Single cell analysis of the dorsal V-SVZ reveals differential quiescence of postnatal pallial and subpallial neural stem cells driven by TGFbeta/BMP-signalling

The ventricular-subventricular zone (V-SVZ) is the largest neurogenic region of the postnatal forebrain, containing neural stem cells (NSCs) that emerge from both the embryonic pallium and subpallium. Despite of this dual origin, glutamatergic neurogenesis declines rapidly after birth, while gabaergic neurogenesis persists throughout life. Here, we performed single-cell RNA-sequencing (scRNA-Seq) of the postnatal dorsal V-SVZ for unravelling the mechanisms leading to pallial lineage germinal activity silencing. We identify cell lineage-specific NSCs primed for the generation of neurons or glial cells, as well as a large population of so far uncharacterized quiescent NSCs (qNSC). Pallial qNSCs enter a state of deep quiescence, characterized by persistent TGFbeta/BMP signalling, reduced transcriptional activity and Hopx expression, whilst in contrast, subpallial qNSCs remain transcriptionally primed for activation. Induction of deep pallial quiescence is paralleled by a rapid blockade of glutamatergic neuron production and differentiation. Finally, manipulation of the TGFbeta/BMP receptor Bmpr1a demonstrate its key role in mediating these effects at early postnatal times. Together, our results highlight a central role of TGFbeta/BMP-signalling in synchronizing quiescence induction and blockade of neuronal differentiation to rapidly silence pallial germinal activity after birth.