Substrate reduction as a novel therapeutic strategy for Glutaric Aciduria Type 1

项目摘要/摘要 在这个项目中，研究人员建议开发一种治疗1型戊二酸尿症的新方法。 (GA1；MIM 231670)。GA1是赖氨酸、羟赖氨酸和色氨酸的常染色体隐性遗传错误 退化。患者可能会出现巨头畸形，并可能发展为复杂的运动障碍，原因是 急性脑病危象后的纹状体损伤。这种疾病是由戊二酰辅酶A缺乏引起的 脱氢酶(GCDH)，导致神经毒性的戊二酸和3-羟基戊二酸的积累 酸。GA1被认为是一种可治疗的疾病，因此在许多国家包括在新生儿筛查计划中 国家。然而，目前的治疗包括饮食干预、肉碱补充和 紧急护理。这种治疗模式需要护理者和患者付出巨大的努力。一定是 精心维护，但在一些患者中，神经系统疾病仍有可能发展。这些限制 证明需要改进疗效和方便性的新型治疗方案。调查人员 假设通过在赖氨酸降解途径上游使用抑制剂，神经毒素的积累 GA1中的戊二酸和3-羟基戊二酸可以转化为更易耐受的代谢物。一直以来 说明高赖氨酸血症是一种生化表型，无临床意义。它是由基因突变引起的 编码2-氨基己二酸半醛合成酶(AASS)的AASS，是一种位于GCDH上游的酶。 赖氨酸降解途径。调查人员获得的初步数据显示，AASS/AASS基因缺失 限制GA1在细胞和小鼠模型中的代谢物积累。这表明AASS是一种合适的和 治疗GA1的潜在安全靶点。因此，这项提案的总体目标是确定新的 适用于AASS赖氨酸-氧戊二酸还原酶(LOR)结构域的小分子抑制剂 药物化学优化。在目标1中，调查人员将通过以下方式确定酶抑制剂候选者 小分子高通量筛选(HTS)和计算(虚拟)筛选都使用他们最近的 得到了2.2äLor晶体结构。然后，采用基于结构的药物设计、药物化学方法 和共结晶，他们将开发初步的结构-活性关系来验证新的Hit类似物 就像毒品一样的支架。来自HTS和虚拟筛选的所有活跃点击量将在年的AIM 2中进一步评估 以生成具有良好药用化学性质的商业化合物的优先列表。在AIM中 3个经过验证的HIT分子将通过监测建立的GA1细胞模型进行体外测试 抑制LOR和疾病的生物标志物。综合起来，这三个目标不仅会产生很高的收益 LOR的有效HIT抑制剂可以进一步开发用于治疗GA1，但也是重要的额外 赖氨酸降解的生化和生理学数据。

Project Summary / Abstract In this project, the investigators propose to develop a novel treatment option for glutaric aciduria type 1 (GA1; MIM 231670). GA1 is an autosomal recessive inborn error of lysine, hydroxylysine and tryptophan degradation. Patients can present with macrocephaly and may develop a complex movement disorder due to striatal injury after an acute encephalopathic crisis. The disorder is caused by a deficiency of glutaryl-CoA dehydrogenase (GCDH), which leads to the accumulation of neurotoxic glutaric acid and 3-hydroxyglutaric acid. GA1 is considered a treatable disorder and therefore included in newborn screening programs in many countries. However, current treatment consists of dietary intervention, carnitine supplementation, and emergency care. This treatment paradigm requires intense efforts from both caregiver and patient. It must be meticulously maintained, but in some patients neurological disease may still develop. These limitations demonstrate the need for novel therapeutic options with improved efficacy and convenience. The investigators hypothesize that by using inhibitors upstream in the lysine degradation pathway, accumulation of neurotoxic glutaric acid and 3-hydroxyglutaric acid in GA1 can be diverted into more tolerable metabolites. It has been shown that hyperlysinemia is a biochemical phenotype without clinical significance. It is caused by mutations in AASS encoding 2-aminoadipic semialdehyde synthase (AASS), which is an enzyme upstream of GCDH in the lysine degradation pathway. The investigators obtained preliminary data showing that deletion of AASS/Aass limits metabolite accumulation in cell and mouse models for GA1. This suggests that AASS is a suitable and potentially safe target for treatment of GA1. Thus, the overall objective of this proposal is to identify novel small-molecule inhibitors of the lysine-oxoglutarate reductase (LOR) domain of AASS suitable for future medicinal chemistry optimization. In AIM 1, the investigators will identify enzyme inhibitor candidates through both a small molecule high-throughput screen (HTS) and computational (virtual) screening using their recently obtained 2.2Å LOR crystal structure. Then, using structure-based drug design, medicinal chemistry methods and co-crystallization, they will develop preliminary structure-activity relationships to validate new hit analogs as drug-like scaffolds. All active hits from the HTS and virtual screening will be further evaluated in AIM 2 in order to generate a prioritized list of commercial compounds with good medicinal chemistry properties. In AIM 3 selected validated hit molecules will be tested in vitro in cell-based models of GA1 by monitoring established biomarkers for the inhibition of LOR and the disease. Combined, these three aims will yield not only highly validated hit inhibitors of LOR that can be further developed for treatment of GA1, but also important additional data on the biochemistry and physiology of lysine degradation.