scholarly journals Specific Entry of Helicobacter pylori into Cultured Gastric Epithelial Cells via a Zipper-Like Mechanism

2002 ◽  
Vol 70 (4) ◽  
pp. 2108-2120 ◽  
Author(s):  
Terry Kwok ◽  
Steffen Backert ◽  
Heinz Schwarz ◽  
Jürgen Berger ◽  
Thomas F. Meyer
Keyword(s):  
Helicobacter Pylori ◽  
Cell Model ◽  
Close Association ◽  
Host Cells ◽  
Mammalian Host ◽  
Dependent Manner ◽  
Filamentous Actin ◽  
Ags Cells ◽  
Necrosis Factor Alpha ◽  
H Pylori

ABSTRACT Although Helicobacter pylori has generally been considered an extracellular pathogen, a number of in vitro infection experiments and biopsy examinations have shown that it is capable of occasionally entering mammalian host cells. Here, we characterized this entry process by using AGS cells as a host cell model. In gentamicin protection-invasion assays, the number of H. pylori colonies recovered was lower than that for Salmonella enterica serovar Typhimurium X22, Escherichia coli expressing InvA, and Yersinia enterocolitica YO:9 grown at 25°C but higher than that for Neisseria gonorrhoeae VP1 and Y. enterocolitica YO:9 grown at 37°C. At the ultrastructural level, the entry process was observed to occur via a zipper-like mechanism. Internalized H. pylori was bound in tight LAMP-1-containing vacuoles in close association with condensed filamentous actin and tyrosine phosphorylation signals. Wortmannin, a potent inhibitor of phosphatidylinositol 3-kinase, and calphostin C, an inhibitor of protein kinase C, both inhibited the entry of H. pylori in a sensitive and dose-dependent manner; however, the level of entry was enhanced by sodium vanadate, an inhibitor of tyrosine phosphatases and ATPases. Furthermore, the cytokine tumor necrosis factor alpha antagonized the entry of H. pylori into AGS cells. Collectively, these results demonstrate that the entry of H. pylori into AGS cells occurs via a zipper-like mechanism which involves various host signal transduction events.

scholarly journals Targeted mobilization of Lrig1+ gastric epithelial stem cell populations by a carcinogenic Helicobacter pylori type IV secretion system

2019 ◽  
Vol 116 (39) ◽  
pp. 19652-19658 ◽  
Author(s):  
Lydia E. Wroblewski ◽  
Eunyoung Choi ◽  
Christine Petersen ◽  
Alberto G. Delgado ◽  
M. Blanca Piazuelo ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Stem Cell ◽  
Progenitor Cells ◽  
Intrinsic Factor ◽  
Secretion System ◽  
Lineage Tracing ◽  
Host Cells ◽  
Dependent Manner ◽  
Cell Marker ◽  
H Pylori

Helicobacter pylori-induced gastritis is the strongest risk factor for gastric adenocarcinoma, a malignancy preceded by a series of well-defined histological stages, including metaplasia. One microbial constituent that augments cancer risk is the cag type 4 secretion system (T4SS), which translocates the oncoprotein CagA into host cells. Aberrant stem cell activation is linked to carcinogenesis, and Lrig1 (leucine-rich repeats and Ig-like domains 1) marks a distinct population of progenitor cells. We investigated whether microbial effectors with carcinogenic potential influence Lrig1 progenitor cells ex vivo and via lineage expansion within H. pylori-infected gastric mucosa. Lineage tracing was induced in Lrig1-CreERT2/+;R26R-YFP/+ (Lrig1/YFP) mice that were uninfected or subsequently infected with cag+H. pylori or an isogenic cagE− mutant (nonfunctional T4SS). In contrast to infection with wild-type (WT) H. pylori for 2 wk, infection for 8 wk resulted in significantly increased inflammation and proliferation in the corpus and antrum compared with uninfected or mice infected with the cagE− mutant. WT H. pylori-infected mice harbored significantly higher numbers of Lrig1/YFP epithelial cells that coexpressed UEA1 (surface cell marker). The number of cells coexpressing intrinsic factor (chief cell marker), YFP (lineage marker), and GSII lectin (spasmolytic polypeptide-expressing metaplasia marker) were increased only by WT H. pylori. In human samples, Lrig1 expression was significantly increased in lesions with premalignant potential compared with normal mucosa or nonatrophic gastritis. In conclusion, chronic H. pylori infection stimulates Lrig1-expressing progenitor cells in a cag-dependent manner, and these reprogrammed cells give rise to a full spectrum of differentiated cells.

