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Saberi S, Shans N, Ghaffari S, Esmaeili M, Mohammadi M. The role of CEACAMs versus integrins in Helicobacter pylori CagA translocation: a systematic review. Microbes Infect 2024; 26:105246. [PMID: 37926369 DOI: 10.1016/j.micinf.2023.105246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 10/24/2023] [Accepted: 10/30/2023] [Indexed: 11/07/2023]
Abstract
The delivery of Helicobacter pylori CagA into host cells was long believed to occur through the integrin cell surface receptors. However, the role of CEACAM receptors has recently been highlighted, instead. Here, we have categorized the existing experimental evidence according to whether deletion, upregulation, downregulation, or inhibition of the target ligands (T4SS or HopQ) or receptors (integrins or CEACAMs), result in alterations in CagA phosphorylation, cell elongation, or IL-8 production. According to our analysis, the statistics favor the essence of most of the T4SS constituents and the involvement of HopQ adhesin in all three functions. Concerning the integrin family, the collected data is controversial, but yielding towards it being dispensable or involved in CagA translocation. Yet, regarding cell elongation, more events are showing β1 integrin being involved, than αvβ4 being inhibitory. Concerning IL-8 secretion, again there are more events showing α5, β1 and β6 integrins to be involved, than those showing inhibitory roles for β1, β4 and β6 integrins. Finally, CEACAM 1, 3, and 5 are identified as mostly essential or involved in CagA phosphorylation, whereasCEACAM 4, 7, and 8 are found dispensable and CEACAM6 is under debate. Conversely, CEACAM1, 5 and 6 appear mostly dispensable for cell elongation. Noteworthy is the choice of cell type, bacterial strain, multiplicity and duration of infection, as well as the sensitivity of the detection methods, all of which can affect the variably obtained results.
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Affiliation(s)
- Samaneh Saberi
- HPGC Research Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Nazanin Shans
- HPGC Research Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Saba Ghaffari
- HPGC Research Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Maryam Esmaeili
- HPGC Research Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Marjan Mohammadi
- HPGC Research Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran.
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2
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Tran SC, Bryant KN, Cover TL. The Helicobacter pylori cag pathogenicity island as a determinant of gastric cancer risk. Gut Microbes 2024; 16:2314201. [PMID: 38391242 PMCID: PMC10896142 DOI: 10.1080/19490976.2024.2314201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Accepted: 01/31/2024] [Indexed: 02/24/2024] Open
Abstract
Helicobacter pylori strains can be broadly classified into two groups based on whether they contain or lack a chromosomal region known as the cag pathogenicity island (cag PAI). Colonization of the human stomach with cag PAI-positive strains is associated with an increased risk of gastric cancer and peptic ulcer disease, compared to colonization with cag PAI-negative strains. The cag PAI encodes a secreted effector protein (CagA) and components of a type IV secretion system (Cag T4SS) that delivers CagA and non-protein substrates into host cells. Animal model experiments indicate that CagA and the Cag T4SS stimulate a gastric mucosal inflammatory response and contribute to the development of gastric cancer. In this review, we discuss recent studies defining structural and functional features of CagA and the Cag T4SS and mechanisms by which H. pylori strains containing the cag PAI promote the development of gastric cancer and peptic ulcer disease.
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Affiliation(s)
- Sirena C Tran
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Kaeli N Bryant
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Timothy L Cover
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN, USA
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3
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Ryan ME, Damke PP, Bryant C, Sheedlo MJ, Shaffer CL. Architectural asymmetry enables DNA transport through the Helicobacter pylori cag type IV secretion system. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.25.550604. [PMID: 37546756 PMCID: PMC10402047 DOI: 10.1101/2023.07.25.550604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Structural asymmetry within secretion system architecture is fundamentally important for apparatus diversification and biological function. However, the mechanism by which symmetry mismatch contributes to nanomachine assembly and interkingdom effector translocation are undefined. Here, we show that architectural asymmetry orchestrates dynamic substrate selection and enables trans-kingdom DNA conjugation through the Helicobacter pylori cag type IV secretion system (cag T4SS). Structural analyses of asymmetric units within the cag T4SS periplasmic ring complex (PRC) revealed intermolecular π-π stacking interactions that coordinate DNA binding and license trans-kingdom conjugation without disrupting the translocation of protein and peptidoglycan effector molecules. Additionally, we identified a novel proximal translocation channel gating mechanism that regulates cargo loading and governs substrate transport across the outer membrane. We thus propose a model whereby the organization and geometry of architectural symmetry mismatch exposes π-π interfaces within the PRC to facilitate DNA transit through the cag T4SS translocation channel.
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Affiliation(s)
- Mackenzie E. Ryan
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, 40506, USA
| | - Prashant P. Damke
- Department of Veterinary Sciences, University of Kentucky College of Agriculture, Lexington, KY, 40546, USA
| | - Caitlynn Bryant
- Department of Veterinary Sciences, University of Kentucky College of Agriculture, Lexington, KY, 40546, USA
| | - Michael J. Sheedlo
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Carrie L. Shaffer
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, 40506, USA
- Department of Veterinary Sciences, University of Kentucky College of Agriculture, Lexington, KY, 40546, USA
- Department of Pharmaceutical Sciences, University of Kentucky College of Pharmacy, Lexington, KY, 40536, USA
- Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY, 40506, USA
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4
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Azizimoghaddam Y, Kermanpour S, Mirzaei N, Houri H, Nabavi-Rad A, Asadzadeh Aghdaei H, Yadegar A, Zali MR. Genetic diversity of Helicobacter pylori type IV secretion system cagI and cagN genes and their association with clinical diseases. Sci Rep 2023; 13:10264. [PMID: 37355714 PMCID: PMC10290643 DOI: 10.1038/s41598-023-37392-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 06/21/2023] [Indexed: 06/26/2023] Open
Abstract
A number of cagPAI genes in the Helicobacter pylori genome are considered the most evolved genes under a diversifying selection and evolutionary pressure. Among them, cagI and cagN are described as a part of the two different-operon of cagPAI that are involved in the T4SS machinery, but the definite association of these factors with clinical manifestations is still unclear. A total of 70 H. pylori isolates were obtained from different gastroduodenal patients. All isolates were examined for the presence of primary H. pylori virulence genes by PCR analysis. Direct DNA sequence analysis was performed for the cagI and cagN genes. The results were compared with the reference strain. The cagI, cagN, cagA, cagL, vacA s1m1, vacA s1m2, vacA s2m2, babA2, sabA, and dupA genotypes were detected in 80, 91.4, 84, 91.4, 32.8, 42.8, 24.4, 97.1, 84.3, and 84.3% of the total isolates, respectively. The most variable codon usage in cagI was observed at residues 20-25, 55-60, 94, 181-199, 213-221, 241-268, and 319-320, while the most variable codon usage in CagN hypervariable motif (CagNHM) was observed at residues 53 to 63. Sequencing data analysis of cagN revealed a hypothetical hexapeptide motif (EAKDEN/K) in residues of 278-283 among six H. pylori isolates, which needs further studies to evaluate its putative function. The present study demonstrated a high prevalence of cagI and cagN genes among Iranian H. pylori isolates with gastroduodenal diseases. Furthermore, no significant correlation between cagI and cagN variants and clinical diseases was observed in the present study. However, all patients had a high prevalence of cagPAI genes including cagI, cagN, cagA, and cagL, which indicates more potential role of these genes in disease outcome.
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Affiliation(s)
- Yasaman Azizimoghaddam
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sadaf Kermanpour
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Nasrin Mirzaei
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hamidreza Houri
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ali Nabavi-Rad
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hamid Asadzadeh Aghdaei
- Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Abbas Yadegar
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Mohammad Reza Zali
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Gupta N, Kumar A, Verma VK. Strategies adopted by gastric pathogen Helicobacter pylori for a mature biofilm formation: Antimicrobial peptides as a visionary treatment. Microbiol Res 2023; 273:127417. [PMID: 37267815 DOI: 10.1016/j.micres.2023.127417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 05/15/2023] [Accepted: 05/21/2023] [Indexed: 06/04/2023]
Abstract
Enormous efforts in recent past two decades to eradicate the pathogen that has been prevalent in half of the world's population have been problematic. The biofilm formed by Helicobacter pylori provides resistance towards innate immune cells, various combinatorial antibiotics, and human antimicrobial peptides, despite the fact that these all are potent enough to eradicate it in vitro. Biofilm provides the opportunity to secrete various virulence factors that strengthen the interaction between host and pathogen helping in evading the innate immune system and ultimately leading to persistence. To our knowledge, this review is the first of its kind to explain briefly the journey of H. pylori starting with the chemotaxis, the mechanism for selecting the site for colonization, the stress faced by the pathogen, and various adaptations to evade these stress conditions by forming biofilm and the morphological changes acquired by the pathogen in mature biofilm. Furthermore, we have explained the human GI tract antimicrobial peptides and the reason behind the failure of these AMPs, and how encapsulation of Pexiganan-A(MSI-78A) in a chitosan microsphere increases the efficiency of eradication.
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Affiliation(s)
- Nidhi Gupta
- Department of Microbiology, University of Delhi South Campus, Benito Juarez Marg, New Delhi 110021, India.
| | - Atul Kumar
- Department of Microbiology, University of Delhi South Campus, Benito Juarez Marg, New Delhi 110021, India
| | - Vijay Kumar Verma
- Department of Microbiology, University of Delhi South Campus, Benito Juarez Marg, New Delhi 110021, India.
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6
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Blanc M, Lettl C, Guérin J, Vieille A, Furler S, Briand-Schumacher S, Dreier B, Bergé C, Plückthun A, Vadon-Le Goff S, Fronzes R, Rousselle P, Fischer W, Terradot L. Designed Ankyrin Repeat Proteins provide insights into the structure and function of CagI and are potent inhibitors of CagA translocation by the Helicobacter pylori type IV secretion system. PLoS Pathog 2023; 19:e1011368. [PMID: 37155700 DOI: 10.1371/journal.ppat.1011368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 05/18/2023] [Accepted: 04/18/2023] [Indexed: 05/10/2023] Open
Abstract
The bacterial human pathogen Helicobacter pylori produces a type IV secretion system (cagT4SS) to inject the oncoprotein CagA into gastric cells. The cagT4SS external pilus mediates attachment of the apparatus to the target cell and the delivery of CagA. While the composition of the pilus is unclear, CagI is present at the surface of the bacterium and required for pilus formation. Here, we have investigated the properties of CagI by an integrative structural biology approach. Using Alpha Fold 2 and Small Angle X-ray scattering, it was found that CagI forms elongated dimers mediated by rod-shape N-terminal domains (CagIN) prolonged by globular C-terminal domains (CagIC). Three Designed Ankyrin Repeat Proteins (DARPins) K2, K5 and K8 selected against CagI interacted with CagIC with subnanomolar affinities. The crystal structures of the CagI:K2 and CagI:K5 complexes were solved and identified the interfaces between the molecules, thereby providing a structural explanation for the difference in affinity between the two binders. Purified CagI and CagIC were found to interact with adenocarcinoma gastric (AGS) cells, induced cell spreading and the interaction was inhibited by K2. The same DARPin inhibited CagA translocation by up to 65% in AGS cells while inhibition levels were 40% and 30% with K8 and K5, respectively. Our study suggests that CagIC plays a key role in cagT4SS-mediated CagA translocation and that DARPins targeting CagI represent potent inhibitors of the cagT4SS, a crucial risk factor for gastric cancer development.
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Affiliation(s)
- Marine Blanc
- UMR 5086 Molecular Microbiology and Structural Biochemistry CNRS-Université de Lyon, Institut de Biologie et Chimie des Protéines, Lyon, France
| | - Clara Lettl
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Jérémy Guérin
- UMR 5086 Molecular Microbiology and Structural Biochemistry CNRS-Université de Lyon, Institut de Biologie et Chimie des Protéines, Lyon, France
| | - Anaïs Vieille
- UMR 5086 Molecular Microbiology and Structural Biochemistry CNRS-Université de Lyon, Institut de Biologie et Chimie des Protéines, Lyon, France
| | - Sven Furler
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | | | - Birgit Dreier
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Célia Bergé
- UMR 5086 Molecular Microbiology and Structural Biochemistry CNRS-Université de Lyon, Institut de Biologie et Chimie des Protéines, Lyon, France
| | - Andreas Plückthun
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Sandrine Vadon-Le Goff
- University of Lyon, CNRS UMR5305, Tissue Biology and Therapeutic Engineering Laboratory (LBTI), Lyon, France
| | - Rémi Fronzes
- European Institute of Chemistry and Biology, CNRS UMR 5234 Microbiologie Fondamentale et Pathogénicité, Univ. Bordeaux, Pessac, France
| | - Patricia Rousselle
- University of Lyon, CNRS UMR5305, Tissue Biology and Therapeutic Engineering Laboratory (LBTI), Lyon, France
| | - Wolfgang Fischer
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Laurent Terradot
- UMR 5086 Molecular Microbiology and Structural Biochemistry CNRS-Université de Lyon, Institut de Biologie et Chimie des Protéines, Lyon, France
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7
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Xi Y, Zhang XL, Luo QX, Gan HN, Liu YS, Shao SH, Mao XH. Helicobacter pylori regulates stomach diseases by activating cell pathways and DNA methylation of host cells. Front Cell Dev Biol 2023; 11:1187638. [PMID: 37215092 PMCID: PMC10192871 DOI: 10.3389/fcell.2023.1187638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 04/25/2023] [Indexed: 05/24/2023] Open
Abstract
One of the most prevalent malignant tumors of the digestive tract is gastric cancer (GC). Age, high salt intake, Helicobacter pylori (H. pylori) infection, and a diet deficient in fruits and vegetables are risk factors for the illness. A significant risk factor for gastric cancer is infection with H. pylori. Infecting gastric epithelial cells with virulence agents secreted by H. pylori can cause methylation of tumor genes or carcinogenic signaling pathways to be activated. Regulate downstream genes' aberrant expression, albeit the precise mechanism by which this happens is unclear. Oncogene, oncosuppressor, and other gene modifications, as well as a number of different gene change types, are all directly associated to the carcinogenesis of gastric cancer. In this review, we describe comprehensive H. pylori and its virulence factors, as well as the activation of the NF-κB, MAPK, JAK/STAT signaling pathways, and DNA methylation following infection with host cells via virulence factors, resulting in abnormal gene expression. As a result, host-related proteins are regulated, and gastric cancer progression is influenced. This review provides insight into the H. pylori infection, summarizes a series of relevant papers, discusses the complex signaling pathways underlying molecular mechanisms, and proposes new approach to immunotherapy of this important disease.
