Glycosylation and annexin II cell surface translocation mediate airway epithelial wound repair

Abstract

Glycosylation of cell surface proteins can regulate multiple cellular functions. We hypothesized that glycosylation and expression of glycoproteins after epithelial injury is important in mediating repair. We report the use of an in vitro culture model of human airway epithelial cells (1HAEo(-)) to identify mediators of epithelial repair. We characterized carbohydrate moieties associated with repair by their interaction with the lectin from Cicer arietinum, chickpea agglutinin (CPA). Using CPA, we identified changes in cell surface glycosylation during wound repair. Following mechanical wounding of confluent monolayers of 1HAEo(-) cells, CPA staining increases on the cell surface of groups of cells in proximity to the wound edge. Blocking the CPA carbohydrate ligand inhibited wound repair highlighting the role of the CPA carbohydrate ligand in epithelial repair. Annexin II (AII), a calcium-dependent, membrane-associated protein, was identified as a protein associated with the CPA ligand. By membrane protein biotinylation and immunodetection, we have shown that following mechanical wounding, the presentation of AII on the cell surface increases coordinate with repair. Cell surface AII accumulates in proximity to the wound. Furthermore, translocation of AII to the cell surface is N-glycosylation dependent. We are the first to demonstrate that following injury, N-glycosylation events and AII presentation on the cell surface of airway epithelial cells are important mediators in repair.