Reactive oxygen species (ROS) are signaling molecules involved in many physiological processes including cell differentiation. We investigated the role of redox signaling pathways on differentiation of oligodendrocytes (OL), the myelin forming cells in the CNS.

OL cell line MO3-13, with the phenotypic characteristics of oligodendrocyte precursors cells (OPCs), exposed for 4 days to mild oxidative stress (200mM H2O2) show increased expression of OL differentiation markers P-ERK1/2 (1.5+/­0.2), P-CREB (1.7+/­0,2), Olig-2 (2.5+/­0.3) and Myelin Basic Protein (MBP, 3.9+/­0.3) and reduced levels of the negative differentiation marker a-Smooth Muscle Actin (0.55+/­0.05) relative to unstimulated cells. Confocal analysis of MBP shows accumulation of the protein in the cell processes and membrane. Cell differentiation by 100nM phorbol myristate acetate (PMA/no serum), is dependent on ROS generated by the membrane-bound superoxide generating NADPH oxidase (NOX) enzyme, since co-incubation of the cells for 4 days with differentiation stimulus and a specific NOX inhibitor, apocynin (50mM), inhibits cell differentiation. The Protein Kinase C (PKC) signaling pathway is involved in oxidative stress-induced differentiation since 2,3-butanedione 2-monoxime (100mM), a PKC inhibitor, reverted cell differentiation induced by oxidative stress or PMA/no serum. These data demonstrate that ROS generated by NOX enzyme induce OPCs differentiation through PKC signaling pathway.