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Danov A, Pollin I, Moon E, Ho M, Wilson BA, Papathanos PA, Kaplan T, Levy A. Identification of novel toxins associated with the extracellular contractile injection system using machine learning. Mol Syst Biol 2024; 20:859-879. [PMID: 39069594 PMCID: PMC11297309 DOI: 10.1038/s44320-024-00053-6] [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: 01/24/2024] [Revised: 06/06/2024] [Accepted: 06/27/2024] [Indexed: 07/30/2024] Open
Abstract
Secretion systems play a crucial role in microbe-microbe or host-microbe interactions. Among these systems, the extracellular contractile injection system (eCIS) is a unique bacterial and archaeal extracellular secretion system that injects protein toxins into target organisms. However, the specific proteins that eCISs inject into target cells and their functions remain largely unknown. Here, we developed a machine learning classifier to identify eCIS-associated toxins (EATs). The classifier combines genetic and biochemical features to identify EATs. We also developed a score for the eCIS N-terminal signal peptide to predict EAT loading. Using the classifier we classified 2,194 genes from 950 genomes as putative EATs. We validated four new EATs, EAT14-17, showing toxicity in bacterial and eukaryotic cells, and identified residues of their respective active sites that are critical for toxicity. Finally, we show that EAT14 inhibits mitogenic signaling in human cells. Our study provides insights into the diversity and functions of EATs and demonstrates machine learning capability of identifying novel toxins. The toxins can be employed in various applications dependently or independently of eCIS.
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Affiliation(s)
- Aleks Danov
- Department of Plant Pathology and Microbiology, Institute of Environmental Sciences, The Robert H. Smith Faculty of Agriculture, Food & Environment, The Hebrew University of Jerusalem, Rehovot, 7610001, Israel
| | - Inbal Pollin
- Department of Plant Pathology and Microbiology, Institute of Environmental Sciences, The Robert H. Smith Faculty of Agriculture, Food & Environment, The Hebrew University of Jerusalem, Rehovot, 7610001, Israel
| | - Eric Moon
- Department of Microbiology, University of Illinois Urbana-Champaign, 601 South Goodwin Ave, Urbana, 61801, IL, USA
| | - Mengfei Ho
- Department of Microbiology, University of Illinois Urbana-Champaign, 601 South Goodwin Ave, Urbana, 61801, IL, USA
| | - Brenda A Wilson
- Department of Microbiology, University of Illinois Urbana-Champaign, 601 South Goodwin Ave, Urbana, 61801, IL, USA
| | - Philippos A Papathanos
- Department of Entomology, Institute of Environmental Sciences, The Robert H. Smith Faculty of Agriculture, Food & Environment, The Hebrew University of Jerusalem, Rehovot, 7610001, Israel
| | - Tommy Kaplan
- School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel
- Department of Developmental Biology and Cancer Research, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Asaf Levy
- Department of Plant Pathology and Microbiology, Institute of Environmental Sciences, The Robert H. Smith Faculty of Agriculture, Food & Environment, The Hebrew University of Jerusalem, Rehovot, 7610001, Israel.
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2
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Mok CY, Chu HY, Lam WWL, Au SWN. Structural insights into the assembly pathway of the Helicobacter pylori CagT4SS outer membrane core complex. Structure 2024:S0969-2126(24)00237-5. [PMID: 39032488 DOI: 10.1016/j.str.2024.06.019] [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: 03/14/2024] [Revised: 05/16/2024] [Accepted: 06/25/2024] [Indexed: 07/23/2024]
Abstract
Cag type IV secretion system (CagT4SS) translocates oncoprotein cytotoxin-associated gene A (CagA) into host cells and plays a key role in the pathogenesis of Helicobacter pylori. The structure of the outer membrane core complex (OMCC) in CagT4SS consists of CagX, CagY, CagM, CagT, and Cag3 in a stoichiometric ratio of 1:1:2:2:5 with 14-fold symmetry. However, the assembly pathway of OMCC remains elusive. Here, we report the crystal structures of CagT and Cag3-CagT complex, and the structural dynamics of Cag3 and CagT using hydrogen deuterium exchange-mass spectrometry (HDX-MS). The interwoven interaction of Cag3 and CagT involves conformational changes of CagT and β strand swapping. In conjunction with biochemical and biophysical assays, we further demonstrate the different oligomerization states of Cag3 and Cag3-CagT complex. Additionally, the association with CagM requires the pre-formation of Cag3-CagT complex. These results demonstrate the generation of different intermediate sub-assemblies and their structural flexibility, potentially representing different building blocks for OMCC assembly.
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Affiliation(s)
- Chin Yu Mok
- Center for Protein Science and Crystallography, School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Hoi Yee Chu
- Center for Protein Science and Crystallography, School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Wendy Wai Ling Lam
- Center for Protein Science and Crystallography, School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Shannon Wing Ngor Au
- Center for Protein Science and Crystallography, School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
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3
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Zehra M, Heo J, Chung JM, Durie CL. Comparative Analysis of T4SS Molecular Architectures. J Microbiol Biotechnol 2023; 33:1543-1551. [PMID: 37528551 PMCID: PMC10772558 DOI: 10.4014/jmb.2307.07006] [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: 07/06/2023] [Revised: 07/21/2023] [Accepted: 07/24/2023] [Indexed: 08/03/2023]
Abstract
The recently published high-resolution R388 T4SS structure provides exciting new details about the complete complex of T4SS, including the components making up the stalk and arches, numerous symmetry mismatches between regions of the complex, and an intriguing interpretation of the closed stalk and radial symmetry of the inner membrane complex, which is related to pilus biogenesis assembly. However, there are a few unidentified densities in the electron microscopy map and portions of the identified component sequences for which the structure is not yet known. It is also unclear how well this minimized DNA-transporting T4SS predicts the structure of other T4SSs, such as expanded systems and those that transport proteins rather than DNA. In this review, we evaluate what can be inferred from the recent high-resolution structure of the R388 T4SS with respect to the Cag and Dot/Icm systems. These systems were selected because, given what is currently known about these systems, we expect them to present most structural differences compared to the R388 T4SS structure. Furthermore, we discuss bacterial physiology and diversity, the T4SS structures and their variations between different bacterial species. These insights may prove beneficial for researchers who elucidate the structure and functions of T4SS in different bacterial species.
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Affiliation(s)
- Mishghan Zehra
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
| | - Jiwon Heo
- Department of Biotechnology, The Catholic University of Korea, Bucheon-si 14662, Gyeonggi, Republic of Korea
| | - Jeong Min Chung
- Department of Biotechnology, The Catholic University of Korea, Bucheon-si 14662, Gyeonggi, Republic of Korea
| | - Clarissa L Durie
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
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4
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Gabbert AD, Mydosh JL, Talukdar PK, Gloss LM, McDermott JE, Cooper KK, Clair GC, Konkel ME. The Missing Pieces: The Role of Secretion Systems in Campylobacter jejuni Virulence. Biomolecules 2023; 13:135. [PMID: 36671522 PMCID: PMC9856085 DOI: 10.3390/biom13010135] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 12/29/2022] [Accepted: 01/05/2023] [Indexed: 01/10/2023] Open
Abstract
Campylobacter jejuni is likely the most common bacterial cause of gastroenteritis worldwide, responsible for millions of cases of inflammatory diarrhea characterized by severe abdominal cramps and blood in the stool. Further, C. jejuni infections are associated with post-infection sequelae in developed countries and malnutrition and growth-stunting in low- and middle-income countries. Despite the increasing prevalence of the disease, campylobacteriosis, and the recognition that this pathogen is a serious health threat, our understanding of C. jejuni pathogenesis remains incomplete. In this review, we focus on the Campylobacter secretion systems proposed to contribute to host-cell interactions and survival in the host. Moreover, we have applied a genomics approach to defining the structural and mechanistic features of C. jejuni type III, IV, and VI secretion systems. Special attention is focused on the flagellar type III secretion system and the prediction of putative effectors, given that the proteins exported via this system are essential for host cell invasion and the inflammatory response. We conclude that C. jejuni does not possess a type IV secretion system and relies on the type III and type VI secretion systems to establish a niche and potentiate disease.
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Affiliation(s)
- Amber D. Gabbert
- School of Molecular Biosciences, College of Veterinary Sciences, Washington State University, Pullman, WA 99164, USA
| | - Jennifer L. Mydosh
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, AZ 85721, USA
| | - Prabhat K. Talukdar
- School of Molecular Biosciences, College of Veterinary Sciences, Washington State University, Pullman, WA 99164, USA
| | - Lisa M. Gloss
- School of Molecular Biosciences, College of Veterinary Sciences, Washington State University, Pullman, WA 99164, USA
| | - Jason E. McDermott
- Integrative Omics, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Kerry K. Cooper
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, AZ 85721, USA
| | - Geremy C. Clair
- Integrative Omics, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Michael E. Konkel
- School of Molecular Biosciences, College of Veterinary Sciences, Washington State University, Pullman, WA 99164, USA
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Evodiamine Inhibits Helicobacter pylori Growth and Helicobacter pylori-Induced Inflammation. Int J Mol Sci 2021; 22:ijms22073385. [PMID: 33806161 PMCID: PMC8036659 DOI: 10.3390/ijms22073385] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/22/2021] [Accepted: 03/23/2021] [Indexed: 12/13/2022] Open
Abstract
Helicobacter pylori (H. pylori) classified as a class I carcinogen by the World Health Organization (WHO) plays an important role in the progression of chronic gastritis and the development of gastric cancer. A major bioactive component of Evodia rutaecarpa, evodiamine, has been known for its anti-bacterial effect and anti-cancer effects. However, the inhibitory effect of evodiamine against H. pylori is not yet known and the inhibitory mechanisms of evodiamine against gastric cancer cells are yet to be elucidated concretely. In this study, therefore, anti-bacterial effect of evodiamine on H. pylori growth and its inhibitory mechanisms as well as anti-inflammatory effects and its mechanisms of evodiamine on H. pylori-induced inflammation were investigated in vitr. Results of this study showed the growth of the H. pylori reference strains and clinical isolates were inhibited by evodiamine. It was considered one of the inhibitory mechanisms that evodiamine downregulated both gene expressions of replication and transcription machineries of H. pylori. Treatment of evodiamine also induced downregulation of urease and diminished translocation of cytotoxin-associated antigen A (CagA) and vacuolating cytotoxin A (VacA) proteins into gastric adenocarcinoma (AGS) cells. This may be resulted from the reduction of CagA and VacA expressions as well as the type IV secretion system (T4SS) components and secretion system subunit protein A (SecA) protein which are involved in translocation of CagA and VacA into host cells, respectively. In particular, evodiamine inhibited the activation of signaling proteins such as the nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) and the mitogen-activated protein kinase (MAPK) pathway induced by H. pylori infection. It consequently might contribute to reduction of interleukin (IL)-8 production in AGS cells. Collectively, these results suggest anti-bacterial and anti-inflammatory effects of evodiamine against H. pylori.
