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

 描述（由申请人提供）：糖尿病视网膜病变（DR）是发达国家视力丧失的主要原因，影响90%的1型糖尿病患者（T1 DM），病程至少15年。激光光凝和抗VEGF药物等治疗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，基于高血糖症机制的早期DR临床治疗尚未成功。由于Joslin 50年奖章获得者研究队列（n>900）的流行病学观察结果，一组患有50年或50年以上T1 DM的患者，尽管早期血糖控制工具有限，但未发生重度DR（患病率35%），因此我们专注于寻找内源性视网膜保护因子。使用视网膜和玻璃体的蛋白质组学分析，发现即使在存在高血糖的情况下，与PDR患者相比，患有非轻度DR的Medalists中的类维生素A结合蛋白-3（RBP 3）升高。初步数据显示，与活动性或静止性PDR相比，非轻度DR玻璃体中RBP 3升高的模式在T1 D和T2 D患者中是一致的。纯化的RBP 3抑制高血糖和VEGF对视网膜内皮细胞和周细胞的作用。有趣的是，纯化的RBP 3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度表达RBP 3可防止糖尿病刘易斯大鼠毛细血管通透性和VEGF表达的增加、ERG和OCT测量的神经视网膜功能障碍、无细胞毛细血管的形成和周细胞凋亡，所有这些都表明RBP 3蛋白的保护能力。这些研究表明，RBP 3除了在光感受器和视网膜色素上皮细胞之间转运类维生素A外，还具有其他功能。为了证实RBP 3可以在视网膜中对高血糖的不良影响具有保护性和新颖的作用，我们提出了三个具体目标：具体目标1：评估非糖尿病对照、1型糖尿病患者的玻璃体和房水中的RBP 3水平。2型糖尿病的持续时间、年龄、DR的严重程度和血糖控制。具体目标二：确定视网膜或玻璃体中RBP 3水平升高是否可以减少啮齿动物中糖尿病诱导的视网膜或血管异常。具体目标3：表征RBP 3在视网膜周细胞和内皮细胞中的信号传导和作用。

 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.