Localization and regulation of metabolic gene expression in response to dietary triglycerides

饮食甘油三酯代谢基因表达的定位和调节

• 批准号: 10156411
• 负责人: Michelle Biederman
• 金额: $ 4.6万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-02-01 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10156411
• 关键词: Address; Animal Model; Animals; Apolipoproteins; Apolipoproteins B; Behavioral; Biological Assay; Cardiovascular Diseases; Cell Nucleus; Cell physiology; Cells; Cholesterol; Chylomicrons; Complex; Confocal Microscopy; Cultured Cells; Data; Dependence; Development; Diabetes Mellitus; Dietary Fats; Dietary Fatty Acid; Dietary Practices; Engineering; Enterocytes; Fatty Liver; Fatty acid glycerol esters; Fluorescence; Future; Gene Expression; Genes; Genetic; Genetic Transcription; Heart Diseases; High Fat Diet; Homeostasis; Human; Hydrophobicity; Individual; Inflammation; Insulin; Intestines; Knowledge; Larva; Lead; Link; Lipids; Lipoproteins; Liver; Location; Low-Density Lipoproteins; Measurement; Measures; Mediating; Membrane; Metabolic; Metabolic Diseases; Metabolic Pathway; Metabolism; Mus; Nutrient; Nutritional; Obesity; Optical reporter; Optics; Organ; Pathway interactions; Pharmacology; Phospholipids; Plasma; Production; Proteins; Regulation; Reporter; Research; Satiation; Signal Transduction; Site; Small Intestines; System; Techniques; Testing; Time; Tissues; Transgenic Organisms; Triglycerides; Very low density lipoprotein; Work; Zebrafish; absorption; apolipoprotein A-IV; body system; cell type; design; dietary; experimental study; feeding; gastrointestinal system; genomic locus; lipid metabolism; lipid transfer protein; microbial; microbiota; microsomal triglyceride transfer protein; mutant; overexpression; particle; response; screening; single-cell RNA sequencing; small molecule; spatiotemporal; tool; transcription factor; uptake; Address; Animal Model; Animals; Apolipoproteins; Apolipoproteins B; Behavioral; Biological Assay; Cardiovascular Diseases; Cell Nucleus; Cell physiology; Cells; Cholesterol; Chylomicrons; Complex; Confocal Microscopy; Cultured Cells; Data; Dependence; Development; Diabetes Mellitus; Dietary Fats; Dietary Fatty Acid; Dietary Practices; Engineering; Enterocytes; Fatty Liver; Fatty acid glycerol esters; Fluorescence; Future; Gene Expression; Genes; Genetic; Genetic Transcription; Heart Diseases; High Fat Diet; Homeostasis; Human; Hydrophobicity; Individual; Inflammation; Insulin; Intestines; Knowledge; Larva; Lead; Link; Lipids; Lipoproteins; Liver; Location; Low-Density Lipoproteins; Measurement; Measures; Mediating; Membrane; Metabolic; Metabolic Diseases; Metabolic Pathway; Metabolism; Mus; Nutrient; Nutritional; Obesity; Optical reporter; Optics; Organ; Pathway interactions; Pharmacology; Phospholipids; Plasma; Production; Proteins; Regulation; Reporter; Research; Satiation; Signal Transduction; Site; Small Intestines; System; Techniques; Testing; Time; Tissues; Transgenic Organisms; Triglycerides; Very low density lipoprotein; Work; Zebrafish; absorption; apolipoprotein A-IV; body system; cell type; design; dietary; experimental study; feeding; gastrointestinal system; genomic locus; lipid metabolism; lipid transfer protein; microbial; microbiota; microsomal triglyceride transfer protein; mutant; overexpression; particle; response; screening; single-cell RNA sequencing; small molecule; spatiotemporal; tool; transcription factor; uptake

