-UCV, Caracas, Venezuela
| | - Gifone Rocha
- Faculdade de Medicina da UFMG, Belo Horizonte, Brazil
| | | | - Mariana Catalano
- Facultad de Medicina, Instituto de Microbiología y Parasitología Médica (IMPAM, UBA-CONICET), Universidad de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas, Santa Rosa de Copan, Honduras
| | - Gerardo Zerbetto De Palma
- Instituto de Química y Fisicoquímica Biológicas "Prof. Alejandro C. Paladini", IQUIFIB UBA-CONICET, Santa Rosa de Copan, Honduras
| | - Cinthia G Goldman
- Facultad de Farmacia y Bioquímica, Cátedra de Física, Universidad de Buenos Aires, C1113AAD, Buenos Aires, Argentina
- National Scientific and Technical Research Council (CONICET), C1425FQB, Buenos Aires, Argentina
| | - Alejandro Venegas
- Laboratorio de Patogénesis Microbiana, Centro de Investigación Biomédica, Universidad Diego Portales, Ejército, 141, Santiago, Chile
| | - Teresa Alarcon
- Department of Microbiology, Hospital Universitario La Princesa, Instituto de Investigación Sanitaria Princesa, Madrid, Spain
| | - Monica Oleastro
- Host-Pathogen Interactions Unit, Faculty of Pharmacy, Research Institute for Medicines (iMed-ULisboa), Universidade de Lisboa, Lisboa, Portugal
| | - Filipa F Vale
- Host-Pathogen Interactions Unit, Faculty of Pharmacy, Research Institute for Medicines (iMed-ULisboa), Universidade de Lisboa, Lisboa, Portugal
| | - Karen J Goodman
- Division of Gastroenterology, Centre of Excellence for Gastrointestinal Inflammation & Immunity Research, University of Alberta, Edmonton, AB, Canada
| | - Roberto C Torres
- Unidad de Investigacion en Enfermedades Infecciosas, UMAE Pediatria, Instituto Mexicano del Seguro Social, Ciudad de México, Mexico
| | - Elvire Berthenet
- Swansea University Medical School, Swansea University, Swansea, UK
| | | | - Martin J Blaser
- Center for Advanced Biotechnology and Medicine, Rutgers University, New Brunswick, NJ, USA
| | - Samuel K Sheppard
- Department of Biology and Biochemistry, The Milner Centre for Evolution, University of Bath, Claverton Down, Bath, UK
| | - Kaisa Thorell
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
| | - Javier Torres
- Unidad de Investigacion en Enfermedades Infecciosas, UMAE Pediatria, Instituto Mexicano del Seguro Social, Ciudad de México, Mexico.
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12
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Functional Properties of Helicobacter pylori VacA Toxin m1 and m2 Variants. Infect Immun 2020; 88:IAI.00032-20. [PMID: 32284370 DOI: 10.1128/iai.00032-20] [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: 01/14/2020] [Accepted: 04/05/2020] [Indexed: 12/14/2022] Open
Abstract
Helicobacter pylori colonizes the gastric mucosa and secretes a pore-forming toxin (VacA). Two main types of VacA, m1 and m2, can be distinguished by phylogenetic analysis. Type m1 forms of VacA have been extensively studied, but there has been relatively little study of m2 forms. In this study, we generated H. pylori strains producing chimeric proteins in which VacA m1 segments of a parental strain were replaced by corresponding m2 sequences. In comparison to the parental m1 VacA protein, a chimeric protein (designated m2/m1) containing m2 sequences in the N-terminal portion of the m region was less potent in causing vacuolation of HeLa cells, AGS gastric cells, and AZ-521 duodenal cells and had reduced capacity to cause membrane depolarization or death of AZ-521 cells. Consistent with the observed differences in activity, the chimeric m2/m1 VacA protein bound to cells at reduced levels compared to the binding levels of the parental m1 protein. The presence of two strain-specific insertions or deletions within or adjacent to the m region did not influence toxin activity. Experiments with human gastric organoids grown as monolayers indicated that m1 and m2/m1 forms of VacA had similar cell-vacuolating activities. Interestingly, both forms of VacA bound preferentially to the basolateral surface of organoid monolayers and caused increased cell vacuolation when interacting with the basolateral surface compared to the apical surface. These data provide insights into functional correlates of sequence variation in the VacA midregion (m region).
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13
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Activity and Functional Importance of Helicobacter pylori Virulence Factors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1149:35-56. [PMID: 31016624 DOI: 10.1007/5584_2019_358] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Helicobacter pylori is a very successful Gram-negative pathogen colonizing the stomach of humans worldwide. Infections with this bacterium can generate pathologies ranging from chronic gastritis and peptic ulceration to gastric cancer. The best characterized H. pylori virulence factors that cause direct cell damage include an effector protein encoded by the cytotoxin-associated gene A (CagA), a type IV secretion system (T4SS) encoded in the cag-pathogenicity island (cag PAI), vacuolating cytotoxin A (VacA), γ-glutamyl transpeptidase (GGT), high temperature requirement A (HtrA, a serine protease) and cholesterol glycosyl-transferase (CGT). Since these H. pylori factors are either surface-exposed, secreted or translocated, they can directly interact with host cell molecules and are able to hijack cellular functions. Studies on these bacterial factors have progressed substantially in recent years. Here, we review the current status in the characterization of signaling cascades by these factors in vivo and in vitro, which comprise the disruption of cell-to-cell junctions, induction of membrane rearrangements, cytoskeletal dynamics, proliferative, pro-inflammatory, as well as, pro-apoptotic and anti-apoptotic responses or immune evasion. The impact of these signal transduction modules in the pathogenesis of H. pylori infections is discussed.
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14
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Rapid Characterization of Virulence Determinants in Helicobacter pylori Isolated from Non-Atrophic Gastritis Patients by Next-Generation Sequencing. J Clin Med 2019; 8:jcm8071030. [PMID: 31336977 PMCID: PMC6678415 DOI: 10.3390/jcm8071030] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 07/09/2019] [Indexed: 02/07/2023] Open
Abstract
Helicobacter pylori is a major human pathogen that causes a wide range of gastrointestinal pathology. Progression of H. pylori induced gastritis to more severe disease has been found to highly correlate with the array of virulence factors expressed by the pathogen. The objective of this study was twofold: first, to characterize the genetic diversity of H. pylori strains isolated from 41 non-atrophic gastritis patients in Switzerland, an issue that has not been investigated to date. And second, to assess the prevalence and sequence variation of H. pylori virulence factors (cagA, vacA, iceA and dupA) and genes encoding outer membrane proteins (OMPs; babA, babB, sabA, sabB, hopZ, hopQ and oipA) by whole genome sequencing (WGS) using an Illumina MiSeq platform. WGS identified high genetic diversity in the analyzed H. pylori strains. Most H. pylori isolates were assigned to hpEurope (95.0%, 39/41), and the remaining ones (5.0%, 2/41) to hpEastAsia, subpopulation hspEAsia. Analysis of virulence factors revealed that 43.9% of the strains were cagA-positive, and the vacA s1 allele was detected in 56.0% of the isolates. The presence of cagA was found to be significantly associated (P < 0.001) with the presence of vacA s1, babA2 and hopQ allele 1 as well as expression of oipA. Moreover, we found an association between the grade of gastritis and H. pylori abundance in the gastric mucosa, respectively and the presence of cagA, vacA s1 and hopQ allele 1. Among our 41 gastritis patients, we identified seven patients infected with H. pylori strains that carried a specific combination of virulence factors (i.e., cagA, vacA s1 allele and babA2 allele), recently implicated in the development of more severe gastrointestinal pathology, like peptic ulcer disease and even gastric cancer. To this end, WGS can be employed for rapid and detailed characterization of virulence determinants in H. pylori, providing valuable insights into the pathogenic capacity of the bacterium. This could ultimately lead to a higher level of personalized treatment and management of patients suffering from H. pylori associated infections.
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15
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McClain MS, Beckett AC, Cover TL. Helicobacter pylori Vacuolating Toxin and Gastric Cancer. Toxins (Basel) 2017; 9:toxins9100316. [PMID: 29023421 PMCID: PMC5666363 DOI: 10.3390/toxins9100316] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 10/03/2017] [Accepted: 10/05/2017] [Indexed: 12/13/2022] Open
Abstract
Helicobacter pylori VacA is a channel-forming toxin unrelated to other known bacterial toxins. Most H. pylori strains contain a vacA gene, but there is marked variation among strains in VacA toxin activity. This variation is attributable to strain-specific variations in VacA amino acid sequences, as well as variations in the levels of VacA transcription and secretion. In this review, we discuss epidemiologic studies showing an association between specific vacA allelic types and gastric cancer, as well as studies that have used animal models to investigate VacA activities relevant to gastric cancer. We also discuss the mechanisms by which VacA-induced cellular alterations may contribute to the pathogenesis of gastric cancer.
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Affiliation(s)
- Mark S McClain
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
| | - Amber C Beckett
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
| | - Timothy L Cover
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN 37212, USA.
