Role of carbohydrates in repair of human respiratory epithelium using an in vitro model

Background The epithelial layer in the conducting airway provides a primary protective barrier. Repair of this barrier normally occurs rapidly after damage, but is compromised in diseases such as asthma. Objective We have developed a human in vitro model system to test our hypothesis that cell surface glycoconjugate-based interactions are required for the normal repair of damaged epithelium. Methods Lectins having narrow carbohydrate specificities were used to identify and block specific carbohydrate moieties on human airway-derived epithelial cells in culture. Results The lectin wheat germ agglutinin bound to N-acetyl glucosamine and inhibited the repair of epithelial damage while having little effect on cell viability. In contrast, other N-acetyl glucosamine binding lectins had no effect even when bound to the cell surface. The involvement of glycoconjugates was confirmed by pre-incubating the lectin with its specific sugar, preventing the inhibition of repair. Conclusion These results indicate that lectin-binding sites are involved in epithelial repair and may be important in the repetitive cycles of injury and repair seen in asthma. This model system provides an insight into the role of glycoconjugates and will help to determine the function of specific carbohydrate groups in epithelial repair. These may present a target for therapeutic intervention in respiratory and other diseases.