scholarly journals CagA Effector Protein in Helicobacter pylori-Infected Human Gastric Epithelium in Vivo: From Bacterial Core and Adhesion/Injection Clusters to Host Cell Proteasome-Rich Cytosol

Toxins ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 618 ◽  
Author(s):  
Vittorio Necchi ◽  
Vittorio Ricci ◽  
Patrizia Sommi ◽  
Enrico Solcia
Keyword(s):  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Host Cell ◽  
Experimental Studies ◽  
Intracellular Distribution ◽  
Gastric Epithelium ◽  
Effector Protein ◽  
H Pylori

A key role in the carcinogenic action of Helicobacter pylori is played by the effector protein CagA, the first identified oncoprotein of the bacterial world. However, the present knowledge in regard to the bacterial injection of CagA into epithelial cells (through a type IV secretion system) and its intracellular fate is based primarily on experimental studies in vitro. Our study was aimed to investigate, in H. pylori-infected human gastric epithelium, CagA delivery and intracellular distribution in order to identify any in vivo counterpart of the cell injection mechanism described in vitro and any intracellular cytoplasmic site of preferential CagA distribution, thus shedding light on the natural history of CagA in vivo. By transmission electron microscopy and ultrastructural immunocytochemistry (which combine precise molecule localization with detailed analysis of bacterial-host cell interaction and epithelial cell ultrastructure), we investigated endoscopic biopsies of gastric antrum from H. pylori-infected dyspeptic patients. Our findings provide support for CagA direct injection into gastric epithelial cells at bacterial adhesion sites located on the lateral plasma membrane and for its cytosolic intracellular distribution with selective concentration inside peculiar proteasome-rich areas, which might be site not only of CagA degradation but also of CagA-promoted crucial events in gastric carcinogenesis.

scholarly journals Helicobacter pylori Colonization Drives Urokinase Receptor (uPAR) Expression in Murine Gastric Epithelium During Early Pathogenesis

2020 ◽  
Vol 8 (7) ◽  
pp. 1019
Author(s):  
Warner Alpízar-Alpízar ◽  
Mette E. Skindersoe ◽  
Lone Rasmussen ◽  
Mette C. Kriegbaum ◽  
Ib J. Christensen ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Protein Expression ◽  
De Novo ◽  
Urokinase Receptor ◽  
Gastric Epithelium ◽  
Upar Expression ◽  
H Pylori

(1) Background: Persistent Helicobacter pylori infection is the most important risk factor for gastric cancer. The urokinase receptor (uPAR) is upregulated in lesions harboring cancer invasion and inflammation. Circumstantial evidence tends to correlate H. pylori colonization with increased uPAR expression in the human gastric epithelium, but a direct causative link has not yet been established in vivo; (2) Methods: In a mouse model of H. pylori-induced gastritis, we investigated the temporal emergence of uPAR protein expression in the gastric mucosa in response to H. pylori (SS1 strain) infection; (3) Results: We observed intense uPAR immunoreactivity in foveolar epithelial cells of the gastric corpus due to de novo synthesis, compared to non-infected animals. This uPAR induction represents a very early response, but it increases progressively over time as do infiltrating immune cells. Eradication of H. pylori infection by antimicrobial therapy causes a regression of uPAR expression to its physiological baseline levels. Suppression of the inflammatory response by prostaglandin E2 treatment attenuates uPAR expression. Notwithstanding this relationship, H. pylori does induce uPAR expression in vitro in co-cultures with gastric cancer cell lines; (4) Conclusions: We showed that persistent H. pylori colonization is a necessary event for the emergence of a relatively high uPAR protein expression in murine gastric epithelial cells.

scholarly journals Limited Role of Lipopolysaccharide Lewis Antigens in Adherence of Helicobacter pylori to the Human Gastric Epithelium

2003 ◽  
Vol 71 (5) ◽  
pp. 2876-2880 ◽  
Author(s):  
Jafar Mahdavi ◽  
Thomas Borén ◽  
Christina Vandenbroucke-Grauls ◽  
Ben J. Appelmelk
Keyword(s):  
Helicobacter Pylori ◽  
Gastric Epithelium ◽  
In Vivo Studies ◽  
Minor Role ◽  
Human Gastric Mucosa ◽  
H Pylori

