Calcium and the physiology of diabetes

钙与糖尿病的生理学

• 批准号: 9923637
• 负责人: ANDREW Robert MARKS
• 金额: $ 40.5万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-05-01 至 2023-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9923637
• 关键词: Address; Beta Cell; Biochemical; Biophysics; Calcium; Catecholaminergic Polymorphic Ventricular Tachycardia; Cell membrane; Clinical; Clinical Trials; DNA Sequence Alteration; Diabetes Mellitus; Drug Targeting; Endoplasmic Reticulum; Exercise; Exhibits; Extravasation; Family; Functional disorder; Genetic; Glucose; Glucose Intolerance; Glucose tolerance test; Goals; Health; Heart failure; Human; ITPR1 gene; Image; Impaired cognition; Impairment; In Vitro; Inherited; Inositol; Insulin; Ion Channel; Islets of Langerhans; Knock-in Mouse; Laboratories; Lead; Life; Link; Mediating; Mediator of activation protein; Metabolic; Mitochondria; Modeling; Molecular; Muscle Contraction; Muscular Dystrophies; Mutation; Nerve Degeneration; Non-Insulin-Dependent Diabetes Mellitus; Oral; Organ; Oxides; Pathologic; Patients; Peptide Hydrolases; Pharmaceutical Preparations; Pharmacological Treatment; Pharmacology; Phosphorylation; Physiology; Play; Post-Translational Protein Processing; Prevalence; Production; Regulation; Research; Resolution; Role; RyR1; RyR2; Ryanodine Receptor Calcium Release Channel; Ryanodine Receptors; Serum; Signal Transduction; Stress; Structure; Structure of beta Cell of islet; Sudden Death; Tacrolimus Binding Protein 1A; Testing; Therapeutic; Time; United States; base; blood glucose regulation; cell type; dalton; design; endoplasmic reticulum stress; glucose metabolism; healthy volunteer; human model; impaired glucose tolerance; improved; in vivo; insulin secretion; member; mitochondrial dysfunction; molecular mass; mouse model; mutant; new therapeutic target; novel; oxidation; pancreas development; prevent; rare genetic disorder; receptor; response; side effect; skeletal muscle weakness; small molecule; sudden cardiac death; translational impact; virtual; voltage

Type 2 diabetes mellitus (T2DM) is a major health concern worldwide, and the prevalence is increasing. Current therapeutics have potentially life-threatening side-effects. A better understanding of the molecular mechanisms underlying T2DM could lead to improved therapy. Calcium (Ca2+) plays a key role in the insulin secretion from pancreatic β cells in the islets of Langerhans. This project focuses on elucidating novel mechanisms underlying altered Ca2+ regulation that contribute to impaired insulin secretion. We show that in a rare genetic disorder intracellular Ca2+ leak via mutant type two ryanodine receptor/calcium release channels (RyR2) in pancreatic β cells is associated with glucose intolerance and decreased insulin secretion. The goal of this project is to use several murine models of T2DM to determine whether the observation that impaired insulin secretion is linked to RyR2-mediated intracellular Ca2+ leak is a generalized phenomenon in diverse models of T2DM. The approach will focus on examining the function of RyR2, a Ca2+ release channel located on the endoplasmic reticulum (ER) of many cell types including pancreatic β cells, in insulin release using biochemical, biophysical and metabolic tests. RyR2 can become leaky either due to genetic mutations or post-translational modifications (chiefly oxidation, nitrosylation and phosphorylation) all of which can impair stable closing of the channel resulting in pathological intracellular Ca2+ leak. The goal is to test the hypothesis that ER Ca2+ “leak” via RyR2 contributes to impaired insulin secretion in T2DM. The rationale is based on our recent finding that patients with leaky mutant RyR2 channels and an inherited form of exercise-induced sudden death (catecholaminergic polymorphic ventricular tachycardia, CPVT) have abnormal glucose tolerance tests (GTT) and reduced insulin levels. Knock-in mice developed in the applicant’s laboratory harboring these CPVT RyR2 mutations have ER Ca2+ leak, abnormal GTT and reduced insulin levels, just like CPVT patients. The aims are: 1 Determine how leaky RyR2 channels cause mitochondrial dysfunction, and reduced insulin release.; 2) Does RyR2 channel dysfunction contribute to impaired insulin secretion in murine models of T2DM? Furthermore we will assess whether pharmacologic treatment with a new class of rycal drugs that fix leaky RyR2 channels, or genetic treatment that fixes leaky RyR2 channels, improves Ca2+ signaling, and insulin secretion in diverse models of T2DM? The goal of the project will be to provide mechanistic links between ER Ca2+ leak, ER stress, mitochondrial dysfunction, reduced insulin secretion and glucose intolerance, and has significant translational implications as leaky RyR2 may represent a novel therapeutic target for the treatment of T2DM.

2型糖尿病（T2 DM）是世界范围内的主要健康问题，并且患病率正在增加。 目前的治疗方法具有潜在的危及生命的副作用。更好地理解分子 T2 DM的潜在机制可能导致治疗的改善。钙离子（Ca 2+）在 胰岛β细胞分泌胰岛素。该项目的重点是阐明 Ca 2+调节改变导致胰岛素分泌受损的新机制。我们表明 在一种罕见遗传性疾病中，细胞内Ca 2+通过突变型2型兰尼碱受体/钙 胰腺β细胞中的释放通道（RyR 2）与葡萄糖耐受不良和胰岛素分泌减少有关 分泌物本项目的目的是使用几种T2 DM小鼠模型来确定T2 DM是否与糖尿病相关。 观察到胰岛素分泌受损与RyR 2介导的细胞内Ca 2+渗漏有关， 在不同的T2 DM模型中的普遍现象。该方法将侧重于审查 RyR 2是位于许多细胞类型的内质网（ER）上的Ca 2+释放通道，包括 使用生物化学、生物物理学和代谢测试，研究胰腺β细胞在胰岛素释放中的作用。RyR 2可以成为 由于基因突变或翻译后修饰（主要是氧化，亚硝基化和 所有这些都可以损害通道的稳定关闭，导致病理性细胞内 Ca 2+渗漏。目的是检验ER Ca 2+通过RyR 2“泄漏”导致胰岛素受损的假设。 T2 DM的分泌。其基本原理是基于我们最近的发现， 通道和运动引起的猝死的遗传形式（儿茶酚胺能多态性 室性心动过速，CPVT）具有异常的葡萄糖耐量试验（GTT）和降低的胰岛素水平。 在申请人的实验室中开发的携带这些CPVT RyR 2突变的敲入小鼠具有ER 与CPVT患者一样，存在Ca 2+渗漏、GTT异常和胰岛素水平降低。目标是：1确定 RyR 2通道泄漏如何导致线粒体功能障碍和胰岛素释放减少。2)并 RyR 2通道功能障碍导致T2 DM小鼠模型胰岛素分泌受损？ 此外，我们还将评估用一种新的药物治疗是否能修复渗漏， RyR 2通道，或修复RyR 2通道泄漏的遗传治疗，改善Ca 2+信号传导， 在不同的T2 DM模型中的分泌？该项目的目标将是提供机械的联系， ER Ca 2+渗漏、ER应激、线粒体功能障碍、胰岛素分泌减少和葡萄糖耐受不良，以及 具有重要的翻译意义，因为泄漏的RyR 2可能代表了一种新的治疗靶点， T2 DM的治疗