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Shirani M, Shariati S, Bazdar M, Sojoudi Ghamnak F, Moradi M, Shams Khozani R, Taki E, Arabsorkhi Z, Heidary M, Eskandari DB. The immunopathogenesis of Helicobacter pylori-induced gastric cancer: a narrative review. Front Microbiol 2024; 15:1395403. [PMID: 39035439 PMCID: PMC11258019 DOI: 10.3389/fmicb.2024.1395403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2024] [Accepted: 05/06/2024] [Indexed: 07/23/2024] Open
Abstract
Helicobacter pylori infection is a well-established risk factor for the development of gastric cancer (GC). Understanding the immunopathogenesis underlying this association is crucial for developing effective preventive and therapeutic strategies. This narrative review comprehensively explores the immunopathogenesis of H. pylori-induced GC by delving into several key aspects, emphasizing the pivotal roles played by H. pylori virulence factors, including cytotoxin-associated gene A (cagA) and vacuolating cytotoxin A (vacA), blood group antigen-binding adhesin (babA), and sialic acid binding adhesin (sabA). Moreover, the review focuses on the role of toll-like receptors (TLRs) and cytokines in the complex interplay between chronic infection and gastric carcinogenesis. Finally, the study examines the association between H. pylori evasion of the innate and adaptive immune response and development of GC. A comprehensive understanding of the immunopathogenesis of H. pylori-induced GC is essential for designing targeted interventions to prevent and manage this disease. Further research is warranted to elucidate the intricate immune responses involved and identify potential therapeutic targets to improve patient outcomes.
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Affiliation(s)
- Maryam Shirani
- Toxicology Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Saeedeh Shariati
- Toxicology Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
- Student Research Committee, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Monireh Bazdar
- School of Medicine, Razi Hospital, Ilam University of Medical Sciences, Ilam, Iran
| | | | - Melika Moradi
- Department of Microbiology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | | | - Elahe Taki
- Department of Microbiology, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Zahra Arabsorkhi
- Department of Medical Genetics, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
| | - Mohsen Heidary
- Department of Laboratory Sciences, School of Paramedical Sciences, Sabzevar University of Medical Sciences, Sabzevar, Iran
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Cui L, Shi X, Li H, Wang S, Guo L, Lan Z, Dai Y, Zhang Q, Wu Y, Liu W. Crystal structures and solution conformations of HtrA from Helicobacter pylori reveal pH-dependent oligomeric conversion and conformational rearrangements. Int J Biol Macromol 2023:125274. [PMID: 37301353 DOI: 10.1016/j.ijbiomac.2023.125274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 05/06/2023] [Accepted: 06/07/2023] [Indexed: 06/12/2023]
Abstract
Helicobacter pylori is a Gram-negative microaerophilic bacterium that infects over 50 % of the world's population, making it a major risk factor for chronic gastritis, ulcer diseases of the stomach and duodenum, MALT lymphoma, and gastric cancer. The clinical consequences of H. pylori infection are closely linked with the expression of virulence factors secreted by the bacterium. One such virulence factor is high temperature requirement A (HtrA), which possesses chaperone and serine protease activity. In the host stomach, HtrA secreted from H. pylori (HpHtrA) disrupts intercellular adhesions by cleaving epithelial adhesion proteins including E-cadherin and desmoglein-2. This disruption causes intercellular junctions to open, allowing the bacterium to pass through the epithelial barrier, access the intercellular space, and colonize the gastric mucosa. HtrA proteases are well known for their structural complexity, reflected in their diverse oligomer forms and multi-tasking activities in both prokaryotes and eukaryotes. In this study, we determined crystal structures and solution conformations of HpHtrA monomer and trimer, which revealed large domain rearrangements between them. Notably, this is the first report of a monomeric structure in the HtrA family. We further found a pH-dependent dynamic trimer-to-monomer conversion and concurrent conformational changes that seem closely linked with a pH-sensing ability through the protonation of certain Asp residues. These results advance our understanding of the functional roles and the related mechanisms of this protease in bacterial infection, which may shed light on the development of HtrA-targeted therapies for H. pylori-associated diseases.
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Affiliation(s)
- Liwei Cui
- Institute of Immunology, PLA, Army Medical University, Chongqing 400038, China; Department of Tropical Medicine and Infectious Diseases, Hainan Hospital of Chinese PLA General Hospital, Sanya, Hainan 572000, China
| | - Xiangrui Shi
- Department of Obstetrics and Gynecology, Daping Hospital, Army Medical University, Chongqing 400042, China
| | - Huiling Li
- Department of Tropical Medicine and Infectious Diseases, Hainan Hospital of Chinese PLA General Hospital, Sanya, Hainan 572000, China
| | - Sheng Wang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Avenue, Wuhan, Hubei 430074, China
| | - Ling Guo
- Institute of Immunology, PLA, Army Medical University, Chongqing 400038, China; Center for drug evaluation and inspection of Chongqing Medical Products Administration, Chongqing 401120, China
| | - Zhu Lan
- Institute of Immunology, PLA, Army Medical University, Chongqing 400038, China
| | - Yujie Dai
- Department of Obstetrics and Gynecology, Daping Hospital, Army Medical University, Chongqing 400042, China
| | - Qinghua Zhang
- Department of Obstetrics and Gynecology, Daping Hospital, Army Medical University, Chongqing 400042, China.
| | - Yuzhang Wu
- Institute of Immunology, PLA, Army Medical University, Chongqing 400038, China.
| | - Wei Liu
- Institute of Immunology, PLA, Army Medical University, Chongqing 400038, China.
