Investigation of Potential Caloric Restriction in a Long-Lived C.Elegans Mutant, inx-16

Science Center, Bent Corridor

Humans have long sought the secret to long life. In our lab, we investigate factors affecting aging in Caenorhabditis elegans (C. elegans), a small nematode with short lifespan and powerful genetics. In a wide array of animals, lower caloric intake leads to enhanced lifespan. Lower feeding results in metabolic alterations that shift energy use away from reproductive processes and into self-preservation. In C. elegans, caloric restriction induces delayed development, reduced body size, fewer progeny, and longer lifespan. We have a mutant that displays many of the caloric restriction traits. This mutant lacks a component of an intestinal gap junction called innexin-16. We are investigating whether this mutant has caloric restriction at the physiologic and molecular level. We hypothesize that the innexin-16 mutant is calorically restricted due to a defect in nutrient absorption. We have been able to isolate the step in digestion likely affected in the mutant. The animals’ ingestion rates were investigated using a functional measure of the organ analogous to the human mouth and stomach, the C. elegans pharynx. innexin-16 mutants have normal food intake in this assay. Yet these animals seem to be deficient in body fat. inx-16 mutants have less body fat storage than wildtype as indicated by a body fat staining procedure. Our results are consistent with inx-16 mutants being incapable of properly absorbing the nutrients they ingest. We suspect this is due to an intestinal defect and are currently developing tools to investigate this possibility.