Defined Conditions for Neural Commitment and Differentiation

Pluripotent mouse embryonic stem (ES) cells can be expanded in culture indefinitely, retaining the capacity to produce seemingly every type of fetal and adult cell. Current methods are empirical with outcomes that are invariably heterogeneous and often poorly reproducible. Some progress has been made with controlling the intermediate stages of lineage progression, but mastering the full sequence of steps necessary for efficient generation of any particular terminally differentiated phenotype remains elusive. There are two major challenges: first to understand and manipulate lineage choices; second to develop culture conditions that support the viability and maturation of progenitor and terminal phenotypes in vitro. The most widely used method to trigger neural development from ES cells is cell aggregation in suspension culture followed by treatment with retinoic acid. This chapter describes defined conditions for conversion of ES cells to neural fates in monolayer culture.