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Wessler S, Posselt G. Bacterial Proteases in Helicobacter pylori Infections and Gastric Disease. Curr Top Microbiol Immunol 2023; 444:259-277. [PMID: 38231222 DOI: 10.1007/978-3-031-47331-9_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
Helicobacter pylori (H. pylori) proteases have become a major focus of research in recent years, because they not only have an important function in bacterial physiology, but also directly alter host cell functions. In this review, we summarize recent findings on extracellular H. pylori proteases that target host-derived substrates to facilitate bacterial pathogenesis. In particular, the secreted H. pylori collagenase (Hp0169), the metalloprotease Hp1012, or the serine protease High temperature requirement A (HtrA) are of great interest. Specifically, various host cell-derived substrates were identified for HtrA that directly interfere with the gastric epithelial barrier allowing full pathogenesis. In light of increasing antibiotic resistance, the development of inhibitory compounds for extracellular proteases as potential targets is an innovative field that offers alternatives to existing therapies.
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Affiliation(s)
- Silja Wessler
- Department of Biosciences and Medical Biology, Laboratory for Microbial Infection and Cancer, Paris-Lodron University of Salzburg, Salzburg, Austria.
- Cancer Cluster Salzburg and Allergy-Cancer-BioNano Research Centre, Salzburg, Austria.
| | - Gernot Posselt
- Department of Biosciences and Medical Biology, Laboratory for Microbial Infection and Cancer, Paris-Lodron University of Salzburg, Salzburg, Austria
- Cancer Cluster Salzburg and Allergy-Cancer-BioNano Research Centre, Salzburg, Austria
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A Regulatory SRNA Rli43 Is Involved in the Modulation of Biofilm Formation and Virulence in Listeria monocytogenes. Pathogens 2022; 11:pathogens11101137. [PMID: 36297193 PMCID: PMC9606912 DOI: 10.3390/pathogens11101137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 09/11/2022] [Accepted: 09/28/2022] [Indexed: 11/24/2022] Open
Abstract
Small RNAs (sRNAs) are a kind of regulatory molecule that can modulate gene expression at the post-transcriptional level, thereby involving alteration of the physiological characteristics of bacteria. However, the regulatory roles and mechanisms of most sRNAs remain unknown in Listeria monocytogenes(L. monocytogenes). To explore the regulatory roles of sRNA Rli43 in L. monocytogenes, the rli43 gene deletion strain LM-Δrli43 and complementation strain LM-Δrli43-rli43 were constructed to investigate the effects of Rli43 on responses to environmental stress, biofilm formation, and virulence, respectively. Additionally, Rli43-regulated target genes were identified using bioinformatic analysis tools and a bacterial dual plasmid reporter system based on E. coli. The results showed that the intracellular expression level of the rli43 gene was significantly upregulated compared with those under extracellular conditions. Compared with the parental and complementation strains, the environmental adaptation, motility, biofilm formation, adhesion, invasion, and intracellular survival of LM-Δrli43 were significantly reduced, respectively, whereas the LD50 of LM-Δrli43 was significantly elevated in BALB/c mice. Furthermore, the bacterial loads and pathological damages were alleviated, suggesting that sRNA Rli43 was involved in the modulation of the virulence of L. monocytogenes. It was confirmed that Rli43 may complementarily pair with the 5'-UTR (-47--55) of HtrA mRNA, thereby regulating the expression level of HtrA protein at the post-transcriptional level. These findings suggest that Rli43-mediated control was involved in the modulation of environmental adaptation, biofilm formation, and virulence in L. monocytogenes.
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Bernegger S, Hutterer E, Zarzecka U, Schmidt TP, Huemer M, Widlroither I, Posselt G, Skorko-Glonek J, Wessler S. E-Cadherin Orthologues as Substrates for the Serine Protease High Temperature Requirement A (HtrA). Biomolecules 2022; 12:356. [PMID: 35327548 PMCID: PMC8945801 DOI: 10.3390/biom12030356] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 02/18/2022] [Accepted: 02/22/2022] [Indexed: 12/10/2022] Open
Abstract
Helicobacter pylori (H. pylori) expresses the serine protease and chaperone High temperature requirement A (HtrA) that is involved in periplasmic unfolded protein stress response. Additionally, H. pylori-secreted HtrA directly cleaves the human cell adhesion molecule E-cadherin leading to a local disruption of intercellular adhesions during pathogenesis. HtrA-mediated E-cadherin cleavage has been observed in response to a broad range of pathogens, implying that it is a prevalent mechanism in humans. However, less is known whether E-cadherin orthologues serve as substrates for bacterial HtrA. Here, we compared HtrA-mediated cleavage of human E-cadherin with murine, canine, and simian E-cadherin in vitro and during bacterial infection. We found that HtrA targeted mouse and dog E-cadherin equally well, whereas macaque E-cadherin was less fragmented in vitro. We stably re-expressed orthologous E-cadherin (Cdh1) in a CRISPR/Cas9-mediated cdh1 knockout cell line to investigate E-cadherin shedding upon infection using H. pylori wildtype, an isogenic htrA deletion mutant, or complemented mutants as bacterial paradigms. In Western blot analyses and super-resolution microscopy, we demonstrated that H. pylori efficiently cleaved E-cadherin orthologues in an HtrA-dependent manner. These data extend previous knowledge to HtrA-mediated E-cadherin release in mammals, which may shed new light on bacterial infections in non-human organisms.
