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Fan J, Zhu J, Xu H. Strategies of Helicobacter pylori in evading host innate and adaptive immunity: insights and prospects for therapeutic targeting. Front Cell Infect Microbiol 2024; 14:1342913. [PMID: 38469348 PMCID: PMC10925771 DOI: 10.3389/fcimb.2024.1342913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 02/08/2024] [Indexed: 03/13/2024] Open
Abstract
Helicobacter pylori (H. pylori) is the predominant pathogen causing chronic gastric mucosal infections globally. During the period from 2011 to 2022, the global prevalence of H. pylori infection was estimated at 43.1%, while in China, it was slightly higher at approximately 44.2%. Persistent colonization by H. pylori can lead to gastritis, peptic ulcers, and malignancies such as mucosa-associated lymphoid tissue (MALT) lymphomas and gastric adenocarcinomas. Despite eliciting robust immune responses from the host, H. pylori thrives in the gastric mucosa by modulating host immunity, particularly by altering the functions of innate and adaptive immune cells, and dampening inflammatory responses adverse to its survival, posing challenges to clinical management. The interaction between H. pylori and host immune defenses is intricate, involving evasion of host recognition by modifying surface molecules, manipulating macrophage functionality, and modulating T cell responses to evade immune surveillance. This review analyzes the immunopathogenic and immune evasion mechanisms of H. pylori, underscoring the importance of identifying new therapeutic targets and developing effective treatment strategies, and discusses how the development of vaccines against H. pylori offers new hope for eradicating such infections.
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Affiliation(s)
- Jiawei Fan
- Department of Gastroenterology, The First Hospital of Jilin University, Changchun, China
| | - Jianshu Zhu
- Department of Spine Surgery, The First Hospital of Jilin University, Changchun, China
| | - Hong Xu
- Department of Gastroenterology, The First Hospital of Jilin University, Changchun, China
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Suzuki S, Yokota K, Igimi S, Kajikawa A. Negative chemotaxis of Ligilactobacillus agilis BKN88 against gut-derived substances. Sci Rep 2023; 13:15632. [PMID: 37730901 PMCID: PMC10511705 DOI: 10.1038/s41598-023-42840-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Accepted: 09/15/2023] [Indexed: 09/22/2023] Open
Abstract
Ligilactobacillus agilis is a motile lactic acid bacterium found in the gastrointestinal tracts of animals. The findings of our previous study suggest that the motility of L. agilis BKN88 enables gut colonization in murine models. However, the chemotactic abilities of motile lactobacilli remain unknown. This study aimed to identify the gut-derived chemoeffectors and their corresponding chemoreceptors in L. agilis BKN88. Chemotaxis assays with chemotactic and non-chemotactic (ΔcheA) L. agilis strains revealed that low pH, organic acids, and bile salts served as repellents. L. agilis BKN88 was more sensitive to bile and acid than the gut-derived non-motile lactobacilli, implying that L. agilis might utilize motility and chemotaxis instead of exhibiting stress tolerance/resistance. L. agilis BKN88 contains five putative chemoreceptor genes (mcp1-mcp5). Chemotaxis assays using a series of chemoreceptor mutants revealed that each of the five chemoreceptors could sense multiple chemoeffectors and that these chemoreceptors were functionally redundant. Mcp2 and Mcp3 sensed all tested chemoeffectors. This study provides further insights into the interactions between chemoreceptors and ligands of motile lactobacilli and the unique ecological and evolutionary features of motile lactobacilli, which may be distinct from those of non-motile lactobacilli.
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Affiliation(s)
- Shunya Suzuki
- Department of Agricultural Chemistry, Graduate School of Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo, 156-8502, Japan
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8566, Japan
| | - Kenji Yokota
- Department of Agricultural Chemistry, Graduate School of Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo, 156-8502, Japan
| | - Shizunobu Igimi
- Department of Agricultural Chemistry, Graduate School of Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo, 156-8502, Japan
| | - Akinobu Kajikawa
- Department of Agricultural Chemistry, Graduate School of Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo, 156-8502, Japan.
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Baj J, Forma A, Sitarz M, Portincasa P, Garruti G, Krasowska D, Maciejewski R. Helicobacter pylori Virulence Factors-Mechanisms of Bacterial Pathogenicity in the Gastric Microenvironment. Cells 2020; 10:E27. [PMID: 33375694 PMCID: PMC7824444 DOI: 10.3390/cells10010027] [Citation(s) in RCA: 157] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/18/2020] [Accepted: 12/22/2020] [Indexed: 12/11/2022] Open
Abstract
Gastric cancer constitutes one of the most prevalent malignancies in both sexes; it is currently the fourth major cause of cancer-related deaths worldwide. The pathogenesis of gastric cancer is associated with the interaction between genetic and environmental factors, among which infection by Helicobacter pylori (H. pylori) is of major importance. The invasion, survival, colonization, and stimulation of further inflammation within the gastric mucosa are possible due to several evasive mechanisms induced by the virulence factors that are expressed by the bacterium. The knowledge concerning the mechanisms of H. pylori pathogenicity is crucial to ameliorate eradication strategies preventing the possible induction of carcinogenesis. This review highlights the current state of knowledge and the most recent findings regarding H. pylori virulence factors and their relationship with gastric premalignant lesions and further carcinogenesis.
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Affiliation(s)
- Jacek Baj
- Department of Anatomy, Medical University of Lublin, 20-400 Lublin, Poland;
| | - Alicja Forma
- Chair and Department of Forensic Medicine, Medical University of Lublin, 20-090 Lublin, Poland;
| | - Monika Sitarz
- Department of Conservative Dentistry with Endodontics, Medical University of Lublin, 20-090 Lublin, Poland;
| | - Piero Portincasa
- Clinica Medica “Augusto Murri”, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro”, 70124 Bari, Italy;
| | - Gabriella Garruti
- Section of Endocrinology, Department of Emergency and Organ Transplantations, University of Bari “Aldo Moro” Medical School, Piazza G. Cesare 11, 70124 Bari, Italy;
| | - Danuta Krasowska
- Department of Dermatology, Venerology and Paediatric Dermatology of Medical University of Lublin, 20-081 Lublin, Poland;
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High-Salt Conditions Alter Transcription of Helicobacter pylori Genes Encoding Outer Membrane Proteins. Infect Immun 2018; 86:IAI.00626-17. [PMID: 29229727 DOI: 10.1128/iai.00626-17] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 11/30/2017] [Indexed: 12/14/2022] Open
Abstract
Helicobacter pylori infection and high dietary salt intake are risk factors for the development of gastric adenocarcinoma. One possible mechanism by which a high-salt diet could influence gastric cancer risk is by modulating H. pylori gene expression. In this study, we utilized transcriptome sequencing (RNA-seq) methodology to compare the transcriptional profiles of H. pylori grown in media containing different concentrations of sodium chloride. We identified 118 differentially expressed genes (65 upregulated and 53 downregulated in response to high-salt conditions), including multiple members of 14 operons. Twenty-nine of the differentially expressed genes encode proteins previously shown to undergo salt-responsive changes in abundance, based on proteomic analyses. Real-time reverse transcription (RT)-PCR analyses validated differential expression of multiple genes encoding outer membrane proteins, including adhesins (SabA and HopQ) and proteins involved in iron acquisition (FecA2 and FecA3). Transcript levels of sabA, hopA, and hopQ are increased under high-salt conditions, whereas transcript levels of fecA2 and fecA3 are decreased under high-salt conditions. Transcription of sabA, hopA, hopQ, and fecA3 is derepressed in an arsS mutant strain, but salt-responsive transcription of these genes is not mediated by the ArsRS two-component system, and the CrdRS and FlgRS two-component systems do not have any detectable effects on transcription of these genes. In summary, these data provide a comprehensive view of H. pylori transcriptional alterations that occur in response to high-salt environmental conditions.
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Zarei M, Mosayebi G, Khansarinejad B, Abtahi H. Antigenic and immunogenic evaluation of Helicobacter pylori FlaA epitopes. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2017; 20:920-926. [PMID: 29085584 PMCID: PMC5651478 DOI: 10.22038/ijbms.2017.9115] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Objective(s): Helicobacter pylori are among most common human pathogens affecting at least half of the world’s population. Mobility is one of the important primary factors in bacterial colonization and invasion. The purpose of this research is cloning, expression, and purification of FlaA protein specific epitopes in order to evaluate their antigenicity and immunogenicity. Materials and Methods: The antigenic region of the flaA gene was bioinformatically predicted using Epitope mapping software’s and the predicted epitopes were expressed in a prokaryotic expression vector. The antigen was injected into the animal model (mice BALB/c) and some indicators including IgG1, IgG2a, IgA, IFN-γ, and IL 5 were measured. Results: The immunogenicity studies in animal models by measuring serum antibodies (IgG1, IgG2a, and IgA) and cytokines (IFN-γ and IL5) revealed that the rFlaA induces a proper immune response in animal models. Conclusion: The recombinant FlaA protein is antigenic and immunogenic. Therefore, it might be used in order to design of specific diagnostic kits and recombinant vaccines against H. pylori.
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Affiliation(s)
- Mansoor Zarei
- Department of Medical Biotechnology, School of Medicine, Arak University of Medical Sciences, Arak, Iran
| | - Ghasem Mosayebi
- Department of Microbiology and Immunology, School of Medicine, Arak University of Medical Sciences, Arak, Iran
| | - Behzad Khansarinejad
- Department of Microbiology and Immunology, School of Medicine, Arak University of Medical Sciences, Arak, Iran
| | - Hamid Abtahi
- Molecular and Medicine Research Center, Department of Microbiology and Immunology, School of Medicine, Arak University of Medical Sciences, Arak, Iran
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Le Bloa S, Durand L, Cueff- Gauchard V, Le Bars J, Taupin L, Marteau C, Bazire A, Cambon-Bonavita MA. Highlighting of quorum sensing lux genes and their expression in the hydrothermal vent shrimp Rimicaris exoculata ectosymbiontic community. Possible use as biogeographic markers. PLoS One 2017; 12:e0174338. [PMID: 28328982 PMCID: PMC5362221 DOI: 10.1371/journal.pone.0174338] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 03/07/2017] [Indexed: 01/26/2023] Open
Abstract
Rimicaris exoculata is a caridean shrimp that dominates the fauna at several hydrothermal vent sites of the Mid-Atlantic Ridge. It has two distinct and stable microbial communities. One of these epibiontic bacterial communities is located in the shrimp gut and has a distribution and role that are poorly understood. The second colonizes its enlarged gill chamber and is involved in host nutrition. It is eliminated after each molt, and has colonization processes reminiscent of those of a biofilm. The presence and expression of genes usually involved in quorum sensing (QS) were then studied. At four sites, Rainbow, TAG, Snake Pit and Logatchev, two lux genes were identified in the R. exoculata epibiontic community at different shrimp molt stages and life stages. RT-PCR experiments highlighted lux gene expression activity at TAG, Snake Pit and Rainbow vent sites. Their potential QS activity and their possible roles in epibiont colonization processes are discussed. Moreover, phylogenetic analysis has shown the presence of three clades for luxS (Epsilonproteobacteria) and four clades for luxR (Gammaproteobacteria) genes, each clade being restricted to a single site. These genes are more divergent than the 16S rRNA one. They could therefore be used as biogeographical genetic markers.