scholarly journals SHP2-independent tyrosine dephosphorylation of cortactin and vinculin during infection with Helicobacter pylori

2020 ◽  
Vol 10 (1) ◽  
pp. 20-27
Author(s):  
Jakob Knorr ◽  
Steffen Backert ◽  
Nicole Tegtmeyer
Keyword(s):  
Helicobacter Pylori ◽  
Host Cell ◽  
Tyrosine Phosphatase ◽  
Actin Binding ◽  
World Population ◽  
Dependent Manner ◽  
Knockout Mutant ◽  
Ags Cells ◽  
Type Iv ◽  
H Pylori

The gastric pathogen Helicobacter pylori colonizes approximately half of the human world population. The bacterium injects the effector protein cytotoxin associated gene A (CagA) via a type-IV secretion system into host epithelial cells, where the protein becomes phosphorylated at specific EPIYA-motifs by cellular kinases. Inside the host cell, CagA can interact with over 25 different proteins in both phosphorylation-dependent and phosphorylation-independent manners, resulting in manipulation of host-cell signaling pathways. During the course of an H. pylori infection, certain host-cell proteins undergo tyrosine dephosphorylation in a CagA-dependent manner, including the actin-binding proteins cortactin and vinculin. A predominant response of intracellular CagA is the binding and activation of tyrosine phosphatase, the human Src-homology-region-2-domain-containing-phosphatase-2 (SHP2). Here, we considered the possibility that activated SHP2 might be responsible for the dephosphorylation of cortactin and vinculin. To investigate this, phosphatase inhibitor studies were performed. Additionally, a complete knockout mutant of SHP2 in AGS cells was created by CRISPR/Cas9 technology, and these cells were infected with H. pylori. However, neither the presence of an inhibitor nor the inactivation of SHP2 prevented the dephosphorylation of cortactin and vinculin upon CagA delivery. Tyrosine dephosphorylation of these proteins is therefore independent of SHP2 and instead must be caused by another, as yet unidentified, protein tyrosine phosphatase.

scholarly journals Inhibitors of Helicobacter pylori ATPase Cagα block CagA transport and cag virulence

Microbiology ◽  
2006 ◽  
Vol 152 (10) ◽  
pp. 2919-2930 ◽  
Author(s):  
Markus Hilleringmann ◽  
Werner Pansegrau ◽  
Michael Doyle ◽  
Susan Kaufman ◽  
Mary Lee MacKichan ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Small Molecule ◽  
High Throughput Screening ◽  
Host Cells ◽  
Dependent Manner ◽  
Secretion Systems ◽  
Ags Cells ◽  
Antibacterial Compounds ◽  
Cellular Effects

