Molecular Cascade Reveals Sequential Milestones Underlying Hippocampal Neural Stem Cell Development into an Adult State

Quiescent adult neural stem cells (NSCs) in the mammalian brain arise from proliferating NSCs during development. Beyond acquisition of quiescence, an adult NSC hallmark, little is known about the process, milestones and mechanisms underlying the transition of developmental NSCs to an adult NSC state. Here we performed targeted single-cell RNA-seq analysis to reveal the molecular cascade underlying NSC development in the early postnatal mouse dentate gyrus. We identified two sequential steps, first a transition to quiescence followed by further maturation, each of which involved distinct changes in metabolic gene expression. Direct metabolic analysis uncovered distinct milestones, including an autophagy burst before NSC quiescence acquisition and cellular ROS level elevation along NSC maturation. Functionally, autophagy is important for the NSC transition to quiescence during early postnatal development. Together, our study reveals a multi-step process with defined milestones underlying establishment of the adult NSC pool in the mammalian brain. Single-cell gene expression profiling of postnatal hippocampal quiescent neural stem cells (qNSCs) from P3, P7 and P14 Hopx-GFP reporter mice