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.

项目概要/摘要 脂肪代谢紊乱，如肥胖、代谢综合征和动脉粥样硬化，其特点是 脂肪酸加工异常。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)，但不饱和链连接到第二个 (sn-2) 碳 甘油基团的原子，对膜结构、脂质代谢和第二方面具有重要意义 信使功能。然而，虽然控制了sn-2位不饱和脂肪酸的组成 通过 Lands 途径，目前尚不清楚是什么控制着 sn-1 位置的饱和脂肪酸。我们有 收集的初步数据强烈表明饱和的 sn-1 特定重塑途径 脂肪酸，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 控制着两个最重要的饱和脂肪酸的组成 丰富的磷脂、磷脂酰乙醇胺（PE）和磷脂酰胆碱（PC），并且该途径 对于肝细胞中脂质从头合成的调节至关重要。为了检验我们的假设并 确定LPGAT1的功能后，我们将（i）建立LPGAT1磷脂重构的机制 (ii) 建立 LPGAT1 在脂质从头合成中的调节功能。为此，我们将定义 LPGAT1 在酶表达和纯化后的体外酶促反应 (subaim 1a)，确定 LPGAT1敲除和敲低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 (subaim 1b)，通过以下方式剖析 LPGAT1 的重塑途径 追踪同位素标记底物的代谢并重建脱酰基-再酰基化循环 (subaim 1c)，通过同位素标记研究确定 LPGAT1 重塑 PC 的机制 肝细胞 (subaim 1d)，通过脂质组范围 13C- 确定 LPGAT1 如何影响小鼠的整体脂质通量 通量组学分析（subaim 2a）；确定 LPGAT1 消融对脂蛋白代谢的影响 测量小鼠脂蛋白的产生和清除 (subaim 2b)，并确定 LPGAT1 是否 消融可以保护 LDL 受体缺陷小鼠免受动脉粥样硬化 (subaim 2c)。拟议的工作是 意义重大，因为 (i) 它将建立一个与土地循环平行的概念，用于改造 sn-1 位置的饱和脂肪酸，并且 (ii) 它将识别脂质内该途径的功能 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，例如肥胖、代谢综合征和 动脉粥样硬化。