Abstract
High carbohydrate intake, a characteristic of many Western diets, is a major contributor to age-associated pathologies. Here, we explored the molecular consequences of sugar overload during chronological aging in the yeast Saccharomyces cerevisiae. High levels of glucose and fructose resulted in a decrease of chronological lifespan as well as an increase of cell death, ROS and neutral lipids. Interestingly, these changes were accompanied by significantly altered ceramide profiles. Deletion of either the kinase Tor1, a master regulator of growth and autophagy in response to nutrients, or the vacuole-anchored receptor Vac8, an important player in various autophagy pathways, improved survival and normalized ceramide profiles. This suggests that ceramides might play a role in sugar stress-induced cell death. In line, pharmacological inhibition of sphingolipid synthesis normalized ceramide profiles and improved chronological lifespan, whereas pharmacologically induced ceramide accumulation decreased chronological lifespan. In sum, our findings causally link nutrient signaling and an altered ceramide profile to sugar cytotoxicity in aging yeast, providing a basis for further search of feasible interventions against sugar-induced cell death.