Optimizing Small Molecule Read-Through Compounds for Treating AtaxiaTelangiectasia

项目摘要 共济失调-毛细血管扩张症（A-T）是一种罕见的（每10万人中约1人），但灾难性和致命的疾病， 在10至30岁之间运动功能逐渐丧失和死亡。在大约三分之一的A-T 例，原因是ATM（共济失调-毛细血管扩张突变）基因中的无义突变，该基因编码 提前终止密码子（PTC）。没有有效的治疗方法。然而，我们的团队一直在 开发和测试一系列化合物，有效地通读转录mRNA中的PTC。 已发表和未发表的研究证明了这些“SMRT”化合物的能力（对于小分子 ReadThrough）以通读PTC并在体内和离体恢复功能性ATM蛋白的翻译 实验有希望的治疗结果加强了进一步开发SMRT化合物的理由 在Duchenne肌营养不良症和遗传性肺动脉高压的小鼠模型中， 合作者然而，这些模型的成功并不能确保多系统、神经系统和神经系统的成功。 A-T这样的疾病，部分原因是A-T独特地需要化合物穿过血脑屏障， 足够的数量。我们在临床前研究中取得了相当大的进展。我们提供的数据表明， SMRT化合物引发穿透大脑的全长功能蛋白的合成。我们最近还 解决了A-T研究领域的一个主要障碍：缺乏忠实反映临床疾病的动物模型。 在NINDS支持的研究中，我们使用了双重打击策略来产生一种具有临床意义的小鼠。 ATM基因中的相关PTC和称为aprataxin（Aptx）的相关DNA修复基因的敲除。 该小鼠模型的表征，包括作为A-T标志的深刻的进行性共济失调， 完成.现在，我们进入下一个逻辑阶段：使用合理化和全面的方法来优化 我们的首选SMRT化合物在AIM 1中，我们将开发和验证一种新的 专为评价10种最常见的A-T无义性效价而设计的效价测定 突变。在AIM 2中，我们将开发和验证一种旨在确认ATM在人类细胞中功能的测定方法 利用我们独特的A-T患者衍生细胞系库。最后，在AIM 3中，这些测定（沿着 与那些已经在我们的实验室标准，以评估溶解度，蛋白质结合，血脑屏障通透性， 毒性）将用于进行药物化学优化活动，以生成一小部分 候选化合物的性质，最大限度地提高他们的成功机会，在后续的疗效研究，在我们的 新的A-T小鼠模型。我们的工作代表了第一个真实的希望，为儿童遭受的破坏性影响。

PROJECT SUMMARY Ataxia-Telangiectasia (A-T) is a rare (~ 1 in every 100,000) but catastrophic and deadly disease that causes progressive loss of motor function and death between the ages of 10 and 30 years. In about one-third of A-T cases, the cause is a nonsense mutation in the ATM (Ataxia-Telangiectasia mutated) gene that encodes a premature termination codon (PTC). No effective treatments are available. However, our group has been developing and testing a series of compounds that effectively readthrough PTCs in the transcribed mRNA. Published and unpublished studies demonstrate the capability of these “SMRT” compounds (for Small Molecule ReadThrough) to readthrough PTCs and restore translation of functional ATM protein in in vivo and ex vivo experiments. The rationale to further develop SMRT compounds is strengthened by promising therapeutic results in mouse models for Duchenne muscular dystrophy and hereditary pulmonary arterial hypertension by our collaborators. However, success in these models does not ensure success in a multisystem, neurological disorder like A-T, in part because A-T uniquely requires the compound to cross the blood-brain barrier in adequate amounts. We have made considerable progress in our preclinical studies. We present data indicating that SMRT compounds elicit synthesis of full-length functional protein that penetrates the brain. We also recently solved a major hurdle in the field of A-T research: lack of an animal model that faithfully reflects clinical disease. In NINDS-supported studies, we used a double hit strategy to generate a mouse harboring both a clinically relevant PTC in the ATM gene and a knockout of a related DNA repair gene called aprataxin (Aptx). Characterization of this mouse model, including the profound, progressive ataxia that is a hallmark of A-T is complete. Now, we move to next logical phase: to use a rationalized and comprehensive approach to optimize our top candidate SMRT compound via medicinal chemistry. In AIM 1 we will develop and validate a novel potency assay specifically designed to evaluate potency across the 10 most common A-T causing nonsense mutations. In AIM 2 we will develop and validate an assay designed to confirm ATM function in human cells taking advantage of our unique repository of A-T patient derived cell lines. Finally, in AIM 3, these assays (along with those already standard in our labs to assess solubility, protein binding, blood brain barrier permeability, and toxicity) will be utilized to conduct a medicinal chemistry optimization campaign to generate a small set of candidate compounds with properties that maximize their chances of success in follow-on efficacy studies in our new A-T mouse model. Our work represents the first real hope for kids suffering from A-T's devastating effects.