Quarta-feira - Dia - 23/05 às 11 am

LOCAL: INSTITUTO DO CÉREBRO

The adult brain harbours cells with cardinal properties of neural stem cells, namely self-renewal and multipotency. Under physiological conditions, these cells are restricted to two germinative niches located in the lateral wall of the lateral ventricles and dentate gyrus. After stab wound injury, however, cortical astrocytes resume proliferation, express the transcription factor Olig2, associated with self-renewal, and give rise to neuronal cells, whereas astrocytes isolated from uninjured cortices fail to adopt such properties. These observations suggest that some signalling is taking place after SW and turning astrocytes into self renewing, multipotent neural stem cells. Yet, the factors that are upregulated upon cortical injury and confer multipotency to this astroglial cells are not known. Here we developed a bioassay to examine whether diffusible or membrane bound molecules could elicit those effects. After this assay revealed a key role for diffusible factors, a candidate approach identified Sonic Hedgehog (Shh) as both necessary and sufficient to render cortical astroglia with self renewal and multipotent competence.