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16
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Al-Maleki AR, Loke MF, Lui SY, Ramli NSK, Khosravi Y, Ng CG, Venkatraman G, Goh KL, Ho B, Vadivelu J. Helicobacter pylori outer inflammatory protein A (OipA) suppresses apoptosis of AGS gastric cells in vitro. Cell Microbiol 2017; 19. [PMID: 28776327 DOI: 10.1111/cmi.12771] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 07/02/2017] [Accepted: 07/26/2017] [Indexed: 12/12/2022]
Abstract
Outer inflammatory protein A (OipA) is an important virulence factor associated with gastric cancer and ulcer development; however, the results have not been well established and turned out to be controversial. This study aims to elucidate the role of OipA in Helicobacter pylori infection using clinical strains harbouring oipA "on" and "off" motifs. Proteomics analysis was performed on AGS cell pre-infection and postinfection with H. pylori oipA "on" and "off" strains, using liquid chromatography/mass spectrometry. AGS apoptosis and cell cycle assays were performed. Moreover, expression of vacuolating cytotoxin A (VacA) was screened using Western blotting. AGS proteins that have been suggested previously to play a role or associated with gastric disease were down-regulated postinfection with oipA "off" strains comparing to oipA "on" strains. Furthermore, oipA "off" and ΔoipA cause higher level of AGS cells apoptosis and G0/G1 cell-cycle arrest than oipA "on" strains. Interestingly, deletion of oipA increased bacterial VacA production. The capability of H. pylori to induce apoptosis and suppress expression of proteins having roles in human disease in the absence of oipA suggests that strains not expressing OipA may be less virulent or may even be protective against carcinogenesis compared those expressing OipA. This potentially explains the higher incidence of gastric cancer in East Asia where oipA "on" strains predominates.
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Affiliation(s)
- Anis Rageh Al-Maleki
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Mun Fai Loke
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Sook Yin Lui
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Nur Siti Khadijah Ramli
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Yalda Khosravi
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Chow Goon Ng
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Gopinath Venkatraman
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Khean-Lee Goh
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Bow Ho
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Singapore Precision Medicine Centre Pte Ltd, Singapore, Singapore
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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17
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Safaralizadeh R, Dastmalchi N, Hosseinpourfeizi M, Latifi-Navid S. Helicobacter pylori virulence factors in relation to gastrointestinal diseases in Iran. Microb Pathog 2017; 105:211-217. [DOI: 10.1016/j.micpath.2017.02.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Revised: 02/15/2017] [Accepted: 02/17/2017] [Indexed: 02/08/2023]
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18
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El Khadir M, Alaoui Boukhris S, Benajah DA, El Rhazi K, Ibrahimi SA, El Abkari M, Harmouch T, Nejjari C, Mahmoud M, Benlemlih M, Bennani B. VacA and CagA Status as Biomarker of Two Opposite End Outcomes of Helicobacter pylori Infection (Gastric Cancer and Duodenal Ulcer) in a Moroccan Population. PLoS One 2017; 12:e0170616. [PMID: 28125638 PMCID: PMC5268467 DOI: 10.1371/journal.pone.0170616] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 01/06/2017] [Indexed: 12/13/2022] Open
Abstract
Helicobacter pylori (H. pylori) infection induces inflammation of the gastric mucosa, which may progress to precancerous lesions leading to gastric cancer. Pathological determinism is associated to some virulence genes of the bacterium, notably the vacA and cagA genes. The present study aimed to determine the H. pylori genotypes distribution and their association with sex, age and gastric diseases in a Moroccan population. Gastric biopsy was taken from 1079 consenting patients. The specimens were processed by PCR to identify H. pylori and to determine the genotypic profile by PCR characterizing vacA s, vacA m and vacA i regions directly from biopsies H. pylori positives. VacA genotyping revealed the predominance of vacA m2 (53.2%), vacA s2 (52.9%) and vacA i2 (52%). The most virulent vacA alleles (s1, i1 and m1) are more predominant in men (47.3%, 41.9% and 46.1% respectively) than in women (38.3%, 33.3% and 37% respectively). However, the association between vacA genotypes and age did not reach a statistical significant value. Logistic regression analysis results show that vacA i1m1 and vacA i1m2 genotypes were strongly associated with the risk of GC, the Odds Ratio (95% confidence interval) was 29.73 [5.08-173.73] and 9.17 [2.06-40.82] respectively, while vacAs1/cagA+ seems to be a risk factor for DU since it is inversely associated with GC (OR was 0.13 [0.02-0.75]. The results of this study suggest that vacA i1 genotype independently to vacAm status may be of a clinical usefulness and will help to identify patients at a high risk of GC development.
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Affiliation(s)
- Mounia El Khadir
- Laboratoire de Microbiologie et de Biologie Moléculaire, Equipe Micro-organismes, Génomique et Facteurs Oncogènes, Faculté de Médecine et de Pharmacie de Fès (FMPF), Université Sidi Mohammed Ben Abdellah (USMBA), Fez, Morocco
- Laboratoire de Biotechnologie, Faculté des Sciences Dhar El Mehraz, USMBA, Fez, Morocco
| | - Samia Alaoui Boukhris
- Laboratoire de Microbiologie et de Biologie Moléculaire, Equipe Micro-organismes, Génomique et Facteurs Oncogènes, Faculté de Médecine et de Pharmacie de Fès (FMPF), Université Sidi Mohammed Ben Abdellah (USMBA), Fez, Morocco
| | - Dafr-Allah Benajah
- Service d’Hépato Gastro-entérologie, CHU Hassan II de Fès, Equipe Maladies de l’Appareil Digestif, FMPF, Fez, Morocco
- Laboratoire de Pathologie Humaine, Biomédecine et Environnement, FMPF, USMBA, Fez, Morocco
| | - Karima El Rhazi
- Laboratoire d’Epidémiologie et de Recherche Clinique, FMPF, USMBA, Fez, Morocco
| | - Sidi Adil Ibrahimi
- Service d’Hépato Gastro-entérologie, CHU Hassan II de Fès, Equipe Maladies de l’Appareil Digestif, FMPF, Fez, Morocco
- Laboratoire de Pathologie Humaine, Biomédecine et Environnement, FMPF, USMBA, Fez, Morocco
| | - Mohamed El Abkari
- Service d’Hépato Gastro-entérologie, CHU Hassan II de Fès, Equipe Maladies de l’Appareil Digestif, FMPF, Fez, Morocco
- Laboratoire de Pathologie Humaine, Biomédecine et Environnement, FMPF, USMBA, Fez, Morocco
| | | | - Chakib Nejjari
- Laboratoire d’Epidémiologie et de Recherche Clinique, FMPF, USMBA, Fez, Morocco
| | | | - Mohamed Benlemlih
- Laboratoire de Biotechnologie, Faculté des Sciences Dhar El Mehraz, USMBA, Fez, Morocco
| | - Bahia Bennani
- Laboratoire de Microbiologie et de Biologie Moléculaire, Equipe Micro-organismes, Génomique et Facteurs Oncogènes, Faculté de Médecine et de Pharmacie de Fès (FMPF), Université Sidi Mohammed Ben Abdellah (USMBA), Fez, Morocco
- Laboratoire de Pathologie Humaine, Biomédecine et Environnement, FMPF, USMBA, Fez, Morocco
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19
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Pyburn TM, Foegeding NJ, González-Rivera C, McDonald NA, Gould KL, Cover TL, Ohi MD. Structural organization of membrane-inserted hexamers formed by Helicobacter pylori VacA toxin. Mol Microbiol 2016; 102:22-36. [PMID: 27309820 PMCID: PMC5035229 DOI: 10.1111/mmi.13443] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2016] [Indexed: 01/08/2023]
Abstract
Helicobacter pylori colonizes the human stomach and is a potential cause of peptic ulceration or gastric adenocarcinoma. H. pylori secretes a pore-forming toxin known as vacuolating cytotoxin A (VacA). The 88 kDa secreted VacA protein, composed of an N-terminal p33 domain and a C-terminal p55 domain, assembles into water-soluble oligomers. The structural organization of membrane-bound VacA has not been characterized in any detail and the role(s) of specific VacA domains in membrane binding and insertion are unclear. We show that membrane-bound VacA organizes into hexameric oligomers. Comparison of the two-dimensional averages of membrane-bound and soluble VacA hexamers generated using single particle electron microscopy reveals a structural difference in the central region of the oligomers (corresponding to the p33 domain), suggesting that membrane association triggers a structural change in the p33 domain. Analyses of the isolated p55 domain and VacA variants demonstrate that while the p55 domain can bind membranes, the p33 domain is required for membrane insertion. Surprisingly, neither VacA oligomerization nor the presence of putative transmembrane GXXXG repeats in the p33 domain is required for membrane insertion. These findings provide new insights into the process by which VacA binds and inserts into the lipid bilayer to form membrane channels.
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Affiliation(s)
- Tasia M Pyburn
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, 37232
| | - Nora J Foegeding
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, 37232
| | - Christian González-Rivera
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, 37232
| | - Nathan A McDonald
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, 37232
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, 37232
| | - Timothy L Cover
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, 37232
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, 37232
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN, 37212
| | - Melanie D Ohi
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, 37232.
- Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN, 37232.
