RESUMO
GSK-3ß is a key molecule in several signalling pathways, including the Wnt/ß-catenin signalling pathway. There is increasing evidence suggesting Wnt/ß-catenin signalling is involved in the neural differentiation of embryonic, somatic and neural stem cells. However, a large body of evidence indicates that this pathway maintains stem cells in a proliferative state. To address this controversy, we have investigated whether the Wnt/ß-catenin pathway is present and involved in the neural differentiation of newly introduced USSCs (unrestricted somatic stem cells). Our results indicate that the components of Wnt/ß-catenin signalling are present in undifferentiated USSCs. We also show that the treatment of neurally induced USSCs with BIO (6-bromoindirubin-3'-oxime), a specific GSK-3ß inhibitor and Wnt activator, for 5 and 10 days results in increased expression of a general neuronal marker (ß-tubulin III). Moreover, the expression of pGSK-3ß and stabilized ß-catenin increased by BIO in neurally induced USSCs, indicates that the Wnt pathway is activated and functional in these cells. Thus, inhibition of GSK-3ß in USSCs enhances their neural differentiation, which suggests a positive role of the Wnt/ß-catenin signalling pathway towards neural fate.