Improving Proinsulin Folding to Ameliorate Type II Diabetes

改善胰岛素原折叠以改善 II 型糖尿病

• 批准号: 10657292
• 负责人: PETER ARVAN
• 金额: $ 80.96万
• 依托单位: SANFORD BURNHAM PREBYS MEDICAL DISCOVERY INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-05 至 2027-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10657292
• 关键词: Affect; Animal Model; Attenuated; Beta Cell; Binding; Biochemical; Biogenesis; Biological Assay; Cell Line; Cell physiology; Cells; Cessation of life; Complex; Confocal Microscopy; Data; Development; Diabetes Mellitus; Disease; Disulfides; Endoplasmic Reticulum; Environment; Epitopes; Failure; Functional disorder; Genetic; Genetic Models; Grant; Health; Health Expenditures; Heat-Shock Proteins 70; Homeostasis; Hormones; Human; Individual; Insulin; Insulin Resistance; Intervention; Islets of Langerhans; Link; Maintenance; Maps; Measures; Mission; Modeling; Molecular; Molecular Chaperones; Molecular Weight; Mus; National Institute of Diabetes and Digestive and Kidney Diseases; Nature; Non-Insulin-Dependent Diabetes Mellitus; Oxidoreductase; Pathogenesis; Pathway interactions; Patients; Persons; Pharmaceutical Preparations; Physiological; Prediabetes syndrome; Predisposition; Production; Productivity; Proinsulin; Proteins; Reporter; Reporting; Series; Severities; Structure of beta Cell of islet; Time; Variant; anterograde transport; cofactor; crosslink; disulfide bond; functional loss; gain of function; genome wide association study; improved; islet; loss of function; monomer; mouse model; novel; pharmacologic; prevent; response; superresolution microscopy; tool; trafficking

Project Summary Diabetes is among the fastest growing health challenges of the 21st century, affecting >30 million people, with ≥80,000 deaths annually, and involving ~15% of U.S. national health expenditures. Type 2 diabetes (T2D) is the most common form of diabetes, which is linked to an insufficient amount of circulating insulin because of the body’s insensitivity to the hormone. Maintenance of the insulin storage pool requires synthesis of ~6000 proinsulin (PI) molecules/ß-cell/second, each delivered to the endoplasmic reticulum (ER) for folding. Even more molecules are needed in states of insulin resistance. Significantly, we discovered that PI enters aberrant disulfide-linked intermolecular complexes, even in healthy (human and murine) islets. Under conditions that demand increased insulin production (even prediabetes), these complexes dramatically increase, thus limiting insulin production. We show new key evidence that these aberrantly folded PI complexes can be resolved to monomeric PI within the ER. We recently elucidated the first map of the human PI interactome identifying PI folding modifiers. The most significant PI interactor in human islets is the ER chaperone BiP and we present new evidence (both gain of function, and loss of function) that this interaction, supported by BiP co- chaperones, is absolutely required for productive proinsulin folding (and limiting misfolding), leading to successful anterograde transport. For our studies we generated a novel BiP-tagged mouse that can for the first time identify fundamental steps in PI folding essential for insulin production. Moreover, we show that increased expression of BiP and its co-chaperone P58IPK dramatically reduces accumulation of the high molecular weight PI complexes. Thus, our discoveries open the possibility that pharmacologic intervention may improve chaperone-dependent PI folding, and this may attenuate T2D. As we begin to elucidate the human PI folding pathway, we are developing parallel animal models to determine how PI folds/misfolds. Here we propose to: 1) Mechanistically dissect how BiP and additional PI interactors in the ER orchestrate successful PI folding and determine which step(s) of PI folding go awry in T2D; 2) Identify how the PI interactome changes in human T2D; determine the function of altered PI interactions in islets from patients with T2D; and utilize novel assays to measure productive PI folding/trafficking in ß-cells. We will integrate physiologic studies of human islets with novel genetic and biochemical approaches to generate a comprehensive understanding of how PI folding homeostasis impacts ß-cell function in health and disease. We believe that this hypothesis is a high-impact idea essential to the mission of the NIDDK, and we now bring tools, assays, and approaches that are not currently available anywhere else.

项目摘要 糖尿病是世纪增长最快的健康挑战之一，影响超过3000万人， 每年有≥ 80，000例死亡，占美国国家卫生支出的约15%。2型糖尿病（T2 D）是 糖尿病最常见的形式，这与循环胰岛素量不足有关， 身体对荷尔蒙不敏感胰岛素储存池的维护需要合成约6000 胰岛素原（PI）分子/β-细胞/秒，每个分子被递送到内质网（ER）进行折叠。甚至 在胰岛素抵抗状态下需要更多的分子。值得注意的是，我们发现PI进入异常 二硫键连接的分子间复合物，甚至在健康的（人和鼠）胰岛。的条件下 由于需要增加胰岛素产量（甚至是糖尿病前期），这些复合物急剧增加，从而限制了 胰岛素生产。我们展示了新的关键证据，这些异常折叠的PI复合物可以被解析为 ER内的单体PI。我们最近阐明了人类PI相互作用组的第一个图谱， 折叠修饰符人类胰岛中最重要的PI相互作用是ER伴侣BiP，我们提出 新的证据（功能的获得和功能的丧失）表明，这种相互作用，由BiP共同支持， 分子伴侣是生产性胰岛素原折叠（和限制错误折叠）所绝对需要的，导致 成功顺行运输。在我们的研究中，我们产生了一种新的BiP标记的小鼠， 第一次确定PI折叠的基本步骤对胰岛素的生产至关重要。此外，我们表明， BiP及其辅助分子伴侣P58 IPK表达的增加显著降低了高浓度的 分子量PI络合物。因此，我们的发现开启了药物干预可能 改善分子伴侣依赖性PI折叠，这可以减弱T2 D。当我们开始阐明人类PI 折叠途径，我们正在开发平行的动物模型，以确定PI如何折叠/错误折叠。这里我们 建议：1）机械地剖析BiP和ER中的其他PI互动者如何协调成功的PI 折叠，并确定T2 D中PI折叠的哪些步骤出错; 2）确定PI相互作用组如何变化 在人T2 D中;确定来自T2 D患者的胰岛中改变的PI相互作用的功能;并利用 测量β-细胞中生产性PI折叠/运输的新测定法。我们将整合生理学研究， 人类胰岛与新的遗传和生物化学方法，以产生全面的了解， PI折叠稳态如何影响健康和疾病中的β细胞功能。我们认为，这一假设是一个 高影响力的想法是NIDDK的使命必不可少的，我们现在带来的工具，分析，和方法， 目前在其他任何地方都没有。