Demyelination disables saltatory conduction and leads to loss of neural functions. Remyelination is mediated by oligodendrocyte precursor cells (OPCs), which are widely distributed throughout the adult CNS. A better understanding of oligodendrocyte biology, myelination, and maintenance of myelin sheaths, and the failure of remyelination in the CNS, which has been associated with the limited availability, migratory capacity and myelinating ability of endogenous OPCs, is necessary to improve remyelination strategies in a chronic inflammatory demyelinating disease such as multiple sclerosis (MS).