Source: University of Texas Southwestern Medical Center
Date: May 31, 2012
Summary:
An immune-system receptor plays an unexpected but crucially important role in keeping stem cells from differentiating and in helping blood cancer cells grow, researchers at University of Texas Southwestern Medical Center report today in the journal Nature.
The researchers found that the human immune-inhibitory receptor LILRB2 and a corresponding receptor on the surface of mouse cells bind to several of the angiopoetic-like proteins. Further studies, Dr. Zhang said, showed that two of the seven family members bind particularly well to the LILRB2 receptor and that binding exerts an inhibitory effect on the cell, similar to a car’s brakes.
In the case of stem cells, inhibition keeps them in their stem state. They retain their potential to mature into all kinds of blood cells as needed but they don’t use up their energy differentiating into mature cells. That inhibition helps stem cells maintain their potential to create new stem cells because in addition to differentiation, self-renewal is the cells’ other major activity, Dr. Zhang said. He stressed that the inhibition doesn’t cause them to create new stem cells but does preserve their potential to do so.
In future research, the scientists hope to find subtle differences between stem cells and leukemia cells that will identify treatments to block the receptors’ action only in leukemia.
