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  1. Article ; Online: The gastric microbiome, its interaction with Helicobacter pylori, and its potential role in the progression to stomach cancer.

    Jennifer M Noto / Richard M Peek

    PLoS Pathogens, Vol 13, Iss 10, p e

    2017  Volume 1006573

    Keywords Immunologic diseases. Allergy ; RC581-607 ; Biology (General) ; QH301-705.5
    Language English
    Publishing date 2017-10-01T00:00:00Z
    Publisher Public Library of Science (PLoS)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Microbial Regulation of p53 Tumor Suppressor.

    Alexander I Zaika / Jinxiong Wei / Jennifer M Noto / Richard M Peek

    PLoS Pathogens, Vol 11, Iss 9, p e

    2015  Volume 1005099

    Abstract: p53 tumor suppressor has been identified as a protein interacting with the large T antigen produced by simian vacuolating virus 40 (SV40). Subsequent research on p53 inhibition by SV40 and other tumor viruses has not only helped to gain a better ... ...

    Abstract p53 tumor suppressor has been identified as a protein interacting with the large T antigen produced by simian vacuolating virus 40 (SV40). Subsequent research on p53 inhibition by SV40 and other tumor viruses has not only helped to gain a better understanding of viral biology, but also shaped our knowledge of human tumorigenesis. Recent studies have found, however, that inhibition of p53 is not strictly in the realm of viruses. Some bacterial pathogens also actively inhibit p53 protein and induce its degradation, resulting in alteration of cellular stress responses. This phenomenon was initially characterized in gastric epithelial cells infected with Helicobacter pylori, a bacterial pathogen that commonly infects the human stomach and is strongly linked to gastric cancer. Besides H. pylori, a number of other bacterial species were recently discovered to inhibit p53. These findings provide novel insights into host-bacteria interactions and tumorigenesis associated with bacterial infections.
    Keywords Immunologic diseases. Allergy ; RC581-607 ; Biology (General) ; QH301-705.5
    Subject code 572
    Language English
    Publishing date 2015-09-01T00:00:00Z
    Publisher Public Library of Science (PLoS)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Iron deficiency linked to altered bile acid metabolism promotes Helicobacter pylori–induced inflammation–driven gastric carcinogenesis

    Jennifer M. Noto / M. Blanca Piazuelo / Shailja C. Shah / Judith Romero-Gallo / Jessica L. Hart / Chao Di / James D. Carmichael / Alberto G. Delgado / Alese E. Halvorson / Robert A. Greevy / Lydia E. Wroblewski / Ayushi Sharma / Annabelle B. Newton / Margaret M. Allaman / Keith T. Wilson / M. Kay Washington / M. Wade Calcutt / Kevin L. Schey / Bethany P. Cummings /
    Charles R. Flynn / Joseph P. Zackular / Richard M. Peek Jr.

    The Journal of Clinical Investigation, Vol 132, Iss

    2022  Volume 10

    Abstract: Gastric carcinogenesis is mediated by complex interactions among Helicobacter pylori, host, and environmental factors. Here, we demonstrate that H. pylori augmented gastric injury in INS-GAS mice under iron-deficient conditions. Mechanistically, these ... ...

    Abstract Gastric carcinogenesis is mediated by complex interactions among Helicobacter pylori, host, and environmental factors. Here, we demonstrate that H. pylori augmented gastric injury in INS-GAS mice under iron-deficient conditions. Mechanistically, these phenotypes were not driven by alterations in the gastric microbiota; however, discovery-based and targeted metabolomics revealed that bile acids were significantly altered in H. pylori–infected mice with iron deficiency, with significant upregulation of deoxycholic acid (DCA), a carcinogenic bile acid. The severity of gastric injury was further augmented when H. pylori–infected mice were treated with DCA, and, in vitro, DCA increased translocation of the H. pylori oncoprotein CagA into host cells. Conversely, bile acid sequestration attenuated H. pylori–induced injury under conditions of iron deficiency. To translate these findings to human populations, we evaluated the association between bile acid sequestrant use and gastric cancer risk in a large human cohort. Among 416,885 individuals, a significant dose-dependent reduction in risk was associated with cumulative bile acid sequestrant use. Further, expression of the bile acid receptor transmembrane G protein–coupled bile acid receptor 5 (TGR5) paralleled the severity of carcinogenic lesions in humans. These data demonstrate that increased H. pylori–induced injury within the context of iron deficiency is tightly linked to altered bile acid metabolism, which may promote gastric carcinogenesis.
    Keywords Gastroenterology ; Infectious disease ; Medicine ; R
    Language English
    Publishing date 2022-05-01T00:00:00Z
    Publisher American Society for Clinical Investigation
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Helicobacter pylori perturbs iron trafficking in the epithelium to grow on the cell surface.

