Ricerc@Sapienza

In the adult mammalian brain, production of new neurons persists in two neural stem/progenitor cell (NSPC) niches that are located in the subventricular zone (SVZ) of the lateral ventricles and in the subgranular zone of the hippocampus, respectively. Adult neurogenesis decreases with ageing, and this may significantly contribute to age-associated decline in brain function and to the increased frequency of neurological conditions in elderly patients. Despite the potential importance of these findings for human health, the underlying molecular causes of the decline in neurogenesis upon ageing are still unknown. To gain insight into the intrinsic molecular changes taking place in NSPCs during ageing, we recently performed genome-wide analyses of the transcriptional profiles of NSPCs derived from the SVZ of adult (3 months old) and aged (18 months old) mice. This analysis led to the identification of a few hundred loci showing transcriptional changes between adult and aged NSPCs. Among them, we have focused on Dbx2, a homeobox gene significantly upregulated in aged NSPCs in comparison with adult NSPCs. We found that overexpression of Dbx2 in adult NSPCs in vitro recapitulates some of the phenotypic changes associated with NSPC ageing, such as decreased NSPC ability to grow in culture and altered expression of genes implicated in NSPC self-renewal and differentiation. The goal of the proposed project is to study the effects of the loss-of-function of this gene in aged NSPCs and, in particular, to address whether Dbx2 inactivation can rescue the decreased growth capacity and the altered transcriptional profiles of aged NSPCs. Dbx2 function will be knocked down in aged NSPCs in vitro by transfecting them with plasmids expressing short-hairpin RNAs. The effects of this manipulation will be characterised through a variety of technical approaches including cell proliferation and cell viability assays and molecular markers analyses by real-time PCR and immunocytochemistry.