The last big development in stem cell biology took place in Japan in 2006, when Shinya Yamanaka discovered how to convert adult cells into induced pluripotent stem cells (iPS cells), for which Dr Yamanaka shared a Nobel Prize in 2012 with Sir John Gurdon.
Now in 2014, Japanese research team, led by Haruko Obokata at Riken Centre for Developmental Biology, have discovered remarkably simple way to convert mouse adult cells to pluripotent stem cells, by treating them with dilute hydrochloric acid.
The researchers exposed the haemopoietic adult cells taken from mice to a mildly (sub-lethal) acidic condition (pH 5.7) for just 25 minutes at 37 degree C. This environmental stress did not kill or damage the adult cells but surprisingly reprogrammed the adult cells to behave like pluripotent cells. This process is called Stimulus Triggered Acquisition of Pluripotency (STAP).
The stem cells so produced exhibited pluripotency on the seventh day after exposure to stress. But unlike embryonic stem cells the STAP cells do not multiplied on their own. But the researchers were able to overcome this hurdle. By using a culture medium containing a particular hormone, the STAP cells were enabled to grow into colonies.
The STAP cells were found to be capable of contributing to both embryonic and placental tissue formation; depending on the medium in which they are cultured. Whereas even the embryonic stem cells (ES cells) do not contribute to the formation of the placental tissue.
Human cells could in future be reprogrammed by the same technique, offering a simpler way to replace damaged cells or grow new organs for sick and injured people.
[The study appears in the journal Nature.]