CS/DS is enriched in the neural stem cell niche and has been shown to play important role in the differentiation of neural progenitor cells 36. Its importance has been demonstrated in progenitor cells from mice with ablations of C4ST1 (a 4-O-sulfotransferase acting on GlcA-containing sequences) and D4ST1. Down-regulation of D4ST1 resulted in the abrogation of IdoA blocks, as well as decreased neurogenesis and proliferation and a change in the expression of cell surface receptors for fibroblast growth factor (FGF)-2 and epidermal growth factor, whereas C4ST1 deficiency did not affect these processes 37. The importance of IdoA motifs was further underlined by the fact that mRNA expression of the DS epimerases was higher in differentiated neurones than in precursor stem cells 38.
