Coordinated functions of ER quality control mechanisms in pancreatic islet α cells

胰岛α细胞ER质量控制机制的协调功能

• 批准号: 10281849
• 负责人: Rachel Byerley Reinert
• 金额: $ 17.11万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2026-05-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10281849
• 关键词: Address; Affect; Alpha Cell; Autophagocytosis; B-Lymphocytes; Beta Cell; Biochemical; Biosensor; Blood Glucose; Cell Line; Cell Survival; Cell physiology; Cells; Cellular Morphology; Cellular biology; Communication; Complex; Data; Defect; Developmental Biology; Diabetes Mellitus; Endocrine; Endoplasmic Reticulum; Ensure; Environment; Excision; Failure; Foundations; Functional disorder; Future; Genetic; Glucagon; Homeostasis; Hormones; Human; Hyperglycemia; Hypoglycemia; Image; Impairment; In Vitro; Insulin; Insulin-Dependent Diabetes Mellitus; Islet Cell; Islets of Langerhans; K-Series Research Career Programs; Link; Maintenance; Mediating; Mentors; Michigan; Modeling; Molecular; Morphology; Mus; Organelles; Pancreas; Pathway interactions; Pharmacology; Physicians; Physiology; Production; Proteins; Qi; Quality Control; Role; Scientist; Signal Transduction; Structure of alpha Cell of islet; System; Technical Expertise; Techniques; Testing; Therapeutic; Time; Training; Transduction Gene; Universities; Virus; biological adaptation to stress; blood glucose regulation; career; cofactor; diabetes pathogenesis; glucose metabolism; in vivo; inhibitor/antagonist; insight; insulin secretion; islet; live cell imaging; metabolic phenotype; misfolded protein; mouse model; novel therapeutic intervention; peptide hormone; prevent; proglucagon; protein aggregation; protein folding; proteostasis; response; sensor; ubiquitin-protein ligase

SUMMARY A central component of diabetes pathogenesis is dysregulated secretion of insulin and glucagon from b and α cells of the endocrine pancreas. Endocrine cells rely on protein quality control (QC) systems within the endoplasmic reticulum (ER) to clear misfolded proteins, maintain ER homeostasis and ensure hormone production. Misfolded proteins are removed in part through substrate-specific clearance by Sel1L-Hrd1 ER- associated degradation (ERAD), or bulk degradation of aggregates by autophagy. Our recent study showed that ERAD and autophagy regulate different aspects of β cell biology – maintenance of β cell identity and survival, respectively. Despite their shared importance in controlling glucose homeostasis, our understanding of α cell biology lags behind that of β cells. The mechanisms regulating ER homeostasis in (and thus, synthetic capacity of) α cells remain largely unexplored. To this end, mouse models lacking Sel1L-Hrd1 ERAD or autophagy in α cells were characterized. Defective ERAD limited glucagon production and α cell mass, but did not impair systemic glucagon secretion in response to hypoglycemia. In contrast, defective autophagy in α cells disrupted ER homeostasis and impaired glucagon secretion in vivo. Intriguingly, our preliminary data points to potential crosstalk between these two QC machineries. Hence, this proposal will test the overarching hypothesis that Sel1L-Hrd1 ERAD and autophagy cooperate to ensure ER proteostasis in pancreatic α cells – which is critical for α cell identity, function and/or survival. Using a combination of in vivo and in vitro genetic and pharmacologic approaches using mouse models, cell lines, and human islets, we will test the following Aims: (1) Demonstrate the pathophysiological importance of the interplay between ERAD and autophagy in α cells, and (2) Delineate the molecular mechanism underlying the crosstalk between ERAD and autophagy in α cells. This study will provide unprecedented insights into ER QC mechanisms in α cells, which may be harnessed to identify new therapeutic approaches to address α cell dysfunction in diabetes. This undertaking will build upon Dr. Reinert’s scientific expertise in developmental biology and physiology with training in two cutting-edge cell biology fields, ERAD and autophagy, with a focus on organelle crosstalk. Moreover, this study will strengthen Dr. Reinert’s technical skills by providing training in state-of-the-art cell biology techniques, thus paving a strong foundation for her future career as a physician scientist leading an interdisciplinary team studying islet cell biology and pathophysiology. This career development award will be overseen by three outstanding scientists and mentors Drs. Ling Qi, Peter Arvan, and Jiandie Lin at the University of Michigan.

摘要 糖尿病发病机制的核心部分是b和α分泌胰岛素和胰升糖素的失调。 胰腺内分泌细胞。内分泌细胞依靠体内的蛋白质质量控制(QC)系统 内质网(ER)清除错误折叠的蛋白质，维持ER动态平衡，并确保激素 制作。错误折叠的蛋白质部分通过Sel1L-Hrd1 ER-1底物特异性清除而被移除。 联合降解(ERAD)，或通过自噬大量降解聚集体。我们最近的研究表明 ERAD和自噬调节β细胞生物学的不同方面--维持β细胞的特性和 分别是生存。尽管它们在控制血糖稳态方面都很重要，但我们的理解是 α细胞生物学的研究落后于β细胞。调节内质网稳态的机制(因此，合成的 α细胞的能力在很大程度上仍未得到开发。为此，缺乏Sel1L-Hrd1 ERAD或 检测α细胞的自噬现象。有缺陷的ERAD限制了胰高血糖素的产生和α细胞质量，但确实如此 不会因低血糖而损害全身胰高血糖素的分泌。相比之下，α中有缺陷的自噬 体内的细胞破坏了内质网的动态平衡，并损害了胰升糖素的分泌。有趣的是，我们的初步数据 指出这两台QC机器之间存在潜在的串扰。因此，这项提案将考验 最重要的假设是Sel1L-Hrd1 ERAD和自噬共同确保ER蛋白稳定 胰腺α细胞--这对α细胞的特性、功能和/或生存至关重要。使用中的组合 使用小鼠模型、细胞系和人类胰岛的体内和体外遗传和药理学方法，我们 将测试以下目标：(1)证明ERAD之间相互作用的病理生理学重要性 和α细胞中的自噬，以及(2)描绘了ERAD之间串扰的分子机制 和α细胞的自噬。这项研究将为α细胞的ER QC机制提供前所未有的见解， 这可能被利用来确定新的治疗方法来解决糖尿病患者的α细胞功能障碍。这 该项目将以莱纳特博士在发育生物学和生理学方面的科学专业知识为基础， 两个尖端细胞生物学领域的培训，ERAD和自噬，重点是细胞器串扰。 此外，这项研究将通过在最先进的细胞中提供培训来加强Reinert博士的技术技能 生物学技术，从而为她未来的职业生涯奠定了坚实的基础，成为一名内科科学家，领导着一个 研究胰岛细胞生物学和病理生理学的跨学科团队。这个职业发展奖将是 由三位杰出的科学家和导师凌琦博士、彼得·阿文博士和林健迪博士在 密歇根大学。