Regulation of endogenous antioxidant systems in diabetic retinopathy

糖尿病视网膜病变内源性抗氧化系统的调节

• 批准号: 9186548
• 负责人: MANUELA BARTOLI
• 金额: $ 37.5万
• 依托单位: AUGUSTA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-12-01 至 2018-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9186548
• 关键词: Ablation; Acetylation; Antioxidants; Biological; Biological Availability; Blindness; Chronic; Complex; Data; Deacetylation; Development; Diabetes Mellitus; Diabetic Retinopathy; Down-Regulation; Endothelial Cells; Event; Functional disorder; Genes; Glucose; Goals; HDAC6 gene; Homeostasis; Human; Hyperglycemia; Impairment; In Vitro; Inflammation; Inflammatory; Inflammatory Response; Mediating; Modeling; Modification; Molecular; Nitrates; Oxidation-Reduction; Oxidative Stress; Oxidative Stress Induction; Pathogenesis; Pathogenicity; Patients; Pericytes; Phosphorylation; Play; Post-Translational Protein Processing; Process; Rattus; Regulation; Retina; Retinal; Role; Serine; Small Interfering RNA; Streptozocin; System; TXN gene; TXNIP gene; Testing; Time; antioxidant therapy; design; diabetic; diabetic rat; experimental study; gain of function; in vivo; mutant; nitration; overexpression; prevent; protein function; protein kinase C-delta; public health relevance; thioredoxin reductase 1

DESCRIPTION (provided by applicant): We aim at investigating the molecular mechanisms of hyperglycemia-induced dysfunction of the endogenous antioxidant system of the thioredoxins (TrxS) in the diabetic retina. Our overall goal is to identify ways to rescue the activity of this critical regulator of cellular redox homeostasis in diabetes mellitus, thereby, preventing hyperglycemia-induced oxidative stress (OxS) and chronic inflammatory processes. To date, hyperglycemia-induced loss of TrxS function has been attributed only to increased expression of the thioredoxin interacting protein (TXNIP). However, in streptozotocin-induced diabetic rats (STZ-rats) and human diabetic retinas, we have discovered that hyperglycemia promotes serine phosphorylation of TXNIP (TXNIP- SerP), nitration/inactivation of the thioredoxin reductase 1(TrxR1-NY) and deacetylation of thioredoxin 1(Trx1). These modifications are associated with decreased bioavailability of the reduced (active) form of Trx1, the operating unit of the system, and with TXNIP gain of function. We have also determined that TXNIP and Trx1 post-translational modifications, involve the activity of protein kinase C delta (PKCδ) and histone deacetylase 6 (HDAC6), respectively, implicating for the first time HDAC6 in the pathogenesis of DR and disclosing a new function of PKCδ in the diabetic retina. We have designed experiments aimed at validating our hypothesis that: in the diabetic retina, impaired function of TrxS results from TXNIP serine phosphorylation, TrxR1 nitration/ inactivation and Trx1 deacetylation. These modifications of the TrxS constituents will lead to impaired antioxidant ability, induction of inflammatory processes and progression to DR. We have designed experiments to be conducted in vitro on isolated retinal pericytes (RPC) and endothelial cells (REC) exposed to elevated glucose levels (HG) and osmotic controls. In vivo experiments will be conducted by using streptozotocin-induced diabetic rats (STZ-rats, a model of Type1 diabetes). Aim1. Test the hypothesis that PKCδ-dependent TXNIP-SerP contributes to retinal OxS, inflammation and progression to DR. Aim2. Test the hypothesis that TrxR1-NY contributes to retinal OxS and progression to DR. Aim3. Test the hypothesis that HDAC6-mediated de-acetylation of Trx1 contributes to retinal OxS, inflammation and progression to DR.

描述(申请人提供)：我们的目标是研究高血糖导致糖尿病视网膜内源性硫氧还蛋白(Trxs)抗氧化系统功能障碍的分子机制。我们的总体目标是找出在糖尿病中挽救这一细胞氧化还原稳态的关键调节因子活性的方法，从而防止高血糖诱导的氧化应激(OXS)和慢性炎症过程。到目前为止，高血糖诱导的Trxs功能丧失仅归因于硫氧还蛋白相互作用蛋白(TXNIP)的表达增加。然而，在链脲佐菌素诱导的糖尿病大鼠(STZ大鼠)和人类糖尿病视网膜中，我们发现高血糖促进TXNIP的丝氨酸磷酸化(TXNIP-SERP)、硫氧还蛋白还原酶1(TrxR1-NY)的硝化/失活和硫氧还蛋白1(Trx1)的去乙酰化。这些修改与减少的(主动)形式的Trx1(系统的操作单元)的生物利用度降低以及功能的TXNIP增益有关。我们还确定了TXNIP和Trx1的翻译后修饰，分别涉及蛋白激酶C增量(PKCδ)和组蛋白脱乙酰基酶6(HDAC6)的活性，首次表明HDAC6参与了DR的发病机制，并揭示了PKCδ在糖尿病视网膜中的新功能。我们设计的实验旨在验证我们的假设：在糖尿病视网膜中，Trxs功能受损的原因是TXNIP丝氨酸磷酸化、TrxR1硝化/失活和Trx1去乙酰化。Trxs成分的这些修饰将导致抗氧化能力受损、诱导炎症过程和进展为DR。我们设计了在体外对暴露在高血糖(HG)和渗透压控制下的分离的视网膜周细胞(RPC)和内皮细胞(REC)进行的实验。体内实验将使用链脲佐菌素诱导的糖尿病大鼠(STZ-大鼠，一种1型糖尿病模型)。目的：1.测试PKCδ依赖的血栓素NIP-SERP促进视网膜过氧化、炎症和进展到AIM2博士的假设。测试TrxR1-NY导致视网膜OXS和进展到Dr.Aim3的假设。验证HDAC6介导的Trx1去乙酰化有助于视网膜OXS、炎症和进展为DR的假设。