Interaction of Estrogen and AMPK in the Hypothalamus

下丘脑中雌激素和 AMPK 的相互作用

• 批准号: 8314613
• 负责人: Jessica Healy
• 金额: $ 2.24万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-03-19 至 2012-08-23
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8314613
• 关键词: 5' -AMP-activated protein kinase; AMP-activated protein kinase kinase; ART protein; Acetyl-CoA Carboxylase; Adult; Affect; Agonist; Atherosclerosis; Behavioral Risk Factor Surveillance System; Binding; Breast Cancer Cell; Calcium; Calcium/calmodulin-dependent protein kinase; Cannulas; Cell Culture Techniques; Cells; Centers for Disease Control and Prevention (U.S.); Complex; Data; Diabetes Mellitus; Diestrus; Dose; Eating; Environment; Enzymes; Estradiol; Estrogen Receptors; Estrogens; Fatty Acids; Female; Gene Expression; Gene Proteins; Genetic Transcription; Genomics; Goals; Health; Heart Diseases; Hormones; Human; Hyperphagia; Hypothalamic structure; Implant; In Vitro; Individual; Injection of therapeutic agent; Insulin; Intervention; Lead; Leptin; Light; Liver; Location; Malignant Neoplasms; Membrane; Menopause; Messenger RNA; Modeling; Neurons; Neuropeptides; Obesity; Ovariectomy; Pathology; Pathway interactions; Peptides; Phenotype; Phosphorylation; Phosphotransferases; Population; Pro-Opiomelanocortin; Proestrus; Proteins; Rattus; Reaction Time; Relative (related person); Reverse Transcriptase Polymerase Chain Reaction; Rodent; STK11 gene; Signal Pathway; Signal Transduction; Societies; Stroke; Structure of nucleus infundibularis hypothalami; Testing; Transfection; Western Blotting; Woman; cost; density; design; energy balance; estradiol-bovine serum albumin; extracellular; fatty acid oxidation; ghrelin; heart disease risk; immunoreactivity; in vivo; knock-down; neuropeptide Y; non-genomic; prevent; promoter; protein expression; reproductive; reproductive hormone; research study; response; small hairpin RNA

DESCRIPTION (provided by applicant): The goal of this project is to determine the mechanism by which estradiol affects the food intake pathway in the mammalian hypothalamus. Obesity is of growing concern in Western society, mainly due to its associated pathologies, including diabetes, atherosclerosis, and heart disease. In women, decreases in estradiol occur during menopause and may lead to hyperphagia and obesity. Estradiol is anorexigenic in rodents and humans. Food intake is regulated by a variety of exigenic neuropeptides (neuropeptide Y, NPY; agouti-related protein, AgRP) and anorexigenic neuropeptides (pro- opiomelanocortin, POMC) that act in the hypothalamus. All of these neuropeptides appear to be estrogen-regulated and neurons expressing these peptides also express estrogen receptors. NPY, AgRP, and POMC are also regulated by the cellular energy sensing enzyme AMP-activated protein kinase (AMPK), which is phosphorylated (pAMPK) by the enzyme liver kinase B1 (LKB1) and activated when a decrease in the AMP:ATP ratio signals low endogenous energy. Activation of AMPK results in an increase in food intake. Ovariectomized female rats (lacking estradiol) become obese and have increased expression of hypothalamic pAMPK; however, the mechanism by which estradiol affects hypothalamic AMPK is unknown. The hypothesis of this proposal is that estradiol, acting through estrogen receptor ¿ (ER¿), decreases expression of LKB1, thereby decreasing phosphorylation and activation of AMPK and reducing food intake. To test this hypothesis, changes in gene and protein expression of LKB1 and AMPK will be examined both in vitro and in vivo in the presence and absence of estradiol, utilizing cell culture, transfection, Western blotting, quantitative RT-PCR, ovariectomy and intracerebroventricular injection. Preliminary data suggest that estradiol treatment in N-38 hypothalamic cells decreases the proportion of active to inactive AMPK, and decreases relative abundance of NPY, in effect signaling an environment of high available energy. These data point to a potential mechanism for estradiol to impact energy balance by preventing the phosphorylation and activation of AMPK. Therefore, the purpose of this project is to test the hypothesis that estradiol impacts the hypothalamic food intake pathway through its actions on AMPK, thereby shedding light on the cellular pathways underlying obesity and providing information for possible pharmacological interventions on the pathologies associated with the condition of obesity. PUBLIC HEALTH RELEVANCE: As of 2010, approximately one third of the U.S. population was considered obese (BMIe30), and no state had less than 20% obesity in its adult population (CDC BRFSS 2010). Obese individuals are at increased risk for heart disease, diabetes, certain cancers, stroke and reproductive problems, and health problems related to obesity cost about $147 billion per year (Finkelstein et al. 2009). The proposed project will investigate the cellular mechanisms underlying the interaction between food intake and reproductive hormones, and the results may be useful in mitigating the pathological effects of certain types of obesity.

描述（由申请人提供）：该项目的目的是确定雌二醇影响哺乳动物下丘脑食物摄入途径的机制。肥胖在西方社会越来越受到关注，主要是由于其相关的病理，包括糖尿病、动脉粥样硬化和心脏病。在女性中，雌二醇的减少发生在更年期，并可能导致嗜食和肥胖。雌二醇在啮齿动物和人类中是厌氧性的。食物摄入受多种作用于下丘脑的外生神经肽（神经肽Y， NPY； agouti相关蛋白，AgRP）和厌氧神经肽（前鸦片黑素皮质素，POMC）的调节。所有这些神经肽似乎都受雌激素调节，表达这些肽的神经元也表达雌激素受体。NPY、AgRP和POMC也受细胞能量感应酶AMP活化蛋白激酶（AMPK）的调控，AMPK被肝激酶B1酶（LKB1）磷酸化（pAMPK），当AMP:ATP比值降低信号内源能量低时被激活。AMPK的激活会导致食物摄入量的增加。去卵巢的雌性大鼠（缺乏雌二醇）变得肥胖，下丘脑pAMPK的表达增加；然而，雌二醇影响下丘脑AMPK的机制尚不清楚。本研究的假设是雌二醇通过雌激素受体（ER）降低LKB1的表达，从而降低AMPK的磷酸化和激活，减少食物摄入量。为了验证这一假设，我们将利用细胞培养、转染、Western blotting、定量RT-PCR和卵巢切除术，在体外和体内检测雌二醇存在和不存在情况下LKB1和AMPK基因和蛋白质表达的变化