PRE CANCER LESION H. pylori CHRONIC INFECTION

ABSTRACTHelicobacter pyloriundergoes rapid microevolution during chronic infection, but very little is known about how this affects host interaction factors. The best-studied adhesin ofH. pyloriis BabA, which mediates binding to the blood group antigen Lewis b [Le(b)]. To study the dynamics of Le(b) adherence during human infection, we analyzed pairedH. pyloriisolates obtained sequentially from chronically infected individuals. A complete loss or significant reduction of Le(b) binding was observed in strains from 5 out of 23 individuals, indicating that the Le(b) binding phenotype is quite stable during chronic human infection. Sequence comparisons ofbabAidentified differences due to mutation and/or recombination in 12 out of 16 strain pairs analyzed. Most amino acid changes were found in the putative N-terminal extracellular adhesion domain. One strain pair that had changed from a Le(b) binding to a nonbinding phenotype was used to study the role of distinct sequence changes in Le(b) binding. By transformations of the nonbinding strain with ababAgene amplified from the binding strain,H. pyloristrains with mosaicbabAgenes were generated. Recombinants were enriched for a gain of Le(b) binding by biopanning or for BabA expression on the bacterial surface by pulldown assay. With this approach, we identified several amino acid residues affecting the strength of Le(b) binding. Additionally, the data showed that the C terminus of BabA, which is predicted to encode an outer membrane β-barrel domain, plays an essential role in the biogenesis of this protein.IMPORTANCEHelicobacter pyloricauses a chronic infection of the human stomach that can lead to ulcers and cancer. The bacterium can bind to gastric epithelial cells with specialized outer membrane proteins. The best-studied protein is the BabA adhesin which binds to the Lewis b blood group antigen. SinceH. pyloriis a bacterium with very high genetic variability, we asked whetherbabAevolves during chronic infection and how mutations or recombination inbabAaffect binding. We found that BabA-mediated adherence was stable in most individuals but observed a complete loss of binding or reduced binding in 22% of individuals. One strain pair in which binding was lost was used to generatebabAsequences that were mosaics of a functional allele and a nonfunctional allele, and the mosaic sequences were used to identify amino acids critically involved in binding of BabA to Lewis b.

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Development of a Tetracycline-Inducible Gene Expression System for the Study of Helicobacter pylori Pathogenesis

Applied and Environmental Microbiology ◽

10.1128/aem.02701-13 ◽

2013 ◽

Vol 79 (23) ◽

pp. 7351-7359 ◽

Cited By ~ 8

Author(s):

Aleksandra W. Debowski ◽

Phebe Verbrugghe ◽

Miriam Sehnal ◽

Barry James Marshall ◽

Mohammed Benghezal

Keyword(s):

Helicobacter Pylori ◽

Animal Models ◽

Chronic Infection ◽

Fluorescent Protein ◽

Expression System ◽

Content Type ◽

Conditional Expression ◽

H Pylori ◽

Green Fluorescent

ABSTRACTDeletion mutants and animal models have been instrumental in the study ofHelicobacter pyloripathogenesis. Conditional mutants, however, would enable the study of the temporal gene requirement duringH. pyloricolonization and chronic infection. To achieve this goal, we adapted theEscherichia coliTn10-derived tetracycline-inducible expression system for use inH. pylori. TheureApromoter was modified by inserting one or twotetoperators to generate tetracycline-responsive promoters, nameduPtetO, and these promoters were then fused to the reportergfpmut2 and inserted into different loci. The expression of the tetracycline repressor (tetR) was placed under the control of one of three promoters and inserted into the chromosome. Conditional expression of green fluorescent protein (GFP) in strains harboringtetRanduPtetO-GFPwas characterized by measuring GFP activity and by immunoblotting. The twotet-responsiveuPtetOpromoters differ in strength, and induction of these promoters was inducer concentration and time dependent, with maximum expression achieved after induction for 8 to 16 h. Furthermore, the chromosomal location of theuPtetO-GFPconstruct and the nature of the promoter driving expression oftetRinfluenced the strength of theuPtetOpromoters upon induction. Integration ofuPtetO-GFPandtetRconstructs at different genomic loci was stablein vivoand did not affect colonization. Finally, we demonstrate tetracycline-dependent induction of GFP expressionin vivoduring chronic infection. These results open new experimental avenues for dissectingH. pyloripathogenesis using animal models and for testing the roles of specific genes in colonization of, adaptation to, and persistence in the host.

