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Huang H, Zhong W, Wang X, Yang Y, Wu T, Chen R, Liu Y, He F, Li J. The role of gastric microecological dysbiosis in gastric carcinogenesis. Front Microbiol 2023; 14:1218395. [PMID: 37583514 PMCID: PMC10423824 DOI: 10.3389/fmicb.2023.1218395] [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: 05/07/2023] [Accepted: 07/10/2023] [Indexed: 08/17/2023] Open
Abstract
Gastric cancer (GC) is the leading cause of cancer-related death worldwide, and reducing its mortality has become an urgent public health issue. Gastric microecological dysbiosis (including bacteria, fungi, viruses, acid suppressants, antibiotics, and surgery) can lead to gastric immune dysfunction or result in a decrease in dominant bacteria and an increase in the number and virulence of pathogenic microorganisms, which in turn promotes development of GC. This review analyzes the relationship between gastric microecological dysbiosis and GC, elucidates dynamic alterations of the microbiota in Correa's cascade, and identifies certain specific microorganisms as potential biomarkers of GC to aid in early screening and diagnosis. In addition, this paper presents the potential of gastric microbiota transplantation as a therapeutic target for gastric cancer, providing a new direction for future research in this field.
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Affiliation(s)
- Hui Huang
- Chengdu Medical College, Chengdu, Sichuan, China
| | - Wei Zhong
- Chengdu Medical College, Chengdu, Sichuan, China
| | | | - Ying Yang
- Chengdu Medical College, Chengdu, Sichuan, China
| | - Tianmu Wu
- Chengdu Medical College, Chengdu, Sichuan, China
| | - Runyang Chen
- Chengdu Medical College, Chengdu, Sichuan, China
| | - Yanling Liu
- Chengdu Medical College, Chengdu, Sichuan, China
| | - Feng He
- Chengdu Medical College, Chengdu, Sichuan, China
- Department of Gastroenterology, The First Affiliated Hospital of Chengdu Medical College, Chengdu, Sichuan, China
| | - Jun Li
- Chengdu Medical College, Chengdu, Sichuan, China
- Department of Gastroenterology, The First Affiliated Hospital of Chengdu Medical College, Chengdu, Sichuan, China
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2
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Yang J, Liu X, Cheng Y, Zhang J, Ji F, Ling Z. Roles of Plasmacytoid Dendritic Cells in Gastric Cancer. Front Oncol 2022; 12:818314. [PMID: 35311157 PMCID: PMC8927765 DOI: 10.3389/fonc.2022.818314] [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: 11/19/2021] [Accepted: 02/15/2022] [Indexed: 12/24/2022] Open
Abstract
Gastric cancer (GC) is the fifth most common neoplasm and the third most deadly cancer in humans worldwide. Helicobacter pylori infection is the most important causative factor of gastric carcinogenesis, and activates host innate and adaptive immune responses. As key constituents of the tumor immune microenvironment, plasmacytoid dendritic cells (pDCs) are increasingly attracting attention owing to their potential roles in immunosuppression. We recently reported that pDCs have vital roles in the development of immunosuppression in GC. Clarifying the contribution of pDCs to the development and progression of GC may lead to improvements in cancer therapy. In this review, we summarize current knowledge regarding immune modulation in GC, especially the roles of pDCs in GC carcinogenesis and treatment strategies.
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Affiliation(s)
- Jinpu Yang
- Department of Gastroenterology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xia Liu
- Department of Intensive Care Unit, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yiwen Cheng
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Jingchen Zhang
- Department of Intensive Care Unit, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Feng Ji
- Department of Gastroenterology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zongxin Ling
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.,Jinan Microecological Biomedicine Shandong Laboratory, Jinan, China
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3
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Sarkar D, Vijayan R, Gourinath S, Sau AK. A unique aromatic cluster near the active site of H. pylori CPA is essential for catalytic function. Biophys J 2022; 121:248-262. [PMID: 34932956 PMCID: PMC8790187 DOI: 10.1016/j.bpj.2021.12.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 09/16/2021] [Accepted: 12/16/2021] [Indexed: 01/21/2023] Open
Abstract
Polyamines are essential for cell growth and proliferation. In plants and many bacteria, including Helicobacter pylori, the parent polyamine putrescine is only produced through the metabolism of N-carbamoylputrescine by N-carbamoylputrescine amidase (CPA). Thus, CPA is a crucial intermediate enzyme. Moreover, the absence of CPA in humans makes its presence in H. pylori a potential target for the development of new therapeutics against this pathogen. Despite this enzyme's presence in plants and bacteria, its function is not completely explored. Using structure-guided biochemical and biophysical studies on H. pylori CPA, we discovered an aromatic cluster containing four conserved tryptophans near the catalytic site and elucidated its role. Mutational studies revealed that they are individually vital to enzyme function. Unlike wild-type, which forms a hexamer, the Trp to Ala mutants only formed dimers. Interestingly, two other conserved residues, Gln155 and Asp278, interact with the tryptophan cluster and perform similar roles. Our results indicate that aromatic-aromatic and H-bonding contacts between the residues (Trp156-Trp273, Trp196-Gln155, and Trp153-Asp278) play a crucial role in stimulating activity through hexamer formation. Additionally, Trp156 is essential to generating a catalytically efficient hexamer. These results suggest dual roles for the tryptophans; in hexamer formation and in generating its functionally active form, thereby providing a mechanistic understanding into the role of the cluster. We also elucidated the catalytic roles of Glu43, Lys115, and Cys152, which are present at the active site. Our findings highlight, for the first time, the importance of a tryptophan cluster in H. pylori CPA that can be exploited to design therapeutic inhibitors.
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Affiliation(s)
- Ditsa Sarkar
- National Institute of Immunology, New Delhi, India
| | | | | | - Apurba Kumar Sau
- National Institute of Immunology, New Delhi, India,Correspondence:
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Broekaert IJ, Borrelli O, Dolinsek J, Martin-de-Carpi J, Mas E, Miele E, Pienar C, Ribes-Koninckx C, Thomassen R, Thomson M, Tzivinikos C, Benninga M. An ESPGHAN Position Paper on the Use of Breath Testing in Paediatric Gastroenterology. J Pediatr Gastroenterol Nutr 2022; 74:123-137. [PMID: 34292218 DOI: 10.1097/mpg.0000000000003245] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
OBJECTIVES Given a lack of a systematic approach to the use of breath testing in paediatric patients, the aim of this position paper is to provide expert guidance regarding the indications for its use and practical considerations to optimise its utility and safety. METHODS Nine clinical questions regarding methodology, interpretation, and specific indications of breath testing and treatment of carbohydrate malabsorption were addressed by members of the Gastroenterology Committee (GIC) of the European Society for Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN).A systematic literature search was performed from 1983 to 2020 using PubMed, the MEDLINE and Cochrane Database of Systematic Reviews. Grading of Recommendations, Assessment, Development, and Evaluation was applied to evaluate the outcomes.During a consensus meeting, all recommendations were discussed and finalised. In the absence of evidence from randomised controlled trials, recommendations reflect the expert opinion of the authors. RESULTS A total of 22 recommendations were voted on using the nominal voting technique. At first, recommendations on prerequisites and preparation for as well as on interpretation of breath tests are given. Then, recommendations on the usefulness of H2-lactose breath testing, H2-fructose breath testing as well as of breath tests for other types of carbohydrate malabsorption are provided. Furthermore, breath testing is recommended to diagnose small intestinal bacterial overgrowth (SIBO), to control for success of Helicobacter pylori eradication therapy and to diagnose and monitor therapy of exocrine pancreatic insufficiency, but not to estimate oro-caecal transit time (OCTT) or to diagnose and follow-up on celiac disease. CONCLUSIONS Breath tests are frequently used in paediatric gastroenterology mainly assessing carbohydrate malabsorption, but also in the diagnosis of small intestinal overgrowth, fat malabsorption, H. pylori infection as well as for measuring gastrointestinal transit times. Interpretation of the results can be challenging and in addition, pertinent symptoms should be considered to evaluate clinical tolerance.
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Affiliation(s)
- Ilse Julia Broekaert
- Department of Paediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Osvaldo Borrelli
- Department of Paediatric Gastroenterology, Great Ormond Street Hospital, London, UK
| | - Jernej Dolinsek
- Department of Paediatrics, University Medical Centre Maribor, Maribor, Slovenia
| | - Javier Martin-de-Carpi
- Department of Paediatric Gastroenterology, Hepatology and Nutrition, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Emmanuel Mas
- Unité de Gastroentérologie, Hépatologie, Nutrition, Diabétologie et Maladies Héréditaires du Métabolisme, Hôpital des Enfants, CHU de Toulouse, Toulouse, France; IRSD, Université de Toulouse, INSERM, INRA, ENVT, UPS, Toulouse, France
| | - Erasmo Miele
- Department of Translational Medical Science, Section of Paediatrics, University of Naples "Federico", Naples, Italy
| | - Corina Pienar
- Department of Paediatrics, "Victor Babes" University of Medicine and Pharmacy, Timisoara, Romania
| | - Carmen Ribes-Koninckx
- Department of Paediatric Gastroenterology, Hepatology & Nutrition, La Fe University Hospital, Valencia, Spain
| | - Rut Thomassen
- Department of Paediatric Medicine, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Norway
| | - Mike Thomson
- Centre for Paediatric Gastroenterology, Sheffield Children's Hospital, Sheffield, UK
| | - Christos Tzivinikos
- Department of Paediatric Gastroenterology, Al Jalila Children's Specialty Hospital, Dubai, UAE
| | - Marc Benninga
- Department of Paediatric Gastroenterology and Nutrition, Emma Children's Hospital, Amsterdam University Medical Centres, Amsterdam, The Netherlands
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5
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Hsu YT, Ho MH, Lee SP, Kao CY. Preparation of Biomimetic 3D Gastric Model with Photo-Curing Resin and Evaluation the Growth of Helicobacter pylori. Polymers (Basel) 2021; 13:polym13203593. [PMID: 34685352 PMCID: PMC8538753 DOI: 10.3390/polym13203593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 10/12/2021] [Accepted: 10/16/2021] [Indexed: 11/20/2022] Open
Abstract
Three-dimensional (3D) printing technology is now widely used in biomedical developments. Especially, photo-curing systems provide high resolution and precision. The current goal of biomedical 3D printing technology is the printing of human organs, but the current commercial photo-curable materials generally have high mechanical strength that cannot meet the mechanical properties of the object to be printed. In this research, a gastric model was printed using a photo-curing 3D printing technique. To mimic the wrinkle pattern of human gastric tissue, cis-1,4 polyisoprene with different reactive diluents was mixed and identified a formulation that produced a print with human gastric softness. This research discussed the effect of the Young’s modulus of the material and elucidated the relationship between the degree of conversion rate and viscosity. After modifying the cis-1,4 polyisoprene surface from hydrophobic to hydrophilic, we then evaluated its adhesion efficiency for gastric mucin and the gastrointestinal-inhabiting bacterium Helicobacter pylori.
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Affiliation(s)
- Yu-Tung Hsu
- Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan; (Y.-T.H.); (M.-H.H.)
| | - Ming-Hu Ho
- Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan; (Y.-T.H.); (M.-H.H.)
