Glucose transport in the diabetic outer retina.

糖尿病外视网膜中的葡萄糖转运。

• 批准号: 9487896
• 负责人: Ivy S Samuels
• 金额: --
• 依托单位: LOUIS STOKES CLEVELAND VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-10-01 至 2019-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9487896
• 关键词: AIDS therapy; Abate; Adult; Affect; Background Diabetic Retinopathy; Binding; Blindness; Blood; Blood Glucose; Blood-Retinal Barrier; Cell Culture Techniques; Cells; Clinical; Clinical Trials; Defect; Development; Diabetes Mellitus; Diabetes prevention; Diabetic Retinopathy; Diabetic mouse; Diffusion; Disease; Electron Microscopy; Electroretinography; Event; Eye; Functional disorder; Generations; Genes; Glucose; Glucose Transporter; Goals; Hyperglycemia; Hyperglycemic Mice; Image; In Vitro; Insulin; Insulin Receptor; Insulin-Dependent Diabetes Mellitus; Laboratories; Leukostasis; Measures; Mediating; Membrane; Methods; Modeling; Molecular; Mus; Pathology; Patients; Phase; Photoreceptors; Play; Prevention; Preventive therapy; Reagent; Receptor Signaling; Regulation; Research; Resources; Retina; Retinal; Retinal Diseases; Risk Factors; Role; SLC2A1 gene; Serum; Severities; Signal Transduction; Structure of retinal pigment epithelium; Superoxides; Symptoms; Techniques; Testing; Therapeutic Intervention; Time; United States; Veterans; Vision; Work; aged; apical membrane; basolateral membrane; blood glucose regulation; blood lead; diabetes risk; diabetic; early detection biomarkers; experimental study; glucose analog; glucose monitor; glucose transport; glycemic control; in vivo; innovation; insulin signaling; microvascular pathology; mouse model; novel; novel therapeutics; prevent; public health relevance; success; targeted treatment; ubiquitin-protein ligase

 DESCRIPTION (provided by applicant): Hyperglycemia is the major risk factor for development of diabetic retinopathy. Tight control of serum glucose levels is currently viewed as the primary means to slow progression to retinopathy, but the mechanisms by which glucose enters the retina and how they become perturbed in diabetes remains unclear. Therefore, understanding the mechanism of how hyperglycemia affects the outer retina (RPE and photoreceptors) and identifying methods to ameliorate glucose-induced outer retina dysfunction and early biomarkers of diabetic retinopathy is important. Recently, it has been shown that systemic reduction of the facilitative diffusion glucose transporter, GLUT1 will reduce glucose levels in the retina; however, these studies do not provide a mechanism or means to control glucose entry specifically to the retina via the blood retinal barrier (BRB). The first objective of this proposal is to determine if reductions in GLUT1 within the RPE leads to reduced retinal glucose accumulation within the RPE/outer retina, prevention of RPE dysfunction and early biomarkers of diabetic retinopathy in mouse models of diabetes. The second objective is to investigate mechanisms of GLUT1 modulation by insulin and to determine if abrogation of insulin signal transduction in the RPE can mitigate abnormal RPE function in mouse models of diabetes by regulation of GLUT1 expression and localization. We hypothesize that (1) hyperglycemia-induced increases in the expression and redistribution of GLUT1 in the RPE mediates diabetes-associated reductions in RPE/outer retina function and early signs of retinopathy, (2) that insulin also modulates glucose transport by GLUT1 in the RPE and (3) that blockade of insulin signaling in the RPE will exacerbate retinal pathophysiology found in a mouse model of diabetes. To test these hypotheses, a mouse model of type 1 diabetes will be employed to investigate GLUT1 expression and distribution within the apical and basolateral membranes of the RPE and determine if this is concomitant with an accumulation of intracellular glucose. To determine if reductions in GLUT1 expression prevents outer retina dysfunction, a haploinsufficient Glut1+/- mouse and mice in which the Glut1 gene is specifically inactivated only within the RPE will be utilized. To additionally assess how insulin affects GLUT1-mediated glucose entry and accumulation in the retina, conditional inactivation the insulin receptor (IR) will be employed to abrogate downstream signaling from this receptor. In vitro analysis of cultured RPE cells will also be used to determine if insulin treatment alters glucose transport through regulation of GLUT1 by affecting its association with a binding partner, GIPC and/or the E3 ubiquitin ligase, Nedd4-2. These experiments will determine the role that GLUT1 plays in outer retina dysfunction as a result of hyperglycemia, elucidate how insulin is involved in GLUT1 modulation, and identify a mechanism which can be targeted for therapeutic intervention.

 描述（由申请人提供）： 高血糖是发展糖尿病性视网膜病的主要危险因素。目前，严格控制血清葡萄糖水平是减慢视网膜病变的主要手段，但是葡萄糖进入视网膜的机制以及它们在糖尿病中的扰动方式尚不清楚。因此，了解高血糖如何影响外视网膜（RPE和感光体）的机制，并确定改善葡萄糖诱导的视网膜外部功能障碍和糖尿病性视网膜病的早期生物标志物的方法。最近，已经表明，基本扩散葡萄糖转运蛋白的全身降低将降低视网膜中的葡萄糖水平。但是，这些研究并未提供通过血液残留屏障（BRB）专门控制葡萄糖进入葡萄糖的机制或手段。该提案的第一个目的是确定RPE内GLUT1的减少是否导致RPE/外视网膜内视网膜葡萄糖的积累减少，预防RPE功能障碍和糖尿病性视网膜疗法的早期生物标志物在糖尿病模型中的早期生物标志物。第二个目标是通过胰岛素调节GLUT1调节的机制，并确定RPE中胰岛素信号转导的促成是否可以通过调节GLUT1表达和定位来降低糖尿病小鼠模型中的异常RPE功能。我们假设（1）高血糖引起的增加。 In the expression and redistribution of GLUT1 in the RPE mediates diabetes-associated reductions in RPE/outer retina function and early signs of retinopathy, (2) that insulin also modulates glucose transport by GLUT1 in the RPE and (3) that blockade of insulin signaling in the RPE will exacerbate retinal pathophysiology found in a mouse model of diabetes.为了检验这些假设，将聘请1型糖尿病的小鼠模型来研究RPE的顶端和基底外侧机制内的GLUT1表达和分布，并确定这是否与细胞内葡萄糖的积累相关。为了确定GLUT1表达的降低是否阻止了视网膜外功能障碍，将使用GLUT1基因在RPE内专门灭活的单倍glut1 +/-小鼠和小鼠。另外，为了评估胰岛素如何影响GLUT1介导的葡萄糖进入和视网膜中的积累，有条件的失活胰岛素受体（IR）将被用来从该受体中消除下游信号传导。对培养的RPE细胞的体外分析也将用于确定胰岛素治疗是否通过与结合伴侣的缔合GIPC和/或E3泛素连接酶NEDD4-2的结合来通过调节GLUT1来改变葡萄糖的转运。这些实验将确定GLUT1由于高血糖而导致的视网膜外功能障碍的作用，阐明胰岛素如何参与GLUT1调节，并确定可以针对治疗干预的机制。