The Role of MTP in Lipid Droplet Formation in Adipocytes

MTP 在脂肪细胞脂滴形成中的作用

基本信息

  • 批准号:
    8244930
  • 负责人:
  • 金额:
    --
  • 依托单位:
  • 依托单位国家:
    美国
  • 项目类别:
  • 财政年份:
    2011
  • 资助国家:
    美国
  • 起止时间:
    2011-04-01 至 2015-06-30
  • 项目状态:
    已结题

项目摘要

DESCRIPTION (provided by applicant): Our laboratory recently discovered that microsomal triglyceride transfer protein (MTP), a protein essential for the assembly of triglyceride-rich lipoproteins within hepatocytes and enterocytes, is expressed in adipocytes of mice, rats, and humans. In addition, MTP is expressed in 3T3-L1 cells, and expression increases ~5-fold when these cells are induced to differentiate into adipocytes. MTP is present in a punctate pattern on the surface of lipid droplets and is especially prominent at the points of contact of adjacent lipid droplets. When MTP expression is silenced and the cells induced to differentiate, only very small (<1 5m) lipid droplets are formed. In addition, when MTP is transfected into CHO cells and lipid droplet formation stimulated, larger droplets are formed compared to those formed in cells without MTP. Finally, knocking down MTP expression in mouse adipose tissue using Cre-Lox approaches leads to decreased adiposity and a leaner mouse than littermate controls. Our working hypothesis is: MTP is a critical component in the maturation and expansion of lipid droplets within the adipocyte. This working hypothesis will be tested as follows: Specific Aim 1: To define the requirement for MTP in lipid droplet maturation. These studies will test the hypotheses that MTP facilitates normal lipid droplet expansion and growth and that the absence of MTP in adipocytes in vivo results in leaner mice with reduced body fat and improved glucose metabolism. Using primary pre-adipocytes isolated from fat specific MTP-knockdown mice and 3T3-L1 cells, in which MTP expression has been silenced by siRNA, we will evaluate the effects of MTP deficiency on differentiation, lipid droplet formation and maturation, de novo lipogenesis, and glycerol metabolism. We will also explore the effects of enhanced MTP expression on lipid droplet formation and maturation in primary pre-adipocytes and 3T3 cells. Using fat-specific MTP knockdown mice, we will define the effects of the knockdown on body weight, body fat composition, energy expenditure, food consumption, leptin, and insulin. Glucose metabolism will also be assessed using glucose tolerance tests as well as hyperinsulinemic euglycemic clamps. Specific Aim 2. To determine the molecular mechanism by which MTP facilitates the growth and maturation of lipid droplets. These studies will test the hypothesis that MTP facilitates lipid droplet expansion via structural and functional properties of the molecule. Selected sites in the putative lipid binding region of MTP will be mutated to determine if MTP functions as a "fusogenic protein" in lipid droplet maturation. MTP inhibitors will be used to determine if lipid transfer activity is necessary for lipid droplet expansion. Specific Aim 3. To examine the mechanism by which MTP associates with lipid droplets in 3T3- L1 cells. These studies will test the hypothesis that association of MTP with triglyceride in specific regions in the ER membrane initiates the movement of MTP from the lumen of the ER to the lipid droplet surface. Confocal and electron microscopy as well as biochemical approaches will be used to examine subcellular locations of MTP in differentiating 3T3-L1 cells and its association with lipid droplets in comparison with selected members of the PAT family of lipid droplet proteins. PUBLIC HEALTH RELEVANCE: Obesity presents a major health problem in the United States, even among American Veterans. A study of Veterans receiving care at VA medical facilities during 2000, revealed that 68.4% of the women were overweight (BMI 25) with 37.4% classified as obese (BMI 30). Seventy-three percent of the men were overweight with 32.9% classified as obese. This epidemic poses a major health problem as obesity is associated with a number of complications include type 2 diabetes, insulin resistance, dyslipidemia, hypertension, and cardiovascular disease. Unfortunately, little is known about the pathophysiological basis of obesity, and the mechanisms that underlie the excessive accumulation of fat. Indeed, little is known about the basic steps in lipid droplet formation and maturation within the fat cell and the mechanisms that regulate fat deposition. The proposed studies will provide new insight into how fat is stored and could prove important in understanding the factors involved in obesity and its many complications, including cardiovascular disease.
描述(由申请人提供): 我们的实验室最近发现微粒体甘油三酯转移蛋白(MTP)在小鼠、大鼠和人类的脂肪细胞中表达,这是一种在肝细胞和肠细胞内组装富含甘油三酯的脂蛋白所必需的蛋白质。此外,MTP在3T3-L1细胞中也有表达,当这些细胞被诱导分化为脂肪细胞时,MTP的表达增加了~5倍。MTP以点状形式存在于脂滴表面,在相邻脂滴的接触点上尤为突出。当MTP表达被沉默并诱导细胞分化时,只形成非常小的(?lt;1.5米)脂滴。此外,当MTP被导入CHO细胞并刺激脂滴形成时,与没有MTP的细胞相比,形成了更大的液滴。最后,使用Cre-Lox方法下调小鼠脂肪组织中MTP的表达,可以减少肥胖,并使小鼠比同年龄对照组的小鼠更瘦。我们的工作假设是:MTP是脂肪细胞内脂滴成熟和扩张的关键成分。这一工作假说将被检验如下:具体目标1:确定脂滴成熟过程中对MTP的需求。这些研究将检验以下假设:MTP促进正常脂滴的扩张和生长,体内脂肪细胞中MTP的缺失会导致更瘦的小鼠体内脂肪减少,葡萄糖代谢改善。利用从脂肪特异性MTP基因敲除小鼠分离的原代前脂肪细胞和MTP表达被siRNA沉默的3T3-L1细胞,我们将评估MTP缺乏对分化、脂滴形成和成熟、从头脂肪生成和甘油代谢的影响。我们还将探讨MTP表达增强对原代前脂肪细胞和3T3细胞脂滴形成和成熟的影响。利用脂肪特异性MTP基因敲除小鼠,我们将确定该基因敲除对体重、身体脂肪组成、能量消耗、食物消耗、瘦素和胰岛素的影响。还将使用葡萄糖耐量试验和高胰岛素正血糖钳夹来评估葡萄糖代谢。具体目的2.确定MTP促进脂滴生长成熟的分子机制。这些研究将检验MTP通过分子的结构和功能特性促进脂滴扩张的假设。MTP假定的脂质结合区中的选定位点将被突变,以确定MTP是否在脂滴成熟过程中作为“融合蛋白”发挥作用。MTP抑制剂将用于确定脂质转移活性是否对脂滴扩张是必要的。具体目的3.研究MTP与3T3-L1细胞脂滴结合的机制。这些研究将检验这样的假设,即MTP与内质网膜特定区域的甘油三酯的结合启动了MTP从内质网管腔到脂滴表面的运动。将使用共聚焦显微镜和电子显微镜以及生化方法来研究MTP在分化3T3-L1细胞过程中的亚细胞位置及其与脂滴的关系,并与选定的PAT脂滴蛋白家族成员进行比较。 公共卫生相关性: 肥胖是美国的一个主要健康问题,甚至在美国退伍军人中也是如此。2000年在退伍军人医疗机构接受护理的一项研究显示,68.4%的女性超重(BMI 25),37.4%的女性肥胖(BMI 30)。73%的男性超重,其中32.9%被归类为肥胖。这一流行病构成了一个重大的健康问题,因为肥胖与一些并发症有关,包括2型糖尿病、胰岛素抵抗、血脂异常、高血压和心血管疾病。不幸的是,人们对肥胖的病理生理学基础以及脂肪过度积累的机制知之甚少。事实上,人们对脂肪细胞内脂滴形成和成熟的基本步骤以及调节脂肪沉积的机制知之甚少。拟议中的研究将为脂肪是如何储存的提供新的见解,并可能被证明对理解肥胖及其许多并发症(包括心血管疾病)所涉及的因素很重要。

