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 脂肪代谢紊乱，如肥胖、代谢综合征和动脉粥样硬化，其特征是 脂肪酸的异常加工。磷脂中脂肪酸的非随机分布，其中 饱和链连接到第一个(sn-1)碳，而不饱和链连接到第二个(sn-2)碳 甘油基团的原子，对膜结构、脂代谢和第二 Messenger功能正常。然而，在控制sn-2位不饱和脂肪酸组成的同时， 通过Lands途径，目前还不清楚是什么控制了sn-1位置的饱和脂肪酸。我们有 收集的初步数据有力地表明了sn-1特异性的饱和重塑途径 脂肪酸，它在脂蛋白的产生中起着关键作用。根据我们的初步数据，我们 假设酰基转移酶LPGAT1控制着两种最常见的 丰富的磷脂、磷脂酰乙醇胺(PE)和磷脂酰胆碱(PC)，这一途径 对肝细胞内脂质从头合成的调控起关键作用。来检验我们的假设并 确定LPGAT1的功能，我们将(I)建立LPGAT1重塑磷脂的机制 (2)确定LPGAT1在脂质从头合成中的调节作用。为此，我们将定义 LPGAT1的体外酶反应对该酶(亚目的1a)的表达和纯化，测定 LPGAT1基因敲除和敲除对亚细胞膜脂质组成的影响 组织和细胞器的脂质组学分析(亚目的1b)，剖析LPGAT1的重塑途径 示踪同位素标记底物的代谢并通过重建脱酰-反应循环 (次级目标1c)，通过同位素标记研究确定LPGAT1重塑PC的机制 肝细胞(亚目的1D)，确定LPGAT1如何通过脂质体范围的13C-1影响小鼠的全局脂质通量 通量组学分析(亚目的2a)；确定LPGAT1消融对脂蛋白代谢的影响 检测小鼠脂蛋白的产生和清除(亚目的2b)，并确定LPGAT1 消融对低密度脂蛋白受体缺陷小鼠动脉粥样硬化的保护作用(亚目的2c)。建议的工作是 意义重大，因为(I)它将建立一个与土地周期平行的概念，用于重塑 Sn-1位置的饱和脂肪酸和(Ii)它将识别这一途径在脂质中的功能 新陈代谢网络。预计这将对磷脂概念的演变产生关键影响 重塑并与普遍的健康问题直接相关，如肥胖、代谢综合征和 动脉硬化。