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Affiliation(s)
- Yue Xi
- School of Medicine, Jiangsu University, Zhenjiang, China
| | - Xiao-Li Zhang
- Department of Clinical Laboratory, The Affiliated Yixing Hospital of Jiangsu University, Wuxi, China
| | - Qing-Xin Luo
- School of Medicine, Jiangsu University, Zhenjiang, China
| | - Hai-Ning Gan
- School of Medicine, Jiangsu University, Zhenjiang, China
| | - Yu-Shi Liu
- School of Medicine, Jiangsu University, Zhenjiang, China
| | - Shi-He Shao
- School of Medicine, Jiangsu University, Zhenjiang, China
| | - Xu-Hua Mao
- Department of Clinical Laboratory, The Affiliated Yixing Hospital of Jiangsu University, Wuxi, China
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8
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Wroblewski LE, Peek RM. Clinical Pathogenesis, Molecular Mechanisms of Gastric Cancer Development. Curr Top Microbiol Immunol 2023; 444:25-52. [PMID: 38231214 PMCID: PMC10924282 DOI: 10.1007/978-3-031-47331-9_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
The human pathogen Helicobacter pylori is the strongest known risk factor for gastric disease and cancer, and gastric cancer remains a leading cause of cancer-related death across the globe. Carcinogenic mechanisms associated with H. pylori are multifactorial and are driven by bacterial virulence constituents, host immune responses, environmental factors such as iron and salt, and the microbiota. Infection with strains that harbor the cytotoxin-associated genes (cag) pathogenicity island, which encodes a type IV secretion system (T4SS) confer increased risk for developing more severe gastric diseases. Other important H. pylori virulence factors that augment disease progression include vacuolating cytotoxin A (VacA), specifically type s1m1 vacA alleles, serine protease HtrA, and the outer-membrane adhesins HopQ, BabA, SabA and OipA. Additional risk factors for gastric cancer include dietary factors such as diets that are high in salt or low in iron, H. pylori-induced perturbations of the gastric microbiome, host genetic polymorphisms, and infection with Epstein-Barr virus. This chapter discusses in detail host factors and how H. pylori virulence factors augment the risk of developing gastric cancer in human patients as well as how the Mongolian gerbil model has been used to define mechanisms of H. pylori-induced inflammation and cancer.
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Affiliation(s)
- Lydia E Wroblewski
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Richard M Peek
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
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9
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Discovery of a Novel Inner Membrane-Associated Bacterial Structure Related to the Flagellar Type III Secretion System. J Bacteriol 2022; 204:e0014422. [PMID: 35862756 PMCID: PMC9380563 DOI: 10.1128/jb.00144-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The bacterial flagellar type III secretion system (fT3SS) is a suite of membrane-embedded and cytoplasmic proteins responsible for building the flagellar motility machinery. Homologous nonflagellar (NF-T3SS) proteins form the injectisome machinery that bacteria use to deliver effector proteins into eukaryotic cells, and other family members were recently reported to be involved in the formation of membrane nanotubes. Here, we describe a novel, evolutionarily widespread, hat-shaped structure embedded in the inner membranes of bacteria, of yet-unidentified function, that is present in species containing fT3SS. Mutant analysis suggests a relationship between this novel structure and the fT3SS, but not the NF-T3SS. While the function of this novel structure remains unknown, we hypothesize that either some of the fT3SS proteins assemble within the hat-like structure, perhaps including the fT3SS core complex, or that fT3SS components regulate other proteins that form part of this novel structure. IMPORTANCE The type III secretion system (T3SS) is a fascinating suite of proteins involved in building diverse macromolecular systems, including the bacterial flagellar motility machine, the injectisome machinery that bacteria use to inject effector proteins into host cells, and probably membrane nanotubes which connect bacterial cells. Here, we accidentally discovered a novel inner membrane-associated complex related to the flagellar T3SS. Examining our lab database, which is comprised of more than 40,000 cryo-tomograms of dozens of species, we discovered that this novel structure is both ubiquitous and ancient, being present in highly divergent classes of bacteria. Discovering a novel, widespread structure related to what are among the best-studied molecular machines in bacteria will open new venues for research aiming at understanding the function and evolution of T3SS proteins.
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10
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Kaplan M, Oikonomou CM, Wood CR, Chreifi G, Subramanian P, Ortega DR, Chang Y, Beeby M, Shaffer CL, Jensen GJ. Novel transient cytoplasmic rings stabilize assembling bacterial flagellar motors. EMBO J 2022; 41:e109523. [PMID: 35301732 PMCID: PMC9108667 DOI: 10.15252/embj.2021109523] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 01/31/2022] [Accepted: 02/16/2022] [Indexed: 12/20/2022] Open
Abstract
The process by which bacterial cells build their intricate flagellar motility apparatuses has long fascinated scientists. Our understanding of this process comes mainly from studies of purified flagella from two species, Escherichia coli and Salmonella enterica. Here, we used electron cryo-tomography (cryo-ET) to image the assembly of the flagellar motor in situ in diverse Proteobacteria: Hylemonella gracilis, Helicobacter pylori, Campylobacter jejuni, Pseudomonas aeruginosa, Pseudomonas fluorescens, and Shewanella oneidensis. Our results reveal the in situ structures of flagellar intermediates, beginning with the earliest flagellar type III secretion system core complex (fT3SScc) and MS-ring. In high-torque motors of Beta-, Gamma-, and Epsilon-proteobacteria, we discovered novel cytoplasmic rings that interact with the cytoplasmic torque ring formed by FliG. These rings, associated with the MS-ring, assemble very early and persist until the stators are recruited into their periplasmic ring; in their absence the stator ring does not assemble. By imaging mutants in Helicobacter pylori, we found that the fT3SScc proteins FliO and FliQ are required for the assembly of these novel cytoplasmic rings. Our results show that rather than a simple accretion of components, flagellar motor assembly is a dynamic process in which accessory components interact transiently to assist in building the complex nanomachine.
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Affiliation(s)
- Mohammed Kaplan
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Catherine M Oikonomou
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Cecily R Wood
- Department of Veterinary ScienceUniversity of KentuckyLexingtonKYUSA
| | - Georges Chreifi
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Poorna Subramanian
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Davi R Ortega
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Yi‐Wei Chang
- Department of Biochemistry and BiophysicsPerelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPAUSA
| | - Morgan Beeby
- Department of Life SciencesImperial College LondonLondonUK
| | - Carrie L Shaffer
- Department of Veterinary ScienceUniversity of KentuckyLexingtonKYUSA
- Department of Microbiology, Immunology, and Molecular GeneticsUniversity of KentuckyLexingtonKYUSA
- Department of Pharmaceutical SciencesUniversity of KentuckyLexingtonKYUSA
| | - Grant J Jensen
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
- Department of Chemistry and BiochemistryBrigham Young UniversityProvoUTUSA
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11
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Liu X, Khara P, Baker ML, Christie PJ, Hu B. Structure of a type IV secretion system core complex encoded by multi-drug resistance F plasmids. Nat Commun 2022; 13:379. [PMID: 35046412 PMCID: PMC8770708 DOI: 10.1038/s41467-022-28058-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Accepted: 01/04/2022] [Indexed: 11/09/2022] Open
Abstract
Bacterial type IV secretion systems (T4SSs) are largely responsible for the proliferation of multi-drug resistance. We solved the structure of the outer-membrane core complex (OMCCF) of a T4SS encoded by a conjugative F plasmid at <3.0 Å resolution by cryoelectron microscopy. The OMCCF consists of a 13-fold symmetrical outer ring complex (ORC) built from 26 copies of TraK and TraV C-terminal domains, and a 17-fold symmetrical central cone (CC) composed of 17 copies of TraB β-barrels. Domains of TraV and TraB also bind the CC and ORC substructures, establishing that these proteins undergo an intraprotein symmetry alteration to accommodate the C13:C17 symmetry mismatch. We present evidence that other pED208-encoded factors stabilize the C13:C17 architecture and define the importance of TraK, TraV and TraB domains to T4SSF function. This work identifies OMCCF structural motifs of proposed importance for structural transitions associated with F plasmid dissemination and F pilus biogenesis.
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Affiliation(s)
- Xiangan Liu
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, TX, 77030, USA
| | - Pratick Khara
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, TX, 77030, USA
| | - Matthew L Baker
- Department of Biochemistry and Molecular Biology, McGovern Medical School, 6431 Fannin St, Houston, TX, 77030, USA
| | - Peter J Christie
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, TX, 77030, USA.
| | - Bo Hu
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, TX, 77030, USA.
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12
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Ray AK, Luis PB, Mishra SK, Barry DP, Asim M, Pandey A, Chaturvedi M, Gupta J, Gupta S, Mahant S, Das R, Kumar P, Shalimar, Wilson KT, Schneider C, Chaturvedi R. Curcumin Oxidation Is Required for Inhibition of Helicobacter pylori Growth, Translocation and Phosphorylation of Cag A. Front Cell Infect Microbiol 2022; 11:765842. [PMID: 35004346 PMCID: PMC8740292 DOI: 10.3389/fcimb.2021.765842] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 12/02/2021] [Indexed: 01/22/2023] Open
Abstract
Curcumin is a potential natural remedy for preventing Helicobacter pylori-associated gastric inflammation and cancer. Here, we analyzed the effect of a phospholipid formulation of curcumin on H. pylori growth, translocation and phosphorylation of the virulence factor CagA and host protein kinase Src in vitro and in an in vivo mouse model of H. pylori infection. Growth of H. pylori was inhibited dose-dependently by curcumin in vitro. H. pylori was unable to metabolically reduce curcumin, whereas two enterobacteria, E. coli and Citrobacter rodentium, which efficiently reduced curcumin to the tetra- and hexahydro metabolites, evaded growth inhibition. Oxidative metabolism of curcumin was required for the growth inhibition of H. pylori and the translocation and phosphorylation of CagA and cSrc, since acetal- and diacetal-curcumin that do not undergo oxidative transformation were ineffective. Curcumin attenuated mRNA expression of the H. pylori virulence genes cagE and cagF in a dose-dependent manner and inhibited translocation and phosphorylation of CagA in gastric epithelial cells. H. pylori strains isolated from dietary curcumin-treated mice showed attenuated ability to induce cSrc phosphorylation and the mRNA expression of the gene encoding for IL-8, suggesting long-lasting effects of curcumin on the virulence of H. pylori. Our work provides mechanistic evidence that encourages testing of curcumin as a dietary approach to inhibit the virulence of CagA.
