Project Summary Today, we live in an age of unprecedented access to food. Recent research suggests that many Americans eat from the time they wake up to the time they go to sleep. Night eating, specifically, is linked to several aging- related comorbidities, including obesity, cardiovascular disease, and type-2 diabetes. While much ongoing research investigates the mechanisms by which dietary components affect metabolism, it is less understood how the timing of feeding affects metabolism. To this end, dietary interventions that alter the timing of feeding have been shown to protect many aspects of health, even without reducing caloric intake. Time-restricted feeding (TRF) diets have been shown in mice and humans to reduce oxidative stress and inflammation, decrease insulin resistance, lower blood sugar. In mice, TRF has been shown to reduce fat levels, protect against a high-fat diet, and prevent obesity. Using Drosophila melanogaster, the Shirasu-Hiza lab developed a robust TRF diet that extends lifespan and delays molecular signs of aging, such as protein aggregation, and showed that TRF enhances circadian gene expression and requires the circadian clock to confer lifespan benefits. In addition, we found that TRF seems to reprogram lipid metabolism; after TRF treatment, flies responded to fasting by utilizing lipids much faster than controls, leading to increased rate of triacylglyceride loss and starvation sensitivity. I found that this TRF-accelerated lipid usage, like TRF-induced lifespan extension, requires circadian components but, unlike TRF-induced lifespan extension, does not require autophagy components. Because the underlying mechanisms remain unclear, I propose to identify molecular components that drive the effects of TRF on lipid metabolism. I will use Drosophila melanogaster, an advantageous model organism for this work because: many mammalian metabolic pathways are conserved in flies; flies have short generation time (2-3 months); and flies offer a plethora of powerful genetic tools. Aim 1 will identify specific tissue(s) in which circadian regulators are required for TRF-accelerated lipid usage. Aim 2 will examine the molecular mechanisms by which TRF changes lipid metabolism. I will use RNA-sequencing analysis to identify transcriptional differences between TRF-treated flies and their controls; significantly differentially expressed genes and/or pathways will be assessed for their functional role in TRF-accelerated lipid usage. Aim 3 will investigate the therapeutic potential of TRF in diet- induced obesity. Flies fed a high-sugar diet and have hallmarks of obesity will be treated with TRF to test if obesity-related phenotypes are ameliorated upon TRF treatment; we will test both young and old flies. These experiments will determine the molecular mechanisms connecting TRF to lipid metabolism and how TRF can be used to ameliorate obesity- and aging-related pathologies. This will improve our understanding on how TRF can confer he...