Embryonic stem cells have huge potential in treating everything from cancer to diabetes because of their ability to morph into almost any other type of cell within the human body. But here’s a new twist on these controversial cells: what if you could do the reverse, and turn almost any human cell into the equivalent of an embryonic stem cell without taking the cells from an embryo in the first place?
A technique to do just that was first developed back in 2006, but it wasn’t exactly easy or quick. A new technique, however, simplifies the effort required to create what are known as pluripotent stem (iPS) cells — stem cells which can become anything from lungs to nerves to bone. As described today in two papers (1, 2) published in the journal Nature, mammalian cells can be exposed to very low levels of acid and a few other factors. This stress was enough to make the cells pluripotent in as little as 30 minutes. Not only that, they were more malleable than the iPS cells developed back in 2006.
One of the studies’ co-authors, stem-cell research Yoshiki Sasai with the RIKEN Center for Developmental Biology in Japan, told Nature that this discovery is “amazing. I would have never thought external stress could have this effect.”
The idea came from another biologist at the same facility, Haruko Obokata, who says it took her five years to persuade her colleagues that this technique would work. She developed and proved the method, which combines a very weak acid, physical squeezing and a bacterial toxin to make cells pluripotent.
The work ties into Obokata’s other research into stress. As explained on her lab’s web page, “All organisms possess instincts to survive exposures to external stresses by adapting to their environment and, to some degree, regenerating injured tissues or organs. Thus, it is not surprising to observe dramatic cellular plasticity after exposure to significant external stresses, such as an injury.”
The next step in the research was to actually prove that the post-stressed cells were, indeed, pluripotent and could be turned into other body cells. They tagged some cells with a fluorescent dye and injected them into a mouse embryo. They spread through the entire embryo, causing it to fluoresce green. (That’s the photo accompanying this article.)
Obakata told the BBC that the discovery was surprising, but said “It’s exciting to think about the new possibilities these findings offer us, not only in regenerative medicine, but cancer as well.”
Chris Mason, a University College London professor of regenerative medicine who was not affiliated with the two studies, told the BBC that this is a “game changer” and that it could lead to “personalized, reprogrammed cell therapies” to treat a variety of conditions.
Obokata is now continuing her experiments to see if the technique will also work with cells from adult mice (she previously used newborns) as well as humans.
article by John Platt