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Rizzato C, Torres J, Obazee O, Camorlinga-Ponce M, Trujillo E, Stein A, Mendez-Tenorio A, Bravo MM, Canzian F, Kato I. Variations in cag pathogenicity island genes of Helicobacter pylori from Latin American groups may influence neoplastic progression to gastric cancer. Sci Rep 2020; 10:6570. [PMID: 32300197 PMCID: PMC7162905 DOI: 10.1038/s41598-020-63463-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 03/20/2020] [Indexed: 12/11/2022] Open
Abstract
Helicobacter pylori (HP) colonizes the human stomach and induces acute gastritis, peptic ulcer disease, atrophic gastritis, and gastric adenocarcinoma. Increased virulence in HP isolates derives from harboring the cag (cytotoxin-associated genes) pathogenicity island (cagPAI). We analyzed the microvariants in cagPAI genes with the hypothesis that they may play an important role in determining HP virulence. We tested DNAs from cagA positive patients HP isolates; a total of 74 patients with chronic gastritis (CG, N = 37), intestinal metaplasia (IM, N = 21) or gastric cancer (GC, N = 16) from Mexico and Colombia. We selected 520 non-synonymous variants with at least 7.5% frequency in the original sequence outputs or with a minimum of 5 isolates with minor allele. After adjustment for multiple comparisons, no variants were statistically significantly associated with IM or GC. However, 19 non-synonymous showed conventional P-values < 0.05 comparing the frequency of the alleles between the isolates from subjects with gastritis and isolates from subjects with IM or GC; 12 of these showed a significant correlation with the severity of the disease. The present study revealed that several cagPAI genes from Latin American Western HP strains contains a number of non-synonymous variants in relatively high frequencies which could influence on the clinical outcome. However, none of the associations remained statistically significant after adjustment for multiple comparison.
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Affiliation(s)
- Cosmeri Rizzato
- Department of Translation Research and of New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy.
| | - Javier Torres
- Unidad de Investigación en Enfermedades Infecciosas, UMAE Pediatría, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Ofure Obazee
- Genomic Epidemiology Group, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Margarita Camorlinga-Ponce
- Unidad de Investigación en Enfermedades Infecciosas, UMAE Pediatría, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Esperanza Trujillo
- Grupo de Investigación en Biología del Cáncer. Instituto Nacional de Cancerología, Bogotá, Colombia
| | - Angelika Stein
- Genomic Epidemiology Group, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Alfonso Mendez-Tenorio
- Laboratorio de Biotecnología y Bioinformática Genómica, ENCB, Instituto Politécnico Nacional, México City, México
| | - Maria Mercedes Bravo
- Grupo de Investigación en Biología del Cáncer. Instituto Nacional de Cancerología, Bogotá, Colombia
| | - Federico Canzian
- Genomic Epidemiology Group, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Ikuko Kato
- Department of Oncology and Pathology, Wayne State University School of Medicine, Detroit, MI, USA
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7
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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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8
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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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Christie PJ, Gomez Valero L, Buchrieser C. Biological Diversity and Evolution of Type IV Secretion Systems. Curr Top Microbiol Immunol 2019; 413:1-30. [PMID: 29536353 PMCID: PMC5912172 DOI: 10.1007/978-3-319-75241-9_1] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The bacterial type IV secretion systems (T4SSs) are a highly functionally and structurally diverse superfamily of secretion systems found in many species of Gram-negative and -positive bacteria. Collectively, the T4SSs can translocate DNA and monomeric and multimeric protein substrates to a variety of bacterial and eukaryotic cell types. Detailed phylogenomics analyses have established that the T4SSs evolved from ancient conjugation machines whose original functions were to disseminate mobile DNA elements within and between bacterial species. How members of the T4SS superfamily evolved to recognize and translocate specific substrate repertoires to prokaryotic or eukaryotic target cells is a fascinating question from evolutionary, biological, and structural perspectives. In this chapter, we will summarize recent findings that have shaped our current view of the biological diversity of the T4SSs. We focus mainly on two subtypes, designated as the types IVA (T4ASS) and IVB (T4BSS) systems that respectively are represented by the paradigmatic Agrobacterium tumefaciens VirB/VirD4 and Legionella pneumophila Dot/Icm T4SSs. We present current information about the composition and architectures of these representative systems. We also describe how these and a few related T4ASS and T4BSS members evolved as specialized nanomachines through acquisition of novel domains or subunits, a process that ultimately generated extensive genetic and structural mosaicism among this secretion superfamily. Finally, we present new phylogenomics information establishing that the T4BSSs are much more broadly distributed than initially envisioned.
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Affiliation(s)
- Peter J Christie
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, TX, 77030, USA.
| | - Laura Gomez Valero
- Institut Pasteur, Biologie des Bactéries Intracellulaires, 75724, Paris, France
- CNRS, UMR 3525, 75724, Paris, France
| | - Carmen Buchrieser
- Institut Pasteur, Biologie des Bactéries Intracellulaires, 75724, Paris, France
- CNRS, UMR 3525, 75724, Paris, France
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10
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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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Lee MH, Yang JY, Cho Y, Woo HJ, Kwon HJ, Kim DH, Park M, Moon C, Yeon MJ, Kim HW, Seo WD, Kim SH, Kim JB. Inhibitory Effects of Menadione on Helicobacter pylori Growth and Helicobacter pylori-Induced Inflammation via NF-κB Inhibition. Int J Mol Sci 2019; 20:ijms20051169. [PMID: 30866458 PMCID: PMC6429389 DOI: 10.3390/ijms20051169] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 03/01/2019] [Accepted: 03/04/2019] [Indexed: 12/19/2022] Open
Abstract
H. pylori is classified as a group I carcinogen by WHO because of its involvement in gastric cancer development. Several reports have suggested anti-bacterial effects of menadione, although the effect of menadione on major virulence factors of H. pylori and H. pylori-induced inflammation is yet to be elucidated. In this study, therefore, we demonstrated that menadione has anti-H. pylori and anti-inflammatory effects. Menadione inhibited growth of H. pylori reference strains and clinical isolates. Menadione reduced expression of vacA in H. pylori, and translocation of VacA protein into AGS (gastric adenocarcinoma cell) was also decreased by menadione treatment. This result was concordant with decreased apoptosis in AGS cells infected with H. pylori. Moreover, cytotoxin-associated protein A (CagA) translocation into H. pylori-infected AGS cells was also decreased by menadione. Menadione inhibited expression of several type IV secretion system (T4SS) components, including virB2, virB7, virB8, and virB10, that are responsible for translocation of CagA into host cells. In particular, menadione inhibited nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) activation and thereby reduced expression of the proinflammatory cytokines such as IL-1β, IL-6, IL-8, and TNF-α in AGS as well as in THP-1 (monocytic leukemia cell) cell lines. Collectively, these results suggest the anti-bacterial and anti-inflammatory effects of menadione against H. pylori.
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Affiliation(s)
- Min Ho Lee
- Department of Biomedical Laboratory Science, College of Health Sciences, Yonsei University, Wonju 26493, Korea.
- Forensic DNA Division, National Forensic Service, Wonju 26460, Korea.
| | - Ji Yeong Yang
- Department of Biomedical Laboratory Science, College of Health Sciences, Yonsei University, Wonju 26493, Korea.
| | - Yoonjung Cho
- Forensic DNA Division, National Forensic Service, Wonju 26460, Korea.
| | - Hyun Jun Woo
- Department of Clinical Laboratory Science, College of Medical Sciences, Daegu Haany University, Gyeongsan 38610, Korea.
| | - Hye Jin Kwon
- Department of Biomedical Laboratory Science, College of Health Sciences, Yonsei University, Wonju 26493, Korea.
| | - Do Hyun Kim
- Department of Biomedical Laboratory Science, College of Health Sciences, Yonsei University, Wonju 26493, Korea.
| | - Min Park
- Department of Biomedical Laboratory Science, Daekyeung University, Gyeongsan 38547, Korea.
| | - Cheol Moon
- Department of Clinical Laboratory Science, Semyung University, Jecheon 27136, Korea.
| | - Min Ji Yeon
- Natural Products Research Center, Korea Institute of Science and Technology (KIST) Gangneung 25451, Korea.
| | - Hyun Woo Kim
- Department of Biomedical Laboratory Science, College of Health Sciences, Yonsei University, Wonju 26493, Korea.
| | - Woo-Duck Seo
- National Institute of Crop Science (NICS), Rural Development Administration (RDA), Wanju-Gun 55365, Korea.
| | - Sa-Hyun Kim
- Department of Clinical Laboratory Science, Semyung University, Jecheon 27136, Korea.
| | - Jong-Bae Kim
- Department of Biomedical Laboratory Science, College of Health Sciences, Yonsei University, Wonju 26493, Korea.
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12
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Helicobacter pylori-induced DNA Methylation as an Epigenetic Modulator of Gastric Cancer: Recent Outcomes and Future Direction. Pathogens 2019; 8:pathogens8010023. [PMID: 30781778 PMCID: PMC6471032 DOI: 10.3390/pathogens8010023] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 02/04/2019] [Accepted: 02/11/2019] [Indexed: 02/07/2023] Open
Abstract
Gastric cancer is ranked fifth in cancer list and has the third highest mortality rate. Helicobacter pylori is a class I carcinogen and a predominant etiological factor of gastric cancer. H. pylori infection may induce carcinogenesis via epigenetic alterations in the promoter region of various genes. H. pylori is known to induce hypermethylation-silencing of several tumor suppressor genes in H. pylori-infected cancerous and H. pylori-infected non-cancerous gastric mucosae. This article presents a review of the published literature mainly from the last year 15 years. The topic focuses on H. pylori-induced DNA methylation linked to gastric cancer development. The authors have used MeSH terms "Helicobacter pylori" with "epigenetic," "DNA methylation," in combination with "gastric inflammation", gastritis" and "gastric cancer" to search SCOPUS, PubMed, Ovid, and Web of Science databases. The success of epigenetic drugs such as de-methylating agents in the treatment of certain cancers has led towards new prospects that similar approaches could also be applied against gastric cancer. However, it is very important to understand the role of all the genes that have already been linked to H. pylori-induced DNA methylation in order to in order to evaluate the potential benefits of epigenetic drugs.
