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Cells of Mice Get Radically Altered

Posted on: Thursday, 7 June 2007, 06:00 CDT

By Dan Vergano

Cells from adult mice have been genetically reprogrammed to mimic embryonic stem cells, the highly coveted cells that could help grow replacement tissues to treat disease, biologists reported Wednesday.

The findings, by three teams publishing in the journals Nature and Cell Stem Cell, mean the reprogrammed cells may offer a non-controversial way -- unlike with human embryonic stem cells -- to make rejection-free tissues for transplant patients. But research still hasn't shown that the same cells will work in humans too, the study's authors say.

"A human is not a mouse," cautions Marius Wernig of the Whitehead Institute for Biomedical Research in Cambridge, Mass., who led one of the Nature studies. But "we have reprogrammed mature adult cells into ones virtually identical to embryonic stem cells. I would not have believed this was possible."

In the studies, the teams genetically altered connective tissue cells called fibroblasts to give them the flexibility to turn into all other kinds of tissue, just as in embryonic stem cells. Embryonic stem cells are capable of becoming any cell in the body and hold the promise of generating tissue that can treat such diseases as diabetes and cancer.

With a method first proposed by Kyoto University's Shinya Yamanaka, the teams used viruses to deliver four genes into fibroblasts and allowed the reprogrammed cells to divide for at least seven days. The selected cells demonstrate all the capabilities of embryonic stem cells, says Cell Stem Cell report senior author Konrad Hochedlinger of the Harvard Stem Cell Institute. The teams injected the cells into early mouse embryos, which were implanted into the wombs of female mice, producing mouse pups, a final test of their flexibility, Hochedlinger says.

Though embryonic stem cells are seen as holding great biomedical promise, creating the cells requires the destruction of embryos, a source of controversy.

"Because adult cell reprogramming does not raise the moral problem of creating or destroying embryos, it may offer a way for people of all faiths and all ethical backgrounds to study, use, subsidize and enjoy any therapeutic benefits of 'pluripotent' stem cell research," Richard Doerflinger of the U.S. Conference of Catholic Bishops, an opponent of embryonic cell research, says by e-mail.

"The studies are exciting and important," says biologist George Daley of Children's Hospital Boston. Even so, he cautions that the reprogrammed cells carry multiple viruses, while embryonic stem cells are free of genetic modifications. (c) Copyright 2005 USA TODAY, a division of Gannett Co. Inc.

Source: USA TODAY

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