Functional and molecular characterization of the human islet interferon alpha response

项目摘要/摘要 在过去的几年里，美国人口中的糖尿病发病率一直在迅速增加 几十年。1型糖尿病是β细胞死亡的结果，也就是胰腺中产生胰岛素的细胞的凋亡。 然而，我们目前对启动过程中涉及的分子事件的理解是有限的。 胰腺β细胞凋亡和β细胞异质性在1型糖尿病发病机制中的作用。 干扰素-α介导的信号转导是1型糖尿病病理生理过程中的重要组成部分。儿童 1型糖尿病的遗传风险在血细胞中有I型干扰素诱导的转录信号， 先于自身抗体的出现。I型干扰素也在1型糖尿病患者的胰岛中表达 1糖尿病和来自最近发病的1型糖尿病的活体捐赠者的激光捕获的胰岛显示 干扰素刺激的基因。干扰素-α诱导内质网应激、胰岛素炎症和人类白细胞抗原I类分子的大量过度表达 β-细胞，1型糖尿病的三个特征。总体而言，这些观察表明干扰素-α发挥了关键作用。 1型糖尿病早期β细胞和免疫系统之间的串扰信号。使用异种移植物 模型和活体动物成像研究，我们最近进行了新的观察，即干扰素-α刺激快速 活性氧(ROS)在人类β细胞亚群中的积累。众所周知，β- 细胞对ROS的积聚非常敏感，对ROS的不适应反应可能导致β-细胞 细胞凋亡。因此，我们假设人β细胞对干扰素-1的反应表现出快速的ROS积聚。 胰岛内的α具有独特的分子特征，使它们易于在T1D早期凋亡 发病机制。为了验证这一假设，我们将表征显示快速积累的细胞子集 体内ROS对干扰素-α暴露的反应，并确定这些细胞是否选择性地在早期 细胞凋亡。当前提案中概述的实验是专门设计来识别和表征 与β相关的一些关键早期事件-人类胰岛细胞凋亡，长期目标是 在高危人群中确定预防糖尿病的新治疗目标。

PROJECT SUMMARY/ABSTRACT The incidence of diabetes in the US population has been rapidly increasing over the past several decades. Type 1 diabetes is a result of β-cell death, or apoptosis of the insulin-producing cells in the pancreas. However, we are currently limited in our understanding of the molecular events that are involved in the initiation of pancreatic β-cell apoptosis and on the role for β-cell heterogeneity in the pathogenesis of type 1 diabetes. Interferon (IFN)-α-mediated signaling is a key component of type 1 diabetes pathophysiology. Children genetically at risk for type 1 diabetes have a type I IFN-inducible transcriptional signature in blood cells that precedes appearance of autoantibodies. Type I IFN is also expressed in pancreatic islets from people with type 1 diabetes and laser-captured islets from living donors with recent onset type 1 diabetes show an increase in IFN-stimulated genes. IFN-α induces ER stress, insulitis, and a massive HLA class I overexpression in human β-cells, three hallmarks of type 1 diabetes. Collectively, these observations suggest a critical role for IFN-α signaling in the crosstalk between β-cells and the immune system in early type 1 diabetes. Using a xenograft model and live animal imaging studies, we recently made the novel observation that IFN-α stimulates a rapid accumulation of reactive oxygen species (ROS) within a subset of human β-cells. It is well established that β- cells are exquisitely sensitive to ROS accumulation, and a maladaptive response to ROS can lead to β-cell apoptosis. Therefore, we hypothesize that human β-cells exhibiting rapid ROS accumulation in response to IFN- α within the islet have a unique molecular signature that predisposes them to early apoptosis in T1D pathogenesis. To test this hypothesis, we will characterize the subset of cells exhibiting rapid accumulation of ROS in response to IFN-α exposure in vivo and determine whether these cells are selectively targeted for early apoptosis. The experiments outlined in the current proposal are specifically designed to identify and characterize some of the key early events associated with β-cell apoptosis in human islets, with the long-term goal of identifying novel therapeutic targets to prevent diabetes in the at-risk population.