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Affiliation(s)
- Sabine Bernegger
- Department of Biosciences and Medical Biology, Division of Microbial Infection and Cancer, Paris-Lodron University of Salzburg, 5020 Salzburg, Austria; (S.B.); (E.H.); (T.P.S.); (M.H.); (I.W.); (G.P.)
| | - Evelyn Hutterer
- Department of Biosciences and Medical Biology, Division of Microbial Infection and Cancer, Paris-Lodron University of Salzburg, 5020 Salzburg, Austria; (S.B.); (E.H.); (T.P.S.); (M.H.); (I.W.); (G.P.)
| | - Urszula Zarzecka
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdańsk, 80-308 Gdańsk, Poland; (U.Z.); (J.S.-G.)
| | - Thomas P. Schmidt
- Department of Biosciences and Medical Biology, Division of Microbial Infection and Cancer, Paris-Lodron University of Salzburg, 5020 Salzburg, Austria; (S.B.); (E.H.); (T.P.S.); (M.H.); (I.W.); (G.P.)
| | - Markus Huemer
- Department of Biosciences and Medical Biology, Division of Microbial Infection and Cancer, Paris-Lodron University of Salzburg, 5020 Salzburg, Austria; (S.B.); (E.H.); (T.P.S.); (M.H.); (I.W.); (G.P.)
| | - Isabella Widlroither
- Department of Biosciences and Medical Biology, Division of Microbial Infection and Cancer, Paris-Lodron University of Salzburg, 5020 Salzburg, Austria; (S.B.); (E.H.); (T.P.S.); (M.H.); (I.W.); (G.P.)
| | - Gernot Posselt
- Department of Biosciences and Medical Biology, Division of Microbial Infection and Cancer, Paris-Lodron University of Salzburg, 5020 Salzburg, Austria; (S.B.); (E.H.); (T.P.S.); (M.H.); (I.W.); (G.P.)
| | - Joanna Skorko-Glonek
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdańsk, 80-308 Gdańsk, Poland; (U.Z.); (J.S.-G.)
| | - Silja Wessler
- Department of Biosciences and Medical Biology, Division of Microbial Infection and Cancer, Paris-Lodron University of Salzburg, 5020 Salzburg, Austria; (S.B.); (E.H.); (T.P.S.); (M.H.); (I.W.); (G.P.)
- Cancer Cluster Salzburg and Allergy Cancer BioNano Research Centre, University of Salzburg, Hellbrunner Strasse 34, 5020 Salzburg, Austria
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Bernegger S, Vidmar R, Fonovic M, Posselt G, Turk B, Wessler S. Identification of Desmoglein-2 as a novel target of Helicobacter pylori HtrA in epithelial cells. Cell Commun Signal 2021; 19:108. [PMID: 34742300 PMCID: PMC8571890 DOI: 10.1186/s12964-021-00788-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 09/14/2021] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND High temperature requirement A (HtrA) is an active serine protease secreted by the group-I carcinogen Helicobacter pylori (H. pylori). The human cell adhesion protein and tumor suppressor E-cadherin (hCdh1) expressed on the surface of gastric epithelial cells was identified as the first HtrA substrate. HtrA-mediated hCdh1 cleavage and subsequent disruption of intercellular adhesions are considered as important steps in H. pylori pathogenesis. In this study, we performed a proteomic profiling of H. pylori HtrA (HpHtrA) to decipher the complex mechanism of H. pylori interference with the epithelial barrier integrity. RESULTS Using a proteomic approach we identified human desmoglein-2 (hDsg2), neuropilin-1, ephrin-B2, and semaphorin-4D as novel extracellular HpHtrA substrates and confirmed the well characterized target hCdh1. HpHtrA-mediated hDsg2 cleavage was further analyzed by in vitro cleavage assays using recombinant proteins. In infection experiments, we demonstrated hDsg2 shedding from H. pylori-colonized MKN28 and NCI-N87 cells independently of pathogen-induced matrix-metalloproteases or ADAM10 and ADAM17. CONCLUSIONS Characterizing the substrate specificity of HpHtrA revealed efficient hDsg2 cleavage underlining the importance of HpHtrA in opening intercellular junctions. Video Abstract.
