Because the adult human heart cannot repair itself the way skin does, scientists have studied ways to reprogram heart cells to regenerate after heart attacks. Heart cells have very stable identities, however, and are resistant to being reprogrammed. Scientists at Sanford Burnham Prebys Medical Discovery Institute and collaborators at The Johns Hopkins University School of Medicine published findings July 17, 2026, in Nature Communications uncovering a new mechanism used by cells to protect their cellular identities and ward off reprogramming attempts. Continued study of the obstacles to cellular reprogramming may lead to treatments that can help the heart fix itself after injury.