Identification of the redox-stress signaling threshold (RST): Increased RST helps to delay aging in C. elegans

Reactive oxygen species (ROS) play a dual role since they can be either beneficial or harmful to living systems. With increasing ROS concentrations, the roles of ROS change from advantageous to detrimental. There seems to be a concentration threshold that determines the transition from their advantageous to detrimental effects. If we purposefully increase the threshold, that is, increase the range of ROS that plays an advantageous role, it should be beneficial for individuals. To test this hypothesis, in C. elegans, the effects of oxidative challenge induced by different concentrations of paraquat (PQ) on nematode lifespan were evaluated. We found that there is a maximum level below which redox stress has benefits and named this threshold as "Redox-stress Signaling Threshold (RST)". Furthermore, we found that starvation (or heat stress or exercise) stimuli at early stage in C. elegans could increase the RST, indicating that this value is not fixed and can be increased by the adaptive response. More intriguingly, we found that increasing RST could improve Redox-stress Response Capacity (RRC) and healthspan, suggesting that increasing the RST value through early stimulation will be an effective strategy to delay aging.