Stable isotope-based fate mapping to quantify adipogenesis in obesity

基于稳定同位素的命运图谱可量化肥胖中的脂肪生成

• 批准号: 8242402
• 负责人: Matthew Steinhauser
• 金额: $ 16.02万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8242402
• 关键词: 2,4-thiazolidinedione; Address; Adipocytes; Adipose tissue; Adult; Area; Beryllium; Biological; Blood Vessels; DNA biosynthesis; Data; Date of birth; Defect; Diabetes Mellitus; Diet; Disease; Epidemic; Fatty Acids; Fatty acid glycerol esters; Generations; Genetic; Genetically Engineered Mouse; Homeostasis; Human; In Vitro; Insulin; Insulin Resistance; Intervention; Isotopes; Life; Link; Maintenance; Maps; Mass Spectrum Analysis; Metabolic; Methodology; Methods; Microscope; Microscopy; Morbidity - disease rate; Morphologic artifacts; Mus; Neutrons; Non-Insulin-Dependent Diabetes Mellitus; Obesity; PPAR gamma; Pharmacotherapy; Physiologic pulse; Process; Radioactive; Radioisotopes; Randomized; Regenerative Medicine; Relative (related person); Resolution; Rodent; Role; Safety; Stable Isotope Labeling; Testing; Therapeutic; Thiazolidinediones; Thymidine; Tissues; Tracer; Visceral; Weight; Work; base; feeding; human stem cells; in vivo; insight; insulin sensitivity; isotope incorporation; lipid biosynthesis; mortality; novel; novel strategies; research study; response; stable isotope; stem cell biology; stem cell population; subcutaneous; theories; transcription factor

DESCRIPTION (provided by applicant): Recent evidence from human studies suggests that adipocytes turnover throughout adult life. While it has long been thought that adult adipocytes are generated from a stem cell population, recent lineage mapping experiments in mice provide strong evidence for an adipocyte precursor residing within adipose tissue. Many questions regarding the role of adipocyte turnover during normal homeostasis and in obesity remain incompletely elucidated, in large part because there have not been definitive methods to quantitate adipogenesis in vivo. The central hypothesis of this project is that caloric excess results in dynamic changes in precursor-dependent white adipose turnover. Deconstructing the role of adipogenesis in obesity and diabetes will not only yield important mechanistic insight into these disease processes, but may provide the rationale to directly target adipogenesis with pharmacotherapies. To address the central hypothesis, novel approaches to quantitate adipogenesis in vivo using stable isotope labeling and two mass spectrometry based platforms will be utilized. Rare stable isotopes differ in mass from more common isotopic forms of elements, but they are not radioactive, and thus are entirely safe and biologically inert. Preliminary data suggests that stable isotope-enriched thymidine is an effective tracer to detect DNA synthesis and cellular division. Using pulse-chase strategies and mass spectrometry, including multi-isotope mass spectrometry (MIMS) an exciting new microscopy methodology that can detect areas of stable isotope incorporation within tissues with sub-cellular resolution, adipogenesis can be quantified after biologically relevant interventions, in vivo. Aim 1: To test the hypothesis that high fat feeding will result in a dynamic increase in white adipose adipogenesis. Adult mice will be randomized to a normal diet or an adipogenic (high-fat) diet, and two stable isotope based approaches will be used to determine whether adipose expansion as occurs in obesity is associated with increased generation of new adipocytes. Aim 2: To test the hypothesis that prolonged high fat feeding with resultant obesity-related insulin resistance results in a relative deficiency in subcutaneous adipogenesis in favor of increased visceral adipogenesis. The rates of adipogenesis will be compared between obese and lean mice in response to a high fat diet, with the aim to answer the question of whether obesity results in depot specific defects in adipogenesis, which may contribute to coexistent insulin resistance. Aim 3: To test the hypothesis that PPAR-gamma activation will stimulate white adipose adipogenesis, in vivo. Stable isotope methods will be used to quantitate adipogenesis after pharmacologic stimulation of PPAR-gamma with a thiazolidinedione in obese and lean mice. PUBLIC HEALTH RELEVANCE: Obesity and Type 2 Diabetes Mellitus represent major causes of morbidity and mortality in the developed world. Defining the capacity to generate new fat cells in states of Obesity and Diabetes may yield a critical mechanistic link between these related diseases. This project will study the role of new fat cell formation in obesity and diabetes, an understanding of which may provide the therapeutic rationale to pharmacologically control fat cell formation.

描述（由申请人提供）：人类研究的最新证据表明，脂肪细胞在整个成人生活中流动。尽管长期以来一直认为成年脂肪细胞是由干细胞种群产生的，但在小鼠中，最近的谱图映射实验为属于脂肪组织内的脂肪细胞前体提供了有力的证据。关于正常稳态和肥胖症中脂肪细胞更新的作用的许多问题仍然没有完全阐明，这在很大程度上是因为没有确定的方法可以在体内定量脂肪形成。该项目的核心假设是热量过剩会导致前体依赖性白脂肪更新的动态变化。解构脂肪形成在肥胖和糖尿病中的作用不仅会对这些疾病过程产生重要的机理洞察力，而且可以提供直接用药物疗法靶向脂肪形成的理由。为了解决中心假设，将利用使用稳定的同位素标记和两个基于质谱的平台在体内定量脂肪形成的新方法。稀有稳定的同位素在质量上与更常见的同位素元素形式不同，但它们不是放射性的，因此完全安全且在生物学上是惰性的。初步数据表明，稳定的同位素增强的胸苷是检测DNA合成和细胞分裂的有效示踪剂。使用脉冲追踪策略和质谱法，包括多个同位素质谱法（MIMS）一种令人兴奋的新显微镜方法，可以检测具有亚细胞分辨率的组织中稳定同位素掺入的区域，可以在生物学相关的干预后，在体内量化脂肪形成。目的1：测试假说，即高脂肪进食将导致白色脂肪脂肪形成的动态增加。成年小鼠将被随机分配为正常饮食或脂肪成生（高脂饮食），并将使用两种稳定的基于同位素的方法来确定肥胖症中发生的脂肪膨胀是否与新的脂肪细胞的产生增加有关。目的2：检验以下假设：延长高脂肪喂养，导致与肥胖相关的胰岛素耐药性导致皮下脂肪生成相对缺乏，而支持内脏脂肪生成增加。肥胖小鼠和瘦小小鼠之间的脂肪形成率将以高脂肪饮食的形式进行比较，目的是回答肥胖症是否导致脂肪生成中库的特定缺陷的问题，这可能有助于共存的胰岛素抵抗。目的3：测试PPAR-GAMMA激活将刺激白色脂肪脂肪形成的假设，体内。稳定的同位素方法将用于在肥胖和瘦小小鼠中用硫酚固定的药物刺激PPAR-GAMMA后的脂肪形成。 公共卫生相关性：肥胖和2型糖尿病是发达国家发病和死亡率的主要原因。定义在肥胖状态和糖尿病状态下产生新脂肪细胞的能力可能会在这些相关疾病之间产生关键的机理联系。该项目将研究新的脂肪细胞形成在肥胖症和糖尿病中的作用，该项目的理解可能为在药理学控制脂肪细胞形成的治疗基本原理提供。