Helicobacter Pylori-infected Cells Research Articles

Helicobacter pylori Outer Membrane Vesicles and Extracellular Vesicles from Helicobacter pylori-Infected Cells in Gastric Disease Development.

Extracellular vesicles (EVs) are cell-derived vesicles important in intercellular communication that play an essential role in host-pathogen interactions, spreading pathogen-derived as well as host-derived molecules during infection. Pathogens can induce changes in the composition of EVs derived from the infected cells and use them to manipulate their microenvironment and, for instance, modulate innate and adaptive inflammatory immune responses, both in a stimulatory or suppressive manner. Gastric cancer is one of the leading causes of cancer-related deaths worldwide and infection with Helicobacter pylori (H. pylori) is considered the main risk factor for developing this disease, which is characterized by a strong inflammatory component. EVs released by host cells infected with H. pylori contribute significantly to inflammation, and in doing so promote the development of disease. Additionally, H. pylori liberates vesicles, called outer membrane vesicles (H. pylori-OMVs), which contribute to atrophia and cell transformation in the gastric epithelium. In this review, the participation of both EVs from cells infected with H. pylori and H. pylori-OMVs associated with the development of gastric cancer will be discussed. By deciphering which functions of these external vesicles during H. pylori infection benefit the host or the pathogen, novel treatment strategies may become available to prevent disease.

Transcriptome profiling analysis of the response to walnut polyphenol extract in Helicobacter pylori-infected cells.

Dietary intervention to prevent Helicobacter pylori (H. pylori)-associated gastric diseases seems to be ideal with no risk of bacterial resistance, safe long-term intervention, and correcting pathogenic mechanisms including rejuvenation of precancerous atrophic gastritis and anti-mutagenesis. A transcriptome as set of all RNAs transcribed by certain tissues or cells demonstrates gene functions and reveals the molecular mechanism of specific biological processes against diseases. Here, we have performed RNAseq and bioinformatic analysis to explain proof of concept that walnut intake can rescue from H. pylori infection and explore unidentified mode of actions of walnut polyphenol extract (WPE). As results, BIRC3, SLC25A4, f3 transcription, VEGFA, AZU1, HMOX1, RAB3A, RELBTNIP1, ETFB, INPP5J, PPME1, RHOB, TPI1, FOSL1, JUND.RELB, KLF2, MUC1, NDRG1, ALDOA, ENO1, PFKP, GPI, GDF15, and NRTN genes were newly discovered to be enriched with WPE, whereas CCR4, BLNK, CCR7, CXCR4, CDO1, KLSG1, SELE, RASGRP2, PIK3R3, TSPAN32, HOXC-AS3, HCG8, BTNL8, and CXCL3 genes as inhibitory targets by WPE in H. pylori infection. We identified additional genes what WPE afforded actions of avoiding H. pylori-driven onco-inflammation and rejuvenating precancerous atrophic gastritis. Conclusively, after applying RNAseq analysis in order to document walnut intake for precision medicine against H. pylori infection, significant transcriptomic profiling applicable for validation were drawn.

The inhibition of Helicobacter pylori infected cells by Origanum minutiflorum

This study aimed to investigate the potential use of Origanum minutiflorum for the eradication of Helicobacter pylori by determining antimicrobial activity, minimum bactericidal concentration (MBC), and chemical composition of its essential oil (EO). Furthermore, cell cytotoxicity and anti-H. pylori action of EO on AGS/H. pylori infected cells were also determined. Essential oil extracts displayed a strong antimicrobial activity against H. pylori. Carvacrol (29.22%), a known antimicrobial agent, was observed as the predominant compound. The MBC (1/20,000 v/v) of EO was nontoxic to AGS cells, revealing a >80% reduction. Moreover, EO at the same concentration displayed the ability to kill H. pylori in/on infected cells. The findings of this study demonstrated the positive antimicrobial and anti-adherence/anti-invasion effect of O. minutiflorum EO extract for the eradication of H. pylori and H. pylori infected AGS cells.

