DOWN-REGULATION OF E-CADHERIN IN THE REPARATIVE EPITHELIUM OF THE HUMAN GASTROINTESTINAL-TRACT

E-cadherin, an epithelial adhesion molecule, is critical for the maint enance of cell polarity and differentiation. We studied the distributi on of E-cadherin in normal gut and in enteric ulceration to test the h ypothesis that the motility of regenerative epithelium over ulcers is associated with a decrease in E-cadherin expression. sections of norma l stomach, small intestine, and colon were examined for E-cadherin dis tribution using the antibody HECD-1 and compared with the pattern seen in peptic ulceration and Crohn's disease, A subset was examined by in situ hybridization using S-35 radiolabeled E-cadherin riboprobes. A w ounding system employing the HT-29 cell line was used as an in vitro m odel of early healing. In the normal gut uniform strong basolateral st aining was seen, Areas of ulceration showed a patchy reduction in memb rane localized E-cadherin in regenerating epithelium, even though E-ca dherin mRNA was demonstrable in this population. In wounded confluent HT29 layers, migrating cells also showed reduced E-cadherin immunostai ning. These data support the notion that the motility of restitutive e pithelial cells may relate to altered patterns of E-cadherin and that this may play an important rob in the reconstitution of epithelial int egrity after mucosal injury.