scholarly journals Regulation of RANTES Promoter Activation in Gastric Epithelial Cells Infected with Helicobacter pylori

2005 ◽  
Vol 73 (11) ◽  
pp. 7602-7612 ◽  
Author(s):  
Takahiko Kudo ◽  
Hong Lu ◽  
Jeng Yih Wu ◽  
David Y. Graham ◽  
Antonella Casola ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Inflammatory Response ◽  
Luciferase Reporter ◽  
Antral Mucosa ◽  
Mrna Levels ◽  
Gastric Epithelial Cells ◽  
Rantes Promoter ◽  
H Pylori ◽  
Responsive Element

ABSTRACT RANTES, a CC chemokine, plays an important role in the inflammatory response associated with Helicobacter pylori infection. However, the mechanism by which H. pylori induces RANTES expression in the gastric mucosa is unknown. We cocultured gastric epithelial cells with wild-type H. pylori, isogenic oipA mutants, cag pathogenicity island (PAI) mutants, or double knockout mutants. Reverse transcriptase PCR showed that RANTES mRNA was induced by H. pylori and that the expression was both OipA and cag PAI dependent. Luciferase reporter gene assays and electrophoretic mobility shift assays showed that maximal H. pylori-induced RANTES gene transcription required the presence of the interferon-stimulated responsive element (ISRE), the cyclic AMP-responsive element (CRE), nuclear factor-interleukin 6 (NF-IL-6), and two NF-κB sites. OipA- and cag PAI-dependent pathways included NF-κB→NF-κB/NF-IL-6/ISRE pathways, and cag PAI-dependent pathways additionally included Jun N-terminal kinase→CRE/NF-κB pathways. The OipA-dependent pathways additionally included p38→CRE/ISRE pathways. We confirmed the in vitro effects in vivo by examining RANTES mRNA levels in biopsy specimens from human gastric antral mucosa. RANTES mRNA levels in the antral mucosa were significantly higher for patients infected with cag PAI/OipA-positive H. pylori than for those infected with cag PAI/OipA-negative H. pylori or uninfected patients. The mucosal inflammatory response to H. pylori infection involves different signaling pathways for activation of the RANTES promoter, with both OipA and the cag PAI being required for full activation of the RANTES promoter.

scholarly journals Helicobacter pylori Induces RANTES through Activation of NF-κB

2003 ◽  
Vol 71 (7) ◽  
pp. 3748-3756 ◽  
Author(s):  
Naoki Mori ◽  
Alan M. Krensky ◽  
Romas Geleziunas ◽  
Akihiro Wada ◽  
Toshiya Hirayama ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Gastric Mucosa ◽  
Epithelial Cells ◽  
Intracellular Signaling ◽  
Interleukin 1 ◽  
Luciferase Reporter ◽  
Transcriptional Level ◽  
Gastric Epithelial Cells ◽  
Rantes Promoter ◽  
H Pylori

ABSTRACT Helicobacter pylori-infected gastric mucosa displays a conspicuous infiltration of mononuclear cells and neutrophils. RANTES (short for “regulated upon activation, normal T cell expressed and secreted”) is a chemoattractant cytokine (chemokine) important in the infiltration of T lymphocytes and monocytes. RANTES may therefore contribute to the cellular infiltrate in the H. pylori-infected gastric mucosa. The aim of this study was to analyze the molecular mechanism responsible for H. pylori-mediated RANTES expression. We observed that gastric epithelial cells produced RANTES upon coculture with H. pylori. In addition, H. pylori induced RANTES mRNA expression and an increase in luciferase activity in cells which were transfected with a luciferase reporter construct derived from the RANTES promoter, in gastric epithelial cells, indicating that the induction of RANTES production occurred at the transcriptional level. Induction of RANTES was dependent on an intact cag pathogenicity island. Activation of the RANTES promoter by H. pylori occurred through the action of NF-κB. Transfection of kinase-deficient mutants of IκB kinase (IKK) and NF-κB-inducing kinase (NIK) inhibited H. pylori-mediated RANTES activation. In contrast, tumor necrosis factor alpha- or interleukin-1/Toll-like receptor signaling molecules—such as mitogen-activated protein kinase/extracellular signal-regulated kinase kinase 1, MyD88, and interleukin-1 receptor-associated kinase—did not play a role in RANTES activation by H. pylori. Collectively, H. pylori induced NF-κB activation through an intracellular signaling pathway that involved IKK and NIK, leading to RANTES gene transcription. RANTES induction by H. pylori may play an important role in gastric inflammation.

