RTN4 and peripheral nerve injury: In particular, RhoA represents a key molecule in the axonal growth inhibitory cascade activated by several factors, e.g. CSPG, oligodendrocyte-myelin glycoprotein (OMgp), myelin-associated glycoprotein (MAG) and Nogo-66 segment from the Nogo-A molecule, which are released by astrocytes and oligodendrocytes at the lesion site upon central nervous system (CNS) or peripheral nerve injury [25].