Il differenziamento degli interneuroni nel cervello basale è controllato attraverso modalità intrinseche (ad opera dei geni DLX) e ambientali

Interneuron differentiation in the basal telencephalon is controlled by genetic (by Dlx genes) and environmental factors. Cell fate determination involves a cooperation of multiple genetic (cell-autonomous) and environmental/local (non cell-autonomous) factors. In the embryonic basal forebrain and in restricted (neurogenic) regions of the adult brain the precursors of olfactory and cortical interneurons originate near the ventricle, migrate and then differentiate into various subtypes (including GABA+, CR+, TH+ ..). Elucidating these processes is of great importance, for the implications on the use of (endogenous or grafted) neural stem cells (NS) in cell-replacement therapies. Dlx genes mark migrating neural progenitors, fated to become GABA+ interneurons in the olfactory bulb (OB) and in the cortex, and have been directly implicated in the acquisition of the GABAergic phenotype. In the neonatal OB Dlx5 is a good marker for the interneuron cell lineage, including CR+, TH+ and GABA+ cells. In Dlx5 mutant mice the cell layers are disorganized and differentiated interneurons are reduced in number. To examine the cell-autonomous control of Dlx5 on interneuron differentiation we are using mouse NS: these cells proliferate as monolayer cultures, do not require a “niche” (or a neurosphere), remain totipotent and capable to differentiate in vitro into multiple neural types, including GABA+ neurons. We expose NS cells to differentiation stimuli and quantitatively examine expression of Dlx genes, proneural genes and GAD. Dlx expression follows a temporal sequence that recapitulates neurogenesis in the basal brain: Dlx2 is expressed in both precommitted and differentiated cells while Dlx5 is upregulated in differentiated (GABA+) cells. These results provide a molecular validation for the use of NS as a model of basal neurogenesis, and indicate that Dlx5 is linked to GABA+ differentiation. We are going to define the Dlx pathway in NS cells by interfering with specific components and examine their molecular and differentiation properties.