.-The functions of sleep and what controls it remain unanswered biological questions. According to the two-process model, a circadian process and a homeostatic process interact to regulate sleep. While progress has been made in understanding the molecular and cellular functions of the circadian process, the mechanisms of the homeostatic process remain undiscovered. We use the recently established sleep model system organism Drosophila melanogaster to examine dynamic changes in gene expression during sleep and during prolonged wakefulness in the brain. Our experimental design controls for circadian processes by killing animals at three matched time points from the beginning of the consolidated rest period [Zeitgeber time (ZT) 14)] under two conditions, sleep deprived and spontaneously sleeping. Using ANOVA at a false discovery rate of 5%, we have identified 252 genes that were differentially expressed between sleep-deprived and control groups in the Drosophila brain. Using linear trends analysis, we have separated the significant differentially expressed genes into nine temporal expression patterns relative to a common anchor point (ZT 14). The most common expression pattern is a decrease during extended wakefulness but no change during spontaneous sleep (n ϭ 114). Genes in this category were involved in protein production (n ϭ 47), calcium homeostasis, and membrane excitability (n ϭ 5). Multiple mechanisms, therefore, act to limit wakefulness. In addition, by studying the effects of the mechanical stimulus used in our deprivation studies during the period when the animals are predominantly active, we provide evidence for a previously unappreciated role for the Drosophila immune system in the brain response to stress. sleep deprivation; temporal regulation; stress SLEEP HAS BEEN OBSERVED in animal species ranging from insects to humans. We know that total sleep deprivation results in animal death (3,69,70), but the biological function of sleep remains poorly understood. With a rising prevalence of sleep restriction in our society (2, 6, 26), it becomes increasingly important to understand the function and regulation of sleep as well as the consequences of sleep deprivation on the brain.A popular conceptual framework to understand the regulation of sleep is called the two-process model. According to this model, a circadian process and a sleep-promoting (homeostatic) process, which are mechanistically distinct, interact to regulate sleep (7,8). While the cellular and molecular basis for the circadian process has been largely delineated, the homeostatic process remains poorly understood. A key feature of the homeostatic process is that the drive for sleep is proportional to the prior duration of wakefulness and that the restorative function of sleep is related to sleep time. Therefore, to understand the molecular underpinnings of the homeostatic process, wakefulness and sleep cannot be treated as single static behavioral states but, rather, as dynamic processes.To gain insight into the dynamic molecular processes th...

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One function of sleep is thought to be the restoration of energy stores in the brain depleted during wakefulness. One such energy store found in mammalian brains is glycogen. Many of the genes involved in glycogen regulation in mammals have also been found in Drosophila melanogaster and rest behavior in Drosophila has recently been shown to have the characteristics of sleep. We therefore examined, in the fly, variation in the glycogen contents of the brain, the whole head and the body throughout the rest/activity cycle and after rest deprivation. Glycogen in the brain varies significantly throughout the day (p ¼ 0.001) and is highest during rest and lowest while flies are active. Glycogen levels in the whole head and body do not show diurnal variation. Brain glycogen drops significantly when flies are rest deprived for 3 h (p ¼ 0.034) but no significant differences are observed after 6 h of rest deprivation. In contrast, glycogen is significantly depleted in the body after both 3 and 6 h of rest deprivation (p < 0.0001 and p < 0.0001, respectively). Glycogen in the fly brain changes in relationship to rest and activity and demonstrates a biphasic response to rest deprivation similar to that observed in mammalian astrocytes in culture.

Colorectal cancer (CRC) is the second leading cause of cancerrelated death in the United States. In 2017, ~100 000 patients are expected to be diagnosed with local (stages 0-II) or regional (stage III) CRC where prognostic information is needed to guide patient management. 1 Unfortunately, current histopathologic staging methods are imperfect and considerable stage-independent variability exists in clinical outcome. The role of adjuvant chemotherapy in stage II patients remains unresolved, 2-9 and it is estimated that one-third of such patients receive adjuvant chemotherapy in the United States. Accordingly, a substantial proportion of patients are currently overtreated and a high-risk subset is undertreated. 10 Acknowledging the limitations of stage-specific treatment guidelines, there remains an unmet need for more accurate prognostic tools to identify stage II patients at risk of relapse that are likely to benefit from adjuvant chemotherapy. 11 Prognostic test development is predicated on the identification of novel biomarkers associated with tumor recurrence/ metastasis. Actin-binding proteins such as the vasodilatorstimulated phosphoprotein (VASP) represent promising biomarker targets with potential prognostic utility. 12-15 VASP is an actin polymerase that directs the formation of migratory and invasive membrane structures including filopodia and invadopodia. 12 ABSTRACT BACkgRound And AIMS:The benefit of adjuvant chemotherapy for stage II colorectal cancer (CRC) patients remains unclear, emphasizing the need for improved prognostic biomarkers to identify patients at risk of metastatic recurrence. To address this unmet clinical need, we examined the expression and phosphorylation status of the vasodilator-stimulated phosphoprotein (VASP) in CRC tumor progression. VASP, a processive actin polymerase, promotes the formation of invasive membrane structures leading to extracellular matrix remodeling and tumor invasion. Phosphorylation of VASP serine (Ser) residues 157 and 239 regulate VASP function, directing subcellular localization and inhibiting actin polymerization, respectively.