The Integrated Stress Response in Human Islets During Early T1D

摘要 1型糖尿病(T1D)的发病机制包括一系列侵袭性自身免疫 向胰岛β细胞转化为炎症引起的β细胞功能缺陷。一种一直以来 近年来，越来越多的研究认为，细胞内信号通路源于β细胞对 炎症可以导致异常蛋白的产生，这些蛋白作为新的抗原启动或 加剧自身免疫力。这一观点促使我们的团队识别并干预细胞内 当T1D从症状前进展到症状时影响β细胞弹性的信号通路 各阶段。本提案采用响应RFA-DK-19-024的多学科团队科学方法 确定并干预影响人类胰岛的早期T1D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传递到 激活一系列eif2α激酶。EIF2mrna的磷酸化抑制α的翻译启动 努力调整能源支出，以缓解普遍存在的压力。翻译抑制的mRNA和 它们的相关蛋白被隔离在细胞内应激颗粒(SGS)中，SGS的形成是 被认为是将细胞信号转向紧急反应。我们的初步数据显示，ISR 在T1D早期在胰岛中被激活，连接膜衍生脂到生产的途径 促炎性脂质中间产物的合成可能触发ISR和SGS的形成。我们假设 ISR的激活和SGs的形成是启动T1Dβ细胞应激的早期细胞反应 决定细胞存活，并可监测T1D前期和早期患者，侵袭性最小。 我们的协作团队将通过以下目标来验证这一假设： 目的1：确定应激颗粒的形成机制及其在激活后的命运 人胰岛的综合应激反应。 目的2：确定与脂代谢、ISR激活和应激相关的分子事件 人胰岛中颗粒的形成。 目的3：确定EVS中的蛋白质、RNA和脂肪是人类胰岛的假定生物标记物 综合应激反应和T1D风险。 这项应用利用了6个多PI在β-细胞生物学、脂类和二十烷类生物学方面的专业知识， 功能基因组学、蛋白质组学、计算模型和临床胰岛研究。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.