Project 3: Longitudinal Effects of Air Pollution on Obesity in Mice (Allayee)

项目3：空气污染对小鼠肥胖的纵向影响（Allayee）

• 批准号: 8690062
• 负责人: Hooman Allayee
• 金额: $ 17.03万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8690062
• 关键词: Address; Adipocytes; Adipose tissue; Adolescence; Adverse effects; Aerosols; Affect; Age; Air Pollution; Animals; Architecture; Biochemical; Biological; Biological Markers; Biology; Birth; Blood Circulation; Blood Vessels; Body Composition; Body fat; Brain; C57BL/6 Mouse; Caliber; California; Carbon; Cell Nucleus; Cells; Child; Child health care; Collection; Complement; Control Groups; Coupling; Cross-Sectional Studies; Dental crowns; Deposition; Development; Diet; Eating; Epidemiology; Exposure to; Fatty acid glycerol esters; Feeding behaviors; Flow Cytometry; Future; Gene Expression; Glucose; Glucose tolerance test; Health; Hepatic; Histology; Homeostasis; Human; Hypothalamic structure; Immunohistochemistry; In Vitro; Infiltration; Inflammation; Inflammatory; Insulin; Insulin Resistance; Lead; Life; Life Cycle Stages; Link; Lipids; Longitudinal Studies; Magnetic Resonance Imaging; Measures; Mediating; Metabolic; Metabolic Control; Metabolic Diseases; Metabolism; Metals; Molecular; Mus; Neuraxis; Neurobiology; Neuropeptide Gene; Obesity; Organ; Overnutrition; Oxidative Stress; Participant; Particulate Matter; Pathway interactions; Phenotype; Physiological; Plasma; Population; Predisposition; Procedures; Production; Puberty; Regulation; Research Design; Source; Staging; Structure; Study Subject; Techniques; Time; Tissues; Weaning; air filter; blood glucose regulation; design; feeding; glucose tolerance; in vivo; innovation; insight; interest; intraperitoneal; macrophage; mouse model; nanoscale; novel; nutrition; obesity in children; particle; pollutant; postnatal; prenatal; relating to nervous system; research study; trafficking; young adult

Recent epidemiological evidence in humans linking air pollution with increased adiposity and metabolic diseases has garnered considerable interest in the use of mouse models to identify potential underlying biological mechanisms. In this regard, limited studies have shown that exposure to concentrated ambient particulate matter (PM) increases adiposity and insulin resistance in the context of an obesogenic diet. Furthermore, these studies have focused on PM2.5 (aerodynamic diameter S 2.5pm) and been done using cross-sectional study designs with only one exposure period. By comparison, studies involving central nervous system phenotypes have employed nanoscale PM (nPM; aerodynamic diameter 2 200nm), which have been shown to enter the brain where they have functional effects. Although both PM2.5 and nPM reliably induce oxidative stress and inflammation in tissues, nPM have steep near-roadway gradients corresponding to the associations between near-roadway air pollution (NRAP) and obesity in the Children's Health Study (CHS) described in Project 1. Despite these associations, the sequence of metabolic and/or inflammatory changes that lead to obesity are not known. Understanding these pathophysiological mechanisms could thus have important implications for protecting the population from air pollution exposures of greatest current and future concern. To address these critical barriers. Project 3 will carry out comprehensive experiments with the wellestablished C57BL/6 mouse model of obesity and will combine litter reduction at birth (to induce over-nutrition dunng early life) with high fat feeding at the time of weaning. Using a longitudinal study design, mice will be exposed to a novel near-roadway source of nPM (exposed group) or filtered air (control group) dunng prenatal, postnatal, or both pre and postnatal development. Mice will be characterized for obesity-related metabolic, molecular, biochemical, and neurobiological phenotypes at 5 weeks of age (puberty period), 9 weeks of age (late adolescence), and 13 weeks of age (young adulthood). In Specific Aim 1, we will determine body composition (lean tissue mass and whole body fat) by magnetic resonance imaging, assess glucose/insulin metabolism by intraperitoneal glucose tolerance tests (IPGTTs), measure a panel of adipocytokines in plasma, and determine hepatic lipid content. In Specific Aim 2, we will characterize adipose tissue from mice by immunohistochemistry to determine the presence of crown-like structures (CLS), which is indicative of macrophage infiltration and inflammation, and by flow cytometry to quantitate macrophage subtypes (M1/M2). Explant incubation studies will be carried out to determine in wfro production of adipocytokines and real-time PCR will be used to investigate inflammatory and metabolic gene expression in both isolated adipocytes and macrophages. In Specific Aim 3, we will determine whether the effects of nPM exposure on obesity are mediated through neurobiological pathways in the hypothalamus that control metabolic regulation. Immunohistochemical techniques and morphometric analyses will be used to characterize the organization of hypothalamic neural projections involved in feeding regulation. Expression of metabolically-relevant neuropeptide genes will also be investigated in a nucleus-specific manner by real-time PCR and food intake will be assessed to determine whether nPM exposure results in altered feeding behavior. Taken together, the proposed studies offer several levels of innovation: (1) consistent with the Center focus on NRAP, we will use nPM collected near a major traffic corridor and which we have previously shown to have demonstrable biochemical and molecular effects in vitro and in vivo; (2) the nPM reflects the nearroadway gradient in the biologically relevant nanoscale size fraction that is ennched in elemental carbon and metals of vehicular source; (3) the novel collection and exposure procedure will preserve the size distnbution of the original aerosol and the known potential of such nPM to translocate into the systemic circulation and into organs, including the brain; (4) the mouse model of obesity reflects the natural life course of obesity in humans by coupling over-nutrition in early life with high fat feeding at weaning; and 5) exposing animals to nPM during three developmental stages will identify critical window(s) of susceptibility. As a result. Project 3 is highly integrated with the other projects of this Center and will complement the human studies by elucidating the pathophysiological mechanisms that underlie the effects of NRAP on obesity and metabolic dysregulation. The physiological phenotypes that we will obtain in mice, such as whole body composition, glucose tolerance, and hepatic fat deposition, will be comparable to those obtained by Project 1, which will study CHS participants selected from the extremes of lifetime exposure to air pollution. The murine phenotypes obtained at the levels of adipose tissue, including histology, adipocytokine release, and cell-specific gene expression, will similarty be equivalent to those being obtained from CHS subjects as proposed in Project 2. Thus, the experiments proposed in Project 3 will yield meaningful insight into the temporal sequence and directionality of the effects of nPM on three important aspects of obesity in mice and may provide causal information that could guide informed analyses in Projects 1 and 2, as analogous obesity-related parameters are collected in humans.

