Epigenomic Profiling of Normal and Diabetic Pancreatic Beta-Cells

描述(申请人提供)：糖尿病是一种终生慢性疾病，2007年全球估计有1.8亿患者。在过去的十年里，尽管肥胖和外周胰岛素抵抗是导致糖尿病前期的因素，但很明显，胰腺细胞衰竭是导致向显性糖尿病过渡的最终事件。细胞衰竭在这里被定义为两种功能的丧失，即葡萄糖刺激的胰岛素分泌，以及细胞质量不足，要么是由于细胞凋亡增加，要么是因为无法对代谢需求做出反应而增殖。虽然有几种药物被用来减少胰岛素抵抗和增加胰岛素分泌，但没有一种药物能解决这一问题 --单元故障。事实上，目前还没有人知道可以允许这种药物开发的好靶点。由于？细胞在糖尿病的发病机制中起着如此核心的作用，而且由于表观遗传因素(即反映在染色质状态中的转录程序的长期变化)可能是导致糖尿病的生活方式变化和环境因素的主要结果，我们将确定健康和2型糖尿病人？细胞的表观基因组。这一努力将为确定未来可针对细胞衰竭的新疗法开发的途径和基因奠定基础。具体地说，我们将使用芯片序列技术来确定从50名健康和50名2型糖尿病器官捐赠者分离的细胞中的染色质标记的激活和抑制。其次，我们将分析相同细胞制剂中的microRNA图谱，因为miRNAs是修改糖尿病细胞转录组的有力候选者。第三，我们将分析宾夕法尼亚大学发现的一种新的染色质标记，它将应激介质AMPK与染色质状态联系起来。第四，我们将进行全面的计算生物学分析，以确定糖尿病细胞中受影响的节点和调控途径。 与公共卫生相关：糖尿病是一种终生慢性病，2007年全球患病率估计为1.8亿。在过去的十年里，已经很明显的是，产生胰岛素的胰岛β细胞的衰竭是导致向显性糖尿病过渡的最后事件，尽管肥胖和外周胰岛素抵抗是导致糖尿病前期的因素。我们将确定导致糖尿病β细胞失效的“表观遗传学”，也就是不基于突变的基因组变化。这项工作将确定治疗2型糖尿病的新的潜在药物靶点。

DESCRIPTION (provided by applicant): Diabetes mellitus is a lifelong chronic disease with worldwide prevalence estimated at 180 million patients in 2007. Over the past decade, it has become clear that failure of the pancreatic ¿-cell is the final event causing the transition to overt diabetes, even though obesity and peripheral insulin resistance are the factors leading to pre-diabetes. ¿-cell failure here is defined as loss of both function, i.e. glucose stimulated insulin secretion, and inadequate ¿-cell mass, either by increased apoptosis or a failure to proliferate in response to metabolic demand. While several drugs are in use to reduce insulin resistance and increase insulin secretion, none exist that address ¿-cell failure. In fact, at present, no good targets are known that would allow such drug development. Because the ¿-cell plays such a central role in the pathogenesis of diabetes, and because epigenetic factors (i.e. long term changes in the transcriptional program reflected in chromatin status) are likely to be the predominant consequence of the life-style changes and environmental factors that lead up to diabetes, we will determine the epigenome of both healthy and type 2 diabetic human ¿-cells. This effort will lay the groundwork to defining the pathways and genes that can be targeted in the future for the development of new therapies that address ¿-cell failure. Specifically, we will determine both activating and repressing chromatin marks in ¿-cells isolated from 50 healthy and 50 type 2 diabetic organ donors using ChIP-Seq technology. Secondly, we will analyze the microRNA profile in the same ¿-cell preparations, as miRNAs are strong candidates to modify the transcriptome of the diabetic ¿-cell. Third, we will analyze a novel chromatin mark discovered at Penn that links the stress mediator AMPK to chromatin status. Fourth, we will perform a comprehensive computational biology analysis to identify the nodes and regulatory pathways that are affected in diabetic ¿-cells. PUBLIC HEALTH RELEVANCE: Diabetes mellitus is a lifelong chronic disease with worldwide prevalence estimated at 180 million patients in 2007. Over the past decade, it has become clear that failure of the pancreatic beta-cell, the insulin producing cell, is the final event causing the transition to overt diabetes, even though obesity and peripheral insulin resistance are the factors leading to pre- diabetes. We will determine the "epigenetic", that is not mutation based, changes in the genome of the diabetic beta-cell that cause it to fail. This work will identify new potential drug targets for the treatment of type 2 diabetes.