Leptomeningeal-Derived Doublecortin-Expressing Cells in Poststroke Brain

Increasing evidence indicates that neural stem/progenitor cells (NSPCs) reside in many regions of the central nervous system (CNS), including the subventricular zone (SVZ) of the lateral ventricle, subgranular zone of the hippocampal dentate gyrus, cortex, striatum, and spinal cord. Using a murine model of cortical infarction, we recently demonstrated that the leptomeninges (pia mater), which cover the entire cortex, also exhibit NSPC activity in response to ischemia. Pial-ischemia-induced NSPCs expressed NSPC markers such as nestin, formed neurosphere-like cell clusters with self-renewal activity, and differentiated into neurons, astrocytes, and oligodendrocytes, although they were not identical to previously reported NSPCs, such as SVZ astrocytes, ependymal cells, oligodendrocyte precursor cells, and reactive astrocytes. In this study, we showed that leptomeningeal cells in the poststroke brain express the immature neuronal marker doublecortin as well as nestin. We also showed that these cells can migrate into the poststroke cortex. Thus, the leptomeninges may participate in CNS repair in response to brain injury.