Stem cell research pioneer James Thomson and colleagues at the University of Wisconsin have generated cells that appear to function like embryonic stem cells by “reprogramming” human skin cells. These cells could potentially be used to create different types of cells that can replace damaged cells in patients with diseases like diabetes or Parkinson’s. Photo by Jeff Miller, University of WisconsinMadison.
Thomson, a pioneer in stem cell research, directed the group at the Wisconsin NPRC that reported the first isolation of embryonic stem cell lines from a rhesus macaque in 1995. He then led his group to the first successful isolation of human embryonic stem cell lines in 1998. Last year, one week after the announcement of the Oregon team’s success, Thomson’s team, along with a team of Japanese scientists working independently, reported that human skin cells could be transformed into stem cells without the use of living egg cells or embryos.
Thomson and colleagues used viruses as laboratory tools to introduce four genes into the genome of human skin cells, causing the skin cells to become pluripotent stem cells. Although stem cells generated through this technique, called induced pluripotent stem (iPS) cells, appear to behave like ordinary embryonic stem cells, more tests are needed to precisely determine the properties of iPS cells. Thomson’s team and other researchers are also working on finding ways to remove the “extra” genes once they are no longer needed.
If iPS cells prove to be like embryonic stem cells and are able to produce any type of cell in the body, they could be used to replace damaged cells and tissues using a patient’s own cells. Because no human eggs or embryos would be used, the technique would circumvent the ethical and legal issues that surround the use of embryonic stem cells in therapy. But before any therapies can be used with patients, “more work in the primate centers needs to be performed showing that therapies based on iPS cells can be done and are safe,” says Thomson.
These advances, which have generated much excitement among stem cell researchers, build on many years of work developing the necessary tools and expertise at all NPRCs. “The base grants to the centers allowed the buildup of the intellectual and physical infrastructure needed to accomplish breakthroughs such as these,” says Harding. And primate centers will undoubtedly continue to play an important role in regenerative medicine as more discoveries are made.
The research described in this article is supported in part by base grants to the Oregon National Primate Research Center and the Wisconsin National Primate Research Center, two of eight NCRR-funded primate research centers nationwide. Thomson also was the recipient of an NCRR grant that funded improvements in viral vectors that were ultimately used in the induced pluripotent stem cell studies, as well as grants from the Charlotte Geyer Foundation and the National Institute of General Medical Sciences. Mitalipov’s work also was supported by a grant from the National Institute of Neurological Disorders and Stroke.
Additional Reading: Yu, J., Vodyanik, M. A., Smuga-Otto, K., et al., Induced pluripotent stem cell lines derived from human somatic cells. Science 318:1917–1920, 2007. Takahashi, K., Tanabe, K., Ohnuki, M., et al., Induction of pluripotent stem cells from human fibroblasts by defined factors. Cell 131:861–872, 2007. Byrne, J. A., Pedersen, D. A., Clepper, L. L., et al., Producing primate embryonic stem cells by somatic cell nuclear transfer. Nature 450:497–502, 2007.