Functional and molecular characterization of the human islet interferon alpha response

项目总结/摘要 在过去的几年里，美国人口中糖尿病的发病率迅速增加。 几十年1型糖尿病是胰腺中β细胞死亡或胰岛素产生细胞凋亡的结果。 然而，我们目前对参与启动的分子事件的理解有限， 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（IFN）-α介导的信号传导是1型糖尿病病理生理学的关键组成部分。儿童 在遗传上具有1型糖尿病风险的人在血细胞中具有I型IFN-诱导的转录特征， 在自身抗体出现之前。I型干扰素也表达在来自I型糖尿病患者的胰岛中， 1型糖尿病和激光捕获的胰岛从生活捐赠者与最近发病的1型糖尿病显示增加， IFN刺激基因。IFN-α诱导人内质网应激、胰岛炎和大量HLA I类基因过表达 1型糖尿病的三大特征总的来说，这些观察结果表明IFN-α的关键作用 早期1型糖尿病中β细胞和免疫系统之间串扰的信号传导。使用异种移植 模型和活体动物成像研究中，我们最近进行了新的观察，IFN-α刺激快速的 在一些实施方案中，本发明涉及人β细胞亚群内活性氧（ROS）的积累。已确定β- 细胞对ROS积累非常敏感，对ROS的适应不良反应可导致β细胞 凋亡因此，我们假设人β细胞对IFN-γ的反应中表现出快速的ROS积累， 胰岛内的α具有独特的分子特征，使其易于在T1 D中发生早期凋亡 发病机制为了检验这一假设，我们将表征表现出快速积累的细胞亚群。 ROS在体内对IFN-α暴露的反应，并确定这些细胞是否被选择性地靶向用于早期 凋亡本提案中概述的实验是专门设计用于识别和表征 一些与人类胰岛β细胞凋亡相关的关键早期事件，长期目标是 确定新的治疗靶点，以预防高危人群的糖尿病。

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.