    Shumin Tan / Jennifer M Noto / Judith Romero-Gallo / Richard M Peek / Manuel R Amieva

    PLoS Pathogens, Vol 7, Iss 5, p e

    2011  Volume 1002050

    Abstract: Helicobacter pylori (Hp) injects the CagA effector protein into host epithelial cells and induces growth factor-like signaling, perturbs cell-cell junctions, and alters host cell polarity. This enables Hp to grow as microcolonies adhered to the host cell ...

    Abstract Helicobacter pylori (Hp) injects the CagA effector protein into host epithelial cells and induces growth factor-like signaling, perturbs cell-cell junctions, and alters host cell polarity. This enables Hp to grow as microcolonies adhered to the host cell surface even in conditions that do not support growth of free-swimming bacteria. We hypothesized that CagA alters host cell physiology to allow Hp to obtain specific nutrients from or across the epithelial barrier. Using a polarized epithelium model system, we find that isogenic ΔcagA mutants are defective in cell surface microcolony formation, but exogenous addition of iron to the apical medium partially rescues this defect, suggesting that one of CagA's effects on host cells is to facilitate iron acquisition from the host. Hp adhered to the apical epithelial surface increase basolateral uptake of transferrin and induce its transcytosis in a CagA-dependent manner. Both CagA and VacA contribute to the perturbation of transferrin recycling, since VacA is involved in apical mislocalization of the transferrin receptor to sites of bacterial attachment. To determine if the transferrin recycling pathway is involved in Hp colonization of the cell surface, we silenced transferrin receptor expression during infection. This resulted in a reduced ability of Hp to colonize the polarized epithelium. To test whether CagA is important in promoting iron acquisition in vivo, we compared colonization of Hp in iron-replete vs. iron-deficient Mongolian gerbils. While wild type Hp and ΔcagA mutants colonized iron-replete gerbils at similar levels, ΔcagA mutants are markedly impaired in colonizing iron-deficient gerbils. Our study indicates that CagA and VacA act in concert to usurp the polarized process of host cell iron uptake, allowing Hp to use the cell surface as a replicative niche.
    Keywords Immunologic diseases. Allergy ; RC581-607 ; Biology (General) ; QH301-705.5
    Subject code 570
    Language English
    Publishing date 2011-05-01T00:00:00Z
    Publisher Public Library of Science (PLoS)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article ; Online: Helicobacter pylori genetic diversification in the Mongolian gerbil model

    Amber C. Beckett / John T. Loh / Abha Chopra / Shay Leary / Aung Soe Lin / Wyatt J. McDonnell / Beverly R.E.A. Dixon / Jennifer M. Noto / Dawn A. Israel / Richard M. Peek Jr / Simon Mallal / Holly M. Scott Algood / Timothy L. Cover

    PeerJ, Vol 6, p e

    2018  Volume 4803

    Abstract: Helicobacter pylori requires genetic agility to infect new hosts and establish long-term colonization of changing gastric environments. In this study, we analyzed H. pylori genetic adaptation in the Mongolian gerbil model. This model is of particular ... ...

