Therapeutic Potential of Induced Neural Stem Cells for Parkinson's Disease.

Parkinson's disease (PD) is a chronic, neurodegenerative disorder that results from the loss of cells in the substantia nigra (SN) which is located in the midbrain. However, no cure is available for PD. Recently, fibroblasts have been directly converted into induced neural stem cells (iNSCs) via the forced expression of specific transcription factors. Therapeutic potential of iNSC in PD has not been investigated yet. Here, we show that iNSCs directly converted from mouse fibroblasts enhanced functional recovery in an animal model of PD. The rotational behavior test was performed to assess recovery. Our results indicate that iNSC transplantation into the striatum of 6-hydroxydopamine (6-OHDA)-injected mice can significantly reduce apomorphine-induced rotational asymmetry. The engrafted iNSCs were able to survive in the striatum and migrated around the medial forebrain bundle and the SN pars compacta. Moreover, iNSCs differentiated into all neuronal lineages. In particular, the transplanted iNSCs that committed to the glial lineage were significantly increased in the striatum of 6-OHDA-injected mice. Engrafted iNSCs differentiated to dopaminergic (DA) neurons and migrated into the SN in the 6-OHDA lesion mice. Therefore, iNSC transplantation serves as a valuable tool to enhance the functional recovery in PD.