项目成果

期刊论文数量(0)
专著数量(0)
科研奖励数量(0)
会议论文数量(0)
专利数量(0)

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Larry L. Swift其他文献

Morphologic abnormalities of erythrocytes from patients with homozygous familial hypercholesterolemia.
纯合子家族性高胆固醇血症患者红细胞形态异常。
  • DOI:
    10.1016/0005-2760(82)90104-7
  • 发表时间:
    1982
  • 期刊:
  • 影响因子:
    0
  • 作者:
    James B. Atkinson;Peter W. Stacpoole;Larry L. Swift
  • 通讯作者:
    Larry L. Swift
Plasma and Urine Riboflavin During Riboflavin-Free Nutrition in Very-Low-Birth-Weight Infants
极低出生体重婴儿无核黄素营养期间的血浆和尿液核黄素
Role of the Golgi apparatus in the phosphorylation of apolipoprotein B.
高尔基体在载脂蛋白 B 磷酸化中的作用。
Electron paramagnetic resonance and saturation transfer electron paramagnetic resonance studies on erythrocytes from goats with and without heritable myotonia
  • DOI:
    10.1007/bf01869122
  • 发表时间:
    1980-06-01
  • 期刊:
  • 影响因子:
    2.900
  • 作者:
    Larry L. Swift;James B. Atkinson;Ray C. Perkins;Larry R. Dalton;Virgil S. LeQuire
  • 通讯作者:
    Virgil S. LeQuire

Larry L. Swift的其他文献

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{{ truncateString('Larry L. Swift', 18)}}的其他基金

