scholarly journals Role of Outer Membrane Vesicles From Helicobacter pylori in Atherosclerosis

2021 ◽  
Vol 9 ◽  
Author(s):  
Na Wang ◽  
Faying Zhou ◽  
Caiyu Chen ◽  
Hao Luo ◽  
Jingwen Guo ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Outer Membrane ◽  
Umbilical Vein ◽  
Membrane Vesicles ◽  
Plaque Formation ◽  
Outer Membrane Vesicles ◽  
Inflammatory Factors ◽  
Necrosis Factor Alpha ◽  
H Pylori

Infection is thought to be involved in the pathogenesis of atherosclerosis. Studies have shown the association between helicobacter pylori (H. pylori) and coronary artery disease. It is interesting to find H. pylori DNA and cytotoxin-associated gene A (CagA) protein in atherosclerotic plaque. Outer membrane vesicles (OMVs), secreted by H. pylori, exert effects in the distant organ or tissue. However, whether or not OMVs from H. pylori are involved in the pathogenesis of atherosclerosis remains unknown. Our present study found that treatment with OMVs from CagA-positive H. pylori accelerated atherosclerosis plaque formation in ApoE–/– mice. H. pylori-derived OMVs inhibited proliferation and promoted apoptosis of human umbilical vein endothelial cells (HUVECs), which was also reflected in in vivo studies. These effects were normalized to some degree after treatment with lipopolysaccharide (LPS)-depleted CagA-positive OMVs or CagA-negative OMVs. Treatment with H. pylori-derived OMVs increased reactive oxygen species (ROS) levels and enhanced the activation of nuclear factor-κB (NF-κB) in HUVECs, which were reversed to some degree in the presence of a superoxide dismutase mimetic TEMPOL and a NF-κB inhibitor BAY11-7082. Expressions of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α), two inflammatory factors, were augmented after treatment with OMVs from H. pylori. These suggest that H. pylori-derived OMVs accelerate atherosclerosis plaque formation via endothelium injury. CagA and LPS from H. pylori-OMVs, at least in part, participate in these processes, which may be involved with the activation of ROS/NF-κB signaling pathway. These may provide a novel strategy to reduce the incidence and development of atherosclerosis.

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

2021 ◽  
Vol 22 (9) ◽  
pp. 4823
Author(s):  
María Fernanda González ◽  
Paula Díaz ◽  
Alejandra Sandoval-Bórquez ◽  
Daniela Herrera ◽  
Andrew F. G. Quest
Keyword(s):  
Gastric Cancer ◽  
Helicobacter Pylori ◽  
Outer Membrane ◽  
Extracellular Vesicles ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Host Cells ◽  
Gastric Epithelium ◽  
Infected Cells ◽  
H Pylori

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.

scholarly journals Selective Inhibition of Helicobacter pylori Carbonic Anhydrases by Carvacrol and Thymol Could Impair Biofilm Production and the Release of Outer Membrane Vesicles

2021 ◽  
Vol 22 (21) ◽  
pp. 11583
Author(s):  
Rossella Grande ◽  
Simone Carradori ◽  
Valentina Puca ◽  
Irene Vitale ◽  
Andrea Angeli ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Outer Membrane ◽  
Bacterial Resistance ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Peptic Ulcers ◽  
Carbonic Anhydrases ◽  
Biofilm Production ◽  
Isoform Selectivity ◽  
H Pylori

Helicobacter pylori, a Gram-negative neutrophilic pathogen, is the cause of chronic gastritis, peptic ulcers, and gastric cancer in humans. Current therapeutic regimens suffer from an emerging bacterial resistance rate and poor patience compliance. To improve the discovery of compounds targeting bacterial alternative enzymes or essential pathways such as carbonic anhydrases (CAs), we assessed the anti-H. pylori activity of thymol and carvacrol in terms of CA inhibition, isoform selectivity, growth impairment, biofilm production, and release of associated outer membrane vesicles-eDNA. The microbiological results were correlated by the evaluation in vitro of H. pylori CA inhibition, in silico analysis of the structural requirements to display such isoform selectivity, and the assessment of their limited toxicity against three probiotic species with respect to amoxicillin. Carvacrol and thymol could thus be considered as new lead compounds as alternative H. pylori CA inhibitors or to be used in association with current drugs for the management of H. pylori infection and limiting the spread of antibiotic resistance.

scholarly journals Helicobacter pylori-Derived Outer Membrane Vesicles (OMVs): Role in Bacterial Pathogenesis?

