STEROID REGULATION OF B-ADRENORECEPTOR GENES IN OBESITY

肥胖中 B 肾上腺素受体基因的类固醇调节

• 批准号: 2146042
• 负责人: SHEILA COLLINS
• 金额: $ 9.15万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-07-01 至 1999-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2146042
• 关键词: G protein; RNase protection assay; adenylate cyclase; adipocytes; adipose tissue; adrenalectomy; beta adrenergic receptor; biological signal transduction; cell differentiation; corticosteroid inhibitor; gel mobility shift assay; gene expression; genetic models; genetic promoter element; genetic transcription; glucocorticoids; hormone regulation /control mechanism; laboratory mouse; lipolysis; northern blottings; nuclear runoff assay; obesity; receptor binding; receptor expression; tissue /cell culture; G protein; RNase protection assay; adenylate cyclase; adipocytes; adipose tissue; adrenalectomy; beta adrenergic receptor; biological signal transduction; cell differentiation; corticosteroid inhibitor; gel mobility shift assay; gene expression; genetic models; genetic promoter element; genetic transcription; glucocorticoids; hormone regulation /control mechanism; laboratory mouse; lipolysis; northern blottings; nuclear runoff assay; obesity; receptor binding; receptor expression; tissue /cell culture

The congenital obesity, beta-adrenergic receptor (betaAR) stimulation of lipolysis and thermogenesis are impaired. Both white and brown adipocytes express beta1-, beta2-, and beta3AR (the latter is expressed exclusively in fat). Our preliminary data demonstrate that beta1AR and beta3AR are impaired in white and brown adipocytes from genetically obese (ob/ob) mice compared to lean controls. This defect may contribute to the obese state. In addition, the stimulatory G-protein (Gs) alpha subunit, to which betaARs are coupled, is depressed in obese animals. Since elevated corticosteroid (CORT) levels are an essential feature promoting obesity, and betaAR subtype expression can be modulated by CORTs, regulation of betaAR subtype gene transcription by this steroid may be an important component of obesity. There are 4 major aims of this research plan. (1) Changes in betaAR and Gsalpha will be monitored during the development of obesity. The mRNA levels of the beta1AR, beta2AR beta3AR and Gsalpha genes, radioligand binding and beta-agonist- stimulated adenylyl cyclase activity will be measured in white and brown adipose tissue from lean and obese mice from 1 week to 14 weeks of age. Adipocyte-specific markers will also be monitored. (2) The effect of CORT on expression of betaAR subtypes and Gsalpha genes in brown and white fat, and their effects on obesity will be assessed in 2 ways: (i) Adrenalectomized obese mice will be studied over the same developmental period outlined in Aim 1. (ii) Lean and obese mice will be treated chronically with the CORT antagonist RU38486 over the same period as in Aim 1. Results from Aims 1 and 2 will provide a basis for examining more specific molecular and cellular mechanisms regulating betaAR and Gsalpha gene expression. (3) Established murine preadipocyte cell lines of white and brown fat origin will be used to examine the molecular mechanisms regulating transcription of betaAR subtypes and Gsalpha genes during adipocyte differentiation and CORT exposure. Nuclear run-on transcription, mRNA half-life, and cycloheximide sensitivity studies will determine specific molecular mechanisms responsible for observed changes in individual betaAR and Gsalpha transcripts. These data will be related to results obtained from lean and obese mice in vivo in Aims 1 and 2. (4) Transfection studies with betaAR promoter-reporter constructs in pre- and differentiated adipocytes are designed to identify regulatory elements involved in adipocyte differentiation and CORT regulation of betaAR transcription. Together, these integrated studies should more directly define the physiological, cellular and molecular mechanisms regulating betaAR signal transduction in adipocytes during the development of obesity.

先天性肥胖，β-肾上腺素能受体（betaar）刺激 脂解和热发生受损。 白色和棕色 脂肪细胞Express beta1-，beta2-和beta3ar（后者表示 仅在脂肪中）。 我们的初步数据表明beta1ar和 beta3ar受遗传性肥胖的白色和棕色脂肪细胞受损 （OB/OB）小鼠与瘦对手相比。 这种缺陷可能有助于 肥胖国家。 另外，刺激G蛋白（GS）α 肥胖动物抑制了Betaars耦合的亚基。 由于升高的皮质类固醇（Cort）水平是重要的特征 促进肥胖和betaar亚型表达可以通过 Corts，该类固醇的betaar亚型基因转录的调节 可能是肥胖的重要组成部分。 有4个主要目标 研究计划。 （1）将监视Betaar和Gsalpha的变化 在肥胖的发展过程中。 beta1ar的mRNA水平， beta2ar beta3ar和gsalpha基因，放射性基因结合和β-激动剂 - 刺激的腺苷酸环化酶活性将以白色和棕色测量 从1周至14周龄的瘦小小鼠和肥胖小鼠的脂肪组织。 还将监视脂肪细胞特异性标记。 （2） 棕色和gsalpha基因在棕色和 白脂及其对肥胖的影响将通过两种方式进行评估：（i） 肾上腺切除肥胖小鼠将在同一发育性上进行研究 AIM 1中概述的时期。 与Cort拮抗剂RU38486在同一时期长期与Cort拮抗剂Ru38486 目标1。目标1和2的结果将为检查更多 调节betaar和gsalpha的特定分子和细胞机制 基因表达。 （3）已建立的白色鼠前红细胞细胞系 和棕色脂肪起源将用于检查分子机制 调节βAR亚型和GSALPHA基因的转录 脂肪细胞分化和cort暴露。 核跑步 转录，mRNA半衰期和环己酰亚胺敏感性研究将 确定负责观察到的变化的特定分子机制 在单独的betaar和gsalpha转录本中。 这些数据将相关 在AIM 1和2中从体内瘦小小鼠和肥胖小鼠获得的结果。 （4）在贝塔尔启动子重生构建体中的转染研究 和分化的脂肪细胞旨在识别调节 参与脂肪细胞分化和Cort调节的元素 betaar转录。 这些综合研究在一起应该更多 直接定义生理，细胞和分子机制 调节脂肪细胞中betaar信号转导期间 肥胖的发展。