Signals involved in neural differentiation of human embryonic stem cells.

Neural differentiation from embryonic stem cells involves progressive stages of neural induction, expansion and maintenance of neural stem/progenitor cells, and differentiation to neurons and glia. Our understanding of the signals involved in each of these processes is primarily based on our knowledge of neural development during embryogenesis. This review will focus on the signalling pathways that have been identified to play a role in neural differentiation of human embryonic stem cells (hESCs), including their induction to neuroectoderm, maintenance and expansion of hESC-derived neurospheres, differentiation to neurons and specification to specific neuronal lineages. Understanding the signals involved in each of these stages is important for optimising methods to derive specific cell types for transplantation therapies, as well as for providing insight into the mechanisms of human neurogenesis.