Stimulation of proteoglycan release from cultured vascular endothelial cell layers by sodium spirulan

Our previous study suggested that sodium spirulan (Na-SP) stimulated the release of proteoglycans from cultured vascular endothelial cell layers. In the present study, we characterized the stimulatory effect of Na-SP on endothelial proteoglycan release from the viewpoint of the Na-SP structure. The following results were obtained: Na-SP is a potent stimulator of endothelial proteoglycan release. The stimulatory effect of Na-SP disappears with desulfation or removal of sodium ion. Depolymerized Na-SPs (M_r ∼14700 or greater) also exhibits stimulatory effects as does Na-SP (M_r ∼220000). The stimulation occurs more potently in endothelial cells than in vascular smooth muscle cells. Therefore it is suggested that the stimulatory effect of Na-SP on proteoglycan release requires both the sulfate group and sodium ion, and the effect is achieved by an active structure in the molecule which interacts particularly with the endothelial cell extracellular matrix.