Thioredoxin Interacting Protein (TXNIP) expression is critical in the development of early diabetic retinopathy

描述（由申请人提供）：线粒体（MT）失调和由此产生的能量失衡与各种慢性疾病有关，包括神经变性、缺血/再灌注和糖尿病并发症，如糖尿病视网膜病变（DR）。最近，我们发表了促氧化硫氧还蛋白相互作用蛋白（TXNIP）在包括Muller细胞（MC）在内的培养视网膜细胞的DR和高血糖状态下显著上调，并介导细胞氧化应激和炎症。TXNIP最近在一些研究中被认为是糖尿病及其并发症发病机制中的关键蛋白，包括DR. TXNIP与氧化还原抗氧化蛋白硫氧还蛋白（Trx）结合，抑制其活性氧（ROS）清除和硫醇还原能力；因此，导致细胞氧化/亚硝化（ROS/RNS）应激和异常的蛋白质s-亚硝基化。此外，神经胶质瘤对视网膜健康很重要，激活的神经胶质瘤诱导细胞因子和生长因子的异常基因表达，以维持视网膜的稳态。然而，长期的MC激活在dr中是有害的，因此，我们的总体假设是TXNIP在dr的发展中对MT功能障碍和MC激活至关重要。我们建议测试两个具体目标：目的1。TXNIP诱导早期DR MT功能障碍并引起核应激反应；还有目标。为了实现这一目标，我们将使用链脲佐菌素（STZ）诱导的大鼠和小鼠1型糖尿病模型，并结合TXNIP在视网膜中的表达水平。使用视网膜MC的体外研究也将进行，以解剖TXNIP如何诱导MT功能障碍和线粒体自噬的分子机制，从而特异性地去除受损的MT。我们的提议是创新的，因为我们解决了DR中尚未探索的重要研究领域，包括：(i) MT逆行应激信号以维持DR中的MT稳态；（ii）视网膜巨噬细胞分裂和有丝自噬的分子机制，对维持视网膜巨噬细胞稳态至关重要；（iii）了解TXNIP在视网膜巨噬细胞活化（胶质细胞形成）和视网膜神经元损伤/死亡中的作用；（iv）通过sirna靶向TXNIP启动子和染色质关闭（RNAi eTGS）在视网膜中敲除TXNIP的新策略的开发。因此，我们提出的创新研究将填补目前在理解DR发生和进展方面存在的知识空白。此外，结果将使我们能够确定潜在的目标

DESCRIPTION (provided by applicant): Mitochondrial (MT) dysregulation and resultant energy imbalance is associated with various chronic diseases including neuro-degeneration, ischemia/reperfusion, and diabetic complications such as diabetic retinopathy (DR). Recently, we published that pro-oxidant thioredoxin interacting protein (TXNIP) is significantly up-regulated in DR and under hyperglycemia in retinal cells in culture including Muller cells (MC) and mediates cellular oxidative stress and inflammation. TXNIP has recently been implicated by several studies as a critical protein in the pathogenesis of diabetes and its complications including DR. TXNIP binds to thioredoxin (Trx), a redox anti-oxidant protein, inhibiting its reactive oxygen species (ROS) scavenging and thiol reducing capacity; therefore, results in cellular oxidative/nitrosative (ROS/RNS) stress and aberrant protein s-nitrosylation. Furthermore, MC are important for retinal health and activated MC (gliosis) induces aberrant gene expression for cytokines and growth factors to maintain retinal homeostasis. However, prolonged MC activation is injurious in DR. Therefore, our overall hypothesis is that TXNIP is critical for MT dysfunction and MC activation in the development of DR. We propose to test two specific aims: aim 1. that TXNIP induces MT dysfunction and evokes nuclear stress responses in early DR; and aim 2. that TXNIP regulates MT fission and mitophagy in early DR. To address the objectives, we will use streptozotocin (STZ)-induced type 1 diabetic models of rat and mouse in conjunction with manipulation of TXNIP expression levels in the retina. In vitro studies using retinal MC will also be performed to dissect the molecular mechanisms as to how TXNIP induces MT dysfunction and mitophagy, which specifically removes damaged MT. Our proposal is innovative because we address still unexplored important areas of research in DR. These include: (i) MT retrograde stress signaling to maintain MT homeostasis in DR; (ii) molecular mechanism(s) of MT fission and mitophagy, critical for preservation of MT homeostasis in DR: (iii) understanding the role played by TXNIP in retinal MC activation (gliosis) and retinal neuronal injury/death in DR; and (iv) development of a novel strategy for TXNIP knock down in the retina by siRNA-targeted to TXNIP promoter and chromatin closing (RNAi eTGS). Hence, our proposed innovative studies will fill the knowledge gap that currently exists in understanding DR initiation and progression. Furthermore, the results will allow us to identify potential targets for developing new gene/drug therapies and ameliorate the ocular complications of diabetes.