Helicobacter pylori infection activates NF-κB signaling pathway to induce iNOS and protect human gastric epithelial cells from apoptosis

2003 ◽  
Vol 285 (6) ◽  
pp. G1171-G1180 ◽  
Author(s):  
Jung Mogg Kim ◽  
Joo Sung Kim ◽  
Hyun Chae Jung ◽  
Yu-Kyoung Oh ◽  
Hee-Young Chung ◽  
...  

Helicobacter pylori infection induces apoptosis and inducible nitric oxide synthase (iNOS) expression in gastric epithelial cells. In this study, we investigated the effects of NF-κB activation and iNOS expression on apoptosis in H. pylori-infected gastric epithelial cells. The suppression of NF-κB significantly increased caspase-3 activity and apoptosis in H. pylori-infected MKN-45 and Hs746T gastric epithelial cell lines as well as primary gastric epithelial cells. An NF-κB signaling pathway via NF-κB-inducing kinase and IκB kinase-β activation was found to be involved in the inhibition of apoptosis in H. pylori-infected gastric epithelial cells. In gastric epithelial cells transfected with retrovirus containing IκBα superrepressor, iNOS mRNA and protein levels were reduced, indicating that H. pylori infection induced the expression of iNOS by activating NF-κB. Moreover, a NO donor, S-nitroso- N-acetylpenicillamine (100 μM), decreased caspase-3 activity and apoptosis in NF-κB-suppressed cells infected with H. pylori. These results suggest that NF-κB activation may play a role in protecting gastric epithelial cells from H. pylori-induced apoptosis by upregulating endogenous iNOS.

2018 ◽  
Vol 9 (5) ◽  
pp. 829-841 ◽  
Author(s):  
V. Garcia-Castillo ◽  
H. Zelaya ◽  
A. Ilabaca ◽  
M. Espinoza-Monje ◽  
R. Komatsu ◽  
...  

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.


PLoS ONE ◽  
2019 ◽  
Vol 14 (8) ◽  
pp. e0220636 ◽  
Author(s):  
Weronika Gonciarz ◽  
Agnieszka Krupa ◽  
Krzysztof Hinc ◽  
Michał Obuchowski ◽  
Anthony P Moran ◽  
...  

2011 ◽  
Vol 135 (6) ◽  
pp. 759-765
Author(s):  
So-Hyun Shin ◽  
Seog-Yun Park ◽  
Jae-Sung Ko ◽  
Nayoung Kim ◽  
Gyeong Hoon Kang

Abstract Context.—Helicobacter pylori infection is primarily acquired during childhood and persists throughout life in the absence of eradication with antibiotics. Helicobacter pylori infection induces methylation in the promoter CpG island loci in gastric epithelial cells. Thus, aberrant CpG island hypermethylation in gastric epithelial cells likely occurs early in life, although there are no existing data supporting this notion. Objectives.—To identify whether aberrant CpG island hypermethylation occurs in pediatric stomach mucosa in association with H pylori infection and to compare methylation profiles of samples from pediatric and adult stomach tissues. Design.—We analyzed pediatric (n  =  47) and adult (n  =  38) gastric mucosa samples for their methylation status in 12 promoter CpG island loci using the MethyLight assay and compared the number of methylated genes and the methylation levels in individual genes between H pylori–positive and H pylori–negative sample results and between pediatric and adult samples. Results.—The average number of methylated genes was significantly higher in H pylori–infected pediatric samples than in H pylori–negative pediatric samples (3.4 versus 0.3, P < .001) and in H pylori–infected adult samples than in H pylori–negative adult samples (7.6 versus 0.9, P < .001). Seven genes showed significantly higher methylation levels in H pylori–infected pediatric samples than in H pylori–negative pediatric samples (all values were P < .05). Conclusions.—These results indicate that CpG island hypermethylation occurs in pediatric gastric mucosa in association with H pylori infection and that the genes affected by H pylori–associated hypermethylation were similar in pediatric and adult samples.


2000 ◽  
Vol 118 (4) ◽  
pp. A26
Author(s):  
Masaaki Shimada ◽  
Kenji Ina ◽  
Takafumi Ando ◽  
Akira Imada ◽  
Yuji Nishio ◽  
...  

Nutrients ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 4281
Author(s):  
Suhn Hyung Kim ◽  
Hyeyoung Kim

Helicobacter pylori (H. pylori) infection promotes gastric carcinogenesis by increasing oxidative stress, inflammation, and dysregulation of cell survival and proliferation of gastric epithelial cells. Astaxanthin (ASTX), a bioactive carotenoid, exhibits antioxidant and anticancer effects by modulating aberrant signaling pathways that lead to dysregulation of cell death and proliferation. To elucidate the molecular mechanism of H. pylori-induced gastric carcinogenesis and to examine the inhibitory effect of ASTX on H. pylori-induced gastric epithelial cell gene expression changes, we performed comparative RNA-sequencing (RNA-Seq) analysis for H. pylori-infected gastric epithelial cells treated with or without ASTX. RNA-Seq results reveal that differentially expressed genes (DEGs) in H. pylori-infected cells were mainly associated with the Wnt/β-catenin signaling pathway, which is related to cell proliferation. ASTX significantly reversed H. pylori-induced transcriptional alterations of the key mediators involved in β-catenin signaling, notably, porcupine (gene symbol, PORCN), spermine oxidase (SMOX), bone morphogenetic protein (BMP) and activin membrane-bound inhibitor (BAMBI), SMAD family member 4 (SMAD4), transforming growth factor-β1 (TGFB1), Fos-like 1 (FOSLI), and c-myc (MYC). We suggest that ASTX may be a potential therapeutic agent that can suppress H. pylori-induced proliferation-associated gene expression changes, in part, by counter-regulating the Wnt/β-catenin signaling pathway.


2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Liping Tao ◽  
Hai Zou ◽  
Zhimin Huang

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.


mBio ◽  
2017 ◽  
Vol 8 (4) ◽  
Author(s):  
Alevtina Gall ◽  
Ryan G. Gaudet ◽  
Scott D. Gray-Owen ◽  
Nina R. Salama

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.


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