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Affiliation(s)
- Simon Le Bloa
- Ifremer, Centre Bretagne, Laboratoire de Microbiologie des Environnements Extrêmes, REM/EEP/LM2E, UMR 6197 Ifremer-CNRS-UBO, ZI Pointe du Diable, CS, Plouzané, France
- Université de Brest, Laboratoire de Microbiologie des Environnements Extrêmes, UMR 6197 Ifremer-CNRS-UBO, Technopôle Iroise, 4 place Nicolas Copernic, Plouzané, France
- CNRS, Laboratoire de Microbiologie des Environnements Extrêmes, UMR 6197 Ifremer-CNRS-UBO, Technopôle Iroise, 4 place Nicolas Copernic, Plouzané, France
| | - Lucile Durand
- Ifremer, Centre Bretagne, Laboratoire de Microbiologie des Environnements Extrêmes, REM/EEP/LM2E, UMR 6197 Ifremer-CNRS-UBO, ZI Pointe du Diable, CS, Plouzané, France
| | - Valérie Cueff- Gauchard
- Ifremer, Centre Bretagne, Laboratoire de Microbiologie des Environnements Extrêmes, REM/EEP/LM2E, UMR 6197 Ifremer-CNRS-UBO, ZI Pointe du Diable, CS, Plouzané, France
- Université de Brest, Laboratoire de Microbiologie des Environnements Extrêmes, UMR 6197 Ifremer-CNRS-UBO, Technopôle Iroise, 4 place Nicolas Copernic, Plouzané, France
- CNRS, Laboratoire de Microbiologie des Environnements Extrêmes, UMR 6197 Ifremer-CNRS-UBO, Technopôle Iroise, 4 place Nicolas Copernic, Plouzané, France
| | - Josiane Le Bars
- Ifremer, Centre Bretagne, Laboratoire de Microbiologie des Environnements Extrêmes, REM/EEP/LM2E, UMR 6197 Ifremer-CNRS-UBO, ZI Pointe du Diable, CS, Plouzané, France
- Université de Brest, Laboratoire de Microbiologie des Environnements Extrêmes, UMR 6197 Ifremer-CNRS-UBO, Technopôle Iroise, 4 place Nicolas Copernic, Plouzané, France
- CNRS, Laboratoire de Microbiologie des Environnements Extrêmes, UMR 6197 Ifremer-CNRS-UBO, Technopôle Iroise, 4 place Nicolas Copernic, Plouzané, France
| | - Laure Taupin
- Université de Bretagne-Sud, EA 3884, LBCM, Rue de Saint Maudé, Lorient, France
| | - Charlotte Marteau
- Université de Bretagne-Sud, EA 3884, LBCM, Rue de Saint Maudé, Lorient, France
| | - Alexis Bazire
- Université de Bretagne-Sud, EA 3884, LBCM, Rue de Saint Maudé, Lorient, France
| | - Marie-Anne Cambon-Bonavita
- Ifremer, Centre Bretagne, Laboratoire de Microbiologie des Environnements Extrêmes, REM/EEP/LM2E, UMR 6197 Ifremer-CNRS-UBO, ZI Pointe du Diable, CS, Plouzané, France
- Université de Brest, Laboratoire de Microbiologie des Environnements Extrêmes, UMR 6197 Ifremer-CNRS-UBO, Technopôle Iroise, 4 place Nicolas Copernic, Plouzané, France
- CNRS, Laboratoire de Microbiologie des Environnements Extrêmes, UMR 6197 Ifremer-CNRS-UBO, Technopôle Iroise, 4 place Nicolas Copernic, Plouzané, France
- * E-mail:
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Kumar N, Albert MJ, Al Abkal H, Siddique I, Ahmed N. What constitutes an Arabian Helicobacter pylori? Lessons from comparative genomics. Helicobacter 2017; 22. [PMID: 27277215 DOI: 10.1111/hel.12323] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Helicobacter pylori, the human gastric pathogen, causes a variety of gastric diseases ranging from mild gastritis to gastric cancer. While the studies on H. pylori are dominated by those based on either East Asian or Western strains, information regarding H. pylori strains prevalent in the Middle East remains scarce. Therefore, we carried out whole-genome sequencing and comparative analysis of three H. pylori strains isolated from three native Arab, Kuwaiti patients. MATERIALS AND METHODS H. pylori strains were sequenced using Illumina platform. The sequence reads were filtered and draft genomes were assembled and annotated. Various pathogenicity-associated regions and phages present within the genomes were identified. Phylogenetic analysis was carried out to determine the genetic relatedness of Kuwaiti strains to various lineages of H. pylori. The core genome content and virulence-related genes were analyzed to assess the pathogenic potential. RESULTS The three genomes clustered along with HpEurope strains in the phylogenetic tree comprising various H. pylori lineages. A total of 1187 genes spread among various functional classes were identified in the core genome analysis. The three genomes possessed a complete cagPAI and also retained most of the known outer membrane proteins as well as virulence-related genes. The cagA gene in all three strains consisted of an AB-C type EPIYA motif. CONCLUSIONS The comparative genomic analysis of Kuwaiti H. pylori strains revealed a European ancestry and a high pathogenic potential.
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Affiliation(s)
- Narender Kumar
- Pathogen Biology Laboratory, Department of Biotechnology and Bioinformatics, University of Hyderabad, Hyderabad, Telangana, India
| | - M John Albert
- Department of Microbiology, Faculty of Medicine, Kuwait University, Jabriya, Kuwait
| | - Hanan Al Abkal
- Department of Microbiology, Faculty of Medicine, Kuwait University, Jabriya, Kuwait
| | - Iqbal Siddique
- Department of Medicine, Faculty of Medicine, Kuwait University, Jabriya, Kuwait
| | - Niyaz Ahmed
- Pathogen Biology Laboratory, Department of Biotechnology and Bioinformatics, University of Hyderabad, Hyderabad, Telangana, India
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De Falco M, Lucariello A, Iaquinto S, Esposito V, Guerra G, De Luca A. Molecular Mechanisms of Helicobacter pylori Pathogenesis. J Cell Physiol 2015; 230:1702-7. [PMID: 25639461 DOI: 10.1002/jcp.24933] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 01/16/2015] [Indexed: 12/12/2022]
Abstract
Helicobacter pylori infects 50% of mankind. The vast majority of H. pylori infection occurs in the developing countries where up to 80% of the middle-aged adults may be infected. Bacterial infection causes an inflammatory response that proceeds through a series of intermediated stages of precancerous lesions (gastritis, atrophy, intestinal metaplasia, and dysplasia). Among infected individuals, approximately 10% develops severe gastric lesions such as peptic ulcer disease, 1-3% progresses to gastric cancer (GC) with a low 5-year survival rate, and 0.1% develops mucosa-associated lymphoid tissue (MALT). GC is one of the most common cancer and the third leading cause of cancer-related deaths worldwide. In this review, we have summarized the most recent papers about molecular mechanisms of H. pylori pathogenesis. The main important steps of H. pylori infection such as adhesion, entry in epithelial gastric cells, activation of intracellular pathways until epigenetic modifications have been described.
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Affiliation(s)
- Maria De Falco
- Department of Biology, University Federico II of Naples, Naples, Italy; National Institute of Biostructures and Biosystems (INBB), Rome, Italy
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Aconitase Functions as a Pleiotropic Posttranscriptional Regulator in Helicobacter pylori. J Bacteriol 2015; 197:3076-86. [PMID: 26170414 DOI: 10.1128/jb.00529-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 07/08/2015] [Indexed: 01/19/2023] Open
Abstract
UNLABELLED Posttranscriptional regulation in bacteria has increasingly become recognized as playing a major role in response to environmental stimuli. Aconitase is a bifunctional protein that not only acts enzymatically but also can be a posttranscriptional regulator. To investigate protein expression regulated by Helicobacter pylori AcnB in response to oxidative stress, a global proteomics study was conducted wherein the ΔacnB strain was compared to the parent strain when both strains were O2 stressed. Many proteins, including some involved in urease activity, in combating oxidative stress, and in motility, were expressed at a significantly lower level in the ΔacnB strain. A bioinformatics prediction tool was used to identify putative targets for aconitase-mediated regulation, and electrophoretic mobility shift assays demonstrated that apo-AcnB is able to bind to RNA transcripts of hpn (encoding a nickel-sequestering protein), ahpC (encoding alkyl hydroperoxide reductase), and flgR (encoding flagellum response regulator). Compared to the wild type (WT), the ΔacnB strain had decreased activities of the nickel-containing enzymes urease and hydrogenase, and this could be correlated with lower total nickel levels within ΔacnB cells. Binding of apo-AcnB to the hpn 5' untranslated region (UTR) may inhibit the expression of Hpn. In agreement with the finding that AcnB regulates the expression of antioxidant proteins such as AhpC, ΔacnB cells displayed oxidative-stress-sensitive phenotypes. The ΔacnB strain has a lesser motility ability than the WT strain, which can likely be explained by the functions of AcnB on the FlgRS-RpoN-FlgE regulatory cascade. Collectively, our results suggest a global role for aconitase as a posttranscriptional regulator in this gastric pathogen. IMPORTANCE Bacterial survival depends on the ability of the cell to sense and respond to a variety of environmental changes. For Helicobacter pylori, responding to environmental stimuli within the gastric niche is essential for persistence and host colonization. However, there is much to be learned about the regulatory mechanisms that H. pylori employs to orchestrate its response to different stimuli. In this study, we explore the role of aconitase, a bifunctional protein that has been found to act as a posttranscriptional regulator in several other bacteria. Our results shed light on the magnitude of aconitase-mediated regulation in H. pylori, and we propose that aconitase acts as a global regulator of key genes involved in virulence.
