A novel treatment option for disorders of propionate metabolism

项目摘要/摘要 在这个项目中，研究人员提议开发一种治疗丙酸紊乱的新方法。 代谢，如丙酸血症(PA)。PA患者可能出现急性代谢失调 伴有高氨血症，并可发展为多系统障碍或心肌病。这种疾病是由以下原因引起的 PCCA或PCCB双等位基因突变所致的丙酰辅酶A羧化酶(PCC)缺乏症。PCC缺乏症 导致丙酰辅酶A和几种被认为有毒的有机酸的积累。帕 患者从早期干预中受益，该疾病已被列入#年新生儿筛查计划。 很多国家。目前的治疗方法包括急性和慢性干预，其目的都是减少丙酸生成 先兆，但PA的结果仍然是不利的，因为许多患者有长期并发症，可以 影响多个器官系统。此外，饮食管理可能会导致必要的营养不足 支链氨基酸(BCAA)。这说明了对新的治疗选择的需要，这种选择可以进一步 改善宾夕法尼亚州的结果。研究人员假设，通过在促红细胞生成素的上游使用抑制剂 异亮氨酸和缬氨酸的降解途径，可积累有毒的丙酰辅酶A及其衍生物 转移到更易耐受的代谢物中。短链/支链酰辅酶A脱氢酶(SBCAD)和 异丁酰辅酶A脱氢酶(ACAD8)参与支链氨基酸异亮氨酸和缬氨酸的降解， 分别进行了分析。SBCAD和ACAD8缺陷被认为是生化表型，没有临床 意义。已发表的初步数据表明，抑制SBCAD和ACAD8限制了代谢物 PA在细胞系模型中的蓄积。这表明SBCAD和ACAD8是合适的和潜在的 PA治疗的安全靶点。因此，本提案的总体目标是识别和验证小说 适合未来药物化学优化的小分子SBCAD和ACAD8抑制剂候选 分子。在目标1中，研究人员将优化用于筛选SBCAD和ACAD8的酶分析 使用重组蛋白的候选抑制剂。将在AIM 2中确定酶抑制剂候选对象，直至 使用已报道的人类SBCAD和ACAD8晶体结构的计算(虚拟)筛选。全部命中 将在AIM 3中进一步评估来自虚拟放映的广告，以便生成按优先顺序排列的商业广告列表 具有良好药用化学性质的化合物。在AIM 4中，将测试选定的有效HIT分子 通过监测已建立的抑制SBCAD和SBCAD的生物标志物，在体外基于细胞的PA模型中 ACAD8和疾病。结合起来，这四个目标不仅将产生SBCAD和HIT的有效抑制剂 ACAD8，可以进一步优化治疗PA，但也是对生化和 丙酰辅酶A生产的生理学。

Project Summary / Abstract In this project, the investigators propose to develop a novel treatment option for disorders of propionate metabolism such as propionic acidemia (PA). PA patients may present with acute metabolic decompensation with hyperammonemia, and can develop a multisystem disorder or cardiomyopathy. The disorder is caused by propionyl-CoA carboxylase (PCC) deficiency due to biallelic mutations in PCCA or PCCB. PCC deficiency leads to the accumulation of propionyl-CoA and several organic acids, which are thought to be toxic. PA patients benefit from early intervention and the disorder has been included in newborn screening programs in many countries. Current treatments include acute and chronic interventions all aiming to reduce propiogenic precursors, but the outcome of PA is still unfavorable as many patients have long-term complications that can affect multiple organ systems. In addition, dietary management may lead to nutritional deficiencies in essential branched-chain amino acids (BCAAs). This illustrates the need for new therapeutic options that can further improve outcome in PA. The investigators hypothesize that by using inhibitors upstream in the propiogenic isoleucine and valine degradation pathways, accumulation of toxic propionyl-CoA and its derivatives can be diverted into more tolerable metabolites. Short/branched-chain acyl-CoA dehydrogenase (SBCAD) and isobutyryl-CoA dehydrogenase (ACAD8) are involved in the degradation of the BCAAs isoleucine and valine, respectively. Deficiencies SBCAD and ACAD8 are thought to be biochemical phenotypes without clinical significance. Published and preliminary data show that inhibition of SBCAD and ACAD8 limits metabolite accumulation in cell line models for PA. This suggests that SBCAD and ACAD8 are suitable and potentially safe targets for treatment of PA. Thus, the overall objective of this proposal is to identify and validate novel small-molecule SBCAD and ACAD8 inhibitors suitable for future medicinal chemistry optimization to candidate molecules. In AIM 1, the investigators will optimize enzyme assays for the screening of SBCAD and ACAD8 inhibitor candidates using recombinant proteins. Enzyme inhibitor candidates will be identified in AIM 2 through a computational (virtual) screening using reported crystal structures for human SBCAD and ACAD8. All hits from the virtual screening will be further evaluated in AIM 3 in order to generate a prioritized list of commercial compounds with good medicinal chemistry properties. In AIM 4 selected validated hit molecules will be tested in vitro in cell-based models of PA by monitoring established biomarkers for the inhibition of SBCAD and ACAD8, and the disease. Combined, these four aims will yield not only validated hit inhibitors of SBCAD and ACAD8 that can be further optimized for treatment of PA, but also important insights into the biochemistry and physiology of propionyl-CoA production.