MRC Human Genetics Unit, MRC Institute of Genetics & & Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, United Kingdom.
Invest Ophthalmol Vis Sci. 2013 May 1;54(5):3569-78. doi: 10.1167/iovs.12-11125.
A mouse mutant identified during a recessive N-ethyl-N-nitrosourea (ENU) mutagenesis screen exhibited ocular hemorrhaging resulting in a blood-filled orbit, and hence was named "redeye." We aimed to identify the causal mutation in redeye, and evaluate it as a model for diabetic retinopathy (DR).
The causative gene mutation in redeye was identified by haplotype mapping followed by exome sequencing. Glucose tolerance tests, detailed histologic and immunofluorescence analyses, and vascular permeability assays were performed to determine the affect of redeye on glucose metabolism, pericyte recruitment, and the development of the retinal vasculature and blood-retinal barrier (BRB).
A mutation was identified in the Pdgfrb gene at position +2 of intron 6. We show that this change causes partial loss of normal splicing resulting in a frameshift and premature termination, and, therefore, a substantial reduction in normal Pdgfrb transcript. The animals exhibit defective pericyte recruitment restricted to the central nervous system (CNS) causing basement membrane and vascular patterning defects, impaired vascular permeability, and aberrant BRB development, resulting in vascular leakage and retinal ganglion cell apoptosis. Despite exhibiting classic features of diabetic retinopathy, redeye glucose tolerance is normal.
The Pdgfrb(redeye/redeye) mice exhibit all of the features of nonproliferative DR, including retinal neurodegeneration. In addition, the perinatal onset of the CNS-specific vascular phenotype negates the need to age animals or manage diabetic complications in other organs. Therefore, they are a more useful model for diseases involving pericyte deficiencies, such as DR, than those currently being used.
在隐性 N-乙基-N-亚硝脲（ENU）诱变筛选中发现的一种小鼠突变体表现出眼球出血导致充满血液的眼眶，因此被命名为“红眼”。我们旨在确定红眼的致病突变，并将其评估为糖尿病视网膜病变（DR）的模型。
通过单倍型图谱绘制和外显子组测序鉴定红眼的致病基因突变。进行葡萄糖耐量试验、详细的组织学和免疫荧光分析以及血管通透性测定，以确定红眼对葡萄糖代谢、周细胞募集以及视网膜血管和血视网膜屏障（BRB）发育的影响。
在第 6 号内含子的+2 位置鉴定出 Pdgfrb 基因的突变。我们表明，这种变化导致正常剪接的部分缺失，导致移码和过早终止，因此正常 Pdgfrb 转录本大量减少。这些动物表现出周细胞募集缺陷，仅限于中枢神经系统（CNS），导致基底膜和血管图案缺陷、血管通透性受损以及异常的 BRB 发育，导致血管渗漏和视网膜神经节细胞凋亡。尽管表现出糖尿病视网膜病变的典型特征，但红眼的葡萄糖耐量正常。
Pdgfrb(redeye/redeye) 小鼠表现出非增生性 DR 的所有特征，包括视网膜神经退行性变。此外，CNS 特异性血管表型的围产期发作消除了对动物衰老或管理其他器官中糖尿病并发症的需要。因此，与目前使用的模型相比，它们是涉及周细胞缺陷的疾病（如 DR）的更有用模型。