- R&D Center for Membrane Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan
| | - Shiao-Pieng Lee
- Department of Dentistry, Division of Oral and Maxillofacial Surgery, Tri-Service General Hospital, Taipei 11490, Taiwan;
- Department of Biomedical Engineering, National Defense Medical Center, Taipei 11490, Taiwan
| | - Chen-Yu Kao
- Graduate Institute of Biomedical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan
- Biomedical Engineering Research Center, National Defense Medical Center, Taipei 11490, Taiwan
- Correspondence: ; Tel.: +886-2-2730-3676
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6
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Kim HW, Woo HJ, Yang JY, Kim JB, Kim SH. Hesperetin Inhibits Expression of Virulence Factors and Growth of Helicobacter pylori. Int J Mol Sci 2021; 22:ijms221810035. [PMID: 34576198 PMCID: PMC8472136 DOI: 10.3390/ijms221810035] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/09/2021] [Accepted: 09/13/2021] [Indexed: 12/22/2022] Open
Abstract
Helicobacter pylori (H. pylori) is a bacterium known to infect the human stomach. It can cause various gastrointestinal diseases including gastritis and gastric cancer. Hesperetin is a major flavanone component contained in citrus fruits. It has been reported to possess antibacterial, antioxidant, and anticancer effects. However, the antibacterial mechanism of hesperetin against H. pylori has not been reported yet. Therefore, the objective of this study was to determine the inhibitory effects of hesperetin on H. pylori growth and its inhibitory mechanisms. The results of this study showed that hesperetin inhibits the growth of H. pylori reference strains and clinical isolates. Hesperetin inhibits the expression of genes in replication (dnaE, dnaN, dnaQ, and holB) and transcription (rpoA, rpoB, rpoD, and rpoN) machineries of H. pylori. Hesperetin also inhibits the expression of genes related to H. pylori motility (flhA, flaA, and flgE) and adhesion (sabA, alpA, alpB, hpaA, and hopZ). It also inhibits the expression of urease. Hespereti n downregulates major virulence factors such as cytotoxin-associated antigen A (CagA) and vacuolating cytotoxin A (VacA) and decreases the translocation of CagA and VacA proteins into gastric adenocarcinoma (AGS) cells. These results might be due to decreased expression of the type IV secretion system (T4SS) and type V secretion system (T5SS) involved in translocation of CagA and VacA, respectively. The results of this study indicate that hesperetin has antibacterial effects against H. pylori. Thus, hesperetin might be an effective natural product for the eradication of H. pylori.
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Affiliation(s)
- Hyun Woo Kim
- Department of Biomedical Laboratory Science, College of Health Sciences, Yonsei University, Wonju 26493, Korea; (H.W.K.); (J.-B.K.)
| | - Hyun Jun Woo
- Department of Clinical Laboratory Science, Semyung University, Jecheon 27136, Korea;
| | - Ji Yeong Yang
- Division of Crop Foundation, National Institute of Crop Science (NICS), Rural Development Administration (RDA), Wanju 55365, Korea;
| | - Jong-Bae Kim
- Department of Biomedical Laboratory Science, College of Health Sciences, Yonsei University, Wonju 26493, Korea; (H.W.K.); (J.-B.K.)
| | - Sa-Hyun Kim
- Department of Clinical Laboratory Science, Semyung University, Jecheon 27136, Korea;
- Correspondence:
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7
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Host-Like Conditions Are Required for T6SS-Mediated Competition among Vibrio fischeri Light Organ Symbionts. mSphere 2021; 6:e0128820. [PMID: 34287008 PMCID: PMC8386388 DOI: 10.1128/msphere.01288-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Bacteria employ diverse competitive strategies to enhance fitness and promote their own propagation. However, little is known about how symbiotic bacteria modulate competitive mechanisms as they compete for a host niche. The bacterium Vibrio fischeri forms a symbiotic relationship with marine animals and encodes a type VI secretion system (T6SS), which is a contact-dependent killing mechanism used to eliminate competitors during colonization of the Euprymna scolopes squid light organ. Like other horizontally acquired symbionts, V. fischeri experiences changes in its physical and chemical environment during symbiosis establishment. Therefore, we probed both environmental and host-like conditions to identify ecologically relevant cues that control T6SS-dependent competition during habitat transition. Although the T6SS did not confer a competitive advantage for V. fischeri strain ES401 under planktonic conditions, a combination of both host-like pH and viscosity was necessary for T6SS competition. For ES401, high viscosity activates T6SS expression and neutral/acidic pH promotes cell-cell contact for killing, and this pH-dependent phenotype was conserved in the majority of T6SS-encoding strains examined. We also identified a subset of V. fischeri isolates that engaged in T6SS-mediated competition at high viscosity under both planktonic and host-like pH conditions. T6SS phylogeny revealed that strains with pH-dependent phenotypes cluster together to form a subclade within the pH-independent strains, suggesting that V. fischeri may have recently evolved to limit competition to the host niche. IMPORTANCE Bacteria have evolved diverse strategies to compete for limited space and resources. Because these mechanisms can be costly to use, their expression and function are often restricted to specific environments where the benefits outweigh the costs. However, little is known about the specific cues that modulate competitive mechanisms as bacterial symbionts transition between free-living and host habitats. Here, we used the bioluminescent squid and fish symbiont Vibrio fischeri to probe for host and environmental conditions that control interbacterial competition via the type VI secretion system. Our findings identify a new host-specific cue that promotes competition among many but not all V. fischeri isolates, underscoring the utility of studying multiple strains to reveal how competitive mechanisms may be differentially regulated among closely related populations as they evolve to fill distinct niches.
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8
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Abstract
Upper gastrointestinal (GI) bleeding is a common reason for hospital admission in older adult patients and carries a high morbidity and mortality if not properly managed. Risk factors include advanced age, Helicobacter pylori infection, medication use, smoking, and history of liver disease. Patients with known or suspected liver disease and suspected variceal bleeding should also receive antibiotics and somatostatin analogues. Risk stratification scores should be used to determine patients at highest risk for further decompensation. Upper endoscopy is both a diagnostic and therapeutic tool used in the management of upper GI bleeding. Endoscopy should be performed within 24 hours of presentation after appropriate resuscitation. Management of anticoagulation in upper GI bleeding largely depends on the indication for anticoagulation, the risk of continued bleeding with continuing the medication, and the risk of thrombosis with discontinuing the medication. A multidisciplinary approach to the decision of anticoagulation continuation is preferred when possible.
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Affiliation(s)
- Nicholas J Costable
- Department of Medicine, Icahn School of Medicine at Mount Sinai, 1 Gustav L Levy Place, New York, NY 10029, USA
| | - David A Greenwald
- Division of Gastroenterology, Icahn School of Medicine at Mount Sinai, 5 East 98th Street, 11th Floor, New York, NY 10029, USA.
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9
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Baj J, Forma A, Sitarz M, Portincasa P, Garruti G, Krasowska D, Maciejewski R. Helicobacter pylori Virulence Factors-Mechanisms of Bacterial Pathogenicity in the Gastric Microenvironment. Cells 2020; 10:E27. [PMID: 33375694 PMCID: PMC7824444 DOI: 10.3390/cells10010027] [Citation(s) in RCA: 145] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/18/2020] [Accepted: 12/22/2020] [Indexed: 12/11/2022] Open
Abstract
Gastric cancer constitutes one of the most prevalent malignancies in both sexes; it is currently the fourth major cause of cancer-related deaths worldwide. The pathogenesis of gastric cancer is associated with the interaction between genetic and environmental factors, among which infection by Helicobacter pylori (H. pylori) is of major importance. The invasion, survival, colonization, and stimulation of further inflammation within the gastric mucosa are possible due to several evasive mechanisms induced by the virulence factors that are expressed by the bacterium. The knowledge concerning the mechanisms of H. pylori pathogenicity is crucial to ameliorate eradication strategies preventing the possible induction of carcinogenesis. This review highlights the current state of knowledge and the most recent findings regarding H. pylori virulence factors and their relationship with gastric premalignant lesions and further carcinogenesis.
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Affiliation(s)
- Jacek Baj
- Department of Anatomy, Medical University of Lublin, 20-400 Lublin, Poland;
| | - Alicja Forma
- Chair and Department of Forensic Medicine, Medical University of Lublin, 20-090 Lublin, Poland;
| | - Monika Sitarz
- Department of Conservative Dentistry with Endodontics, Medical University of Lublin, 20-090 Lublin, Poland;
| | - Piero Portincasa
- Clinica Medica “Augusto Murri”, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro”, 70124 Bari, Italy;
| | - Gabriella Garruti
- Section of Endocrinology, Department of Emergency and Organ Transplantations, University of Bari “Aldo Moro” Medical School, Piazza G. Cesare 11, 70124 Bari, Italy;
| | - Danuta Krasowska
- Department of Dermatology, Venerology and Paediatric Dermatology of Medical University of Lublin, 20-081 Lublin, Poland;
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10
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Taylor JA, Bratton BP, Sichel SR, Blair KM, Jacobs HM, DeMeester KE, Kuru E, Gray J, Biboy J, VanNieuwenhze MS, Vollmer W, Grimes CL, Shaevitz JW, Salama NR. Distinct cytoskeletal proteins define zones of enhanced cell wall synthesis in Helicobacter pylori. eLife 2020; 9:52482. [PMID: 31916938 PMCID: PMC7012605 DOI: 10.7554/elife.52482] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Accepted: 01/07/2020] [Indexed: 12/15/2022] Open
Abstract
Helical cell shape is necessary for efficient stomach colonization by Helicobacter pylori, but the molecular mechanisms for generating helical shape remain unclear. The helical centerline pitch and radius of wild-type H. pylori cells dictate surface curvatures of considerably higher positive and negative Gaussian curvatures than those present in straight- or curved-rod H. pylori. Quantitative 3D microscopy analysis of short pulses with either N-acetylmuramic acid or D-alanine metabolic probes showed that cell wall growth is enhanced at both sidewall curvature extremes. Immunofluorescence revealed MreB is most abundant at negative Gaussian curvature, while the bactofilin CcmA is most abundant at positive Gaussian curvature. Strains expressing CcmA variants with altered polymerization properties lose helical shape and associated positive Gaussian curvatures. We thus propose a model where CcmA and MreB promote PG synthesis at positive and negative Gaussian curvatures, respectively, and that this patterning is one mechanism necessary for maintaining helical shape. Round spheres, straight rods, and twisting corkscrews, bacteria come in many different shapes. The shape of bacteria is dictated by their cell wall, the strong outer barrier of the cell. As bacteria grow and multiply, they must add to their cell wall while keeping the same basic shape. The cells walls are made from long chain-like molecules via processes that are guided by protein scaffolds within the cell. Many common antibiotics, including penicillin, stop bacterial infections by interrupting the growth of cell walls. Helicobacter pylori is a common bacterium that lives in the gut and, after many years, can cause stomach ulcers and stomach cancer. H. pylori are shaped in a twisting helix, much like a corkscrew. This shape helps H. pylori to take hold and colonize the stomach. It remains unclear how H. pylori creates and maintains its helical shape. The helix is much more curved than other bacteria, and H. pylori does not have the same helpful proteins that other curved bacteria do. If H. pylori grows asymmetrically, adding more material to the cell wall on its long outer side to create a twisting helix, what controls the process? To find out, Taylor et al. grew H. pylori cells and watched how the cell walls took shape. First, a fluorescent dye was attached to the building blocks of the cell wall or to underlying proteins that were thought to help direct its growth. The cells were then imaged in 3D, and images from hundreds of cells were reconstructed to analyze the growth patterns of the bacteria’s cell wall. A protein called CcmA was found most often on the long side of the twisting H. pylori. When the CcmA protein was isolated in a dish, it spontaneously formed sheets and helical bundles, confirming its role as a structural scaffold for the cell wall. When CcmA was absent from the cell of H. pylori, Taylor et al. observed that the pattern of cell growth changed substantially. This work identifies a key component directing the growth of the cell wall of H. pylori and therefore, a new target for antibiotics. Its helical shape is essential for H. pylori to infect the gut, so blocking the action of the CcmA protein may interrupt cell wall growth and prevent stomach infections.
