Brain pericytes, their origin and possible contribution to CNS repair

Abstract

Brain vascular pericytes (PCs) which localized in association with the endothelial cells via basal membrane play an important role in maintaining blood-brain barrier (BBB) function and may have multipotent stem cell activity to differentiate into a variety types of cells. Brain PCs are suggested to be neural crest derivatives but in another aspect they derive from the mesodermal cells through hemangioblast of the embryonal stage. Although the precise role of PCs on central nervous system (CNS) injury has not been elucidated, we have demonstrated that PCs can be reprogrammed into multipotent stem cells in response to ischemia/hypoxia, suggesting that the PCs under ischemic condition such as cerebral infarction (ischemic PCs: iPCs) contribute to CNS repair as ischemic injury-induced multipotent stem cells (iSCs) to differentiate into both neural and vascular lineage cells. Because iPC/iSCs express predominantly Nestin and Sox2, neural stem cell markers, they can play an essential role in the reparative process of neurovascular unit in CNS. Our findings may indicate a new concept that the PCs may function as latent multipotent stem cells under diseased, but not normal, condition of CNS.