Proteoglycans Predominantly Synthesized by Human Brain Microvascular Endothelial Cells in Culture are Perlecan and Biglycan

Abstract

It has been suggested that the properties of vascular endothelial cells differ depending on the type of blood vessel. Proteoglycans are macromolecules that contribute to vascular properties through regulation of endothelial cell functions. In this study, we characterized proteoglycans synthesized by cultured human brain microvascular endothelial cells by biochemical techniques. The experiments indicated that the cells synthesize and secrete two types of proteoglycans: large heparan sulfate proteoglycans bearing heparan sulfate chains of approximately M_r∼68000 and chondroitin/dermatan sulfate proteoglycans bearing chondroitin/dermatan sulfate chains of approximately M_r∼48000. The heparan and chondroitin/dermatan sulfate proteoglycans were identified as perlecan and biglycan, respectively, by Western blot analysis. A part of perlecan was associated with the cell layer, while most of biglycan was secreted into the medium. These results suggest that the characteristics of proteoglycans synthesized by brain microvascular endothelial cells are similar to the characteristics of those synthesized by previously reported arterial endothelial cells. Regulation of endothelial cell functions by proteoglycans may be independent of blood vessel types.