Nutritional regulation of leptin production

瘦素产生的营养调节

• 批准号: 7890481
• 负责人: Susan K Fried
• 金额: $ 31.97万
• 依托单位: BOSTON MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-06 至 2013-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7890481
• 关键词: 3' Untranslated Regions; 3T3-L1 Cells; 5' Untranslated Regions; A kinase anchoring protein; Abbreviations; Acute; Adenosine Monophosphate; Adipocytes; Adipose tissue; Adrenergic Agents; Adrenergic beta-Agonists; Affect; Anabolism; Binding; Binding Sites; Biological Assay; Biology; Body fat; Catecholamines; Cell Culture Techniques; Cell model; Cells; Chronic; Complex; Cues; Data; Deletion Mutation; Detection; Dexamethasone; Elements; Endocrine; Endoplasmic Reticulum; Family; Genetic Translation; Goals; Growth Factor; Hormones; Human; Hyperinsulinism; Immunity; Immunoprecipitation; In Vitro; Insulin; Insulin Resistance; Interleukin-1; Isoproterenol; Knowledge; Label; Leptin; Link; Luciferases; MAP Kinase Gene; Macronutrients Nutrition; Mediating; Messenger RNA; Metabolic; Metabolism; Mitogen-Activated Protein Kinases; Modeling; Mus; Mutation; Nutrient; Nutritional; Nutritional status; Obesity; Osteogenesis; Pathway interactions; Phosphatidylinositols; Phosphorylation; Phosphotransferases; Physiological; Polyribosomes; Production; Protein Binding; Protein Kinase; Proteins; RNA-Binding Proteins; Rattus; Regulation; Relative (related person); Reporter; Reporter Genes; Reproduction; Research Personnel; Reverse Transcriptase Polymerase Chain Reaction; Ribonucleoproteins; Role; Signal Transduction; Starvation; Stress; System; TNF gene; Testing; Trans-Activators; Transfection; Translations; Tumor Necrosis Factor-alpha; Tumor Necrosis Factors; Untranslated Regions; Up-Regulation; Variant; Work; adipocyte biology; adipokines; adrenergic; basal insulin; cytokine; energy balance; feeding; human FRAP1 protein; in vivo; interest; mRNA Stability; mTOR Signaling Pathway; messenger ribonucleoprotein; nucleocytoplasmic transport; nucleoprotein kinase; overexpression; programs; protein expression; protein kinase R; research study; response; 3' Untranslated Regions; 3T3-L1 Cells; 5' Untranslated Regions; A kinase anchoring protein; Abbreviations; Acute; Adenosine Monophosphate; Adipocytes; Adipose tissue; Adrenergic Agents; Adrenergic beta-Agonists; Affect; Anabolism; Binding; Binding Sites; Biological Assay; Biology; Body fat; Catecholamines; Cell Culture Techniques; Cell model; Cells; Chronic; Complex; Cues; Data; Deletion Mutation; Detection; Dexamethasone; Elements; Endocrine; Endoplasmic Reticulum; Family; Genetic Translation; Goals; Growth Factor; Hormones; Human; Hyperinsulinism; Immunity; Immunoprecipitation; In Vitro; Insulin; Insulin Resistance; Interleukin-1; Isoproterenol; Knowledge; Label; Leptin; Link; Luciferases; MAP Kinase Gene; Macronutrients Nutrition; Mediating; Messenger RNA; Metabolic; Metabolism; Mitogen-Activated Protein Kinases; Modeling; Mus; Mutation; Nutrient; Nutritional; Nutritional status; Obesity; Osteogenesis; Pathway interactions; Phosphatidylinositols; Phosphorylation; Phosphotransferases; Physiological; Polyribosomes; Production; Protein Binding; Protein Kinase; Proteins; RNA-Binding Proteins; Rattus; Regulation; Relative (related person); Reporter; Reporter Genes; Reproduction; Research Personnel; Reverse Transcriptase Polymerase Chain Reaction; Ribonucleoproteins; Role; Signal Transduction; Starvation; Stress; System; TNF gene; Testing; Trans-Activators; Transfection; Translations; Tumor Necrosis Factor-alpha; Tumor Necrosis Factors; Untranslated Regions; Up-Regulation; Variant; Work; adipocyte biology; adipokines; adrenergic; basal insulin; cytokine; energy balance; feeding; human FRAP1 protein; in vivo; interest; mRNA Stability; mTOR Signaling Pathway; messenger ribonucleoprotein; nucleocytoplasmic transport; nucleoprotein kinase; overexpression; programs; protein expression; protein kinase R; research study; response