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Chmiela M, Walczak N, Rudnicka K. Helicobacter pylori outer membrane vesicles involvement in the infection development and Helicobacter pylori-related diseases. J Biomed Sci 2018; 25:78. [PMID: 30409143 PMCID: PMC6225681 DOI: 10.1186/s12929-018-0480-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 10/24/2018] [Indexed: 02/07/2023] Open
Abstract
Helicobacter pylori - (H. pylori) play a role in the pathogenesis of gastritis, gastric and duodenal ulcers as well as gastric cancer. A possible involvement of outer membrane vesicles (OMVs) produced by H. pylori in the distribution of bacterial antigens through the gastric epithelial barrier and their role in the development of local and systemic host inflammatory and immune responses has been suggested. OMVs contain various biologically active compounds, which internalize into host cells affecting signaling pathways and promoting apoptosis of gastric epithelial and immunocompetent cells. OMVs-associated H. pylori virulence factors may strengthen or downregulate the immune responses leading to disease development. This review describes the biological importance of H. pylori OMVs and their role in the course of H. pylori infections, as well as H. pylori related local and systemic effects.
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Affiliation(s)
- Magdalena Chmiela
- Laboratory of Gastroimmunology, Department of Immunology and Infectious Biology, Faculty of Biology and Environmental Protection, University of Łódź, Banacha 12/16, 90-237, Łódź, Poland
| | - Natalia Walczak
- Laboratory of Gastroimmunology, Department of Immunology and Infectious Biology, Faculty of Biology and Environmental Protection, University of Łódź, Banacha 12/16, 90-237, Łódź, Poland
| | - Karolina Rudnicka
- Laboratory of Gastroimmunology, Department of Immunology and Infectious Biology, Faculty of Biology and Environmental Protection, University of Łódź, Banacha 12/16, 90-237, Łódź, Poland.
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14
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Yeon MJ, Lee MH, Kim DH, Yang JY, Woo HJ, Kwon HJ, Moon C, Kim SH, Kim JB. Anti-inflammatory effects of Kaempferol on Helicobacter pylori-induced inflammation. Biosci Biotechnol Biochem 2018; 83:166-173. [PMID: 30286691 DOI: 10.1080/09168451.2018.1528140] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Inflammation induced by Helicobacter pylori infection related to gastric carcinogenesis. In this study, we have investigated the anti-inflammatory effect and its mechanism of kaempferol in the inflammatory response caused by H. pylori infection in vitro. We found that kaempferol reduced the expression of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-8) and production of IL-8 in AGS cells. In addition, kaempferol suppressed translocation of cytotoxin-associated gene A (CagA) and vacuolating cytotoxin A (VacA) of H. pylori to AGS cells. It was due to decreased transcription of type IV secretion system (T4SS) components involved in CagA injection and secretion system subunit protein A (SecA) of type V secretion system (T5SS) involved in VacA secretion by kaempferol. In conclusion, kaempferol shows the anti-inflammatory effect by suppressing the translocation of CagA and VacA proteins and leading to the down-regulation of pro-inflammatory cytokines. Abbreviations: CagA: cytotoxin-associated gene A; VacA: vacuolating cytotoxin A; T4SS: type IV secretion systems; SecA: secretion system subunit protein A; T5SS: type V secretion system.
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Affiliation(s)
- Min Ji Yeon
- a Department of Biomedical Laboratory Science, College of Health Sciences , Yonsei University , Wonju , Republic of Korea
| | - Min Ho Lee
- b Forensic DNA Division , National Forensic Service , Wonju , Republic of Korea
| | - Do Hyun Kim
- a Department of Biomedical Laboratory Science, College of Health Sciences , Yonsei University , Wonju , Republic of Korea
| | - Ji Yeong Yang
- a Department of Biomedical Laboratory Science, College of Health Sciences , Yonsei University , Wonju , Republic of Korea
| | - Hyun Jun Woo
- a Department of Biomedical Laboratory Science, College of Health Sciences , Yonsei University , Wonju , Republic of Korea
| | - Hye Jin Kwon
- a Department of Biomedical Laboratory Science, College of Health Sciences , Yonsei University , Wonju , Republic of Korea
| | - Cheol Moon
- c Department of Clinical Laboratory Science , Semyung University , Jecheon , Republic of Korea
| | - Sa-Hyun Kim
- c Department of Clinical Laboratory Science , Semyung University , Jecheon , Republic of Korea
| | - Jong-Bae Kim
- a Department of Biomedical Laboratory Science, College of Health Sciences , Yonsei University , Wonju , Republic of Korea
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15
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Molina‐Santiago C. Insights in a novel gram‐positive type IV secretion system. Environ Microbiol 2018; 20:2334-2336. [DOI: 10.1111/1462-2920.14296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 05/24/2018] [Indexed: 11/29/2022]
Affiliation(s)
- Carlos Molina‐Santiago
- Departamento de MicrobiologíaInstituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga, Bulevar Louis Pasteur 31 (Campus Universitario de teatinos) Málaga Spain
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16
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Bagheri N, Salimzadeh L, Shirzad H. The role of T helper 1-cell response in Helicobacter pylori-infection. Microb Pathog 2018; 123:1-8. [PMID: 29936093 DOI: 10.1016/j.micpath.2018.06.033] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 06/19/2018] [Accepted: 06/21/2018] [Indexed: 12/11/2022]
Abstract
Helicobacter pylori (H. pylori) is a human pathogen affecting over 50% of the world population. This pathogen is usually associated with chronic inflammation of the gastric mucosa that can lead to peptic ulcer disease (PUD) and gastric cancer (GC), especially in susceptible individuals. These outcomes have been attributed to the interaction of several factors, including host genetic susceptibility, local innate and adaptive immune responses, virulence factors of H. pylori, and environmental factors. T helper (Th) cell subsets and their signature cytokines especially IFN-γ, contribute to anti-bacterial response, but at the mean time sustaining chronic inflammatory responses in the site of infection. It has been acknowledged that H. pylori-infection results in a Th1-dominant response and that inflammation of the gastric mucosa depends mainly on Th1 cell responses. But, the mechanism of the role of Th1 cell responses in H. pylori-infection has not yet been clearly explained. In this review, we will focus on the role of Th1 involved in H. pylori-infection, its interaction with Th17/Treg cells and its association with the clinical consequences of the infection.
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Affiliation(s)
- Nader Bagheri
- Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran.
| | - Loghman Salimzadeh
- Department of Microbiology and Immunology Programme, National University of Singapore, Singapore
| | - Hedayatollah Shirzad
- Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran.
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17
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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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18
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Beyond the Matrix: The Many Non-ECM Ligands for Integrins. Int J Mol Sci 2018; 19:ijms19020449. [PMID: 29393909 PMCID: PMC5855671 DOI: 10.3390/ijms19020449] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 01/21/2018] [Accepted: 01/30/2018] [Indexed: 12/17/2022] Open
Abstract
The traditional view of integrins portrays these highly conserved cell surface receptors as mediators of cellular attachment to the extracellular matrix (ECM), and to a lesser degree, as coordinators of leukocyte adhesion to the endothelium. These canonical activities are indispensable; however, there is also a wide variety of integrin functions mediated by non-ECM ligands that transcend the traditional roles of integrins. Some of these unorthodox roles involve cell-cell interactions and are engaged to support immune functions such as leukocyte transmigration, recognition of opsonization factors, and stimulation of neutrophil extracellular traps. Other cell-cell interactions mediated by integrins include hematopoietic stem cell and tumor cell homing to target tissues. Integrins also serve as cell-surface receptors for various growth factors, hormones, and small molecules. Interestingly, integrins have also been exploited by a wide variety of organisms including viruses and bacteria to support infectious activities such as cellular adhesion and/or cellular internalization. Additionally, the disruption of integrin function through the use of soluble integrin ligands is a common strategy adopted by several parasites in order to inhibit blood clotting during hematophagy, or by venomous snakes to kill prey. In this review, we strive to go beyond the matrix and summarize non-ECM ligands that interact with integrins in order to highlight these non-traditional functions of integrins.
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19
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NF-κB/miR-223-3p/ARID1A axis is involved in Helicobacter pylori CagA-induced gastric carcinogenesis and progression. Cell Death Dis 2018; 9:12. [PMID: 29317648 PMCID: PMC5849037 DOI: 10.1038/s41419-017-0020-9] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 09/30/2017] [Accepted: 10/02/2017] [Indexed: 12/29/2022]
Abstract
Infection with Helicobacter pylori (H. pylori) and the resulting gastric inflammation is regarded as the strongest risk factor for gastric carcinogenesis and progression. NF-κB plays an important role in linking H. pylori-mediated inflammation to cancer. However, the underlying mechanisms are poorly understood. In this study, we find that H. pylori infection induces miR-223-3p expression in H. pylori CagA-dependent manner. NF-κB stimulates miR-223-3p expression via directly binding to the promoter of miR-223-3p and is required for H. pylori CagA-mediated upregulation of miR-223-3p. miR-223-3p promotes the proliferation and migration of gastric cancer cells by directly targeting ARID1A and decreasing its expression. Furthermore, miR-223-3p/ARID1A axis is involved in CagA-induced cell proliferation and migration. In the clinical setting, the level of miR-223-3p is upregulated, while ARID1A is downregulated significantly in human gastric cancer tissues compared with the corresponding noncancerous tissues. The expression level of miR-223-3p is significantly higher in H. pylori-positive gastric cancer tissues than that in H. pylori-negative tissues. Moreover, a negative correlation between miR-223-3p and ARID1A expression is found in the gastric cancer tissues. Taken together, our findings suggested NF-κB/miR-223-3p/ARID1A axis may link the process of H. pylori-induced chronic inflammation to gastric cancer, thereby providing a new insight into the mechanism underlying H. pylori-associated gastric diseases.
