In vitro migration assays of neural stem cells.

We describe three rapid procedures for the in vitro investigation of molecular factors influencing the migration of neural precursors derived from embryonic or postnatal neural stem cells. In the first assay, factors influencing chain migration from the anterior subventricular zone of perinatal mice can be analyzed after explantation and embedding in Matrigel, a three-dimensional substrate mimicking the in vivo extracellular matrix. The second assay enables to assess soluble factors influencing radial migration away from adherent neurospheres in which embryonic stem cells have been expanded. In this example, neurospheres have been derived from the striatum primordium of embryonic mice. Finally, the directed migration of these precursor cells can be analyzed using a chemotaxis chamber assay, in which the directional movement (chemotaxis) of cells across a membrane occurs in controlled conditions. These three assays are useful tools to evaluate the importance of surface molecules and environmental factors, such as the polysialylated form of neural cell adhesion molecule (NCAM) or chemokines such as CXCL12, in the directional migration of neural precursors.