Leber Congenital Amaurosis 8 models and pathogenic mechanisms

Leber先天性黑蒙8种模型及发病机制

• 批准号: 10254946
• 负责人: Seo-Hee Cho
• 金额: $ 39.44万
• 依托单位: THOMAS JEFFERSON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-08 至 2023-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10254946
• 关键词: Leber; Congenital; Amaurosis; models; pathogenic

Project Summary Leber congenital amaurosis 8 (LCA8) is the most severe, non-treatable, early-onset (usually at birth) blinding disease that is caused by recessive mutations in Crumbs homolog 1 (Crb1) gene. About 20% of children attending schools for the blind around world are affected by LCA. Development of effective, mechanism-based therapies require models that replicate human LCA8 pathology. Current mouse models have limitations in reproducing human phenotypes partly due to partial gene ablation in ocular tissues, thus pathogenic mechanism studies at the cellular and molecular levels are inadequate. The newly-generated, improved mouse model using conditional ablation of Crb1 and its paralog, Crb2, exhibits main features of LCA8 including thick retina, indistinct retinal lamination, defects in the retinal pigment epithelium, and most importantly, the early- onset visual loss at the eye opening stage. Intriguingly, our data also indicate that retinal pathology starts in the retinal progenitor cells (RPCs), unlike most other types of LCA. Mutant RPCs undergo defective interkinetic nuclear migration that may alter cellular processes involved in cell proliferation, growth, apico-basal polarity, and actomyosin cytoskeleton regulation. Additionally, we found that several signaling cascades were severely altered; decreased Yap signaling essential for the proliferation of the RPCs and cell survival; increased mTOR pathway implicated in cell growth and proliferation; over-activated RhoA-ROCK signaling regulating cytoskeleton dynamics by controlling actomyosin assembly. Therefore, we hypothesize that perturbed Crb1/Crb2 downstream signaling activities play crucial roles in the initial pathogenesis of LCA8 in the RPCs. To test this, we will first fully assess the development of LCA8 pathology using histological, immunofluorescence assays along with a non-invasive, longitudinal imaging for quantifying retinal lesions. Second, we will delineate RPC-specific, cellular and molecular mechanisms underlying LCA8 pathogenesis. Third, we will define signaling pathway-dependent contributions to LCA8 pathology by genetic and pharmacological approaches.

项目摘要 Leber先天性Amaurosis 8（LCA8）是最严重，最不可治疗的早期发作（通常在出生时） 由Crumbs同源物1（CRB1）基因中隐性突变引起的疾病。约20％的孩子 在世界各地的盲人上学受到LCA的影响。开发有效的，基于机制的 疗法需要复制人LCA8病理学的模型。当前的鼠标模型在 重现人类表型部分是由于眼组织中部分基因消融，因此致病 细胞和分子水平的机理研究不足。新生成的，改进的鼠标 使用CRB1的条件消融及其旁系同源物CRB2的模型展示了LCA8的主要特征 视网膜，视网膜层压不清，视网膜色素上皮的缺陷，最重要的是早期 开眼界的视觉丧失。有趣的是，我们的数据还表明视网膜病理始于 与大多数其他类型的LCA不同，视网膜祖细胞（RPC）。突变的RPC发生有缺陷的互动性 核迁移可能会改变参与细胞增殖，生长，apico-basal极性的细胞过程， 和肌动球蛋白细胞骨架调节。此外，我们发现几个信号级联严重 改变； YAP信号传导减少对于RPC和细胞存活至关重要的降低；增加mtor 涉及细胞生长和增殖的途径；过度激活的Rhoa-Rock信号调节 通过控制肌动蛋白组装来控制细胞骨架动力学。因此，我们假设这种干扰 CRB1/CRB2下游信号传导活动在RPC中LCA8的初始发病机理中起着至关重要的作用。 为了测试这一点，我们将首先使用组织学， 免疫荧光测定以及无创纵向成像，用于量化视网膜病变。 其次，我们将描绘LCA8发病机理的RPC特异性，细胞和分子机制。 第三，我们将通过遗传和 药理方法。