1. ¹Department of Microbiology, Hanyang University College of Medicine, Seoul, South Korea
2. ²Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, South Korea
3. ³Department of Biotechnology, Joongbu University, Choongnam, South Korea
4. ⁴School of Life Sciences and Biotechnology, Korea University, Seoul, South Korea
5. ⁵Department of Biomedical Engineering, Hanyang University, Seoul, South Korea
6. ⁶Department of Biochemistry and Molecular Biology, Hanyang University College of Medicine, Seoul, South Korea

Correspondence: Professor JM Kim, MD, Department of Microbiology, Hanyang University College of Medicine, 17 Haengdang-dong, Sungdong-gu, Seoul 133-791, Republic of Korea. E-mail: jungmogg@hanyang.ac.kr

Received 29 October 2007; Revised 23 January 2008; Accepted 26 January 2008; Published online 17 March 2008.

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 IB kinase (IKK) and heat shock protein 90 (Hsp90) to activate the nuclear factor-kappaB (NF-B) signaling pathway in human gastric epithelial cells infected with H. pylori. Conditioned medium (CM) containing Lactobacillus acidophilus-producing CLA significantly inhibited the activated NF-B 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- dramatically reduced H. pylori-induced IB phosphorylation, but siRNA for IKK- had little effect on IB phosphorylation, although the siRNA for IKK- significantly decreased IL-8 production. Furthermore, Hsp90 was associated with IKK- and IKK- in H. pylori-infected cells, and CM with CLA dissociated the complex between Hsp90 and IKK-. 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- and Hsp90 complex.