2020 ◽  
Vol 8 (9) ◽  
pp. 1328 ◽  
Author(s):  
Miroslaw Jarzab ◽  
Gernot Posselt ◽  
Nicole Meisner-Kober ◽  
Silja Wessler
Keyword(s):  
Helicobacter Pylori ◽  
Outer Membrane ◽  
Current Knowledge ◽  
Membrane Vesicles ◽  
Bacterial Pathogenesis ◽  
Outer Membrane Vesicles ◽  
Host Cells ◽  
Cellular Mechanisms ◽  
Wide Range ◽  
H Pylori

Persistent infections with the human pathogen Helicobacter pylori (H. pylori) have been closely associated with the induction and progression of a wide range of gastric disorders, including acute and chronic gastritis, ulceration in the stomach and duodenum, mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric adenocarcinoma. The pathogenesis of H. pylori is determined by a complicated network of manifold mechanisms of pathogen–host interactions, which involves a coordinated interplay of H. pylori pathogenicity and virulence factors with host cells. While these molecular and cellular mechanisms have been intensively investigated to date, the knowledge about outer membrane vesicles (OMVs) derived from H. pylori and their implication in bacterial pathogenesis is not well developed. In this review, we summarize the current knowledge on H. pylori-derived OMVs.

scholarly journals Crude Preparations of Helicobacter pylori Outer Membrane Vesicles Induce Upregulation of Heme Oxygenase-1 via Activating Akt-Nrf2 and mTOR–IκB Kinase–NF-κB Pathways in Dendritic Cells

2016 ◽  
Vol 84 (8) ◽  
pp. 2162-2174 ◽  
Author(s):  
Su Hyuk Ko ◽  
Da Jeong Rho ◽  
Jong Ik Jeon ◽  
Young-Jeon Kim ◽  
Hyun Ae Woo ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Dendritic Cells ◽  
Outer Membrane ◽  
Heme Oxygenase ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Heme Oxygenase 1 ◽  
Content Type ◽  
Iκb Kinase ◽  
H Pylori

Helicobacter pylorisheds outer membrane vesicles (OMVs) that contain many surface elements of bacteria. Dendritic cells (DCs) play a major role in directing the nature of adaptive immune responses againstH. pylori, and heme oxygenase-1 (HO-1) has been implicated in regulating function of DCs. In addition, HO-1 is important for adaptive immunity and the stress response. AlthoughH. pylori-derived OMVs may contribute to the pathogenesis ofH. pyloriinfection, responses of DCs to OMVs have not been elucidated. In the present study, we investigated the role ofH. pylori-derived crude OMVs in modulating the expression of HO-1 in DCs. Exposure of DCs to crudeH. pyloriOMVs upregulated HO-1 expression. Crude OMVs obtained from acagA-negative isogenic mutant strain induced less HO-1 expression than OMVs obtained from a wild-type strain. CrudeH. pyloriOMVs activated signals of transcription factors such as NF-κB, AP-1, and Nrf2. Suppression of NF-κB or Nrf2 resulted in significant attenuation of crude OMV-induced HO-1 expression. Crude OMVs increased the phosphorylation of Akt and downstream target molecules of mammalian target of rapamycin (mTOR), such as S6 kinase 1 (S6K1). Suppression of Akt resulted in inhibition of crude OMV-induced Nrf2-dependent HO-1 expression. Furthermore, suppression of mTOR was associated with inhibition of IκB kinase (IKK), NF-κB, and HO-1 expression in crude OMV-exposed DCs. These results suggest thatH. pylori-derived OMVs regulate HO-1 expression through two different pathways in DCs, Akt-Nrf2 and mTOR–IKK–NF-κB signaling. Following this induction, increased HO-1 expression in DCs may modulate inflammatory responses inH. pyloriinfection.

