Children's Hospital Boston's stem cell researchers have converted skin cells from an adult into cells that look and act like embryonic stem cells. The resulting cell lines, called induced pluripotent stem cells (iPS), can potentially form any cell type in the body. iPS cells allow a new way for scientists to model human diseases and may one day provide raw material for cell therapies to reverse leukemia, diabetes, Parkinson's disease, and paralysis, among other devastating conditions.
The study, led by first-author In Hyun Park, PhD, appears in the December 23 online Nature. It is similar to reports from laboratories in Japan and the University of Wisconsin that gained worldwide attention in November, but the Children's study is the first to use tissue from a volunteer research subject rather than cells purchased commercially.
"Ours is the only group to go from skin biopsy to cell line," says George Q. Daley, MD, PhD, associate director of Children's Stem Cell Program and the study's senior author. "We developed a strategy that integrates tissue procurement, culturing, and reprogramming the cells. We're now ready to apply this method to cells from patients with a variety of diseases."
Daley, one of the world's foremost experts on embryonic stem cells (ESC), is enthusiastic about the promise of reprogramming studies but far from ready to abandon experiments with embryonic stem cells. His is one of the few labs in the world pursuing both gene-based reprogramming and nuclear transfer, a technique that involves transferring the nucleus of a cell into an egg, which then allows isolation of ESCs that are genetically matched to specific patients.
Daley believes reprogramming and ESC research must advance in tandem to bring cell therapy to the clinic as quickly as possible. "Gene-based reprogramming is relatively easy and a boon to research into human disease, enabling researchers to create cell lines from patients with a specific disease and study them in the lab," he says. However, both the genes used to reprogram cells and the retroviruses that deliver them may pose a cancer risk, so significant hurdles must be overcome before iPS cells are viable for clinical applications.
Although ESCs are more difficult to produce by nuclear transfer, the cells are genetically pristine and may provide a faster and safer route to the clinic. In addition, ESC research may yield insights into reprogramming. "Understanding how to derive stem cells from embryos may teach us how to make the reprogramming process that much more efficient," says Daley.