Role of cholesteryl ester transfer protein in cellular lipid homeostasis

胆固醇酯转移蛋白在细胞脂质稳态中的作用

基本信息

批准号：
8038750
负责人：
RICHARD E MORTON
金额：
$ 39.25万
依托单位：
CLEVELAND CLINIC LERNER COM-CWRU
依托单位国家：
美国
项目类别：
财政年份：
2000
资助国家：
美国
起止时间：
2000-02-25 至 2014-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8038750
关键词：
Acute Adipocytes Adipose tissue Affect Alternative Splicing Amino Acids Applications Grants Atherosclerosis Biochemical Biological Process Cell Culture Techniques Cell physiology Cell secretion Cells Cholesterol Cholesterol Ester Transfer Proteins Cholesterol Esters Cholesterol Homeostasis Cytoplasm Data Deposition Development Disease Endoplasmic Reticulum Enterocytes Exons Extrahepatic Failure Fatty acid glycerol esters Generations Genetic Hamsters Heart Diseases Hepatocyte Homeostasis Hormones In Vitro Inflammation Inflammatory Response Insulin Resistance Intestines Kinetics Learning Length Link Lipids Lipoproteins Liver Measures Mediating Messenger RNA Metabolic Metabolism Microscopy Microsomes Mining Molecular Movement Organelles Pathway interactions Pharmaceutical Preparations Plasma Play Process Protein Biosynthesis Protein Deficiency Protein Inhibition Protein Isoforms Protein Overexpression Proteins Regulation Role Site Structure Techniques Testing Tissues Triglycerides Variant absorption adipokines atherogenesis cell type density glucose metabolism in vivo insight lipid metabolism lipid transport novel protein expression protein metabolism protein structure protein transport sugar

项目摘要

DESCRIPTION (provided by applicant): Cholesteryl ester transfer protein (CETP) exchanges cholesteryl ester (CE) and triglyceride (TG) between lipoproteins and is well recognized as a regulator of plasma lipoprotein metabolism. CETP also resides inside cells where two isoforms exist: full-length (FL) and exon 9 (E9)-deleted CETP. The function of CETP inside cells is not understood, but it is clearly essential since inhibiting CETP biosynthesis in adipocytes impairs lipid storage. We postulate this occurs because intracellular CETP is required for CE and TG transport from their site of synthesis to their site of storage. To test this general hypothesis, we propose three specific aims. Aim 1 - Determine the CETP isoform(s) that promote cellular lipid storage, and define the structural features of CETP that are essential to its intracellular function. This aim tests the hypothesis that E9-deleted CETP facilitates intracellular lipid transport directly or by interacting with FL CETP, and also examines how this cellular activity depends on CETP structure. Aim 2 - Define the role of CETP in cellular lipid metabolism. To unravel the mechanisms by which CETP deficiency disrupts cellular lipid metabolism, this aim quantifies metabolic alterations and defines changes in lipid droplet formation that occur when CETP isoform expression is altered. Aim 3 - Define the role of CETP in the formation and utilization of lipid storage droplets in lipoprotein- synthesizing cells. Consistent with preliminary studies, we propose that in lipoprotein-synthesizing cells CETP assists in both lipid droplet formation and the reverse transport of stored lipids to microsomes for lipoprotein assembly. Genetic and adenoviral approaches will alter expression of FL and/or E9-deleted CETPs in SW872 adipocytes, Caco-2 intestinal enterocytes, and in hamster. The consequences of these molecular manipulations on lipid synthesis, interorganelle lipid transport, lipid droplet formation and lipoprotein assembly will be studied through biochemical and microscopy techniques. These studies will describe a novel function for CETP and advance our understanding of cellular lipid transport and storage mechanisms. Lipid storage in adipocytes is linked to their secretion of hormones that regulate glucose and lipid metabolism, which directly affect processes such as inflammation and atherogenesis. PUBLIC HEALTH RELEVANCE: This grant application focuses on cholesteryl ester transfer protein - a protein that may transport fat inside of cells so that these lipids can be efficiently stored and retrieved when needed. Fat storage is a key function of many cells, but especially in adipose tissue where the amount of fat stored alters the secretion of important hormones that influence the body's use of fat and sugar for energy, and effect the development of insulin resistance and heart disease.

描述（由申请人提供）：胆固醇酯转移蛋白（CETP）在脂蛋白之间交换胆固醇酯（CE）和甘油三酯（TG），并且被广泛认为是血浆脂蛋白代谢的调节剂。 CETP 还存在于存在两种亚型的细胞内：全长 (FL) 和外显子 9 (E9) 删除的 CETP。 CETP 在细胞内的功能尚不清楚，但它显然是必需的，因为抑制脂肪细胞中的 CETP 生物合成会损害脂质储存。我们假设发生这种情况是因为细胞内 CETP 是 CE 和 TG 从合成位点运输到储存位点所必需的。为了检验这个一般假设，我们提出了三个具体目标。目标 1 - 确定促进细胞脂质储存的 CETP 亚型，并定义对其细胞内功能至关重要的 CETP 结构特征。该目的测试了以下假设：E9 缺失的 CETP 直接或通过与 FL CETP 相互作用促进细胞内脂质转运，并检查了这种细胞活性如何依赖于 CETP 结构。目标 2 - 定义 CETP 在细胞脂质代谢中的作用。为了揭示 CETP 缺乏破坏细胞脂质代谢的机制，该目标量化了代谢改变并定义了当 CETP 同工型表达改变时发生的脂滴形成的变化。目标 3 - 定义 CETP 在脂蛋白合成细胞中脂质储存液滴的形成和利用中的作用。与初步研究一致，我们提出，在脂蛋白合成细胞中，CETP 有助于脂滴形成和将储存的脂质逆向转运至微粒体以进行脂蛋白组装。遗传和腺病毒方法将改变 SW872 脂肪细胞、Caco-2 肠细胞和仓鼠中 FL 和/或 E9 删除的 CETP 的表达。这些分子操作对脂质合成、细胞器间脂质转运、脂滴形成和脂蛋白组装的影响将通过生化和显微镜技术进行研究。这些研究将描述 CETP 的新功能，并增进我们对细胞脂质运输和储存机制的理解。脂肪细胞中的脂质储存与其分泌调节葡萄糖和脂质代谢的激素有关，这直接影响炎症和动脉粥样硬化等过程。公共健康相关性：这项拨款申请的重点是胆固醇酯转移蛋白——一种可以在细胞内运输脂肪的蛋白质，以便在需要时可以有效地储存和检索这些脂质。脂肪储存是许多细胞的关键功能，尤其是在脂肪组织中，储存的脂肪量会改变重要激素的分泌，从而影响人体利用脂肪和糖获取能量，并影响胰岛素抵抗和心脏病的发展。