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20
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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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21
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Abstract
Escherichia coli and other Gram-negative and -positive bacteria employ type IV secretion systems (T4SSs) to translocate DNA and protein substrates, generally by contact-dependent mechanisms, to other cells. The T4SSs functionally encompass two major subfamilies, the conjugation systems and the effector translocators. The conjugation systems are responsible for interbacterial transfer of antibiotic resistance genes, virulence determinants, and genes encoding other traits of potential benefit to the bacterial host. The effector translocators are used by many Gram-negative pathogens for delivery of potentially hundreds of virulence proteins termed effectors to eukaryotic cells during infection. In E. coli and other species of Enterobacteriaceae, T4SSs identified to date function exclusively in conjugative DNA transfer. In these species, the plasmid-encoded systems can be classified as the P, F, and I types. The P-type systems are the simplest in terms of subunit composition and architecture, and members of this subfamily share features in common with the paradigmatic Agrobacterium tumefaciens VirB/VirD4 T4SS. This review will summarize our current knowledge of the E. coli systems and the A. tumefaciens P-type system, with emphasis on the structural diversity of the T4SSs. Ancestral P-, F-, and I-type systems were adapted throughout evolution to yield the extant effector translocators, and information about well-characterized effector translocators also is included to further illustrate the adaptive and mosaic nature of these highly versatile machines.
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22
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McClain MS, Beckett AC, Cover TL. Helicobacter pylori Vacuolating Toxin and Gastric Cancer. Toxins (Basel) 2017; 9:toxins9100316. [PMID: 29023421 PMCID: PMC5666363 DOI: 10.3390/toxins9100316] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 10/03/2017] [Accepted: 10/05/2017] [Indexed: 12/13/2022] Open
Abstract
Helicobacter pylori VacA is a channel-forming toxin unrelated to other known bacterial toxins. Most H. pylori strains contain a vacA gene, but there is marked variation among strains in VacA toxin activity. This variation is attributable to strain-specific variations in VacA amino acid sequences, as well as variations in the levels of VacA transcription and secretion. In this review, we discuss epidemiologic studies showing an association between specific vacA allelic types and gastric cancer, as well as studies that have used animal models to investigate VacA activities relevant to gastric cancer. We also discuss the mechanisms by which VacA-induced cellular alterations may contribute to the pathogenesis of gastric cancer.
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Affiliation(s)
- Mark S McClain
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
| | - Amber C Beckett
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
| | - Timothy L Cover
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN 37212, USA.
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23
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Redzej A, Ukleja M, Connery S, Trokter M, Felisberto-Rodrigues C, Cryar A, Thalassinos K, Hayward RD, Orlova EV, Waksman G. Structure of a VirD4 coupling protein bound to a VirB type IV secretion machinery. EMBO J 2017; 36:3080-3095. [PMID: 28923826 PMCID: PMC5916273 DOI: 10.15252/embj.201796629] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 08/09/2017] [Accepted: 08/22/2017] [Indexed: 01/26/2023] Open
Abstract
Type IV secretion (T4S) systems are versatile bacterial secretion systems mediating transport of protein and/or DNA. T4S systems are generally composed of 11 VirB proteins and 1 VirD protein (VirD4). The VirB1‐11 proteins assemble to form a secretion machinery and a pilus while the VirD4 protein is responsible for substrate recruitment. The structure of VirD4 in isolation is known; however, its structure bound to the VirB1‐11 apparatus has not been determined. Here, we purify a T4S system with VirD4 bound, define the biochemical requirements for complex formation and describe the protein–protein interaction network in which VirD4 is involved. We also solve the structure of this complex by negative stain electron microscopy, demonstrating that two copies of VirD4 dimers locate on both sides of the apparatus, in between the VirB4 ATPases. Given the central role of VirD4 in type IV secretion, our study provides mechanistic insights on a process that mediates the dangerous spread of antibiotic resistance genes among bacterial populations.
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Affiliation(s)
- Adam Redzej
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, London, UK
| | - Marta Ukleja
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, London, UK
| | - Sarah Connery
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, London, UK
| | - Martina Trokter
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, London, UK
| | | | - Adam Cryar
- Division of Biosciences, Institute of Structural and Molecular Biology, University College of London, London, UK
| | - Konstantinos Thalassinos
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, London, UK.,Division of Biosciences, Institute of Structural and Molecular Biology, University College of London, London, UK
| | - Richard D Hayward
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, London, UK.,Division of Biosciences, Institute of Structural and Molecular Biology, University College of London, London, UK
| | - Elena V Orlova
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, London, UK
| | - Gabriel Waksman
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, London, UK .,Division of Biosciences, Institute of Structural and Molecular Biology, University College of London, London, UK
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24
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Naz A, Obaid A, Awan FM, Ikram A, Ahmad J, Ali A. Petri Net-Based Model of Helicobacter pylori Mediated Disruption of Tight Junction Proteins in Stomach Lining during Gastric Carcinoma. Front Microbiol 2017; 8:1682. [PMID: 28932213 PMCID: PMC5592237 DOI: 10.3389/fmicb.2017.01682] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 08/21/2017] [Indexed: 12/13/2022] Open
Abstract
Tight junctions help prevent the passage of digestive enzymes and microorganisms through the space between adjacent epithelial cells lining. However, Helicobacter pylori encoded virulence factors negatively regulate these tight junctions and contribute to dysfunction of gastric mucosa. Here, we have predicted the regulation of important tight junction proteins, such as Zonula occludens-1, Claudin-2 and Connexin32 in the presence of pathogenic proteins. Molecular events such as post translational modifications and crosstalk between phosphorylation, O-glycosylation, palmitoylation and methylation are explored which may compromise the integrity of these tight junction proteins. Furthermore, the signaling pathways disrupted by dysregulated kinases, proteins and post-translational modifications are reviewed to design an abstracted computational model showing the situation-dependent dynamic behaviors of these biological processes and entities. A qualitative hybrid Petri Net model is therefore constructed showing the altered host pathways in the presence of virulence factor cytotoxin-associated gene A, leading to the disruption of tight junction proteins. The model is qualitative logic-based, which does not depend on any kinetic parameter and quantitative data and depends on knowledge derived from experiments. The designed model provides insights into the tight junction disruption and disease progression. Model is then verified by the available experimental data, nevertheless formal in vitro experimentation is a promising way to ensure its validation. The major findings propose that H. pylori activated kinases are responsible to trigger specific post translational modifications within tight junction proteins, at specific sites. These modifications may favor alterations in gastric barrier and provide a route to bacterial invasion into host cells.
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Affiliation(s)
- Anam Naz
- Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and TechnologyIslamabad, Pakistan
| | - Ayesha Obaid
- Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and TechnologyIslamabad, Pakistan
| | - Faryal M. Awan
- Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and TechnologyIslamabad, Pakistan
| | - Aqsa Ikram
- Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and TechnologyIslamabad, Pakistan
| | - Jamil Ahmad
- Research Center for Modeling & Simulation, National University of Sciences and TechnologyIslamabad, Pakistan
| | - Amjad Ali
- Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and TechnologyIslamabad, Pakistan
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25
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The Middle Fragment of Helicobacter pylori CagA Induces Actin Rearrangement and Triggers Its Own Uptake into Gastric Epithelial Cells. Toxins (Basel) 2017; 9:toxins9080237. [PMID: 28788072 PMCID: PMC5577571 DOI: 10.3390/toxins9080237] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 07/07/2017] [Accepted: 07/26/2017] [Indexed: 01/14/2023] Open
Abstract
Cytotoxin-associated gene product A (CagA) is a major virulence factor secreted by Helicobacter pylori. CagA activity in the gastric epithelium is associated with higher risk of gastric cancer development. Bacterial type IV secretion system (T4SS)-mediated translocation of CagA into the cytosol of human epithelial cells occurs via a poorly understood mechanism that requires CagA interaction with the host membrane lipid phosphatidylserine (PS) and host cell receptor integrin α5β1. Here we have characterized the isolated recombinant middle fragment of CagA (CagA-M) that contains the positively-charged PS-binding region (aa 613–636) and a putative β1 integrin binding site, but lacks the EPIYA region, secretion signal peptide and the CagA multimerization motif. We show that CagA-M, when immobilized on latex beads, is capable of binding to, and triggering its own uptake into, gastric epithelial cells in the absence of infection with cagA-positive H. pylori. Using site-directed mutagenesis, fluorescent and electron microscopy, and highly-specific inhibitors, we demonstrate that the cell-binding and endocytosis-like internalization of CagA-M are dependent on (1) binding to PS; (2) β1 integrin activity; and (3) actin dynamics. Interaction of CagA-M with the host cells is accompanied by the development of long filopodia-like protrusions (macrospikes). This novel morphology is different from the hummingbird phenotype induced by the translocation of full-length CagA. The determinants within CagA-M and within the host that are important for endocytosis-like internalization into host cells are very similar to those observed for T4SS-mediated internalization of full-length CagA, suggesting that the latter may involve an endocytic pathway.
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26
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Helicobacter pylori modulates host cell responses by CagT4SS-dependent translocation of an intermediate metabolite of LPS inner core heptose biosynthesis. PLoS Pathog 2017; 13:e1006514. [PMID: 28715499 PMCID: PMC5531669 DOI: 10.1371/journal.ppat.1006514] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 07/27/2017] [Accepted: 07/05/2017] [Indexed: 12/15/2022] Open
Abstract
Highly virulent Helicobacter pylori cause proinflammatory signaling inducing the transcriptional activation and secretion of cytokines such as IL-8 in epithelial cells. Responsible in part for this signaling is the cag pathogenicity island (cagPAI) that codetermines the risk for pathological sequelae of an H. pylori infection such as gastric cancer. The Cag type IV secretion system (CagT4SS), encoded on the cagPAI, can translocate various molecules into cells, the effector protein CagA, peptidoglycan metabolites and DNA. Although these transported molecules are known to contribute to cellular responses to some extent, a major part of the cagPAI-induced signaling leading to IL-8 secretion remains unexplained. We report here that biosynthesis of heptose-1,7-bisphosphate (HBP), an important intermediate metabolite of LPS inner heptose core, contributes in a major way to the H. pylori cagPAI-dependent induction of proinflammatory signaling and IL-8 secretion in human epithelial cells. Mutants defective in the genes required for synthesis of HBP exhibited a more than 95% reduction of IL-8 induction and impaired CagT4SS-dependent cellular signaling. The loss of HBP biosynthesis did not abolish the ability to translocate CagA. The human cellular adaptor TIFA, which was described before to mediate HBP-dependent activity in other Gram-negative bacteria, was crucial in the cagPAI- and HBP pathway-induced responses by H. pylori in different cell types. The active metabolite was present in H. pylori lysates but not enriched in bacterial supernatants. These novel results advance our mechanistic understanding of H. pylori cagPAI-dependent signaling mediated by intracellular pattern recognition receptors. They will also allow to better dissect immunomodulatory activities by H. pylori and to improve the possibilities of intervention in cagPAI- and inflammation-driven cancerogenesis. The Cag Type IV secretion system, which contributes to inflammation and cancerogenesis during chronic infection, is one of the major virulence and fitness factors of the bacterial gastric pathogen Helicobacter pylori. Up to now, the mechanisms leading to cagPAI-dependent signal transduction and cytokine secretion were not completely understood. We report here that HBP, an intermediate metabolite in LPS core heptose biosynthesis, is translocated into host cells dependent on the CagT4SS, and is a major factor leading to the activation of cellular responses. This response is connected to the human cellular adaptor protein TIFA. The knowledge of this specific response pathway is a major advance in understanding CagT4SS-dependent signaling and will enable us to understand better how H. pylori modulates the immune response repertoire in its human host.
