Induction of the blood-retinal barrier

描述（由申请人提供）：血视网膜屏障对正常视网膜功能至关重要，该屏障的丧失有助于早产儿视网膜病变、糖尿病视网膜病变、年龄相关性黄斑变性和其他视网膜疾病的病理生理。此外，病理性血管生成产生的高渗透性血管缺乏适当的血液-视网膜屏障。视网膜血管和视网膜色素上皮具有发育良好的紧密连接，控制液体和血溶质进入视网膜的流动。血视网膜屏障的血管成分的诱导发生在体内，通过内皮细胞与胶质细胞和周细胞的相互作用，并且可以用糖皮质激素诱导。然而，控制血视网膜屏障中紧密连接基因表达的分子机制仍未被广泛探索。我们的总体目标是了解屏障诱导的过程，以便开发新的治疗方法来恢复视网膜疾病的血视网膜屏障，同时减少不良反应。claudin和occludin是跨膜紧密连接蛋白，对血视网膜屏障的形成和调节是必需的。claudin-5对血视网膜屏障特别重要，因为这种claudin主要局限于脉管系统，基因缺失研究表明claudin-5是血脑和血视网膜屏障的重要组成部分。Occludin含量与屏障完整性密切相关，而Occludin磷酸化与通透性增加有关。我们之前的研究表明，糖皮质激素诱导claudin-5和occludin的基因表达，促进屏障的完整性。此外，一种新的顺式元件称为闭塞蛋白增强元件或OEE控制糖皮质激素诱导闭塞蛋白基因表达。在这个提议中，我们假设一种新的反式作用转录因子与OEE相互作用，诱导内皮细胞屏障。这些研究将确定OEE元件对糖皮质激素控制cludin -5基因表达的贡献，研究OEE元件对紧密连接基因RPE表达的贡献，最重要的是，确定通过OEE控制紧密连接基因表达的反式作用因子。这些研究将引导未来的研究，阐明发育过程中屏障诱导的机制，并推进新的治疗方法，以恢复疾病状态下的血液-视网膜屏障。公共卫生相关性：血液-视网膜屏障对正常视网膜功能至关重要，该屏障的丧失有助于早产儿视网膜病变、糖尿病视网膜病变、年龄相关性黄斑变性和其他视网膜疾病的病理生理学。此外，病理性血管生成导致高渗透性血管缺乏适当的血液-视网膜屏障。在这个应用中，我们提出了一种新的分子机制来控制血液视网膜屏障的诱导。了解这一机制将带来新的治疗方法来恢复视网膜血管疾病的血视网膜屏障，并且副作用有限。

DESCRIPTION (provided by applicant): The blood-retinal barrier is essential for normal retinal function and loss of this barrier contributes to the pathophysiology of retinopathy of prematurity, diabetic retinopathy, age related macular degeneration and other retinal diseases. Further, pathological angiogenesis produces highly permeable vessels that lack a proper blood-retinal barrier. The blood vessels of the retina and the retinal pigment epithelium possess well-developed tight junctions that control the flow of fluids and blood-borne solutes into the retina. Induction of the vascular component of the blood-retinal barrier occurs through endothelial interaction with glia and pericytes in vivo and may be induced pharmacologically with glucocorticoids. However, the molecular mechanisms that control tight junction gene expression in the blood-retinal barrier remain largely unexplored. Our overall goal is to understand the process of barrier induction so that novel therapies may be developed to restore the blood-retinal barrier in retinal diseases with limited adverse side effects. The claudins and occludin are transmembrane tight junction proteins necessary for proper formation and regulation of the blood-retinal barrier. Claudin-5 is particularly important to the blood-retinal barrier since this claudin is largely restricted to the vasculature and gene deletion studies have demonstrated claudin-5 is an essential component of the blood-brain and blood-retinal barrier. Occludin content correlates well with barrier integrity, whereas occludin phosphorylation is associated with increased permeability. Our previous studies have demonstrated that glucocorticoids induce gene expression of claudin-5 and occludin and promote barrier integrity. Further, a novel cis-element termed the occludin enhancer element or OEE controls glucocorticoid induction of occludin gene expression. In this proposal we hypothesize that a novel trans-acting transcription factor interacts with the OEE to induce the endothelial cell barrier. These studies will determine the contribution of the OEE element to glucocorticoid control of claudin-5 gene expression, investigate the contribution of the OEE element to RPE expression of tight junction genes and, most importantly, identify the trans-acting factor that controls tight junction gene expression through the OEE. These studies will lead to future investigations that will elucidate the mechanisms of barrier induction during development and advance novel therapies to restore the blood-retinal barrier in disease states. PUBLIC HEALTH RELEVANCE: The blood-retinal barrier is essential for normal retinal function and loss of this barrier contributes to the pathophysiology of retinopathy of prematurity, diabetic retinopathy, age related macular degeneration and other retinal diseases. Further, pathological angiogenesis leads to highly permeable vessels that lack a proper blood-retinal barrier. In this application, we propose a novel molecular mechanism exists to control induction of the blood retinal-barrier. Understanding this mechanism will lead to new therapies to restore the blood-retinal barrier in retinal vascular diseases, with limited side effects.