ABSTRACT In vitro and in vivo studies from various groups have suggested that Helicobacter pylori lipopolysaccharide (LPS) Lewis x (Lex) antigens mediate bacterial adhesion. We have now reevaluated this hypothesis by studying the adherence in situ of H. pylori strain 11637 and its corresponding Lex-negative rfbM mutant to human gastric mucosa from patients (n = 22) with various gastric pathologies. Significant binding of the parent strain was observed in only 8 out of 22 sections; in four out of eight patients, the Lex-negative mutant bound less well. One of these four patients displayed no gastric abnormalities, and the other three showed dysplasia, metaplasia, and adenocarcinoma, respectively; hence, we are unable to define the circumstances under which LPS-mediated adhesion takes place. We conclude that H. pylori LPS plays a distinct but minor role in adhesion.

scholarly journals Regulation of Human β-Defensins by Gastric Epithelial Cells in Response to Infection with Helicobacter pylori or Stimulation with Interleukin-1

2000 ◽  
Vol 68 (9) ◽  
pp. 5412-5415 ◽  
Author(s):  
Deborah A. O'Neil ◽  
Sheri P. Cole ◽  
Edith Martin-Porter ◽  
Michael P. Housley ◽  
Lide Liu ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Interleukin 1 ◽  
Peptide Antibiotic ◽  
Gastric Epithelial Cells ◽  
Proinflammatory Mediators ◽  
H Pylori

ABSTRACT Gastric epithelial cells in vitro and in vivo are shown to constitutively express the peptide antibiotic human β-defensin type 1 (hBD-1). In contrast, hBD-2 expression is regulated in gastric epithelial cells and increases in response to infection withHelicobacter pylori or stimulation with the proinflammatory cytokine interleukin-1. These data suggest that hBD-2 is a component of the regulated host gastric epithelial cell response to H. pylori infection and proinflammatory mediators.

scholarly journals Helicobacter pylori Chemotaxis Modulates Inflammation and Bacterium-Gastric Epithelium Interactions in Infected Mice

2007 ◽  
Vol 75 (8) ◽  
pp. 3747-3757 ◽  
Author(s):  
Susan M. Williams ◽  
Yu-Ting Chen ◽  
Tessa M. Andermann ◽  
J. Elliot Carter ◽  
David J. McGee ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Gastric Epithelium ◽  
Wild Type ◽  
Intimate Association ◽  
Directed Motility ◽  
Chemotaxis Receptors ◽  
H Pylori ◽  
Stomach Epithelium

ABSTRACT The ulcer-causing pathogen Helicobacter pylori uses directed motility, or chemotaxis, to both colonize the stomach and promote disease development. Previous work showed that mutants lacking the TlpB chemoreceptor, one of the receptors predicted to drive chemotaxis, led to less inflammation in the gerbil stomach than did the wild type. Here we expanded these findings and examined the effects on inflammation of completely nonchemotactic mutants and mutants lacking each chemoreceptor. Of note, all mutants colonized mice to the same levels as did wild-type H. pylori. Infection by completely nonchemotactic mutants (cheW or cheY) resulted in significantly less inflammation after both 3 and 6 months of infection. Mutants lacking either the TlpA or TlpB H. pylori chemotaxis receptors also had alterations in inflammation severity, while mutants lacking either of the other two chemoreceptors (TlpC and HylB) behaved like the wild type. Fully nonchemotactic and chemoreceptor mutants adhered to cultured gastric epithelial cells and caused cellular release of the chemokine interleukin-8 in vitro similar to the release caused by the wild type. The situation appeared to be different in the stomach. Using silver-stained histological sections, we found that nonchemotactic cheY or cheW mutants were less likely than the wild type to be intimately associated with the cells of the gastric mucosa, although there was not a strict correlation between intimate association and inflammation. Because others have shown that in vivo adherence promotes inflammation, we propose a model in which H. pylori uses chemotaxis to guide it to a productive interaction with the stomach epithelium.

scholarly journals Helicobacter pylori-induced Rev-erbα fosters gastric bacterial colonization by impairing host innate and adaptive defense

2020 ◽  
Author(s):  
Yuan Zhuang ◽  
Fangyuan Mao ◽  
Yipin Lv ◽  
Chuanjie Hao ◽  
Yongsheng Teng ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Gastric Mucosa ◽  
Bacterial Colonization ◽  
Direct Consequence ◽  
Gastric Epithelium ◽  
Th1 Cell ◽  
Extracellular Signal ◽  
H Pylori

Abstract Background: Helicobacter pylori (H. pylori) is a human pathogen that infects nearly half of the world’s population, however, the persistent colonization of H. pylori in gastric mucosa remains poorly understood. Nowadays it is believed that impairment of host defense of gastric epithelium induced by H. pylori plays key roles in H. pylori-associated pathology. The nuclear receptor Rev-erbα represents a powerful transcriptional repressor involved in host immunity. However, the regulation, function, and clinical relevance of Rev-erbα in H. pylori infection are presently unknown. Here we demonstrated a pro-colonization role of Rev-erbα in H. pylori infection.Results: Rev-erbα was increased in gastric mucosa of H. pylori-infected patients and mice. H. pylori induced gastric epithelial cells (GECs) to express Rev-erbα via the phosphorylated cagA that activated extracellular signal-regulated kinase (ERK) signaling pathway to mediate transcription factor nuclear factor kappa-B (NF-κB) directly binding to Rev-erbα promoter. Human gastric Rev-erbα expression correlated with H. pylori colonization, and mouse Rev-erbα from non-bone marrow-derived cells promoted gastric H. pylori burden. Importantly, H. pylori colonization was attenuated in Rev-erbα-/- mice and the mice with in vivo pharmacological inhibition of Rev-erbα. Mechanistically, Rev-erbα in GECs not only directly suppressed Reg3b and β-defensin-1 expression via binding to Reg3b and β-defensin-1 promoter respectively, which resulted in impaired bactericidal effects against H. pylori of these antibacterial proteins in vitro and in vivo; but also directly inhibited chemokine CCL21 expression via binding to CCL21 promoter, which led to decreased gastric influx of CD45+CD11c-Ly6G-CD11b+CD68- myeloid cells by CCL21-CCR7-dependent migration and, as a direct consequence, reduced bacterial clearing capacity of H. pylori-specific T helper type 1 (Th1) cell response. Conclusions: Overall, this study identifies a model involving Rev-erbα, which collectively ensures gastric bacterial persistence by suppressing host gene expression required for local innate and adaptive defense against H. pylori, and also highlight a pathological role and an immunosuppressive mechanism of Rev-erbα in persistent H. pylori infection.

scholarly journals Adherence ofHelicobacter pylorito the Gastric Mucosa

1997 ◽  
Vol 11 (3) ◽  
pp. 243-248 ◽  
Author(s):  
Marguerite Clyne ◽  
Brendan Drumm
Keyword(s):  
Helicobacter Pylori ◽  
Gastric Mucosa ◽  
Bacterial Adhesion ◽  
Initial Step ◽  
Gastric Epithelium ◽  
In Vivo Models ◽  
Enteric Diseases ◽  
H Pylori

Bacterial adhesion to the intestinal epithelium is a critical initial step in the pathogenesis of many enteric diseases.Helicobacter pyloriis a duodenal pathogen that adheres to the gastric epithelium and causes gastritis and peptic ulceration. The mechanism by whichH pyloricauses disease has not yet been elucidated but adherence to the gastric mucosa is thought to be an important virulence determinant of the organism. What is known about adherence ofH pylorito the gastric mucosa is summarized. Topics discussed are the mechanism ofH pyloriadherence; in vitro and in vivo models ofH pyloriinfection; and adherence and potential adhesins and receptors forH pylori.

scholarly journals Nutrient Deficiency Promotes the Entry of Helicobacter pylori Cells into Candida Yeast Cells