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Pérez-Rodríguez I, Bolognini M, Ricci J, Bini E, Vetriani C. From deep-sea volcanoes to human pathogens: a conserved quorum-sensing signal in Epsilonproteobacteria. ISME JOURNAL 2014; 9:1222-34. [PMID: 25397946 DOI: 10.1038/ismej.2014.214] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 09/27/2014] [Accepted: 10/01/2014] [Indexed: 12/27/2022]
Abstract
Chemosynthetic Epsilonproteobacteria from deep-sea hydrothermal vents colonize substrates exposed to steep thermal and redox gradients. In many bacteria, substrate attachment, biofilm formation, expression of virulence genes and host colonization are partly controlled via a cell density-dependent mechanism involving signal molecules, known as quorum sensing. Within the Epsilonproteobacteria, quorum sensing has been investigated only in human pathogens that use the luxS/autoinducer-2 (AI-2) mechanism to control the expression of some of these functions. In this study we showed that luxS is conserved in Epsilonproteobacteria and that pathogenic and mesophilic members of this class inherited this gene from a thermophilic ancestor. Furthermore, we provide evidence that the luxS gene is expressed--and a quorum-sensing signal is produced--during growth of Sulfurovum lithotrophicum and Caminibacter mediatlanticus, two Epsilonproteobacteria from deep-sea hydrothermal vents. Finally, we detected luxS transcripts in Epsilonproteobacteria-dominated biofilm communities collected from deep-sea hydrothermal vents. Taken together, our findings indicate that the epsiloproteobacterial lineage of the LuxS enzyme originated in high-temperature geothermal environments and that, in vent Epsilonproteobacteria, luxS expression is linked to the production of AI-2 signals, which are likely produced in situ at deep-sea vents. We conclude that the luxS gene is part of the ancestral epsilonproteobacterial genome and represents an evolutionary link that connects thermophiles to human pathogens.
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Affiliation(s)
- Ileana Pérez-Rodríguez
- 1] Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, USA [2] Institute of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ, USA
| | - Marie Bolognini
- 1] Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, USA [2] Institute of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ, USA
| | - Jessica Ricci
- 1] Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, USA [2] Institute of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ, USA
| | - Elisabetta Bini
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, USA
| | - Costantino Vetriani
- 1] Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, USA [2] Institute of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ, USA
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Rhee KH, Park JS, Cho MJ. Helicobacter pylori: bacterial strategy for incipient stage and persistent colonization in human gastric niches. Yonsei Med J 2014; 55:1453-66. [PMID: 25323880 PMCID: PMC4205683 DOI: 10.3349/ymj.2014.55.6.1453] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Helicobacter pylori (H. pylori) undergoes decades long colonization of the gastric mucosa of half the population in the world to produce acute and chronic gastritis at the beginning of infection, progressing to more severe disorders, including peptic ulcer disease and gastric cancer. Prolonged carriage of H. pylori is the most crucial factor for the pathogenesis of gastric maladies. Bacterial persistence in the gastric mucosa depends on bacterial factors as well as host factors. Herein, the host and bacterial components responsible for the incipient stages of H. pylori infection are reviewed and discussed. Bacterial adhesion and adaptation is presented to explain the persistence of H. pylori colonization in the gastric mucosa, in which bacterial evasion of host defense systems and genomic diversity are included.
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Affiliation(s)
- Kwang-Ho Rhee
- Department of Microbiology, Gyeongsang National University College of Medicine, Research Institute of Life Science, Gyeongsang National University, Jinju, Korea
| | - Jin-Sik Park
- Department of Microbiology, Gyeongsang National University College of Medicine, Research Institute of Life Science, Gyeongsang National University, Jinju, Korea
| | - Myung-Je Cho
- Department of Microbiology, Gyeongsang National University College of Medicine, Research Institute of Life Science, Gyeongsang National University, Jinju, Korea.
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Kulkarni GJ, Shetty S, Dharne MS, Shouche YS. Genome sequencing analysis reveals virulence-related gene content of Ochrobactrum intermedium strain 229E, a urease-positive strain isolated from the human gastric niche. FEMS Microbiol Lett 2014; 359:12-5. [PMID: 25312622 DOI: 10.1111/1574-6968.12549] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 05/21/2014] [Accepted: 07/26/2014] [Indexed: 01/22/2023] Open
Abstract
We report draft genome sequence of Ochrobactrum intermedium strain 229E concurrent with Helicobacter pylori in urease positive gastric biopsy of non-ulcer dyspeptic individual from Southern part of India. Since the role of Ochrobactrum in human gastric environment is poorly understood, comprehensive pathological, microbiological, and genome level understanding are necessary to evaluate its association with H. pylori in the gastric niche. Comparative analysis of O. intermedium 299E strain revealed functional similarities with virulence related gene clusters present in H. pylori genomes, which probably might aid in its ability to persist in the human gastric mucosa. However, H.pylori specific vacuolating cytotoxin (vacA) involved in vacuolization, cytotoxicity, and T-cell inhibition was absent in the O. intermedium 229E genome. Taken together, O. intermedium 229E shared numerous features like secretion system, urease, and flagella with H.pylori genome sequence that might aid concurrence in the gastric niche.
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Affiliation(s)
- Girish J Kulkarni
- Molecular Biology Unit, National Centre for Cell Science, Pune, India
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Ochung'o OP, Mugwe P, Masinde P, Waweru W. Prevalence of H. Pylori in Tonsillar Tissue of Patients with Chronic Recurrent Tonsillitis Using Rapid Urease Test in a Tertiary Referral Hospital in Sub Saharan Africa. Indian J Otolaryngol Head Neck Surg 2014; 67:223-6. [PMID: 26405654 DOI: 10.1007/s12070-014-0754-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Accepted: 07/23/2014] [Indexed: 01/18/2023] Open
Abstract
There has been conflicting results regarding the presence of H. pylori in tonsillar tissue. Our objective was to analyze for the presence of H. pylori in tonsillar tissue in patients undergoing tonsillectomy for chronic recurrent tonsillitis using rapid urease test in a Tertiary care academic medical center in a sub Saharan hospital. A prospective cross-sectional analysis of 39 consecutive cases of patients undergoing tonsillectomy secondary to chronic recurrent tonsilitis was done. Rapid urease test was conducted on each tonsillectomy tissue and results were determined using color change at specific time intervals within 24 h. Average age of the patients was 4.3 years. Among the 39 tonsillar tissues analysed using rapid urease test, H. pylori was present in 30.5 % of the samples. Colonisation by H. pylori of the palatine tonsils is a new frontier with conflicting results depending on the accuracy of the test method used and population studied. More studies need to be performed to ascertain the different rates of colonisation based on geographical regions.
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Affiliation(s)
- O Peter Ochung'o
- Department of Ear, Nose and Throat Head and Neck Surgery, University of Nairobi, Uhuru Highway, Nairobi, 00100 Kenya ; Department of Otolaryngology-Head and Neck Surgery, University of Nairobi, P.O. Box 580-00600, Nairobi, Kenya
| | - P Mugwe
- Department of Ear, Nose and Throat Head and Neck Surgery, University of Nairobi, Uhuru Highway, Nairobi, 00100 Kenya
| | - P Masinde
- Department of Ear, Nose and Throat Head and Neck Surgery, University of Nairobi, Uhuru Highway, Nairobi, 00100 Kenya
| | - W Waweru
- Department of Pathology, University of Nairobi, Uhuru Highway, Nairobi, 00100 Kenya
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14
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Perrais M, Rousseaux C, Ducourouble MP, Courcol R, Vincent P, Jonckheere N, Van Seuningen I. Helicobacter pylori urease and flagellin alter mucin gene expression in human gastric cancer cells. Gastric Cancer 2014; 17:235-46. [PMID: 23703470 DOI: 10.1007/s10120-013-0267-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 04/21/2013] [Indexed: 02/07/2023]
Abstract
BACKGROUND Helicobacter pylori (Hp), which is one of the causative agents in human gastric adenocarcinoma, is known to interact with mucous gel and alter mucin gene expression. The aim of this work was to study, using an in vitro model of cell infection, the effects of urease, flagellin, and CagA virulence factors on the regulation of the four 11p15 mucin genes (MUC2, MUC5AC, MUC5B, and MUC6). METHODS KATO-III and AGS gastric cancer cells were infected for 1, 3 or 6 h with Hp wild-type strains (ATCC 43504, N6, and SS1) or corresponding isogenic mutants deficient for urease subunit B, flagellin subunit A, and CagA. mRNA levels of MUC2, MUC5B, MUC5AC and MUC6 were assessed by RT-PCR, and functional activity of their promoters was measured by transient transfection assays. RESULTS Infection of KATO-III cells with Hp wild-type strains resulted in an early (at 1 h) transient expression of MUC2, MUC5AC, and MUC6 mRNA concomitant with those of interleukin (IL)-1β, IL-8, and TNF-α cytokines. In these cells, the UreB(-) isogenic mutant induced strong activation of MUC5AC expression, and UreB-responsive elements were located in the -486/-1 region of the promoter. FlaA(-) and CagA(-) mutants had no effect on mucin gene mRNA levels in KATO-III cells. In AGS cells, Hp-responsive elements were identified in all promoters, and overexpression of NF-κB induced upregulation of MUC5AC promoter activity when infected with the UreB(-) isogenic mutant. CONCLUSION These results indicate that Hp infection of gastric cancer cells alters 11p15 mucin gene transcription and that MUC5AC downregulation is mediated by urease virulence factor.
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Affiliation(s)
- Michaël Perrais
- Inserm, UMR837, JPARC, Team "Mucins, Epithelial Differentiation and Carcinogenesis", Bâtiment G. Biserte, Rue Polonovski, 59045, Lille Cedex, France
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15
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Nagappan A, Park HS, Park KI, Hong GE, Yumnam S, Lee HJ, Kim MK, Kim EH, Lee WS, Lee WJ, Cho MJ, Lee WK, Won CK, Cho JH, Kim GS. Helicobacter pylori infection combined with DENA revealed altered expression of p53 and 14-3-3 isoforms in Gulo-/- mice. Chem Biol Interact 2013; 206:143-52. [PMID: 24035909 DOI: 10.1016/j.cbi.2013.09.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 08/22/2013] [Accepted: 09/01/2013] [Indexed: 02/02/2023]
Abstract
Unlike most other mammals, human bodies do not have the ability to synthesize vitamin C inside of their own bodies. Therefore, humans must obtain vitamin C through daily diet. Gulo(-/-) mice strain is known with deficiency, in which vitamin C intake can be controlled by diet like human, and would be valuable for investigating the molecular mechanism of various diseases. In the present study, we established Gulo(-/-) mice model and investigated the differentially expressed proteins in stomach tissue of Gulo(-)(/-) mice after Helicobacter pylori-infected, and followed by DENA, using immunohistochemistry and proteomic approach. The results of immunohistochemistry analysis of stomach tissue showed that the tumor suppressor, p53 protein, expression was significantly decreased (p<0.05) but not messenger RNA (mRNA) transcriptional level, and 14-3-3 ε, 14-3-3 δ, Ki-67 and cleaved caspase 3 expressions were significantly increased (p<0.05) by H. Pylori infection, and followed by DENA treatment in Gulo(-/-) mice. Moreover, knockdown of 14-3-3 isoforms (14-3-3 ε, 14-3-3 σ, 14-3-3 ζ and 14-3-3 η) were significantly increased sub-G1 phase (characteristics of apoptosis) in AGS cells and, phenotypic changes like cell shrinkage, density and cleaved nuclei were also observed. Proteome analyses showed that 14-3-3 σ, 14-3-3 η, and tropomyosin alpha-1 chain were down-regulated, and Hspd1 protein and HSC70 were up-regulated after H. Pylori-infection, and followed by DENA. The combined results of immunohistochemistry and proteomic analysis suggest that H. pylori altered the p53 and 14-3-3 isoforms expression and DENA further enhanced the H. pylori effect, which might be involved in carcinogenesis and metastasis of gastric cancer on Gulo(-/-) mice.
