Brain Transcriptomics Across Diverse Sleep-Wake Manipulations Reveals Multiple Homeostatic Pathways in Drosophila.

Area of Science:

• Neuroscience
• Genetics
• Chronobiology

Background:

• Sleep is regulated by circadian and homeostatic processes.
• The period (per) gene is a key regulator of the circadian clock in Drosophila.
• The molecular basis of sleep homeostasis is less understood.

Purpose of the Study:

• To identify "sleeper" genes in Drosophila brain whose expression correlates with sleep-wake history.
• To investigate the molecular underpinnings of sleep homeostasis.

Main Methods:

• Transcriptomic analysis of Drosophila brain under various sleep-wake manipulation conditions (mechanical, thermogenetic, optogenetic, pharmacological).
• Analysis of 7 datasets to identify genes consistently changing with sleep-wake history.
• Utilized a GPT-based algorithm (fl.ai) to identify sleep-wake regulated genes with known functions.

Main Results:

• No single gene was sleep-wake dependent across all datasets, suggesting method-specific effects.
• Identified genes involved in mitochondrial oxidative phosphorylation and ribosome biogenesis.
• Found genes correlated with recent (<3h) and longer (>6h) sleep history, indicating temporally distinct pathways.
• Identified sleep-wake regulated genes involved in immunity, neuropeptide signaling, glucose transport, and neuronal excitability.

Conclusions:

• Sleep homeostasis appears to be a more molecularly distributed process than the core circadian clock.
• Multiple pathways, including novel ones like ribosome biogenesis, contribute to sleep homeostasis.
• Distinct temporal integration of waking experience influences gene expression related to sleep.