ArpC3-mediated actin remodeling in insulin granule exocytosis and diabetes

ArpC3 介导的肌动蛋白重塑在胰岛素颗粒胞吐作用和糖尿病中的作用

• 批准号: 10583734
• 负责人: Xuelin Lou
• 金额: $ 39万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-01-01 至 2026-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10583734
• 关键词: Ablation; Actins; Acute; Address; Adult; Animals; Automobile Driving; Beta Cell; Biological Assay; Cell physiology; Cellular biology; Complex; Cytoplasmic Granules; Data; Diabetes Mellitus; Docking; Dynamin; Exocytosis; F-Actin; Functional disorder; Genes; Genetic; Genetic Models; Genetic study; Glucose; Human; Image; Imaging Techniques; Impairment; In Vitro; Insulin; Integrins; Internet; Investments; Knowledge; Mediating; Membrane; Metabolic; Microfilaments; Microscopy; Molecular; Mus; Nanostructures; Non-Insulin-Dependent Diabetes Mellitus; Patients; Plasma; Play; Polymers; Process; Regulation; Reporting; Research; Research Personnel; Resolution; Role; Signal Pathway; Signal Transduction; Structure; Testing; Vesicle; Work; beta Actin; blood glucose regulation; cell cortex; cellular imaging; clinically relevant; confocal imaging; diabetes pathogenesis; in vivo; insight; insulin granule; insulin regulation; insulin secretion; islet; live cell imaging; mouse model; nano; nanoscale; novel; novel therapeutics; polymerization; preservation; prevent; recruit; superresolution imaging; superresolution microscopy; tool; trafficking

PROJECT SUMMARY Insulin secretion deficiency is a hallmark of diabetes. In this process, the cortical actin of β cells has recently been recognized as a critical player contributing to diabetes pathogenesis. β cells from type-2 diabetes (T2D) patients show significant signaling alteration associated with cortical actin remodeling, and restoring such abnormality rescues insulin secretion to normal levels. Cortical actin is thought initially as a simple barrier to prevent insulin secretion, but recent studies challenge this view and imply an active role. Mounting evidence further indicates that cortical actin is a converging point and effector of multiple metabolic signals in β cells. However, the molecule and nanostructure basis of its remodeling remains unresolved. Addressing this question becomes imperative to understanding the regulation of insulin secretion and developing new therapeutics to restore β cell function in T2D. This proposal will investigate ArpC3, a gene encoding a subunit of the Arp2/3 complex that dictates actin filament branching and cortical remodeling. Although multiple signaling pathways converge on Arp2/3, the mechanism downstream Arp2/3 activity to regulate insulin secretion remains unknown. Based on recent progress in the field and our new data on β cell imaging and functional assays, we hypothesize that ArpC3-dependent actin polymerization regulates insulin exocytosis by driving the local cortical actin disassembly-reassembly cycles. Through this remodeling, cortical actin filaments may actively coordinate the critical steps of granule trafficking and insulin secretion. We have assembled a team of investigators with expertise in diabetes, β cell biology, vesicle trafficking, and super-resolution microscopy to test this hypothesis. We will focus on three specific aims. First, determine the in vivo role of ArpC3-mediated cortical actin remodeling in insulin secretion and glucose homeostasis. We have generated a new mouse model where ArpC3 is deleted selectively in adult β cells to ablate Arp2/3 activity and cortical actin branching. Second, define ArpC3 function in cortical actin nano-remodeling and its role in insulin granule recruitment, docking, and exocytosis. Third, evaluate the role of cortical actin branching in human β cells and its dysfunction in T2D patients. The results from this work will fill a long-standing knowledge gap between cortical actin remodeling and insulin secretion, providing mechanistic insights into T2D pathogenesis induced by cortical actin dysfunction.

项目摘要 胰岛素分泌缺乏是糖尿病的标志。在此过程中，β细胞的皮质肌动蛋白最近具有 被认为是促成糖尿病发病机理的关键参与者。来自2型糖尿病的β细胞（T2D） 患者显示出与皮质肌动蛋白重塑相关的显着信号传导改变，并恢复 异常将胰岛素分泌升至正常水平。皮质肌动蛋白最初被认为是 防止胰岛素分泌，但最近的研究挑战了这一观点，暗示着积极的作用。越来越多的证据 进一步表明皮质肌动蛋白是β细胞中多个代谢信号的融合点和效应因子。 但是，其重塑的分子和纳米结构基础仍未解决。解决这个问题 必须了解对胰岛素分泌的调节并开发新的治疗剂 恢复T2D中的β细胞功能。该建议将研究ARPC3，该基因编码ARP2/3的亚基 决定肌动蛋白细丝分支和皮质重塑的复合物。虽然多个信号通路 在ARP2/3上收敛，调节胰岛素分泌的下游ARP2/3活性仍然未知。 根据该领域的最新进展以及我们有关β细胞成像和功能测定的新数据，我们假设 ARPC3依赖性肌动蛋白聚合通过驱动局部皮质肌动蛋白来调节胰岛素胞吐作用 拆卸复合周期。通过这种重塑，皮质肌动蛋白丝可以主动协调 颗粒贩运和胰岛素分泌的关键步骤。我们已经组建了一个调查员团队 糖尿病，β细胞生物学，囊泡运输和超分辨率显微镜的专业知识，以检验该假设。 我们将重点关注三个特定目标。首先，确定ARPC3介导的皮质肌动蛋白重塑的体内作用 在胰岛素分泌和葡萄糖稳态中。我们已经生成了删除ARPC3的新鼠标模型 在成年β细胞中有选择地消除ARP2/3活性和皮质肌动蛋白分支。第二，定义ARPC3功能 在皮质肌动蛋白纳米复制中，其在胰岛素颗粒募集，对接和胞吐作用中的作用。第三， 评估皮质肌动蛋白在人β细胞中的作用及其在T2D患者中的功能障碍。结果 这项工作将填补皮质肌动蛋白重塑与胰岛素分泌之间的长期知识差距 对皮质肌动蛋白功能障碍引起的T2D发病机理的机械洞察力。