David M. Raizen, MD, PhD

faculty photo
Assistant Professor of Neurology
Department: Neurology
Graduate Group Affiliations

Contact information
Dept Neurology
462 Stemmler Hall
415 Curie Blvd
Philadelphia, PA 19104-4283
Education:
BA (Biochemistry)
University of Texas at Austin, 1989.
PhD (Neuroscience)
University of Texas Southwestern, 1997.
MD (Medicine)
University of Texas Southwestern, 1997.
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Description of Research Expertise

Research 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 appear to 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 homeostasis, which is manifested by an increased depth of sleep following a period of deprivation. Similarity to sleep at the molecular genetic level is demonstrated by the identification of signaling pathways that regulate C. elegans lethargus in the similar fashion to their regulation of sleep in mammals and arthropods. For examples, cAMP signaling promotes wakefulness and epidermal growth factor signaling promotes sleep in C. elegans and other organisms. We have identified new regulators of sleep like behavior in C. elegans and are currently studying how these regulators function to regulate sleep.

By studying the purpose and genetic regulation of nematode lethargus, we hope to identify additional novel sleep regulators, and to gain insight into why sleep and sleep-like states had evolved, a central biological mystery.

Rotation projects
Please see David about possible projects.

Selected Publications

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 in press, September 2014.

Nagy S, Raizen* DM, Biron D. *Corresponding Author: Measurements of behavioral quiescence in Caenorhabditis elegans. Methods Epub ahead of print, August 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. 111(28): 10167-72, July 2014.

Yuan J, Raizen DM, Bau HH.: Gait synchronization in Caenorhabditis elegans. Proc Natl Acad Sci U S A. 111(19): 6865-70, May 2014.

Trojanowski NF, Padovan-Merhar O, Raizen DM*, Fang-Yen C. *Corresponding author: Neural and genetic degeneracy underlies Caenorhabditis elegans feeding behavior. J Neurophysiol 112(4): 951-61, May 2014.

Yu CC, Raizen DM, Fang-Yen C: Multi-well imaging of development and behavior in Caenorhabditis elegans. Journal of Neuroscience Methods 223: 35-39, February 2014.

Davis EM and Raizen DM: Prolonging apneas in a hospitalized patient – a potential harm of routine medical therapy. Annals of the American Thoracic Society in press, 2014.

Julia B. George-Raizen, Keith R. Shockley, Nicholas F. Trojanowski, Annesia L. Lamb, and David M. Raizen: Dynamically-expressed prion-like proteins form a cuticle in the pharynx of Caenorhabditis elegans. Biology Open in press, 2014.

Hill1 AJ,Mansfield R, Lopez JMNG, Raizen DM,and Van Buskirk C: Cellular Stress Induces a Protective Sleep-like State in C. elegans. Current Biology in press, 25264259 2014.

Belfer SJ,Chuang HS, Freedman BL, Yuan J, Norton M, Bau HH, and Raizen DM: Caenorhabditis-in-Drop array for monitoring C. elegans quiescent behavior. Sleep 36(5): 689-698G, May 2013.

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Last updated: 10/02/2014
The Trustees of the University of Pennsylvania