scholarly journals Differential Roles of ASK1 and TAK1 in Helicobacter pylori-Induced Cellular Responses

2013 ◽  
Vol 81 (12) ◽  
pp. 4551-4560 ◽  
Author(s):  
Yoku Hayakawa ◽  
Yoshihiro Hirata ◽  
Hiroto Kinoshita ◽  
Kosuke Sakitani ◽  
Hayato Nakagawa ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Signaling Pathway ◽  
Critical Role ◽  
Cellular Responses ◽  
Mapk Signaling ◽  
Dependent Manner ◽  
Content Type ◽  
H Pylori ◽  
Jnk Activation

ABSTRACTThe mitogen-activated protein kinase (MAPK) signaling pathway regulates various cellular functions, including those induced byHelicobacter pylori. TAK1 is an upstream MAPK kinase kinase (MAP3K) required forH. pylori-induced MAPK and NF-κB activation, but it remains unclear whether other MAP3Ks are involved inH. pylori-induced cellular responses. In this study, we focused on the MAP3K ASK1, which plays a critical role in gastric tumorigenesis. In gastric epithelial cells,H. pyloriactivates ASK1 in a reactive oxygen species (ROS)- andcagpathogenicity island-dependent manner, and ASK1 regulates sustained JNK activation and apoptosis induced byH. pylori. In contrast, TAK1 regulatesH. pylori-mediated early JNK activation and cytokine production. We also found reciprocal regulation between ASK1 and TAK1 inH. pylori-related responses, whereby inhibition of TAK1 or downstream p38 MAPK activates ASK1 through ROS production, and ASK1 suppresses TAK1 and downstream NF-κB activation. We identified ROS/ASK1/JNK as a new signaling pathway induced byH. pylori, which regulates apoptotic cell death. The balance of ASK1-induced apoptosis and TAK1-induced antiapoptotic or inflammatory responses may determine the fate of epithelial cells infected withH. pyloriand thus be involved in the pathogenesis of gastritis and gastric cancer.

scholarly journals Complex Cellular Responses of Helicobacter pylori-Colonized Gastric Adenocarcinoma Cells

2011 ◽  
Vol 79 (6) ◽  
pp. 2362-2371 ◽  
Author(s):  
Sabine Schneider ◽  
Gert Carra ◽  
Ugur Sahin ◽  
Benjamin Hoy ◽  
Gabriele Rieder ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Host Cell ◽  
Cell Lines ◽  
Molecular Mechanisms ◽  
Cellular Responses ◽  
Host Cells ◽  
Human Gastric Mucosa ◽  
Content Type ◽  
H Pylori

ABSTRACTHelicobacter pyloriis an important class I carcinogen that persistently infects the human gastric mucosa to induce gastritis, gastric ulceration, and gastric cancer.H. pyloripathogenesis strongly depends on pathogenic factors, such as VacA (vacuolating cytotoxin A) or a specialized type IV secretion system (T4SS), which injects the oncoprotein CagA (cytotoxin-associated gene A product) into the host cell. Since access to primary gastric epithelial cells is limited, many studies on the complex cellular and molecular mechanisms ofH. pyloriwere performed in immortalized epithelial cells originating from individual human adenocarcinomas. The aim of our study was a comparative analysis of 14 different human gastric epithelial cell lines after colonization withH. pylori. We found remarkable differences in host cell morphology, extent of CagA tyrosine phosphorylation, adhesion to host cells, vacuolization, and interleukin-8 (IL-8) secretion. These data might help in the selection of suitable cell lines to study host cell responses toH. pyloriin vitro, and they imply that different host cell factors are involved in the determination ofH. pyloripathogenesis. A better understanding ofH. pylori-directed cellular responses can provide novel and more balanced insights into the molecular mechanisms ofH. pylori-dependent pathogenesisin vivoand may lead to new therapeutic approaches.

scholarly journals The Helicobacter pylori Autotransporter ImaA (HP0289) Modulates the Immune Response and Contributes to Host Colonization