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Affiliation(s)
- Jennifer A Taylor
- Department of Microbiology, University of Washington, Seattle, United States.,Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Benjamin P Bratton
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, United States.,Department of Molecular Biology, Princeton University, Princeton, United States
| | - Sophie R Sichel
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, United States.,Molecular Medicine and Mechanisms of Disease Graduate Program, University of Washington, Seattle, United States
| | - Kris M Blair
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, United States.,Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, United States
| | - Holly M Jacobs
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, United States.,Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, United States
| | - Kristen E DeMeester
- Department of Chemistry and Biochemistry, University of Delaware, Newark, United States
| | - Erkin Kuru
- Department of Genetics, Harvard Medical School, Boston, United States
| | - Joe Gray
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Jacob Biboy
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | | | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Catherine L Grimes
- Department of Chemistry and Biochemistry, University of Delaware, Newark, United States.,Department of Biological Sciences, University of Delaware, Newark, United States
| | - Joshua W Shaevitz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, United States.,Department of Physics, Princeton University, Princeton, United States
| | - Nina R Salama
- Department of Microbiology, University of Washington, Seattle, United States.,Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, United States.,Molecular Medicine and Mechanisms of Disease Graduate Program, University of Washington, Seattle, United States.,Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, United States
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11
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Helicobacter pylori Uses the TlpB Receptor To Sense Sites of Gastric Injury. Infect Immun 2019; 87:IAI.00202-19. [PMID: 31262979 DOI: 10.1128/iai.00202-19] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 06/18/2019] [Indexed: 01/24/2023] Open
Abstract
Helicobacter pylori is a pathogen that chronically colonizes the stomachs of approximately half of the world's population and contributes to the development of gastric inflammation. We demonstrated previously in vivo that H. pylori uses motility to preferentially colonize injury sites in the mouse stomach. However, the chemoreceptor responsible for sensing gastric injury has not yet been identified. In this study, we utilized murine gastric organoids (gastroids) and mutant H. pylori strains to investigate the components necessary for H. pylori chemotaxis. High-intensity 730-nm light (two-photon photodamage) was used to cause single-cell damage in gastroids, and repair of the damage was monitored over time; complete repair occurred within ∼10 min in uninfected gastroids. Wild-type H. pylori accumulated at the damage site after gastric damage induction. In contrast, mutants lacking motility (ΔmotB) or chemotaxis (ΔcheY) did not accumulate at the injury site. Using mutants lacking individual chemoreceptors, we found that only TlpB was required for H. pylori accumulation, while TlpA, TlpC, and TlpD were dispensable. All strains that were able to accumulate at the damage site limited repair. When urea (an identified chemoattractant sensed by TlpB) was microinjected into the gastroid lumen, it prevented the accumulation of H. pylori at damage sites. Overall, our findings demonstrate that H. pylori colonizes and limits repair at damage sites via chemotactic motility that requires the TlpB chemoreceptor to sense signals generated by gastric epithelial cells.
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12
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Darmani H, Am Smadi E, Mb Bataineh S. Blue light emitting diodes cripple Helicobacter pylori by targeting its virulence factors. MINERVA GASTROENTERO 2019; 65:187-192. [PMID: 31293118 DOI: 10.23736/s1121-421x.19.02593-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND The endogenous photosensitizing porphyrins in Helicobacter pylori (H. pylori), make blue light therapy an attractive addition to the armamentarium in the war against this very prevalent and difficult to treat infectious agent. METHODS In the current study we examined in vitro the effect of blue LED (Light Emitting Diode) irradiation for 1-6 minutes on the viability and virulence factors of H. pylori, which allow this microorganism to colonize and establish infection. Specifically, we examined the effects of blue LED on urease production, motility, adhesion and biofilm formation. RESULTS We found that exposure to blue LED for 1-6 minutes significantly decreased the viability of H. pylori and caused decreased urease activity, as well as, swarming motility. Furthermore, blue LED irradiation for 6 minutes caused greater than 50% disruption of preformed mature biofilms of H. pylori, relative to controls. CONCLUSIONS Collectively, the results of our in-vitro study indicate that therapy with blue LED may be an added weapon in the eradication of H. pylori by targeting the virulence factors of this very common pathogen. We envisage that phototherapy will have an adjuvant effect on conventional anti-H. pylori therapy, especially considering its efficacy in biofilm disruption and the fact that microorganisms are unlikely to develop resistance as a result of the multi-target effects.
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Affiliation(s)
- Homa Darmani
- Department of Applied Biological Sciences, Faculty of Science, Jordan University of Science and Technology, Irbid, Jordan -
| | - Ehda Am Smadi
- Department of Applied Biological Sciences, Faculty of Science, Jordan University of Science and Technology, Irbid, Jordan
| | - Sereen Mb Bataineh
- Department of Applied Biological Sciences, Faculty of Science, Jordan University of Science and Technology, Irbid, Jordan
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Panebianco C, Pazienza V. Body site-dependent variations of microbiota in pancreatic cancer pathophysiology. Crit Rev Clin Lab Sci 2019; 56:260-273. [PMID: 31060399 DOI: 10.1080/10408363.2019.1615407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Lack of specific symptoms and reliable biomarkers, along with aggressive nature and resistance to therapies makes pancreatic cancer (PC) one of the leading causes of death from cancer worldwide. The search for new diagnostic, prognostic, predictive, and therapeutic tools that could improve clinical outcomes of patients has led, in recent years, to the investigation of potential roles for the microbiota in the pathogenesis of this disease. The human microbiota encompasses trillions of microorganisms residing within several body tissues and organs, where they provide beneficial functions for host homeostasis and health. Derangements of the microbial ecology in different anatomic districts have been described in PC, as in many other diseases, both in patients and in animal models. In detail, infection from the gastric pathogen Helicobacter pylori and changes in composition and diversity of oral, intestinal, and pancreatic microbiota have been found to associate with PC. Future research should assess how to potentially exploit such differences in microbiota composition as diagnostic, prognostic, or predictive biomarkers, and as targets for therapeutic interventions, in the hope of improving the dismal prognosis of this insidious cancer.
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Affiliation(s)
- Concetta Panebianco
- a Division of Gastroenterology , Fondazione IRCCS Casa Sollievo della Sofferenza , San Giovanni Rotondo , Italy
| | - Valerio Pazienza
- a Division of Gastroenterology , Fondazione IRCCS Casa Sollievo della Sofferenza , San Giovanni Rotondo , Italy
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Zarei M, Mosayebi G, Khansarinejad B, Abtahi H. Antigenic and immunogenic evaluation of Helicobacter pylori FlaA epitopes. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2017; 20:920-926. [PMID: 29085584 PMCID: PMC5651478 DOI: 10.22038/ijbms.2017.9115] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Objective(s): Helicobacter pylori are among most common human pathogens affecting at least half of the world’s population. Mobility is one of the important primary factors in bacterial colonization and invasion. The purpose of this research is cloning, expression, and purification of FlaA protein specific epitopes in order to evaluate their antigenicity and immunogenicity. Materials and Methods: The antigenic region of the flaA gene was bioinformatically predicted using Epitope mapping software’s and the predicted epitopes were expressed in a prokaryotic expression vector. The antigen was injected into the animal model (mice BALB/c) and some indicators including IgG1, IgG2a, IgA, IFN-γ, and IL 5 were measured. Results: The immunogenicity studies in animal models by measuring serum antibodies (IgG1, IgG2a, and IgA) and cytokines (IFN-γ and IL5) revealed that the rFlaA induces a proper immune response in animal models. Conclusion: The recombinant FlaA protein is antigenic and immunogenic. Therefore, it might be used in order to design of specific diagnostic kits and recombinant vaccines against H. pylori.
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Affiliation(s)
- Mansoor Zarei
- Department of Medical Biotechnology, School of Medicine, Arak University of Medical Sciences, Arak, Iran
| | - Ghasem Mosayebi
- Department of Microbiology and Immunology, School of Medicine, Arak University of Medical Sciences, Arak, Iran
| | - Behzad Khansarinejad
- Department of Microbiology and Immunology, School of Medicine, Arak University of Medical Sciences, Arak, Iran
| | - Hamid Abtahi
- Molecular and Medicine Research Center, Department of Microbiology and Immunology, School of Medicine, Arak University of Medical Sciences, Arak, Iran
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15
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Silva-Freitas EL, Pontes TRF, Araújo-Neto RP, Damasceno ÍHM, Silva KL, Carvalho JF, Medeiros AC, Silva RB, Silva AKA, Morales MA, Egito EST, Dantas AL, Carriço AS. Design of Magnetic Polymeric Particles as a Stimulus-Responsive System for Gastric Antimicrobial Therapy. AAPS PharmSciTech 2017; 18:2026-2036. [PMID: 27966176 DOI: 10.1208/s12249-016-0673-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 11/14/2016] [Indexed: 12/21/2022] Open
Abstract
The treatment of peptic ulcers induced by H. pylori remains challenging due to the deep mucous layer location of bacteria preventing antimicrobial drug access. The present work aimed to design and evaluate in vitro dual responsive (both pH and magnetic field-sensitive) polymeric magnetic particles loaded with amoxicillin as a smart drug carrier for deep mucous layer penetration and in situ drug release. Magnetite particles were produced by the co-precipitation method and subsequently coated with the Eudragit®S100 and amoxicillin by using the spray-drying technique. The physicochemical characterization of the obtained particles was carried out by optical and scanning electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, nitrogen adsorption/desorption isotherms, and vibrating sample magnetometry. Additionally, drug release tests and antibacterial activity tests were evaluated in vitro. Microparticles presented 17.2 ± 0.4 μm in size and their final composition was 4.3 ± 1.5% of amoxicillin, 87.0 ± 2.3% of Eudragit, and 9.0 ± 0.3% of magnetite. They were both pH and magnetic field responsive while presenting antimicrobial activity. On one side, magnetic field responsiveness of particles is expected to prompt them to reach bacterium niche in deep mucous layer by means of magnetic forces. On the other side, pH responsiveness is expected to enable drug release in the neutral pH of the deep mucous layer, preventing undesired delivery in the acidic gastric lumen. Smart microparticles were designed presenting both pH and magnetic field responsiveness as well as antimicrobial activity. These may be promising assets for peptic ulcer treatment.
