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Energy Homeostasis: GABAergic and Non-GABAergic POMC neurons

能量稳态：GABA 能和非 GABA 能 POMC 神经元

基本信息

批准号：
9493040
负责人：
YOUNG-HWAN JO
金额：
$ 33.4万
依托单位：
ALBERT EINSTEIN COLLEGE OF MEDICINE, INC
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-07-13 至 2018-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9493040
关键词：
Ablation Appetite Stimulants Award Blood Glucose Cells Chimeric Proteins DNA cassette Dependovirus Diabetes Mellitus Energy Intake Energy Metabolism Enhancers Enterobacteria phage P1 Cre recombinase Equilibrium Fasting Foundations Genes Genetically Engineered Mouse Gluconeogenesis Glucose Glucose Intolerance Hepatic Heterogeneity Homeostasis Hypothalamic structure Induced Mutation Knowledge Liver Liver Glycogen Maps Mediating Metabolic syndrome Modeling Molecular Motor Activity Neuroanatomy Neurobiology Neurons Nutrient Obesity Opioid Organ Outcome Physiological Play Pro-Opiomelanocortin Process Regulation Role Signal Transduction Site Spinal Cord Column Structure of nucleus infundibularis hypothalami System Viral Wheat Germ Agglutinins blood glucose regulation dorsal motor nucleus glucose metabolism glucose production glycogenolysis in vivo innovation interest liver metabolism neural circuit neurochemistry novel therapeutic intervention optogenetics postnatal public health relevance relating to nervous system response temporal measurement

项目摘要

The hypothalamic neurons are major components of the neural circuits that control energy homeostasis. Proopiomelanocortin (POMC) neurons in the arcuate nucleus (ARC) play a major role in regulating energy intake, energy expenditure, and glucose metabolism. In our studies under the previous award from July 13, 2012 to present, we have clearly demonstrated molecular and neurochemical heterogeneity of POMC neurons in the ARC and that distinct subpopulations of POMC neurons directly and indirectly interact in a manner that is critical to the net outcome of the melanocortin signaling. In addition to this neurochemical heterogeneity, neuroanatomical studies have revealed that distinct sets of POMC neurons project to different target sites. This neurochemical and neuroanatomical heterogeneity of ARC POMC neurons, combined with their broad functional repertoire, strongly support the idea that there is functional heterogeneity of ARC POMC neurons. As our specific aims under the previous award have been completed, we now propose that neurochemically distinct subpopulations of POMC neurons have distinct target organs and functions. The liver is the main glucose supplier in overnight fasting and short term fasting. Hepatic glucose production results either from de novo synthesis via gluconeogenesis or from degradation of hepatic glycogen via glycogenolysis. This process appears to be regulated by the central melanocortin system. For instance, ARC POMC neurons project to liver and postnatal ablation of POMC neurons elevates blood glucose levels and induces glucose intolerance. However, there still exist foundational gaps in our knowledge of the neurobiology and neuroanatomy of the central melanocortin system that regulates liver metabolism. Our preliminary studies show that a subpopulation of ARC POMC neurons innervate liver through two autonomic centers, including the intermediolateral cell column of the spinal cord and the dorsal motor nucleus of the vagus. These neuroanatomical studies raise questions as to what types of POMC neurons project to liver and which autonomic circuits are used by POMC neurons to regulate hepatic glucose production. In fact, recent studies with genetically engineered mice that have induced mutations exclusively in POMC neurons have demonstrated that energy intake, energy expenditure, glucose metabolism, and locomotor activity are regulated by distinct sets of POMC neurons. As there exist liver-projecting ARC POMC neurons, we hypothesize that these liver-projecting ARC POMC neurons play a key role in the regulation of hepatic glucose production. In Aim 1, we will thoroughly examine the neurochemical and neuroanatomical identity of ARC POMC neurons projecting to liver. And then we will explore the physiological impact of liver-projecting POMC neuron stimulation on hepatic glucose production in Aim 2. In summary, we will incorporate optogenetics with viral-mediated delivery of the Cre recombinase gene to achieve organ-specific optogenetic control that is highly innovative. As we can manipulate exclusively liver-projecting POMC neuron activity in vivo with high temporal resolution, this will significantly expand our capability to probe the causal relationship between the melanocortin signaling and hepatic glucose homeostasis.

下丘脑神经元是控制神经回路的主要组成部分