Novel Antioxidant Defenses and Redox Maintenance Systems in Bdelloid Rotifers

蛭形轮虫的新型抗氧化防御和氧化还原维持系统

• 批准号: 8770343
• 负责人: DAVID B MARK WELCH
• 金额: $ 20.06万
• 依托单位: MARINE BIOLOGICAL LABORATORY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8770343
• 关键词: Aging; Aging-Related Process; Animal Model; Animals; Antioxidants; Apoptosis; Biochemical; Biological Assay; Biological Markers; Biological Models; Caenorhabditis elegans; Cell physiology; Comparative Study; Complement; DNA Double Strand Break; Desiccation; Disease; Disulfides; Environment; Equilibrium; Escherichia coli; Evolution; Exposure to; Female; Fertility; Foundations; Future; Gene Expression Profile; Gene Transfer; Genes; Genetic; Genome; Genomics; Glutathione; Glutathione Disulfide; Goals; Health; Homeostasis; Horizontal Gene Transfer; Human; Hydrogen Peroxide; Individual; Invertebrates; Investigation; Investments; Ionizing radiation; Knock-out; Link; Longevity; Maintenance; Malignant Neoplasms; Mediating; Metabolic; Methods; Modeling; Nematoda; Organism; Outcome; Oxidation-Reduction; Oxidative Stress; Oxidoreductase; Pathway interactions; Pattern; Peroxides; Physiological; Play; Polyamines; Production; Property; Proteins; RNA Interference; Radiation; Reactive Oxygen Species; Recovery; Research; Resistance; Role; Series; Staging; Stress; Sulfhydryl Compounds; System; Testing; Trypanosoma; Work; age related; base; biological adaptation to stress; cost; dithiol; experience; gene synthesis; genome analysis; improved; in vitro activity; insight; killings; knock-down; novel; novel strategies; oxidation; oxidative damage; public health relevance; repaired; response; restoration; senescence; small molecule; trypanothione

DESCRIPTION (provided by applicant): Damage from reactive oxygen species (ROS) and perturbations in thiol redox cycling play a major role in aging, senescence, and apoptosis and drive the evolution of antioxidant defense (AOD) systems. However, AOD and redox maintenance incur metabolic and physiological costs, and a balance exists between the cost of damage and the cost of repair. Organisms that routinely experience highly stressful and mutagenic environments are under selection for an increased investment in developing novel means of AOD and redox maintenance. Bdelloid rotifers, small aquatic invertebrates of similar complexity to nematodes, are one such group. Bdelloids inhabit ephemerally aquatic environments and can survive repeated rounds of desiccation without a decrease in hydrated lifespan. In some species, females that have been through desiccation have increased lifespan and fecundity. Bdelloids are also among the most radiation resistant animals known, capable of repairing many hundreds of DNA double strand breaks after exposure to levels of ionizing radiation (IR) that would sterilize or kill any established animal model species. The extreme resistance of bdelloids to IR is almost certainly a consequence of their ability to tolerate the oxidative stress incurred during and recovering from desiccation. This is further supported by the observation that bdelloids are very resistant to hydrogen peroxide, with no observable effect at concentrations of H2O2 lethal to nematodes. Exposure to H2O2 at concentrations above the LC50 for nematodes increases lifespan and fecundity in bdelloids. Analysis of genomes and transcriptomes has revealed that bdelloids express multiple copies of genes for the synthesis and reduction of a glutathione-like polyamine dithiol, trypanothione, otherwise known only from kinetoplastid protozoans such as trypanosomes. This R21-scale project will characterize this novel thiol redox system and assess its contribution to different lifespan and fecundity outcomes after oxidative stress in rotifers and model organisms. The guiding hypothesis is that investigating a novel group of animals where redox maintenance AOD systems are maximized will provide new insights and approaches to increasing lifespan and healthspan. The first aim will test the hypothesis that trypanothione plays a major role in the bdelloid AOD and redox maintenance response to oxidative stress and aging, using a series of genetic and biochemical analyses. The second aim will test the hypothesis that the trypanothione system is sufficient to confer enhanced resistance to oxidative stress and is in part responsible for the observation of increased lifespan and fecundity, using RNAi to knock down trypanothione synthase in rotifers and by expressing the synthase and reductase in E. coli and C. elegans followed by exposure to oxidative stress. The long-term objective of this work is to establish bdelloid rotifers as a particularly advantageous model for comparative studies of redox maintenance and AOD systems as they relate to aging, with the goal of developing methods for enhancing these systems in other species, including standard aging models.

描述（由申请人提供）：活性氧（ROS）造成的损伤和硫醇氧化还原循环的扰动在衰老、衰老和细胞凋亡中发挥着重要作用，并驱动抗氧化防御（AOD）系统的进化。然而，AOD 和氧化还原维持会产生代谢和生理成本，并且损伤成本和修复成本之间存在平衡。经常经历高压力和致突变环境的生物体正在被选择，以增加开发新的 AOD 和氧化还原维持方法的投资。蛭形轮虫是一种小型水生无脊椎动物，其复杂性与线虫相似，就是其中之一。蛭形动物栖息在短暂的水生环境中，可以在反复的干燥中生存，而不会缩短水合寿命。在某些物种中，经历过干燥的雌性会延长寿命和繁殖力。蛭形动物也是已知最抗辐射的动物之一，在暴露于电离辐射 (IR) 水平后能够修复数百个 DNA 双链断裂，而电离辐射 (IR) 水平足以杀死任何已建立的动物模型物种。蛭形动物对红外线的极端抵抗力几乎可以肯定是它们能够耐受干燥过程中和从干燥中恢复过程中产生的氧化应激的结果。蛀虫对过氧化氢具有很强的抵抗力，在对线虫致死的 H2O2 浓度下没有观察到影响，这一观察结果进一步支持了这一点。接触线虫浓度高于 LC50 的 H2O2 可延长蛭形动物的寿命和繁殖力。对基因组和转录组的分析表明，蛭形动物表达多个基因拷贝，用于合成和还原谷胱甘肽样多胺二硫醇、锥硫酮，而锥硫酮仅存在于动质体原生动物（如锥虫）中。这个 R21 规模的项目将表征这种新型硫醇氧化还原系统，并评估其对轮虫和模式生物氧化应激后不同寿命和繁殖力结果的贡献。指导性假设是，研究氧化还原维持 AOD 系统最大化的一组新动物将为延长寿命和健康提供新的见解和方法。第一个目标将使用一系列遗传和生化分析来检验锥硫酮在蛭形 AOD 和氧化应激和衰老的氧化还原维持反应中发挥重要作用的假设。第二个目标将测试以下假设：锥硫酮系统足以增强对氧化应激的抵抗力，并在一定程度上负责观察到寿命和繁殖力的增加，使用 RNAi 敲低轮虫中的锥硫酮合酶并通过表达合酶和还原酶在大肠杆菌和线虫中，然后暴露于氧化应激。这项工作的长期目标是建立蛭形轮虫作为氧化还原维持和 AOD 系统比较研究的特别有利的模型，因为它们与衰老有关，目标是开发在其他物种中增强这些系统的方法，包括标准衰老模型。