Circular RNA helps protect against heart aging in mice

The researchers combined artificial intelligence with animal and cell experiments to study nucleolin, a heart-protective protein. Their analysis indicated that nucleolin could undergo phase separation—when molecules gather into liquid-like droplets—and that this capacity declined with aging. In molecular experiments, circHIPK3 bound to the RNA instructions for making nucleolin, making those instructions more stable. This preserved nucleolin’s phase separation and promoted production of ribosomes, the cell’s protein-making machinery. Raising circHIPK3 levels in knockout mice restored nucleolin levels and suppressed an aging-associated pathway.