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20
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Bagheri N, Azadegan-Dehkordi F, Rafieian-Kopaei M, Rahimian G, Asadi-Samani M, Shirzad H. Clinical relevance of Helicobacter pylori virulence factors in Iranian patients with gastrointestinal diseases. Microb Pathog 2016; 100:154-162. [PMID: 27666510 DOI: 10.1016/j.micpath.2016.09.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 09/21/2016] [Accepted: 09/21/2016] [Indexed: 12/21/2022]
Abstract
Helicobacter pylori (H. pylori) usually colonizes the gastric mucosa of more than 50% of the human population, causing an infection that may appear in early childhood and can persist for life. H. pylori is suggested as the main cause of peptic ulcer and chronic gastritis. It is also associated with gastric cancer. Its severity and symptoms depend on environmental factors, host susceptibility and bacterial components, which allow H. pylori to switch between commensalism and pathogenicity. H. pylori is genetically highly variable, and the variability which affects H. pylori virulence factors might be useful in identifying the strains with different degrees of pathogenicity. The geographic distribution of distinct H. pylori genotypes is largely unknown and should be established. The prevalence of more pathogenic genotypes in certain areas may have important epidemiological consequences. It also might be associated with the severity of H. pylori related diseases in such regions. Given that Iran is located in the Middle East and Asian populations have revealed high levels of gastric cancer, it is of clinical interest to clarify the potential of H. pylori virulence markers in predicting the associated clinical outcomes. In this review, clinical relevance of adhesion molecules and significant virulence factors of H. pylori in Iranian patients with gastrointestinal diseases are discussed in comparison to other countries.
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Affiliation(s)
- Nader Bagheri
- Cellular and Molecular Research Center, Shahrekord University of Medical Sciences, Shahrekord, Iran; Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | | | | | - Ghorbanali Rahimian
- Department of Internal Medicine, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Majid Asadi-Samani
- Medical Plants Research Center, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Hedaytollah Shirzad
- Cellular and Molecular Research Center, Shahrekord University of Medical Sciences, Shahrekord, Iran.
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21
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Thi Huyen Trang T, Thanh Binh T, Yamaoka Y. Relationship between vacA Types and Development of Gastroduodenal Diseases. Toxins (Basel) 2016; 8:toxins8060182. [PMID: 27294955 PMCID: PMC4926148 DOI: 10.3390/toxins8060182] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 05/29/2016] [Accepted: 05/31/2016] [Indexed: 02/07/2023] Open
Abstract
The Helicobacter pylori vacuolating cytotoxin (VacA) is a secreted pore-forming toxin and a major virulence factor in the pathogenesis of H. pylori infection. While VacA is present in almost all strains, only some forms are toxigenic and pathogenic. While vacA and its genotypes are considered as markers of H. pylori-related diseases or disorders, the pathophysiological mechanisms of VacA and its genotypes remain controversial. This review outlines key findings of publications regarding vacA with emphasis on the relationship between vacA genotypes and the development of human disease.
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Affiliation(s)
- Tran Thi Huyen Trang
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, 1-1 Idaigaoka, Hasama-Machi, Yufu-City, Oita 879-5593, Japan.
- Department of Molecular Biology, 108 Hospital, Hanoi, Vietnam.
| | - Tran Thanh Binh
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, 1-1 Idaigaoka, Hasama-Machi, Yufu-City, Oita 879-5593, Japan.
- Department of Endoscopy, Cho Ray Hospital, Ho Chi Minh, Vietnam.
| | - Yoshio Yamaoka
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, 1-1 Idaigaoka, Hasama-Machi, Yufu-City, Oita 879-5593, Japan.
- Department of Medicine-Gastroenterology, Michael E. DeBakey Veterans Affairs Medical Center and Baylor College of Medicine, Houston, TX 77030, USA.
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22
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Foegeding NJ, Caston RR, McClain MS, Ohi MD, Cover TL. An Overview of Helicobacter pylori VacA Toxin Biology. Toxins (Basel) 2016; 8:toxins8060173. [PMID: 27271669 PMCID: PMC4926140 DOI: 10.3390/toxins8060173] [Citation(s) in RCA: 129] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Revised: 05/18/2016] [Accepted: 05/27/2016] [Indexed: 12/11/2022] Open
Abstract
The VacA toxin secreted by Helicobacter pylori enhances the ability of the bacteria to colonize the stomach and contributes to the pathogenesis of gastric adenocarcinoma and peptic ulcer disease. The amino acid sequence and structure of VacA are unrelated to corresponding features of other known bacterial toxins. VacA is classified as a pore-forming toxin, and many of its effects on host cells are attributed to formation of channels in intracellular sites. The most extensively studied VacA activity is its capacity to stimulate vacuole formation, but the toxin has many additional effects on host cells. Multiple cell types are susceptible to VacA, including gastric epithelial cells, parietal cells, T cells, and other types of immune cells. This review focuses on the wide range of VacA actions that are detectable in vitro, as well as actions of VacA in vivo that are relevant for H. pylori colonization of the stomach and development of gastric disease.
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Affiliation(s)
- Nora J Foegeding
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
| | - Rhonda R Caston
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
| | - Mark S McClain
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
| | - Melanie D Ohi
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA.
| | - Timothy L Cover
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN 37212, USA.
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23
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Sinnett CG, Letley DP, Narayanan GL, Patel SR, Hussein NR, Zaitoun AM, Robinson K, Atherton JC. Helicobacter pylori vacA transcription is genetically-determined and stratifies the level of human gastric inflammation and atrophy. J Clin Pathol 2016; 69:968-973. [PMID: 27189958 PMCID: PMC5136723 DOI: 10.1136/jclinpath-2016-203641] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 04/07/2016] [Indexed: 11/11/2022]
Abstract
Aims Helicobacter pylori infection is the major cause of peptic ulceration and gastric cancer, and an important virulence determinant is its vacuolating cytotoxin vacA. Previously, we have described allelic variation in vacA which determines toxin activity and disease risk. Here we aimed to quantify vacA mRNA expression in the human stomach, define its genetic determinants and assess how well it predicts gastric pathology. Methods Gastric biopsies were donated by 39 patients with H. pylori infection attending for endoscopy at Queen's Medical Centre, Nottingham, UK. Total RNA was extracted, and vacA mRNA quantified by reverse transcriptase quantitative PCR. Separate biopsies were histologically scored for inflammation and atrophy using the updated Sydney system. H. pylori strains were isolated from further biopsies, and the nucleotide sequence upstream of vacA determined. Results vacA mRNA levels in human stomachs varied by two orders of magnitude independently of vacA allelic type. Among vacA i1-type (toxic) strains, increased vacA expression was strongly associated with higher grade gastric inflammation (p<0.02), neutrophil infiltration (p<0.005) and the presence of atrophy (p<0.01). A polymorphism at nucleotide +28 near the base of a potential stem-loop structure within the 5′ untranslated region was significantly associated with vacA transcript level and inflammation. Conclusions Increased gastric vacA expression during H. pylori infection is associated with inflammation and premalignant pathology. The +28 nucleotide within the vacA 5′ stem-loop stratifies disease risk among toxic vacA i1-type strains.
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Affiliation(s)
- Charlotte G Sinnett
- NIHR Biomedical Research Unit in Gastrointestinal and Liver Diseases at Nottingham University Hospitals NHS Trust and the University of Nottingham, School of Medicine, University of Nottingham, Nottingham, UK
| | - Darren P Letley
- NIHR Biomedical Research Unit in Gastrointestinal and Liver Diseases at Nottingham University Hospitals NHS Trust and the University of Nottingham, School of Medicine, University of Nottingham, Nottingham, UK
| | - Geetha L Narayanan
- NIHR Biomedical Research Unit in Gastrointestinal and Liver Diseases at Nottingham University Hospitals NHS Trust and the University of Nottingham, School of Medicine, University of Nottingham, Nottingham, UK
| | - Sapna R Patel
- NIHR Biomedical Research Unit in Gastrointestinal and Liver Diseases at Nottingham University Hospitals NHS Trust and the University of Nottingham, School of Medicine, University of Nottingham, Nottingham, UK
| | - Nawfal R Hussein
- NIHR Biomedical Research Unit in Gastrointestinal and Liver Diseases at Nottingham University Hospitals NHS Trust and the University of Nottingham, School of Medicine, University of Nottingham, Nottingham, UK
| | - Abed M Zaitoun
- Department of Cellular Pathology, Nottingham University Hospitals NHS Trust, Nottingham, UK
| | - Karen Robinson
- NIHR Biomedical Research Unit in Gastrointestinal and Liver Diseases at Nottingham University Hospitals NHS Trust and the University of Nottingham, School of Medicine, University of Nottingham, Nottingham, UK
| | - John C Atherton
- NIHR Biomedical Research Unit in Gastrointestinal and Liver Diseases at Nottingham University Hospitals NHS Trust and the University of Nottingham, School of Medicine, University of Nottingham, Nottingham, UK
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Abstract
Gastric cancer is a leading cause of cancer-related death worldwide. Helicobacter pylori infection is the strongest known risk factor for this malignancy. An important goal is to identify H. pylori-infected persons at high risk for gastric cancer, so that these individuals can be targeted for therapeutic intervention. H. pylori exhibits a high level of intraspecies genetic diversity, and over the past two decades, many studies have endeavored to identify strain-specific features of H. pylori that are linked to development of gastric cancer. One of the most prominent differences among H. pylori strains is the presence or absence of a 40-kb chromosomal region known as the cag pathogenicity island (PAI). Current evidence suggests that the risk of gastric cancer is very low among persons harboring H. pylori strains that lack the cag PAI. Among persons harboring strains that contain the cag PAI, the risk of gastric cancer is shaped by a complex interplay among multiple strain-specific bacterial factors as well as host factors. This review discusses the strain-specific properties of H. pylori that correlate with increased gastric cancer risk, focusing in particular on secreted proteins and surface-exposed proteins, and describes evidence from cell culture and animal models linking these factors to gastric cancer pathogenesis. Strain-specific features of H. pylori that may account for geographic variation in gastric cancer incidence are also discussed.
