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Sharafutdinov I, Harrer A, Müsken M, Rottner K, Sticht H, Täger C, Naumann M, Tegtmeyer N, Backert S. Cortactin-dependent control of Par1b-regulated epithelial cell polarity in Helicobacter infection. Cell Insight 2024; 3:100161. [PMID: 38646547 PMCID: PMC11033139 DOI: 10.1016/j.cellin.2024.100161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 03/01/2024] [Accepted: 03/02/2024] [Indexed: 04/23/2024]
Abstract
Cell polarity is crucial for gastric mucosal barrier integrity and mainly regulated by polarity-regulating kinase partitioning-defective 1b (Par1b). During infection, the carcinogen Helicobacter pylori hijacks Par1b via the bacterial oncoprotein CagA leading to loss of cell polarity, but the precise molecular mechanism is not fully clear. Here we discovered a novel function of the actin-binding protein cortactin in regulating Par1b, which forms a complex with cortactin and the tight junction protein zona occludens-1 (ZO-1). We found that serine phosphorylation at S405/418 and the SH3 domain of cortactin are important for its interaction with both Par1b and ZO-1. Cortactin knockout cells displayed disturbed Par1b cellular localization and exhibited morphological abnormalities that largely compromised transepithelial electrical resistance, epithelial cell polarity, and apical microvilli. H. pylori infection promoted cortactin/Par1b/ZO-1 abnormal interactions in the tight junctions in a CagA-dependent manner. Infection of human gastric organoid-derived mucosoids supported these observations. We therefore hypothesize that CagA disrupts gastric epithelial cell polarity by hijacking cortactin, and thus Par1b and ZO-1, suggesting a new signaling pathway for the development of gastric cancer by Helicobacter.
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Affiliation(s)
- Irshad Sharafutdinov
- Department of Biology, Division of Microbiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, D-91058, Erlangen, Germany
| | - Aileen Harrer
- Department of Biology, Division of Microbiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, D-91058, Erlangen, Germany
| | - Mathias Müsken
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, D-38124, Braunschweig, Germany
| | - Klemens Rottner
- Department of Cell Biology, Helmholtz Centre for Infection Research, D-38124, Braunschweig, Germany
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, D-38106, Braunschweig, Germany
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, D-91054, Erlangen, Germany
| | - Christian Täger
- Otto von Guericke University, Institute of Experimental Internal Medicine, Medical Faculty, D-39120, Magdeburg, Germany
| | - Michael Naumann
- Otto von Guericke University, Institute of Experimental Internal Medicine, Medical Faculty, D-39120, Magdeburg, Germany
| | - Nicole Tegtmeyer
- Department of Biology, Division of Microbiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, D-91058, Erlangen, Germany
| | - Steffen Backert
- Department of Biology, Division of Microbiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, D-91058, Erlangen, Germany
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Backert S, Tegtmeyer N, Horn AHC, Sticht H, Linz B. Two remarkable serine/leucine polymorphisms in Helicobacter pylori: functional importance for serine protease HtrA and adhesin BabA. Cell Commun Signal 2024; 22:250. [PMID: 38698410 PMCID: PMC11064359 DOI: 10.1186/s12964-024-01635-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Accepted: 04/25/2024] [Indexed: 05/05/2024] Open
Abstract
Single nucleotide polymorphisms (SNPs) account for significant genomic variability in microbes, including the highly diverse gastric pathogen Helicobacter pylori. However, data on the effects of specific SNPs in pathogen-host interactions are scarce. Recent functional studies unravelled how a serine/leucine polymorphism in serine protease HtrA affects the formation of proteolytically active trimers and modulates cleavage of host cell-to-cell junction proteins during infection. A similar serine/leucine mutation in the carbohydrate binding domain of the adhesin BabA controls binding of ABO blood group antigens, enabling binding of either only the short Lewis b/H antigens of blood group O or also the larger antigens of blood groups A and B. Here we summarize the functional importance of these two remarkable bacterial SNPs and their effect on the outcome of pathogen-host interactions.
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Affiliation(s)
- Steffen Backert
- Department Biology, Division of Microbiology, Friedrich-Alexander Universität Erlangen-Nürnberg, Staudtstr. 5, Erlangen, 91058, Germany.
| | - Nicole Tegtmeyer
- Department Biology, Division of Microbiology, Friedrich-Alexander Universität Erlangen-Nürnberg, Staudtstr. 5, Erlangen, 91058, Germany
| | - Anselm H C Horn
- Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Fahrstr. 17, Erlangen, 91054, Germany
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Fahrstr. 17, Erlangen, 91054, Germany
| | - Bodo Linz
- Department Biology, Division of Microbiology, Friedrich-Alexander Universität Erlangen-Nürnberg, Staudtstr. 5, Erlangen, 91058, Germany
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Sharafutdinov I, Tegtmeyer N, Rohde M, Olofsson A, Rehman ZU, Arnqvist A, Backert S. Campylobacter jejuni Surface-Bound Protease HtrA, but Not the Secreted Protease nor Protease in Shed Membrane Vesicles, Disrupts Epithelial Cell-to-Cell Junctions. Cells 2024; 13:224. [PMID: 38334616 PMCID: PMC10854787 DOI: 10.3390/cells13030224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 12/01/2023] [Accepted: 01/22/2024] [Indexed: 02/10/2024] Open
Abstract
Fundamental functions of the intestinal epithelium include the digestion of food, absorption of nutrients, and its ability to act as the first barrier against intruding microbes. Campylobacter jejuni is a major zoonotic pathogen accounting for a substantial portion of bacterial foodborne illnesses. The germ colonizes the intestines of birds and is mainly transmitted to humans through the consumption of contaminated poultry meat. In the human gastrointestinal tract, the bacterium triggers campylobacteriosis that can progress to serious secondary disorders, including reactive arthritis, inflammatory bowel disease and Guillain-Barré syndrome. We recently discovered that C. jejuni serine protease HtrA disrupts intestinal epithelial barrier functions via cleavage of the tight and adherens junction components occludin, claudin-8 and E-cadherin. However, it is unknown whether epithelial damage is mediated by the secreted soluble enzyme, by HtrA contained in shed outer-membrane vesicles (OMVs) or by another mechanism that has yet to be identified. In the present study, we investigated whether soluble recombinant HtrA and/or purified OMVs induce junctional damage to polarized intestinal epithelial cells compared to live C. jejuni bacteria. By using electron and confocal immunofluorescence microscopy, we show that HtrA-expressing C. jejuni bacteria trigger efficient junctional cell damage, but not soluble purified HtrA or HtrA-containing OMVs, not even at high concentrations far exceeding physiological levels. Instead, we found that only bacteria with active protein biosynthesis effectively cleave junctional proteins, which is followed by paracellular transmigration of C. jejuni through the epithelial cell layer. These findings shed new light on the pathogenic activities of HtrA and virulence strategies of C. jejuni.
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Affiliation(s)
- Irshad Sharafutdinov
- Department of Biology, Division of Microbiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, D-91058 Erlangen, Germany
| | - Nicole Tegtmeyer
- Department of Biology, Division of Microbiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, D-91058 Erlangen, Germany
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, Inhoffenstraße 7, D-38124 Braunschweig, Germany
| | - Annelie Olofsson
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
| | - Zia ur Rehman
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
| | - Anna Arnqvist
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
| | - Steffen Backert
- Department of Biology, Division of Microbiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, D-91058 Erlangen, Germany
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Pachathundikandi SK, Tegtmeyer N, Backert S. Masking of typical TLR4 and TLR5 ligands modulates inflammation and resolution by Helicobacter pylori. Trends Microbiol 2023; 31:903-915. [PMID: 37012092 DOI: 10.1016/j.tim.2023.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/28/2023] [Accepted: 03/13/2023] [Indexed: 04/03/2023]
Abstract
Helicobacter pylori is a paradigm of chronic bacterial infection and is associated with peptic ulceration and malignancies. H. pylori uses specific masking mechanisms to avoid canonical ligands from activating Toll-like receptors (TLRs), such as lipopolysaccharide (LPS) modification and specific flagellin sequences that are not detected by TLR4 and TLR5, respectively. Thus, it was believed for a long time that H. pylori evades TLR recognition as a crucial strategy for immune escape and bacterial persistence. However, recent data indicate that multiple TLRs are activated by H. pylori and play a role in the pathology. Remarkably, H. pylori LPS, modified through changes in acylation and phosphorylation, is mainly sensed by other TLRs (TLR2 and TLR10) and induces both pro- and anti-inflammatory responses. In addition, two structural components of the cag pathogenicity island-encoded type IV secretion system (T4SS), CagL and CagY, were shown to contain TLR5-activating domains. These domains stimulate TLR5 and enhance immunity, while LPS-driven TLR10 signaling predominantly activates anti-inflammatory reactions. Here, we discuss the specific roles of these TLRs and masking mechanisms during infection. Masking of typical TLR ligands combined with evolutionary shifting to other TLRs is unique for H. pylori and has not yet been described for any other species in the bacterial kingdom. Finally, we highlight the unmasked T4SS-driven activation of TLR9 by H. pylori, which mainly triggers anti-inflammatory responses.
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Affiliation(s)
- Suneesh Kumar Pachathundikandi
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Dept. of Biology, Chair of Microbiology, Staudtstr. 5, 91058 Erlangen, Germany; Babasaheb Bhimrao Ambedkar University, Dept. of Environmental Microbiology, School of Earth and Environmental Sciences, Vidya Vihar, Raebareli Road, Lucknow 226025, India
| | - Nicole Tegtmeyer
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Dept. of Biology, Chair of Microbiology, Staudtstr. 5, 91058 Erlangen, Germany
| | - Steffen Backert
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Dept. of Biology, Chair of Microbiology, Staudtstr. 5, 91058 Erlangen, Germany.
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Sharafutdinov I, Tegtmeyer N, Linz B, Rohde M, Vieth M, Tay ACY, Lamichhane B, Tuan VP, Fauzia KA, Sticht H, Yamaoka Y, Marshall BJ, Backert S. A single-nucleotide polymorphism in Helicobacter pylori promotes gastric cancer development. Cell Host Microbe 2023; 31:1345-1358.e6. [PMID: 37490912 DOI: 10.1016/j.chom.2023.06.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/23/2023] [Accepted: 06/27/2023] [Indexed: 07/27/2023]
Abstract
Single-nucleotide polymorphisms (SNPs) in various human genes are key factors in carcinogenesis. However, whether SNPs in bacterial pathogens are similarly crucial in cancer development is unknown. Here, we analyzed 1,043 genomes of the stomach pathogen Helicobacter pylori and pinpointed a SNP in the serine protease HtrA (position serine/leucine 171) that significantly correlates with gastric cancer. Our functional studies reveal that the 171S-to-171L mutation triggers HtrA trimer formation and enhances proteolytic activity and cleavage of epithelial junction proteins occludin and tumor-suppressor E-cadherin. 171L-type HtrA, but not 171S-HtrA-possessing H. pylori, inflicts severe epithelial damage, enhances injection of oncoprotein CagA into epithelial cells, increases NF-κB-mediated inflammation and cell proliferation through nuclear accumulation of β-catenin, and promotes host DNA double-strand breaks, collectively triggering malignant changes. These findings highlight the 171S/L HtrA mutation as a unique bacterial cancer-associated SNP and as a potential biomarker for risk predictions in H. pylori infections.
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Affiliation(s)
- Irshad Sharafutdinov
- Division of Microbiology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Nicole Tegtmeyer
- Division of Microbiology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Bodo Linz
- Division of Microbiology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Michael Vieth
- Institute of Pathology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Klinikum Bayreuth, 95445 Bayreuth, Germany
| | - Alfred Chin-Yen Tay
- Helicobacter Research Laboratory, Marshall Centre for Infectious Diseases Research and Training, School of Pathology and Laboratory Medicine, University of Western Australia, 6009 Perth, Australia
| | - Binit Lamichhane
- Helicobacter Research Laboratory, Marshall Centre for Infectious Diseases Research and Training, School of Pathology and Laboratory Medicine, University of Western Australia, 6009 Perth, Australia
| | - Vo Phuoc Tuan
- Department of Endoscopy, Choray Hospital, Ho Chi Minh, Vietnam; Department of Environmental and Preventive Medicine, Faculty of Medicine, Oita University, Yufu, Oita, Japan
| | - Kartika Afrida Fauzia
- Department of Environmental and Preventive Medicine, Faculty of Medicine, Oita University, Yufu, Oita, Japan; Department of Public Health and Preventive Medicine, Faculty of Medicine, Universitas Airlangga, Surabaya, Indonesia
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Yoshio Yamaoka
- Department of Environmental and Preventive Medicine, Faculty of Medicine, Oita University, Yufu, Oita, Japan; Department of Medicine, Gastroenterology and Hepatology Section, Baylor College of Medicine, Houston, TX 77030, USA
| | - Barry J Marshall
- Helicobacter Research Laboratory, Marshall Centre for Infectious Diseases Research and Training, School of Pathology and Laboratory Medicine, University of Western Australia, 6009 Perth, Australia; University of Western Australia, Marshall Centre, M504, Crawley, WA, Australia; Marshall Laboratory of Biomedical Engineering, School of Biomedical Engineering, Shenzhen University Health Science Center, Shenzhen, China
| | - Steffen Backert
- Division of Microbiology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany.
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Zarzecka U, Tegtmeyer N, Sticht H, Backert S. Trimer stability of Helicobacter pylori HtrA is regulated by a natural mutation in the protease domain. Med Microbiol Immunol 2023:10.1007/s00430-023-00766-9. [PMID: 37183214 DOI: 10.1007/s00430-023-00766-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 04/26/2023] [Indexed: 05/16/2023]
Abstract
The human pathogen Helicobacter pylori is a major risk factor for gastric disease development. Serine protease HtrA is an important bacterial virulence factor that cleaves the cell junction proteins occludin, claudin-8 and E-cadherin, which causes gastric tissue damage. Using casein zymography, we discovered that HtrA trimer stability varies in clinical H. pylori strains. Subsequent sequence analyses revealed that HtrA trimer stability correlated with the presence of leucine or serine residue at position 171. The importance of these amino acids in determining trimer stability was confirmed by leucine-to-serine swapping experiments using isogenic H. pylori mutant strains as well as recombinant HtrA proteins. In addition, this sequence position displays a high sequence variability among various bacterial species, but generally exhibits a preference for hydrophilic amino acids. This natural L/S171 polymorphism in H. pylori may affect the protease activity of HtrA during infection, which could be of clinical importance and may determine gastric disease development.
