A genomic characterization of the response to sleep loss

Ut Southwestern Medical Center, Dallas TX

Investigators

Abstract

Sleep gates, or is permissive to, the resolution of sleep need. The resolution of sleep need reflects sleep function induced in response to waking (sleep homeostasis). Much is now known about the control of sleep/wake state expression and duration, but sleep function is less well understood. Significant differential expression of genes (DEG’s; 6000/13000 expressed in bulk tissue from frontal cortex; FC) in response to 6 hours of sleep deprivation (SD) has been observed. Of particular significance for CNS tissue, the sleep modulated gene ontology supports sleep control of neuronal excitability and transmission. Sleep dependent modulation of cellular function is likely to vary depending on different cell-type specific roles yet, little is understood about the cell-type specificity of sleep DEGs and their implications for biological intra- and inter-cellular pathways responsible for the SD response. Ado may be implicated as an inter- cellular (glia to neuron) mediator of sleep need since activation of its receptor, ADORA1 is required for sleep-homeostatic slow wave activity (SWA) but its role in sleep-related gene expression has not been examined. The following specific aims are proposed to characterize the genomic responses to sleep loss with respect to the cell-type specificity of DEGs and the pathways determining their SD response at an intercellular and intracellular level, in the mouse FC. 1.The differential expression of cell-type specific mRNA expression in response to sleep-loss will be compared to ad-libitum sleep condition and to recovery sleep condition to characterize the cell-type, specific and shared gene expression responses to sleep loss and recovery in FC tissue of C57 BL/6J mice. 2. Identification of cell-type specific open chromatin induced by sleep deprivation and sleep loss recovery will be made using ATACseq to identify potential enhancer and promoter sites important to the sleep loss response. 3. The role of Ado activation of ADORA1 receptors in the cell-type specific genomic response to sleep loss will be examined using a conditional Adora1 knockout that is unresponsive to Ado and a glial conditional Adk knockout with chronically elevated brain Ado and elevated SWA during waking and sleep. The first aim may provide fundamental insight into the cellular targets of sleep function with respect to cell-type specificity and differential genomic ontology in response to sleep loss. The second aim is designed to identify DNA loci as potential, cell type-specific, enhancer and/or promoter sites. Identification of these sites is important for characterization of genomic pathways activated by SD and further, is a first step towards understanding and prioritizing GWAS identified loci in non-coding DNA regions for future validation. The third aim will test Ado’s role as a mediator of the genomic changes observed in response to sleep loss and whether or not its mediation of homeostatic sleep SWA can be dissociated from the sleep loss transcriptome.