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25
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Amilon KR, Letley DP, Winter JA, Robinson K, Atherton JC. Expression of the Helicobacter pylori virulence factor vacuolating cytotoxin A (vacA) is influenced by a potential stem-loop structure in the 5' untranslated region of the transcript. Mol Microbiol 2015; 98:831-46. [PMID: 26259667 PMCID: PMC4843948 DOI: 10.1111/mmi.13160] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2015] [Indexed: 01/03/2023]
Abstract
The vacuolating cytotoxin, VacA, is an important virulence factor secreted by the gastric pathogen Helicobacter pylori. Certain vacA genotypes are strongly associated with disease risk, but the association is not absolute. The factors determining vacA gene expression are not fully understood, and the mechanisms of its regulation are elusive. We have identified a potential mRNA stem‐loop forming structure in the 5′ untranslated region (UTR) of the vacA transcript. Using site‐directed mutagenesis, we found that disruption of the stem‐loop structure reduced steady‐state mRNA levels between two‐ and sixfold (P = 0.0005) and decreased mRNA half‐life compared with wild type (P = 0.03). This led to a marked reduction in VacA protein levels and overall toxin activity. Additionally, during stressful environmental conditions of acid pH or high environmental salt concentrations, when general transcription of vacA was decreased or increased respectively, the stabilising effects of the stem‐loop were even more pronounced. Our results suggest that the stem‐loop structure in the vacA 5′ UTR is an important determinant of vacA expression through stabilisation of the vacA mRNA transcript and that the stabilising effect is of particular importance during conditions of environmental stress.
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Affiliation(s)
- Karin R Amilon
- Nottingham Digestive Diseases Biomedical Research Unit, School of Medicine, University of Nottingham, Nottingham, UK
| | - Darren P Letley
- Nottingham Digestive Diseases Biomedical Research Unit, School of Medicine, University of Nottingham, Nottingham, UK
| | - Jody A Winter
- Nottingham Digestive Diseases Biomedical Research Unit, School of Medicine, University of Nottingham, Nottingham, UK
| | - Karen Robinson
- Nottingham Digestive Diseases Biomedical Research Unit, School of Medicine, University of Nottingham, Nottingham, UK
| | - John C Atherton
- Nottingham Digestive Diseases Biomedical Research Unit, School of Medicine, University of Nottingham, Nottingham, UK
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Vannarath S, Vilaichone RK, Rasachak B, Mairiang P, Yamaoka Y, Shiota S, Binh TT, Mahachai V. Virulence genes of Helicobacter pylori in gastritis, peptic ulcer and gastric cancer in Laos. Asian Pac J Cancer Prev 2015; 15:9027-31. [PMID: 25374247 DOI: 10.7314/apjcp.2014.15.20.9027] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Helicobacter pylori (H. pylori) infection is an established cause of peptic ulcers and gastric cancer. The aim of this study was to identify H. pylori genotypes and to examine their associations with geographical regions and gastritis, peptic ulcers and gastric cancer in Laos. MATERIALS AND METHODS A total of 329 Lao dyspeptic patients who underwent gastroscopy at Mahosot Hospital, Vientiane, Laos during December 2010--March 2012 were enrolled. Two biopsy specimens (one each from the antrum and corpus) were obtained for CLO testing and only CLO test-positive gastric tissue were used to extract DNA. PCR and sequencing were identified for variants of the cagA and vacA genotypes. RESULTS Some 119 Laos patients (36.2%) were found to be infected with H. pylori including 83 with gastritis, 13 with gastric ulcers (GU), 20 with duodenal ulcers (DU) and 3 with gastric cancer. cagA was detected in 99.2%. East-Asian-type cagA (62%) and vacA s1c (64.7%) were predominant genotypes in Laos. vacA s1c-m1b was significantly higher in GU than gastritis (53.8% vs. 24.1%; P-value=0.04) whereas vacA s1a-m2 was significantly higher in DU than gastritis (40.0% vs. 16.9%; P-value=0.03). East-Asian-type cagA and vacA s1c were significantly higher in highland than lowland Lao (100% vs. 55.8%; P-value=0.001 and 88.2% vs. 61.5%, P-value=0.03 respectively). CONCLUSIONS H. pylori is a common infection in Laos, as in other countries in Southeast Asia. The cagA gene was demonstrated in nearly all Laos patients, cagA and vacA genotypes being possible important factors in explaining H. pylori infection and disease outcomes in Laos.
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Affiliation(s)
- Sengdao Vannarath
- Department of Gastroenterology, Mahosot Hospital, Vientiane, Laos E-mail :
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Santibáñez M, Aguirre E, Belda S, Aragones N, Saez J, Rodríguez JC, Galiana A, Sola-Vera J, Ruiz-García M, Paz-Zulueta M, Sarabia-Lavín R, Brotons A, López-Girona E, Pérez E, Sillero C, Royo G. Relationship between tobacco, cagA and vacA i1 virulence factors and bacterial load in patients infected by Helicobacter pylori. PLoS One 2015; 10:e0120444. [PMID: 25794002 PMCID: PMC4368826 DOI: 10.1371/journal.pone.0120444] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Accepted: 01/22/2015] [Indexed: 12/19/2022] Open
Abstract
Background and Aim Several biological and epidemiological studies support a relationship between smoking and Helicobacter pylori (H. pylori) to increase the risk of pathology. However, there have been few studies on the potential synergistic association between specific cagA and vacA virulence factors and smoking in patients infected by Helicobacter pylori. We studied the relationship between smoking and cagA, vacA i1 virulence factors and bacterial load in H. pylori infected patients. Methods Biopsies of the gastric corpus and antrum from 155 consecutive patients in whom there was clinical suspicion of infection by H. pylori were processed. In 106 patients H. pylori infection was detected. Molecular methods were used to quantify the number of microorganisms and presence of cagA and vacA i1 genes. A standardized questionnaire was used to obtain patients’ clinical data and lifestyle variables, including tobacco and alcohol consumption. Adjusted Odds Ratios (ORadjusted) were estimated by unconditional logistic regression. Results cagA was significantly associated with active-smoking at endoscope: ORadjusted 4.52. Evidence of association was found for vacA i1 (ORadjusted 3.15). Bacterial load was higher in active-smokers, although these differences did not yield statistical significance (median of 262.2 versus 79.4 copies of H. pylori per cell). Conclusions The association between smoking and a higher risk of being infected by a virulent bacterial population and with higher bacterial load, support a complex interaction between H. pylori infection and environmental factors.
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Affiliation(s)
- Miguel Santibáñez
- Departamento de Salud Pública, Universidad de Cantabria, Santander, Spain
- IDIVAL-Instituto de Investigación Marqués de Valdecilla, Santander, Spain
- * E-mail:
| | - Estefanía Aguirre
- Microbiology S. Elche University General Hospital, Elche (Alicante), Spain
| | - Sofía Belda
- Microbiology S. Elche University General Hospital, Elche (Alicante), Spain
| | - Nuria Aragones
- CIBER in Epidemiology and Public Health (CIBERESP), Madrid, Spain
- Environmental and Cancer Epidemiology Unit, National Center of Epidemiology, ISCIII, Madrid, Spain
| | - Jesús Saez
- Digestive Medicine S. Elche University General Hospital, Elche (Alicante), Spain
| | - Juan Carlos Rodríguez
- Microbiology S. Alicante University General Hospital, Alicante, Spain
- Miguel Hernández University, Elche, Spain
| | - Antonio Galiana
- Microbiology S. Elche University General Hospital, Elche (Alicante), Spain
| | - Javier Sola-Vera
- Digestive Medicine S. Elche University General Hospital, Elche (Alicante), Spain
| | | | - María Paz-Zulueta
- Departamento de Enfermería, Universidad de Cantabria, Santander, Spain
| | | | - Alicia Brotons
- Digestive Medicine S. Elche University General Hospital, Elche (Alicante), Spain
| | - Elena López-Girona
- Microbiology S. Elche University General Hospital, Elche (Alicante), Spain
| | - Estefanía Pérez
- Digestive Medicine S. Elche University General Hospital, Elche (Alicante), Spain
| | - Carlos Sillero
- Digestive Medicine S. Elche University General Hospital, Elche (Alicante), Spain
| | - Gloria Royo
- Microbiology S. Elche University General Hospital, Elche (Alicante), Spain
- Miguel Hernández University, Elche, Spain
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Alsaimary AE, Abdulnbi HM, Laibi A, Jwad AR. The occurrence of Helicobacter pylori in hydatid liver disease. Asian Pac J Trop Biomed 2015; 2:233-4. [PMID: 23569904 DOI: 10.1016/s2221-1691(12)60048-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Revised: 09/05/2011] [Accepted: 09/27/2011] [Indexed: 01/06/2023] Open
Abstract
OBJECTIVE To detect the prevalence of Helicobacter pylori (H. pylori) in hydatid liver disease. METHODS A total of 58 patients with hydatid liver disease attending AL-Sadder Teaching Hospital in Al-Najaf and Al-Basrah governorate from February to August, 2008 were included in the study and served as group A. One hundred and twenty 1st degree relative patients (group B) and 20 normal persons including 10 male and 10 female (group C) as control were detected for the presence of H. pylori infection in general population. Chest X-ray was done for the above groups to exclude lung hydrated cyst. The patients were screened by ultrasound to obtain intra abdominal hydrated cyst and enzyme-linked immuno sorbent assay (ELISA) test was utilized to detect the H. pylori infection. RESULTS Fifty eight patients from group A with hydatid liver disease, 30 male (51.7%) and 28 female (48.3%) were screened for the presence of H. pylori infection by using ELISA test. We found that 28 patients from group A had positive ELISA test including 19 male (32.8%) and 9 female (15.5%) (P<0.01). However, there were no positive results of H. pylori infection in group B and C by chest X-ray, ultrasound and ELISA test. CONCLUSIONS It can be concluded that there is a strong relationship between hydatid liver disease and presence of H. pylori.
