Terminal glycosylation of cystic fibrosis airway epithelial cells

Cystic fibrosis (CF) has a characteristic glycosylation phenotype usually expressed as a decreased ratio of sialic acid to fucose. The glycosylation phenotype was found in CF/T1 airway epithelial cells (Delta F508/Delta F508). When these cells were transfected and were expressing high amounts of wtCFTR, as detected by Western blot analysis and in situ hybridization, the cell membrane glycoconjugates had an increased sialic acid content and decreased fucosyl residues in alpha1,3/4 linkage to antennary N-acetyl glucosamine (Fuc alpha1,3/4GlcNAc). After the expression of wtCFTR decreased, the amount of sialic acid and Fuc alpha1,3/4GlcNAc returned to levels shown by the parent CF cells. Sialic acid was measured by chemical analysis and Fuc alpha1,3/4GlcNAc was detected with a specific alpha1,3/4 fucosidase. CF and non-CF airway cells in primary culture also had a similar reciprocal relationship between fucosylation and sialylation. It is possible that the glycosylation phenotype is involved in the pathogenesis of CF lung disease by facilitating bacterial colonization and leukocyte recruitment.