With the steadily increasing occurrence of antibiotic resistance in bacteria, there is a great need for new antibacterial compounds. The approach described here involves targeting virulence-related bacterial type IV secretion systems (TFSSs) with small-molecule inhibitors. The cag TFSS of Helicobacter pylori was chosen as a model, and novel inhibitors directed against the cag VirB11-type ATPase Cagα were identified. The cag genes encode proteins that are components of a contact-dependent secretion system used by the bacterium to translocate the effector molecule CagA into host cells. Translocated CagA is associated with severe gastritis, and carcinoma. Furthermore, functional TFSSs and immunodominant CagA play a role in interleukin (IL)-8 induction, which is an important factor for chronic inflammation. Inhibitors of Cagα were identified by high-throughput screening of chemical libraries that comprised 524 400 small molecules. The ATPase activity of Cagα was inhibited by the selected compounds in an in vitro enzymic assay using the purified enzyme. The most active compound, CHIR-1, reduced TFSS function to an extent that cellular effects on AGS cells mediated by CagA were virtually undetectable, while reduced levels of IL-8 induction were observed. Gastric colonization by CHIR-1-pre-treated bacteria was found to be impaired in a dose-dependent manner using a mouse model of infection. Small-molecule Cagα inhibitors, the first described inhibitors of a TFSS, are potential candidates for the development of new antibacterial compounds that may lead to alternative medical treatments. The compounds are expected to impose weak selective pressure, since they target virulence functions. Moreover, the targeted virulence protein is conserved in a variety of bacterial pathogens. Additionally, TFSS inhibitors are potent tools to study the biology of TFSSs.

scholarly journals Evodiamine Inhibits Helicobacter pylori Growth and Helicobacter pylori-Induced Inflammation

2021 ◽  
Vol 22 (7) ◽  
pp. 3385
Author(s):  
Ji Yeong Yang ◽  
Jong-Bae Kim ◽  
Pyeongjae Lee ◽  
Sa-Hyun Kim
Keyword(s):  
Gastric Cancer ◽  
Helicobacter Pylori ◽  
Secretion System ◽  
Host Cells ◽  
World Health ◽  
Ags Cells ◽  
Inhibitory Mechanisms ◽  
Anti Inflammatory ◽  
H Pylori ◽  
Bacterial Effect

Helicobacter pylori (H. pylori) classified as a class I carcinogen by the World Health Organization (WHO) plays an important role in the progression of chronic gastritis and the development of gastric cancer. A major bioactive component of Evodia rutaecarpa, evodiamine, has been known for its anti-bacterial effect and anti-cancer effects. However, the inhibitory effect of evodiamine against H. pylori is not yet known and the inhibitory mechanisms of evodiamine against gastric cancer cells are yet to be elucidated concretely. In this study, therefore, anti-bacterial effect of evodiamine on H. pylori growth and its inhibitory mechanisms as well as anti-inflammatory effects and its mechanisms of evodiamine on H. pylori-induced inflammation were investigated in vitr. Results of this study showed the growth of the H. pylori reference strains and clinical isolates were inhibited by evodiamine. It was considered one of the inhibitory mechanisms that evodiamine downregulated both gene expressions of replication and transcription machineries of H. pylori. Treatment of evodiamine also induced downregulation of urease and diminished translocation of cytotoxin-associated antigen A (CagA) and vacuolating cytotoxin A (VacA) proteins into gastric adenocarcinoma (AGS) cells. This may be resulted from the reduction of CagA and VacA expressions as well as the type IV secretion system (T4SS) components and secretion system subunit protein A (SecA) protein which are involved in translocation of CagA and VacA into host cells, respectively. In particular, evodiamine inhibited the activation of signaling proteins such as the nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) and the mitogen-activated protein kinase (MAPK) pathway induced by H. pylori infection. It consequently might contribute to reduction of interleukin (IL)-8 production in AGS cells. Collectively, these results suggest anti-bacterial and anti-inflammatory effects of evodiamine against H. pylori.

scholarly journals Helicobacter pylori Activates the Early Growth Response 1 Protein in Gastric Epithelial Cells

2004 ◽  
Vol 72 (6) ◽  
pp. 3549-3560 ◽  
Author(s):  
M. M. M. Abdel-Latif ◽  
H. J. Windle ◽  
K. A. Fitzgerald ◽  
Y. S. Ang ◽  
D. Ní Eidhin ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Growth Response ◽  
Early Growth ◽  
Dependent Manner ◽  
Mobility Shift ◽  
Ags Cells ◽  
Early Growth Response ◽  
H Pylori ◽  
Early Growth Response 1