scholarly journals TIFA Signaling in Gastric Epithelial Cells Initiates the cag Type 4 Secretion System-Dependent Innate Immune Response to Helicobacter pylori Infection

mBio ◽  
2017 ◽  
Vol 8 (4) ◽  
Author(s):  
Alevtina Gall ◽  
Ryan G. Gaudet ◽  
Scott D. Gray-Owen ◽  
Nina R. Salama
Keyword(s):  
Immune Response ◽  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Inflammatory Response ◽  
Secretion System ◽  
Innate Immune ◽  
Gastric Ulcers ◽  
Bacterial Clearance ◽  
Gastric Epithelial Cells ◽  
H Pylori

ABSTRACT Helicobacter pylori is a bacterial pathogen that colonizes the human stomach, causing inflammation which, in some cases, leads to gastric ulcers and cancer. The clinical outcome of infection depends on a complex interplay of bacterial, host genetic, and environmental factors. Although H. pylori is recognized by both the innate and adaptive immune systems, this rarely results in bacterial clearance. Gastric epithelial cells are the first line of defense against H. pylori and alert the immune system to bacterial presence. Cytosolic delivery of proinflammatory bacterial factors through the cag type 4 secretion system ( cag -T4SS) has long been appreciated as the major mechanism by which gastric epithelial cells detect H. pylori . Classically attributed to the peptidoglycan sensor NOD1, recent work has highlighted the role of NOD1-independent pathways in detecting H. pylori ; however, the bacterial and host factors involved have remained unknown. Here, we show that bacterially derived heptose-1,7-bisphosphate (HBP), a metabolic precursor in lipopolysaccharide (LPS) biosynthesis, is delivered to the host cytosol through the cag -T4SS, where it activates the host tumor necrosis factor receptor-associated factor (TRAF)-interacting protein with forkhead-associated domain (TIFA)-dependent cytosolic surveillance pathway. This response, which is independent of NOD1, drives robust NF-κB-dependent inflammation within hours of infection and precedes NOD1 activation. We also found that the CagA toxin contributes to the NF-κB-driven response subsequent to TIFA and NOD1 activation. Taken together, our results indicate that the sequential activation of TIFA, NOD1, and CagA delivery drives the initial inflammatory response in gastric epithelial cells, orchestrating the subsequent recruitment of immune cells and leading to chronic gastritis. IMPORTANCE H. pylori is a globally prevalent cause of gastric and duodenal ulcers and cancer. H. pylori antibiotic resistance is rapidly increasing, and a vaccine remains elusive. The earliest immune response to H. pylori is initiated by gastric epithelial cells and sets the stage for the subsequent immunopathogenesis. This study revealed that host TIFA and H. pylori -derived HBP are critical effectors of innate immune signaling that account for much of the inflammatory response to H. pylori in gastric epithelial cells. HBP is delivered to the host cell via the cag -T4SS at a time point that precedes activation of the previously described NOD1 and CagA inflammatory pathways. Manipulation of the TIFA-driven immune response in the host and/or targeting of ADP-heptose biosynthesis enzymes in H. pylori may therefore provide novel strategies that may be therapeutically harnessed to achieve bacterial clearance.

scholarly journals Activation of Intercellular Adhesion Molecule 1 Expression by Helicobacter pylori Is Regulated by NF-κB in Gastric Epithelial Cancer Cells

2000 ◽  
Vol 68 (4) ◽  
pp. 1806-1814 ◽  
Author(s):  
Naoki Mori ◽  
Akihiro Wada ◽  
Toshiya Hirayama ◽  
Thomas P. Parks ◽  
Christian Stratowa ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Adhesion Molecule ◽  
Intercellular Adhesion ◽  
Intercellular Adhesion Molecule ◽  
Luciferase Reporter ◽  
Pyrrolidine Dithiocarbamate ◽  
Mrna Levels ◽  
Intercellular Adhesion Molecule 1 ◽  
H Pylori

ABSTRACT Interactions between leukocytes and epithelial cells may play a key role in Helicobacter pylori-associated gastric mucosal inflammation. This process is mediated by various cell adhesion molecules. The present study examined the molecular mechanisms leading to H. pylori-induced epithelial cell intercellular adhesion molecule-1 (ICAM-1; also called CD54) expression. Coculture of epithelial cells with cytotoxin-associated gene pathogenicity island-positive (cag PAI+) H. pylori strains, but not with a cag PAI−strain or H. pylori culture supernatants, resulted in upregulation of steady-state mRNA levels and cell surface expression of ICAM-1. Coculture with H. pylori induced an increase in luciferase activity in cells which were transfected with a luciferase reporter gene linked to the 5′-flanking region of the ICAM-1 gene.H. pylori activated the ICAM-1 promoter via the NF-κB binding site. An inducible nuclear protein complex bound to the ICAM-1 NF-κB site and was identified as the NF-κB p50–p65 heterodimer.H. pylori induced the degradation of IκB-α, a major cytoplasmic inhibitor of NF-κB, and stimulated the expression of IκB-α mRNA. Pretreatment of epithelial cells with pyrrolidine dithiocarbamate, which blocks NF-κB activation, inhibited H. pylori-induced ICAM-1 expression. THP-1 macrophagic cells, peripheral blood mononuclear cells, and purified neutrophils adhered toH. pylori-infected epithelial cells to a greater extent than to uninfected cells. These results show that H. pyloridirectly induces expression of ICAM-1 on gastric epithelial cells in an NF-κB-dependent manner that may support leukocyte attachment during inflammation.

scholarly journals Chemokines and Antimicrobial Peptides Have acag-Dependent Early Response to Helicobacter pylori Infection in Primary Human Gastric Epithelial Cells

2014 ◽  
Vol 82 (7) ◽  
pp. 2881-2889 ◽  
Author(s):  
Pascale Mustapha ◽  
Isabelle Paris ◽  
Magali Garcia ◽  
Cong Tri Tran ◽  
Julie Cremniter ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Inflammatory Response ◽  
Antimicrobial Peptides ◽  
Virulence Factors ◽  
Inflammatory Mediator ◽  
Host Cells ◽  
Gastric Epithelial Cells ◽  
Content Type ◽  
H Pylori

ABSTRACTHelicobacter pyloriinfection systematically causes chronic gastric inflammation that can persist asymptomatically or evolve toward more severe gastroduodenal pathologies, such as ulcer, mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric cancer. Thecagpathogenicity island (cagPAI) ofH. pyloriallows translocation of the virulence protein CagA and fragments of peptidoglycan into host cells, thereby inducing production of chemokines, cytokines, and antimicrobial peptides. In order to characterize the inflammatory response toH. pylori, a new experimental protocol for isolating and culturing primary human gastric epithelial cells was established using pieces of stomach from patients who had undergone sleeve gastrectomy. Isolated cells expressed markers indicating that they were mucin-secreting epithelial cells. Challenge of primary epithelial cells withH. pyloriB128 underscored early dose-dependent induction of expression of mRNAs of the inflammatory mediators CXCL1 to -3, CXCL5, CXCL8, CCL20, BD2, and tumor necrosis factor alpha (TNF-α). In AGS cells, significant expression of only CXCL5 and CXCL8 was observed following infection, suggesting that these cells were less reactive than primary epithelial cells. Infection of both cellular models withH. pyloriB128ΔcagM, acagPAI mutant, resulted in weak inflammatory-mediator mRNA induction. At 24 h after infection of primary epithelial cells withH. pylori, inflammatory-mediator production was largely due tocagPAI substrate-independent virulence factors. Thus,H. pyloricagPAI substrate appears to be involved in eliciting an epithelial response during the early phases of infection. Afterwards, other virulence factors of the bacterium take over in development of the inflammatory response. Using a relevant cellular model, this study provides new information on the modulation of inflammation duringH. pyloriinfection.

