Background and aim: Dual immunoglobulin domain-containing adhesion molecule (DICAM), a novel cell adhesion moleucule, has been recently identified and known for the involvement in cell-cell adhesion through a heterophilic interaction with integrin. The aim of this study was to determine the function of DICAM in dextran sulfate sodium (DSS)-induced colitis model of mice.
Method: DSS (4%) was orally administered for 5 days to induce colitis. The disease activity index (DAI) and bowel length were determined.
Results: DSS administered mice showed increase in DAI scores and decrease in bowel length at day 5 while these manifestations recovered at day 14. Severity of inflammation which had peaked at day 5 became to attenuate at day 14. Expression of DICAM, determined in colon using Western blot as well as immunohistochemical analysis, increased at day 5, but recovered to control level after DSS withdrawal, which corresponded to the severity of inflammation. Possible involvement of DICAM was then evaluated in vitro using Caco-2 colonic epithelial cells. Caco-2 cell was differentiated and this differentiation was validated by measuring the expression profiles of genes for sucrose isomaltase, alkaline phosphatase, and oligopeptide transporter. We found that the expression of DICAM was enhanced according to the time-course of differentiation. Expression of DICAM in differentiated Caco-2 cells was further accentuated by TNF-α and IFN-γ treatment, which implicates the possible involvement of DICAM in intestinal inflammation.
Conclusion: Our study demonstrated that DICAM expression is correlated with inflammation of colon epithelial cells. Further study is needed to investigate the main function of DICAM in the pathogenesis of colitis.