The overall objective is to define the Ca2+-dependent signaling pathway in hypothalamic neurons that regulates appetite and body weight to provide novel insights to human obesity. AMPK, originally discovered to protect cells against stresses that deplete ATP, is a key enzyme in the pathways by which ghrelin and leptin act on arcuate nucleus (ARM) hypothalamic neurons to control production of NPY and, thus, appetite, energy homeostasis and body weight. Ca2+ is a ubiquitous 2nd messenger that mediates signaling cascades initiated by hormones and growth factors, in which calmodulin (CaM) is the Ca2+ receptor and Ca2+/CaM- dependent protein kinases (CaMK) transduce the Ca2+/CaM signal resulting in many cell responses. A """"""""CaMK cascade"""""""" has been identified composed of Ca2+/CaM, a CaMKK (a or P) and a CaMK (I or IV). Recently the CaMKKs have also been shown to function as AMPKKs and are required to activate AMPK in some human cells. CaMKKp, a brain-specific enzyme, is expressed in the ARM and CaMKKp""""""""'"""""""" mice show decreased hypothalamic AMPK phosphorylation/activity as well as NPY/AgRP mRNAs. Indeed, CaMKKp""""""""'"""""""" mice share many phenotypes with mice null for NPY or an NPY receptor. Infusion of the only selective CaMKK antagonist, STO-609, into the 3rd ventricle of adult wild-type mice results in acute decreases in food intake and body weight as well as hypothalamic content of NPY/AgRP mRNAs. We hypothesize that CaMKKp serves as a primary AMPKK in NPY/AgRP neurons and that acute inhibition of this enzyme leads to decreased production of NPY which causes decreased food intake, altered energy homeostasis and weight loss. To evaluate this hypothesis we will: 1) utilize genetically altered mice to investigate the physiologically relevant role(s) of the CaMKKs, p and a as AMPKKs in mouse hypothalamus and cultured cells to clarify pathways that regulate NPY gene expression and malonyl CoA level;and 2) define the physical interaction between the CaMKKs and AMPK by employing molecular and biochemical technology to understand the nature of the CaMKK/AMPK signaling complex and how this complex can be inhibited. Our results should validate CaMKKp as a target for drug discovery, which could eventually lead to identification of new therapeutics to treat obesity.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM033976-26
Application #
7858187
Study Section
Integrative Physiology of Obesity and Diabetes Study Section (IPOD)
Program Officer
Gerratana, Barbara
Project Start
1984-07-01
Project End
2011-08-31
Budget Start
2010-06-01
Budget End
2011-08-31
Support Year
26
Fiscal Year
2010
Total Cost
$382,239
Indirect Cost
Name
Duke University
Department
Pharmacology
Type
Schools of Medicine
DUNS #
044387793
City
Durham
State
NC
Country
United States
Zip Code
27705
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Marcelo, Kathrina L; Means, Anthony R; York, Brian (2016) The Ca(2+)/Calmodulin/CaMKK2 Axis: Nature's Metabolic CaMshaft. Trends Endocrinol Metab 27:706-718
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Fleet, Tiffany; Zhang, Bin; Lin, Fumin et al. (2015) SRC-2 orchestrates polygenic inputs for fine-tuning glucose homeostasis. Proc Natl Acad Sci U S A 112:E6068-77
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Zhu, Bokai; Gates, Leah A; Stashi, Erin et al. (2015) Coactivator-Dependent Oscillation of Chromatin Accessibility Dictates Circadian Gene Amplitude via REV-ERB Loading. Mol Cell 60:769-783
Marcelo, Kathrina L; Lin, Fumin; Rajapakshe, Kimal et al. (2015) Deciphering hepatocellular responses to metabolic and oncogenic stress. J Biol Methods 2:

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