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Affiliation(s)
- Sabine Bernegger
- Division of Microbiology, Department of Biosciences, Paris-Lodron University of Salzburg, Billroth Str. 11, 5020 Salzburg, Austria
| | - Robert Vidmar
- Department of Biochemistry and Molecular and Structural Biology, Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
| | - Marko Fonovic
- Department of Biochemistry and Molecular and Structural Biology, Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
| | - Gernot Posselt
- Division of Microbiology, Department of Biosciences, Paris-Lodron University of Salzburg, Billroth Str. 11, 5020 Salzburg, Austria
| | - Boris Turk
- Department of Biochemistry and Molecular and Structural Biology, Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
| | - Silja Wessler
- Division of Microbiology, Department of Biosciences, Paris-Lodron University of Salzburg, Billroth Str. 11, 5020 Salzburg, Austria
- Cancer Cluster Salzburg and Allergy-Cancer-BioNano Research Centre, University of Salzburg, Billrothstrasse 11, 5020 Salzburg, Austria
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A novel FRET peptide assay reveals efficient Helicobacter pylori HtrA inhibition through zinc and copper binding. Sci Rep 2020; 10:10563. [PMID: 32601479 PMCID: PMC7324608 DOI: 10.1038/s41598-020-67578-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Accepted: 06/09/2020] [Indexed: 12/21/2022] Open
Abstract
Helicobacter pylori (H. pylori) secretes the chaperone and serine protease high temperature requirement A (HtrA) that cleaves gastric epithelial cell surface proteins to disrupt the epithelial integrity and barrier function. First inhibitory lead structures have demonstrated the essential role of HtrA in H. pylori physiology and pathogenesis. Comprehensive drug discovery techniques allowing high-throughput screening are now required to develop effective compounds. Here, we designed a novel fluorescence resonance energy transfer (FRET) peptide derived from a gel-based label-free proteomic approach (direct in-gel profiling of protease specificity) as a valuable substrate for H. pylori HtrA. Since serine proteases are often sensitive to metal ions, we investigated the influence of different divalent ions on the activity of HtrA. We identified Zn++ and Cu++ ions as inhibitors of H. pylori HtrA activity, as monitored by in vitro cleavage experiments using casein or E-cadherin as substrates and in the FRET peptide assay. Putative binding sites for Zn++ and Cu++ were then analyzed in thermal shift and microscale thermophoresis assays. The findings of this study will contribute to the development of novel metal ion-dependent protease inhibitors, which might help to fight bacterial infections.
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Zarzecka U, Harrer A, Zawilak-Pawlik A, Skorko-Glonek J, Backert S. Chaperone activity of serine protease HtrA of Helicobacter pylori as a crucial survival factor under stress conditions. Cell Commun Signal 2019; 17:161. [PMID: 31796064 PMCID: PMC6892219 DOI: 10.1186/s12964-019-0481-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 11/11/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Serine protease HtrA exhibits both proteolytic and chaperone activities, which are involved in cellular protein quality control. Moreover, HtrA is an important virulence factor in many pathogens including Helicobacter pylori, for which the crucial stage of infection is the cleavage of E-cadherin and other cell-to-cell junction proteins. METHODS The in vitro study of H. pylori HtrA (HtrAHp) chaperone activity was carried out using light scattering assays and investigation of lysozyme protein aggregates. We produced H. pylori ∆htrA deletion and HtrAHp point mutants without proteolytic activity in strain N6 and investigated the survival of the bacteria under thermal, osmotic, acidic and general stress conditions as well as the presence of puromycin or metronidazole using serial dilution tests and disk diffusion method. The levels of cellular and secreted proteins were examined using biochemical fraction and Western blotting. We also studied the proteolytic activity of secreted HtrAHp using zymography and the enzymatic digestion of β-casein. Finally, the consequences of E-cadherin cleavage were determined by immunofluorescence microscopy. RESULTS We demonstrate that HtrAHp displays chaperone activity that inhibits the aggregation of lysozyme and is stable under various pH and temperature conditions. Next, we could show that N6 expressing only HtrA chaperone activity grow well under thermal, pH and osmotic stress conditions, and in the presence of puromycin or metronidazole. In contrast, in the absence of the entire htrA gene the bacterium was more sensitive to a number of stresses. Analysing the level of cellular and secreted proteins, we noted that H. pylori lacking the proteolytic activity of HtrA display reduced levels of secreted HtrA. Moreover, we compared the amounts of secreted HtrA from several clinical H. pylori strains and digestion of β-casein. We also demonstrated a significant effect of the HtrAHp variants during infection of human epithelial cells and for E-cadherin cleavage. CONCLUSION Here we identified the chaperone activity of the HtrAHp protein and have proven that this activity is important and sufficient for the survival of H. pylori under multiple stress conditions. We also pinpointed the importance of HtrAHp chaperone activity for E- cadherin degradation and therefore for the virulence of this eminent pathogen.
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Affiliation(s)
- Urszula Zarzecka
- Division of Microbiology, Department of Biology, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany.,Department of General and Medical Biochemistry, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Aileen Harrer
- Division of Microbiology, Department of Biology, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Anna Zawilak-Pawlik
- Department of Microbiology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - Joanna Skorko-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-University Erlangen-Nürnberg, Erlangen, Germany.
