"Isocitrate dehydrogenase (IDH) mutations as drivers of organelle stress and dysfunction"

“异柠檬酸脱氢酶 (IDH) 突变是细胞器应激和功能障碍的驱动因素”

• 批准号: 10380403
• 负责人: Christal Dyane Sohl
• 金额: $ 7.74万
• 依托单位: SAN DIEGO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10380403
• 关键词: Acute Myelocytic Leukemia; Affect; Automobile Driving; Catalysis; Chemicals; Chondrosarcoma; Clinic; Communication; Cytosol; DNA; Disease; Drug Targeting; Enzymes; Functional disorder; Glioma; Goals; Grant; Health; Isocitrate Dehydrogenase; Isocitrates; Kinetics; Lipids; Location; Malignant Neoplasms; Metabolic; Mitochondria; Modification; Molecular; Mutation; NADP; Organelles; Oxidative Stress; Pathway interactions; Patients; Point Mutation; Production; Prognosis; Property; Protein Dynamics; Regulation; Reporting; Research; Role; Signal Transduction; Stress; Structure; Technology; Tumor Suppressor Genes; Variant; Work; alpha ketoglutarate; histone demethylase; inhibitor/antagonist; lipid biosynthesis; loss of function; mutant; peroxisome; predictive tools; programs; therapeutic target; tool

ABSTRACT/SUMMARY The consequences of mutations in isocitrate dehydrogenase 1 (IDH1) and IDH2 in cancer are unusual. Though these mutations confer a loss of function of the normal activity of the NADP+-dependent conversion of isocitrate to α-ketoglutarate (αKG), mutant IDH is more of an oncogene than tumor suppressor, as a neomorphic activity is also conferred: the NADPH-dependent production of oncometabolite D-2-hydroxyglutarate (D2HG) from αKG. D2HG inhibits αKG-dependent enzymes like DNA and histone demethylases, and NADPH depletion results in oxidative stress. A variety of point mutations affecting residue R132 in IDH1 can grant these catalytic properties, causing prominent structural modifications that allow mutant IDH1 to be a bona fide drug target. Indeed, a se- lective allosteric mutant IDH1 inhibitor is now in the clinic. Both mutant and WT IDH1 localize to the cytosol and peroxisomes, while IDH2 is found in the mitochondria, raising the possibility of organelle-specific consequences of IDH mutations, though this has not yet been explored. Interestingly, there is a communication pipeline between the peroxisomes and mitochondria in that they share an interconnected role in lipid processing and mitigation of oxidative stress, though the role of IDH in this communication is not yet known. To date, several limitations have restricted the rigor of mutant IDH studies. First, the catalytic and inhibition profile for R132H IDH1 is extrapolated to other disease-relevant IDH1 mutants, though we show several mutants have very unique profiles. Second, the role of NADPH depletion, and thus oxidative stress, is often overlooked in favor of studying consequences of D2HG. Third, studies focus on the global/cytosolic contributions of mutant IDH1, ignoring its role of sole NADPH and αKG producer in this organelle. However, we report evidence of dysfunctional lipid biosynthetic pathways in the peroxisomes upon introduction of cellular IDH1 mutations. The overall goal of our research program is to determine the mechanisms of metabolic enzyme catalysis, regulation, inhibition, and cellular/orga- nellular function in health and disease, from the chemical to the cellular levels. By leveraging kinetic, structural, cellular, and -omics technologies, we can establish the unique consequences of disease-relevant mutational variants in metabolic enzymes. Here, we have identified critical questions to illuminate the role of mutant IDH1 in disease: 1) How do protein dynamics affect IDH1 catalysis and inhibition? 2) What are the effects of oxidative stress on IDH1 and IDH2? 3) What are the organelle-specific consequences of IDH1 mutations? 4) What are the roles of IDH1 mutations in organelle crosstalk? Through this work, we will uncover fundamental catalytic and regulatory strategies affecting WT and mutant IDH activity, determine the role of IDH1 in the peroxisomes and identify the unique consequences of mutation at this location, and establish the role of mutant IDH1 in facilitating peroxisomal/mitochondrial lipid biosynthesis and oxidative stress signalling. Upon completing this work we will generate valuable new tools, and identify pathways or mechansims that may be therapeutically targetable.

摘要/总结 异柠檬酸脱氢酶1（IDH 1）和IDH 2突变在癌症中的后果是不寻常的。虽然 这些突变导致NADP+依赖性异柠檬酸转化的正常活性丧失 对于α-酮戊二酸（αKG），突变IDH作为一种新变体活性， 还赋予了：αKG产生肿瘤代谢产物D-2-羟基戊二酸（D2 HG）的NADPH依赖性。 D2 HG抑制α KG依赖性酶，如DNA和组蛋白脱甲基酶，NADPH耗竭导致 氧化应激影响IDH 1中残基R132的多种点突变可以赋予这些催化性质， 导致突出的结构修饰，使突变IDH 1成为真正的药物靶点。的确， 选择性变构突变IDH 1抑制剂现已进入临床。突变体和WT IDH 1均定位于胞质溶胶， 过氧化物酶体，而IDH 2在线粒体中发现，提高了细胞器特异性后果的可能性 IDH突变，虽然这还没有被探索。有意思的是， 过氧化物酶体和线粒体，因为它们在脂质加工和减轻 氧化应激，尽管IDH在这种通信中的作用尚不清楚。迄今为止， 限制了突变IDH研究的严谨性。首先，外推R132 H IDH 1的催化和抑制曲线 与其他疾病相关的IDH 1突变体，虽然我们显示几个突变体具有非常独特的概况。第二、 NADPH耗竭和氧化应激的作用常常被忽视，而有利于研究其后果 关于D2 HG第三，研究集中于突变IDH 1的整体/胞质贡献，忽略了其单独的作用。 NADPH和αKG生产者。然而，我们报告的证据表明，功能失调的脂质生物合成 在引入细胞IDH 1突变后，过氧化物酶体中的途径。我们研究的总体目标 程序是确定代谢酶催化，调节，抑制和细胞/器官的机制， 健康和疾病中的细胞功能，从化学到细胞水平。通过利用动能，结构， 细胞和组学技术，我们可以建立疾病相关突变的独特后果， 代谢酶的变体。在这里，我们已经确定了关键问题，以阐明突变IDH 1的作用， 1）蛋白质动力学如何影响IDH 1的催化和抑制？2)氧化的影响是什么 强调IDH 1和IDH 2？3)IDH 1突变的细胞器特异性后果是什么？4)有哪些 IDH 1突变在细胞器串扰中的作用？通过这项工作，我们将揭示基本的催化和 影响WT和突变体IDH活性的调控策略，决定IDH 1在过氧化物酶体中的作用， 确定该位置突变的独特后果，并确定突变IDH 1在促进 过氧化物酶体/线粒体脂质生物合成和氧化应激信号传导。完成这项工作后，我们将 产生有价值的新工具，并确定可能是治疗靶向的途径或机制。