Scientists Reprogram Human Skin Cells Into Embryonic Stem Cells
MONDAY Feb. 11, 2008 -- U.S. scientists say they've reprogrammed human skin cells into ones with the same blank-slate properties as embryonic stem cells, a breakthrough that could aid in treating many diseases while sidestepping controversy.
Human embryonic stem cells have the ability to become every cell type found in the human body. Being able to create these cells en masse and without using human eggs or embryos could generate a potentially limitless source of immune-compatible cells for tissue engineering and transplantation medicine, said the scientists, from the University of California, Los Angeles.
The researchers genetically altered human skin cells using four regulator genes, according to findings published online in the Feb. 11 edition of the journal Proceedings of the National Academy of the Sciences.
The result produced cells called induced pluripotent stem cells, or iPS cells, that are almost identical to human embryonic stem cells in function and biological structure. The reprogrammed cells also expressed the same genes and could be coaxed into giving rise to the same cell types as human embryonic stem cells, the researchers said.
"Our reprogrammed human skin cells were virtually indistinguishable from human embryonic stem cells," lead author Kathrin Plath, an assistant professor of biological chemistry and a researcher with the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, said in a prepared statement. "Our findings are an important step towards manipulating differentiated human cells to generate an unlimited supply of patient specific pluripotent stem cells. We are very excited about the potential implications."
The UCLA findings confirm similar work first reported in late November by researcher Shinya Yamanaka at Kyoto University and James Thompson at the University of Wisconsin. Together, the studies demonstrate that human iPS cells can be easily created by different laboratories and are likely to mark a milestone in stem cell-based regenerative medicine, Plath said.
Reprogramming adult stem cells into embryonic stem cells has significant implications for disease treatment. A patient's skin cells, for example, could be reprogrammed into embryonic stem cells that could be prodded into becoming beta islet cells to treat diabetes, hematopoetic cells to create a new blood supply for a leukemia patient, or motor neuron cells to treat Parkinson's disease, the researchers said.
These new techniques to develop stem cells could potentially replace a controversial method to reprogram cells called somatic cell nuclear transfer (SCNT), sometimes referred to as therapeutic cloning. To date, therapeutic cloning has not been successful in humans.
"Reprogramming normal human cells into cells with identical properties to those in embryonic stem cells without SCNT may have important therapeutic ramifications and provide us with another valuable method to develop human stem cell lines," study first author William Lowry, an assistant professor of molecular, cell and developmental biology, said in a prepared statement. "It is important to remember that our research does not eliminate the need for embryo-based human embryonic stem cell research, but rather provides another avenue of worthwhile investigation."
However, top stem cell scientists worldwide stress further research comparing reprogrammed cells with stem cells derived from embryos -- considered the gold standard -- is necessary.
The U.S. National Institutes of Health has more about stem cells.
Posted: February 2008