Role of Polyamines and Hypusine in Nutrient-Induced Beta-Cell Growth and Replication

多胺和马尿苷在营养诱导的 β 细胞生长和复制中的作用

• 批准号: 9981964
• 负责人: Laura C Alonso
• 金额: $ 58.67万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-05-07 至 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/9981964
• 关键词: ATF6 gene; Acute; Amino Acids; Anabolism; Arginine; Assessment tool; B Cell Proliferation; Beta Cell; Biogenic Amines; Biosensor; Cell Cycle; Cells; Cellular biology; Cessation of life; Collection; Data; Dependence; Diabetes Mellitus; Diet; Disease; Enzymes; Functional disorder; Gatekeeping; Genetic; Genetic Transcription; Genetic Translation; Glucose; Glutamine; Growth; Growth and Development function; Human; Hyperglycemia; Image; Insulin; Knockout Mice; Leucine; Link; Mediating; Messenger RNA; Metabolic; Methionine; Modeling; Modification; Molecular; Mus; Natural regeneration; Nutrient; Nutritional; Obesity; Ornithine Decarboxylase; Pathway interactions; Phase; Phenylalanine; Polyamines; Positioning Attribute; Production; Proline; Proteins; Publishing; Reagent; Ribosomes; Rodent; Role; Signal Transduction; Spermidine; Stress; Techniques; Technology; Testing; Time; Translations; base; blood glucose regulation; cell growth; conditional knockout; deoxyhypusine synthase; eIF-5A; experimental study; hypusine; in vivo; islet; mouse model; novel; obesogenic; response; small molecule; transcription factor; translation factor; virtual

This project is inspired by the premise that signals and substrates extrinsic to the β-cell trigger cell cycle entry, and that reactivation of the cell cycle in β-cells would provide the potential for restoring β-cell mass and function in diabetes. Our published and preliminary data suggest that the translation factor eIF5A functions as an acute response factor that catalyzes translation of specific mRNAs, enabling cellular replication. Strikingly, eIF5A is the only protein containing the unique, polyamine-derived amino acid hypusine, which is required for its function. Hypusine formation occurs posttranslationally and is governed by two rate-limiting enzymes, ornithine decarboxylase (ODC) and deoxyhypusine synthase (DHPS). ODC generates intracellular polyamines from arginine (and indirectly from glutamine, proline, methionine, phenylalanine, leucine), and DHPS utilizes the polyamine spermidine to form hypusine on eIF5A. Collectively, we refer to the ODC/DHPS/eIF5A proteins as belonging to the “polyamine/hypusine pathway.” Because polyamine and hypusine productions can be manipulated by diet and/or small molecules, they represent real-world targets to intervene in β-cell growth and replication. We hypothesize that the pathway that generates polyamines and hypusine links nutritional signals (amino acids, glucose) to mRNA translation to enable adaptive β-cell replication. The strength of this Multi-PI R01 application is the collaborative effort between Drs. R. Mirmira (an expert in the polyamine/hypusine pathway in β-cells) and L. Alonso (an expert in β-cell replication); our Team is uniquely positioned with the relevant expertise, novel conditional knockout mice, and mRNA translation assessment tools to test this hypothesis. We propose the following 3 aims: Aim 1: Elucidate the mechanisms by which the polyamine/hypusine pathway governs adaptive β-cell proliferation in models of obesity and hyperglycemia. Aim 2: Characterize how polyamine biosynthesis functions as a nutrient-activated gatekeeper for the proliferative signal induced by the UPR in β-cells. Aim 3: Reveal an unusual function of eIF5A as a biosensor for amino acid and polyamine supply. We will use a comprehensive toolbox of state-of-the-art imaging and cell biology techniques and novel reagents, including the only collection of ODC/DHPS/eIF5A knockout mice, to reveal a role in β-cell proliferation for an otherwise enigmatic pathway. Therefore, the primary impact of this proposal is the identification and mechanisms of the polyamine/hypusine pathway in rodent and human β-cell replication.

该项目的灵感来自这样一个前提：β 细胞的外在信号和底物触发细胞周期进入，并且 β 细胞中细胞周期的重新激活将提供恢复糖尿病中 β 细胞质量和功能的潜力。我们发表的初步数据表明，翻译因子 eIF5A 作为一种急性反应因子，催化特定 mRNA 的翻译，从而实现细胞复制。引人注目的是，eIF5A 是唯一含有独特的多胺衍生氨基酸 hypusine 的蛋白质，这是其功能所必需的。山马尿苷的形成发生在翻译后，并受到两种限速酶的控制：鸟氨酸脱羧酶 (ODC) 和脱氧山马尿苷合酶 (DHPS)。 ODC 从精氨酸（以及间接从谷氨酰胺、脯氨酸、蛋氨酸、苯丙氨酸、亮氨酸）生成细胞内多胺，而 DHPS 利用多胺亚精胺在 eIF5A 上形成高尿嘧啶。总的来说，我们将 ODC/DHPS/eIF5A 蛋白称为属于“多胺/马尿苷途径”。由于多胺和马尿苷的产生可以通过饮食和/或小分子来控制，因此它们代表了干预 β 细胞生长和复制的现实目标。我们假设产生多胺和马尿苷的途径将营养信号（氨基酸、葡萄糖）与 mRNA 翻译联系起来，从而实现适应性 β 细胞复制。该 Multi-PI R01 应用程序的优势在于 Drs. 之间的协作努力。 R. Mirmira（β 细胞多胺/马尿苷途径专家）和 L. Alonso（β 细胞复制专家）；我们的团队拥有独特的优势，拥有相关专业知识、新型条件敲除小鼠和 mRNA 翻译评估工具来检验这一假设。我们提出以下 3 个目标： 目标 1：阐明多胺/马尿苷途径在肥胖和高血糖模型中控制适应性 β 细胞增殖的机制。目标 2：表征多胺生物合成如何作为营养激活的看门人发挥作用，以控制 β 细胞中 UPR 诱导的增殖信号。目标 3：揭示 eIF5A 作为氨基酸和多胺供应生物传感器的不寻常功能。我们将使用最先进的成像和细胞生物学技术以及新型试剂的综合工具箱，包括唯一的 ODC/DHPS/eIF5A 敲除小鼠集合，来揭示一条神秘途径在 β 细胞增殖中的作用。因此，该提案的主要影响是啮齿动物和人类β细胞复制中多胺/马尿苷途径的识别和机制。