Figure 3. An illustrative model on how changes in HA regulate NSPCs in normal state and in response to injury. (1) CNS insults activate NSPCs in the subventricular zone (SVZ); (2) HA in the niche is degraded due to increased hyaluronidase activity of NSPCs and other cell types and therefore (3) NSPCs proliferate, migrate toward the lesion and differentiate to OPCs. (4) However, their maturation is inhibited if they encounter HMW HA-rich chronic lesions. Reproduced with permission from ref. 26.