From DNA Damage to Sleep: Unraveling the Sleep Homeostat in Drosophila

While sleep is an evolutionarily conserved behavior, and different hypotheses have been proposed to explain its homeostatic function, establishing a universal hypothesis remains an active field of research. A recent hypothesis suggests sleep is essential to repair neuronal DNA damage accumulated during wakefulness. This is critical, since post-mitotic neurons require lifetime genome maintenance and produce high levels of reactive oxygen species. We investigate this mechanism using Drosophila melanogaster. First, we observed that sleep deprivation (SD) causes DNA damage accumulation—evidenced by increased gamma-H2Av nuclear foci in confocal imaging—which is reversible upon recovery. Additionally, we conducted a regional analysis of the brain to assess the vulnerability of specific areas to SD-induced damage. To test causality, we utilized the TrpA1 thermogenetic channel to experimentally induce DNA damage in targeted neuronal subpopulations. By evaluating behavioral dynamics over varying activation times, we demonstrated this manipulation significantly increases sleep pressure, measured via DAMs and Ethoscopes. Furthermore, we assessed motor health using climbing assays to rule out generalized motor impairment. As ongoing work, we are standardizing flow cytometry validations and implementing an inducible CRISPR system to trigger acute DNA damage in adults. Our ultimate goal is to determine if DNA damage and its subsequent repair are integral components of the sleep homeostat.