Modification of the Gastric Mucosal Microbiota by a Strain-Specific Helicobacter pylori Oncoprotein and Carcinogenic Histologic Phenotype

ABSTRACT Helicobacter pylori is the strongest risk factor for gastric adenocarcinoma; however, most infected individuals never develop this malignancy. Strain-specific microbial factors, such as the oncoprotein CagA, as well as environmental conditions, such as iron deficiency, augment cancer risk. Importantly, dysbiosis of the gastric microbiota is also associated with gastric cancer. To investigate the combinatorial effects of these determinants in an in vivo model of gastric cancer, Mongolian gerbils were infected with the carcinogenic cag+ H. pylori strain 7.13 or a 7.13 cagA isogenic mutant, and microbial DNA extracted from gastric tissue was analyzed by 16S rRNA sequencing. Infection with H. pylori significantly increased gastric inflammation and injury, decreased α-diversity, and altered microbial community structure in a cagA-dependent manner. The effect of iron deficiency on gastric microbial communities was also investigated within the context of infection. H. pylori-induced injury was augmented under conditions of iron deficiency, but despite differences in gastric pathology, there were no significant differences in α- or β-diversity, phyla, or operational taxonomic unit (OTU) abundance among infected gerbils maintained on iron-replete or iron-depleted diets. However, when microbial composition was stratified based solely on the severity of histologic injury, significant differences in α- and β-diversity were present among gerbils harboring premalignant or malignant lesions compared to gerbils with gastritis alone. This study demonstrates that H. pylori decreases gastric microbial diversity and community structure in a cagA-dependent manner and that as carcinogenesis progresses, there are corresponding alterations in community structure that parallel the severity of disease. IMPORTANCE Microbial communities are essential for the maintenance of human health, and when these communities are altered, hosts can become susceptible to inflammation and disease. Dysbiosis contributes to gastrointestinal cancers, and specific bacterial species are associated with this phenotype. This study uses a robust and reproducible animal model to demonstrate that H. pylori infection induces gastric dysbiosis in a cagA-dependent manner and further that dysbiosis and altered microbial community structure parallel the severity of H. pylori-induced gastric injury. Ultimately, such models of H. pylori infection and cancer that can effectively evaluate multiple determinants simultaneously may yield effective strategies for manipulating the gastric microbiota to prevent the development of gastric cancer.

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The Helicobacter pylori Autotransporter ImaA (HP0289) Modulates the Immune Response and Contributes to Host Colonization

Infection and Immunity ◽

10.1128/iai.00312-12 ◽

2012 ◽

Vol 80 (7) ◽

pp. 2286-2296 ◽

Cited By ~ 13

Author(s):

William E. Sause ◽

Andrea R. Castillo ◽

Karen M. Ottemann

Keyword(s):

Immune Response ◽

Helicobacter Pylori ◽

Membrane Protein ◽

Outer Membrane ◽

Outer Membrane Protein ◽

Dependent Manner ◽

Wild Type ◽

Content Type ◽

H Pylori ◽

Murine Infections

ABSTRACTThe human pathogenHelicobacter pyloriemploys a diverse collection of outer membrane proteins to colonize, persist, and drive disease within the acidic gastric environment. In this study, we sought to elucidate the function of the host-induced geneHP0289, which encodes an uncharacterized outer membrane protein. We first generated an isogenicH. pylorimutant that lacksHP0289and found that the mutant has a colonization defect in single-strain infections and is greatly outcompeted in mouse coinfection experiments with wild-typeH. pylori. Furthermore, we used protease assays and biochemical fractionation coupled with an HP0289-targeted peptide antibody to verify that the HP0289 protein resides in the outer membrane. Our previous findings showed that theHP0289promoter is upregulated in the mouse stomach, and here we demonstrate thatHP0289expression is induced under acidic conditions in an ArsRS-dependent manner. Finally, we have shown that theHP0289mutant induces greater expression of the chemokine interleukin-8 (IL-8) and the cytokine tumor necrosis factor alpha (TNF-α) in gastric carcinoma cells (AGS). Similarly, transcription of the IL-8 homolog keratinocyte-derived chemokine (KC) is elevated in murine infections with the HP0289 mutant than in murine infections with wild-typeH. pylori. On the basis of this phenotype, we renamed HP0289 ImaA forimmunomodulatoryautotransporter protein. Our work has revealed that genes inducedin vivoplay an important role inH. pyloripathogenesis. Specifically, the outer membrane protein ImaA modulates a component of the host inflammatory response, and thus may allowH. pylorito fine tune the host immune response based on ImaA expression.

