title: Regulation of energy stores and feeding by neuronal and peripheral CREB activity in Drosophila.
abstract: The cAMP-responsive transcription factor CREB functions in adipose tissue and liver to regulate glycogen and lipid metabolism in mammals. While Drosophila has a homolog of mammalian CREB, dCREB2, its role in energy metabolism is not fully understood. Using tissue-specific expression of a dominant-negative form of CREB (DN-CREB), we have examined the effect of blocking CREB activity in neurons and in the fat body, the primary energy storage depot with functions of adipose tissue and the liver in flies, on energy balance, stress resistance and feeding behavior. We found that disruption of CREB function in neurons reduced glycogen and lipid stores and increased sensitivity to starvation. Expression of DN-CREB in the fat body also reduced glycogen levels, while it did not affect starvation sensitivity, presumably due to increased lipid levels in these flies. Interestingly, blocking CREB activity in the fat body increased food intake. These flies did not show a significant change in overall body size, suggesting that disruption of CREB activity in the fat body caused an obese-like phenotype. Using a transgenic CRE-luciferase reporter, we further demonstrated that disruption of the adipokinetic hormone receptor, which is functionally related to mammalian glucagon and beta-adrenergic signaling, in the fat body reduced CRE-mediated transcription in flies. This study demonstrates that CREB activity in either neuronal or peripheral tissues regulates energy balance in Drosophila, and that the key signaling pathway regulating CREB activity in peripheral tissue is evolutionarily conserved.
authors.affiliation: Laboratory of Neurodegenerative and Metabolic Diseases, Farber Institute for Neurosciences, Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America. kanae.iijima-ando@jefferson.edu
authors.forename: Koichi
authors.initials: K
authors.lastname: Iijima
authors.forename: LiJuan
authors.initials: L
authors.lastname: Zhao
authors.forename: Christopher
authors.initials: C
authors.lastname: Shenton
authors.forename: Kanae
authors.initials: K
authors.lastname: Iijima-Ando
mesh_terms: D000375:Aging / Q000378:metabolism; D000818:Animals; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism*; D004734:Energy Metabolism; D005216:Fat Body / Q000378:metabolism; D005247:Feeding Behavior; D055785:Gene Knockdown Techniques; D006003:Glycogen / Q000378:metabolism; D050356:Lipid Metabolism; D009474:Neurons / Q000378:metabolism*; D018384:Oxidative Stress; D018027:Receptors, Glucagon / Q000378:metabolism; D020218:Response Elements / Q000235:genetics; D013217:Starvation; D013312:Stress, Physiological; D015534:Trans-Activators / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: C533337:AKHR protein, Drosophila; C102181:CrebB protein, Drosophila; D017362:Cyclic AMP Response Element-Binding Protein; D029721:Drosophila Proteins; D018027:Receptors, Glucagon; D015534:Trans-Activators; D006003:Glycogen