TUMOR-NECROSIS-FACTOR ALPHA-INDUCED ALTERATION OF GLYCOSAMINOGLYCANS IN CULTURED VASCULAR SMOOTH-MUSCLE CELLS

We studied alteration of glycosaminoglycans (GAGs) induced by recombinant human tumor necrosis factor alpha (rhTNFalpha) in vascular smooth-muscle cells from bovine aorta in a culture system. It was found that rhTNFalpha at 10 ng/ml and below significantly increased the incorporation of [S-35]sulfate (S-35) but conversely decreased that of [H-3]glucosamine (H-3) into GAGs in the trypsinate fraction of the cell layer after a 24-h incubation. These results suggested that rhTNFalpha reduced the formation and/or the anchorage of sugar chains in the cell layer but enhanced their sulfation in whole GAG synthesis by the cells. In results, the ratio of S-35 to H-3 in the GAGs was markedly increased. This increase occurred after 24 h and longer when the cells were treated with 1.0 ng/ml rhTNFalpha. The TNFalpha-induced alteration of the incorporation of both S-35 and H-3 was completely blocked by anti-rhTNFalpha antibody. Other cytokines including recombinant human interleukin-1beta and -6, and platelet-derived growth factor failed to alter the ratio of S-35 to H-3 in the GAGs of the trypsinate fraction of the cell layer. In cultured vascular endothelial cells from bovine aorta, however, rhTNFalpha at 1.0 ng/ml significantly decreased the incorporation of both S-35 and H-3 into GAGs of both the trypsinate fraction and the medium; the ratio of S-35 to H-3 was not changed. Characterization of GAGs in vascular smooth muscle cell trypsinate fraction revealed that rhTNFalpha at 10 ng/ml induced (i) no change of the incorporation of 3H in the hyaluronate fraction, (ii) a marked increase in the incorporation of S-35 and no change of that of H-3 in chondroitin sulfates (A plus C) fraction, (iii) a significant decrease in the incorporation of both S-35 and H-3 in the heparan sulfate fraction, and (iv) no change of the incorporation of S-35 and a marked decrease in that of H-3 in the dermatan sulfate fraction. In the medium, rhTNFalpha also induced various changes of GAGs. It was therefore concluded that TNFalpha may have a capacity of inducing a qualitative change of vascular smooth-muscle cell GAGs, which may be involved in the vascular pathology such as atherosclerosis.