David M. Raizen
David M. Raizen, MD, PhD
462 Stemmler Hall
415 Curie Blvd
Philadelphia, PA 19104-4283
University of Texas at Austin, 1989.
University of Texas Southwestern, 1997.
University of Texas Southwestern, 1997.
Description of Research ExpertiseResearch Interests
The regulation and function of sleep
Key Words: sleep, ecdysis, molting, behavior, amyloid, neuropeptides
Description of Research
Quiescent behavioral states are universal to the animal world with the most famous and mysterious of these being sleep. Despite the fact that we spend one third of our life sleeping, and despite the fact that all animals sleep, the core function of sleep remains a mystery. In addition, the molecular basis underlying sleep/wake regulation is poorly understood.
We use C. elegans as a model system to address these questions. C. elegans offers many experimental advantages including powerful genetic tools as well as a simple neuroanatomy.
Growth of C. elegans from an embryo to an adult is punctuated by four molts, during which the animal secretes a new cuticle and sheds its old one. Prior to each molt the worm has a quiescent behavioral state called lethargus. Lethargus has several similarities to sleep including rapid reversibility to strong stimulation, increased sensory arousal threshold, and homeostatic regulation.
In addition to larval sleep, C. elegans also sleeps during the adult stage, after exposure to an environment that induces cellular stress.
Molecular genetic similarity between C. elegans sleep and sleep in other animals is demonstrated by the identification of signaling pathways that regulate C. elegans sleep in the similar fashion to their regulation of sleep in mammals and arthropods. We have identified new sleep regulators in C. elegans and are currently studying how and in which cells these regulators function.
By studying the purpose and genetic regulation of nematode sleep, we hope to identify additional novel sleep regulators, and to gain insight into why sleep had evolved, a central biological mystery.
Please see David about possible projects.
Description of Clinical ExpertiseSleep disorders: In particular disorders of sleep regulation and restless leg syndrome.
Selected PublicationsLenz O, Xiong J, Nelson MD, Raizen, DM, Williams JA: FMRFamide signaling promotes stress-induced sleep in Drosophila. Brain Behavior and Immunity (Impact factor 6.1) in press, 2015.
George-Raizen JB, Shockley KR, Trojanowski NF, Lamb AL, and Raizen DM: Dynamically-expressed prion-like proteins form a cuticle in the pharynx of Caenorhabditis elegans. Biology Open 3(11): 1139-1149, November 2014. Notes: Article featured on the journal cover.
Nelson MD, Lee KH, Churgin MA, Hill AJ, Van Buskirk C, Fang-Yen C,and Raizen DM: FMRFamide-like FLP-13 neuropeptides promote quiescence following heat stress in Caenorhabditis elegans. Current Biology (Impact factor 9.9) 24(20): 2406-2410, October 2014. Notes: Article discussed in Nature Neuroscience Reviews.
Hill AJ, Mansfield R, Lopez JMNG, Raizen DM,and Van Buskirk C: Cellular Stress Induces a Protective Sleep-like State in C. elegans. Current Biology (Impact factor 9.9) 24(20): 2399-2405, October 2014. Notes: Article discussed in Nature Neuroscience Reviews).
Nagy S, Raizen DM*, Biron D. : Measurements of behavioral quiescence in Caenorhabditis elegans. Methods (Impact factor 3.2) 68(3): 500-507, August 2014. Notes: *Corresponding Author.
Trojanowski NF, Padovan-Merhar O, Raizen DM*, Fang-Yen C. : Neural and genetic degeneracy underlies Caenorhabditis elegans feeding behavior. J Neurophysiol (Impact factor 3.0) 112(4): 951-61, May 2014. Notes: *Corresponding author.
Davis EM and Raizen DM: Prolonging apneas in a hospitalized patient – a potential harm of routine medical therapy. Annals of the American Thoracic Society 11(9): 1500-1503, Nov 2014.
Ryu MH, Kang IH, Nelson MD, Jensen TM, Lyuksyutova AI, Siltberg-Liberles J, Raizen DM, Gomelsky M.: Engineering adenylate cyclases regulated by near-infrared window light. Proc Natl Acad Sci U S A. (Impact factor 9.8) 111(28): 10167-72, July 2014.
Yuan J, Raizen DM, Bau HH.: Gait synchronization in Caenorhabditis elegans. Proc Natl Acad Sci U S A. (Impact factor 9.8) 111(19): 6865-70, May 2014.
Yu CC, Raizen DM, Fang-Yen C: Multi-well imaging of development and behavior in Caenorhabditis elegans. Journal of Neuroscience Methods (Impact factor 2.0) 223: 35-39, February 2014.