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Affiliation(s)
- Ashwini Kumar Ray
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, India.,Department of Microbiology, Saheed Rajguru College of Applied Sciences for Women, University of Delhi, New Delhi, India.,Department of Environmental Studies, University of Delhi, New Delhi, India
| | - Paula B Luis
- Department of Pharmacology and Vanderbilt Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, TN, United States
| | | | - Daniel P Barry
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Mohammad Asim
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Achyut Pandey
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Maya Chaturvedi
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Jyoti Gupta
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Shilpi Gupta
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Shweta Mahant
- Centre for Medical Biotechnology, Amity Institute of Biotechnology, Amity University, Noida, India
| | - Rajashree Das
- Centre for Medical Biotechnology, Amity Institute of Biotechnology, Amity University, Noida, India
| | - Pramod Kumar
- Department of Chemistry, Sri Aurobindo College, University of Delhi, New Delhi, India
| | - Shalimar
- Department of Gastroenterology and Human Nutrition Unit, All India Institute of Medical Sciences, New Delhi, India
| | - Keith T Wilson
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States.,Center for Mucosal Inflammation and Cancer, Vanderbilt University Medical Center, Nashville, TN, United States.,Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN, United States
| | - Claus Schneider
- Department of Pharmacology and Vanderbilt Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Rupesh Chaturvedi
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
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13
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Jang S, Hansen LM, Su H, Solnick JV, Cha JH. Host immune response mediates changes in cagA copy number and virulence potential of Helicobacter pylori. Gut Microbes 2022; 14:2044721. [PMID: 35289715 PMCID: PMC8928821 DOI: 10.1080/19490976.2022.2044721] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 02/15/2022] [Indexed: 02/04/2023] Open
Abstract
Helicobacter pylori is the major risk factor for gastric cancer. H. pylori harboring the type IV secretion system (T4SS) and its effector CagA encoded on the cag pathogenicity Island (cagPAI) increases the risk. H. pylori PMSS1 has a multi-cagA genotype, modulating cagA copy number dynamically from zero to four copies. To examine the effect of the immune response on cagA copy number change, we utilized a mouse model with different immune status. PMSS1 recovered from Rag1-/- mice, lacking functional T or B cells, retained more cagA copies. PMSS1 recovered from Il10-/- mice, showing intense inflammation, had fewer cagA copies compared to those recovered from wild-type mice. Moreover, cagA copy number of PMSS1 recovered from wild-type and Il10-/- mice was positively correlated with the capacity to induce IL-8 secretion at four weeks of infection. Since recombination in cagY influences T4SS function, including CagA translocation and IL-8 induction, we constructed a multiple linear regression model to predict H. pylori-induced IL-8 expression based on cagA copy number and cagY recombination status; H. pylori induces more IL-8 secretion when the strain has more cagA copies and intact cagY. This study shows that H. pylori PMSS1 in mice with less intense immune response possess higher cagA copy number than those infected in mice with more intense immune response and thus the multi-cagA genotype, along with cagY recombination, functions as an immune-sensitive regulator of H. pylori virulence.
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Affiliation(s)
- Sungil Jang
- Department of Oral Biology, Oral Science Research Center, Department of Applied Life Science, The Graduate School, BK21 Four Project, Yonsei University College of Dentistry, Seoul, Republic of Korea
- Department of Oral Biochemistry, School of Dentistry, Jeonbuk National University, Jeonju, Republic of Korea
| | - Lori M. Hansen
- Center for Immunology and Infectious Diseases; Departments of Medicine and of Microbiology and Immunology, School of Medicine; University of California Davis, Davis, CA, USA
| | - Hanfu Su
- Affiliated Stomatology Hospital of Guangzhou Medical University, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Guangzhou, Guangdong, China
| | - Jay V. Solnick
- Center for Immunology and Infectious Diseases; Departments of Medicine and of Microbiology and Immunology, School of Medicine; University of California Davis, Davis, CA, USA
| | - Jeong-Heon Cha
- Department of Oral Biology, Oral Science Research Center, Department of Applied Life Science, The Graduate School, BK21 Four Project, Yonsei University College of Dentistry, Seoul, Republic of Korea
- Affiliated Stomatology Hospital of Guangzhou Medical University, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Guangzhou, Guangdong, China
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14
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Delineation of the pH-Responsive Regulon Controlled by the Helicobacter pylori ArsRS Two-Component System. Infect Immun 2021; 89:IAI.00597-20. [PMID: 33526561 DOI: 10.1128/iai.00597-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 01/09/2021] [Indexed: 12/22/2022] Open
Abstract
Helicobacter pylori encounters a wide range of pH within the human stomach. In a comparison of H. pylori cultured in vitro under neutral or acidic conditions, about 15% of genes are differentially expressed, and corresponding changes are detectable for many of the encoded proteins. The ArsRS two-component system (TCS), comprised of the sensor kinase ArsS and its cognate response regulator ArsR, has an important role in mediating pH-responsive changes in H. pylori gene expression. In this study, we sought to delineate the pH-responsive ArsRS regulon and further define the role of ArsR in pH-responsive gene expression. We compared H. pylori strains containing an intact ArsRS system with an arsS null mutant or strains containing site-specific mutations of a conserved aspartate residue (D52) in ArsR, which is phosphorylated in response to signals relayed by the cognate sensor kinase ArsS. We identified 178 genes that were pH-responsive in strains containing an intact ArsRS system but not in ΔarsS or arsR mutants. These constituents of the pH-responsive ArsRS regulon include genes involved in acid acclimatization (ureAB, amidases), oxidative stress responses (katA, sodB), transcriptional regulation related to iron or nickel homeostasis (fur, nikR), and genes encoding outer membrane proteins (including sabA, alpA, alpB, hopD [labA], and horA). When comparing H. pylori strains containing an intact ArsRS TCS with arsRS mutants, each cultured at neutral pH, relatively few genes are differentially expressed. Collectively, these data suggest that ArsRS-mediated gene regulation has an important role in H. pylori adaptation to changing pH conditions.
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15
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El Khadir M, Boukhris SA, Zahir SO, Benajah DA, Ibrahimi SA, Chbani L, El Abkari M, Bennani B. CagE, cagA and cagA 3' region polymorphism of Helicobacter pylori and their association with the intra-gastric diseases in Moroccan population. Diagn Microbiol Infect Dis 2021; 100:115372. [PMID: 33813354 DOI: 10.1016/j.diagmicrobio.2021.115372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 03/02/2021] [Accepted: 03/06/2021] [Indexed: 10/21/2022]
Abstract
Helicobacter pylori infection is the most important etiological factor in gastroduodenal diseases development. Its evolution is influenced by several factors, including bacterial virulence genes such as cagA and cagE. This work aimed to evaluate the predictive value of cagE alone and in combination with cagA and CagA-EPIYA-C motifs number as a marker of the infection evolution. A total of 823 H. pylori DNA extracted from biopsies of consenting patients suffering from gastritis, peptic ulcer, or gastric cancer. The cagE, cagA status and cagA 3' region polymorphism were determined by PCR. The analysis shows that the risk of duodenal ulcer is 1.97-fold higher (CI = 1.18-3.30) in patients infected by strains cagA+/cagE+. And the risk of gastric cancer is 5.19-fold higher (CI = 1.18-22.70) in patients harboring strains cagE+/2EPIYA-C. The results suggest that cagE in combination with cagA-EPIYA-C motifs number can be used as predictive biomarker of H. pylori infection evolution.
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Affiliation(s)
- Mounia El Khadir
- Laboratoire de Pathologie Humaine Biomédecine et Environnement, Equipe micro-organismes génomique et facteurs oncogènes, Faculté de médecine et de Pharmacie de Fès (FMPF), Université Sidi Mohammed Ben Abdellah (USMBA), Fès, Maroc.; Laboratoire de microbiologie et de Biologie Moléculaire, FMPF, USMBA
| | - Samia Alaoui Boukhris
- Laboratoire de Pathologie Humaine Biomédecine et Environnement, Equipe micro-organismes génomique et facteurs oncogènes, Faculté de médecine et de Pharmacie de Fès (FMPF), Université Sidi Mohammed Ben Abdellah (USMBA), Fès, Maroc.; Laboratoire de microbiologie et de Biologie Moléculaire, FMPF, USMBA
| | - Souad Oirdi Zahir
- Laboratoire de Pathologie Humaine Biomédecine et Environnement, Equipe micro-organismes génomique et facteurs oncogènes, Faculté de médecine et de Pharmacie de Fès (FMPF), Université Sidi Mohammed Ben Abdellah (USMBA), Fès, Maroc.; Laboratoire de microbiologie et de Biologie Moléculaire, FMPF, USMBA
| | - Dafr-Allah Benajah
- Laboratoire de Pathologie Humaine Biomédecine et Environnement, Equipe micro-organismes génomique et facteurs oncogènes, Faculté de médecine et de Pharmacie de Fès (FMPF), Université Sidi Mohammed Ben Abdellah (USMBA), Fès, Maroc.; Service d'Hépato gastro-entérologie CHU Hassan II, Fès, Maroc
| | - Sidi Adil Ibrahimi
- Laboratoire de Pathologie Humaine Biomédecine et Environnement, Equipe micro-organismes génomique et facteurs oncogènes, Faculté de médecine et de Pharmacie de Fès (FMPF), Université Sidi Mohammed Ben Abdellah (USMBA), Fès, Maroc.; Service d'Hépato gastro-entérologie CHU Hassan II, Fès, Maroc
| | - Laila Chbani
- Service d'Anatomie pathologique CHU Hassan II, Fès, Maroc
| | - Mohamed El Abkari
- Laboratoire de Pathologie Humaine Biomédecine et Environnement, Equipe micro-organismes génomique et facteurs oncogènes, Faculté de médecine et de Pharmacie de Fès (FMPF), Université Sidi Mohammed Ben Abdellah (USMBA), Fès, Maroc.; Service d'Hépato gastro-entérologie CHU Hassan II, Fès, Maroc
| | - Bahia Bennani
- Laboratoire de Pathologie Humaine Biomédecine et Environnement, Equipe micro-organismes génomique et facteurs oncogènes, Faculté de médecine et de Pharmacie de Fès (FMPF), Université Sidi Mohammed Ben Abdellah (USMBA), Fès, Maroc.; Laboratoire de microbiologie et de Biologie Moléculaire, FMPF, USMBA.
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16
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Costa TRD, Harb L, Khara P, Zeng L, Hu B, Christie PJ. Type IV secretion systems: Advances in structure, function, and activation. Mol Microbiol 2021; 115:436-452. [PMID: 33326642 DOI: 10.1111/mmi.14670] [Citation(s) in RCA: 105] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 12/12/2020] [Accepted: 12/13/2020] [Indexed: 12/14/2022]
Abstract
Bacterial type IV secretion systems (T4SSs) are a functionally diverse translocation superfamily. They consist mainly of two large subfamilies: (i) conjugation systems that mediate interbacterial DNA transfer and (ii) effector translocators that deliver effector macromolecules into prokaryotic or eukaryotic cells. A few other T4SSs export DNA or proteins to the milieu, or import exogenous DNA. The T4SSs are defined by 6 or 12 conserved "core" subunits that respectively elaborate "minimized" systems in Gram-positive or -negative bacteria. However, many "expanded" T4SSs are built from "core" subunits plus numerous others that are system-specific, which presumptively broadens functional capabilities. Recently, there has been exciting progress in defining T4SS assembly pathways and architectures using a combination of fluorescence and cryoelectron microscopy. This review will highlight advances in our knowledge of structure-function relationships for model Gram-negative bacterial T4SSs, including "minimized" systems resembling the Agrobacterium tumefaciens VirB/VirD4 T4SS and "expanded" systems represented by the Helicobacter pylori Cag, Legionella pneumophila Dot/Icm, and F plasmid-encoded Tra T4SSs. Detailed studies of these model systems are generating new insights, some at atomic resolution, to long-standing questions concerning mechanisms of substrate recruitment, T4SS channel architecture, conjugative pilus assembly, and machine adaptations contributing to T4SS functional versatility.
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Affiliation(s)
- Tiago R D Costa
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, UK
| | - Laith Harb
- Department of Biochemistry and Biophysics and Center for Phage Technology, Texas A&M University, College Station, TX, USA
| | - Pratick Khara
- Department of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth, Houston, TX, USA
| | - Lanying Zeng
- Department of Biochemistry and Biophysics and Center for Phage Technology, Texas A&M University, College Station, TX, USA
| | - Bo Hu
- Department of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth, Houston, TX, USA
| | - Peter J Christie
- Department of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth, Houston, TX, USA
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17
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Varga MG, Wood CR, Butt J, Ryan ME, You WC, Pan K, Waterboer T, Epplein M, Shaffer CL. Immunostimulatory membrane proteins potentiate H. pylori-induced carcinogenesis by enabling CagA translocation. Gut Microbes 2021; 13:1-13. [PMID: 33382363 PMCID: PMC7781638 DOI: 10.1080/19490976.2020.1862613] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 11/04/2020] [Accepted: 11/26/2020] [Indexed: 02/07/2023] Open
Abstract
Infection with Helicobacter pylori is the single greatest risk factor for developing gastric adenocarcinoma. In prospective, population-based studies, seropositivity to the uncharacterized H. pylori proteins Hp0305 and Hp1564 was significantly associated with cancer risk in East Asia. However, the mechanism underlying this observation has not been elucidated. Here, we show that Hp0305 and Hp1564 act in concert with previously ascribed H. pylori virulence mechanisms to orchestrate cellular alterations that promote gastric carcinogenesis. In samples from 546 patients exhibiting premalignant gastric lesions, seropositivity to Hp0305 and Hp1564 was significantly associated with increased gastric atrophy across all stomach conditions. In vitro, depletion of Hp0305 and Hp1564 significantly reduced levels of gastric cell-associated bacteria and markedly impaired the ability of H. pylori to stimulate pro-inflammatory cytokine production. Remarkably, our studies revealed that Hp1564 is required for translocation of the oncoprotein CagA into gastric epithelial cells. Our data provide experimental insight into the molecular mechanisms governing novel H. pylori pathogenicity factors that are strongly associated with gastric disease and highlight the potential of Hp0305 and Hp1564 as robust molecular tools that can improve identification of individuals that are highly susceptible to gastric cancer. We demonstrate that Hp0305 and Hp1564 augment H. pylori-mediated inflammation and gastric cancer risk by promoting key bacteria-gastric cell interactions that facilitate delivery of oncogenic microbial cargo to target cells. Thus, therapeutically targeting microbial interactions driven by Hp0305/Hp1564 may enable focused H. pylori eradication strategies to prevent development of gastric malignancies in high-risk populations.
