Identification of therapeutic compounds for Charcot-Marie-Tooth disease type 1E/1

描述（由申请人提供）：腓骨肌萎缩症是人类最常见的遗传性神经病变。除了姑息性手术和物理康复之外，没有任何形式的CMT有效的治疗方法。神经病变可显著降低患者的生活质量。我们共同发现了CMT1A潜在的前所未有的大DNA重复，这是一种常染色体显性亚型，在60%的CMT患者中可见。外周髓鞘蛋白PMP22的过量产生是CMT1A的基础，而约5%的CMT1患者被归类为CMT1E， PMP22存在显性点突变。对过度表达Pmp22或携带Pmp22点突变的小鼠的检查表明，过量或缺陷的Pmp22积聚在细胞质或核周聚集体中。这被认为减少了雪旺细胞膜内PMP22蛋白的数量，并可能导致髓鞘异常表型。此外，有证据表明Pmp22的点突变降低了野生型蛋白运输到细胞表面的效率。我们假设，一种小分子可以刺激聚集体的降解或分解，并可能允许PMP22的适当折叠/加工，这可能具有治疗益处。为了验证这一假设，我们开发了一种高通量筛选（HTS）试验，以鉴定减少携带点突变的PMP22聚集的小分子。从最初筛选的30,000种化合物中获得的结果已经确定了30种化合物，这些化合物可以减少70%的聚集体形成。为了鉴定一组不同的先导化合物，这些先导化合物可以作为CMT1E/1A的治疗方案，我们提出以下目标：(1)检查我们最初筛选确定的每种支架在重新合成后最活跃的化合物，对聚集体的影响，它们的作用位点，PMP22到膜的运输和毒性，以描绘最有希望的化合物。(2)对hit化合物进行药物化学驱动优化，在一级和二级分析中测试新的类似物，建立构效关系（SAR）。目的是鉴定具有适当效力，低毒性，药物样性质和药代动力学的类似物，适用于体内评价

DESCRIPTION (provided by applicant): Charcot-Marie-Tooth disease is the most common inherited neuropathy in humans. There are no effective treatments for any form of CMT other than palliative surgery and physical rehabilitation. The neuropathy can significantly lower the quality of life in patients. We co-discovered the unprecedented large DNA duplication underlying CMT1A, an autosomal dominant subtype seen in ~60% of all CMT patients. Overproduction of the peripheral myelin protein, PMP22 underlies CMT1A while ~5% of CMT1 patients classified as having CMT1E bear a dominant point mutation in PMP22. Examination of mice over-expressing Pmp22 or bearing a Pmp22 point mutation have shown that excessive or defective Pmp22 accumulates in cytosolic or perinuclear aggregates. This is thought to decrease the amount of PMP22 protein within the Schwann cell membrane and likely contribute to the dysmyelinating phenotype. Additionally, there is evidence that point mutations in Pmp22 lower the efficiency by which the wild-type protein traffics to the cell surface. We hypothesize that a small molecule that stimulates degradation or resolution of the aggregates and possibly allows proper folding/processing of the PMP22 could have therapeutic benefit. To test this hypothesis, we have developed a high-throughput screening (HTS) assay to identify small-molecules that reduce aggregation of PMP22 bearing a point mutation. Results obtained from an initial screen of 30,000 compounds has identified 30 compounds that that reduce aggregate formation by >70%. Towards identification of a diverse set of lead compounds that can be developed as therapeutic regimens for CMT1E/1A, we propose the following Aims: (1) Examine the most active compounds after resynthesis from each of the scaffolds identified by our initial screen the effect on aggregates, their site of action, trafficking of PMP22 to the membrane and toxicity to delineate the most promising compounds. (2) Conduct medicinal chemistry driven optimization of the hit compounds and test new analogs in the primary and secondary assays and build structure-activity relationships (SAR). The goal is to identify analogs with appropriate potency, low toxicity, drug-like properties and pharmacokinetics that are suitable for in vivo evaluation in mouse models of CMT1E and CMT1A. The deliverables from Aims 1 and 2 are at least two compounds with efficacy at levels <1uM and toxicity at levels >50uM that would be ready for testing in mouse models of CMT1E and CMT1A.