BACKGROUND AND AIMS: H. pylori infection results in an increased epithelial apoptosis in gastritis and duodenal ulcer patients. We investigated the role and type of activation of caspases in H. pylori-induced apoptosis in gastric epithelial cells. METHODS: Differentiated human gastric cancer cells (AGS) and human gastric mucous cell primary cultures were incubated with H. pylori for 0.5-24 hours in RPMI 1640 medium, and the effects on cell viability, epithelial apoptosis, and activity of caspases were monitored. Apoptosis was analyzed by detection of DNA-fragments by Hoechst stain(R), DNA-laddering, and Histone-ELISA. Activities of caspases were determined in fluorogenic assays and by Western blotting. Cleavage of BID and release of cytochrome c were analyzed by Western blot. Significance of caspase activation was investigated by preincubation of gastric epithelial cells with cell permeable specific caspase inhibitors. RESULTS: Incubation of gastric epithelial cells with H. pylori caused a time and concentration dependent induction of DNA fragmentation (3-fold increase), cleavage of BID, release of cytochrome c and a concomittant sequential activation of caspase-9 (4-fold), caspase-8 (2-fold), caspase-6 (2-fold), and caspase-3 (6-fold). No effects on caspase-1 and -7 were observed. Activation of caspases preceded the induction of DNA fragmentation. Apoptosis could be inhibited by prior incubation with the inhibitors of caspase-3, -8, and -9, but not with that of caspase-1. CONCLUSIONS: Activation of certain caspases and activation of the mitochondrial apoptotic pathway are essential for H. pylori induced apoptosis in gastric epithelial cells.
BACKGROUND AND AIMS: H. pyloriinfection results in an increased epithelial apoptosis in gastritis and duodenal ulcerpatients. We investigated the role and type of activation of caspases in H. pylori-induced apoptosis in gastric epithelial cells. METHODS: Differentiated humangastric cancer cells (AGS) and human gastric mucous cell primary cultures were incubated with H. pylori for 0.5-24 hours in RPMI 1640 medium, and the effects on cell viability, epithelial apoptosis, and activity of caspases were monitored. Apoptosis was analyzed by detection of DNA-fragments by Hoechst stain(R), DNA-laddering, and Histone-ELISA. Activities of caspases were determined in fluorogenic assays and by Western blotting. Cleavage of BID and release of cytochrome c were analyzed by Western blot. Significance of caspase activation was investigated by preincubation of gastric epithelial cells with cell permeable specific caspase inhibitors. RESULTS: Incubation of gastric epithelial cells with H. pylori caused a time and concentration dependent induction of DNA fragmentation (3-fold increase), cleavage of BID, release of cytochrome c and a concomittant sequential activation of caspase-9 (4-fold), caspase-8 (2-fold), caspase-6 (2-fold), and caspase-3 (6-fold). No effects on caspase-1 and -7 were observed. Activation of caspases preceded the induction of DNA fragmentation. Apoptosis could be inhibited by prior incubation with the inhibitors of caspase-3, -8, and -9, but not with that of caspase-1. CONCLUSIONS: Activation of certain caspases and activation of the mitochondrial apoptotic pathway are essential for H. pylori induced apoptosis in gastric epithelial cells.
Authors: Ali S Alfazari; Bayan Al-Dabbagh; Wafa Al-Dhaheri; Mazen S Taha; Ahmad A Chebli; Eva M Fontagnier; Zaher Koutoubi; Jose Kochiyi; Sherif M Karam; Abdul-Kader Souid Journal: World J Gastroenterol Date: 2015-01-14 Impact factor: 5.742
Authors: Bernd Schmeck; Ralph Gross; Phillipe Dje N'Guessan; Andreas C Hocke; Sven Hammerschmidt; Tim J Mitchell; Simone Rosseau; Norbert Suttorp; Stefan Hippenstiel Journal: Infect Immun Date: 2004-09 Impact factor: 3.441
Authors: Hassan Ashktorab; Rod H Dashwood; Mohaiza M Dashwood; Syed I Zaidi; Stephen M Hewitt; William R Green; Edward L Lee; Mohammadreza Daremipouran; Mehdi Nouraie; Reza Malekzadeh; Duane T Smoot Journal: Helicobacter Date: 2008-12 Impact factor: 5.753