Redox-sensitive activation of REDD1 in diabetic retinopathy

项目摘要 糖尿病视网膜病变(DR)是导致视力丧失的主要原因，但关于其分子机制尚不清楚。 导致这种普遍的复杂性的事件。糖尿病促进应激反应蛋白的表达 视网膜发育和DNA损伤调控基因1(Redd1)，与视力障碍有关 在临床前模型和糖尿病患者中。啮齿动物视网膜中Redd1蛋白表达增加 1型和2型糖尿病模型和Redd1缺失可防止糖尿病视网膜的发展 视力的病理和功能缺陷。玻璃体内注射靶向Redd1mRNA的siRNA 也展示了改善糖尿病黄斑水肿患者的视觉功能的前景。把这些放在一起 研究结果有力地支持了Redd1在视力功能缺陷中扮演着重要角色 由糖尿病引起的。这里的目标是解决相关的两个关键的尚未解决的基础研究问题 对于Redd1在DR中的作用，拟议的研究将调查为什么视网膜Redd1蛋白表达 因糖尿病而增加。我们还将探索Redd1下游的分子事件，以确定它是如何 会导致视力障碍。其基本原理是对分子事件的理解导致 Redd1蛋白质含量的增加，以及那些对视力有害的影响，可能 确定改进治疗策略的分子靶点，以便在临床前早期提供干预 和DR的非增殖期中心假说是糖尿病抑制Redd1蛋白 视网膜的降解，促进氧化应激、炎症和随后的视网膜病理。目标1将 研究Redd1蛋白中的分子开关，它可能被糖尿病激活，导致减少 Redd1降级。拟议的研究将使用体内SNAP标记来定义 调节糖尿病小鼠视网膜中Redd1的降解。目标2将以我们实验室的最新证据为基础 支持Redd1作为核因子红系相关因子2(NRF2)的主要调控者 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的适当抗氧化反应。 NRF2通过依赖Redd1激活糖原合成酶激酶3(GSK3)进行核排斥。目标3将 研究Redd1在视网膜炎症中的作用，因为最近发现Redd1促进非典型激活 核因子-κB(NF-κB)通过与核转录因子B(IκB)直接相互作用和隔离抑制物(IκB)而被激活。这很好 证实氧化应激和炎症是糖尿病的发生和发展的关键因素 导致视力障碍的并发症。拟议的研究旨在确定和表征 导致视网膜氧化应激和炎症发生的特定分子事件 通过解决与尖端治疗目标相关的关键知识差距，1和2型糖尿病。要做到这一点， 我们将探索一个全新的概念，即Redd1的非酶翻译后修饰 蛋白质是DR中NRF2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.