Intravitreal ECE-1 siRNA Treatment for Retinal Dysfunction during Early Diabetes

玻璃体内 ECE-1 siRNA 治疗早期糖尿病视网膜功能障碍

• 批准号: 8821045
• 负责人: TRAVIS W HEIN
• 金额: $ 21.98万
• 依托单位: TEXAS A&M UNIVERSITY HEALTH SCIENCE CTR
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8821045
• 关键词: Address; Advanced Development; American; Animal Model; Animals; Big Endothelin; Blindness; Blood Glucose; Blood Vessels; Blood flow; Cells; Clinical; Complications of Diabetes Mellitus; Cultured Cells; Data; Development; Diabetes Mellitus; Diabetic Retinopathy; Disease; Early treatment; Electroretinography; Endothelin-1; Endothelin-converting enzyme 1; Endothelium; Event; Eye; Eye diseases; Family suidae; Functional disorder; Goals; Human; Impairment; Insulin-Dependent Diabetes Mellitus; Ischemia; Mediating; Microcirculation; Modality; Modeling; Molecular; Molecular Target; Neural Retina; Neurons; Neurophysiology - biologic function; Nitric Oxide; Nutrient; Nutritional; Oxygen; Pathogenesis; Pathology; Physiological; Process; Production; Proteins; Regulation; Reporting; Resistance; Retina; Retinal; Retinal Diseases; Role; Site; Small Interfering RNA; Smooth Muscle; Staging; Streptozocin; System; Testing; Time; Treatment Protocols; United States; Vasoconstrictor Agents; Vasodilator Agents; Vasomotor; Vision; Visual impairment; animal model development; arteriole; constriction; diabetic; early onset; effective therapy; improved; in vivo; innovation; intravitreal injection; public health relevance; receptor; relating to nervous system; response; retinal damage; retinal ischemia; success; vasoconstriction

DESCRIPTION (provided by applicant): Retinopathy is a major complication of diabetes mellitus and a leading cause of blindness in the United States. Treatment modalities for restoring retinal function are relatively ineffective. Although alterations of both neural and vascular retina have been reported, the temporal relationship between neural retina damage and vasomotor dysfunction of resistance arterioles, the major site for blood flow regulation to the inner retina, remains unclear. This is important since reduced retinal blood flow occurs during early diabetes, which suggests that dysfunction of arterioles leading to ischemia may contribute to neural retina damage. However, mechanisms contributing to retinal vasomotor dysfunction in diabetes that are amenable to treatment prior to establishment of overt pathology remain unclear. Furthermore, development of an animal model of diabetes relevant to the human retinal microcirculation and its pathophysiology is lacking. To address these clinically important issues, we have developed a streptozocin-induced type 1 diabetes model in the pig, which we have shown resembles human in retinal vasomotor regulation/dysregulation. Our preliminary data show that within 2 wk of diabetes, endothelium-dependent nitric oxide (NO)-mediated dilation of retinal arterioles is impaired and constriction to big endothelin-1, the endothelin-1 (ET-1) precursor substrate for endothelin-converting enzyme- 1 (ECE-1), is enhanced without altering constriction to ET-1 per se. Although the smooth muscle response to ET-1 is unaltered, the ability to synthesize ET-1 is increased due to elevated ECE-1 expression. A potential harmful role for increased ET-1, besides its potent vasoconstrictor action, is its ability to inhibit NO production; however, whether ET-1 synthesis blockade can improve dilation during diabetes is unknown. Since retinal lactate level is increased within 2-wk diabetes and scotopic b-wave amplitude is reduced during 6-wk but not 2- wk diabetes, it appears vasomotor dysfunction promoting ischemia precedes inner neural retina damage. We recently detected ECE-1 in retinal arterioles but not neural retina, so ECE-1 may provide a specific vascular target for improving retinal arteriolar function, along with secondary amelioration of neural retina function, during early diabetes. Thus, the goal of this study is to understand the role of the ET-1 system in initiating retinal dysfunction by optimizing delivery of small interfering RNA (siRNA) via intravitreal injection to restore retinal arteriolar function. We will test the hypothesis that eary diabetes augments ECE-1 activity and ET-1 production leading to impairment of endothelium-dependent NO-mediated dilation of retinal arterioles prior to alteration of the neural retina function. To support the hypothesis and to test the feasibility of siRNA treatment, we will pursue the following specific aim: Determine whether molecular knockdown of ECE-1 in retinal arterioles improves diabetes-induced dysfunction of endothelium and neural retina. This innovative study will provide the first longitudinal assessment of both vascular and neural function in the retina from the same animal during diabetes, which will help in our understanding of retinal pathogenesis and development of new therapies for early treatment.

描述（由申请人提供）：视网膜病变是糖尿病的主要并发症，也是美国失明的主要原因。恢复视网膜功能的治疗方式相对无效。尽管已经报道了神经和血管视网膜的改变，但神经视网膜损伤和阻力小动脉的血管舒缩功能障碍之间的时间关系，阻力小动脉是调节血流的主要部位。 视网膜内部，仍不清楚。这一点很重要，因为早期糖尿病期间会出现视网膜血流量减少，这表明导致缺血的小动脉功能障碍可能会导致神经视网膜损伤。然而，导致糖尿病视网膜血管舒缩功能障碍的机制尚不清楚，这些机制适合在建立明显病理学之前进行治疗。此外，缺乏与人类视网膜微循环及其病理生理学相关的糖尿病动物模型的开发。为了解决这些临床上重要的问题，我们在猪中开发了链佐星诱导的 1 型糖尿病模型，我们已经证明该模型在视网膜血管舒缩调节/失调方面与人类相似。我们的初步数据显示，在糖尿病 2 周内，内皮依赖性一氧化氮 (NO) 介导的视网膜小动脉扩张受损，并且对大内皮素-1（内皮素转换酶-1 (ECE-1) 的内皮素-1 (ET-1) 前体底物）的收缩增强，但不改变对 ET-1 本身的收缩。尽管平滑肌对 ET-1 的反应未改变，但由于 ECE-1 表达升高，合成 ET-1 的能力增加。 ET-1 增加的潜在有害作用除了其有效的血管收缩作用外，还在于其抑制 NO 产生的能力。然而，ET-1 合成阻断是否可以改善糖尿病期间的扩张尚不清楚。由于糖尿病 2 周内视网膜乳酸水平升高，而糖尿病 6 周期间暗视 b 波振幅降低，而糖尿病 2 周则不然，因此看来促进缺血的血管舒缩功能障碍先于视网膜内神经损伤。我们最近在视网膜小动脉而非神经视网膜中检测到了ECE-1，因此ECE-1可能为早期糖尿病期间改善视网膜小动脉功能以及神经视网膜功能的二次改善提供特定的血管靶点。因此，本研究的目的是通过玻璃体内注射优化小干扰 RNA (siRNA) 的递送以恢复视网膜小动脉功能，从而了解 ET-1 系统在引发视网膜功能障碍中的作用。我们将检验以下假设：早期糖尿病会增强 ECE-1 活性和 ET-1 产生，导致在神经视网膜功能改变之前，内皮依赖性 NO 介导的视网膜小动脉扩张受损。为了支持这一假设并测试 siRNA 治疗的可行性，我们将追求以下具体目标：确定视网膜小动脉中 ECE-1 的分子敲低是否可以改善糖尿病引起的内皮和神经视网膜功能障碍。这项创新研究将首次对同一动物糖尿病期间视网膜的血管和神经功能进行纵向评估，这将有助于我们了解视网膜发病机制和开发早期治疗的新疗法。