Conjugated linoleic acids produced by Lactobacillus dissociates IKK-γ and Hsp90 complex in Helicobacter pylori-infected gastric epithelial cells

Abstract

Although probiotics have been reported to reduce the gastric inflammatory response to Helicobacter pylori infection, little information is available regarding the molecular mechanisms behind this reduction. This study investigates the role of conjugated linoleic acids (CLA) produced by probiotics in interactions of IkB kinase (IKK) and heat shock protein 90 (Hsp90) to activate the nuclear factor-kappaB (NF-kB) signaling pathway in human gastric epithelial cells infected with H. pylori. Conditioned medium (CM) containing Lactobacillus acidophilus-producing CLA significantly inhibited the activated NF-kB signals and the upregulated expression of interleukin-8 (IL-8) in MKN-45 cells infected with H. pylori. Pretreatment with CM with CLA attenuated the increased IKK activity induced by H. pylori. Transfection of siRNA for IKK-b dramatically reduced H. pylori-induced IkBa phosphorylation, but siRNA for IKK-a had little effect on IkBa phosphorylation, although the siRNA for IKK-a significantly decreased IL-8 production. Furthermore, Hsp90 was associated with IKK-a and IKK-g in H. pylori-infected cells, and CM with CLA dissociated the complex between Hsp90 and IKK-g. These results suggest that CLA produced by probiotics has anti-inflammatory activity in gastric epithelial cells infected with H. pylori via dissociation of the IKK-g and Hsp90 complex.

Bacteroides fragilis enterotoxin upregulates lipocalin-2 expression in intestinal epithelial cells

“…Transfection of the dominant-negative super-repressor or siRNA into cells was performed as described previously. 41 Cells were cultured in 6-well plates to 50-80% confluence and the cells were then transfected with the dominant-negative super-repressor, siRNA, or nonsilencing siRNA using Fugene 6 (Roche) as a transfection reagent. Briefly, 1 mg of siRNA or 1.5 mg plasmid DNA was diluted in serum-free medium to produce a final volume of 100 ml to which 3 ml of Fugene 6 was added before the mixture was incubated for 15 min at room temperature.…”

Dual effects of Helicobacter pylori vacuolating cytotoxin on human eosinophil apoptosis in early and late periods of stimulation

“…siRNA against c-IAP2 (Birc3) was purchased from Gibco-Invitrogen (Stealth Select RNAi TM siRNA, HSS100562, Carlsbad, CA, USA) [50]. Transfection was performed according to the procedure described previously [27,51].…”

Inhibition of apoptosis in Bacteroides fragilis enterotoxin‐stimulated intestinal epithelial cells through the induction of c‐IAP‐2

“…Specific proteins were detected using rabbit anti-human c-IAP2 (Santa Cruz Biotechnology, Inc, Santa Cruz, CA), rabbit antihuman c-IAP1 (Santa Cruz Biotechnology), rabbit anti-human phospho-ERK1/2 (Cell Signaling Technology, Inc., Beverly, MA), rabbit anti-human phospho-JNK (Cell Signaling Technology), rabbit anti-human phospho-p38 (Cell Signaling Technology) or mouse anti-human actin (Transduction Laboratories, Lexington, KY) as primary antibodies, and peroxidase-conjugated anti-rabbit or anti-mouse IgG as secondary antibodies. Specifically bound peroxidase of the secondary antibodies was detected by enhanced chemiluminescence (ECL system; Amersham Life Science, Buckinghamshire, England) and exposure to x-ray film [38]. To measure levels of phospho-p38, a p38 ELISA kit was used (Active Motif, Carlsbad, CA).…”