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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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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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Merino E, Flores-Encarnación M, Aguilar-Gutiérrez GR. Functional interaction and structural characteristics of unique components of Helicobacter pylori T4SS. FEBS J 2017; 284:3540-3549. [PMID: 28470874 DOI: 10.1111/febs.14092] [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: 11/07/2016] [Revised: 03/14/2017] [Accepted: 04/26/2017] [Indexed: 12/25/2022]
Abstract
The Helicobacter pylori infection of the human gastric mucosa causes chronic active gastritis and peptic ulcers and is associated with the development of gastric cancer. Epidemiological studies show that these gastric diseases are related to virulent H. pylori strains that harbor the cytotoxin-associated gene pathogenicity island (cag PAI). The cag PAI is a DNA insertion in the H. pylori chromosome that encodes ~ 27 proteins, including the oncoprotein CagA. Approximately 20 of these proteins have been designated as cag type IV secretion system (T4SS) components. However, only 11 of these proteins share function, structure, and/or sequence similarities with the prototypical VirB/VirD4 T4SS of Agrobacterium tumefaciens. The VirB/VirD4 orthologs of the cag T4SS of H. pylori are required for CagA translocation and stimulate the gastric epithelial cells to produce and secrete interleukin-8 (IL-8). The cag PAI encodes eight additional proteins, such as Cag3 (Cagδ/HP0522), CagM (Cag16/HP0537), CagU (Cag11/HP0531), CagI (Cag19/HP0540), and CagH (Cag20/HP0541), which are also required for the translocation of CagA and IL-8 secretion, meanwhile CagF (Cag22/HP0543), CagG (Cag21/HP0542), and CagZ (Cag6/HP0526) are just required for the translocation of CagA. However, relatively little is known about their functions and structural organization because they exhibit a nondetectable sequence similarity with T4SS components in the current databases. In this review, we conducted an exhaustive analysis of the literature to present the biochemistry, putative role, localization, and interactions of each of these eight additional cag T4SS components.
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Affiliation(s)
- Enrique Merino
- Enrique Merino, Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Marcos Flores-Encarnación
- Marcos Flores-Encarnación, Laboratorio de Microbiología Molecular y Celular, Facultad de Medicina, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | - Germán Rubén Aguilar-Gutiérrez
- Germán Rubén Aguilar-Gutiérrez, Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, México
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Matsuo Y, Kido Y, Yamaoka Y. Helicobacter pylori Outer Membrane Protein-Related Pathogenesis. Toxins (Basel) 2017; 9:toxins9030101. [PMID: 28287480 PMCID: PMC5371856 DOI: 10.3390/toxins9030101] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 12/16/2022] Open
Abstract
Helicobacter pylori colonizes the human stomach and induces inflammation, and in some cases persistent infection can result in gastric cancer. Attachment to the gastric mucosa is the first step in establishing bacterial colonization, and outer membrane proteins (OMPs) play a pivotal role in binding to human cells. Some OMP interaction molecules are known in H. pylori, and their associated host cell responses have been gradually clarified. Many studies have demonstrated that OMPs are essential to CagA translocation into gastric cells via the Type IV secretion system of H. pylori. This review summarizes the mechanisms through which H. pylori utilizes OMPs to colonize the human stomach and how OMPs cooperate with the Type IV secretion system.
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Affiliation(s)
- Yuichi Matsuo
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, 1-1 Idaigaoka, Hasama-Machi, Yufu-City, Oita 879-5593, Japan.
| | - Yasutoshi Kido
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, 1-1 Idaigaoka, Hasama-Machi, Yufu-City, Oita 879-5593, Japan.
| | - Yoshio Yamaoka
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, 1-1 Idaigaoka, Hasama-Machi, Yufu-City, Oita 879-5593, Japan.
- Department of Medicine-Gastroenterology, Michael E. DeBakey Veterans Affairs Medical Center and Baylor College of Medicine, Houston, TX 77030, USA.
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Zhang J, Fan F, Zhao Y, Sun L, Liu Y, Keegan RM, Isupov MN, Wu Y. Crystal structure of the type IV secretion system component CagX from Helicobacter pylori. Acta Crystallogr F Struct Biol Commun 2017; 73:167-173. [PMID: 28291753 PMCID: PMC5349311 DOI: 10.1107/s2053230x17001376] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 01/26/2017] [Indexed: 12/28/2022] Open
Abstract
Helicobacter pylori, a Gram-negative bacterial pathogen prevalent in the human population, is the causative agent of severe gastric diseases. An H. pylori type IV secretion (T4S) system encoded by the cytotoxin-associated gene pathogenicity island (cagPAI) is responsible for communication with host cells. As a component of the cagPAI T4S system core complex, CagX plays an important role in virulence-protein translocation into the host cells. In this work, the crystal structure of the C-terminal domain of CagX (CagXct), which is a homologue of the VirB9 protein from the VirB/D4 T4S system, is presented. CagXct is only the second three-dimensional structure to be elucidated of a VirB9-like protein. Another homologue, TraO, which is encoded on the Escherichia coli conjugative plasmid pKM101, shares only 19% sequence identity with CagXct; however, there is a remarkable similarity in tertiary structure between these two β-sandwich protein domains. Most of the residues that are conserved between CagXct and TraO are located within the protein core and appear to be responsible for the preservation of this domain fold. The studies presented here will contribute to our understanding of different bacterial T4S systems.
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Affiliation(s)
- Jin Zhang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, Fuzhou 350002, People’s Republic of China
| | - Fei Fan
- Fujian Health College, Fuzhou 350101, People’s Republic of China
| | - Yanhe Zhao
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, Fuzhou 350002, People’s Republic of China
| | - Lifang Sun
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, Fuzhou 350002, People’s Republic of China
| | - Yadan Liu
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, Fuzhou 350002, People’s Republic of China
| | - Ronan M. Keegan
- CCP4, Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0FA, England
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, England
| | - Michail N. Isupov
- The Henry Wellcome Building for Biocatalysis, Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, England
| | - Yunkun Wu
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, Fuzhou 350002, People’s Republic of China
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The Helicobacter pylori Autotransporter ImaA Tempers the Bacterium's Interaction with α5β1 Integrin. Infect Immun 2016; 85:IAI.00450-16. [PMID: 27795352 DOI: 10.1128/iai.00450-16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 10/07/2016] [Indexed: 02/07/2023] Open
Abstract
The human pathogen Helicobacter pylori uses the host receptor α5β1 integrin to trigger inflammation in host cells via its cag pathogenicity island (cag PAI) type IV secretion system (T4SS). Here, we report that the H. pylori ImaA protein (HP0289) decreases the action of the cag PAI T4SS via tempering the bacterium's interaction with α5β1 integrin. Previously, imaA-null mutants were found to induce an elevated inflammatory response that was dependent on the cag PAI T4SS; here we extend those findings to show that the elevated response is independent of the CagA effector protein. To understand how ImaA could be affecting cag PAI T4SS activity at the host cell interface, we utilized the Phyre structural threading program and found that ImaA has a region with remote homology to bacterial integrin-binding proteins. This region was required for ImaA function. Unexpectedly, we observed that imaA mutants bound higher levels of α5β1 integrin than wild-type H. pylori, an outcome that required the predicted integrin-binding homology region of ImaA. Lastly, we report that ImaA directly affected the amount of host cell β1 integrin but not other cellular integrins. Our results thus suggest a model in which H. pylori employs ImaA to regulate interactions between integrin and the T4SS and thus alter the host inflammatory strength.
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Systematic site-directed mutagenesis of the Helicobacter pylori CagL protein of the Cag type IV secretion system identifies novel functional domains. Sci Rep 2016; 6:38101. [PMID: 27922023 PMCID: PMC5138618 DOI: 10.1038/srep38101] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 11/04/2016] [Indexed: 12/19/2022] Open
Abstract
The Cag Type IV secretion system, which contributes to inflammation and cancerogenesis during chronic infection, is one of the major virulence factors of the bacterial gastric pathogen Helicobacter pylori. We have generated and characterized a series of non-marked site-directed chromosomal mutants in H. pylori to define domains of unknown function of the essential tip protein CagL of the Cag secretion system. Characterizing the CagL mutants, we determined that their function to activate cells and transport the effector CagA was reduced to different extents. We identified three novel regions of the CagL protein, involved in its structural integrity, its possible interaction with the CagPAI T4SS pilus protein CagI, and in its binding to integrins and other host cell ligands. In particular two novel variable CagL motifs were involved in integrin binding, TSPSA, and TASLI, which is located opposite of its integrin binding motif RGD. We thereby defined
functionally important subdomains within the CagL structure, which can be used to clarify CagL contributions in the context of other CagPAI proteins or for inhibition of the CagT4SS. This structure-function correlation of CagL domains can also be instructive for the functional characterization of other potential VirB5 orthologs whose structure is not yet known.