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Halder P, Datta C, Kumar R, Sharma AK, Basu J, Kundu M. The secreted antigen, HP0175, of Helicobacter pylori links the unfolded protein response (UPR) to autophagy in gastric epithelial cells. Cell Microbiol 2015; 17:714-29. [PMID: 25439545 DOI: 10.1111/cmi.12396] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2014] [Revised: 11/11/2014] [Accepted: 11/15/2014] [Indexed: 12/13/2022]
Abstract
Autophagy is an intracellular catabolic process that is required to maintain cellular homeostasis. Pathogen-elicited host cell autophagy may favour containment of infection or may help in bacterial survival. Pathogens have developed the ability to modulate host autophagy. The secreted antigen HP0175, a peptidyl prolyl cis,trans isomerase of Helicobacter pylori, has moonlighting functions with reference to host cells. Here we show that it executes autophagy in gastric epithelial cells. Autophagy is dependent on the unfolded protein response (UPR) that activates the expression of PKR-like ER kinase (PERK). This is accompanied by phosphorylation of eukaryotic initiation factor 2α (eIF-2α) and transcriptional activation of ATF4 and CHOP. Knockdown of UPR-related genes inhibits the conversion of LC3I to LC3II, a marker of autophagy. The autophagy-inducing ability of H. pylori is compromised when cells are infected with an isogenic hp0175 mutant. Autophagy precedes apoptosis. Silencing of BECLIN1 augments cleavage of caspase 3 as well as apoptosis. Increased apoptosis of gastric epithelial cells is known to be linked to H. pylori-mediated gastric inflammation and carcinogenesis. To the best of our knowledge, this study provides the first demonstration of how HP0175 endowed with moonlighting functions links UPR-dependent autophagy and apoptosis during H. pylori infection.
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30
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Ferreira RM, Machado JC, Figueiredo C. Clinical relevance of Helicobacter pylori vacA and cagA genotypes in gastric carcinoma. Best Pract Res Clin Gastroenterol 2014; 28:1003-15. [PMID: 25439067 DOI: 10.1016/j.bpg.2014.09.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 08/21/2014] [Accepted: 09/15/2014] [Indexed: 02/08/2023]
Abstract
Helicobacter pylori infection is the major etiological factor of gastric carcinoma. This disease is the result of a long, multistep, and multifactorial process, which occurs only in a small proportion of patients infected with H. pylori. Gastric carcinoma development is influenced by host genetic susceptibility factors, environmental factors, and H. pylori virulence. H. pylori is genetically highly variable, and variability that affects H. pylori virulence factors may be useful to identify strains with different degrees of pathogenicity. This review will focus on VacA and CagA that have polymorphic regions that impact their functional properties. The characterization of H. pylori vacA and cagA-associated could be useful for identifying patients at highest risk of disease, who could be offered H. pylori eradication therapy and who could be included in programs of more intensive surveillance in an attempt to reduce gastric carcinoma incidence.
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Affiliation(s)
- Rui M Ferreira
- Ipatimup - Institute of Molecular Pathology and Immunology of the University of Porto, Portugal
| | - José C Machado
- Ipatimup - Institute of Molecular Pathology and Immunology of the University of Porto, Portugal; Department of Pathology and Oncology, Faculty of Medicine of the University of Porto, Porto, Portugal
| | - Ceu Figueiredo
- Ipatimup - Institute of Molecular Pathology and Immunology of the University of Porto, Portugal; Department of Pathology and Oncology, Faculty of Medicine of the University of Porto, Porto, Portugal.
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31
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Vacuolating cytotoxin genotypes are strong markers of gastric cancer and duodenal ulcer-associated Helicobacter pylori strains: a matched case-control study. J Clin Microbiol 2014; 52:2984-9. [PMID: 24920772 DOI: 10.1128/jcm.00551-14] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The Helicobacter pylori virulence gene, cagA, and active forms of the vacuolating cytotoxin gene, vacA, are major determinants of pathogenesis. However, previous studies linking these factors to disease risk have often included patients using aspirin/nonsteroidal anti-inflammatory agents (NSAIDs) or acid-suppressing drugs, both of which may confound results. Also, particularly for gastric cancer (GC), controls have often been of quite different ages. Here, we performed a careful study in a "clean" Belgian population with gastric cancer cases age and sex matched to 4 controls and with a parallel duodenal ulcer (DU) group. As in other populations, there was a close association between the presence of cagA and the vacA s1 genotype. For GC, associations were found for vacA s1-positive (P = 0.01, odds ratio [OR], 9.37; 95% confidence interval [CI], 1.16 to 201.89), i1-positive (P = 0.003; OR, 12.08; 95% CI, 1.50 to 259.64), and cagA-positive status (P < 0.05; OR, infinity; 95% CI, 0.76 to infinity). For DU, associations were found with vacA s1 (P = 0.002; OR, 6.04; 95% CI, 1.52 to 27.87) and i1 (P = 0.004; OR, 4.35; 95% CI, 1.36 to 14.78) status but not with cagA status. Neither condition showed independent associations with the vacA m1 allele or with more biologically active forms of cagA with longer 3' variable regions. In this Belgian population, the best markers of gastric cancer- and duodenal ulcer-associated strains are the vacA s1 and i1 genotypes. This fits with experimental data showing that the s and i regions are the key determinants of vacuolating cytotoxin activity.
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Roesler BM, Rabelo-Gonçalves EMA, Zeitune JMR. Virulence Factors of Helicobacter pylori: A Review. CLINICAL MEDICINE INSIGHTS. GASTROENTEROLOGY 2014; 7:9-17. [PMID: 24833944 PMCID: PMC4019226 DOI: 10.4137/cgast.s13760] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Revised: 02/16/2014] [Accepted: 02/17/2014] [Indexed: 12/20/2022]
Abstract
Helicobacter pylori is a spiral-shaped Gram-negative bacterium that colonizes the human stomach and can establish a long-term infection of the gastric mucosa, a condition that affects the relative risk of developing various clinical disorders of the upper gastrointestinal tract, such as chronic gastritis, peptic ulcer disease, mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric adenocarcinoma. H. pylori presents a high-level of genetic diversity, which can be an important factor in its adaptation to the host stomach and also for the clinical outcome of infection. There are important H. pylori virulence factors that, along with host characteristics and the external environment, have been associated with the different occurrences of diseases. This review is aimed to analyzing and summarizing the main of them and possible associations with the clinical outcome.
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Affiliation(s)
- Bruna M Roesler
- Department of Internal Medicine, Faculty of Medical Sciences, State University of Campinas, Campinas, São Paulo, Brazil. ; Center of Diagnosis of Digestive Diseases, Faculty of Medical Sciences, State University of Campinas, Campinas, São Paulo, Brazil
| | - Elizabeth M A Rabelo-Gonçalves
- Department of Internal Medicine, Faculty of Medical Sciences, State University of Campinas, Campinas, São Paulo, Brazil. ; Center of Diagnosis of Digestive Diseases, Faculty of Medical Sciences, State University of Campinas, Campinas, São Paulo, Brazil
| | - José M R Zeitune
- Department of Internal Medicine, Faculty of Medical Sciences, State University of Campinas, Campinas, São Paulo, Brazil. ; Center of Diagnosis of Digestive Diseases, Faculty of Medical Sciences, State University of Campinas, Campinas, São Paulo, Brazil
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Winter JA, Letley DP, Cook KW, Rhead JL, Zaitoun AAM, Ingram RJM, Amilon KR, Croxall NJ, Kaye PV, Robinson K, Atherton JC. A role for the vacuolating cytotoxin, VacA, in colonization and Helicobacter pylori-induced metaplasia in the stomach. J Infect Dis 2014; 210:954-63. [PMID: 24625807 PMCID: PMC4136800 DOI: 10.1093/infdis/jiu154] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Carriage of Helicobacter pylori strains producing more active (s1/i1) forms of VacA is strongly associated with gastric adenocarcinoma. To our knowledge, we are the first to determine effects of different polymorphic forms of VacA on inflammation and metaplasia in the mouse stomach. Bacteria producing the less active s2/i2 form of VacA colonized mice more efficiently than mutants null for VacA or producing more active forms of it, providing the first evidence of a positive role for the minimally active s2/i2 toxin. Strains producing more active toxin forms induced more severe and extensive metaplasia and inflammation in the mouse stomach than strains producing weakly active (s2/i2) toxin. We also examined the association in humans, controlling for cagPAI status. In human gastric biopsy specimens, the vacA i1 allele was strongly associated with precancerous intestinal metaplasia, with almost complete absence of intestinal metaplasia in subjects infected with i2-type strains, even in a vacA s1, cagA+ background.
