Therapeutic function of iPSCs-derived primitive neuroepithelial cells in a rat model of Parkinson's disease.

Induced pluripotent stem cells (iPSCs) are a promising unlimited source for cell replacement therapy of neurodegenerative disorders, including Parkinson's disease (PD). In the present study, rat iPSCs-derived primitive neuroepithelial cells (RiPSCs-iNECs) were successfully induced from rat iPSCs (RiPSCs) following two major developmental stages, and could generate neurospheres and differentiated into both neurons and astrocytes in vitro. Then, the RiPSCs-iNECs-GFP+ were unilaterally transplanted into the right substantia nigra (SN) of 6-hydroxydopamine-lesioned rat models of PD. The results demonstrated that the grafted RiPSCs-iNECs could survive in parkinsonian rat brain for at least 150 days, and many of them differentiated into tyrosine hydroxylase (TH)-positive cells. Furthermore, the PD model rats grafted with RiPSCs-iNECs exhibited a significant functional recovery from their parkinsonian behavioral defects. Histological studies showed that RiPSCs-iNECs could differentiate into multiple types of neurons including dopaminergic neurons, GFAP, Pax6, FoxA2 and DAT-positive cells, and induced dopaminergic neurons extended dense neurites into the host striatum. Thus, iPSCs derived primitive neuroepithelial cells could be an attractive candidate as a source of donor material for the treatment of PD, but the molecular mechanism needs further clarification.