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Ansari S, Yamaoka Y. Helicobacter pylori Virulence Factors Exploiting Gastric Colonization and its Pathogenicity. Toxins (Basel) 2019; 11:E677. [PMID: 31752394 PMCID: PMC6891454 DOI: 10.3390/toxins11110677] [Citation(s) in RCA: 130] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 11/15/2019] [Accepted: 11/16/2019] [Indexed: 02/07/2023] Open
Abstract
Helicobacter pylori colonizes the gastric epithelial cells of at least half of the world's population, and it is the strongest risk factor for developing gastric complications like chronic gastritis, ulcer diseases, and gastric cancer. To successfully colonize and establish a persistent infection, the bacteria must overcome harsh gastric conditions. H. pylori has a well-developed mechanism by which it can survive in a very acidic niche. Despite bacterial factors, gastric environmental factors and host genetic constituents together play a co-operative role for gastric pathogenicity. The virulence factors include bacterial colonization factors BabA, SabA, OipA, and HopQ, and the virulence factors necessary for gastric pathogenicity include the effector proteins like CagA, VacA, HtrA, and the outer membrane vesicles. Bacterial factors are considered more important. Here, we summarize the recent information to better understand several bacterial virulence factors and their role in the pathogenic mechanism.
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Affiliation(s)
- Shamshul Ansari
- Department of Microbiology, Chitwan Medical College and Teaching Hospital, Bharatpur 44200, Chitwan, Nepal;
| | - Yoshio Yamaoka
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Idaigaoka, Hasama-machi, Yufu, Oita 879-5593, Japan
- Global Oita Medical Advanced Research Center for Health, Idaigaoka, Hasama-machi, Yufu, Oita 879-5593, Japan
- Department of Medicine, Gastroenterology and Hepatology Section, Baylor College of Medicine, 2002 Holcombe Blvd., Houston, TX 77030, USA
- Borneo Medical and Health Research Centre, Universiti Malaysia Sabah, Kota Kinabaru, Sabah 88400, Malaysia
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Activity and Functional Importance of Helicobacter pylori Virulence Factors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1149:35-56. [PMID: 31016624 DOI: 10.1007/5584_2019_358] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Helicobacter pylori is a very successful Gram-negative pathogen colonizing the stomach of humans worldwide. Infections with this bacterium can generate pathologies ranging from chronic gastritis and peptic ulceration to gastric cancer. The best characterized H. pylori virulence factors that cause direct cell damage include an effector protein encoded by the cytotoxin-associated gene A (CagA), a type IV secretion system (T4SS) encoded in the cag-pathogenicity island (cag PAI), vacuolating cytotoxin A (VacA), γ-glutamyl transpeptidase (GGT), high temperature requirement A (HtrA, a serine protease) and cholesterol glycosyl-transferase (CGT). Since these H. pylori factors are either surface-exposed, secreted or translocated, they can directly interact with host cell molecules and are able to hijack cellular functions. Studies on these bacterial factors have progressed substantially in recent years. Here, we review the current status in the characterization of signaling cascades by these factors in vivo and in vitro, which comprise the disruption of cell-to-cell junctions, induction of membrane rearrangements, cytoskeletal dynamics, proliferative, pro-inflammatory, as well as, pro-apoptotic and anti-apoptotic responses or immune evasion. The impact of these signal transduction modules in the pathogenesis of H. pylori infections is discussed.
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11
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Zarzecka U, Modrak-Wójcik A, Figaj D, Apanowicz M, Lesner A, Bzowska A, Lipinska B, Zawilak-Pawlik A, Backert S, Skorko-Glonek J. Properties of the HtrA Protease From Bacterium Helicobacter pylori Whose Activity Is Indispensable for Growth Under Stress Conditions. Front Microbiol 2019; 10:961. [PMID: 31130939 PMCID: PMC6509562 DOI: 10.3389/fmicb.2019.00961] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 04/16/2019] [Indexed: 12/22/2022] Open
Abstract
The protease high temperature requirement A from the gastric pathogen Helicobacter pylori (HtrAHp) belongs to the well conserved family of serine proteases. HtrAHp is an important secreted virulence factor involved in the disruption of tight and adherens junctions during infection. Very little is known about the function of HtrAHp in the H. pylori cell physiology due to the lack of htrA knockout strains. Here, using a newly constructed ΔhtrA mutant strain, we found that bacteria deprived of HtrAHp showed increased sensitivity to certain types of stress, including elevated temperature, pH and osmotic shock, as well as treatment with puromycin. These data indicate that HtrAHp plays a protective role in the H. pylori cell, presumably associated with maintenance of important periplasmic and outer membrane proteins. Purified HtrAHp was shown to be very tolerant to a wide range of temperature and pH values. Remarkably, the protein exhibited a very high thermal stability with the melting point (Tm) values of above 85°C. Moreover, HtrAHp showed the capability to regain its active structure following treatment under denaturing conditions. Taken together, our work demonstrates that HtrAHp is well adapted to operate under harsh conditions as an exported virulence factor, but also inside the bacterial cell as an important component of the protein quality control system in the stressed cellular envelope.
