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Brackman LC, Jung MS, Ogaga EI, Joshi N, Wroblewski LE, Piazuelo MB, Peek RM, Choksi YA, Algood HMS. IL-17RA-Mediated Epithelial Cell Activity Prevents Severe Inflammatory Response to Helicobacter pylori Infection. Immunohorizons 2024; 8:339-353. [PMID: 38639570 PMCID: PMC11066722 DOI: 10.4049/immunohorizons.2300078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 03/21/2024] [Indexed: 04/20/2024] Open
Abstract
Helicobacter pylori is a Gram-negative pathogen that colonizes the stomach, induces inflammation, and drives pathological changes in the stomach tissue, including gastric cancer. As the principal cytokine produced by Th17 cells, IL-17 mediates protective immunity against pathogens by inducing the activation and mobilization of neutrophils. Whereas IL-17A is largely produced by lymphocytes, the IL-17 receptor is expressed in epithelial cells, fibroblasts, and hematopoietic cells. Loss of the IL-17RA in mice results in impaired antimicrobial responses to extracellular bacteria. In the context of H. pylori infection, this is compounded by extensive inflammation in Il17ra-/- mice. In this study, Foxa3creIl17rafl/fl (Il17raΔGI-Epi) and Il17rafl/fl (control) mice were used to test the hypothesis that IL-17RA signaling, specifically in epithelial cells, protects against severe inflammation after H. pylori infection. The data indicate that Il17raΔGI-Epi mice develop increased inflammation compared with controls. Despite reduced Pigr expression, levels of IgA increased in the gastric wash, suggesting significant increase in Ag-specific activation of the T follicular helper/B cell axis. Gene expression analysis of stomach tissues indicate that both acute and chronic responses are significantly increased in Il17raΔGI-Epi mice compared with controls. These data suggest that a deficiency of IL-17RA in epithelial cells is sufficient to drive chronic inflammation and hyperactivation of the Th17/T follicular helper/B cell axis but is not required for recruitment of polymorphonuclear neutrophils. Furthermore, the data suggest that fibroblasts can produce chemokines in response to IL-17 and may contribute to H. pylori-induced inflammation through this pathway.
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Affiliation(s)
- Lee C. Brackman
- Tennessee Valley Healthcare System, Department of Veterans Affairs, Nashville, TN
- Division of Infectious Disease, Department of Medicine, Vanderbilt University School of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Matthew S. Jung
- Tennessee Valley Healthcare System, Department of Veterans Affairs, Nashville, TN
- Division of Infectious Disease, Department of Medicine, Vanderbilt University School of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Eseoghene I. Ogaga
- Tennessee Valley Healthcare System, Department of Veterans Affairs, Nashville, TN
| | - Nikhita Joshi
- Tennessee Valley Healthcare System, Department of Veterans Affairs, Nashville, TN
- Vanderbilt University, School of Biological Sciences, Nashville, TN
| | - Lydia E. Wroblewski
- Division of Gastroenterology, Department of Medicine, Vanderbilt University School of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - M. Blanca Piazuelo
- Division of Gastroenterology, Department of Medicine, Vanderbilt University School of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Richard M. Peek
- Division of Gastroenterology, Department of Medicine, Vanderbilt University School of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Yash A. Choksi
- Tennessee Valley Healthcare System, Department of Veterans Affairs, Nashville, TN
- Division of Gastroenterology, Department of Medicine, Vanderbilt University School of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Holly M. Scott Algood
- Tennessee Valley Healthcare System, Department of Veterans Affairs, Nashville, TN
- Division of Infectious Disease, Department of Medicine, Vanderbilt University School of Medicine, Vanderbilt University Medical Center, Nashville, TN
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Vanderbilt University Medical Center, Nashville, TN
- Vanderbilt Institute of Infection, Immunity, and Inflammation, Vanderbilt University Medical Center, Nashville, TN
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Wroblewski LE, Peek RM. Clinical Pathogenesis, Molecular Mechanisms of Gastric Cancer Development. Curr Top Microbiol Immunol 2023; 444:25-52. [PMID: 38231214 PMCID: PMC10924282 DOI: 10.1007/978-3-031-47331-9_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
The human pathogen Helicobacter pylori is the strongest known risk factor for gastric disease and cancer, and gastric cancer remains a leading cause of cancer-related death across the globe. Carcinogenic mechanisms associated with H. pylori are multifactorial and are driven by bacterial virulence constituents, host immune responses, environmental factors such as iron and salt, and the microbiota. Infection with strains that harbor the cytotoxin-associated genes (cag) pathogenicity island, which encodes a type IV secretion system (T4SS) confer increased risk for developing more severe gastric diseases. Other important H. pylori virulence factors that augment disease progression include vacuolating cytotoxin A (VacA), specifically type s1m1 vacA alleles, serine protease HtrA, and the outer-membrane adhesins HopQ, BabA, SabA and OipA. Additional risk factors for gastric cancer include dietary factors such as diets that are high in salt or low in iron, H. pylori-induced perturbations of the gastric microbiome, host genetic polymorphisms, and infection with Epstein-Barr virus. This chapter discusses in detail host factors and how H. pylori virulence factors augment the risk of developing gastric cancer in human patients as well as how the Mongolian gerbil model has been used to define mechanisms of H. pylori-induced inflammation and cancer.
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Affiliation(s)
- Lydia E Wroblewski
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Richard M Peek
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
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3
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Dooyema SD, Noto JM, Wroblewski LE, Piazuelo MB, Krishna U, Suarez G, Romero-Gallo J, Delgado AG, Peek RM. Helicobacter pylori actively suppresses innate immune nucleic acid receptors. Gut Microbes 2022; 14:2105102. [PMID: 35905376 PMCID: PMC9341374 DOI: 10.1080/19490976.2022.2105102] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Chronic mucosal pathogens have evolved multiple strategies to manipulate the host immune response; consequently, microbes contribute to the development of >2 million cases of cancer/year. Gastric adenocarcinoma is the fourth leading cause of cancer-related death and Helicobacter pylori confers the highest risk for this disease. Gastric innate immune effectors can either eliminate bacteria or mobilize adaptive immune responses including Toll-like receptors (TLRs), and cytosolic DNA sensor/adaptor proteins (e.g., stimulator of interferon genes, STING). The H. pylori strain-specific cag type IV secretion system (T4SS) augments gastric cancer risk and translocates DNA into epithelial cells where it activates the microbial DNA sensor TLR9 and suppresses injury in vivo; however, the ability of H. pylori to suppress additional nucleic acid PRRs within the context of chronic gastric inflammation and injury remains undefined. In this study, in vitro and ex vivo experiments identified a novel mechanism through which H. pylori actively suppresses STING and RIG-I signaling via downregulation of IRF3 activation. In vivo, the use of genetically deficient mice revealed that Th17 inflammatory responses are heightened following H. pylori infection within the context of Sting deficiency in conjunction with increased expression of a known host immune regulator, Trim30a. This novel mechanism of immune suppression by H. pylori is likely a critical component of a finely tuned rheostat that not only regulates the initial innate immune response, but also drives chronic gastric inflammation and injury.
