Airway epithelial wound repair: role of carbohydrate sialyl Lewisx

Abstract

Epithelial repair is a complex cellular and molecular process, the details of which are still not clearly understood. Plasma membrane glycoconjugates can modulate cell function by altering the function of protein and lipids. Sialyl Lewisx(sLex), a fucose-containing tetrasaccharide, decorates membrane-bound and secreted proteins and mediates cell-cell interaction. In the present study we investigated the role of sLexin airway epithelial repair. Using immunohistochemistry, we showed an increased expression of sLexin areas of damaged bronchial epithelium compared with intact regions. Confluent monolayers of airway epithelial cells were mechanically wounded and allowed to close. Wounded monolayers were photographed for wound closure kinetics, fixed for immunocytochemical studies, or subjected to RNA extraction. Examining the expression of different α1,3-fucosyltransferases (FucT), enzymes that mediate the final step in the synthesis of sLex, we found that FucT-IV was the common gene expressed in all cell lines and primary airway epithelial cells. We demonstrated an increased expression of sLexover time after mechanical injury. Blocking of sLexwith an inhibitory antibody completely prevented epithelial repair. Our data suggest an essential functional role for sLexin epithelial repair. Further studies are necessary to explore the exact mechanism for sLexin mediating cell-cell interaction in bronchial epithelial cells to facilitate epithelial migration and repair.