Aging is a degenerative process characterized by a progressive deterioration of cellular components and organelles resulting in mortality. The nematode Caenorhabditis elegans has been used extensively to study the biology of aging, and several determinants of C. elegans longevity are conserved in higher order organisms. The specific mechanisms of longevity in C. elegans have not been completely identified and many pathways are still poorly understood. Dietary restriction (DR) is one promising pro-longevity intervention, though its mechanism is poorly defined. DR, a reduction in caloric intake in the absence of malnutrition, extends lifespan in C. elegans and in a wide range of other species, including yeast, flies, mice, and primates. However this extension is highly dependent on genetic background. To investigate this, we are performing a genome-wide screen of the Vidal RNA interference (RNAi) Library, which has a catalog of 11,511 clones. By knocking down specific genes within the C. elegans genome through RNAi, we are able to observe an extension or reduction in longevity in response to DR. We have screened over 1500 genes; 61 of which are short-lived and 67 of which are long-lived. We are currently following up on our collected data by measuring the full lifespans using the RNAi clones that significantly shortened or extended lifespans in our screen. By screening such a large number of genes, the widespread effect, and hopefully mechanism, of DR will be elucidated. We hope to see genes significantly affected by DR cluster into groups with common functionality, or along the same pathway, and then follow up on those specific pathways to clarify the mechanisms underlying DR. If these pathways are conserved, research findings relating to C. elegans may be applicable to other organisms. We hope to confirm these results and further investigate the interaction between DR and other potential longevity pathways.

 Aging is a degenerative process characterized by a progressive deterioration of cellular components and organelles resulting in mortality. The nematode Caenorhabditis elegans has been used extensively to study the biology of aging, and several determinants of C. elegans longevity are conserved in higher order organisms. The specific mechanisms of longevity in C. elegans have not been completely identified and many pathways are still poorly understood. Dietary restriction is one promising pro-longevity intervention, though its mechanism is poorly defined. DR, a reduction in caloric intake in the absence of malnutrition, extends lifespan in C. elegans and in a wide range of other species, including yeast, flies, mice, and primates. However, this extension is highly dependent on genetic background. To investigate this, we are performing a genome-wide screen of the Vidal RNA interference (RNAi) Library, which has a catalog of 11,511 clones. By knocking down specific genes within the C. elegans genome through RNAi, we are able to observe an extension or reduction in longevity in response to DR. We have screened over 1500 genes, 61 of which are short-lived and 67 of which are long-lived. We are currently following up on our collected data by measuring the full lifespans using the RNAi clones that significantly shortened or extended lifespans in our screen. By screening such a large number of genes, the widespread effect, and hopefully mechanism, of DR will be elucidated. We hope to see genes significantly affected by DR cluster into groups with common functionality, or along the same pathway, and then follow up on those specific pathways to clarify the mechanisms underlying DR. If these pathways are conserved, research findings relating to C. elegans may be applicable to other organisms. We hope to confirm these results and further investigate the interaction between DR and other potential longevity pathways.

Ethosuximide is a succinimide anticonvulsant used in the clinical treatment of petit mal epileptic seizures in humans. Although its exact mechanism is not fully elucidated, it is believed to inhibit T-type calcium channels. In addition to its medical use, ethosuximide has been found to increase lifespan in the model organism, the nematode C. elegans. Nematodes exhibit lifespan extension when treated with ethosuximide at concentrations below a toxic threshold. While the published experimental results on ethosuximide-treated nematodes are promising, we have discovered that ethosuximide breaks down in the presence of 254 nm ultra-violet (UV) light, forming a toxic by-product. This change in ethosuximide that results in toxicity is specifically caused by irradiation, not heat. Acute exposure of C. elegans to ethosuximide treated with UV light results in death at lower dosages compared to nematodes treated with the control, native compound. UV-treated ethosuximide toxicity is independent of chemosensation (i.e. the sensing of chemical stimuli) as evidenced by the fact that chemosensory mutants do not show enhanced resistance to the UV-treated drug. Some human patients taking ethosuximide experience a butterfly rash under the eyes following exposure to sunlight. We speculate that this rash may be indicative of a similar mechanism of UV-induced cytotoxicity occurring in these patients. Taken together, these studies will help explicate the mechanism of toxicity resulting from exposure of ethosuximide to UV light, as well as the mechanism of action of native ethosuximide.