Effects of systemic disease on corneal epithelial pathophysiology

 描述（由申请人提供）：糖尿病引起的眼部并发症是美国失明的主要原因。在接下来的几十年中，预计2型糖尿病（T2 DM）引起的并发症的患病率将上升，增加了该疾病的经济负担。该提案的目标是：（1）确定导致疼痛且通常难治的糖尿病角膜疾病的病理生理学机制;（2）鉴定用于在糖尿病角膜疾病发作前检测高危患者的生物标志物。 威胁视力的眼病。本研究将验证三个新的假说：（1）IGF-1和胰岛素通过调节Hybrid-R、IGF-1 R和INSR介导质膜和细胞核中不同的事件。(2)炎症和氧化应激水平的增加，以及角膜神经营养支持的丧失，导致Hybrid-R表达和功能异常。(3)除了调节Hybrid-R外，泪液中IGF相关蛋白量的变化代表了潜在的生物标志物，可用于识别T2 DM中存在显著眼部病理学风险的患者。我们将在以下三个目标中测试这些假设：目标1：（A）评估控制角膜上皮细胞中Hybrid-R形成、胰岛素敏感性和GSK 3 β活性的特定因素。(B)确定Hybrid-R、IGF-1 R和INSR的核靶点。目的2：（A）测试IGF-1、IGF-II、胰岛素和IGFBP 3对角膜上皮细胞的作用 以及在炎性介质和高血糖诱导的氧化应激存在下的神经纤维损失。(B)表征T2 DM对Hybrid-R介导的基因调控的影响，并与角膜基底下神经丛和原位末端上皮神经中的糖尿病相关变化相关。目标3：使用新的定量微量生化分析、体内共聚焦显微镜（IVCM）以及角膜和视网膜疾病的临床标志物，确定T2 DM患者泪液中IGF-1、胰岛素和IGFBP 3水平是否与角膜和视网膜病理学相关。这些目标将通过体外培养模型、原位人体组织分析和体内临床研究的组合来实现，以研究T2 DM的病理生理学效应如何影响角膜神经的形态、泪膜的生理学和角膜上皮。这将是第一个研究Hybrid-R在糖尿病角膜病变中的作用。这些研究还提出了角膜疾病中局部胰岛素信号受损的新生物学机制。其他实验室专注于糖尿病伤口愈合受损。我们的重点是确定导致角膜损伤的关键机制;表征和验证泪膜衍生的生物标志物，这些生物标志物将允许早期干预方法来预防糖尿病相关的视力丧失。

 DESCRIPTION (provided by applicant): Ocular complications from diabetes are a leading cause of blindness in the United States. Throughout the next few decades, the prevalence of complications stemming from Type 2 Diabetes Mellitus (T2DM) is expected to rise, increasing the economic burden of the disease. The goals of this proposal are: (1) to define the pathophysiological mechanisms that result in painful and often refractory diabetic corneal disease and; (2) to identify biomarkers for use in detecting at-risk patients prior to the onset of sight threatening ocular disease. This proposal will test three novel hypotheses: (1) That IGF-1 and insulin mediate distinct events at the plasma membrane and in the nucleus through regulation of Hybrid-R, IGF-1R and INSR. (2) That increasing levels of inflammation and oxidative stress, and a loss of trophic support from corneal nerves, results in aberrant Hybrid-R expression and function. (3) That, in addition to regulating Hybrid-R, changes in the amount of IGF-related proteins in tears represent potential biomarkers to identify patients at-risk for significant ocular pathology in T2DM. We will test these hypotheses in the following three aims: Aim 1: (A) Evaluate specific factors that control Hybrid-R formation, insulin sensitivity and GSK3 beta activity in corneal epithelial cells. (B) Identify nuclear targets for Hybrid-R, IGF-1R, and INSR. Aim 2: (A) Test the effects of IGF-1, IGF-II, insulin, and IGFBP3 on corneal epithelial cells and nerve fiber loss in the presence of inflammatory mediators and hyperglycemia-induced oxidative stress. (B) Characterize the effects of T2DM on Hybrid-R mediated gene regulation and correlate with diabetes-related changes in the corneal subbasal nerve plexus and terminal epithelial nerves in situ. Aim 3: Determine whether tear levels of IGF-1, insulin and IGFBP3 in human patients with T2DM correlate with corneal and retinal pathology, using new quantitative microvolume biochemical assays, in vivo confocal microscopy (IVCM), and clinical markers of corneal and retinal disease. These aims will be accomplished using a combination of in vitro culture models, in situ human tissue analysis, and in vivo clinical studies to investigate how the pathophysiological effects from T2DM impacts the morphology of corneal nerves, the physiology of the tear film, and the corneal epithelium. These will be the first studies to investigate a rolefor the Hybrid-R in mediating corneal disease in diabetes. These studies also propose a novel biological mechanism for impaired local insulin signaling in corneal disease. Other laboratories are focused on impaired wound healing in diabetes. Our focus is on identifying key mechanisms that contribute to corneal damage; and characterizing and validating tear-film derived biomarkers that will allow for early, interventional approaches to prevent diabetes-related vision loss.