Abstract: The metabolic response to meals high in fat and cholesterol requires the coordination of a complex system of cellular processes. Disruption of these cellular processes can lead to metabolic diseases, such as diabetes, heart disease, and hepatic steatosis. Previous experiments have shown that high-fat diets increase transcription of genes and gene pathways that mediate lipid metabolism, storage, and secretion. One of the most highly upregulated genes within the digestive organs (liver and small intestine), in response to dietary triglycerides (TG), is apolipoprotein A4 (apoa4). The function of ApoA4 protein is currently unknown, but it has been implicated in the regulation of lipoprotein particle synthesis and secretion, as well as satiety, inflammation, and insulin responsivity. Since TG-induced apoa4 gene expression has not been observed in cultured cells and only observed in whole animal models, I will use the zebrafish system to examine the spatial and temporal expression of lipid metabolic genes in response to dietary TG. The digestive system of zebrafish is functionally and developmentally similar to mammalian systems, with high genetic conservation in essential metabolic components. Because larval zebrafish are optically clear and genetically tractable, I have engineered a cell- tracing, fluorescent reporter in the endogenous apoa4 locus, which will allow me to visualize the dietary TG response in live zebrafish larvae. I plan to characterize the timing and location of apoa4 expression to determine whether expression of lipid metabolic genes is a cell-autonomous response to direct, cellular uptake of TGs; or if it is driven by short- and/or long-distance intercellular signaling. The proposed apoa4 reporter will also allow me to screen for the effect of specific pathway genes and transcription factors (TFs) on the TG-induced transcriptional response of intestinal enterocytes that results in apoa4 expression. I plan to use my apoa4 reporter as a measure of dietary TG absorption to help delineate the cellular mechanisms that underlie the dietary TG metabolic gene response. Although, several TFs implicated in regulating apoa4 have been identified in the liver, TFs responsible for regulating apoa4 in enterocytes have not been characterized. We know that lipoprotein synthesis and secretion in digestive organs is largely dependent on microsomal triglyceride transfer protein (MTP) activity, but the mechanisms underlying the dependence on MTP for apoa4 gene expression in different digestive organs is unknown. To determine the regulatory mechanisms underlying MTP-dependence in the intestine, I plan to use the apoa4 transgenic reporter to assay genes that potentially mediate the relationships between dietary TG absorption, MTP activity, and apoa4 expression. The proposed research will identify regulatory relationships between the metabolic gene response to dietary TGs, and lipoprotein production and secretion. Additionally, the proposed apoa4 optical reporter will be a valuable tool for rapid measurement of triglyceride absorption in response to changes in nutritional, behavioral, microbial, pharmacological, and environmental conditions in future studies.

摘要：对高脂肪和胆固醇的饮食的代谢反应需要配合 细胞过程系统。这些细胞过程的破坏会导致代谢疾病，例如 糖尿病，心脏病和肝脂肪变性。以前的实验表明高脂饮食增加 介导脂质代谢，储存和分泌的基因和基因途径的转录。中的一个 消化器官（肝脏和小肠）中最高度上调的基因，响应饮食 甘油三酸酯（TG）是载脂蛋白A4（APOA4）。 apoA4蛋白的功能目前尚不清楚，但它具有 与脂蛋白颗粒合成和分泌的调节以及饱腹感，炎症， 和胰岛素反应。由于在培养细胞和 仅在整个动物模型中观察到，我将使用斑马鱼系统检查空间和时间 脂肪代谢基因的表达响应饮食TG。斑马鱼的消化系统在功能上是 并且在发展上与哺乳动物系统相似，在基本代谢中具有很高的遗传保护 成分。由于幼虫斑马鱼在光学上清晰和遗传处理，所以我已经设计了一个细胞 跟踪内源性ApoA4基因座中的荧光记者，这将使我能够可视化饮食TG 活斑马鱼幼虫的反应。我计划表征ApoA4表达式的时间和位置以确定 脂质代谢基因的表达是否是对TGS的直接细胞摄取的细胞自主反应；或者 如果它是由短距和/或长距离界面间信号传导驱动的。 拟议的APOA4记者还将允许我筛选特定途径基因的影响和 TG诱导的肠肠上皮细胞转录因子（TF）导致TG诱导的转录反应 apoA4表达。我计划使用我的apoa4记者作为饮食TG吸收的量度，以帮助描述 饮食TG代谢基因反应的基础的细胞机制。虽然，有几个TF涉及 在肝脏中已经确定了调节APOA4，负责调节肠球菌中APOA4的TF尚未 被描述了。我们知道，消化器官中的脂蛋白合成和分泌在很大程度上取决于 在微粒体甘油三酸酯转移蛋白（MTP）上，但依赖性的机制 不同消化器官中ApoA4基因表达的MTP尚不清楚。确定监管 肠中MTP依赖性的机制，我计划使用ApoA4转基因记者进行测定 可能介导饮食TG吸收，MTP活性和APOA4之间关系的基因 表达。拟议的研究将确定代谢基因反应之间的调节关系 饮食中的TG，以及脂蛋白的产生和分泌。此外，拟议的apoa4光学报道将会 成为快速测量甘油三酸酯吸收的有价值的工具，以应对营养变化， 未来研究中的行为，微生物，药理和环境条件。