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A Conventional Beagle Dog Model for Acute and Chronic Infection with Helicobacter pylori

Infection and Immunity ◽

10.1128/iai.67.6.3112-3120.1999 ◽

1999 ◽

Vol 67 (6) ◽

pp. 3112-3120 ◽

Cited By ~ 35

Author(s):

Giacomo Rossi ◽

Michela Rossi ◽

Claudia G. Vitali ◽

Damiano Fortuna ◽

Daniela Burroni ◽

...

Keyword(s):

Helicobacter Pylori ◽

Malt Lymphoma ◽

Chronic Infection ◽

Acute Infection ◽

Chronic Phase ◽

Human Infection ◽

Peptic Ulcers ◽

Treatment And Prevention ◽

History Of ◽

H Pylori

ABSTRACT Helicobacter pylori has been widely recognized as an important human pathogen responsible for chronic gastritis, peptic ulcers, gastric cancer, and mucosa-associated lymphoid tissue (MALT) lymphoma. Little is known about the natural history of this infection since patients are usually recognized as having the infection only after years or decades of chronic disease. Several animal models ofH. pylori infection, including those with different species of rodents, nonhuman primates, and germ-free animals, have been developed. Here we describe a new animal model in which the clinical, pathological, microbiological, and immunological aspects of human acute and chronic infection are mimicked and which allows us to monitor these aspects of infection within the same individuals. Conventional Beagle dogs were infected orally with a mouse-adapted strain of H. pylori and monitored for up to 24 weeks. Acute infection caused vomiting and diarrhea. The acute phase was followed by polymorphonuclear cell infiltration, interleukin 8 induction, mononuclear cell recruitment, and the appearance of a specific antibody response against H. pylori. The chronic phase was characterized by gastritis, epithelial alterations, superficial erosions, and the appearance of the typical macroscopic follicles that in humans are considered possible precursors of MALT lymphoma. In conclusion, infection in this model mimics closely human infection and allows us to study those phases that cannot be studied in humans. This new model can be a unique tool for learning more about the disease and for developing strategies for treatment and prevention.

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Gene structure of the Helicobacter pylori cytotoxin and evidence of its key role in gastric disease.

Journal of Experimental Medicine ◽

10.1084/jem.179.5.1653 ◽

1994 ◽

Vol 179 (5) ◽

pp. 1653-1658 ◽

Cited By ~ 383

Author(s):

J L Telford ◽

P Ghiara ◽

M Dell'Orco ◽

M Comanducci ◽

D Burroni ◽

...

Keyword(s):

Helicobacter Pylori ◽

Peptic Ulcer ◽

Gastric Mucosa ◽

Chronic Infection ◽

Gastric Disease ◽

Human Gastric Mucosa ◽

Gastric Lesions ◽

Gram Negative ◽

H Pylori ◽

Cytotoxin Gene

The gram negative, microaerophilic bacterium Helicobacter pylori colonizes the human gastric mucosa and establishes a chronic infection that is tightly associated with atrophic gastritis, peptic ulcer, and gastric carcinoma. Cloning of the H. pylori cytotoxin gene shows that the protein is synthesized as a 140-kD precursor that is processed to a 94-kD fully active toxin. Oral administration to mice of the purified 94-kD protein caused ulceration and gastric lesions that bear some similarities to the pathology observed in humans. The cloning of the cytotoxin gene and the development of a mouse model of human gastric disease will provide the basis for the understanding of H. pylori pathogenesis and the development of therapeutics and vaccines.

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Plasmacytoid dendritic cells-derived IFN-α is involved in Helicobacter pylori infection-induced differentiation of Schlafen 4–expressing myeloid-derived suppressor cells

Infection and Immunity ◽

10.1128/iai.00407-21 ◽

2021 ◽

Author(s):

Xiaodan Xiang ◽

Yaping Wu ◽

Hongwei Li ◽

Cun Li ◽

Lu Yan ◽

...

Keyword(s):

Bone Marrow ◽

Helicobacter Pylori ◽

Dendritic Cells ◽

Chronic Infection ◽

Suppressor Cells ◽

Neoplastic Transformation ◽

Plasmacytoid Dendritic Cells ◽

Myeloid Derived Suppressor Cells ◽

Wild Type ◽

H Pylori

During chronic infection with Helicobacter pylori , Schlafen 4-expressing myeloid-derived suppressor cells (SLFN4 + MDSCs) create a microenvironment favoring intestinal metaplasia and neoplastic transformation. SLFN4 can be induced by IFN-α, which is mainly secreted from plasmacytoid dendritic cells (pDCs). This study tested the hypothesis that Helicobacter pylori infection promotes SLFN4 + MDSC differentiation by inducing pDCs to secrete IFN-α. C57BL/6 mice were gavaged with H. pylori and infection lasted 2, 4, or 6 months. The mouse pDCs were isolated from the bone marrow from wild type C57BL/6J mice. The results showed that H. pylori infection increased the number of SLFN4 + MDSCs by inducing IFN-α expression in mice. Further mechanistic experiments unraveled that IFN-α induced SLFN4 transcription by binding to the SLFN4 promoter. Furthermore, H. pylori infection stimulated pDCs to secrete IFN-α by activating the TLR9-MyD88-IRF7 pathway. Collectively, Helicobacter pylori infection promotes SLFN4 + MDSC differentiation by inducing secretion of IFN-α from pDCs.

