RECEPTORS IN THE PSEUDOMONAS-AERUGINOSA ADHERENCE TO INJURED AND REPAIRING AIRWAY EPITHELIUM

In the normal respiratory tract, the airway epithelial surface is prot ected from pathogenic bacterial colonization by the mucociliary cleara nce. The mucins present in the gel mucus layer exhibit a high diversit y of carbohydrate receptors that allow specific bacterial recognition followed by bacterial and mucus elimination. As soon as the mucociliar y clearance mechanism is impaired, the bacterial attachment to mucins in association with mucus stasis represent critical pathways for bacte rial colonization of the airway epithelium. Several sources of injury may damage the epithelial integrity and induce partial or complete epi thelial shedding, exposing cellular receptors and unmasked extracellul ar matrix (ECM) components that can be recognized by bacterial adhesin s. Laminin and type I and IV collagens represent sites of Pseudomonas aeruginosa attachment to the ECM components. During airway epithelium repair after injury, particularly in cystic fibrosis (CF), the repairi ng cells exhibit apical receptors such as asialylated gangliosides (as ialo GM(1)) to which P. aeruginosa adheres. The identification of the different receptors for P. aeruginosa, present either on the ECM prote ins or on the apical surface of the remodeled airway epithelium, parti cularly in repairing respiratory CF epithelial cells, is a prerequisit e to further therapeutic strategies to prevent airway colonization by P. aeruginosa.