Mechanisms and Impact of Islet Vascular Inflammation in Diabetes

糖尿病胰岛血管炎症的机制和影响

• 批准号: 10589674
• 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 2026-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10589674
• 关键词: 3-Dimensional; Address; Affect; Amputation; Amyloid; Animal Model; Beta Cell; Blindness; Blood Vessels; Blood capillaries; Blood flow; Brain; C-Type Lectins; Cell Death; Cell Survival; Cell model; Cell physiology; Cells; Crossbreeding; Data; Defect; Deposition; Development; Diabetes Mellitus; Diabetic Nephropathy; Diabetic Retinopathy; End stage renal failure; Endothelial Cells; Endothelium; Extracellular Matrix; Extravasation; Failure; Family; Functional disorder; Health; Healthcare Systems; Homeostasis; Human; Hyperglycemia; Impairment; In Vitro; Inflammation; Insulin; Islet Cell; Islets of Langerhans; Knowledge; Mediating; Mediator; Microvascular Dysfunction; Modeling; Molecular; Mus; Non-Insulin-Dependent Diabetes Mellitus; Nutrient; Pancreas; Paracrine Communication; Pathogenesis; Pathology; Pathway interactions; Patients; Pericytes; Peripheral; Play; Population; Predisposition; Role; Signal Transduction; Slice; Source; Tissues; Toxic effect; Transgenic Mice; Vascular Diseases; Vascularization; Veterans; Work; cell type; cytotoxicity; endocrine pancreas development; human data; in vivo; islet; islet amyloid polypeptide; kidney fibrosis; member; neuroinflammation; novel; prevent; response; targeted treatment; transcriptome sequencing; vascular abnormality; vascular inflammation

Insufficient release of insulin from the pancreatic islet β cell is a critical defect in type 2 diabetes (T2D). Pancreatic islets are highly vascularized, and this vasculature is essential for nutrient supply to islet cells, insulin delivery to peripheral tissues and as a rich source of signals that support β-cell function. In human T2D and animal models, islet vasculopathy manifests as endothelial inflammation and capillary dilation and fragmentation. Moreover, induction of these islet vascular abnormalities in vitro is sufficient to impair insulin release and/or induce β-cell death. We have identified human islet amyloid polypeptide (hIAPP) aggregation as a mediator of islet vasculopathy. hIAPP-derived amyloid deposits accumulate in the extracellular matrix between β cells and islet capillaries in almost all patients with T2D. We now show that hIAPP aggregation results in islet endothelial cell cytotoxicity and inflammation, capillary dilation and loss. Using, RNA-Seq we identified Clec14a as a potential molecular mediator of hIAPP-induced islet endothelial damage. Clec14a is a member of the vascular C-type lectin family, whose pancreatic expression is restricted to endothelial cells. Clec14a deficiency has been shown to result in microvascular destabilization, inflammation and cell death in several tissues but has never been studied in the pancreas. We will now determine if loss of Clec14a exacerbates the islet endothelial response to hIAPP in vitro and increases susceptibility to hIAPP-induced islet vasculopathy and exacerbates β-cell dysfunction in vivo. Capillary-associated pericytes play a critical role in normal microvascular homeostasis. In several tissues, including islets, pericytes regulate capillary tone and blood flow. Pericyte coverage is also necessary for endothelial integrity, pericyte-endothelial interactions prevent endothelial inflammation and vessel leakage. This interaction, in non-islet tissues, is governed both by paracrine signals and cell-cell contact, of which Clec14a is just one mediator. Disruption of endothelial-pericyte interactions underlies the vascular instability and inflammation that drives development of diabetic retinopathy and renal fibrosis. Pericyte detachment/loss also occurs in T2D islets. However, the mechanisms that govern islet endothelial-pericyte attachment, how these are disrupted in T2D and the consequent impact on β-cell function have not been studied. This proposal will address this major knowledge gap. Our preliminary data show that hIAPP aggregation leads to islet pericyte detachment and degeneration. Our data and others’ show this includes a direct toxic effect of hIAPP on microvascular pericytes, resulting in loss of key signals that govern endothelial cell-pericyte cross-talk. This proposal will address the hypothesis that disruption of islet endothelial cell-pericyte interactions, mediated in part by Clec14a deficiency, underlies hIAPP-induced islet vasculopathy and contributes to β-cell dysfunction. We propose three aims to address this hypothesis: Aim 1. To determine whether Clec14a deficiency mediates the deleterious vascular effects of aggregated IAPP in vitro and exacerbates hIAPP-induced islet vasculopathy and β-cell dysfunction in vivo. Aim 2. To determine the role of islet endothelial cell-pericyte interactions in mediating deleterious effects of hIAPP aggregation in vitro. Aim 3. To determine the impact of aggregated hIAPP on islet pericyte function ex vivo and identify islet endothelial cell/pericyte-derived mediators of impaired insulin release and β-cell death in vitro. These novel studies will be the first to investigate Clec14a in the pancreas, and to interrogate mechanisms governing islet endothelial cell-pericyte interactions under normal conditions and following hIAPP aggregation. This work is significant as it could lead to development of new vascular-targeted therapies which could treat β- cell dysfunction and may also be relevant for the microvascular disease which affects many tissues in T2D.