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Affiliation(s)
- Urszula Zarzecka
- Division of Microbiology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Nicole Tegtmeyer
- Division of Microbiology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Steffen Backert
- Division of Microbiology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
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Linz B, Sharafutdinov I, Tegtmeyer N, Backert S. Evolution and Role of Proteases in Campylobacter jejuni Lifestyle and Pathogenesis. Biomolecules 2023; 13:biom13020323. [PMID: 36830692 PMCID: PMC9953165 DOI: 10.3390/biom13020323] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/26/2023] [Accepted: 02/04/2023] [Indexed: 02/10/2023] Open
Abstract
Infection with the main human food-borne pathogen Campylobacter jejuni causes campylobacteriosis that accounts for a substantial percentage of gastrointestinal infections. The disease usually manifests as diarrhea that lasts for up to two weeks. C. jejuni possesses an array of peptidases and proteases that are critical for its lifestyle and pathogenesis. These include serine proteases Cj1365c, Cj0511 and HtrA; AAA+ group proteases ClpP, Lon and FtsH; and zinc-dependent protease PqqE, proline aminopeptidase PepP, oligopeptidase PepF and peptidase C26. Here, we review the numerous critical roles of these peptide bond-dissolving enzymes in cellular processes of C. jejuni that include protein quality control; protein transport across the inner and outer membranes into the periplasm, cell surface or extracellular space; acquisition of amino acids and biofilm formation and dispersal. In addition, we highlight their role as virulence factors that inflict intestinal tissue damage by promoting cell invasion and mediating cleavage of crucial host cell factors such as epithelial cell junction proteins. Furthermore, we reconstruct the evolution of these proteases in 34 species of the Campylobacter genus. Finally, we discuss to what extent C. jejuni proteases have initiated the search for inhibitor compounds as prospective novel anti-bacterial therapies.
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Affiliation(s)
- Bodo Linz
- Correspondence: ; Tel.: +49-(0)-9131-8528988
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Backert S, Linz B, Tegtmeyer N. Helicobacter pylori-Induced Host Cell DNA Damage and Genetics of Gastric Cancer Development. Curr Top Microbiol Immunol 2023; 444:185-206. [PMID: 38231219 DOI: 10.1007/978-3-031-47331-9_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
Gastric cancer is a very serious and deadly disease worldwide with about one million new cases every year. Most gastric cancer subtypes are associated with genetic and epigenetic aberrations caused by chromosome instability, microsatellite instability or Epstein-Barr virus infection. Another risk factor is an infection with Helicobacter pylori, which also triggers severe alterations in the host genome. This pathogen expresses an extraordinary repertoire of virulence determinants that take over control of important host cell signaling functions. In fact, H. pylori is a paradigm of persistent infection, chronic inflammation and cellular destruction. In particular, H. pylori profoundly induces chromosomal DNA damage by introducing double-strand breaks (DSBs) followed by genomic instability. DSBs appear in response to oxidative stress and pro-inflammatory transcription during the S-phase of the epithelial cell cycle, which mainly depends on the presence of the bacterial cag pathogenicity island (cagPAI)-encoded type IV secretion system (T4SS). This scenario is closely connected with the T4SS-mediated injection of ADP-glycero-β-D-manno-heptose (ADP-heptose) and oncoprotein CagA. While ADP-heptose links transcription factor NF-κB-induced innate immune signaling with RNA-loop-mediated DNA replication stress and introduction of DSBs, intracellular CagA targets the tumor suppressor BRCA1. The latter scenario promotes BRCAness, a disease characterized by the deficiency of effective DSB repair. In addition, genetic studies of patients demonstrated the presence of gastric cancer-associated single nucleotide polymorphisms (SNPs) in immune-regulatory and other genes as well as specific pathogenic germline variants in several crucial genes involved in homologous recombination and DNA repair, all of which are connected to H. pylori infection. Here we review the molecular mechanisms leading to chromosomal DNA damage and specific genetic aberrations in the presence or absence of H. pylori infection, and discuss their importance in gastric carcinogenesis.
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Affiliation(s)
- Steffen Backert
- Division of Microbiology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, 91058, Erlangen, Germany.
| | - Bodo Linz
- Division of Microbiology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, 91058, Erlangen, Germany
| | - Nicole Tegtmeyer
- Division of Microbiology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, 91058, Erlangen, Germany.
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Sharafutdinov I, Knorr J, Rottner K, Backert S, Tegtmeyer N. Cortactin: A universal host cytoskeletal target of Gram-negative and Gram-positive bacterial pathogens. Mol Microbiol 2022; 118:623-636. [PMID: 36396951 DOI: 10.1111/mmi.15002] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 11/04/2022] [Accepted: 11/07/2022] [Indexed: 11/19/2022]
Abstract
Pathogenic bacteria possess a great potential of causing infectious diseases and represent a serious threat to human and animal health. Understanding the molecular basis of infection development can provide new valuable strategies for disease prevention and better control. In host-pathogen interactions, actin-cytoskeletal dynamics play a crucial role in the successful adherence, invasion, and intracellular motility of many intruding microbial pathogens. Cortactin, a major cellular factor that promotes actin polymerization and other functions, appears as a central regulator of host-pathogen interactions and different human diseases including cancer development. Various important microbes have been reported to hijack cortactin signaling during infection. The primary regulation of cortactin appears to proceed via serine and/or tyrosine phosphorylation events by upstream kinases, acetylation, and interaction with various other host proteins, including the Arp2/3 complex, filamentous actin, the actin nucleation promoting factor N-WASP, focal adhesion kinase FAK, the large GTPase dynamin-2, the guanine nucleotide exchange factor Vav2, and the actin-stabilizing protein CD2AP. Given that many signaling factors can affect cortactin activities, several microbes target certain unique pathways, while also sharing some common features. Here we review our current knowledge of the hallmarks of cortactin as a major target for eminent Gram-negative and Gram-positive bacterial pathogens in humans.
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Affiliation(s)
- Irshad Sharafutdinov
- Department of Biology, Division of Microbiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Jakob Knorr
- Department of Biology, Division of Microbiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Klemens Rottner
- Department of Cell Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany.,Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
| | - Steffen Backert
- Department of Biology, Division of Microbiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Nicole Tegtmeyer
- Department of Biology, Division of Microbiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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Tegtmeyer N, Linz B, Yamaoka Y, Backert S. Unique TLR9 Activation by Helicobacter pylori Depends on the cag T4SS, But Not on VirD2 Relaxases or VirD4 Coupling Proteins. Curr Microbiol 2022; 79:121. [PMID: 35239059 PMCID: PMC8894178 DOI: 10.1007/s00284-022-02813-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 02/15/2022] [Indexed: 11/30/2022]
Abstract
The genomes of the gastric bacterial pathogen Helicobacter pylori harbor multiple type-IV secretion systems (T4SSs). Here we analyzed components of three T4SSs, the cytotoxin-associated genes (cag) T4SS, TFS3 and TFS4. The cag T4SS delivers the effector protein CagA and the LPS-metabolite ADP-heptose into gastric epithelial cells, which plays a pivotal role in chronic infection and development of gastric disease. In addition, the cag T4SS was reported to facilitate conjugative transport of chromosomal bacterial DNA into the host cell cytoplasm, where injected DNA activates intracellular toll-like receptor 9 (TLR9) and triggers anti-inflammatory signaling. Canonical DNA-delivering T4SSs in a variety of bacteria are composed of 11 VirB proteins (VirB1-11) which assemble and engage VirD2 relaxase and VirD4 coupling proteins that mediate DNA processing and guiding of the covalently bound DNA through the T4SS channel. Nevertheless, the role of the latter components in H. pylori is unclear. Here, we utilized isogenic knockout mutants of various virB (virB9 and virB10, corresponding to cagX and cagY), virD2 (rlx1 and rlx2), virD4 (cag5, traG1/2) and xerD recombinase genes in H. pylori laboratory strain P12 and studied their role in TLR9 activation by reporter assays. While inactivation of the structural cag T4SS genes cagX and cagY abolished TLR9 activation, the deletion of rlx1, rlx2, cag5, traG or xerD genes had no effect. The latter mutants activated TLR9 similar to wild-type bacteria, suggesting the presence of a unique non-canonical T4SS-dependent mechanism of TLR9 stimulation by H. pylori that is not mediated by VirD2, VirD4 and XerD proteins. These findings were confirmed by the analysis of TLR9 activation by H. pylori strains of worldwide origin that possess different sets of T4SS genes. The exact mechanism of TLR9 activation should be explored in future studies.
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Affiliation(s)
- Nicole Tegtmeyer
- Department of Biology, Chair of Microbiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, 91058, Erlangen, Germany
| | - Bodo Linz
- Department of Biology, Chair of Microbiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, 91058, Erlangen, Germany
| | - Yoshio Yamaoka
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Yufu, Japan
| | - Steffen Backert
- Department of Biology, Chair of Microbiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, 91058, Erlangen, Germany.
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Tegtmeyer N, Soltan Esmaeili D, Sharafutdinov I, Knorr J, Naumann M, Alter T, Backert S. Importance of cortactin for efficient epithelial NF-ĸB activation by Helicobacter pylori, Salmonella enterica and Pseudomonas aeruginosa, but not Campylobacter spp. Eur J Microbiol Immunol (Bp) 2022; 11:95-103. [PMID: 35060920 PMCID: PMC8830411 DOI: 10.1556/1886.2021.00023] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 12/27/2021] [Indexed: 12/17/2022] Open
Abstract
Abstract
Transcription factors of the nuclear factor kappa‐light‐chain‐enhancer of activated B cells (NF-ĸB) family control important signaling pathways in the regulation of the host innate immune system. Various bacterial pathogens in the human gastrointestinal tract induce NF-ĸB activity and provoke pro-inflammatory signaling events in infected epithelial cells. NF-ĸB activation requires the phosphorylation-dependent proteolysis of inhibitor of ĸB (IĸB) molecules including the NF-ĸB precursors through ubiquitin-mediated proteolysis. The canonical NF-ĸB pathway merges on IĸB kinases (IKKs), which are required for signal transduction. Using CRISPR-Cas9 technology, secreted embryonic alkaline phosphatase (SEAP) reporter assays and cytokine enzyme-linked immunosorbent assay (ELISA), we demonstrate that the actin-binding protein cortactin is involved in NF-ĸB activation and subsequent interleukin-8 (IL-8) production upon infection by Helicobacter pylori, Salmonella enterica and Pseudomonas aeruginosa. Our data indicate that cortactin is needed to efficiently activate the c-Sarcoma (Src) kinase, which can positively stimulate NF-ĸB during infection. In contrast, cortactin is not involved in activation of NF-ĸB and IL-8 expression upon infection with Campylobacter species C. jejuni, C. coli or C. consisus, suggesting that Campylobacter species pluralis (spp.) induce a different signaling pathway upstream of cortactin to trigger the innate immune response.
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Affiliation(s)
- Nicole Tegtmeyer
- Department of Biology, Division of Microbiology, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Germany
| | - Delara Soltan Esmaeili
- Department of Biology, Division of Microbiology, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Germany
| | - Irshad Sharafutdinov
- Department of Biology, Division of Microbiology, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Germany
| | - Jakob Knorr
- Department of Biology, Division of Microbiology, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Germany
| | - Michael Naumann
- Institute of Experimental Internal Medicine, Medical Faculty, Otto von Guericke University Magdeburg, Germany
| | - Thomas Alter
- Institute of Food Safety and Food Hygiene, Centre for Veterinary Public Health, Freie Universität Berlin, Germany
| | - Steffen Backert
- Department of Biology, Division of Microbiology, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Germany
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Sharafutdinov I, Backert S, Tegtmeyer N. The Helicobacter pylori type IV secretion system upregulates epithelial cortactin expression by a CagA- and JNK-dependent pathway. Cell Microbiol 2021; 23:e13376. [PMID: 34197673 DOI: 10.1111/cmi.13376] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 06/18/2021] [Accepted: 06/28/2021] [Indexed: 12/11/2022]
Abstract
Cortactin represents an important actin-binding factor, which controls actin-cytoskeletal remodelling in host cells. In this way, cortactin has been shown to exhibit crucial functions both for cell movement and tumour cell invasion. In addition, the cortactin gene cttn is amplified in various cancer types of humans. Helicobacter pylori is the causative agent of multiple gastric diseases and represents a significant risk factor for the development of gastric adenocarcinoma. It has been repeatedly shown that H. pylori manipulates cancer-related signal transduction events in infected gastric epithelial cells such as the phosphorylation status of cortactin. In fact, H. pylori modifies the activity of cortactin's binding partners to stimulate changes in the actin-cytoskeleton, cell adhesion and motility. Here we show that H. pylori infection of cultured AGS and Caco-2 cells for 24-48 hr leads to the overexpression of cortactin by 2-3 fold at the protein level. We demonstrate that this activity requires the integrity of the type IV secretion system (T4SS) encoded by the cag pathogenicity island (cagPAI) as well as the translocated effector protein CagA. We further show that ectopic expression of CagA is sufficient to stimulate cortactin overexpression. Furthermore, phosphorylation of CagA at the EPIYA-repeat region is not required, suggesting that this CagA activity proceeds in a phosphorylation-independent fashion. Inhibitor studies further demonstrate that the involved signalling pathway comprises the mitogen-activated protein kinase JNK (c-Jun N-terminal kinase), but not ERK1/2 or p38. Taken together, using H. pylori as a model system, this study discovered a previously unrecognised cortactin activation cascade by a microbial pathogen. We suggest that H. pylori targets cortactin to manipulate the cellular architecture and epithelial barrier functions that can impact gastric cancer development. TAKE AWAYS: Helicobacter pylori infection induces overexpression of cortactin at the protein level Cortactin upregulation requires the T4SS and effector protein CagA Ectopic expression of CagA is sufficient to stimulate cortactin overexpression Overexpression of cortactin proceeds CagA phosphorylation-independent The involved host cell signalling pathway comprises the MAP kinase JNK.
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Affiliation(s)
- Irshad Sharafutdinov
- Department of Biology, Division of Microbiology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, 91058, Germany
| | - Steffen Backert
- Department of Biology, Division of Microbiology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, 91058, Germany
| | - Nicole Tegtmeyer
- Department of Biology, Division of Microbiology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, 91058, Germany
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Knorr J, Sharafutdinov I, Fiedler F, Soltan Esmaeili D, Rohde M, Rottner K, Backert S, Tegtmeyer N. Cortactin Is Required for Efficient FAK, Src and Abl Tyrosine Kinase Activation and Phosphorylation of Helicobacter pylori CagA. Int J Mol Sci 2021; 22:ijms22116045. [PMID: 34205064 PMCID: PMC8199859 DOI: 10.3390/ijms22116045] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 05/28/2021] [Accepted: 06/01/2021] [Indexed: 12/11/2022] Open
Abstract
Cortactin is a well-known regulatory protein of the host actin cytoskeleton and represents an attractive target of microbial pathogens like Helicobacter pylori. H. pylori manipulates cortactin's phosphorylation status by type-IV secretion-dependent injection of its virulence protein CagA. Multiple host tyrosine kinases, like FAK, Src, and Abl, are activated during infection, but the pathway(s) involved is (are) not yet fully established. Among them, Src and Abl target CagA and stimulate tyrosine phosphorylation of the latter at its EPIYA-motifs. To investigate the role of cortactin in more detail, we generated a CRISPR/Cas9 knockout of cortactin in AGS gastric epithelial cells. Surprisingly, we found that FAK, Src, and Abl kinase activities were dramatically downregulated associated with widely diminished CagA phosphorylation in cortactin knockout cells compared to the parental control. Together, we report here a yet unrecognized cortactin-dependent signaling pathway involving FAK, Src, and Abl activation, and controlling efficient phosphorylation of injected CagA during infection. Thus, the cortactin status could serve as a potential new biomarker of gastric cancer development.
