Age-Related Increase in Lactate Dehydrogenase Activity in Skeletal Muscle Reduces Life Span in<i>Drosophila</i>
Liam C. Hunt, Fabio Demontis
Abstract
Metabolic adaptations occur with aging but the significance and causal roles of such changes are only partially known. In Drosophila, we find that skeletal muscle aging is paradoxically characterized by increased readouts of glycolysis (lactate, NADH/NAD+) but reduced expression of most glycolytic enzymes. This conundrum is explained by lactate dehydrogenase (LDH), an enzyme necessary for anaerobic glycolysis and whose expression increases with aging. Experimental Ldh overexpression in skeletal muscle of young flies increases glycolysis and shortens life span, suggesting that age-related increases in muscle LDH contribute to mortality. Similar results are also found with overexpression of other glycolytic enzymes (Pfrx/PFKFB, Pgi/GPI). Conversely, hypomorphic mutations in Ldh extend life span, whereas reduction in PFK, Pglym78/PGAM, Pgi/GPI, and Ald/ALDO levels shorten life span to various degrees, indicating that glycolysis needs to be tightly controlled for optimal aging. Altogether, these findings indicate a role for muscle LDH and glycolysis in aging.