Glutamine protects gastric mucosal cells against ammonia-induced cell death: Implications for the reduction of mucosal injury during infection with H. pylori

The relationship between nonsteroidal anti-inflammatory drugs (NSAIDs) and Helicobacter pylori-induced gastric mucosal injury is still under debate. VacA toxin is an important H. pylori virulence factor that causes cytoplasmic vacuolation in cultured cells. Whether and how NSAIDs affect VacA-induced cytotoxicity is unclear. This study was designed to evaluate the effect of NSAIDs on H. pylori VacA toxin-induced cell vacuolation in human gastric mucosal cells in culture (MKN 28 cell line). Our data show that 1) NSAIDs (indomethacin, aspirin, and NS-398) inhibit VacA-induced cell vacuolation independently of inhibition of cell proliferation and prostaglandin synthesis; 2) NSAIDs impair vacuole development/maintenance without affecting cell binding and internalization of VacA; and 3) NSAIDs, as well as the chloride channel blocker 5-nitro-2-(3-phenylpropylamino) benzoic acid, also inhibit cell vacuolation induced by ammonia. We thus hypothesize that NSAIDs might protect MKN 28 cells against VacA-induced cytotoxicity by inhibiting VacA channel activity required for vacuole genesis.

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H. pylori modifies methylation of global genomic DNA and the gastrin gene promoter in gastric mucosal cells and gastric cancer cells

Microbial Pathogenesis ◽

10.1016/j.micpath.2017.05.003 ◽

2017 ◽

Vol 108 ◽

pp. 129-136 ◽

Cited By ~ 7

Author(s):

Yuan Xie ◽

Jian Jiang Zhou ◽

Yan Zhao ◽

Ting Zhang ◽

Liu Zheng Mei

Keyword(s):

Gastric Cancer ◽

Cancer Cells ◽

Genomic Dna ◽

Gene Promoter ◽

Gastric Cancer Cells ◽

Gastric Mucosal Cells ◽

Mucosal Cells ◽

H Pylori

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Cellular hypercalcemia is an early event in deoxycholate injury of rabbit gastric mucosal cells

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1995.269.2.g287 ◽

1995 ◽

Vol 269 (2) ◽

pp. G287-G296 ◽

Cited By ~ 4

Author(s):

A. J. Dziki ◽

S. Batzri ◽

J. W. Harmon ◽

M. Molloy

Keyword(s):

Cell Death ◽

Bile Salt ◽

Cell Injury ◽

Early Event ◽

Acetoxymethyl Ester ◽

Gastric Mucosal Cells ◽

Maximal Increase ◽

Fura 2 ◽

Gastric Cells ◽

Mucosal Cells

Ca2+ entry into the cell may be an early event in the pathophysiology of bile salt-induced gastric mucosal injury. The aim of this study was to characterize the rise in cytosolic free Ca2+ associated with bile salt injury and its association with cell injury and death. Rabbit gastric mucosal cells were preloaded with the Ca2+ indicator fura 2-acetoxymethyl ester (fura 2-AM) for 20 min at 37 degrees C and then exposed to graded concentrations of the bile salt deoxycholate (DC). Cytosolic free Ca2+ concentration ([Ca2+]i) was estimated by spectrofluorometry. The resting [Ca2+]i in gastric cells was 177 +/- 15 nM (n = 6). When cells were subjected to 0.5 mM DC, there was a time-dependent rise in [Ca2+]i. An increase in [Ca2+]i was observed within 2 min, at which time [Ca2+]i rose from 177 +/- 15 to 480 +/- 30 nM. The maximal increase in [Ca2+]i was observed after 20 min of exposure to 0.5 mM DC (639 +/- 49 nM), and [Ca2+]i remained unchanged for at least 2 h. The increase in [Ca2+]i depended on the concentration of DC. The minimum effective dose of DC was 0.2 mM, with which [Ca2+]i was increased by 1.6-fold (from 177 to 285 nM). At 0.5 mM DC also caused a rise in 45Ca2+ influx into the cells and reduced the viability of gastric cells from 96% to 58% at 2 h. The DC-induced rise in cytosolic free Ca2+ depended on the presence of extracellular Ca2+. In the absence of extracellular Ca2+ there was no rise in cytosolic Ca2+ and gastric cells were protected from cell death caused by DC. The DC-induced cell death was reduced from 26% to 10% and from 37% to 16% at 60 and 90 min, respectively, by removal of extracellular Ca2+. The association of DC with gastric cells was not altered by removing extracellular Ca2+. This suggests decreased DC-induced injury in the absence of extracellular Ca2+ is due to the protection from cellular hypercalcemia rather than some other mechanism related to reduced binding and/or association of DC to gastric cells. These experiments show that rising [Ca2+]i appears to be an early pathophysiological event in bile salt-induced cellular injury and that extracellular Ca2+ is critical to produce this effect.

