Autologous dopamine (DA) neurons are a new cell source for replacement therapy of Parkinson’s disease (PD). In this study, we tested the safety and efficacy of autologous induced pluripotent stem cell (iPSC)-derived DA cells for treatment of a cynomolgus monkey PD model. Monkey bone marrow mesenchymal cells were isolated and induced to iPSCs, followed by differentiation into DA cells using a method with high efficiency. Autologous DA cells were introduced into the brain of a cynomolgus monkey PD model without immunosuppression; three PD monkeys that had received no grafts served as controls. The PD monkey that had received autologous grafts experienced behavioral improvement compared with that of controls. Histological analysis revealed no overgrowth of grafts and a significant number of surviving A9 region-specific graft-derived DA neurons. The study provided a proof-of-principle to employ iPSC-derived autologous DA cells for PD treatment using a nonhuman primate PD model.

Human neural stem cells (NSCs) hold great promise for research and therapy in neural diseases. Many studies have shown direct induction of NSCs from human fibroblasts, which require an invasive skin biopsy and a prolonged period of expansion in cell culture prior to use. Peripheral blood (PB) is routinely used in medical diagnoses, and represents a noninvasive and easily accessible source of cells. Here we show direct derivation of NSCs from adult human PB mononuclear cells (PB-MNCs) by employing episomal vectors for transgene delivery. These induced NSCs (iNSCs) can expand more than 60 passages, can exhibit NSC morphology, gene expression, differentiation potential, and self-renewing capability and can give rise to multiple functional neural subtypes and glial cells in vitro. Furthermore, the iNSCs carry a specific regional identity and have electrophysiological activity upon differentiation. Our findings provide an easily accessible approach for generating human iNSCs which will facilitate disease modeling, drug screening, and possibly regenerative medicine.

Autologous neural stem cells (NSCs) may offer a promising source for deriving dopaminergic (DA) cells for treatment of Parkinson's disease (PD).Methods: By using Sendai virus, human peripheral blood mononuclear cells (PBMNCs) were reprogrammed to induced NSCs (iNSCs), which were then differentiated to dopaminergic neurons in vitro. Whole-genome deep sequencing was performed to search for mutations that had accumulated during the reprogramming and expansion processes. To find the optimal differentiation stage of cells for transplantation, DA precursors obtained at various differentiation time points were tested by engraftment into brains of naïve immunodeficient mice. At last, the safety and efficacy of iNSC-derived DA precursors were tested by transplantation into the striatum of immunodeficient PD mouse models.Results: PBMNC-derived iNSCs showed similar characteristics to fetal NSCs, and were able to specifically differentiate to DA neurons with high efficiency in vitro. The sequencing data proved that no harmful SNVs, Indels and CNVs were generated during the reprogramming and expansion processes. DA precursors obtained between differentiation day 10 to 13 in vitro were most suitable for transplantation when a balanced graft survival and maturation were taken into account. Two weeks after transplantation of DA precursors into mouse PD models, the motor functions of PD mice started to improve, and continued to improve until the end of the experiments. No graft overgrowth or tumor was observed, and a significant number of A9-specific midbrain DA neurons were surviving in the striatum.Conclusion: This study confirmed the efficacy of iNSC-derived DA precursors in a mouse PD model, and emphasized the necessity of genomic sequencing and vigorous safety assessment before any clinical translation using iNSCs.

Oligodendrocyte progenitor cells (OPCs) hold great promise for treatment of dysmyelinating disorders, such as multiple sclerosis and cerebral palsy. Recent studies on generation of human OPCs mainly use human embryonic stem cells (hESCs) or neural stem cells (NSCs) as starter cell sources for the differentiation process. However, NSCs are restricted in availability and the present method for generation of oligodendrocytes (OLs) from ESCs often requires a lengthy period of time. Here, we demonstrated a protocol to efficiently derive OPCs from human induced pluripotent stem cells (hiPSCs) by forced expression of two transcription factors (2TFs), Sox10 and Olig2. With this method, PDGFRα + OPCs can be obtained in 14 days and O4 + OPCs in 56 days. Furthermore, OPCs may be able to differentiate to mature OLs that could ensheath axons when co-cultured with rat cortical neurons. The results have implications in the development of autologous cell therapies. oligodendrocyte progenitors, iPSC, differentiation, demyelination Citation: