Targeting the Etiology of Diabetic Retinopathy

项目摘要 糖尿病视网膜病变（DR）在临床上被定义为视网膜微血管系统的疾病，并且大多数研究 迄今为止，对其发病机理的研究主要集中在血管系统本身。多焦视网膜电图的研究进展 表明神经视网膜缺陷先于甚至预测DR的发展。因此， 研究导致视网膜早期丧失对代谢的适应的分子事件， 糖尿病的环境! mRNA的翻译是基因表达的主要调控步骤， 用于控制血管内皮生长因子（VEGF）的表达，以及其它关键的生长因子， 因子和细胞因子对代谢应激的反应。我们的中心假设是糖尿病引起的 在Müller神经胶质细胞内翻译mRNA的选择导致视网膜稳态的丧失， Müller细胞是视网膜的主要神经胶质细胞， 它们在维持血管系统和神经系统的稳态和营养因子的产生中起作用 视网膜层。在糖尿病患者中，胶质细胞活化发生在DR的临床表现之前， 作为适应性反应来减轻组织损伤。然而，Müller胶质细胞的长期变化 蛋白质表达成为视网膜并发症发展的原因。具体来说，缪勒胶质细胞是 糖尿病视网膜VEGF表达增加的主要来源，作为条件性Muller细胞特异性 VEGF的破坏防止生长因子表达升高并减少视网膜血管病变。我们 实验室已经表明，糖尿病诱导的翻译阻遏物4E-BP1的激活促进视网膜色素变性。 1型糖尿病模型中VEGF表达与视觉功能障碍的发生客观 这是为了解决我们对早期产生的分子事件的理解中的一个基本空白， Müller细胞特异性蛋白表达的变化。使用新开发的RiboTag小鼠模型，其中 表位标记的核糖体亚基的表达是针对Müller胶质细胞的，拟议的研究将提供 对完整视网膜内Müller神经胶质细胞中的免疫活性mRNA进行了前所未有的评估。的 提出的研究旨在表征两种翻译中选择特定mRNA的缺陷， 糖尿病实验模型：链脲佐菌素给药和高脂肪/高碳水化合物饮食。此外 为了确定导致神经胶质功能障碍的特定mRNA的调节机制， 研究还将评估两种实验模型中视网膜缺陷和视觉缺陷的发展情况。 在应激反应蛋白REDD 1或蛋白O- GlcNAc化（即两种介导mRNA翻译特异性变化的新机制）。的理由 一旦视网膜Müller细胞翻译控制机制的分子缺陷被发现， 翻译起始因子的功能/组装可以被操纵，从而产生新的 本发明涉及解决多种生长因子和细胞因子（包括VEGF）的表达失调的治疗剂。 !

Project Summary Diabetic retinopathy (DR) is clinically defined as a disease of the retinal microvasculature, and most research on its pathogenesis to date has focused on the vasculature itself. Recent advances in multifocal ERG demonstrate that neuro-retinal defects precede and even predict the development of DR. Thus, it is important to investigate the molecular events that contribute to early loss of retinal adaptation to the metabolic environment in diabetes.!Translation of mRNA is a major regulatory step in gene expression that is important for controlling the expression of vascular endothelial growth factor (VEGF), as well as other critical growth factors and cytokines in response to metabolic stress. Our central hypothesis is that a diabetes-induced shift in the selection of mRNAs for translation within Müller glia results in loss of retinal homeostasis and the eventual development of DR. Müller cells, the principal glial cell of the retina, are well recognized for the role they play in the production of homeostatic and trophic factors that support both the vasculature and neuronal layers of the retina. In diabetic patients, glial activation occurs prior to clinical manifestation of DR and likely serves as an adaptive response to mitigate tissue damage. However, prolonged changes in Müller glial protein expression become causative in the development of retinal complications. Specifically, Müller glia are the principal source of increased retinal VEGF expression in diabetes, as conditional Muller cell specific disruption of VEGF prevents elevated growth factor expression and reduces retinal vascular pathology. Our laboratory has shown that diabetes-induced activation of the translational repressor 4E-BP1 promotes retinal VEGF expression and the development of visual dysfunction in a model of type 1 diabetes. The objective here is to address a fundamental gap in our understanding of the molecular events that produce early changes in Müller cell specific protein expression. Using a newly developed RiboTag mouse model, wherein expression of an epitope-tagged ribosomal subunit is directed to Müller glia, the proposed studies will provide an unprecedented assessment of translationally active mRNAs in Müller glia within the intact retina. The proposed studies are designed to characterize defects in the selection of specific mRNAs for translation in two experimental models of diabetes: streptozotocin administration and high fat/high carbohydrate diet. In addition to identifying regulatory mechanisms for specific mRNAs that contribute to glial dysfunction, the proposed studies will also assess the development of retinal defects and visual deficits in the two experimental models following Müller-specific genetic manipulation of the stress response protein REDD1 or protein O- GlcNAcylation (i.e. two novel mechanisms for mediating specific changes in mRNA translation). The rationale is that once the molecular defects in translational control mechanisms in retinal Müller cells are known, the function/assembly of translation initiation factors can be manipulated pharmacologically, resulting in new therapeutics that address dysregulated expression of multiple growth factors and cytokines including VEGF. !