Regulation of mitochondrial function by folate enzyme ALDH1L2 in health and disease

叶酸酶 ALDH1L2 在健康和疾病中对线粒体功能的调节

• 批准号: 10597021
• 负责人: SERGEY A KRUPENKO
• 金额: $ 47.58万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-01 至 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10597021
• 关键词: Acids; Amino Acids; Anabolism; Animal Model; Binding; Carbon; Carbon Dioxide; Cells; Coenzyme A; Cytoplasm; Dermatitis; Diagnosis; Diet; Disease; Enzymes; Equilibrium; Etiology; Fathers; Fibroblasts; Folic Acid; Folic Acid Deficiency; Formyltetrahydrofolates; Functional disorder; Gene Duplication; Generations; Genes; Glutathione Disulfide; Health; High Fat Diet; Human; Hydrolase; Impairment; Individual; Knockout Mice; Knowledge; Link; Lipids; Maintenance; Mediating; Metabolic; Metabolism; Mitochondria; Mus; Mutation; NADP; Neurologic; Outcome; Oxidation-Reduction; Oxidative Stress; Pathway interactions; Patients; Phenotype; Physiological; Pilot Projects; Play; Production; Proliferating; Reaction; Regulation; Role; Sjogren-Larsson Syndrome; Spleen; Sulfhydryl Compounds; Syndrome; Testing; Tetrahydrofolates; autism spectrum disorder; cell type; clinically relevant; diet-induced obesity; dietary; experimental study; fatty acid metabolism; fatty acid oxidation; folic acid metabolism; human disease; insight; knockout gene; metabolic phenotype; metabolomics; mitochondrial dysfunction; mutant; oxidation; rare genetic disorder; response; restoration

The physiological role of the mitochondrial folate enzyme ALDH1L2, discovered by the PI's lab in 2010, is not well understood. This enzyme catalyzes the reaction: NADP+ + 10-formyltetrahydrofolate → NADPH + CO2 + tetrahydrofolate, which can be important for the mitochondrial NADPH production from the oxidation of folate- bound one-carbon groups. In support of this function, our recent gene knockout experiments show that deletion of Aldh1l2 in mice causes increased oxidative stress. Furthermore, Aldh1l2-/- mice develop ulcerative dermatitis, and have highly enlarged (4-fold) spleen and extensively altered metabotype. The mechanistic basis underlying these phenotypes is currently unknown but has clinical relevance given the recent identification of patients with ALDH1L2 mutations who were diagnosed with a rare neurocutaneous disease or autistic spectrum disorder. Our metabolomics analysis of patient's fibroblasts identified dramatic changes in the cellular lipid repertoire, the outcome most likely caused by the impairment of mitochondrial CoA-dependent fatty acid metabolism. This leads to mitochondrial dysfunction, which is manifested as insufficient energy production and oxidative stress. In further support of this mechanism, fibroblasts from ALDH1L2-deficient patients have fragmented mitochondria and show the accumulation of lipid droplets. Importantly, the restoration of the ALDH1L2 enzyme in these fibroblasts rescues the phenotype and metabotype, making these cells similar to fibroblasts from healthy individuals. Based on these findings, we hypothesize that ALDH1L2 serves distinct metabolic function in the cell, the maintenance of redox state through the mitochondrial NADPH generation linked to the folate cycle. The loss of ALDH1L2 leads to mitochondrial dysfunction, energy disbalance and oxidative stress. Thus, deleterious mutations in the ALDH1L2 gene are underlying cause of mitochondria-related human disorders/diseases. This proposal will determine the role of ALDH1L2 in cellular metabolism and will link its mutations as causative factor of human diseases through the following aims: (1) Test the hypothesis that ALDH1L2 maintains mitochondrial redox balance and controls coenzyme A biosynthesis and fatty acid oxidation. (2) Define the role of ALDH1L2 in partitioning of one-carbon groups between energy production or mitochondria to cytoplasm shuttling. (3) Establish ALDH1L2 deficiency as the cause of rare genetic disorders in humans and explore underlying mechanisms. It is now clear that mitochondrial dysfunction is an important component in the pathophysiology of numerous diseases that had not been previously identified. The role of ALDH1L2 in maintenance of mitochondrial function, as well as in mitochondria-related diseases, is largely unexplored. This proposal will fill this knowledge gap and will provide mechanistic insight into the role of ALDH1L2 in human diseases.