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Affiliation(s)
- Samuel D.R. Dooyema
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA,Microbe-Host Interactions Training Program, Vanderbilt University, Nashville, Tennessee, USA
| | - Jennifer M. Noto
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Lydia E. Wroblewski
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - M. Blanca Piazuelo
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Uma Krishna
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Giovanni Suarez
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Judith Romero-Gallo
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Alberto G. Delgado
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Richard M. Peek
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA,Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA,CONTACT Richard M. Peek Vanderbilt University Medical Center, Division of Gastroenterology, 2215 Garland Avenue, 1030C Medical Research Building IV, Nashville, TN37232, USA
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4
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Noto JM, Piazuelo MB, Shah SC, Romero-Gallo J, Hart JL, Di C, Carmichael JD, Delgado AG, Halvorson AE, Greevy RA, Wroblewski LE, Sharma A, Newton AB, Allaman MM, Wilson KT, Washington MK, Calcutt MW, Schey KL, Cummings BP, Flynn CR, Zackular JP, Peek RM. Iron deficiency linked to altered bile acid metabolism promotes Helicobacter pylori-induced inflammation-driven gastric carcinogenesis. J Clin Invest 2022; 132:e147822. [PMID: 35316215 PMCID: PMC9106351 DOI: 10.1172/jci147822] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 03/16/2022] [Indexed: 12/24/2022] Open
Abstract
Gastric carcinogenesis is mediated by complex interactions among Helicobacter pylori, host, and environmental factors. Here, we demonstrate that H. pylori augmented gastric injury in INS-GAS mice under iron-deficient conditions. Mechanistically, these phenotypes were not driven by alterations in the gastric microbiota; however, discovery-based and targeted metabolomics revealed that bile acids were significantly altered in H. pylori-infected mice with iron deficiency, with significant upregulation of deoxycholic acid (DCA), a carcinogenic bile acid. The severity of gastric injury was further augmented when H. pylori-infected mice were treated with DCA, and, in vitro, DCA increased translocation of the H. pylori oncoprotein CagA into host cells. Conversely, bile acid sequestration attenuated H. pylori-induced injury under conditions of iron deficiency. To translate these findings to human populations, we evaluated the association between bile acid sequestrant use and gastric cancer risk in a large human cohort. Among 416,885 individuals, a significant dose-dependent reduction in risk was associated with cumulative bile acid sequestrant use. Further, expression of the bile acid receptor transmembrane G protein-coupled bile acid receptor 5 (TGR5) paralleled the severity of carcinogenic lesions in humans. These data demonstrate that increased H. pylori-induced injury within the context of iron deficiency is tightly linked to altered bile acid metabolism, which may promote gastric carcinogenesis.
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Affiliation(s)
- Jennifer M Noto
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - M Blanca Piazuelo
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Shailja C Shah
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Judith Romero-Gallo
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | | | - Chao Di
- Division of Protective Immunity, and
- Department of Biomedical and Health Informatics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - James D Carmichael
- Department of Biochemistry, Mass Spectrometry Research Center Laboratory, Vanderbilt University, Nashville, Tennessee, USA
| | - Alberto G Delgado
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Alese E Halvorson
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Robert A Greevy
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Lydia E Wroblewski
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Ayushi Sharma
- Creighton University School of Medicine, Omaha, Nebraska, USA
| | | | - Margaret M Allaman
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Keith T Wilson
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, Tennessee, USA
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - M Kay Washington
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - M Wade Calcutt
- Department of Biochemistry, Mass Spectrometry Research Center Laboratory, Vanderbilt University, Nashville, Tennessee, USA
| | - Kevin L Schey
- Department of Biochemistry, Mass Spectrometry Research Center Laboratory, Vanderbilt University, Nashville, Tennessee, USA
| | - Bethany P Cummings
- Department of Surgery, University of California, Davis, Davis, California, USA
| | - Charles R Flynn
- Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Joseph P Zackular
- Division of Protective Immunity, and
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Richard M Peek
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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5
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Abstract
Helicobacter pylori is a pathogen that confers the highest known risk for gastric cancer. Research directed at understanding the pathogenesis of H. pylori is crucial to identify colonized persons that may subsequently develop neoplasia. Imai et al. describe how H. pylori elicits BRCAness and endows epithelial cells with the ability to evade apoptosis.
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Affiliation(s)
- Lydia E Wroblewski
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Richard M Peek
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
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6
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Wroblewski LE, Choi E, Petersen C, Delgado AG, Piazuelo MB, Romero-Gallo J, Lantz TL, Zavros Y, Coffey RJ, Goldenring JR, Zemper AE, Peek RM. Targeted mobilization of Lrig1 + gastric epithelial stem cell populations by a carcinogenic Helicobacter pylori type IV secretion system. Proc Natl Acad Sci U S A 2019; 116:19652-19658. [PMID: 31488717 PMCID: PMC6765285 DOI: 10.1073/pnas.1903798116] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Helicobacter pylori-induced gastritis is the strongest risk factor for gastric adenocarcinoma, a malignancy preceded by a series of well-defined histological stages, including metaplasia. One microbial constituent that augments cancer risk is the cag type 4 secretion system (T4SS), which translocates the oncoprotein CagA into host cells. Aberrant stem cell activation is linked to carcinogenesis, and Lrig1 (leucine-rich repeats and Ig-like domains 1) marks a distinct population of progenitor cells. We investigated whether microbial effectors with carcinogenic potential influence Lrig1 progenitor cells ex vivo and via lineage expansion within H. pylori-infected gastric mucosa. Lineage tracing was induced in Lrig1-CreERT2/+;R26R-YFP/+ (Lrig1/YFP) mice that were uninfected or subsequently infected with cag+H. pylori or an isogenic cagE- mutant (nonfunctional T4SS). In contrast to infection with wild-type (WT) H. pylori for 2 wk, infection for 8 wk resulted in significantly increased inflammation and proliferation in the corpus and antrum compared with uninfected or mice infected with the cagE- mutant. WT H. pylori-infected mice harbored significantly higher numbers of Lrig1/YFP epithelial cells that coexpressed UEA1 (surface cell marker). The number of cells coexpressing intrinsic factor (chief cell marker), YFP (lineage marker), and GSII lectin (spasmolytic polypeptide-expressing metaplasia marker) were increased only by WT H. pylori In human samples, Lrig1 expression was significantly increased in lesions with premalignant potential compared with normal mucosa or nonatrophic gastritis. In conclusion, chronic H. pylori infection stimulates Lrig1-expressing progenitor cells in a cag-dependent manner, and these reprogrammed cells give rise to a full spectrum of differentiated cells.