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Affiliation(s)
- Jody A Winter
- Nottingham Digestive Diseases Biomedical Research Unit, School of Medicine, University of Nottingham
| | - Darren P Letley
- Nottingham Digestive Diseases Biomedical Research Unit, School of Medicine, University of Nottingham
| | - Katherine W Cook
- Nottingham Digestive Diseases Biomedical Research Unit, School of Medicine, University of Nottingham
| | - Joanne L Rhead
- Nottingham Digestive Diseases Biomedical Research Unit, School of Medicine, University of Nottingham
| | - Abed A M Zaitoun
- Department of Pathology, Nottingham University Hospitals NHS Trust, Queen's Medical Centre Campus, United Kingdom
| | - Richard J M Ingram
- Nottingham Digestive Diseases Biomedical Research Unit, School of Medicine, University of Nottingham
| | - Karin R Amilon
- Nottingham Digestive Diseases Biomedical Research Unit, School of Medicine, University of Nottingham
| | - Nicola J Croxall
- Nottingham Digestive Diseases Biomedical Research Unit, School of Medicine, University of Nottingham
| | - Phillip V Kaye
- Department of Pathology, Nottingham University Hospitals NHS Trust, Queen's Medical Centre Campus, United Kingdom
| | - Karen Robinson
- Nottingham Digestive Diseases Biomedical Research Unit, School of Medicine, University of Nottingham
| | - John C Atherton
- Nottingham Digestive Diseases Biomedical Research Unit, School of Medicine, University of Nottingham
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Helicobacter pylori membrane vesicles stimulate innate pro- and anti-inflammatory responses and induce apoptosis in Jurkat T cells. Infect Immun 2014; 82:1372-81. [PMID: 24421041 DOI: 10.1128/iai.01443-13] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Persistent Helicobacter pylori infection induces chronic inflammation in the human gastric mucosa, which is associated with development of peptic ulceration, gastric atrophy, and gastric adenocarcinoma. It has been postulated that secretion of immunomodulatory molecules by H. pylori facilitates bacterial persistence, and membrane vesicles (MV), which have the potential to cross the gastric epithelial barrier, may mediate delivery of these molecules to host immune cells. However, bacterial MV effects on human immune cells remain largely uncharacterized to date. In the present study, we investigated the immunomodulatory effects of H. pylori MV with and without the vacuolating cytotoxin, VacA, which inhibits human T cell activity. We show a high degree of variability in the toxin content of vesicles between two H. pylori strains (SS1 and 60190). Vesicles from the more toxigenic 60190 strain contain more VacA (s1i1 type) than vesicles from the SS1 strain (s2i2 VacA), but engineering the SS1 strain to produce s1i1 VacA did not increase the toxin content of its vesicles. Vesicles from all strains tested, including a 60190 isogenic mutant null for VacA, strongly induced interleukin-10 (IL-10) and IL-6 production by human peripheral blood mononuclear cells independently of the infection status of the donor. Finally, we show that H. pylori MV induce T cell apoptosis and that this is enhanced by, but not completely dependent on, the carriage of VacA. Together, these findings suggest a role for H. pylori MV in the stimulation of innate pro- and anti-inflammatory responses and in the suppression of T cell immunity.
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Helicobacter pylori VacA suppresses Lactobacillus acidophilus-induced interferon beta signaling in macrophages via alterations in the endocytic pathway. mBio 2013; 4:e00609-12. [PMID: 23760466 PMCID: PMC3685213 DOI: 10.1128/mbio.00609-12] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Helicobacter pylori causes chronic gastritis and avoids elimination by the immune system of the infected host. The commensal bacterium Lactobacillus acidophilus has been suggested to exert beneficial effects as a supplement during H. pylori eradication therapy. In the present study, we applied whole-genome microarray analysis to compare the immune responses induced in murine bone marrow-derived macrophages (BMDMs) stimulated with L. acidophilus, H. pylori, or both bacteria in combination. While L. acidophilus induced a Th1-polarizing response characterized by high expression of interferon beta (IFN-β) and interleukin 12 (IL-12), H. pylori strongly induced the innate cytokines IL-1β and IL-1α. In BMDMs prestimulated with L. acidophilus, H. pylori blocked the expression of L. acidophilus-induced IFN-β and IL-12 and suppressed the expression of key regulators of the Rho, Rac, and Cdc42 GTPases. The inhibition of L. acidophilus-induced IFN-β was independent of H. pylori viability and the virulence factor CagPAI; however, a vacuolating cytotoxin (vacA) mutant was unable to block IFN-β. Confocal microscopy demonstrated that the addition of H. pylori to L. acidophilus-stimulated BMDMs redirects intracellular processing, leading to an accumulation of L. acidophilus in the endosomal and lysosomal compartments. Thus, our findings indicate that H. pylori inhibits the development of a strong Th1-polarizing response in BMDMs stimulated with L. acidophilus by blocking the production of IFN-β in a VacA-dependent manner. We suggest that this abrogation is caused by a redirection of the endocytotic pathway in the processing of L. acidophilus. Approximately half of the world’s population is infected with Helicobacter pylori. The factors that allow this pathogen to persist in the stomach and cause chronic infections have not yet been fully elucidated. In particular, how H. pylori avoids killing by macrophages, one of the main types of immune cell underlying the epithelium, remains elusive. Here we have shown that the H. pylori virulence factor VacA plays a key role by blocking the activation of innate cytokines induced by the probiotic Lactobacillus acidophilus in macrophages and suppresses the expression of key regulators required for the organization and dynamics of the intracellular cytoskeleton. Our results identify potential targets for the treatment of H. pylori infection and vaccination, since specific inhibition of the toxin VacA possibly allows the activation of an efficient immune response and thereby eradication of H. pylori in the host.
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Detection and Genotyping of Helicobacter pylori Gene vacA in Children with Gastroduodenal Diseases and in Adults with Gastric Cancer in Vladivostok. Bull Exp Biol Med 2013; 155:85-8. [DOI: 10.1007/s10517-013-2086-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Abstract
Half of the world's population is infected with Helicobacter pylori and approximately 20% of infected individuals develop overt clinical disease such as ulcers and stomach cancer. Paradoxically, despite its classification as a class I carcinogen, H. pylori has been shown to be protective against development of asthma, allergy, and esophageal disease. Given these conflicting roles for H. pylori, researchers are attempting to define the environmental, host, and pathogen interactions that ultimately result in severe disease in some individuals. From the bacterial perspective, the toxins, CagA and VacA, have each been shown to be polymorphic and to contribute to disease in an allele-dependent manner. Based on the notable advances that have recently been made in the CagA field, herein we review recent studies that have begun to shed light on the role of CagA polymorphism in H. pylori disease. Moreover, we discuss the potential interaction of CagA and VacA as a mediator of gastric disease.
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Ghotaslou R, Milani M, Akhi MT, Nahaei MR, Hasani A, Hejazi MS, Meshkini M. Diversity of Helicobacter Pylori cagA and vacA Genes and Its Relationship with Clinical Outcomes in Azerbaijan, Iran. Adv Pharm Bull 2013; 3:57-62. [PMID: 24312813 DOI: 10.5681/apb.2013.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 10/07/2012] [Accepted: 10/07/2012] [Indexed: 12/11/2022] Open
Abstract
PURPOSE The purpose of this research was to analyze cagA and vacA genotypes status in H. pylori isolates and relationship with clinical outcomes. METHODS Gastric biopsy specimens were cultured for H. pylori isolation and cagA and vacA genes were detected in these isolates. Data were collected and the results were analyzed using χ2 and Fishers exact tests by SPSS software version. 16. RESULTS Of the total 115 H. pylori isolates, 79 (68.7 %) were cagA positive and 82 (71.3%) of isolates contained the s1 allele which 33 (28.7%) were subtype s2. s1m2 was the most frequent vacA allelic combination in the H. pylori isolates examined (63 cases), followed by s2m2 (31 cases), s1m1 (19 cases) and s2m1 (2 case). Strains cagA positive were more frequent in peptic ulcer diseases patients than non ulcer diseases patients, as 47 (59.5%) and 32 (40.5%), while cagA negative were low, as 15 (41.7%) and 21 (58.3%), respectively. CONCLUSION We found that the cagA and vacA status were not related to clinical outcomes in this area. Overall, in the present study, vacA s1/m2, cagA-positive strains were predominant irrespective of clinical outcome, but s2/m1 was rare.
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Affiliation(s)
- Reza Ghotaslou
- Liver and Gastroenterology Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran. ; Department of Microbiology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
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Chambers MG, Pyburn TM, González-Rivera C, Collier SE, Eli I, Yip CK, Takizawa Y, Lacy DB, Cover TL, Ohi MD. Structural analysis of the oligomeric states of Helicobacter pylori VacA toxin. J Mol Biol 2012. [PMID: 23178866 DOI: 10.1016/j.jmb.2012.11.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Helicobacter pylori is a Gram-negative bacterium that colonizes the human stomach and contributes to peptic ulceration and gastric adenocarcinoma. H. pylori secretes a pore-forming exotoxin known as vacuolating toxin (VacA). VacA contains two distinct domains, designated p33 and p55, and assembles into large "snowflake"-shaped oligomers. Thus far, no structural data are available for the p33 domain, which is essential for membrane channel formation. Using single-particle electron microscopy and the random conical tilt approach, we have determined the three-dimensional structures of six VacA oligomeric conformations at ~15-Å resolution. The p55 domain, composed primarily of β-helical structures, localizes to the peripheral arms, while the p33 domain consists of two globular densities that localize within the center of the complexes. By fitting the VacA p55 crystal structure into the electron microscopy densities, we have mapped inter-VacA interactions that support oligomerization. In addition, we have examined VacA variants/mutants that differ from wild-type (WT) VacA in toxin activity and/or oligomeric structural features. Oligomers formed by VacA∆6-27, a mutant that fails to form membrane channels, lack an organized p33 central core. Mixed oligomers containing both WT and VacA∆6-27 subunits also lack an organized core. Oligomers formed by a VacA s2m1 chimera (which lacks cell-vacuolating activity) and VacAΔ301-328 (which retains vacuolating activity) each contain p33 central cores similar to those of WT oligomers. By providing the most detailed view of the VacA structure to date, these data offer new insights into the toxin's channel-forming component and the intermolecular interactions that underlie oligomeric assembly.
