Reactive Intermediates of Oxidative Lipid Fragmentation

氧化脂质断裂的反应中间体

基本信息

批准号：
8055311
负责人：
Robert Gerd Salomon
金额：
$ 29.84万
依托单位：
CASE WESTERN RESERVE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2006
资助国家：
美国
起止时间：
2006-05-01 至 2014-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8055311
关键词：
1-Alkyl-2-acetylglycerophosphocholine Esterase Abbreviations Acetylcysteine Acids Address Adenosine Age related macular degeneration Aldehydes Arachidonic Acids Ascorbic Acid Atherosclerosis Biological Biomimetics Blood capillaries Carboxylic Acids Catalysis Chemistry Complementary DNA Complex Complex Mixtures Dicarboxylic Acids Dicyclohexylcarbodiimide Docosahexaenoic Acids Environment Environmental Risk Factor Epoxy Compounds Esters Evolution Exhibits Eye Fluorescein Fluorescein-5-isothiocyanate Fostering Free Radicals Generations Genetic Goals Guanosine Human Hydrazine Hydrogen Hydrogen Peroxide Hydroxyl Radical Immune system Immunoglobulin M Individual Interleukins Ions Isothiocyanates Knowledge Lecithin Linoleic Acids Lipid Peroxides Lipids Lipoproteins Liquid Chromatography Low-Density Lipoproteins Macular degeneration Malondialdehyde Mass Spectrum Analysis Measures Membrane Metals Methods Molecular Conformation Monocyte Chemoattractant Proteins N-methylacetamide-oxotremorine M Nitric Oxide Nitric Oxide Synthase Nuclear Octanols Organelles Oxidation-Reduction Oxides Oxygen PAPOLB gene Partition Coefficient Pathway interactions Pentetic Acid Peroxidases Phase Phosphate Buffer Phospholipase Phospholipases A Phospholipids Phosphorylcholine Photoreceptors Photosensitizing Agents Physiological Platelet Activating Factor Polyacrylamide Gel Electrophoresis Polyunsaturated Fatty Acids Process Production Proteins Pyrans Reaction Relative (related person)Retina Retinal Rod Outer Segments Route Saline Sampling Scheme Serum Albumin Sodium Dodecyl Sulfate Spectrometry, Mass, Electrospray Ionization Structure Structure of retinal pigment epithelium Superoxide Dismutase System Testing Therapeutic Tocopherols Toxic effect Trifluoroacetate Vesicle Visible Radiation Vitamin E Water adduct alkoxyl radical aqueous base capillary catalyst chemical reaction chemical synthesis cofactor cytotoxic deacylation design diene human tissue in vitro Model inhibitor/antagonist interest morpholine novel oxidation prevent public health relevance pyridine tetrahydrofuran