scholarly journals Helicobacter pylori infection downregulates the DNA glycosylase NEIL2, resulting in increased genome damage and inflammation in gastric epithelial cells

2020 ◽  
Vol 295 (32) ◽  
pp. 11082-11098 ◽  
Author(s):  
Ibrahim M. Sayed ◽  
Ayse Z. Sahan ◽  
Tatiana Venkova ◽  
Anirban Chakraborty ◽  
Dibyabrata Mukhopadhyay ◽  
...  
Keyword(s):  
Dna Damage ◽  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Inflammatory Response ◽  
Oxidative Dna Damage ◽  
Expression Profiles ◽  
Dna Glycosylase ◽  
Gastric Epithelial Cells ◽  
Genome Damage ◽  
H Pylori

Infection with the Gram-negative, microaerophilic bacterium Helicobacter pylori induces an inflammatory response and oxidative DNA damage in gastric epithelial cells that can lead to gastric cancer (GC). However, the underlying pathogenic mechanism is largely unclear. Here, we report that the suppression of Nei-like DNA glycosylase 2 (NEIL2), a mammalian DNA glycosylase that specifically removes oxidized bases, is one mechanism through which H. pylori infection may fuel the accumulation of DNA damage leading to GC. Using cultured cell lines, gastric biopsy specimens, primary cells, and human enteroid-derived monolayers from healthy human stomach, we show that H. pylori infection greatly reduces NEIL2 expression. The H. pylori infection-induced downregulation of NEIL2 was specific, as Campylobacter jejuni had no such effect. Using gastric organoids isolated from the murine stomach in coculture experiments with live bacteria mimicking the infected stomach lining, we found that H. pylori infection is associated with the production of various inflammatory cytokines. This response was more pronounced in Neil2 knockout (KO) mouse cells than in WT cells, suggesting that NEIL2 suppresses inflammation under physiological conditions. Notably, the H. pylori-infected Neil2-KO murine stomach exhibited more DNA damage than the WT. Furthermore, H. pylori-infected Neil2-KO mice had greater inflammation and more epithelial cell damage. Computational analysis of gene expression profiles of DNA glycosylases in gastric specimens linked the reduced Neil2 level to GC progression. Our results suggest that NEIL2 downregulation is a plausible mechanism by which H. pylori infection impairs DNA damage repair, amplifies the inflammatory response, and initiates GC.

scholarly journals Effects ofHelicobacter pyloriand Heat Shock Protein 70 on the Proliferation of Human Gastric Epithelial Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Liping Tao ◽  
Hai Zou ◽  
Zhimin Huang
Keyword(s):  
Helicobacter Pylori ◽  
Heat Shock ◽  
Epithelial Cells ◽  
Heat Shock Protein ◽  
Mtt Assay ◽  
Heat Shock Protein 70 ◽  
Hsp70 Expression ◽  
Gastric Epithelial Cells ◽  
Ags Cells ◽  
H Pylori

Infection ofHelicobacter pylori (H. pylori)changed the proliferation of gastric epithelial cells and decreased the expression of heat shock protein 70 (HSP70). However, the effects ofH. pylorion the proliferation of gastric epithelial cells and the roles of HSP70 during the progress need further investigation.Objective.To investigate the effects ofHelicobacter pylori (H. pylori)and heat shock protein 70 (HSP70) on the proliferation of human gastric epithelial cells.Methods. H. pyloriand a human gastric epithelial cell line (AGS) were cocultured. The proliferation of AGS cells was quantitated by an MTT assay, and the expression of HSP70 in AGS cells was detected by Western blotting. HSP70 expression in AGS cells was silenced by small interfering RNA (siRNA) to investigate the role of HSP70. ThesiRNA-treated AGS cells were cocultured withH. pyloriand cell proliferation was measured by an MTT assay.Results.The proliferation of AGS cells was accelerated by coculturing withH. pylorifor 4 and 8 h, but was suppressed at 24 and 48 h. HSP70 expression was decreased in AGS cells infected byH. pylorifor 48 h. The proliferation in HSP70-silenced AGS cells was inhibited after coculturing withH. pylorifor 24 and 48 h compared with the control group.Conclusions.Coculture ofH. pylorialtered the proliferation of gastric epithelial cells and decreased HSP70 expression. HSP70 knockdown supplemented the inhibitory effect ofH. pylorion proliferation of epithelial cells. These results indicate that the effects ofH. pylorion the proliferation of gastric epithelial cells at least partially depend on the decreased expression of HSP70 induced by the bacterium.