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Affiliation(s)
- Melissa G Chambers
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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A novel method for genotyping the Helicobacter pylori vacA intermediate region directly in gastric biopsy specimens. J Clin Microbiol 2012; 50:3983-9. [PMID: 23035185 DOI: 10.1128/jcm.02087-12] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The present report describes a novel method for genotyping the virulence-associated vacA intermediate (i) region of Helicobacter pylori in archive material. vacA i-region genotypes as determined by the novel method were completely concordant with those of sequence analysis and with those of functional vacuolation activity. The method was further validated directly in gastric biopsy specimens of 386 H. pylori-positive cases, and effective characterization of the vacA i region was obtained in 191 of 192 (99.5%) frozen and in 186 of 194 (95.9%) formalin-fixed paraffin-embedded gastric biopsy specimens, respectively. The genotyping method was next used to address the relationship between the vacA genotypes and the cagA status. The vacA i1 genotype was associated with vacA s1 (where s indicates signal region), vacA m1 (where m indicates middle region), and cagA-positive genotypes (P < 0.0001), while the vacA i2 genotype was closely related with vacA s2, vacA m2, and cagA-negative genotypes (P < 0.0001). The relationship between H. pylori vacA i-region genotypes and gastric disease development was subsequently evaluated in the Portuguese population. Patients infected with vacA i1 strains showed an increased risk for gastric atrophy and for gastric carcinoma, with odds ratios of 8.0 (95% confidence interval [CI], 2.3 to 27) and of 22 (95% CI, 7.9 to 63), respectively. Taken together, the results show that this novel H. pylori vacA i-region genotyping method can be applied directly to archive material, providing a fast evaluation of strain virulence determinants without the need of culture. The results further emphasize that the characterization of the vacA i region may be useful to identify patients at higher risk of gastric carcinoma development.
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Alsaimary I, Al-Sadoon M, Jassim A, Hamadi S. Clinical findings and prevalence of helicobacter pylori in patients with gastritis B in Al-basrah governorate. Oman Med J 2012; 24:208-11. [PMID: 22224187 DOI: 10.5001/omj.2009.41] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Accepted: 04/22/2009] [Indexed: 01/26/2023] Open
Abstract
OBJECTIVES To detect the prevalence of H. pylori in patients with gastritis B. METHODS This study involved 58 patients (group A) with gastritis B attending the Al-Sadder teaching hospital from January to November 2008. 120 of family's patients (group B) and normal 20 people, 10 males 10 females (group C) were taken as controls for presence of H. pylori infection in general population. Endoscopy was carried for all patients to diagnose gastritis B. Urease, ELISA test, and culturing on Columbia agar used to detect the presence of H. pylori in these patients RESULTS Fifty-eight patients; 30 males (51.7%) and 28 females (48.3%) were infected with gastritis B. The results showed that 81% of the patients gave positive results of serum IgG anti body. CONCLUSION The results showed that for screening and determining the clinical features of gastritis B, at least two methods for H. pylori are required to give positive result at the same time for the same patient, in order to identify an infected patient with from H. pylori.
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González-Rivera C, Algood HMS, Radin JN, McClain MS, Cover TL. The intermediate region of Helicobacter pylori VacA is a determinant of toxin potency in a Jurkat T cell assay. Infect Immun 2012; 80:2578-88. [PMID: 22585965 PMCID: PMC3434591 DOI: 10.1128/iai.00052-12] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 05/04/2012] [Indexed: 02/08/2023] Open
Abstract
Colonization of the human stomach with Helicobacter pylori is a risk factor for peptic ulceration, noncardia gastric adenocarcinoma, and gastric lymphoma. The secreted VacA toxin is an important H. pylori virulence factor that causes multiple alterations in gastric epithelial cells and T cells. Several families of vacA alleles have been described, and H. pylori strains containing certain vacA types (s1, i1, and m1) are associated with an increased risk of gastric disease, compared to strains containing other vacA types (s2, i2, and m2). Thus far, there has been relatively little study of the role of the VacA intermediate region (i-region) in toxin activity. In this study, we compared the ability of i1 and i2 forms of VacA to cause functional alterations in Jurkat cells. To do this, we manipulated the chromosomal vacA gene in two H. pylori strains to introduce alterations in the region encoding the VacA i-region. We did not detect any differences in the capacity of i1 and i2 forms of VacA to cause vacuolation of RK13 cells. In comparison to i1 forms of VacA, i2 forms of VacA had a diminished capacity to inhibit the activation of nuclear factor of activated T cells (NFAT) and suppress interleukin-2 (IL-2) production. Correspondingly, i2 forms of VacA bound to Jurkat cells less avidly than did i1 forms of VacA. These results indicate that the VacA i-region is an important determinant of VacA effects on human T cell function.
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Affiliation(s)
| | - Holly M. Scott Algood
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Jana N. Radin
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Mark S. McClain
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Timothy L. Cover
- Department of Pathology, Microbiology and Immunology
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, USA
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Kim IJ, Blanke SR. Remodeling the host environment: modulation of the gastric epithelium by the Helicobacter pylori vacuolating toxin (VacA). Front Cell Infect Microbiol 2012; 2:37. [PMID: 22919629 PMCID: PMC3417592 DOI: 10.3389/fcimb.2012.00037] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 03/05/2012] [Indexed: 12/13/2022] Open
Abstract
Virulence mechanisms underlying Helicobacter pylori persistence and disease remain poorly understood, in part, because the factors underlying disease risk are multifactorial and complex. Among the bacterial factors that contribute to the cumulative pathophysiology associated with H. pylori infections, the vacuolating cytotoxin (VacA) is one of the most important. Analogous to a number of H. pylori genes, the vacA gene exhibits allelic mosaicism, and human epidemiological studies have revealed that several families of toxin alleles are predictive of more severe disease. Animal model studies suggest that VacA may contribute to pathogenesis in several ways. VacA functions as an intracellular-acting protein exotoxin. However, VacA does not fit the current prototype of AB intracellular-acting bacterial toxins, which elaborate modulatory effects through the action of an enzymatic domain translocated inside host cells. Rather, VacA may represent an alternative prototype for AB intracellular acting toxins that modulate cellular homeostasis by forming ion-conducting intracellular membrane channels. Although VacA seems to form channels in several different membranes, one of the most important target sites is the mitochondrial inner membrane. VacA apparently take advantage of an unusual intracellular trafficking pathway to mitochondria, where the toxin is imported and depolarizes the inner membrane to disrupt mitochondrial dynamics and cellular energy homeostasis as a mechanism for engaging the apoptotic machinery within host cells. VacA remodeling of the gastric environment appears to be fine-tuned through the action of the Type IV effector protein CagA which, in part, limits the cytotoxic effects of VacA in cells colonized by H. pylori.
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Affiliation(s)
- Ik-Jung Kim
- Department of Microbiology, Institute for Genomic Biology, University of Illinois, Urbana IL, USA
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Prevalence of Helicobacter pylori genotypes (vacA, cagA, cagE and virB11) in gastric cancer in Brazilian's patients: an association with histopathological parameters. Cancer Epidemiol 2011; 35:e32-7. [PMID: 21470935 DOI: 10.1016/j.canep.2011.02.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Revised: 02/15/2011] [Accepted: 02/23/2011] [Indexed: 12/11/2022]
Abstract
PURPOSE To investigate the frequency and the association of vacA alleles, cagA, cagE and virB11 genes of Helicobacter pylori from patients with gastric cancer, considering the clinic histopathological parameters. METHODS One hundred and one gastric adenocarcinoma tissues were assessed by PCR to detect H. pylori and vacA alleles, cagA, cagE and virB11. RESULTS The distribution of cases according to the presence of the genes studied showed that the group containing vacA s1m1, cagA, cagE and virB11 H. pylori genes was significantly more frequent, followed by the group with at least one marker on the right side and left of the island. They were also present in the early stages and were the most frequent in nearly all histopathological grades. CONCLUSIONS This study verified that vacAs1m1 and cag-PAI genes, cagA, cagE and virB11 are important H. pylori markers for gastric cancer development. Also, this study corroborates the importance of cagE and cagA together as cag-PAI marker.