2012 ◽  
Vol 80 (7) ◽  
pp. 2286-2296 ◽  
Author(s):  
William E. Sause ◽  
Andrea R. Castillo ◽  
Karen M. Ottemann
Keyword(s):  
Immune Response ◽  
Helicobacter Pylori ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Dependent Manner ◽  
Wild Type ◽  
Content Type ◽  
H Pylori ◽  
Murine Infections

ABSTRACTThe human pathogenHelicobacter pyloriemploys a diverse collection of outer membrane proteins to colonize, persist, and drive disease within the acidic gastric environment. In this study, we sought to elucidate the function of the host-induced geneHP0289, which encodes an uncharacterized outer membrane protein. We first generated an isogenicH. pylorimutant that lacksHP0289and found that the mutant has a colonization defect in single-strain infections and is greatly outcompeted in mouse coinfection experiments with wild-typeH. pylori. Furthermore, we used protease assays and biochemical fractionation coupled with an HP0289-targeted peptide antibody to verify that the HP0289 protein resides in the outer membrane. Our previous findings showed that theHP0289promoter is upregulated in the mouse stomach, and here we demonstrate thatHP0289expression is induced under acidic conditions in an ArsRS-dependent manner. Finally, we have shown that theHP0289mutant induces greater expression of the chemokine interleukin-8 (IL-8) and the cytokine tumor necrosis factor alpha (TNF-α) in gastric carcinoma cells (AGS). Similarly, transcription of the IL-8 homolog keratinocyte-derived chemokine (KC) is elevated in murine infections with the HP0289 mutant than in murine infections with wild-typeH. pylori. On the basis of this phenotype, we renamed HP0289 ImaA forimmunomodulatoryautotransporter protein. Our work has revealed that genes inducedin vivoplay an important role inH. pyloripathogenesis. Specifically, the outer membrane protein ImaA modulates a component of the host inflammatory response, and thus may allowH. pylorito fine tune the host immune response based on ImaA expression.

scholarly journals Phosphothreonine Lyase Promotes p65 Degradation in a Mitogen-Activated Protein Kinase/Mitogen- and Stress-Activated Protein Kinase 1-Dependent Manner

2018 ◽  
Vol 87 (1) ◽  
Author(s):  
Mingyu Hou ◽  
Wenhui Wang ◽  
Feizi Hu ◽  
Yuanxing Zhang ◽  
Dahai Yang ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Pathogenic Bacteria ◽  
Critical Role ◽  
Nuclear Factor Κb ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Dependent Manner ◽  
Content Type ◽  
Catalytic Active Site ◽  
Mitogen Activated Protein

ABSTRACT Bacterial phosphothreonine lyases have been identified to be type III secretion system (T3SS) effectors that irreversibly dephosphorylate host mitogen-activated protein kinase (MAPK) signaling to promote infection. However, the effects of phosphothreonine lyase on nuclear factor κB (NF-κB) signaling remain largely unknown. In this study, we detected significant phosphothreonine lyase-dependent p65 degradation during Edwardsiella piscicida infection in macrophages, and this degradative effect was blocked by the protease inhibitor MG132. Further analysis revealed that phosphothreonine lyase promotes the dephosphorylation and ubiquitination of p65 by inhibiting the phosphorylation of mitogen- and stress-activated protein kinase-1 (MSK1) and by inhibiting the phosphorylation of extracellular signal-related kinase 1/2 (ERK1/2), p38α, and c-Jun N-terminal kinase (JNK). Moreover, we revealed that the catalytic active site of phosphothreonine lyase plays a critical role in regulating the MAPK-MSK1-p65 signaling axis. Collectively, the mechanism described here expands our understanding of the pathogenic effector in not only regulating MAPK signaling but also regulating p65. These findings uncover a new mechanism by which pathogenic bacteria overcome host innate immunity to promote pathogenesis.

