A Novel Method for the Generation of Region-Specific Neurons and Neural Networks from Human Pluripotent Stem Cells.

Stem cell-based neuronal differentiation has provided a unique opportunity for disease modeling and regenerative medicine. We have reported a novel culture condition and method for generating neuronal progenitors and neural networks from human embryonic and induced pluripotent stem cells without any genetic manipulation. Neurospheres generated under 10% CO2 with Supplemented Knockout Serum Replacement Medium (SKSRM) had doubled the expression of NESTIN, PAX6 and FOXG1 genes compared to the neurospheres generated under 5% CO2 . Furthermore, an additional step (AdStep) was introduced to fragment the neurospheres, which increased the expression of neuronal progenitor genes NEUROD1, NEUROG2, TBR1, TBR2, and NOTCH1 and the formation of the neuroepithelial-type cells. With the supplements, neuronal progenitors further differentiated into different layers of cortical, pyramidal, GABAergic, glutamatergic, cholinergic, dopaminergic and purkinje neurons within 27-40 days, which is faster than traditional neurodifferentiation protocols (42-60 days). Furthermore, our in vivo studies indicated that neuronal progenitors derived under our culture conditions with "AdStep" showed significantly increased neurogenesis in Severe Combined Immunodeficiency (SCID) mouse brains. This neurosphere-based neurodifferentiation protocol is a valuable tool for studies neurogenesis, neuronal transplantation and high throughput screening assays.