Reversing the biological clock – generation of induced pluripotent stem cells

In our body, skin cells generate only skin, muscle cells make only muscle and so forth. However, our whole body was generated from a single cell, a fertilized egg. In the beginning of embryo development, until about 1 week after fertilization, we have cells that can generate all ~300 different cell types which we have in our adult body. This ability to make all cell types is called ‘pluripotent’. After this stage, pluripotent cells start being specialized to form a body. Once they are specialized, they do not generate different cell types any more. However, in 2006 a group of scientists found that any specialized cells can become uncommitted pluripotent cells by artificially manipulating only 4 genes simultaneously. The resulting cells called induced pluripotent stem cells (iPS cells) could generate any cell types in the body, thus quickly became an extremely useful tools to study human diseases and discover drugs, or a potential source for cell transplantation therapy. Nevertheless, this cellular reprogramming is very inefficient. Only <1% of specialised cells can successfully become iPS cells and we still know little how and why the manipulation of only 4 genes can induce pluripotency, erasing the character of specialized cells. In this talk, Dr Kaji will present their research carried out in order to illuminate the molecular mechanisms of cellular reprogramming in the past 10 years.