DESCRIPTION (provided by applicant): The adipocyte hormone leptin regulates energy balance, substrate metabolism, immunity, bone formation and reproduction. Our recent work demonstrates that leptin production is regulated at the translational level, and that elements within its 5' UTR stimulate and its 3' UTRs inhibit translation of a reporter gene. The major goal of this application is to identify the cis elements and trans acting factors that regulate leptin translation in response to variations in nutritional state. The objectives of this application are: 1) To identify RNA binding proteins (RBP) that interact with the leptin 5' and 3'UTRs, and define the cis elements involved; 2) To determine the effect of starvation/feeding in vivo and acute treatment with insulin and beta-adrenergic agonists in vitro on expression of RBPs and their interaction with leptin mRNA; 3) To assess the functional roles of specific RBPs in leptin mRNA translation using knockdown and overexpression studies; and 4) To delineate the signaling mechanisms that cause high basal and insulin-resistant leptin translation in obesity. The leptin 3'UTR includes AU-rich sequences and motifs for binding of RBPs that are known to stimulate (HuR) or inhibit (TIA-1, TIAR) the translation of specific mRNAs. We will therefore determine if leptin mRNA 'in vivo' associates with RBPs 'in vivo' by immunoprecipitating ribonucleoprotein complexes from cytosolic extracts of 3T3-L1 adipocytes and rat adipocytes. Pull-down assays using biotinylated leptin UTR probes will verify the interactions of RBPs of interest and point to the motifs involved. We will test the hypothesis that insulin in vitro or nutritional status in vivo (starvation, feeding) affects the binding of specific RBPs to leptin mRNA, and involves an alteration in their expression and/or nucleocytoplasmic shuttling. Finally, we will test the hypothesis that the chronic hyperinsulinemia associated with obesity increases leptin production at the translational level through the activation of stress / energy sensing pathways (e.g. mTOR, AMPK, and MAPK) and/or by altering the expression or binding of specific RBPs to leptin mRNA. Overall, the proposed studies will enhance understanding of leptin biology and broaden knowledge of how the adipocyte functions as an endocrine cell that orchestrates the production of numerous hormones and cytokines in response to nutritional cues.

描述（由申请人提供）：脂肪细胞激素瘦素调节能量平衡，底物代谢，免疫，骨形成和繁殖。我们最近的工作表明，瘦素的产生受到转化水平的调节，其5'UTR刺激及其3'UTR抑制了记者基因的翻译。该应用的主要目的是确定根据营养状态变化来调节瘦素翻译的顺式元素和反式作用因子。该应用程序的目标是：1）识别与瘦素5'和3'UTRS相互作用的RNA结合蛋白（RBP），并定义涉及的顺式元素； 2）确定体内饥饿/喂养在体内的影响和胰岛素和β-肾上腺素能激动剂在体外对RBPs表达的影响以及它们与瘦素mRNA的相互作用； 3）使用敲低和过表达研究评估特定RBP在瘦素mRNA翻译中的功能作用； 4）描绘肥胖症中引起高基础和胰岛素耐瘦素翻译的信号传导机制。瘦素3'UTR包括富含AU的序列和基序，用于刺激（HUR）或抑制（TIA-1，TIAR）的RBP结合，以特定mRNA的翻译。因此，我们将通过从3T3-L1脂肪细胞和大鼠脂肪细胞的胞质提取物中免疫沉淀的核糖核蛋白络合物来确定瘦素mRNA“体内”与Rbps'在体内'的粘合。使用生物素化瘦素UTR探针进行下拉测定将验证感兴趣的RBP的相互作用，并指向所涉及的基序。我们将检验以下假设：体内体外或营养状况（饥饿，喂养）会影响特定RBP与瘦素mRNA的结合，并涉及其表达和/或核细胞质式班轮的改变。最后，我们将通过激活应力 /能量传感途径（例如MTOR，AMPK和MAPK）和 /或通过改变特定RBPS与瘦素mRNA的表达或结合来测试与肥胖相关的慢性高胰岛素血症在转化水平上增加瘦素的产生。总体而言，拟议的研究将增强对瘦素生物学的理解，并扩大对脂肪细胞作为内分泌细胞如何发挥作用的内分泌细胞的知识，该细胞会依赖于营养线索的响应众多激素和细胞因子的产生。