LA JOLLA-The ability to switch out one gene for another in a line of living stem cells has only crossed from science fiction to reality within this decade. As with any new technology, it brings with it both promise--the hope of fixing disease-causing genes in humans, for example--as well as questions and safety concerns. Now, Salk scientists have put one of those concerns to rest: using gene-editing techniques on stem cells doesn't increase the overall occurrence of mutations in the cells. The new results were published July 3 in the journal Cell Stem Cell.
"The ability to precisely modify the DNA of stem cells has greatly accelerated research on human diseases and cell therapy," says senior author Juan Carlos Izpisua Belmonte, professor in Salk's Gene Expression Laboratory. "To successfully translate this technology into the clinic, we first need to scrutinize the safety of these modified stem cells, such as their genome stability and mutational load."
When scientists want to change the sequence of a stretch of DNA inside cells--either for research purposes or to fix a genetic mutation for therapeutic purposes--they have their choice of two methods. They can use an engineered virus to deliver the new gene to a cell; the cell then integrates the new DNA sequence in place of the old one. Or scientists can use what's known as custom targeted nucleases, such as TALEN proteins, which cut DNA at any desired location. Researchers can use the proteins to cut a gene they want to replace, then add a new gene to the mix. The cell's natural repair mechanisms will paste the new gene in place.
Previously, Belmonte's lab had pioneered the use of modified viruses, called helper-dependent adenoviral vectors (HDAdVs) to correct the gene mutation that causes sickle cell disease, one of the most severe blood diseases in the world. He and his collaborators used HDAdVs to replace the mutated gene in a line of stem cells with a mutant-free version,
|Contact: Kristina Grifantini|