Differential Role of ERK and p38 on NF- κ B Activation in Helicobacter pylori-Infected Gastric Epithelial Cells.

Gastric cancer, as well as inflammation, caused by Helicobacter pylori, activates the production of chemokines by activation of redox-sensitive transcription factor NF-κB in gastric epithelial cells. Mitogen-activated protein kinases including extracellular signal-regulated kinase (ERK) and p38 kinase (p38) are activated by Helicobacter pylori, which may regulate NF-κB activation in the infected cells. However the mechanisms how ERK and p38 induce NF-κB activation have not been investigated. Present study aims to investigate the role of ERK and p38 on the activation of NF-κB in Helicobacter pylori-infected AGS cells. Western blot analysis was performed for determining the levels of IκB, p105, p50 and p65 in gastric epithelial cells infected with Helicobacter pylori and treated with ERK inhibitor U0126 and p38 inhibitor SB203580. Helicobacter pylori induced the degradation of IκBα and upregulation of p105, p50 and p65 in the infected cells. U0126 inhibited the degradation of IκBα while SB203580 suppressed expression of p105, p50 and p65 in Helicobacter pylori-infected cells. ERK and p38 differentially activate NF-κB; ERK induces degradation of IκBα while p38 upregulates the expression of p50 and p65, subunits of NF-κB in Helicobacter pylori-infected gastric epithelial AGS cells.

Red ginseng extract inhibits the expression of MCP-1 and iNOS in Helicobacter pylori-infected gastric epithelial cells by suppressing the activation of NADPH oxidase and Jak2/Stat3

Ethnopharmcological relevanceHelicobacter pylori induced oxidative stress represents an important mechanism leading to expression of inflammatory mediators. Korean red ginseng is used in traditional medicine to inhibit inflammation. However, the anti-inflammatory mechanism of red ginseng is still under investigation. Thus, we investigated whether Korean red ginseng extract (RGE) inhibits NADPH oxidase, a source of reactive oxygen species (ROS), and the Jak2/Stat3 pathway, which mediates the expression of inflammatory mediators, in Helicobacter pylori-infected gastric epithelial cells. Materials and methodsA standardized RGE was supplied by the Korea Ginseng Corporation. Human gastric epithelial cells (AGS) were treated with RGE and stimulated with Helicobacter pylori. NADPH oxidase activity, ROS levels, activation of Jak2/Stat3, and induction of MCP-1 and iNOS were determined. ResultsHelicobacter pylori infection resulted in an increase in ROS and activation of NADPH oxidase and Jak2/Stat3, which induced the expression of MCP-1 and iNOS in AGS cells. The induction of MCP-1 and iNOS was inhibited by both the Jak2/Stat3 inhibitor AG490 and RGE in Helicobacter pylori-infected cells. RGE suppressed NADPH oxidase activity by inhibiting translocation of cytosolic subunits p67phox and p47phox to the membrane and reduced ROS levels in Helicobacter pylori-infected cells. ConclusionRGE inhibits the expression of MCP-1 and iNOS by suppressing the activation of NADPH oxidase and Jak2/Stat3 in Helicobacter pylori-infected gastric epithelial cells.

Anti-inflammatory and cytoprotective effects of selected Pakistani medicinal plants in Helicobacter pylori-infected gastric epithelial cells

