Prior to this research, in order to revert cells to an embryonic stem cell-like state, researchers would introduce DNA-based viruses into the cell. This technique, introduced to the scientific community in 2006 by Japanese researcher Shinya Yamanaka, was revolutionary but it had major flaws. By integrating viruses into the DNA of cells, previous techniques could inadvertently trigger cancers. Also, because their genome was altered, the genetic properties of the iPS cells could change, making them no longer identical to embryonic stem cells. Still, at a press conference, Rossi said that he and his research team “owe everything to Yamanaka for this study.”
At the same press conference, Doug Melton, PhD and co-director of the Harvard Stem Cell Institute, said that Rossi’s research was a major paper in the field of regenerative medicine. The study appears to have solved the major problems that hindered iPS creation under the Yamanaka technique. The big news, Melton said, was that Rossi “has figured out a way to turn a skin cell into a stem cell without any genetic modification.”
When the researchers first attempted to use RNA instead of DNA, the technique failed. When the RNA was introduced to the cells, it elicited a strong anti-viral reaction that destroyed the RNA and killed the cells. The researchers spent over a year developing synthetic RNAs that, when injected into the cell, would escape the detection of the anti-viral defense system. When they succeeded, the modified DNA could drive protein expression within the cell for weeks without any adverse effects on the cells. “This was key to our success and key to technological development,” said Rossi.
According to Rossi, researchers can use these same techniques to “direct the fate” of iPS cells towards “clinically useful cell types.” Meaning that they can determine what sort of cells the iPS cells will turn into, something that has been a challenge in the field up until now.
When asked about the Rossi’s research, Yamanaka responded in a prepared statement saying that there is not a standard method to generate iPS cells for clinical applications, but that he thought Rossi’s method “has the potential for it.”
Because of social and moral stigma, the use of stem cells in research is still a hotly debated topic. Although, Melton said, “we all want to get to the place where we don’t need human embryonic stem cells,” this in no way replaces them. Rossi called embryonic stem cells the gold standard within stem cell research.
As for the future of the project, Melton announced that the Harvard Stem Cell Institute would immediately turn over their entire iPS core to this new method in order to “efficiently make stem cells from patients with all sorts of different diseases.”