Development of Chemical Tools to Probe and Inhibit Iron-Induced Oxidative Stress

开发化学工具来探测和抑制铁诱导的氧化应激

• 批准号: 7825260
• 负责人: Katherine J. Franz
• 金额: $ 30.12万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2013-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7825260
• 关键词: Adverse effects; Affinity; Age related macular degeneration; Aging; American; Antioxidants; Atherosclerosis; Binding; Biochemical Markers; Biological Assay; Cell Culture Techniques; Cell Survival; Cells; Characteristics; Chelating Agents; Chelation Therapy; Chemicals; Chemistry; Complex; DNA; Degenerative Disorder; Development; Diabetes Mellitus; Disease; Esters; Exposure to; Face; Facilities and Administrative Costs; Family; Fluorescent Probes; Free Radicals; Generations; Goals; Homeostasis; Hydrogen Peroxide; Hydroxyl Radical; Hydroxylation; Imagery; Imaging Device; In Vitro; Inflammation; Ions; Iron; Iron Chelating Agents; Iron Chelation; Ischemia; Life; Ligands; Lipid Peroxidation; Macular degeneration; Masks; Measures; Metals; Methodology; Modification; Nerve Degeneration; Neurons; Oxidative Stress; Oxygen; Parkinson Disease; Phenols; Post-Translational Protein Processing; Process; Prodrugs; Production; Property; Reaction; Reagent; Reperfusion Therapy; Role; Side; Site; Source; Structure; Structure of retinal pigment epithelium; Testing; Toxic effect; UV Radiation Exposure; United States; analog; base; cost; design; experience; fluorophore; human disease; iron chelation therapy; lipophilicity; metalloenzyme; oxidative damage; protective effect; public health relevance; stoichiometry; tool

DESCRIPTION (provided by applicant): Oxidative stress is implicated in a wide variety of diseases, including diabetes, inflammation, post- ischemia reperfusion, UV exposure, atherosclerosis, aging, macular degeneration, and neurodegeneration. Lipid peroxidation, DNA hydroxylation, and protein modification are markers of oxidative stress that result primarily from reactions with the highly reactive hydroxyl radical, OH, itself a product of iron-catalyzed reactions with oxygen species. Whereas iron is an essential and beneficial component of healthy cells, this deleterious reactivity suggests that labile iron in the cell provokes serious damage. Our long-term goals are to develop medicinal iron chelating agents that selectively inhibit this deleterious iron-promoted damage at the site of oxidative stress while avoiding toxicity commonly associated with iron chelation therapy. In addition to being potentially useful medicinal agents, the proposed pro-chelators will also serve as fluorescent probes to visualize the role of iron in oxidative stress in living cells. In order to achieve these goals, this proposal focuses on the chemistry required to synthesize (Specific Aim 1) and characterize (Specific Aim 2) new families of pro-chelators in which a masking group blocks key metal-binding functionalities of otherwise high-affinity iron chelators. The masking groups are boronate esters, since these groups are deprotected by hydrogen peroxide, a component of oxidative stress. In Specific Aim 3 we develop fluorescent analogs to probe iron-promoted oxidative stress inside living cells. Once the synthesis and characterization establishes their in vitro properties, this new class of molecules will be tested in cell culture to validate their efficacy for protecting cells against oxidative damage by removing iron at the source of oxidative stress (Specific Aim 4). Currently available chelation therapies face toxic side reactions that alter healthy metal distribution and inhibit critical metalloenzymes. In the absence of hydrogen peroxide, the proposed masked chelators will be innocuous bystanders that will not interfere with beneficial metals. Disease conditions that increase hydrogen peroxide levels, however, activate and unmask a potent chelator that sequesters and removes the iron that is the source of OH generation. Unlike typical antioxidants that neutralize harmful free radicals only after they are produced, effective iron chelators can eliminate their production altogether by disabling the source. The molecules proposed herein represent a promising new strategy with potential impact on a number of human diseases, especially those where normal metal ion homeostasis is impaired or where aberrant metal accumulation takes place. Degenerative diseases like Parkinson's disease and age-related macular degeneration are just two examples. PUBLIC HEALTH RELEVANCE: Over a million Americans suffer from Parkinson's disease, a progressive form of neurodegeneration with no known cure that is estimated to cost $25 billion per year in direct and indirect costs in the United States. Although its cause is not known, emerging hypotheses implicate iron-induced oxidative stress as a source of neuronal damage. The new pro-chelator molecules proposed herein are designed to protect cells against precisely this type of damage, and therefore represent a promising new strategy with the potential to impact not only Parkinson's disease, but also other neurodegenerative conditions, age-related macular degeneration, and a wide variety of other human diseases associated with oxidative stress.

描述（由申请人提供）：氧化应激与多种疾病有关，包括糖尿病、炎症、缺血再灌注后、紫外线暴露、动脉粥样硬化、衰老、黄斑变性和神经变性。脂质过氧化、DNA 羟基化和蛋白质修饰是氧化应激的标志，这些氧化应激主要是由与高活性羟基自由基 (OH) 的反应引起的，OH 本身是铁催化与氧物质反应的产物。虽然铁是健康细胞的重要且有益的成分，但这种有害的反应性表明细胞中不稳定的铁会引起严重损害。我们的长期目标是开发药用铁螯合剂，选择性抑制氧化应激部位铁促进的有害损伤，同时避免与铁螯合疗法常见的毒性。除了作为潜在有用的药物外，所提出的前螯合剂还将用作荧光探针，以可视化铁在活细胞氧化应激中的作用。为了实现这些目标，本提案重点关注合成（具体目标 1）和表征（具体目标 2）新的前螯合剂家族所需的化学，其中掩蔽基团阻断其他高亲和力铁螯合剂的关键金属结合功能。掩蔽基团是硼酸酯，因为这些基团被过氧化氢（氧化应激的一种成分）脱保护。在特定目标 3 中，我们开发了荧光类似物来探测活细胞内铁促进的氧化应激。一旦合成和表征确定了它们的体外特性，这类新型分子将在细胞培养物中进行测试，以验证它们通过去除氧化应激源头的铁来保护细胞免受氧化损伤的功效（具体目标 4）。目前可用的螯合疗法面临着毒副反应，这些反应会改变健康的金属分布并抑制关键的金属酶。在没有过氧化氢的情况下，所提出的掩蔽螯合剂将是无害的旁观者，不会干扰有益金属。然而，增加过氧化氢水平的疾病会激活并暴露出一种有效的螯合剂，该螯合剂可以隔离并去除作为 OH 生成来源的铁。与仅在有害自由基产生后才将其中和的典型抗氧化剂不同，有效的铁螯合剂可以通过禁用来源来完全消除其产生。本文提出的分子代表了一种有前途的新策略，对许多人类疾病有潜在影响，特别是那些正常金属离子稳态受损或发生异常金属积累的疾病。帕金森病和年龄相关性黄斑变性等退行性疾病只是两个例子。公共健康相关性：超过 100 万美国人患有帕金森病，这是一种进行性神经退行性疾病，目前尚无已知的治疗方法，估计在美国每年造成 250 亿美元的直接和间接费用。尽管其原因尚不清楚，但新出现的假设表明铁诱导的氧化应激是神经元损伤的一个来源。本文提出的新的前螯合剂分子旨在保护细胞免受此类损伤，因此代表了一种有前景的新策略，不仅有可能影响帕金森病，还可能影响其他神经退行性疾病、年龄相关性黄斑变性以及与氧化应激相关的多种其他人类疾病。