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Affiliation(s)
- Lydia E Wroblewski
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232;
| | - Eunyoung Choi
- Nashville VA Medical Center, US Department of Veterans Affairs, Nashville, TN 37212
- Section of Surgical Sciences, Vanderbilt University Medical Center, Nashville, TN 37232
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Christine Petersen
- Section of Surgical Sciences, Vanderbilt University Medical Center, Nashville, TN 37232
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Alberto G Delgado
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232
| | - M Blanca Piazuelo
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Judith Romero-Gallo
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Tyler L Lantz
- Department of Biology, University of Oregon, Eugene, OR 97403
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
| | - Yana Zavros
- Department of Pharmacology and System Physiology, University of Cincinnati, Cincinnati, OH 45221
| | - Robert J Coffey
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232
- Nashville VA Medical Center, US Department of Veterans Affairs, Nashville, TN 37212
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232
- Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN 37232
| | - James R Goldenring
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232
- Nashville VA Medical Center, US Department of Veterans Affairs, Nashville, TN 37212
- Section of Surgical Sciences, Vanderbilt University Medical Center, Nashville, TN 37232
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Anne E Zemper
- Department of Biology, University of Oregon, Eugene, OR 97403
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
| | - Richard M Peek
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232;
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232
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7
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Noto JM, Rose KL, Hachey AJ, Delgado AG, Romero-Gallo J, Wroblewski LE, Schneider BG, Shah SC, Cover TL, Wilson KT, Israel DA, Roa JC, Schey KL, Zavros Y, Piazuelo MB, Peek RM. Carcinogenic Helicobacter pylori Strains Selectively Dysregulate the In Vivo Gastric Proteome, Which May Be Associated with Stomach Cancer Progression. Mol Cell Proteomics 2019; 18:352-371. [PMID: 30455363 PMCID: PMC6356085 DOI: 10.1074/mcp.ra118.001181] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Indexed: 12/11/2022] Open
Abstract
Helicobacter pylori is the strongest risk factor for gastric cancer. Initial interactions between H. pylori and its host originate at the microbial-gastric epithelial cell interface, and contact between H. pylori and gastric epithelium activates signaling pathways that drive oncogenesis. One microbial constituent that increases gastric cancer risk is the cag pathogenicity island, which encodes a type IV secretion system that translocates the effector protein, CagA, into host cells. We previously demonstrated that infection of Mongolian gerbils with a carcinogenic cag+H. pylori strain, 7.13, recapitulates many features of H. pylori-induced gastric cancer in humans. Therefore, we sought to define gastric proteomic changes induced by H. pylori that are critical for initiation of the gastric carcinogenic cascade. Gastric cell scrapings were harvested from H. pylori-infected and uninfected gerbils for quantitative proteomic analyses using isobaric tags for relative and absolute quantitation (iTRAQ). Quantitative proteomic analysis of samples from two biological replicate experiments quantified a total of 2764 proteins, 166 of which were significantly altered in abundance by H. pylori infection. Pathway mapping identified significantly altered inflammatory and cancer-signaling pathways that included Rab/Ras signaling proteins. Consistent with the iTRAQ results, RABEP2 and G3BP2 were significantly up-regulated in vitro, ex vivo in primary human gastric monolayers, and in vivo in gerbil gastric epithelium following infection with H. pylori strain 7.13 in a cag-dependent manner. Within human stomachs, RABEP2 and G3BP2 expression in gastric epithelium increased in parallel with the severity of premalignant and malignant lesions and was significantly elevated in intestinal metaplasia and dysplasia, as well as gastric adenocarcinoma, compared with gastritis alone. These results indicate that carcinogenic strains of H. pylori induce dramatic and specific changes within the gastric proteome in vivo and that a subset of altered proteins within pathways with oncogenic potential may facilitate the progression of gastric carcinogenesis in humans.
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Affiliation(s)
- Jennifer M Noto
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Kristie L Rose
- Department of Biochemistry, Mass Spectrometry Research Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Amanda J Hachey
- Department of Biochemistry, Mass Spectrometry Research Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Alberto G Delgado
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Judith Romero-Gallo
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Lydia E Wroblewski
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Barbara G Schneider
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Shailja C Shah
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Timothy L Cover
- Division of Infectious Diseases, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee;; Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, Tennessee;; Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Keith T Wilson
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee;; Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, Tennessee;; Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Dawn A Israel
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Juan Carlos Roa
- Department of Pathology, Pontificia Universidad Catolica de Chile, Santiago, Chile
| | - Kevin L Schey
- Department of Biochemistry, Mass Spectrometry Research Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Yana Zavros
- Department of Pharmacology and System Physiology, University of Cincinnati, Cincinnati, Ohio
| | - M Blanca Piazuelo
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Richard M Peek
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee;; Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee;.
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8
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Holokai L, Chakrabarti J, Broda T, Chang J, Hawkins JA, Sundaram N, Wroblewski LE, Peek RM, Wang J, Helmrath M, Wells JM, Zavros Y. Increased Programmed Death-Ligand 1 is an Early Epithelial Cell Response to Helicobacter pylori Infection. PLoS Pathog 2019; 15:e1007468. [PMID: 30703170 PMCID: PMC6380601 DOI: 10.1371/journal.ppat.1007468] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 02/19/2019] [Accepted: 11/13/2018] [Indexed: 12/24/2022] Open
Abstract
Helicobacter pylori (H. pylori) is the major risk factor for the development of gastric cancer. Our laboratory has reported that the Sonic Hedgehog (Shh) signaling pathway is an early response to infection that is fundamental to the initiation of H. pylori-induced gastritis. H. pylori also induces programmed death ligand 1 (PD-L1) expression on gastric epithelial cells, yet the mechanism is unknown. We hypothesize that H. pylori-induced PD-L1 expression within the gastric epithelium is mediated by the Shh signaling pathway during infection. To identify the role of Shh signaling as a mediator of H. pylori-induced PD-L1 expression, human gastric organoids generated from either induced pluripotent stem cells (HGOs) or tissue (huFGOs) were microinjected with bacteria and treated with Hedgehog/Gli inhibitor GANT61. Gastric epithelial monolayers generated from the huFGOs were also infected with H. pylori and treated with GANT61 to study the role of Hedgehog signaling as a mediator of induced PD-1 expression. A patient-derived organoid/autologous immune cell co-culture system infected with H. pylori and treated with PD-1 inhibitor (PD-1Inh) was developed to study the protective mechanism of PD-L1 in response to bacterial infection. H. pylori significantly increased PD-L1 expression in organoid cultures 48 hours post-infection when compared to uninfected controls. The mechanism was cytotoxic associated gene A (CagA) dependent. This response was blocked by pretreatment with GANT61. Anti-PD-L1 treatment of H. pylori infected huFGOs, co-cultured with autologous patient cytotoxic T lymphocytes and dendritic cells, induced organoid death. H. pylori-induced PD-L1 expression is mediated by the Shh signaling pathway within the gastric epithelium. Cells infected with H. pylori that express PD-L1 may be protected from the immune response, creating premalignant lesions progressing to gastric cancer.
