The Function of Mammalian LPGAT1

哺乳动物LPGAT1的功能

• 批准号: 10563280
• 负责人: M Mahmood Hussain
• 金额: $ 51.66万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-02-10 至 2027-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10563280
• 关键词: Ablation; Acyl Coenzyme A; Acylation; Acyltransferase; Address; Affect; Atherosclerosis; Biochemical Pathway; Biochemical Reaction; Biological Process; Body fat; Carbon; Chemicals; Collaborations; Data; Disease; Enzymes; Fatty Acids; Glycerol; Health; Hepatic; Hepatocyte; Human; In Vitro; Isotope Labeling; Knock-out; Knowledge; Laboratories; Lecithin; Link; Lipids; Lipoproteins; Low Density Lipoprotein Receptor; Mass Spectrum Analysis; Measures; Membrane; Metabolic syndrome; Metabolism; Methods; Methylation; Modeling; Modification; Mus; Obesity; Organelles; Palmitates; Pathway interactions; Phosphatidylethanolamine; Phospholipase A2; Phospholipids; Play; Positioning Attribute; Production; Public Health; Regulation; Resolution; Role; Saturated Fatty Acids; Second Messenger Systems; Specificity; Stearates; Testing; Time; Tissues; Unsaturated Fatty Acids; Vertebral column; Work; deacylation; experience; knock-down; lipid biosynthesis; lipid metabolism; lipidome; lipidomics; novel; reconstitution; stearoyl-coenzyme A; tool

Project Summary/Abstract Disorders of fat metabolism, such as obesity, metabolic syndrome, and atherosclerosis, are characterized by abnormal processing of fatty acids. The non-random distribution of fatty acids in phospholipids, where saturated chains are linked to the first (sn-1) but unsaturated chains are linked to the second (sn-2) carbon atom of the glycerol group, has important implications for membrane structure, lipid metabolism, and second messenger functions. However, while the composition of unsaturated fatty acids in sn-2 position is controlled by the Lands pathway, it has remained unclear what controls saturated fatty acids in sn-1 position. We have collected preliminary data that strongly suggest an sn-1 specific remodeling pathway for saturated fatty acids, which plays a pivotal role in the production of lipoproteins. Based on our preliminary data we postulate that the acyltransferase LPGAT1 controls the composition of saturated fatty acids in the two most abundant phospholipids, phosphatidylethanolamine (PE) and phosphatidylcholine (PC), and that this pathway is critical for the regulation of the de novo synthesis of lipids in hepatocytes. To test our hypothesis and to identify the function of LPGAT1, we will (i) establish the mechanism of phospholipid remodeling by LPGAT1 and (ii) establish the regulatory function of LPGAT1 in lipid de novo synthesis. To this end, we will define the enzymatic reaction of LPGAT1 in vitro upon expression and purification of the enzyme (subaim 1a), determine the effect of LPGAT1 knockout and knockdown on the lipid composition of subcellular membranes by lipidomics analysis of tissues and organelles (subaim 1b), dissect the remodeling pathway of LPGAT1 by tracing the metabolism of isotope-labeled substrates and by reconstituting the deacylation-reacylation cycle (subaim 1c), determine the mechanism by which LPGAT1 remodels PC by isotope labeling studies in hepatocytes (subaim 1d), determine how LPGAT1 affects global lipid fluxes in mice by lipidome-wide 13C- fluxomics analysis (subaim 2a); determine the effect of LPGAT1 ablation on lipoprotein metabolism by measuring production and clearance of lipoproteins in mice (subaim 2b), and establish whether LPGAT1 ablation protects from atherosclerosis in LDL-receptor deficient mice (subaim 2c). The proposed work is significant because (i) it will establish a parallel concept to the Lands cycle for the remodeling of saturated fatty acids in sn-1 position and (ii) it will identify the function of this pathway within the lipid metabolic network. This is expected to have critical influence on the evolving concepts of phospholipid remodeling and be directly relevant to prevalent health problems, such as obesity, metabolic syndrome, and atherosclerosis.

项目摘要/摘要 脂肪代谢疾病（例如肥胖，代谢综合征和动脉粥样硬化）的特征是 脂肪酸的异常加工。磷脂中脂肪酸的非随机分布，其中 饱和链与第一个（SN-1）有关，但不饱和链与第二个（SN-2）碳链接 甘油组的原子对膜结构，脂质代谢和第二 Messenger功能。但是，控制不饱和脂肪酸在SN-2位置的组成。 通过土地途径，尚不清楚哪些控制饱和脂肪酸在SN-1位置。我们有 收集的初步数据强烈建议SN-1特异性重塑途径 脂肪酸在脂蛋白的产生中起关键作用。根据我们的初步数据 假设酰基转移酶LPGAT1控制两者中饱和脂肪酸的组成 丰富的磷脂，磷脂酰乙醇胺（PE）和磷脂酰胆碱（PC），并且该途径 对于调节肝细胞中脂质的从头合成至关重要。检验我们的假设和 确定LPGAT1的功能，我们将（i）通过LPGAT1建立磷脂重塑的机理 （ii）在从头合成中建立LPGAT1的调节功能。为此，我们将定义 LPGAT1在表达和纯化酶（Subaim 1a）后体外的酶促反应，确定 LPGAT1敲除和敲除对亚细胞膜脂质组成的影响 组织和细胞器（Subaim 1B）的脂质分析分析，通过LPGAT1的重塑途径通过 追踪同位素标记的底物的代谢，并通过重新建立脱酰二酰化循环 （Subaim 1C），确定LPGAT1通过同位素标记研究中的PC的机制 肝细胞（Subaim 1D），确定LPGAT1如何通过全脂肪组13C- 通量分析（Subaim 2a）；确定LPGAT1消融对脂蛋白代谢的影响 测量小鼠（Subaim 2b）中脂蛋白的产生和清除，并确定LPGAT1是否是 消融可保护LDL受体缺陷小鼠的动脉粥样硬化（Subaim 2c）。拟议的工作是 意义重大，因为（i）它将建立与土地周期的平行概念，以重塑 饱和脂肪酸位于SN-1位置，（ii）将确定该途径在脂质内的功能 代谢网络。预计这将对磷脂不断发展的概念产生关键影响 重塑并与普遍的健康问题直接相关，例如肥胖，代谢综合征和 动脉粥样硬化。