Leptomeninges: a novel stem cell niche harboring ischemia-induced neural progenitors

It is well known that neural stem cells (NSCs) are present in many parts of the central nervous system (CNS), including the subventricular zone (SVZ) of the lateral ventricle, subgranular zone (SGZ) of the hippocampal dentate gyrus, cortex, and spinal cord. Using a mouse model of cortical infarction, we demonstrated for the first time that NSCs, which can differentiate into neural lineage cells, could be induced in the meninges (leptomeninges) of ischemic brain areas as well. However, such ischemia-induced NSCs (iNSCs) were not observed in the leptomeninges of non-ischemic areas. This suggests the leptomeninges, which surround the CNS, might be a novel stem cell niche harboring endogenous iNSCs following brain injury. In this review, we introduce the characterization and possible origin of leptomeningeal iNSCs based on our reports and recent findings. We also refer to the potential of leptomeningeal iNSCs for cortical neurogenesis.