Dual small-molecule targeting of SMAD signaling stimulates human induced pluripotent stem cells toward neural lineages

Abstract

© 2014 Wattanapanitchet al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Incurable neurological disorders such as Parkinson's disease (PD), Huntington's disease (HD), and Alzheimer's disease (AD) are very common and can be life-threatening because of their progreive disease symptoms with limited treatment options. To provide an alternative renewable cell source for cell-based transplantation and as study models for neurological diseases, we generated induced pluripotent stem cells (iPSCs) from human dermal fibroblasts (HDFs) and then differentiated them into neural progenitor cells (NPCs) and mature neurons by dual SMAD signaling inhibitors. Reprogramming efficiency was improved by supplementing the histone deacethylase inhibitor, valproic acid (VPA), and inhibitor of p160-Rho aociated coiled-coil kinase (ROCK), Y-27632, after retroviral transduction. We obtained a number of iPS colonies that shared similar characteristics with human embryonic stem cells in terms of their morphology, cell surface antigens, pluripotency-aociated gene and protein expreions as well as their in vitro and in vivo differentiation potentials. After treatment with Noggin and SB431542, inhibitors of the SMAD signaling pathway, HDF-iPSCs demonstrated rapid and efficient differentiation into neural lineages. Six days after neural induction, neuroepithelial cells (NEPCs) were observed in the adherent monolayer culture, which had the ability to differentiate further into NPCs and neurons, as characterized by their morphology and the expreion of neuron-specific transcripts and proteins. We propose that our study may be applied to generate neurological disease patient-specific iPSCs allowing better understanding of disease pathogenesis and drug sensitivity aays.