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：
7805441
负责人：
Robert Gerd Salomon
金额：
$ 31.09万
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/7805441
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 Fluoresceins Fostering Free Radicals Generations Genetic Goals Guanosine Human Hydrazine Hydrazines 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 age related alkoxyl radical aqueous base capillary catalyst chemical reaction chemical synthesis cofactor cytotoxic deacylation design diene human tissue in vitro Model inhibitor/antagonist interest macula 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）：该项目的总体目的是为治疗措施的合理设计提供基本的机械基础，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品的形成，从而损害与年龄相关的黄斑变性导致视网膜的某些有毒产品。直接的目标是了解多不饱和脂肪酰基衍生物的氧化碎片反应，该反应产生了氧化截断的磷脂和脂肪族脂质片段的复杂混合物。这些破碎产物表现出多种多样的病理生物学活性。特别令人感兴趣的是产生诱变的环氧基因烯碱和细胞毒性羟基烷烯。了解其一代中涉及的反应性中间体的化学知识对于了解环境或遗传因素如何促进其形成很重要。例如，我们确定的所有中间体都需要催化活性的金属离子在生物条件下进行碎片化。我们尚未研究的一种类型的中间体被认为是自发的碎片，而无需催化。但是，此类中间体尚未得到充分的特征。我们将通过化学合成来制备纯表征的样品。如果我们确认此类中间体还需要金属离子催化的假设，那么一种治疗策略将是去除或排毒这种金属离子。了解在生物条件下发生的主要碎片化产物的进一步转化，包括氧化，脱酰化和蛋白质内收，因为这些过程会产生生物学活跃的二级产品。例如，我们已经表明，源自二十六六烯酸的羟基磷脂的蛋白质加合物启动黄斑变性，并促进毛细血管的病理发芽到视网膜中。该项目着重于研究在氧化碎片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）实际涉及的假定中间体，如果是的，则（2）它们的分解产生了哪些产品，以及（3）通过哪种机制碎片碎片？在某些情况下，它们将被困为稳定的衍生物以确认其参与。为了提供大量的一些反应性中间体，设计和执行了明确的总合成。正宗样品被用作建立用于检测和量化氧化反应产物混合物中间体水平的方法的标准。他们的一代并转化为有毒或无害的最终产品。我们正在确定（1）环境的影响，例如在不同的细胞器中发现的环境或与病理条件，（2）辅因子水平相关的环境，或（3）氧化启动系统和抑制剂，对反应性中间体的产生以及各种途径在随后的转化中的相对性。公共卫生相关性：磷脂，主要的构建基块人体组织，被氧气产生可能有毒的碎片攻击和破裂。例如，其中一些碎片修改了视网膜中的蛋白质，从而导致免疫系统攻击和破坏视网膜。为了为设计策略设计合理的基础，该项目将准确确定这种磷脂的氧化碎片如何发生，碎片是什么以及其毒性中涉及哪些化学反应。