Dynamin function in beta cell autophagy

β 细胞自噬中的动力功能

• 批准号: 10473913
• 负责人: Xuelin Lou
• 金额: $ 19.5万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-22 至 2023-03-21
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10473913
• 关键词: Acetylation; Affect; American; Autophagocytosis; Beta Cell; Binding; Biochemical; Biochemistry; Biological Assay; Blood Glucose; Cell Line; Cell physiology; Cells; Cellular biology; Chronic; Data; Defect; Development; Diabetes Mellitus; Dictyostelium discoideum dynamin A; Diet; Disease; Dynamin; Dynamin 2; Dynamin III; Eating; Endocytosis; Epidemic; Failure; Family; Fasting; Fatty acid glycerol esters; Genes; Genetic; Genetic Models; Glucose; Guanosine Triphosphate Phosphohydrolases; Image; Imaging Techniques; Impairment; Insulin; Knockout Mice; Knowledge; Lysosomes; Mammals; Mediating; Membrane; Metabolic stress; Methodology; Microscopy; Microtubules; Modeling; Modification; Molecular; Mus; Nature; Organ; Outcome; Pathologic; Pathway interactions; Pharmaceutical Preparations; Phase; Play; Process; Protein Family; Protein Isoforms; Proteins; Publishing; Recurrence; Regulation; Resolution; Role; Signal Transduction; Source; Starvation; Stress; Structure of beta Cell of islet; Testing; Therapeutic; Time; Tissues; Transplantation; Transportation; Work; conditional knockout; design; diabetes pathogenesis; diabetic; feeding; high resolution imaging; imaging genetics; improved; in vivo; innovation; insight; insulin secretion; interdisciplinary approach; interest; islet; live cell imaging; loss of function; mouse genetics; mouse model; novel; pathogen; preservation; prevent; response; therapeutic target; 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 the disease, but no medications prevent this decline. Interestingly, a fasting-mimicking diet known to activate autophagy stops this decline, and it also reverses diabetes in mice. Recent progress has increasingly recognized autophagy as a potential therapeutic target to treat diabetes because autophagy has a role in protecting β cells against pathogens and diabetic stress. However, the fundamental nature of β cell autophagy remains poorly understood, particularly in the molecular process governing autophagic membrane fission. Our recent data reveal that dynamin, a family of large GTPase proteins known to regulate endocytosis and insulin secretion, directly alters β cell autophagy. Live-cell imaging reveals that dynamin molecules translocate to autolysosomes and drive autolysosome fission. Conditional dynamin deletion causes striking autophagy defects in β cells. 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 that has not been characterized. 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. We have assembled a team with substantial expertise in β cell biology, super-resolution imaging, biochemical signaling, mouse genetic models, and diabetes to test this hypothesis. We propose three specific aims. First, we will define the role of dynamin in β cell autolysosome fission. This fission step is necessary for autolysosome-to-lysosome transformation in each autophagic cycle, but its mechanism remains poorly understood. We expect that β cells use dynamin to resolve their autolysosomes into lysosomes in autophagy. Second, we will investigate how dynamin regulates β cell microtubules to alter autophagic transport. These studies may uncover a previously unappreciated pathway for dynamin to regulate autophagy. Third, we will examine dynamin- regulated β cell autophagy in vivo. We have generated dynamin isoform-specific mouse models. These unique models make it possible to evaluate dynamin-regulated β cell autophagy in vivo and its protection against the metabolic stress of diabetes. Together, these studies will provide new insight into the molecular regulation of β cell autophagy mediated by different dynamin isoforms. Their outcomes will advance the fundamental understanding of β cell autophagy that profoundly impacts islet function and diabetes pathogenesis.

项目摘要 糖尿病会影响超过3000万美国人，但其流行病仍以惊人的速度上升。这 胰腺β细胞功能和质量的进行性下降是该疾病的标志，但没有 药物阻止这种下降。有趣的是，已知会激活自噬的禁食饮食 停止这种下降，并且还逆转了小鼠的糖尿病。最近的进步已经得到认可 自噬是治疗糖尿病的潜在治疗靶点，因为自噬在保护中起作用 β细胞针对病原体和糖尿病应激。但是，β细胞自噬的基本性质 仍然了解不足，特别是在管理自噬膜的分子过程中 裂变。我们最近的数据表明，Dynamin是一个已知调节的大型GTPase蛋白的家族 内吞作用和胰岛素分泌，直接改变β细胞自噬。活电池成像揭示了 动力蛋白分子转移到自溶解体并驱动自溶性裂变。有条件的元素 缺失会导致β细胞中引人注目的自噬缺陷。这些新发现激发了人们对 了解整个β细胞自噬周期中发挥作用的分子机制。我们 假设Dynamin在β细胞自噬中起着直接而关键的作用 特征。从机械上讲，我们怀疑动力蛋白通过调节来调节β细胞自噬 自溶性裂变和自噬运输。这些过程对于保护β细胞可能至关重要 反对慢性代谢压力。我们已经组建了一个在β细胞生物学方面具有丰富专业知识的团队， 超分辨率成像，生化信号传导，小鼠遗传模型和糖尿病来测试这一点 假设。我们提出了三个具体目标。首先，我们将定义动力蛋白在β细胞中的作用 自溶性裂变。此裂变步骤对于自身溶血体到散热体转化是必需的 每个自噬循环，但其机制仍然很少理解。我们期望β细胞使用 动力蛋白将其自溶剂溶解到自噬中的溶酶体中。第二，我们将调查如何 动力蛋白调节β细胞微管以改变自噬转运。这些研究可能会发现 以前未欣赏动力蛋白调节自噬的途径。第三，我们将检查Dynamin- 调节体内的β细胞自噬。我们已经生成了Dynamin同工型特异性小鼠模型。这些 独特的模型使得在体内评估动力蛋白调节的β细胞自噬及其ITS 防止糖尿病的代谢应激。这些研究将共同​​提供新的见解 由不同的动力蛋白同工型介导的β细胞自噬的分子调节。他们的结果 将进步对β细胞自噬的基本理解，从而深刻影响胰岛功能 和糖尿病发病机理。