[QUOTE]Using a relatively new technology called RNA interference to turn off genes that regulate cell differentiation, University of Pittsburgh researchers have demonstrated they can increase the propensity of muscle-derived stem cells (MDSCs) to become bone-forming cells. Based on these results, the investigators believe that by turning off specific genetic factors they can control the capacity of MDSCs as a means of treating various musculoskeletal diseases and injuries.

RNA interference is a simple yet powerful technique that uses short interfering RNAs (siRNAs) - small molecules that prevent a gene from being expressed - to turn off the production of specific proteins in a cell. In their study, the Pitt researchers generated siRNAs to two mouse genes: MyoD1, a master gene that regulates the formation of muscle cells or fibers (myogenesis), and Smad6, which encodes a molecule that specifically inhibits a cell's ability to respond to bone-forming, or osteogenic, signals.


"By understanding the genetic mechanisms that regulate a cell's propensity to differentiate into one type of cell line over another, we may be able to regulate their ability to generate bone for the treatment of various diseases and injuries of the musculoskeletal system, such as osteoporosis or severe fractures," said first author Jonathan B. Pollett, Ph.D., research associate, department of orthopaedic surgery, {/QUOTE}