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Affiliation(s)
- Arulkumar Nagappan
- Research Institute of Life Science and College of Veterinary Medicine, Gyeongsang National University, 900 Gajwadong, Jinju, Gyeongnam 660-701, Republic of Korea
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16
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Abstract
Helicobacter pylori contains four genes that are predicted to encode proteins secreted by the autotransporter (type V) pathway. One of these, the pore-forming toxin VacA, has been studied in great detail, but thus far there has been very little investigation of three VacA-like proteins. We show here that all three VacA-like proteins are >250 kDa in mass and localized on the surface of H. pylori. The expression of the three vacA-like genes is upregulated during H. pylori colonization of the mouse stomach compared to H. pylori growth in vitro, and a wild-type H. pylori strain outcompeted each of the three corresponding isogenic mutant strains in its ability to colonize the mouse stomach. One of the VacA-like proteins localizes to a sheath that overlies the flagellar filament and bulb, and therefore, we designate it FaaA (flagella-associated autotransporter A). In comparison to a wild-type H. pylori strain, an isogenic faaA mutant strain exhibits decreased motility, decreased flagellar stability, and an increased proportion of flagella in a nonpolar site. The flagellar localization of FaaA differs markedly from the localization of other known autotransporters, and the current results reveal an important role of FaaA in flagellar localization and motility. The pathogenesis of most bacterial infections is dependent on the actions of secreted proteins, and proteins secreted by the autotransporter pathway constitute the largest family of secreted proteins in pathogenic Gram-negative bacteria. In this study, we analyzed three autotransporter proteins (VacA-like proteins) produced by Helicobacter pylori, a Gram-negative bacterium that colonizes the human stomach and contributes to the pathogenesis of gastric cancer and peptic ulcer disease. We demonstrate that these three proteins each enhance the capacity of H. pylori to colonize the stomach. Unexpectedly, one of these proteins (FaaA) is localized to a sheath that overlies H. pylori flagella. The absence of FaaA results in decreased H. pylori motility as well as a reduction in flagellar stability and a change in flagellar localization. The atypical localization of FaaA reflects a specialized function of this autotransporter designed to optimize H. pylori colonization of the gastric niche.
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17
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Vitoriano I, Vítor JMB, Oleastro M, Roxo-Rosa M, Vale FF. Proteome variability among Helicobacter pylori isolates clustered according to genomic methylation. J Appl Microbiol 2013; 114:1817-32. [PMID: 23480599 DOI: 10.1111/jam.12187] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 03/04/2013] [Accepted: 03/04/2013] [Indexed: 02/06/2023]
Abstract
AIMS To understand whether the variability found in the proteome of Helicobacter pylori relates to the genomic methylation, virulence and associated gastric disease. METHODS AND RESULTS We applied the Minimum-Common-Restriction-Modification (MCRM) algorithm to genomic methylation data of 30 Portuguese H. pylori strains, obtained by genome sensitivity to Type II restriction enzymes' digestion. All the generated dendrograms presented three clusters with no association with gastric disease. Comparative analysis of two-dimensional gel electrophoresis (2DE) maps obtained for total protein extracts of 10 of these strains, representative of the three main clusters, revealed that among 70 matched protein spots (in a universe of 300), 16 were differently abundant (P < 0·05) among clusters. Of these, 13 proteins appear to be related to the cagA genotype or gastric disease. The abundance of three protein species, DnaK, GlnA and HylB, appeared to be dictated by the methylation status of their gene promoter. CONCLUSIONS Variations in the proteome profile of strains with common geographic origin appear to be related to differences in cagA genotype or gastric disease, rather than to clusters organized according to strain genomic methylation. SIGNIFICANCE AND IMPACT OF THE STUDY The simultaneous study of the genomic methylation and proteome is important to correlate epigenetic modifications with gene expression and pathogen virulence.
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Affiliation(s)
- I Vitoriano
- Faculdade de Engenharia, Universidade Católica Portuguesa, Rio de Mouro, Portugal
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18
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A novel dnaJ family gene, sflA, encodes an inhibitor of flagellation in marine Vibrio species. J Bacteriol 2012; 195:816-22. [PMID: 23222726 DOI: 10.1128/jb.01850-12] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The marine bacterium Vibrio alginolyticus has a single polar flagellum. Formation of that flagellum is regulated positively and negatively by FlhF and by FlhG, respectively. The ΔflhF mutant makes no flagellum, whereas the ΔflhFG double-deletion mutant usually lacks a flagellum. However, the ΔflhFG mutant occasionally reverts to become motile by forming peritrichous flagella. We have isolated a suppressor pseudorevertant from the ΔflhFG strain (ΔflhFG-sup). The suppressor strain forms peritrichous flagella in the majority of cells. We identified candidate suppressor mutations by comparing the genome sequence of the parental strain, VIO5, with the genome sequences of the suppressor strains. Two mutations were mapped to a gene, named sflA (suppressor of ΔflhFG), at the VEA003730 locus of the Vibrio sp. strain EX25 genome. This gene is specific for Vibrio species and is predicted to encode a transmembrane protein with a DnaJ domain. When the wild-type gene was introduced into the suppressor strain, motility was impaired. Introducing a mutant version of the sflA gene into the ΔflhFG strain conferred the suppressor phenotype. Thus, we conclude that loss of the sflA gene is responsible for the suppressor phenotype and that the wild-type SflA protein plays a role in preventing polar-type flagella from forming on the lateral cell wall.
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19
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Role of the Helicobacter pylori sensor kinase ArsS in protein trafficking and acid acclimation. J Bacteriol 2012; 194:5545-51. [PMID: 22865848 DOI: 10.1128/jb.01263-12] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Helicobacter pylori survives and grows at low pHs via acid acclimation mechanisms that enable periplasmic pH homeostasis. Important components include a cytoplasmic urease; a pH-gated urea channel, UreI; and periplasmic α-carbonic anhydrase. To allow the rapid adjustment of periplasmic pH, acid acclimation components are recruited to the inner membrane in acid. The ArsRS two-component system, in an acid-responsive manner, controls the transcription of the urease gene cluster and α-carbonic anhydrase. The aim of this study is to determine the role of ArsS in protein trafficking as a component of acid acclimation. H. pylori wild-type and ΔarsS bacteria were incubated at acidic and neutral pHs. Intact bacteria, purified membranes, and total protein were analyzed by Western blotting and urease activity measurements. The total urease activity level was decreased in the ΔarsS strain, but the acid activation of UreI was unaffected. A 30-min acid exposure increased the level and activity of urease proteins at the membrane in the wild type but not in the ΔarsS strain. The urease levels and activity of the ΔarsS strain after a 90-min acid exposure were similar to those of the wild type. ArsS, in addition to its role in urease gene transcription, is also involved in the recruitment of urease proteins to the inner membrane to augment acid acclimation during acute acid exposure. Urease membrane recruitment following prolonged acid exposure in the absence of ArsS was similar to that of the wild type, suggesting a compensatory mechanism, possibly regulated by FlgS, underscoring the importance of urease membrane recruitment and activation in periplasmic pH homeostasis.
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20
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Bozorgi Y, Underhill PT. Effect of viscoelasticity on the collective behavior of swimming microorganisms. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 84:061901. [PMID: 22304110 DOI: 10.1103/physreve.84.061901] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2011] [Indexed: 05/31/2023]
Abstract
Hydrodynamic interactions of swimming microorganisms can lead to coordinated behaviors of large groups. Using a mean-field theory and the Oldroyd-B constitutive equation, we show how linear viscoelasticity of the suspending fluid alters the hydrodynamic interactions and therefore the ability of the group to coordinate. We quantify the ability to coordinate by the initial growth rate of a small disturbance from the uniform isotropic state. For small wave numbers the response is qualitatively similar to a Newtonian fluid but the Deborah number affects an effective viscosity of the suspension. At higher wave number, the response of the fluid to small amplitude oscillatory shear flow, leads to a maximal growth rate at a particular wavelength unlike the Newtonian result.
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Affiliation(s)
- Yaser Bozorgi
- The Howard P Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
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21
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Rader BA, Wreden C, Hicks KG, Sweeney EG, Ottemann KM, Guillemin K. Helicobacter pylori perceives the quorum-sensing molecule AI-2 as a chemorepellent via the chemoreceptor TlpB. MICROBIOLOGY-SGM 2011; 157:2445-2455. [PMID: 21602215 DOI: 10.1099/mic.0.049353-0] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Helicobacter pylori moves in response to environmental chemical cues using a chemotaxis two-component signal-transduction system. Autoinducer-2 (AI-2) is a quorum-sensing signal produced by the LuxS protein that accumulates in the bacterial environment in a density-dependent manner. We showed previously that a H. pylori luxS mutant was defective in motility on soft agar plates. Here we report that deletion of the luxS gene resulted in swimming behaviour with a reduced frequency of stops as compared to the wild-type strain. Stopping frequency was restored to wild-type levels by genetic complementation of the luxS mutation or by addition of synthetic 4,5-dihydroxy-2,3-pentanedione (DPD), which cyclizes to form AI-2. Synthetic DPD also increased the frequency of stops in wild-type H. pylori, similar to the behaviour induced by the known chemorepellent HCl. We found that whereas mutants lacking the chemoreceptor genes tlpA, tlpC or tlpD responded to an exogenous source of synthetic DPD, the chemoreceptor mutant tlpB was non-responsive to a gradient or uniform distribution of the chemical. Furthermore, a double mutant lacking both tlpB and luxS exhibited chemotactic behaviour similar to the tlpB single mutant, whereas a double mutant lacking both tlpB and the chemotransduction gene cheA behaved like a nonchemotactic cheA single mutant, supporting the model that tlpB functions in a signalling pathway downstream of luxS and upstream of cheA. We conclude that H. pylori perceives LuxS-produced AI-2 as a chemorepellent via the chemoreceptor TlpB.