The Role of MTP in Lipid Droplet Formation in Adipocytes
MTP 在脂肪细胞脂滴形成中的作用
  • 批准号:
    8696774
  • 财政年份:
    2011
  • 资助金额:
    --
  • 项目类别:
The Role of MTP in Lipid Droplet Formation in Adipocytes
MTP 在脂肪细胞脂滴形成中的作用
  • 批准号:
    8141848
  • 财政年份:
    2011
  • 资助金额:
    --
  • 项目类别:
The Role of MTP in Lipid Droplet Formation in Adipocytes
MTP 在脂肪细胞脂滴形成中的作用
  • 批准号:
    8397561
  • 财政年份:
    2011
  • 资助金额:
    --
  • 项目类别:
Summer Research Training Program in Heart, Lung and Vascular Biology
心脏、肺和血管生物学夏季研究培训项目
  • 批准号:
    8017406
  • 财政年份:
    2008
  • 资助金额:
    --
  • 项目类别:
Summer Research Training Program in Heart, Lung and Vascular Biology
心脏、肺和血管生物学夏季研究培训项目
  • 批准号:
    7571695
  • 财政年份:
    2008
  • 资助金额:
    --
  • 项目类别:
Summer Research Training Program in Heart, Lung and Vascular Biology
心脏、肺和血管生物学夏季研究培训项目
  • 批准号:
    7765507
  • 财政年份:
    2008
  • 资助金额:
    --
  • 项目类别:
Summer Research Training Program in Heart, Lung and Vascular Biology
心脏、肺和血管生物学夏季研究培训项目
  • 批准号:
    7347771
  • 财政年份:
    2008
  • 资助金额:
    --
  • 项目类别:
Summer Research Training Program in Heart, Lung and Vascular Biology
心脏、肺和血管生物学夏季研究培训项目
  • 批准号:
    8235023
  • 财政年份:
    2008
  • 资助金额:
    --
  • 项目类别:
CORE--ANALYTICAL FACILITY /LIPIDS
核心--分析设施/脂质
  • 批准号:
    6564196
  • 财政年份:
    2002
  • 资助金额:
    --
  • 项目类别:
APOE RECYCLING: Cell Biology and Physiologic Relevance
APOE 回收:细胞生物学和生理相关性
  • 批准号:
    6538078
  • 财政年份:
    2001
  • 资助金额:
    --
  • 项目类别:

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The regulation of the GLUT4 gene expression during the differentiation of 3T3-L1 cells by the transcriptional represser
转录抑制因子对3T3-L1细胞分化过程中GLUT4基因表达的调控
  • 批准号:
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Study on the Pathogenesis of Graves' Ophthalmopathy using 3T3-L1 Cells Which Express Thyrotropin Receptor
表达促甲状腺素受体的3T3-L1细胞研究格雷夫斯眼病发病机制
  • 批准号:
    08671143
  • 财政年份:
    1996
  • 资助金额:
    --
  • 项目类别:
    Grant-in-Aid for Scientific Research (C)
CAVEOLAE FUNCTION IN 3T3-L1 CELLS
3T3-L1 细胞中的小窝功能
  • 批准号:
    2170149
  • 财政年份:
    1995
  • 资助金额:
    --
  • 项目类别:
CAVEOLAE FUNCTION IN 3T3-L1 CELLS
3T3-L1 细胞中的小窝功能
  • 批准号:
    2170148
  • 财政年份:
    1994
  • 资助金额:
    --
  • 项目类别:
STUDIES OF CAVEOLAE FUNCTION IN 3T3-L1 CELLS
3T3-L1 细胞中小窝功能的研究
  • 批准号:
    2170147
  • 财政年份:
    1993
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    --
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PILOT STUDY--REGULATION OF CAMP DEPENDENT PROTEIN KINASE IN CULTURED 3T3-L1 CELLS
中试研究--培养的 3T3-L1 细胞中营依赖性蛋白激酶的调节
  • 批准号:
    4689413
  • 财政年份:
  • 资助金额:
    --
  • 项目类别:
PILOT STUDY--HORMONE ACTION AND 3T3-L1 CELLS
试点研究——激素作用和 3T3-L1 细胞
  • 批准号:
    3875633
  • 财政年份:
  • 资助金额:
    --
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PILOT STUDY--REGULATION OF CAMP DEPENDENT PROTEIN KINASE IN CULTURED 3T3-L1 CELLS
中试研究--培养的 3T3-L1 细胞中营依赖性蛋白激酶的调节
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    3964276
  • 财政年份:
  • 资助金额:
    --
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PILOT STUDY--HORMONE ACTION AND 3T3-L1 CELLS
试点研究——激素作用和 3T3-L1 细胞
  • 批准号:
    3839649
  • 财政年份:
  • 资助金额:
    --
  • 项目类别:
PILOT STUDY--HORMONE ACTION AND 3T3-L1 CELLS
试点研究——激素作用和 3T3-L1 细胞
  • 批准号:
    3917493
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