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TNFα induced by H. Pylori phosphorylates JNK pathway which may induce apoptosis in gastric mucosal cells

Gastroenterology ◽

10.1016/s0016-5085(98)84747-1 ◽

1998 ◽

Vol 114 ◽

pp. A1168

Author(s):

A. Nagahara ◽

H. Miwa ◽

M. Hirose ◽

H. Misawa ◽

M. Kawabe ◽

...

Keyword(s):

Gastric Mucosal Cells ◽

Jnk Pathway ◽

Mucosal Cells ◽

H Pylori

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Helicobacter pylorilipopolysaccharide induces apoptosis of cultured guinea pig gastric mucosal cells

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.2001.281.3.g726 ◽

2001 ◽

Vol 281 (3) ◽

pp. G726-G734 ◽

Cited By ~ 16

Author(s):

Tsukasa Kawahara ◽

Shigetada Teshima ◽

Yuki Kuwano ◽

Ayuko Oka ◽

Kyoichi Kishi ◽

...

Keyword(s):

Growth Factor ◽

Cytochrome C ◽

Guinea Pig ◽

Primary Cultures ◽

Specific Inhibitor ◽

Caspase 8 ◽

Cytochrome C Release ◽

Gastric Mucosal Cells ◽

Mucosal Cells ◽

H Pylori

Helicobacter pylori lipopolysaccharide (LPS) is generally accepted as a low-toxicity virulence. Primary cultures of guinea pig gastric mucosal cells expressed the Toll-like receptor 4 and were sensitive to H. pylori LPS as well as Escherichia coli LPS. H. pylori LPS stimulated phosphorylation of transforming growth factor-β-activated kinase 1 (TAK1), TAK1-binding protein 1 (TAB1), and c-Jun NH2-terminal kinase (JNK) 2. H. pylori LPS at >2.1 endotoxin unit/ml (>1 ng/ml) activated caspase-8, stimulated cytochrome c release from mitochondria, and subsequently activated caspases-9 and -3, leading to apoptosis. Epidermal growth factor blocked all of these apoptotic processes and inhibited apoptosis, whereas it did not modify the phosphorylation of TAK1, TAB1, and JNK2. A comparatively specific inhibitor of caspase-8 or -9 blocked apoptosis, whereas cytochrome c release was prevented only with a caspase-8-like inhibitor. Our results suggest that caspase-8 and mitochondria may play crucial roles in H. pylori LPS-induced apoptosis and that this accelerated apoptosis may be involved in abnormal cell turnover of H. pylori-infected gastric mucosa.

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Ecabet sodium inhibitsHelicobacter pylorilipopolysaccharide-induced activation of NADPH oxidase 1 or apoptosis of guinea pig gastric mucosal cells

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00274.2004 ◽

2005 ◽

Vol 288 (2) ◽

pp. G300-G307 ◽

Cited By ~ 21

Author(s):

Kenji Kusumoto ◽

Tsukasa Kawahara ◽

Yuki Kuwano ◽

Shigetada Teshima-Kondo ◽

Kyoko Morita ◽

...

Keyword(s):

Guinea Pig ◽

Nadph Oxidase ◽

Transforming Growth Factor ◽

Polyacrylamide Gel Electrophoresis ◽

Northern Hybridization ◽

Gastric Mucosal Cells ◽

Ecabet Sodium ◽

Nadph Oxidase 1 ◽

Mucosal Cells ◽

H Pylori

Helicobacter pylori LPS activates a homolog of gp91phox, NADPH oxidase 1 (Nox1), in guinea pig gastric mucosal cells cultured in 10% FBS-containing medium. RT-PCR and Northern hybridization demonstrated that H. pylori LPS stimulated expression of Nox1 and a novel p47phoxhomolog (Noxo1) mRNAs with a peak at 4 h, followed by upregulation of superoxide anion (O2−) generation. Pretreatment with 10 mg/ml of a nonabsorbable antigastric ulcer drug, ecabet sodium (ecabet), completely blocked these two mRNA expressions and the upregulation of O2−production. Under low (0.1%)-FBS conditions, H. pylori LPS predominantly caused apoptosis of the cells. Ecabet completely blocked the LPS-triggered phosphorylation of transforming growth factor-β-activated kinase 1 (TAK1) and TAK1-binding protein 1, activation of caspase 8, loss of mitochondrial membrane potential, release of cytochrome c, activation of caspase 3, and appearance of apoptotic cells. In contrast, ecabet had no effect on ethanol- or etoposide-initiated apoptosis. The ecabet-pretreated cells exhibited the responsiveness to H. pylori LPS, similarly as untreated control cells did, when ecabet was removed by washing before the addition of H. pylori LPS. Incubation of H. pylori LPS with ecabet eliminated the toxic effects of the LPS, and nondenatured polyacrylamide gel electrophoresis indicated the formation of higher molecular mass complexes between H. pylori LPS and ecabet, suggesting that ecabet may interact with H. pylori LPS and block the activation of Toll-like receptor 4 (TLR4). Our results suggest that ecabet may suppress TLR4-mediated inflammation or accelerated apoptosis caused H. pylori infection.

