Previous studies have reported that in embryonic brain, the sprouting pial capillaries penetrate the cerebral cortex and differentiate into the intracerebral vascular components. Such vascular components are commonly expressing not only CD31 but also nestin, the latter is known as a neural stem cell marker. We examined whether CD31-positive cells derived from the embryonic cerebral cortex have a potential to differentiate into neural lineage.
The localization of CD31-positive cells in the embryonic (E17) mouse brain was analyzed by immunohistochemistry. The vessel-associated nestin-positive cells co-expressed CD31. Immunoelectron microscopy confirmed that CD31 was localized not only to the endothelial cell membranes but also to the membrane of pericyte-like cells at adhering site to the endothelial cells. The CD31-positive cells sorted by MACS could produce neurosphere-like clusters, which differentiated into neural lineage.
These results indicate that CD31-positive cerebral endothelial cells and pericytes at fetal and neonatal stage have a potential to differentiate into neural cells. It is well known that the interaction of neurogenesis and angiogenesis is coordinated in postnatal brain. The present study suggests the new mechanism for regulating neurovasculogenesis of post-injured brain.