Regulating stress response to promote postnatal beta-cell function and survival

调节应激反应以促进产后 β 细胞功能和存活

基本信息

批准号：
10580784
负责人：
Guoqiang Gu
金额：
$ 48.71万
依托单位：
VANDERBILT UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-04-01 至 2025-03-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10580784
关键词：
5&apos Flanking Region ATF6 gene Adult Affect Anabolism Apoptotic Attenuated Beta Cell Cell Death Cell Line Cell Proliferation Cell Survival Cell Transplantation Cell physiology Cells Cessation of life ChIP-seq Compensation Complex Development Diabetes Mellitus Disease Down-Regulation Failure Family Functional disorder Gene Activation Gene Expression Genes Genetic Transcription Glucose Glucose Intolerance Goals Heat-Shock Response Histone Deacetylase Histone Deacetylation Histones Homeostasis Human Hyperglycemia Hypoglycemia Immunodeficient Mouse In Vitro Insulin Insulin Resistance Interruption Islet Cell Islets of Langerhans Knowledge Lead Link Mediating Messenger RNA Metabolic Metabolic stress Mitochondria Modeling Molecular Molecular Target Mus Myelin Non-Insulin-Dependent Diabetes Mellitus Obesity Open Reading Frames Output Oxidative Stress Peripheral Persons Physiology Process Production Proinsulin Proteins Proteomics Publishing Reactive Oxygen Species Regulation Repression Role Stress Structure of beta Cell of islet Testing Tissues Translations Up-Regulation Workload biological adaptation to stress blood glucose regulation derepression gain of function gene product gene repression glucose metabolism improved in vivo in vivo evaluation insulin secretion islet islet stem cells knock-down loss of function novel paralogous gene postnatal prevent recruit response stressor transcription factor transcriptome sequencing

项目摘要

Workload-induced pancreatic islet β-cell dysfunction, loss-of identity, and cell death, commonly known as β-cell failure, is the hallmark of type 2 diabetes (T2D). This disease usually starts with obesity-induced insulin resistance, when peripheral tissues need higher levels of circulating insulin for glucose storage and usage. Islet β-cells compensate by expanding β-cell mass and increasing insulin output per cell, which requires upregulated insulin biosynthesis and oxidative glucose metabolism. These produce unfolded proinsulin in the ER and reactive oxygen species (ROS) in mitochondria, which at high levels can decimate β cells. Thus, β cells constantly activate stress response by stimulating the activity of several early-stage SRGs, including Atf6, IRE1, PERK, Hsf1, and Nurf2, to lead to: 1) attenuated overall protein translation; 2) enhanced translation of some SRG mRNAs that have special features such as upstream open reading frame (uORF) 5’ to the main ORF; 3) upregulated expression of some late-stage SRGs. The overall effect of these responses is to remove unfolded proteins/ROS for proteomic homeostasis and sustainable β-cell function. However, over-activating some late-stage SRGs such as Atf4 and Hsps induces β-cell failure by turning on some proapoptotic genes or by exceedingly lowering overall protein translation. Thus, it is imperative for β-cells to limit the levels of failure- causing SRGs for sustainable high-level of insulin output. An emerging model from our recent published findings is that a transcriptional complex containing Myt TFs and Sin3 can selectively repressing these failure- causing SRGs. Myt TFs are a family of three myelin transcription factors (Myt1, 2, and 3) highly expressed in islet cells. Sin3, including Sin3a and Sin3b, is a coregulator that represses transcription by recruiting histone deacetylases (HDACs) to modify histones. We showed that Myt TFs and Sin3 can form a transcription complex in β cells. Inactivating these genes in mouse and human β cells causes cell dysfunction and/or death while overactivating late-stage β-cell-failure-causing SRGs but not early stage SRGs. Intriguingly, Myt TFs, particularly Myt3, is induced by obesity-related stressors in mouse and human β cells, likely mediated by an uORF in 5’ flanking region of Myt3 mRNA. Importantly, MYT3 down-regulation accompanies human β-cell failure in T2D development. Our overarching hypothesis is that the stress-responsive Myt TFs, particularly Myt3, promote -cell function/survival by repressing late-stage SRGs via Sin3-mediated histone de-acetylation under both normal physiology and metabolic stress. Aim 1 will establish how MYT TFs repress SRG expression in a human β cell line and how manipulating MYT-TF levels will affect primary human β-cell function and survival. Aim 2 will define how metabolic stressors up-regulate Myt3 production and how this upregulation enable β-cell compensation under metabolic stress. We expect to uncover a tunable mechanism that can be explored for preventing/delaying β-cell failure and T2D.

工作负载引起的胰岛β细胞功能障碍，身份丧失和细胞死亡，通常称为 β细胞衰竭是2型糖尿病（T2D）的标志。这种疾病通常从肥胖引起的胰岛素开始耐药性时，当周围组织需要更高水平的循环胰岛素才能进行葡萄糖储存和使用。胰岛β细胞通过扩大β细胞质量和每个细胞的胰岛素输出增加来补偿，这需要上调胰岛素生物合成和氧化葡萄糖代谢。这些在线粒体中的ER和活性氧（ROS），在高水平上可以衰减β细胞。细胞通过刺激包括ATF6的几个早期SRG的活性来不断激活应力反应 IRE1，PERK，HSF1和NURF2导致：1）减弱总体蛋白质翻译； 2）增强的翻译一些具有特殊功能的SRG mRNA，例如上游开放阅读框（UORF）5英寸 orf; 3）更新一些晚期SRG的表达。这些响应的总体效果是删除展开的蛋白质/ROS用于蛋白质组学稳态和可持续β细胞功能。但是，过度激活某些后期SRG（例如ATF4和HSP）通过打开一些促凋亡基因或通过极大地降低整体蛋白质翻译。这是β细胞必须限制失败水平 - 导致SRGS用于可持续高水平的胰岛素输出。我们最近出版的新兴模型研究结果是，包含myt tfs和sin3的转录复合物可以选择性地反映这些失败 - 引起SRG。 Myt TF是一个高度表达的三个髓鞘转录因子（myt1、2和3）的家族胰岛细胞。 SIN3（包括SIN3A和SIN3B）是一个核心节，可通过募集组蛋白来反映转录脱乙酰基酶（HDACS）可修饰组蛋白。我们证明了MyT TFS和SIN3可以形成转录复合物在β细胞中。在小鼠和人β细胞中灭活这些基因会导致细胞功能障碍和/或死亡，而过度活化的晚期β细胞 - 失败引起的SRG，而不是早期SRG。有趣的是，myt tfs，特别是myt3是由小鼠和人β细胞中肥胖相关的应激源诱导的，可能是由 Uorf在Myt3 mRNA的5'侧面区域。重要的是，myt3下调涉及人β细胞 T2D开发失败。我们的总体假设是压力响应的myt tfs，尤其是 myt3，通过通过SIN3介导的组蛋白去乙酰化反射晚期SRG来促进细胞功能/生存在正常的生理和代谢压力下。 AIM 1将确定MyT TFS如何压制SRG 在人β细胞系中的表达以及操纵MYT-TF水平如何影响原代人β细胞功能和生存。 AIM 2将定义代谢压力源如何上调MYT3的产生以及如何上调上调在代谢应激下实现β细胞补偿。我们希望发现一种可调机制可以探讨用于防止/延迟β细胞衰竭和T2D。