Brief News on Gene Silencing
Researchers at the University of Pittsburgh have been able to use RNA interference (a method of preventing gene expression) to “increase the propensity” for stem cells derived from muscles to become bone. The researchers turned off a gene that regulates the formation of muscle cells. They also turned off a gene that inhibits a cell from responding to bone-forming signals. When the stem cells without the muscle formation gene were implanted in cells which had the bone-inhibition gene turned off, 60% of the test mice developed recognizable bone structure within three weeks. When the stem cells with the muscle gene were turned off and implanted in skeletal muscle which did not have the bone-inhibition gene turned off, they did not develop into bone, so it appears that both genes need to be repressed for this particular result to occur. The press release
does not give further details; the study is an oral presentation at a conference and not a peer-reviewed publication at this point.
While this certainly shows some potential for the muscle derived stem cells to differentiate into other types of cells, I wonder about the complication that the cells themselves needed to be receptive to the stem cells’ signaling for the differentiation into bone to occur. Stem cells obviously need particular environments in which to do their work, and any treatment that involves manipulation of the environment in which the stem cells are placed—e.g. the human body—is going to be fraught with more complexity than a “straight-forward” stem cell injection.