Derived from the ectoderm, neural crest cells undergo extensive differentiation and migration to generate a remarkable range of cells. These include neurons and glia that compose the sensory, sympathetic, and parasympathetic nervous systems. In addition, neural crest cells form pigment cells, facial cartilage and bone, and connective tissues. Briefly, the neural crest can be divided into four domains; the cranial (cephalic), trunk, vagal and sacral, and cardiac neural crest. Each domain responds to specific migration and differentiation signals to generate the appropriate cells and tissues. Given the evidence supporting the central importance of the neural crest, it is often considered in addition to the ectoderm, endoderm, and mesoderm, as a fourth germ layer.
The signaling cascades that govern the migration and differentiation of neural crest cells are not completely understood. However, BMP-4 and BMP-7 are known to be important factors, as is Notch, and the spatial and temporal control of Cadherins and other adhesion molecules. Harnessing the therapeutic potential of neural crest cells is of high interest to researchers in the field of regenerative medicine.