ABSTRACT The early growth response 1 (Egr-1) transcription factor is rapidly induced by various stimuli and is implicated in the regulation of cell growth, differentiation, and gene expression. The aim of this study was to examine the effect of Helicobacter pylori on the expression of Egr-1 and Egr-1-regulated genes in gastric epithelial AGS cells. Egr-1 expression was assayed by immunoblotting and electrophoretic mobility shift assays using H. pylori-stimulated AGS cells. Transient transfection experiments with promoter-reporter constructs of CD44, ICAM-1, and CD95L were used for expression studies. H. pylori induced the expression of Egr-1 in gastric epithelial cell lines in a dose-dependent manner, with the rapid kinetics that are typical of this class of transcription factors. Immunohistochemical studies of biopsies revealed that Egr-1 expression is more abundant in H. pylori-positive patients than in uninfected individuals. Reporter-promoter transfection studies indicated that Egr-1 binding is required for the H. pylori-induced transcriptional promoter activity of the CD44, ICAM-1, and CD95L (APO-1/Fas) constructs. The blocking of egr-1 with an antisense sequence prevented H. pylori-induced Egr-1 and CD44 protein expression. The MEK1/2 signaling cascade participates in H. pylori-mediated Egr-1 expression, but the p38 pathway does not. The data indicate that H. pylori induces Egr-1 expression in AGS cells in vitro and that the Egr-1 protein is readily detectable in biopsies from H. pylori-positive subjects. These observations suggest that H. pylori-associated Egr-1 expression may play a role, in part, in H. pylori-induced pathology.

scholarly journals Inhibitory Effects of Menadione on Helicobacter pylori Growth and Helicobacter pylori-Induced Inflammation via NF-κB Inhibition

2019 ◽  
Vol 20 (5) ◽  
pp. 1169 ◽  
Author(s):  
Min Lee ◽  
Ji Yang ◽  
Yoonjung Cho ◽  
Hyun Woo ◽  
Hye Kwon ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Protein A ◽  
Leukemia Cell ◽  
Host Cells ◽  
Monocytic Leukemia ◽  
Ags Cells ◽  
Type Iv ◽  
Group I ◽  
Anti Inflammatory ◽  
H Pylori

H. pylori is classified as a group I carcinogen by WHO because of its involvement in gastric cancer development. Several reports have suggested anti-bacterial effects of menadione, although the effect of menadione on major virulence factors of H. pylori and H. pylori-induced inflammation is yet to be elucidated. In this study, therefore, we demonstrated that menadione has anti-H. pylori and anti-inflammatory effects. Menadione inhibited growth of H. pylori reference strains and clinical isolates. Menadione reduced expression of vacA in H. pylori, and translocation of VacA protein into AGS (gastric adenocarcinoma cell) was also decreased by menadione treatment. This result was concordant with decreased apoptosis in AGS cells infected with H. pylori. Moreover, cytotoxin-associated protein A (CagA) translocation into H. pylori-infected AGS cells was also decreased by menadione. Menadione inhibited expression of several type IV secretion system (T4SS) components, including virB2, virB7, virB8, and virB10, that are responsible for translocation of CagA into host cells. In particular, menadione inhibited nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) activation and thereby reduced expression of the proinflammatory cytokines such as IL-1β, IL-6, IL-8, and TNF-α in AGS as well as in THP-1 (monocytic leukemia cell) cell lines. Collectively, these results suggest the anti-bacterial and anti-inflammatory effects of menadione against H. pylori.

scholarly journals TLR9 activation suppresses inflammation in response to Helicobacter pylori infection

2016 ◽  
Vol 311 (5) ◽  
pp. G852-G858 ◽  
Author(s):  
Matthew G. Varga ◽  
M. Blanca Piazuelo ◽  
Judith Romero-Gallo ◽  
Alberto G. Delgado ◽  
Giovanni Suarez ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Disease Risk ◽  
Host Cells ◽  
Dependent Manner ◽  
Wild Type ◽  
Host Genotype ◽  
Immunological Responses ◽  
Type Iv ◽  
H Pylori

