Identification of Retinoid-Binding Protein 3 (RBP3): A Protective Factor against Diabetic Retinopathy Using Retina from People with Extreme Duration of Diabetes

 描述(申请人提供)：糖尿病视网膜病变(DR)是发达国家导致视力丧失的主要原因，90%的1型糖尿病患者(T1 DM)病程至少15年。激光光凝和抗血管内皮生长因子药物等治疗方法通常能够治疗增殖性糖尿病视网膜病变(PDR)和黄斑水肿；然而，基于高血糖的机制对早期DR的临床治疗并不成功。由于流行病学观察到Joslin 50年奖牌获得者研究队列(n&gt；900)，一个有50年或更长时间的T1 DM的组，尽管早期血糖控制工具有限，但没有发生严重的DR(患病率35%)，我们专注于寻找内源性视网膜保护因素。利用视网膜和玻璃体的蛋白质组学分析，发现即使在高血糖存在的情况下，非轻度DR奖牌获得者的视黄醇结合蛋白-3(RBP3)也比PDR患者升高。初步数据显示，在T1D和T2D患者中，与活动期或静止期PDR相比，非轻度DR患者玻璃体中RBP3升高的模式是一致的。纯化的RBP3抑制高血糖和血管内皮生长因子对视网膜内皮细胞和周细胞的作用。有趣的是，纯化的RBP3在纳摩尔浓度下刺激周细胞和内皮细胞中p-AKT和p-Erk的信号级联。视网膜下注射慢病毒过表达RBP3可阻止糖尿病大鼠视网膜毛细血管通透性和血管内皮生长因子表达的增加、视网膜ERG和OCT检测的神经视网膜功能障碍、无细胞毛细血管的形成和周细胞的凋亡，所有这些都表明RBP3蛋白具有保护作用。这些研究表明，RBP3除了在光感受器和视网膜色素上皮细胞之间运输维甲酸外，还有其他功能。为了证实RBP3在视网膜中对高血糖的不良影响具有新的保护作用，我们提出了三个特定的目标：具体目标1：评估非糖尿病对照组、不同病程、年龄、糖尿病视网膜病变严重程度和血糖控制的1型和2型糖尿病患者玻璃体和房水中RBP3的水平。具体目的2：确定提高视网膜或玻璃体中RBP3的水平是否能减少糖尿病引起的啮齿动物视网膜或血管异常。特异目的3：研究视网膜周细胞和内皮细胞中Rbp3的S信号和作用。

 DESCRIPTION (provided by applicant): Diabetic retinopathy (DR) is the leading cause of vision loss in developed countries and affects 90% of type 1 diabetic patients (T1DM) with at least 15 years disease duration. Treatments such as laser photocoagulation and anti-VEGF agents are often able to treat proliferative diabetic retinopathy (PDR) and macular edema; however, clinical treatment for early stages of DR based on the mechanisms attributed to hyperglycemia have not been successful. Due to the epidemiological observation that the Joslin 50-Year Medalist Study cohort (n>900), a group with 50 or more years of T1DM, did not develop severe DR (prevalence 35%) despite limited early tools for glycemic control, we focused on finding an endogenous retinal protective factor. Using proteomic analysis of the retina and vitreous, retinoid binding protein-3 (RBP3) was found to be elevated in those Medalists with no-mild DR compared to those with PDR even in the presence of hyperglycemia. Preliminary data showed that this pattern of RBP3 elevation in the vitreous with no-mild DR compared to active or quiescent PDR is consistent in both T1D and T2D patients. Purified RBP3 inhibited the actions of hyperglycemia and VEGF on retinal endothelial cells and pericytes. Interestingly, purified RBP3 stimulated signaling cascades of p-AKT and p-ErK in pericytes and endothelial cells at nanomolar concentrations. Overexpression of RBP3 by subretinal injections of lentivirus prevented increases in capillary permeability and VEGF expression, neural retinal dysfunction measured by ERG and OCT, the formation of acellular capillaries and pericyte apoptosis in diabetic Lewis rats, all suggest the protective ability of the RBP3 protein. These studies suggest that RBP3 has functions other than transporting retinoids between photoreceptors and retinal pigmented epithelial cells. To confirm that RBP3 could have protective and novel actions in the retina against the adverse effects of hyperglycemia, we propose three specific aims: Specific Aim 1: To evaluate RBP3 levels in the vitreous and aqueous fluids from non-diabetic controls, people with type 1 and type 2 diabetes of various duration, age, severity of DR and glycemic control. Specific Aim 2: To determine whether elevating the level of RBP3 in the retina or vitreous can decrease retinal or vascular abnormalities induced by diabetes in rodents. Specific Aim 3: To characterize RBP3's signaling and actions in retinal pericyte and endothelial cells.