Mechanism of APBB2 contributions to glaucoma

摘要 青光眼是一组以视网膜神经节细胞缺失为特征的与年龄相关的神经退行性疾病 和他们的轴突。由于视网膜节细胞是有丝分裂后神经元，它们的丧失是永久性的，并导致逐渐的 衰退导致不可逆转的失明。不幸的是，青光眼的表现损害了美国 更广泛的社会--它对某些种族群体的影响不成比例。青光眼是一个更严重的问题 在非裔美国人而非高加索人中。尽管社会经济因素往往是造成这种差距的原因， 很大一部分是生物学上的，是由种族群体之间的基因组差异驱动的。最近的一项突破 指出APBB2是非裔美国人青光眼的中心。大型全基因组关联研究(GWAS) 在APBB2(Rs59892895)上发现了具有全基因组意义的单核苷酸多态(P=2x10-8； 优势比=1.33)，并在其他队列中成功复制了这一发现。在APBB2中发现了一个变体 基因是非洲人后裔青光眼的重要原因。ABPP2编码一个细胞质适配器 具有多个蛋白质-蛋白质相互作用结构域的蛋白质。值得注意的是，高危等位基因存在于 大约21%的非裔美国人，显然不是高加索人。我们的团队为 APBB2作为一种对非裔美国人青光眼重要的基因的发现，另外还显示了 在我们的初步数据中，我们提出了一个假设，即APBB2的过度表达是导致疾病的原因 机制。为了测试这一新假设，我们最近生成了一个小鼠模型， 高表达Apbb2的纯C57BL/6J遗传背景。这种毒株是由加州大学制造的 爱荷华州基因组编辑设施，并以全长小鼠Apbb2(转录变体1)为特色，受 无处不在的启动子(CAG)，并包括连接到N-末端的6His/3X旗帜(缩写为B6- TG(Apbb2)。该方案的实验利用该新菌株作为中心资源来完成 重要的，但有些高风险，通过操纵测试Apbb2的过度表达促进青光眼。在……里面 具体目标1，我们建议测试Apbb2随时间的解剖和生理后果 在小鼠体内过度表达。这一目标还将完成对B6-Tg(Apbb2)菌株的彻底表征。 特定目标2将从分子角度研究APBB2，识别视网膜APBB2结合伙伴， 将指导未来机械化和候选人驱动的基因实验。

Abstract Glaucoma is a group of age-related neurodegenerative diseases characterized by loss of retinal ganglion cells and their axons. Because RGCs are post-mitotic neurons, their loss is permanent and causes a gradual decline leading toward irreversible blindness. Unfortunately, glaucoma manifests in a way that damages US society more broadly—it disproportionately affects certain racial groups. Glaucoma is a worse problem amongst African Americans than Caucasians. Though socioeconomic factors often contribute to this disparity, a large part is biological and driven by genomic differences between racial groups. A recent breakthrough points to APBB2 as central to glaucoma in African Americans. A large genome-wide association study (GWAS) has found a single nucleotide polymorphism in APBB2 (rs59892895) with genome-wide significance (P=2x10-8; Odds ratio=1.33), and successfully replicated the finding in additional cohorts. identified a variant in the APBB2 gene as an important cause of glaucoma in people of African descent. ABPP2 encodes a cytoplasmic adaptor protein with multiple protein-protein interaction domains. Remarkably, the high-risk allele is present in approximately 21% of African Americans and apparently absent from Caucasians. Our team has contributed to this discovery of APBB2 as a gene of importance to glaucoma in African Americans, and as additionally shown in our Preliminary Data, have developed a hypothesis that overexpression of APBB2 is the disease-causing mechanism. To test this new hypothesis, we recently generated and now have in hand, a mouse model on a pure C57BL/6J genetic background that is overexpressing Apbb2. The strain was created by the University of Iowa Genome Editing Facility and features a full-length mouse Apbb2 (transcript variant 1) under control of a ubiquitous promotor (CAG) and includes a 6His/3XFlag attached to the N-terminus (abbreviated as B6- Tg(Apbb2). The experiments of this proposal utilize this new strain as a central resource to complete the important, but somewhat high risk, test via manipulation that over-expression of Apbb2 promotes glaucoma. In Specific Aim 1, we propose to test the anatomical and physiological consequences over time of Apbb2 overexpression in mice. This Aim will also complete a thorough characterization of the B6-Tg(Apbb2) strain. Specific Aim 2 will study APBB2 from a molecular perspective, identifying retinal APBB2 binding partners that will guide future mechanistic and candidate-driven genetic experiments.