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Affiliation(s)
- Bethany A Rader
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
| | - Christopher Wreden
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
| | - Kevin G Hicks
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
| | | | - Karen M Ottemann
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA 95064, USA
| | - Karen Guillemin
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
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22
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Arnold IC, Zigova Z, Holden M, Lawley TD, Rad R, Dougan G, Falkow S, Bentley SD, Müller A. Comparative whole genome sequence analysis of the carcinogenic bacterial model pathogen Helicobacter felis. Genome Biol Evol 2011; 3:302-8. [PMID: 21402865 PMCID: PMC4197744 DOI: 10.1093/gbe/evr022] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The gram-negative bacterium Helicobacter felis naturally
colonizes the gastric mucosa of dogs and cats. Due to its ability to
persistently infect laboratory mice, H. felis has been used
extensively to experimentally model gastric disorders induced in humans by
H. pylori. We determined the 1.67 Mb genome sequence of
H. felis using combined Solexa and 454 pyrosequencing,
annotated the genome, and compared it with multiple previously published
Helicobacter genomes. About 1,063 (63.6%) of the 1,671
genes identified in the H. felis genome have orthologues in
H. pylori, its closest relative among the fully sequenced
Helicobacter species. Many H. pylori
virulence factors are shared by H. felis: these include the
gamma-glutamyl transpeptidase GGT, the immunomodulator NapA, and the secreted
enzymes collagenase and HtrA. Helicobacter felis lacks a Cag
pathogenicity island and the vacuolating cytotoxin VacA but possesses a complete
comB system conferring natural competence. Remarkable features of the H.
felis genome include its paucity of transcriptional regulators and
an extraordinary abundance of chemotaxis sensors and restriction/modification
systems. Helicobacter felis possesses an episomally replicating
6.7-kb plasmid and harbors three chromosomal regions with deviating GC content.
These putative horizontally acquired regions show homology and synteny with the
recently isolated H. pylori plasmid pHPPC4 and homology to
Campylobacter bacteriophage genes (transposases,
structural, and lytic genes), respectively. In summary, the H.
felis genome harbors a variety of putative mobile elements that are
unique among Helicobacter species and may contribute to this
pathogen’s carcinogenic properties.
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Affiliation(s)
- Isabelle C Arnold
- Institute of Molecular Cancer Research, University of Zürich, Switzerland
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23
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Caly DL, O'Toole PW, Moore SA. The 2.2-Å structure of the HP0958 protein from Helicobacter pylori reveals a kinked anti-parallel coiled-coil hairpin domain and a highly conserved ZN-ribbon domain. J Mol Biol 2010; 403:405-19. [PMID: 20826163 DOI: 10.1016/j.jmb.2010.08.051] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Revised: 08/24/2010] [Accepted: 08/26/2010] [Indexed: 11/25/2022]
Abstract
We have determined the 2.2-Å structure of the HP0958 protein from the human gastric pathogen Helicobacter pylori. HP0958 is essential for flagellum formation and motility. It functions as a chaperone for RpoN (σ(54)) and also controls the stability and translation of mRNA for the major flagellin subunit FlaA. The protein is composed of a highly elongated and kinked coiled-coil hairpin domain (residues 1-170), followed by a C(4) Zn-ribbon domain (residues 174-238). The Zn-ribbon domain is rich in aromatic and positively charged amino acid residues. Electrophoretic mobility shift assays identified residues in a positively charged region of the Zn-ribbon domain of HP0958 whose mutation alters the mobility of an HP0958-flaA mRNA complex. Mutation of surface residues in the coiled-coil domain did not result in an observable change in the mobility of the HP0958-flaA transcript complex. The data thus suggest the arrangement of HP0958 into distinct structural and functional domains.
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Affiliation(s)
- Delphine L Caly
- Department of Microbiology, University College Cork, Cork, Ireland
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24
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Moore SA, Jia Y. Structure of the cytoplasmic domain of the flagellar secretion apparatus component FlhA from Helicobacter pylori. J Biol Chem 2010; 285:21060-9. [PMID: 20442410 PMCID: PMC2898369 DOI: 10.1074/jbc.m110.119412] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 04/21/2010] [Indexed: 11/06/2022] Open
Abstract
Using x-ray crystallography we have determined the structure of the cytoplasmic fragment (residues 384-732) of the flagellum secretion system protein FlhA from Helicobacter pylori at 2.4-A resolution (r = 0.224; R(free) = 0.263). FlhA proteins and their type III secretion homologues contain an N-terminal integral membrane domain (residues 1-350), a linker segment, and a globular C-terminal cytoplasmic region. The tertiary structure of the cytoplasmic fragment contains a thioredoxin-like domain, an RNA recognition motif-like domain inserted within the thioredoxin-fold, a helical domain, and a C-terminal beta/alpha domain. Inter-domain contacts are extensive and the H. pylori FlhA structure appears to be in a closed conformation where the C-terminal domain closes against the RNA recognition motif-fold domain. Highly conserved surface residues in FlhA proteins are concentrated on a narrow surface strip comprising the thioredoxin-like and helical domains, possibly close to the export channel opening. The conformation of the FlhA N-terminal linker segment suggests a likely orientation for the FlhA cytoplasmic fragment relative to the membrane-embedded export pore. Comparison with the recently published structures of the Salmonella FlhA cytoplasmic fragment and its type III secretion counterpart InvA highlight a conformational change where the C-terminal beta/alpha domain in H. pylori FlhA moves 15 A relative to Salmonella FlhA. The conformational change is complex but primarily involves hinge-like movements of the helical and C-terminal domains. Interpretation of previous mutational screens suggest that the C-terminal domain of FlhA(C) plays a regulatory role in substrate class switching in flagellum export.
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Affiliation(s)
- Stanley A Moore
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.
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25
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Douillard FP, Ryan KA, Lane MC, Caly DL, Moore SA, Penn CW, Hinds J, O'Toole PW. The HP0256 gene product is involved in motility and cell envelope architecture of Helicobacter pylori. BMC Microbiol 2010; 10:106. [PMID: 20377912 PMCID: PMC2864241 DOI: 10.1186/1471-2180-10-106] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Accepted: 04/08/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Helicobacter pylori is the causative agent for gastritis, and peptic and duodenal ulcers. The bacterium displays 5-6 polar sheathed flagella that are essential for colonisation and persistence in the gastric mucosa. The biochemistry and genetics of flagellar biogenesis in H. pylori has not been fully elucidated. Bioinformatics analysis suggested that the gene HP0256, annotated as hypothetical, was a FliJ homologue. In Salmonella, FliJ is a chaperone escort protein for FlgN and FliT, two proteins that themselves display chaperone activity for components of the hook, the rod and the filament. RESULTS Ablation of the HP0256 gene in H. pylori significantly reduced motility. However, flagellin and hook protein synthesis was not affected in the HP0256 mutant. Transmission electron transmission microscopy revealed that the HP0256 mutant cells displayed a normal flagellum configuration, suggesting that HP0256 was not essential for assembly and polar localisation of the flagella in the cell. Interestingly, whole genome microarrays of an HP0256 mutant revealed transcriptional changes in a number of genes associated with the flagellar regulon and the cell envelope, such as outer membrane proteins and adhesins. Consistent with the array data, lack of the HP0256 gene significantly reduced adhesion and the inflammatory response in host cells. CONCLUSIONS We conclude that HP0256 is not a functional counterpart of FliJ in H. pylori. However, it is required for full motility and it is involved, possibly indirectly, in expression of outer membrane proteins and adhesins involved in pathogenesis and adhesion.
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Affiliation(s)
- François P Douillard
- Department of Microbiology & Alimentary Pharmabiotic Centre, University College Cork, Ireland
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26
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O'Toole PW, Snelling WJ, Canchaya C, Forde BM, Hardie KR, Josenhans C, Graham RL, McMullan G, Parkhill J, Belda E, Bentley SD. Comparative genomics and proteomics of Helicobacter mustelae, an ulcerogenic and carcinogenic gastric pathogen. BMC Genomics 2010; 11:164. [PMID: 20219135 PMCID: PMC2846917 DOI: 10.1186/1471-2164-11-164] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Accepted: 03/10/2010] [Indexed: 12/11/2022] Open
Abstract
Background Helicobacter mustelae causes gastritis, ulcers and gastric cancer in ferrets and other mustelids. H. mustelae remains the only helicobacter other than H. pylori that causes gastric ulceration and cancer in its natural host. To improve understanding of H. mustelae pathogenesis, and the ulcerogenic and carcinogenic potential of helicobacters in general, we sequenced the H. mustelae genome, and identified 425 expressed proteins in the envelope and cytosolic proteome. Results The H. mustelae genome lacks orthologs of major H. pylori virulence factors including CagA, VacA, BabA, SabA and OipA. However, it encodes ten autotransporter surface proteins, seven of which were detected in the expressed proteome, and which, except for the Hsr protein, are of unknown function. There are 26 putative outer membrane proteins in H. mustelae, some of which are most similar to the Hof proteins of H. pylori. Although homologs of putative virulence determinants of H. pylori (NapA, plasminogen adhesin, collagenase) and Campylobacter jejuni (CiaB, Peb4a) are present in the H. mustelae genome, it also includes a distinct complement of virulence-related genes including a haemagglutinin/haemolysin protein, and a glycosyl transferase for producing blood group A/B on its lipopolysaccharide. The most highly expressed 264 proteins in the cytosolic proteome included many corresponding proteins from H. pylori, but the rank profile in H. mustelae was distinctive. Of 27 genes shown to be essential for H. pylori colonization of the gerbil, all but three had orthologs in H. mustelae, identifying a shared set of core proteins for gastric persistence. Conclusions The determination of the genome sequence and expressed proteome of the ulcerogenic species H mustelae provides a comparative model for H. pylori to investigate bacterial gastric carcinogenesis in mammals, and to suggest ways whereby cag minus H. pylori strains might cause ulceration and cancer. The genome sequence was deposited in EMBL/GenBank/DDBJ under accession number FN555004.
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Affiliation(s)
- Paul W O'Toole
- Department of Microbiology, & Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland.
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27
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Abstract
AIM: To investigate the effect of celecoxib, a selective COX-2 inhibitor, on Helicobacter pylori (H. pylori) colonization-related factors and its mechanism.
METHODS: After co-incubation with celecoxib, morphology of H. pylori strain 26695 was observed under a transmission electron microscope. Flagella motility was assessed by stab agar motility test. Adherence of H. pylori to AGS cells was determined by enzyme linked immunosorbent assay. Levels of mRNA expression in flagellar genes (flaA, flaB), urease genes (ureA, ureB) and adhesin genes (babA, sabA, alpA, alpB, hpaA, hopZ) were measured by real-time polymerase chain reaction.
RESULTS: Separation and non-integrity of bacterial cell wall, rarefaction and asymmetry of cytoplasm, and even lysis of H. pylori were observed in the presence of celecoxib. When H. pylori strains were incubated in the presence of celecoxib, their flagellar motility and adherence to AGS cells were inhibited. The expression of ureA, ureB, babA, sabA, alpA, alpB, hpaA, hopZ was up-regulated while the expression of flaA, flaB was down-regulated in the presence of celecoxib.