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Affiliation(s)
- Jakob Knorr
- Department of Biology, Division of Microbiology, Friedrich-Alexander University of Erlangen-Nuremberg, 91058 Erlangen, Germany; (J.K.); (I.S.); (F.F.); (D.S.E.); (S.B.)
| | - Irshad Sharafutdinov
- Department of Biology, Division of Microbiology, Friedrich-Alexander University of Erlangen-Nuremberg, 91058 Erlangen, Germany; (J.K.); (I.S.); (F.F.); (D.S.E.); (S.B.)
| | - Florian Fiedler
- Department of Biology, Division of Microbiology, Friedrich-Alexander University of Erlangen-Nuremberg, 91058 Erlangen, Germany; (J.K.); (I.S.); (F.F.); (D.S.E.); (S.B.)
| | - Delara Soltan Esmaeili
- Department of Biology, Division of Microbiology, Friedrich-Alexander University of Erlangen-Nuremberg, 91058 Erlangen, Germany; (J.K.); (I.S.); (F.F.); (D.S.E.); (S.B.)
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany;
| | - Klemens Rottner
- Department of Cell Biology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany;
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany
| | - Steffen Backert
- Department of Biology, Division of Microbiology, Friedrich-Alexander University of Erlangen-Nuremberg, 91058 Erlangen, Germany; (J.K.); (I.S.); (F.F.); (D.S.E.); (S.B.)
| | - Nicole Tegtmeyer
- Department of Biology, Division of Microbiology, Friedrich-Alexander University of Erlangen-Nuremberg, 91058 Erlangen, Germany; (J.K.); (I.S.); (F.F.); (D.S.E.); (S.B.)
- Correspondence:
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Sharafutdinov I, Esmaeili DS, Harrer A, Tegtmeyer N, Sticht H, Backert S. Campylobacter jejuni Serine Protease HtrA Cleaves the Tight Junction Component Claudin-8. Front Cell Infect Microbiol 2020; 10:590186. [PMID: 33364202 PMCID: PMC7752809 DOI: 10.3389/fcimb.2020.590186] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 10/27/2020] [Indexed: 12/12/2022] Open
Abstract
Campylobacter jejuni express the high temperature requirement protein A (HtrA), a secreted serine protease, which is implicated in virulence properties of the pathogen. Previous studies have shown that C. jejuni HtrA can cleave the epithelial transmembrane proteins occludin and E-cadherin in the tight and adherens junctions, respectively. In the present report, we studied the interaction of HtrA with another human tight junction protein, claudin-8. Confocal immunofluorescence experiments have shown that C. jejuni infection of the intestinal polarized epithelial cells in vitro leads to a relocation of claudin-8. Wild-type C. jejuni induced the downregulation of claudin-8 signals in the tight junctions and an accumulation of claudin-8 agglomerates in the cytoplasm, which were not seen during infection with isogenic ΔhtrA knockout deletion or protease-inactive S197A point mutants. Western blotting of protein samples from infected vs. uninfected cells revealed that an 18-kDa carboxy-terminal fragment is cleaved-off from the 26-kDa full-length claudin-8 protein, but not during infection with the isogenic ΔhtrA mutant. These results were confirmed by in vitro cleavage assays using the purified recombinant C. jejuni HtrA and human claudin-8 proteins. Recombinant HtrA cleaved purified claudin-8 in vitro giving rise to the same 18-kDa sized carboxy-terminal cleavage product. Mapping studies revealed that HtrA cleavage occurs in the first extracellular loop of claudin-8. Three-dimensional modeling of the claudin-8 structure identified an exposed HtrA cleavage site between the amino acids alanine 58 and asparagine 59, which is in well agreement with the mapping studies. Taken together, HtrA operates as a secreted virulence factor targeting multiple proteins both in the tight and adherens junctions. This strategy may help the bacteria to open the cell-to-cell junctions, and to transmigrate across the intestinal epithelium by a paracellular mechanism and establish an acute infection.
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Affiliation(s)
- Irshad Sharafutdinov
- Department of Biology, Division of Microbiology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Delara Soltan Esmaeili
- Department of Biology, Division of Microbiology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Aileen Harrer
- Department of Biology, Division of Microbiology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Nicole Tegtmeyer
- Department of Biology, Division of Microbiology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Steffen Backert
- Department of Biology, Division of Microbiology, University of Erlangen-Nuremberg, Erlangen, Germany
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15
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Heimesaat MM, Schmidt AM, Mousavi S, Escher U, Tegtmeyer N, Wessler S, Gadermaier G, Briza P, Hofreuter D, Bereswill S, Backert S. Peptidase PepP is a novel virulence factor of Campylobacter jejuni contributing to murine campylobacteriosis. Gut Microbes 2020; 12:1770017. [PMID: 32584649 PMCID: PMC7524167 DOI: 10.1080/19490976.2020.1770017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 05/05/2020] [Indexed: 02/07/2023] Open
Abstract
Mechanisms of host-pathogen interactions resulting in immunopathological responses upon human Campylobacter jejuni infection are not completely understood, but the recent availability of murine infection models mimicking key features of campylobacteriosis helps solving this dilemma. During a screen for proteases expressed by C. jejuni, we identified a peptidase of the M24 family as a potential novel virulence factor, which was named PepP. The gene is strongly conserved in various Campylobacter species. A constructed deletion mutant ΔpepP of C. jejuni strain 81-176 grew as efficiently compared to isogenic wild-type (WT) or pepP complemented bacteria. To shed light on the potential role of this protease in mediating immunopathological responses in the mammalian host, we perorally challenged microbiota-depleted IL-10-/- mice with these strains. All strains stably colonized the murine gastrointestinal tract with comparably high loads. Remarkably, pepP deficiency was associated with less severe induced malaise, with less distinct apoptotic and innate immune cell responses, but also with more pronounced proliferative/regenerative epithelial cell responses in the large intestine at d6post-infection. Furthermore, pro-inflammatory mediators were lower in the colon, ileum, and mesenteric lymph nodes of mice that had been challenged with the ΔpepP mutant compared to the WT or pepP complemented strains. This also held true for extra-intestinal organs including liver, kidneys, and lungs, and, strikingly, to systemic compartments. Taken together, protease PepP is a novel virulence determinant involved in mediating campylobacteriosis. The finding that apoptosis in the colon is significantly diminished in mice infected with the pepP mutant highlights the epithelial layer as the first and main target of PepP in the intestine.
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Affiliation(s)
- Markus M. Heimesaat
- Institute of Microbiology, Infectious Diseases and Immunology, Gastrointestinal Microbiology Research Group, Charité - University Medicine Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, And Berlin Institute of Health, Berlin, Germany
| | - Anna-Maria Schmidt
- Institute of Microbiology, Infectious Diseases and Immunology, Gastrointestinal Microbiology Research Group, Charité - University Medicine Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, And Berlin Institute of Health, Berlin, Germany
| | - Soraya Mousavi
- Institute of Microbiology, Infectious Diseases and Immunology, Gastrointestinal Microbiology Research Group, Charité - University Medicine Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, And Berlin Institute of Health, Berlin, Germany
| | - Ulrike Escher
- Institute of Microbiology, Infectious Diseases and Immunology, Gastrointestinal Microbiology Research Group, Charité - University Medicine Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, And Berlin Institute of Health, Berlin, Germany
| | - Nicole Tegtmeyer
- Division of Microbiology, Department of Biology, Friedrich Alexander University Erlangen/Nuremberg, Erlangen, Germany
| | - Silja Wessler
- Department of Biosciences, Paris Lodron University of Salzburg, Salzburg, Austria
| | - Gabriele Gadermaier
- Department of Biosciences, Paris Lodron University of Salzburg, Salzburg, Austria
| | - Peter Briza
- Department of Biosciences, Paris Lodron University of Salzburg, Salzburg, Austria
| | - Dirk Hofreuter
- Department of Biological Safety, German Federal Institute for Risk Assessment (Bfr), Berlin, Germany
| | - Stefan Bereswill
- Institute of Microbiology, Infectious Diseases and Immunology, Gastrointestinal Microbiology Research Group, Charité - University Medicine Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, And Berlin Institute of Health, Berlin, Germany
| | - Steffen Backert
- Division of Microbiology, Department of Biology, Friedrich Alexander University Erlangen/Nuremberg, Erlangen, Germany
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Tegtmeyer N, Backert S. Different roles of integrin-β1 and integrin-αv for type IV secretion of CagA versus cell elongation phenotype and cell lifting by Helicobacter pylori. PLoS Pathog 2020; 16:e1008135. [PMID: 32692784 PMCID: PMC7373265 DOI: 10.1371/journal.ppat.1008135] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 10/07/2019] [Indexed: 12/15/2022] Open
Affiliation(s)
- Nicole Tegtmeyer
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, Erlangen, Germany
- * E-mail: (NT); (SB)
| | - Steffen Backert
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, Erlangen, Germany
- * E-mail: (NT); (SB)
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17
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Fischer W, Tegtmeyer N, Stingl K, Backert S. Four Chromosomal Type IV Secretion Systems in Helicobacter pylori: Composition, Structure and Function. Front Microbiol 2020; 11:1592. [PMID: 32754140 PMCID: PMC7366825 DOI: 10.3389/fmicb.2020.01592] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 06/18/2020] [Indexed: 12/14/2022] Open
Abstract
The pathogenic bacterium Helicobacter pylori is genetically highly diverse and a major risk factor for the development of peptic ulcer disease and gastric adenocarcinoma in humans. During evolution, H. pylori has acquired multiple type IV secretion systems (T4SSs), and then adapted for various purposes. These T4SSs represent remarkable molecular transporter machines, often associated with an extracellular pilus structure present in many bacteria, which are commonly composed of multiple structural proteins spanning the inner and outer membranes. By definition, these T4SSs exhibit central functions mediated through the contact-dependent conjugative transfer of mobile DNA elements, the contact-independent release and uptake of DNA into and from the extracellular environment as well as the secretion of effector proteins in mammalian host target cells. In recent years, numerous features on the molecular functionality of these T4SSs were disclosed. H. pylori encodes up to four T4SSs on its chromosome, namely the Cag T4SS present in the cag pathogenicity island (cagPAI), the ComB system, as well as the Tfs3 and Tfs4 T4SSs, some of which exhibit unique T4SS functions. The Cag T4SS facilitates the delivery of the CagA effector protein and pro-inflammatory signal transduction through translocated ADP-heptose and chromosomal DNA, while various structural pilus proteins can target host cell receptors such as integrins or TLR5. The ComB apparatus mediates the import of free DNA from the extracellular milieu, whereas Tfs3 may accomplish the secretion or translocation of effector protein CtkA. Both Tfs3 and Tfs4 are furthermore presumed to act as conjugative DNA transfer machineries due to the presence of tyrosine recombinases with cognate recognition sequences, conjugational relaxases, and potential origins of transfer (oriT) found within the tfs3 and tfs4 genome islands. In addition, some extrachromosomal plasmids, transposons and phages have been discovered in multiple H. pylori isolates. The genetic exchange mediated by DNA mobilization events of chromosomal genes and plasmids combined with recombination events could account for much of the genetic diversity found in H. pylori. In this review, we highlight our current knowledge on the four T4SSs and the involved mechanisms with consequences for H. pylori adaptation to the hostile environment in the human stomach.
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Affiliation(s)
- Wolfgang Fischer
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Medizinische Fakultät, LMU München, Munich, Germany
| | - Nicole Tegtmeyer
- Department Biologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Kerstin Stingl
- Department of Biological Safety, National Reference Laboratory for Campylobacter, German Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | - Steffen Backert
- Department Biologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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Emidio NB, Baik H, Lee D, Stürmer R, Heuer J, Elliott AG, Blaskovich MAT, Haupenthal K, Tegtmeyer N, Hoffmann W, Schroeder CI, Muttenthaler M. Chemical synthesis of human trefoil factor 1 (TFF1) and its homodimer provides novel insights into their mechanisms of action. Chem Commun (Camb) 2020; 56:6420-6423. [PMID: 32391824 PMCID: PMC7116170 DOI: 10.1039/d0cc02321c] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
TFF1 is a key peptide for gastrointestinal protection and repair. Its molecular mechanism of action remains poorly understood with synthetic intractability a recognised bottleneck. Here we describe the synthesis of TFF1 and its homodimer and their interactions with mucins and Helicobacter pylori. Synthetic access to TFF1 is an important milestone for probe and therapeutic development.
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Affiliation(s)
- Nayara Braga Emidio
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, 4072, Australia
| | - Hayeon Baik
- Institute of Biological Chemistry Faculty of Chemistry, University of Vienna, Währingerstr. 38, Vienna, 1090, Austria
| | - David Lee
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, 4072, Australia
| | - René Stürmer
- Institute of Molecular Biology and Medicinal Chemistry, Otto-von-Guericke- University Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany
| | - Jörn Heuer
- Institute of Molecular Biology and Medicinal Chemistry, Otto-von-Guericke- University Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany
| | - Alysha G. Elliott
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, 4072, Australia
| | - Mark A. T. Blaskovich
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, 4072, Australia
| | - Katharina Haupenthal
- Institute of Molecular Biology and Medicinal Chemistry, Otto-von-Guericke- University Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany
| | - Nicole Tegtmeyer
- Division of Microbiology, Department of Biology, Friedrich-Alexander-University Erlangen-Nürnberg Staudtstr. 5, 91058 Erlangen, Germany
| | - Werner Hoffmann
- Institute of Molecular Biology and Medicinal Chemistry, Otto-von-Guericke- University Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany
| | - Christina I. Schroeder
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, 4072, Australia
- National Cancer Institute, National Institutes of Health, Frederick, MD, 21702, USA
| | - Markus Muttenthaler
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, 4072, Australia
- Institute of Biological Chemistry Faculty of Chemistry, University of Vienna, Währingerstr. 38, Vienna, 1090, Austria
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19
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Tegtmeyer N, Ghete TD, Schmitt V, Remmerbach T, Cortes MCC, Bondoc EM, Graf HL, Singer BB, Hirsch C, Backert S. Type IV secretion of Helicobacter pylori CagA into oral epithelial cells is prevented by the absence of CEACAM receptor expression. Gut Pathog 2020; 12:25. [PMID: 32435278 PMCID: PMC7222478 DOI: 10.1186/s13099-020-00363-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 05/09/2020] [Indexed: 02/07/2023] Open
Abstract
Background Helicobacter pylori typically colonizes the human stomach, but it can occasionally be detected in the oral cavity of infected persons. Clinical outcome as a result of gastric colonization depends on presence of the pathogenicity island cagPAI that encodes a type-IV secretion system (T4SS) for translocation of the effector protein CagA and ADP-heptose. Upon injection into target cells, CagA is phosphorylated, which can be demonstrated by in vitro infection of the gastric epithelial cell line AGS, resulting in cell elongation. Here we investigated whether H. pylori can exert these responses during interaction with cells from the oral epithelium. To this purpose, three oral epithelial cell lines, HN, CAL-27 and BHY, were infected with various virulent wild-type H. pylori strains, and CagA delivery and ADP-heptose-mediated pro-inflammatory responses were monitored. Results All three oral cell lines were resistant to elongation upon infection, despite similar bacterial binding capabilities. Moreover, T4SS-dependent CagA injection was absent. Resistance to CagA delivery was shown to be due to absence of CEACAM expression in these cell lines, while these surface molecules have recently been recognized as H. pylori T4SS receptors. Lack of CEACAM expression in HN, CAL-27 and BHY cells was overcome by genetic introduction of either CEACAM1, CEACAM5, or CEACAM6, which in each of the cell lines was proven sufficient to facilitate CagA delivery and phosphorylation upon H. pylori infection to levels similar to those observed with the gastric AGS cells. Pro-inflammatory responses, as measured by interleukin-8 ELISA, were induced to high levels in each cell line and CEACAM-independent. Conclusions These results show that lack of CEACAM receptors on the surface of the oral epithelial cells was responsible for resistance to H. pylori CagA-dependent pathogenic activities, and confirms the important role for the T4SS-dependent interaction of these receptors with H. pylori in the gastric epithelium.