    Abstract Helicobacter pylori requires genetic agility to infect new hosts and establish long-term colonization of changing gastric environments. In this study, we analyzed H. pylori genetic adaptation in the Mongolian gerbil model. This model is of particular interest because H. pylori-infected gerbils develop a high level of gastric inflammation and often develop gastric adenocarcinoma or gastric ulceration. We analyzed the whole genome sequences of H. pylori strains cultured from experimentally infected gerbils, in comparison to the genome sequence of the input strain. The mean annualized single nucleotide polymorphism (SNP) rate per site was 1.5e−5, which is similar to the rates detected previously in H. pylori-infected humans. Many of the mutations occurred within or upstream of genes associated with iron-related functions (fur, tonB1, fecA2, fecA3, and frpB3) or encoding outer membrane proteins (alpA, oipA, fecA2, fecA3, frpB3 and cagY). Most of the SNPs within coding regions (86%) were non-synonymous mutations. Several deletion or insertion mutations led to disruption of open reading frames, suggesting that the corresponding gene products are not required or are deleterious during chronic H. pylori colonization of the gerbil stomach. Five variants (three SNPs and two deletions) were detected in isolates from multiple animals, which suggests that these mutations conferred a selective advantage. One of the mutations (FurR88H) detected in isolates from multiple animals was previously shown to confer increased resistance to oxidative stress, and we now show that this SNP also confers a survival advantage when H. pylori is co-cultured with neutrophils. Collectively, these analyses allow the identification of mutations that are positively selected during H. pylori colonization of the gerbil model.
    Keywords Helicobacter pylori ; Quasispecies ; Mutation ; Genetic diversity ; Evolution ; Animal models ; Medicine ; R ; Biology (General) ; QH301-705.5
    Subject code 570
    Language English
    Publishing date 2018-05-01T00:00:00Z
    Publisher PeerJ Inc.
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Article ; Online: Helicobacter pylori promotes the expression of Krüppel-like factor 5, a mediator of carcinogenesis, in vitro and in vivo.

    Jennifer M Noto / Tinatin Khizanishvili / Rupesh Chaturvedi / M Blanca Piazuelo / Judith Romero-Gallo / Alberto G Delgado / Shradha S Khurana / Johanna C Sierra / Uma S Krishna / Giovanni Suarez / Anne E Powell / James R Goldenring / Robert J Coffey / Vincent W Yang / Pelayo Correa / Jason C Mills / Keith T Wilson / Richard M Peek

    PLoS ONE, Vol 8, Iss 1, p e

    2013  Volume 54344

    Abstract: Helicobacter pylori is the strongest known risk factor for the development of gastric adenocarcinoma. H. pylori expresses a repertoire of virulence factors that increase gastric cancer risk, including the cag pathogenicity island and the vacuolating ... ...

    Abstract Helicobacter pylori is the strongest known risk factor for the development of gastric adenocarcinoma. H. pylori expresses a repertoire of virulence factors that increase gastric cancer risk, including the cag pathogenicity island and the vacuolating cytotoxin (VacA). One host element that promotes carcinogenesis within the gastrointestinal tract is Krüppel-like factor 5 (KLF5), a transcription factor that mediates key cellular functions. To define the role of KLF5 within the context of H. pylori-induced inflammation and injury, human gastric epithelial cells were co-cultured with the wild-type cag(+) H. pylori strain 60190. KLF5 expression was significantly upregulated following co-culture with H. pylori, but increased expression was independent of the cag island or VacA. To translate these findings into an in vivo model, C57BL/6 mice were challenged with the wild-type rodent-adapted cag(+) H. pylori strain PMSS1 or a PMSS1 cagE(-) isogenic mutant. Similar to findings in vitro, KLF5 staining was significantly enhanced in gastric epithelium of H. pylori-infected compared to uninfected mice and this was independent of the cag island. Flow cytometry revealed that the majority of KLF5(+) cells also stained positively for the stem cell marker, Lrig1, and KLF5(+)/Lrig1(+) cells were significantly increased in H. pylori-infected versus uninfected tissue. To extend these results into the natural niche of this pathogen, levels of KLF5 expression were assessed in human gastric biopsies isolated from patients with or without premalignant lesions. Levels of KLF5 expression increased in parallel with advancing stages of neoplastic progression, being significantly elevated in gastritis, intestinal metaplasia, and dysplasia compared to normal gastric tissue. These results indicate that H. pylori induces expression of KLF5 in gastric epithelial cells in vitro and in vivo, and that the degree of KLF5 expression parallels the severity of premalignant lesions in human gastric carcinogenesis.
    Keywords Medicine ; R ; Science ; Q
    Subject code 570
    Language English
    Publishing date 2013-01-01T00:00:00Z
    Publisher Public Library of Science (PLoS)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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