Characterization of Stress Responses in a Drosophila Model of Werner Syndrome.

As organisms age, their resistance to stress decreases while their risk of disease increases. This can be shown in patients with Werner syndrome (WS), which is a genetic disease characterized by accelerated aging along with increased risk of cancer and metabolic disease. WS is caused by mutations in WRN , a gene involved in DNA replication and repair. Recent research has shown that WRN mutations contribute to multiple hallmarks of aging including genomic instability, telomere attrition, and mitochondrial dysfunction. However, questions remain regarding the onset and effect of stress on early aging. We used a fly model of WS ( WRNexo Δ ) to investigate stress response during different life stages and found that stress sensitivity varies according to age and stressor. While larvae and young WRNexo Δ adults are not sensitive to exogenous oxidative stress, high antioxidant activity suggests high levels of endogenous oxidative stress. WRNexo Δ adults are sensitive to stress caused by elevated temperature and starvation suggesting abnormalities in energy storage and a possible link to metabolic dysfunction in WS patients. We also observed higher levels of sleep in aged WRNexo Δ adults suggesting an additional adaptive mechanism to protect against age-related stress. We suggest that stress response in WRNexo Δ is multifaceted and evokes a systemic physiological response to protect against cellular damage. These data further validate WRNexo Δ flies as a WS model with which to study mechanisms of early aging and provide a foundation for development of treatments for WS and similar diseases.