Helicobacter pylori ( H. pylori) induces chronic gastritis in humans, and infection can persist for decades. One H. pylori strain-specific constituent that augments disease risk is the cag pathogenicity island. The cag island encodes a type IV secretion system (T4SS) that translocates DNA into host cells. Toll-like receptor 9 (TLR9) is an innate immune receptor that detects hypo-methylated CpG DNA motifs. In this study, we sought to define the role of the H. pylori cag T4SS on TLR9-mediated responses in vivo. H. pylori strain PMSS1 or its cagE − mutant, which fails to assemble a T4SS, were used to infect wild-type or Tlr9 −/− C57BL/6 mice. PMSS1-infected Tlr9 −/− mice developed significantly higher levels of inflammation, despite similar levels of colonization density, compared with PMSS1-infected wild-type mice. These changes were cag dependent, as both mouse genotypes infected with the cagE − mutant only developed minimal inflammation. Tlr9 −/− genotypes did not alter the microbial phenotypes of in vivo-adapted H. pylori strains; therefore, we examined host immunological responses. There were no differences in levels of TH1 or TH2 cytokines in infected mice when stratified by host genotype. However, gastric mucosal levels of IL-17 were significantly increased in infected Tlr9 −/− mice compared with infected wild-type mice, and H. pylori infection of IL-17A −/− mice concordantly led to significantly decreased levels of gastritis. Thus loss of Tlr9 selectively augments the intensity of IL-17-driven immune responses to H. pylori in a cag T4SS-dependent manner. These results suggest that H. pylori utilizes the cag T4SS to manipulate the intensity of the host immune response.

scholarly journals Outer Membrane Vesicle Production by Helicobacter pylori Represents an Approach for the Delivery of Virulence Factors CagA, VacA and UreA into Human Gastric Adenocarcinoma (AGS) Cells

2021 ◽  
Vol 22 (8) ◽  
pp. 3942
Author(s):  
Yongyu Chew ◽  
Hsin-Yu Chung ◽  
Po-Yi Lin ◽  
Deng-Chyang Wu ◽  
Shau-Ku Huang ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Outer Membrane ◽  
Gastric Adenocarcinoma ◽  
Virulence Factors ◽  
Outer Membrane Vesicles ◽  
Host Cells ◽  
Ags Cells ◽  
Α Subunit ◽  
Human Gastric Adenocarcinoma ◽  
H Pylori

Helicobacter pylori infection is the etiology of several gastric-related diseases including gastric cancer. Cytotoxin associated gene A (CagA), vacuolating cytotoxin A (VacA) and α-subunit of urease (UreA) are three major virulence factors of H. pylori, and each of them has a distinct entry pathway and pathogenic mechanism during bacterial infection. H. pylori can shed outer membrane vesicles (OMVs). Therefore, it would be interesting to explore the production kinetics of H. pylori OMVs and its connection with the entry of key virulence factors into host cells. Here, we isolated OMVs from H. pylori 26,695 strain and characterized their properties and interaction kinetics with human gastric adenocarcinoma (AGS) cells. We found that the generation of OMVs and the presence of CagA, VacA and UreA in OMVs were a lasting event throughout different phases of bacterial growth. H. pylori OMVs entered AGS cells mainly through macropinocytosis/phagocytosis. Furthermore, CagA, VacA and UreA could enter AGS cells via OMVs and the treatment with H. pylori OMVs would cause cell death. Comparison of H. pylori 26,695 and clinical strains suggested that the production and characteristics of OMVs are not only limited to laboratory strains commonly in use, but a general phenomenon to most H. pylori strains.

scholarly journals Fucoidan from Sargassum hemiphyllum inhibits infection and inflammation of Helicobacter pylori