scholarly journals Modification of the Gastric Mucosal Microbiota by a Strain-Specific Helicobacter pylori Oncoprotein and Carcinogenic Histologic Phenotype

mBio ◽  
2019 ◽  
Vol 10 (3) ◽  
Author(s):  
Jennifer M. Noto ◽  
Joseph P. Zackular ◽  
Matthew G. Varga ◽  
Alberto Delgado ◽  
Judith Romero-Gallo ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Helicobacter Pylori ◽  
Community Structure ◽  
Microbial Community ◽  
Iron Deficiency ◽  
Dependent Manner ◽  
Content Type ◽  
Β Diversity ◽  
H Pylori ◽  
Gastric Microbiota

ABSTRACT Helicobacter pylori is the strongest risk factor for gastric adenocarcinoma; however, most infected individuals never develop this malignancy. Strain-specific microbial factors, such as the oncoprotein CagA, as well as environmental conditions, such as iron deficiency, augment cancer risk. Importantly, dysbiosis of the gastric microbiota is also associated with gastric cancer. To investigate the combinatorial effects of these determinants in an in vivo model of gastric cancer, Mongolian gerbils were infected with the carcinogenic cag+ H. pylori strain 7.13 or a 7.13 cagA isogenic mutant, and microbial DNA extracted from gastric tissue was analyzed by 16S rRNA sequencing. Infection with H. pylori significantly increased gastric inflammation and injury, decreased α-diversity, and altered microbial community structure in a cagA-dependent manner. The effect of iron deficiency on gastric microbial communities was also investigated within the context of infection. H. pylori-induced injury was augmented under conditions of iron deficiency, but despite differences in gastric pathology, there were no significant differences in α- or β-diversity, phyla, or operational taxonomic unit (OTU) abundance among infected gerbils maintained on iron-replete or iron-depleted diets. However, when microbial composition was stratified based solely on the severity of histologic injury, significant differences in α- and β-diversity were present among gerbils harboring premalignant or malignant lesions compared to gerbils with gastritis alone. This study demonstrates that H. pylori decreases gastric microbial diversity and community structure in a cagA-dependent manner and that as carcinogenesis progresses, there are corresponding alterations in community structure that parallel the severity of disease. IMPORTANCE Microbial communities are essential for the maintenance of human health, and when these communities are altered, hosts can become susceptible to inflammation and disease. Dysbiosis contributes to gastrointestinal cancers, and specific bacterial species are associated with this phenotype. This study uses a robust and reproducible animal model to demonstrate that H. pylori infection induces gastric dysbiosis in a cagA-dependent manner and further that dysbiosis and altered microbial community structure parallel the severity of H. pylori-induced gastric injury. Ultimately, such models of H. pylori infection and cancer that can effectively evaluate multiple determinants simultaneously may yield effective strategies for manipulating the gastric microbiota to prevent the development of gastric cancer.

scholarly journals Helicobacter pylori induces intracellular galectin-8 aggregation around damaged lysosomes within gastric epithelial cells in a host O-glycan-dependent manner

Glycobiology ◽  
2018 ◽  
Vol 29 (2) ◽  
pp. 151-162 ◽  
Author(s):  
Fang-Yen Li ◽  
I-Chun Weng ◽  
Chun-Hung Lin ◽  
Mou-Chieh Kao ◽  
Ming-Shiang Wu ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Rhesus Macaques ◽  
Dependent Manner ◽  
Gastric Epithelial Cells ◽  
Vacuolating Cytotoxin ◽  
Infected Cells ◽  
H Pylori ◽  
Autophagy Activity ◽  
Binding Lectin

Abstract Galectin-8, a beta-galactoside-binding lectin, is upregulated in the gastric tissues of rhesus macaques infected with Helicobacter pylori. In this study, we found that H. pylori infection triggers intracellular galectin-8 aggregation in human-derived AGS gastric epithelial cells, and that these aggregates colocalize with lysosomes. Notably, this aggregation is markedly reduced following the attenuation of host O-glycan processing. This indicates that H. pylori infection induces lysosomal damage, which in turn results in the accumulation of cytosolic galectin-8 around damaged lysosomes through the recognition of exposed vacuolar host O-glycans. H. pylori-induced galectin-8 aggregates also colocalize with autophagosomes, and galectin-8 ablation reduces the activation of autophagy by H. pylori. This suggests that galectin-8 aggregates may enhance autophagy activity in infected cells. We also observed that both autophagy and NDP52, an autophagy adapter, contribute to the augmentation of galectin-8 aggregation by H. pylori. Additionally, vacuolating cytotoxin A, a secreted H. pylori cytotoxin, may contribute to the increased galectin-8 aggregation and elevated autophagy response in infected cells. Collectively, these results suggest that H. pylori promotes intracellular galectin-8 aggregation, and that galectin-8 aggregation and autophagy may reciprocally regulate each other during infection.

