Effects of systemic disease on corneal epithelial pathophysiology

项目总结 糖尿病引起的角膜并发症很常见，通常非常痛苦，会对生活质量产生负面影响，而且 导致永久性视力损伤。由于大量的分子通路在 糖尿病的角膜，传统的治疗方法往往是不够的，因为异常的细胞反应和丢失 来自角膜神经的营养支持。 我们先前的研究表明，糖尿病患者的胰岛素样生长因子(IGF)系统发生了改变。这 包括糖尿病患者多效性分泌蛋白IGF结合蛋白-3(IGFBP-3)的显著增加 与角膜基底下神经丛丢失相关的人类泪水。而角膜上皮细胞则不能 需要胰岛素才能摄取葡萄糖，我们的实验室发现，胰岛素在 调节胰岛素样生长因子1型受体(IGF-1R)、胰岛素受体(INSR)和IGFBP-3的表达。进一步 对这些途径的询问导致在角膜上皮细胞中产生了新的和令人兴奋的发现 (CECs)构成当前提案的基础。与这项提议高度相关，我们所有的发现 提示IGF-1系统是线粒体功能和稳定性的中介。这在临床上具有重要意义 由于线粒体损伤是糖尿病和其他疾病发病率的主要潜在原因 系统性疾病。 基于这些发现，我们建议检验两个中心假设：(1)胰岛素和IGFBP-3调节 通过协调线粒体-核串扰响应来控制线粒体质量和稳定性 应激；以及，(2)电压依赖的阴离子通道VDAC1、IGF-1R和 INSR介导线粒体的生物发生和稳定性。我们将在以下目标中检验这些假设。 目的1.比较胰岛素样生长因子相关配体、受体和IGFBP-3对信号、增殖和生长的影响。 正常血糖与高血糖CEC体外培养及糖尿病小鼠角膜的代谢 活体上皮细胞。目的2：比较胰岛素样生长因子相关配体、受体和IGFBP-3对线粒体的作用 与VDAC1相互作用的生物发生、稳定性和体外CECs的动力学(分裂/融合) 糖尿病小鼠体内角膜上皮细胞。目的3：比较胰岛素样生长因子相关配体、受体和 IGFBP-3对体外培养的CECs和体内糖尿病小鼠角膜上皮细胞有丝分裂和凋亡的影响 众所周知，线粒体调节驱动能量产生和细胞生存的信号，而它们的 功能障碍与一系列疾病有关。这些研究将提供第一个 详细介绍了IGF家族在调节线粒体稳定性和功能中的作用 健康的角膜和疾病的病理生物学。这些结果可能代表着一种重大的范式转变 在我们对糖尿病角膜上皮和其他角膜的认识和未来的治疗中 线粒体功能改变的疾病和营养不良。

PROJECT SUMMARY Corneal complications from diabetes are common, often very painful, can negatively impact quality of life, and lead to permanent visual impairment. Owing to the vast array of molecular pathways that are altered in the diabetic cornea, traditional therapies are often not sufficient, due to abnormal cellular responses and the loss of trophic support from corneal nerves. Our prior studies have shown that the insulin-like growth factor (IGF) system is altered in diabetes. This includes a significant increase in the pleiotropic secretory protein, IGF-binding protein-3 (IGFBP-3) in diabetic human tears that correlates with loss of the corneal subbasal nerve plexus. While corneal epithelial cells do not require insulin for glucose uptake, our laboratory has found instead that insulin has an essential role in mediating expression of the IGF type 1 receptor (IGF-1R), insulin receptor (INSR), and IGFBP-3. Further interrogation of these pathways led to the generation of novel and exciting findings in corneal epithelial cells (CECs) that form the basis for the current proposal. Of high relevance to this proposal, all of our findings implicate the IGF-1 system as a mediator of mitochondrial function and stability. This is clinically significant since mitochondrial damage is a major underlying cause of disease morbidity in diabetes and other systemic diseases. Based on these findings, we propose to test two central hypotheses: (1) that insulin and IGFBP-3 regulate mitochondrial quality control and stability by coordinating mitochondrial-nuclear crosstalk in response to stress; and, (2) that interactions between the voltage dependent anion channel VDAC1, IGF-1R, and INSR mediate mitochondrial biogenesis and stability. We will test these hypotheses in the following aims. Aim 1. Compare the effects of IGF-related ligands, receptors, and IGFBP-3 on signaling, proliferation, and metabolism in normoglycemic versus hyperglycemic CEC culture in vitro and the diabetic mouse corneal epithelium in vivo. Aim 2: Compare the effects of IGF-related ligands, receptors, and IGFBP-3 on mitochondrial biogenesis, stability through interactions with VDAC1, and dynamics (fission/fusion) in CECs in vitro and the diabetic mouse corneal epithelium in vivo. Aim 3: Compare the effects of IGF-related ligands, receptors, and IGFBP-3 on mitophagy and apoptosis in CECs in vitro and the diabetic mouse corneal epithelium in vivo. Mitochondria are well known to regulate signals that drive energy production and cell survival, and their dysfunction has been implicated in a wide range of diseases. These studies will provide the first comprehensive picture detailing the role of the IGF family in mediating mitochondrial stability and function in the healthy cornea and in the pathobiology of disease. The outcomes could represent a major paradigm shift in our understanding and future treatment of the diabetic corneal epithelium and other corneal diseases and dystrophies where mitochondrial function is altered.