Biology ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 426
Author(s):  
Kimberly Sánchez-Alonzo ◽  
Fabiola Silva-Mieres ◽  
Luciano Arellano-Arriagada ◽  
Cristian Parra-Sepúlveda ◽  
Humberto Bernasconi ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Nutrient Deficiency ◽  
Gastric Epithelium ◽  
Yeast Cells ◽  
Nutrient Concentrations ◽  
Fetal Bovine ◽  
H Pylori ◽  
Pcr Techniques ◽  
Strain Dependent

Helicobacter pylori, a Gram-negative bacterium, has as a natural niche the human gastric epithelium. This pathogen has been reported to enter into Candida yeast cells; however, factors triggering this endosymbiotic relationship remain unknown. The aim of this work was to evaluate in vitro if variations in nutrient concentration in the cultured medium trigger the internalization of H. pylori within Candida cells. We used H. pylori–Candida co-cultures in Brucella broth supplemented with 1%, 5% or 20% fetal bovine serum or in saline solution. Intra-yeast bacteria-like bodies (BLBs) were observed using optical microscopy, while intra-yeast BLBs were identified as H. pylori using FISH and PCR techniques. Intra-yeast H. pylori (BLBs) viability was confirmed using the LIVE/DEAD BacLight Bacterial Viability kit. Intra-yeast H. pylori was present in all combinations of bacteria–yeast strains co-cultured. However, the percentages of yeast cells harboring bacteria (Y-BLBs) varied according to nutrient concentrations and also were strain-dependent. In conclusion, reduced nutrients stresses H. pylori, promoting its entry into Candida cells. The starvation of both H. pylori and Candida strains reduced the percentages of Y-BLBs, suggesting that starving yeast cells may be less capable of harboring stressed H. pylori cells. Moreover, the endosymbiotic relationship between H. pylori and Candida is dependent on the strains co-cultured.

Enhanced fitness of a Helicobacter pylori babA mutant in a murine model

2021 ◽  
Author(s):  
M. Lorena Harvey ◽  
Aung Soe Lin ◽  
Lili Sun ◽  
Tatsuki Koyama ◽  
Jennifer H. B. Shuman ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Outer Membrane Proteins ◽  
Population Diversity ◽  
Fitness Advantage ◽  
Neutral Locus ◽  
Mutant Strains ◽  
Bacterial Fitness ◽  
H Pylori

Helicobacter pylori genomes encode >60 predicted outer membrane proteins (OMPs). Several OMPs in the Hop family act as adhesins, but the functions of most Hop proteins are unknown. To identify hop mutant strains that exhibit altered fitness in vivo compared to fitness in vitro , we used a genetic barcoding method that allowed us to track changes in the proportional abundance of H. pylori strains within a mixed population. We generated a library of hop mutant strains, each containing a unique nucleotide barcode, as well as a library of control strains, each containing a nucleotide barcode in an intergenic region predicted to be a neutral locus unrelated to bacterial fitness. We orogastrically inoculated each of the libraries into mice and analyzed compositional changes in the populations over time in vivo compared to changes detected in the populations during library passage in vitro . The control library proliferated as a relatively stable community in vitro, but there was a reduction in the population diversity of this library in vivo and marked variation in the dominant strains recovered from individual animals, consistent with the existence of a non-selective bottleneck in vivo . We did not identify any OMP mutants exhibiting fitness defects exclusively in vivo without corresponding fitness defects in vitro . Conversely, a babA mutant exhibited a strong fitness advantage in vivo but not in vitro . These findings, when taken together with results of other studies, suggest that production of BabA may have differential effects on H. pylori fitness depending on the environmental conditions.

scholarly journals Lactobacillus johnsonii La1 Attenuates Helicobacter pylori-Associated Gastritis and Reduces Levels of Proinflammatory Chemokines in C57BL/6 Mice

2005 ◽  
Vol 12 (12) ◽  
pp. 1378-1386 ◽  
Author(s):  
Dionyssios N. Sgouras ◽  
Effrosini G. Panayotopoulou ◽  
Beatriz Martinez-Gonzalez ◽  
Kalliopi Petraki ◽  
Spyros Michopoulos ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Lamina Propria ◽  
Serum Levels ◽  
Favorable Effect ◽  
Lactobacillus Johnsonii ◽  
Ags Cells ◽  
Inflammatory Infiltration ◽  
H Pylori

