Towards investigating apolipoprotein E genotypes on the metabolism of long chain fatty acids

研究载脂蛋白E基因型对长链脂肪酸代谢的影响

• 批准号: 418577-2012
• 负责人: Plourde, Mélanie
• 金额: $ 2.19万
• 依托单位: Université de Sherbrooke
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=596418
• 关键词: Towards; investigating; apolipoprotein; genotypes; metabolism

Long-chain polyunsaturated fatty acids (LC-PUFA) are provided almost exclusively by the diet. They are important to maintain the physical nature of cell membranes and induce gene expression or repression in many different cell types. LC-PUFA are mainly delivered to organs by circulating lipoproteins that contains apolipoprotein E (APOE) protein. There are three existing isoforms of this protein in human namely APOE2, APOE3 and APOE4. We have recently shown in humans carriers of APOE4 that there are imbalances in the distribution of LC-PUFA in plasma total lipids. These imbalances potentially deregulate the cellular content in LC-PUFA and hence induce dysfunctions in gene expression or repression. Since APOE is expressed in many different types of cells, transgenic mice knock-in for human APOE genotypes provide unique tools to study the cellular source-dependant role of APOE isoforms in LC-PUFA homeostasis. Therefore, our objective is to elucidate the role(s) of APOE genotypes on LC-PUFA metabolism and gene expression or repression. To do so, we will use transgenic mice carrying human APOE2, APOE3 or APOE4 genotype. In our first experiment, we will use three carbon 13 non-radioactive fatty acids (tracers) to monitor precisely the metabolism of these fatty acids over one month. In our second experiment, we will feed the mice one of the four following diets: A) a control diet, B) a diet enriched in omega-3 LC-PUFA, C) a diet deprived in omega-3 LC-PUFA and other omega-3 fatty acids and D) a high-fat diet that will produce human-like lipoprotein levels. Because these diets will change the cellular content of organs such as liver, heart and white adipose tissue, we will quantify the cellular content in LC-PUFA and quantify the expression of fatty acid transporters and fatty acid receptor genes and quantify their respective protein levels. This work will contribute to better understand how one specific gene-by-diet interaction (LC-PUFA by APOE genotypes) change the whole body homeostasis in LC-PUFA. This is an important question to investigate considering the regulatory role of LC-PUFA in the cells.

长链多不饱和脂肪酸（LC-PUFA）几乎完全由饮食提供。它们对于维持细胞膜的物理性质和诱导许多不同细胞类型中的基因表达或抑制是重要的。LC-PUFA主要通过含有载脂蛋白E（APOE）蛋白的循环脂蛋白递送到器官。该蛋白在人体内存在三种亚型，即APOE 2、APOE 3和APOE 4。我们最近在APOE 4携带者中发现，血浆总脂质中LC-PUFA的分布不平衡。这些不平衡可能使LC-PUFA中的细胞内容物失调，从而诱导基因表达或抑制功能障碍。由于APOE在许多不同类型的细胞中表达，转基因小鼠敲入人类APOE基因型提供了独特的工具来研究LC-PUFA稳态中APOE亚型的细胞来源依赖性作用。因此，我们的目标是阐明载脂蛋白E基因型对LC-PUFA代谢和基因表达或抑制的作用。为此，我们将使用携带人APOE 2、APOE 3或APOE 4基因型的转基因小鼠。在我们的第一个实验中，我们将使用三种碳13非放射性脂肪酸（示踪剂）来精确监测这些脂肪酸在一个月内的代谢。在我们的第二个实验中，我们将给小鼠喂食以下四种饮食中的一种：A）对照饮食，B）富含ω-3 LC-PUFA的饮食，C）缺乏ω-3 LC-PUFA和其他ω-3脂肪酸的饮食，和D）将产生类人脂蛋白水平的高脂肪饮食。由于这些饮食会改变肝脏、心脏和白色脂肪组织等器官的细胞含量，我们将对LC-PUFA中的细胞含量进行定量，并对脂肪酸转运蛋白和脂肪酸受体基因的表达进行定量，并对它们各自的蛋白水平进行定量。这项工作将有助于更好地了解一个特定的基因与饮食的相互作用（LC-PUFA与APOE基因型）如何改变LC-PUFA的全身稳态。考虑到LC-PUFA在细胞中的调节作用，这是一个重要的研究问题。