Effect of vitamin D₃ on lifespan in Caenorhabditis elegans

Vitamin D is an essential micronutrient, necessary for human health. To determine if Caenorhabditis elegans (C. elegans) could function as an effective model to study the mechanisms of action of vitamin D, we asked if vitamin D₃ affects C. elegans lifespan. Multiple factors positively impact lifespan in this system including dietary restriction and vitamin E. In addition, the C. elegans DAF-12 nuclear hormone receptor is homologous to the vitamin D receptor in humans and is therefore a candidate for a functional vitamin D receptor. It was hypothesized that vitamin D₃ supplementation would increase the lifespan of C. elegans in a DAF-12-dependent manner. Dose-response curves were completed, and results indicate that exposure to 1,000 μg/ml vitamin D₃ significantly increased the lifespan of wild-type worms by up to 39% (p<0.001). The daf-12 mutants exposed to 1,000 μg/ml vitamin D₃ lived significantly longer than daf-12 controls exposed to 0 μg/ml (p<0.001), but among worms exposed to 1,000 μg/ml vitamin D₃, wild type lived significantly longer than daf-12 (p<0.01). The data suggest that vitamin D₃ can interact with multiple receptors, possibly implicating the NHR family of nuclear hormone receptors related to DAF-12. This research is the first to our knowledge to utilize C. elegans as a model to study the impact of vitamin D₃ on longevity and supports the use of this model system to increase our understanding of vitamin D function at the cellular level, its role in cellular health, and its potential medicinal utility in humans.