Characterization of chondroitin sulfate and dermatan sulfate proteoglycans of extracellular matrices of human umbilical cord blood vessels and Wharton's jelly

The chondroitin sulfate/dermatan sulfate proteoglycans (CS/DSPGs) of the human umbilical cord vein, arteries and Wharton's jelly matrices were characterized and localized by immunohistochemical analysis. The CS/DSPGs were found to be decorins and biglycans with 43-48 kDa core proteins and are distributed throughout the umbilical cord. A truncated form of decorin having only the ∼14 kDa NH ₂-terminal portion of the core protein was found exclusively in the vein. The proteoglycans, regardless of their locations, have two types of CS/DS chains, one with ∼90% CS and ∼10% DS and the other with ∼65% CS and ∼35% DS. The glycosaminoglycan (GAG) chains of the truncated decorin consist of ∼53% CS and ∼47% DS. Both decorin and biglycan including the truncated form of decorin could efficiently bind collagen I and fibronectin. The decorin and biglycan with ∼10% DS and ∼90% CS were loosely bound in the extracellular matrices, whereas those with ∼35% DS bound strongly. Together, these data demonstrate that, the GAG chains with 35-47% DS but not those with 10% DS, interact strongly with the matrix. Our data also show that the GAG chain composition is a significant factor in binding of the decorin and biglycan to matrix proteins. The expression of decorin and biglycan with distinctively different CS/DS proportions implies specific biological functions for these PGs in the umbilical cord. The occurrence of the truncated form of decorin exclusively in the umbilical vein suggests a specific functional role.