Project 2: Therapeutic Gene Editing for Friedreich's Ataxia

项目2（FRDA） 弗里德赖希共济失调（FRDA）是一种常染色体隐性遗传疾病，其特征是进行性共济失调和损害 对神经系统的影响，这通常与肌肉无力，痉挛，心肌病和糖尿病有关 糖尿病。FRDA是由共济失调蛋白（FXN）蛋白水平的缺乏引起的，这种蛋白水平通常来自于GAA三联体 FXN基因内含子1的重复扩增导致转录抑制。FXN GAA的长度- 一般人群中的重复数范围为~5-60，而FRDA患者可能存在66至远超过1200 重复，通常600至900个重复长度。长的GAA重复序列在一些体细胞中经历进行性不稳定性， 主要导致重复扩增并因此导致FXN蛋白丢失的细胞类型。这些组织 在FRDA中受影响的组织包括背根神经节（DRG）、心脏和胰腺。疾病发作 在患者中，与最短FXN等位基因的长度相关，其通常在10-15岁时出现。 年龄，虽然约25%的患者有一个不典型的表现与较晚的疾病发作。 虽然有些症状可以通过物理治疗和手术得到改善，但没有有效的治愈或治疗方法。 用于更广泛的FRDA表型尚未获得批准。FRDA患者的预期寿命通常是 40-50岁。 在这个后续项目中，我们的目标是改善FXN蛋白的表达，以拯救疾病进展， FRDA患者。具体而言，我们的目标是：（1）优化基因组编辑策略以纠正FRDA重复 扩增;（2）优化基因组编辑策略以校正小鼠中的FRDA重复扩增;以及（3）进行 临床前IND使研究能够评估安全性和有效性。我们将与基因编辑核心密切合作， 在FRDA模型系统中开发最新的基础编辑和/或主要编辑技术。我们将与 基因编辑核心，以确保我们的基因组编辑工具最大限度地提高靶向编辑效率， 不希望的基因编辑副产物和脱靶编辑事件，并最大限度地提高与体内 潜在治疗相关性的递送方法。

PROJECT SUMMARY PROJECT 2 (FRDA) Friedreich's Ataxia (FRDA) is an autosomal recessive disorder characterized by progressive ataxia and damage to the nervous system, that is often associated with muscle weakness, spasticity, cardiomyopathy and diabetes mellitus. FRDA is caused by a deficiency in frataxin (FXN) protein levels that usually arises from a GAA-triplet repeat expansion in intron 1 of the FXN gene which results in transcriptional repression. The length of FXN GAA- repeats in the general population ranges from ~5-60, while FRDA patients may present with 66 to well over 1200 repeats, typically 600 to 900 repeats long. Long GAA-repeats undergo progressive instability in some somatic cell types that predominantly results in repeat expansion and consequently loss of FXN protein. The tissues that are affected in FRDA include the dorsal root ganglia (DRGs), the heart, and the pancreas. The onset of disease in patients is anticorrelated with the length of the shortest FXN allele, which typically presents at 10-15 years of age, though approximately 25% of patients have an atypical presentation with later disease onset. Although some symptoms can be ameliorated by physical therapy and surgery, no effective cure or treatment for the broader FRDA phenotype has yet been approved. The life expectancy for patients with FRDA is typically 40-50 years of age. In this follower project, we aim to improve FXN protein expression to enable rescue of disease progression in FRDA patients. Specifically, we aim to: (1) Optimize genome editing strategies to correct FRDA repeat expansion; (2) optimize genome editing strategies to correct FRDA repeat expansion in mice; and (3) perform pre-clincial IND enabling studies to assess safet and efficacy. We will work closely with the Gene Editing Core to develop the latest base editing and/or prime editing technologies in FRDA model systems. We will iterate with the Gene Editing Core to ensure that our genome editing tools maximize on-target editing efficiencies, minimize undesirable gene editing byproducts and off-target editing events, and maximize compatibility with in vivo delivery methods of potential therapeutic relevance.