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Affiliation(s)
- Nicole Tegtmeyer
- 1Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen, Staudtstrasse 5, 91058 Erlangen, Germany
| | - Tabita Denisia Ghete
- 1Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen, Staudtstrasse 5, 91058 Erlangen, Germany
| | - Verena Schmitt
- 2Medical Faculty, Institute of Anatomy, University of Duisburg-Essen, Hufelandstrasse 55, 45147 Essen, Germany
| | - Torsten Remmerbach
- 3Division of Clinical and Experimental Oral Medicine, Department of OMF-Surgery, Leipzig University Hospital, University of Leipzig, Leipzig, Germany
| | - Maria Celeste C Cortes
- 4Center for Basic Science Research (CBSR), Research and Biotechnology (R&B), St. Luke's Medical Center, Quezon City, Philippines
| | - Edgardo M Bondoc
- 5Institute for Digestive and Liver Diseases, St. Luke's Medical Center, Quezon City, Philippines
| | - Hans-Ludwig Graf
- 6Department of Oral, Maxillary, Facial and Reconstructive Plastic Surgery, University Hospital of Leipzig, Leipzig, Germany
| | - Bernhard B Singer
- 2Medical Faculty, Institute of Anatomy, University of Duisburg-Essen, Hufelandstrasse 55, 45147 Essen, Germany
| | - Christian Hirsch
- 7Department of Paediatric Dentistry, University School of Dental Medicine, University of Leipzig, Leipzig, Germany
| | - Steffen Backert
- 1Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen, Staudtstrasse 5, 91058 Erlangen, Germany
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Knorr J, Backert S, Tegtmeyer N. SHP2-Independent Tyrosine Dephosphorylation of Cortactin and Vinculin during Infection with Helicobacter pylori. Eur J Microbiol Immunol (Bp) 2020; 10:20-27. [PMID: 32363035 PMCID: PMC7182119 DOI: 10.1556/1886.2020.00001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 01/20/2020] [Indexed: 02/06/2023] Open
Abstract
The gastric pathogen Helicobacter pylori colonizes approximately half of the human world population. The bacterium injects the effector protein cytotoxin associated gene A (CagA) via a type-IV secretion system into host epithelial cells, where the protein becomes phosphorylated at specific EPIYA-motifs by cellular kinases. Inside the host cell, CagA can interact with over 25 different proteins in both phosphorylation-dependent and phosphorylation-independent manners, resulting in manipulation of host-cell signaling pathways. During the course of an H. pylori infection, certain host-cell proteins undergo tyrosine dephosphorylation in a CagA-dependent manner, including the actin-binding proteins cortactin and vinculin. A predominant response of intracellular CagA is the binding and activation of tyrosine phosphatase, the human Src-homology-region-2-domain-containing-phosphatase-2 (SHP2). Here, we considered the possibility that activated SHP2 might be responsible for the dephosphorylation of cortactin and vinculin. To investigate this, phosphatase inhibitor studies were performed. Additionally, a complete knockout mutant of SHP2 in AGS cells was created by CRISPR/Cas9 technology, and these cells were infected with H. pylori. However, neither the presence of an inhibitor nor the inactivation of SHP2 prevented the dephosphorylation of cortactin and vinculin upon CagA delivery. Tyrosine dephosphorylation of these proteins is therefore independent of SHP2 and instead must be caused by another, as yet unidentified, protein tyrosine phosphatase.
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Sharafutdinov I, Backert S, Tegtmeyer N. Cortactin: A Major Cellular Target of the Gastric Carcinogen Helicobacter pylori. Cancers (Basel) 2020; 12:E159. [PMID: 31936446 PMCID: PMC7017262 DOI: 10.3390/cancers12010159] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 01/04/2020] [Accepted: 01/06/2020] [Indexed: 12/19/2022] Open
Abstract
Cortactin is an actin binding protein and actin nucleation promoting factor regulating cytoskeletal rearrangements in nearly all eukaryotic cell types. From this perspective, cortactin poses an attractive target for pathogens to manipulate a given host cell to their own benefit. One of the pathogens following this strategy is Helicobacter pylori, which can cause a variety of gastric diseases and has been shown to be the major risk factor for the onset of gastric cancer. During infection of gastric epithelial cells, H. pylori hijacks the cellular kinase signaling pathways, leading to the disruption of key cell functions. Specifically, by overruling the phosphorylation status of cortactin, H. pylori alternates the activity of molecular interaction partners of this important protein, thereby manipulating the performance of actin-cytoskeletal rearrangements and cell movement. In addition, H. pylori utilizes a unique mechanism to activate focal adhesion kinase, which subsequently prevents host epithelial cells from extensive lifting from the extracellular matrix in order to achieve chronic infection in the human stomach.
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Affiliation(s)
| | | | - Nicole Tegtmeyer
- Division of Microbiology, Department of Biology, Friedrich Alexander University Erlangen-Nuremberg, Staudtstr. 5, D-91058 Erlangen, Germany; (I.S.); (S.B.)
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Braga Emidio N, Baik H, Lee D, Stürmer R, Heuer J, Elliott AG, Blaskovich MAT, Haupenthal K, Tegtmeyer N, Hoffmann W, Schroeder CI, Muttenthaler M. Correction: Chemical synthesis of human trefoil factor 1 (TFF1) and its homodimer provides novel insights into their mechanisms of action. Chem Commun (Camb) 2020; 56:7049. [DOI: 10.1039/d0cc90250k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Correction for ‘Chemical synthesis of human trefoil factor 1 (TFF1) and its homodimer provides novel insights into their mechanisms of action’ by Nayara Braga Emidio et al., Chem. Commun., 2020, DOI: 10.1039/D0CC02321C.
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Pachathundikandi SK, Tegtmeyer N, Arnold IC, Lind J, Neddermann M, Falkeis-Veits C, Chattopadhyay S, Brönstrup M, Tegge W, Hong M, Sticht H, Vieth M, Müller A, Backert S. T4SS-dependent TLR5 activation by Helicobacter pylori infection. Nat Commun 2019; 10:5717. [PMID: 31844047 PMCID: PMC6915727 DOI: 10.1038/s41467-019-13506-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 11/07/2019] [Indexed: 02/08/2023] Open
Abstract
Toll-like receptor TLR5 recognizes a conserved domain, termed D1, that is present in flagellins of several pathogenic bacteria but not in Helicobacter pylori. Highly virulent H. pylori strains possess a type IV secretion system (T4SS) for delivery of virulence factors into gastric epithelial cells. Here, we show that one of the H. pylori T4SS components, protein CagL, can act as a flagellin-independent TLR5 activator. CagL contains a D1-like motif that mediates adherence to TLR5+ epithelial cells, TLR5 activation, and downstream signaling in vitro. TLR5 expression is associated with H. pylori infection and gastric lesions in human biopsies. Using Tlr5-knockout and wild-type mice, we show that TLR5 is important for efficient control of H. pylori infection. Our results indicate that CagL, by activating TLR5, may modulate immune responses to H. pylori. Toll-like receptor TLR5 recognizes a domain, D1, that is present in flagellins of several pathogenic bacteria but not in Helicobacter pylori. Here, the authors show that TLR5 can be activated independently of flagellin by a component of the H. pylori type IV secretion system that contains a D1-like motif.
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Affiliation(s)
| | - Nicole Tegtmeyer
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | | | - Judith Lind
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Matthias Neddermann
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | | | - Sujay Chattopadhyay
- JIS Institute of Advanced Studies and Research, JIS University, Kolkata, 700091, India
| | - Mark Brönstrup
- Department of Chemical Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Werner Tegge
- Department of Chemical Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Minsun Hong
- Division of Biological Science and Technology, Yonsei University, Wonju, Republic of Korea
| | - Heinrich Sticht
- Institute of Biochemistry, Division of Bioinformatics, Friedrich Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Michael Vieth
- Institute for Pathology, Klinikum Bayreuth, Bayreuth, Germany
| | - Anne Müller
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Steffen Backert
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, Erlangen, Germany.
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Pachathundikandi SK, Gutiérrez-Escobar AJ, Tegtmeyer N. Tailor-Made Detection of Individual Phosphorylated and Non-Phosphorylated EPIYA-Motifs of Helicobacter pylori Oncoprotein CagA. Cancers (Basel) 2019; 11:cancers11081163. [PMID: 31412675 PMCID: PMC6721621 DOI: 10.3390/cancers11081163] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Revised: 07/25/2019] [Accepted: 08/08/2019] [Indexed: 02/07/2023] Open
Abstract
The gastric pathogen and carcinogen Helicobacter pylori(H. pylori) encodes a type IV secretion system for translocation of the effector protein CagA into host cells. Injected CagA becomes tyrosine-phosphorylated at the five amino acid residue Glutamate-Proline- Isoleucine-Tyrosine-Alanine (EPIYA)-sequence motifs. These phosphorylated EPIYA-sites represent recognition motifs for binding of multiple host factors, which then manipulate signaling pathways to trigger gastric disease. Thus, efficient detection of single phosphorylated EPIYA-motifs in CagA is required. Detection of phospho-CagA is primarily performed using commercial pan-phosphotyrosine antibodies. However, those antibodies were originally generated to recognize many phosphotyrosines in various mammalian proteins and are not optimized for use in bacteria. To address this important limitation, we synthesized 11-mer phospho- and non-phospho-peptides from EPIYA-motifs A, B, and C, and produced three phospho-specific and three non-phospho-specific rabbit polyclonal CagA antibodies. These antibodies specifically recognized the corresponding phosphorylated and non-phosphorylated EPIYA-motifs, while the EPIYA-C antibodies also recognized the related East-Asian EPIYA-D motif. Otherwise, no cross-reactivity of the antibodies among EPIYAs was observed. Western blotting demonstrated that each EPIYA-motif can be predominantly phosphorylated during H. pylori infection. This represents the first complete set of phospho-specific antibodies for an effector protein in bacteria, providing useful tools to gather information for the categorization of CagA phosphorylation, cancer signaling, and gastric disease progression.
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Affiliation(s)
- Suneesh Kumar Pachathundikandi
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, Staudtstraße 5, D-91058 Erlangen, Germany
| | - Andrés Julián Gutiérrez-Escobar
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, Staudtstraße 5, D-91058 Erlangen, Germany
| | - Nicole Tegtmeyer
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, Staudtstraße 5, D-91058 Erlangen, Germany.
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25
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Buß M, Tegtmeyer N, Schnieder J, Dong X, Li J, Springer TA, Backert S, Niemann HH. Specific high affinity interaction of Helicobacter pylori CagL with integrin α V β 6 promotes type IV secretion of CagA into human cells. FEBS J 2019; 286:3980-3997. [PMID: 31197920 DOI: 10.1111/febs.14962] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 04/12/2019] [Accepted: 06/10/2019] [Indexed: 12/21/2022]
Abstract
CagL is an essential pilus surface component of the virulence-associated type IV secretion system (T4SS) employed by Helicobacter pylori to translocate the oncogenic effector protein CagA into human gastric epithelial cells. CagL contains an RGD motif and integrin α5 β1 is widely accepted as its host cell receptor. Here, we show that CagL binds integrin αV β6 with substantially higher affinity and that this interaction is functionally important. Cell surface expression of αV β6 on various cell lines correlated perfectly with cell adhesion to immobilized CagL and with binding of soluble CagL to cells. We found no such correlation for α5 β1 . The purified αV β6 ectodomain bound CagL with high affinity. This interaction was highly specific, as the affinity of CagL for other RGD-binding integrins was two to three orders of magnitude weaker. Mutation of either conserved leucine in the CagL RGDLXXL motif, a motif that generally confers specificity for integrin αV β6 and αV β8 , lowered the affinity of CagL for αV β6 . Stable expression of αV β6 in αV β6 -negative but α5 β1 -expressing human cells promoted two hallmarks of the functional H. pylori T4SS, namely translocation of CagA into host cells and induction of interleukin-8 secretion by host cells. These findings suggest that integrin αV β6 , although not essential for T4SS function, represents an important host cell receptor for CagL.
