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World J Gastroenterol. Jun 28, 2006; 12(24): 3895-3900
Published online Jun 28, 2006. doi: 10.3748/wjg.v12.i24.3895
Interaction between enteric epithelial cells and Peyer’s patch lymphocytes in response to Shigella lipopolysaccharide: Effect on nitric oxide and IL-6 release
Jie Chen, Chuen-Pei Ng, Dewi K Rowlands, Peng-Hui Xu, Jie-Ying Gao, Yiu-Wa Chung, Hsiao-Chang Chan
Jie Chen, Chuen-Pei Ng, Dewi K Rowlands, Yiu-Wa Chung, Hsiao-Chang Chan, Epithelial Cell Biology Research Center, Department of Physiology, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, China
Peng-Hui Xu, Jie-Ying Gao, Department of Immunology, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing 100071, China
Jie Chen, Department of Biology, Faculty of Medicine, Shanxi Medical University, Taiyuan 030001, Shanxi Province, China
Author contributions: All authors contributed equally to the work.
Supported by Strategic Program of Chinese University of Hong Kong, and Distinguished Young Investigator Fund of the National Natural Science Foundation of China, No. 30029002
Correspondence to: Dr. Hsiao-Chang Chan, Department of Physiology, Chinese University of Hong Kong, Shatin, NT, Hong Kong, China. hsiaocchan@cuhk.edu.hk
Telephone: +852-26096839 Fax: +852-26035022
Received: August 10, 2004
Revised: September 20, 2004
Accepted: September 30, 2004
Published online: June 28, 2006
Abstract

AIM: To investigate the effect of interaction between enteric epithelial cells and lymphocytes of Peyer’s patch on the release of nitric oxide (NO) and IL-6 in response to Shigella lipopolysaccharide (LPS).

METHODS: Human colonic epithelial cells (Caco-2) were mixed cocultured with lymphocytes of Peyer’s patch from wild-type (C57 mice) and inducible NO synthase knockout mice, and challenged with Shigella F2a-12 LPS. Release of NO and mIL-6 was measured by Griess colorimetric assay and enzyme-linked immunosorbent assay (ELISA), respectively.

RESULTS: In the absence of LPS challenge, NO was detected in the culture medium of Caco-2 epithelial cells but not in lymphocytes of Peyer’s patch, and the NO release was further up-regulated in both cocultures with lymphocytes from either the wild-type or iNOS knockout mice, with a significantly higher level observed in the coculture with iNOS knockout lymphocytes. After Shigella F2a-12 LPS challenge for 24-h, NO production was significantly increased in both Caco-2 alone and the coculture with lymphocytes of Peyer’s patch from the wild-type mice but not from iNOS knockout mice. LPS was found to stimulate the release of mIL-6 from lymphocytes, which was suppressed by coculture with Caco-2 epithelial cells. The LPS-induced mIL-6 production in lymphocytes from iNOS knockout mice was significantly greater than that from the wild-type mice.

CONCLUSION: Lymphocytes of Peyer’s patch maintain a constitutive basal level of NO production from the enteric epithelial cell Caco-2. LPS-induced mIL-6 release from lymphocytes of Peyer’s patch is suppressed by the cocultured epithelial cells. While no changes are detectable in NO production in lymphocytes from both wild-type and iNOS knockout mice before and after LPS challenge, NO from lymphocytes appears to play an inhibitory role in epithelial NO release and their own mIL-6 release in response to LPS.

Keywords: Shigella F2a-12 LPS; Colon epithelial cells (Caco-2); Peyer’s patch lymphocyte; Coculture; Nitric oxide; Interleukin-6