Sleep controls peroxisomal abundance to reduce wake-induced brain oxidation

Abstract

Sleep is increasingly linked to the regulation of Reactive Oxygen Species (ROS) and lipid metabolism. However, the mechanisms underlying this interaction are underexplored. Here, we use Drosophila melanogaster to report a bidirectional relationship between sleep and peroxisomes, cellular organelles that process lipids and alleviate ROS. Of the genes that change expression after sleep deprivation in the dorsal fan-shaped body, knockdown of the peroxisomal biogenesis factor Pex16 results in decreased sleep. Pex16 acts in several brain regions to modulate sleep amount, with ellipsoid body neurons (EB) producing the highest sleep reduction of the sleep-promoting regions. Consistent with a general role for peroxisomes, knockdown of other peroxisomal enzymes relevant for lipid import and synthesis also decreases sleep. Whole-brain peroxisomal numbers increase with wake, which is supported by lipidomic analysis indicating that peroxisomal-derived phospholipids are the major contributors to phospholipid changes after wake or sleep deprivation. Peroxisomal proliferation in the EB is driven by neuronal activity and increased oxidation, suggesting that these mediate the effect of wake/sleep loss. In turn, peroxisomes alleviate the oxidation accumulated during wake, such that loss of Pex16 in the EB works non-cell autonomously to increase lipid peroxidation brain-wide. This likely contributes to sleep loss, as sleep is rescued with an antioxidant. Together, these results position peroxisomes as key players in sleep, regulating ROS and thereby maintaining normal cycles.