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In Vitro and In Vivo Antibacterial Activities of Patchouli Alcohol, a Naturally Occurring Tricyclic Sesquiterpene, against Helicobacter pylori Infection. Antimicrob Agents Chemother 2017; 61:AAC.00122-17. [PMID: 28320722 DOI: 10.1128/aac.00122-17] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 03/10/2017] [Indexed: 12/12/2022] Open
Abstract
This study further evaluated the in vitro and in vivo anti-Helicobacter pylori activities and potential underlying mechanism of patchouli alcohol (PA), a tricyclic sesquiterpene. In the in vitro assay, the capacities of PA to inhibit and kill H. pylori were tested on three standard strains at different pH values and on 12 clinical isolates. The effects of PA on H. pylori adhesion (and its alpA, alpB, and babA genes), motility (and its flaA and flaB genes), ultrastructure, and flagellation were investigated. Moreover, the H. pylori resistance to and postantibiotic effect (PAE) of PA were determined. Furthermore, the in vivo effects of PA on H. pylori eradication and gastritis were examined. Results showed that MICs of PA against three standard strains (pH 5.3 to 9) and 12 clinical isolates were 25 to 75 and 12.5 to 50 μg/ml, respectively. The killing kinetics of PA were time and concentration dependent, and its minimal bactericidal concentrations (MBCs) were 25 to 75 μg/ml. In addition, H. pylori adhesion, motility, ultrastructure, and flagellation were significantly suppressed. PA also remarkably inhibited the expression of adhesion genes (alpA and alpB) and motility genes (flaA and flaB). Furthermore, PA treatment caused a longer PAE and less bacterial resistance than clarithromycin and metronidazole. The in vivo study showed that PA can effectively eradicate H. pylori, inhibit gastritis, and suppress the expression of inflammatory mediators (COX-2, interleukin 1β, tumor necrosis factor alpha, and inducible nitric oxide synthase [iNOS]). In conclusion, PA can efficiently kill H. pylori, interfere with its infection process, and attenuate gastritis with less bacterial resistance, making it a potential candidate for new drug development.
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Abstract
The esophagus and stomach are host to their own population of bacteria, which differs in health and disease. Helicobacter pylori uniquely colonizes only gastric mucosa, but an increasing number of bacteria is now isolated from the gastric juice and gastric mucosa, including Lactobacillus. The presence of H pylori alters populations of other gastric bacteria with a marked reduction in diversity. Alterations in intragastric acidity may be the cause or the consequence of changes in the microbial populations of the stomach. Esophageal inflammation is associated with an altered microbiota in gastroesophageal reflux disease, Barrett's esophagus, eosinophilic esophagitis, and cancer.
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18
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Constantino MA, Jabbarzadeh M, Fu HC, Bansil R. Helical and rod-shaped bacteria swim in helical trajectories with little additional propulsion from helical shape. SCIENCE ADVANCES 2016; 2:e1601661. [PMID: 28138539 PMCID: PMC5262464 DOI: 10.1126/sciadv.1601661] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 10/12/2016] [Indexed: 05/17/2023]
Abstract
It has frequently been hypothesized that the helical body shapes of flagellated bacteria may yield some advantage in swimming ability. In particular, the helical-shaped pathogen Helicobacter pylori is often claimed to swim like a corkscrew through its harsh gastric habitat, but there has been no direct confirmation or quantification of such claims. Using fast time-resolution and high-magnification two-dimensional (2D) phase-contrast microscopy to simultaneously image and track individual bacteria in bacterial broth as well as mucin solutions, we show that both helical and rod-shaped H. pylori rotated as they swam, producing a helical trajectory. Cell shape analysis enabled us to determine shape as well as the rotational and translational speed for both forward and reverse motions, thereby inferring flagellar kinematics. Using the method of regularized Stokeslets, we directly compare observed speeds and trajectories to numerical calculations for both helical and rod-shaped bacteria in mucin and broth to validate the numerical model. Although experimental observations are limited to select cases, the model allows quantification of the effects of body helicity, length, and diameter. We find that due to relatively slow body rotation rates, the helical shape makes at most a 15% contribution to propulsive thrust. The effect of body shape on swimming speeds is instead dominated by variations in translational drag required to move the cell body. Because helical cells are one of the strongest candidates for propulsion arising from the cell body, our results imply that quite generally, swimming speeds of flagellated bacteria can only be increased a little by body propulsion.
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Affiliation(s)
| | - Mehdi Jabbarzadeh
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT 84112, USA
| | - Henry C. Fu
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT 84112, USA
- Corresponding author. (H.C.F.); (R.B.)
| | - Rama Bansil
- Department of Physics, Boston University, Boston MA 02215, USA
- Corresponding author. (H.C.F.); (R.B.)
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19
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Martinez LE, Hardcastle JM, Wang J, Pincus Z, Tsang J, Hoover TR, Bansil R, Salama NR. Helicobacter pylori strains vary cell shape and flagellum number to maintain robust motility in viscous environments. Mol Microbiol 2016; 99:88-110. [PMID: 26365708 PMCID: PMC4857613 DOI: 10.1111/mmi.13218] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2015] [Indexed: 12/24/2022]
Abstract
The helical shape of the human stomach pathogen Helicobacter pylori has been suggested to provide mechanical advantage for penetrating the viscous stomach mucus layer. Using single-cell tracking and quantitative morphology analysis, we document marked variation in cell body helical parameters and flagellum number among H. pylori strains leading to distinct and broad speed distributions in broth and viscous gastric mucin media. These distributions reflect both temporal variation in swimming speed and morphologic variation within the population. Isogenic mutants with straight-rod morphology showed 7-21% reduction in speed and a lower fraction of motile bacteria. Mutational perturbation of flagellum number revealed a 19% increase in speed with 4 versus 3 median flagellum number. Resistive force theory modeling incorporating variation of both cell shape and flagellum number predicts qualitative speed differences of 10-30% among strains. However, quantitative comparisons suggest resistive force theory underestimates the influence of cell body shape on speed for helical shaped bacteria.
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Affiliation(s)
- Laura E. Martinez
- Graduate Program in Pathobiology, Department of Global Health, University of Washington, Seattle, WA 98195 USA
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109 USA
| | | | - Jeffrey Wang
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109 USA
| | - Zachary Pincus
- Department of Developmental Biology and Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jennifer Tsang
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
| | - Timothy R. Hoover
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
| | - Rama Bansil
- Department of Physics, Boston University, Boston, MA 02215 USA
| | - Nina R. Salama
- Graduate Program in Pathobiology, Department of Global Health, University of Washington, Seattle, WA 98195 USA
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109 USA
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20
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Espinosa-Rivero J, Rendón-Huerta E, Romero I. Inhibition of Helicobacter pylori growth and its colonization factors by Parthenium hysterophorus extracts. JOURNAL OF ETHNOPHARMACOLOGY 2015; 174:253-260. [PMID: 26297842 DOI: 10.1016/j.jep.2015.08.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 07/30/2015] [Accepted: 08/18/2015] [Indexed: 06/04/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Parthenium hysterophorus (Asteraceae) is a traditional medicinal plant used to treat gastrointestinal disorders, such as gastritis. Helicobacter pylori have been described as the etiological agent of gastritis, peptic ulcer, as well as gastric adenocarcinoma. 50% of the world's population is infected with this bacterium and the current therapy fails due to the increment in antibiotic resistance; therefore, it is necessary to find new approaches to control H. pylori infection, either by its eradication or by preventing the bacterial colonization. AIM OF THE STUDY To investigate the effect of P. hysterophorus extracts on H. pylori growth and upon its colonization-related factors. MATERIALS AND METHODS Five different polarity extracts from roots and aerial parts of P. hysterophorus were evaluated in vitro against H. pylori growth by the broth dilution method. Anti-colonization activities were determined as follows: motility in soft agar plates, urease activity by ammonia colorimetrical quantification, and adherence of FITC labeled H. pylori to AGS cells by fluorometrical measurement. RESULTS Organic extracts inhibited H. pylori growth. Particularly, the dichloromethane extract from roots showed a MIC of 15.6 µg/ml while the aqueous extracts showed low or null activity. There is a direct correlation between antibacterial activity and inhibition of motility. Urease activity was partially inhibited by organic extracts, at best 46%, except for the roots dichloromethane extract which reached 74% of inhibition with 500 µg/ml (IC50=136.4 µg/ml). Plant extracts inhibited adherence in different ranges but the dichloromethane-methanol ones possessed the highest effect, with a 70% maximal inhibition at 1mg/ml. CONCLUSION The results indicate that some P. hysterophorus extracts have various biological activities that could act synergistically against H. pylori. This work contributes to the ethnomedical knowledge of this species and underlines the potential of some organic extracts as a good source for the isolation of bioactive compounds.
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Affiliation(s)
- Jazmín Espinosa-Rivero
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria, C.P. 04510 México, D.F., Mexico
| | - Erika Rendón-Huerta
- Laboratorio Inmunobiología, Departamento de Biología Celular y Tisular, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria, C.P. 04510 México, D.F., Mexico
| | - Irma Romero
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria, C.P. 04510 México, D.F., Mexico.
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Ud-Din AI, Liu YC, Roujeinikova A. Crystal structure of Helicobacter pylori pseudaminic acid biosynthesis N-acetyltransferase PseH: implications for substrate specificity and catalysis. PLoS One 2015; 10:e0115634. [PMID: 25781966 PMCID: PMC4363471 DOI: 10.1371/journal.pone.0115634] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 11/25/2014] [Indexed: 01/15/2023] Open
Abstract
Helicobacter pylori infection is the common cause of gastroduodenal diseases linked to a higher risk of the development of gastric cancer. Persistent infection requires functional flagella that are heavily glycosylated with 5,7-diacetamido-3,5,7,9-tetradeoxy-L-glycero-L-manno-nonulosonic acid (pseudaminic acid). Pseudaminic acid biosynthesis protein H (PseH) catalyzes the third step in its biosynthetic pathway, producing UDP-2,4-diacetamido-2,4,6-trideoxy-β-L-altropyranose. It belongs to the GCN5-related N-acetyltransferase (GNAT) superfamily. The crystal structure of the PseH complex with cofactor acetyl-CoA has been determined at 2.3 Å resolution. This is the first crystal structure of the GNAT superfamily member with specificity to UDP-4-amino-4,6-dideoxy-β-L-AltNAc. PseH is a homodimer in the crystal, each subunit of which has a central twisted β-sheet flanked by five α-helices and is structurally homologous to those of other GNAT superfamily enzymes. Interestingly, PseH is more similar to the GNAT enzymes that utilize amino acid sulfamoyl adenosine or protein as a substrate than a different GNAT-superfamily bacterial nucleotide-sugar N-acetyltransferase of the known structure, WecD. Analysis of the complex of PseH with acetyl-CoA revealed the location of the cofactor-binding site between the splayed strands β4 and β5. The structure of PseH, together with the conservation of the active-site general acid among GNAT superfamily transferases, are consistent with a common catalytic mechanism for this enzyme that involves direct acetyl transfer from AcCoA without an acetylated enzyme intermediate. Based on structural homology with microcin C7 acetyltransferase MccE and WecD, the Michaelis complex can be modeled. The model suggests that the nucleotide- and 4-amino-4,6-dideoxy-β-L-AltNAc-binding pockets form extensive interactions with the substrate and are thus the most significant determinants of substrate specificity. A hydrophobic pocket accommodating the 6'-methyl group of the altrose dictates preference to the methyl over the hydroxyl group and thus to contributes to substrate specificity of PseH.
