抄録
Incubation of porcine aortic endothelial cell cultures with 4-methylumbelliferyl-β-D-xyloside resulted in a reduction of 125I-antithrombin III binding to cells. When the amount of antithrombin III specifically bound was measured as a function of antithrombin III concentration, it was indicated that the maximum amount of antithrombin III binding was reduced by approximately 65% with little alteration in binding affinity. Reduction of 125I-antithrombin III bound to the surface of endothelial cells after exposure to various concentrations of xyloside occurred in parallel with the decrease in biosynthesis of radiolabeled heparan sulfate on the cell surface. Characterization of heparan sulfate molecules derived from cell surface fractions revealed that a size of the molecule was not altered by β-D-xyloside treatment, although they appeared to have slightly less net negative charge and a significantly reduced proportion of the molecule with high affinity for antithrombin III in the presence of xyloside. On the other hand, free chondroitin sulfate polysaccharide chains were markedly increased in the medium from β-D-xyloside-treated endothelial cell cultures. These results suggest that β-D-xyloside treatment of endothelial cells caused a dose-dependent decrease in production of cell surface heparan sulfate, which could serve as antithrombin III binding sites on endothelial cells.
