CXC and CC Chemokine Expression by Intestinal Epithelial Cells in Response to Clostridium difficile Toxin A

Jung, Hyun Chae; Kim, Jung Mogg; Kim, Joo Sung; Song, In Sung; Kim, Chung Yong

Abstract

BACKGROUND/AIMS: Intestinal epithelial cells can play a role in signaling the influx of inflammatory cells. We investigated the regulated expression of CXC and CC chemokines by intestinal epithelial cells in response to Clostridium difficile (C. difficile) infection.
METHODS
Quantitative RT-PCR and ELISA were used to assess the expression of CXC and CC chemokines in human intestinal epithelial cells after stimulation with C. digcile toxin A. To determine the polarity of chemokine secretion, chemokine production was measured from culture supernatants of Caco-2 cells which were cultured in transwell chambers.
RESULTS
The expression of the CXC chemokine, GRO-alpha and IL-8, increased in the first hr after stimulation. In contrast, the expression of epithelial neutrophil activating protein (ENA)-78 mRNA was delayed for 18 hr. The CC chemokine monocyte chemotactic protein (MCP)-1 mRNA, was expressed in 3 hr after stimulation. Upregulated mRNA expression of chemokines was paralleled by the increase of protein levels. After stimulating Caco-2 cells with toxin A, CXC and CC chemokines were released predominantly into the basolateral compartment. Moreover, the addition of IFN-y and tumor necrosis factor (TNF)-a to toxin A-stimulated Caco-2 cells showed an increased basolateral release of CC chemokine, MCP-1.
CONCLUSIONS
These results suggest that the expression of CXC and CC chemokine in the epithelial cells stimulated with C. difficile toxin A may be an important factor in the mucosal inflammatory response.