scholarly journals Helicobacter pylori Outer Membrane Vesicles Modulate Proliferation and Interleukin-8 Production by Gastric Epithelial Cells

2003 ◽  
Vol 71 (10) ◽  
pp. 5670-5675 ◽  
Author(s):  
Salim Ismail ◽  
Mark B. Hampton ◽  
Jacqueline I. Keenan
Keyword(s):  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Outer Membrane ◽  
Strain Differences ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Interleukin 8 ◽  
Low Grade ◽  
Gastric Epithelial Cells ◽  
H Pylori

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.

scholarly journals Uptake of Helicobacter pylori Outer Membrane Vesicles by Gastric Epithelial Cells

2010 ◽  
Vol 78 (12) ◽  
pp. 5054-5061 ◽  
Author(s):  
Heather Parker ◽  
Kenny Chitcholtan ◽  
Mark B. Hampton ◽  
Jacqueline I. Keenan
Keyword(s):  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Outer Membrane ◽  
Mutant Strain ◽  
Membrane Vesicles ◽  
Human Stomach ◽  
Outer Membrane Vesicles ◽  
Gastric Epithelial Cells ◽  
Isogenic Mutant Strain ◽  
H Pylori

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.

scholarly journals Orally-administered outer-membrane vesicles from Helicobacter pylori reduce H. pylori infection via Th2-biased immune responses in mice

2019 ◽  
Vol 77 (5) ◽  
Author(s):  
Qiong Liu ◽  
Xiuzhen Li ◽  
Yingxuan Zhang ◽  
Zifan Song ◽  
Ruizhen Li ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Immune Responses ◽  
Outer Membrane ◽  
Protein Composition ◽  
Membrane Vesicles ◽  
Oral Immunization ◽  
Outer Membrane Vesicles ◽  
Extracellular Proteins ◽  
Cell Vaccine ◽  
H Pylori

ABSTRACT As the trend of antibiotic resistance has increased, prevention and treatment of Helicobacter pylori infection have been challenged by the fact that no vaccines preventing H. pylori infection are available. Scientists continue to make sustained efforts to find better vaccine formulations and adjuvants to eradicate this chronic infection. In this study, we systemically analyzed the protein composition and potential vaccine function of outer-membrane vesicles (OMVs) derived from gerbil-adapted H. pylori strain 7.13. In total, we identified 169 proteins in H. pylori OMVs and found that outer-membrane, periplasmic and extracellular proteins (48.9% of the total proteins) were enriched. Furthermore, we evaluated the immune protective response of H. pylori OMVs in a C57BL/6 mouse model, and mice were orally immunized with OMVs or the H. pylori whole cell vaccine (WCV) alone, with or without cholera toxin (CT) as an adjuvant. The data demonstrated that oral immunization with OMVs can elicit a strong humoral and significantly higher mucosal immune response than the group immunized with the WCV plus the CT adjuvant. Moreover, our results also confirmed that OMVs predominantly induced T helper 2 (Th2)-biased immune responses that can significantly reduce bacterial loads after challenging with the H. pylori Sydney Strain 1 (SS1). In summary, OMVs as new antigen candidates in vaccine design would be of great value in controlling H. pylori infection.

scholarly journals Role of Activated Protein C in Helicobacter pylori-Associated Gastritis

2000 ◽  
Vol 68 (5) ◽  
pp. 2863-2869 ◽  
Author(s):  
Satoko Oka ◽  
Esteban Cesar Gabazza ◽  
Yukiko Taguchi ◽  
Michihiko Yamaguchi ◽  
Shigehito Nakashima ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Protein C ◽  
Activated Protein C ◽  
Mucosal Damage ◽  
Gastric Mucosal Damage ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Gastric Corpus ◽  
H Pylori

