The role of hyaluronan in hIAPP-induced beta cell toxicity

透明质酸在 hIAPP 诱导的 β 细胞毒性中的作用

• 批准号: 10265348
• 负责人: REBECCA LUCY HULL-MEICHLE
• 金额: --
• 依托单位: VA PUGET SOUND HEALTHCARE SYSTEM
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10265348
• 关键词: 4-methylumbelliferone; Address; Adhesions; Affect; Amyloid; Amyloid deposition; Animal Model; Beta Cell; Blood capillaries; Bone Marrow; Capillary Endothelial Cell; Caring; Cell Adhesion Molecules; Cell Death; Cell Line; Cell physiology; Cells; Chemotaxis; Data; Deposition; Disease; Endothelial Cells; Endothelium; Extracellular Matrix; Functional disorder; General Population; High Fat Diet; Human; Hyaluronan; Hyaluronidase; ITGAM gene; In Vitro; Individual; Inflammasome; Inflammatory; Insulin Resistance; Interleukin-1 beta; Interleukin-6; Intervention; Islets of Langerhans; Link; Literature; Mediating; Mediator of activation protein; Modeling; Molecular Weight; Morphology; Mus; Non-Insulin-Dependent Diabetes Mellitus; Pathologic; Patients; Peptide Conformation; Peptides; Pharmaceutical Preparations; Process; Production; Protein Isoforms; Role; Signal Transduction; System; TNF gene; Therapeutic; Time; Toxic effect; Transgenic Mice; Transgenic Organisms; Work; amyloid formation; base; cell type; clinically relevant; cytokine; cytotoxic; cytotoxicity; druggable target; hyaluronan synthase 1; in vivo; inhibitor/antagonist; islet; islet amyloid polypeptide; macrophage; migration; military veteran; monocyte; new therapeutic target; novel; preservation; prevent; promoter; recruit; response

The pathophysiology of type 2 diabetes (T2D) requires islet β-cell dysfunction in the presence of insulin resistance. Islet amyloid is a pathological feature which occurs in the vast majority of individuals with type 2 diabetes (T2D) and contributes to the β-cell dysfunction and loss that characterizes the disease. Islet amyloid arises due to aggregation of the β-cell peptide islet amyloid polypeptide (IAPP), which is deposited in the islet extracellular matrix (ECM), between β cells and endothelial cells; the latter being the major cell type of the islet capillary network. Despite decades of work in the field of islet amyloid, no studies have examined whether (i) islet amyloid is toxic to islet endothelial cells or (ii) whether islet endothelial cells contribute to the toxic effects of islet amyloid. Our preliminary data suggest that both occur, and that the ECM molecule hyaluronan (HA) produced by the islet endothelial cell is a major mediator of amyloid-induced toxicity. Specifically, we have found that islet amyloid deposition in vivo is detrimental to islet endothelial cells, while treatment of isolated primary islet endothelial cells in vitro with amyloidogenic human IAPP (hIAPP) peptide is cytotoxic and results in HA production. Our preliminary data also show that HA enhances hIAPP fibril formation in vitro, which is in line with our observation that HA deposition is also present in in vivo amyloid deposits in islets from hIAPP transgenic mice and human T2D. We and others have shown that IAPP aggregation is proinflammatory, activating macrophages, and resulting in IL-1β production. However, the mechanism by which recruitment and priming of these macrophages occurs has not been established. Based on the literature, we propose that islet endothelial- derived HA provides this missing link and mediates macrophage chemotaxis, adhesion and priming. Based on these data, we hypothesize that hIAPP aggregation induces HA production from islet endothelial cells, which exacerbates hIAPP fibril formation and cytotoxicity, and acts to recruit and prime macrophages. We will address this hypothesis in the following specific aims: Specific Aim 1: To determine the mechanism by which HA exacerbates hIAPP aggregation, and thereby β-cell toxicity, in vitro. In this aim, we will determine how HA alters hIAPP peptide conformation, increases hIAPP fibril formation and whether hIAPP fibrils formed in the presence of HA show increased β-cell cytotoxicity. Specific Aim 2: To determine whether islet endothelial cell-derived HA is necessary for migration, adhesion and priming of monocytes/macrophages under conditions of islet amyloid formation. We will determine whether HA produced by hIAPP-treated islet endothelial cells results in monocyte chemotaxis, macrophage adhesion, priming of the NLRP3 inflammasome and fragmentation of HA. We will also determine if cytokines produced by macrophages or endothelial cells in response to hIAPP treatment, are necessary for HA production, and which hyaluronan synthase isoforms contribute to this process. Specific Aim 3: To determine whether blockade of HA production or fragmentation inhibits islet amyloid deposition, and thereby its detrimental effects on β cell mass and function in vivo. hIAPP transgenic and non- transgenic mice will be treated with the HA synthesis inhibitor 4-methylumbelliferone or bred to introduce a macrophage-specific deletion of hyaluronidase 1 (to inhibit HA fragmentation). These mice will then be followed for one year. We expect that reducing HA synthesis/fragmentation will reduce islet amyloid deposition and/or its toxic and proinflammatory effects, thus preserving β-cell function and mass in vivo. These studies will provide novel data regarding the role of HA mediating β-cell cytotoxicity. These are clinically relevant studies; islet amyloid is a feature of ~90% of subjects with T2D, a disease state that disproportionately affects the veteran population, and HA represents a truly “druggable” target.!