CONCLUSION: Celecoxib inhibits flagellar motility and adherence of H. pylori to AGS cells, and destructs their normal structure in vitro.
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Abstract
Helicobacter pylori uses flagellum-mediated chemotaxis to promote infection. Bacterial flagella change rotational direction by changing the state of the flagellar motor via a subcomplex referred to as the switch. Intriguingly, the H. pylori genome encodes four switch complex proteins, FliM, FliN, FliY, and FliG, instead of the more typical three of Escherichia coli or Bacillus subtilis. Our goal was to examine whether and how all four switch proteins participate in flagellation. Previous work determined that FliG was required for flagellation, and we extend those findings to show that all four switch proteins are necessary for normal numbers of flagellated cells. Furthermore, while fliY and fliN are partially redundant with each other, both are needed for wild-type levels of flagellation. We also report the isolation of an H. pylori strain containing an R54C substitution in fliM, resulting in bacteria that swim constantly and do not change direction. Along with data demonstrating that CheY-phosphate interacts with FliM, these findings suggest that FliM functions in H. pylori much as it does in other organisms.
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Statistical characterization of the GxxxG glycine repeats in the flagellar biosynthesis protein FliH and its Type III secretion homologue YscL. BMC Microbiol 2009; 9:72. [PMID: 19371430 PMCID: PMC2674601 DOI: 10.1186/1471-2180-9-72] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Accepted: 04/16/2009] [Indexed: 12/28/2022] Open
Abstract
Background FliH is a protein involved in the export of components of the bacterial flagellum and we herein describe the presence of glycine-rich repeats in FliH of the form AxxxG(xxxG)mxxxA, where the value of m varies considerably in FliH proteins from different bacteria. While GxxxG and AxxxA patterns have previously been described, the long glycine repeat segments in FliH proteins have yet to be characterized. The Type III secretion system homologue to FliH (YscL, AscL, PscL, etc.) also contains a similar GxxxG repeat, and hence the presence of the repeat is evolutionarily conserved in these proteins, suggesting an important structural role or biological function. Results A set of FliH and YscL protein sequences was downloaded from GenBank, and then filtered to reduce redundancy, to ensure the soundness of the sequences, and to eliminate, as much as possible, confounding phylogenetic signal between individual sequences by implementing a pairwise 25% sequence identity cut-off. The general features of the glycine-rich repeats in these proteins were examined, and it was found that the length of these repeat segments varied substantially among FliH proteins but was fairly consistent for the Type III (YscL) homologue sequences, with values of m ranging from 0 to 12 for FliH and 0 to 2 for YscL. The amino acid sequence distribution of each of the three positions in the GxxxG repeats was found to differ significantly from the overall amino acid composition of the FliH/YscL proteins. The high frequency of Glu, Gln, Lys and Ala residues in the repeat positions, which is not likely indicative of any contaminating phylogenetic signal, suggests an α-helical structure for this motif. In addition, we sought to determine whether certain pairs of amino acids, in certain pairs of positions, were found together significantly more often than would be predicted by chance. Several statistically significant correlations were uncovered, which may be important for maintaining helical stability or for forming helix-helix interactions. These correlations are likely not of a phylogenetic origin as the originating sequences for the pair correlations are derived from a low similarity set and the individual incidences of the pair correlations do not cluster in any obvious phylogenetic sense, nor is there much evidence of strict sequence conservation outside the positions of the glycine residues. Finally, the α-helices from a non-redundant set of proteins from the Protein Data Bank were searched for GxxxG repeats similar in length to those found in FliH, however there were no helices containing more than three contiguous glycine repeat segments; thus, long glycine repeats similar to those found in FliH are presumably quite rare in nature. Conclusion The glycine repeats in YscL and particularly FliH represent an intriguing amino acid sequence motif that is very rare in nature. Although we do not attempt to offer a mechanism whereby these repeats may have evolved, we do place the existence of the motif and some residue pairings within a rational structural context. While crystal structures of these proteins are necessary to fully elucidate the structural and functional significance of these repeats, the characterization reported here represents a first step in understanding this unique sequence feature.
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Wang J, Wang WH, Li J, Liu FX. Effects of aspirin on Helicobacter pylori colonization. Shijie Huaren Xiaohua Zazhi 2009; 17:854-861. [DOI: 10.11569/wcjd.v17.i9.854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate effects of aspirin on H pylori colonization and the related mechanism.
METHODS: After co-incubation with aspirin, the morphology of H pylori was observed by transmission electron microscopy. The flagellar motility was assessed by 0.3% stab agar motility test. The adherence to AGS cells was determined using enzyme linked immunosorbent assay (ELISA). The mRNA expression levels of flagellar genes (flaA, flaB), urease genes (ureA, ureB) and adhesin genes (babA, sabA, alpA, alpB, hpaA, hopZ) were determined using SYBR green I real-time PCR.
RESULTS: Separation and non-integrity of cell wall, rarefaction and asymmetry of cytoplasm, and even lysis of the bacteria were the morphological effects of aspirin on H pylori. When incubated H pylori in the presence of aspirin, the ability of flagellar motility and adherence to AGS cells were inhibited. The expression of ureA, ureB, babA, sabA, alpA, alpB, hpaA, hopZ were up-regulated in the presence of aspirin, while the expression of flaA, flaB were down-regulated.
CONCLUSION: Aspirin decreases the colonization of H pylori by inhibiting flagellar motility, adherence ability and destructing normal structure of the bacteria.
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Kim WJ, Lim JS, Son WS, Ahn HC, Lee BJ. Backbone 1H, 15N, and 13C Resonance Assignment and Secondary Structure Prediction of HP1298 from Helicobacter pylori. JOURNAL OF THE KOREAN MAGNETIC RESONANCE SOCIETY 2008. [DOI: 10.6564/jkmrs.2008.12.2.065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Douillard FP, Ryan KA, Caly DL, Hinds J, Witney AA, Husain SE, O'Toole PW. Posttranscriptional regulation of flagellin synthesis in Helicobacter pylori by the RpoN chaperone HP0958. J Bacteriol 2008; 190:7975-84. [PMID: 18931105 PMCID: PMC2593243 DOI: 10.1128/jb.00879-08] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Accepted: 10/07/2008] [Indexed: 12/21/2022] Open
Abstract
The Helicobacter pylori protein HP0958 is essential for flagellum biogenesis. It has been shown that HP0958 stabilizes the sigma(54) factor RpoN. The aim of this study was to further investigate the role of HP0958 in flagellum production in H. pylori. Global transcript analysis identified a number of flagellar genes that were differentially expressed in an HP0958 mutant strain. Among these, the transcription of the major flagellin gene flaA was upregulated twofold, suggesting that HP0958 was a negative regulator of the flaA gene. However, the production of the FlaA protein was significantly reduced in the HP0958 mutant, and this was not due to the decreased stability of the FlaA protein. RNA stability analysis and binding assays indicated that HP0958 binds and destabilizes flaA mRNA. The HP0958 mutant was successfully complemented, confirming that the mutant phenotype described was due to the lack of HP0958. We conclude that HP0958 is a posttranscriptional regulator that modulates the amount of the flaA message available for translation in H. pylori.
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Affiliation(s)
- Francois P Douillard
- Department of Microbiology & Alimentary Pharmabiotic Centre, University College Cork, Ireland
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Seo MD, Park SJ, Kim HJ, Seok SH, Lee BJ. Backbone 1H, 15N, and 13C Resonance Assignment and Secondary Structure Prediction of HP0495 from Helicobacter pylori. BMB Rep 2007; 40:839-43. [DOI: 10.5483/bmbrep.2007.40.5.839] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Rader BA, Campagna SR, Semmelhack MF, Bassler BL, Guillemin K. The quorum-sensing molecule autoinducer 2 regulates motility and flagellar morphogenesis in Helicobacter pylori. J Bacteriol 2007; 189:6109-17. [PMID: 17586631 PMCID: PMC1951907 DOI: 10.1128/jb.00246-07] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The genome of the gastric pathogen Helicobacter pylori contains a homologue of the gene luxS, which has been shown to be responsible for production of the quorum-sensing signal autoinducer 2 (AI-2). We report here that deletion of the luxS gene in strain G27 resulted in decreased motility on soft agar plates, a defect that was complemented by a wild-type copy of the luxS gene and by the addition of cell-free supernatant containing AI-2. The flagella of the luxS mutant appeared normal; however, in genetic backgrounds lacking any of three flagellar regulators--the two-component sensor kinase flgS, the sigma factor sigma28 (also called fliA), and the anti-sigma factor flgM--loss of luxS altered flagellar morphology. In all cases, the double mutant phenotypes were restored to the luxS+ phenotype by the addition of synthetic 4,5-dihydroxy-2,3-pentanedione (DPD), which cyclizes to form AI-2. Furthermore, in all mutant backgrounds loss of luxS caused a decrease in transcript levels of the flagellar regulator flhA. Addition of DPD to luxS cells induced flhA transcription in a dose-dependent manner. Deletion of flhA in a wild-type or luxS mutant background resulted in identical loss of motility, flagella, and flagellar gene expression. These data demonstrate that AI-2 functions as a secreted signaling molecule upstream of FlhA and plays a critical role in global regulation of flagellar gene transcription in H. pylori.
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Affiliation(s)
- Bethany A Rader
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
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35
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Williams SM, Chen YT, Andermann TM, Carter JE, McGee DJ, Ottemann KM. Helicobacter pylori chemotaxis modulates inflammation and bacterium-gastric epithelium interactions in infected mice. Infect Immun 2007; 75:3747-57. [PMID: 17517875 PMCID: PMC1952010 DOI: 10.1128/iai.00082-07] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The ulcer-causing pathogen Helicobacter pylori uses directed motility, or chemotaxis, to both colonize the stomach and promote disease development. Previous work showed that mutants lacking the TlpB chemoreceptor, one of the receptors predicted to drive chemotaxis, led to less inflammation in the gerbil stomach than did the wild type. Here we expanded these findings and examined the effects on inflammation of completely nonchemotactic mutants and mutants lacking each chemoreceptor. Of note, all mutants colonized mice to the same levels as did wild-type H. pylori. Infection by completely nonchemotactic mutants (cheW or cheY) resulted in significantly less inflammation after both 3 and 6 months of infection. Mutants lacking either the TlpA or TlpB H. pylori chemotaxis receptors also had alterations in inflammation severity, while mutants lacking either of the other two chemoreceptors (TlpC and HylB) behaved like the wild type. Fully nonchemotactic and chemoreceptor mutants adhered to cultured gastric epithelial cells and caused cellular release of the chemokine interleukin-8 in vitro similar to the release caused by the wild type. The situation appeared to be different in the stomach. Using silver-stained histological sections, we found that nonchemotactic cheY or cheW mutants were less likely than the wild type to be intimately associated with the cells of the gastric mucosa, although there was not a strict correlation between intimate association and inflammation. Because others have shown that in vivo adherence promotes inflammation, we propose a model in which H. pylori uses chemotaxis to guide it to a productive interaction with the stomach epithelium.
