Stanford researchers change cells directly

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

Michael Cook
embryonic stem cells
iPS cells
stem cells

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Michael Cook

Michael Cook edits BioEdge, a bioethics newsletter, and MercatorNet, an on-line magazine whose focus is human dignity. He writes from Sydney, Australia.

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