Induced pluripotent stem cells are cells that have the same properties as embryonic stem cells but don't require the destruction of human embryos.
Reporting in the journal Cell Stem Cell, Dr. Derrick Rossi of Harvard Medical School and colleagues said they were working on new ways to make induced pluripotent stem cells or iPS cells.
These cells closely resemble embryonic stem cells -- the body's true master cells, which can give rise to all of the body's cells and tissue and which also flourish in the lab.
It takes just 3 or 4 genes to turn back the clock on skin cells or other ordinary cells, and make them behave like stem cells. But most ways of doing this involve using a virus to carry the new genes into the cell, or DNA, and these techniques can lead to other problems, including tumors.
Rossi and colleagues in stem cell leader George Daley's lab tried a new method, using RNA instead. RNA is the compound that carries out DNA's instructions.
To their surprise, RNA from the four "stem cell" genes worked to transform ordinary skin cells into iPS cells. These cells could, like stem cells, be made to form beating heart cells, nerve cells and other cell types.