The Effect of Helicobacter Pylori Outer Membrane Vesicles On Vacuolation in Gastric and Colonic Epithelial Cells

Endoscopy ◽  
2006 ◽  
Vol 38 (11) ◽  
Author(s):  
EM Mullaney ◽  
AM Terres ◽  
DP Kelleher
2003 ◽  
Vol 71 (10) ◽  
pp. 5670-5675 ◽  
Author(s):  
Salim Ismail ◽  
Mark B. Hampton ◽  
Jacqueline I. Keenan

ABSTRACT Helicobacter pylori infection, which is always associated with gastritis, can progress to ulceration or malignancy. The diversity in clinical outcomes is partly attributed to the expression of virulence factors and adhesins by H. pylori. However, H. pylori may not have to adhere to the epithelium to cause gastritis. We hypothesize that outer membrane vesicles (OMV), which are constantly shed from the surface of H. pylori, play a role as independent activators of host cell responses. In this study, we found that low doses of OMV from cag PAI+ toxigenic and cag PAI− nontoxigenic strains increased proliferation of AGS gastric epithelial cells. At higher doses, we detected growth arrest, increased toxicity, and interleukin-8 (IL-8) production. The only strain differences detected were vacuolation with the toxigenic strain and higher levels of IL-8 production with OMV from the cag PAI− nontoxigenic strain. In summary, we suggest that constitutively shed OMV play a role in promoting the low-grade gastritis associated with H. pylori infection.


2010 ◽  
Vol 78 (12) ◽  
pp. 5054-5061 ◽  
Author(s):  
Heather Parker ◽  
Kenny Chitcholtan ◽  
Mark B. Hampton ◽  
Jacqueline I. Keenan

ABSTRACT Helicobacter pylori bacteria colonize the human stomach where they stimulate a persistent inflammatory response. H. pylori is considered noninvasive; however, lipopolysaccharide (LPS)-enriched outer membrane vesicles (OMV), continuously shed from the surface of this bacterium, are observed within gastric epithelial cells. The mechanism of vesicle uptake is poorly understood, and this study was undertaken to examine the roles of bacterial VacA cytotoxin and LPS in OMV binding and cholesterol and clathrin-mediated endocytosis in vesicle uptake by gastric epithelial cells. OMV association was examined using a fluorescent membrane dye to label OMV, and a comparison was made between the associations of vesicles from a VacA+ strain and OMV from a VacA− isogenic mutant strain. Within 20 min, essentially all associated OMV were intracellular, and vesicle binding appeared to be facilitated by the presence of VacA cytotoxin. Uptake of vesicles from the VacA+ strain was inhibited by H. pylori LPS (58% inhibition with 50 μg/ml LPS), while uptake of OMV from the VacA− mutant strain was less affected (25% inhibition with 50 μg/ml LPS). Vesicle uptake did not require cholesterol. However, uptake of OMV from the VacA− mutant strain was inhibited by a reduction in clathrin-mediated endocytosis (42% with 15 μg/ml chlorpromazine), while uptake of OMV from the VacA+ strain was less affected (25% inhibition with 15 μg/ml chlorpromazine). We conclude that VacA toxin enhances the association of H. pylori OMV with cells and that the presence of the toxin may allow vesicles to exploit more than one pathway of internalization.


2021 ◽  
Vol 22 (9) ◽  
pp. 4823
Author(s):  
María Fernanda González ◽  
Paula Díaz ◽  
Alejandra Sandoval-Bórquez ◽  
Daniela Herrera ◽  
Andrew F. G. Quest

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.


2019 ◽  
Vol 316 (1) ◽  
pp. L206-L215 ◽  
Author(s):  
Roxanna Barnaby ◽  
Katja Koeppen ◽  
Bruce A. Stanton

Pseudomonas aeruginosa secretes outer-membrane vesicles (OMVs) that fuse with cholesterol-rich lipid rafts in the apical membrane of airway epithelial cells and decrease wt-CFTR Cl− secretion. Herein, we tested the hypothesis that a reduction of the cholesterol content of CF human airway epithelial cells by cyclodextrins reduces the inhibitory effect of OMVs on VX-809 (lumacaftor)-stimulated Phe508del CFTR Cl− secretion. Primary CF bronchial epithelial cells and CFBE cells were treated with vehicle, hydroxypropyl-β-cyclodextrin (HPβCD), or methyl-β-cyclodextrin (MβCD), and the effects of OMVs secreted by P. aeruginosa on VX-809 stimulated Phe508del CFTR Cl− secretion were measured in Ussing chambers. Neither HPβCD nor MβCD were cytotoxic, and neither altered Phe508del CFTR Cl− secretion. Both cyclodextrins reduced OMV inhibition of VX-809-stimulated Phe508del-CFTR Cl− secretion when added to the apical side of CF monolayers. Both cyclodextrins also reduced the ability of P. aeruginosa to form biofilms and suppressed planktonic growth of P. aeruginosa. Our data suggest that HPβCD, which is in clinical trials for Niemann-Pick Type C disease, and MβCD, which has been approved by the U.S. Food and Drug Administration for use in solubilizing lipophilic drugs, may enhance the clinical efficacy of VX-809 in CF patients when added to the apical side of airway epithelial cells, and reduce planktonic growth and biofilm formation by P. aeruginosa. Both effects would be beneficial to CF patients.


Helicobacter ◽  
2005 ◽  
Vol 10 (2) ◽  
pp. 146-156 ◽  
Author(s):  
Sean O. Hynes ◽  
Jacqueline I. Keenan ◽  
John A. Ferris ◽  
Heidi Annuk ◽  
Anthony P. Moran

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