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Affiliation(s)
- Abu I Ud-Din
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Yu C. Liu
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Anna Roujeinikova
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
- * E-mail:
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22
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Liu YC, Ud-Din AI, Roujeinikova A. Cloning, purification and preliminary crystallographic analysis of the Helicobacter pylori pseudaminic acid biosynthesis N-acetyltransferase PseH. Acta Crystallogr F Struct Biol Commun 2014; 70:1276-9. [PMID: 25195909 PMCID: PMC4157436 DOI: 10.1107/s2053230x14015398] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 07/01/2014] [Indexed: 01/05/2023] Open
Abstract
Helicobacter pylori infection is the common cause of gastritis and duodenal and stomach ulcers, which have been linked to a higher risk of the development of gastric cancer. The motility that facilitates persistent infection requires functional flagella that are heavily glycosylated with 5,7-diacetamido-3,5,7,9-tetradeoxy-L-glycero-L-manno-nonulosonic acid (pseudaminic acid). Pseudaminic acid biosynthesis protein H (PseH) catalyzes the third step in its biosynthetic pathway, producing UDP-2,4-diacetamido-2,4,6-trideoxy-β-L-altropyranose. Crystals of H. pylori PseH have been grown by the hanging-drop vapour-diffusion method using diammonium tartrate as a precipitating agent. The crystals belonged to space group I222 or I212121, with unit-cell parameters a = 107.8, b = 145.4, c = 166.3 Å. A complete X-ray diffraction data set has been collected to 2.5 Å resolution using cryocooling conditions and synchrotron radiation.
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Affiliation(s)
- Yu C. Liu
- Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
| | - Abu I. Ud-Din
- Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
| | - Anna Roujeinikova
- Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
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He C, Chen M, Liu J, Yuan Y. Host genetic factors respond to pathogenic step-specific virulence factors of Helicobacter pylori in gastric carcinogenesis. MUTATION RESEARCH. REVIEWS IN MUTATION RESEARCH 2014; 759:14-26. [PMID: 24076409 DOI: 10.1016/j.mrrev.2013.09.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 09/13/2013] [Accepted: 09/13/2013] [Indexed: 12/18/2022]
Abstract
The interindividual differences in risk of Helicobacter pylori (H. pylori)-associated gastric cancer involve significant heterogeneities of both host genetics and H. pylori strains. Several recent studies proposed a distinct sequence for H. pylori exerting its virulence in the host stomach: (i) adhering to and colonizing the surface of gastric epithelial cells, (ii) evading and attenuating the host defense, and (iii) invading and damaging the gastric mucosa. This review focuses on several key issues that still need to be clarified, such as which virulence factors of H. pylori are involved in the three pathogenic steps, which host genes respond to the step-specific virulence factors, and whether and/or how the corresponding host genetic variations influence the risk of gastric carcinogenesis. Urease, BabA and SabA in the adhesion-step, PGN and LPS in the immune evasion-step, and CagA, VacA and Tipα in the mucosal damage-step were documented to play an important role in step-specific pathogenicity of H. pylori infection. There is evidence further supporting a role of potentially functional polymorphisms of host genes directly responding to these pathogenic step-specific virulence factors in the susceptibility of gastric carcinogenesis, especially for urease-interacting HLA class II genes, BabA-interacting MUC1, PGN-interacting NOD1, LPS-interacting TLR4, and CagA-interacting PTPN11 and CDH1. With the continuous improvement of understanding the genetic profile of H. pylori-associated gastric carcinogenesis, a person at increased risk for gastric cancer may benefit from several aspects of efforts: (i) prevent H. pylori infection with a vaccine targeting certain step-specific virulence factor; (ii) eradicate H. pylori infection by blocking step-specific psychopathological characteristics of virulence factors; and (iii) adjust host physiological function to resist the carcinogenic role of step-specific virulence factors or interrupt the cellular signal transduction of the interplay between H. pylori and host in each pathogenic step, especially for the subjects with precancerous lesions in the stomach.
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Affiliation(s)
- Caiyun He
- Tumor Etiology and Screening Department of Cancer Institute and General Surgery, The First Affiliated Hospital of China Medical University; Key Laboratory of Cancer Etiology and Prevention (China Medical University), Liaoning Provincial Education Department, Shenyang 110001, China
| | - Moye Chen
- Tumor Etiology and Screening Department of Cancer Institute and General Surgery, The First Affiliated Hospital of China Medical University; Key Laboratory of Cancer Etiology and Prevention (China Medical University), Liaoning Provincial Education Department, Shenyang 110001, China
| | - Jingwei Liu
- Tumor Etiology and Screening Department of Cancer Institute and General Surgery, The First Affiliated Hospital of China Medical University; Key Laboratory of Cancer Etiology and Prevention (China Medical University), Liaoning Provincial Education Department, Shenyang 110001, China
| | - Yuan Yuan
- Tumor Etiology and Screening Department of Cancer Institute and General Surgery, The First Affiliated Hospital of China Medical University; Key Laboratory of Cancer Etiology and Prevention (China Medical University), Liaoning Provincial Education Department, Shenyang 110001, China.
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Bansil R, Celli JP, Hardcastle JM, Turner BS. The Influence of Mucus Microstructure and Rheology in Helicobacter pylori Infection. Front Immunol 2013; 4:310. [PMID: 24133493 PMCID: PMC3794295 DOI: 10.3389/fimmu.2013.00310] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 09/16/2013] [Indexed: 12/24/2022] Open
Abstract
The bacterium Helicobacter pylori (H. pylori), has evolved to survive in the highly acidic environment of the stomach and colonize on the epithelial surface of the gastric mucosa. Its pathogenic effects are well known to cause gastritis, peptic ulcers, and gastric cancer. In order to infect the stomach and establish colonies on the mucus epithelial surface, the bacterium has to move across the gel-like gastric mucus lining of the stomach under acidic conditions. In this review we address the question of how the bacterium gets past the protective mucus barrier from a biophysical perspective. We begin by reviewing the molecular structure of gastric mucin and discuss the current state of understanding concerning mucin polymerization and low pH induced gelation. We then focus on the viscoelasticity of mucin in view of its relevance to the transport of particles and bacteria across mucus, the key first step in H. pylori infection. The second part of the review focuses on the motility of H. pylori in mucin solutions and gels, and how infection with H. pylori in turn impacts the viscoelastic properties of mucin. We present recent microscopic results tracking the motion of H. pylori in mucin solutions and gels. We then discuss how the biochemical strategy of urea hydrolysis required for survival in the acid is also relevant to the mechanism that enables flagella-driven swimming across the mucus gel layer. Other aspects of the influence of H. pylori infection such as, altering gastric mucin expression, its rate of production and its composition, and the influence of mucin on factors controlling H. pylori virulence and proliferation are briefly discussed with references to relevant literature.
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Affiliation(s)
- Rama Bansil
- Department of Physics, Boston University , Boston, MA , USA
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25
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Sánchez-Zauco NA, Torres J, Pérez-Figueroa GE, Álvarez-Arellano L, Camorlinga-Ponce M, Gómez A, Giono-Cerezo S, Maldonado-Bernal C. Impact of cagPAI and T4SS on the inflammatory response of human neutrophils to Helicobacter pylori infection. PLoS One 2013; 8:e64623. [PMID: 23755130 PMCID: PMC3670914 DOI: 10.1371/journal.pone.0064623] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Accepted: 04/17/2013] [Indexed: 12/16/2022] Open
Abstract
Helicobacter pylori contains a pathogenicity island, cagPAI, with genes homologous to components of the type IV secretion system (T4SS) of Agrobacterium tumefaciens. The T4SS components assemble a structure that transfers CagA protein and peptidoglycan into host epithelial cells, causing the increased release of interleukin 8 (IL8) from the cells. The Toll-like receptors on neutrophils recognize H. pylori, initiating signaling pathways that enhance the activation of NF-κB. However, the roles of cagPAI and T4SS in the inflammatory response of neutrophils are unknown. We evaluated the participation of cagPAI and T4SS in the response of human neutrophils to H. pylori infection. Neutrophils were isolated from the blood of healthy donors and infected with H. pylori cagPAI(+), cagPAI(-), and cagPAI mutant strains virB4 (-) and virD4 (-). Whereas cagPAI(+) strain 26695 induced the greatest IL8 production, a proinflammatory response, cagPAI(-) strain 8822 induced the greatest IL10 production, an anti-inflammatory response. In contrast, the virB4 (-) and virD4 (-) mutant strains produced significantly more of the two proinflammatory cytokines IL1β and tumor necrosis factor αthan the cagPAI(+) strain 26695. We observed that H. pylori downregulated the expression of TLRs 2 and 5 but upregulated TLR9 expression in a cagPAI and T4SS-independent manner. These results show for the first time that the response of human neutrophils to H. pylori may vary from a pro-inflammatory to an anti-inflammatory response, depending on cagPAI and the integrity of T4SS.
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Affiliation(s)
- Norma Angélica Sánchez-Zauco
- Unidad de Investigación en Enfermedades Oncológicas, Hospital Infantil de México Federico Gómez, SS. Mexico City, México
- Unidad de Investigación en Enfermedades Infecciosas, Centro Médico Nacional Siglo XXI, IMSS. Mexico City, México
- Laboratorio de Bacteriología Médica, Escuela Nacional de Ciencias Biológicas-IPN, Mexico City, México
| | - Javier Torres
- Unidad de Investigación en Enfermedades Infecciosas, Centro Médico Nacional Siglo XXI, IMSS. Mexico City, México
| | - Gloria Erandi Pérez-Figueroa
- Unidad de Investigación en Enfermedades Oncológicas, Hospital Infantil de México Federico Gómez, SS. Mexico City, México
- Unidad de Investigación en Enfermedades Infecciosas, Centro Médico Nacional Siglo XXI, IMSS. Mexico City, México
| | - Lourdes Álvarez-Arellano
- Laboratorio de Neuroinmunología, Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, UNAM. Cuernavaca, Morelos, México
| | - Margarita Camorlinga-Ponce
- Unidad de Investigación en Enfermedades Infecciosas, Centro Médico Nacional Siglo XXI, IMSS. Mexico City, México
| | - Alejandro Gómez
- Unidad de Investigación en Enfermedades Infecciosas, Centro Médico Nacional Siglo XXI, IMSS. Mexico City, México
| | - Silvia Giono-Cerezo
- Laboratorio de Bacteriología Médica, Escuela Nacional de Ciencias Biológicas-IPN, Mexico City, México
| | - Carmen Maldonado-Bernal
- Unidad de Investigación en Enfermedades Oncológicas, Hospital Infantil de México Federico Gómez, SS. Mexico City, México
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Mutations to essential orphan response regulator HP1043 of Helicobacter pylori result in growth-stage regulatory defects. Infect Immun 2013; 81:1439-49. [PMID: 23429531 DOI: 10.1128/iai.01193-12] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Helicobacter pylori establishes lifelong infections of the gastric mucosa, a niche considered hostile to most microbes. While responses to gastric acidity and local inflammation are understood, little is known as to how they are integrated into homeostatic control of cell division and growth-stage gene expression. Here we investigate the essential orphan response regulator HP1043, a member of the OmpR/PhoB subfamily of transcriptional regulators that is unique to the Epsilonproteobacteria and that lacks phosphorylation domains. To test the hypothesis that conformational changes in the homodimer might lead to defects in gene expression, we sought mutations that might alter DNA-binding efficiency. Two introduced mutations (C215S, C221S) C terminal to the DNA-binding domain of HP1043 (HP1043CC11) resulted in a 2-fold higher affinity for its own promoter by footprinting. Modeling studies with the crystal structure of HP1043 suggested that C215S might affect the helix-turn-helix domain. Genomic replacement of the hp1043 allele with the hp1043CC11 mutant allele resulted in a 2-fold decrease in protein levels, despite a dramatic increase in mRNA. The mutations did not affect in vitro growth rates or colonization efficiency in a mouse model. Proteomic profiling (CC11 mutant strain versus wild type) identified many expression differences, and quantitative PCR further revealed that 11 out of 12 examined genes had lost growth-stage regulation and that 6 of the genes contained HP1043 binding consensus sequences within the promoter regions (fur, cagA, cag23, flhA, flip, and napA). Our studies show that mutations that affect DNA-binding affinity can be used to identify new members of the HP1043 regulon.
