Unravel a neuroactive sHA sulfation pattern with neurogenesis activity by a library of defined oligosaccharides

Sulfated hyaluronic acid (sHA) is chemically synthetic mimetic of glycosaminoglycan (GAG) presenting promising biological functions. Specific sulfation pattern, termed as sulfation code plays critical roles in regulating the binding mode between GAG and proteins. As a structural analogue of chondroitin sulfate (CS), sHA bears much higher molecular weight and is nearly free of other proteoglycan contaminants. These properties make sHA a better bioscaffold to build safer and more functionalized material. However, chemical sulfonation process on naked HA polysaccharide produces random sulfation patterns which makes it difficult in disclosing the SAR. Herein, we utilized sHA and CS oligosaccharides with defined sulfation pattern to unravel the SAR between sHA and neurogenesis. We demonstrate sHA tetrasaccharide bearing 6-O-sulfation (sHA-6S) but not other sulfation patterns bind to growth factors at nanomolar range and promote the neurite outgrowth of rat E18 hippocampal neurons in vitro. Furthermore, synthetic sHA polysaccharide enriched in 6-O-sulfation also promote the hippocampal neurite outgrowth in vitro. Our work provides an effective method to disclose the bioactive sulfation pattern of sHA. Our results indicate that a specific sHA sulfation pattern could direct important physiological processes and open the way for the application of sHA-6S in neuroscience and medicine.