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Affiliation(s)
- Loryn Holokai
- Department of Molecular Genetics, Biochemistry, and Microbiology, Cincinnati OH, United States of America
| | - Jayati Chakrabarti
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati OH, United States of America
| | - Taylor Broda
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati OH, United States of America
- Center for Stem Cell and Organoid Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati OH, United States of America
| | - Julie Chang
- Department of Biomedical Engineering, University of Cincinnati, Cincinnati OH, United States of America
| | - Jennifer A. Hawkins
- Department of Pediatric Surgery, Cincinnati Children’s Hospital Medical Center, Cincinnati OH, United States of America
| | - Nambirajan Sundaram
- Department of Pediatric Surgery, Cincinnati Children’s Hospital Medical Center, Cincinnati OH, United States of America
| | - Lydia E. Wroblewski
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Richard M. Peek
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Jiang Wang
- Department of Pathology and Lab Medicine, University of Cincinnati College of Medicine, Cincinnati OH, United States of America
| | - Michael Helmrath
- Department of Pediatric Surgery, Cincinnati Children’s Hospital Medical Center, Cincinnati OH, United States of America
| | - James M. Wells
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati OH, United States of America
- Center for Stem Cell and Organoid Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati OH, United States of America
| | - Yana Zavros
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati OH, United States of America
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9
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Sierra JC, Asim M, Verriere TG, Piazuelo MB, Suarez G, Romero-Gallo J, Delgado AG, Wroblewski LE, Barry DP, Peek RM, Gobert AP, Wilson KT. Epidermal growth factor receptor inhibition downregulates Helicobacter pylori-induced epithelial inflammatory responses, DNA damage and gastric carcinogenesis. Gut 2018; 67:1247-1260. [PMID: 28473630 PMCID: PMC5671361 DOI: 10.1136/gutjnl-2016-312888] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 03/30/2017] [Accepted: 04/09/2017] [Indexed: 12/23/2022]
Abstract
OBJECTIVE Gastric cancer is the third leading cause of cancer death worldwide and infection by Helicobacter pylori is the strongest risk factor. We have reported increased epidermal growth factor receptor (EGFR) phosphorylation in the H. pylori-induced human carcinogenesis cascade, and association with DNA damage. Our goal was to determine the role of EGFR activation in gastric carcinogenesis. DESIGN We evaluated gefitinib, a specific EGFR inhibitor, in chemoprevention of H. pylori-induced gastric inflammation and cancer development. Mice with genetically targeted epithelial cell-specific deletion of Egfr (EfgrΔepi mice) were also used. RESULTS In C57BL/6 mice, gefitinib decreased Cxcl1 and Cxcl2 expression by gastric epithelial cells, myeloperoxidase-positive inflammatory cells in the mucosa and epithelial DNA damage induced by H. pylori infection. Similar reductions in chemokines, inflammatory cells and DNA damage occurred in infected EgfrΔepi versus Egfrfl/fl control mice. In H. pylori-infected transgenic insulin-gastrin (INS-GAS) mice and gerbils, gefitinib treatment markedly reduced dysplasia and carcinoma. Gefitinib blocked H. pylori-induced activation of mitogen-activated protein kinase 1/3 (MAPK1/3) and activator protein 1 in gastric epithelial cells, resulting in inhibition of chemokine synthesis. MAPK1/3 phosphorylation and JUN activation was reduced in gastric tissues from infected wild-type and INS-GAS mice treated with gefitinib and in primary epithelial cells from EfgrΔepi versus Egfrfl/fl mice. Epithelial EGFR activation persisted in humans and mice after H. pylori eradication, and gefitinib reduced gastric carcinoma in INS-GAS mice treated with antibiotics. CONCLUSIONS These findings suggest that epithelial EGFR inhibition represents a potential strategy to prevent development of gastric carcinoma in H. pylori-infected individuals.
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Affiliation(s)
- Johanna C. Sierra
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Nashville, Tennessee, USA
| | - Mohammad Asim
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Nashville, Tennessee, USA
| | - Thomas G. Verriere
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Nashville, Tennessee, USA
| | - M. Blanca Piazuelo
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Nashville, Tennessee, USA
| | - Giovanni Suarez
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Nashville, Tennessee, USA
| | - Judith Romero-Gallo
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Nashville, Tennessee, USA
| | - Alberto G. Delgado
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Nashville, Tennessee, USA
| | - Lydia E. Wroblewski
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Nashville, Tennessee, USA
| | - Daniel P. Barry
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Nashville, Tennessee, USA
| | - Richard M. Peek
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Nashville, Tennessee, USA,Department of Cancer Biology, Nashville, Tennessee, USA,Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Alain P. Gobert
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Nashville, Tennessee, USA,Center for Mucosal Inflammation and Cancer, Nashville, Tennessee, USA
| | - Keith T. Wilson
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Nashville, Tennessee, USA,Department of Cancer Biology, Nashville, Tennessee, USA,Center for Mucosal Inflammation and Cancer, Nashville, Tennessee, USA,Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA,Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, USA
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10
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Abstract
Humans are host to complex microbial communities previously termed normal flora and largely overlooked. However, resident microbes contribute to both health and disease. Investigators are beginning to define microbes that contribute to the development of gastrointestinal malignancies and the mechanisms by which this occurs. Resident microbes can induce inflammation, leading to cell proliferation and altered stem cell dynamics, which can lead to alterations in DNA integrity and immune regulation and promote carcinogenesis. Studies in human patients and rodent models of cancer have identified alterations in the microbiota of the stomach, esophagus, and colon that increase the risk for malignancy.
