19 - Neural Crest Cells

Abstract

This chapter describes recent advances in the understanding of neural crest cell formation and patterning in relation to stem cells, which has important implications for stem cell therapy and tissue engineering. Neural crest cells are a migratory cell population that produces a range of differentiation fates including neurons, glia, cartilage, bone, pigment cells, and connective tissue, during embryonic development. Neural crest cell patterning is achieved through a combination of cell intrinsic information acquired in the neural tube during their formation and cell extrinsic events, which influence their subsequent migration and differentiation. The major issues in stem cell biology concern the determination of “stemness” and how distinct derivatives are generated from the same stem cell population, whether by cell-intrinsic or cell-extrinsic cues. Neural crest cell derivatives generate a variety of cell types and structures along the anterior–posterior (A–P) axis of a vertebrate embryo. Gene expression studies have shown that the Hox family of transcription factors display, ordered and nested domains of expression in cranial and trunk neural crest cells as they migrate from the neural tube. The best evidence for primary roles of Hox genes in regulating the A–P identity of neural crest cells is seen in cranial regions. In an ectopic arch environment, cranial neural crest cells are unable to initiate or maintain their proper A–P patterning program based on restricted Hox expression. Stem cells are defined as clonogenic self-renewing progenitor cells that can generate one or more specialized cell types.