Starvation-induced sleep suppression requires the Drosophila brain nutrient sensor

Abstract

Animals increase their locomotion activity and reduce sleep duration under starved conditions. This suggests that sleep and metabolic status are closely interconnected. The nutrient and hunger sensors in the Drosophila brain, including diuretic hormone 44 (DH44)–, CN–, and cupcake-expressing neurons, detect circulating glucose levels in the internal milieu, regulate the insulin and glucagon secretion and promote food consumption. Food deprivation is known to reduce sleep duration, but a potential role mediated by the nutrient and hunger sensors in regulating sleep and locomotion activity remains unclear. Here, we show that DH44 neurons are involved in regulating starvation-induced sleep suppression, but CN neurons or cupcake neurons may not be involved in regulating starvation-induced sleep suppression or baseline sleep patterns. Inactivation of DH44 neurons resulted in normal daily sleep durations and patterns under fed conditions, whereas it ablated sleep reduction under starved conditions. Inactivation of CN neurons or cupcake neurons, which were proposed to be nutrient and hunger sensors in the fly brain, did not affect sleep patterns under both fed and starved conditions. We propose that the glucose-sensing DH44 neurons play an important role in mediating starvation-induced sleep reduction.

Keywords:

• DH44
• starvation-induced sleep loss
• Drosophila
• nutrient sensors

Acknowledgements

We thank Dr. Young-Joon Kim for providing anti-DH44 antibody used in this study, and the Oh lab and Suh lab members for stimulating discussion and critical reading of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Ewha Womans University Research Grant (1-2022-0352-001-1), the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (No. RS-2023-00212599) to Y.O. This work is also supported by a Samsung Science and Technology Foundation grant (SSTF-BA-1802-11), the National Research Foundation of Korea (NRF-2020R1A2C2009865), and the KAIST Chancellor's fund to G.S.B.S.