PI 实验室于 2010 年发现的线粒体叶酸酶 ALDH1L2 的生理作用尚不清楚。该酶催化以下反应：NADP+ + 10-甲酰四氢叶酸 → NADPH + CO2 + 四氢叶酸，这对于通过叶酸结合的一碳基团的氧化产生线粒体 NADPH 非常重要。为了支持这一功能，我们最近的基因敲除实验表明，小鼠中 Aldh1l2 的缺失会导致氧化应激增加。此外，Aldh1l2-/- 小鼠会出现溃疡性皮炎，脾脏高度增大（4 倍），代谢型也发生广泛改变。这些表型背后的机制基础目前尚不清楚，但鉴于最近发现患有 ALDH1L2 突变的患者被诊断患有罕见的神经皮肤疾病或自闭症谱系障碍，因此具有临床相关性。我们对患者成纤维细胞的代谢组学分析发现细胞脂质库发生了巨大变化，这一结果很可能是由线粒体 CoA 依赖性脂肪酸代谢受损引起的。这导致线粒体功能障碍，表现为能量产生不足和氧化应激。为了进一步支持这一机制，来自 ALDH1L2 缺陷患者的成纤维细胞具有碎片化的线粒体并显示出脂滴的积累。重要的是，这些成纤维细胞中 ALDH1L2 酶的恢复挽救了表型和代谢型，使这些细胞与健康个体的成纤维细胞相似。基于这些发现，我们假设 ALDH1L2 在细胞中具有独特的代谢功能，通过与叶酸循环相关的线粒体 NADPH 生成来维持氧化还原状态。 ALDH1L2 的缺失会导致线粒体功能障碍、能量失衡和氧化应激。因此，ALDH1L2 基因中的有害突变是线粒体相关人类病症/疾病的根本原因。该提案将通过以下目标确定 ALDH1L2 在细胞代谢中的作用，并将其突变与人类疾病的致病因素联系起来：（1）检验 ALDH1L2 维持线粒体氧化还原平衡并控制辅酶 A 生物合成和脂肪酸氧化的假设。 (2) 定义 ALDH1L2 在能量产生或线粒体与细胞质穿梭之间的一碳基团分配中的作用。 (3) 确定 ALDH1L2 缺陷是人类罕见遗传性疾病的原因，并探索潜在机制。现在已经清楚，线粒体功能障碍是许多以前未发现的疾病的病理生理学的重要组成部分。 ALDH1L2 在维持线粒体功能以及线粒体相关疾病中的作用很大程度上尚未被探索。该提案将填补这一知识空白，并为 ALDH1L2 在人类疾病中的作用提供机制见解。

项目成果

Is ALDH1L1 Elevated in Lung Cancer? Comment on: Lee, S.-H.; et al. "The Combination of Loss of ALDH1L1 Function and Phenformin Treatment Decreases Tumor Growth in KRAS-Driven Lung Cancer" Cancers 2020, 12, 1382.

• DOI: 10.3390/cancers13071691
• 发表时间: 2021-04-02
• 期刊: Cancers
• 影响因子: 5.2
• 作者: Krupenko SA;Sharma J
• 通讯作者: Sharma J

Aldh1l2 knockout mouse metabolomics links the loss of the mitochondrial folate enzyme to deregulation of a lipid metabolism observed in rare human disorder.

• DOI: 10.1186/s40246-020-00291-3
• 发表时间: 2020-11-09
• 期刊: Human genomics
• 影响因子: 4.5
• 作者: Krupenko NI;Sharma J;Pediaditakis P;Helke KL;Hall MS;Du X;Sumner S;Krupenko SA
• 通讯作者: Krupenko SA