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Affiliation(s)
- Lydia E. Wroblewski
- Division of Gastroenterology, Department of Medicine; Vanderbilt University School of Medicine; Nashville, TN USA, T: 615-322-4215
| | - Richard M. Peek
- Division of Gastroenterology, Department of Medicine; Vanderbilt University School of Medicine; Nashville, TN USA, T: 615-343-1596
| | - Lori A. Coburn
- Veterans Affairs Tennessee Valley Healthcare System; Division of Gastroenterology, Department of Medicine; Vanderbilt University School of Medicine; Nashville, TN USA, T: 615-875-4222, F: 615-343-4229
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11
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Wroblewski LE, Piazuelo MB, Chaturvedi R, Schumacher M, Aihara E, Feng R, Noto JM, Delgado A, Israel DA, Zavros Y, Montrose MH, Shroyer N, Correa P, Wilson KT, Peek RM. Helicobacter pylori targets cancer-associated apical-junctional constituents in gastroids and gastric epithelial cells. Gut 2015; 64:720-30. [PMID: 25123931 PMCID: PMC4329117 DOI: 10.1136/gutjnl-2014-307650] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 07/30/2014] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Helicobacter pylori strains that express the oncoprotein CagA augment risk for gastric cancer. However, the precise mechanisms through which cag(+) strains heighten cancer risk have not been fully delineated and model systems that recapitulate the gastric niche are critical for understanding pathogenesis. Gastroids are three-dimensional organ-like structures that provide unique opportunities to study host-H. pylori interactions in a preclinical model. We used gastroids to inform and direct in vitro studies to define mechanisms through which H. pylori modulates expression of the cancer-associated tight junction protein claudin-7. DESIGN Gastroids were infected by luminal microinjection, and MKN28 gastric epithelial cells were cocultured with H. pylori wild-type cag(+) strains or isogenic mutants. β-catenin, claudin-7 and snail localisation was determined by immunocytochemistry. Proliferation was assessed using 5-ethynyl-2'-deoxyuridine, and levels of claudin-7 and snail were determined by western blot and flow cytometry. RESULTS Gastroids developed into a self-organising differentiation axis and H. pylori induced mislocalisation of claudin-7 and increased proliferation in a CagA- and β-catenin-dependent manner. In MKN28 cells, H pylori-induced suppression of claudin-7 was regulated by β-catenin and snail. Similarly, snail expression was increased and claudin-7 levels were decreased among H. pylori-infected individuals. CONCLUSIONS H. pylori increase proliferation in a strain-specific manner in a novel gastroid system. H. pylori also alter expression and localisation of claudin-7 in gastroids and human epithelial cells, which is mediated by β-catenin and snail activation. These data provide new insights into molecular interactions with carcinogenic potential that occur between H. pylori and epithelial cells within the gastric niche.
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Affiliation(s)
- Lydia E Wroblewski
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - M Blanca Piazuelo
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Rupesh Chaturvedi
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Michael Schumacher
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio, USA
| | - Eitaro Aihara
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio, USA
| | - Rui Feng
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio, USA
| | - Jennifer M Noto
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Alberto Delgado
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Dawn A Israel
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Yana Zavros
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio, USA
| | - Marshall H Montrose
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio, USA
| | - Noah Shroyer
- Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children’s Hospital, Cincinnati, Ohio, USA
| | - Pelayo Correa
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Keith T Wilson
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Richard M Peek
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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12
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Abstract
Helicobacter pylori infection induces chronic inflammation and is the strongest known risk factor for gastric cancer. The genomes of H pylori are highly diverse and therefore bacterial virulence factors play an important role in determining the outcome of H pylori infection, in combination with host responses that are augmented by environmental and dietary risk factors. It is important to gain further understanding of the pathogenesis of H pylori infection to develop more effective treatments for this common but deadly malignancy. This review focuses on the specific mechanisms used by H pylori to drive gastric carcinogenesis.
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Affiliation(s)
| | - Richard M. Peek
- Department of Medicine, Vanderbilt University, Nashville, TN.
,Department of Cancer Biology, Vanderbilt University, Nashville, TN
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13
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Wroblewski LE, Peek RM. When guests simply will not leave. Cell Host Microbe 2012; 12:733-4. [PMID: 23245316 DOI: 10.1016/j.chom.2012.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Chronic pathogens have evolved exquisite mechanisms of self-regulation via manipulation of host signaling pathways; however, pathologic consequences may ensue. Tsugawa et al. (2012) now report a mechanism of checks and balances used by Helicobacter pylori that is undermined by gastric stem cells, which may lower the threshold for gastric cancer.
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Affiliation(s)
- Lydia E Wroblewski
- Department of Medicine, Vanderbilt University, Nashville, TN 37232-2279, USA
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14
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Abstract
Helicobacter pylori colonizes the human gastric epithelium and induces chronic gastritis, which can lead to gastric cancer. Through cell-cell contacts the gastric epithelium forms a barrier to protect underlying tissue from pathogenic bacteria; however, H. pylori have evolved numerous strategies to perturb the integrity of the gastric barrier. In this review, we summarize recent research into the mechanisms through which H. pylori disrupts intercellular junctions and disrupts the gastric epithelial barrier.
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Affiliation(s)
- Lydia E Wroblewski
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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15
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Chaturvedi R, Asim M, Romero-Gallo J, Barry DP, Hoge S, de Sablet T, Delgado AG, Wroblewski LE, Piazuelo MB, Yan F, Israel DA, Casero RA, Correa P, Gobert AP, Polk DB, Peek RM, Wilson KT. Spermine oxidase mediates the gastric cancer risk associated with Helicobacter pylori CagA. Gastroenterology 2011; 141:1696-708.e1-2. [PMID: 21839041 PMCID: PMC3202654 DOI: 10.1053/j.gastro.2011.07.045] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 06/28/2011] [Accepted: 07/26/2011] [Indexed: 12/15/2022]
Abstract
BACKGROUND & AIMS Helicobacter pylori-induced gastric carcinogenesis has been linked to the microbial oncoprotein cytotoxin-associated gene A (CagA). Spermine oxidase (SMO) metabolizes the polyamine spermine into spermidine and generates H(2)O(2), which causes apoptosis and DNA damage. We determined if pathogenic effects of CagA are attributable to SMO. METHODS Levels of SMO, apoptosis, and DNA damage (8-oxoguanosine) were measured in gastric epithelial cell lines infected with cagA(+) or cagA(-)H pylori strains, or transfected with a CagA expression plasmid, in the absence or presence of SMO small interfering RNA, or an SMO inhibitor. The role of CagA in induction of SMO and DNA damage was assessed in H pylori-infected gastritis tissues from humans, gerbils, and both wild-type and hypergastrinemic insulin-gastrin mice, using immunohistochemistry and flow cytometry. RESULTS cagA(+) strains or ectopic expression of CagA, but not cagA(-) strains, led to increased levels of SMO, apoptosis, and DNA damage in gastric epithelial cells, and knockdown or inhibition of SMO blocked apoptosis and DNA damage. There was increased SMO expression, apoptosis, and DNA damage in gastric tissues from humans infected with cagA(+), but not cagA(-) strains. In gerbils and mice, DNA damage was CagA-dependent and present in cells that expressed SMO. Gastric epithelial cells with DNA damage that were negative for markers of apoptosis accounted for 42%-69% of cells in gerbils and insulin-gastrin mice with dysplasia and carcinoma. CONCLUSIONS By inducing SMO, H pylori CagA generates cells with oxidative DNA damage, and a subpopulation of these cells are resistant to apoptosis and thus at high risk for malignant transformation.