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Affiliation(s)
- Matthew G. Varga
- Department of Epidemiology, Lineberger Comprehensive Cancer Center and Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA
| | - Cecily R. Wood
- Department of Veterinary Science, University of Kentucky, Lexington, KY, USA
| | - Julia Butt
- Infections and Cancer Epidemiology, German Cancer Research Center, Heidelberg, Germany
| | - Mackenzie E. Ryan
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, KY, USA
| | - Wei-Cheng You
- Department of Cancer Epidemiology, Peking University Cancer Hospital and Institute, Beijing, China
| | - Kaifeng Pan
- Department of Cancer Epidemiology, Peking University Cancer Hospital and Institute, Beijing, China
| | - Tim Waterboer
- Infections and Cancer Epidemiology, German Cancer Research Center, Heidelberg, Germany
| | - Meira Epplein
- Department of Population Health Sciences and Duke Cancer Institute, Cancer Control and Population Sciences Program, Duke University, Durham, NC, USA
| | - Carrie L. Shaffer
- Department of Veterinary Science, University of Kentucky, Lexington, KY, USA
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, KY, USA
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY, USA
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18
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Temporal Control of the Helicobacter pylori Cag Type IV Secretion System in a Mongolian Gerbil Model of Gastric Carcinogenesis. mBio 2020; 11:mBio.01296-20. [PMID: 32605987 PMCID: PMC7327173 DOI: 10.1128/mbio.01296-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The Helicobacter pylori Cag type IV secretion system (T4SS) translocates the effector protein CagA and nonprotein bacterial constituents into host cells. In this study, we infected Mongolian gerbils with an H. pylori strain in which expression of the cagUT operon (required for Cag T4SS activity) is controlled by a TetR/tetO system. Transcript levels of cagU were significantly higher in gastric tissue from H. pylori-infected animals receiving doxycycline-containing chow (to derepress Cag T4SS activity) than in tissue from infected control animals receiving drug-free chow. At 3 months postinfection, infected animals receiving doxycycline had significantly increased gastric inflammation compared to infected control animals. Dysplasia (a premalignant histologic lesion) and/or invasive gastric adenocarcinoma were detected only in infected gerbils receiving doxycycline, not in infected control animals. We then conducted experiments in which Cag T4SS activity was derepressed during defined stages of infection. Continuous Cag T4SS activity throughout a 3-month time period resulted in higher rates of dysplasia and/or gastric cancer than observed when Cag T4SS activity was limited to early or late stages of infection. Cag T4SS activity for the initial 6 weeks of infection was sufficient for the development of gastric inflammation at the 3-month time point, with gastric cancer detected in a small proportion of animals. These experimental results, together with previous studies of cag mutant strains, provide strong evidence that Cag T4SS activity contributes to gastric carcinogenesis and help to define the stages of H. pylori infection during which Cag T4SS activity causes gastric alterations relevant for cancer pathogenesis.IMPORTANCE The "hit-and-run model" of carcinogenesis proposes that an infectious agent triggers carcinogenesis during initial stages of infection and that the ongoing presence of the infectious agent is not required for development of cancer. H. pylori infection and actions of CagA (an effector protein designated a bacterial oncoprotein, secreted by the Cag T4SS) are proposed to constitute a paradigm for hit-and-run carcinogenesis. In this study, we report the development of methods for controlling H. pylori Cag T4SS activity in vivo and demonstrate that Cag T4SS activity contributes to gastric carcinogenesis. We also show that Cag T4SS activity during an early stage of infection is sufficient to initiate a cascade of cellular alterations leading to gastric inflammation and gastric cancer at later time points.
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19
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Identification of Pathogenicity Island Genes Associated with Loss of Type IV Secretion Function during Murine Infection with Helicobacter pylori. Infect Immun 2020; 88:IAI.00801-19. [PMID: 32205402 DOI: 10.1128/iai.00801-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 03/16/2020] [Indexed: 01/18/2023] Open
Abstract
Chronic Helicobacter pylori colonization in animal models often leads to downregulation of the type IV secretion system (T4SS), typically by recombination in cagY, which is an essential T4SS gene. However, 17 other cag pathogenicity island (cagPAI) genes, as well as some non-cagPAI genes, are also essential for T4SS function. To get a more complete picture of how H. pylori regulates the T4SS during animal colonization, we examined cagY in 534 mouse-passaged isolates that lost T4SS function, defined as a normalized interleukin-8 (IL-8) value of <0.3 relative to the input H. pylori strain PMSS1. In order to analyze the genetic changes in the strains with unchanged cagY, we sequenced the entire pathogenicity island of 60 such isolates using single-molecule, real-time (SMRT) sequencing technology (PacBio, Menlo Park, CA), and we compared the results to the PMSS1 wild type (WT). Of the 534 strains, 271 (51%) showed evidence of recombination in cagY, but we also found indels or nonsynonymous changes in 13 other essential cagPAI genes implicated in H. pylori T4SS function, most commonly cag5, cag10, and cagA While cagY recombination is the most common mechanism by which H. pylori downregulates T4SS function during murine infection, loss of function is also associated with changes in other essential cagPAI genes.
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20
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McClain MS, Voss BJ, Cover TL. Lipoprotein Processing and Sorting in Helicobacter pylori. mBio 2020; 11:e00911-20. [PMID: 32430470 PMCID: PMC7240156 DOI: 10.1128/mbio.00911-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 04/20/2020] [Indexed: 12/14/2022] Open
Abstract
Our current understanding of lipoprotein synthesis and localization in Gram-negative bacteria is based primarily on studies of Escherichia coli Newly synthesized E. coli prolipoproteins undergo posttranslational modifications catalyzed by three essential enzymes (Lgt, LspA, and Lnt). The mature lipoproteins are then sorted to the inner or outer membrane via the Lol system (LolABCDE). Recent studies suggested that this paradigm may not be universally applicable among different classes of proteobacteria. In this study, we conducted a systematic analysis of lipoprotein processing and sorting in Helicobacter pylori, a member of the Epsilonproteobacteria that colonizes the human stomach. We show that H. pylorilgt, lspA, and lnt homologs can complement conditionally lethal E. coli mutant strains in which expression of these genes is conditionally regulated. Mutagenesis studies and analyses of conditionally lethal H. pylori mutant strains indicate that lgt and lspA are essential for H. pylori growth but lnt is dispensable. H. pylorilolA and the single lolC (or lolE) homolog are also essential genes. We then explored the role of lipoproteins in H. pylori Cag type IV secretion system (Cag T4SS) activity. Comparative analysis of the putative VirB7 homolog CagT in wild-type and lnt mutant H. pylori strains indicates that CagT undergoes amino-terminal modifications consistent with lipidation, and we show that CagT lipidation is essential for CagT stability and Cag T4SS function. This work demonstrates that lipoprotein synthesis and localization in H. pylori diverge from the canonical pathways and that lipidation of a T4SS component is necessary for H. pylori Cag T4SS activity.IMPORTANCE Bacterial lipoproteins have diverse roles in multiple aspects of bacterial physiology, antimicrobial resistance, and pathogenesis. Dedicated pathways direct the posttranslational lipidation and localization of lipoproteins, but there is considerable variation in these pathways among the proteobacteria. In this study, we characterized the proteins responsible for lipoprotein synthesis and localization in Helicobacter pylori, a member of the Epsilonproteobacteria that contributes to stomach cancer pathogenesis. We also provide evidence suggesting that lipidation of CagT, a component of the H. pylori Cag T4SS, is required for delivery of the H. pylori CagA oncoprotein into human gastric cells. Overall, these results constitute the first systematic analysis of H. pylori lipoprotein production and localization pathways and reveal how these processes in H. pylori differ from corresponding pathways in model proteobacteria.
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Affiliation(s)
- Mark S McClain
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Bradley J Voss
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Timothy L Cover
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, USA
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21
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The Helicobacter pylori Cag Type IV Secretion System. Trends Microbiol 2020; 28:682-695. [PMID: 32451226 DOI: 10.1016/j.tim.2020.02.004] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 01/30/2020] [Accepted: 02/25/2020] [Indexed: 12/24/2022]
Abstract
Colonization of the human stomach with Helicobacter pylori strains containing the cag pathogenicity island is a risk factor for development of gastric cancer. The cag pathogenicity island contains genes encoding a secreted effector protein (CagA) and components of a type IV secretion system (Cag T4SS). The molecular architecture of the H. pylori Cag T4SS is substantially more complex than that of prototype T4SSs in other bacterial species. In this review, we discuss recent discoveries pertaining to the structure and function of the Cag T4SS and its role in gastric cancer pathogenesis.
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22
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Bacterial Energetic Requirements for Helicobacter pylori Cag Type IV Secretion System-Dependent Alterations in Gastric Epithelial Cells. Infect Immun 2020; 88:IAI.00790-19. [PMID: 31712269 DOI: 10.1128/iai.00790-19] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Accepted: 11/06/2019] [Indexed: 02/08/2023] Open
Abstract
Helicobacter pylori colonizes the stomach in about half of the world's population. H. pylori strains containing the cag pathogenicity island (cag PAI) are associated with a higher risk of gastric adenocarcinoma or peptic ulcer disease than cag PAI-negative strains. The cag PAI encodes a type IV secretion system (T4SS) that mediates delivery of the CagA effector protein as well as nonprotein bacterial constituents into gastric epithelial cells. H. pylori-induced nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation and interleukin-8 (IL-8) secretion are attributed to T4SS-dependent delivery of lipopolysaccharide metabolites and peptidoglycan into host cells, and Toll-like receptor 9 (TLR9) activation is attributed to delivery of bacterial DNA. In this study, we analyzed the bacterial energetic requirements associated with these cellular alterations. Mutant strains lacking Cagα, Cagβ, or CagE (putative ATPases corresponding to VirB11, VirD4, and VirB4 in prototypical T4SSs) were capable of T4SS core complex assembly but defective in CagA translocation into host cells. Thus, the three Cag ATPases are not functionally redundant. Cagα and CagE were required for H. pylori-induced NF-κB activation, IL-8 secretion, and TLR9 activation, but Cagβ was dispensable for these responses. We identified putative ATP-binding motifs (Walker-A and Walker-B) in each of the ATPases and generated mutant strains in which these motifs were altered. Each of the Walker box mutant strains exhibited properties identical to those of the corresponding deletion mutant strains. These data suggest that Cag T4SS-dependent delivery of nonprotein bacterial constituents into host cells occurs through mechanisms different from those used for recruitment and delivery of CagA into host cells.
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Hanafiah A, Lopes BS. Genetic diversity and virulence characteristics of Helicobacter pylori isolates in different human ethnic groups. INFECTION GENETICS AND EVOLUTION 2019; 78:104135. [PMID: 31837482 DOI: 10.1016/j.meegid.2019.104135] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 12/03/2019] [Accepted: 12/06/2019] [Indexed: 02/07/2023]
Abstract
Helicobacter pylori is the most predominant bacterium in almost 50% of the world's population and colonization causes a persistent inflammatory response leading to chronic gastritis. It shows high genetic diversity and individuals generally harbour a distinct bacterial population. With the advancement of whole-genome sequencing technology, new H. pylori subpopulations have been identified that show admixture between various H. pylori strains. Genotypic variation of H. pylori may be related to the presence of virulence factors among strains and is associated with different outcomes of infection in different individuals. This review summarizes the genetic diversity in H. pylori strain populations and its virulence characteristics responsible for variable outcomes in different ethnic groups.
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Affiliation(s)
- Alfizah Hanafiah
- Department of Medical Microbiology & Immunology, Faculty of Medicine, Universiti Kebangsaan Malaysia, 56000 Cheras, Kuala Lumpur, Malaysia.
| | - Bruno S Lopes
- Department of Medical Microbiology, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, 0:025 Polwarth Building, Aberdeen AB25 2ZD, United Kingdom.
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Ansari S, Yamaoka Y. Helicobacter pylori Virulence Factors Exploiting Gastric Colonization and its Pathogenicity. Toxins (Basel) 2019; 11:E677. [PMID: 31752394 PMCID: PMC6891454 DOI: 10.3390/toxins11110677] [Citation(s) in RCA: 118] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 11/15/2019] [Accepted: 11/16/2019] [Indexed: 02/07/2023] Open
Abstract
Helicobacter pylori colonizes the gastric epithelial cells of at least half of the world's population, and it is the strongest risk factor for developing gastric complications like chronic gastritis, ulcer diseases, and gastric cancer. To successfully colonize and establish a persistent infection, the bacteria must overcome harsh gastric conditions. H. pylori has a well-developed mechanism by which it can survive in a very acidic niche. Despite bacterial factors, gastric environmental factors and host genetic constituents together play a co-operative role for gastric pathogenicity. The virulence factors include bacterial colonization factors BabA, SabA, OipA, and HopQ, and the virulence factors necessary for gastric pathogenicity include the effector proteins like CagA, VacA, HtrA, and the outer membrane vesicles. Bacterial factors are considered more important. Here, we summarize the recent information to better understand several bacterial virulence factors and their role in the pathogenic mechanism.