人类最近的流行病学证据，将空气污染与肥胖和代谢增加联系起来 疾病对使用鼠标模型来识别潜在潜在的潜力引起了极大的兴趣 生物学机制。在这方面，有限的研究表明，暴露于集中的环境 在肥胖饮食的背景下，颗粒物（PM）会增加肥胖和胰岛素抵抗。 此外，这些研究集中于PM2.5（空气动力学直径S 2.5pm），并使用 横断面研究设计只有一个暴露期。相比之下，涉及中枢神经的研究 系统表型已使用纳米级PM（NPM；空气动力学直径为2 200nm）， 显示出具有功能效应的大脑。尽管PM2.5和NPM可靠地诱导 NPM在组织中的氧化应激和炎症中具有陡峭的近距离梯度，与对应 儿童健康研究（CHS）中近距离空气污染（NRAP）与肥胖之间的关联 在项目1中描述。尽管有这些关联，但代谢和/或炎症变化的顺序 导致肥胖症的原因尚不清楚。因此，了解这些病理生理机制可能具有 保护人口免受最新当前和未来的空气污染暴露的重要意义 忧虑。解决这些关键障碍。项目3将对良好的实验进行全面的实验 C57BL/6肥胖模型，将在出生时结合减少垃圾（诱导过度营养 发现断奶时的高脂进食。使用纵向研究设计，小鼠将是 暴露于新型NPM（暴露组）或过滤空气（对照组）dunng产前的近路源。 产后或产后发展。小鼠将以肥胖相关的代谢为特征， 5周龄（青春期），9周龄的分子，生化和神经生物学表型 （青春期晚期）和13周龄（成年年轻）。在特定目标1中，我们将确定身体 通过磁共振成像组成（瘦组织质量和全身脂肪），评估葡萄糖/胰岛素 腹膜内葡萄糖耐受性测试（IPGTTS）的代谢，测量血浆中脂肪细胞因子的面板， 并确定肝脂质含量。在特定的目标2中，我们将以小鼠的脂肪组织来表征 免疫组织化学确定存在冠状结构（CLS）的存在，这表明 巨噬细胞浸润和炎症，并通过流式细胞仪来定量巨噬细胞亚型（M1/M2）。 将进行外植体孵育研究以确定脂肪细胞的WFRO产生和实时 PCR将用于研究分离的脂肪细胞和 巨噬细胞。在特定目标3中，我们将确定NPM暴露对肥胖的影响是否是 通过控制代谢调节的下丘脑中的神经生物学途径介导。 免疫组织化学技术和形态计量分析将用于表征 下丘脑神经预测涉及进食调节。代谢相关的表达 神经肽基因也将通过实时PCR和食物摄入以核特异性方式研究 将评估以确定NPM暴露是否会导致进食行为改变。 综上所述，拟议的研究提供了几个级别的创新：（1）与中心一致 专注于NRAP，我们将使用在主要交通走廊附近收集的NPM，以前已显示 在体外和体内具有可证明的生化和分子效应； （2）NPM反映了近距离 在元素碳和 车辆来源的金属； （3）新颖的收集和曝光程序将保留大小的散布 原始的气溶胶和这种NPM的已知潜力转移到系统性循环中并进入 器官，包括大脑； （4）肥胖的老鼠模型反映了人类肥胖的自然生活过程 通过将早期的过度良好结合到断奶时的高脂进食； 5）在期间将动物暴露于NPM 三个发展阶段将确定易感性的关键窗口。因此。项目3高度高 与该中心的其他项目集成在一起，并将通过阐明人类研究 NRAP对肥胖和代谢失调的影响的病理生理机制。这 我们将在小鼠中获得的生理表型，例如全身成分，葡萄糖耐受性和 肝脂肪沉积将与项目1获得的肝脂肪沉积相媲美，该项目将研究CHS参与者 从终生暴露于空气污染的极端中选择。在水平上获得的鼠表型 脂肪组织的脂肪组织，包括组织学，脂肪细胞因子释放和细胞特异性基因表达，将同样 相当于项目2中提出的从CHS受试者获得的那些。因此，实验 项目3中提出的将产生对时间顺序和方向性的有意义的见解。 NPM在小鼠肥胖的三个重要方面，可能会提供可能指导的因果信息 在项目1和2中进行了知情分析，因为在人类中收集了与肥胖相关的类似参数。