Targeting the Etiology of Diabetic Retinopathy

项目摘要 糖尿病视网膜病变(DR)在临床上被定义为一种视网膜微血管疾病，大多数研究 到目前为止，其发病机制主要集中在血管系统本身。多焦视网膜电图的研究进展 证明神经-视网膜缺陷先于甚至预测DR的发展，因此，它是重要的 研究导致视网膜对代谢的早期适应性丧失的分子事件 糖尿病中的环境。！mRNA的翻译是基因表达的一个重要调节步骤，这一点很重要 用于控制血管内皮生长因子(VEGF)的表达以及其他关键生长 代谢应激反应中的因子和细胞因子。我们的中心假设是糖尿病引起的转变 在Müller胶质细胞中选择要翻译的mRNAs会导致视网膜动态平衡的丧失和 作为视网膜的主要神经胶质细胞，Müler博士细胞的最终发展被公认为是这一角色 它们在体内平衡和营养因子的产生中发挥作用，这些因子既支持血管系统又支持神经元。 视网膜的几层。在糖尿病患者中，神经胶质细胞的激活发生在糖尿病视网膜病变的临床表现之前，可能 作为一种适应性反应，以减轻组织损伤。然而，穆勒神经胶质细胞的长期变化 蛋白表达在视网膜并发症的发生中起重要作用。具体地说，Müler glia是 糖尿病患者视网膜血管内皮生长因子表达增加的主要来源，作为条件米勒细胞特异性 阻断血管内皮生长因子可防止生长因子表达升高，并减少视网膜血管病变。我们的 实验室表明，糖尿病引起的翻译抑制因子4E-BP1的激活促进了视网膜 血管内皮生长因子的表达与1型糖尿病模型视觉功能障碍的发展。目标是 这里是为了解决我们对早期产生的分子事件的理解中的一个根本差距 Müler细胞特异性蛋白表达的变化。使用一种新开发的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 一项史无前例的对完整视网膜内Müler胶质中翻译活性mRNAs的评估。这个 拟议的研究旨在描述在选择用于翻译的特定mRNAs时存在的缺陷 糖尿病动物模型：链脲佐菌素灌胃和高脂高糖饮食。此外 为了确定导致神经胶质功能障碍的特定mRNAs的调控机制，建议的 研究还将评估两个实验模型中视网膜缺陷和视力缺陷的发展情况。 在米勒对应激反应蛋白Redd1或蛋白O进行特定的遗传操作后- GlcN酰化(即两种新的机制，用于调节mRNA翻译中的特定变化)。其基本原理是 一旦知道视网膜Müler细胞翻译控制机制中的分子缺陷， 翻译起始因子的功能/组装可以通过药理学进行操纵，从而产生新的 解决多种生长因子和包括血管内皮生长因子在内的细胞因子表达失调的治疗方法。 好了！

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. !