"Many labs have reported the integration of stem cells into various types of tissues, but on a small scale," says Prof. Nadia Rosenthal, Coordinator of EMBL's Mouse Programme in Monterotondo, Italy. "This is the first study to show that stem cells can be mobilized to achieve a major regeneration of damaged tissue."
In a collaboration with the group of Antonio Musar at the University of Rome, the scientists investigated muscle tissue in mice, discovering that stem cells can travel large distances to reach an injury. They also found a special form of a protein called mIGF-1 induces the muscle to send the distress signal that summons them.
"This form of IGF-1 is produced in the cells of embryos, but that production shuts down quickly after birth," says Rosenthal. "It is also produced in quick bursts when muscles are injured. This made us think it might play a role in regenerating damaged tissues."
They created a strain of mouse whose muscle cells continue to produce mIGF-1 throughout its lifetime. In order to study the activity of stem cells at the injury site and to trace those cells back to their source, the authors generated a second strain of mouse whose bone marrow produced stem cells that bore a distinctive, fluorescent tag.
"mIGF-1 is acting like a megaphone," Musar says. "If there's an injury, muscles expressing mIGF-1 send out a very loud signal, and stem cells respond from quite far away. After birth, most animals lose the signal, w
Contact: Trista Dawson
European Molecular Biology Laboratory