Signaling Protein Helps Limit Damage In Heart Attack

Scientists at the Center for Translational Medicine at Thomas Jefferson University in Philadelphia have shown that a specific signaling protein is crucial to protecting the heart and helping it to adapt during a heart attack.

The protein Gi is known to have increased activity in the failing heart, but researchers have never been sure if it was helping the heart adapt to damage or if it was actually causing more heart cells to die. The Jefferson team, led by Walter Koch, Ph.D., W.W. Smith Professor of Medicine and director of the Center for Translational Medicine in the Department of Medicine at Jefferson Medical College, experimentally blocked the protein in the hearts of genetically engineered mice experiencing heart attacks. They found that the animals had greater heart damage than did similar mice with a working protein. The team reports its findings March 18, 2008, in the journal Circulation.

Gi is important in intracellular signaling, akin to a molecular switch, Dr. Koch notes. It's not a new drug target, he explains, but the activation of some receptors (such as beta-2 adrenergic receptors) that also turn on Gi could be targets.