Molecular mechanisms in steroid-induced glaucoma.

描述(申请人提供)：已知糖皮质激素可引起人类眼压升高。这种引起的高眼压会导致青光眼视力丧失。类固醇诱导的青光眼在过去几年中变得更加普遍，因为许多后极部疾病越来越多地被有效、持久的类固醇制剂治疗。激素性开角型青光眼是由于小梁网(TM)流出功能降低所致。在组织和/或器官培养中，已经研究了导致流出能力下降的细胞和分子机制。然而，尽管我们对这种疾病的认识有了很大的进步，但我们仍然不完全了解导致激素性眼压下降和由此导致的眼压升高的分子机制。在过去的几年里，我们已经建立了两种动物模型(牛和羊)来研究体内激素性青光眼，并使用其中一种来深入了解疾病的发病机制。在这个项目中，我们建议使用绵羊类固醇诱导的眼压升高模型来剖析这种疾病的分子机制。我们的总体假设是，类固醇诱导的小梁网基因和蛋白表达的变化导致流出途径的改变，最终导致流出便利程度和眼压升高的减少。因此，我们提出了以下具体目标：1.明确一些关键基因在激素性眼压升高的多个相互连接网络中的作用。我们的假设是，这些紧密相连的基因网络介导了类固醇诱导的机动性和眼压的变化。因此，这些网络的特定扰动将改善或防止类固醇诱导的眼压升高的发展。2.研究激素性高眼压形成过程中TM基因表达变化的时程变化。我们的假设预测，属于有限数量的网络的一小部分基因是类固醇治疗的初始反应，它们表达的变化最终会导致小梁网络的变化，从而导致流出能力和眼压升高的减少。3.通过蛋白质组学分析检测激素性高眼压形成过程中的蛋白质变化。我们的假设是，翻译后修饰(如磷酸化或糖基化)改变了影响类固醇诱导的眼压升高和青光眼发病的通路中关键分子的活性。该项目有望明确类固醇诱导青光眼的药物干预靶点。此外，由于激素性青光眼与慢性开角型青光眼的相似之处，我们期望在这个项目中获得的知识将有助于阐明后一种情况的一些病理生理机制。 公共卫生相关性：类固醇诱导的青光眼是一种潜在的致盲疾病，可影响使用类固醇治疗的易感人群。在过去的几年里，随着许多后遗症越来越多地被有效的、持久的类固醇制剂治疗，它变得更加普遍。该项目有望为激素性青光眼的药物干预确定靶点，并提供可能用于理解和治疗原发性开角型青光眼的知识。

DESCRIPTION (provided by applicant): Glucocorticosteroids are known to cause intraocular pressure (IOP) elevation in humans. This induced ocular hypertension can lead to glaucomatous visual loss. Steroid-induced glaucoma has over the past few years become more prevalent as many posterior pole conditions are increasingly been treated with potent, long-lasting steroid preparations. Steroid-induced open angle glaucoma is caused by a decrease of trabecular meshwork (TM) outflow facility. Cellular and molecular mechanisms underlying this decrease in outflow facility have been studied in tissue and/or organ culture. However, despite significant advances to our understanding of this disease, we still do not fully understand the molecular mechanisms that lead to steroid induced decrease in facility and the resulting IOP elevation. Over the past few years we have developed two animal models (bovine and ovine) for the study of steroid-induced glaucoma in-vivo and have used one of them to gain some insight into the pathogenesis of the disease. In this project we propose to use the ovine steroid-induced IOP elevation model to dissect the molecular mechanisms of this disease. Our overall hypothesis is that steroid-induced changes of gene and protein expression in the trabecular meshwork (TM) lead to changes in the outflow pathways which ultimately cause a reduction in outflow facility and IOP elevation. We thus propose the following specific aims: 1. To define the role of key genes in a number of inter-connecting networks in steroid induced IOP elevation. Our hypothesis is that these closely linked gene networks mediate the steroid-induced changes in facility and IOP. Thus specific perturbation of these networks will ameliorate or prevent the development of steroid- induced IOP elevation. 2. To study the time-course of gene expression changes those occur in the TM during the development of steroid-induced IOP elevation. Our hypothesis predicts that a small set of genes that belong to a limited number of networks are the initial response to steroid therapy and that changes in their expression ultimately causes changes in the trabecular meshwork that lead to a reduction in outflow facility and IOP elevation. 3. To detect (by proteomic analysis) protein changes those occur during the development of steroid-induced IOP elevation. Our hypothesis is that post-translational modifications (like phosphorylation or glycosylation) modify the activity of key molecules in pathways that affect the development of steroid-induced IOP elevation and the onset of glaucoma. This project is expected to define targets for pharmacologic intervention in steroid-induced glaucoma. In addition, and because of the similarities of steroid-induced with chronic open angle glaucoma, we expect that knowledge gained during this project will help to elucidate some of the pathophysiology of the latter condition as well. PUBLIC HEALTH RELEVANCE: Steroid-induced glaucoma is a potentially blinding disease that can affect susceptible individuals treated with steroids. Over the past few years it has become more prevalent as many posterior pole conditions are increasingly been treated with potent, long-lasting steroid preparations. This project is expected to define targets for pharmacologic intervention in steroid-induced glaucoma and provide knowledge that can potentially be used to understand and treat primary open angle glaucoma as well.