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Affiliation(s)
- Urszula Zarzecka
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdańsk, Gdańsk, Poland.,Division of Microbiology, Department of Biology, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Anna Modrak-Wójcik
- Division of Biophysics, Faculty of Physics, Institute of Experimental Physics, University of Warsaw, Warsaw, Poland
| | - Donata Figaj
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Malgorzata Apanowicz
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Adam Lesner
- Department of Environmental Technology, Faculty of Chemistry, University of Gdańsk, Gdańsk, Poland
| | - Agnieszka Bzowska
- Division of Biophysics, Faculty of Physics, Institute of Experimental Physics, University of Warsaw, Warsaw, Poland
| | - Barbara Lipinska
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Anna Zawilak-Pawlik
- Department of Microbiology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
| | - Steffen Backert
- Division of Microbiology, Department of Biology, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Joanna Skorko-Glonek
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
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12
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Zhang Z, Huang Q, Tao X, Song G, Zheng P, Li H, Sun H, Xia W. The unique trimeric assembly of the virulence factor HtrA from Helicobacter pylori occurs via N-terminal domain swapping. J Biol Chem 2019; 294:7990-8000. [PMID: 30936204 DOI: 10.1074/jbc.ra119.007387] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 03/27/2019] [Indexed: 12/12/2022] Open
Abstract
Knowledge of the molecular mechanisms of specific bacterial virulence factors can significantly contribute to antibacterial drug discovery. Helicobacter pylori is a Gram-negative microaerophilic bacterium that infects almost half of the world's population, leading to gastric disorders and even gastric cancer. H. pylori expresses a series of virulence factors in the host, among which high-temperature requirement A (HpHtrA) is a newly identified serine protease secreted by H. pylori. HpHtrA cleaves the extracellular domain of the epithelial cell surface adhesion protein E-cadherin and disrupts gastric epithelial cell junctions, allowing H. pylori to access the intercellular space. Here we report the first crystal structure of HpHtrA at 3.0 Å resolution. The structure revealed a new type of HtrA protease trimer stabilized by unique N-terminal domain swapping distinct from other known HtrA homologs. We further observed that truncation of the N terminus completely abrogates HpHtrA trimer formation as well as protease activity. In the presence of unfolded substrate, HpHtrA assembled into cage-like 12-mers or 24-mers. Combining crystallographic, biochemical, and mutagenic data, we propose a mechanistic model of how HpHtrA recognizes and cleaves the well-folded E-cadherin substrate. Our study provides a fundamental basis for the development of anti-H. pylori agents by using a previously uncharacterized HtrA protease as a target.
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Affiliation(s)
- Zhemin Zhang
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou, 510275, China
| | - Qi Huang
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou, 510275, China
| | - Xuan Tao
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou, 510275, China
| | - Guobing Song
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Peng Zheng
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Hongyan Li
- Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Hongzhe Sun
- Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Wei Xia
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou, 510275, China.
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13
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Neddermann M, Backert S. How many protein molecules are secreted by single
Helicobacter pylori
cells: Quantification of serine protease HtrA. Cell Microbiol 2019; 21:e13022. [DOI: 10.1111/cmi.13022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 02/20/2019] [Accepted: 02/23/2019] [Indexed: 12/16/2022]
Affiliation(s)
- Matthias Neddermann
- Department of Biology, Division of MicrobiologyFriedrich Alexander University Erlangen Erlangen Germany
| | - Steffen Backert
- Department of Biology, Division of MicrobiologyFriedrich Alexander University Erlangen Erlangen Germany
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14
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Ansari S, Gantuya B, Tuan VP, Yamaoka Y. Diffuse Gastric Cancer: A Summary of Analogous Contributing Factors for Its Molecular Pathogenicity. Int J Mol Sci 2018; 19:ijms19082424. [PMID: 30115886 PMCID: PMC6121269 DOI: 10.3390/ijms19082424] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 08/08/2018] [Accepted: 08/14/2018] [Indexed: 12/16/2022] Open
Abstract
Gastric cancer is the third leading cause of cancer-related deaths and ranks as the fifth most common cancer worldwide. Incidence and mortality differ depending on the geographical region and gastric cancer ranks first in East Asian countries. Although genetic factors, gastric environment, and Helicobacter pylori infection have been associated with the pathogenicity and development of intestinal-type gastric cancer that follows the Correa’s cascade, the pathogenicity of diffuse-type gastric cancer remains mostly unknown and undefined. However, genetic abnormalities in the cell adherence factors, such as E-cadherin and cellular activities that cause impaired cell integrity and physiology, have been documented as contributing factors. In recent years, H. pylori infection has been also associated with the development of diffuse-type gastric cancer. Therefore, in this report, we discuss the host factors as well as the bacterial factors that have been reported as associated factors contributing to the development of diffuse-type gastric cancer.
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Affiliation(s)
- Shamshul Ansari
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Yufu-City, Oita 879-5593, Japan.
| | - Boldbaatar Gantuya
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Yufu-City, Oita 879-5593, Japan.
- Department of Internal Medicine, Gastroenterology unit, Mongolian National University of Medical Sciences, Ulaanbaatar-14210, Mongolia.
| | - Vo Phuoc Tuan
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Yufu-City, Oita 879-5593, Japan.
- Department of Endoscopy, Cho Ray Hospital, Ho Chi Minh, Vietnam.
| | - Yoshio Yamaoka
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Yufu-City, Oita 879-5593, Japan.
- Department of Medicine, Gastroenterology and Hepatology Section, Baylor College of Medicine, Houston, TX 77030, USA.
