Redox-sensitive activation of REDD1 in diabetic retinopathy

项目摘要 糖尿病视网膜病变（DR）是视力丧失的主要原因，但关于分子机制仍有许多未知之处。 导致这种普遍并发症的事件。糖尿病促进应激反应蛋白的表达 视网膜中的发育和DNA损伤1（REDD 1）调节，这与视觉缺陷有关 在临床前模型和糖尿病患者中。REDD 1蛋白在啮齿动物视网膜中的表达增加 在1型和2型糖尿病模型中，REDD 1缺失可防止糖尿病诱导的视网膜病变的发展。 病理学和视觉功能缺陷。玻璃体内给予靶向REDD 1 mRNA的siRNA， 也显示出改善糖尿病黄斑水肿患者的视觉功能的前景。综合这些 研究结果提供了强有力的支持，即REDD 1在视力功能缺陷中起着重要作用， 由糖尿病引起的。这里的目标是解决两个关键的未解决的基础研究问题， REDD 1在DR中的作用。拟议的研究将调查为什么视网膜REDD 1蛋白表达是 糖尿病增加。我们还将探索REDD 1下游的分子事件，以确定它是如何影响REDD 1的。 会导致视力受损基本原理是，对导致 REDD 1蛋白质含量增加，以及那些对视力有害的蛋白质， 确定用于改进治疗策略的分子靶点，在临床前早期提供干预 核心假设是糖尿病抑制REDD 1蛋白 在视网膜中的降解促进氧化应激、炎症和随后的视网膜病理学。目标1将 研究REDD 1蛋白中可能被糖尿病激活的分子开关， REDD 1退化。拟议的研究将使用体内SNAP标记来定义生物化学事件， 调节糖尿病小鼠视网膜中的REDD 1降解。目标2将建立在我们实验室最近的证据基础上 支持REDD 1作为核因子红细胞-2相关因子2（Nrf 2）的显性调控者 抗氧化反应我们预测，糖尿病通过促进视网膜中的抗氧化反应来阻止视网膜中适当的抗氧化反应。 通过REDD 1依赖性激活糖原合成酶激酶3（GSK 3）的Nrf 2核排斥。目标3将 研究REDD 1在视网膜炎症中的作用，因为最近显示REDD 1促进非典型激活 核因子-κ B（NF-κB）通过与κB抑制剂（IκB）直接相互作用和隔离而发挥作用。公 建立了氧化应激和炎症是发展和进展的关键因素， 导致视力受损的并发症。拟议的研究旨在识别和表征 导致视网膜氧化应激和炎症发展的特定分子事件 1型和2型糖尿病，通过解决与尖端治疗目标相关的关键知识差距。为此， 我们将探索一个全新的概念，即REDD 1的非酶促翻译后修饰 蛋白是DR中Nrf 2和NF-κB异常激活的共同机制。

Project Summary Diabetic retinopathy (DR) is a leading cause of vision loss, yet much remains unknown regarding the molecular events that cause this pervasive complication. Diabetes promotes expression of the stress response protein regulated in development and DNA damage 1 (REDD1) in the retina, which has been implicated in visual deficits in both preclinical models and diabetic patients. REDD1 protein expression is increased in the retina of rodent models of type 1 and type 2 diabetes, and REDD1 deletion prevents the development of diabetes-induced retinal pathology and functional deficits in vision. Intravitreal administration of a siRNA targeting the REDD1 mRNA has also demonstrated promise for improving visual function in patients with diabetic macular edema. Together these findings provide strong support that REDD1 plays an important role in the functional deficits in vision that are caused by diabetes. The objective here is to address two critical unresolved basic research questions related to the role of REDD1 in DR. The proposed studies will investigate why retinal REDD1 protein expression is increased by diabetes. We will also explore the molecular events downstream of REDD1 to determine how it contributes to visual impairment. The rationale is that an understanding of the molecular events that lead to increased REDD1 protein content, as well as those that are responsible for its deleterious effects on vision, may identify molecular targets for improved therapeutic strategies that provide interventions early in the preclinical and non-proliferative stages of DR. The central hypothesis is that diabetes suppresses REDD1 protein degradation in the retina to promote oxidative stress, inflammation, and subsequent retinal pathology. Aim 1 will investigate a molecular switch in the REDD1 protein that is potentially activated by diabetes, leading to reduced REDD1 degradation. The proposed studies will use in vivo SNAP-tagging to define the biochemical events that regulate REDD1 degradation in the retina of diabetic mice. Aim 2 will build on recent evidence from our laboratory supporting that REDD1 acts as a dominant governor of the nuclear factor erythroid-2-related factor 2 (Nrf2) antioxidant response. We predict that diabetes prevents a proper antioxidant response in the retina by promoting Nrf2 nuclear exclusion via REDD1-dependent activation of glycogen synthase kinase 3 (GSK3). Aim 3 will investigate a role for REDD1 in retinal inflammation, as REDD1 was recently shown to promote atypical activation of nuclear factor kappa B (NF-κB) by directly interacting with and sequestering inhibitor of κB (IκB). It is well established that oxidative stress and inflammation are crucial factors in the development and progression of the complications that cause visual impairment. The proposed studies are designed to identify and characterize specific molecular events that contribute to the development of retinal oxidative stress and inflammation in type 1 and type 2 diabetes by addressing key knowledge gaps related to a cutting-edge therapeutic target. To do so, we will explore the entirely novel concept that non-enzymatic post-translational modification of the REDD1 protein is a shared mechanism for improper activation of Nrf2 and NF-κB in DR.