Peptide Hormone Sorting to the Secretory/Storage Granule

肽激素分选至分泌/储存颗粒

• 批准号: 8003256
• 负责人: PETER ARVAN
• 金额: $ 2.25万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-12-23 至 2010-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8003256
• 关键词: Accounting; Adult; Affect; Alleles; Animals; Automobile Driving; Beta Cell; Biological Assay; Birth; Blood Glucose; C-Peptide; Cell Culture System; Cell Culture Techniques; Cell Death; Cell physiology; Cells; Child; Code; Color; Cytoplasmic Granules; Defect; Diabetes Mellitus; Disease; Disulfides; Dominant-Negative Mutation; Endoplasmic Reticulum; Event; Failure; Fluorescence Microscopy; Genetic; Golgi Apparatus; Grant; Heterozygote; Human; Insulin; Lead; Life; Link; Metabolism; Modeling; Molecular; Monitor; Mutation; Neonatal; Onset of illness; Oxidation-Reduction; Oxidoreductase; Pancreas; Pathway interactions; Patients; Physiological; Point Mutation; Process; Production; Proinsulin; Proteins; Reactive Oxygen Species; Reporting; Research; Risk; Secretory Vesicles; Sorting - Cell Movement; Source; Stress; System; Time; Transgenic Mice; Translations; Work; base; disulfide bond; endoplasmic reticulum stress; in vivo; insulin secretion; mouse model; mutant; neonatal diabetes mellitus; neonate; novel strategies; peptide hormone; preproinsulin; programs; promoter; public health relevance; research study; residence; sound

DESCRIPTION (provided by applicant): The peptide hormone, insulin, regulates metabolism to homeostatically maintain blood glucose levels within a narrow physiological range. In pancreatic ss-cells, insulin is made and stored at high concentration within secretory granules. Physiological stimulation of insulin secretion (multiple times per day) requires very active synthesis of new insulin to replenish secretory granule reserves. Insulin synthesis begins with translation of preproinsulin for delivery into the lumen of the endoplasmic reticulum (ER). Therein, proinsulin must properly fold, which is easier than it sounds: proinsulin is a "disulfide-challenged" protein. Moreover, when beta cells are forced to synthesize higher levels of proinsulin than they are genetically-programmed to handle, they risk further proinsulin misfolding/disulfide mispairing, which leads to secretory pathway stress. The objective of this new grant cycle is to better understand proinsulin folding and export from the ER. We hypothesize that misfolding of a subfraction of proinsulin in the ER can block insulin production derived from the other subfracton of "bystander" proinsulin molecules, backlogging the protein in the ER, and driving ER stress, beta cell failure, loss of pancreatic insulin content, and diabetes. We propose four Specific Aims: 1) To elucidate the molecular mechanism(s) by which newly-described point mutations in the coding sequence of preproinsulin lead to human diabetes in neonates and adults. 2) To characterize ss-cell ER oxidoreductases. 3) To develop a new cell culture-based system to dissect steps leading to beta cell death. 4) To develop an in vivo analysis of pancreatic insulin production in diabetes. PUBLIC HEALTH RELEVANCE: Insulin regulates metabolism to maintain normal blood glucose levels. Synthesis of new insulin begins with translation of proinsulin in the endoplasmic reticulum. In the past year, more than 20 new proinsulin mutations have been found to be associated with neonatal onset diabetes. Evidence suggests that these mutant proinsulins are made as proteins but it is not known how they cause diabetes. Each patient also havs another allele of perfectly normal proinsulin which should be more than enough proinsulin synthesis to satisfy the body's need for insulin. This new grant cycle proposes experiments to better understand proinsulin folding and export in order to see how misfolding of a subfraction of proinsulin in the ER can block insulin production derived from "bystander" proinsulin molecules, causing ER stress, beta cell failure, and diabetes.

描述（由申请人提供）：肽激素胰岛素调节新陈代谢以将血糖水平稳态维持在狭窄的生理范围内。在胰腺 ss 细胞中，胰岛素被产生并以高浓度储存在分泌颗粒中。胰岛素分泌的生理刺激（每天多次）需要非常活跃的新胰岛素合成以补充分泌颗粒储备。胰岛素合成始于前胰岛素原的翻译，并输送至内质网 (ER) 的腔内。其中，胰岛素原必须正确折叠，这比听起来容易：胰岛素原是一种“二硫键挑战”的蛋白质。此外，当β细胞被迫合成高于其基因编程处理水平的胰岛素原时，它们面临进一步胰岛素原错误折叠/二硫键错配的风险，从而导致分泌途径应激。这个新资助周期的目标是更好地了解胰岛素原折叠和从 ER 的输出。我们假设，内质网中胰岛素原的一个亚组分的错误折叠可以阻止来自“旁观者”胰岛素原分子的另一个亚组分的胰岛素产生，使蛋白质积压在内质网中，并导致内质网应激、β细胞衰竭、胰腺胰岛素含量减少和糖尿病。我们提出了四个具体目标：1）阐明前胰岛素原编码序列中新描述的点突变导致新生儿和成人糖尿病的分子机制。 2) 表征单链细胞内质网氧化还原酶。 3）开发一种新的基于细胞培养的系统来剖析导致β细胞死亡的步骤。 4) 开发糖尿病中胰腺胰岛素产生的体内分析。公共健康相关性：胰岛素调节新陈代谢以维持正常的血糖水平。新胰岛素的合成始于胰岛素原在内质网中的翻译。去年，超过20种新的胰岛素原突变被发现与新生儿发病的糖尿病有关。有证据表明这些突变的胰岛素原是由蛋白质制成的，但尚不清楚它们如何导致糖尿病。每个患者还具有完全正常的胰岛素原的另一个等位基因，其应该足以合成足够的胰岛素原以满足身体对胰岛素的需要。这个新的资助周期提出了实验，以更好地了解胰岛素原折叠和输出，以便了解内质网中胰岛素原亚组分的错误折叠如何阻止“旁观者”胰岛素原分子产生胰岛素，从而导致内质网应激、β细胞衰竭和糖尿病。