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Wang G, Romero-Gallo J, Benoit SL, Piazuelo MB, Dominguez RL, Morgan DR, Peek RM, Maier RJ. Hydrogen Metabolism in Helicobacter pylori Plays a Role in Gastric Carcinogenesis through Facilitating CagA Translocation. mBio 2016; 7:e01022-16. [PMID: 27531909 PMCID: PMC4992972 DOI: 10.1128/mbio.01022-16] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 07/15/2016] [Indexed: 02/06/2023] Open
Abstract
UNLABELLED A known virulence factor of Helicobacter pylori that augments gastric cancer risk is the CagA cytotoxin. A carcinogenic derivative strain, 7.13, that has a greater ability to translocate CagA exhibits much higher hydrogenase activity than its parent noncarcinogenic strain, B128. A Δhyd mutant strain with deletion of hydrogenase genes was ineffective in CagA translocation into human gastric epithelial AGS cells, while no significant attenuation of cell adhesion was observed. The quinone reductase inhibitor 2-n-heptyl-4-hydroxyquinoline-N-oxide (HQNO) was used to specifically inhibit the H2-utilizing respiratory chain of outer membrane-permeabilized bacterial cells; that level of inhibitor also greatly attenuated CagA translocation into AGS cells, indicating the H2-generated transmembrane potential is a contributor to toxin translocation. The Δhyd strain showed a decreased frequency of DNA transformation, suggesting that H. pylori hydrogenase is also involved in energizing the DNA uptake apparatus. In a gerbil model of infection, the ability of the Δhyd strain to induce inflammation was significantly attenuated (at 12 weeks postinoculation), while all of the gerbils infected with the parent strain (7.13) exhibited a high level of inflammation. Gastric cancer developed in 50% of gerbils infected with the wild-type strain 7.13 but in none of the animals infected with the Δhyd strain. By examining the hydrogenase activities from well-defined clinical H. pylori isolates, we observed that strains isolated from cancer patients (n = 6) have a significantly higher hydrogenase (H2/O2) activity than the strains isolated from gastritis patients (n = 6), further supporting an association between H. pylori hydrogenase activity and gastric carcinogenesis in humans. IMPORTANCE Hydrogen-utilizing hydrogenases are known to be important for some respiratory pathogens to colonize hosts. Here a gastric cancer connection is made via a pathogen's (H. pylori) use of molecular hydrogen, a host microbiome-produced gas. Delivery of the known carcinogenic factor CagA into host cells is augmented by the H2-utilizing respiratory chain of the bacterium. The role of hydrogenase in carcinogenesis is demonstrated in an animal model, whereby inflammation markers and cancer development were attenuated in the hydrogenase-null strain. Hydrogenase activity comparisons of clinical strains of the pathogen also support a connection between hydrogen metabolism and gastric cancer risk. While molecular hydrogen use is acknowledged to be an alternative high-energy substrate for some pathogens, this work extends the roles of H2 oxidation to include transport of a carcinogenic toxin. The work provides a new avenue for exploratory treatment of some cancers via microflora alterations.
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Affiliation(s)
- Ge Wang
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Judith Romero-Gallo
- Division of Gastroenterology, Department of Medicine, Hepatology and Nutrition, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Stéphane L Benoit
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - M Blanca Piazuelo
- Division of Gastroenterology, Department of Medicine, Hepatology and Nutrition, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | | | - Douglas R Morgan
- Division of Gastroenterology, Department of Medicine, Hepatology and Nutrition, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Richard M Peek
- Division of Gastroenterology, Department of Medicine, Hepatology and Nutrition, Vanderbilt University School of Medicine, Nashville, Tennessee, USA Departments of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Robert J Maier
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
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The role of NLRP3 and AIM2 in inflammasome activation during Brucella abortus infection. Semin Immunopathol 2016; 39:215-223. [PMID: 27405866 DOI: 10.1007/s00281-016-0581-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 07/04/2016] [Indexed: 01/18/2023]
Abstract
The innate immune system is essential for the detection and elimination of bacterial pathogens. Upon inflammasome activation, caspase-1 cleaves pro-IL-1β and pro-IL-18 to their mature forms IL-1β and IL-18, respectively, and the cell undergoes inflammatory death termed pyroptosis. Here, we reviewed recent findings demonstrating that Brucella abortus ligands activate NLRP3 and AIM2 inflammasomes which lead to control of infection. This protective effect is due to the inflammatory response caused by IL-1β and IL-18 rather than cell death. Brucella DNA is sensed by AIM2 and bacteria-induced mitochondrial reactive oxygen species is detected by NLRP3. However, deregulation of pro-inflammatory cytokine production can lead to immunopathology. Nervous system invasion by bacteria of the genus Brucella results in an inflammatory disorder termed neurobrucellosis. Herein, we discuss the mechanism of caspase-1 activation and IL-1β secretion in glial cells infected with B. abortus. Our results demonstrate that the ASC inflammasome is indispensable for inducing the activation of caspase-1 and secretion of IL-1β upon infection of astrocytes and microglia with Brucella. Moreover, our results demonstrate that secretion of IL-1β by Brucella-infected glial cells depends on NLRP3 and AIM2 and leads to neurobrucellosis. Further, the inhibition of the host cell inflammasome as an immune evasion strategy has been described for bacterial pathogens. We discuss here that the bacterial type IV secretion system VirB is required for inflammasome activation in host cells during infection. Taken together, our results indicate that Brucella is sensed by ASC inflammasomes mainly NLRP3 and AIM2 that collectively orchestrate a robust caspase-1 activation and pro-inflammatory response.
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Gillespie JJ, Phan IQH, Driscoll TP, Guillotte ML, Lehman SS, Rennoll-Bankert KE, Subramanian S, Beier-Sexton M, Myler PJ, Rahman MS, Azad AF. The Rickettsia type IV secretion system: unrealized complexity mired by gene family expansion. Pathog Dis 2016; 74:ftw058. [PMID: 27307105 PMCID: PMC5505475 DOI: 10.1093/femspd/ftw058] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/03/2016] [Indexed: 12/22/2022] Open
Abstract
Many prokaryotes utilize type IV secretion systems (T4SSs) to translocate substrates (e.g. nucleoprotein, DNA, protein) across the cell envelope, and/or to elaborate surface structures (i.e. pili or adhesins). Among eight distinct T4SS classes, P-T4SSs are typified by the Agrobacterium tumefaciens vir T4SS, which is comprised of 12 scaffold components (VirB1-VirB11, VirD4). While most P-T4SSs include all 12 Vir proteins, some differ from the vir archetype by either containing additional scaffold components not analogous to Vir proteins or lacking one or more of the Vir proteins. In a special case, the Rickettsiales vir homolog (rvh) P-T4SS comprises unprecedented gene family expansion. rvh contains three families of gene duplications (rvhB9, rvhB8, rvhB4): RvhB9,8,4-I are conserved relative to equivalents in other P-T4SSs, while RvhB9,8,4-II have evolved atypical features that deviate substantially from other homologs. Furthermore, rvh contains five VirB6-like genes (rvhB6a-e), which are tandemly arrayed and contain large N- and C-terminal extensions. Our work herein focuses on the complexity underpinned by rvh gene family expansion. Furthermore, we describe an RvhB10 insertion, which occurs in a region that forms the T4SS pore. The significance of these curious properties to rvh structure and function is evaluated, shedding light on a highly complex T4SS.
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Affiliation(s)
- Joseph J Gillespie
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W. Baltimore St., HSF I Suite 380, Baltimore, MD 21201, USA
| | - Isabelle Q H Phan
- Seattle Structural Genomics Center for Infectious Disease, 307 Westlake Ave North, Seattle, WA 98109, USA Center for Infectious Disease Research (formerly Seattle Biomedical Research Institute), Seattle, WA 98109, USA
| | - Timothy P Driscoll
- Department of Biology, West Virginia University, Life Sciences Building, PO Box 6057, Morgantown, WV 26506-6201, USA
| | - Mark L Guillotte
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W. Baltimore St., HSF I Suite 380, Baltimore, MD 21201, USA
| | - Stephanie S Lehman
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W. Baltimore St., HSF I Suite 380, Baltimore, MD 21201, USA
| | - Kristen E Rennoll-Bankert
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W. Baltimore St., HSF I Suite 380, Baltimore, MD 21201, USA
| | - Sandhya Subramanian
- Seattle Structural Genomics Center for Infectious Disease, 307 Westlake Ave North, Seattle, WA 98109, USA Center for Infectious Disease Research (formerly Seattle Biomedical Research Institute), Seattle, WA 98109, USA
| | - Magda Beier-Sexton
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W. Baltimore St., HSF I Suite 380, Baltimore, MD 21201, USA
| | - Peter J Myler
- Seattle Structural Genomics Center for Infectious Disease, 307 Westlake Ave North, Seattle, WA 98109, USA Center for Infectious Disease Research (formerly Seattle Biomedical Research Institute), Seattle, WA 98109, USA
| | - M Sayeedur Rahman
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W. Baltimore St., HSF I Suite 380, Baltimore, MD 21201, USA
| | - Abdu F Azad
- Department of Microbiology and Immunology, University of Maryland School of Medicine, 685 W. Baltimore St., HSF I Suite 380, Baltimore, MD 21201, USA
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Wang X, Ling F, Wang H, Yu M, Zhu H, Chen C, Qian J, Liu C, Zhang Y, Shao S. The Helicobacter pylori Cag Pathogenicity Island Protein Cag1 is Associated with the Function of T4SS. Curr Microbiol 2016; 73:22-30. [PMID: 26971262 DOI: 10.1007/s00284-016-1016-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 01/20/2016] [Indexed: 12/29/2022]
Abstract
The human pathogen Helicobacter pylori is involved in gastric diseases ranging from gastritis to gastric cancer. Virulent strains harboring the cag pathogenicity island (cag PAI) which encode a Type IV Secretion System (T4SS) can induce pro-inflammatory cytokines such as interleukin-8 and deliver their major effector proteins CagA into the gastric cells. While a subset of cag PAI genes have been identified to be the homologues of T4SS genes from Agrobacterium tumefaciens, a majority have unknown functions. We have identified one of such proteins, Cag1, which was predicted to be a non-classically secreted and virulent protein. Our results showed that Cag1 is a membrane-associated protein essential for the induction of multiple cytokine secretions, and cag1-deficient mutant has partial influence on CagA translocation; while the protein itself was not injected into host cells. Our data indicated that Cag1 is located in the bacterial membrane and is associated with the function of T4SS.