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Affiliation(s)
- Shamshul Ansari
- Department of Microbiology, Chitwan Medical College and Teaching Hospital, Bharatpur 44200, Chitwan, Nepal;
| | - Yoshio Yamaoka
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Idaigaoka, Hasama-machi, Yufu, Oita 879-5593, Japan
- Global Oita Medical Advanced Research Center for Health, Idaigaoka, Hasama-machi, Yufu, Oita 879-5593, Japan
- Department of Medicine, Gastroenterology and Hepatology Section, Baylor College of Medicine, 2002 Holcombe Blvd., Houston, TX 77030, USA
- Borneo Medical and Health Research Centre, Universiti Malaysia Sabah, Kota Kinabaru, Sabah 88400, Malaysia
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Activity and Functional Importance of Helicobacter pylori Virulence Factors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1149:35-56. [PMID: 31016624 DOI: 10.1007/5584_2019_358] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Helicobacter pylori is a very successful Gram-negative pathogen colonizing the stomach of humans worldwide. Infections with this bacterium can generate pathologies ranging from chronic gastritis and peptic ulceration to gastric cancer. The best characterized H. pylori virulence factors that cause direct cell damage include an effector protein encoded by the cytotoxin-associated gene A (CagA), a type IV secretion system (T4SS) encoded in the cag-pathogenicity island (cag PAI), vacuolating cytotoxin A (VacA), γ-glutamyl transpeptidase (GGT), high temperature requirement A (HtrA, a serine protease) and cholesterol glycosyl-transferase (CGT). Since these H. pylori factors are either surface-exposed, secreted or translocated, they can directly interact with host cell molecules and are able to hijack cellular functions. Studies on these bacterial factors have progressed substantially in recent years. Here, we review the current status in the characterization of signaling cascades by these factors in vivo and in vitro, which comprise the disruption of cell-to-cell junctions, induction of membrane rearrangements, cytoskeletal dynamics, proliferative, pro-inflammatory, as well as, pro-apoptotic and anti-apoptotic responses or immune evasion. The impact of these signal transduction modules in the pathogenesis of H. pylori infections is discussed.
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Wroblewski LE, Choi E, Petersen C, Delgado AG, Piazuelo MB, Romero-Gallo J, Lantz TL, Zavros Y, Coffey RJ, Goldenring JR, Zemper AE, Peek RM. Targeted mobilization of Lrig1 + gastric epithelial stem cell populations by a carcinogenic Helicobacter pylori type IV secretion system. Proc Natl Acad Sci U S A 2019; 116:19652-19658. [PMID: 31488717 PMCID: PMC6765285 DOI: 10.1073/pnas.1903798116] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Helicobacter pylori-induced gastritis is the strongest risk factor for gastric adenocarcinoma, a malignancy preceded by a series of well-defined histological stages, including metaplasia. One microbial constituent that augments cancer risk is the cag type 4 secretion system (T4SS), which translocates the oncoprotein CagA into host cells. Aberrant stem cell activation is linked to carcinogenesis, and Lrig1 (leucine-rich repeats and Ig-like domains 1) marks a distinct population of progenitor cells. We investigated whether microbial effectors with carcinogenic potential influence Lrig1 progenitor cells ex vivo and via lineage expansion within H. pylori-infected gastric mucosa. Lineage tracing was induced in Lrig1-CreERT2/+;R26R-YFP/+ (Lrig1/YFP) mice that were uninfected or subsequently infected with cag+H. pylori or an isogenic cagE- mutant (nonfunctional T4SS). In contrast to infection with wild-type (WT) H. pylori for 2 wk, infection for 8 wk resulted in significantly increased inflammation and proliferation in the corpus and antrum compared with uninfected or mice infected with the cagE- mutant. WT H. pylori-infected mice harbored significantly higher numbers of Lrig1/YFP epithelial cells that coexpressed UEA1 (surface cell marker). The number of cells coexpressing intrinsic factor (chief cell marker), YFP (lineage marker), and GSII lectin (spasmolytic polypeptide-expressing metaplasia marker) were increased only by WT H. pylori In human samples, Lrig1 expression was significantly increased in lesions with premalignant potential compared with normal mucosa or nonatrophic gastritis. In conclusion, chronic H. pylori infection stimulates Lrig1-expressing progenitor cells in a cag-dependent manner, and these reprogrammed cells give rise to a full spectrum of differentiated cells.
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Affiliation(s)
- Lydia E Wroblewski
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232;
| | - Eunyoung Choi
- Nashville VA Medical Center, US Department of Veterans Affairs, Nashville, TN 37212
- Section of Surgical Sciences, Vanderbilt University Medical Center, Nashville, TN 37232
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Christine Petersen
- Section of Surgical Sciences, Vanderbilt University Medical Center, Nashville, TN 37232
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Alberto G Delgado
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232
| | - M Blanca Piazuelo
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Judith Romero-Gallo
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Tyler L Lantz
- Department of Biology, University of Oregon, Eugene, OR 97403
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
| | - Yana Zavros
- Department of Pharmacology and System Physiology, University of Cincinnati, Cincinnati, OH 45221
| | - Robert J Coffey
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232
- Nashville VA Medical Center, US Department of Veterans Affairs, Nashville, TN 37212
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232
- Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN 37232
| | - James R Goldenring
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232
- Nashville VA Medical Center, US Department of Veterans Affairs, Nashville, TN 37212
- Section of Surgical Sciences, Vanderbilt University Medical Center, Nashville, TN 37232
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Anne E Zemper
- Department of Biology, University of Oregon, Eugene, OR 97403
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
| | - Richard M Peek
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232;
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232
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Chang YW, Shaffer CL, Rettberg LA, Ghosal D, Jensen GJ. In Vivo Structures of the Helicobacter pylori cag Type IV Secretion System. Cell Rep 2019; 23:673-681. [PMID: 29669273 PMCID: PMC5931392 DOI: 10.1016/j.celrep.2018.03.085] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 01/16/2018] [Accepted: 03/19/2018] [Indexed: 02/06/2023] Open
Abstract
The type IV secretion system (T4SS) is a versatile nanomachine that translocates diverse effector molecules between microbes and into eukaryotic cells. Here, using electron cryotomography, we reveal the molecular architecture of the Helicobacter pylori cag T4SS. Although most components are unique to H. pylori, the cag T4SS exhibits remarkable architectural similarity to other T4SSs. Our images revealed that, when H. pylori encounters host cells, the bacterium elaborates membranous tubes perforated by lateral ports. Sub-tomogram averaging of the cag T4SS machinery revealed periplasmic densities associated with the outer membrane, a central stalk, and peripheral wing-like densities. Additionally, we resolved pilus-like rod structures extending from the cag T4SS into the inner membrane, as well as densities within the cytoplasmic apparatus corresponding to a short central barrel surrounded by four longer barrels. Collectively, these studies reveal the structure of a dynamic molecular machine that evolved to function in the human gastric niche.
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Affiliation(s)
- Yi-Wei Chang
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Carrie L Shaffer
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Lee A Rettberg
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Howard Hughes Medical Institute, Pasadena, CA 91125, USA
| | - Debnath Ghosal
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Grant J Jensen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Howard Hughes Medical Institute, Pasadena, CA 91125, USA.
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28
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Buß M, Tegtmeyer N, Schnieder J, Dong X, Li J, Springer TA, Backert S, Niemann HH. Specific high affinity interaction of Helicobacter pylori CagL with integrin α V β 6 promotes type IV secretion of CagA into human cells. FEBS J 2019; 286:3980-3997. [PMID: 31197920 DOI: 10.1111/febs.14962] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 04/12/2019] [Accepted: 06/10/2019] [Indexed: 12/21/2022]
Abstract
CagL is an essential pilus surface component of the virulence-associated type IV secretion system (T4SS) employed by Helicobacter pylori to translocate the oncogenic effector protein CagA into human gastric epithelial cells. CagL contains an RGD motif and integrin α5 β1 is widely accepted as its host cell receptor. Here, we show that CagL binds integrin αV β6 with substantially higher affinity and that this interaction is functionally important. Cell surface expression of αV β6 on various cell lines correlated perfectly with cell adhesion to immobilized CagL and with binding of soluble CagL to cells. We found no such correlation for α5 β1 . The purified αV β6 ectodomain bound CagL with high affinity. This interaction was highly specific, as the affinity of CagL for other RGD-binding integrins was two to three orders of magnitude weaker. Mutation of either conserved leucine in the CagL RGDLXXL motif, a motif that generally confers specificity for integrin αV β6 and αV β8 , lowered the affinity of CagL for αV β6 . Stable expression of αV β6 in αV β6 -negative but α5 β1 -expressing human cells promoted two hallmarks of the functional H. pylori T4SS, namely translocation of CagA into host cells and induction of interleukin-8 secretion by host cells. These findings suggest that integrin αV β6 , although not essential for T4SS function, represents an important host cell receptor for CagL.
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Affiliation(s)
- Maren Buß
- Structural Biochemistry, Department of Chemistry, Bielefeld University, Germany
| | - Nicole Tegtmeyer
- Division of Microbiology, Department of Biology, Friedrich-Alexander-University, Erlangen-Nuremberg, Germany
| | - Jennifer Schnieder
- Structural Biochemistry, Department of Chemistry, Bielefeld University, Germany
| | - Xianchi Dong
- Children's Hospital Boston, MA, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Jing Li
- Children's Hospital Boston, MA, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Timothy A Springer
- Children's Hospital Boston, MA, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Steffen Backert
- Division of Microbiology, Department of Biology, Friedrich-Alexander-University, Erlangen-Nuremberg, Germany
| | - Hartmut H Niemann
- Structural Biochemistry, Department of Chemistry, Bielefeld University, Germany
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29
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Abstract
Helicobacter pylori colonizes about half of humans worldwide, and its presence in the gastric mucosa is associated with an increased risk of gastric adenocarcinoma, gastric lymphoma, and peptic ulcer disease. H. pylori strains carrying the cag pathogenicity island (cagPAI) are associated with increased risk of disease progression. The cagPAI encodes the Cag type IV secretion system (CagT4SS), which delivers the CagA oncoprotein and other effector molecules into human gastric epithelial cells. We visualized structures of native and mutant CagT4SS machines on the H. pylori cell envelope by cryoelectron tomography. Individual H. pylori cells contain multiple CagT4SS nanomachines, each composed of a wheel-shaped outer membrane complex (OMC) with 14-fold symmetry and an inner membrane complex (IMC) with 6-fold symmetry. CagX, CagY, and CagM are required for assembly of the OMC, whereas strains lacking Cag3 and CagT produce outer membrane complexes lacking peripheral components. The IMC, which has never been visualized in detail, is configured as six tiers in cross-section view and three concentric rings surrounding a central channel in end-on view. The IMC contains three T4SS ATPases: (i) VirB4-like CagE, arranged as a hexamer of dimers at the channel entrance; (ii) a hexamer of VirB11-like Cagα, docked at the base of the CagE hexamer; and (iii) VirD4-like Cagβ and other unspecified Cag subunits, associated with the stacked CagE/Cagα complex and forming the outermost rings. The CagT4SS and recently solved Legionella pneumophila Dot/Icm system comprise new structural prototypes for the T4SS superfamily.IMPORTANCE Bacterial type IV secretion systems (T4SSs) have been phylogenetically grouped into two subfamilies. The T4ASSs, represented by the Agrobacterium tumefaciens VirB/VirD4T4SS, include "minimized" machines assembled from 12 VirB- and VirD4-like subunits and compositionally larger systems such as the Helicobacter pylori CagT4SS T4BSSs encompass systems closely related in subunit composition to the Legionella pneumophila Dot/IcmT4SS Here, we present structures of native and mutant H. pylori Cag machines determined by in situ cryoelectron tomography. We identify distinct outer and inner membrane complexes and, for the first time, visualize structural contributions of all three "signature" ATPases of T4SSs at the cytoplasmic entrance of the translocation channel. Despite their evolutionary divergence, the CagT4SS aligns structurally much more closely to the Dot/IcmT4SS than an available VirB/VirD4 subcomplex. Our findings highlight the diversity of T4SSs and suggest a structural classification scheme in which T4SSs are grouped as minimized VirB/VirD4-like or larger Cag-like and Dot/Icm-like systems.
