Proinsulin Trafficking for Insulin Biosynthesis

用于胰岛素生物合成的胰岛素原贩运

• 批准号: 10339422
• 负责人: PETER ARVAN
• 金额: $ 50.78万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-09-01 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10339422
• 关键词: Anabolism; Animals; Beta Cell; Biological; Biological Assay; Blood Circulation; Blood Glucose; Cell Line; Cells; Code; Complex; Coupled; Cysteine; Data; Development; Diabetes Mellitus; Disease; Dissection; Disulfides; Dominant-Negative Mutation; Endoplasmic Reticulum; Environment; Failure; Functional disorder; Future; Gene Mutation; Genetic Predisposition to Disease; Grant; Heterozygote; Hormones; Human; INS gene; Individual; Insulin; Islets of Langerhans; Knock-in; Link; Maps; Metabolic; Modeling; Molecular; Mus; Mutant Strains Mice; Mutation; Non-Insulin-Dependent Diabetes Mellitus; Obesity; Pathway interactions; Patients; Phenotype; Physiological; Population; Predisposition; Process; Proinsulin; Protein Precursors; Rodent; Secretory Vesicles; Series; Structure of beta Cell of islet; Testing; Translations; Variant; Vertebral column; Western Blotting; Work; Youth; design; diabetogenic; dimer; disulfide bond; endoplasmic reticulum stress; experimental study; genetic approach; in vivo; insulin granule; insulin secretion; islet; misfolded protein; mutant; oxidation; preproinsulin; prevent; protein complex; rare condition; response; tool; trafficking

Pancreatic ß-cells store insulin and release it in response to an elevation of blood glucose. Additionally, with each meal, healthy ß-cells synthesize new insulin to replace what they have lost. The synthesis pathway begins with introducing into the endoplasmic reticulum (ER) on average ~6,000 new proinsulin molecules every second per ß-cell. Under normal conditions, these molecules must fold their insulin moiety to the native state, including the formation of 3 evolutionarily conserved disulfide bonds. However, we have now definitively identified proinsulin misfolded states that occur in the ER of human islets, rodent islets, or ß-cell lines, and get worse (more abundant) with perturbations of the ER folding environment. We believe that this is an important contributor to abnormally increased ß-cell ER stress – and it is even worse in the disease of Mutant INS-gene induced Diabetes of Youth (MIDY) – caused by any one of >30 heterozygous (dominant-negative) INS gene coding sequence mutations. A portion of the work in the current proposal will focus on MIDY models, but we also present important new data highlighting the formation of misfolded protein complexes containing proinsulin that are especially abundant in islet ß-cells without INS mutation, preceding the onset of type 2 diabetes (T2D). In our first Aim, we will further analyze the ER environment and diabetogenic conditions promoting the formation of misfolded complexes of proinsulin, using molecular, cellular, and physiological tools. In our second Aim, we propose to understand more about the molecular mechanism of misfolding by using various MIDY models, and particularly, we propose experiments that will allow us to determine how much misfolded proinsulin must accumulate in order to trigger diabetes. Finally, in our third Aim, we propose a strategy to limit proinsulin misfolding with the intent to ameliorate, delay, or prevent diabetes.

胰腺β细胞储存胰岛素并在血糖升高时释放胰岛素。此外，与 每顿饭，健康的β细胞都会合成新的胰岛素来补充它们失去的胰岛素。合成途径开始 平均每秒约有 6,000 个新胰岛素原分子引入内质网 (ER) 每个 ß 细胞。在正常条件下，这些分子必须将其胰岛素部分折叠成天然状态，包括 形成3个进化上保守的二硫键。然而，我们现在已经确定 胰岛素原错误折叠状态发生在人类胰岛、啮齿动物胰岛或 β 细胞系的 ER 中，并且会变得更糟（更多 丰富）与 ER 折叠环境的扰动。我们相信这是一个重要的贡献者 β 细胞内质网应激异常增加——在突变 INS 基因诱发的糖尿病中情况更为严重 青春期 (MIDY) – 由 >30 个杂合（显性阴性）INS 基因编码序列中的任何一个引起 突变。当前提案中的部分工作将集中在 MIDY 模型上，但我们也提出了重要的 新数据强调了含有胰岛素原的错误折叠蛋白质复合物的形成，该复合物特别是 在 2 型糖尿病 (T2D) 发病之前，在没有 INS 突变的胰岛 ß 细胞中大量存在。在我们的第一个 目的，我们将进一步分析促进形成的内质网环境和糖尿病发生条件 使用分子、细胞和生理工具研究错误折叠的胰岛素原复合物。在我们的第二个目标中，我们 建议通过使用各种 MIDY 模型来更多地了解错误折叠的分子机制，以及 特别是，我们提出了实验，使我们能够确定有多少错误折叠的胰岛素原必须 积累以引发糖尿病。最后，在我们的第三个目标中，我们提出了限制胰岛素原的策略 错误折叠的目的是改善、延迟或预防糖尿病。