Mitohormetic effects of rotenone drastically depend on age

Hormesis refers to a biphasic intensity-dependent response to stressors where low-intensity or short-duration exposure to potentially noxious stressors induces long-lasting adaptations that have positive physiological effects [1]. It was proposed that life-extending interventions, such as calorie restriction, retard aging via their hormetic action [2]. More recently, it was shown that a transient burst of reactive oxygen species is required to induce the effects of calorie restriction [3], physical exercise [4], inhibition of the insulin/IGF-I pathway [5] and metformin [6]. We have previously shown that partial inhibition of complex I of the respiratory chain by a low dose of the poison rotenone (ROT) administered in middle age increases the lifespan and reverts the transcriptomic signature of aging in a vertebrate species [7], an example of a hormetic effect. Here, we asked whether ROT treatment started at young age induces larger effects on life-span and transcriptome.