Targeting epithelial membrane protein 2 (EMP2) in retinopathy of prematurity

项目摘要 早产儿视网膜病变（ROP）是儿童失明的主要原因，影响约1/3-4 极低出生体重早产儿早产需要将这些新生儿暴露于相对 因为他们的肺不成熟而导致高氧。高氧导致视网膜中的血管衰减，这导致 局部缺氧，然后刺激异常的代偿性新生血管形成（NV）。这一过程是由 生长因子如血管内皮生长因子（VEGF）的表达改变。虽然神经视网膜 已被描述为在ROP中的促血管生成信号传导中起作用，但其机制仍知之甚少。 目前用于ROP的疗法治疗晚期视网膜新生血管，并且不能解决视网膜神经功能障碍。 ROP。在这项研究中，我们打算了解VEGF的上游调节因子，上皮细胞膜， 蛋白-2（EMP 2），在氧诱导的视网膜病变小鼠模型中。 EMP 2是一种对细胞间信号传导很重要的四跨膜蛋白，通过VEGF调节血管生成， 低氧诱导因子（HIF）1α在某些癌症和胎盘疾病中调节作用我们假设 EMP 2也作为眼睛中缺氧介导的病理性新血管生成的调节剂。我们 来自氧诱导视网膜病变（OIR）小鼠模型的初步数据表明， EMP 2可减弱NV并抑制HIF 1 α和VEGFA在神经视网膜中的表达。此外，OIR 诱导EMP 2在神经视网膜中表达，而在生理状态下，EMP 2在神经视网膜中低表达 并且在RPE和角膜中高表达。然而，EMP 2表达的作用及其在肿瘤中的功能尚不清楚。 神经视网膜的发育是未知的。该提案的目标是确定时间和空间 EMP 2在正常视网膜发育以及OIR病理状态中的表达和功能。因此， 我们试图了解EMP 2调节神经视网膜血管生成信号的机制。我们 假设EMP 2表达，通常在成年小鼠视网膜色素上皮（RPE）中分离 在发育中的眼睛中，在OIR中的神经视网膜细胞中增加（Aim 1），在那里它直接调节HIF-1。 介导的VEGF从这些细胞中产生（目的2）。我们进一步假设，抗体介导的靶向 EMP 2将安全有效地减弱病理性NV（目的3）。 我们的方法是多学科的，专家在新生儿血管病/血管疾病，EMP 2生物学， 视网膜疾病、基因组学和高级成像。我们将利用生物化学，生理学，基因组学， 体内光学成像方法来评估EMP 2表达、功能和下游血管生成效应。 本研究的主要创新之处在于：（1）进一步了解了神经视网膜在氧气中的作用; 通过EMP 2介导的血管生成生长因子的产生诱导视网膜病变，以及（2）应用以下知识： EMP 2通过VEGF表达在癌症、胎盘形成和成人眼病中对ROP的血管生成的影响。

PROJECT SUMMARY Retinopathy of prematurity (ROP) is a leading cause of childhood blindness, affecting approximately 1 in 3-4 extremely low birth weight premature infants. Preterm delivery requires exposing these neonates to relative hyperoxia because of their lung immaturity. Hyperoxia leads to vessel attenuation in the retina, which results in local hypoxia, which then fuels abnormal compensatory neovascularization (NV). This process is mediated by altered expression of growth factors such as vascular endothelial growth factor (VEGF). Though the neuroretina has been described to play a role in pro-angiogenic signaling in ROP, the mechanisms remain poorly understood. Current therapies for ROP treat late retinal neovascularization and do not address neuroretinal dysfunction in ROP. In this grant, we propose to understand the role of an upstream regulator of VEGF, epithelial membrane protein-2 (EMP2), in an oxygen-induced murine model of retinopathy. EMP2, a tetraspanin membrane protein important for cell-to-cell signaling, regulates angiogenesis via VEGF and hypoxia inducible factor (HIF)1α modulation in select cancers and placental diseases. We hypothesize that EMP2 serves as a regulator of hypoxia-mediated pathological neoangiogenesis in the eye as well. Our preliminary data from a mouse model of oxygen-induced retinopathy (OIR) demonstrates that genetic knock out of EMP2 attenuates NV and suppresses HIF1α and VEGFA expression in the neuroretina. Moreover, OIR induces EMP2 expression in the neuroretina, which in physiologic states, has low expression in the neuroretina and high expression in the RPE and cornea. However, the role for EMP2 expression and its function in the developing neuroretina is unknown. The goals of this proposal are to determine the temporal and spatial expression and function of EMP2 in normal retinal development as well as in pathologic conditions of OIR. Thus, we seek to understand the mechanisms by which EMP2 regulates neuroretinal angiogenic signaling. We hypothesize that EMP2 expression, normally isolated to the retinal pigment epithelium (RPE) in the adult mouse retina, is increased in neuroretinal cells in OIR in the developing eye (Aim 1), where it directly regulates HIF- mediated VEGF production from these cells (Aim 2). We further hypothesize that antibody-mediated targeting of EMP2 will safely and effectively attenuate pathologic NV (Aim 3). Our approach is multidisciplinary, with experts in neonatology/vascular disease in neonates, EMP2 biology, retinal diseases, genomics, and advanced imaging. We will utilize biochemical, physiological, genomic, and optical imaging methods in vivo to assess EMP2 expression, function, and the downstream angiogenic effect. The central innovations of this study are to: (1) further our understanding of the neuroretina’s role in oxygen- induced retinopathy via EMP2-mediated angiogenic growth factor production, and (2) apply the knowledge of EMP2’s effects on angiogenesis via VEGF expression in cancer, placentation, and adult eye disease to ROP.