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L-GLUTAMINE ERADICATES HELICOBACTER PYLORI GASTRITIS: A NOVEL CASE REPORT

Asian Journal of Pharmaceutical and Clinical Research ◽

10.22159/ajpcr.2017.v10i10.18704 ◽

2017 ◽

Vol 10 (10) ◽

pp. 13

Author(s):

Balaji Ommurugan ◽

Amita Priya

Keyword(s):

Helicobacter Pylori ◽

Sports Medicine ◽

Gastrointestinal Diseases ◽

Epithelial Proliferation ◽

Gastric Mucosal Cells ◽

First Case ◽

Mucosal Cells ◽

H Pylori ◽

Common Infection ◽

Helicobacter Pylori Gastritis

Helicobacter pylori is the most common infection causing gastrointestinal diseases in the developing countries. It causes oxidative damage to gastric mucosal cells thereby altering the epithelial proliferation of these cells. With proton pump inhibitors and antibiotics being the mainstay in the management of symptoms, preclinical and clinical research is making inroads with novel therapeutic innovations to target the bacterium with the help of antioxidants. Hence, we report the first case of the treatment and eradication of H. pylori using L-glutamine, a sports medicine supplement with high antioxidant potential.

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Helicobacter pylori lipopolysaccharide activates Rac1 and transcription of NADPH oxidase Nox1 and its organizer NOXO1 in guinea pig gastric mucosal cells

AJP Cell Physiology ◽

10.1152/ajpcell.00319.2004 ◽

2005 ◽

Vol 288 (2) ◽

pp. C450-C457 ◽

Cited By ~ 106

Author(s):

Tsukasa Kawahara ◽

Motoyuki Kohjima ◽

Yuki Kuwano ◽

Hisano Mino ◽

Shigetada Teshima-Kondo ◽

...

Keyword(s):

Helicobacter Pylori ◽

Guinea Pig ◽

Nadph Oxidase ◽

Primary Cultures ◽

Transcriptional Level ◽

Type I ◽

Gastric Mucosal Cells ◽

Mucosal Cells ◽

H Pylori ◽

Constitutively Active

Primary cultures of guinea pig gastric mucosal cells express NADPH oxidase 1 (Nox1), a homolog of gp91 phox, and produce superoxide anion (O2−) at a rate of ∼100 nmol·mg protein−1·h−1 in response to Helicobacter pylori ( H. pylori) lipopolysaccharide (LPS) from virulent type I strains. The upregulated O2− production also enhances H. pylori LPS-stimulated tumor necrosis factor-α or cyclooxygenase-2 mRNA expression, which suggests a potential role for Nox1 in the pathogenesis of H. pylori-associated diseases. The H. pylori LPS-stimulated O2− production in cultured gastric mucosal cells was inhibited by actinomycin D as well as cycloheximide, suggesting that the induction is regulated at the transcriptional level. The LPS treatment not only increased the Nox1 mRNA to a greater extent but also induced expression of the message-encoding, Nox-organizing protein 1 (NOXO1), a novel p47 phox homolog required for Nox1 activity. In addition, H. pylori LPS activated Rac1; i.e., it converted Rac1 to the GTP-bound state. A phosphoinositide 3-kinase inhibitor, LY-294002, blocked H. pylori LPS-induced Rac1 activation and O2− generation without interfering with the expression of Nox1 and NOXO1 mRNA. O2− production inhibited by LY-294002 was completely restored by transfection of an adenoviral vector encoding a constitutively active Rac1 but not an inactive Rac1 or a constitutively active Cdc42. These findings indicate that Rac1 plays a crucial role in Nox1 activation. Thus the H. pylori LPS-stimulated O2− production in gastric mucosal cells appears to require two distinct events: 1) transcriptional upregulation of Nox1 and NOXO1 and 2) activation of Rac1.

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Helicobacter pylori Infection of Human and Murine Primary Gastric Cells

Infection and Immunity ◽

10.1128/iai.72.9.5464-5469.2004 ◽

2004 ◽

Vol 72 (9) ◽

pp. 5464-5469 ◽

Cited By ~ 3

Author(s):

Marguerite Clyne ◽

Brendan Drumm

Keyword(s):

Animal Model ◽

Helicobacter Pylori ◽

Helicobacter Pylori Infection ◽

Gastric Mucosal Cells ◽

Cell Lysates ◽

Gastric Cells ◽

Mucosal Cells ◽

H Pylori

ABSTRACT The effect of Helicobacter pylori infection on human and murine primary gastric cells was determined. CagA was phosphorylated following adherence of H. pylori to primary human gastric cells. However, it did not adhere to human primary duodenal cells or murine gastric cells, and CagA could not be detected in cell lysates. Identification of an easily available animal model of infection in which the organism adheres to gastric mucosal cells would enhance studies of the virulence of H. pylori.

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