The Role of Substrate Metabolism and Macrophage Activation in Obesity

描述(申请人提供)：世界卫生组织估计有5亿成年人和多达4300万5岁以下儿童患有肥胖症，强调肥胖及其相关疾病，包括胰岛素抵抗和糖尿病，仍然是一个重大的全球公共卫生问题。过去十年进行的研究越来越多地将肥胖和炎症联系在一起；先天免疫系统中典型激活的促炎M1巨噬细胞在体重增加开始时渗透到脂肪组织中，导致脂肪的炎症状态，最终导致全身胰岛素抵抗，而交替激活的抗炎M2巨噬细胞则保护代谢组织中的胰岛素敏感性。控制巨噬细胞亚型的机制尚不清楚，可能是组织微环境中巨噬细胞可获得的能量底物的类型，或这些细胞利用特定底物作为燃料的能力之一。 巨噬细胞表型的调控机制。这项提案的目的1将通过使用巨噬细胞特异性葡萄糖转运蛋白1基因敲除小鼠(Glut1 M？/-)和饮食诱导肥胖的高脂喂养模型来探索限制燃料底物供应如何影响巨噬细胞亚型(即促炎和抗炎)。代谢表型，包括体重和组成，食物摄入量和活动量，全身性胰岛素敏感性和葡萄糖耐量，以及能量消耗将在瘦肉型和肥胖型Glut1 M？/-和野生型对照仔猪身上进行。将结合组织学、基因和蛋白质表达分析，确定附睾白脂肪组织(EWAT)中巨噬细胞的渗透程度，以及巨噬细胞亚型和eWAT胰岛素信号通路的修饰。最后，将通过基因组微阵列分析和代谢组谱分析来表征巨噬细胞表型对eWAT微环境的总体影响。肥胖被认为是一种免疫抑制状态，疾病控制和预防中心现在承认肥胖是流感发病率和死亡率增加的独立风险因素。本建议的目的2将探讨肥胖、巨噬细胞表型和流感感染之间的关系以及它们对流感感染严重程度的联合影响。Glut1M？-/-/饮食诱导的肥胖模型将与目标1中一样使用，并增加了流感感染。总体生存、肺病理、病毒清除和免疫细胞群特征将完成。这个项目将提供一个机会，与肥胖和传染病公共卫生领域的一群备受尊敬的研究人员密切合作，并得到他们的指导。完成这一研究项目将最终掌握一些技能，如进行受控动物喂养研究、代谢表型、免疫系统特征、大型基因组和代谢组学数据集的生物信息学分析、手稿写作、数据展示、宏大技巧和研究项目管理。

DESCRIPTION (provided by applicant): The World Health Organization estimates 500 million adults and as many as 43 million children under the age of 5 are obese underscoring the fact that obesity and its related diseases, including insulin resistance and diabetes, remains a significant global public health problem. Research conducted over the past decade has increasingly linked obesity and inflammation; pro-inflammatory, classically activated M1 macrophage cells of the innate immune system infiltrate adipose tissue at the onset of weight gain contributing to the inflammatory state of fat, ultimately resulting in systemic insulin resistance, while alternatively activated, anti-inflammatory M2 macrophages safeguard insulin sensitivity in metabolic tissues. The mechanisms controlling macrophage subtype remain unclear and it is possible the type of energy substrates available to macrophages in the tissue microenvironment, or the ability of these cells to utilize specific substrates for fuel, may be one mechanism by which macrophage phenotype is modulated. Aim 1 of this proposal will explore how restricting fuel substrate availability affects macrophage subtype (i.e. pro- versus anti-inflammatory) through the use of a macrophage-specific glucose transporter 1 knockout mouse (Glut1 M¿-/-) and a high-fat feeding model of diet-induced obesity. Metabolic phenotyping, including body weight and composition, food intake and activity, systemic insulin sensitivity and glucose tolerance, and energy expenditure will be performed on lean and obese Glut1 M¿-/- and wildtype littermate controls. The degree of macrophage infiltration in epididymal white adipose tissue (eWAT), as well as macrophage subtype and modifications to the eWAT insulin signaling pathway, will be determined using a combination of histologic, gene and protein expression analyses. Lastly, the effect of macrophage phenotype on the eWAT microenvironment in total will be characterized through the use of genomic microarray analysis and metabolomic profiling. Obesity is considered an immune-suppressive state and the Centers for Disease Control and Prevention now recognize obesity as an independent risk factor for increased influenza morbidity and mortality. Aim 2 of this proposal will explore the relationship among obesity, macrophage phenotype and influenza infection and their joint influence over flu infection severity. The Glut1M¿-/- / diet-induced obesity model will be used as in Aim 1, with the addition o an influenza infection. Overall survival, lung pathology, viral clearance and immune cell population characterization will be completed. This project will afford an opportunity to work closely with, and be mentored by, a team of highly respected researchers in the public health fields of obesity and infectious disease. Completion of this research project will culminate in mastery of skills such as conducting controlled animal feeding studies, metabolic phenotyping, immune system characterization, and bioinformatic analyses of large genomic and metabolomics data sets, manuscript writing, data presentation, granstmanship and research project management.