Dynamin function in pancreatic beta-cell autophagy

胰腺 β 细胞自噬中的动力功能

• 批准号: 10693338
• 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: 2022
• 资助国家: 美国
• 起止时间: 2022-08-30 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10693338
• 关键词: Acetylation; Affect; American; Animals; Autophagocytosis; Beta Cell; Binding; Biochemical; Biochemistry; Biological Assay; Cell Line; Cell physiology; Cellular biology; Chronic; Cytoprotection; Data; Defect; Development; Diabetes Mellitus; Diet; Dynamin; Dynamin 2; Dynamin III; Eating; Endocytosis; Epidemic; Failure; Fasting; Genes; Genetic; Genetic Models; Guanosine Triphosphate Phosphohydrolases; Image; Imaging Techniques; Impairment; In Vitro; Insulin; Investments; Knowledge; Lead; Lysosomes; Mediating; Membrane; Metabolic stress; Methodology; Methods; Microtubules; Modification; Molecular; Mus; Nature; Non-Insulin-Dependent Diabetes Mellitus; Organ; Pathologic; Pathway interactions; Patients; Pharmaceutical Preparations; Physiological; Play; Process; Protein Isoforms; Recurrent disease; Regulation; Role; Signal Transduction; Source; Stress; Structure of beta Cell of islet; Testing; Therapeutic; Time; Tissues; Transplantation; Transportation; Vacuole; Work; blood glucose regulation; design; diabetes pathogenesis; diabetic; feeding; genetic approach; in vivo; innovation; insight; insulin secretion; interdisciplinary approach; interest; islet; live cell imaging; mouse model; novel; novel therapeutics; pathogen; pharmacologic; preservation; prevent; response; superresolution imaging; superresolution microscopy; therapeutic target; tool; trafficking; type I and type II diabetes

PROJECT SUMMARY Diabetes affects over 30 million Americans, yet its epidemic is still rising at an alarming rate. The progressive decline of pancreatic β cell function and mass is a hallmark of diabetes, but no medications prevent this decline. Interestingly, a fasting-mimicking diet known to activate autophagy stops this decline and reverses diabetes in mice. Accordingly, recent progress has increasingly recognized autophagy as a potential therapeutic target to treat diabetes because of its role in protecting β cells against pathogens and metabolic stress. However, the basic nature of β cell autophagy remains poorly understood, particularly in the molecular process governing autophagic membrane fission. Our recent data uncover that dynamin, a subfamily of large GTPases known to regulate endocytosis and insulin secretion, directly alters β cell autophagy. Live-cell imaging suggests that dynamin molecules can translocate to autolysosomes and drive autolysosome fission. Dynamin deletion causes striking autophagy defects in β cells in vitro and in vivo. These new findings fuel tremendous interest in understanding the molecule mechanisms at play throughout the β cell autophagy cycle. We hypothesize that dynamin plays a direct and crucial role in β cell autophagy flux that has not been characterized previously. Mechanistically, we suspect that dynamin regulates β cell autophagy through regulating autolysosome fission and autophagic transport. These processes may be essential to protect β cells against chronic metabolic stress toward diabetes. To test the hypothesis, we have generated dynamin isoform-specific mouse models, which allow evaluating dynamin-regulated β cell autophagy and its protection against metabolic stress associated with diabetes. We have assembled a team with substantial expertise in β cell biology, super-resolution imaging, biochemical signaling, and diabetes. We will focus on three specific aims. First, define the role of dynamin in β cell autolysosome fission. The fission step is necessary for autolysosome-to-lysosome transformation in each autophagic cycle of β cells, but its mechanism remains poorly understood. Second, identify the role of dynamin in regulating autophagic transport via microtubule modulation. This aim may uncover a previously unappreciated pathway for dynamin to regulate autophagy in β cells. Third, examine how dynamin regulates β cell autophagic responses upon metabolic stress in vivo. Together, these studies will provide new insights into the autophagic turnover in β cells and its regulation by different dynamin isoforms. The results will advance the fundamental understanding of β cell autophagy cycles that profoundly impacts islet function and diabetes pathogenesis.

项目摘要 糖尿病影响着3000多万美国人，但其流行病仍在以惊人的速度上升。的 胰腺β细胞功能和质量的进行性下降是糖尿病的标志，但没有药物治疗 防止这种下降。有趣的是，一种已知可以激活自噬的禁食模仿饮食可以阻止这种情况。 降低并逆转小鼠的糖尿病。因此，最近的进展越来越认识到， 自噬由于其保护β细胞的作用而成为治疗糖尿病的潜在靶点 抵抗病原体和代谢压力然而，β细胞自噬的基本性质仍然很差， 理解，特别是在控制自噬膜分裂的分子过程中。我们最近 数据揭示了发动蛋白，已知调节内吞作用和胰岛素的大GTP酶的亚家族， 分泌，直接改变β细胞自噬。活细胞成像表明，发动蛋白分子可以 转移到自体溶酶体并驱动自体溶酶体分裂。发动蛋白缺失导致罢工 自噬缺陷的β细胞在体外和体内。这些新发现激发了人们对 了解在整个β细胞自噬周期中起作用的分子机制。我们 假设发动蛋白在β细胞自噬流中起着直接和关键作用， 以前的特点。从机制上讲，我们怀疑发动蛋白通过调节β细胞自噬， 调节自溶体分裂和自噬转运。这些过程对于保护 β细胞对抗慢性代谢应激对糖尿病的影响。为了验证这个假设，我们生成了 动力蛋白同种型特异性小鼠模型，其允许评估动力蛋白调节的β细胞自噬 以及其对糖尿病相关代谢应激的保护作用。我们组建了一个团队 在β细胞生物学、超分辨率成像、生化信号和糖尿病方面拥有丰富的专业知识。 我们将重点关注三个具体目标。首先，明确发动蛋白在β细胞自溶酶体分裂中的作用。 在每个自噬循环中，分裂步骤是自噬体向溶酶体转化所必需的 β细胞，但其机制仍然知之甚少。第二，确定发动蛋白的作用， 通过微管调节调节自噬转运。这一目标可能揭示了一个以前 动力蛋白调节β细胞自噬的未被重视的途径。第三，研究动力素如何 调节体内代谢应激时的β细胞自噬反应。这些研究将 为β细胞的自噬更新及其受不同发动蛋白的调控提供了新的见解 同种型。这些结果将推进对β细胞自噬周期的基本理解， 对胰岛功能和糖尿病发病机制的影响。