Over 10% of humans suffer chronic sleep disorders, but the genetic and neural mechanisms that regulate sleep are poorly understood. The identification of defective Hypocretin/Orexin (Hcrt) signaling as a cause of narcolepsy provided a genetic entry point into sleep research, but an effective treatment for this disorder has not yet been found. Moreover, only a small fraction of sleep disorders are associated with narcolepsy, indicating that additional genes and neurons that control sleep and wakefulness remain to be identified. The objective of this proposal is to use zebrafish as a simple and cost-effective vertebrate model system to study Hcrt signaling and sleep. Zebrafish are a useful model for these studies because they have the basic brain structures and genes that are thought to regulate mammalian sleep, but are also optically transparent and amenable to high-throughput behavior assays. The proposed research has three aims. First, we will characterize the development of larval zebrafish Hcrt neurons at the single neuron level and test hypotheses about their development. Second, we will use genetic and pharmacological approaches to determine which neurons are activated by Hcrt signaling and which neurotransmitter systems are required for Hcrt-induced wakefulness. Third, we will determine whether other sleep regulators, including adenosine, melatonin, and Kv3-type potassium channels, affect sleep via the Hcrt system. These experiments will improve our understanding of Hcrt neuron development and function, may provide clues to the basis of sleep disorders such as chronic insomnia, and may lead to novel therapies for these disorders.

Public Health Relevance

Over 10% of humans suffer chronic sleep disorders, but the causes of most of these disorders are unknown. This proposal will use zebrafish to examine how sleep is regulated by studying a gene whose loss causes the human sleep disorder narcolepsy and may be involved in other sleep disorders. The proposed studies will improve understanding of the genetic and neuronal mechanisms that regulate sleep and may suggest new strategies to treat sleep disorders.

National Institute of Health (NIH)
National Institute of Neurological Disorders and Stroke (NINDS)
Research Project (R01)
Project #
Application #
Study Section
Biological Rhythms and Sleep Study Section (BRS)
Program Officer
He, Janet
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
California Institute of Technology
Schools of Arts and Sciences
United States
Zip Code
Chiu, Cindy N; Rihel, Jason; Lee, Daniel A et al. (2016) A Zebrafish Genetic Screen Identifies Neuromedin U as a Regulator of Sleep/Wake States. Neuron 89:842-56
Chen, Audrey; Chiu, Cindy N; Mosser, Eric A et al. (2016) QRFP and Its Receptors Regulate Locomotor Activity and Sleep in Zebrafish. J Neurosci 36:1823-40
Chen, Shijia; Chiu, Cindy N; McArthur, Kimberly L et al. (2016) TRP channel mediated neuronal activation and ablation in freely behaving zebrafish. Nat Methods 13:147-50
Singh, Chanpreet; Oikonomou, Grigorios; Prober, David A (2015) Norepinephrine is required to promote wakefulness and for hypocretin-induced arousal in zebrafish. Elife 4:e07000
Gandhi, Avni V; Mosser, Eric A; Oikonomou, Grigorios et al. (2015) Melatonin is required for the circadian regulation of sleep. Neuron 85:1193-9
Liu, Justin; Merkle, Florian T; Gandhi, Avni V et al. (2015) Evolutionarily conserved regulation of hypocretin neuron specification by Lhx9. Development 142:1113-24
Chiu, Cindy N; Prober, David A (2013) Regulation of zebrafish sleep and arousal states: current and prospective approaches. Front Neural Circuits 7:58
Rossi, Paolo; Barbieri, Christopher M; Aramini, James M et al. (2013) Structures of apo- and ssDNA-bound YdbC from Lactococcus lactis uncover the function of protein domain family DUF2128 and expand the single-stranded DNA-binding domain proteome. Nucleic Acids Res 41:2756-68
Chen, Shijia; Oikonomou, Grigorios; Chiu, Cindy N et al. (2013) A large-scale in vivo analysis reveals that TALENs are significantly more mutagenic than ZFNs generated using context-dependent assembly. Nucleic Acids Res 41:2769-78