Exploring Acetyl-CoA-Mediated Beta-Hydroxybutyrate Enrichment in Yeast: A Mechanistic Link to Longevity

Abstract Aging predisposes organisms to diseases ranging from diabetes to Alzheimer’s, driving interest in interventions like Caloric Restriction (CR), which extends lifespan across species. While CR’s benefits are well-documented, its metabolic mechanisms remain incompletely understood. This study investigates β-hydroxybutyrate (βHB), a ketone body, in CR-mediated longevity using Saccharomyces cerevisiae. Despite the absence of canonical ketogenesis enzymes (HMG-CoA lyase, OXCT1) in yeast, we detect βHB for the first time in stationary-phase and CR conditions via metabolomics, GC-MS, and luminescence assays. Alternative carbon sources and supplementing yeast media with acetoacetate drive βHB levels. In addition, we identify mitochondrial acetyl-CoA metabolism (ACS1) and mtFAS pathways to be critical for βHB enrichment during CR. βHB supplementation extends chronological lifespan dose-dependently, mirroring CR’s effects, and combined CR + βHB yields additive lifespan extension. Transcriptomic profiling reveals 156 overlapping genes and 268 βHB-exclusive targets, suggesting shared (TCA cycle, amino acid metabolism) and βHB-specific mechanisms (mitochondrial translation, stress response). These findings resolve yeast’s unexpected capacity for ketogenesis and establish it as a model for dissecting βHB’s role in aging. This work also elucidates conserved nodes linking ketogenesis to longevity and positions yeast as a platform for exploring CR-mimicking therapeutics.