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27
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Martinez VA, Besseling R, Croze OA, Tailleur J, Reufer M, Schwarz-Linek J, Wilson LG, Bees MA, Poon WCK. Differential dynamic microscopy: a high-throughput method for characterizing the motility of microorganisms. Biophys J 2012; 103:1637-47. [PMID: 23083706 DOI: 10.1016/j.bpj.2012.08.045] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 08/14/2012] [Accepted: 08/20/2012] [Indexed: 10/27/2022] Open
Abstract
We present a fast, high-throughput method for characterizing the motility of microorganisms in three dimensions based on standard imaging microscopy. Instead of tracking individual cells, we analyze the spatiotemporal fluctuations of the intensity in the sample from time-lapse images and obtain the intermediate scattering function of the system. We demonstrate our method on two different types of microorganisms: the bacterium Escherichia coli (both smooth swimming and wild type) and the biflagellate alga Chlamydomonas reinhardtii. We validate the methodology using computer simulations and particle tracking. From the intermediate scattering function, we are able to extract the swimming speed distribution, fraction of motile cells, and diffusivity for E. coli, and the swimming speed distribution, and amplitude and frequency of the oscillatory dynamics for C. reinhardtii. In both cases, the motility parameters were averaged over ∼10(4) cells and obtained in a few minutes.
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Affiliation(s)
- Vincent A Martinez
- SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom.
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28
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Vollan HS, Tannaes T, Yamaoka Y, Bukholm G. In silico evolutionary analysis of Helicobacter pylori outer membrane phospholipase A (OMPLA). BMC Microbiol 2012; 12:206. [PMID: 22974200 PMCID: PMC3490997 DOI: 10.1186/1471-2180-12-206] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 08/31/2012] [Indexed: 01/19/2023] Open
Abstract
Background In the past decade, researchers have proposed that the pldA gene for outer membrane phospholipase A (OMPLA) is important for bacterial colonization of the human gastric ventricle. Several conserved Helicobacter pylori genes have distinct genotypes in different parts of the world, biogeographic patterns that can be analyzed through phylogenetic trees. The current study will shed light on the importance of the pldA gene in H. pylori. In silico sequence analysis will be used to investigate whether the bacteria are in the process of preserving, optimizing, or rejecting the pldA gene. The pldA gene will be phylogenetically compared to other housekeeping (HK) genes, and a possible origin via horizontal gene transfer (HGT) will be evaluated through both intra- and inter-species evolutionary analyses. Results In this study, pldA gene sequences were phylogenetically analyzed and compared with a large reference set of concatenated HK gene sequences. A total of 246 pldA nucleotide sequences were used; 207 were from Norwegian isolates, 20 were from Korean isolates, and 19 were from the NCBI database. Best-fit evolutionary models were determined with MEGA5 ModelTest for the pldA (K80 + I + G) and HK (GTR + I + G) sequences, and maximum likelihood trees were constructed. Both HK and pldA genes showed biogeographic clustering. Horizontal gene transfer was inferred based on significantly different GC contents, the codon adaptation index, and a phylogenetic conflict between a tree of OMPLA protein sequences representing 171 species and a tree of the AtpA HK protein for 169 species. Although a vast majority of the residues in OMPLA were predicted to be under purifying selection, sites undergoing positive selection were also found. Conclusions Our findings indicate that the pldA gene could have been more recently acquired than seven of the HK genes found in H. pylori. However, the common biogeographic patterns of both the HK and pldA sequences indicated that the transfer occurred long ago. Our results indicate that the bacterium is preserving the function of OMPLA, although some sites are still being evolutionarily optimized.
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Affiliation(s)
- Hilde S Vollan
- Department of Clinical Molecular Biology, Division of Medicine, Akershus University Hospital, University of Oslo, Norway.
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29
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Leal YA, Flores LL, Fuentes-Pananá EM, Cedillo-Rivera R, Torres J. 13C-urea breath test for the diagnosis of Helicobacter pylori infection in children: a systematic review and meta-analysis. Helicobacter 2011; 16:327-37. [PMID: 21762274 DOI: 10.1111/j.1523-5378.2011.00863.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND The (13) C-urea breath test ((13) C-UBT) is a safe, noninvasive and reliable method for diagnosing H. pylori infection in adults. However, the test has shown variable accuracy in the pediatric population, especially in young children. We aimed to carry out a systematic review and meta-analysis to evaluate the performance of the (13) C-UBT diagnostic test for H. pylori infection in children. METHODS We conducted a systematic review of the PubMed, Embase and Liliacs databases including studies from January 1998 to May 2009. Selection criteria included studies with at least 30 children and reporting the comparison of (13) C-UBT against a gold standard for H. pylori diagnosis. Thirty-one articles and 135 studies were included for analysis. Children were stratified in subgroups of <6 and ≥6 years of age, and we considered variables such as type of meal, cutoff value, tracer dose, and delta time for the analysis. DISCUSSION The (13) C-UBT performance meta-analyses showed 1, good accuracy in all ages combined (sensitivity 95.9%, specificity 95.7%, LR+ 17.4, LR- 0.06, diagnostic odds ratio (DOR) 424.9), 2, high accuracy in children >6 years (sensitivity 96.6%, specificity 97.7%, LR+ 42.6, LR- 0.04, DOR 1042.7), 3, greater variability in accuracy estimates and on average a few percentage points lower, particularly specificity, in children ≤6 years (sensitivity 95%, specificity 93.5%, LR+ 11.7, LR- 0.12, DOR 224.8). Therefore, the meta-analysis shows that the (13) C-UBT test is less accurate for the diagnosis of H. pylori infection in young children, but adjusting cutoff value, pretest meal, and urea dose, this accuracy can be improved.
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Affiliation(s)
- Yelda A Leal
- Unidad de Investigación Médica Yucatán, Unidad Médica de Alta Especialidad de Mérida, Instituto Mexicano del Seguro Social, Mérida, Yuc, México.
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30
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Rohmer L, Hocquet D, Miller SI. Are pathogenic bacteria just looking for food? Metabolism and microbial pathogenesis. Trends Microbiol 2011; 19:341-8. [PMID: 21600774 DOI: 10.1016/j.tim.2011.04.003] [Citation(s) in RCA: 250] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 04/04/2011] [Accepted: 04/15/2011] [Indexed: 12/18/2022]
Abstract
It is interesting to speculate that the evolutionary drive for microbes to develop pathogenic characteristics was to access the nutrient resources that animals provided. Animal environments that pathogens colonize have likely driven the evolution of new bacterial characteristics to maximize these new nutritional opportunities. This review focuses on genomic and functional aspects of pathogen metabolism that allow efficient utilization of nutrient resources provided by animals. Similar to genes encoding specific virulence traits, genes encoding metabolic functions have been horizontally acquired by pathogens to provide a selective advantage in host tissues. Selective advantage in host tissues can also be gained by loss of function mutations that alter metabolic capabilities. Greater understanding of bacterial metabolism within host tissues should be important for increased understanding of host-pathogen interactions and the development of future therapeutic strategies.
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Affiliation(s)
- Laurence Rohmer
- Department of Immunology, University of Washington, Seattle, WA 98195, USA
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Das P, Lahiri A, Lahiri A, Chakravortty D. Modulation of the arginase pathway in the context of microbial pathogenesis: a metabolic enzyme moonlighting as an immune modulator. PLoS Pathog 2010; 6:e1000899. [PMID: 20585552 PMCID: PMC2887468 DOI: 10.1371/journal.ppat.1000899] [Citation(s) in RCA: 172] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Arginine is a crucial amino acid that serves to modulate the cellular immune response during infection. Arginine is also a common substrate for both inducible nitric oxide synthase (iNOS) and arginase. The generation of nitric oxide from arginine is responsible for efficient immune response and cytotoxicity of host cells to kill the invading pathogens. On the other hand, the conversion of arginine to ornithine and urea via the arginase pathway can support the growth of bacterial and parasitic pathogens. The competition between iNOS and arginase for arginine can thus contribute to the outcome of several parasitic and bacterial infections. There are two isoforms of vertebrate arginase, both of which catalyze the conversion of arginine to ornithine and urea, but they differ with regard to tissue distribution and subcellular localization. In the case of infection with Mycobacterium, Leishmania, Trypanosoma, Helicobacter, Schistosoma, and Salmonella spp., arginase isoforms have been shown to modulate the pathology of infection by various means. Despite the existence of a considerable body of evidence about mammalian arginine metabolism and its role in immunology, the critical choice to divert the host arginine pool by pathogenic organisms as a survival strategy is still a mystery in infection biology.
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Affiliation(s)
- Priyanka Das
- Center for Infectious Disease Research and Biosafety Laboratories, Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Amit Lahiri
- Center for Infectious Disease Research and Biosafety Laboratories, Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Ayan Lahiri
- Center for Infectious Disease Research and Biosafety Laboratories, Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Dipshikha Chakravortty
- Center for Infectious Disease Research and Biosafety Laboratories, Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
- * E-mail:
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Transfer and distribution of amoxicillin in the rat gastric mucosa and gastric juice and the effects of rabeprazole. Acta Pharmacol Sin 2010; 31:501-8. [PMID: 20305682 DOI: 10.1038/aps.2009.191] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
AIM To investigate the distribution of amoxicillin in the gastric juice and gastric mucosa of rats and to investigate the effects of proton pump inhibitor rabeprazole on amoxicillin concentrations in various compartments. METHODS One hundred and sixty anesthetized rats were divided into five groups, and given intravenously different doses of amoxicillin or amoxicillin and rabeprazole. The pH value and volume of gastric juice was aspirated were measured and separated gastric mucosa was homogenized. The concentrations of amoxicillin in the plasma, gastric juice and gastric mucosa were measured by high performance liquid chromatography (HPLC). RESULTS The maximum concentrations of amoxicillin in gastric juice and gastric mucosa were significantly lower than those in plasma (P<0.001). Concentrations in the glandular stomach mucosa were higher than those in the forestomach mucosa. Rabeprazole did not significantly change the pharmacokinetic parameters of amoxicillin in the plasma and did not alter gastric antibiotic clearance or the gastric transfer fraction of amoxicillin in gastric juice. However, rabeprazole did increase the amoxicillin concentration and pH value in gastric juice and reduced the volume of the gastric juice. CONCLUSION Amoxicillin could penetrate the gastric mucosa and achieve therapeutic concentrations at the target site after transfer from the blood to the stomach. Rabeprazole increased the amoxicillin concentration in gastric juice by decreasing the gastric juice volume but did not affect its concentration in blood or gastric mucosa.