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Affiliation(s)
- Maren Buß
- Structural Biochemistry, Department of Chemistry, Bielefeld University, Germany
| | - Nicole Tegtmeyer
- Division of Microbiology, Department of Biology, Friedrich-Alexander-University, Erlangen-Nuremberg, Germany
| | - Jennifer Schnieder
- Structural Biochemistry, Department of Chemistry, Bielefeld University, Germany
| | - Xianchi Dong
- Children's Hospital Boston, MA, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Jing Li
- Children's Hospital Boston, MA, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Timothy A Springer
- Children's Hospital Boston, MA, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Steffen Backert
- Division of Microbiology, Department of Biology, Friedrich-Alexander-University, Erlangen-Nuremberg, Germany
| | - Hartmut H Niemann
- Structural Biochemistry, Department of Chemistry, Bielefeld University, Germany
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26
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Schmidt AM, Escher U, Mousavi S, Tegtmeyer N, Boehm M, Backert S, Bereswill S, Heimesaat MM. Immunopathological properties of the Campylobacter jejuni flagellins and the adhesin CadF as assessed in a clinical murine infection model. Gut Pathog 2019; 11:24. [PMID: 31131028 PMCID: PMC6525468 DOI: 10.1186/s13099-019-0306-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Accepted: 05/10/2019] [Indexed: 12/11/2022] Open
Abstract
Background Campylobacter jejuni infections constitute serious threats to human health with increasing prevalences worldwide. Our knowledge regarding the molecular mechanisms underlying host–pathogen interactions is still limited. Our group has established a clinical C. jejuni infection model based on abiotic IL-10−/− mice mimicking key features of human campylobacteriosis. In order to further validate this model for unraveling pathogen-host interactions mounting in acute disease, we here surveyed the immunopathological features of the important C. jejuni virulence factors FlaA and FlaB and the major adhesin CadF (Campylobacter adhesin to fibronectin), which play a role in bacterial motility, protein secretion and adhesion, respectively. Methods and results Therefore, abiotic IL-10−/− mice were perorally infected with C. jejuni strain 81-176 (WT) or with its isogenic flaA/B (ΔflaA/B) or cadF (ΔcadF) deletion mutants. Cultural analyses revealed that WT and ΔcadF but not ΔflaA/B bacteria stably colonized the stomach, duodenum and ileum, whereas all three strains were present in the colon at comparably high loads on day 6 post-infection. Remarkably, despite high colonic colonization densities, murine infection with the ΔflaA/B strain did not result in overt campylobacteriosis, whereas mice infected with ΔcadF or WT were suffering from acute enterocolitis at day 6 post-infection. These symptoms coincided with pronounced pro-inflammatory immune responses, not only in the intestinal tract, but also in other organs such as the liver and kidneys and were accompanied with systemic inflammatory responses as indicated by increased serum MCP-1 concentrations following C. jejuni ΔcadF or WT, but not ΔflaA/B strain infection. Conclusion For the first time, our observations revealed that the C. jejuni flagellins A/B, but not adhesion mediated by CadF, are essential for inducing murine campylobacteriosis. Furthermore, the secondary abiotic IL-10−/− infection model has been proven suitable not only for detailed investigations of immunological aspects of campylobacteriosis, but also for differential analyses of the roles of distinct C. jejuni virulence factors in induction and progression of disease. Electronic supplementary material The online version of this article (10.1186/s13099-019-0306-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Anna-Maria Schmidt
- Department of Microbiology, Institute of Microbiology, Infectious Diseases and Immunology, Charité-University Medicine Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, CC5, Campus Benjamin Franklin, FEM, Garystr. 5, 14195 Berlin, Germany
| | - Ulrike Escher
- Department of Microbiology, Institute of Microbiology, Infectious Diseases and Immunology, Charité-University Medicine Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, CC5, Campus Benjamin Franklin, FEM, Garystr. 5, 14195 Berlin, Germany
| | - Soraya Mousavi
- Department of Microbiology, Institute of Microbiology, Infectious Diseases and Immunology, Charité-University Medicine Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, CC5, Campus Benjamin Franklin, FEM, Garystr. 5, 14195 Berlin, Germany
| | - Nicole Tegtmeyer
- 2Institute for Microbiology, Department of Biology, Friedrich Alexander University Erlangen/Nuremberg, Erlangen, Germany
| | - Manja Boehm
- 2Institute for Microbiology, Department of Biology, Friedrich Alexander University Erlangen/Nuremberg, Erlangen, Germany
| | - Steffen Backert
- 2Institute for Microbiology, Department of Biology, Friedrich Alexander University Erlangen/Nuremberg, Erlangen, Germany
| | - Stefan Bereswill
- Department of Microbiology, Institute of Microbiology, Infectious Diseases and Immunology, Charité-University Medicine Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, CC5, Campus Benjamin Franklin, FEM, Garystr. 5, 14195 Berlin, Germany
| | - Markus M Heimesaat
- Department of Microbiology, Institute of Microbiology, Infectious Diseases and Immunology, Charité-University Medicine Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, CC5, Campus Benjamin Franklin, FEM, Garystr. 5, 14195 Berlin, Germany
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27
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Harrer A, Bücker R, Boehm M, Zarzecka U, Tegtmeyer N, Sticht H, Schulzke JD, Backert S. Campylobacter jejuni enters gut epithelial cells and impairs intestinal barrier function through cleavage of occludin by serine protease HtrA. Gut Pathog 2019; 11:4. [PMID: 30805031 PMCID: PMC6373145 DOI: 10.1186/s13099-019-0283-z] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 02/01/2019] [Indexed: 01/17/2023] Open
Abstract
Campylobacter jejuni secretes HtrA (high temperature requirement protein A), a serine protease that is involved in virulence. Here, we investigated the interaction of HtrA with the host protein occludin, a tight junction strand component. Immunofluorescence studies demonstrated that infection of polarized intestinal Caco-2 cells with C. jejuni strain 81-176 resulted in a redistribution of occludin away from the tight junctions into the cytoplasm, an effect that was also observed in human biopsies during acute campylobacteriosis. Occludin knockout Caco-2 cells were generated by CRISPR/Cas9 technology. Inactivation of this gene affected the polarization of the cells in monolayers and transepithelial electrical resistance (TER) was reduced, compared to wild-type Caco-2 cells. Although tight junctions were still being formed, occludin deficiency resulted in a slight decrease of the tight junction plaque protein ZO-1, which was redistributed off the tight junction into the lateral plasma membrane. Adherence of C. jejuni to Caco-2 cell monolayers was similar between the occludin knockout compared to wild-type cells, but invasion was enhanced, indicating that deletion of occludin allowed larger numbers of bacteria to pass the tight junctions and to reach basal membranes to target the fibronectin receptor followed by cell entry. Finally, we discovered that purified C. jejuni HtrA cleaves recombinant occludin in vitro to release a 37 kDa carboxy-terminal fragment. The same cleavage fragment was observed in Western blots upon infection of polarized Caco-2 cells with wild-type C. jejuni, but not with isogenic ΔhtrA mutants. HtrA cleavage was mapped to the second extracellular loop of occludin, and a putative cleavage site was identified. In conclusion, HtrA functions as a secreted protease targeting the tight junctions, which enables the bacteria by cleaving occludin and subcellular redistribution of other tight junction proteins to transmigrate using a paracellular mechanism and subsequently invade epithelial cells.
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Affiliation(s)
- Aileen Harrer
- 1Division of Microbiology, Dept. of Biology, University of Erlangen-Nuremberg, Staudtstr. 5, 91058 Erlangen, Germany
| | - Roland Bücker
- 2Institut für Klinische Physiologie, Med. Klinik m.S. Gastroenterologie, Infektiologie und Rheumatologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Manja Boehm
- 1Division of Microbiology, Dept. of Biology, University of Erlangen-Nuremberg, Staudtstr. 5, 91058 Erlangen, Germany
| | - Urszula Zarzecka
- 1Division of Microbiology, Dept. of Biology, University of Erlangen-Nuremberg, Staudtstr. 5, 91058 Erlangen, Germany.,4Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, 80-308 Gdansk, Poland
| | - Nicole Tegtmeyer
- 1Division of Microbiology, Dept. of Biology, University of Erlangen-Nuremberg, Staudtstr. 5, 91058 Erlangen, Germany
| | - Heinrich Sticht
- 3Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Jörg D Schulzke
- 2Institut für Klinische Physiologie, Med. Klinik m.S. Gastroenterologie, Infektiologie und Rheumatologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Steffen Backert
- 1Division of Microbiology, Dept. of Biology, University of Erlangen-Nuremberg, Staudtstr. 5, 91058 Erlangen, Germany
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Tegtmeyer N, Harrer A, Schmitt V, Singer BB, Backert S. Expression of CEACAM1 or CEACAM5 in AZ-521 cells restores the type IV secretion deficiency for translocation of CagA byHelicobacter pylori. Cell Microbiol 2018; 21:e12965. [DOI: 10.1111/cmi.12965] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 10/04/2018] [Accepted: 10/08/2018] [Indexed: 02/06/2023]
Affiliation(s)
- Nicole Tegtmeyer
- Department of Biology, Division of Microbiology; Friedrich Alexander University Erlangen; Erlangen Germany
| | - Aileen Harrer
- Department of Biology, Division of Microbiology; Friedrich Alexander University Erlangen; Erlangen Germany
| | - Verena Schmitt
- Medical Faculty, Institute of Anatomy; University of Duisburg-Essen; Essen Germany
| | - Bernhard B. Singer
- Medical Faculty, Institute of Anatomy; University of Duisburg-Essen; Essen Germany
| | - Steffen Backert
- Department of Biology, Division of Microbiology; Friedrich Alexander University Erlangen; Erlangen Germany
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29
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Tegtmeyer N, Wessler S, Necchi V, Rohde M, Harrer A, Rau TT, Asche CI, Boehm M, Loessner H, Figueiredo C, Naumann M, Palmisano R, Solcia E, Ricci V, Backert S. Helicobacter pylori Employs a Unique Basolateral Type IV Secretion Mechanism for CagA Delivery. Cell Host Microbe 2018; 22:552-560.e5. [PMID: 29024645 DOI: 10.1016/j.chom.2017.09.005] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 07/26/2017] [Accepted: 09/08/2017] [Indexed: 01/16/2023]
Abstract
The Helicobacter pylori (Hp) type IV secretion system (T4SS) forms needle-like pili, whose binding to the integrin-β1 receptor results in injection of the CagA oncoprotein. However, the apical surface of epithelial cells is exposed to Hp, whereas integrins are basolateral receptors. Hence, the mechanism of CagA delivery into polarized gastric epithelial cells remains enigmatic. Here, we demonstrate that T4SS pilus formation during infection of polarized cells occurs predominantly at basolateral membranes, and not at apical sites. Hp accomplishes this by secreting another bacterial protein, the serine protease HtrA, which opens cell-to-cell junctions through cleaving epithelial junctional proteins including occludin, claudin-8, and E-cadherin. Using a genetic system expressing a peptide inhibitor, we demonstrate that HtrA activity is necessary for paracellular transmigration of Hp across polarized cell monolayers to reach basolateral membranes and inject CagA. The contribution of this unique signaling cascade to Hp pathogenesis is discussed.
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Affiliation(s)
- Nicole Tegtmeyer
- Department of Biology, Division of Microbiology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Silja Wessler
- Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | - Vittorio Necchi
- Pathologic Anatomy and Human Physiology Units and Centro Grandi Strumenti, University of Pavia and Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Manfred Rohde
- Helmholtz Centre for Infection Research, Microscopy Unit, Braunschweig, Germany
| | - Aileen Harrer
- Department of Biology, Division of Microbiology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Tilman T Rau
- Institute of Pathology, University of Erlangen-Nuremberg, Erlangen, Germany; Institute of Pathology, University of Bern, Bern, Switzerland
| | - Carmen Isabell Asche
- Department of Biology, Division of Microbiology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Manja Boehm
- Department of Biology, Division of Microbiology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Holger Loessner
- Paul Ehrlich Institute, Department of Microbiology, Langen, Germany
| | - Ceu Figueiredo
- University of Porto, i3S, IPATIMUP, Faculty of Medicine, Porto, Portugal
| | - Michael Naumann
- Otto von Guericke University, Institute of Experimental Internal Medicine, Magdeburg, Germany
| | - Ralf Palmisano
- Optical Imaging Centre, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Enrico Solcia
- Pathologic Anatomy and Human Physiology Units and Centro Grandi Strumenti, University of Pavia and Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Vittorio Ricci
- Pathologic Anatomy and Human Physiology Units and Centro Grandi Strumenti, University of Pavia and Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Steffen Backert
- Department of Biology, Division of Microbiology, University of Erlangen-Nuremberg, Erlangen, Germany.
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30
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Boehm M, Simson D, Escher U, Schmidt AM, Bereswill S, Tegtmeyer N, Backert S, Heimesaat MM. Function of Serine Protease HtrA in the Lifecycle of the Foodborne Pathogen Campylobacter jejuni. Eur J Microbiol Immunol (Bp) 2018; 8:70-77. [PMID: 30345086 PMCID: PMC6186014 DOI: 10.1556/1886.2018.00011] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 06/18/2018] [Indexed: 12/19/2022] Open
Abstract
Campylobacter jejuni is a major food-borne zoonotic pathogen, responsible for a large proportion of bacterial gastroenteritis cases, as well as Guillian-Barré and Miller-Fisher syndromes. During infection, tissue damage is mainly caused by bacteria invading epithelial cells and traversing the intestinal barrier. C. jejuni is able to enter the lamina propria and the bloodstream and may move into other organs, such as spleen, liver, or mesenteric lymph nodes. However, the involved molecular mechanisms are not fully understood. C. jejuni can transmigrate effectively across polarized intestinal epithelial cells mainly by the paracellular route using the serine protease high-temperature requirement A (HtrA). However, it appears that HtrA has a dual function, as it also acts as a chaperone, interacting with denatured or misfolded periplasmic proteins under stress conditions. Here, we review recent progress on the role of HtrA in C. jejuni pathogenesis. HtrA can be transported into the extracellular space and cleaves cell-to-cell junction factors, such as E-cadherin and probably others, disrupting the epithelial barrier and enabling paracellular transmigration of the bacteria. The secretion of HtrA is a newly discovered strategy also utilized by other pathogens. Thus, secreted HtrA proteases represent highly attractive targets for anti-bacterial treatment and may provide a suitable candidate for vaccine development.
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Affiliation(s)
- Manja Boehm
- Department of Biology, Institute for Microbiology, Friedrich Alexander University Erlangen/Nuremberg, Staudtstr. 5, D-91058 Erlangen, Germany
| | - Daniel Simson
- Department of Biology, Institute for Microbiology, Friedrich Alexander University Erlangen/Nuremberg, Staudtstr. 5, D-91058 Erlangen, Germany
| | - Ulrike Escher
- Department of Microbiology and Infection Immunology, Charité - University Medicine Berlin, Berlin, Germany
| | - Anna-Maria Schmidt
- Department of Microbiology and Infection Immunology, Charité - University Medicine Berlin, Berlin, Germany
| | - Stefan Bereswill
- Department of Microbiology and Infection Immunology, Charité - University Medicine Berlin, Berlin, Germany
| | - Nicole Tegtmeyer
- Department of Biology, Institute for Microbiology, Friedrich Alexander University Erlangen/Nuremberg, Staudtstr. 5, D-91058 Erlangen, Germany
| | - Steffen Backert
- Department of Biology, Institute for Microbiology, Friedrich Alexander University Erlangen/Nuremberg, Staudtstr. 5, D-91058 Erlangen, Germany
| | - Markus M Heimesaat
- Department of Microbiology and Infection Immunology, Charité - University Medicine Berlin, Berlin, Germany
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Moonens K, Hamway Y, Neddermann M, Reschke M, Tegtmeyer N, Kruse T, Kammerer R, Mejías-Luque R, Singer BB, Backert S, Gerhard M, Remaut H. Helicobacter pylori adhesin HopQ disrupts trans dimerization in human CEACAMs. EMBO J 2018; 37:embj.201798665. [PMID: 29858229 DOI: 10.15252/embj.201798665] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 05/08/2018] [Accepted: 05/15/2018] [Indexed: 01/24/2023] Open
Abstract
The human gastric pathogen Helicobacter pylori is a major causative agent of gastritis, peptic ulcer disease, and gastric cancer. As part of its adhesive lifestyle, the bacterium targets members of the carcinoembryonic antigen-related cell adhesion molecule (CEACAM) family by the conserved outer membrane adhesin HopQ. The HopQ-CEACAM1 interaction is associated with inflammatory responses and enables the intracellular delivery and phosphorylation of the CagA oncoprotein via a yet unknown mechanism. Here, we generated crystal structures of HopQ isotypes I and II bound to the N-terminal domain of human CEACAM1 (C1ND) and elucidated the structural basis of H. pylori specificity toward human CEACAM receptors. Both HopQ alleles target the β-strands G, F, and C of C1ND, which form the trans dimerization interface in homo- and heterophilic CEACAM interactions. Using SAXS, we show that the HopQ ectodomain is sufficient to induce C1ND monomerization and thus providing H. pylori a route to influence CEACAM-mediated cell adherence and signaling events.
