Transport and Metabolism of Fatty Acids in Adipocytes

脂肪细胞中脂肪酸的运输和代谢

• 批准号: 6727645
• 负责人: JAMES Athur HAMILTON
• 金额: $ 24.1万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-16 至 2007-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6727645
• 关键词: acidity /alkalinity; adipocytes; caveolas; diabetes mellitus; diffusion; fatty acid binding protein; fatty acid metabolism; fatty acid transport; free fatty acids; glucose; insulin; intracellular transport; laboratory rat; membrane permeability; molecular pathology; mutant; nuclear magnetic resonance spectroscopy; obesity; radiotracer; tissue /cell culture

DESCRIPTION (Scanned from the Applicant's Description): Obesity is the most pervasive health problem in the United States that has no cure or generally effective therapy. While easily recognized at the whole body level, obesity is poorly understood at the cellular level. This project will use new biophysical strategies and molecular biology to study aspects of the transport and metabolism of free fatty acids (FFA) in isolated adipocytes. These in vitro studies allow control of the environment of the cell and evaluation of individual factors that may influence fat storage. We hypothesize, on the basis of previous work and new supportive data, that free diffusion through the plasma membrane is a major if not exclusive pathway for entry and exit of FFA in cells. Uptake of FFA is not regulated by transport proteins but depends on extra-and intracellular concentrations and binding affinities of FFA binding moieties (e.g. albumin, membranes, and intracellular FFA -binding proteins) and on metabolism of FFA. Our model of FFA diffusion through a membrane ("flip-flop") postulates intracellular pH changes that can be detected by a fluorescent pH probe. This approach will be used to test our hypothesis that FFA enter and leave adipocytes efficiently and rapidly by diffusion, and that increased extracellular FFA will lead to increased intracellular FFA. We have also recently developed a 13C NMR approach to study the incorporation of exogenous 13C-labeled FFA into acylated lipid end products. To complement these NMR studies of FFA storage in lipids, we will use a new 13C NMR approach as well as 14C radioisotope methods to measure directly the extent of FFA oxidation into 13C02 or 14C02. Our aims begin with the question of how certain structural features of the adipocyte, the plasma membrane composition, the presence of caveolae, and the expression of different levels of the intracellular FFA-binding protein, aP2, affect the transport and metabolism of FFA. We then examine how extrinsic conditions such as the presence of insulin and/or glucose, the external supply of FFA, and the action of hormones and inhibitors affect FFA transport and metabolic fate. Finally, we use naturally occurring genetic variants as animal models of obesity and diabetes as sources of cells for parallel studies to determine the effects of these pathologies on FFA transport and metabolism. We can then address a key question for formulation of new therapies for obesity: does FFA transport affect the partitioning of FFA between storage and utilization as fuel?

描述（从申请人的描述中扫描）：肥胖是最常见的 美国普遍存在的健康问题，无法治愈或普遍存在 有效的治疗。虽然肥胖在整个身体水平上很容易识别，但 在细胞水平上知之甚少。该项目将采用新的生物物理学 策略和分子生物学来研究运输和 分离脂肪细胞中游离脂肪酸（FFA）的代谢。这些在体外 研究允许控制细胞环境并评估 可能影响脂肪储存的个体因素。我们假设，基于 以前的工作和新的支持数据，通过 质膜是 FFA 进出的主要途径（即使不是唯一途径） 在细胞中。 FFA 的摄取不受转运蛋白调节，而是取决于 FFA 结合的细胞外和细胞内浓度以及结合亲和力 部分（例如白蛋白、膜和细胞内 FFA 结合蛋白）和 FFA 代谢的影响我们的 FFA 膜扩散模型 （“触发器”）假设细胞内 pH 值的变化可以通过 荧光 pH 探针。这种方法将用于检验我们的假设 FFA 通过扩散有效、快速地进入和离开脂肪细胞，并且 细胞外 FFA 增加将导致细胞内 FFA 增加。我们有 最近还开发了一种 13C NMR 方法来研究 外源 13C 标记的 FFA 转化为酰化脂质终产物。为了补充这些 脂质中 FFA 储存的 NMR 研究，我们将使用新的 13C NMR 方法作为 以及直接测量 FFA 范围的 14C 放射性同位素方法 氧化成13CO2或14CO2。我们的目标始于这样一个问题： 脂肪细胞的结构特征、质膜组成、 小凹的存在以及不同水平的表达 细胞内 FFA 结合蛋白 aP2 影响 FFA 的转运和代谢 FFA。然后我们检查外在条件（例如胰岛素的存在）如何 和/或葡萄糖、FFA 的外部供应以及激素和 抑制剂影响 FFA 转运和代谢命运。最后我们自然地使用 发生的遗传变异作为肥胖和糖尿病动物模型的来源 细胞进行平行研究以确定这些病理学对 FFA 运输和代谢。然后我们可以解决一个关键问题 肥胖新疗法的制定：FFA 转运是否会影响 FFA 的存储和用作燃料之间的划分？