EXPRESSION OF SMALL EXTRACELLULAR CHONDROITIN DERMATAN SULFATE PROTEOGLYCANS IS DIFFERENTIALLY REGULATED IN HUMAN ENDOTHELIAL-CELLS/

We have examined the expression of the small extracellular chondroitin /dermatan sulfate proteoglycans (CS/DS PGs), biglycan, decorin, and PG -100, which is the proteoglycan form of colony stimulating factor-1, i n the human endothelial cell line EA.hy 926. We have also examined whe ther modulation of the phenotype of EA.hy 926 cells by tumor necrosis factor-alpha (TNF-alpha) is associated with specific changes in the sy nthesis of these PGs. We demonstrate that EA.hy 926 cells, when they f orm monolayer cultures typical of macrovascular endothelial cells, exp ress and synthesize detectable amounts of biglycan and PG-100, but not decorin. On SDS-polyacrylamide gel electrophoresis both PGs behave li ke proteins of the relative molecular weight of similar to 250,000, TN F-alpha that changed the morphology of the cells from a polygonal shap e into a spindle shape and that also stimulated the detachment of the cells from culture dish, markedly decreased the net synthesis of bigly can, whereas the net synthesis of PG-100 was increased. These changes were parallel with those observed at the mRNA level of the correspondi ng PGs. The proportions of the different sulfated CS/DS disaccharide u nits of PGs were not affected by TNF-alpha. Several other growth facto rs/cytokines, such as interferon-gamma, fibroblast growth factors-2 (F GF-2) and -7 (FGF-7), interleukin-1 beta, and transforming growth fact or-beta, unlike TNF-alpha, modulated neither the morphology nor the bi glycan expression of EA.hy 926 cells under the conditions used in the experiments. However, PG-100 expression was increased also in response to PGF-2 and -7 and transforming growth factor-beta. None of the abov e cytokines, including TNF-alpha, was able to induce decorin expressio n in the cells. Our results indicate that the regulatory elements cont rolling the expression of the small extracellular CS/DS PGs in human e ndothelial cells are different.