ABSTRACT The protein C (PC) pathway has recently been suggested to play a role in the regulation of the inflammatory response. To further extend the anti-inflammatory effect of activated PC (APC) in vivo, particularly its biological relevance to human disease, the activity of APC in the mucosa of patients with Helicobacter pylori-associated gastritis and the effect of vacuolating cytotoxin (VacA), cytotoxin-associated antigen (CagA), andH. pylori lipopolysaccharide (LPS) on PC activation were evaluated. This study comprised 35 patients with chronic gastritis. There were 20 patients with and 15 without H. pylori infection. The levels of PC and APC-PC inhibitor (PCI) complex were measured by immunoassays. The level of PC was significantly decreased and the level of APC-PCI complex was significantly increased in biopsy specimens from gastric corpus and antrum in patients with H. pylori-associated gastritis as compared to H. pylori-negative subjects. The concentrations of VacA, CagA, and LPS were significantly correlated with those of the APC-PCI complex in biopsy mucosal specimens from the gastric corpus and antrum. H. pylori LPS, VacA, and CagA induced a dose-dependent activation of PC on the surface of monocytic cells. APC inhibited the secretion of tumor necrosis factor alpha (TNF-α) induced by H. pylori LPS. Overall, these results suggest that H. pylori infection is associated with increased APC generation in the gastric mucosa. The inhibitory activity of APC on TNF-α secretion may serve to protect H. pylori-induced gastric mucosal damage.

scholarly journals Carbonic Anhydrases: New Perspectives on Protein Functional Role and Inhibition in Helicobacter pylori

2021 ◽  
Vol 12 ◽  
Author(s):  
Cristina Campestre ◽  
Viviana De Luca ◽  
Simone Carradori ◽  
Rossella Grande ◽  
Vincenzo Carginale ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Pathogenic Bacteria ◽  
Acid Tolerance ◽  
Membrane Vesicles ◽  
Research Field ◽  
Outer Membrane Vesicles ◽  
Bacterial Toxin ◽  
Carbonic Anhydrases ◽  
Ph Homeostasis ◽  
H Pylori

Our understanding of the function of bacterial carbonic anhydrases (CAs, EC 4.2.1.1) has increased significantly in the last years. CAs are metalloenzymes able to modulate CO2, HCO3– and H+ concentration through their crucial role in catalysis of reversible CO2 hydration (CO2 + H2O ⇄ HCO3– + H+). In all living organisms, CA activity is linked to physiological processes, such as those related to the transport and supply of CO2 or HCO3–, pH homeostasis, secretion of electrolytes, biosynthetic processes and photosynthesis. These important processes cannot be ensured by the very low rate of the non-catalyzed reaction of CO2 hydration. It has been recently shown that CAs are important biomolecules for many bacteria involved in human infections, such as Vibrio cholerae, Brucella suis, Salmonella enterica, Pseudomonas aeruginosa, and Helicobacter pylori. In these species, CA activity promotes microorganism growth and adaptation in the host, or modulates bacterial toxin production and virulence. In this review, recent literature in this research field and some of the above-mentioned issues are discussed, namely: (i) the implication of CAs from bacterial pathogens in determining the microorganism growth and virulence; (ii) the druggability of these enzymes using classical CA inhibitors (CAIs) of the sulfonamide-type as examples; (iii) the role played by Helicobacter pylori CAs in the acid tolerance/adaptation of the microbe within the human abdomen; (iv) the role of CAs played in the outer membrane vesicles spawned by H. pylori in its planktonic and biofilm phenotypes; (v) the possibility of using H. pylori CAIs in combination with probiotic strains as a novel anti-ulcer treatment approach. The latter approach may represent an innovative and successful strategy to fight gastric infections in the era of increasing resistance of pathogenic bacteria to classical antibiotics.

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