项目摘要

DESCRIPTION (provided by applicant): The overall objective of the project is to provide a fundamental mechanistic basis for the rational design of therapeutic measures to prevent or ameliorate the pathological consequences of lipid oxidation, for example, by blocking the formation of certain toxic products that damage the retina resulting in age-related macular degeneration. The immediate goal is to understand oxidative fragmentation reactions of polyunsaturated fatty acyl derivatives that generate a complex mixture of oxidatively truncated phospholipids and aliphatic lipid fragments. These fragmentation products exhibit diverse and often pathological biological activities. Of particular interest is the production of mutagenic epoxyalkenals and cytotoxic hydroxyalkenals. Knowledge of the chemistry of the reactive intermediates involved in their generation is important for understanding how environmental or genetic factors can promote their formation. For example, all of the intermediates that we have identified require catalytically active metal ions to undergo fragmentation under biological conditions. One type of intermediate that we have yet to study is believed to spontaneously fragment, without the need for catalysis. However, such intermediates have not been thoroughly characterized. We will prepare pure well characterized samples by chemical synthesis. If we confirm our hypothesis that metal ion catalysis is also required for such intermediates, then one therapeutic strategy would be to remove or detoxify such metal ions. Knowledge of the further transformations of the primary fragmentation products that occur under biological conditions, including oxidation, deacylation, and protein adduction is important because these processes produce biologically active secondary products. For example, we have shown that the protein adducts of hydroxyalkenal phospholipids derived from docosahexaenoic acid initiate macular degeneration and also promote the pathological sprouting of capillaries into the retina. The project focuses on studying key intermediates that are not stable under the oxidative fragmentation reaction conditions. Three basic questions are being addressed: (1) are the putative intermediates actually involved, and if so (2) what products are generated by their decomposition and (3) by what mechanism(s) do they fragment? In some cases, they will be trapped as stable derivatives to confirm their involvement. To provide ample quantities of some reactive intermediates, unambiguous total syntheses are designed and executed. The authentic samples are being used as standards for establishing methods for detecting and quantifying levels of the intermediates in oxidation reaction product mixtures. Their generation and conversion into toxic or innocuous end products is being investigated. We are determining the influences of (1) environments such as those found in different organelles or associated with pathological conditions, (2) levels of cofactors, or (3) oxidation initiating systems and inhibitors, on the production of the reactive intermediates and on the relative importance of various pathways for their subsequent transformations. PUBLIC HEALTH RELEVANCE: Phospholipids, major building blocks human tissue, are attacked and broken apart by oxygen producing fragments that can be toxic. For example, some of these fragments modify proteins in the retina causing the immune system to attack and destroy the retina. To provide a rational basis for the design of therapeutic strategies, this project will determine exactly how such oxidative fragmentation of phospholipids occurs, what the pieces are, and what are some of the chemical reactions involved in their toxicity.

描述（由申请人提供）：该项目的总体目标是为合理设计治疗措施提供基本机制基础，以预防或改善脂质氧化的病理后果，例如，通过阻止某些有毒产物的形成，损害视网膜，导致年龄相关性黄斑变性。近期目标是了解多不饱和脂肪酰基衍生物的氧化断裂反应，该反应产生氧化截短的磷脂和脂肪族脂质片段的复杂混合物。这些碎片产物表现出多种且常常是病理性的生物活性。特别令人感兴趣的是诱变环氧烯醛和细胞毒性羟基烯醛的生产。了解其生成过程中涉及的反应中间体的化学性质对于理解环境或遗传因素如何促进其形成非常重要。例如，我们发现的所有中间体都需要催化活性金属离子在生物条件下进行裂解。我们尚未研究的一种中间体被认为会自发断裂，无需催化。然而，此类中间体尚未得到彻底表征。我们将通过化学合成制备纯的、表征良好的样品。如果我们证实我们的假设，即此类中间体也需要金属离子催化，那么一种治疗策略就是去除或解毒此类金属离子。了解在生物条件下发生的初级断裂产物的进一步转化（包括氧化、脱酰化和蛋白质加合）非常重要，因为这些过程会产生具有生物活性的次级产物。例如，我们已经证明，二十二碳六烯酸衍生的羟基烯醛磷脂的蛋白质加合物会引发黄斑变性，并促进毛细血管病理性发芽进入视网膜。该项目重点研究氧化裂解反应条件下不稳定的关键中间体。正在解决三个基本问题：（1）假定的中间体是否实际参与，如果是的话（2）它们的分解产生什么产物，（3）它们通过什么机制破碎？在某些情况下，它们会被困为稳定的衍生品以确认其参与。为了提供充足数量的一些反应中间体，设计并执行了明确的全合成。真实样品被用作建立检测和定量氧化反应产物混合物中中间体水平的方法的标准。正在研究它们的产生和转化为有毒或无毒最终产品的情况。我们正在确定 (1) 环境（例如在不同细胞器中发现的或与病理条件相关的环境）、(2) 辅因子水平或 (3) 氧化引发系统和抑制剂对反应中间体的产生和对反应中间体的影响。各种途径对其后续转化的相对重要性。公共卫生相关性：磷脂是人体组织的主要组成部分，会受到氧气的攻击和分解，产生有毒的碎片。例如，其中一些片段会修改视网膜中的蛋白质，导致免疫系统攻击并破坏视网膜。为了为治疗策略的设计提供合理的基础，该项目将准确确定磷脂的氧化断裂是如何发生的、碎片是什么，以及与其毒性有关的一些化学反应是什么。