Uncovering Two Novel Diabetes Drug Targets in the IDG

项目摘要/摘要 世界上近10%的人患有糖尿病，这一数字预计还会增加。2型糖尿病在以下情况下发生 面对胰岛素抵抗，β细胞无法产生足够的胰岛素。目前的治疗方法是不充分的 许多患者最终会对胰岛素产生依赖。尽管我们现在有许多形式的短和长 作为胰岛素，胰岛素仍然有一个很小的治疗窗口，有很高的高血糖和 低血糖，只是剂量上有轻微的错误。因此，需要新的治疗方法。我们的长期目标是 在胰岛β细胞中寻找新的治疗靶点，以改善整体功能和存活率。在这款R03中，我们 建议研究两种IDG合格基因的β细胞特异性基因敲除小鼠。一种是内质 与内质网应激有关的网状(ER)驻留蛋白。第二种是GPCR。值得注意的是，两个ER 压力和GPCRs一直是开发糖尿病药物的肥沃土壤，因此这些研究可能 未来的治疗相关性。我们假设ER蛋白的丢失将在胰腺中触发ER应激 贝塔细胞，导致贝塔细胞死亡，而贝塔细胞中GPCR的丢失将导致葡萄糖缺陷 由于G--Q信号的减少而刺激了胰岛素的分泌。目标1：表征葡萄糖 这种内质网驻留蛋白的β细胞特异性敲除小鼠的动态平衡 蛋白质反应。由于内质网应激在其他组织中的潜在作用，我们假设这一点的丧失 β细胞中的基因会导致内质网应激和β细胞死亡，从而导致糖尿病。我们将进行葡萄糖检测 对这些小鼠进行耐受性测试，同时测量基础和刺激的血浆胰岛素水平。 我们将通过胰岛灌流来研究胰岛素的分泌。我们将使用一种新的数字聚合酶链式反应来测量β细胞质量 用免疫组织化学方法检测和检测β细胞死亡。最后，我们将测量未折叠蛋白质的标记 回应。目的2：研究具有β细胞特异性的gpcr基因敲除小鼠的葡萄糖稳态。 重点放在胰岛素分泌上。鉴于该GPC的GQ偶联以及GQ在胰岛素中的已知作用 我们推测，这些β细胞特异性基因敲除的主要缺陷将是胰岛素分泌。我们 我还会问，这种GPCR的天然配体是否可以刺激胰岛正常表达 胰岛素分泌。R03提案的预期结果将是确定以下两个新目标 糖尿病治疗的目的是改善胰岛β细胞功能。这笔赠款还将使我们能够开发 在作为IDG基因敲除小鼠集合的β细胞中研究额外的IDG基因的管道 扩展。

Project Summary/Abstract Nearly 10% of the world has diabetes and this number is projected to increase. Type 2 diabetes occurs when beta cells fail to produce sufficient insulin in the face of insulin resistance. Current therapies are inadequate and many patients eventually become insulin dependent. Though we now have many forms of short and long acting insulins, insulin still has a small therapeutic window with a high chance of hyperglycemia and hypoglycemia with just slight errors in dosing. Therefore, new therapies are needed. Our long term goal is to find new therapeutic targets in the pancreatic beta cell to improve overall function and survival. In this R03, we propose to study beta-cell specific knockout mice of the two IDG-eligible genes. One is an endoplasmic reticulum (ER) resident protein that has been linked to ER stress. The second is a GPCR. Notably, both ER stress and GPCRs have been fertile grounds for development of diabetes drugs so these studies could have future therapeutic relevance. We hypothesize that loss of the ER protein will trigger ER stress in the pancreatic beta cell, resulting in beta cell death, while loss of the GPCR in beta cells will result in defective glucose stimulated insulin secretion (GSIS) due to reduced Gq signaling. Aim 1: Characterize the glucose homeostasis of a beta cell-specific knockout mouse of this ER resident protein with a focus on the unfolded protein response. Because of a potential role in ER stress in other tissues, we hypothesize that loss of this gene in the beta cell will result in ER stress and beta cell death, resulting in diabetes. We will perform glucose tolerance testing of these mice with concomitant measurement of basal and stimulated plasma insulin levels. We will study insulin secretion by islet perifusion. We will measure beta cell mass using a novel digital PCR assay and beta cell death using immunostaining. Finally, we will measure markers of the unfolded protein response. Aim 2: Characterize the glucose homeostasis of a beta cell-specific GPCR knockout mouse with a focus on insulin secretion. Given the Gq coupling of this GPCR and the known role of Gq in insulin secretion, we hypothesize the major defect in these beta cell specific knockouts will be in insulin secretion. We will also ask if a natural ligand of this GPCR, which appears to be normally expressed in the islet, can stimulate insulin secretion. The expected outcomes of this R03 proposal will be the identification of two new targets for diabetes therapeutics aimed at improving pancreatic beta cell function. This grant will also allow us to develop a pipeline to study additional IDG genes in vivo in the beta cell as the collection of IDG knockout mice expands.