Small circles of DNA are the key to a new and simple way of transforming fat stem cells from human induced pluripotent stem (IPS) for use in regenerative medicine, according to scientists at the University School of Medicine in Stanford. Unlike other techniques, using this method does not use viruses to introduce genes into cells or permanently alter the genome of a cell.
A.R. | 8 February 2010
The researchers believe that this new technique is a significant step toward the use of such cells in humans. Its ease of use and relative safety could pave the way for future approval.
The Stanford researchers used minicircles (rings of DNA with half the size usually used for reprogramming). The finding brings together different areas of research at Stanford. The laboratory of Mark Kay, Dennis Farrey Family Professor in Paediatrics and professor of genetics, who invented the minicircles several years ago. Meanwhile, Michael Longaker, director of Stanford's Institute for Stem Cell Biology and Regenerative Medicine, discovered the unusual prevalence and flexibility of development of stem cells from human fat. Meanwhile, Joseph Wu, a cardiologist, was researching how to create stem cell lines from patients with severe heart disease.
The vector of the reprogramming of the minicircles works well because it requires only four genes to reprogram the cells (and one additional gene, that of the fluorescent protein used to trace the minicircles). Unlike the AND circles commonly used, these do not contain bacterial DNA, which means they are less likely to be perceived as foreign by the body. The expression of genes is also more robust, and the smaller size allows them to enter cells more easily into cells. Finally, because they do not reproduce naturally, these are lost during cell division.