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Affiliation(s)
- Xiaochun Wang
- Department of Pathogenic Biology, School of Medical Science, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Feng Ling
- Department of Clinical Laboratory, Kunshan Hospital of Traditional Chinese Medicine, Kunshan, 215300, Jiangsu, China
| | - Hua Wang
- Department of Pathogenic Biology, School of Medical Science, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Min Yu
- Department of Pathogenic Biology, School of Medical Science, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Hong Zhu
- Department of Pathogenic Biology, School of Medical Science, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Cheng Chen
- Department of Pathogenic Biology, School of Medical Science, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Jingyi Qian
- Department of Pathogenic Biology, School of Medical Science, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Chang Liu
- Department of Pathogenic Biology, School of Medical Science, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Yuanyuan Zhang
- Department of Pathogenic Biology, School of Medical Science, Jiangsu University, Zhenjiang, 212013, Jiangsu, China
| | - Shihe Shao
- Department of Pathogenic Biology, School of Medical Science, Jiangsu University, Zhenjiang, 212013, Jiangsu, China.
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Pérez-Figueroa E, Torres J, Sánchez-Zauco N, Contreras-Ramos A, Alvarez-Arellano L, Maldonado-Bernal C. Activation of NLRP3 inflammasome in human neutrophils by Helicobacter pylori infection. Innate Immun 2016; 22:103-112. [DOI: 10.1177/1753425915619475] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
Abstract
TLRs and NLRs participate in the immune system recognition of Helicobacter pylori. However, little is known about the mechanisms leading to inflammasome activation by H. pylori and if NLRs in neutrophils are involved in the process. We studied how NOD-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome components are involved in IL-1β maturation in human neutrophils in response to the infection and if they are dependent on T4SS (type IV secretion system) and TLRs. Human neutrophils were cultured and infected with the 26695 or the VirD4− H. pylori strains; the IL-1β concentration was analyzed by ELISA, and we also evaluated the activation of TLRs 2 and 4. The infection of neutrophils with both strains of H. pylori induced production of IL-1β and expression of the NLRP3 inflammasome components such as apoptosis-associated speck-like protein with CARD domain and NLRP3 protein. The infection also increased the activity of caspase-1, which is required for the maturation of IL-1β. Our study shows, for the first time, that H. pylori infection induces the expression and activation of components of NLRP3 inflammasomes in human neutrophils and that the activation is independent of a functional T4SS and TLR2 and TLR4.
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Affiliation(s)
- Erandi Pérez-Figueroa
- Laboratorio de Investigación en Inmunología y Proteómica, Hospital Infantil de México Federico Gómez, México City, México
- Unidad de Investigación Médica en Enfermedades Infecciosas, Hospital de Pediatría, CMN SXXI, IMSS, México City, México
| | - Javier Torres
- Unidad de Investigación Médica en Enfermedades Infecciosas, Hospital de Pediatría, CMN SXXI, IMSS, México City, México
| | - Norma Sánchez-Zauco
- Laboratorio de Investigación en Inmunología y Proteómica, Hospital Infantil de México Federico Gómez, México City, México
- Unidad de Investigación Médica en Enfermedades Infecciosas, Hospital de Pediatría, CMN SXXI, IMSS, México City, México
| | - Alejandra Contreras-Ramos
- Laboratorio de Biología del Desarrollo, Hospital Infantil de México Federico Gómez, México City, México
| | | | - Carmen Maldonado-Bernal
- Laboratorio de Investigación en Inmunología y Proteómica, Hospital Infantil de México Federico Gómez, México City, México
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Structural Interactions of Curcumin Biotransformed Molecules with the N-Terminal Residues of Cytotoxic-Associated Gene A Protein Provide Insights into Suppression of Oncogenic Activities. Interdiscip Sci 2016; 9:116-129. [PMID: 26798036 DOI: 10.1007/s12539-016-0142-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 12/21/2015] [Accepted: 01/04/2016] [Indexed: 01/01/2023]
Abstract
Curcumin as a natural product has drawn considerable attention in recent years for its multiple pharmacological activities against various diseases, but more studies are required to understand the curcumin pharmacological action considering its low bioavailability. Though numerous reasons contribute to the low bioavailability of curcumin, one of the important reasons is associated with biotransformation of curcumin through either conjugation or reduction depending on curcumin administration route. The orally administered curcumin (CUR) is metabolised into curcumin glucuronidase (CUR-GLR) and curcumin sulphate by conjugation, whereas dihydroxycurcumin, tetrahydrocurcumin, and hexahydrocurcumin (HHC) are formed by reduction after intraperitoneal administration of curcumin. The main aim of the current study was to investigate the pharmacological properties of curcumin and its biotransformed molecules and its inhibitory potential against CagA (cytotoxic-associated gene A) oncoprotein of Helicobacter pylori. All lead molecules followed the Lipinski's five rules for biological activities, except CUR-GLR, whereas druglikeness scores were obtained for all molecules. Subsequently, molecular docking was employed to analyse the binding affinity of molecules with CagA. The docking studies revealed that CUR-GLR has highest binding affinity with CagA, whereas less interactive affinity was observed in HHC. From the virtual screening and docking studies, the current study suggests that the biotransformation of curcumin through conjugation has more potential for inhibition of oncogenic activities of CagA+ H. pylori than reduction.
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Molecular and Structural Analysis of the Helicobacter pylori cag Type IV Secretion System Core Complex. mBio 2016; 7:e02001-15. [PMID: 26758182 PMCID: PMC4725015 DOI: 10.1128/mbio.02001-15] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Bacterial type IV secretion systems (T4SSs) can function to export or import DNA, and can deliver effector proteins into a wide range of target cells. Relatively little is known about the structural organization of T4SSs that secrete effector proteins. In this report, we describe the isolation and analysis of a membrane-spanning core complex from the Helicobacter pylori cag T4SS, which has an important role in the pathogenesis of gastric cancer. We show that this complex contains five H. pylori proteins, CagM, CagT, Cag3, CagX, and CagY, each of which is required for cag T4SS activity. CagX and CagY are orthologous to the VirB9 and VirB10 components of T4SSs in other bacterial species, and the other three Cag proteins are unique to H. pylori. Negative stain single-particle electron microscopy revealed complexes 41 nm in diameter, characterized by a 19-nm-diameter central ring linked to an outer ring by spoke-like linkers. Incomplete complexes formed by Δcag3 or ΔcagT mutants retain the 19-nm-diameter ring but lack an organized outer ring. Immunogold labeling studies confirm that Cag3 is a peripheral component of the complex. The cag T4SS core complex has an overall diameter and structural organization that differ considerably from the corresponding features of conjugative T4SSs. These results highlight specialized features of the H. pylori cag T4SS that are optimized for function in the human gastric mucosal environment. Type IV secretion systems (T4SSs) are versatile macromolecular machines that are present in many bacterial species. In this study, we investigated a T4SS found in the bacterium Helicobacter pylori. H. pylori is an important cause of stomach cancer, and the H. pylori T4SS contributes to cancer pathogenesis by mediating entry of CagA (an effector protein regarded as a “bacterial oncoprotein”) into gastric epithelial cells. We isolated and analyzed the membrane-spanning core complex of the H. pylori T4SS and showed that it contains unique proteins unrelated to components of T4SSs in other bacterial species. These results constitute the first structural analysis of the core complex from this important secretion system.
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Frank J, Dingemanse C, Schmitz AM, Vossen RHAM, van Ommen GJB, den Dunnen JT, Robanus-Maandag EC, Anvar SY. The Complete Genome Sequence of the Murine Pathobiont Helicobacter typhlonius. Front Microbiol 2016; 6:1549. [PMID: 26779178 PMCID: PMC4705304 DOI: 10.3389/fmicb.2015.01549] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 12/21/2015] [Indexed: 01/27/2023] Open
Abstract
Background: Immuno-compromised mice infected with Helicobacter typhlonius are used to model microbially inducted inflammatory bowel disease (IBD). The specific mechanism through which H. typhlonius induces and promotes IBD is not fully understood. Access to the genome sequence is essential to examine emergent properties of this organism, such as its pathogenicity. To this end, we present the complete genome sequence of H. typhlonius MIT 97-6810, obtained through single-molecule real-time sequencing. Results: The genome was assembled into a single circularized contig measuring 1.92 Mbp with an average GC content of 38.8%. In total 2,117 protein-encoding genes and 43 RNA genes were identified. Numerous pathogenic features were found, including a putative pathogenicity island (PAIs) containing components of type IV secretion system, virulence-associated proteins and cag PAI protein. We compared the genome of H. typhlonius to those of the murine pathobiont H. hepaticus and human pathobiont H. pylori. H. typhlonius resembles H. hepaticus most with 1,594 (75.3%) of its genes being orthologous to genes in H. hepaticus. Determination of the global methylation state revealed eight distinct recognition motifs for adenine and cytosine methylation. H. typhlonius shares four of its recognition motifs with H. pylori. Conclusion: The complete genome sequence of H. typhlonius MIT 97-6810 enabled us to identify many pathogenic features suggesting that H. typhlonius can act as a pathogen. Follow-up studies are necessary to evaluate the true nature of its pathogenic capabilities. We found many methylated sites and a plethora of restriction-modification systems. The genome, together with the methylome, will provide an essential resource for future studies investigating gene regulation, host interaction and pathogenicity of H. typhlonius. In turn, this work can contribute to unraveling the role of Helicobacter in enteric disease.
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Affiliation(s)
- Jeroen Frank
- Leiden Genome Technology Center, Leiden University Medical Center Leiden, Netherlands
| | - Celia Dingemanse
- Department of Human Genetics, Leiden University Medical Center Leiden, Netherlands
| | - Arnoud M Schmitz
- Leiden Genome Technology Center, Leiden University Medical Center Leiden, Netherlands
| | - Rolf H A M Vossen
- Leiden Genome Technology Center, Leiden University Medical Center Leiden, Netherlands
| | - Gert-Jan B van Ommen
- Department of Human Genetics, Leiden University Medical Center Leiden, Netherlands
| | - Johan T den Dunnen
- Leiden Genome Technology Center, Leiden University Medical CenterLeiden, Netherlands; Department of Human Genetics, Leiden University Medical CenterLeiden, Netherlands; Department of Clinical Genetics, Leiden University Medical CenterLeiden, Netherlands
| | | | - Seyed Yahya Anvar
- Leiden Genome Technology Center, Leiden University Medical CenterLeiden, Netherlands; Department of Human Genetics, Leiden University Medical CenterLeiden, Netherlands
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Abstract
Type IV secretion systems (T4SSs) are large multisubunit translocons, found in both gram-negative and gram-positive bacteria and in some archaea. These systems transport a diverse array of substrates from DNA and protein-DNA complexes to proteins, and play fundamental roles in both bacterial pathogenesis and bacterial adaptation to the cellular milieu in which bacteria live. This review describes the various biochemical and structural advances made toward understanding the biogenesis, architecture, and function of T4SSs.
