Racial disparities of open angle glaucoma: A study of mitochondria and oxidative stress in human trabecular meshwork

项目摘要： 青光眼是世界范围内致盲的主要原因，了解青光眼的发病机制是一个重要的目标 视觉研究。许多基于人口的研究表明，非洲人后裔 在较早的年龄患上青光眼，严重程度和失明风险增加。许多研究 确定了小梁网（TM）细胞的氧化损伤，导致流出功能降低， 眼内压升高。尽管将氧化损伤与青光眼联系起来的证据很强， 青光眼中氧化损伤的原因尚不清楚。在拟议的研究中，我们将测试假设 TM的氧化损伤与氧的基本遗传和生理差异有关 基于种族背景，代谢导致青光眼的差异。我们的假设是基于 在手术过程中在人眼中进行的氧分压（pO 2）的眼内测量。我们 确定了pO 2与青光眼的重要风险因素之间的强相关性，包括中央角膜 厚度和非洲裔美国人/黑人（B）的遗产。此外，DNA的细胞标记物的测量 与W组相比，B组严重青光眼患者的房水中氧化损伤水平升高 患者与W细胞相比，来自B健康供体的培养的TM细胞具有改变的能量（ATP）， 活性氧的产生，涉及能量处理细胞器，线粒体。我们 具体目标将测试这些假设：（目标1）将评估B之间TM基因表达的差异 和W供体对照以及不同青光眼阶段的患者，以确定 组织功能（控制眼压）和对损伤敏感性的差异。感兴趣的基因将 进一步研究（RT-qPCR，原位杂交）和描绘蛋白质表达（Western印迹）， 组织和潜在的生物学途径，重点是线粒体功能，氧化应激和 抗氧化保护(Aim 2A）将研究来自以下的原代人TM细胞培养物中的线粒体功能： B和W健康供体对照和不同严重程度阶段的青光眼患者的样本。我们将 确定种族差异和暴露于不同水平的pO 2对详细分析的影响， 线粒体数量和功能、活性氧水平和抗氧化保护。(Aim 2B） 还将评估潜在抗氧化疗法的细胞效应。建议的研究是创新的 因为了解这些生理机制可能会导致疾病差异， 通过血液和组织祖先基因分型和线粒体DNA单倍型群证实， 分层，将提供有关开角型青光眼的病理生理学的重要信息， 确定导致TM功能障碍和房水流出功能丧失的因素。知识 这些研究的成果可能会导致新的治疗方法和策略，以防止这种致盲性疾病。

Project Abstract: Understanding the pathogenesis of glaucoma, a leading cause of blindness worldwide, is an important goal of vision research. As indicated in numerous population-based studies, individuals of African descent develop glaucoma at an earlier age with increased severity and risk of blindness. Many studies have identified oxidative damage to the trabecular meshwork (TM) cells, leading to decreased outflow facility and increased intraocular pressure. Although the evidence linking oxidative damage to glaucoma is strong, the causes of oxidative damage in glaucoma are not known. In the proposed studies, we will test the hypothesis that oxidative damage to the TM is associated with basic genetic and physiologic differences in oxygen metabolism leading to disparities in glaucoma based on racial background. Our hypothesis is based on intraocular measurements of oxygen partial pressure (pO2) made in the human eye during surgery. We identified strong correlations between pO2 and important risk factors for glaucoma, including central corneal thickness and African-American/Black (B) heritage. In addition, measurements of a cell marker for DNA oxidative damage were elevated in the aqueous humor of B patients with severe glaucoma compared to W patients. Cultured TM cells from B healthy donors compared to W cells had altered energy (ATP) and reactive oxygen species production, implicating the energy processing organelles, the mitochondria. Our specific aims will test these hypotheses: (Aim 1) will evaluate differences in TM gene expression between B and W donor controls and in patients at various glaucoma stages in order to identify the genetic basis of disparities in tissue function (controlling eye pressure) and susceptibility to damage. Genes of interest will be further studied (RT-qPCR, in situ hybridization) and delineate protein expression (Western blot) in the tissue and potential biological pathways involved, focusing on mitochondrial function, oxidative stress and antioxidant protection. (Aim 2A) will study mitochondrial functions in primary human TM cell cultures from specimens of B and W healthy donor controls and glaucoma patients at various severity stages. We will determine the effects of racial differences and exposure to varying levels of pO2 on detailed analyses of mitochondrial quantities and function, reactive oxygen species levels and antioxidant protection. (Aim 2B) will also assess the cellular effects of potential antioxidative therapies. The proposed research is innovative because understanding these physiological mechanisms potentially contributing to disease disparity based on racial ancestry, confirmed by blood and tissue ancestral genotyping and mitochondrial DNA haplogroup stratification, will provide important information about the pathophysiology of open angle glaucoma by identifying factors responsible for the TM dysfunction and loss of aqueous outflow facility. The knowledge gained in these studies may lead to new therapies and strategies to prevent this blinding disease.