Tumor necrosis factor α increases the expression of glycosyltransferases and sulfotransferases responsible for the biosynthesis of sialylated and/or sulfated Lewis x epitopes in the human bronchial mucosa

Abstract

There is increasing evidence that inflammation may affect glycosylation and sulfation of various glycoproteins. The present study reports the effect of tumor necrosis factor α (TNF-α), a proinflammatory cytokine, on the glycosyl- and sulfotransferases of the human bronchial mucosa responsible for the biosynthesis of Lewis x epitope and of its sialylated and/or sulfated derivatives, which are expressed in human bronchial mucins. Fragments of macroscopically normal human bronchial mucosa were exposed to TNF-α at a concentration of 20 ng/ml. TNF-α was shown to increase α1,3-fucosyltransferase activity as well as expression of the two α1,3-fucosyltransferase genes expressed in the human airway, FUT3 and FUT4. It had no influence on α1,2-fucosyltransferase activity or FUT2 expression. It also increased α2,3-sialyltransferase activity and the expression of ST3Gal-III and, more importantly, ST3Gal-IV and both N-acetylglucosamine 6-O-sulfotransferase and galactose 3-O-sulfotransferase. These results are consistent with the observation of oversialylation and increased expression sialyl-Lewis x epitopes on human airway mucins secreted by patients with severe lung infection such as those with cystic fibrosis, whose airways are colonized by Pseudomonas aeruginosa. However, other cytokines may also be involved in this process.