2型糖尿病（T2D）的病理生理需要在胰岛素的存在下胰岛功能障碍 反抗。胰岛淀粉样蛋白是一种病理特征，发生在绝大多数2型的个体中 糖尿病（T2D）并导致疾病的特征β细胞功能障碍和丧失。胰岛淀粉样蛋白 由于β细胞肽淀粉样多肽（IAPP）的聚集而产生 β细胞和内皮细胞之间的细胞外基质（ECM）；后者是胰岛的主要细胞类型 毛细管网络。尽管在胰岛淀粉样蛋白领域的几十年工作，但尚未研究（i）是否研究了（i） 胰岛淀粉样蛋白对胰岛内皮细胞有毒，或（ii）胰岛内皮细胞是否有助于毒性作用 胰岛淀粉样蛋白。我们的初步数据表明两者都发生，并且ECM分子透明质酸（HA） 由胰岛内皮细胞产生的是淀粉样蛋白诱导的毒性的主要介体。 具体而言，我们发现体内胰岛淀粉样蛋白沉积对胰岛内皮细胞有害，而 用淀粉样蛋白生成的人IAPP（HIAPP）肽在体外治疗分离的原发胰岛内皮细胞的治疗 细胞毒性并导致HA产生。我们的初步数据还表明，HA增强了Hiapp Fibril的形成 体外，这与我们的观察到HA沉积在体内淀粉样蛋白沉积中也存在 来自Hiapp转基因小鼠和人类T2D的胰岛。 我们和其他人表明，IAPP聚集是促炎性的，激活巨噬细胞，并且 导致IL-1β产生。但是，招募和启动的机制 发生巨噬细胞尚未建立。基于文献，我们建议胰岛内皮 - 衍生的HA提供了这种缺失的联系，并介导巨噬细胞趋化性，粘合剂和启动。 基于这些数据，我们假设HIAPP聚集诱导HA的产量 内皮细胞加剧了Hiapp原纤维形成和细胞毒性，并作用于募集和 主要巨噬细胞。 我们将在以下具体目的中解决这一假设： 特定目的1：确定HA加剧HIAPP聚集的机制，从而确定β细胞 毒性，体外。在此目标中，我们将确定HA如何改变Hiapp Peelide构象，增加Hiapp 原纤维形成以及在HA存在下形成的Hiapp纤维是否显示出β细胞的细胞毒性增加。 特定目的2：确定胰岛内皮细胞衍生的HA是否对于迁移，粘合剂和 在胰岛淀粉样蛋白形成条件下单核细胞/巨噬细胞的启动。我们将确定是否HA 由HIAPP处理的胰岛内皮细胞产生的会导致单核细胞趋化性，巨噬细胞粘合剂， NLRP3炎性体和HA的碎片的启动。我们还将确定是否由 巨噬细胞或内皮细胞应响应HIAPP治疗，对于HA的产生是必需的，并且 透明质酸合酶同工型有助于此过程。 特定目的3：确定封锁HA产生或碎片化是否抑制胰岛淀粉样蛋白 沉积，从而对β细胞质量和体内功能的有害作用。 Hiapp转基因和非 - 转基因小鼠将用HA合成抑制剂4-甲基固体或繁殖以引入A 透明质酸酶1的巨噬细胞特异性缺失（以抑制HA破碎化）。这些老鼠将是 紧接着一年。我们预计减少HA合成/碎片将减少胰岛淀粉样蛋白沉积物 和/或其有毒和促炎作用，从而保留β细胞功能和体内质量。 这些研究将提供有关HA介导β细胞细胞毒性作用的新数据。这些都是 临床相关研究；胰岛淀粉样蛋白是约90％患有T2D的受试者的特征，这是一种疾病，表明 不成比例地影响退伍军人人口，而HA代表了一个真正的“可吸毒”目标。