RNAi therapeutics for Friedreich ataxia

描述(由申请人提供)： Friedreich共济失调(FRDA)是一种常染色体隐性遗传性神经和心脏退行性疾病，目前尚无有效的治疗方法。1996年对疾病基因的鉴定以及随后对编码蛋白Frataxin功能的阐明，为可能的治疗方法打开了大门，包括传统的高通量药物筛选。这项建议描述了一种新的、补充的方法来开发FRDA的治疗学。我们设计了一种方法来构建一个编码随机短发夹环RNA(ShRNAs)的文库。该文库可用于鉴定具有治疗、治疗靶向和/或生物学意义的shRNA序列。这种鉴定是基于功能选择的，通过聚合酶链式反应从存活于特定条件或表现出预定表型的细胞中检索到有效序列。该设计允许对有效序列进行命中优化，并对具有改进效果的序列进行重新选择。利用原代FRDA成纤维细胞，我们开发了基于线粒体功能障碍在FRDA体征和症状中的关键作用以及FRDA细胞对氧化应激的敏感性的筛选和选择分析。通过我们的活/死选择实验，我们可以使用我们的随机shRNA编码库来识别对FRDA细胞有利的shRNA序列。通过我们对线粒体功能的筛选分析，我们可以确认并优先处理这些序列。这项建议的主要目标是确定潜在的shRNA疗法。第二个目标是开始了解我们确定的shRNA的作用机制。其具体目的是：1.鉴定能够在对原代FRDA成纤维细胞致死而对正常对照细胞不致死的条件下存活的shRNA序列。2.优化目标1.3中确定的shRNA序列。3.确认优化后的shRNA并确定其优先顺序，并开始了解其作用机制。这项建议描述了一种利用随机shRNA文库开发治疗Friedreich共济失调的新疗法的方法。这种方法对其他遗传病以及传染病的治疗方法的发展具有潜在的影响，因此与公共卫生高度相关。

DESCRIPTION (provided by applicant): Friedreich ataxia (FRDA) is an autosomal recessive neuro- and cardio-degenerative disorder for which there are currently no established effective treatments. The identification of the disease gene in 1996 and the subsequent elucidation of the function of the encoded protein, frataxin, have opened the door to possible therapeutic approaches, including conventional high-throughput drug screening. This proposal describes a novel, complementary approach to the development of therapeutics for FRDA. We devised a method to construct a library that encodes random, short-hairpin-loop RNAs (shRNAs). This library can be used to identify shRNA sequences of therapeutic, therapeutic-targeting, and/or biological interest. The identification is based on functional selection, with effective sequences retrieved by PCR from cells that survive a particular condition or exhibit a predetermined phenotype. The design allows for hit-optimization of effective sequences, with re-selection for sequences with improved effects. Using primary FRDA fibroblasts, we developed screening and selection assays based on the critical role of mitochondrial dysfunction in the signs and symptoms of FRDA and on the sensitivity of FRDA cells to oxidative stress. With our live/dead selection assays, we can use our random shRNA-encoding library to identify shRNA sequences of benefit to FRDA cells. With our screening assays of mitochondrial function, we can confirm and prioritize these sequences. The primary objective of this proposal is to identify potential shRNA therapeutics. A secondary objective is to begin to understand the mechanisms of action of the shRNAs we identify. The Specific Aims are: 1. To identify shRNA sequences that allow survival under conditions lethal to primary FRDA fibroblasts but non-lethal to normal control cells. 2. To optimize the shRNA sequences identified in Aim 1. 3. To confirm and prioritize optimized shRNAs and begin to understand mechanisms of action. This proposal describes an approach to develop novel therapeutics for Friedreich ataxia using a random shRNA library. This approach has potential implications for the development of therapeutics for other genetic diseases, as well as for infectious diseases, and is therefore highly relevant to public health.