Abstract
Intestinal epithelial cell (IEC) is the first line of mucosal surface that faces the challenge of exogenous pathogens. IEC play a pivotal role in host defense by sensing microbial infection, resulting in the production of proinflammatory cytokines that affect leukocyte functions. Glucosamine, a naturally occurring amino monosaccharide, has been shown to inhibit neutrophil activation. However, it has not been examined whether glucosamine affects the IEC functions. In this study to investigate the effect of glucosamine on IEC, we used a human colon cancer cell line (HT-29) and stimulated with LPS and IL-1β to induce IL-8 production. Glucosamine significantly inhibited the LPS- and IL-1β-induced IL-8 production from HT-29. Further, the effect of glucosamine on LPS- and IL-1β-binding to the cells was examined by using biotinyled-LPS and 125I-labeled IL-1β; however, glucosamine did not essentially affect the LPS- and IL-1β-binding to HT-29. Furthermore, we investigated the effect of glucosamine on the phosphorylation of p38 MAPK. Glucosamine inhibited IL-1β-induced phosphorylation of p38 MAPK. These observations indicate that glucosamine inhibits IL-8 production from HT-29 cells by affecting the p38 MAPK-mediating signaling pathway, downstream of the ligand binding to the receptors.
