The ethical debate over embryonic stem cells is looking ever more irrelevant to the science. Scientists at the Stanford University School of Medicine have succeeded in transforming mouse skin cells directly into functional nerve cells with the application of just three genes. The cells make the change without first becoming a pluripotent type of stem cell — a step long thought to be required for cells to acquire new identities.

 

The finding – published in Nature online on January 27 -- could revolutionize the future of human stem cell therapy and recast our understanding of how cells choose and maintain their specialties in the body.

“We actively and directly induced one cell type to become a completely different cell type,” said Marius Wernig, of Stanford’s Institute for Stem Cell Biology and Regenerative Medicine. “These are fully functional neurons. They can do all the principal things that neurons in the brain do.” That includes making connections with and signaling to other nerve cells — critical functions if the cells are eventually to be used as therapy for Parkinson’s disease or other disorders.

 

They found that about 20% of the former skin cells transformed into neural cells in less than a week. That may not, at first, sound like a quick change, but it is vast improvement over iPS cells, which can take weeks. What’s more, the iPS process is very inefficient: Usually only about 1 to 2% of the original cells become pluripotent.

 

“We were very surprised by both the timing and the efficiency,” said Wernig. “This is much more straightforward than going through iPS cells, and it’s likely to be a very viable alternative.

 

The research suggests that the pluripotent stage, rather than being a required touchstone for identity-shifting cells, may simply be another possible cellular state. “It may be hard to prove,” said Wernig, “but I no longer think that the induction of iPS cells is a reversal of development. It’s probably more of a direct conversion like what we’re seeing here, from one cell type to another that just happens to be more embryonic-like.” ~ Stanford University, Jan 27