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Swanston T, Haakensen M, Deneer H, Walker EG. The characterization of Helicobacter pylori DNA associated with ancient human remains recovered from a Canadian glacier. PLoS One 2011; 6:e16864. [PMID: 21359221 PMCID: PMC3040200 DOI: 10.1371/journal.pone.0016864] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Accepted: 01/13/2011] [Indexed: 12/14/2022] Open
Abstract
Helicobacter pylori is a gram-negative bacterium that colonizes the stomach of nearly half of the world's population. Genotypic characterization of H. pylori strains involves the analysis of virulence-associated genes, such as vacA, which has multiple alleles. Previous phylogenetic analyses have revealed a connection between modern H. pylori strains and the movement of ancient human populations. In this study, H. pylori DNA was amplified from the stomach tissue of the Kwäday Dän Ts'ìnchi individual. This ancient individual was recovered from the Samuel Glacier in Tatshenshini-Alsek Park, British Columbia, Canada on the traditional territory of the Champagne and Aishihik First Nations and radiocarbon dated to a timeframe of approximately AD 1670 to 1850. This is the first ancient H. pylori strain to be characterized with vacA sequence data. The Tatshenshini H. pylori strain has a potential hybrid vacA m2a/m1d middle (m) region allele and a vacA s2 signal (s) region allele. A vacA s2 allele is more commonly identified with Western strains, and this suggests that European strains were present in northwestern Canada during the ancient individual's time. Phylogenetic analysis indicated that the vacA m1d region of the ancient strain clusters with previously published novel Native American strains that are closely related to Asian strains. This indicates a past connection between the Kwäday Dän Ts'ìnchi individual and the ancestors who arrived in the New World thousands of years ago.
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Affiliation(s)
- Treena Swanston
- Department of Archaeology and Anthropology, University of Saskatchewan, Saskatoon, Canada.
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Jones KR, Whitmire JM, Merrell DS. A Tale of Two Toxins: Helicobacter Pylori CagA and VacA Modulate Host Pathways that Impact Disease. Front Microbiol 2010; 1:115. [PMID: 21687723 PMCID: PMC3109773 DOI: 10.3389/fmicb.2010.00115] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Accepted: 09/27/2010] [Indexed: 12/16/2022] Open
Abstract
Helicobacter pylori is a pathogenic bacterium that colonizes more than 50% of the world's population, which leads to a tremendous medical burden. H. pylori infection is associated with such varied diseases as gastritis, peptic ulcers, and two forms of gastric cancer: gastric adenocarcinoma and mucosa-associated lymphoid tissue lymphoma. This association represents a novel paradigm for cancer development; H. pylori is currently the only bacterium to be recognized as a carcinogen. Therefore, a significant amount of research has been conducted to identify the bacterial factors and the deregulated host cell pathways that are responsible for the progression to more severe disease states. Two of the virulence factors that have been implicated in this process are cytotoxin-associated gene A (CagA) and vacuolating cytotoxin A (VacA), which are cytotoxins that are injected and secreted by H. pylori, respectively. Both of these virulence factors are polymorphic and affect a multitude of host cellular pathways. These combined facts could easily contribute to differences in disease severity across the population as various CagA and VacA alleles differentially target some pathways. Herein we highlight the diverse types of cellular pathways and processes targeted by these important toxins.
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Affiliation(s)
- Kathleen R Jones
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences Bethesda, MD, USA
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Polymorphisms in the intermediate region of VacA impact Helicobacter pylori-induced disease development. J Clin Microbiol 2010; 49:101-10. [PMID: 21084502 DOI: 10.1128/jcm.01782-10] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Helicobacter pylori is the etiological agent of diseases such as gastritis, gastric and duodenal ulcers, and two types of gastric cancers. While some insight has been gained into the etiology of these diverse manifestations, by and large, the reason that some individuals develop more severe disease remains elusive. Recent studies have focused on the roles of H. pylori toxins CagA and VacA on the disease process and have suggested that both toxins are intimately involved. Moreover, CagA and VacA are polymorphic within different H. pylori strains, and particular polymorphisms seem to show a correlation with the development of particular disease states. Among VacA polymorphisms, the intermediate region has recently been proposed to play a major role in disease outcome. In this article, we describe a detailed sequence analysis of the polymorphic intermediate region of vacA from strains obtained from a large South Korean population. We show that polymorphisms found at amino acid position 196 are associated with more severe disease manifestations. Additionally, polymorphisms found at amino acid position 231 are linked to disease in strains that carry the non-EPIYA-ABD allele of CagA. Collectively, these data help explain the impact of the VacA intermediate region on disease and lead to the hypothesis that there are allele-driven interactions between VacA and CagA.
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In Helicobacter pylori auto-inducer-2, but not LuxS/MccAB catalysed reverse transsulphuration, regulates motility through modulation of flagellar gene transcription. BMC Microbiol 2010; 10:210. [PMID: 20691071 PMCID: PMC2923134 DOI: 10.1186/1471-2180-10-210] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Accepted: 08/06/2010] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND LuxS may function as a metabolic enzyme or as the synthase of a quorum sensing signalling molecule, auto-inducer-2 (AI-2); hence, the mechanism underlying phenotypic changes upon luxS inactivation is not always clear. In Helicobacter pylori, we have recently shown that, rather than functioning in recycling methionine as in most bacteria, LuxS (along with newly-characterised MccA and MccB), synthesises cysteine via reverse transsulphuration. In this study, we investigated whether and how LuxS controls motility of H. pylori, specifically if it has its effects via luxS-required cysteine metabolism or via AI-2 synthesis only. RESULTS We report that disruption of luxS renders H. pylori non-motile in soft agar and by microscopy, whereas disruption of mccAHp or mccBHp (other genes in the cysteine provision pathway) does not, implying that the lost phenotype is not due to disrupted cysteine provision. The motility defect of the DeltaluxSHp mutant was complemented genetically by luxSHp and also by addition of in vitro synthesised AI-2 or 4, 5-dihydroxy-2, 3-pentanedione (DPD, the precursor of AI-2). In contrast, exogenously added cysteine could not restore motility to the DeltaluxSHp mutant, confirming that AI-2 synthesis, but not the metabolic effect of LuxS was important. Microscopy showed reduced number and length of flagella in the DeltaluxSHp mutant. Immunoblotting identified decreased levels of FlaA and FlgE but not FlaB in the DeltaluxSHp mutant, and RT-PCR showed that the expression of flaA, flgE, motA, motB, flhA and fliI but not flaB was reduced. Addition of DPD but not cysteine to the DeltaluxSHp mutant restored flagellar gene transcription, and the number and length of flagella. CONCLUSIONS Our data show that as well as being a metabolic enzyme, H. pylori LuxS has an alternative role in regulation of motility by modulating flagellar transcripts and flagellar biosynthesis through production of the signalling molecule AI-2.
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In Helicobacter pylori, LuxS is a key enzyme in cysteine provision through a reverse transsulfuration pathway. J Bacteriol 2010; 192:1184-92. [PMID: 20061483 DOI: 10.1128/jb.01372-09] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
In many bacteria, LuxS functions as a quorum-sensing molecule synthase. However, it also has a second, more central metabolic function in the activated methyl cycle (AMC), which generates the S-adenosylmethionine required by methyltransferases and recycles the product via methionine. Helicobacter pylori lacks an enzyme catalyzing homocysteine-to-methionine conversion, rendering the AMC incomplete and thus making any metabolic role of H. pylori LuxS (LuxS(Hp)) unclear. Interestingly, luxS(Hp) is located next to genes annotated as cysK(Hp) and metB(Hp), involved in other bacteria in cysteine and methionine metabolism. We showed that isogenic strains carrying mutations in luxS(Hp), cysK(Hp), and metB(Hp) could not grow without added cysteine (whereas the wild type could), suggesting roles in cysteine synthesis. Growth of the DeltaluxS(Hp) mutant was restored by homocysteine or cystathionine and growth of the DeltacysK(Hp) mutant by cystathionine only. The DeltametB(Hp) mutant had an absolute requirement for cysteine. Metabolite analyses showed that S-ribosylhomocysteine accumulated in the DeltaluxS(Hp) mutant, homocysteine in the DeltacysK(Hp) mutant, and cystathionine in the DeltametB(Hp) mutant. This suggests that S-ribosylhomocysteine is converted by LuxS(Hp) to homocysteine (as in the classic AMC) and thence by CysK(Hp) to cystathionine and by MetB(Hp) to cysteine. In silico analysis suggested that cysK-metB-luxS were acquired by H. pylori from a Gram-positive source. We conclude that cysK-metB-luxS encode the capacity to generate cysteine from products of the incomplete AMC of H. pylori in a process of reverse transsulfuration. We recommend that the misnamed genes cysK(Hp) and metB(Hp) be renamed mccA (methionine-to-cysteine-conversion gene A) and mccB, respectively.
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Atherton JC, Blaser MJ. Coadaptation of Helicobacter pylori and humans: ancient history, modern implications. J Clin Invest 2009. [PMID: 19729845 DOI: 10.1172/jci38605.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Humans have been colonized by Helicobacter pylori for at least 50,000 years and probably throughout their evolution. H. pylori has adapted to humans, colonizing children and persisting throughout life. Most strains possess factors that subtly modulate the host environment, increasing the risk of peptic ulceration, gastric adenocarcinoma, and possibly other diseases. H. pylori genes encoding these and other factors rapidly evolve through mutation and recombination, changing the bacteria-host interaction. Although immune and physiologic responses to H. pylori also contribute to pathogenesis, humans have evolved in concert with the bacterium, and its recent absence throughout the life of many individuals has led to new human physiological changes. These may have contributed to recent increases in esophageal adenocarcinoma and, more speculatively, other modern diseases.
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Affiliation(s)
- John C Atherton
- Nottingham Digestive Diseases Centre Biomedical Research Unit and Institute of Infection, Immunity and Inflammation, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, United Kingdom.
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