Functions of chondroitin/dermatan sulfate containing GalNAc4,6-disulfate.

Chondroitin sulfate (CS) and dermatan sulfate (DS) containing GalNAc4,6-disulfate (GalNAc4S6S) were initially discovered in marine animals. Following the discovery, these glycosaminoglycans have been found in various animals including human. In the biosynthesis of CS/DS containing GalNAc4S6S, 3 groups of sulfotransferases are involved; chondroitin 4-sulfotransferases (C4STs), dermatan 4-sulfotransferase-1 (D4ST-1), and GalNAc 4-sulfate 6-O-sulfotransferase (GalNAc4S-6ST). GalNAc4S-6ST and its products have been shown to play important roles in the abnormal pathological conditions such as central nervous system injury, cancer development, abnormal tissue fibrosis, development of osteoporosis, and infection with viruses or nematodes. CS/DS containing GalNAc4S6S has been shown to increase with the functional differentiation of mast cells, macrophages, and neutrophils. Genetic approaches using knockout or knockdown of GalNAc4S-6ST, blocking of the epitopes containing GalNAc4S6S by specific antibodies and chemical technology that enabled the synthesis of oligosaccharides with defined sulfation patterns, have been applied successfully to these investigations. These studies contributed significantly to the basic understanding of the functional roles of CS/DS containing GalNAc4S6S in various abnormal conditions and appear to provide promising clues to the development of possible measures to treat them.