Abstract: Myelination of Schwann cells in the peripheral nervous system is an intricate process involving myelin protein trafcking. Recently, the role and mechanism of the endosomal/lysosomal system in myelin formation were emphasized. Our previous results demonstrated that a small GTPase Rab27a regulates lysosomal exocytosis and myelin protein trafcking in Schwann cells. In this present study, we established a dorsal root ganglion (DRG) neuron and Schwann cell co-culture model to identify the signals associated with Rab27a during myelination. First, Slp2-a, as the Rab27a effector, was endogenously expressed in Schwann cells. Second, Rab27a expression signifcantly increased during Schwann cell myelination. Finally, Rab27a and Slp2-a silencing in Schwann cells not only reduced myelin protein expression, but also impaired formation of myelin-like membranes in DRG neuron and Schwann cell co-cultures. Our fndings suggest that the Rab27a/ Slp2-a complex affects Schwann cell myelination in vitro.

Key words: nerve regeneration, Schwann cells, dorsal root ganglion neurons, co-culture, myelin proteins, myelination, Rab27 effectors, Rab27a, Slp2-a, neural regeneration