Embryonic stem cells (ESCs) can be induced to differentiate into nerve cells, endowing them with potential applications in the treatment of neurological diseases and neural repair. In this work, we report for the first time that sulfated chitosan can promote the neural differentiation of ESCs. As a type of sulfated glycosaminoglycan analog, sulfated chitosan with well-defined sulfation sites and a controlled degree of sulfation (DS) were prepared through simple procedures and the influence of sulfated glycosaminoglycan on neural differentiation of ESCs was investigated. Compared with other sulfation sites, 6-O-sulfated chitosan showed the most optimal effects. By monitoring the expression level of neural differentiation markers using immunofluorescence staining and PCR, it was found that neural differentiation was better enhanced by increasing the DS of 6-O-sulfated chitosan. However, increasing the DS by introducing another sulfation site in addition to the 6-O site to chitosan did not promote neural differentiation as much as 6-O-sulfated chitosan, indicating that compared with DS, the sulfation site is more important. Additionally, the optimal concentration and incubation time of 6-O-sulfated chitosan were investigated. Together, our results indicate that the sulfate site and the molecular structure in a sulfated polysaccharide are very important for inducing the differentiation of ESCs. Our findings may help to highlight the role of sulfated polysaccharide in inducing the neural differentiation of ESCs.
Keywords: embryonic stem cells; heparin; neural differentiation; sulfated chitosan.