Islet Endothelial Dysfunction in Diabetes

糖尿病中的胰岛内皮功能障碍

• 批准号: 9237578
• 负责人: REBECCA LUCY HULL-MEICHLE
• 金额: $ 32.96万
• 依托单位: SEATTLE INST FOR BIOMEDICAL/CLINICAL RES
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-20 至 2020-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9237578
• 关键词: ADAMTS; Adult; Affect; Animal Model; Area; Atherosclerosis; Basement membrane; Beta Cell; CD44 gene; Cell Surface Receptors; Cell Survival; Cell physiology; Cessation of life; Cultured Cells; Data; Deposition; Development; Diabetes Mellitus; Diabetic mouse; Disease; Disease Progression; Elements; Endothelial Cells; Enzymes; Extracellular Matrix; Family member; Functional disorder; Funding; Glucose; Goals; Human; Hyaluronan; Hyaluronidase; Hyperglycemia; Impairment; In Vitro; Insulin; Integrin alpha6; Intervention; Islets of Langerhans; Knock-out; Knockout Mice; Knowledge; Laminin; Laminin Receptor; Lesion; Light; Malignant Neoplasms; Matrix Metalloproteinases; Measures; Modeling; Non-Insulin-Dependent Diabetes Mellitus; PTK2 gene; Pathogenesis; Patients; Population; Production; Proteins; Pulmonary Fibrosis; Rattus; Receptor Signaling; Role; Secretory Cell; Signal Transduction; Source; TLR2 gene; Testing; Time; Toll-like receptors; United States; Up-Regulation; Viral; Work; db/db mouse; diabetic; endothelial dysfunction; improved; in vitro Model; in vivo; islet; knock-down; non-diabetic; novel; overexpression; prevent; public health relevance; restoration; transcription factor; transcriptome sequencing

ABSTRACT Type 2 diabetes affects 9% of the United States population. Impairments in β-cell secretory function and survival are critical for the development of hyperglycemia. The mechanisms underlying β-cell dysfunction and death remain incompletely understood. Improving our knowledge of these is critical for the development of better therapies for this debilitating disease. The islet extracellular matrix (ECM), synthesized predominantly by islet endothelial cells, is a critical source of signals that impinge on the β-cell; ECM components laminin and hyaluronan normally enhance insulin release and/or β-cell survival. Our preliminary data in islets from human type 2 diabetes and animal models show for the first time that laminin production is decreased, hyaluronan is disrupted/fragmented, and expression of enzymes that can degrade or destabilize laminin and hyaluronan is increased. Our preliminary data also show these findings can be reproduced by culturing primary islet endothelial cells in high glucose. Further, we can reproduce β-cell dysfunction by culturing β-cells on this “diabetic” ECM or culturing them under conditions of laminin α4-deficiency or hyaluronan fragmentation. Thus, we hypothesize that in type 2 diabetes, reduced laminin production and/or signaling and increased hyaluronan fragmentation in islet endothelial-derived ECM impairs islet β-cell secretory function and survival. Our studies will encompass the following three specific aims: Specific Aim 1: To determine whether overexpression/inhibition of laminin α4 signaling improves/impairs insulin release. We will use viral overexpression to determine if restoration of normal laminin α4 levels in ECM from “diabetic” islet endothelial cells improves insulin release and/or β-cell survival in vitro. We will also knock out the laminin receptor subunit integrin α6 in β cells of adult, non-diabetic mice and assess insulin release in vivo. Specific Aim 2: To determine the mechanism(s) by which hyaluronan fragmentation in the islet ECM contributes to impaired insulin release and β-cell survival. Fragmented hyaluronan has been shown, in non- islet cells, to be proinflammatory, activating toll-like receptors (TLR) and NFκB. Here, we will determine if fragmented hyaluronan in islet ECM impairs β-cell function and survival via TLR2/4 and NFκB activation. Specific Aim 3. To determine whether upregulation of enzymes that destabilize hyaluronan (ADAMTSs) and degrade laminin (MMPs) precedes the onset of diabetes. Using RNA-Seq, we will determine if increases in islet endothelial expression of ADAMTS and MMP family members precede diabetes and/or increase with diabetes duration in UCD-T2DM rats and are increased in T2D human islets. We will validate observed changes at the protein and activity levels, and modulate expression of these enzymes in islet endothelial-derived ECM to evaluate their effects on insulin release and β-cell survival.

抽象的 2型糖尿病会影响美国9％的人口。 β细胞秘书功能和生存的障碍对于高血糖的发展至关重要。 β细胞功能障碍和死亡的基础机制尚未完全理解。提高我们对这些知识对于这种使人衰弱的疾病的更好疗法至关重要。胰岛细胞外基质（ECM）主要由胰岛内皮细胞合成，是影响β细胞上的信号的关键来源。 ECM成分层粘连蛋白和Hydouronan通常会增强胰岛素释放和/或β细胞存活。我们在人类2型糖尿病和动物模型中的胰岛中的初步数据首次显示层粘连蛋白的产生减少，Hydrouronan是残疾/碎片的，并且可以降解或破坏层层层蛋白和Hydouronan的酶的表达。我们的初步数据还表明，这些发现可以通过在高葡萄糖中培养原代胰岛内皮细胞来繁殖。此外，我们可以通过在层粘连蛋白α4缺乏症或氢龙片段的条件下培养β细胞来再现β细胞功能障碍，或在此“糖尿病” ECM上培养β细胞。这就是我们假设在2型糖尿病中，层层粘连蛋白的产生和/或信号传导减少，以及在胰岛内皮衍生的ECM中增加的氢龙片段化损害了胰岛β细胞分泌功能和存活率。我们的研究将涵盖以下三个特定目的：具体目标1：确定层粘连蛋白α4信号传导的过表达/抑制是否会改善/损害胰岛素释放。我们将使用病毒过表达来确定从“糖尿病”胰岛内皮细胞中ECM中正常层粘连蛋白α4水平的恢复是否会改善胰岛素释放和/或β细胞在体外的释放。我们还将在成年，非糖尿病小鼠的β细胞中淘汰层粘连蛋白受体亚基整联蛋白α6和在体内评估胰岛素释放。具体目的2：确定胰岛ECM中透明质酸碎片的机制有助于受损的胰岛素释放和β细胞存活。在非 - 胰岛细胞，是促炎，激活Toll样受体（TLR）和NFκB。在这里，我们将确定胰岛ECM中的透明质酸是否会损害通过TLR2/4和NFκB激活的β细胞功能和存活。具体目的3。确定上调的酶是否破坏透明质酸（ADAMTSS）和降解层粘连蛋白（MMP）是否在糖尿病的发作之前。使用RNA-Seq，我们将确定ADAMT和MMP家族成员的胰岛内皮表达的增加和/或随着UCD-T2DM大鼠的糖尿病持续时间的增加，并且在T2D人类胰岛中增加。我们将验证观察到的蛋白质和活性水平上的变化，并调节这些酶在胰岛内皮衍生的ECM中的表达，以评估其对胰岛素释放和β细胞存活的影响。