The Pathomechanistic Role of Endothelial IDO in proliferative Retinopathy

描述（由申请人提供）：早产儿视网膜病变（PR），包括早产儿视网膜病变（ROP）和增殖性糖尿病视网膜病变（DR），是儿童和工作年龄成人失明的主要原因。尽管PR的特征在于病理性视网膜血管过度增殖或新血管形成，但旨在特异性抑制血管内皮生长因子（VEGF）产生的疗法未能持续改善临床结局。这一观察结果清楚地表明，其他分子因素/途径有助于PR中的病理性视网膜新生血管形成，因此可能是可行的治疗靶点。在这方面，我们对我们的初步发现很感兴趣，即在DR患者的玻璃体中以及在经历氧诱导视网膜病变（OIR）的小鼠幼仔的视网膜新生血管内皮中存在强吲哚胺-2，3-双加氧酶（IDO）表达。此外，在体外实验中，我们发现IDO的上调赋予血管内皮细胞（EC）独立于VEGF的增殖、迁移和管形成的能力增强。根据这些新的发现，我们假设内皮IDO具有促血管生成活性，并且这种酶的靶向抑制将阻断PR中的病理性视网膜血管生成/新生血管形成。为了检验这一假设，我们将使用许多独特的方法，包括稳定的IDO过表达视网膜血管EC系和基于睡美人（SB）的非病毒基因整合策略，体内视网膜EC内持续的人IDO（hIDO）转基因表达。在具体目标1中，我们将评估内皮细胞的促血管生成活性。 IDO在体外和体内，重点是IDO诱导的视网膜EC从正常状态到促血管生成状态的表型转换背后的分子机制。在具体目标2中，我们将检查视网膜内皮IDO的药理学抑制在预防实验性PR中的治疗潜力。在这些研究中，我们寻求使用选择性IDO抑制剂1-甲基-DL-色氨酸（1-mT）实现治疗目标，一种小分子化学品（分子量218），其可以口服或腹膜内施用，并且目前用于抗癌临床试验，具有令人满意的安全性。总的来说，这项提案解决了PR治疗中的一个关键科学空白，如果证明有效，可能会快速进入1期临床试验。

DESCRIPTION (provided by applicant): Proliferative retinopathy (PR), which includes retinopathy of prematurity (ROP) and proliferative diabetic retinopathy (DR), represent a leading cause of blindness in both children and working-age adults. Although PR is characterized by pathological retinal vascular overproliferation or neovascularization, therapies aimed at specifically inhibiting production of vascular endothelial growth factor (VEGF) have failed to consistently improve clinical outcomes. This observation clearly indicates that additional molecular factors/pathways contribute to pathological retinal neovascularization in PR and may thus be viable therapeutic targets. In this regard, we became intrigued by our preliminary finding that strong indoleamine-2,3-dioxygenase (IDO) expression is present in the vitreous of patients with DR as well as in the endothelium of retinal neovessels from mouse pups undergoing oxygen-induced retinopathy (OIR). Further, in in vitro experiments, we found that up-regulation of IDO endows the vascular endothelial cells (ECs) with enhanced capacity for proliferation, migration and tube formation independently of VEGF. In light of these novel findings we hypothesize that that endothelial IDO possesses pro-angiogenic activity, and that targeted inhibition of this enzyme will block the pathological retinal angiogenesis/neovascularization in PR. To test this hypothesis, we will use a number of unique approaches, which include a stable IDO-overexpressing retinal vascular EC line and the Sleeping- Beauty (SB)-based nonviral gene integrating strategy capable of long-lasting human IDO (hIDO) transgene expression within retinal ECs in vivo. In Specific Aim 1, we will evaluate the pro-angiogenic activity of endothelial IDO in vitro and in vivo, with a focus on the the molecular mechanism(s) behind IDO-induced phenotypic switching of retinal ECs from a normal to a pro-angiogenic state. In Specific Aim 2, we will examine the therapeutic potential of pharmacological inhibition of retinal endothelial IDO in the prevention of experimental PR. In these studies, we seek to achieve the therapeutic goal using selective IDO inhibitor 1-metheyl-DL-tryptophan (1-mT), a small molecular chemical (molecular weight 218) that can be orally or intraperitoneally administered and is currently used in anti-cancer clinical trials with satisfactory safety profile. Taken together, this proposal addresses a critical scientific gap in the treatment of PR, and if proven effective, may be fast-tracked to a phase 1 clinical trial.