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15
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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] [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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16
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Proteolysis in Helicobacter pylori-Induced Gastric Cancer. Toxins (Basel) 2017; 9:toxins9040134. [PMID: 28398251 PMCID: PMC5408208 DOI: 10.3390/toxins9040134] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 04/03/2017] [Accepted: 04/06/2017] [Indexed: 12/15/2022] Open
Abstract
Persistent infections with the human pathogen and class-I carcinogen Helicobacter pylori (H. pylori) are closely associated with the development of acute and chronic gastritis, ulceration, gastric adenocarcinoma and lymphoma of the mucosa-associated lymphoid tissue (MALT) system. Disruption and depolarization of the epithelium is a hallmark of H. pylori-associated disorders and requires extensive modulation of epithelial cell surface structures. Hence, the complex network of controlled proteolysis which facilitates tissue homeostasis in healthy individuals is deregulated and crucially contributes to the induction and progression of gastric cancer through processing of extracellular matrix (ECM) proteins, cell surface receptors, membrane-bound cytokines, and lateral adhesion molecules. Here, we summarize the recent reports on mechanisms how H. pylori utilizes a variety of extracellular proteases, involving the proteases Hp0169 and high temperature requirement A (HtrA) of bacterial origin, and host matrix-metalloproteinases (MMPs), a disintegrin and metalloproteinases (ADAMs) and tissue inhibitors of metalloproteinases (TIMPs). H. pylori-regulated proteases represent predictive biomarkers and attractive targets for therapeutic interventions in gastric cancer.
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17
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Exploiting the Gastric Epithelial Barrier: Helicobacter pylori’s Attack on Tight and Adherens Junctions. Curr Top Microbiol Immunol 2017; 400:195-226. [DOI: 10.1007/978-3-319-50520-6_9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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18
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Schmidt TP, Goetz C, Huemer M, Schneider G, Wessler S. Calcium binding protects E-cadherin from cleavage by Helicobacter pylori HtrA. Gut Pathog 2016; 8:29. [PMID: 27274359 PMCID: PMC4895972 DOI: 10.1186/s13099-016-0112-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 05/30/2016] [Indexed: 02/07/2023] Open
Abstract
Background The cell adhesion and tumor suppressor protein E-cadherin is an important factor in the establishment and maintenance of epithelial integrity. E-cadherin is a single transmembrane protein, which consists of an intracellular domain (IC), a transmembrane domain (TD), and five extracellular domains (EC). EC domains form homophilic interactions in cis and trans that require calcium binding to the linker region between the EC domains. In our previous studies, we identified the serine protease high temperature requirement A (HtrA) from the human pathogen and class-I carcinogen Helicobacter pylori (H. pylori) as a bacterial E-cadherin-cleaving protease that targets the linker region of the EC domains, thereby disrupting gastric epithelial integrity. However, it remains unclear how calcium binding to the E-cadherin linker regions affects HtrA-mediated cleavage. Results Investigating the influence of calcium on the HtrA-mediated cleavage of recombinant E-cadherin (rCdh1) in vitro, we tested different concentrations of calcium ions and the calcium chelator ethylenediaminetetraacetic acid (EDTA). Calcium efficiently reduced HtrA-mediated E-cadherin fragmentation. Conversely, the addition of EDTA strongly increased cleavage, resulting in a ladder of defined E-cadherin fragments. However, calcium ions did not affect HtrA oligomerization and protease activity as monitored by degradation of the universal protease substrate casein. Finally, addition of ethyleneglycol-bis-tetraacetic acid (EGTA) slightly enhanced E-cadherin cleavage during H. pylori infection of gastric epithelial cells. Conclusions Our results suggest that calcium blocks HtrA-mediated cleavage by interfering with the accessibility of calcium-binding regions between the individual EC domains, which have been identified as cleavage sites of HtrA. Electronic supplementary material The online version of this article (doi:10.1186/s13099-016-0112-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Thomas P Schmidt
- Cancer Cluster Salzburg, Department of Molecular Biology, Division of Microbiology, Paris-Lodron University, Salzburg, Austria
| | - Camilla Goetz
- Cancer Cluster Salzburg, Department of Molecular Biology, Division of Microbiology, Paris-Lodron University, Salzburg, Austria
| | - Markus Huemer
- Cancer Cluster Salzburg, Department of Molecular Biology, Division of Microbiology, Paris-Lodron University, Salzburg, Austria
| | - Gisbert Schneider
- Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland
| | - Silja Wessler
- Cancer Cluster Salzburg, Department of Molecular Biology, Division of Microbiology, Paris-Lodron University, Salzburg, Austria
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19
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Identification of E-cadherin signature motifs functioning as cleavage sites for Helicobacter pylori HtrA. Sci Rep 2016; 6:23264. [PMID: 26983597 PMCID: PMC4794652 DOI: 10.1038/srep23264] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 03/02/2016] [Indexed: 12/19/2022] Open
Abstract
The cell adhesion protein and tumour suppressor E-cadherin exhibits important functions in the prevention of gastric cancer. As a class-I carcinogen, Helicobacter pylori (H. pylori) has developed a unique strategy to interfere with E-cadherin functions. In previous studies, we have demonstrated that H. pylori secretes the protease high temperature requirement A (HtrA) which cleaves off the E-cadherin ectodomain (NTF) on epithelial cells. This opens cell-to-cell junctions, allowing bacterial transmigration across the polarised epithelium. Here, we investigated the molecular mechanism of the HtrA-E-cadherin interaction and identified E-cadherin cleavage sites for HtrA. Mass-spectrometry-based proteomics and Edman degradation revealed three signature motifs containing the [VITA]-[VITA]-x-x-D-[DN] sequence pattern, which were preferentially cleaved by HtrA. Based on these sites, we developed a substrate-derived peptide inhibitor that selectively bound and inhibited HtrA, thereby blocking transmigration of H. pylori. The discovery of HtrA-targeted signature sites might further explain why we detected a stable 90 kDa NTF fragment during H. pylori infection, but also additional E-cadherin fragments ranging from 105 kDa to 48 kDa in in vitro cleavage experiments. In conclusion, HtrA targets E-cadherin signature sites that are accessible in in vitro reactions, but might be partially masked on epithelial cells through functional homophilic E-cadherin interactions.
