Regulation of subventricular zone-derived cells migration in the adult brain.

The subventricular zone of the lateral ventricles (SVZ) is the largest source of neural stem cells (NSCs) in the adult mammalian brain. Newly generated neuroblasts from the SVZ form cellular chains that migrate through the rostral migratory stream (RMS) into the olfactory bulb (OB), where they become mature neurons. Migration through the RMS is a highly regulated process of intrinsic and extrinsic factors, orchestrated to achieve direction and integration of neuroblasts into OB circuitry. These factors include internal cytoskeletal and volume regulators, extracellular matrix proteins, and chemoattractant and chemorepellent proteins. All these molecules direct the cells away from the SVZ, through the RMS, and into the OB guaranteeing their correct integration. Following brain injury, some neuroblasts escape the RMS and migrate into the lesion site to participate in regeneration, a phenomenon that is also observed with brain tumors. This review focuses on factors that regulate the migration of SVZ precursor cells in the healthy and pathologic brain. A better understanding of the factors that control the movement of newly generated cells may be crucial for improving the use of NSC-replacement therapy for specific neurological diseases.