Pediatric Heart Disease: Getting from Mutations to Therapeutics

儿科心血管疾病，包括先天性心脏缺陷（CHD）和心肌和 传导系统疾病由于心脏合并症和过早死亡而仍然具有高度挑战性。 由于大多数这些疾病是遗传性的，过去30年的努力集中在确定其病因上。 突变特别是对于孟德尔性状，如努南综合征和相关疾病（ ），这是非常成功的。更新的基因组技术加速了基因发现 用于儿科心血管疾病，包括遗传复杂的疾病。这些基因发现是 通过更准确的诊断、更好的诊断和完善的临床试验设计来改善护理。 除了罕见的例外，还没有出现的是基于新的治疗方法的发展。 这些基因的发现使人们对疾病发病机制的理解成为可能。寻找治疗方法 儿科心血管疾病将是具有挑战性的，因为生物靶点通常是细胞的中心， 稳态（例如，RAS/MAP激酶信号传导），因此不能长时间完全抑制， 带来的副作用会超过它们的好处。对于这个R35机制，我和我杰出的合作伙伴- 具有相关专业知识的研究人员打算使用药物开发管道来解决这一差距， 通过高通量筛选克服果蝇疾病模型中的蛹致死性， 使用96孔板和机器人技术，覆盖可药用空间的化学品库（n= 14，400）。筛查 整个动物是不可知的，并且具有提供同时读出的假定优势 有效性和毒性。我们提供的初步数据表明，我们已经实现了这一点， 努南综合征伴肥大性心肌病的RAF 1突变模型。果蝇的后续步骤 包括在小瓶中确认初始命中，确定对成蝇表型如粗眼的功效， 异位翼静脉和心脏肥大候选化合物的备份库，通常为60-80 化学邻居，将被淘汰的最理想的药物性状，然后在苍蝇模型筛选。 使用一组确定的果蝇缺陷系，将建立靶标和抗靶标，以使得能够进一步进行基因治疗。 一轮轮的理性药理学。ADME研究将用于降低药物间相互作用的可能性。在 与此同时，我们将利用果蝇模型库筛选，对FDA批准的药物进行再利用， 系统药物基因组学然后将针对人类的表型测试主要化合物和药物。 具有致病突变的诱导多能干细胞系用于功效。最有前途的药物 然后将在现有的小鼠模型中进行测试（例如，Raf 1突变小鼠中的HCM）。 总的来说，所提出的方法将显著推进新疗法的鉴定， 儿科心血管疾病，从RASopathies开始，后来用于其他特征。如果健壮，这将 为NHLBI感兴趣的其他遗传性状提供了一个范例。

Pediatric cardiovascular disorders, which comprise congenital heart defects (CHD) and myocardial and conduction system diseases, remain highly challenging due to cardiac co-morbidities and premature mortality. As most of these disorders are genetic, efforts over the past 30 years have focused on identifying their causal mutations. Particularly for Mendelian traits such as Noonan syndrome and related disorders (the RASopathies), this has been highly successful. Newer genomic technologies have accelerated gene discovery for pediatric cardiovascular disorders, including genetically complex ones. These genetic discoveries are improving care through more accurate diagnosis, better prognostication, and refinement of clinical trial design. What has not occurred with rare exception is the development of novel therapies based on the new understanding of disease pathogenesis enabled by these gene discoveries. Finding therapies for pediatric cardiovascular disorders will be challenging because the biological targets are generally central to cell homeostasis (e.g., RAS/MAP kinase signaling) so cannot be completely inhibited for long periods without incurring side effects that would outweigh their benefits. For this R35 mechanism, I and my outstanding co- investigators with relevant expertise intend to address this gap using a drug development pipeline that begins with high-throughput screening to overcome pupal lethality in Drosophila melanogaster models of disease with a chemical library that covers druggable space (n=14,400) using 96-well plates and robotics. Screening in whole animals is performed agnostically and has the putative advantage of providing a simultaneous read out of efficacy and toxicity. We provide preliminary data showing that we have already achieved this using a fly RAF1 mutant model of Noonan syndrome with hypertrophic cardiomyopathy. Subsequent steps with fruit flies include confirmation of initial hits in vials, determining efficacy against adult fly phenotypes such as rough eye, ectopic wing veins and heart hypertrophy. Back-up libraries for the candidate compounds, typically 60-80 chemical neighbors, will be culled for ones with most desirable drug traits and then screened in the fly models. Using a defined set of fruit fly deficiency lines, targets and anti-targets will be established to enable further rounds of rational pharmacology. ADME studies will be used to reduce potential for drug-drug interactions. In parallel, we will pursue repurposing of FDA-approved drugs using library screening with fruit fly models and systems pharmacogenomics. Leading compounds and drugs will then be tested against phenotypes in human induced pluripotent stem cell lines with the disease-causing mutation for efficacy. The most promising drugs will then be tested in existing mouse models (e.g., HCM in Raf1 mutant mice) using appropriate endpoints. Taken as a whole, the approach proposed will significantly advance the identification of novel therapeutics for pediatric cardiovascular diseases, starting with the RASopathies and later for other traits. If robust, this will provide a paradigm that can be adopted for other genetic traits of interest to the NHLBI.