Ethnopharmacological relevanceHelicobacter pylori infection is associated with gastritis, peptic ulcer, and gastric cancer. Due to its high global prevalence and uprising resistance to available antibiotics, efforts are now directed to identify alternative source to treat and prevent associated disorders. In the present study, effect of selected indigenous medicinal plants of Pakistan was evaluated on the secretion of interleukin-8 (IL-8) and generation of reactive oxygen species (ROS) in a bid to rationalize their medicinal use and to examine the anti-inflammatory and cytoprotective effects in gastric epithelial cells. Materials and methodsAGS cells and clinically isolated Helicobacter pylori strain (193C) were employed for co-culture experiments. Anti-Helicobacter pylori activity and cytotoxic effects of the selected plants were determined by serial dilution method and DNA fragmentation assay respectively. ELISA and flow cytometry were performed to evaluate the effect on IL-8 secretion and ROS generation in Helicobacter pylori-infected cells. ResultsAt 100μg/ml, extracts of Alpinia galangal, Cinnamomum cassia, Cinnamomum tamala, Mentha arvensis, Myrtus communis, Oligochaeta ramose, Polygonum bistorta, Rosa damascena, Ruta graveolens, Syzygium aromaticum, Tamarix dioica, and Terminalia chebula exhibited strong inhibitory activity against IL-8 secretion. Of these, four extracts of Cinnamomum cassia, Myrtus communis, Syzygium aromaticum, and Terminalia chebula markedly inhibited IL-8 secretion at both 50 and 100μg/ml. Cinnamomum cassia was further assessed at different concentrations against Helicobacter pylori and TNF-α stimulated IL-8 secretion, which displayed significant suppression of IL-8 in a concentration-dependent-manner. Among the plants examined against ROS generation, Achillea millefolium, Berberis aristata, Coriandrum sativum, Foeniculum vulgare, Matricaria chamomilla and Prunus domestica demonstrated significant suppression of ROS from Helicobacter pylori-infected cells (p<0.01). ConclusionResults of the study revealed anti-inflammatory and cytoprotective effects of selected medicinal plants which could partially validate the traditional use of these plants in GI disorders particularly associated with Helicobacter pylori. Furthermore, results obtained may lead to possible future candidates of chemoprevention against peptic ulcer or gastric cancer.

P0516 HELICOBACTER PYLORI EXPRESS AN E2A HOMOLOGUE?

Introduction: Previously, we have shown that Helicobacter pylori can regulate acutely the expression of Id helix-loop-helix transcriptional regulators, at both mRNA and protein level. Specifically, Id-1 and Id-3 were down regulated two to twenty-four hours after exposure of gastric epithelial cells to Helicobacter pylori. Consequently, we hypothesised that the transcriptional activity of their ubiquitously expressed partner protein, E2A (E47/E12), would be increased. Methods: AGS gastric epithelial cells were infected with the wild-type Helicobacter pylori strain 60190, at a multiplicity of infection ratio of 1:100. Cells were incubated with bacteria for up to 24 hours. At set times, cells were harvested and protein and RNA were isolated according to standard methods. Western blotting and RT-PCR were used to determine protein and RNA levels respectively. For immunofluorescence studies, cells were grown on glass coverslips and fixed in acetone/methanol prior to antibody labelling. Electrophoretic mobility shift assay was used to determine E-Box binding activity in cell lysates using a probe based on the E-box binding site from immunoglobulin heavychain enhancer region. Results: Western blotting showed increased E2A expression with time in untreated cells. This was not seen in Helicobacter pylori-infected cells, although Western blotting showed induction of a strongly immunoreactive band of slightly lower apparent molecular weight than E47/E12. E2A mRNA expression was also analysed using RT-PCR, but levels remained constant over 24 hours in the absence or presence of Helicobacter pylori. These data suggested that E47/E12 was regulated post-transcriptionally. Despite the large increase in the expression of a protein of similar size to E47/E12, the level of E-Box binding activity was reduced in Helicobacter pylori-treated cells, as determined by electrophoretic mobility shift assay. Immunofluorescence studies identified the subcellular localisation of E2A immunoreactivity, with very strong immunoreactivity associated with the bacteria. Western blotting was used to confirm the presence, in Helicobacter pylori cell lysates, of an E2A cross-reactive protein of an identical size to the strongly induced protein in the gastric epithelial cells. Conclusion:Helicobacter pylori infection prevented accumulation of E2A expression in gastric epithelial cells by a post-transcriptional mechanism, which was associated with decreased E-Box binding activity. However, data showed that Helicobacter pylori express an E2A-related protein. We hypothesise this protein functions to regulate gene expression in infected cells, and may be injected into the host cell by the bacterium.