The Integrated Stress Response in Human Islets During Early T1D

摘要 1型糖尿病（T1 D）的发病机制包括从侵袭性自身免疫 胰岛β细胞的功能缺陷，由炎症引起。一种观点， 近年来，越来越多的人认为，β细胞对 炎症可导致异常蛋白质的产生，所述异常蛋白质充当新抗原， 加剧自身免疫这一观点促使我们的团队识别和干预细胞内 T1 D从症状前进展为症状时影响β细胞恢复力的信号通路 阶段本提案采用多学科团队科学方法，响应RFA-DK-19-024 定义和干预影响人类胰岛的早期T1 D疾病过程。综合应激反应 (ISR)是一种细胞保护过程，环境应激信号在细胞内被转导， 激活多种eIF 2 α激酶。eIF 2 α的磷酸化作用阻止了一般mRNA的翻译起始， 努力调整能量消耗，以减轻当前的压力。被抑制的mRNA和 它们的相关蛋白被隔离到细胞内应激颗粒（SG）中， 被认为是将细胞信号转移到紧急反应中。我们的初步数据显示， 在早期T1 D期间在胰岛中被激活，并且将膜衍生脂质与产生 促炎脂质中间体的释放可能触发ISR和SG的形成。我们假设 ISR的激活和SG的形成是T1 D中启动β细胞应激的早期细胞应答， 确定细胞存活，并可以在T1 D前和早期个体中以最小的侵袭性进行监测。 我们的合作团队将通过以下目标来测试这一假设： 目的1：确定应激颗粒形成的机制及其在激活后的命运。 人类胰岛的综合应激反应。 目的2：确定与脂质代谢、ISR激活和应激相关的分子事件 人类胰岛中的颗粒形成。 目的3：鉴定EV中的蛋白质、RNA和脂质货物作为人类胰岛的推定生物标志物 综合应激反应和T1 D风险。 该应用程序利用了6个Multi-PI在β细胞生物学、脂质和类花生酸生物学方面的专业知识， 功能基因组学、蛋白质组学、计算建模和临床胰岛研究。这个项目的影响 将提供关于人类胰岛中未研究的应激途径的新知识，并识别和验证 反映这种压力状态的生物标志物面板。

ABSTRACT The pathogenesis of type 1 diabetes (T1D) encompasses a spectrum ranging from aggressive autoimmunity toward islet β cells to defects in β-cell function that arise from inflammation. A perspective that has been gaining traction in recent years posits that intracellular signaling pathways arising from the β cell response to inflammation can lead to the production of aberrant proteins that serve as neoantigens that initiate or exacerbate autoimmunity. This perspective has prompted our Team to identify and intervene in intracellular signaling pathways that affect β-cell resilience as T1D progresses from the presymptomatic to symptomatic stages. This proposal takes a multidisciplinary Team Science approach that is responsive to RFA-DK-19-024 to define and intervene in early T1D disease processes affecting human islets. The integrated stress response (ISR) is a cytoprotective process whereby environmental stress signals are transduced intracellularly to activate a host of eIF2α kinases. The phosphorylation of eIF2α halts general mRNA translation initiation in an effort to redirect energy expenditure to mitigate the prevailing stress. The translationally inhibited mRNAs and their associated proteins are sequestered into intracellular stress granules (SGs), the formations of which are thought to divert cellular signaling toward an emergency response. Our preliminary data suggest that the ISR is activated in islets during early T1D, and that the pathway linking membrane-derived lipids to the production of proinflammatory lipid intermediates may trigger the ISR and the formation of SGs. We hypothesize that the activation of the ISR and formation of SGs is an early cellular response initiating β cell stress in T1D that determines cell survival and can be monitored in pre- and early T1D individuals with minimal invasiveness. Our collaborative Team will test this hypothesis through the following aims: Aim 1: Define the mechanisms of stress granule formation and their fate upon activation of the integrated stress response in human islets. Aim 2: Determine the molecular events linking lipid metabolism, activation of the ISR, and stress granule formation in human islets. Aim 3: Identify protein, RNA, and lipid cargo in EVs as putative biomarkers of the human islet integrated stress response and T1D risk. This application leverages the expertise of 6 Multi-PIs in β-cell biology, lipid and eicosanoid biology, functional genomics, proteomics, computational modeling, and clinical islet studies. The impact of this project will be to deliver new knowledge on an unstudied stress pathway in human islets and to identify and validate biomarker panels that reflect this stress state.