Treatment with small molecules is an important milestone towards the induction of pluripotency in neural stem cells derived from human cord blood.

Induced pluripotent stem cells (iPSC) are central to developing new strategies for personalized regenerative medicine without the use of embryonic material. This become evident since Yamanaka’s group for the first time reprogrammed mice and human fibroblasts (Takahashi and Yamanaka 2006, Takahashi et al. 2007) to the pluripotent stage. Since that time iPS cells have been generated from most types of human somatic cells by transgenic expression of Oct4 (Pou5f1), Sox2, Klf4 and Myc transcription factors usually delivered to the cells by viral vectors (Maherali and Hochedlinger 2008, Braun et al. 2012). To reduce potential risks of tumor induction or genomic instability, research has focused on “viral free” delivery systems of reprogramming factors (Stadtfeld et al. 2008). The safest, though not most efficient, is the recombinant protein-based approach. Specially designed charged polyarginine domains can bind to plasma membrane and facilitate protein transmembrane penetration (Kim et al. 2009, Zhou et al. 2009). In this report, for reprogramming purpose, stable HEK 293 (Human Embryonic Kidney 293 cells) cell lines producing OCT4, KLF4 and SOX2 recombinant proteins tagged with polyarginine residues have been established according to the published protocol (Kim et al. 2009). Treatment with small molecules is an important milestone towards the induction of pluripotency in neural stem cells derived from human cord blood