Vascular Endothelial Growth Factor Receptor 3 (VEGFR3) controls hippocampal neural stem cell conversion into progenitor cells

Neural stem cells (NSCs) continuously produce new neurons within the adult mammalian hippocampus. However, this process declines with age and this decline correlates with defects in cognitive function and mood. Molecular mechanisms that activate quiescent NSCs to generate progenitor cells in vivo remain poorly understood. Here we show that adult hippocampal NSCs express VEGFR3, a key regulator of vascular and neural development, and are activated by the VEGFR3 ligand VEGF-C to enter the cell cycle and convert into progenitor cells. Conditional deletion of Vegfr3 in NSCs leads to a decline in hippocampal neurogenesis. Functionally, this is associated with increased anxiety behavior and compromised NSC activation in response to VEGF-C and physical activity. These findings establish VEGFR3 expression as a hallmark of adult mouse NSCs and demonstrate a specific requirement for VEGF-C/VEGFR signaling in NSC activation. Enhancing VEGFR3 signaling by VEGF-C may improve neurogenesis and mood during aging.