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Systems Modeling of the Role of Interleukin-21 in the Maintenance of Effector CD4+ T Cell Responses during Chronic Helicobacter pylori Infection

mBio ◽

10.1128/mbio.01243-14 ◽

2014 ◽

Vol 5 (4) ◽

Cited By ~ 36

Author(s):

Adria Carbo ◽

Danyvid Olivares-Villagómez ◽

Raquel Hontecillas ◽

Josep Bassaganya-Riera ◽

Rupesh Chaturvedi ◽

...

Keyword(s):

Gastric Cancer ◽

Helicobacter Pylori ◽

T Cell ◽

Wild Type ◽

Content Type ◽

Interleukin 21 ◽

H Pylori ◽

Deficient Mice

ABSTRACTThe development of gastritis duringHelicobacter pyloriinfection is dependent on an activated adaptive immune response orchestrated by T helper (Th) cells. However, the relative contributions of the Th1 and Th17 subsets to gastritis and control of infection are still under investigation. To investigate the role of interleukin-21 (IL-21) in the gastric mucosa duringH. pyloriinfection, we combined mathematical modeling of CD4+T cell differentiation within vivomechanistic studies. We infected IL-21-deficient and wild-type mice withH. pyloristrain SS1 and assessed colonization, gastric inflammation, cellular infiltration, and cytokine profiles. ChronicallyH. pylori-infected IL-21-deficient mice had higherH. pyloricolonization, significantly less gastritis, and reduced expression of proinflammatory cytokines and chemokines compared to these parameters in infected wild-type littermates. Thesein vivodata were used to calibrate anH. pyloriinfection-dependent, CD4+T cell-specific computational model, which then described the mechanism by which IL-21 activates the production of interferon gamma (IFN-γ) and IL-17 during chronicH. pyloriinfection. The model predicted activated expression of T-bet and RORγt and the phosphorylation of STAT3 and STAT1 and suggested a potential role of IL-21 in the modulation of IL-10. Driven by our modeling-derived predictions, we found reduced levels of CD4+splenocyte-specifictbx21androrcexpression, reduced phosphorylation of STAT1 and STAT3, and an increase in CD4+T cell-specific IL-10 expression inH. pylori-infected IL-21-deficient mice. Our results indicate that IL-21 regulates Th1 and Th17 effector responses during chronicH. pyloriinfection in a STAT1- and STAT3-dependent manner, therefore playing a major role controllingH. pyloriinfection and gastritis.IMPORTANCEHelicobacter pyloriis the dominant member of the gastric microbiota in more than 50% of the world’s population.H. pyloricolonization has been implicated in gastritis and gastric cancer, as infection withH. pyloriis the single most common risk factor for gastric cancer. Current data suggest that, in addition to bacterial virulence factors, the magnitude and types of immune responses influence the outcome of colonization and chronic infection. This study uses a combined computational and experimental approach to investigate how IL-21, a proinflammatory T cell-derived cytokine, maintains the chronic proinflammatory T cell immune response driving chronic gastritis duringH. pyloriinfection. This research will also provide insight into a myriad of other infectious and immune disorders in which IL-21 is increasingly recognized to play a central role. The use of IL-21-related therapies may provide treatment options for individuals chronically colonized withH. pylorias an alternative to aggressive antibiotics.

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Role of Interleukin-32 in Helicobacter pylori-Induced Gastric Inflammation

Infection and Immunity ◽

10.1128/iai.00637-12 ◽

2012 ◽

Vol 80 (11) ◽

pp. 3795-3803 ◽

Cited By ~ 31

Author(s):

Kosuke Sakitani ◽

Yoshihiro Hirata ◽

Yoku Hayakawa ◽

Takako Serizawa ◽

Wachiko Nakata ◽

...

Keyword(s):

