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

2005 ◽  
Vol 288 (2) ◽  
pp. C450-C457 ◽  
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.

Helicobacter pylorilipopolysaccharide induces apoptosis of cultured guinea pig gastric mucosal cells

2001 ◽  
Vol 281 (3) ◽  
pp. G726-G734 ◽  
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.

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

2005 ◽  
Vol 288 (2) ◽  
pp. G300-G307 ◽  
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.

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

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.

scholarly journals Helicobacter pylori Infection of Human and Murine Primary Gastric Cells

2004 ◽  
Vol 72 (9) ◽  
pp. 5464-5469 ◽  
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.

scholarly journals A Novel Line Immunoassay Based on Recombinant Virulence Factors Enables Highly Specific and Sensitive Serologic Diagnosis of Helicobacter pylori Infection

2013 ◽  
Vol 20 (11) ◽  
pp. 1703-1710 ◽  
Author(s):  
Luca Formichella ◽  
Laura Romberg ◽  
Christian Bolz ◽  
Michael Vieth ◽  
Michael Geppert ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Immune Responses ◽  
Virulence Factors ◽  
Gastrointestinal Disease ◽  
Individual Risk ◽  
Enzyme Linked Immunosorbent Assay ◽  
Type I ◽  
Serologic Test ◽  
Content Type ◽  
H Pylori

ABSTRACTHelicobacter pyloricolonizes half of the world's population, and infection can lead to ulcers, gastric cancer, and mucosa-associated lymphoid tissue (MALT) lymphoma. Serology is the only test applicable for large-scale, population-based screening, but current tests are hampered by a lack of sensitivity and/or specificity. Also, no serologic test allows the differentiation of type I and type II strains, which is important for predicting the clinical outcome.H. pylorivirulence factors have been associated with disease, but direct assessment of virulence factors requires invasive methods to obtain gastric biopsy specimens. Our work aimed at the development of a highly sensitive and specific, noninvasive serologic test to detect immune responses to importantH. pylorivirulence factors. This line immunoassay system (recomLine) is based on recombinant proteins. For this assay, six highly immunogenic virulence factors (CagA, VacA, GroEL, gGT, HcpC, and UreA) were expressed inEscherichia coli, purified, and immobilized to nitrocellulose membranes to detect serological immune responses in patient's sera. For the validation of the line assay, a cohort of 500 patients was screened, of which 290 (58.0%) wereH. pylorinegative and 210 (42.0%) were positive by histology. The assay showed sensitivity and specificity of 97.6% and 96.2%, respectively, compared to histology. In direct comparison to lysate blotting and enzyme-linked immunosorbent assay (ELISA), therecomLine assay had increased discriminatory power. For the assessment of individual risk for gastrointestinal disease, the test must be validated in a larger and defined patient cohort. Taking the data together, therecomLine assay provides a valuable tool for the diagnosis ofH. pyloriinfection.

Sign in / Sign up

Export Citation Format

Share Document