Characterization of human fibronectin glycopeptides from cystic fibrosis and control skin fibroblasts

Abstract

Fibronectins isolated from different species and tissue sources are glycosylated differently. We report here a characterization of the glycopeptides of fibronectin isolated from the culture medium of skin fibroblasts from patients with cystic fibrosis together with age-, race-, and sex-matched control subjects. The characterization of this fibronectin is of special interest because it is derived from: ( 1) a non-fetal, cellular source; ( 2) eight different individuals; and ( 3) cystic fibrosis and control individuals. The fibronectin glycopeptides were purified by gel-permeation chromatography and Con A-Sepharose and were analyzed by anion-exchange chromatography and affinity columns of immobilized 5-hydroxytryptamine and lectins. One half of the glycopeptides of skin fibroblast fibronectin were shown to contain biantennary oligosaccharides which were core-fucosylated and partially sialylated. Although the remaining half was a complex mixture of glycopeptides, there was remarkably little inter-individual variation. No difference between cystic fibrosis and control subjects was discernible by the techniques employed here. Unlike the biantennary glycopeptides of human plasma fibronectin, those from skin fibroblast fibronectin were core-fucosylated and less highly sialylated. However, compared to human cellular fibronectin glycopeptides from fetal sources, those from skin fibroblast fibronectin were both more highly fucosylated and sialylated.