Regulation of Autophagy-driven Pancreatic Beta Cell Function by Nutrient Sensor Proteins

营养传感器蛋白对自噬驱动的胰腺β细胞功能的调节

• 批准号: 10576283
• 负责人: Seokwon Jo
• 金额: $ 3.37万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-02-09 至 2025-02-08
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10576283
• 关键词: Address; Affect; Apoptosis; Autophagocytosis; Autophagosome; Beta Cell; Biological Assay; Biology; Blood Glucose; Cause of Death; Cell Survival; Cell physiology; Cells; Chronic; Communication; Complex; Cues; Data; Dedications; Development; Diabetes Mellitus; Disease; Economic Burden; Environment; Enzymes; FRAP1 gene; Failure; Functional disorder; Gene Expression; Genus Hippocampus; Glucose; Goals; Health; Homeostasis; Human; Hyperglycemia; Imaging Techniques; In Vitro; Insulin; Islets of Langerhans; Knockout Mice; Knowledge; Leadership; Life; Link; Lipids; Mentors; Metabolic; Metabolic dysfunction; Metabolism; Minnesota; Mitochondria; Modeling; Mus; Non-Insulin-Dependent Diabetes Mellitus; Nutrient; O-GlcNAc transferase; Oral; Organelles; Pathology; Pathway interactions; Patients; Phase; Phenotype; Phosphotransferases; Physiological; Physiology; Post-Translational Protein Processing; Prediabetes syndrome; Prevalence; Process; Proliferating; Property; Proteins; Public Health; Recycling; Regulation; Research; Resources; Respiration; Risk; Shapes; Signal Pathway; Signal Transduction; Stress; Structure of beta Cell of islet; TSC2 gene; Technical Expertise; Testing; Therapeutic; Training; Universities; Up-Regulation; Writing; blood glucose regulation; career; diabetic; diabetic patient; extracellular; glycosylation; improved; in vivo; inhibitor; innovation; insulin secretion; islet; mitochondrial dysfunction; mortality; mouse model; new therapeutic target; novel; peptide O-linked N-acetylglucosamine-beta-N-acetylglucosaminidase; prevent; protein expression; public health relevance; response; sensor; success; targeted treatment

PROJECT SUMMARY/ABSTRACT O-GlcNAc transferase (OGT) is a nutrient sensor protein which is highly expressed in pancreatic β-cells. This enzyme exclusively catalyzes the post-translational glycosylation of target cytosolic and nucleic proteins (O- GlcNAcylation). β-cell OGT knockout mice develop severe diabetic phenotype, suggesting that OGT is crucial in shaping glucose homeostasis. The long-term goal of this research is to understand the mechanisms of how protein O-GlcNAcylation shape β-cell health and function. Our data suggest a strong relationship between OGT and mechanistic target of Rapamycin complex 1, mTORC1, a key nutrient-sensor kinase in β-cells. While aberrant autophagy and chronic mTORC1 activation is observed in islets from human diabetic patients, the mechanisms of how these signaling pathways become dysregulated is unknown. We propose that in response to nutrient stress, protein O-GlcNAcylation directly regulates mTORC1 activity and subsequent downstream mitochondrial function through the process of autophagy. Our central hypothesis is that in nutrient stress conditions, decreased O-GlcNAcylation leads to insulin secretion deficits through hypo-activation of mTORC1 and hyper-activation of autophagy. The main objective of this proposal is to delineate the signaling between OGT and mTORC1-autophagy and their contribution to β-cell health and function. Specific Aim 1 will investigate how O-GlcNAcylation regulates mTORC1 activity and β-cell mass and function. Specific Aim 2 will test whether O- GlcNAcylation modulates autophagy in β-cells and to determine the consequences of dysregulated autophagy in organelle homeostasis. This F31 proposal is innovative because there are currently no studies linking OGT and mTORC1 crosstalk in pancreatic islets and their regulation of autophagy-dependent β-cell mass and insulin secretion. Successful completion of the proposal will reveal the mechanisms linking nutrient stress conditions such as hyper-glycemia and -lipidemia to aberrant changes in organelle dysfunction and identify specific β-cell nodes of regulation between OGT and mTORC1 signaling that can be targeted for therapeutics to prevent the development of type 2 diabetes. The proposal incorporates new and timely-needed training in conceptual knowledge in islet biology, autophagy, and mitochondria, and technical skills including perifusion based insulin secretion assay, specialize imaging techniques (TEM, confocal, live cell), and Seahorse XF mitochondrial respiration assay. Scientific communication in oral and written presentation, as well as mentoring leadership will be an integral part of training to become a successful academician. All the technical resources as well as dedicated mentors at University of Minnesota and the department of Integrative Biology and Physiology are available to assist the trainee to successfully complete his F31 proposal and to assist him achieved his career and academic goals.

项目摘要/摘要 O-GLCNAC转移酶（OGT）是一种营养传感器蛋白，在胰腺β细胞中高度表达。这 酶仅催化靶胞质和核蛋白的翻译后糖基化（o- Glcnacylation）。 β细胞OGT敲除小鼠会出现严重的糖尿病表型，这表明OGT在 塑造葡萄糖稳态。这项研究的长期目标是了解如何 蛋白O-Glcnacylation形状β细胞健康和功能。我们的数据表明OGT之间有很强的关系 Rapamycin络合物1，MTORC1的机械靶标，MTORC1是β细胞中的关键营养传感器激酶。尽管 在人类糖尿病患者的胰岛中观察到异常的自噬和慢性MTORC1激活， 这些信号通路如何失调的机制尚不清楚。我们提出了回应 为了营养应激，蛋白O-Glcnacylation直接调节MTORC1活性并随后下游 线粒体功能通过自噬过程。我们的中心假设是在营养应激中 疾病，O-Glcnacylation的降低会导致胰岛素分泌通过MTORC1的低激活来定义 和自噬过度激活。该提案的主要目的是描述OGT之间的信号 MTORC1自助噬菌及其对β细胞健康和功能的贡献。特定目标1将调查如何 O-Glcnacylation调节MTORC1活性和β细胞质量和功能。特定目标2将测试是否O- Glcnacylation在β细胞中调节自噬，并确定自噬失调的后果 在Organelle稳态中。该F31提案具有创新性，因为目前没有联系OGT的研究 胰岛中的MTORC1串扰及其对自噬依赖性β细胞质量和胰岛素的调节 分泌。该提案的成功完成将揭示与营养应力条件联系的机制 例如高血糖和血脂血症，以使细胞器功能障碍的异常变化并确定特定的β细胞 OGT和MTORC1信号之间的调节节点可以用于治疗以防止 2型糖尿病的发展。该提案在概念上结合了新的和及时需要的培训 胰岛生物学，自噬和线粒体的知识以及包括基于炎症的胰岛素在内的技术技能 分泌组件，专门化成像技术（TEM，共聚焦，活细胞）和Seahorse XF线粒体 呼吸测定。口头和书面演讲以及心理领导的科学沟通将 成为成为成功的院士的培训不可或缺的一部分。所有技术资源以及 明尼苏达大学的敬业导师和综合生物学和生理学系是 可用于协助学员成功完成他的F31提案并协助他实现自己的职业生涯 和学术目标。