Skin cells made to mimic stem cells

Alan Boyle Science editor • Profile • E-mail

Two research groups have found different genetic recipes to give ordinary skin cells the power to turn into virtually any kind of human tissue, just as embryonic stem cells do.

If the recipes live up to their promise, they could someday end the ethical debate over embryonic stem cell research — and usher in an era when a person's own cells could be manipulated to mend a broken spinal cord, heal a damaged heart or regenerate other failing tissues.

But in their current state, the recipes are too risky for disease treatment, and even the scientists behind the latest studies cautioned that therapies are still years away. In announcing their discoveries, they emphasized that much more research still needs to be done on stem cells that have been derived from human embryos.

"It's not the time to say human embryonic stem cell research is dead," James Thomson, a biologist at the University of Wisconsin in Madison, who is behind a study appearing in the journal Science, told msnbc.com.

Kyoto University's Shinya Yamanaka, the principal author of a study published by the journal Cell, echoed that view, saying it would be "premature" to conclude that the cells created in his lab could replace embryonic stem cells.

Science This photomicrograph shows neural tissue derived from human skin cells that were genetically modified to behave like embryonic stem cells. The black scale bar represents 0.1 millimeters, or roughly the width of a human hair.

Nevertheless, the two sets of findings quickly transformed the debate over stem cells and cloning.

Edinburgh University's Ian Wilmut — who led the research that gave rise to Dolly, the first cloned sheep, a decade ago — has been quoted as saying he's abandoning his cloning efforts to adopt the new approach. But another stem cell pioneer, Advanced Cell Technology's Robert Lanza, said he was alarmed at Wilmut's statement and worried that the new studies would drown out other stem cell research like a "tidal wave."

"This work represents a tremendous scientific milestone, the biological equivalent of the Wright brothers' first airplane," Lanza, ACT's chief scientific officer, told msnbc.com. "It's a bit like turning lead into gold. But this is not over by a long shot. It's extremely important to temper this announcement with caution."

Lanza said he would continue his work on a technique to extract stem cells from human embryos without destroying the embryo itself.

William Hurlbut, a physician and consulting professor at Stanford University Medical Center who also serves on the President's Council on Bioethics, said the research on cell reprogramming "essentially takes the stem cell issue off the political agenda."

"It's very encouraging, and it's pretty obvious we're going to find a consensus solution," Hurlbut told msnbc.com. "It's exciting, because we're not going to be fighting about this."

For years, Hurlbut has been at odds with the proponents of embryonic stem cell research because he is opposed to cloning or destroying human embryos.

No embryos required
The recipes detailed in Cell and Science don't require embryos at all — or even unfertilized human egg cells. Instead, the technique involves slipping a set of four genes into skin cells, in a specially prepared culture that coaxes the cells to behave like an embryonic stem cell.

Like embryonic stem cells, these reprogrammed cells become "pluripotent" — that is, they're capable of turning themselves into virtually any tissue type in the human body, including neurons and heart tissue. They also exhibit many of the other biochemical properties of embryonic stem cells, although they're not genetically identical to stem cells.

Yamanaka's research builds on previous work that he and his colleagues conducted with mice. They used the same four genes that made mouse cells pluripotent — Oct3/4, Sox2, c-Myc and Klf4 — but found that they had to adjust the culture to suit human cells rather than mouse cells.

Meanwhile, even before Yamanaka's group published their mouse research, the research group at Thomson's Wisconsin lab started screening 100 genetic factors linked to embryonic development. The researchers zeroed in on four genes that produced the pluripotent cells most efficiently, said a co-author of the Science paper, Junying Yu of the Wisconsin National Primate Research Center and the Genome Center of Wisconsin.

Two of the genes turned out to be the same (Oct4 and Sox2), but two others were different (Nanog and Lin28).

Print this Email this Blog this  IM this

MORE FROM CLONING AND STEM CELLS

Cloning and stem cells Section Front

Embryonic stem cells coaxed into key heart cells USDA won't lift ban on cloned food soon Scientists make human-cow embryos Cloned cells show promise in Parkinson's mice How far would you go for a cure? Bone docs look to biology for future Brazilian court to rule on stem cell research Stem cells treat diabetes in mice Germany considers changing stem cell laws Patient grows new jaw from own stem cells Cloning and stem cells Section Front   Add Cloning and stem cells headlines to your news reader: