Abstract
Recently, various hypothalamic neurons have been successfully engineered from pluripotent stem cells, including mouse and human embryonic stem cells. Because pluripotent cells need to undergo stepwise changes during organogenesis, developmental analyses on the hypothalamus have been inevitable for numerous transcription factors that determine specification, survival, and migration during the formation of specific neurons. Hypothalamic progenitor cells arise from the retina and anterior neural fold homeobox (Rax)+ ventral part of the ventricular zone at embryonic day 10.5 (E10.5), and orthopedia (Otp) and steroidgenic factor-1 (SF-1) respectively appear in the dorsal and ventral regions at E13.5, which subsequently produce specific transcription factors required for the final maturation of hypothalamic neurons. In the pluripotent stem cells, rostrodorsal hypothalamus-like progenitors expressing retina and anterior neural fold homeobox are generated from floating aggregates in serum-free conditions with minimized exogenous patterning signaling. A certain population of the Rax+ progenitors generate Otp+ neuronal precursors, which subsequently develop into various dorsal and lateral hypothalamic neurons, including arginine vasopressin (AVP) and oxytocin neurons. Alternatively, early exposure to sonic hedgehog (Shh) induces differentiation markers including SF-1, specific for rostral–ventral hypothalamic-like precursors that eventually produce neuropeptide Y (NPY) and pro-opio-melanocortin (POMC). In conclusion, it is now possible to induce most types of hypothalamic neurons from pluripotent stem cells. Application of these cells would have advantages for studies on specification, migration, drug development, and regenerative medicine.