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Affiliation(s)
- Vidya Chandran Darbari
- Section of Structural Biology, Department of Medicine, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
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Valenzuela MA, Canales J, Corvalán AH, Quest AFG. Helicobacter pylori-induced inflammation and epigenetic changes during gastric carcinogenesis. World J Gastroenterol 2015; 21:12742-12756. [PMID: 26668499 PMCID: PMC4671030 DOI: 10.3748/wjg.v21.i45.12742] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 08/08/2015] [Accepted: 10/13/2015] [Indexed: 02/06/2023] Open
Abstract
The sequence of events associated with the development of gastric cancer has been described as “the gastric precancerous cascade”. This cascade is a dynamic process that includes lesions, such as atrophic gastritis, intestinal metaplasia and dysplasia. According to this model, Helicobacter pylori (H. pylori) infection targets the normal gastric mucosa causing non-atrophic gastritis, an initiating lesion that can be cured by clearing H. pylori with antibiotics or that may then linger in the case of chronic infection and progress to atrophic gastritis. The presence of virulence factors in the infecting H. pylori drives the carcinogenesis process. Independent epidemiological and animal studies have confirmed the sequential progression of these precancerous lesions. Particularly long-term follow-up studies estimated a risk of 0.1% for atrophic gastritis/intestinal metaplasia and 6% in case of dysplasia for the long-term development of gastric cancer. With this in mind, a better understanding of the genetic and epigenetic changes associated with progression of the cascade is critical in determining the risk of gastric cancer associated with H. pylori infection. In this review, we will summarize some of the most relevant mechanisms and focus predominantly but not exclusively on the discussion of gene promoter methylation and miRNAs in this context.
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Srivastava AK, Kumar V, Roy BK. Insights from the molecular docking of curcumin to the virulent factors of Helicobacter pylori. Bioinformation 2015; 11:447-53. [PMID: 26664028 PMCID: PMC4658642 DOI: 10.6026/97320630011447] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 10/01/2015] [Indexed: 12/11/2022] Open
Abstract
The domains of virulent (Ureα/β, VacA-p55, and CagA) factors of Helicobacter pylori play a pivotal role in developmental processes of numerous diseases including gastric cancer. The pharmacological role of curcumin indicates that it could regulate the signaling of virulent factors by interacting with active domains. However, the controlling mechanism of the curcumin interactions and the binding diversity on structural basis of virulent (Ureα/β, VacA-p55, and CagA) factors are unknown. Curcumin as therapeutic agent was filtered by using Lipinski rule׳s five and the druglikeness property for assessment of pharmacological properties. Here outcome of molecular docking presented the 3-D structure of curcumin complex, that interacted with especially conserved residues of target domains. The structure revealed that the curcumin complexation with domains of these proteins provided structural insight into the diverse nature of proteins (Ureα/β, VacA-p55, and CagA) recognition. In silico study elucidated that the broad specificity of curcumin was achieved by multiple binding mode mechanisms such as distinct hydrogen and hydrophobic interactions with involvement of binding energy. The higher score of curcumin in complexation with both subunits Ureα/β showed the stable binding, and less stability with VacA-p55 complexation with lower score. Curcumin exhibited good interaction with these targeted virulent factors, although extensive interactions of curcumin with Ureα/β subunits could have an important implication to prevent survival and colonisation of H. pylori in stomach.
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Affiliation(s)
| | - Vikas Kumar
- Department of Botany, Banaras Hindu University, Varanasi, 221005, India
| | - Bijoy Krishna Roy
- Department of Botany, Banaras Hindu University, Varanasi, 221005, India
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45
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da Costa DM, Pereira EDS, Rabenhorst SHB. What exists beyond cagA and vacA? Helicobacter pylori genes in gastric diseases. World J Gastroenterol 2015; 21:10563-72. [PMID: 26457016 PMCID: PMC4588078 DOI: 10.3748/wjg.v21.i37.10563] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 06/13/2015] [Accepted: 08/25/2015] [Indexed: 02/06/2023] Open
Abstract
Helicobacter pylori (H. pylori) infection is present in more than half the world's population and has been associated with several gastric disorders, such as gastritis, peptic ulceration, and gastric adenocarcinoma. The clinical outcome of this infection depends on host and bacterial factors where H. pylori virulence genes seem to play a relevant role. Studies of cagA and vacA genes established that they were determining factors in gastric pathogenesis. However, there are gastric cancer cases that are cagA-negative. Several other virulence genes have been searched for, but these genes remain less well known that cagA and vacA. Thus, this review aimed to establish which genes have been suggested as potentially relevant virulence factors for H. pylori-associated gastrointestinal diseases. We focused on the cag-pathogenicity island, genes with adherence and motility functions, and iceA based on the relevance shown in several studies in the literature.
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46
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Srivastava AK, Tewari M, Shukla HS, Roy BK. In SilicoProfiling of the Potentiality of Curcumin and Conventional Drugs for CagA Oncoprotein Inactivation. Arch Pharm (Weinheim) 2015; 348:548-55. [DOI: 10.1002/ardp.201400438] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 04/16/2015] [Accepted: 04/17/2015] [Indexed: 12/19/2022]
Affiliation(s)
| | - Mallika Tewari
- Department of Surgical Oncology; Banaras Hindu University; Varanasi India
| | - Hari S. Shukla
- Department of Surgical Oncology; Banaras Hindu University; Varanasi India
| | - Bijoy K. Roy
- Department of Botany; Banaras Hindu University; Varanasi India
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Ferreira RM, Machado JC, Figueiredo C. Clinical relevance of Helicobacter pylori vacA and cagA genotypes in gastric carcinoma. Best Pract Res Clin Gastroenterol 2014; 28:1003-15. [PMID: 25439067 DOI: 10.1016/j.bpg.2014.09.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 08/21/2014] [Accepted: 09/15/2014] [Indexed: 02/08/2023]
Abstract
Helicobacter pylori infection is the major etiological factor of gastric carcinoma. This disease is the result of a long, multistep, and multifactorial process, which occurs only in a small proportion of patients infected with H. pylori. Gastric carcinoma development is influenced by host genetic susceptibility factors, environmental factors, and H. pylori virulence. H. pylori is genetically highly variable, and variability that affects H. pylori virulence factors may be useful to identify strains with different degrees of pathogenicity. This review will focus on VacA and CagA that have polymorphic regions that impact their functional properties. The characterization of H. pylori vacA and cagA-associated could be useful for identifying patients at highest risk of disease, who could be offered H. pylori eradication therapy and who could be included in programs of more intensive surveillance in an attempt to reduce gastric carcinoma incidence.
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Affiliation(s)
- Rui M Ferreira
- Ipatimup - Institute of Molecular Pathology and Immunology of the University of Porto, Portugal
| | - José C Machado
- Ipatimup - Institute of Molecular Pathology and Immunology of the University of Porto, Portugal; Department of Pathology and Oncology, Faculty of Medicine of the University of Porto, Porto, Portugal
| | - Ceu Figueiredo
- Ipatimup - Institute of Molecular Pathology and Immunology of the University of Porto, Portugal; Department of Pathology and Oncology, Faculty of Medicine of the University of Porto, Porto, Portugal.
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Wang BB, Zhang FX, Ma Q. Helicobacter pylori-mediated autophagy and gastric carcinogenesis. Shijie Huaren Xiaohua Zazhi 2014; 22:4294-4300. [DOI: 10.11569/wcjd.v22.i28.4294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Helicobacter pylori (H. pylori) infection is closely related to the development of chronic gastritis, peptic ulcer, gastrointestinal metaplasia, and gastric carcinogenesis. H. pylori infection is multifactorial, including host genetic susceptibility, gene regulation, environmental factors and heterogeneity of H. pylori virulence factors. H. pylori adsorbs on the stomach wall through a variety of adhesion molecules, evades the host immune response through multiple virulence factors and defends against the killing effects of antibiotics killing through the capability of membrane resistance. Currently, the cooperative mechanisms between H. pylori and the human host have not yet been fully elucidated. Recent studies have shown that autophagy is an intracellular degradation process through the formation of double-membrane autophagosomes and plays an important role in H. pylori infection. Understanding of the process and molecular mechanisms of autophagy in host cells caused by H. pylori virulence factors will help better understand gastric carcinogenesis related to H. pylori-induced autophagy.
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TgaA, a VirB1-like component belonging to a putative type IV secretion system of Bifidobacterium bifidum MIMBb75. Appl Environ Microbiol 2014; 80:5161-9. [PMID: 24951779 DOI: 10.1128/aem.01413-14] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Bifidobacterium bifidum MIMBb75 is a human intestinal isolate demonstrated to be interactive with the host and efficacious as a probiotic. However, the molecular biology of this microorganism is yet largely unknown. For this reason, we undertook whole-genome sequencing of B. bifidum MIMBb75 to identify potential genetic factors that would explain the metabolic and probiotic attributes of this bacterium. Comparative genomic analysis revealed a 45-kb chromosomal region that comprises 19 putative genes coding for a potential type IV secretion system (T4SS). Thus, we undertook the initial characterization of this genetic region by studying the putative virB1-like gene, named tgaA. Gene tgaA encodes a peptidoglycan lytic enzyme containing two active domains: lytic murein transglycosylase (LT, cd00254.3) and cysteine- and histidine-dependent amidohydrolase/peptidase (CHAP, pfam05257.4). By means of several in vitro assays, we experimentally confirmed that protein TgaA, consistent with its computationally assigned role, has peptidoglycan lytic activity, which is principally associated to the LT domain. Furthermore, immunofluorescence and immunogold labeling showed that the protein TgaA is abundantly expressed on the cell surface of B. bifidum MIMBb75. According to the literature, the T4SSs, which have not been characterized before in bifidobacteria, can have important implications for bacterial cell-to-cell communication as well as cross talk with host cells, justifying the interest for further studies aimed at the investigation of this genetic region.
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