Fine-tuning autophagy maximises lifespan and is associated with changes in mitochondrial gene expression in Drosophila

• Published in: PLoS genetics 2020-11, Vol.16 (11), p.e1009083-e1009083
• Main Authors: Bjedov, Ivana, Cochemé, Helena M, Foley, Andrea, Wieser, Daniela, Woodling, Nathaniel S, Castillo-Quan, Jorge Iván, Norvaisas, Povilas, Lujan, Celia, Regan, Jennifer C, Toivonen, Janne M, Murphy, Michael P, Thornton, Janet, Kinghorn, Kerri J, Neufeld, Thomas P, Cabreiro, Filipe, Partridge, Linda
• Format: Article
• Language: English
• Subjects: Aging; Aging (Biology); Aging - genetics; Animals; Autophagy; Autophagy (Cytology); Autophagy - genetics; Autophagy-Related Protein-1 Homolog - genetics; Autophagy-Related Protein-1 Homolog - metabolism; Biology and Life Sciences; Cell death; Cytological research; Drosophila; Drosophila melanogaster - genetics; Drosophila Proteins - genetics; Drosophila Proteins - metabolism; Gene expression; Gene Expression - genetics; Gene Expression Regulation - genetics; Genes, Mitochondrial - genetics; Genetic aspects; Genetic research; Homeostasis; Insects; Insulin; Insulin Receptor Substrate Proteins - genetics; Insulin Receptor Substrate Proteins - metabolism; Kinases; Life span; Life span (Biology); Longevity - genetics; Medicine and Health Sciences; Metabolism; Mitochondria; Mitochondria - genetics; Mitochondrial DNA; Phagocytosis; Physiological aspects; Protein Serine-Threonine Kinases - genetics; Proteins; Rapamycin; Receptor, Insulin - genetics; Signal Transduction; Spermidine
• ISSN: 1553-7404; 1553-7390; 1553-7404
• DOI: 10.1371/journal.pgen.1009083

Increased cellular degradation by autophagy is a feature of many interventions that delay ageing. We report here that increased autophagy is necessary for reduced insulin-like signalling (IIS) to extend lifespan in Drosophila and is sufficient on its own to increase lifespan. We first established that the well-characterised lifespan extension associated with deletion of the insulin receptor substrate chico was completely abrogated by downregulation of the essential autophagy gene Atg5. We next directly induced autophagy by over-expressing the major autophagy kinase Atg1 and found that a mild increase in autophagy extended lifespan. Interestingly, strong Atg1 up-regulation was detrimental to lifespan. Transcriptomic and metabolomic approaches identified specific signatures mediated by varying levels of autophagy in flies. Transcriptional upregulation of mitochondrial-related genes was the signature most specifically associated with mild Atg1 upregulation and extended lifespan, whereas short-lived flies, possessing strong Atg1 overexpression, showed reduced mitochondrial metabolism and up-regulated immune system pathways. Increased proteasomal activity and reduced triacylglycerol levels were features shared by both moderate and high Atg1 overexpression conditions. These contrasting effects of autophagy on ageing and differential metabolic profiles highlight the importance of fine-tuning autophagy levels to achieve optimal healthspan and disease prevention.