PLASTICITY MECHANISMS IN THE OLFACTORY BULB OF BECOMING MOTHERS

The process of new neurons production in the adult brain is called “adult neurogenesis” and is sustained by a small group of neural stem cells (NSC) which persist as developmental vestiges in tightly controlled micro-environments called “niches”. In the adult mammalian brain, the largest region retaining neurogenic ability is the Ventricular Sub-Ventricular Zone (V-SVZ), located along the lateral ventricles and giving rise to inhibitory interneurons, capable of migrating to the olfactory bulb (OB). It has recently been shown that physiological processes like pregnancy have the ability to modify V-SVZ stem cell replication in a spatial and temporal manner, altering adult neurogenesis dynamics (Chaker et al Science, 2023). Interestingly, pregnancy related neurons (PRN) integrate into layers of the OB where few neurons integrate during homeostasis, and they play a crucial role in the recognition of pup odors. Despite their relevance, these neurons disappear around weaning, but the functional relevance of such transient process are still to be elucidated. Interestingly, our transcriptomic data shows the appearance of a senescence-associated secretory phenotype (SASP) during early motherhood, and persisting until weaning. Senescence has long been related to detrimental processes such as cancer and aging, but recent studies are showing that senescence plays a key role during development for tissue remodeling and for the clearance of important transient structures. In this project, we hypothesize that pregnancy induces the re-opening of a developmental “senescence-like” program in the adult mouse brain, which allows the integration of PRN by modifying the local environment.