In vitro assays for neural stem cell differentiation: induction of dopaminergic phenotype.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra. Symptoms include tremors, rigidity, bradykinesia, and instability. Neural transplantation is a promising strategy for improving dopaminergic dysfunction in PD provided that the dopaminergic neurons are consistently generated from a renewable source of cells. Neural stem cells (NSCs) have the ability to self-renew, generate a large number of progeny, and differentiate into the principal nervous system cell types. As such, stem cells provide an exciting opportunity to understand the basic mechanisms involved in cell differentiation and histogenesis. These mechanisms have translational applications in tissue engineering and biomedicine in general. In vitro differentiation assays are important in cell characterization, in assaying for novel instructive molecules, and in generating specific cell types. We describe differentiation techniques to test NSCs for multipotency and to induce the dopaminergic phenotype in neural stem cell progeny by coculturing them with astrocytes and treating them with conditioned media and basic fibroblastic growth factor.