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30
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Boudaher E, Shaffer CL. Inhibiting bacterial secretion systems in the fight against antibiotic resistance. MEDCHEMCOMM 2019; 10:682-692. [PMID: 31741728 DOI: 10.1039/c9md00076c] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 04/22/2019] [Indexed: 12/11/2022]
Abstract
Antimicrobial resistance is a mounting global health crisis that threatens a resurgence of life-threatening bacterial infections. Despite intensive drug discovery efforts, the rate of antimicrobial resistance outpaces the discovery of new antibiotic agents. One of the major mechanisms driving the rapid propagation of antibiotic resistance is bacterial conjugation mediated by the versatile type IV secretion system (T4SS). The search for therapeutic compounds that prevent the spread of antibiotic resistance via T4SS-dependent mechanisms has identified several promising molecular scaffolds that disrupt resistance determinant dissemination. In this brief review, we highlight the progress and potential of conjugation inhibitors and anti-virulence compounds that target diverse T4SS machineries. These studies provide a solid foundation for the future development of potent, dual-purpose molecular scaffolds that can be used as biochemical tools to probe type IV secretion mechanisms and target bacterial conjugation in clinical settings to prevent the dissemination of antibiotic resistance throughout microbial populations.
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Affiliation(s)
- Elizabeth Boudaher
- University of Kentucky , Department of Veterinary Science , Gluck Equine Research Center , 1400 Nicholasville Road , Lexington , KY , USA . ; Tel: +1 (859) 218 1168
| | - Carrie L Shaffer
- University of Kentucky , Department of Veterinary Science , Gluck Equine Research Center , 1400 Nicholasville Road , Lexington , KY , USA . ; Tel: +1 (859) 218 1168.,University of Kentucky , Department of Microbiology, Immunology, and Molecular Genetics , 800 Rose Street , Lexington , KY , USA.,University of Kentucky , Department of Pharmaceutical Sciences , 789 South Limestone Street , Lexington , KY , USA
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31
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Abstract
The bacterial type IV secretion systems (T4SSs) are a functionally diverse superfamily of secretion systems found in many species of bacteria. Collectively, the T4SSs translocate DNA and monomeric and multimeric protein substrates to bacterial and eukaryotic cell types. T4SSs are composed of two large subfamilies, the conjugation machines and the effector translocators that transmit their cargoes through establishment of direct donor-target cell contacts, and a third small subfamily capable of importing or exporting substrates from or to the milieu. This review summarizes recent mechanistic and structural findings that are shedding new light on how T4SSs have evolved such functional diversity. Translocation signals are now known to be located C terminally or embedded internally in structural folds; these signals in combination with substrate-associated adaptor proteins mediate the docking of specific substrate repertoires to cognate VirD4-like receptors. For the Legionella pneumophila Dot/Icm system, recent work has elucidated the structural basis for adaptor-dependent substrate loading onto the VirD4-like DotL receptor. Advances in definition of T4SS machine structures now allow for detailed comparisons of nanomachines closely related to the Agrobacterium tumefaciens VirB/VirD4 T4SS with those more distantly related, e.g., the Dot/Icm and Helicobacter pylori Cag T4SSs. Finally, it is increasingly evident that T4SSs have evolved a variety of mechanisms dependent on elaboration of conjugative pili, membrane tubes, or surface adhesins to establish productive contacts with target cells. T4SSs thus have evolved extreme functional diversity through a plethora of adaptations impacting substrate selection, machine architecture, and target cell binding.
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32
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Abstract
Type IV secretion systems (T4SSs) are nanomachines that Gram-negative, Gram-positive bacteria, and some archaea use to transport macromolecules across their membranes into bacterial or eukaryotic host targets or into the extracellular milieu. They are the most versatile secretion systems, being able to deliver both proteins and nucleoprotein complexes into targeted cells. By mediating conjugation and/or competence, T4SSs play important roles in determining bacterial genome plasticity and diversity; they also play a pivotal role in the spread of antibiotic resistance within bacterial populations. T4SSs are also used by human pathogens such as Legionella pneumophila, Bordetella pertussis, Brucella sp., or Helicobacter pylori to sustain infection. Since they are essential virulence factors for these important pathogens, T4SSs might represent attractive targets for vaccines and therapeutics. The best-characterized conjugative T4SSs of Gram-negative bacteria are composed of twelve components that are conserved across many T4SSs. In this chapter, we will review our current structural knowledge on the T4SSs by describing the structures of the individual components and how they assemble into large macromolecular assemblies. With the combined efforts of X-ray crystallography, nuclear magnetic resonance (NMR), and more recently electron microscopy, structural biology of the T4SS has made spectacular progress during the past fifteen years and has unraveled the properties of unique proteins and complexes that assemble dynamically in a highly sophisticated manner.
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33
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Yadegar A, Mohabati Mobarez A, Zali MR. Genetic diversity and amino acid sequence polymorphism in Helicobacter pylori CagL hypervariable motif and its association with virulence markers and gastroduodenal diseases. Cancer Med 2019; 8:1619-1632. [PMID: 30873747 PMCID: PMC6488209 DOI: 10.1002/cam4.1941] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 11/22/2018] [Accepted: 12/03/2018] [Indexed: 12/19/2022] Open
Abstract
Genetic variability in cagL gene especially within the Helicobacter pylori CagL hypervariable motif (CagLHM) may affect the development of gastric cancer. Therefore, this study was conducted to investigate the association of CagL diversity with clinical outcomes and with H pylori virulence markers. A total of 126 patients with different gastric diseases including non-ulcer dyspepsia (NUD), peptic ulcer disease (PUD), gastric erosion (GE), and gastric cancer (GC) were enrolled. H pylori was cultured from gastric biopsies, and the isolates were screened for the presence of cagL, cagA, vacA, babA2, sabA, and cagPAI integrity by PCR. The amino acid polymorphisms of cagL were analyzed using DNA sequencing. We isolated 61 (48.4%) H pylori strains from 36 NUD, eight PUD, 12 GE, and five GC patients. Almost all isolates were cagL positive (97%), and their RGD, RHS, and SKIIVK motifs were highly conserved. Among 10 CagLHM variants identified, NEIGQ and NKIGQ were detected as the most prevalent sequences. Interestingly, a significant association was found between the presence of NKMGK and PUD (P = 0.002). Notably, the NEIGQ isolates with multiple C-type EPIYA repeat that carried intact cagPAI correlated with disease risk for PUD, GE, and GC (P = 0.021). In conclusion, we identified novel variants of H pylori CagLHM sequences in Iranian population such as NKMGK, which was associated with disease risk for PUD. Further studies using a large number of strains are required to better clarify the function of certain CagLHM motifs in gastric carcinogenesis and disease outcome.
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Affiliation(s)
- Abbas Yadegar
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ashraf Mohabati Mobarez
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Mohammad Reza Zali
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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34
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Javed S, Skoog EC, Solnick JV. Impact of Helicobacter pylori Virulence Factors on the Host Immune Response and Gastric Pathology. Curr Top Microbiol Immunol 2019; 421:21-52. [PMID: 31123884 DOI: 10.1007/978-3-030-15138-6_2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Helicobacter pylori chronically infects nearly half the world's population, yet most of those infected remain asymptomatic throughout their lifetime. The outcome of infection-peptic ulcer disease or gastric cancer versus asymptomatic colonization-is a product of host genetics, environmental influences, and differences in bacterial virulence factors. Here, we review the current understanding of the cag pathogenicity island (cagPAI), the vacuolating cytotoxin (VacA), and a large family of outer membrane proteins (OMPs), which are among the best understood H. pylori virulence determinants that contribute to disease. Each of these virulence factors is characterized by allelic and phenotypic diversity that is apparent within and across individuals, as well as over time, and modulates inflammation. From the bacterial perspective, inflammation is probably a necessary evil because it promotes nutrient acquisition, but at the cost of reduction in bacterial load and therefore decreases the chance of transmission to a new host. The general picture that emerges is one of a chronic bacterial infection that is dependent on both inducing and carefully regulating the host inflammatory response. A better understanding of these regulatory mechanisms may have implications for the control of chronic inflammatory diseases that are increasingly common causes of human morbidity and mortality.
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Affiliation(s)
- Sundus Javed
- Department of Medicine, Department of Microbiology & Immunology, Center for Comparative Medicine, University of California, Davis School of Medicine, Davis, CA, 95616, USA.,Department of Biosciences, COMSATS Institute of Information Technology, Islamabad, Pakistan
| | - Emma C Skoog
- Department of Medicine, Department of Microbiology & Immunology, Center for Comparative Medicine, University of California, Davis School of Medicine, Davis, CA, 95616, USA
| | - Jay V Solnick
- Department of Medicine, Department of Microbiology & Immunology, Center for Comparative Medicine, University of California, Davis School of Medicine, Davis, CA, 95616, USA. .,Center for Comparative Medicine, University of California, Davis, Davis, CA, 95616, USA.
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35
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Bonsor DA, Sundberg EJ. Roles of Adhesion to Epithelial Cells in Gastric Colonization by Helicobacter pylori. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1149:57-75. [PMID: 31016628 DOI: 10.1007/5584_2019_359] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Helicobacter pylori adherence to host epithelial cells is essential for its survival against the harsh conditions of the stomach and for successful colonization. Adherence of H. pylori is achieved through several related families of outer membrane proteins and proteins of a type IV secretion system (T4SS), which bridge H. pylori to host cells through protein-protein and other protein-ligand interactions. Local environmental conditions such as cell type, available host cell surface proteins and/or ligands, as well as responses by the host immune system force H. pylori to alter expression of these proteins to adapt quickly to the local environment in order to colonize and survive. Some of these host-pathogen interactions appear to function in a "catch-and-release" manner, regulated by reversible binding at varying pH and allowing H. pylori to detach itself from cells or debris sloughed off the gastric epithelial lining in order to return for subsequent productive interactions. Other interactions between bacterial adhesin proteins and host adhesion molecules, however, appear to function as a committed step in certain pathogenic processes, such as translocation of the CagA oncoprotein through the H. pylori T4SS and into host gastric epithelial cells. Understanding these adhesion interactions is critical for devising new therapeutic strategies, as they are responsible for the earliest stage of infection and its maintenance. This review will discuss the expression and regulation of several outer membrane proteins and CagL, how they engage their known host cell protein/ligand targets, and their effects on clinical outcome.
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Affiliation(s)
- Daniel A Bonsor
- Institute of Human Virology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Eric J Sundberg
- Institute of Human Virology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD, USA. .,Department of Medicine, University of Maryland School of Medicine, University of Maryland, Baltimore, MD, USA. .,Department of Microbiology and Immunology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD, USA.
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Ogunyemi SO, Fang Y, Qiu W, Li B, Chen J, Yang M, Hong X, Luo J, Wang Y, Sun G. Role of type IV secretion system genes in virulence of rice bacterial brown stripe pathogen Acidovorax oryzae strain RS-2. Microb Pathog 2018; 126:343-350. [PMID: 30468852 DOI: 10.1016/j.micpath.2018.11.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 11/12/2018] [Accepted: 11/12/2018] [Indexed: 10/27/2022]
Abstract
Type IV secretion system (T4SS) is a specialized nanomachine that is utilized for the pathogenicity of gram-negative bacteria. However, the role of T4SS genes in virulence of rice bacterial brown stripe pathogen Acidovorax oryzae (Ao) strain RS-2 is not clear, which contains T4SS gene cluster based on genome-wide analysis. Here we compared the virulence-related phenotypes between the wild-type strain RS-2 and nine T4SS mutants, which were constructed in this study. Results indicated that mutation of pilT, pilM, pilQ, or pilZ3 genes not only significantly reduced bacterial virulence, but also caused a reduction of 20.4-62.0% in biofilm formation and 37.7-47.7% reduction in motility, but had no effect on exopolysaccharide (EPS) production or extracellular enzymatic activities when compared to the wild type. The four T4SS genes had a differential effect on bacterial growth after 24 h post-incubation. The complemented strains of the four T4SS mutants restored similar virulence symptom as the wild type. In addition, no change was observed in bacterial virulence by mutation of the other five T4SS genes. Totally, these results demonstrated that T4SS played vital roles in bacterial virulence, motility and biofilm formation in plant pathogen Ao strain RS-2.