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Affiliation(s)
- Kristof Moonens
- Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Brussels, Belgium.,Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Youssef Hamway
- Institute for Medical Microbiology, Immunology and Hygiene, Technische Universität München, Munich, Germany
| | - Matthias Neddermann
- Division of Microbiology, Department of Biology, Friedrich Alexander University Erlangen, Erlangen, Germany
| | - Marc Reschke
- Institute of Anatomy, Medical Faculty, University of Duisburg-Essen, Essen, Germany
| | - Nicole Tegtmeyer
- Division of Microbiology, Department of Biology, Friedrich Alexander University Erlangen, Erlangen, Germany
| | | | - Robert Kammerer
- Institute of Immunology, Friedrich-Loeffler Institut, Greifswald-Insel Riems, Germany
| | - Raquel Mejías-Luque
- Institute for Medical Microbiology, Immunology and Hygiene, Technische Universität München, Munich, Germany.,German Center for Infection Research, Partner Site Munich, Munich, Germany
| | - Bernhard B Singer
- Institute of Anatomy, Medical Faculty, University of Duisburg-Essen, Essen, Germany
| | - Steffen Backert
- Division of Microbiology, Department of Biology, Friedrich Alexander University Erlangen, Erlangen, Germany
| | - Markus Gerhard
- Institute for Medical Microbiology, Immunology and Hygiene, Technische Universität München, Munich, Germany.,German Center for Infection Research, Partner Site Munich, Munich, Germany
| | - Han Remaut
- Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Brussels, Belgium .,Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
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32
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Albrecht N, Tegtmeyer N, Sticht H, Skórko-Glonek J, Backert S. Amino-Terminal Processing of Helicobacter pylori Serine Protease HtrA: Role in Oligomerization and Activity Regulation. Front Microbiol 2018; 9:642. [PMID: 29713313 PMCID: PMC5911493 DOI: 10.3389/fmicb.2018.00642] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 03/19/2018] [Indexed: 12/17/2022] Open
Abstract
The HtrA family of serine proteases is found in most bacteria, and plays an essential role in the virulence of the gastric pathogen Helicobacter pylori. Secreted H. pylori HtrA (HtrA Hp ) cleaves various junctional proteins such as E-cadherin disrupting the epithelial barrier, which is crucial for bacterial transmigration across the polarized epithelium. Recent studies indicated the presence of two characteristic HtrA Hp forms of 55 and 52 kDa (termed p55 and p52, respectively), in worldwide strains. In addition, p55 and p52 were produced by recombinant HtrA Hp , indicating auto-cleavage. However, the cleavage sites and their functional importance are yet unclear. Here, we determined the amino-terminal ends of p55 and p52 by Edman sequencing. Two proteolytic cleavage sites were identified (H46/D47 and K50/D51). Remarkably, the cleavage site sequences are conserved in HtrA Hp from worldwide isolates, but not in other Gram-negative pathogens, suggesting a highly specific assignment in H. pylori. We analyzed the role of the amino-terminal cleavage sites on activity, secretion and function of HtrA Hp . Three-dimensional modeling suggested a trimeric structure and a role of amino-terminal processing in oligomerization and regulation of proteolytic activity of HtrA Hp . Furthermore, point and deletion mutants of these processing sites were generated in the recently reported Campylobacter jejuni ΔhtrA/htrAHp genetic complementation system and the minimal sequence requirements for processing were determined. Polarized Caco-2 epithelial cells were infected with these strains and analyzed by immunofluorescence microscopy. The results indicated that HtrA Hp processing strongly affected the ability of the protease to disrupt the E-cadherin-based cell-to-cell junctions. Casein zymography confirmed that the amino-terminal region is required for maintaining the proteolytic activity of HtrA Hp . Furthermore, we demonstrated that this cleavage influences the secretion of HtrA Hp in the extracellular space as an important prerequisite for its virulence activity. Taken together, our data demonstrate that amino-terminal cleavage of HtrA Hp is conserved in this pathogen and affects oligomerization and thus, secretion and regulatory activities, suggesting an important role in the pathogenesis of H. pylori.
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Affiliation(s)
- Nicole Albrecht
- Division of Microbiology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Nicole Tegtmeyer
- Division of Microbiology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Joanna Skórko-Glonek
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Steffen Backert
- Division of Microbiology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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Tegtmeyer N, Backert S. Helicobacter pylori infection of AZ-521 cells reveals a type IV secretion defect and VacA-independent CagA phosphorylation. Dis Model Mech 2017; 10:1539-1540. [PMID: 29259027 PMCID: PMC5769614 DOI: 10.1242/dmm.032813] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 10/31/2017] [Indexed: 01/11/2023] Open
Affiliation(s)
- Nicole Tegtmeyer
- Friedrich Alexander University Erlangen, Department of Biology, Division of Microbiology, Staudtstr. 5, D-91058 Erlangen, Germany
| | - Steffen Backert
- Friedrich Alexander University Erlangen, Department of Biology, Division of Microbiology, Staudtstr. 5, D-91058 Erlangen, Germany
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Harrer A, Boehm M, Backert S, Tegtmeyer N. Overexpression of serine protease HtrA enhances disruption of adherens junctions, paracellular transmigration and type IV secretion of CagA by Helicobacter pylori. Gut Pathog 2017; 9:40. [PMID: 28770008 PMCID: PMC5526239 DOI: 10.1186/s13099-017-0189-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Accepted: 07/11/2017] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND The serine protease HtrA is an important factor for regulating stress responses and protein quality control in bacteria. In recent studies, we have demonstrated that the gastric pathogen Helicobacter pylori can secrete HtrA into the extracellular environment, where it cleaves-off the ectodomain of the tumor suppressor and adherens junction protein E-cadherin on gastric epithelial cells. RESULTS E-cadherin cleavage opens cell-to-cell junctions, allowing paracellular transmigration of the bacteria across polarized monolayers of MKN-28 and Caco-2 epithelial cells. However, rapid research progress on HtrA function is mainly hampered by the lack of ΔhtrA knockout mutants, suggesting that htrA may represent an essential gene in H. pylori. To circumvent this major handicap and to investigate the role of HtrA further, we overexpressed HtrA by introducing a second functional htrA gene copy in the chromosome and studied various virulence properties of the bacteria. The resulting data demonstrate that overexpression of HtrA in H. pylori gives rise to elevated rates of HtrA secretion, cleavage of E-cadherin, bacterial transmigration and delivery of the type IV secretion system (T4SS) effector protein CagA into polarized epithelial cells, but did not affect IL-8 chemokine production or the secretion of vacuolating cytotoxin VacA and γ-glutamyl-transpeptidase GGT. CONCLUSIONS These data provide for the first time genetic evidence in H. pylori that HtrA is a novel major virulence factor controlling multiple pathogenic activities of this important microbe.
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Affiliation(s)
- Aileen Harrer
- Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, 91058 Erlangen, Germany
| | - Manja Boehm
- Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, 91058 Erlangen, Germany
| | - Steffen Backert
- Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, 91058 Erlangen, Germany
| | - Nicole Tegtmeyer
- Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, 91058 Erlangen, Germany
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35
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Tegtmeyer N, Neddermann M, Asche CI, Backert S. Subversion of host kinases: a key network in cellular signaling hijacked byHelicobacter pyloriCagA. Mol Microbiol 2017; 105:358-372. [DOI: 10.1111/mmi.13707] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2017] [Indexed: 12/16/2022]
Affiliation(s)
- Nicole Tegtmeyer
- Department of Biology, Division of Microbiology; Friedrich Alexander University Erlangen-Nuremberg; Staudtstr. 5 Erlangen D-91058 Germany
| | - Matthias Neddermann
- Department of Biology, Division of Microbiology; Friedrich Alexander University Erlangen-Nuremberg; Staudtstr. 5 Erlangen D-91058 Germany
| | - Carmen Isabell Asche
- Department of Biology, Division of Microbiology; Friedrich Alexander University Erlangen-Nuremberg; Staudtstr. 5 Erlangen D-91058 Germany
| | - Steffen Backert
- Department of Biology, Division of Microbiology; Friedrich Alexander University Erlangen-Nuremberg; Staudtstr. 5 Erlangen D-91058 Germany
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36
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Backert S, Tegtmeyer N. Type IV Secretion and Signal Transduction of Helicobacter pylori CagA through Interactions with Host Cell Receptors. Toxins (Basel) 2017; 9:E115. [PMID: 28338646 PMCID: PMC5408189 DOI: 10.3390/toxins9040115] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Revised: 03/20/2017] [Accepted: 03/22/2017] [Indexed: 02/06/2023] Open
Abstract
Helicobacter pylori is a highly successful human bacterium, which is exceptionally equipped to persistently inhabit the human stomach. Colonization by this pathogen is associated with gastric disorders ranging from chronic gastritis and peptic ulcers to cancer. Highly virulent H. pylori strains express the well-established adhesins BabA/B, SabA, AlpA/B, OipA, and HopQ, and a type IV secretion system (T4SS) encoded by the cag pathogenicity island (PAI). The adhesins ascertain intimate bacterial contact to gastric epithelial cells, while the T4SS represents an extracellular pilus-like structure for the translocation of the effector protein CagA. Numerous T4SS components including CagI, CagL, CagY, and CagA have been shown to target the integrin-β₁ receptor followed by translocation of CagA across the host cell membrane. The interaction of CagA with membrane-anchored phosphatidylserine and CagA-containing outer membrane vesicles may also play a role in the delivery process. Translocated CagA undergoes tyrosine phosphorylation in C-terminal EPIYA-repeat motifs by oncogenic Src and Abl kinases. CagA then interacts with an array of host signaling proteins followed by their activation or inactivation in phosphorylation-dependent and phosphorylation-independent fashions. We now count about 25 host cell binding partners of intracellular CagA, which represent the highest quantity of all currently known virulence-associated effector proteins in the microbial world. Here we review the research progress in characterizing interactions of CagA with multiple host cell receptors in the gastric epithelium, including integrin-β₁, EGFR, c-Met, CD44, E-cadherin, and gp130. The contribution of these interactions to H. pylori colonization, signal transduction, and gastric pathogenesis is discussed.
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Affiliation(s)
- Steffen Backert
- Division of Microbiology, Department of Biology, Friedrich Alexander University Erlangen-Nuremberg, Staudtstr. 5, D-91058 Erlangen, Germany.
| | - Nicole Tegtmeyer
- Division of Microbiology, Department of Biology, Friedrich Alexander University Erlangen-Nuremberg, Staudtstr. 5, D-91058 Erlangen, Germany.
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Javaheri A, Kruse T, Moonens K, Mejías-Luque R, Debraekeleer A, Asche CI, Tegtmeyer N, Kalali B, Bach NC, Sieber SA, Hill DJ, Königer V, Hauck CR, Moskalenko R, Haas R, Busch DH, Klaile E, Slevogt H, Schmidt A, Backert S, Remaut H, Singer BB, Gerhard M. Erratum: Helicobacter pylori adhesin HopQ engages in a virulence-enhancing interaction with human CEACAMs. Nat Microbiol 2016; 2:16243. [PMID: 27819267 DOI: 10.1038/nmicrobiol.2016.243] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Lind J, Backert S, Hoffmann R, Eichler J, Yamaoka Y, Perez-Perez GI, Torres J, Sticht H, Tegtmeyer N. Systematic analysis of phosphotyrosine antibodies recognizing single phosphorylated EPIYA-motifs in CagA of East Asian-type Helicobacter pylori strains. BMC Microbiol 2016; 16:201. [PMID: 27590005 PMCID: PMC5009636 DOI: 10.1186/s12866-016-0820-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 05/19/2016] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Highly virulent strains of the gastric pathogen Helicobacter pylori encode a type IV secretion system (T4SS) that delivers the effector protein CagA into gastric epithelial cells. Translocated CagA undergoes tyrosine phosphorylation by members of the oncogenic c-Src and c-Abl host kinases at EPIYA-sequence motifs A, B and D in East Asian-type strains. These phosphorylated EPIYA-motifs serve as recognition sites for various SH2-domains containing human proteins, mediating interactions of CagA with host signaling factors to manipulate signal transduction pathways. Recognition of phospho-CagA is mainly based on the use of commercial pan-phosphotyrosine antibodies that were originally designed to detect phosphotyrosines in mammalian proteins. Specific anti-phospho-EPIYA antibodies for each of the three sites in CagA are not forthcoming. RESULTS This study was designed to systematically analyze the detection preferences of each phosphorylated East Asian CagA EPIYA-motif by pan-phosphotyrosine antibodies and to determine a minimal recognition sequence. We synthesized phospho- and non-phosphopeptides derived from each predominant EPIYA-site, and determined the recognition patterns by seven different pan-phosphotyrosine antibodies using Western blotting, and also investigated representative East Asian H. pylori isolates during infection. The results indicate that a total of only 9-11 amino acids containing the phosphorylated East Asian EPIYA-types are required and sufficient to detect the phosphopeptides with high specificity. However, the sequence recognition by the different antibodies was found to bear high variability. From the seven antibodies used, only four recognized all three phosphorylated EPIYA-motifs A, B and D similarly well. Two of the phosphotyrosine antibodies preferentially bound primarily to the phosphorylated motif A and D, while the seventh antibody failed to react with any of the phosphorylated EPIYA-motifs. Control experiments confirmed that none of the antibodies reacted with non-phospho-CagA peptides and in accordance were able to recognize phosphotyrosine proteins in human cells. CONCLUSIONS The results of this study disclose the various binding preferences of commercial anti-phosphotyrosine antibodies for phospho-EPIYA-motifs, and are valuable in the application for further characterization of CagA phosphorylation events during infection with H. pylori and risk prediction for gastric disease development.
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Affiliation(s)
- Judith Lind
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, Staudtstr. 5, D-91058, Erlangen, Germany
| | - Steffen Backert
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, Staudtstr. 5, D-91058, Erlangen, Germany
| | - Rebecca Hoffmann
- Department of Chemistry and Pharmacy, Friedrich Alexander University Erlangen-Nuremberg, Schuhstraße 19, D-91052, Erlangen, Germany
| | - Jutta Eichler
- Department of Chemistry and Pharmacy, Friedrich Alexander University Erlangen-Nuremberg, Schuhstraße 19, D-91052, Erlangen, Germany
| | - Yoshio Yamaoka
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Yufu, Japan
| | - Guillermo I Perez-Perez
- Department of Medicine and Microbiology, New York University, Langone Medical Centre, New York, USA
| | - Javier Torres
- Unidad de Investigación en Enfermedades Infecciosas, Hospital de Pediatría del Instituto Mexicano del Seguro Social, Mexico City, México
| | - Heinrich Sticht
- Bioinformatics, Institute for Biochemistry, Friedrich Alexander University Erlangen-Nuremberg, Fahrstrasse 17, D-91054, Erlangen, Germany
| | - Nicole Tegtmeyer
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, Staudtstr. 5, D-91058, Erlangen, Germany.
