Age-related NADH oxidase (arNOX) activity is significantly reduced in coelomic fluid of long-lived sea urchins

Age-related NADH oxidase (arNOX) is a cell surface protein shed into the circulation and other body fluids, which generates superoxide. The activity increases with age in human tissues and body fluids (serum, saliva, and perspiration) and is a potential source of age-related oxidative damage. We measured arNOX activity in the coelomic fluid of sea urchin species with different life spans. Coelomic fluid of long-lived sea urchin species Strongylocentrotus purpuratus and Strongylocentrotus franciscanus exhibited low levels of arNOX compared to the short-lived urchin species Lytechinus variegatus. arNOX activity was positively correlated with animal size in L. variegatus, whereas with S. purpuratus and S. franciscanus, arNOX activity and animal size were inversely correlated. The inverse correlation of arNOX activity with life span and decreased levels of arNOX with age in the long-lived species is consistent with a contribution of reduced arNOX activity to slower aging.