胰岛 β 细胞释放胰岛素不足是 2 型糖尿病 (T2D) 的一个关键缺陷。 胰岛是高度血管化的，这种脉管系统对于胰岛细胞的营养供应至关重要， 胰岛素输送到外周组织并作为支持人类 T2D β 细胞功能的丰富信号源。 和动物模型中，胰岛血管病变表现为内皮炎症和毛细血管扩张， 此外，体外诱导这些胰岛血管异常足以损害胰岛素。 释放和/或诱导β细胞死亡。 我们已经确定人胰岛淀粉样蛋白多肽 (hIAPP) 聚集是胰岛的介质 hIAPP 衍生的淀粉样蛋白沉积物积聚在 β 细胞和胰岛之间的细胞外基质中。 我们现在证明 hIAPP 聚集导致胰岛内皮细胞。 使用 RNA-Seq，我们确定 Clec14a 具有潜在的细胞毒性和炎症、毛细血管扩张和损失。 Clec14a 是 hIAPP 诱导的胰岛内皮损伤的分子介质，是血管 C 型的成员。 凝集素家族的胰腺表达仅限于内皮细胞，已被证明存在 Clec14a 缺陷。 导致多种组织中的微血管不稳定、炎症和细胞死亡，但从未被证实 我们现在将确定 Clec14a 的缺失是否会恶化胰岛内皮细胞的反应。 hIAPP 在体外会增加对 hIAPP 诱导的胰岛血管病变的易感性并使 β 细胞恶化 体内功能失调。 毛细血管相关周细胞在多种组织的正常微血管稳态中发挥着关键作用。 包括胰岛在内，周细胞调节毛细血管张力和血流，周细胞的覆盖也是必要的。 内皮完整性、周细胞-内皮相互作用可防止内皮炎症和血管渗漏。 在非胰岛组织中，这种相互作用受到旁分泌信号和细胞间接触的控制，其中 Clec14a 只是血管不稳定的基础之一，内皮-周细胞相互作用的破坏。 以及导致糖尿病视网膜病变和肾纤维化发展的炎症。 也发生在 T2D 胰岛中，但是，控制胰岛内皮-周细胞附着的机制是如何的。 这些在 T2D 中被破坏，因此尚未研究对 β 细胞功能的影响。 我们的初步数据表明 hIAPP 聚合会导致胰岛的形成。 我们的数据和其他人的数据表明，这包括 hIAPP 的直接毒性作用。 作用于微血管周细胞，导致控制内皮细胞-周细胞串扰的关键信号丢失。 该提案将解决胰岛内皮细胞-周细胞相互作用破坏的假设， 部分由 Clec14a 缺陷介导，是 hIAPP 诱导的胰岛血管病变的基础，并有助于 我们提出了三个目标来解决这一假设： 目标 1. 确定 Clec14a 缺乏是否介导聚集的血管的有害作用 IAPP 在体外并加剧 hIAPP 诱导的胰岛血管病变和体内 β 细胞功能障碍。 目标 2. 确定胰岛内皮细胞-周细胞相互作用在介导有害影响中的作用 hIAPP 体外聚集。 目标 3. 确定聚集的 hIAPP 对离体胰岛周细胞功能的影响并识别胰岛 体外胰岛素释放受损和 β 细胞死亡的内皮细胞/周细胞衍生介质。 这些新颖的研究将首次调查胰腺中的 Clec14a，并探究其机制 在正常条件下和 hIAPP 聚集后控制胰岛内皮细胞-周细胞相互作用。 这项工作意义重大，因为它可能导致开发新的血管靶向疗法，从而治疗β- 细胞功能障碍，也可能与影响 T2D 中许多组织的微血管疾病有关。