Reprogramming of Postnatal Neurons into Induced Pluripotent Stem Cells by Defined Factors

Pluripotent cells can be derived from different types of somatic cells by nuclear reprogramming through the ectopic expression of four transcription factors, Oct3/4, Sox2, Klf4, and c-Myc. However, it is unclear whether postmitotic neurons are susceptible to direct reprogramming. Here, we show that postnatal cortical neurons, the vast majority of which are postmitotic, are amenable to epigenetic reprogramming. However, ectopic expression of the four canonical reprogramming factors is not sufficient to reprogram postnatal neurons. Efficient reprogramming was only achieved after forced cell proliferation by p53 suppression. Additionally, overexpression of repressor element-1 silencing transcription, a suppressor of neuronal gene activity, increased reprogramming efficiencies in combination with the reprogramming factors. Our findings indicate that terminally differentiated postnatal neurons are able to acquire the pluripotent state by direct epigenetic reprogramming, and this process is made more efficient through the suppression of lineage specific gene expression. STEM CELLS 2011;29:992-1000