Enhancing autophagy by redox regulation extends lifespan in Drosophila.

Dysregulation of redox homeostasis is implicated in the ageing process and the pathology of age-related diseases. To study redox signalling by H(2)O(2) in vivo, we established a redox-shifted model by manipulating levels of the H(2)O(2)-degrading enzyme catalase in Drosophila. Here we report that ubiquitous over-expression of catalase robustly extends lifespan in females. As anticipated, these flies are strongly resistant to a range of oxidative stress challenges, but interestingly are sensitive to starvation, which could not be explained by differences in levels of energy reserves. This led us to explore the contribution of autophagy, which is an important mechanism for organismal survival in response to starvation. We show that autophagy is essential for the increased lifespan by catalase upregulation, as the survival benefits are completely abolished upon global autophagy knock-down. Furthermore, using a specific redox-inactive knock-in mutant, we highlight the in vivo role of a key regulatory cysteine residue in Atg4a, which is required for the lifespan extension in our catalase model. Altogether, these findings confirm the redox regulation of autophagy in vivo as an important modulator of longevity.