The Role of IGRP in the Pathogenesis of Type 1 Diabetes

IGRP 在 1 型糖尿病发病机制中的作用

• 批准号: 7138189
• 负责人: Richard M O'Brien
• 金额: $ 42.5万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7138189
• 关键词: NOD mouse; autoantigens; disease /disorder model; disease /disorder prevention /control; enzyme activity; gene expression; genetically modified animals; glucose 6 phosphatase; glucose metabolism; insulin; insulin dependent diabetes mellitus; laboratory mouse; pancreatic islet function; pathologic process; protein metabolism; protein structure function

DESCRIPTION (provided by applicant): The islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP) is approximately 50% identical at the amino acid level to the glucose-6-phosphatase catalytic subunit and has recently been identified as a major autoantigen in the mouse Non-Obese Diabetic (NOD) model of type 1 diabetes. In Aim 1 we propose cross- breeding NOD mice and IGRP knockout mice to determine whether the absence of the IGRP gene in the NOD background is sufficient to prevent the onset of type 1 diabetes. If diabetes is prevented, we will perform (i) a detailed analysis of immune system function in the NOD/LtJ IGRP-/- mice to evaluate whether IGRP reactive T-cells persist in these animals and the impact on the autoimmune response directed at other islet autoantigens (ii) gene rescue experiments to determine whether re-introduction of IGRP as a BAG or cDNA restores diabetes susceptibility; only the former will be spliced and preliminary data suggest that differential splicing of IGRP RNA in thymus and islets may explain how IGRP escapes central tolerance. Alternatively, if diabetes is not prevented, we will (iii) perform a detailed analysis of cellular and humoral autoreactivity targeted at IGRP and other islet autoantigens, especially insulin and (iv) generate combined NOD/LtJ IGRP-/- and insulin I -/- mice to determine whether the absence of IGRP expression combined with a reduction in insulin expression is now sufficient to prevent the development of diabetes. Preliminary data show that deletion of the IGRP gene in mice only results in mild hypoglycemia. In Aim 2 we propose investigating the physiological basis for this observation. Since IGRP catalyzes glucose-6-phosphate hydrolysis and is expressed exclusively in pancreatic islet beta cells, we hypothesize that IGRP deletion alters the Km of glucose-stimulated insulin secretion. Therefore, oral glucose tolerance tests and hyperglycemic clamps will be used to compare insulin secretion in IGRP knockout mice and wild type littermates in vivo. In addition, insulin secretion from wild type and IGRP knockout mouse perfused pancreata will be compared in situ. Finally, insulin secretion from isolated wild type and IGRP knockout mouse islets will be compared in vitro. Relevance: A protein called IGRP has been implicated in the development of type 1 diabetes. This project will assess whether the absence of IGRP in mice is sufficient to preven the onset of diabetes.

描述（由申请人提供）：胰岛特异性葡萄糖-6-磷酸酶催化亚基相关蛋白（IGRP）在氨基酸水平上与葡萄糖-6-磷酸酶催化亚基相同，最近已被鉴定为小鼠非Obese Diabete（NOD）的主要自动抗原（NOD）。在AIM 1中，我们提出了交叉育种小鼠和IGRP敲除小鼠，以确定在点头背景中不存在IGRP基因是否足以防止1型糖尿病的发作。 If diabetes is prevented, we will perform (i) a detailed analysis of immune system function in the NOD/LtJ IGRP-/- mice to evaluate whether IGRP reactive T-cells persist in these animals and the impact on the autoimmune response directed at other islet autoantigens (ii) gene rescue experiments to determine whether re-introduction of IGRP as a BAG or cDNA restores diabetes susceptibility;只有前者才会被剪接，并且初步数据表明，胸腺和小岛中IGRP RNA的差异剪接可以解释IGRP如何逃脱中心耐受性。或者，如果不预防糖尿病，我们（iii）将对针对IGRP和其他胰岛自身抗原的细胞和体液自动反应性进行详细分析，尤其是胰岛素和（iv），结合了点头/ltj IGRP - / - / - / - 和胰岛素I - / - / - 胰岛素I-/ - / - 胰岛素I-/ - /iS grouct的表达是否不足，是否构成了IS REDINCE in in REDINCE的组合，以构建IS REDINCER IS ADRINCE ADRINCE ADINCIN IS ADRINCE ADRINCE INCININ SIRNINC ARDINCIN INCORINING IS ADRINCIN构成。 糖尿病。初步数据表明，小鼠IGRP基因的缺失仅导致轻度低血糖。在AIM 2中，我们建议研究该观察结果的生理基础。由于IGRP催化葡萄糖-6-磷酸水解并仅在胰岛胰岛β细胞中表达，因此我们假设IGRP缺失会改变葡萄糖刺激的胰岛素分泌的KM。因此，将使用口服葡萄糖耐量测试和高血糖夹来比较体内IGRP基因敲除小鼠和野生型同窝仔的胰岛素分泌。此外，将在原位比较野生型和IGRP敲除小鼠灌注胰腺的胰岛素分泌。最后，将在体外比较分离的野生型和IGRP敲除小鼠胰岛的胰岛素分泌。相关性：一种称为IGRP的蛋白质与1型糖尿病的发展有关。该项目将评估小鼠缺乏IGRP是否足以使糖尿病发作。