Improving Proinsulin Folding to Ameliorate Type II Diabetes

改善胰岛素原折叠以改善 II 型糖尿病

基本信息

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
项目类别：
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

项目摘要

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.

项目概要糖尿病是 21 世纪增长最快的健康挑战之一，影响超过 3000 万人，其中每年 80,000 人死亡，约占美国国家 2 型糖尿病 (T2D) 的 15%。最常见的糖尿病形式，与循环胰岛素量不足有关身体对激素不敏感，维持胰岛素储存池需要合成约 6000 种胰岛素。胰岛素原 (PI) 分子/ß-细胞/秒，每个均被递送至内质网 (ER) 进行折叠。值得注意的是，我们发现 PI 进入异常状态。二硫键连接的分子间复合物，即使在健康的（人类和小鼠）胰岛中也是如此。需求增加胰岛素的产生（甚至是糖尿病前期），这些复合物急剧增加，从而限制我们展示了新的关键证据，表明这些异常折叠的 PI 复合物可以被解决我们最近阐明了识别 PI 的人类 PI 相互作用组的第一个图谱。人类胰岛中最重要的 PI 相互作用因子是 ER 伴侣 BiP，我们提出了这一点。新证据（功能获得和功能丧失）表明这种相互作用，由 BiP 共同支持伴侣，对于有效的胰岛素原折叠（并限制错误折叠）绝对是必需的，从而导致在我们的研究中，我们生成了一种新型 BiP 标记小鼠，可以用于首次确定了胰岛素生产所必需的 PI 折叠的基本步骤。 BiP 及其共伴侣 P58IPK 表达的增加可显着减少高因此，我们的发现开启了药物干预的可能性。改善伴侣依赖性 PI 折叠，这可能会减弱 T2D，因为我们开始阐明人类 PI。折叠途径，我们正在开发平行动物模型来确定 PI 如何折叠/错误折叠。建议：1）从机制上剖析 BiP 和 ER 中其他 PI 交互者如何协调成功的 PI 折叠并确定 PI 折叠的哪些步骤在 T2D 中出错 2) 确定 PI 相互作用组如何变化；在人类 T2D 中；确定 T2D 患者胰岛中改变的 PI 相互作用的功能；测量 β 细胞中高效 PI 折叠/运输的新测定法我们将整合 β 细胞的生理学研究。人类胰岛采用新颖的遗传和生化方法来全面了解 PI 折叠稳态如何影响健康和疾病中的 β 细胞功能。高影响力的想法对于 NIDDK 的使命至关重要，我们现在带来了工具、分析和方法，目前在其他地方还没有。