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

项目总结/摘要 糖尿病已成为一个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 这在很大程度上是由于功能性β细胞的丧失。目前主要的研究工作集中在 了解糖尿病中的β细胞衰竭，并开发有效的治疗方法， 糖尿病中的β细胞缺陷。尽管在这些方面取得了重大进展， 有效的β细胞疗法，主要是由于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。我们最近的工作已经确定DNA甲基化是 调节β细胞身份和功能的表观遗传机制。此外，我们发现DNA甲基化 在糖尿病β细胞中，定义功能β细胞表型的模式被破坏，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（5 mC）通过其转化为羟基化形式（5-羟甲基胞嘧啶; 5 hmC）是必不可少的 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 5 mC和5 hmC的模式对于β细胞稳态是至关重要的，并且在糖尿病中被破坏，导致β- 电池故障。因此，我们试图确定酶如何调节5 mC和5 hmC之间的平衡， 控制功能性β细胞群并影响糖尿病易感性。我们将利用小鼠遗传学、疾病 模型，人类胰岛研究，以及最先进的全基因组表观遗传分析方法，以解决 以下目标：在具体目标1中，我们的目标是建立5 mC和5 hmC模式的要求， 从祖细胞分化β细胞。具体目标2旨在确定动态的贡献 β细胞复制和适应能力中5 mC和5 hmC模式的重塑。在具体目标3中，我们 解决环境因素如氧化应激和代谢物变异是否以及如何破坏β细胞 5 mC和5 hmC环境导致β细胞衰竭和糖尿病。 拟议的研究将描绘一种新的调控模块，控制β细胞发育， 生长，并建立一个基本的监管模式，连接β细胞环境，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，提供新的线索，以促进β- 细胞分化、功能和扩增，以实现β细胞再生和替代的策略 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.