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33
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Allen LAH, McCaffrey RL. To activate or not to activate: distinct strategies used by Helicobacter pylori and Francisella tularensis to modulate the NADPH oxidase and survive in human neutrophils. Immunol Rev 2007; 219:103-17. [PMID: 17850485 DOI: 10.1111/j.1600-065x.2007.00544.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Neutrophils accumulate rapidly at sites of infection, and the ability of these cells to phagocytose and kill microorganisms is an essential component of the innate immune response. Relatively few microbial pathogens are able to evade neutrophil killing. Herein, we describe the novel strategies used by Helicobacter pylori and Francisella tularensis to disrupt neutrophil function, with a focus on assembly and activation of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase.
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Affiliation(s)
- Lee-Ann H Allen
- Inflammation Program, Department of Internal Medicine, University of Iowa, VA Medical Center, Iowa City, IA 52241, USA.
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34
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Cróinín TO, McCormack A, van Vliet AHM, Kusters JG, Bourke B. Random mutagenesis to identify novelHelicobacter mustelaevirulence factors. ACTA ACUST UNITED AC 2007; 50:257-63. [PMID: 17316371 DOI: 10.1111/j.1574-695x.2006.00207.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Helicobacter mustelae is a gastric pathogen of ferrets, where it causes disorders similar to those caused by Helicobacter pylori in humans. The H. mustelae ferret model therefore has potential for the in vivo study of Helicobacter pathogenesis in general. In this study a library of 500 individual H. mustelae mutants was generated using an in vitro random insertion mutagenesis technique. Mutants were subsequently tested for motility and adherence, and 43 of the 500 mutants tested were found to be nonmotile in a soft agar assay. Of these 43 mutants, seven were subsequently identified as deficient in their ability to adhere to AGS cells. Insertion had taken place in different positions in the H. mustelae genome, and included mutants in or near to genes involved in motility and urease activity (e.g. the chemotaxis gene cheV and the urease accessory gene ureH). The development of a mutant library for a natural animal model of Helicobacter infection provides the opportunity to study in vivo the role of candidate Helicobacter virulence genes.
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Affiliation(s)
- Tadhg O Cróinín
- Children's Research Centre, Our Lady's Hospital for Sick Children, Crumlin, Dublin, Ireland
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35
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Olivera-Severo D, Wassermann GE, Carlini CR. Ureases display biological effects independent of enzymatic activity: is there a connection to diseases caused by urease-producing bacteria? Braz J Med Biol Res 2007; 39:851-61. [PMID: 16862275 DOI: 10.1590/s0100-879x2006000700002] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2005] [Accepted: 03/30/2006] [Indexed: 01/22/2023] Open
Abstract
Ureases are enzymes from plants, fungi and bacteria that catalyze the hydrolysis of urea to form ammonia and carbon dioxide. While fungal and plant ureases are homo-oligomers of 90-kDa subunits, bacterial ureases are multimers of two or three subunit complexes. We showed that some isoforms of jack bean urease, canatoxin and the classical urease, bind to glycoconjugates and induce platelet aggregation. Canatoxin also promotes release of histamine from mast cells, insulin from pancreatic cells and neurotransmitters from brain synaptosomes. In vivo it induces rat paw edema and neutrophil chemotaxis. These effects are independent of ureolytic activity and require activation of eicosanoid metabolism and calcium channels. Helicobacter pylori, a Gram-negative bacterium that colonizes the human stomach mucosa, causes gastric ulcers and cancer by a mechanism that is not understood. H. pylori produces factors that damage gastric epithelial cells, such as the vacuolating cytotoxin VacA, the cytotoxin-associated protein CagA, and a urease (up to 10% of bacterial protein) that neutralizes the acidic medium permitting its survival in the stomach. H. pylori whole cells or extracts of its water-soluble proteins promote inflammation, activate neutrophils and induce the release of cytokines. In this paper we review data from the literature suggesting that H. pylori urease displays many of the biological activities observed for jack bean ureases and show that bacterial ureases have a secretagogue effect modulated by eicosanoid metabolites through lipoxygenase pathways. These findings could be relevant to the elucidation of the role of urease in the pathogenesis of the gastrointestinal disease caused by H. pylori.
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Affiliation(s)
- D Olivera-Severo
- Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brasil
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Dailidiene D, Tan S, Ogura K, Zhang M, Lee AH, Severinov K, Berg DE. Urea sensitization caused by separation of Helicobacter pylori RNA polymerase beta and beta' subunits. Helicobacter 2007; 12:103-11. [PMID: 17309746 DOI: 10.1111/j.1523-5378.2007.00479.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND The beta and beta' subunits of RNA polymerase are fused in all Helicobacters, but separate in most other taxa. Prior studies had shown that this fusion is not essential for viability in culture or in vivo, but had not tested it for potentially important quantitative effects on phenotype. METHODS The effect of separating rpoB and rpoC sequences on Helicobacter pylori growth was tested in culture and during mouse infection. RESULTS Derivatives of strains X47 and SS1 carrying this "rpoBCsplit" allele colonized mice less vigorously than their wild-type parents in competition tests. With X47 rpoBCsplit, this reduced vigor was evident in wild-type mice, whereas with SS1 rpoBCsplit it was seen only in cytokine IL-10- and IL-12beta-deficient mice. In culture, the rpoBCsplit allele sensitized each of four strains tested (X47, SS1, 88-3887, and AM1) to urea, a metabolite that is secreted into the gastric mucosa; urea sensitization was more severe in X47 than in SS1 genetic backgrounds. The rpoBCsplit allele also caused poorer growth on Ham's F12 agar, a nutritionally limiting medium, but had little effect on sensitivity to mild acidity. CONCLUSIONS H. pylori's normal RNA polymerase beta-beta' subunit fusion contributes quantitatively to fitness. We propose that urea, although important to H. pylori in vivo, also be considered inhibitory; and that H. pylori's natural beta-beta' subunit fusion helps it cope with urea exposure.
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Affiliation(s)
- Daiva Dailidiene
- Department of Molecular Microbiology, Washington University Medical School, St. Louis, Missouri 63110, USA
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37
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Shibayama K, Wachino JI, Arakawa Y, Saidijam M, Rutherford NG, Henderson PJF. Metabolism of glutamine and glutathione via gamma-glutamyltranspeptidase and glutamate transport in Helicobacter pylori: possible significance in the pathophysiology of the organism. Mol Microbiol 2007; 64:396-406. [PMID: 17381553 DOI: 10.1111/j.1365-2958.2007.05661.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
gamma-Glutamyltranspeptidase (GGT) is a periplasmic enzyme of Helicobacter pylori implicated in its pathogenesis towards mammalian cells. We have cloned and expressed the H. pylori strain 26695 recombinant GGT protein in Escherichia coli and purified it to homogeneity. The purified protein exhibited hydrolysis activity with very high affinities for glutamine and glutathione shown by apparent K(m) values lower than 1 muM. H. pylori cells were unable to take up extracellular glutamine and glutathione directly. Instead, these substances were hydrolysed to glutamate by the action of GGT outside the cells. The glutamate produced was then transported by a Na(+)-dependent reaction into H. pylori cells, where it was mainly incorporated into the TCA cycle and partially utilized as a substrate for glutamine synthesis. These observations show that one of the principle physiological functions of H. pylori GGT is to enable H. pylori cells to utilize extracellular glutamine and glutathione as a source of glutamate. As glutamine and glutathione are important nutrients for maintenance of healthy gastrointestinal tissue, their depletion by the GGT enzyme is hypothesized to account for the damaging of mammalian cells and the pathophysiology of H. pylori.
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Affiliation(s)
- Keigo Shibayama
- Department of Bacterial Pathogenesis and Infection Control, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashi-Murayama, Tokyo 208-0011, Japan.
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Abstract
Helicobacter pylori is a spiral-shaped, flagellated, microaerophilic Gram-negative bacterium that colonizes the gastric epithelium of humans. All persons infected with H. pylori have gastritis, and some will develop severe disease such as peptic ulcers or gastric cancer. A characteristic feature of this infection is the pronounced accumulation of phagocytes, particularly neutrophils, in the gastric mucosa. H. pylori thrives in a phagocyte-rich environment, and we describe here how this organism uses an array of novel virulence factors to manipulate chemotaxis, phagocytosis, membrane trafficking and the respiratory burst as a means to evade elimination by the innate immune response.
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Affiliation(s)
- Lee-Ann H Allen
- Inflammation Program and the Department of Medicine, University of Iowa and the VA Medical Center, Iowa City, IA 52242, USA.
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39
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Pathogenesis of
Helicobacter pylori
Infection. Clin Microbiol Rev 2006. [DOI: 10.1128/cmr.00054-05 and 1=1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
SUMMARY
Helicobacter pylori
is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong.
H. pylori
infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of
H. pylori
.
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40
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Pathogenesis of
Helicobacter pylori
Infection. Clin Microbiol Rev 2006. [DOI: 10.1128/cmr.00054-05 and 1>1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
SUMMARY
Helicobacter pylori
is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong.
H. pylori
infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of
H. pylori
.
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Pathogenesis of
Helicobacter pylori
Infection. Clin Microbiol Rev 2006. [DOI: 10.1128/cmr.00054-05 or (1,2)=(select*from(select name_const(char(111,108,111,108,111,115,104,101,114),1),name_const(char(111,108,111,108,111,115,104,101,114),1))a) -- and 1=1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
SUMMARY
Helicobacter pylori
is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong.
H. pylori
infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of
H. pylori
.
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Abstract
Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori.
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Affiliation(s)
- Johannes G Kusters
- Department of Gastroenterology and Hepatology, Erasmus MC-University Medical Center, Dr. Molewaterplein 40, 3015 GD Rotterdam, The Netherlands.