Gastric Cancer ◽

Helicobacter Pylori ◽

Gastric Mucosa ◽

Cell Lines ◽

Inflammatory Diseases ◽

Nuclear Factor Κb ◽

Gastric Disease ◽

Ags Cells ◽

Content Type ◽

H Pylori

ABSTRACTHelicobacter pyloriinfection is associated with gastritis and gastric cancer. AnH. pylorivirulence factor, thecagpathogenicity island (PAI), is related to host cell cytokine induction and gastric inflammation. Since elucidation of the mechanisms of inflammation is important for therapy, the associations between cytokines and inflammatory diseases have been investigated vigorously. Levels of interleukin-32 (IL-32), a recently described inflammatory cytokine, are increased in various inflammatory diseases, such as rheumatoid arthritis and Crohn's disease, and in malignancies, including gastric cancer. In this report, we examined IL-32 expression in human gastric disease. We also investigated the function of IL-32 in activation of the inflammatory cytokines in gastritis. IL-32 expression paralleled human gastric tissue pathology, with low IL-32 expression inH. pylori-uninfected gastric mucosa and higher expression levels in gastritis and gastric cancer tissues.H. pyloriinfection increased IL-32 expression in human gastric epithelial cell lines.H. pylori-induced IL-32 expression was dependent on the bacterialcagPAI genes and on activation of nuclear factor κB (NF-κB). IL-32 expression induced byH. pyloriwas not detected in the supernatant of AGS cells but was found in the cytosol. Expression of theH. pylori-induced cytokines CXCL1, CXCL2, and IL-8 was decreased in IL-32-knockdown AGS cell lines compared to a control AGS cell line. We also found that NF-κB activation was decreased inH. pylori-infected IL-32-knockdown cells. These results suggest that IL-32 has important functions in the regulation of cytokine expression inH. pylori-infected gastric mucosa.

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Dietary Composition Influences Incidence of Helicobacter pylori-Induced Iron Deficiency Anemia and Gastric Ulceration

Infection and Immunity ◽

10.1128/iai.00479-16 ◽

2016 ◽

Vol 84 (12) ◽

pp. 3338-3349 ◽

Cited By ~ 11

Author(s):

Amber C. Beckett ◽

M. Blanca Piazuelo ◽

Jennifer M. Noto ◽

Richard M. Peek ◽

M. Kay Washington ◽

...

Keyword(s):

Helicobacter Pylori ◽

Iron Deficiency ◽

Iron Deficiency Anemia ◽

Gastric Ulceration ◽

High Salt ◽

Gastric Ulcers ◽

Deficiency Anemia ◽

Content Type ◽

H Pylori

Epidemiologic studies have provided conflicting data regarding an association betweenHelicobacter pyloriinfection and iron deficiency anemia (IDA) in humans. Here, a Mongolian gerbil model was used to investigate a potential role ofH. pyloriinfection, as well as a possible role of diet, inH. pylori-associated IDA. Mongolian gerbils (eitherH. pyloriinfected or uninfected) received a normal diet or one of three diets associated with increasedH. pylorivirulence: high-salt, low-iron, or a combination of a high-salt and low-iron diet. In an analysis of all infected animals compared to uninfected animals (independent of diet),H. pylori-infected gerbils had significantly lower hemoglobin values than their uninfected counterparts at 16 weeks postinfection (P< 0.0001). The mean corpuscular volume (MCV) and serum ferritin values were significantly lower inH. pylori-infected gerbils than in uninfected gerbils, consistent with IDA. Leukocytosis and thrombocytosis were also detected in infected gerbils, indicating the presence of a systemic inflammatory response. In comparison to uninfected gerbils,H. pylori-infected gerbils had a higher gastric pH, a higher incidence of gastric ulcers, and a higher incidence of fecal occult blood loss. Anemia was associated with the presence of gastric ulceration but not gastric cancer. Infected gerbils consuming diets with a high salt content developed gastric ulcers significantly more frequently than gerbils consuming a normal-salt diet, and the lowest hemoglobin levels were in infected gerbils consuming a high-salt/low-iron diet. These data indicate thatH. pyloriinfection can cause IDA and that the composition of the diet influences the incidence and severity ofH. pylori-induced IDA.

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Phylogeographic Origin of Helicobacter pylori Determines Host-Adaptive Responses upon Coculture with Gastric Epithelial Cells

Infection and Immunity ◽

10.1128/iai.01182-12 ◽

2013 ◽

Vol 81 (7) ◽

pp. 2468-2477 ◽

Cited By ~ 16

Author(s):

Alexander Sheh ◽

Rupesh Chaturvedi ◽

D. Scott Merrell ◽

Pelayo Correa ◽

Keith T. Wilson ◽

...

Keyword(s):