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20
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Guijarro JA, Cascales D, García-Torrico AI, García-Domínguez M, Méndez J. Temperature-dependent expression of virulence genes in fish-pathogenic bacteria. Front Microbiol 2015. [PMID: 26217329 PMCID: PMC4496569 DOI: 10.3389/fmicb.2015.00700] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Virulence gene expression in pathogenic bacteria is modulated by environmental parameters. A key factor in this expression is temperature. Its effect on virulence gene expression in bacteria infecting warm-blooded hosts is well documented. Transcription of virulence genes in these bacteria is induced upon a shift from low environmental to a higher host temperature (37°C). Interestingly, host temperatures usually correspond to the optimum for growth of these pathogenic bacteria. On the contrary, in ectothermic hosts such as fish, molluscs, and amphibians, infection processes generally occur at a temperature lower than that for the optimal growth of the bacteria. Therefore, regulation of virulence gene expression in response to temperature shift has to be modulated in a different way to that which is found in bacteria infecting warm-blooded hosts. The current understanding of virulence gene expression and its regulation in response to temperature in fish-pathogenic bacteria is limited, but constant extension of our knowledge base is essential to enable a rational approach to the problem of the bacterial fish diseases affecting the aquaculture industry. This is an interesting issue and progress needs to be made in order to diminish the economic losses caused by these diseases. The intention of this review is, for the first time, to compile the scattered results existing in the field in order to lay the groundwork for future research. This article is an overview of those relevant virulence genes that are expressed at temperatures lower than that for optimal bacterial growth in different fish-pathogenic bacteria as well as the principal mechanisms that could be involved in their regulation.
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Affiliation(s)
- José A. Guijarro
- *Correspondence: José A. Guijarro, Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, Instituto de Biotecnología de Asturias, Universidad de Oviedo, C/Julían Clavería 6, 33006 Oviedo, Spain,
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21
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Posselt G, Backert S, Wessler S. The functional interplay of Helicobacter pylori factors with gastric epithelial cells induces a multi-step process in pathogenesis. Cell Commun Signal 2013; 11:77. [PMID: 24099599 PMCID: PMC3851490 DOI: 10.1186/1478-811x-11-77] [Citation(s) in RCA: 142] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 10/01/2013] [Indexed: 12/16/2022] Open
Abstract
Infections with the human pathogen Helicobacter pylori (H. pylori) can lead to severe gastric diseases ranging from chronic gastritis and ulceration to neoplastic changes in the stomach. Development and progress of H. pylori-associated disorders are determined by multifarious bacterial factors. Many of them interact directly with host cells or require specific receptors, while others enter the host cytoplasm to derail cellular functions. Several adhesins (e.g. BabA, SabA, AlpA/B, or OipA) establish close contact with the gastric epithelium as an important first step in persistent colonization. Soluble H. pylori factors (e.g. urease, VacA, or HtrA) have been suggested to alter cell survival and intercellular adhesions. Via a type IV secretion system (T4SS), H. pylori also translocates the effector cytotoxin-associated gene A (CagA) and peptidoglycan directly into the host cytoplasm, where cancer- and inflammation-associated signal transduction pathways can be deregulated. Through these manifold possibilities of interaction with host cells, H. pylori interferes with the complex signal transduction networks in its host and mediates a multi-step pathogenesis.
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Affiliation(s)
- Gernot Posselt
- Division of Molecular Biology, Department of Microbiology, Paris-Lodron University, Salzburg, Austria.
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22
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Stricker RB, Johnson L. Borrelia burgdorferi aggrecanase activity: more evidence for persistent infection in Lyme disease. Front Cell Infect Microbiol 2013; 3:40. [PMID: 23967405 PMCID: PMC3743303 DOI: 10.3389/fcimb.2013.00040] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Accepted: 07/25/2013] [Indexed: 12/29/2022] Open
Abstract
Lyme disease is the most common tickborne illness in the world today. A recent study describes for the first time an enzyme produced by the spirochetal agent of Lyme disease, Borrelia burgdorferi, that cleaves aggrecan, a proteoglycan found in joints and connective tissue. Discovery of the spirochetal aggrecanase raises many questions about the pathogenesis of Lyme arthritis and lends support to the concept of persistent B. burgdorferi infection in patients with chronic Lyme disease symptoms.
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