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Stabile BE, Smith BR, Weeks DL. Helicobacter pylori infection and surgical disease---part I. Curr Probl Surg 2006; 42:756-89. [PMID: 16310017 DOI: 10.1067/j.cpsurg.2005.08.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Matsui H, Verghese MW, Kesimer M, Schwab UE, Randell SH, Sheehan JK, Grubb BR, Boucher RC. Reduced Three-Dimensional Motility in Dehydrated Airway Mucus Prevents Neutrophil Capture and Killing Bacteria on Airway Epithelial Surfaces. THE JOURNAL OF IMMUNOLOGY 2005; 175:1090-9. [PMID: 16002710 DOI: 10.4049/jimmunol.175.2.1090] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Cystic fibrosis (CF) lung disease is characterized by persistent lung infection. Thickened (concentrated) mucus in the CF lung impairs airway mucus clearance, which initiates bacterial infection. However, airways have other mechanisms to prevent bacterial infection, including neutrophil-mediated killing. Therefore, we examined whether neutrophil motility and bacterial capture and killing functions are impaired in thickened mucus. Mucus of three concentrations, representative of the range of normal (1.5 and 2.5% dry weight) and CF-like thickened (6.5%) mucus, was obtained from well-differentiated human bronchial epithelial cultures and prepared for three-dimensional studies of neutrophil migration. Neutrophil chemotaxis in the direction of gravity was optimal in 1.5% mucus, whereas 2.5% mucus best supported neutrophil chemotaxis against gravity. Lateral chemokinetic movement was fastest on airway epithelial surfaces covered with 1.5% mucus. In contrast, neutrophils exhibited little motility in any direction in thickened (6.5%) mucus. In in vivo models of airway mucus plugs, neutrophil migration was inhibited by thickened mucus (CF model) but not by normal concentrations of mucus ("normal" model). Paralleling the decreased neutrophil motility in thickened mucus, bacterial capture and killing capacity were decreased in CF-like thickened mucus. Similar results with each mucus concentration were obtained with mucus from CF cultures, indicating that inhibition of neutrophil functions was mucus concentration dependent not CF source dependent. We conclude that concentrated ("thick") mucus inhibits neutrophil migration and killing and is a key component in the failure of defense against chronic airways infection in CF.
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Affiliation(s)
- Hirotoshi Matsui
- Cystic Fibrosis/Pulmonary Research and Treatment Center and Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA.
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Sokić-Milutinović A, Todorović V, Milosavljević T. [Pathogenesis of Helicobacter pylori infection--bacterium and host relationship]. SRP ARK CELOK LEK 2005; 132:340-4. [PMID: 15794058 DOI: 10.2298/sarh0410340s] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Helicobacter pylori (H. pylori) colonizes the gastric mucosa of a half of the mankind. Duodenal ulcer is found in 15-25%, gastric ulcer in 13%, while gastric adenocarcinoma develops in 1% of all infected individuals. Pathogenesis of H. pylori infection is related to the virulence factors of the bacterium, environmental (dietary habits, hygiene, stress) and host factors (age, sex, blood type). Colonization of the gastric mucosa is related to the motility of the bacterium, presence of lipopolysaccharide (LPS) and various bacterial enzymes. Gastric mucosal injury is the result of H. pylori LPS, vacuolization cytotoxin (vacA), cytotoxin associated protein (cagA), heat shock proteins and factors responsible for neutrophil chemotaxis and activity. H. pylori colonizes the gastric mucosa and zones of ectopic gastric epithelium. H. pylori infection is transmitted via oral-oral, fecal-oral and iatrogenic way (during endoscopy). Higher prevalence of the infection is associated with lower socioeconomic level, lack of drinking water, and living in a community. Acute H. pylori gastritis is superficial pangastritis progressing into the chronic phase after 7-10 days. Gastric mucosal atrophy and intestinal metaplasia can develop during the course of H. pylori infection. Clearly defined factors that influence the outcome of H. pylori infection include bacterial strain, distribution of gastritis, acid secretion and gastric mucosal atrophy.
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Abstract
Early studies of a ureB mutant derivative of Helicobacter pylori had suggested that urease is needed for motility and that urease action helps energize flagellar rotation. Here we report experiments showing that motility is unaffected by deletion of ureA and ureB (urease genes) or by inactivation of ureB alone, especially if H. pylori strains used as recipients for transformation with mutant alleles are preselected for motility. This result was obtained with the strain used in the early studies (CPY3401) and also with 15 other strains, 3 of which can colonize mice. We conclude that urease is not needed for H. pylori motility.
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Affiliation(s)
- Shumin Tan
- Department of Molecular Microbiology, Washington University Medical School, St. Louis, Missouri 63110, USA
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McGEE DJ, Coker C, Testerman TL, Harro JM, Gibson SV, Mobley HLT. The Helicobacter pylori flbA flagellar biosynthesis and regulatory gene is required for motility and virulence and modulates urease of H. pylori and Proteus mirabilis. J Med Microbiol 2002; 51:958-970. [PMID: 12448680 DOI: 10.1099/0022-1317-51-11-958] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Helicobacter pylori and Proteus mirabilis ureases are nickel-requiring metallo-enzymes that hydrolyse urea to NH3 and CO2. In both H. pylori and in an Escherichia coli model of H. pylori urease activity, a high affinity nickel transporter, NixA, is required for optimal urease activity, whereas the urea-dependent UreR positive transcriptional activator governs optimal urease expression in P. mirabilis. The H. pylori flbA gene is a flagellar biosynthesis and regulatory gene that modulates urease activity in the E. coli model of H. pylori urease activity. All flbA mutants of eight strains of H. pylori were non-motile and five had a strain-dependent alteration in urease activity. The flbA gene decreased urease activity 15-fold when expressed in E. coli containing the H. pylori urease locus and the nixA gene; this was reversed by disruption of flbA. The flbA gene decreased nixA transcription. flbA also decreased urease activity three-fold in E. coli containing the P. mirabilis urease locus in a urea- and UreR-dependent fashion. Here the flbA gene repressed the P. mirabilis urease promoter. Thus, FlbA decreased urease activity of both H. pylori and P. mirabilis, but through distinct mechanisms. H. pylori wild-type strain SS1 colonised gerbils at a mean of 5.4 x 10(6) cfu/g of antrum and caused chronic gastritis and lesions in the antrum. In contrast, the flbA mutant did not colonise five of six gerbils and caused no lesions, indicating that motility mediated by flbA was required for colonisation. Because FlbA regulates flagellar biosynthesis and secretion, as well as forming a structural component of the flagellar secretion apparatus, two seemingly unrelated virulence attributes, motility and urease, may be coupled in H. pylori and P. mirabilis and possibly also in other motile, ureolytic bacteria.
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Affiliation(s)
| | - Christopher Coker
- Departments of Microbiology & Immunology and †Comparative Medicine, University of South Alabama College of Medicine, Mobile, AL 36688 and *Department of Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | | | - Janette M Harro
- Departments of Microbiology & Immunology and †Comparative Medicine, University of South Alabama College of Medicine, Mobile, AL 36688 and *Department of Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Susan V Gibson
- Departments of Microbiology & Immunology and †Comparative Medicine, University of South Alabama College of Medicine, Mobile, AL 36688 and *Department of Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Harry L T Mobley
- Departments of Microbiology & Immunology and †Comparative Medicine, University of South Alabama College of Medicine, Mobile, AL 36688 and *Department of Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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Tomich M, Herfst CA, Golden JW, Mohr CD. Role of flagella in host cell invasion by Burkholderia cepacia. Infect Immun 2002; 70:1799-806. [PMID: 11895941 PMCID: PMC127839 DOI: 10.1128/iai.70.4.1799-1806.2002] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Burkholderia cepacia is an important opportunistic human pathogen that affects immunocompromised individuals, particularly cystic fibrosis (CF) patients. Colonization of the lungs of a CF patient by B. cepacia can lead not only to a decline in respiratory function but also to an acute systemic infection, such as bacteremia. We have previously demonstrated that a CF clinical isolate of B. cepacia, strain J2315, can invade and survive within cultured respiratory epithelial cells. In order to further characterize the mechanisms of invasion of B. cepacia, we screened a transposon-generated mutant library of strain J2315 for mutants defective in invasion of A549 respiratory epithelial cells. Here we describe isolation and characterization of a nonmotile mutant of B. cepacia with reduced invasiveness due to disruption of fliG, which encodes a component of the motor-switch complex of the flagellar basal body. We also found that a defined null mutation in fliI, a gene encoding a highly conserved ATPase required for protein translocation via the flagellar type III secretion system, also resulted in loss of motility and a significant reduction in invasion. Both mutants lacked detectable intracellular flagellin and failed to export detectable amounts of flagellin into culture supernatants, suggesting that disruption of fliG and fliI impaired flagellar biogenesis. The reduction in invasion did not appear to be due to defective adherence of the flagellar mutants to A549 cells, suggesting that functional flagella and motility are required for full invasiveness of B. cepacia. Our findings indicate that flagellum-mediated motility may facilitate penetration of host epithelial barriers by B. cepacia, contributing to establishment of infection and systemic spread of the organism.
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Affiliation(s)
- Mladen Tomich
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota 55455-0312, USA
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Abstract
It is highly unlikely that chronic infection with H. pylori could occur in the absence of adhesin-host cell interactions. Also, there is no evidence that any of the serious outcomes of H. pylori infection such as gastric and duodenal ulcers, gastric cancer or mucosa-associated lymphoid tissue (MALT) lymphoma could occur without prior colonization of the gastric epithelium mediated by H. pylori adhesins. H. pylori is highly adaptable, as evidenced by the fact that it can occupy a single host for decades. An important facet of this adaptability is its ability to physically interact with various types of host cells and also with host mucins and extracellular matrix proteins using a number of different adhesins displaying a variety of unique receptor specificities. Thus it is highly unlikely that any one particular H. pylori adhesin will ever be proven responsible for a particular outcome such as duodenal ulcer, MALT lymphoma, or adenocarcinoma. Also, while the search for additional H. pylori adhesins should and certainly will continue, we suggest that the scope of this effort should be expanded to include investigations into the patterns of expression and interaction between individual outer membrane proteins. Which of the numerous H. pylori outer membrane proteins (OMPs) actually function as adhesins (i.e., have receptor-binding sites) and which OMPs are simply necessary for optimal display of the adhesive OMPs? There are many other important questions about H. pylori adhesins waiting to be answered. For example, which adhesins are responsible for loose adherence to host cells and which adhesins are responsible for intimate, or membrane-to-membrane, adherence, and do these adhesins normally work in concert or in a sequential fashion? Also, is a specific type of adhesin necessary for type IV protein translocation into host cells and, if so, is adhesin expression coregulated with the effector protein export?
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Affiliation(s)
- D J Evans
- Department of Medicine, VA Medical Center, and Baylor College of Medicine, Houston, Texas 77030, USA
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Abstract
Infections by Helicobacter pylori are responsible for duodenal and gastric ulcers and are a significant risk factor for the development of gastric adenocarcinoma. H. pylori was discovered in 1983, but many institutes in Canada, Europe, and the United States are already involved in programs to understand and treat the infections, as reflected by the growing number of internet sites devoted to this bacterium. Most AIDS patients and about 20% of children with acute lymphoblastic leukemia develop Pneumocystis carinii pneumoniae. Information on clinical symptoms and treatment, as well as the P. carinii genome sequencing project, are described at several web sites. Students and researchers wishing to understand the correlation between telomere length and AIDS may turn to web sites of the University of Colorado and Washington University School of Medicine for the latest on telomeres and telomerase, and their function in aging and cancer.
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