scholarly journals Phylogeographic Origin of Helicobacter pylori Determines Host-Adaptive Responses upon Coculture with Gastric Epithelial Cells

2013 ◽  
Vol 81 (7) ◽  
pp. 2468-2477 ◽  
Author(s):  
Alexander Sheh ◽  
Rupesh Chaturvedi ◽  
D. Scott Merrell ◽  
Pelayo Correa ◽  
Keith T. Wilson ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gastric Cancer ◽  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Gastric Disease ◽  
Gastric Epithelial Cells ◽  
Gastric Cancer Risk ◽  
Content Type ◽  
H Pylori ◽  
Induced Apoptosis

ABSTRACTWhileHelicobacter pyloriinfects over 50% of the world's population, the mechanisms involved in the development of gastric disease are not fully understood. Bacterial, host, and environmental factors play a role in disease outcome. To investigate the role of bacterial factors inH. pyloripathogenesis, global gene expression of sixH. pyloriisolates was analyzed during coculture with gastric epithelial cells. Clustering analysis of six Colombian clinical isolates from a region with low gastric cancer risk and a region with high gastric cancer risk segregated strains based on their phylogeographic origin. One hundred forty-six genes had increased expression in European strains, while 350 genes had increased expression in African strains. Differential expression was observed in genes associated with motility, pathogenicity, and other adaptations to the host environment. European strains had greater expression of the virulence factorscagA,vacA, andbabBand were associated with increased gastric histologic lesions in patients. In AGS cells, European strains promoted significantly higher interleukin-8 (IL-8) expression than did African strains. African strains significantly induced apoptosis, whereas only one European strain significantly induced apoptosis. Our data suggest that gene expression profiles of clinical isolates can discriminate strains by phylogeographic origin and that these profiles are associated with changes in expression of the proinflammatory and protumorigenic cytokine IL-8 and levels of apoptosis in host epithelial cells. These findings support the hypothesis that bacterial factors determined by the phylogeographic origin ofH. pyloristrains may promote increased gastric disease.

scholarly journals CagA Phosphorylation in Helicobacter pylori-Infected B Cells Is Mediated by the Nonreceptor Tyrosine Kinases of the Src and Abl Families

2016 ◽  
Vol 84 (9) ◽  
pp. 2671-2680 ◽  
Author(s):  
Linda M. Krisch ◽  
Gernot Posselt ◽  
Peter Hammerl ◽  
Silja Wessler
Keyword(s):  
Signal Transduction ◽  
Helicobacter Pylori ◽  
B Cells ◽  
Epithelial Cells ◽  
B Cell ◽  
Malt Lymphoma ◽  
Tyrosine Kinases ◽  
Signal Transduction Pathways ◽  
Content Type ◽  
H Pylori

