Adipose Metabolic Profiling for Obesity Drug Targeting

描述（由申请人提供）：本研究项目的长期目标是确定作用于WAT以减少体脂的减肥药的潜在靶点。肥胖正日益成为发达国家的主要健康问题，尤其是美国。流行病学数据指出，体脂（白色脂肪组织，WAT）质量的增加是肥胖的主要原因，脂肪细胞的大小和数量都在增加。目前的饮食疗法的效果大多是可逆的，只有不到10%的减肥者能够保持减肥效果。最近的证据描绘了一幅越来越复杂的脂肪组织代谢调节的画面，脂肪组织分泌自分泌、旁分泌和内分泌因子，调节脂肪细胞和全身能量代谢。鉴于此，减少食物摄入或抑制消化性脂肪吸收的一个有希望的替代方法是通过直接影响脂肪细胞代谢来减少WAT质量。认识到细胞代谢调节的复杂性，本研究采取了一种新颖的，系统导向的方法。为了解决基因和蛋白质表达谱研究留下的知识空白，本提案侧重于获得肥胖和非肥胖脂肪细胞生长的综合代谢信息。该项目通过：1)开发肥胖和正常脂肪细胞生长的组织工程模型系统，2)分析细胞外代谢物浓度和细胞内代谢通量的相关变化，以及3)确定脂肪细胞生长的不同阶段（预脂肪细胞与成熟脂肪细胞）和/或类型（肥胖与正常）的区别标记特征。这些具体目标将通过执行以下任务来实现：a)比较肥胖（Ob17）和非肥胖（3T3-L1）脂肪细胞前体细胞的分化和生长，首先在静态中，然后在生物反应器中培养。将在形态学、生化功能（包括胰岛素敏感性）和生长速度等方面进行比较。微流控生物反应器实验将对共培养的Ob17和3T3-L1细胞进行比较。b)生成代谢谱文库，包括培养基中所有主要初级碳水化合物、氨基酸和脂质代谢物的浓度变化。主要的分析方法将是液相色谱法，c)使用已建立的建模方法生成平行的代谢通量库，d)对代谢物和通量库进行多变量判别分析，以确定每种生长条件下的重要标记。这些程序的预期结果是一个全面的代谢谱和标记库，捕捉肥胖和正常脂肪生长的广泛和独特的特征。这一知识输出标志着全球脂肪能量代谢研究在功能水平上迈出了重要的第一步，并应作为进一步研究肥胖药物靶点脂肪生长主要驱动反应的必要信息平台。

DESCRIPTION (provided by applicant): The long-term objective of this research program is to identify potential targets for obesity drugs that act on WAT to reduce body fat. Obesity is increasingly becoming a leading health problem in developed countries, especially the U.S. Epidemiological data point to increased body fat (white adipose tissue, WAT) mass as a chief contributor to obesity, which occurs both by increases in fat cell size and number. The effects of current dietary therapies are mostly reversible, and less than 10 % of those who lose weight are able to maintain the weight loss. Recent evidence paints an increasingly complex picture of metabolic regulation within the adipose tissue, which secretes autocrine, paracrine, and endocrine factors that regulate adipose cellular and whole body energy metabolism. In light of this picture, a promising alternative to reducing food intake or inhibiting digestive fat absorption is to reduce WAT mass by directly influencing adipose cellular metabolism. Recognizing the complexity of cellular metabolic regulation, this research takes a novel, systems oriented approach. Addressing the knowledge gap left by gene and protein expression profiling studies, this proposal focuses on obtaining comprehensive metabolic information on obese and non-obese adipose cellular growth. The project develops by: 1) developing tissue-engineered model systems for obese and normal adipose cellular growth, 2) profiling associated changes to extracellular metabolite concentrations and intracellular metabolic fluxes, and 3) identifying discriminatory markers characteristic of the various stages (pre- vs. mature adipocyte) and/or types (obese vs. normal) of adipose cellular growth. These specific aims will be achieved by performing the following tasks: a) Compare the differentiation and growth of obese (Ob17) and non-obese (3T3-L1) adipocyte precursor cells, first in static, then bioreactor cultures. Comparisons will be made, among others, on the basis of morphology, biochemical function (including insulin sensitivity), and growth rate. Micro-fluidic bioreactor experiments will perform comparisons of Ob17 and 3T3-L1 cells in co-culture, b) Generate metabolic profile libraries encompassing concentration changes for all major primary carbohydrate, amino acid, and lipid metabolites in culture media. The primary analytical method will be liquid chromatography, c) Generate parallel metabolic flux libraries using established modeling methodologies, d) Perform multivariate discriminant analysis on the metabolite and flux libraries to identify significant markers for each of the growth conditions. The expected outcome of these procedures is a comprehensive library of metabolic profiles and markers that capture both broad and unique features of obese and normal adipose growth. This knowledge output marks a significant first step, at the functional level, in the global study of adipose energy metabolism, and should serve as a necessary information platform for further studies that investigate major driving reactions in adipose growth as obesity drug targets.