Researchers use human skin cells to create stem cells

UCLA stem cell scientists have succeeded in reprogramming human skin cells into cells possessing the same unlimited properties as embryonic stem cells — bypassing the controversial process of using embryos or eggs for "therapeutic cloning."

Led by scientists Kathrin Plath and William Lowry, UCLA researchers used genetic alteration to turn back the clock on human skin cells and create cells that are nearly identical to human embryonic stem cells. Stem cells have the ability to become every cell type found in the human body. Four regulator genes were used to create the cells, called induced pluripotent stem cells or iPS cells.

The UCLA study confirms the work first reported in late November of researcher Shinya Yamanaka of Kyoto University and James Thompson of the University of Wisconsin. The UCLA research appears in an early online edition of the journal Proceedings of the National Academy of the Sciences. The UCLA work was completed at about the same time the Yamanaka and Thomson reports were published. Taken 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.

The implications for disease treatment could be significant. Reprogramming skin cells into embryonic stem cells could generate a potentially limitless source of immune-compatible cells for tissue engineering and transplantation medicine. Those embryonic stem cells could be prodded into becoming various cells types — beta islet cells to treat diabetes, hematopoetic cells to create a new blood supply for a leukemia patient and motor neuron cells to treat Parkinson's disease.

"Our reprogrammed human skin cells were virtually indistinguishable from human embryonic stem cells," said Plath, an assistant professor of biological chemistry, a researcher with the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research and lead author of the study. "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."

These new techniques could potentially replace somatic cell nuclear transfer (SCNT) &mdash or therapeutic cloning. This controversial method used to reprogram cells has not yet 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," said Lowry, an assistant professor of molecular, cell and developmental biology. "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."

Stem cell scientists worldwide have stressed that further research is necessary to compare these reprogrammed skin cells with stem cells derived from embryos, which are considered the "gold standard." Many technical problems, such as the use of viruses to deliver the four genes for reprogramming, also need to be overcome to produce safe iPS cells that can be used clinically.

The UCLA research team included four young scientists recruited to UCLA's new stem cell center in the wake of the passage of Proposition 71 in 2004, which created $3 billion in funding for embryonic stem cell research. The scientists were drawn to UCLA in part because of California's stem cell research-friendly atmosphere and the funding opportunities created by Proposition 71. UCLA’s Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research was launched in 2005.