CagA is one of the most important virulence factors of the human pathogenHelicobacter pylori. CagA expression can be associated with the induction of severe gastric disorders such as gastritis, ulceration, gastric cancer, or mucosa-associated lymphoid tissue (MALT) lymphoma. After translocation through a type IV secretion system into epithelial cells, CagA is tyrosine phosphorylated by kinases of the Src and Abl families, leading to drastic cell elongation and motility. While the functional role of CagA in epithelial cells is well investigated, knowledge about CagA phosphorylation and its associated signal transduction pathways in B cells is only marginal. Here, we established the B cell line MEC1 derived from a B cell chronic lymphocytic leukemia (B-CLL) patient as a new infection model to study the signal transduction in B cells controlled byH. pylori. We observed that CagA was rapidly injected, strongly tyrosine phosphorylated, and cleaved into a 100-kDa N-terminal and a 40-kDa C-terminal fragment. To identify upstream signal transduction pathways of CagA phosphorylation in MEC1 cells, pharmacological inhibitors were employed to specifically target Src and Abl kinases. We observed that CagA phosphorylation was strongly inhibited upon treatment with an Src inhibitor and slightly diminished when the Abl kinase inhibitor imatinib mesylate (Gleevec) was applied. The addition of dasatinib to block c-Abl and Src kinases led to a complete loss of CagA phosphorylation. In conclusion, these results demonstrate an important role for Src and Abl tyrosine kinases in CagA phosphorylation in B cells, which represent druggable targets inH. pylori-mediated gastric MALT lymphoma.

scholarly journals Ceramide and Toll-Like Receptor 4 Are Mobilized into Membrane Rafts in Response to Helicobacter pylori Infection in Gastric Epithelial Cells

2012 ◽  
Vol 80 (5) ◽  
pp. 1823-1833 ◽  
Author(s):  
Dah-Yuu Lu ◽  
Hui-Chen Chen ◽  
Mei-Shiang Yang ◽  
Yuan-Man Hsu ◽  
Hwai-Jeng Lin ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Lipid Rafts ◽  
Gastric Epithelial Cells ◽  
Toll Like Receptor ◽  
Tlr4 Expression ◽  
Ags Cells ◽  
Content Type ◽  
Infected Cells ◽  
H Pylori

ABSTRACTHelicobacter pyloriinfection is thought to be involved in the development of several gastric diseases. TwoH. pylorivirulence factors (vacuolating cytotoxin A and cytotoxin-associated gene A) reportedly interact with lipid rafts in gastric epithelial cells. The role of Toll-like receptor (TLR)-mediated signaling in response toH. pyloriinfection has been investigated extensively in host cells. However, the receptor molecules in lipid rafts that are involved inH. pylori-induced innate sensing have not been well characterized. This study investigated whether lipid rafts play a role inH. pylori-induced ceramide secretion and TLR4 expression and thereby contribute to inflammation in gastric epithelial cells. We observed that both TLR4 and MD-2 mRNA and protein levels were significantly higher inH. pylori-infected AGS cells than in mock-infected cells. Moreover, significantly more TLR4 protein was detected in detergent-resistant membranes extracted fromH. pylori-infected AGS cells than in those extracted from mock-infected cells. However, this effect was attenuated by the treatment of cells with cholesterol-usurping agents, suggesting thatH. pylori-induced TLR4 signaling is dependent on cholesterol-rich microdomains. Similarly, the level of cellular ceramide was elevated and ceramide was translocated into lipid rafts afterH. pyloriinfection, leading to interleukin-8 (IL-8) production. Using the sphingomyelinase inhibitor imipramine, we observed thatH. pylori-induced TLR4 expression was ceramide dependent. These results indicate the mobilization of ceramide and TLR4 into lipid rafts byH. pyloriinfection in response to inflammation in gastric epithelial cells.

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 and Epstein-Barr Virus Coinfection Stimulates Aggressiveness in Gastric Cancer through the Regulation of Gankyrin

mSphere ◽  
2021 ◽  
Author(s):  
Dharmendra Kashyap ◽  
Budhadev Baral ◽  
Shweta Jakhmola ◽  
Anil Kumar Singh ◽  
Hem Chandra Jha
Keyword(s):  
Gastric Cancer ◽  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Epstein Barr Virus ◽  
Synergistic Effects ◽  
Gastric Epithelial Cells ◽  
Content Type ◽  
Barr Virus ◽  
Epstein Barr ◽  
H Pylori

In the present study, we evaluated the synergistic effects of EBV and H. pylori infection on gastric epithelial cells in various coinfection models. These coinfection models were among the first to depict the exposures of gastric epithelial cells to EBV followed by H. pylori ; however, coinfection models exist that narrated the scenario upon exposure to H. pylori followed by that to EBV.

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