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Affiliation(s)
- Solabomi Olaitan Ogunyemi
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 310058, Hangzhou, China; Department of Crop Protection, Federal University of Agriculture Abeokuta, Abeokuta, Nigeria
| | - Yushi Fang
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 310058, Hangzhou, China
| | - Wen Qiu
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 310058, Hangzhou, China.
| | - Bin Li
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 310058, Hangzhou, China
| | - Jie Chen
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 310058, Hangzhou, China
| | - Min Yang
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 310058, Hangzhou, China
| | - Xianxian Hong
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 310058, Hangzhou, China
| | - Jinyan Luo
- Department of Plant Quarantine, Shanghai Extension and Service Center of Agriculture Technology, Shanghai 201103, China
| | - Yangli Wang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, 310021, Hangzhou, China.
| | - Guochang Sun
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, 310021, Hangzhou, China
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Integrin but not CEACAM receptors are dispensable for Helicobacter pylori CagA translocation. PLoS Pathog 2018; 14:e1007359. [PMID: 30365569 PMCID: PMC6231679 DOI: 10.1371/journal.ppat.1007359] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 11/12/2018] [Accepted: 09/26/2018] [Indexed: 02/08/2023] Open
Abstract
Translocation of the Helicobacter pylori (Hp) cytotoxin-associated gene A (CagA) effector protein via the cag-Type IV Secretion System (cag-T4SS) into host cells is a hallmark of infection with Hp and a major risk factor for severe gastric diseases, including gastric cancer. To mediate the injection of CagA, Hp uses a membrane-embedded syringe-like molecular apparatus extended by an external pilus-like rod structure that binds host cell surface integrin heterodimers. It is still largely unclear how the interaction of the cag-T4SS finally mediates translocation of the CagA protein into the cell cytoplasm. Recently certain carcinoembryonic antigen-related cell adhesion molecules (CEACAMs), acting as receptor for the Hp outer membrane adhesin HopQ, have been identified to be involved in the process of CagA host cell injection. Here, we applied the CRISPR/Cas9-knockout technology to generate defined human gastric AGS and KatoIII integrin knockout cell lines. Although confocal laser scanning microscopy revealed a co-localization of Hp and β1 integrin heterodimers on gastric epithelial cells, Hp infection studies using the quantitative and highly sensitive Hp β-lactamase reporter system clearly show that neither β1 integrin heterodimers (α1β1, α2β1 or α5β1), nor any other αβ integrin heterodimers on the cell surface are essential for CagA translocation. In contrast, deletion of the HopQ adhesin in Hp, or the simultaneous knockout of the receptors CEACAM1, CEACAM5 and CEACAM6 in KatoIII cells abolished CagA injection nearly completely, although bacterial binding was only reduced to 50%. These data provide genetic evidence that the cag-T4SS-mediated interaction of Hp with cell surface integrins on human gastric epithelial cells is not essential for CagA translocation, but interaction of Hp with CEACAM receptors is facilitating CagA translocation by the cag-T4SS of this important microbe. The Cag Type IV secretion system of Helicobacter pylori (Hp) interacts with host cell integrins and injects the bacterial oncoprotein CagA into host cells thereby contributing to inflammation and carcinogenesis during chronic infection. Binding of β1 integrin receptors by the CagA protein and the type IV secretion system is well described by many research groups, but its function for CagA translocation is not well understood. We report here that this interaction is not essential for the function of the secretion system and for CagA injection into the gastric epithelial cells lines AGS and KatoIII. However, the bacterial binding to a set of specific receptors called carcinoembryonic antigen-related cell adhesion molecules (CEACAMs) by the Hp outer membrane protein HopQ is a prerequisite for CagA translocation. Interestingly, other bacterial adhesins and the mediated binding events do not have a similar effect on CagA translocation, suggesting a specific feature associated with HopQ mediated binding.
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Hurlow J, Blanz E, Gaddy JA. Clinical investigation of biofilm in non-healing wounds by high resolution microscopy techniques. J Wound Care 2018; 25 Suppl 9:S11-22. [PMID: 27608736 DOI: 10.12968/jowc.2016.25.sup9.s11] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE The aim of this study was to analyse wound biofilm from a clinical perspective. Research has shown that biofilm is the preferred microbial phenotype in health and disease and is present in a majority of chronic wounds. Biofilm has been linked to chronic wound inflammation, impairment in granulation tissue and epithelial migration, yet there lacks the ability to confirm the clinical presence of biofilm. This study links the clinical setting with microscopic laboratory confirmation of the presence of biofilm in carefully selected wound debridement samples. METHOD Human wound debridement samples were collected from adult patients with chronic non-healing wounds who presented at the wound care centre. Sample choice was guided by an algorithm that was developed based on what is known about the characteristics of wound biofilm. The samples were then evaluated by light microscopy and scanning electron microscopy for the presence of biofilm. Details about subject history and treatment were recorded. Adherence to biofilm-based wound care (BBWC) strategies was inconsistent. Other standard antimicrobial dressings were used and no modern antiseptic wound dressings with the addition of proven antibiofilm agents were available for use. RESULTS Of the patients recruited, 75% of the macroscopic samples contained biofilm despite the prior use of modern antiseptic wound dressings and in some cases, systemic antibiotics. Wounds found to contain biofilm were not all acutely infected but biofilm was present when infection was noted. The clinical histories associated with positive samples were consistent with ideas presented in the algorithm used to guide sample selection. CONCLUSION Visual cues can be used by the clinician to guide suspicion of the presence of wound biofilm. This suspicion can be further enhanced with the use of a clinical algorithm. Standard antiseptic wound dressings used in this study demonstrated limited antibiofilm efficacy. This study also highlighted a need for the clinical team to focus on expiration of dressing action and consistent practice of BBWC strategies which includes the use of proven antibiofilm agents.
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Affiliation(s)
- J Hurlow
- Association for the Advancement of Wound Care (AAWC) Board of Directors, Wound Care LLC, Memphis, Tennessee, US
| | - E Blanz
- Tennessee Valley Healthcare System, Department of Veterans Affairs, Nashville, Tennessee, US
| | - J A Gaddy
- Tennessee Valley Healthcare System, Department of Veterans Affairs, Nashville, Tennessee, US.,Vanderbilt University Medical Center, Department of Medicine, Nashville, Tennessee, US
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Yuan XY, Wang Y, Wang MY. The type IV secretion system in Helicobacter pylori. Future Microbiol 2018; 13:1041-1054. [PMID: 29927340 DOI: 10.2217/fmb-2018-0038] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Helicobacter pylori (H. pylori) has an essential role in the pathogenesis of gastritis, peptic ulcer disease, mucosa-associated lymphoid tissue lymphoma and gastric cancer. The severity of the host inflammatory responses against the bacteria have been straightly associated with a special bacterial virulence factor, the cag pathogenicity island, which is a type IV secretion system (T4SS) to deliver CagA into the host cells. Besides cag-T4SS, the chromosomes of H. pylori can encode another three T4SSs, including comB, tfs3 and tfs4. In this review, we systematically reviewed the four T4SSs of H. pylori and explored their roles in the pathogenesis of gastroduodenal diseases. The information summarized in this review might provide valuable insights into the pathogenic mechanism for H. pylori.
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Affiliation(s)
- Xiao-Yan Yuan
- Department of Central Lab, Weihai Municipal Hospital Affiliated to Dalian Medical University, Weihai, Shandong, 264200, PR China
| | - Ying Wang
- Department of Central Lab, Weihai Municipal Hospital Affiliated to Dalian Medical University, Weihai, Shandong, 264200, PR China
| | - Ming-Yi Wang
- Department of Central Lab, Weihai Municipal Hospital Affiliated to Dalian Medical University, Weihai, Shandong, 264200, PR China
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CagY-Dependent Regulation of Type IV Secretion in Helicobacter pylori Is Associated with Alterations in Integrin Binding. mBio 2018; 9:mBio.00717-18. [PMID: 29764950 PMCID: PMC5954226 DOI: 10.1128/mbio.00717-18] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Strains of Helicobacter pylori that cause ulcer or gastric cancer typically express a type IV secretion system (T4SS) encoded by the cag pathogenicity island (cagPAI). CagY is an ortholog of VirB10 that, unlike other VirB10 orthologs, has a large middle repeat region (MRR) with extensive repetitive sequence motifs, which undergo CD4+ T cell-dependent recombination during infection of mice. Recombination in the CagY MRR reduces T4SS function, diminishes the host inflammatory response, and enables the bacteria to colonize at a higher density. Since CagY is known to bind human α5β1 integrin, we tested the hypothesis that recombination in the CagY MRR regulates T4SS function by modulating binding to α5β1 integrin. Using a cell-free microfluidic assay, we found that H. pylori binding to α5β1 integrin under shear flow is dependent on the CagY MRR, but independent of the presence of the T4SS pili, which are only formed when H. pylori is in contact with host cells. Similarly, expression of CagY in the absence of other T4SS genes was necessary and sufficient for whole bacterial cell binding to α5β1 integrin. Bacteria with variant cagY alleles that reduced T4SS function showed comparable reduction in binding to α5β1 integrin, although CagY was still expressed on the bacterial surface. We speculate that cagY-dependent modulation of H. pylori T4SS function is mediated by alterations in binding to α5β1 integrin, which in turn regulates the host inflammatory response so as to maximize persistent infection.IMPORTANCE Infection with H. pylori can cause peptic ulcers and is the most important risk factor for gastric cancer, the third most common cause of cancer death worldwide. The major H. pylori virulence factor that determines whether infection causes disease or asymptomatic colonization is the type IV secretion system (T4SS), a sort of molecular syringe that injects bacterial products into gastric epithelial cells and alters host cell physiology. We previously showed that recombination in CagY, an essential T4SS component, modulates the function of the T4SS. Here we found that these recombination events produce parallel changes in specific binding to α5β1 integrin, a host cell receptor that is essential for T4SS-dependent translocation of bacterial effectors. We propose that CagY-dependent binding to α5β1 integrin acts like a molecular rheostat that alters T4SS function and modulates the host immune response to promote persistent infection.
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Backert S, Haas R, Gerhard M, Naumann M. The Helicobacter pylori Type IV Secretion System Encoded by the cag Pathogenicity Island: Architecture, Function, and Signaling. Curr Top Microbiol Immunol 2018. [DOI: 10.1007/978-3-319-75241-9_8] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Bats SH, Bergé C, Coombs N, Terradot L, Josenhans C. Biochemical characterization of the Helicobacter pylori Cag Type 4 Secretion System protein CagN and its interaction partner CagM. Int J Med Microbiol 2018; 308:425-437. [PMID: 29572102 DOI: 10.1016/j.ijmm.2018.02.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 02/22/2018] [Accepted: 02/25/2018] [Indexed: 12/26/2022] Open
Abstract
Highly virulent Helicobacter pylori strains contain the cag pathogenicity island (cagPAI). It codes for about 30 proteins forming a type IV secretion system (T4SS) which translocates the pro-inflammatory protein CagA into epithelial host cells. While CagA and various other Cag proteins have been extensively studied, several cagPAI proteins are poorly characterized or of unknown function. CagN (HP0538) is of unknown function but highly conserved in the cagPAI suggesting an important role. cagM (HP0537) is the first gene of the cagMN operon and its product is part of the CagT4SS core complex. Both proteins do not have detectable homologs in other type IV secretion systems. We have characterized the biochemical and structural properties of CagN and CagM and their interaction. We demonstrate by circular dichroism, Multi-Angle Light Scattering (MALS) and small angle X-ray scattering (SAXS) that CagN is a folded, predominantly monomeric protein with an elongated shape in solution. CagM is folded and forms predominantly dimers that are also elongated in solution. We found by various in vivo and in vitro methods that CagN and CagM directly interact with each other. CagM self-interacts stably with a low nanomolar KD and can form stable multimers. Finally, in vivo experiments show that deletion of CagM reduces the amounts of CagN and other outer CagPAI proteins in H. pylori cells.
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Affiliation(s)
- Simon H Bats
- Institut für Medizinische Mikrobiologie und Krankenhaushygiene, Medizinische Hochschule Hannover, Carl-Neuberg-Straße 1, 30625 Hannover, Germany; Max von Pettenkofer Institute, Ludwig Maximilians Universität LMU München, Pettenkoferstraße 9a, 80336 München, Germany
| | - Célia Bergé
- UMR 5086 Molecular Microbiology and Structural Biochemistry CNRS-Université de Lyon 1, Institut de Biologie et Chimie des Protéines, 7 Passage du Vercors, 69367 Lyon, Cedex 07, France
| | - Nina Coombs
- Institut für Medizinische Mikrobiologie und Krankenhaushygiene, Medizinische Hochschule Hannover, Carl-Neuberg-Straße 1, 30625 Hannover, Germany; German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Germany; German Center for Infection Research (DZIF), Partner Site Munich, Germany
| | - Laurent Terradot
- UMR 5086 Molecular Microbiology and Structural Biochemistry CNRS-Université de Lyon 1, Institut de Biologie et Chimie des Protéines, 7 Passage du Vercors, 69367 Lyon, Cedex 07, France
| | - Christine Josenhans
- Institut für Medizinische Mikrobiologie und Krankenhaushygiene, Medizinische Hochschule Hannover, Carl-Neuberg-Straße 1, 30625 Hannover, Germany; Max von Pettenkofer Institute, Ludwig Maximilians Universität LMU München, Pettenkoferstraße 9a, 80336 München, Germany; German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Germany; German Center for Infection Research (DZIF), Partner Site Munich, Germany.
