In this study, we have validated a scalable protocol for efficient generation of A9 dopaminergic neurons from multiple iPSC lines using a completely defined xeno-free system that we have developed for hESC differentiation [5]. Using this procedure, we showed that neural stem cells (NSCs) derived from two human iPSC lines adapted to defined media were able to differentiate into functional dopaminergic neurons similar to hESCs in terms of time course, neural patterning, and efficiency of generation of dopaminergic neurons. Side by side comparison of iPSCs and hESCs as well as of iPSC- and hESC-derived NSCs and dopaminergic neurons revealed that iPSCs were overall similar to hESCs in gene expression profiles. In addition, we showed that iPSC-derived dopaminergic neurons could improve symptoms of PD in a preclinical rodent model, and be genetically modified efficiently. Our approach will facilitate subsequent adaptation of protocols to GMP standards which is a prerequisite for progression toward clinical trials.