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Affiliation(s)
- Rupesh Chaturvedi
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN
| | - Mohammad Asim
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN
| | - Judith Romero-Gallo
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Daniel P. Barry
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN
| | - Svea Hoge
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
- Department of General, Abdominal and Vascular Surgery, Otto-von-Guericke University, Magdeburg, Germany
| | - Thibaut de Sablet
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN
| | - Alberto G. Delgado
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Lydia E. Wroblewski
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - M. Blanca Piazuelo
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Fang Yan
- Division of Gastroenterology, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN
| | - Dawn A. Israel
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Robert A. Casero
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Pelayo Correa
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Alain P. Gobert
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN
- Institut National de la Recherche Agronomique, Unité de Microbiologie UR454, Saint-Genès-Champanelle, France
| | - D. Brent Polk
- Division of Gastroenterology, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN
- Department of Pediatrics, University of Southern California Keck School of Medicine, Los Angeles, CA
| | - Richard M. Peek
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
- Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN
| | - Keith T. Wilson
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
- Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN
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16
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Nagy TA, Wroblewski LE, Wang D, Piazuelo MB, Delgado A, Romero-Gallo J, Noto J, Israel DA, Ogden SR, Correa P, Cover TL, Peek RM. β-Catenin and p120 mediate PPARδ-dependent proliferation induced by Helicobacter pylori in human and rodent epithelia. Gastroenterology 2011; 141:553-64. [PMID: 21704622 PMCID: PMC3152603 DOI: 10.1053/j.gastro.2011.05.004] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 04/28/2011] [Accepted: 05/05/2011] [Indexed: 01/28/2023]
Abstract
BACKGROUND & AIMS Colonization of gastric mucosa by Helicobacter pylori leads to epithelial hyperproliferation, which increases the risk for gastric adenocarcinoma. One H pylori virulence locus associated with cancer risk, cag, encodes a secretion system that transports effectors into host cells and leads to aberrant activation of β-catenin and p120-catenin (p120). Peroxisome proliferator-activated receptor (PPAR)δ is a ligand-activated transcription factor that affects oncogenesis in conjunction with β-catenin. We used a carcinogenic H pylori strain to define the role of microbial virulence constituents and PPARδ in regulating epithelial responses that mediate development of adenocarcinoma. METHODS Gastric epithelial cells or colonies were co-cultured with the H pylori cag(+) strain 7.13 or cagE(-), cagA(-), soluble lytic transglycosylase(-), or cagA(-)/soluble lytic transglycosylase(-) mutants. Levels of PPARδ and cyclin E1 were determined by real-time, reverse-transcription polymerase chain reaction, immunoblot analysis, or immunofluorescence microscopy; proliferation was measured in 3-dimensional culture. PPARδ and Ki67 expression were determined by immunohistochemical analysis of human biopsies and rodent gastric mucosa. RESULTS H pylori induced β-catenin- and p120-dependent expression and activation of PPARδ in gastric epithelial cells, which were mediated by the cag secretion system substrates CagA and peptidoglycan. H pylori stimulated proliferation in vitro, which required PPARδ-mediated activation of cyclin E1; H pylori did not induce expression of cyclin E1 in a genetic model of PPARδ deficiency. PPARδ expression and proliferation in rodent and human gastric tissue was selectively induced by cag(+) strains and PPARδ levels normalized after eradication of H pylori. CONCLUSIONS The H pylori cag secretion system activates β-catenin, p120, and PPARδ, which promote gastric epithelial cell proliferation via activation of cyclin E1. PPARδ might contribute to gastric adenocarcinoma development in humans.
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Affiliation(s)
- Toni A. Nagy
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University, Nashville, TN, USA 37232
| | - Lydia E. Wroblewski
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University, Nashville, TN, USA 37232
| | - Dingzhi Wang
- Department of Cancer Biology, MD Anderson Cancer Center, University of Texas, Houston, TX, USA 77030
| | - M. Blanca Piazuelo
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University, Nashville, TN, USA 37232
| | - Alberto Delgado
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University, Nashville, TN, USA 37232
| | - Judith Romero-Gallo
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University, Nashville, TN, USA 37232
| | - Jennifer Noto
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University, Nashville, TN, USA 37232
| | - Dawn A. Israel
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University, Nashville, TN, USA 37232
| | - Seth R. Ogden
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University, Nashville, TN, USA 37232
| | - Pelayo Correa
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University, Nashville, TN, USA 37232
| | - Timothy L. Cover
- Division of Infectious Diseases, Department of Medicine, Vanderbilt University, Nashville, TN 37232, Department of Veterans Affairs Medical Center, Nashville, Tennessee, USA 37212
| | - Richard M. Peek
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University, Nashville, TN, USA 37232, Department of Veterans Affairs Medical Center, Nashville, Tennessee, USA 37212
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17
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Nagy TA, Allen SS, Wroblewski LE, Flaherty DK, Slaughter JC, Perez-Perez G, Israel DA, Peek RM. Helicobacter pylori induction of eosinophil migration is mediated by the cag pathogenicity island via microbial-epithelial interactions. Am J Pathol 2011; 178:1448-52. [PMID: 21406172 DOI: 10.1016/j.ajpath.2010.12.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Revised: 11/16/2010] [Accepted: 12/17/2010] [Indexed: 01/23/2023]
Abstract
The host immune response directed against Helicobacter pylori is ineffective in eliminating the organism and strains harboring the cag pathogenicity island augment disease risk. Because eosinophils are a prominent component of H. pylori-induced gastritis, we investigated microbial and host mechanisms through which H. pylori regulates eosinophil migration. Our results indicate that H. pylori increases production of the chemokines CCL2, CCL5, and granulocyte-macrophage colony-stimulating factor by gastric epithelial cells and that these molecules induce eosinophil migration. These events are mediated by the cag pathogenicity island and by mitogen-activated protein kinases, suggesting that eosinophil migration orchestrated by H. pylori is regulated by a virulence-related locus.
