Pathogenesis of age-related Fuchs Endothelial Corneal Dystrophy

年龄相关性福克斯内皮性角膜营养不良的发病机制

基本信息

批准号：
9055004
负责人：
MICHAEL P. FAUTSCH
金额：
$ 51.97万
依托单位：
MAYO CLINIC ROCHESTER
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-01-01 至 2019-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9055004
关键词：
Allogenic Antithymoglobulin BHLH Protein Biological Models Blindness Cataract Extraction Cell Culture Techniques Cell Nucleus Cell physiology Cells Cerebellar Ataxia Chromosomes, Human, Pair 18 Clinical Cornea Corneal Endothelium Corneal edema DNA Data Degenerative Disorder Deposition Development Disease Disease Progression Endothelial Cells Event Extracellular Matrix Eye diseases Fragile X Syndrome Fuchs&apos Endothelial Dystrophy Future Gene Expression Genes Genetic Genetic Transcription Genomics Homeostasis Huntington Disease Individual Introns Keratoplasty Knowledge Lasers Left Length Light Link Mediating Medical Mesenchymal Messenger RNA Modeling Molecular Myotonic Dystrophy Operative Surgical Procedures Oxidative Stress Pathogenesis Patients Peptides Phenotype Physiological Platelet Factor 4 Positioning Attribute Postoperative Period Protein Family Protein Kinase Proteins Publishing RNA RNA Splicing Research Risk Role Staging Stress Syndrome Testing Tissues Transcript Translations Transplantation Trinucleotide Repeat Expansion Untranslated RNA Work age related base endoplasmic reticulum stress genetic variant member monolayer nervous system disorder novel novel therapeutic intervention polyglutamine protein aggregate protein function public health relevance research study response stressor targeted treatment therapeutic development transcription factor

项目摘要

DESCRIPTION (provided by applicant): This is a multiple PI R01 application to test the hypothesis that trinucleotide repeat expansion (TNR) is a causal event in the pathogenesis of Fuchs endothelial corneal dystrophy (FECD). FECD is a common, degenerative disease of the corneal endothelial cell monolayer. Unfortunately, there are no medical therapies to halt disease progression, and the pathogenesis is not well understood. As a result, surgical transplantation of the cornea is the only viable treatment. In fact, end-stage FECD is the most common cause of allogeneic corneal transplantation in the U.S., responsible for greater than 14,000 grafts annually. Recently, we have identified a CTG TNR expansion sequence within the third intron of the transcription factor 4 (TCF4) gene that associates with 79% of FECD cases. To date, this is the most predictive genetic anomaly identified for FECD. In FECD, CTG TNR expansions range from 50-2000 repeats, which are significantly higher than non-FECD patients who typically have 12-18 CTG repeats. How this TCF4 CTG TNR expansion region promotes the FECD phenotype is not clear. Similar expansion of unstable TNR sequences have been identified as the causative pathogenic mechanism in several rare and debilitating neurologic disorders, such as spin cerebellar ataxias, Huntington disease, fragile X syndrome and myotonic dystrophy, type 1. These TNR expansion regions are thought to interfere with normal protein function, expression of the TNR containing gene, and/or RNA splicing in cis and trans. In addition, translation of toxic Repeat-Associated Non-ATG (RAN) translation products from the sense and antisense transcripts of the TNR expansion sequences have also been identified as a contributing factor towards disease progression. Our preliminary studies suggest similar events are occurring in FECD cells. According to our data, transcripts from the TCF4 CTG TNR expansion region are retained in the nucleus and form ribonuclear inclusions called RNA foci in FECD tissue and primary FECD monolayer cells. These RNA foci sequester the splicing factor MBNL1, leading to altered splicing of numerous transcripts. We also have evidence for RAN translation of TCF4 CTG TNR expansion RNA, producing small homopolymeric protein aggregates in corneal endothelial cells of FECD patients. Our central hypothesis is that RNA foci and RAN translation protein products arising from the TCF4 CTG TNR expansion region causes FECD by altering gene expression and disrupting critical cell functions. It is our premise that stress factors (e.g. oxidative stress) promote instability in the TCF4 CTG TNR expansion sequence resulting in the formation of CUG repeat containing RNA foci and accumulation of RAN translation products. The presence of these products leads to differential mRNA splicing and altered expression of critical genes, stimulating ER stress-mediated activation of unfolded protein response (UPR), endothelial to mesenchymal transformation (EMT) and disordered extracellular matrix (ECM) deposition. We will test our hypothesis with two specific aims - 1) Characterize the molecular anomalies associated with TCF4 CTG TNR expansion in FECD; 2) Determine the role of TCF4 CTG TNR expansion in pathogenesis of FECD. Completion of these two specific aims will provide a mechanistic understanding of how TCF4 CTG TNR expansion is involved in FECD pathogenesis. Understanding the molecular events underlying the pathogenesis of FECD will be essential for future development of targeted therapeutic strategies for management of FECD.

