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: 7791323
• 负责人: WENDY HANNA-ROSE
• 金额: $ 29.65万
• 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/7791323
• 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; Figs - dietary; 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; public health relevance; reproductive; reproductive development; response; tool

DESCRIPTION (provided by applicant): 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 the aspects of regulation of lifespan promotion by sirtuins. PUBLIC HEALTH RELEVANCE: Compromised biosynthesis of nicotinamide adenine dinucleotide (NAD+) causes multiple physiological and developmental defects in the genetically tractable model organism C. elegans and has been demonstrated to impact longevity in other model systems. Deficiency of NAD+ precursors (vitamin B3) in humans also causes pathology in multiple organ systems. We aim to use C. elegans to probe the underlying molecular and genetic mechanisms causing organ malfunction and as an animal model to investigate models of longevity control.

描述（由申请人提供）：烟酰胺腺苷二核苷酸（NAD+）前体烟酰胺和烟酸（统称称为维生素B3）的人类饮食缺乏会导致多个器官系统的严重功能障碍。此外，烟酰胺的NAD+的打捞生物合成增加可促进酵母中的寿命。然而，器官病理学基础的分子机制是神秘的，在动物模型中尚未广泛探测类似的寿命调节。无脊椎动物中NAD+生物合成的打捞途径中的第一种酶是烟酰胺酶，它将烟酰胺转化为烟酸。秀丽隐杆线虫具有三个烟酰胺酶，两个PNC-1同工型和PNC-2。 PNC-1的突变导致生殖器官的不同发育缺陷。例如，性腺发育被延迟，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的突变以组织特异性的方式呈烟酰胺和烟酸水平，这可能会影响局部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细胞坏死是通过补充烟酰胺来诱导的，而突变体的性腺发育延迟是通过补充烟酸来挽救的。我们将确定使用药理学和遗传操纵的烟酰胺，烟酸或NAD+水平的扰动是导致每种表型及其在寿命控制中的相对作用。我假设NAD+和烟酰胺水平的烟酰胺酶调节可能会影响NAD+消耗酶的活性，从而介导生物学作用。我们将通过研究途径对SIR-2.1 NAD+消费者的影响来研究这一假设，该途径调节了秀丽隐杆线虫中的寿命和抗压力性，并通过识别介导发展表型的NAD+消费者。最后，我们发现了PNC-1的假定分泌同工型，这表明NAD+救助途径的细胞外作用。鉴于最近证明了哺乳动物生理学中第一种酶在NAD+救助途径中的系统作用的最新证据，这一发现令人着迷。我们将使用转基因方法来确定多细胞生物中NAD+生物合成酶是否存在进化保守的细胞外功能。这项工作将有助于阐明由NAD+前体缺乏症和人类代谢引起的分子机制，并将阐明Sirtuins促进寿命促进的方面。公共卫生相关性：烟酰胺腺嘌呤二核苷酸（NAD+）的生物合成受损会导致遗传可触及的模型有机体秀丽隐杆线虫的多种生理和发育缺陷，并已被证明会影响其他模型系统中的寿命。人类中NAD+前体的缺乏（维生素B3）也会在多器官系统中引起病理。我们的目的是使用秀丽隐杆线虫来探测引起器官故障的基本分子和遗传机制，并作为动物模型来研究寿命控制模型。