Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 56 (4), 1150-4

Diphenyleneiodonium Inhibits Apoptotic Cell Death of Gastric Epithelial Cells Infected With Helicobacter Pylori in a Korean Isolate

Affiliations

Diphenyleneiodonium Inhibits Apoptotic Cell Death of Gastric Epithelial Cells Infected With Helicobacter Pylori in a Korean Isolate

Soon Ok Cho et al. Yonsei Med J.

Abstract

NADPH oxidase produces a large amount of reactive oxygen species (ROS) in Helicobacter pylori (H. pylori)-induced gastric epithelial cells. Even though ROS mediate apoptotic cell death, direct involvement of NADPH oxidase on H. pylori-induced apoptosis remains unclear. Besides, H. pylori isolates show a high degree of genetic variability. The predominant genotype of H. pylori in Korea has been reported as cagA⁺, vacA s1b, m2, iceA genotype. Present study aims to investigate whether NADPH oxidase-generated ROS mediate apoptosis in human gastric epithelial AGS cells infected with H. pylori in a Korean isolate. AGS cells were pretreated with or without an NADPH oxidase inhibitor diphenyleneiodonium (DPI) and cultured in the presence of H. pylori at a bacterium/cell ratio of 300:1. Cell viability, hydrogen peroxide level, DNA fragmentation, and protein levels of p53, Bcl-2, and Bax were determined. Results showed that H. pylori inhibited cell viability with the density of H. pylori added to the cells. Inhibition of NADPH oxidase by DPI suppressed H. pylori-induced cell death, increased hydrogen peroxide, DNA fragmentation, and the ratio of Bax/Bcl-2, and p53 induction in AGS cells dose-dependently. The results suggest that targeting NADPH oxidase may prevent the development of gastric inflammation associated with H. pylori infection by suppressing abnormal apoptotic cell death of gastric epithelial cells.

Keywords: Helicobacter pylori; NADPH oxidase; apoptosis; diphenyleneiodonium; gastric epithelial cells.

Conflict of interest statement

The authors have no financial conflicts of interest.

Figures

Fig. 1
Fig. 1. Cell viability, hydrogen peroxide level, DNA fragmentation, and apoptotic indices of H. pylori-infected AGS cells treated with or without DPI. Prior to the experiment, the cells (1×105/mL/well) were cultured in the presence of H. pylori at a bacterium/cell ratio of 100:1, 300:1, and 500:1 for 24 h (A). For the following study on DPI, the cells were pre-treated with DPI (2.5 or 5 μM) for 2 h and infected with H. pylori at a bacterium/cell ratio of 300:1 for 2 h (hydrogen peroxide level) (B), 12 h (protein levels of p53, Bcl-2, and Bax) (E and F), and 24 h [DNA fragmentation (D) and cell viability (C)]. The values are expressed as means±SE of four different experiments. *p<0.05 versus none control (the cells without DPI and cultured in the absence of H. pylori), p<0.05 versus H. pylori control (the cells without DPI and cultured in the presence of H. pylori). AGS, gastric adenocarcinoma; DPI, diphenyleneiodonium; H. pylori, Helicobacter pylori.

Similar articles

See all similar articles

Cited by 1 PubMed Central articles

References

    1. Clément MV, Pervaiz S. Reactive oxygen intermediates regulate cellular response to apoptotic stimuli: an hypothesis. Free Radic Res. 1999;30:247–252. - PubMed
    1. Davies GR, Simmonds NJ, Stevens TR, Sheaff MT, Banatvala N, Laurenson IF, et al. Helicobacter pylori stimulates antral mucosal reactive oxygen metabolite production in vivo. Gut. 1994;35:179–185. - PMC - PubMed
    1. Nagata K, Yu H, Nishikawa M, Kashiba M, Nakamura A, Sato EF, et al. Helicobacter pylori generates superoxide radicals and modulates nitric oxide metabolism. J Biol Chem. 1998;273:14071–14073. - PubMed
    1. Bagchi D, Bhattacharya G, Stohs SJ. Production of reactive oxygen species by gastric cells in association with Helicobacter pylori. Free Radic Res. 1996;24:439–450. - PubMed
    1. Kawahara T, Kohjima M, Kuwano Y, Mino H, Teshima-Kondo S, Takeya R, et al. Helicobacter pylori lipopolysaccharide activates Rac1 and transcription of NADPH oxidase Nox1 and its organizer NOXO1 in guinea pig gastric mucosal cells. Am J Physiol Cell Physiol. 2005;288:C450–C457. - PubMed

Publication types

MeSH terms

Feedback