Hormonal regulation of a Ca2+/AMPK signaling pathway

Ca2 /AMPK 信号通路的激素调节

• 批准号: 8059067
• 负责人: ANTHONY R MEANS
• 金额: $ 15.68万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-15 至 2011-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8059067
• 关键词: Acute; Adult; Binding; Binding Proteins; Biochemical; Blood Glucose; Body Weight; Body Weight decreased; Brain; Ca(2+)-Calmodulin Dependent Protein Kinase; CaM kinase I activator; Calcium/calmodulin-dependent protein kinase; Calmodulin; Catalytic Domain; Cells; Complex; Cultured Cells; Data; Desire for food; Diet; Eating; Enzyme Inhibition; Enzymes; Eukaryota; Exhibits; Family; Fasting; Fatty acid glycerol esters; Feeding behaviors; Food; Gene Expression; Generations; Genes; Glucose; Grant; Growth Factor; Homeostasis; Hormones; Human; Hyperglycemia; Hypothalamic structure; In Vitro; Indirect Calorimetry; Infusion procedures; Knockout Mice; Lead; Leptin; Malonyl Coenzyme A; Mammalian Cell; Mammals; Mediating; Molecular; Mus; NPY gene; Nature; Neurons; Nuclear Translocation; Obesity; Pathway interactions; Phenotype; Phosphorylation; Phosphotransferases; Physiological; Play; Production; Protein Isoforms; Protein Kinase; Protein Phosphatase 2A Regulatory Subunit PR53; Publishing; RNA; Regulation; Relative (related person); Research; Research Personnel; Role; Signal Pathway; Signal Transduction; Stress; Structure of nucleus infundibularis hypothalami; Structure-Activity Relationship; Technology; Transcriptional Activation; Weight Gain; Wild Type Mouse; Yeasts; base; calmodulin-dependent protein kinase II; cell type; drug discovery; energy balance; fatty acid oxidation; feeding; ghrelin; glucose tolerance; hormone regulation; insight; novel; novel therapeutics; programs; receptor; response; scaffold; upstream kinase

DESCRIPTION (provided by applicant): 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.

描述（由申请人提供）：总体目标是确定调节食欲和体重的下丘脑神经元中的Ca 2+依赖性信号通路，以提供对人类肥胖的新见解。AMPK最初被发现用于保护细胞免受消耗ATP的应激，是ghrelin和leptin作用于弓状核（ARM）下丘脑神经元以控制NPY产生并因此控制食欲、能量稳态和体重的途径中的关键酶。Ca ~（2+）是一种普遍存在的第二信使，介导由激素和生长因子引发的信号级联反应，其中钙调素（CaM）是Ca ~（2+）受体，Ca ~（2+）/CaM依赖性蛋白激酶（CaMK）介导Ca ~（2+）/CaM信号，导致许多细胞反应。已经鉴定了由Ca 2 +/CaM、CaMKK（α或β）和CaMK（I或IV）组成的“CaMK级联”。最近，CaMKKs也被证明具有AMPKKs的功能，并且在一些人类细胞中需要激活AMPK。CaMKKp，一种脑特异性酶，在ARM中表达，并且CaMKKp+小鼠显示出降低的下丘脑AMPK磷酸化/活性以及NPY/AgRP mRNA。事实上，CaMKKp+小鼠与无NPY或NPY受体的小鼠共有许多表型。将唯一的选择性CaMKK拮抗剂STO-609输注到成年野生型小鼠的第三脑室中导致食物摄入和体重以及下丘脑NPY/AgRP mRNA含量的急性降低。我们假设CaMKKp作为NPY/AgRP神经元中的主要AMPKK，并且这种酶的急性抑制导致NPY的产生减少，从而导致食物摄入减少，能量稳态改变和体重减轻。为了评估这一假设，我们将：1）利用遗传改变的小鼠来研究CaMKKs、p和a作为AMPKKs在小鼠下丘脑和培养细胞中的生理相关作用，以阐明调节NPY基因表达和丙二酰辅酶A水平的途径;和2）通过使用分子和生物化学技术来理解CaMKK/AMPK的性质，来定义CaMKK和AMPK之间的物理相互作用。AMPK信号复合物以及如何抑制该复合物。我们的研究结果应该验证CaMKKp作为药物发现的目标，这可能最终导致识别治疗肥胖的新疗法。