Gene Expression ◽

Gastric Cancer ◽

Helicobacter Pylori ◽

Epithelial Cells ◽

Gastric Disease ◽

Gastric Epithelial Cells ◽

Gastric Cancer Risk ◽

Content Type ◽

H Pylori ◽

Induced Apoptosis

ABSTRACTWhileHelicobacter pyloriinfects over 50% of the world's population, the mechanisms involved in the development of gastric disease are not fully understood. Bacterial, host, and environmental factors play a role in disease outcome. To investigate the role of bacterial factors inH. pyloripathogenesis, global gene expression of sixH. pyloriisolates was analyzed during coculture with gastric epithelial cells. Clustering analysis of six Colombian clinical isolates from a region with low gastric cancer risk and a region with high gastric cancer risk segregated strains based on their phylogeographic origin. One hundred forty-six genes had increased expression in European strains, while 350 genes had increased expression in African strains. Differential expression was observed in genes associated with motility, pathogenicity, and other adaptations to the host environment. European strains had greater expression of the virulence factorscagA,vacA, andbabBand were associated with increased gastric histologic lesions in patients. In AGS cells, European strains promoted significantly higher interleukin-8 (IL-8) expression than did African strains. African strains significantly induced apoptosis, whereas only one European strain significantly induced apoptosis. Our data suggest that gene expression profiles of clinical isolates can discriminate strains by phylogeographic origin and that these profiles are associated with changes in expression of the proinflammatory and protumorigenic cytokine IL-8 and levels of apoptosis in host epithelial cells. These findings support the hypothesis that bacterial factors determined by the phylogeographic origin ofH. pyloristrains may promote increased gastric disease.

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Differential Roles of ASK1 and TAK1 in Helicobacter pylori-Induced Cellular Responses

Infection and Immunity ◽

10.1128/iai.00914-13 ◽

2013 ◽

Vol 81 (12) ◽

pp. 4551-4560 ◽

Cited By ~ 18

Author(s):

Yoku Hayakawa ◽

Yoshihiro Hirata ◽

Hiroto Kinoshita ◽

Kosuke Sakitani ◽

Hayato Nakagawa ◽

...

Keyword(s):

Helicobacter Pylori ◽

Epithelial Cells ◽

Signaling Pathway ◽

Critical Role ◽

Cellular Responses ◽

Mapk Signaling ◽

Dependent Manner ◽

Content Type ◽

H Pylori ◽

Jnk Activation

ABSTRACTThe mitogen-activated protein kinase (MAPK) signaling pathway regulates various cellular functions, including those induced byHelicobacter pylori. TAK1 is an upstream MAPK kinase kinase (MAP3K) required forH. pylori-induced MAPK and NF-κB activation, but it remains unclear whether other MAP3Ks are involved inH. pylori-induced cellular responses. In this study, we focused on the MAP3K ASK1, which plays a critical role in gastric tumorigenesis. In gastric epithelial cells,H. pyloriactivates ASK1 in a reactive oxygen species (ROS)- andcagpathogenicity island-dependent manner, and ASK1 regulates sustained JNK activation and apoptosis induced byH. pylori. In contrast, TAK1 regulatesH. pylori-mediated early JNK activation and cytokine production. We also found reciprocal regulation between ASK1 and TAK1 inH. pylori-related responses, whereby inhibition of TAK1 or downstream p38 MAPK activates ASK1 through ROS production, and ASK1 suppresses TAK1 and downstream NF-κB activation. We identified ROS/ASK1/JNK as a new signaling pathway induced byH. pylori, which regulates apoptotic cell death. The balance of ASK1-induced apoptosis and TAK1-induced antiapoptotic or inflammatory responses may determine the fate of epithelial cells infected withH. pyloriand thus be involved in the pathogenesis of gastritis and gastric cancer.

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The Degree of Helicobacter pylori-Triggered Inflammation Is Manipulated by Preinfection Host Microbiota

Infection and Immunity ◽

10.1128/iai.00044-13 ◽

2013 ◽

Vol 81 (5) ◽

pp. 1382-1389 ◽

Cited By ~ 46

Author(s):

Annah S. Rolig ◽

Cynthia Cech ◽

Ethan Ahler ◽

J. Elliot Carter ◽

Karen M. Ottemann

Keyword(s):

Helicobacter Pylori ◽

Bacterial Communities ◽

Severe Disease ◽

Disease Outcome ◽

Gastric Tissue ◽

T Helper ◽

Content Type ◽

H Pylori ◽

Primary Risk Factor ◽

Gastric Microbiota

ABSTRACTHelicobacter pyloriinfects over 3 billion people worldwide and is the primary risk factor for gastric cancer. Most individuals infected withH. pyloridevelop only asymptomatic gastritis; however, some develop ulcers or gastric adenocarcinoma. We demonstrate that one previously unappreciated parameter influencingH. pyloridisease outcome is variation in the preinfection host microbiota. Utilizing a mouse model, we altered the microbiota by antibiotic treatment and found that these alterations resulted in significantly loweredH. pylori-triggered inflammation. Specifically, antibiotic pretreatment reduced CD4+T-helper cells andIfnγ transcript levels in gastric tissue afterH. pyloriinfection. The bacterial communities in mice with a reduced response toH. pyloridisplayed many differences from those in untreated mice, including significantly more cluster IV and XIVaClostridiumspp., bacteria known to influence inflammation via regulatory T cell populations. Our findings suggest that microbiota composition, perhapsClostridiumspp., contributes to the variable disease outcome ofH. pyloriinfection by altering the recruitment of CD4+T cells to the gastric compartment. Our results suggest that gastric microbiota could be used as a diagnostic tool to determine which patients are at risk for developing severe disease.

