Regulation of beta-cell homeostasis by DNA methylation and hydroxymethylation.

项目摘要/摘要 糖尿病已经成为一项重大的公共卫生危机，困扰着美国近3000万人， 这些数字继续以惊人的速度上升。1型和2型糖尿病都是由胰岛素引起的 功能不全，很大程度上是由于功能上的β细胞的丧失。重要的研究工作目前集中在 了解糖尿病中的β细胞衰竭，并开发有效的治疗方法来补充 糖尿病患者的β细胞缺乏症。尽管在这些方面取得了重大进展，但发展方面仍然存在挑战。 有效的β细胞疗法，主要是因为我们目前对调控机制的理解存在差距 正常的β细胞发育、功能和生长。我们最近的研究发现DNA甲基化是 调控β细胞特性和功能的表观遗传机制。此外，我们发现DNA甲基化 定义功能性β细胞表型的模式在糖尿病的β细胞中被破坏，这表明动态 DNA甲基化的本质。我们的初步研究表明，DNA甲基化的动态重塑(5- 甲基胞嘧啶；5mC)通过其转化为羟化形式(5-羟甲基胞嘧啶；5hmC)是 β细胞分化、功能和适应性反应。我们假设特定阶段的、适当的 5mC和5hmC的模式对β细胞稳态至关重要，在糖尿病中被破坏，导致β-细胞死亡。 电池故障。因此，我们试图确定酶如何调节5mC和5hmC之间的平衡 控制功能性的β细胞团，影响糖尿病的易感性。我们将利用老鼠的遗传学、疾病 模型、人类胰岛研究和最先进的全基因组表观遗传图谱方法来解决 以下目标：在具体目标1中，我们旨在建立5mC和5hmC图形的要求 β细胞与祖细胞的分化。具体目标2试图定义动态的贡献 β细胞复制和适应能力中5mC和5hmC模式的重塑。在具体目标3中，我们 探讨氧化应激和代谢物变化等环境因素是否以及如何扰乱β细胞 5mC 5hmC环境会导致β细胞衰竭，以及糖尿病。 拟议的研究将描绘一个新的调控模块，管理β细胞的发育和 生长，并建立一个基本的调控范式，将β细胞环境、新陈代谢和 表观基因组。我们的工作可能会产生广泛而重大的影响，通过提供新的线索来促进贝塔- 细胞分化、功能和扩增，朝着旨在恢复和替换β细胞的策略 用于糖尿病治疗。

PROJECT SUMMARY/ABSTRACT Diabetes has become a major public health crisis, afflicting nearly 30 million people in the United States, and these numbers continue to rise at an alarming rate. Both type 1 and type 2 diabetes result from insulin insufficiency, in large part due to loss of functional beta-cells. Significant research efforts are currently focused on understanding beta-cell failure in diabetes, and developing effective therapeutic approaches to replenishing the beta-cell deficit in diabetes. Despite significant advances in these aspects, challenges remain in development of effective beta-cell therapies, primarily due to gaps in our current understanding of mechanisms that regulate normal beta-cell development, function, and growth. Our recent work has identified DNA methylation as a pivotal epigenetic mechanism that regulates beta-cell identity and function. Moreover, we found that DNA methylation patterns defining functional beta-cell phenotype are disrupted in the diabetic beta-cells, suggesting dynamic nature of DNA methylation. Our preliminary studies indicate that dynamic remodeling of DNA methylation (5- methylcytosine; 5mC) via its conversion to a hydroxylated form (5-hydroxymethylcytosine; 5hmC) is essential for beta-cell differentiation, function, and adaptive response. We hypothesize that stage-specific, appropriate patterning of 5mC and 5hmC is critical for beta-cell homeostasis, and is disrupted in diabetes leading to beta- cell failure. Thus, we seek to determine how enzymatic regulation of the balance between 5mC and 5hmC governs functional beta-cell mass and affects diabetes susceptibility. We will employ mouse genetics, disease models, human islet studies, and state-of-the-art genome wide epigenetic profiling methods to address the following aims: In Specific Aim 1, we aim to establish the requirement of 5mC and 5hmC patterning in differentiation of beta-cells from progenitors. Specific Aim 2 seeks to define the contribution of dynamic remodeling of 5mC and 5hmC patterns in beta-cell replication and adaptive capacity. In Specific Aim 3, we address if and how environmental factors like oxidative stress and metabolite variation can disrupt the beta-cell 5mC 5hmC landscape to drive beta-cell failure, and diabetes. The proposed studies will delineate a novel regulatory module that governs beta-cell development and growth, and establish a fundamental regulatory paradigm that link beta-cell environment, metabolism and epigenome. Our work is likely to have a broad and significant impact by providing novel clues to promote beta- cell differentiation, function, and expansion towards strategies aimed at beta-cell rejuvenation and replacement for diabetes therapy.