scholarly journals Suppression of IL-8 production in gastric epithelial cells by MUC1 mucin and peroxisome proliferator-associated receptor-γ

2012 ◽  
Vol 303 (6) ◽  
pp. G765-G774 ◽  
Author(s):  
Yong Sung Park ◽  
Wei Guang ◽  
Thomas G. Blanchard ◽  
K. Chul Kim ◽  
Erik P. Lillehoj
Keyword(s):  
Epithelial Cells ◽  
Negative Control ◽  
Luciferase Reporter ◽  
Peroxisome Proliferator ◽  
Apical Surface ◽  
Gastric Epithelial Cells ◽  
Luciferase Reporter Gene ◽  
Ags Cells ◽  
Pparγ Agonist ◽  
H Pylori

MUC1 is a membrane-tethered mucin expressed on the apical surface of epithelial cells. Our previous report (Guang W, Ding H, Czinn SJ, Kim KC, Blanchard TG, Lillehoj EP. J Biol Chem 285: 20547–20557, 2010) demonstrated that expression of MUC1 in AGS gastric epithelial cells limits Helicobacter pylori infection and reduces bacterial-driven IL-8 production. In this study, we identified the peroxisome proliferator-associated receptor-γ (PPARγ) upstream of MUC1 in the anti-inflammatory pathway suppressing H. pylori- and phorbol 12-myristate 13-acetate (PMA)-stimulated IL-8 production. Treatment of AGS cells with H. pylori or PMA increased IL-8 levels in cell culture supernatants compared with cells treated with the respective vehicle controls. Prior small interfering (si)RNA-induced MUC1 silencing further increased H. pylori - and PMA-stimulated IL-8 levels compared with a negative control siRNA. MUC1-expressing AGS cells pretreated with the PPARγ agonist troglitazone (TGN) had reduced H. pylori - and PMA-stimulated IL-8 levels compared with cells treated with H. pylori or PMA alone. However, following MUC1 siRNA knockdown, no differences in IL-8 levels were seen between TGN/ H. pylori and H. pylori -only cells or between TGN/PMA and PMA-only cells. Finally, TGN-treated AGS cells had increased Muc1 promoter activity, as measured using a Muc1-luciferase reporter gene, and greater MUC1 protein levels by Western blot analysis, compared with vehicle controls. These results support the hypothesis that PPARγ stimulates MUC1 expression by AGS cells, thereby attenuating H. pylori - and PMA-induced IL-8 production.

scholarly journals Helicobacter pylori Induces Gastric Epithelial Cell Apoptosis in Association with Increased Fas Receptor Expression

1999 ◽  
Vol 67 (8) ◽  
pp. 4237-4242 ◽  
Author(s):  
Nicola L. Jones ◽  
Andrew S. Day ◽  
Hilary A. Jennings ◽  
Philip M. Sherman
Keyword(s):  
Cell Death ◽  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Receptor Expression ◽  
Gastric Epithelial Cells ◽  
Ags Cells ◽  
Fas Receptor ◽  
Epithelial Cell Apoptosis ◽  
H Pylori