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Affiliation(s)
- Toni A Nagy
- Division of Gastroenterology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-2279, USA
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18
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Wroblewski LE, Shen L, Ogden S, Romero-Gallo J, Lapierre LA, Israel DA, Turner JR, Peek RM. Helicobacter pylori dysregulation of gastric epithelial tight junctions by urease-mediated myosin II activation. Gastroenterology 2009; 136:236-46. [PMID: 18996125 PMCID: PMC2678540 DOI: 10.1053/j.gastro.2008.10.011] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Revised: 09/26/2008] [Accepted: 10/02/2008] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Helicobacter pylori-induced gastritis predisposes to the development of gastric cancer. Increased epithelial tight junction permeability and alterations in apical-junctional complexes are also associated with an increased risk of carcinogenesis. Phosphorylation of myosin regulatory light chain (MLC) by MLC kinase (MLCK) regulates tight junction function. We determined whether MLCK was activated by H pylori and defined the mechanisms through which such activation dysregulates gastric epithelial barrier function. METHODS MKN28 gastric epithelial cells were cocultured with the H pylori cag(+) strain 60190 or cagA(-), cagE(-), ureB(-), or vacA(-) mutants. MLC phosphorylation and barrier integrity were determined by immunoblot analysis and transepithelial electrical resistance measurements, respectively. Localization of the tight junction protein occludin was determined by immunocytochemistry in MKN28 cells and INS-GAS mice. RESULTS H pylori induced a progressive loss of barrier function that was attenuated by inactivation of ureB, but not cagA, cagE, or vacA. Reductions in transepithelial electrical resistance were also dependent on functional urease activity. H pylori increased MLC phosphorylation in epithelial monolayers; this was significantly decreased by inhibition of MLCK or Rho kinase or by loss of UreB. H pylori infection of either cultured monolayers or hypergastrinemic INS-GAS mice induced occludin endocytosis, reflecting cytoskeletally mediated disruption of tight junctions. CONCLUSIONS H pylori increases MLC phosphorylation, occludin internalization and barrier dysfunction in gastric epithelial cells. This process requires functional urease activity and is independent of the cag pathogenicity island or VacA. These data provide new insights into the mechanisms by which H pylori disrupts gastric barrier function.
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Affiliation(s)
- Lydia E. Wroblewski
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN, 37232-2279, USA
| | - Le Shen
- Department of Pathology, The University of Chicago, Chicago, IL 60637, USA
| | - Seth Ogden
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN, 37232-2279, USA
| | - Judith Romero-Gallo
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN, 37232-2279, USA
| | - Lynne A. Lapierre
- Department of Surgery, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Dawn A. Israel
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN, 37232-2279, USA
| | - Jerrold R. Turner
- Department of Pathology, The University of Chicago, Chicago, IL 60637, USA
| | - Richard M. Peek
- Division of Gastroenterology, Departments of Medicine and Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN, 37232-2279, USA
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19
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Ogden SR, Wroblewski LE, Weydig C, Romero-Gallo J, O'Brien DP, Israel DA, Krishna US, Fingleton B, Reynolds AB, Wessler S, Peek RM. p120 and Kaiso regulate Helicobacter pylori-induced expression of matrix metalloproteinase-7. Mol Biol Cell 2008; 19:4110-21. [PMID: 18653469 DOI: 10.1091/mbc.e08-03-0283] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Helicobacter pylori is the strongest known risk factor for gastric adenocarcinoma, yet only a fraction of infected persons develop cancer. One H. pylori constituent that augments disease risk is the cytotoxin-associated gene (cag) pathogenicity island, which encodes a secretion system that translocates bacterial effector molecules into host cells. Matrix metalloproteinase (MMP)-7, a member of a family of enzymes with tumor-initiating properties, is overexpressed in premalignant and malignant gastric lesions, and H. pylori cag(+) strains selectively increase MMP-7 protein levels in gastric epithelial cells in vitro and in vivo. We now report that H. pylori-mediated mmp-7 induction is transcriptionally regulated via aberrant activation of p120-catenin (p120), a component of adherens junctions. H. pylori increases mmp-7 mRNA levels in a cag- and p120-dependent manner and induces translocation of p120 to the nucleus in vitro and in a novel ex vivo gastric gland culture system. Nuclear translocation of p120 in response to H. pylori relieves Kaiso-mediated transcriptional repression of mmp-7, which is implicated in tumorigenesis. These results indicate that selective and coordinated induction of mmp-7 expression by H. pylori cag(+) isolates may explain in part the augmentation in gastric cancer risk associated with these strains.
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Affiliation(s)
- Seth R Ogden
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-2279, USA
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Franco AT, Johnston E, Krishna U, Yamaoka Y, Israel DA, Nagy TA, Wroblewski LE, Piazuelo MB, Correa P, Peek RM. Regulation of gastric carcinogenesis by Helicobacter pylori virulence factors. Cancer Res 2008; 68:379-87. [PMID: 18199531 DOI: 10.1158/0008-5472.can-07-0824] [Citation(s) in RCA: 224] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Helicobacter pylori is the strongest known risk factor for gastric adenocarcinoma, and strains that possess the cag secretion system, which translocates the bacterial effector CagA into host cells, augment cancer risk. H. pylori strains that express the vacuolating cytotoxin or the outer membrane protein OipA are similarly associated with severe pathologic outcomes. We previously reported that an in vivo adapted H. pylori strain, 7.13, induces gastric adenocarcinoma in rodent models of gastritis. In the current study, we used carcinogenic strain 7.13 as a prototype to define the role of virulence constituents in H. pylori-mediated carcinogenesis. Mongolian gerbils were infected with wild-type strain 7.13 or cagA(-), vacA(-), or oipA(-) mutants for 12 to 52 weeks. All infected gerbils developed gastritis; however, inflammation was significantly attenuated in animals infected with the cagA(-) but not the vacA(-) or oipA(-) strains. Gastric dysplasia and cancer developed in >50% of gerbils infected with either the wild-type or vacA(-) strain but in none of the animals infected with the cagA(-) strain. Inactivation of oipA decreased beta-catenin nuclear localization in vitro and reduced the incidence of cancer in gerbils. OipA expression was detected significantly more frequently among H. pylori strains isolated from human subjects with gastric cancer precursor lesions versus persons with gastritis alone. These results indicate that loss of CagA prevents the development of cancer in this model. Inactivation of oipA attenuates beta-catenin nuclear translocation and also decreases the incidence of carcinoma. In addition to defining factors that mediate H. pylori-induced cancer, these results provide insight into mechanisms that may regulate the development of other malignancies arising within the context of inflammatory states.
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Affiliation(s)
- Aime T Franco
- Division of Gastroenterology, Department of Medicine, Vanderbilt University, Nashville, TN 37232-2279, USA
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Abstract
Chronic Helicobacter pylori infection is the strongest known risk factor for the development of gastric cancer. In order to survive and propagate under the harsh conditions of the gastric niche, this pathogen has evolved numerous means to interact with host epithelium. In this issue, Mimuro et al. shed light on mechanisms by which Helicobacter pylori attenuates apoptosis in the gastric epithelium to facilitate its persistence within the human stomach.
