Breakthrough in Stem Cell Research

By on February 6, 2014

A recent breakthrough in stem cell research has been made with the discovery of a new, simple method to create stem cells. The current method used to create stem cells, called induced pluripotent stem cells, was developed in Japan in 2006. The new method, called stimulus-triggered acquisition of pluripotency (STAP), was also developed in Japan.

STAP cells were created by Haruko Obokata, a stem-cell biologist working at the RIKEN Center for Developmental Biology in Kobe, Japan. Obokata noticed that when cells were squeezed through a capillary tube, they would shrink to a size similar to the size of a stem cell. This led her to wonder if cells could revert to a pluripotent state when subjected to external stress.

Obokata subjected cells to a multitude of stressors, but three in particular had the most effect: a bacterial toxin, an acidic pH, and physical squeezing of the cells.

The next step was testing each method to see if it was, in fact, reverting the cells to a pluripotent state. Obokata injected stressed cells that were tagged with fluorescence into mouse embryos. Since pluripotent cells can differentiate to become any kind of cell, the mouse embryo was expected to be completely fluorescent. The result of Obokata’s experiment was mice that were faintly fluorescent.

The findings indicated that Obokata was on the right path, but that her work was not complete. Teruhiko Wakayama, who worked alongside Obokata, provided the missing link by suggesting that differentiated cells from newborn mice be stressed instead of cells from adult mice. The stressed cells from the newborn mice resulted in a fully fluorescent mouse.

Before her work could be accepted, Obokata needed to prove that she was in fact reverting mature cells to a pluripotent state. She decided to use T cells, which show genetic differences between the undifferentiated and mature states. This way, she would know for sure that her technique was working.

The T cell experiment was a success, and Obokata has gone on to test other cell types, such as brain and lung cells. Approximately 25% of the cells survive the acidic conditions, and 30% of those that survive actually convert to the pluripotent state. While this may sound like a small number, it’s actually more successful than the current method used now. Induced pluripotent stem cells only have a 1% conversion rate.

In addition to being an incredible breakthrough in stem cell research, the creation of STAP cells may help answer questions that have plagued the scientific community. Some scientists have found pluripotent cells in mammalian bodies, while others have struggled to do the same. Obokata has shown that is it possible that some cells in the body revert to a pluripotent state after exposure to external stress.

What makes STAP cells even more exciting is their ability to become placental cells. Neither embryonic stem cells nor induced pluripotent stem cells have the ability to form placental tissue. The ability of STAP cells to form placental tissue could change the way cloning is done, making it cheaper and easier in the future.


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