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39
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Backert S, Tegtmeyer N, Fischer W. Composition, structure and function of the Helicobacter pylori cag pathogenicity island encoded type IV secretion system. Future Microbiol 2016; 10:955-65. [PMID: 26059619 DOI: 10.2217/fmb.15.32] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Many Gram-negative pathogens harbor type IV secretion systems (T4SS) that translocate bacterial virulence factors into host cells to hijack cellular processes. The pathology of the gastric pathogen Helicobacter pylori strongly depends on a T4SS encoded by the cag pathogenicity island. This T4SS forms a needle-like pilus, and its assembly is accomplished by multiple protein-protein interactions and various pilus-associated factors that bind to integrins followed by delivery of the CagA oncoprotein into gastric epithelial cells. Recent studies revealed the crystal structures of six T4SS proteins and pilus formation is modulated by iron and zinc availability. All these T4SS interactions are crucial for deregulating host signaling events and disease progression. New developments in T4SS functions and their importance for pathogenesis are discussed.
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Affiliation(s)
- Steffen Backert
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, Staudtstr. 5, D-91058 Erlangen, Germany
| | - Nicole Tegtmeyer
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, Staudtstr. 5, D-91058 Erlangen, Germany
| | - Wolfgang Fischer
- Max von Pettenkofer-Institute for Hygiene & Medical Microbiology, Ludwig Maximilians-University, D-80336 Munich, Germany
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40
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Tegtmeyer N, Moodley Y, Yamaoka Y, Pernitzsch SR, Schmidt V, Traverso FR, Schmidt TP, Rad R, Yeoh KG, Bow H, Torres J, Gerhard M, Schneider G, Wessler S, Backert S. Characterisation of worldwide Helicobacter pylori strains reveals genetic conservation and essentiality of serine protease HtrA. Mol Microbiol 2015; 99:925-44. [PMID: 26568477 PMCID: PMC4832355 DOI: 10.1111/mmi.13276] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2015] [Indexed: 12/11/2022]
Abstract
HtrA proteases and chaperones exhibit important roles in periplasmic protein quality control and stress responses. The genetic inactivation of htrA has been described for many bacterial pathogens. However, in some cases such as the gastric pathogen Helicobacter pylori, HtrA is secreted where it cleaves the tumour‐suppressor E‐cadherin interfering with gastric disease development, but the generation of htrA mutants is still lacking. Here, we show that the htrA gene locus is highly conserved in worldwide strains. HtrA presence was confirmed in 992 H. pylori isolates in gastric biopsy material from infected patients. Differential RNA‐sequencing (dRNA‐seq) indicated that htrA is encoded in an operon with two subsequent genes, HP1020 and HP1021. Genetic mutagenesis and complementation studies revealed that HP1020 and HP1021, but not htrA, can be mutated. In addition, we demonstrate that suppression of HtrA proteolytic activity with a newly developed inhibitor is sufficient to effectively kill H. pylori, but not other bacteria. We show that Helicobacter
htrA is an essential bifunctional gene with crucial intracellular and extracellular functions. Thus, we describe here the first microbe in which htrA is an indispensable gene, a situation unique in the bacterial kingdom. HtrA can therefore be considered a promising new target for anti‐bacterial therapy.
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Affiliation(s)
- Nicole Tegtmeyer
- Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, D-91058, Erlangen, Germany.,Institut für Medizinische Mikrobiologie, Otto-von-Guericke Universität Magdeburg, Leipziger Str. 44, D-39120, Magdeburg, Germany
| | - Yoshan Moodley
- Department of Zoology, University of Venda, Private Bag X5050, Thohoyandou, 0950, South Africa.,Konrad-Lorenz-Institut für Vergleichende Verhaltensforschung, Department für Integrative Biologie und Evolution, Veterinärmedizinische Universität Wien, Savoyenstr. 1a, A-1160, Wien, Austria
| | - Yoshio Yamaoka
- Michael E. DeBakey Veterans Affairs Medical Center and Baylor College of Medicine, Dept. Medicine-Gastroenterology, Houston, TX, USA.,Oita University Faculty of Medicine, Dept. Environmental and Preventive Medicine, Yufu, Japan
| | - Sandy Ramona Pernitzsch
- Research Center for Infectious Diseases (ZINF), University of Würzburg, Josef-Schneider-Str. 2/Bau D15, D-97080, Würzburg, Germany
| | - Vanessa Schmidt
- Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, D-91058, Erlangen, Germany
| | - Francisco Rivas Traverso
- Institut für Medizinische Mikrobiologie, Otto-von-Guericke Universität Magdeburg, Leipziger Str. 44, D-39120, Magdeburg, Germany
| | - Thomas P Schmidt
- Department of Molecular Biology, Division of Microbiology, Paris-Lodron University of Salzburg, Billroth Str. 11, A-5020, Salzburg, Austria
| | - Roland Rad
- II Medical Department, Klinikum Rechts der Isar, Technical University Munich, Munich, Germany.,German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Khay Guan Yeoh
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Ho Bow
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Javier Torres
- Unidad de Investigacion en Enfermedades Infecciosas, UMAE Pediatria, IMSS, Mexico City, Mexico
| | - Markus Gerhard
- Institut für Medizinische Mikrobiologie, Immunologie und Hygiene, Technische Universität München, Munich, 81675, Germany
| | - Gisbert Schneider
- ETH Zürich, Institut für Pharmazeutische Wissenschaften, Vladimir-Prelog-Weg 4, CH-8093, Zürich, Switzerland
| | - Silja Wessler
- Department of Molecular Biology, Division of Microbiology, Paris-Lodron University of Salzburg, Billroth Str. 11, A-5020, Salzburg, Austria
| | - Steffen Backert
- Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, D-91058, Erlangen, Germany.,Institut für Medizinische Mikrobiologie, Otto-von-Guericke Universität Magdeburg, Leipziger Str. 44, D-39120, Magdeburg, Germany
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Hartung ML, Gruber DC, Koch KN, Grüter L, Rehrauer H, Tegtmeyer N, Backert S, Müller A. H. pylori-Induced DNA Strand Breaks Are Introduced by Nucleotide Excision Repair Endonucleases and Promote NF-κB Target Gene Expression. Cell Rep 2015; 13:70-79. [PMID: 26411687 DOI: 10.1016/j.celrep.2015.08.074] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 08/07/2015] [Accepted: 08/26/2015] [Indexed: 12/30/2022] Open
Abstract
The human bacterial pathogen Helicobacter pylori exhibits genotoxic properties that promote gastric carcinogenesis. H. pylori introduces DNA double strand breaks (DSBs) in epithelial cells that trigger host cell DNA repair efforts. Here, we show that H. pylori-induced DSBs are repaired via error-prone, potentially mutagenic non-homologous end-joining. A genome-wide screen for factors contributing to DSB induction revealed a critical role for the H. pylori type IV secretion system (T4SS). Inhibition of transcription, as well as NF-κB/RelA-specific RNAi, abrogates DSB formation. DSB induction further requires β1-integrin signaling. DSBs are introduced by the nucleotide excision repair endonucleases XPF and XPG, which, together with RelA, are recruited to chromatin in a highly coordinated, T4SS-dependent manner. Interestingly, XPF/XPG-mediated DNA DSBs promote NF-κB target gene transactivation and host cell survival. In summary, H. pylori induces XPF/XPG-mediated DNA damage through activation of the T4SS/β1-integrin signaling axis, which promotes NF-κB target gene expression and host cell survival.
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Affiliation(s)
- Mara L Hartung
- Institute of Molecular Cancer Research, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Dorothea C Gruber
- Institute of Molecular Cancer Research, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Katrin N Koch
- Institute of Molecular Cancer Research, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Livia Grüter
- Institute of Molecular Cancer Research, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Hubert Rehrauer
- Functional Genomics Center Zurich, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Nicole Tegtmeyer
- Department of Biology, Friedrich Alexander University Erlangen-Nuremberg, Staudtstrasse 5, 91085 Erlangen, Germany
| | - Steffen Backert
- Department of Biology, Friedrich Alexander University Erlangen-Nuremberg, Staudtstrasse 5, 91085 Erlangen, Germany
| | - Anne Müller
- Institute of Molecular Cancer Research, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
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Boehm M, Lind J, Backert S, Tegtmeyer N. Campylobacter jejuni serine protease HtrA plays an important role in heat tolerance, oxygen resistance, host cell adhesion, invasion, and transmigration. Eur J Microbiol Immunol (Bp) 2015; 5:68-80. [PMID: 25883795 DOI: 10.1556/eujmi-d-15-00003] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 01/13/2015] [Indexed: 12/29/2022] Open
Abstract
Campylobacter jejuni is an important pathogen of foodborne illness. Transmigration across the intestinal epithelial barrier and invasion are considered as primary reasons for tissue damage triggered by C. jejuni. Using knockout mutants, it was shown that the serine protease HtrA may be important for stress tolerance and physiology of C. jejuni. HtrA is also secreted in the extra-cellular environment, where it can cleave junctional host cell proteins such as E-cadherin. Aim of the present study was to establish a genetic complementation system in two C. jejuni strains in order to introduce the wild-type htrA gene in trans, test known htrA phenotypes, and provide the basis to perform further mutagenesis. We confirm that reexpression of the htrA wild-type gene in ΔhtrA mutants restored the following phenotypes: 1) C. jejuni growth at high temperature (44 °C), 2) growth under high oxygen stress conditions, 3) expression of proteolytically active HtrA oligomers, 4) secretion of HtrA into the supernatant, 5) cell attachment and invasion, and 6) transmigration across polarized epithelial cells. These results establish a genetic complementation system for htrA in C. jejuni, exclude polar effects in the ΔhtrA mutants, confirm important HtrA properties, and permit the discovery and dissection of new functions.
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Affiliation(s)
- Manja Boehm
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen/Nuremberg Staudtstr. 5, D-91058 Erlangen Germany
| | - Judith Lind
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen/Nuremberg Staudtstr. 5, D-91058 Erlangen Germany
| | - Steffen Backert
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen/Nuremberg Staudtstr. 5, D-91058 Erlangen Germany
| | - Nicole Tegtmeyer
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen/Nuremberg Staudtstr. 5, D-91058 Erlangen Germany
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Tenguria S, Ansari SA, Khan N, Ranjan A, Devi S, Tegtmeyer N, Lind J, Backert S, Ahmed N. Helicobacter pylori cell translocating kinase (CtkA/JHP0940) is pro-apoptotic in mouse macrophages and acts as auto-phosphorylating tyrosine kinase. Int J Med Microbiol 2014; 304:1066-76. [PMID: 25172221 DOI: 10.1016/j.ijmm.2014.07.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 06/26/2014] [Accepted: 07/28/2014] [Indexed: 12/16/2022] Open
Abstract
The Helicobacter pylori gene JHP0940 has been shown to encode a serine/threonine kinase which can induce cytokines in gastric epithelial cells relevant to chronic gastric inflammation. Here we demonstrate that JHP0940 can be secreted by the bacteria, triggers apoptosis in cultured mouse macrophages and acts as an auto-phosphorylating tyrosine kinase. Recombinant JHP0940 protein was found to decrease the viability of RAW264.7 cells (a mouse macrophage cell line) up to 55% within 24h of co-incubation. The decreased cellular viability was due to apoptosis, which was confirmed by TUNEL assay and Fas expression analysis by flow-cytometry. Further, we found that caspase-1 and IL-1beta were activated upon treatment with JHP0940. These results point towards possible action through the host inflammasome. Our in vitro studies using tyrosine kinase assays further demonstrated that JHP0940 acts as auto-phosphorylating tyrosine kinase and induces pro-inflammatory cytokines in RAW264.7 cells. Upon exposure with JHP0940, these cells secreted IL-1beta, TNF-alpha and IL-6, in a dose- and time-dependent manner, as detected by ELISA and transcript profiling by q-RT-PCR. The pro-inflammatory, pro-apoptotic and other regulatory responses triggered by JHP0940 lead to the assumption of its possible role in inducing chronic inflammation for enhanced bacterial persistence and escape from host innate immune responses by apoptosis of macrophages.
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Affiliation(s)
- Shivendra Tenguria
- Department of Biotechnology and Bioinformatics, University of Hyderabad, Hyderabad 500046, India
| | - Suhail A Ansari
- Department of Biotechnology and Bioinformatics, University of Hyderabad, Hyderabad 500046, India
| | - Nooruddin Khan
- Department of Biotechnology and Bioinformatics, University of Hyderabad, Hyderabad 500046, India
| | - Amit Ranjan
- Department of Biotechnology and Bioinformatics, University of Hyderabad, Hyderabad 500046, India
| | - Savita Devi
- Department of Biotechnology and Bioinformatics, University of Hyderabad, Hyderabad 500046, India
| | - Nicole Tegtmeyer
- Division of Microbiology, Department of Biology, Friedrich Alexander University Nuremberg, D-91058 Erlangen, Germany
| | - Judith Lind
- Division of Microbiology, Department of Biology, Friedrich Alexander University Nuremberg, D-91058 Erlangen, Germany
| | - Steffen Backert
- Division of Microbiology, Department of Biology, Friedrich Alexander University Nuremberg, D-91058 Erlangen, Germany
| | - Niyaz Ahmed
- Department of Biotechnology and Bioinformatics, University of Hyderabad, Hyderabad 500046, India.
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Heimesaat MM, Alutis M, Grundmann U, Fischer A, Tegtmeyer N, Böhm M, Kühl AA, Göbel UB, Backert S, Bereswill S. The role of serine protease HtrA in acute ulcerative enterocolitis and extra-intestinal immune responses during Campylobacter jejuni infection of gnotobiotic IL-10 deficient mice. Front Cell Infect Microbiol 2014; 4:77. [PMID: 24959425 PMCID: PMC4050650 DOI: 10.3389/fcimb.2014.00077] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 05/22/2014] [Indexed: 12/24/2022] Open
Abstract
Campylobacter jejuni infections have a high prevalence worldwide and represent a significant socioeconomic burden. C. jejuni can cross the intestinal epithelial barrier as visualized in biopsies derived from human patients and animal models, however, the underlying molecular mechanisms and associated immunopathology are still not well understood. We have recently shown that the secreted serine protease HtrA (high temperature requirement A) plays a key role in C. jejuni cellular invasion and transmigration across polarized epithelial cells in vitro. In the present in vivo study we investigated the role of HtrA during C. jejuni infection of mice. We used the gnotobiotic IL-10−/− mouse model to study campylobacteriosis following peroral infection with the C. jejuni wild-type (WT) strain NCTC11168 and the isogenic, non-polar NCTC11168ΔhtrA deletion mutant. Six days post infection (p.i.) with either strain mice harbored comparable intestinal C. jejuni loads, whereas ulcerative enterocolitis was less pronounced in mice infected with the ΔhtrA mutant strain. Moreover, ΔhtrA mutant infected mice displayed lower apoptotic cell numbers in the large intestinal mucosa, less colonic accumulation of neutrophils, macrophages and monocytes, lower large intestinal nitric oxide, IFN-γ, and IL-6 as well as lower TNF-α and IL-6 serum concentrations as compared to WT strain infected mice at day 6 p.i. Notably, immunopathological responses were not restricted to the intestinal tract given that liver and kidneys exhibited mild histopathological changes 6 days p.i. with either C. jejuni strain. We also found that hepatic and renal nitric oxide levels or renal TNF-α concentrations were lower in the ΔhtrA mutant as compared to WT strain infected mice. In conclusion, we show here that the C. jejuni HtrA protein plays a pivotal role in inducing host cell apoptosis and immunopathology during murine campylobacteriosis in the gut in vivo.
