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

项目总结/摘要 在这个项目中，研究人员提出开发一种新的治疗选择谷氨酸尿症1型 (GA1; MIM 231670）。GA 1是赖氨酸、羟赖氨酸和色氨酸的常染色体隐性遗传病 降解患者可能出现大头畸形，并可能因以下原因出现复杂的运动障碍 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），导致神经毒性谷氨酸和3-羟基谷氨酸的积累 酸GA 1被认为是一种可治疗的疾病，因此在许多国家被纳入新生儿筛查计划。 国家然而，目前的治疗包括饮食干预，肉毒碱补充， 紧急护理。这种治疗模式需要护理人员和患者双方的强烈努力。必须 这些药物可以得到精心维护，但在某些患者中，神经系统疾病仍可能发展。这些限制 证明了对具有改善的功效和便利性的新型治疗选择的需要。调查人员 假设通过在赖氨酸降解途径的上游使用抑制剂， GA 1中的谷氨酸和3-羟基谷氨酸可转化为更耐受的代谢物。已经 表明高赖氨酸血症是一种无临床意义的生化表型。它是由突变引起的， AASS编码2-氨基己二酸半醛合酶（AASS），其是在大肠杆菌中GCDH上游的酶。 赖氨酸降解途径研究人员获得的初步数据显示，删除AASS/Aass 限制GA 1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， 可能是治疗GA 1的安全靶点。因此，本提案的总体目标是确定新的 AASS的赖氨酸-酮戊二酸还原酶（LOR）结构域的小分子抑制剂， 药物化学优化。在AIM 1中，研究人员将通过以下方法确定酶抑制剂候选物： 小分子高通量筛选（HTS）和计算（虚拟）筛选， 获得了2.2 μ LOR晶体结构。然后，利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，以验证新的命中类似物 as drug-like药物scaffolds脚手架.所有来自HTS和虚拟筛选的有效命中将在AIM 2中进一步评估， 以生成具有良好药物化学性质的商业化合物的优先级列表。在AIM中 将通过监测建立的GA 1细胞模型，在体外检测3种选定的经验证的命中分子。 用于抑制LOR和疾病的生物标志物。结合起来，这三个目标将产生不仅高度 可以进一步开发用于治疗GA 1的经验证的LOR的命中抑制剂，但也是重要的另外的 赖氨酸降解的生物化学和生理学数据。

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.