Title Cot kinase plays a critical role in Helicobacter pylori-induced IL-8 expression
Author Sungil Jang1, Jinmoon Kim1, and Jeong-Heon Cha1,2*
Address 1Department of Oral Biology, Oral Science Research Center, BK21 Plus Project, Yonsei University College of Dentistry, Seoul 03722, Republic of Korea, 2Microbiology and Molecular Biology, Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Stomatology Hospital of Guangzhou Medical University, 510170, P. R. China
Bibliography Journal of Microbiology, 55(4),311-317, 2017,
DOI 10.1007/s12275-017-7052-9
Key Words Helicobacter pylori, cot, erk activation, IL-8, mapk pathway
Abstract Helicobacter pylori is a major pathogen causing various gastric diseases including gastric cancer. Infection of H. pylori induces pro-inflammatory cytokine IL-8 expression in gastric epithelial cells in the initial inflammatory process. It has been known that H. pylori can modulate Ras-Raf-Mek-Erk signal pathway for IL-8 induction. Recently, it has been shown that another signal molecule, cancer Osaka thyroid oncogene/tumor progression locus 2 (Cot/Tpl2) kinase, activates Mek and Erk and plays a role in the Erk pathway, similar to MAP3K signal molecule Raf kinase. Therefore, the objective of this study was to determine whether Cot kinase might be involved in IL-8 induction caused by H. pylori infection. AGS gastric epithelial cells were infected by H. pylori strain G27 or its isogenic mutants lacking cagA or type IV secretion system followed by treatment with Cot kinase inhibitor (KI) or siRNA specific for Cot kinase. Activation of Erk was assessed by Western blot analysis and expression of IL-8 was measured by ELISA. Treatment with Cot KI reduced both transient and sustained Erk activation. It also reduced early and late IL-8 secretion in the gastric epithelial cell line. Furthermore, siRNA knockdown of Cot inhibited early and late IL-8 secretion induced by H. pylori infection. Taken together, these results suggest that Cot kinase might play a critical role in H. pylori type IV secretion apparatus-dependent early IL-8 secretion and CagA-dependent late IL-8 secretion as an alternative signaling molecule in the Erk pathway.