Generation of induced pluripotent stem cells from cord blood using OCT4 and SOX2

Induced pluripotent stem (iPS) cells have generated interest for regenerative medicine as they allow for producing patient-specific progenitors in vitro with potential value for cell therapy. In many instances, however, an off-the-shelf approach would be desirable, such as for cell therapy of acute conditions or when the patient's somatic cells are altered as a consequence of chronic disease or aging. Cord blood (CB) stem cells appear ideally suited for this purpose as they are newborn, immunologically immature cells with minimal genetic and epigenetic alterations, and several hundred thousand immunotyped CB units are readily available through a worldwide network of CB banks. Here, we show that CB stem cells can be reprogrammed to pluripotency by retroviral transduction with OCT4, SOX2, KLF4, and c-MYC, in a process that is extremely efficient and fast. The resulting CB-derived iPS (CBiPS) cells are phenotypically and molecularly indistinguishable from human embryonic stem (hES) cells. Furthermore, we show that generation of CBiPS can be efficiently achieved without the use of the c-MYC and KLF4 oncogenes and just by overexpression of OCT4 and SOX2. Our studies set the basis for the creation of a comprehensive bank of HLA-matched CBiPS cells for off-the-shelf applications. Human cord blood cells enriched for progenitors by sorting with the CD133 antigen were reprogrammed using either 2 factors (Oct4 and Sox2) or 4 factors (Oct4, sox2, Klf4 and c-Myc) to give rise to induced pluripotent stem cells (CBiPS). Using genome-wide microarray profiling, we compare expression profiles of the starting population (CD133+), the reprogrammed cells either with 2 or 4 factors (CBiPS 2F and 4F) and a population of embryonic stem cells as reference (ES2), each in 2 replicates.