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Affiliation(s)
- Lydia E Wroblewski
- Department of Medicine, Division of Gastroenterology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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Wroblewski LE, Noble PJM, Pagliocca A, Pritchard DM, Hart CA, Campbell F, Dodson AR, Dockray GJ, Varro A. Stimulation of MMP-7 (matrilysin) by Helicobacter pylori in human gastric epithelial cells: role in epithelial cell migration. J Cell Sci 2003; 116:3017-26. [PMID: 12808021 DOI: 10.1242/jcs.00518] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Epithelial cell responses to bacterial infection include induction of matrix metalloproteinase 7 (MMP-7). Here, we identify increased MMP-7 expression in the gastric epithelium in response to the oncogenic bacterium Helicobacter pylori, and report on the mechanisms and consequences for gastric epithelial cell migration. In patients infected with H. pylori, there was increased MMP-7 in gastric biopsies detected by western blot. MMP-7 was localized to the advancing edge of migrating gastric epithelial cell colonies, including lamellipodia. Rates of spreading of gastric gland cells were higher in H. pylori-infected cultures compared with control, and this was inhibited by antisense oligonucleotides to MMP-7. Complementary data were obtained in a gastric cancer cell line (AGS cells). In the latter, H. pylori induced expression of an MMP-7-luciferase promoter/reporter vector through mechanisms that involved activation of Rho and Rac. RhoA acted through activation of both NF-kappaB and AP-1, whereas Rac activated NF-kappaB but not AP-1. MMP-7 is commonly upregulated in gastric cancer; since H. pylori is a recognized gastric carcinogen, the data suggest a new mechanism by which the bacterium might predispose towards gastric neoplasia.
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Affiliation(s)
- Lydia E Wroblewski
- Physiological Laboratory, University of Liverpool, Liverpool L69 3BX, UK
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Pagliocca A, Wroblewski LE, Ashcroft FJ, Noble PJ, Dockray GJ, Varro A. Stimulation of the gastrin-cholecystokinin(B) receptor promotes branching morphogenesis in gastric AGS cells. Am J Physiol Gastrointest Liver Physiol 2002; 283:G292-9. [PMID: 12121875 DOI: 10.1152/ajpgi.00056.2002] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Epithelial organization is maintained by cell proliferation, migration, and differentiation. In the case of the gastric epithelium, at least some of these events are regulated by the hormone gastrin. In addition, gastric epithelial cells are organized into characteristic tubular structures (the gastric glands), but the cellular mechanisms regulating the organization of tubular structures (sometimes called branching morphogenesis) are uncertain. In the present study, we examined the role of the gastrin-cholecystokinin(B) receptor in promoting branching morphogenesis of gastric epithelial cells. When gastric cancer AGS-G(R) cells were cultured on plastic, gastrin and PMA stimulated cell adhesion, formation of lamellipodia, and extension of long processes in part by activation of protein kinase C (PKC) and phosphatidylinositol (PI)-3 kinase. Branching morphogenesis was not observed in these circumstances. However, when cells were cultured on artificial basement membrane, the same stimuli increased the formation of organized multicellular arrays, exhibiting branching morphogenesis. These effects were reversed by inhibitors of PKC but not of PI-3 kinase. We conclude that, in the presence of basement membrane, activation of PKC by gastrin stimulates branching morphogenesis.
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Affiliation(s)
- A Pagliocca
- Physiological Laboratory, University of Liverpool, United Kingdom
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Wroblewski LE, Pritchard DM, Carter S, Varro A. Gastrin-stimulated gastric epithelial cell invasion: the role and mechanism of increased matrix metalloproteinase 9 expression. Biochem J 2002; 365:873-9. [PMID: 11971760 PMCID: PMC1222716 DOI: 10.1042/bj20020068] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2002] [Revised: 03/22/2002] [Accepted: 04/24/2002] [Indexed: 12/26/2022]
Abstract
The gastric hormone gastrin regulates the organization of the gastric epithelium, but the cellular control mechanisms are yet unknown. Epithelial remodelling typically involves extracellular proteolysis mediated by the matrix metalloproteinases (MMPs). Since a gene-array analysis of the gastric cancer cell line AGS-G(R) suggested that gastrin increased MMP-9 expression, we examined the control of MMP-9 expression by gastrin. Gelatin zymography confirmed gastrin induction of MMP-9 in AGS-G(R) cells, but showed a small inhibition of MMP-2. Immunocytochemical studies showed that MMP-9 was localized to vesicles that appeared to traffic along the processes that were extended in response to gastrin. Gastrin stimulated the invasion of AGS-G(R) cells through artificial basement membrane, which was reduced by an inhibitor of MMP-2/-9. There was also an increase in MMP-9 in the stomach of patients with elevated plasma gastrin and multiple-endocrine neoplasia type 1 (MEN-1) syndrome, suggesting in vivo regulation of MMP-9 expression by gastrin. Finally, we showed that the expression of 1.9 kb of human MMP-9 gene promoter coupled with luciferase (MMP-9-luc) was increased 7.65+/-1.2-fold by gastrin, via a pathway which includes stimulation of protein kinase C, and activation of Raf and the mitogen-activated protein (MAP) kinase pathway. The tumour suppressor menin (which is mutated in MEN-1 syndrome) inhibited the expression of MMP-9-luc by gastrin. These results suggest that gastrin increases MMP-9 expression, which is associated with increased invasion, and this is a putative mechanism regulating remodelling of the gastric epithelium.
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Affiliation(s)
- Lydia E Wroblewski
- Physiological Laboratory, University of Liverpool, Crown Street, Liverpool L69 3BX, U.K
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Varro A, Noble PJ, Wroblewski LE, Bishop L, Dockray GJ. Gastrin-cholecystokinin(B) receptor expression in AGS cells is associated with direct inhibition and indirect stimulation of cell proliferation via paracrine activation of the epidermal growth factor receptor. Gut 2002; 50:827-33. [PMID: 12010885 PMCID: PMC1773243 DOI: 10.1136/gut.50.6.827] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
BACKGROUND Activation of the gastrin-cholecystokinin(B) (CCK(B)) receptor stimulates cell proliferation and increases production of ligands for the epidermal growth factor receptor (EGF-R). AIMS To determine the role of gastrin-CCK(B) activation in stimulation of cell proliferation via paracrine activation of EGF-R. METHODS AGS cells were transfected with the gastrin-CCK(B) receptor (AGS-G(R) cells) or with green fluorescent protein (AGS-GFP cells). Proliferation was determined by [(3)H] thymidine incorporation, flow cytometry, and cell counting. RESULTS Gastrin inhibited proliferation of AGS-G(R) cells by delaying entry into S phase. However, when AGS-G(R) cells were cocultured with AGS-GFP cells, gastrin stimulated proliferation of the latter. Immunoneutralisation and pharmacological studies using metalloproteinase and kinase inhibitors indicated that the proliferative response was mediated by paracrine stimulation of EGF-R and activation of the mitogen activated protein kinase pathway through release of heparin binding EGF. CONCLUSIONS Gastrin can directly inhibit, and indirectly stimulate, proliferation of gastric AGS cells.
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Affiliation(s)
- A Varro
- Physiological Laboratory, University of Liverpool, Liverpool, UK.
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