Interaction between sleep and the immune response in Drosophila: a role for the NFkappaB relish.
OBJECTIVE
The regulation of sleep is poorly understood. While some molecules, including those involved in inflammatory/immune responses, have been implicated in the control of sleep, their role in this process remains unclear. The Drosophila model for sleep provides a powerful system to identify and test the role of sleep-relevant molecules.


METHODS
We conducted an unbiased screen for molecular candidates involved in sleep regulation by analyzing genome-wide changes in gene expression associated with sleep deprivation in Drosophila. To further examine a role of immune-related genes identified in the screen, we performed molecular assays, analysis of sleep behavior in relevant mutant and transgenic flies, and quantitative analysis of the immune response following sleep deprivation.


RESULTS
A major class of genes that increased expression with sleep deprivation was that involved in the immune response. We found that immune genes were also upregulated during baseline conditions in the cyc01 sleep mutant. Since the expression of an NFkappaB, Relish, a central player in the inflammatory response, was increased with all manipulations that reduced sleep, we focused on this gene. Flies deficient in, but not lacking, Relish expression exhibited reduced levels of nighttime sleep, supporting a role for Relish in the control of sleep. This mutant phenotype was rescued by expression of a Relish transgene in fat bodies, which are the major site of inflammatory responses in Drosophila. Finally, sleep deprivation also affected the immune response, such that flies deprived of sleep for several hours were more resistant to bacterial infection than those flies not deprived of sleep.


CONCLUSIONS
These results demonstrate a conserved interaction between sleep and the immune system. Genetic manipulation of an immune component alters sleep, and likewise, acute sleep deprivation alters the immune response.
Williams
Julie A
JA
Center for Advanced Biotechnology and Medicine and Department of Pharmacology, University of Medicine and Dentistry of New Jersey, Piscataway 08854-5603, USA. jwilliams@cabm.rutgers.edu
Sathyanarayanan
Sriram
S
Hendricks
Joan C
JC
Sehgal
Amita
A
D056930:ARNTL Transcription Factors; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics; D004252:DNA Mutational Analysis; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics*; D015870:Gene Expression / Q000502:physiology; D005802:Genes, MHC Class II / Q000235:genetics* / Q000276:immunology; D006706:Homeostasis / Q000235:genetics / Q000276:immunology; D018836:Inflammation Mediators / Q000502:physiology; D012890:Sleep / Q000235:genetics* / Q000276:immunology*; D012892:Sleep Deprivation / Q000235:genetics / Q000276:immunology; D014157:Transcription Factors / Q000235:genetics*; D015854:Up-Regulation / Q000502:physiology
D056930:ARNTL Transcription Factors; D051792:Basic Helix-Loop-Helix Proteins; D029721:Drosophila Proteins; D018836:Inflammation Mediators; D014157:Transcription Factors; C101626:Rel protein, Drosophila; C112805:cyc protein, Drosophila