ABSTRACT In clinical settings, Lactobacillus johnsonii La1 administration has been reported to have a favorable effect on Helicobacter pylori-associated gastritis, although the mechanism remains unclear. We administered, continuously through the water supply, live La1 to H. pylori-infected C57BL/6 mice and followed colonization, the development of H. pylori-associated gastritis in the lamina propria, and the levels of proinflammatory chemokines macrophage inflammatory protein 2 (MIP-2) and keratinocyte-derived cytokine (KC) in the serum and gastric tissue over a period of 3 months. We documented a significant attenuation in both lymphocytic (P = 0.038) and neutrophilic (P = 0.003) inflammatory infiltration in the lamina propria as well as in the circulating levels of anti-H. pylori immunoglobulin G antibodies (P = 0.003), although we did not observe a suppressive effect of La1 on H. pylori colonizing numbers. Other lactobacilli, such as L. amylovorus DCE 471 and L. acidophilus IBB 801, did not attenuate H. pylori-associated gastritis to the same extent. MIP-2 serum levels were distinctly reduced during the early stages of H. pylori infection in the La1-treated animals, as were gastric mucosal levels of MIP-2 and KC. Finally, we also observed a significant reduction (P = 0.046) in H. pylori-induced interleukin-8 secretion by human adenocarcinoma AGS cells in vitro in the presence of neutralized (pH 6.8) La1 spent culture supernatants, without concomitant loss of H. pylori viability. These observations suggest that during the early infection stages, administration of La1 can attenuate H. pylori-induced gastritis in vivo, possibly by reducing proinflammatory chemotactic signals responsible for the recruitment of lymphocytes and neutrophils in the lamina propria.

scholarly journals Therapeutic effects of Zuojin Pill on Helicobacter pylori-induced chronic atrophic gastritis through JMJD2B/COX-2/VEGF signaling axis

2020 ◽  
Author(s):  
Shihua Wu ◽  
Chunmei Bao ◽  
Ruilin Wang ◽  
Xiaomei Zhang ◽  
Sijia Gao ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Cell Viability ◽  
Atrophic Gastritis ◽  
Chronic Atrophic Gastritis ◽  
Gastric Mucosal Damage ◽  
Therapeutic Effects ◽  
Cox 2 ◽  
H Pylori

Abstract Background: Zuojin Pill (ZJP), a famous Chinese medicinal formula, widely accepted for treatment of chronic atrophic gastritis (CAG) in China. This study aimed to explore the therapeutic effects and mechanisms of ZJP in Helicobacter pylori (H. pylori) - induced chronic atrophic gastritis (CAG) in vivo and in vitro. Methods: CAG rat model was induced by H. pylori. ZJP (0.63, 1.26, and 2.52 g/kg, respectively) was administered orally for four weeks. Therapeutic effects of ZJP were identified by H&E staining and serum indices. In addition, cell viability, morphology and proliferation were detected by cell counting kit-8 (CCK8) and high-content screening assay (HCS), respectively. Moreover, relative mRNA expression and protein expression related to JMJD2B/COX-2/VEGF axis was detected to investigate the potential mechanisms of ZJP in CAG. Results: Results showed the symptoms (weight loss and gastric mucosa damage) of CAG were alleviated, and the contents of TNF-α in serum was markedly decreased after treating with ZJP. Moreover, cell viability, proliferation and morphology changes of GES-1 cells were ameliorated by ZJP intervention. In addition, proinflammatory genes and JMJD2B/COX-2/VEGF axis related genes were suppressed by ZJP administration in vitro and in vivo. Meanwhile, immunohistochemistry (IHC) and western blot confirmed down-regulation of these genes by ZJP intervention. Conclusion: ZJP treatment can alleviate gastric mucosal damage induced by H. pylori via JMJD2B/COX-2/VEGF axis.

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