Epigenetic determinants of beta cell development and function

项目摘要/摘要 胰腺β细胞产生的胰岛素是葡萄糖代谢的关键刺激因素，因此它是至关重要的。 胰岛素的分泌是根据能量状态的变化进行调整的。胰岛素的分泌受到营养物质的强烈调节。 和荷尔蒙随着进食的反应而变化。如果美联储的状态持续存在，就像营养过剩一样，自适应控制 机制使胰岛素分泌反应变得越来越敏感，以满足增加的胰岛素需求。 然而，长期营养过剩也会导致适应不良，导致β细胞衰竭和2型糖尿病。 (T2D)。β细胞如何读取营养信号并将这些信号转化为适应和适应不良反应 人们对此知之甚少。在这笔赠款的支持下，我们已经证明了营养敏感的组蛋白去甲基酶 LSD1介导营养诱导的β细胞表观基因组的变化，以调节适应性胰岛素分泌。 具体地说，我们发现Lsd1改变了与β-细胞相连的基因调控元件的表观遗传状态 营养反应基因，从而调节胰岛素分泌反应的幅度。因此，LSD1 作为β细胞营养环境、表观基因组和转录之间的整合枢纽 输出。我们的初步研究进一步表明，LSD1抑制在瘦状态下是适应的，但 适应不良，并促进肥胖症中的β细胞功能衰竭。这项建议的目标是确定 LSD1感知营养并洞察代谢信号如何在LSD1上收敛的机制 和表观基因组，使适应性β细胞反应不适应。我们将采用最先进的技术 方法，包括新的小鼠模型，人类胰岛实验，单细胞分辨标测 染色质状态和基因表达，以及尖端计算分析。在目标1中，我们将确定 LSD1如何感知营养物质并调节β-细胞的染色质状态。研究营养素传感技术 机制，我们将操纵LSD1‘S代谢调节的辅因子FAD，并测量对LSD1- β细胞中受调控的过程。此外，我们还将对LSD1的S的酶和非酶功能进行剖析 调节β细胞表观基因组，使用新的小鼠模型和体外实验。在目标2中，我们将确定 LSD1抑制触发不良适应过程加速β细胞失代偿的机制 在T2D中。利用代谢应激的小鼠和胰岛遗传模型，我们将操纵LSD1的活性和 研究这些操作如何影响β细胞染色质状态、基因表达和表型。在目标3中，我们 将研究Lsd1在人类β细胞中的作用。在这里，我们将利用转录和染色质图谱 从非糖尿病、糖尿病前期和T2D供体胰岛的集合中产生，以确定LSD1- 受调节的程序导致了T2D中的β-cell故障。通过揭示β细胞的基本机制 解读营养信号，这项提议将被证明是确定预防或逆转战略的关键 适应不良的过程和β细胞故障。

PROJECT SUMMARY/ABSTRACT Insulin produced by pancreatic β-cells is the key stimulus for glucose metabolism, and therefore it is critical that insulin secretion is adjusted to changes in energy state. Insulin secretion is acutely regulated by nutrients and hormones that change in response to feeding. If the fed state persists, as in overnutrition, adaptive control mechanisms increasingly sensitize the insulin secretory response to meet the increased insulin demand. However, long-term overnutrition can also become maladaptive and lead to β-cell failure and type 2 diabetes (T2D). How β-cells read nutrient signals and translate these signals into adaptive and maladaptive responses is poorly understood. Supported by this grant, we have shown that the nutrient-sensitive histone demethylase LSD1 mediates nutrient-induced changes to the β-cell epigenome to regulate adaptative insulin secretion. Specifically, we found that LSD1 modifies the epigenetic state of gene regulatory elements linked to β-cell nutrient response genes, thereby modulating the amplitude of the insulin secretory response. Thus, LSD1 functions as an integration hub between the β-cell’s nutrient environment, the epigenome and transcriptional output. Our preliminary studies further show that LSD1 inhibition is adaptive in a lean state, but becomes maladaptive and promotes β-cell failure in obesity. The objective of this proposal is to determine the mechanisms by which LSD1 senses nutrients and to gain insight into how metabolic cues converge on LSD1 and the epigenome to render the adaptive β-cell response maladaptive. We will employ state-of-the-art approaches, encompassing novel mouse models, human islet experiments, single cell resolved mapping of chromatin state and gene expression, and cutting-edge computational analyses. In Aim 1, we will determine how LSD1 senses nutrients and regulates chromatin state in β-cells. To investigate the nutrient sensing mechanism, we will manipulate LSD1’s metabolically regulated co-factor FAD and measure effects on LSD1- regulated processes in β-cells. Furthermore, we will dissect LSD1’s enzymatic and non-enzymatic functions in regulating the β-cell epigenome, using novel mouse models and in vitro experiments. In Aim 2, we will identify mechanisms by which LSD1 inhibition triggers maladaptive processes that accelerate β-cell decompensation in T2D. Employing genetic mouse and islet models of metabolic stress, we will manipulate LSD1 activity and study how these manipulations affect β-cell chromatin state, gene expression, and phenotypes. In Aim 3, we will examine the role of LSD1 in human β-cells. Here, we will leverage transcriptomic and chromatin maps we generated from a collection of nondiabetic, prediabetic, and T2D donor islets to determine whether the LSD1- regulated program contributes to β-cell failure in T2D. By unveiling fundamental mechanisms by which β-cells interpret nutrient signals, this proposal will prove critical for identifying strategies to prevent or reverse maladaptive processes and β-cell failure.