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Chronic Infection, a Neglected Cause Of Development Of Monoclonal Gammopathy Of Undetermined Significance (MGUS) and Myeloma

Blood ◽

10.1182/blood.v122.21.3116.3116 ◽

2013 ◽

Vol 122 (21) ◽

pp. 3116-3116 ◽

Cited By ~ 2

Author(s):

Delphine Feron ◽

Cathy Charlier ◽

Pauline Lehebel ◽

Denis Caillot ◽

Cedric Rossi ◽

...

Keyword(s):

Chronic Infection ◽

Monoclonal Gammopathy ◽

Conflicts Of Interest ◽

Core Protein ◽

Lymphocytic Leukemia ◽

Nuclear Antigen ◽

Human Herpes Virus 8 ◽

Epstein Barr ◽

H Pylori ◽

Undetermined Significance

Abstract Introduction Chronic infection can lead to B-cell malignancy via the direct transformation of infected B-lymphocytes or indirectly via cell transformation consecutive to chronic antigen-driven stimulation; the two mechanisms may occur simultaneously (Seifert et al. Methods Mol Biol 2013; 971:1; Hermouet et al. New Engl J Med 2003; 348:178; de Martel et al. Lancet Oncol 2012). Numerous studies have established that viruses (Epstein-Barr virus (EBV), human herpes virus 8, hepatitis C virus (HCV)) or bacteria (H. pylori) can induce lymphoma and chronic lymphocytic leukemia (CLL). In contrast, the role of chronic infection in the pathogenesis of myeloma is rarely investigated. Yet monoclonal immunoglobulins (mc Ig) that arise in HCV-positive myeloma patients typically target the virus (Bigot-Corbel et al. Blood 2008). Thus HCV infection may lead to monoclonal gammopathy of undetermined significance (MGUS) and eventually, myeloma. The present study shows that mc Ig also frequently target EBV, and less frequently, H. pylori. Methods In order to study the specificity of mc Ig, we designed a new assay based on a multiplexed infectious protein (MIP) microarray that combines representative panels of epitopes of a panel of germs that included HCV, EBV, H. pylori and 5 other germs, spotted in triplicate on nitrocellulose-coated slides (Feron et al. Anal Biochem 2013; 433:202). Slides were first incubated with either serum or purified mc Ig, then with an infrared dyed (IRD)-labeled secondary antibody, and fluorescence signals were detected and quantified. Results The specificity of purified mc Ig from 101 patients diagnosed with MGUS (n=34) or myeloma (n=67) was analysed using the 8-germ MIP microarray assay. We found that 20.6% of MGUS and 24.2% of myeloma patients (p=0.810) presented with a mc Ig that was specific for an antigen from HCV, EBV, or H. pylori. Indeed for 23/101 patients (22.7%), the purified mc Ig recognized HCV (n=10), EBV (n=11) or H. pylori (n=2). In contrast, none of the 101 mc Ig studied targeted CMV, a virus against which a majority of individuals possess antibodies. Interestingly, HCV- and EBV-specific mc Ig all targeted a single antigen. For 10/11 (91%) of the HCV-positive patients, the mc Ig was directed against HCV core protein. Regarding EBV-positive patients, the mc Ig specifically recognized EBV in 23% cases (11/59 tested), and in all cases the mc Ig targeted Epstein Barr nuclear antigen (EBNA). For 8% (2/25 tested) of H. pylori-positive patients, the mc Ig targeted different antigens of H. Pylori. The specificity of each mc Ig was confirmed by Western Blot analysis. Conclusion Altogether, 22.7% of the 101 MGUS and myeloma patients examined presented a mc Ig specific for HCV, EBV or H. pylori. Thus beside lymphoma and CLL, chronic infection by these 3 germs can also induce MGUS and eventually, trigger the pathogenic processes that lead to myeloma. Efforts should be made to identify the subsets of patients with mc Ig specific for HCV, EBV and H. pylori, preferably at the MGUS stage, as anti-infection treatment is expected to cure MGUS and prevent progression toward myeloma. Disclosures: No relevant conflicts of interest to declare.