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Bo-Rui Chen ◽  
Wei-Ming Li ◽  
Tsung-Lin Li ◽  
Yi-Lin Chan ◽  
Chang-Jer Wu
Keyword(s):  
Drug Resistance ◽  
Helicobacter Pylori ◽  
Cell Model ◽  
Host Cells ◽  
Total Count ◽  
Gastric Adenoma ◽  
Antibiotic Failure ◽  
H Pylori ◽  
Sargassum Hemiphyllum

AbstractHaving infected by Helicobacter pylori, the infection often leads to gastritis, gastric ulcer, or even gastric cancer. The disease is typically treated with antibiotics as they used to effectively inhibit or kill H. pylori, thus reducing the incidence of gastric adenoma and cancer to significant extent. H. pylori, however, has developed drug resistance to many clinically used antibiotics over the years, highlighting the crisis of antibiotic failure during the H. pylori treatment. We report here that the fucoidan from Sargassum hemiphyllum can significantly reduce the infection of H. pylori without developing to drug resistance. Fucoidan appears to be a strong anti-inflammation agent as manifested by the RAW264.7 cell model examination. Fucoidan can prohibit H. pylori adhesion to host cells, thereby reducing the infection rate by 60%, especially in post treatment in the AGS cell model assay. Mechanistically, fucoidan intervenes the adhesion of BabA and AlpA of H. pylori significantly lowering the total count of H. pylori and the level of IL-6 and TNF-α in vivo. These results all converge on the same fact that fucoidan is an effective agent in a position to protect the stomach from the H. pylori infection by reducing both the total count and induced inflammation.

scholarly journals Anti-Lewis X Antibody Promotes Helicobacter pylori Adhesion to Gastric Epithelial Cells

2007 ◽  
Vol 75 (6) ◽  
pp. 2661-2667 ◽  
Author(s):  
Shew-Meei Sheu ◽  
Bor-Shyang Sheu ◽  
Hsiao-Bai Yang ◽  
Huan-Yao Lei ◽  
Jiunn-Jong Wu
Keyword(s):  
Helicobacter Pylori ◽  
Bacterial Colonization ◽  
Host Cells ◽  
Adhesion Assay ◽  
Human Gastric Mucosa ◽  
Lewis X ◽  
Ags Cells ◽  
H Pylori ◽  
Bacterial Agglutination

ABSTRACT Lewis X (Lex) antigen is expressed on the human gastric mucosa and the O-specific chain of lipopolysaccharides of Helicobacter pylori. This antigen can induce autoantibodies, which may be involved in bacterial colonization and thus deserve further investigation. Flow cytometry was used to examine the effects of anti-Le monoclonal antibodies (MAbs) on H. pylori adhesion. A babA2 mutant was also constructed to evaluate the effect of an anti-Lex MAb on adhesion. The bacterial agglutination and in situ adhesion assays were used to confirm the anti-Lex MAb effect on H. pylori adhesion. This study revealed that an anti-Lex MAb, but not an anti-Leb MAb or an anti-Ley MAb, could enhance the adhesion of H. pylori strains that expressed high levels of Lex antigen to AGS cells. The enhancement was not found on an H. pylori strain with a low level of Lex antigen. Anti-Lex MAb could increase the adhesion of both the wild-type strain and its isogenic babA2 mutant to AGS cells. When AGS cells were pretreated with anti-Lex MAb, the adhesion of the babA2 mutant also increased. Only anti-Lex MAb could promote bacterial agglutination, and the in situ adhesion assay further confirmed that adding anti-Lex MAb resulted in denser bacterial adhesion on the gastric epithelia collected from clinical patients. These results suggest anti-Lex MAb could specifically enhance the adhesion abilities of H. pylori strains through a mechanism by which anti-Lex MAb promotes bacterial aggregation and mediates bivalent interaction (antigen-antibody-antigen) between bacteria and host cells.

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