Aging and the unstable epigenome

描述（由申请人提供）：已经提出了各种假设来解释细胞和组织水平上的衰老过程。其中最常见的是核和线粒体DNA损伤和突变的积累，氧化应激和其他内在化学反应引起的大分子损伤，端粒侵蚀和功能障碍，癌基因的激活，增殖组织中干细胞更新的恶化。最有可能的是，所有这些现象的重叠将导致细胞和生物体老化。然而，在这里，我们提出了一个新的范式：表观基因组的改变在很大程度上促进了衰老过程。在这个应用中，我们提出表观遗传变化是衰老的一个标志。我们将分析几种表观遗传标记，包括DNA CpG甲基化和染色质修饰，在体外和体内经历衰老的细胞。此外，我们将分析这些标记在Cockayne综合征细胞，一种早衰综合征。这个表观基因组定位项目将利用甲基化CpG岛恢复测定（MIRA）技术进行DNA甲基化分析和染色质免疫沉淀分析组蛋白修饰。全基因组分析将通过微阵列和高通量DNA序列分析来完成。该资助建议在衰老和早衰综合征的时间过程中，在组蛋白修饰、DNA甲基化和基因表达水平上对表观基因组进行深入分析。从相同的身体部位连续获得的同质细胞类型将使我们能够进行有意义的比较。这些数据将允许对衰老过程中发生的表观遗传变化的程度和特异性进行估计，因此我们将能够更好地评估表观遗传学对衰老的确切贡献。

DESCRIPTION (provided by applicant): Various hypotheses have been put forward to explain the aging process at both the cellular and organismal level. Among the most popular ones are accumulation of nuclear and mitochondrial DNA damage and mutations, damage to macromolecules induced by oxidative stress and other intrinsic chemical reactions, telomere erosion and dysfunction, activation of oncogenes, and a deterioration of stem cell renewal in proliferating tissues. Most likely, an overlap of all of these phenomena will contribute to cellular and organismal aging. However, here we propose a new paradigm: that alterations of the epigenome contribute substantially to the aging process. In this application, we propose that epigenetic changes are a hallmark of aging. We will analyze several epigenetic marks including DNA CpG methylation and chromatin modifications in cells that undergo aging in vitro and in vivo. In addition, we will analyze these marks in Cockayne syndrome cells, a premature aging syndrome. This epigenome mapping project will make use of the methylated CpG island recovery assay (MIRA) technique for DNA methylation analysis and chromatin immunoprecipitation for analysis of histone modifications. Genome-wide analysis will be accomplished by microarray and high throughput DNA sequence analysis. This grant proposes an in-depth analysis of the epigenome, at the level of histone modifications, DNA methylation and gene expression during the time course of aging and in premature aging syndromes. A homogenous cell type derived from identical body sites and obtained serially from the same individuals will enable us to make meaningful comparisons. The data will allow an estimation of the extent and specificity of epigenetic changes that occur during the aging process, and hence we will be in a position to better assess the exact contribution of epigenetics to aging.