ABSTRACT The mechanisms involved in mediating the enhanced gastric epithelial cell apoptosis observed during infection withHelicobacter pylori in vivo are unknown. To determine whether H. pylori directly induces apoptosis of gastric epithelial cells in vitro and to define the role of the Fas-Fas ligand signal transduction cascade, human gastric epithelial cells were infected with H. pylori for up to 72 h under microaerophilic conditions. As assessed by both transmission electron microscopy and fluorescence microscopy, incubation with acagA-positive, cagE-positive, VacA-positive clinical H. pylori isolate stimulated an increase in apoptosis compared to the apoptosis of untreated AGS cells (16.0% ± 2.8% versus 5.9% ± 1.4%, P < 0.05) after 72 h. In contrast, apoptosis was not detected following infection withcagA-negative, cagE-negative, VacA-negative clinical isolates or a Campylobacter jejuni strain. In addition to stimulating apoptosis, infection with H. pylorienhanced Fas receptor expression in AGS cells to a degree comparable to that of treatment with a positive control, gamma interferon (12.5 ng/ml) (148% ± 24% and 167% ± 24% of control, respectively). The enhanced Fas receptor expression was associated with increased sensitivity to Fas-mediated cell death. Ligation of the Fas receptor with an agonistic monoclonal antibody resulted in an increase in apoptosis compared to the apoptosis of cells infected with the bacterium alone (38.5% ± 7.1% versus 16.0% ± 2.8%,P < 0.05). Incubation with neutralizing anti-Fas antibody did not prevent apoptosis of H. pylori-infected cells. Taken together, these findings demonstrate that the gastric pathogen H. pylori stimulates apoptosis of gastric epithelial cells in vitro in association with the enhanced expression of the Fas receptor. These data indicate a role for Fas-mediated signaling in the programmed cell death that occurs in response toH. pylori infection.

Lactobacillus fermentum UCO-979C beneficially modulates the innate immune response triggered by Helicobacter pylori infection in vitro

2018 ◽  
Vol 9 (5) ◽  
pp. 829-841 ◽  
Author(s):  
V. Garcia-Castillo ◽  
H. Zelaya ◽  
A. Ilabaca ◽  
M. Espinoza-Monje ◽  
R. Komatsu ◽  
...  
Keyword(s):  
Immune Response ◽  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Morphological Changes ◽  
Helicobacter Pylori Infection ◽  
Lactobacillus Fermentum ◽  
Gastric Tissue ◽  
Gastric Epithelial Cells ◽  
Ags Cells ◽  
H Pylori

Helicobacter pylori infection is associated with important gastric pathologies. An aggressive proinflammatory immune response is generated in the gastric tissue infected with H. pylori, resulting in gastritis and a series of morphological changes that increase the susceptibility to cancer development. Probiotics could present an alternative solution to prevent or decrease H. pylori infection. Among them, the use of immunomodulatory lactic acid bacteria represents a promising option to reduce the severity of chronic inflammatory-mediated tissue damage and to improve protective immunity against H. pylori. We previously isolated Lactobacillus fermentum UCO-979C from human gastric tissue and demonstrated its capacity to reduce adhesion of H. pylori to human gastric epithelial cells (AGS cells). In this work, the ability of L. fermentum UCO-979C to modulate immune response in AGS cells and PMA phorbol 12-myristate 13-acetate (PMA)-differentiated THP-1 (human monocytic leukaemia) macrophages in response to H. pylori infection was evaluated. We demonstrated that the UCO-979C strain is able to differentially modulate the cytokine response of gastric epithelial cells and macrophages after H. pylori infection. Of note, L. fermentum UCO-979C was able to significantly reduce the production of inflammatory cytokines and chemokines in AGS and THP-1 cells as well as increase the levels of immunoregulatory cytokines, indicating a remarkable anti-inflammatory effect. These findings strongly support the probiotic potential of L. fermentum UCO-979C and provide evidence of its beneficial effects against the inflammatory damage induced by H. pylori infection. Although our findings should be proven in appropriate experiments in vivo, in both H. pylori infection animal models and human trials, the results of the present work provide a scientific rationale for the use of L. fermentum UCO-979C to prevent or reduce H. pylori-induced gastric inflammation in humans.

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