The flavonoid isoliquiritigenin promotes lifespan extension of Caenorhabditis elegans through the transcription factor DAF-16 and aquaporin-2.

Aging is associated with the accumulation of oxidative damage. Isoliquiritigenin (ISL), a natural flavonoid, exhibits antioxidant properties, but its effect on lifespan and the underlying mechanisms remains incompletely understood. This study aimed to investigate whether ISL extends lifespan in Caenorhabditis elegans through the transcription factor DAF-16 and the aquaporin AQP-2. We employed lifespan assays, stress resistance tests, intracellular ROS measurement, osmotic water permeability assays in Xenopus oocytes, genetic manipulation (using mutants and RNAi), quantitative real-time PCR, and fluorescence microscopy to assess DAF-16 localization and target gene expression. ISL extended the mean lifespan of wild-type C. elegans by 15.35% at 20 μM (P<0.01). It enhanced resistance to oxidative stress (36.54% higher survival under paraquat) and heat shock (20.56% higher survival at 37°C), and reduced intracellular ROS levels. Mechanistically, ISL increased DAF-16 nuclear translocation by 44.3% (P=0.003), and upregulated the expression of its target genes, including sod-3 (3.2-fold, P=0.008) and aqp-2 (2.9-fold, P=0.012). ISL also increased the osmotic water permeability of Xenopus oocytes by 1.7-fold (P=0.007), and the effect was abolished by the aquaporin inhibitor HgCl2. Genetic ablation of aqp-2 nullified ISL-induced lifespan extension (P=0.65 vs control) and ROS reduction. Crucially, aqp-2 RNAi suppressed ISL-driven DAF-16 nuclear accumulation and sod-3 expression, establishing a feedforward loop. ISL extended lifespan and enhanced stress resistance in C. elegans by activating a DAF-16/AQP-2 regulatory module, thereby linking water homeostasis to the transcriptional control of aging.