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Acute and chronic infection of H. pylori caused the difference in apoptosis of gastric epithelial cells

Microbial Pathogenesis ◽

10.1016/j.micpath.2020.104717 ◽

2021 ◽

pp. 104717

Author(s):

Jia-Fei Liu ◽

Dong Guo ◽

En-Ming Kang ◽

Yu-Shan Wang ◽

Xiao-Zhong Gao ◽

...

Keyword(s):

Epithelial Cells ◽

Chronic Infection ◽

Gastric Epithelial Cells ◽

The Difference ◽

H Pylori

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A change of IL-2 and IL-4 production in patients withHelicobactor pyloriinfection

Mediators of Inflammation ◽

10.1155/s0962935195000469 ◽

1995 ◽

Vol 4 (4) ◽

pp. 289-292 ◽

Cited By ~ 1

Author(s):

X. G. Fan ◽

J. Yakoob ◽

X. J. Fan ◽

P. W. N. Keeling

Keyword(s):

Chronic Infection ◽

Cytokine Production ◽

Interleukin 2 ◽

Peripheral Blood Lymphocytes ◽

Immunological Mechanism ◽

Common Cause ◽

Helicobactor Pylori ◽

Gastric Biopsies ◽

H Pylori

Helicobactor pyloriis the most common cause of gastroduodenal inflammation. However, the exact immune pathogenesis is not fully understood. To look for evidence of the immunological mechanism inH. pyloriassociated disease, we measured cytokine interleukin-2 (IL-2) and IL-4 levels produced by peripheral blood lymphocytes (PBL) and gastric biopsies in 20 subjects with or withoutH. pyloriinfection.H. pylorican stimulate IL-2 and IL-4 production from PBL inH. pylorinegative as well asH. pyloripositive individuals. The spontaneous IL-2 production by PBL and gastric biopsies was greater (p < 0.0025, <0.001)inH. pylorinegative individuals than that inH. pyloriinfected patients. Increased IL-4 levels from PBL inH. pyloriinfected patients were found in the presence ofH. pylori(p < 0.0025). An increased spontaneous production of IL-4 from gastric biopsies was also observed inH. pyloriinfected patients (p < 0.025). In conclusion, an enhanced type 2 cytokine production was observed inH. pyloriinfected patients, which may be responsible forH. pylorichronic infection.

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NonhelicalHelicobacter pyloriMutants Show Altered Gland Colonization and Elicit Less Gastric Pathology than Helical Bacteria during Chronic Infection

Infection and Immunity ◽

10.1128/iai.00904-18 ◽

2019 ◽

Vol 87 (7) ◽

Cited By ~ 9

Author(s):

Laura E. Martínez ◽

Valerie P. O’Brien ◽

Christina K. Leverich ◽

Sue E. Knoblaugh ◽

Nina R. Salama

Keyword(s):

Chronic Infection ◽

Cell Shape ◽

Quantitative Imaging ◽

Acute Infection ◽

Three Dimensional ◽

Wild Type ◽

Content Type ◽

Tissue Interactions ◽

H Pylori ◽

Straight Rod

ABSTRACTHalf of all humans harborHelicobacter pyloriin their stomachs. Helical cell shape is thought to facilitateH. pylori’s ability to bore into the protective mucus layer in a corkscrew-like motion, thereby enhancing colonization of the stomach.H. pyloricell shape mutants show impaired colonization of the mouse stomach, highlighting the importance of cell shape in infection. To gain a deeper understanding of how helical cell morphology promotes host colonization byH. pylori, we used three-dimensional confocal microscopy to visualize the clinical isolate PMSS1 and an isogenic straight-rod mutant (Δcsd6) within thick longitudinal mouse stomach sections. We also performed volumetric image analysis to quantify the number of bacteria residing within corpus and antral glands in addition to measuring total CFU. We found that straight rods show attenuation during acute colonization of the stomach (1 day or 1 week postinfection) as measured by total CFU. Our quantitative imaging revealed that wild-type bacteria extensively colonized antral glands at 1 week postinfection, whilecsd6mutants showed variable colonization of the antrum at this time point. During chronic infection (1 or 3 months postinfection), total CFU were highly variable but similar for wild-type and straight rods. Both wild-type and straight rods persisted and expanded in corpus glands during chronic infection. However, the straight rods showed reduced inflammation and disease progression. Thus, helical cell shape contributes to tissue interactions that promote inflammation during chronic infection, in addition to facilitating niche acquisition during acute infection.

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