Increasing glucose uptake into neurons antagonizes brain aging and promotes health and life span under dietary restriction in Drosophila

Abstract

Brain neurons play a central role in organismal aging, but there is conflicting evidence about the roles of neuronal glucose availability, glucose uptake and metabolism in aging and extended lifespan. Here, we analyzed metabolic changes in the brain neurons of Drosophila during aging. Using a genetically-encoded fluorescent ATP biosensor, we found decreased ATP concentration in the neuronal somata of aged flies, which was correlated with decreased glucose content, expression of glucose transporter and glycolytic enzymes and mitochondrial quality. The age-associated reduction in ATP concentration did not occur in brain neurons with suppressed glycolysis or enhanced glucose uptake, suggesting these pathways contribute to reductions in ATP. Despite age-associated mitochondrial damage, increasing glucose uptake maintained ATP levels, suppressed age-dependent locomotor deficits and extended the life span. Increasing neuronal glucose uptake during dietary restriction resulted in the longest lifespans, suggesting an additive effect of enhancing glucose availability during a bioenergetic challenge on aging.