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

• 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
• 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

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汁脂酯（CE）和甘油三酸酯（TG），并且被广泛认为是血浆脂蛋白代谢的调节剂。 CETP还位于存在两个同工型的细胞内：全长（FL）和外显子9（E9）删除CETP。 CETP内部细胞内部的功能尚不清楚，但显然是必不可少的，因为抑制脂肪细胞中CETP生物合成会损害脂质储存。我们认为这是因为CE和TG从其合成部位转移到其存储部位所需的细胞内CETP。为了检验这一普遍的假设，我们提出了三个具体目标。 AIM 1-确定促进细胞脂质储存的CETP同工型，并定义CETP的结构特征，这对于其细胞内功能至关重要。该目标检验了E9删除的CETP的假设可直接或通过与FL CETP相互作用，并研究了该细胞活性如何取决于CETP结构。 AIM 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，此目标可以量化新陈代谢的改变，并定义当CETP同工型表达改变时发生的脂质液滴形成的变化。 AIM 3-定义CETP在脂质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有助于脂质液滴形成和储存的脂质向微体质的反向转运以进行脂蛋白组装。遗传和腺病毒方法将改变SW872脂肪细胞，CACO-2肠肠细胞和仓鼠中FL和/或E9删除CETP的表达。这些分子操作对脂质合成，脂质间脂质转运，脂质液滴的形成和脂蛋白组装的后果将通过生化和显微镜技术研究。这些研究将描述CETP的新功能，并促进我们对细胞脂质转运和存储机制的理解。脂肪细胞中的脂质储存与调节葡萄糖和脂质代谢的激素的分泌有关，这些激素直接影响炎症和动脉粥样硬化的过程。 公共卫生相关性：该赠款应用的重点是胆固醇酯转移蛋白 - 一种可能在细胞内部输送脂肪的蛋白质，因此可以在需要时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，但尤其是在脂肪组织中，脂肪存储的量会改变影响人体使用脂肪和糖来能量的重要激素的分泌，并影响胰岛素抵抗和心脏病的发展。