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Tafreshi M, Guan J, Gorrell RJ, Chew N, Xin Y, Deswaerte V, Rohde M, Daly RJ, Peek RM, Jenkins BJ, Davies EM, Kwok T. Helicobacter pylori Type IV Secretion System and Its Adhesin Subunit, CagL, Mediate Potent Inflammatory Responses in Primary Human Endothelial Cells. Front Cell Infect Microbiol 2018; 8:22. [PMID: 29468142 PMCID: PMC5808116 DOI: 10.3389/fcimb.2018.00022] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Accepted: 01/16/2018] [Indexed: 12/20/2022] Open
Abstract
The Gram-negative bacterium, Helicobacter pylori, causes chronic gastritis, peptic ulcers, and gastric cancer in humans. Although the gastric epithelium is the primary site of H. pylori colonization, H. pylori can gain access to deeper tissues. Concurring with this notion, H. pylori has been found in the vicinity of endothelial cells in gastric submucosa. Endothelial cells play crucial roles in innate immune response, wound healing and tumorigenesis. This study examines the molecular mechanisms by which H. pylori interacts with and triggers inflammatory responses in endothelial cells. We observed that H. pylori infection of primary human endothelial cells stimulated secretion of the key inflammatory cytokines, interleukin-6 (IL-6) and interleukin-8 (IL-8). In particular, IL-8, a potent chemokine and angiogenic factor, was secreted by H. pylori-infected endothelial cells to levels ~10- to 20-fold higher than that typically observed in H. pylori-infected gastric epithelial cells. These inflammatory responses were triggered by the H. pylori type IV secretion system (T4SS) and the T4SS-associated adhesin CagL, but not the translocation substrate CagA. Moreover, in contrast to integrin α5β1 playing an essential role in IL-8 induction by H. pylori upon infection of gastric epithelial cells, both integrin α5β1 and integrin αvβ3 were dispensable for IL-8 induction in H. pylori-infected endothelial cells. However, epidermal growth factor receptor (EGFR) is crucial for mediating the potent H. pylori-induced IL-8 response in endothelial cells. This study reveals a novel mechanism by which the H. pylori T4SS and its adhesin subunit, CagL, may contribute to H. pylori pathogenesis by stimulating the endothelial innate immune responses, while highlighting EGFR as a potential therapeutic target for controlling H. pylori-induced inflammation.
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Affiliation(s)
- Mona Tafreshi
- Infection & Immunity Program, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
| | - Jyeswei Guan
- Infection & Immunity Program, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
| | - Rebecca J. Gorrell
- Infection & Immunity Program, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
- Cancer Program, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
- Infection & Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC, Australia
| | - Nicole Chew
- Cancer Program, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
| | - Yue Xin
- Infection & Immunity Program, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
| | - Virginie Deswaerte
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia
- Department of Molecular Translational Science, School of Clinical Sciences, Monash University, Clayton, VIC, Australia
| | - Manfred Rohde
- Helmholtz Centre for Infection Research, Central Facility for Microscopy, Braunschweig, Germany
| | - Roger J. Daly
- Cancer Program, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
| | - Richard M. Peek
- Division of Gastroenterology, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Brendan J. Jenkins
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia
- Department of Molecular Translational Science, School of Clinical Sciences, Monash University, Clayton, VIC, Australia
| | - Elizabeth M. Davies
- Cancer Program, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
| | - Terry Kwok
- Infection & Immunity Program, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
- Cancer Program, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
- Infection & Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC, Australia
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Kim SH, Lee MH, Park M, Woo HJ, Kim YS, Tharmalingam N, Seo WD, Kim JB. Regulatory Effects of Black Rice Extract on Helicobacter pylori Infection-Induced Apoptosis. Mol Nutr Food Res 2017; 62. [PMID: 29035012 DOI: 10.1002/mnfr.201700586] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 09/28/2017] [Indexed: 12/12/2022]
Abstract
SCOPE Black rice extract (BRE) contains cyanidin 3-O-glucoside (C3G), an anthocyanin, as the major component. In this study, we found that BRE inhibits the mRNA and protein expression of genes encoding cytotoxin-associated protein A (cagA) and vacuolating protein A (vacA) in Helicobacter pylori 60190 strain. METHODS AND RESULTS We performed RT-PCR and western blotting to show that BRE inhibits the mRNA and protein expression of SecA. Because SecA is involved in VacA export in bacteria, our result suggests a positive correlation between BRE-induced inhibition of secA expression and VacA secretion. Further, we perform MTT assay and flow cytometry to show that BRE decreases the apoptosis of H. pylori-infected KATO III cells. Finally, we perform western blotting to show that the cell-protective effect of BRE is associated with decreased levels of active proapoptotic proteins caspases and PARP and increased levels of antiapoptotic proteins survivin and XIAP in H. pylori-infected cells. CONCLUSION Thus, our results indicate that BRE acts as a potent inhibitor of the biogenesis of H. pylori virulence proteins and decreases the apoptosis of H. pylori-infected cells. Moreover, our results suggest that BRE can be used to exert beneficial effects in patients with gastroduodenal diseases caused by H. pylori.
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Affiliation(s)
- Sa-Hyun Kim
- Department of Clinical Laboratory Science, Semyung University, Jecheon, Republic of Korea
| | - Min Ho Lee
- Department of Biomedical Laboratory Science, College of Health Sciences, Yonsei University, Wonju, Republic of Korea
| | - Min Park
- Department of Biomedical Laboratory Science, Daekyeung University, Gyeongsan, Republic of Korea
| | - Hyun Jun Woo
- Department of Biomedical Laboratory Science, College of Health Sciences, Yonsei University, Wonju, Republic of Korea
| | - Yoon Suk Kim
- Department of Biomedical Laboratory Science, College of Health Sciences, Yonsei University, Wonju, Republic of Korea
| | - Nagendran Tharmalingam
- Division of Infectious Diseases, Department of Medicine, Rhode Island Hospital, Alpert Medical School of Brown University, Providence, RI, USA
| | - Woo-Duck Seo
- Crop Foundation Division, National Institute of Crop Science, Jeollabuk-do, Republic of Korea
| | - Jong-Bae Kim
- Department of Biomedical Laboratory Science, College of Health Sciences, Yonsei University, Wonju, Republic of Korea
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Electron microscopic observations of prokaryotic surface appendages. J Microbiol 2017; 55:919-926. [DOI: 10.1007/s12275-017-7369-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 10/10/2017] [Accepted: 10/15/2017] [Indexed: 12/21/2022]
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Koelblen T, Bergé C, Cherrier MV, Brillet K, Jimenez-Soto L, Ballut L, Takagi J, Montserret R, Rousselle P, Fischer W, Haas R, Fronzes R, Terradot L. Molecular dissection of protein-protein interactions between integrin α5β1 and the Helicobacter pylori
Cag type IV secretion system. FEBS J 2017; 284:4143-4157. [DOI: 10.1111/febs.14299] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 10/04/2017] [Accepted: 10/17/2017] [Indexed: 12/31/2022]
Affiliation(s)
- Thomas Koelblen
- UMR 5086 Molecular Microbiology and Structural Biochemistry; Institut de Biologie et Chimie des Protéines; CNRS-Université de Lyon; France
| | - Célia Bergé
- UMR 5086 Molecular Microbiology and Structural Biochemistry; Institut de Biologie et Chimie des Protéines; CNRS-Université de Lyon; France
| | - Mickaël V. Cherrier
- UMR 5086 Molecular Microbiology and Structural Biochemistry; Institut de Biologie et Chimie des Protéines; CNRS-Université de Lyon; France
| | - Karl Brillet
- UMR 5086 Molecular Microbiology and Structural Biochemistry; Institut de Biologie et Chimie des Protéines; CNRS-Université de Lyon; France
| | - Luisa Jimenez-Soto
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie; Ludwig-Maximilians-Universität; München Germany
| | - Lionel Ballut
- UMR 5086 Molecular Microbiology and Structural Biochemistry; Institut de Biologie et Chimie des Protéines; CNRS-Université de Lyon; France
| | - Junichi Takagi
- Laboratory of Protein Synthesis and Expression; Institute for Protein Research; Osaka University; Japan
| | - Roland Montserret
- UMR 5086 Molecular Microbiology and Structural Biochemistry; Institut de Biologie et Chimie des Protéines; CNRS-Université de Lyon; France
| | - Patricia Rousselle
- Laboratoire de Biologie Tissulaire et Ingénierie Thérapeutique; UMR 5305; CNRS; University Lyon 1; France
| | - Wolfgang Fischer
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie; Ludwig-Maximilians-Universität; München Germany
| | - Rainer Haas
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie; Ludwig-Maximilians-Universität; München Germany
- German Center for Infection Research (DZIF); Partner Site LMU; München Germany
| | - Rémi Fronzes
- European Institute of Chemistry and Biology; CNRS; UMR 5234; Microbiologie Fondamentale et Pathogénicité; University of Bordeaux; Pessac France
| | - Laurent Terradot
- UMR 5086 Molecular Microbiology and Structural Biochemistry; Institut de Biologie et Chimie des Protéines; CNRS-Université de Lyon; France
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Abstract
Helicobacter pylori is the most common bacterial infection worldwide, and virtually all infected persons develop co-existing gastritis. H. pylori is able to send and receive signals from the gastric mucosa, which enables both host and microbe to engage in a dynamic equilibrium. In order to persist within the human host, H. pylori has adopted dichotomous strategies to both induce inflammation as a means of liberating nutrients while simultaneously tempering the immune response to augment its survival. Toll-like receptors (TLRs) and Nod proteins are innate immune receptors that are present in epithelial cells and represent the first line of defense against pathogens. To ensure persistence, H. pylori manipulates TLR-mediated defenses using strategies that include rendering its LPS and flagellin to be non-stimulatory to TLR4 and TLR5, respectively; translocating peptidoglycan into host cells to induce NOD1-mediated anti-inflammatory responses; and translocating DNA into host cells to induce TLR9 activation.
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Structural Insights into Helicobacter pylori Cag Protein Interactions with Host Cell Factors. Curr Top Microbiol Immunol 2017; 400:129-147. [PMID: 28124152 DOI: 10.1007/978-3-319-50520-6_6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The most virulent strains of Helicobacter pylori carry a genomic island (cagPAI) containing a set of 27-31 genes. The encoded proteins assemble a syringe-like apparatus to inject the cytotoxin-associated gene A (CagA) protein into gastric cells. This molecular device belongs to the type IV secretion system (T4SS) family albeit with unique characteristics. The cagPAI-encoded T4SS and its effector protein CagA have an intricate relationship with the host cell, with multiple interactions that only start to be deciphered from a structural point of view. On the one hand, the major roles of the interactions between CagL and CagA (and perhaps CagI and CagY) and host cell factors are to facilitate H. pylori adhesion and to mediate the injection of the CagA oncoprotein. On the other hand, CagA interactions with host cell partners interfere with cellular pathways to subvert cell defences and to promote H. pylori infection. Although a clear mechanism for CagA translocation is still lacking, the structural definition of CagA and CagL domains involved in interactions with signalling proteins are progressively coming to light. In this chapter, we will focus on the structural aspects of Cag protein interactions with host cell molecules, critical molecular events precluding H. pylori-mediated gastric cancer development.
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Cherati MR, Shokri-Shirvani J, Karkhah A, Rajabnia R, Nouri HR. Helicobacter pylori cagL amino acid polymorphism D58E59 pave the way toward peptic ulcer disease while N58E59 is associated with gastric cancer in north of Iran. Microb Pathog 2017; 107:413-418. [DOI: 10.1016/j.micpath.2017.04.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 04/12/2017] [Accepted: 04/19/2017] [Indexed: 02/07/2023]
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Kumar N, Shariq M, Kumar A, Kumari R, Subbarao N, Tyagi RK, Mukhopadhyay G. Analyzing the role of CagV, a VirB8 homolog of the type IV secretion system of Helicobacter pylori. FEBS Open Bio 2017; 7:915-933. [PMID: 28680806 PMCID: PMC5494299 DOI: 10.1002/2211-5463.12225] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 02/22/2017] [Accepted: 02/24/2017] [Indexed: 12/13/2022] Open
Abstract
The type IV secretion system of Helicobacter pylori (Cag‐T4SS) is composed of ~ 27 components including a VirB8 homolog, CagV. We have characterized CagV and reported that it is an inner membrane protein and, like VirB8, forms a homodimer. Its stability is not dependent on the other Cag components and the absence of cagV affects the stability of only CagI, a protein involved in pilus formation. CagV is not required for the stability and localization of outer membrane subcomplex proteins, but interacts with them through CagX. It also interacts with the inner membrane‐associated components, CagF and CagZ, and is required for the surface localization of CagA. The results of this study might help in deciphering the mechanistic contributions of CagV in the Cag‐T4SS biogenesis and function.
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Affiliation(s)
- Navin Kumar
- Special Centre for Molecular Medicine Jawaharlal Nehru University New Delhi India.,Present address: School of Biotechnology Gautam Buddha University Yamuna Expressway Greater Noida Gautam Budh Nagar Uttar Pradesh India
| | - Mohd Shariq
- Special Centre for Molecular Medicine Jawaharlal Nehru University New Delhi India.,Present address: School of Life Sciences Jawaharlal Nehru University New Delhi India
| | - Amarjeet Kumar
- School of Computational and Integrative Sciences Jawaharlal Nehru University New Delhi India
| | - Rajesh Kumari
- Special Centre for Molecular Medicine Jawaharlal Nehru University New Delhi India
| | - Naidu Subbarao
- School of Computational and Integrative Sciences Jawaharlal Nehru University New Delhi India
| | - Rakesh K Tyagi
- Special Centre for Molecular Medicine Jawaharlal Nehru University New Delhi India
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