CREB signalling regulates early survival, neuronal gene expression and morphological development in adult subventricular zone neurogenesis

Neural stem cells in the subventricular zone (SVZ) of the lateral ventricles give rise to new interneurons of the olfactory bulb (OB) throughout life. SVZ/OB neurogenesis is influenced by olfactory network activity, which modulates the survival of new neurons during their integration into the OB network. Previous work suggested that such activity-dependent survival is regulated via the CREB signalling pathway. Curiously, CREB signalling is already active during the early developmental stages of adult SVZ/OB neurogenesis. To investigate the role of cell autonomous CREB signalling during early stages of adult SVZ/OB neurogenesis, we ablated CREB-pathway activity in the SVZ/OB neurogenic lineage using a retroviral strategy. Surprisingly, loss of CREB signalling resulted in increased cell death and loss of expression of the neurogenic transcription factor Pax 6, and of a subset of neuronal proteins in migrating neurons of the RMS. Moreover, post-migratory neurons in the OB displayed impaired dendritic development. These results demonstrate an essential role for CREB signalling in maturation of newborn neurons in the OB and uncover a novel role for CREB signalling in the survival and maintenance of neuronal gene expression during the early stages of SVZ/OB neurogenesis.