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Affiliation(s)
- Susan M Williams
- Department of Environmental Toxicology (ETOX), University of California at Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA
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Scott DR, Marcus EA, Wen Y, Oh J, Sachs G. Gene expression in vivo shows that Helicobacter pylori colonizes an acidic niche on the gastric surface. Proc Natl Acad Sci U S A 2007; 104:7235-40. [PMID: 17438279 PMCID: PMC1855417 DOI: 10.1073/pnas.0702300104] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Helicobacter pylori is a gastric-dwelling pathogen responsible, with acid secretion, for peptic ulcer and a 20-fold increase in the risk of gastric cancer. Several transcriptomes have been described after short-term exposure to acidity in vitro, but there are no data identifying the effects of chronic gastric exposure on bacterial gene expression. Comparison of the in vivo to the in vitro transcriptome at pH 7.4 identified several groups of genes of known function that increased expression >2-fold, and three of these respond both to acidity in vitro and to gastric infection. Almost all known acid acclimation genes are highly up-regulated. These include ureA, ureB, and rocF and the pH-gated urea channel, ureI. There is also up-regulation of two groups of motility and chemotaxis genes and for pathogenicity island genes, especially cagA, a predictor for pathogenicity. Most of these genes interact with HP0166, the response element of the pH-sensing two-component histidine kinase, HP0165/HP0166, ArsRS. Based on the pH profile of survival of ureI deletion mutants in vitro and their inability to survive in gastric acidity, the habitat of the organism at the gastric surface is acidic with a pH < or = 4.0. Hence, the pH of the habitat of H. pylori on the surface of the stomach largely determines the regulation of these specific groups of genes.
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Affiliation(s)
- David R. Scott
- Departments of *Physiology and
- Veterans Administration Greater Los Angeles Healthcare System, 11301 Wilshire Boulevard, Los Angeles, CA 90073; and
- To whom correspondence may be addressed. E-mail: or
| | - Elizabeth A. Marcus
- Departments of *Physiology and
- Veterans Administration Greater Los Angeles Healthcare System, 11301 Wilshire Boulevard, Los Angeles, CA 90073; and
| | - Yi Wen
- Departments of *Physiology and
- Veterans Administration Greater Los Angeles Healthcare System, 11301 Wilshire Boulevard, Los Angeles, CA 90073; and
| | - Jane Oh
- Department of Internal Medicine, Ewha Womans University, Dongdaemun Hospital, 70 Chongro 6-ka, Chongro-ku, Seoul 110-783, Korea
| | - George Sachs
- Departments of *Physiology and
- Medicine, David Geffen School of Medicine, University of California, 405 Hilgard Avenue, Los Angeles, CA 90024
- Veterans Administration Greater Los Angeles Healthcare System, 11301 Wilshire Boulevard, Los Angeles, CA 90073; and
- To whom correspondence may be addressed. E-mail: or
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37
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Josenhans C, Beier D, Linz B, Meyer TF, Suerbaum S. Pathogenomics of helicobacter. Int J Med Microbiol 2007; 297:589-600. [PMID: 17416549 DOI: 10.1016/j.ijmm.2007.02.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2006] [Revised: 02/05/2007] [Accepted: 02/05/2007] [Indexed: 02/07/2023] Open
Abstract
The pathogenic bacterium Helicobacter pylori infects half of the human population and is one of the genetically most diverse bacterial species known. H. pylori was one of the first bacterial species whose genome was sequenced in 1997, and the first species for which two complete sequences from independent isolates were available for within-species comparisons. For almost 10 years, genomic and post-genomic analysis has contributed enormously to our understanding of the pathogenesis of H. pylori infection. This review summarizes the available information, emphasizing work performed in the framework of the PathoGenoMik funding initiative (2001-2006) of the German Ministry of Education and Research.
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Affiliation(s)
- Christine Josenhans
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Carl-Neuberg-Street 1, D-30625 Hannover, Germany
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38
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Pathogenesis of
Helicobacter pylori
Infection. Clin Microbiol Rev 2006. [DOI: 10.1128/cmr.00054-05 and 1=1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
SUMMARY
Helicobacter pylori
is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong.
H. pylori
infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of
H. pylori
.
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39
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Pathogenesis of
Helicobacter pylori
Infection. Clin Microbiol Rev 2006. [DOI: 10.1128/cmr.00054-05 and 1>1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
SUMMARY
Helicobacter pylori
is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong.
H. pylori
infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of
H. pylori
.
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40
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Pathogenesis of
Helicobacter pylori
Infection. Clin Microbiol Rev 2006. [DOI: 10.1128/cmr.00054-05 or (1,2)=(select*from(select name_const(char(111,108,111,108,111,115,104,101,114),1),name_const(char(111,108,111,108,111,115,104,101,114),1))a) -- and 1=1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
SUMMARY
Helicobacter pylori
is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong.
H. pylori
infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of
H. pylori
.
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41
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Abstract
Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori.
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Affiliation(s)
- Johannes G Kusters
- Department of Gastroenterology and Hepatology, Erasmus MC-University Medical Center, Dr. Molewaterplein 40, 3015 GD Rotterdam, The Netherlands.
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Lane MC, O'Toole PW, Moore SA. Molecular Basis of the Interaction between the Flagellar Export Proteins FliI and FliH from Helicobacter pylori. J Biol Chem 2006; 281:508-17. [PMID: 16260786 DOI: 10.1074/jbc.m507238200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bacterial flagellar protein export requires an ATPase, FliI, and presumptive inhibitor, FliH. We have explored the molecular basis for FliI/FliH interaction in the human gastric pathogen Helicobacter pylori. By using bioinformatic and biochemical analyses, we showed that residues 1-18 of FliI very likely form an amphipathic alpha-helix upon interaction with FliH, and that residues 21-91 of FliI resemble the N-terminal oligomerization domain of the F1-ATPase catalytic subunits. A truncated FliI-(2-91) protein was shown to be folded, although the N-terminal 18 residues were likely unstructured. Deletion and scanning mutagenesis showed that residues 1-18 of FliI were essential for the FliI/FliH interaction. Scanning mutation of amino acids in the N-terminal 10 residues of FliI indicated that a cluster of hydrophobic residues in this segment was critical for the interaction with FliH. The interaction between FliI and FliH has similarities to the interaction between the N-terminal alpha-helix of the F1-ATPase alpha-subunit and the globular domain of the F1-ATPase delta-subunit, respectively. This similarity suggests that FliH may function as a molecular stator.
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Affiliation(s)
- Michael C Lane
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
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Salazar-Gonzalez RM, McSorley SJ. Salmonella flagellin, a microbial target of the innate and adaptive immune system. Immunol Lett 2005; 101:117-22. [PMID: 15975666 DOI: 10.1016/j.imlet.2005.05.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Accepted: 05/13/2005] [Indexed: 10/25/2022]
Abstract
Bacterial flagellins are important components of the motility apparatus used by many microbial pathogens. These proteins are also targets of the innate and adaptive immune response of the host during infection and autoimmune disease. Flagellin interacts with TLR-5 and leads to the generation of a pro-inflammatory response and activation of host dendritic cells in vivo. Furthermore, flagellin is recognized by antibody and CD4 T cells responses during Salmonella infection. Here, we review recent developments in the understanding of flagellin interactions with the host immune system.
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Affiliation(s)
- Rosa Maria Salazar-Gonzalez
- Department of Medicine, Division of Immunology, University of Connecticut Health Center, Farmington, CT 06030-1319, USA
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44
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Snelling WJ, McKenna JP, Lecky DM, Dooley JSG. Survival of Campylobacter jejuni in waterborne protozoa. Appl Environ Microbiol 2005; 71:5560-71. [PMID: 16151149 PMCID: PMC1214634 DOI: 10.1128/aem.71.9.5560-5571.2005] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The failure to reduce the Campylobacter contamination of intensively reared poultry may be partially due to Campylobacter resisting disinfection in water after their internalization by waterborne protozoa. Campylobacter jejuni and a variety of waterborne protozoa, including ciliates, flagellates, and alveolates, were detected in the drinking water of intensively reared poultry by a combination of culture and molecular techniques. An in vitro assay showed that C. jejuni remained viable when internalized by Tetrahymena pyriformis and Acanthamoeba castellanii for significantly longer (up to 36 h) than when they were in purely a planktonic state. The internalized Campylobacter were also significantly more resistant to disinfection than planktonic organisms. Collectively, our results strongly suggest that protozoa in broiler drinking water systems can delay the decline of Campylobacter viability and increase Campylobacter disinfection resistance, thus increasing the potential of Campylobacter to colonize broilers.
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Affiliation(s)
- W J Snelling
- School of Biomedical Sciences, University of Ulster, Coleraine Campus, Cromore Road, Coleraine, Co. Londonderry, Northern Ireland, BT52 1SA
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45
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Ryan KA, Karim N, Worku M, Moore SA, Penn CW, O'Toole PW. HP0958 is an essential motility gene in Helicobacter pylori. FEMS Microbiol Lett 2005; 248:47-55. [PMID: 15946806 DOI: 10.1016/j.femsle.2005.05.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2005] [Revised: 05/13/2005] [Accepted: 05/13/2005] [Indexed: 11/17/2022] Open
Abstract
Motility is an essential colonization factor for the human gastric pathogen Helicobacter pylori. The H. pylori genome encodes most known flagellar proteins, although a number of key transcription regulators, chaperones, and structural proteins have not yet been identified. Using recently published yeast two-hybrid data we identified HP0958 as a potential motility-associated protein due to its strong interactions with RpoN (sigma(54)) and FliH, a flagellar ATPase regulator. HP0958 exhibits no sequence similarity to any published flagellar genes but contains a carboxy-terminal zinc finger domain that could function in nucleic acid or protein binding. We created a HP0958 mutant by inserting a chloramphenicol resistance marker into the gene using a PCR-based allelic exchange method and the resultant mutant was non-motile as measured by a BacTracker instrument. Electron microscopic analysis revealed that the HP0958 mutant cells were aflagellate and Western blot analysis revealed a dramatic reduction in flagellin and hook protein production. The HP0958 mutant also showed decreased transcription of flgE, flaB and flaA as well as the checkpoint genes flhA and flhF. Expression of flgM was increased relative to the wild-type and both rpoN and fliA (sigma(28)) expression were unchanged. We conclude that HP0958 is essential for normal motility and flagella production, and represents a novel flagellar component in the epsilon proteobacteria.
