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

项目总结 早产儿视网膜病变(ROP)是导致儿童失明的主要原因，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在亲属面前 因为他们的肺不成熟而导致高氧血症。高氧导致视网膜血管衰弱，从而导致 局部缺氧，然后刺激异常的代偿性新生血管(NV)。这一过程是由 血管内皮生长因子(VEGF)等生长因子表达改变。通过神经视网膜 已经被描述在ROP的促血管生成信号中发挥作用，但其机制仍然知之甚少。 目前治疗ROP的方法是治疗晚期视网膜新生血管，但不能解决视网膜神经功能障碍 ROP。在这项授权中，我们建议了解血管内皮生长因子的上游调节因子上皮膜的作用。 蛋白-2(EMP2)，在氧气诱导的小鼠视网膜病变模型中。 EMP2是一种对细胞间信号转导起重要作用的Tetraspanin膜蛋白，通过血管内皮生长因子和血管生成调节血管生成。 低氧诱导因子1α在部分癌症和胎盘疾病中的调节作用。我们假设 EMP2也是低氧介导的眼部病理性新生血管生成的调节因子。我们的 来自氧诱导视网膜病变(OIR)小鼠模型的初步数据表明，基因敲除 EMP2可减轻NV，抑制HIF1α和VEGFA在神经视网膜的表达。此外，OIR 诱导EMP2在神经视网膜的表达，在生理状态下，EMP2在神经视网膜中的表达较低 在RPE和角膜中高表达。然而，EMP2的表达及其在卵巢癌中的作用 神经视网膜的发育尚不清楚。这项提议的目标是确定时间和空间 EMP2在正常视网膜发育及OIR病理状态下的表达及功能因此， 我们试图了解EMP2调节神经视网膜血管生成信号的机制。我们 假设正常情况下分离于成年小鼠视网膜色素上皮(RPE)的EMP2表达 视网膜，在发育期OIR的神经视网膜细胞中增加(目标1)，在那里它直接调节HIF-1。 介导这些细胞产生血管内皮生长因子(目标2)。我们进一步假设抗体介导的靶向 EMP2将安全有效地减弱病理性新城疫病毒(目标3)。 我们的方法是多学科的，有新生儿/新生儿血管疾病，EMP2生物学， 视网膜疾病、基因组学和高级成像。我们将利用生化、生理、基因组和 光学成像方法在体内评估EMP2的表达、功能及下游血管生成效应。 这项研究的中心创新是：(1)进一步了解神经视网膜在氧气中的作用- 通过EMP2介导的血管生成生长因子产生诱导视网膜病变，以及(2)应用以下知识 EMP2的S通过血管内皮生长因子在肿瘤、胎盘和成人眼部疾病中的表达影响ROP。

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.