Olfactory ensheathing cells promote migration of Schwann cells by secreted nerve growth factor.

Transplantation of Schwann cells (SCs) and olfactory ensheathing cells (OECs) have emerged as very promising therapies for spinal cord repair. The important features of interaction between SCs and OECs are beginning to be appreciated, although the underlying mechanism remains unclear. In the present study, we tested the effects of OECs on SCs migration using a range of in vitro migration assays. We found that SCs migrated abundantly upon OECs monolayer, and the migration-promoting effects were identified to be due to the secreted diffusible factors in OEC-derived conditioned medium (OEC-CM). Furthermore, neutralizing nerve growth factor (NGF) in OEC-CM with NGF antibody could block this effect. Moreover, we found that NGF promotes SCs migration even on astrocyte monolayer. Taken together, these findings provide the first evidence that OECs can promote SCs migration in astrocytic environment by secreted NGF.