Probing functions of NAM and NAD+ salvage in development and aging in C. elegans

探究 NAM 和 NAD 挽救在秀丽隐杆线虫发育和衰老中的功能

• 批准号: 8461742
• 负责人: WENDY HANNA-ROSE
• 金额: $ 5.9万
• 依托单位: PENNSYLVANIA STATE UNIVERSITY, THE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-05-01 至 2014-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8461742
• 关键词: Aging; Anabolism; Animal Model; Animals; Biological; Biological Models; Biological Process; C. elegans genome; Caenorhabditis elegans; Cells; Defect; Development; Developmental Delay Disorders; Enzymes; Event; Functional disorder; Genetic; Gonadal structure; Human; Invertebrates; Light; Longevity; Malnutrition; Mediating; Metabolism; Modeling; Molecular; Molecular Genetics; Mutation; Necrosis; Niacinamide; Nicotinamidase; Nicotinamide adenine dinucleotide; Nicotinic Acids; Organ; Organism; Pathology; Pathway interactions; Pattern; Phenotype; Physiological; Physiology; Protein Isoforms; Regulation; Relative (related person); Resistance; Resolution; Role; Sirtuins; Stress; Supplementation; Time; Tissues; Transgenic Organisms; Vulva; Work; Yeasts; biological adaptation to stress; body system; extracellular; genetic manipulation; in vivo; mutant; novel; protein function; reproductive; reproductive development; reproductive function; response; tool

Human dietary deficiency of the nicotinamide adenine dinucleotide (NAD+) precursors nicotinamide and nicotinic acid (collectively called vitamin B3) causes serious dysfunction of multiple organ systems. Furthermore, increased salvage biosynthesis of NAD+ from nicotinamide promotes longevity in yeast. Yet the molecular mechanisms underlying the organ pathologies are mysterious, and similar lifespan regulation has not been extensively probed in an animal model. The first enzyme in the salvage pathway for NAD+ biosynthesis in invertebrates is nicotinamidase, which converts nicotinamide to nicotinic acid. C. elegans has three nicotinamidases, two PNC-1 isoforms and PNC-2. Mutation of PNC-1 results in distinct developmental defects of the reproductive organs. For example, gonad development is delayed and the uterine vulva 1 (uv1) cells necrose. We aim to decipher how nicotinamidase influences development and longevity in the C. elegans model. I hypothesize that mutation of pnc-1 perturbs nicotinamide and nicotinic acid levels in a tissue-specific manner, which may impact local NAD+ biosynthesis, resulting in specific and separable biological effects. In fact, the observed developmental phenotypes are separable. Uv1 cell necrosis is induced by supplementation with nicotinamide, while the gonad developmental delay of mutants is rescued by supplementation with nicotinic acid. We will determine whether perturbation of nicotinamide, nicotinic acid or NAD+ levels are causative of each phenotype and their relative roles in longevity control using pharmacological and genetic manipulations. I hypothesize that nicotinamidase modulation of NAD+ and nicotinamide levels likely impacts the activity of NAD+ consuming enzymes, which mediate biological effects. We will investigate this hypothesis by studying the impacts of the pathway on the SIR-2.1 NAD+ consumer, which regulates lifespan and stress resistance in C. elegans, and by identifying the NAD+ consumers that mediate the developmental phenotypes. Finally, we have discovered a putative secreted isoform of PNC-1, suggesting an extracellular role for the NAD+ salvage pathway. This discovery is intriguing in light of recent evidence for a systemic role for the first enzyme in the NAD+ salvage pathway in mammalian physiology. We will use transgenic approaches to establish if there is an evolutionarily conserved extracellular function for an NAD+ biosynthetic enzyme in multi-cellular organisms. This work will help elucidate the molecular mechanisms underlying organ pathologies caused by perturbations of NAD+ precursor deficiency and metabolism in humans and will shed light on key aspects of regulation of lifespan promotion by sirtuins.

烟酰胺腺嘌呤二核苷酸（NAD+）前体的人类饮食缺乏 烟酰胺和烟酸（统称称为维生素B3）导致严重功能障碍 多器官系统。此外，从 烟酰胺可促进酵母中的寿命。然而，器官的分子机制 病理是神秘的，类似的寿命调节尚未广泛探测 动物模型。 NAD+生物合成的打捞途径中的第一种酶 无脊椎动物是烟酰胺酶，它将烟酰胺转化为烟酸。秀丽隐杆线虫有 三个烟酰胺酶，两个PNC-1同工型和PNC-2。 PNC-1的突变导致不同的 生殖器官的发育缺陷。例如，性腺发展被延迟 和子宫外阴1（UV1）细胞坏死。我们旨在解密烟酰胺酶如何影响 秀丽隐杆线虫模型中的发展和寿命。我假设PNC-1突变 以组织特异性的方式将烟酰胺和烟酸水平 局部NAD+生物合成，从而产生特定和可分离的生物学作用。实际上， 观察到的发育表型是可分离的。 UV1细胞坏死是由 补充烟酰胺，而突变体的性腺发育延迟被救出 通过补充烟酸。我们将确定烟酰胺的扰动是否扰动， 烟酸或NAD+水平是每种表型的原因及其在 使用药理学和遗传操作的寿命控制。我假设这一点 NAD+和烟酰胺水平的烟酰胺酶调节可能会影响NAD+的活性 消耗酶，可介导生物学作用。我们将通过 研究途径对SIR-2.1 NAD+消费者的影响，该途径调节寿命 秀丽隐杆线虫的压力抗性，并通过识别介导的NAD+消费者 发展表型。最后，我们发现了PNC-1的推定分泌的同工型， 暗示了NAD+挽救途径的细胞外作用。这个发现很有趣 最新证据证明了第一种酶在NAD+打捞途径中的全身作用的证据 哺乳动物生理学。我们将使用转基因方法来确定是否存在 多细胞中NAD+生物合成酶的进化保守的细胞外功能 有机体。这项工作将有助于阐明器官的分子机制 由NAD+前体缺乏症和人类代谢引起的病理 并将阐明Sirtuins促进寿命促进的关键方面。