Regulation of Fructose Transport by Thioredoxin-Interacting Protein

硫氧还蛋白相互作用蛋白对果糖转运的调节

• 批准号: 9171070
• 负责人: RICHARD T LEE
• 金额: $ 38.03万
• 依托单位: HARVARD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9171070
• 关键词: American; Americas; Amino Acids; Animals; Antioxidants; Arrestins; Binding; Binding Proteins; Cells; Civilization; Consumption; Data; Deposition; Diabetes Mellitus; Diet; Engineering; Enterocytes; Fatty Liver; Fatty acid glycerol esters; Fluorescence; Fructose; G-Protein-Coupled Receptors; GLUT2 gene; Gene Expression; Glucose; Glucose Intolerance; Glucose Transporter; Health; Hepatic; Homeostasis; Human; In Vitro; Intestinal Absorption; Intestines; Kinetics; Knock-in; Lead; Liver; Liver diseases; Mediating; Metabolic; Metabolic Diseases; Metabolism; Microscopy; Molecular; Mus; Mutation; Names; Obesity; Organ; Oxidation-Reduction; Pathway interactions; Photons; Play; Protein Family; Proteins; Regulation; Reporting; Role; SLC2A1 gene; Small Intestines; Specificity; Structure; TXN gene; TXNIP gene; Testing; Transgenic Mice; United States; Visual; Wild Type Mouse; apical membrane; base; basolateral membrane; beta-arrestin; glucose metabolism; glucose tolerance; glucose uptake; improved; in vivo; insight; liver injury; loss of function; member; non-alcoholic fatty liver; novel; overexpression; promoter; protein expression; protein function; recombinase; research study; theories; time use; uptake; villin

Fructose consumption has increased in modern America, and fructose consumption may play a role in metabolic diseases including obesity and diabetes. Fructose transport is regulated by a protein family of glucose transporters (GLUTs), and the fructose transporter GLUT5 is expressed in enterocytes from the small intestine. Thioredoxin-Interacting Protein (Txnip) is a member of a mammalian protein superfamily that contains arrestin-like domains. Here, we present new preliminary data showing that Txnip interacts with the fructose transporter GLUT5. We also show that overexpression of Txnip increases cellular fructose uptake in vitro, while deletion of Txnip inhibits fructose uptake. Our preliminary in vivo experiments further demonstrate that a high fructose diet causes non-alcoholic fatty liver disease in wild type mice, while mice deficient in Txnip have reduced intestinal fructose transport and hepatic fat deposition following a fructose diet. These data support a new overall theory that Txnip enhances fructose transport through specific molecular interactions with GLUT5. The experiments proposed here will likely reveal the molecular basis for a new pathway in fructose metabolism. Our Specific Aims are: Specific Aim 1 will test the hypothesis that a specific molecular interaction through an alpha arrestin-domain in Txnip regulates GLUT5 and GLUT2 functions. Here we will dissect the molecular specificity of this interaction by structure-function analysis. Specific Aim 2 will test the hypothesis that enterocyte Txnip regulates intestinal fructose transport and promotes hepatic steatosis in vivo. Targeted loss of function of Txnip will be used to test this hypothesis in vivo. We will generate intestine-specific Cre-mediated deletion of Txnip in mice, by crossing the Txnip flox/flox mouse that we engineered with a transgenic mouse bearing a Cre recombinase expressed under the control of the villin promoter. Specific Aim 3 will test the hypothesis that Txnip increases intestinal fructose transport through a redox-mediated mechanism in vivo. In this aim, we will test if GLUT5 regulation is controlled by Txnip through a thioredoxin-dependent redox-mediated mechanism, using a novel mouse with a “knock- in” mutation of Txnip that we have just generated. This mouse has a single amino acid change that eliminates binding of Txnip to thioredoxin, and thus renders Txnip function independent of thioredoxin redox state.

在现代美国，果糖的消费量增加了，果糖的消费可能起到了一定的作用 包括肥胖和糖尿病在内的代谢性疾病。果糖转运受一个蛋白质家族调节， 葡萄糖转运蛋白（GLUTs），果糖转运蛋白GLUT 5在肠上皮细胞中表达， 小肠硫氧还蛋白相互作用蛋白（Txnip）是哺乳动物蛋白质超家族的成员 含有抑制蛋白样结构域。在这里，我们提出了新的初步数据，表明Txnip与 果糖转运蛋白GLUT 5。我们还表明，Txnip的过度表达增加了细胞果糖 在体外，Txnip的缺失抑制果糖摄取，而Txnip的缺失抑制果糖摄取。我们的初步体内实验进一步 证明高果糖饮食会导致野生型小鼠的非酒精性脂肪肝， 缺乏Txnip的人在果糖摄入后肠果糖转运和肝脏脂肪沉积减少 饮食.这些数据支持了一个新的整体理论，即Txnip通过特异性途径增强果糖转运。 与GLUT 5的分子相互作用。这里提出的实验可能会揭示分子基础 寻找果糖代谢的新途径我们的具体目标是： 具体目标1将检验一个假设，即一个特定的分子相互作用，通过一个α Txnip中的抑制蛋白结构域调节GLUT 5和GLUT 2功能。在这里，我们将剖析分子 通过结构-功能分析确定这种相互作用的特异性。 具体目标2将检验肠上皮细胞Txnip调节肠果糖的假设 在体内转运并促进肝脂肪变性。Txnip的目标功能丧失将用于测试 这一假设在体内。我们将在小鼠中产生酪氨酸特异性Cre介导的Txnip缺失， 将我们设计的Txnip flox/flox小鼠与携带Cre重组酶的转基因小鼠杂交， 在绒毛蛋白启动子的控制下表达。 具体目标3将检验Txnip增加肠道果糖转运的假设 通过体内氧化还原介导的机制。为此，我们将测试GLUT 5调节是否受控 通过硫氧还蛋白依赖性氧化还原介导的机制，使用一种新的小鼠与“敲- 我们刚刚生成的”Txnip突变“。这只老鼠有一个单一的氨基酸变化， 消除了Txnip与硫氧还蛋白的结合，从而使Txnip的功能不依赖于硫氧还蛋白的氧化还原 状态