Cellular reprogramming and its application in regenerative medicine

Ever since a technology to reprogram somatic cells into pluripotent stem cells was developed by Dr. Shinya Yamanaka’s group in 2006, its therapeutic potential has been extensively discussed. We now call the reprogrammed embryonic stem cell (ESC)-like cell an ‘induced pluripotent stem cell’ (iPSC). The beauty and power of the iPS in human case is that it avoids many ethical issues, in that unlike human ESCs (hESCs), iPSCs do not require destroying a human embryo to establish pluripotent cell lines. The iPSC holds many hopes that many human diseases may be treatable in the near future. On the other hand, there are still several issues that need to be solved prior to the therapeutic use of iPSCs in humans directly. The biggest hurdle is that, so far, there is lack of ways to completely exclude tumorigenic iPSC-derived cells. Additionally, there is an issue that immune rejection may occur, even in autologously grafted iPSCs, as was observed in monkey experiment. Nevertheless, iPSCs, combined with genetic manipulation, hold much promise that iPSCs may be used in cell therapy procedures and as tools for investigating underlying mechanisms of human diseases. This review will discuss recent progress in cellular reprogramming and its potential use in regenerative medicine.