Generation of neural crest cells and peripheral sensory neurons from human embryonic stem cells.

Peripheral somatic sensory neurons (PSNs) are responsible for the critical function of transmitting multiple modalities of information from the outside world, including heat, touch, and pain, as well as the position of muscles required for coordinated voluntary movement to the central nervous system. Many peripheral neuropathies exist, including hereditary neurodegeneration in Familial Dysautonomia, infections of PSNs by viruses such as Varicella zoster and damage to PSNs and/or their process resulting from other disease conditions such as diabetes. Understanding of the etiology of these diseases and development of treatments is hampered by the lack of normal and healthy human PSNs for study, which are only available from abortuses or rare surgical procedures.Human embryonic stem cells (hESCs) are an ideal source of cells for generating normal PSNs for study of disease and drug development, since they can be grown virtually indefinitely in tissue culture and have the potential to form any cell type in the body. Several years ago, we generated human neurons with the molecular characteristics of PSNs from hESCs at low (less than 1%) yields (Pomp et al., Stem Cells 23:923-930, 2005). The present chapter details our most recently improved method that uses 2 rounds of PA6-induction to rapidly generate PSNs at more than 25% purity (Pomp et al., Br. Res. 1230: 50-60, 2008).The neural crest (NC) is a transient multipotent embryonic stem cell population that is the source of PSNs. NC cells give rise to diverse and important tissues in man, but human NC has not been studied because of the difficulty in obtaining 3-5 week human embryos. The methods described in this chapter can also be used to quickly generate large numbers of human NC for study.