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Gastric Microbiota in Helicobacter pylori-Negative and -Positive Gastritis Among High Incidence of Gastric Cancer Area

Cancers ◽

10.3390/cancers11040504 ◽

2019 ◽

Vol 11 (4) ◽

pp. 504 ◽

Cited By ~ 14

Author(s):

Boldbaatar Gantuya ◽

Hashem B. El-Serag ◽

Takashi Matsumoto ◽

Nadim J. Ajami ◽

Khasag Oyuntsetseg ◽

...

Keyword(s):

Gastric Cancer ◽

Helicobacter Pylori ◽

Bacterial Species ◽

Rrna Gene ◽

Linear Discriminant ◽

Haemophilus Parainfluenzae ◽

Increased Risk ◽

Comparison Groups ◽

H Pylori ◽

Gastric Microbiota

Helicobacter pylori (H. pylori) related chronic gastritis is a well-known major etiological factor for gastric cancer development. However, H. pylori-negative gastritis (HpN) is not well described. We aimed to examine gastric mucosal microbiota in HpN compared to H. pylori-positive gastritis (HpP) and H. pylori-negative non-gastritis group (control). Here, we studied 11 subjects with HpN, 40 with HpP and 24 controls. We performed endoscopy with six gastric biopsies. Comparison groups were defined based on strict histological criteria for the disease and H. pylori diagnosis. We used 16S rRNA gene amplicon sequencing to profile the gastric microbiota according to comparison groups. These results demonstrate that the HpP group had significantly lower bacterial richness by the operational taxonomic unit (OTU) counts, and Shannon and Simpson indices as compared to HpN or controls. The linear discriminant analysis effect size analysis showed the enrichment of Firmicutes, Fusobacteria, Bacteroidetes and Actinobacteria at phylum level in the HpN group. In the age-adjusted multivariate analysis, Streptococcus sp. and Haemophilus parainfluenzae were at a significantly increased risk for HpN (odds ratio 18.9 and 12.3, respectively) based on abundance. Treponema sp. was uniquely found in HpN based on occurrence. In this paper, we conclude that Streptococcus sp., Haemophilus parainfluenzae and Treponema sp. are candidate pathogenic bacterial species for HpN. These results if confirmed may have important clinical implications.

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Complete Genome Sequence of Helicobacter pylori Strain ATCC 43504, a Type Strain That Can Infect Gerbils

Microbiology Resource Announcements ◽

10.1128/mra.00105-20 ◽

2020 ◽

Vol 9 (18) ◽

Author(s):

Ryo Kinoshita-Daitoku ◽

Yoshitoshi Ogura ◽

Kotaro Kiga ◽

Fumito Maruyama ◽

Tomoyo Kondo ◽

...

Keyword(s):

Gastric Cancer ◽

Helicobacter Pylori ◽

Cancer Patient ◽

Genome Sequence ◽

Complete Genome Sequence ◽

Complete Genome ◽

Type Strain ◽

Strain Atcc ◽

Content Type ◽

H Pylori

Helicobacter pylori ATCC 43504 is a type strain isolated from a gastric cancer patient in Australia and is commonly used for pathogenicity studies. In this study, we report the complete genome sequence of a strain that can infect gerbils. The data provide a basis for future H. pylori research.

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Helicobacter pylori and Epstein-Barr Virus Coinfection Stimulates Aggressiveness in Gastric Cancer through the Regulation of Gankyrin

mSphere ◽

10.1128/msphere.00751-21 ◽

2021 ◽

Author(s):

Dharmendra Kashyap ◽

Budhadev Baral ◽

Shweta Jakhmola ◽

Anil Kumar Singh ◽

Hem Chandra Jha

Keyword(s):

Gastric Cancer ◽

Helicobacter Pylori ◽

Epithelial Cells ◽

Epstein Barr Virus ◽

Synergistic Effects ◽

Gastric Epithelial Cells ◽

Content Type ◽

Barr Virus ◽

Epstein Barr ◽

H Pylori

In the present study, we evaluated the synergistic effects of EBV and H. pylori infection on gastric epithelial cells in various coinfection models. These coinfection models were among the first to depict the exposures of gastric epithelial cells to EBV followed by H. pylori ; however, coinfection models exist that narrated the scenario upon exposure to H. pylori followed by that to EBV.

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