SuJean Choi

Assistant Professor

B.S. 1989, University of Michigan

Ph.D. 1995, University of Rochester

 

Schroeder Complex 429F

(414) 288-4533

E-Mail

The general research theme in the Choi lab examines the central mechanisms of energy regulation through serotonin and/or neuropeptide interactions and feeding behavior.

Current projects include the central nervous system mechanisms by which drugs and neurotransmitters increase or decrease hunger and food intake and subsequently body weight following various procedures such as drug therapy. Specifically, we investigate the influence of serotonin and its associated neurons in the hypothalamic paraventricular nuclei on neuronal corticotropin releasing factor mRNA expression and feeding behavior in rats. Paraventricular corticotropin releasing factor neurons are important mediators in the control of feeding behavior. Similarly, drugs that stimulate synaptic serotonin transmission in the brain are also well known to inhibit food intake. Anatomically, it is also known that serotonin terminal projections are found on paraventricular corticotropin releasing factor neurons; this suggests that serotonin agents may suppress appetite through heretofore uncharacterized actions on paraventricular corticotropin releasing factor neurons. Remarkably, there have been no definitive studies to date demonstrating that serotonin-associated drugs may indeed suppress feeding by stimulating corticotropin releasing factor mRNA and protein production. Thus, we hypothesize that there exists a functional link between serotonin and neuropeptides such as corticotropin releasing factor and their respective neurons residing in the hypothalamus. As a tool to address our hypothesis, I have been developing a novel method to discretely and temporarily suppress gene expression and protein production through the use of long double-stranded RNA induced RNAi in vivo. This method has great potential as a physiological and neuroanatomical tool that can help to define the roles of small groups of neurons in the brain.

Overall, these studies investigate functional activity and responsivity of brain signals participating in the neuroanatomical circuitry of feeding and metabolism. The results of these studies will provide a broader picture of how organisms regulate and maintain their energy balance and respond to their external environment, as well as provide a basic science backdrop to better understand the clinical pathologies of obesity, eating disorders, metabolic disorders, and depression and perhaps contribute to their future therapeutic strategies.

Methods used in my laboratory include basic molecular biology, histology, immunocytochemistry, small animal surgery, behavioral observation, endocrinology, neurochemistry, and image analysis.

Selected References

Fernstrom, J.D. & Choi, S (2007) The development of tolerance to drugs that suppress food intake. Pharmacology and Therapeutics. 117(1): 105-122.

Choi, S., Blake, V., Cole, S., Fernstrom, J.D. (2006) Effects of chronic fenfluramine administration on hypothalamic neuropeptide mRNA expression. Brain Research 1087:83-86

Bhargava, A., Dallman, M.F., Pearce, D., Choi, S. (2004) Long double-stranded RNA-mediated RNA interference as a tool to achieve site specific silencing of hypothalamic neuorpeptides. Brain Research Protocols. 13:115-25.