The consequences of human inborn errors in mitochondrial lipoic acid metabolism

项目摘要 先天性代谢缺陷（IEM）是导致儿童患病和死亡的遗传性疾病;然而， 早期发现和干预可以使患有某些IEM的儿童正常发育。硫辛酸缺乏症 是一类新的IEM，可导致代谢性酸中毒、癫痫发作和严重的神经发育障碍。 异常硫辛酸（LA）必须在哺乳动物中从头合成，并且是哺乳动物中必需的辅因子。 中心碳代谢中的基本酶。我们缺乏对LA代谢及其 与代谢程序的关系是治疗LA缺乏患者的主要障碍。 我们有独特的患者样本，通过代谢组学分析，我们发现了一个 与LA缺乏相关的非预期代谢异常数量;包括2- 羟基戊二酸（2-HG）是一种对细胞信号传导和表观遗传调控具有广泛影响的代谢产物。 我们打算描述人类细胞中LA代谢途径的特征，并确定有助于 2-HG升高及其在LA缺乏症中的致病作用。我们有多种LA小鼠模型 缺陷，包括胚胎致死的患者突变的新敲入模型，并且这些 模型，我们打算调查的影响，LA缺陷对胚胎发育。中央 该建议的假设是，在哺乳动物中，由于LA导致的线粒体酶活性受损， 缺乏导致代谢异常，包括2-HG的积累，这有助于 异常发育 如果成功的话，这一提议将对不同酶在蛋白质合成中的作用产生明确的评估。 LA途径对人类细胞中中心代谢通量的影响，从而提供了代谢途径的详细视图。 每种LA相关人类IEM的后果。它还将描述功能失调的LA的影响 在胚胎发生过程中的体内代谢。对患者来源的细胞和小鼠模型的关注应该 增加提案所涉工作的疾病相关性。

PROJECT SUMMARY Inborn errors of metabolism (IEMs) are genetic diseases that cause illness and death in children; however, early detection and intervention permit children with some IEMs to develop normally. Lipoic acid deficiencies are a new class of IEMs that cause metabolic acidosis, seizures and severe neurodevelopmental abnormalities. Lipoic acid (LA) must be synthesized de novo in mammals and is an essential cofactor for fundamental enzymes in central carbon metabolism. Our lack of understanding LA metabolism and its relationship to metabolic programs is the primary obstacle in treating LA deficient patients. We have unique access to patient samples and through metabolomics analysis we have discovered a number of unexpected metabolic abnormalities associated with LA deficiencies; including elevation of 2- hydroxyglutarate (2-HG), a metabolite with wide reaching impacts on cell signaling and epigenetic regulation. We intend to characterize the LA metabolic pathway in human cells and identify mechanisms contributing to the elevation of 2-HG and its pathogenic role in LA deficiencies. We have multiple mouse models of LA deficiency including a novel knock-in model of a patient mutation that are embryonically lethal and with these models, we intend to investigate the impact of LA deficiencies on embryonic development. The central hypothesis of this proposal is that in mammals, impaired activity of mitochondrial enzymes due to LA deficiencies causes aberrant metabolism including accumulation of 2-HG, which contributes to abnormal development. If successful, this proposal will generate a definitive assessment of the role of distinct enzymes in the LA pathway on central metabolic fluxes in human cells, thereby providing a detailed view of the metabolic consequences of each LA-related human IEMs. It will also characterize the effects of dysfunctional LA metabolism in vivo during embryogenesis. The focus on patient-derived cells and mouse models should increase the disease relevance of the work covered in the proposal.