描述（由申请人提供）：这是一个多 PI R01 申请，用于测试三核苷酸重复扩增 (TNR) 是 Fuchs 内皮性角膜营养不良 (FECD) 发病机制中的因果事件的假设，FECD 是一种常见的退行性疾病。不幸的是，没有药物可以阻止疾病的进展，并且其发病机制尚不清楚，因此，角膜手术移植是唯一的选择。事实上，终末期 FECD 是美国同种异体角膜移植的最常见原因，每年有超过 14,000 例移植手术，最近，我们在转录因子的第三个内含子内发现了 CTG TNR 扩展序列。 4 (TCF4) 基因与 79% 的 FECD 病例相关，迄今为止，这是在 FECD、CTG 中发现的最具预测性的基因异常。 TNR 扩增范围为 50-2000 次重复，明显高于通常具有 12-18 个 CTG 重复的非 FECD 患者。这种 TCF4 CTG TNR 扩增区域如何促进 FECD 表型尚不清楚。已被确定为几种罕见且使人衰弱的神经系统疾病的致病机制，例如旋转小脑性共济失调、亨廷顿病、脆性 X 综合征和强直性肌强直营养不良，1 型。这些 TNR 扩展区域被认为会干扰正常的蛋白质功能、含有 TNR 的基因的表达和/或 RNA 顺式和反式剪接。此外，还会干扰有毒物质的翻译。根据我们的数据，来自 TNR 扩增序列的有义和反义转录本的重复相关非 ATG (RAN) 翻译产物也被确定为疾病进展的促成因素。，来自 TCF4 CTG TNR 扩展区域的转录物保留在细胞核中，并在 FECD 组织和原代 FECD 单层细胞中形成称为 RNA 灶的核糖核包涵体。这些 RNA 灶隔离剪接因子。 MBNL1，导致大量转录物的剪接发生改变，我们也有证据表明 TCF4 CTG TNR 扩展 RNA 的 RAN 翻译，在 FECD 患者的角膜内皮细胞中产生小均聚物蛋白聚集体。我们的中心假设是 RNA 灶和 RAN 翻译蛋白产物的产生。 TCF4 CTG TNR 扩展区域通过改变基因表达和破坏关键细胞功能来引起 FECD。氧化应激）会促进 TCF4 CTG TNR 扩展序列的不稳定，导致包含 RNA 焦点的 CUG 重复序列的形成和 RAN 翻译产物的积累。这些产物的存在导致差异 mRNA 剪接和关键基因的表达改变，刺激 ER 应激。介导的未折叠蛋白反应（UPR）激活、内皮间质转化（EMT）和无序细胞外基质（ECM）沉积我们将通过两个具体目标来检验我们的假设 - 1）表征。与 FECD 中 TCF4 CTG TNR 扩增相关的分子异常；2) 确定 TCF4 CTG TNR 扩增在 FECD 发病机制中的作用完成这两个具体目标将提供对 TCF4 CTG TNR 扩增如何参与 FECD 发病机制的机制理解。 FECD 发病机制背后的分子事件对于未来制定 FECD 靶向治疗策略至关重要。