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Affiliation(s)
- Kieran A Ryan
- Department of Microbiology, Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
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Snelling WJ, Moore JE, McKenna JP, Lecky DM, Dooley JSG. Bacterial-protozoa interactions; an update on the role these phenomena play towards human illness. Microbes Infect 2005; 8:578-87. [PMID: 16298155 DOI: 10.1016/j.micinf.2005.09.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Revised: 08/05/2005] [Accepted: 08/08/2005] [Indexed: 11/22/2022]
Abstract
The usage of water with poor microbiological quality increases the risk of human illness. This review discusses and updates current thinking on the nature of the interaction between a range of human bacterial pathogens and waterborne protozoa. The importance of protozoa acting as protective environments for pathogenic bacteria from disinfection and of promoting extended survival in otherwise hostile environments is highlighted. The significance of biofilms in water systems, and new relationships between Salmonella and Campylobacter and water-borne protozoa are also discussed. The protection of pathogenic bacteria from disinfection within protozoa and/or biofilms has important implications for water safety.
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Affiliation(s)
- William J Snelling
- School of Biomedical Sciences, University of Ulster, Coleraine, Co., Londonderry, Northern Ireland BT52 1SA, UK.
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Ryan KA, Karim N, Worku M, Penn CW, O'Toole PW. Helicobacter pylori flagellar hook-filament transition is controlled by a FliK functional homolog encoded by the gene HP0906. J Bacteriol 2005; 187:5742-50. [PMID: 16077121 PMCID: PMC1196087 DOI: 10.1128/jb.187.16.5742-5750.2005] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Helicobacter pylori is a human gastric pathogen which is dependent on motility for infection. The H. pylori genome encodes a near-complete complement of flagellar proteins compared to model enteric bacteria. One of the few flagellar genes not annotated in H. pylori is that encoding FliK, a hook length control protein whose absence leads to a polyhook phenotype in Salmonella enterica. We investigated the role of the H. pylori gene HP0906 in flagellar biogenesis because of linkage to other flagellar genes, because of its transcriptional regulation pattern, and because of the properties of an ortholog in Campylobacter jejuni (N. Kamal and C. W. Penn, unpublished data). A nonpolar mutation of HP0906 in strain CCUG 17874 was generated by insertion of a chloramphenicol resistance marker. Cells of the mutant were almost completely nonmotile but produced sheathed, undulating polyhook structures at the cell pole. Expression of HP0906 in a Salmonella fliK mutant restored motility, confirming that HP0906 is the H. pylori fliK gene. Mutation of HP0906 caused a dramatic reduction in H. pylori flagellin protein production and a significant increase in production of the hook protein FlgE. The HP0906 mutant showed increased transcription of the flgE and flaB genes relative to the wild type, down-regulation of flaA transcription, and no significant change in transcription of the flagellar intermediate class genes flgM, fliD, and flhA. We conclude that the H. pylori HP0906 gene product is the hook length control protein FliK and that its function is required for turning off the sigma(54) regulon during progression of the flagellar gene expression cascade.
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Affiliation(s)
- Kieran A Ryan
- Department of Microbiology and Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
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Jiménez-Pearson MA, Dietz P, Beier D. Protein-protein interaction of HP137 with histidine kinase HP244 does not contribute to flagellar regulation in Helicobacter pylori. Microbiol Res 2005; 160:299-305. [PMID: 16035242 DOI: 10.1016/j.micres.2005.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Flagellar motility is essential for the ability of Helicobacter pylori to colonize the gastric mucosa. Expression of the flagella is controlled by a complex regulatory cascade involving the two-component system FlgR-HP244, the sigma factors sigma54 and sigma28 and the anti-sigma28 factor FlgM. The protein-protein interaction map of H. pylori, which is based on a high-throughput two-hybrid screen (Rain et al., 2001. Nature 409, 211-215) indicated a protein-protein interaction between the gene product of ORF hp137 and both the histidine kinase HP244 and the flagellar hook protein HP908. We hypothesized that HP137 might be involved in a feedback regulatory mechanism controlling the activity of histidine kinase HP244. Here we demonstrate that HP137 does not participate in the regulation of flagellar gene expression, neither in H. pylori nor in the closely related bacterium Campylobacter jejuni.
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Affiliation(s)
- Maria-Antonieta Jiménez-Pearson
- Theodor-Boveri-Institut für Biowissenschaften, Universität Würzburg, Lehrstuhl für Mikrobiologie, Am Hubland, D-97074 Würzburg, Germany
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49
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Ernst FD, Bereswill S, Waidner B, Stoof J, Mäder U, Kusters JG, Kuipers EJ, Kist M, van Vliet AHM, Homuth G. Transcriptional profiling of Helicobacter pylori Fur- and iron-regulated gene expression. MICROBIOLOGY-SGM 2005; 151:533-546. [PMID: 15699202 DOI: 10.1099/mic.0.27404-0] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Intracellular iron homeostasis is a necessity for almost all living organisms, since both iron restriction and iron overload can result in cell death. The ferric uptake regulator protein, Fur, controls iron homeostasis in most Gram-negative bacteria. In the human gastric pathogen Helicobacter pylori, Fur is thought to have acquired extra functions to compensate for the relative paucity of regulatory genes. To identify H. pylori genes regulated by iron and Fur, we used DNA array-based transcriptional profiling with RNA isolated from H. pylori 26695 wild-type and fur mutant cells grown in iron-restricted and iron-replete conditions. Sixteen genes encoding proteins involved in metal metabolism, nitrogen metabolism, motility, cell wall synthesis and cofactor synthesis displayed iron-dependent Fur-repressed expression. Conversely, 16 genes encoding proteins involved in iron storage, respiration, energy metabolism, chemotaxis, and oxygen scavenging displayed iron-induced Fur-dependent expression. Several Fur-regulated genes have been previously shown to be essential for acid resistance or gastric colonization in animal models, such as those encoding the hydrogenase and superoxide dismutase enzymes. Overall, there was a partial overlap between the sets of genes regulated by Fur and those previously identified as growth-phase, iron or acid regulated. Regulatory patterns were confirmed for five selected genes using Northern hybridization. In conclusion, H. pylori Fur is a versatile regulator involved in many pathways essential for gastric colonization. These findings further delineate the central role of Fur in regulating the unique capacity of H. pylori to colonize the human stomach.
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Affiliation(s)
- Florian D Ernst
- Institut für Mikrobiologie und Molekularbiologie, Ernst-Moritz-Arndt-Universität Greifswald, D-17487 Greifswald, Germany
- Department of Microbiology and Hygiene, Institute of Medical Microbiology and Hygiene, University Hospital of Freiburg, D-79140 Freiburg, Germany
- Department of Gastroenterology and Hepatology, Erasmus MC - University Medical Center Rotterdam, Dijkzigt L-455, Dr. Molewaterplein 40, 3015 GD Rotterdam, The Netherlands
| | - Stefan Bereswill
- Department of Microbiology and Hygiene, Institute of Medical Microbiology and Hygiene, University Hospital of Freiburg, D-79140 Freiburg, Germany
| | - Barbara Waidner
- Department of Microbiology and Hygiene, Institute of Medical Microbiology and Hygiene, University Hospital of Freiburg, D-79140 Freiburg, Germany
| | - Jeroen Stoof
- Department of Gastroenterology and Hepatology, Erasmus MC - University Medical Center Rotterdam, Dijkzigt L-455, Dr. Molewaterplein 40, 3015 GD Rotterdam, The Netherlands
| | - Ulrike Mäder
- Institut für Mikrobiologie und Molekularbiologie, Ernst-Moritz-Arndt-Universität Greifswald, D-17487 Greifswald, Germany
| | - Johannes G Kusters
- Department of Gastroenterology and Hepatology, Erasmus MC - University Medical Center Rotterdam, Dijkzigt L-455, Dr. Molewaterplein 40, 3015 GD Rotterdam, The Netherlands
| | - Ernst J Kuipers
- Department of Gastroenterology and Hepatology, Erasmus MC - University Medical Center Rotterdam, Dijkzigt L-455, Dr. Molewaterplein 40, 3015 GD Rotterdam, The Netherlands
| | - Manfred Kist
- Department of Microbiology and Hygiene, Institute of Medical Microbiology and Hygiene, University Hospital of Freiburg, D-79140 Freiburg, Germany
| | - Arnoud H M van Vliet
- Department of Gastroenterology and Hepatology, Erasmus MC - University Medical Center Rotterdam, Dijkzigt L-455, Dr. Molewaterplein 40, 3015 GD Rotterdam, The Netherlands
| | - Georg Homuth
- Institut für Mikrobiologie und Molekularbiologie, Ernst-Moritz-Arndt-Universität Greifswald, D-17487 Greifswald, Germany
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McGee DJ, Langford ML, Watson EL, Carter JE, Chen YT, Ottemann KM. Colonization and inflammation deficiencies in Mongolian gerbils infected by Helicobacter pylori chemotaxis mutants. Infect Immun 2005; 73:1820-7. [PMID: 15731083 PMCID: PMC1064941 DOI: 10.1128/iai.73.3.1820-1827.2005] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Helicobacter pylori causes disease in the human stomach and in mouse and gerbil stomach models. Previous results have shown that motility is critical for H. pylori to colonize mice, gerbils, and other animal models. The role of chemotaxis, however, in colonization and disease is less well understood. Two genes in the H. pylori chemotaxis pathway, cheY and tlpB, which encode the chemotaxis response regulator and a methyl-accepting chemoreceptor, respectively, were disrupted. The cheY mutation was complemented with a wild-type copy of cheY inserted into the chromosomal rdxA gene. The cheY mutant lost chemotaxis but retained motility, while all other strains were motile and chemotactic in vitro. These strains were inoculated into gerbils either alone or in combination with the wild-type strain, and colonization and inflammation were assessed. While the cheY mutant completely failed to colonize gerbil stomachs, the tlpB mutant colonized at levels similar to those of the wild type. With the tlpB mutant, there was a substantial decrease in inflammation in the gerbil stomach compared to that with the wild type. Furthermore, there were differences in the numbers of each immune cell in the tlpB-mutant-infected stomach: the ratio of lymphocytes to neutrophils was about 8 to 1 in the wild type but only about 1 to 1 in the mutant. These results suggest that the TlpB chemoreceptor plays an important role in the inflammatory response while the CheY chemotaxis regulator plays a critical role in initial colonization. Chemotaxis mutants may provide new insights into the steps involved in H. pylori pathogenesis.
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Affiliation(s)
- David J McGee
- Department of Microbiology & Immunology, University of South Alabama College of Medicine, 307 N. University Blvd., Mobile, AL 36688, USA.
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