Transcriptional dynamics of sleep deprivation and subsequent recovery sleep in the male mouse cortex.

Sleep is an essential, tightly regulated biological function. Sleep is also a homeostatic process, with the need to sleep increasing as a function of being awake. Acute sleep deprivation (SD) increases sleep need, and subsequent recovery sleep (RS) discharges it. SD is known to alter brain gene expression in rodents, but it remains unclear which changes are linked to sleep homeostasis. To investigate this question, we analyzed RNA-seq data from adult male mice subjected to 3 and 5-6 h of SD and 2 and 6 h of subsequent RS. We hypothesized that molecular changes associated with sleep homeostasis would mirror sleep pressure dynamics as defined by brain electrical activity, peaking at 5-6 h of SD and no longer differentially expressed after 2 h of RS. We report that 5-6 h of SD produces the largest effect on gene expression, and the majority of differentially expressed genes normalize after 2 h of RS. These genes are involved in cellular redox homeostasis, DNA damage/repair, and chromatin regulation and may underlie the molecular basis of sleep homeostasis. Genes associated with cellular stress do not normalize within 6 h of RS and may underlie non-sleep-specific effects of SD. In addition, RS affects gene expression related to energy metabolism and Wnt-signaling, potentially contributing to its restorative effects. Finally, our study also points to the regulation of expression of a subset of circadian transcription factors as a function of sleep need. Overall, our results offer novel insights into the molecular mechanisms underlying sleep homeostasis and the broader effects of SD.