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.

最近的人类流行病学证据表明空气污染与肥胖和代谢增加有关 人们对使用小鼠模型来识别潜在的潜在疾病引起了极大的兴趣 生物学机制。在这方面，有限的研究表明，暴露于浓缩环境中 在致胖饮食的背景下，颗粒物（PM）会增加肥胖和胰岛素抵抗。 此外，这些研究重点关注 PM2.5（空气动力学直径 S 2.5pm）并使用 仅具有一个暴露期的横断面研究设计。相比之下，涉及中枢神经的研究 系统表型采用了纳米级 PM（nPM；空气动力学直径 2 200 nm）， 研究显示它们可以进入大脑并发挥功能作用。尽管 PM2.5 和 nPM 都能可靠地诱发 组织中的氧化应激和炎症，nPM 具有与 儿童健康研究 (CHS) 中近道路空气污染 (NRAP) 与肥胖之间的关联 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 导致肥胖的原因尚不清楚。了解这些病理生理机制可能有助于 对保护人们免受当前和未来最大的空气污染影响的重要影响 忧虑。解决这些关键障碍。项目3将与成熟的技术进行综合实验 C57BL/6 肥胖小鼠模型，将结合出生时减少窝数（以诱导营养过剩） 断奶时采用高脂肪喂养。使用纵向研究设计，小鼠将 在产前暴露于新型近道路 NPM 源（暴露组）或过滤空气（对照组）， 产后，或产前和产后发育。小鼠将具有与肥胖相关的代谢特征， 5周龄（青春期）、9周龄时的分子、生化和神经生物学表型 （青春期后期）和 13 周龄（成年早期）。在具体目标 1 中，我们将确定身体 通过磁共振成像评估成分（瘦肉组织质量和全身脂肪），评估葡萄糖/胰岛素 通过腹膜内葡萄糖耐量试验（IPGTT）进行代谢，测量血浆中的一组脂肪细胞因子， 并测定肝脂质含量。在具体目标 2 中，我们将通过以下方式表征小鼠的脂肪组织： 免疫组织化学测定冠样结构 (CLS) 的存在，这表明 巨噬细胞浸润和炎症，并通过流式细胞术定量巨噬细胞亚型 (M1/M2)。 将进行外植体孵化研究以确定脂肪细胞因子的体外生产和实时 PCR 将用于研究分离的脂肪细胞和 巨噬细胞。在具体目标 3 中，我们将确定 nPM 暴露对肥胖的影响是否 通过下丘脑中控制代谢调节的神经生物学途径介导。 免疫组织化学技术和形态分析将用于表征组织 下丘脑神经投射参与摄食调节。代谢相关的表达 神经肽基因也将通过实时 PCR 和食物摄入以细胞核特异性方式进行研究 将进行评估以确定 nPM 暴露是否会导致进食行为改变。 总的来说，拟议的研究提供了几个层面的创新：（1）与中心一致 重点关注 NRAP，我们将使用在主要交通走廊附近收集的 nPM，并且我们之前已将其展示给 在体外和体内具有明显的生化和分子效应； (2) nPM反映邻近道路 嵌入在元素碳中的生物学相关的纳米级尺寸部分的梯度和 车用金属； (3)新颖的收集和曝光程序将保留尺寸分布 原始气溶胶以及此类 nPM 转移到体循环和进入体循环的已知潜力 器官，包括大脑； （4）肥胖小鼠模型反映了人类肥胖的自然生命历程 将生命早期的营养过剩与断奶时的高脂肪喂养结合起来； 5) 期间将动物暴露于 nPM 三个发育阶段将确定易感性的关键窗口。因此。项目3高 与该中心的其他项目相结合，并将通过阐明人类研究来补充人类研究 NRAP 对肥胖和代谢失调影响的病理生理机制。这 我们将在小鼠身上获得的生理表型，例如全身成分、葡萄糖耐量和 肝脏脂肪沉积，将与项目 1 获得的结果相当，该项目将研究 CHS 参与者 从终生暴露于空气污染的极端情况中选择。在以下水平获得的小鼠表型 脂肪组织的变化，包括组织学、脂肪细胞因子释放和细胞特异性基因表达，将相似于 相当于项目 2 中提出的从 CHS 受试者获得的结果。因此，实验 项目 3 中提出的建议将产生对影响的时间顺序和方向性的有意义的见解 nPM 对小鼠肥胖的三个重要方面进行研究，并可能提供指导的因果信息 项目 1 和 2 中进行了知情分析，因为在人类中收集了类似的肥胖相关参数。