Stimulation of Proteoglycan Release from Cultured Vascular Endothelial Cell Layers by Sodium Spirulan

Abstract

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.

Proteoglycans Released from Cultured Bovine Aortic Endothelial Cell Layers by Sodium Spirulan Are Both Perlecan and Biglycan

“…18) Although not only Na-SP but also other particular polysaccharides such as heparin, dextran sulfate and hyaluronan can stimulate endothelial PG release, 19) it has been unclear whether these polysaccharides act on the release of both HSPGs and CS/DS PGs, as does Na-SP. As shown in Fig.…”

“…18) Not only Na-SP, but also heparin, dextran sulfate and hyaluronan, stimulates the release of PGs from vascular endothelial cell layers. 19) However, it was shown that the stimulation by heparin, dextran sulfate and hyaluronan occurred mainly in the HSPG release, whereas that by Na-SP did in both HSPGs and CS/DS PGs. In other words, Na-SP is a particular polysaccharide that strongly stimulates the release of CS/DS PG, specifically biglycan, from vascular endothelial cell layers.…”

“…19) However, the type(s) of endothelial PGs whose release is stimulated by Na-SP has not been identified yet. In the present study, we suggest that Na-SP-releasable PGs in vascular endothelial cells are both perlecan and biglycan with the intact structure, although the core proteins may be partially degraded.…”

“…17) It was shown that Na-SP stimulates the endothelial PG release as does heparin 18) ; the stimulatory effect requires both the sulfate group and a sodium ion. 19) However, the type(s) of endothelial PGs whose release is stimulated by Na-SP has not been identified yet. In the present study, we suggest that Na-SP-releasable PGs in vascular endothelial cells are both perlecan and biglycan with the intact structure, although the core proteins may be partially degraded.…”

Inhibition of Cultured Bovine Aortic Smooth Muscle Cell Proliferation by Colominic Acid

“…11) In vascular endothelial cells, Na-SP elevates the fibrinolytic activity of vascular endothelial cells through inhibition of the secretion of plasminogen activator inhibitor type 1. 12) In addition, Na-SP promotes the secretion of anticoagulant proteoglycans 13) such as perlecan and biglycan, 14) as well as exhibiting an antithrombin activity through activation of heparin cofactor II. 15,16) We hypothesized that CA or SCA may inhibits the proliferation of vascular smooth muscle cell proliferation, as does natural or semi-synthetic polysaccharides, including Na-SP, heparin, 17) pentosan polysulfate 18) and fucoidan.…”