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Affiliation(s)
- Markus M Heimesaat
- Department of Microbiology and Hygiene, Charité - University Medicine Berlin Berlin, Germany
| | - Marie Alutis
- Department of Microbiology and Hygiene, Charité - University Medicine Berlin Berlin, Germany
| | - Ursula Grundmann
- Department of Microbiology and Hygiene, Charité - University Medicine Berlin Berlin, Germany
| | - André Fischer
- Department of Microbiology and Hygiene, Charité - University Medicine Berlin Berlin, Germany
| | - Nicole Tegtmeyer
- Division of Microbiology, Department of Biology, Friedrich Alexander University Erlangen/Nuremberg Erlangen, Germany
| | - Manja Böhm
- Division of Microbiology, Department of Biology, Friedrich Alexander University Erlangen/Nuremberg Erlangen, Germany
| | - Anja A Kühl
- Department of Medicine I for Gastroenterology, Infectious Disease and Rheumatology/Research Center ImmunoSciences, Charité - University Medicine Berlin Berlin, Germany
| | - Ulf B Göbel
- Department of Microbiology and Hygiene, Charité - University Medicine Berlin Berlin, Germany
| | - Steffen Backert
- Division of Microbiology, Department of Biology, Friedrich Alexander University Erlangen/Nuremberg Erlangen, Germany
| | - Stefan Bereswill
- Department of Microbiology and Hygiene, Charité - University Medicine Berlin Berlin, Germany
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Tegtmeyer N, Lind J, Schmid B, Backert S. Helicobacter pylori CagL Y58/E59 mutation turns-off type IV secretion-dependent delivery of CagA into host cells. PLoS One 2014; 9:e97782. [PMID: 24893039 PMCID: PMC4043526 DOI: 10.1371/journal.pone.0097782] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 04/23/2014] [Indexed: 12/13/2022] Open
Abstract
The type IV secretion system (T4SS) is a major virulence determinant of the gastric pathogen Helicobacter pylori. The CagL protein is a specialized adhesin of the corresponding T4SS pilus, which establishes initial contact with the integrin β1 receptor on host target cells. Recent studies proposed that Y58 and E59 amino acid polymorphisms in CagL increase the virulence of H. pylori strains by enhanced translocation and phosphorylation of the CagA effector protein. These polymorphisms were therefore correlated with an increased risk of gastric cancer development. Here we show that the Y58/E59 motif, which is located in a loop connecting two α-helices, and corresponding polymorphisms could influence the function of CagL. However, expression of isogenic CagL Y58/E59 variants in H. pylori strain 26695 significantly blocked the translocation and phosphorylation of CagA as compared to complemented wild-type CagL. These results suggest that the function of the T4SS for delivery of CagA is turned-off by the Y58/E59 mutation in CagL. This activity appears to be similar to the one recently described for another T4SS pilus protein, CagY, which is also sufficient to cause gain or loss of T4SS function. These data support the hypothesis that certain mutations in CagL or recombination events in CagY may serve as a sort of molecular switch or perhaps rheostat in the T4SS, which could alter the function of the pilus and "tunes" injection of CagA and host pro-inflammatory responses, respectively.
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Affiliation(s)
- Nicole Tegtmeyer
- Friedrich Alexander University Erlangen, Department of Biology, Division of Microbiology, Erlangen, Germany
| | - Judith Lind
- Friedrich Alexander University Erlangen, Department of Biology, Division of Microbiology, Erlangen, Germany
| | - Benedikt Schmid
- Friedrich Alexander University Erlangen, Department of Biology, Division of Biotechnique, Erlangen, Germany
| | - Steffen Backert
- Friedrich Alexander University Erlangen, Department of Biology, Division of Microbiology, Erlangen, Germany
- * E-mail:
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Heimesaat MM, Fischer A, Alutis M, Grundmann U, Boehm M, Tegtmeyer N, Göbel UB, Kühl AA, Bereswill S, Backert S. The impact of serine protease HtrA in apoptosis, intestinal immune responses and extra-intestinal histopathology during Campylobacter jejuni infection of infant mice. Gut Pathog 2014; 6:16. [PMID: 24883112 PMCID: PMC4040118 DOI: 10.1186/1757-4749-6-16] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Accepted: 05/19/2014] [Indexed: 12/19/2022] Open
Abstract
Background Campylobacter jejuni has emerged as a leading cause of bacterial enterocolitis. The serine protease HtrA has been shown to be a pivotal, novel C. jejuni virulence factor involved in cell invasion and transmigration across polarised epithelial cells in vitro. However, the functional relevance of the htrA gene for the interaction of C. jejuni with the host immune system in the infant mouse infection model has not been investigated so far. Results Here we studied the role of C. jejuni htrA during infection of 3-weeks-old infant mice. Immediately after weaning, conventional wild-type mice were perorally infected with the NCTC11168∆htrA mutant (∆htrA) or the parental wild-type strain. Approximately one third of infected infant mice suffered from bloody diarrhea until day 7 post infection (p.i.), whereas colonic histopathological changes were rather moderate but comparable between the two strains. Interestingly, parental, but not ∆htrA mutant infected mice, displayed a multifold increase of apoptotic cells in the colonic mucosa at day 7 p.i., which was paralleled by higher colonic levels of pro-inflammatory cytokines such as TNF-α and IFN-γ and the matrix-degrading enzyme matrixmetalloproteinase-2 (MMP-2). Furthermore, higher numbers of proliferating cells could be observed in the colon of ∆htrA infected mice as compared to the parental wild-type strain. Remarkably, as early as 7 days p.i. infant mice also exhibited inflammatory changes in extra-intestinal compartments such as liver, kidneys and lungs, which were less distinct in kidneys and lungs following ∆htrA versus parental strain infection. However, live C. jejuni bacteria could not be found in these organs, suggesting the induction of systemic effects during intestinal infection. Conclusion Upon C. jejuni ∆htrA strain infection of infant mice, intestinal and extra-intestinal pro-inflammatory immune responses were ameliorated in the infant mouse model system. Future studies will shed further light onto the molecular mechanisms of host-pathogen interactions.
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Affiliation(s)
- Markus M Heimesaat
- Department of Microbiology and Hygiene, Charité - University Medicine Berlin, Campus Benjamin Franklin, Hindenburgdamm 27, D-12203 Berlin, Germany
| | - André Fischer
- Department of Microbiology and Hygiene, Charité - University Medicine Berlin, Campus Benjamin Franklin, Hindenburgdamm 27, D-12203 Berlin, Germany
| | - Marie Alutis
- Department of Microbiology and Hygiene, Charité - University Medicine Berlin, Campus Benjamin Franklin, Hindenburgdamm 27, D-12203 Berlin, Germany
| | - Ursula Grundmann
- Department of Microbiology and Hygiene, Charité - University Medicine Berlin, Campus Benjamin Franklin, Hindenburgdamm 27, D-12203 Berlin, Germany
| | - Manja Boehm
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen, Nuremberg, Germany
| | - Nicole Tegtmeyer
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen, Nuremberg, Germany
| | - Ulf B Göbel
- Department of Microbiology and Hygiene, Charité - University Medicine Berlin, Campus Benjamin Franklin, Hindenburgdamm 27, D-12203 Berlin, Germany
| | - Anja A Kühl
- Department of Medicine I for Gastroenterology, Infectious Disease and Rheumatology / Research Center ImmunoSciences (RCIS), Charité - University Medicine Berlin, Berlin, Germany
| | - Stefan Bereswill
- Department of Microbiology and Hygiene, Charité - University Medicine Berlin, Campus Benjamin Franklin, Hindenburgdamm 27, D-12203 Berlin, Germany
| | - Steffen Backert
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen, Nuremberg, Germany
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Lind J, Backert S, Pfleiderer K, Berg DE, Yamaoka Y, Sticht H, Tegtmeyer N. Systematic analysis of phosphotyrosine antibodies recognizing single phosphorylated EPIYA-motifs in CagA of Western-type Helicobacter pylori strains. PLoS One 2014; 9:e96488. [PMID: 24800748 PMCID: PMC4011759 DOI: 10.1371/journal.pone.0096488] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 04/09/2014] [Indexed: 12/14/2022] Open
Abstract
The clinical outcome of Helicobacter pylori infections is determined by multiple host-pathogen interactions that may develop to chronic gastritis, and sometimes peptic ulcers or gastric cancer. Highly virulent strains encode a type IV secretion system (T4SS) that delivers the effector protein CagA into gastric epithelial cells. Translocated CagA undergoes tyrosine phosphorylation at EPIYA-sequence motifs, called A, B and C in Western-type strains, by members of the oncogenic Src and Abl host kinases. Phosphorylated EPIYA-motifs mediate interactions of CagA with host signaling factors--in particular various SH2-domain containing human proteins--thereby hijacking multiple downstream signaling cascades. Observations of tyrosine-phosphorylated CagA are mainly based on the use of commercial phosphotyrosine antibodies, which originally were selected to detect phosphotyrosines in mammalian proteins. Systematic studies of phosphorylated EPIYA-motif detection by the different antibodies would be very useful, but are not yet available. To address this issue, we synthesized phospho- and non-phosphopeptides representing each predominant Western CagA EPIYA-motif, and determined the recognition patterns of seven different phosphotyrosine antibodies in Western blots, and also performed infection studies with diverse representative Western H. pylori strains. Our results show that a total of 9-11 amino acids containing the phosphorylated EPIYA-motifs are necessary and sufficient for specific detection by these antibodies, but revealed great variability in sequence recognition. Three of the antibodies recognized phosphorylated EPIYA-motifs A, B and C similarly well; whereas preferential binding to phosphorylated motif A and motifs A and C was found with two and one antibodies, respectively, and the seventh anti-phosphotyrosine antibody did not recognize any phosphorylated EPIYA-motif. Controls showed that none of the antibodies recognized the corresponding non-phospho CagA peptides, and that all of them recognized phosphotyrosines in mammalian proteins. These data are valuable in judicious application of commercial anti-phosphotyrosine antibodies and in characterization of CagA phosphorylation during infection and disease development.
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Affiliation(s)
- Judith Lind
- Friedrich Alexander University Erlangen-Nuremberg, Department of Biology, Division of Microbiology, Erlangen, Germany
| | - Steffen Backert
- Friedrich Alexander University Erlangen-Nuremberg, Department of Biology, Division of Microbiology, Erlangen, Germany
| | - Klaus Pfleiderer
- Friedrich Alexander University Erlangen-Nuremberg, Department of Biology, Division of Microbiology, Erlangen, Germany
| | - Douglas E. Berg
- Division of Infectious Disease, Department of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Yoshio Yamaoka
- Oita University Faculty of Medicine, Department Environmental and Preventive Medicine, Yufu, Japan
| | - Heinrich Sticht
- Friedrich Alexander University Erlangen-Nuremberg, Bioinformatics, Institute for Biochemistry, Erlangen, Germany
| | - Nicole Tegtmeyer
- Friedrich Alexander University Erlangen-Nuremberg, Department of Biology, Division of Microbiology, Erlangen, Germany
- * E-mail:
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48
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Perna AM, Schmidt T, Fugmann T, Tegtmeyer N, Backert S, Wessler S, Schneider G. Peptide lineup against Gram-negative bacterial infection – first-in-class peptide inhibitor of H. pylori HtrA. J Cheminform 2014. [PMCID: PMC3980066 DOI: 10.1186/1758-2946-6-s1-p46] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Pachathundikandi SK, Tegtmeyer N, Backert S. Signal transduction of Helicobacter pylori during interaction with host cell protein receptors of epithelial and immune cells. Gut Microbes 2013; 4:454-74. [PMID: 24280762 PMCID: PMC3928158 DOI: 10.4161/gmic.27001] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Helicobacter pylori infections can induce pathologies ranging from chronic gastritis, peptic ulceration to gastric cancer. Bacterial isolates harbor numerous well-known adhesins, vacuolating cytotoxin VacA, protease HtrA, urease, peptidoglycan, and type IV secretion systems (T4SS). It appears that H. pylori targets more than 40 known host protein receptors on epithelial or immune cells. A series of T4SS components such as CagL, CagI, CagY, and CagA can bind to the integrin α 5β 1 receptor. Other targeted membrane-based receptors include the integrins αvβ 3, αvβ 5, and β 2 (CD18), RPTP-α/β, GP130, E-cadherin, fibronectin, laminin, CD46, CD74, ICAM1/LFA1, T-cell receptor, Toll-like receptors, and receptor tyrosine kinases EGFR, ErbB2, ErbB3, and c-Met. In addition, H. pylori is able to activate the intracellular receptors NOD1, NOD2, and NLRP3 with important roles in innate immunity. Here we review the interplay of various bacterial factors with host protein receptors. The contribution of these interactions to signal transduction and pathogenesis is discussed.
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Backert S, Boehm M, Wessler S, Tegtmeyer N. Transmigration route of Campylobacter jejuni across polarized intestinal epithelial cells: paracellular, transcellular or both? Cell Commun Signal 2013; 11:72. [PMID: 24079544 PMCID: PMC3850506 DOI: 10.1186/1478-811x-11-72] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Accepted: 09/18/2013] [Indexed: 02/08/2023] Open
Abstract
Intact intercellular junctions and cellular matrix contacts are crucial structural components for the formation and maintenance of epithelial barrier functions in humans to control the commensal flora and protect against intruding microbes. Campylobacter jejuni is one of the most important zoonotic pathogens causing food-borne gastroenteritis and potentially more severe diseases such as reactive arthritis or Guillain–Barré syndrome. Crossing the intestinal epithelial barrier and host cell invasion by C. jejuni are considered to represent the primary reasons of gut tissue damage in humans and various animal model systems including monkeys, piglets, rabbits, hamsters and ferrets. C. jejuni is also able to invade underlying tissues such as the lamina propria, can enter the bloodstream, and possibly reach distinct organs such as spleen, liver or mesenteric lymph nodes. However, the molecular mechanisms as well as major bacterial and host cell factors involved in these activities are poorly understood. Various models exist by which the pathogen can trigger its own transmigration across polarized intestinal epithelial cells in vitro, the paracellular and/or transcellular mechanism. Recent studies suggest that bacterial factors such as flagellum, serine protease HtrA and lipooligosaccharide LOS may play an active role in bacterial transmigration. Here we review our knowledge on transmigration of C. jejuni as well as some other Campylobacter species, and discuss the pros and cons for the route(s) taken to travel across polarized epithelial cell monolayers. These studies provide fresh insights into the infection strategies employed by this important pathogen.
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Affiliation(s)
- Steffen Backert
- Department of Biology, Institute for Microbiology, Friedrich Alexander University Erlangen/Nuremberg, Staudtstr, 5, D-91058, Erlangen, Germany.
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