Modeling the Aging Epigenome

描述 摘要： 全球表观遗传变化在衰老过程和年龄相关退行性疾病中的作用尚不清楚。这一建议是基于一个工作假设，即特定的细胞类型和组织通过表观基因组的全局变化来驱动衰老过程。为了探索这一假设，我们设想了一种新的系统来解决目前在复杂组织中排除细胞类型特异性表观遗传学分析的方法学缺陷。计划中的新方法，我们称之为染色质分离和染色质免疫沉淀(CI-CHIP)，将涉及使用细胞类型特异性启动子在感兴趣的细胞中转基因表达标记的核心组蛋白。然后，标记的组蛋白将被结合到目标细胞的染色质中，从而允许从任何动物模型或复杂组织的特定细胞中分离出染色质。我们打算利用线虫秀丽线虫来开发CI-芯片。蠕虫的遗传易驯化和衰老生物学提供了许多优势。CI芯片的发展将对线虫的基因表达和衰老的表观遗传学的研究产生直接的好处。此外，在衰老和延长寿命的条件下，基因表达的变化可以第一次在组织水平上进行测量。这将使研究不同衰老速率的分子基础以及蠕虫中每种主要细胞类型的贡献成为可能。为了探索表观遗传学变化在哺乳动物衰老中的作用，CI-CHIP将被应用于表达标记组蛋白的转基因小鼠，这些组织蛋白的目标是具有明显年龄相关病理的组织，包括大脑、心脏、骨骼肌、血管和胰腺。这将允许在任何疾病、发育或生理的小鼠模型中以特定细胞类型的分辨率进行全球表观遗传学分析。最后，可以想象，CI-CHIP可能会导致预测有患年龄相关退行性疾病风险的个人的技术

DESCRIPTION Abstract: The role of global epigenetic changes in the aging process and age-related degenerative disorders is unknown. This proposal is based on the working hypothesis that specific cell types and tissues drive the aging process through global changes in the epigenome. To explore this hypothesis, we have conceived a novel system to address the methodological shortcomings that currently preclude cell-type-specific epigenetic analysis in complex tissues. The planned new approach, which we term Chromatin Isolation and Chromatin Immunoprecipitation (CI- ChIP), will involve transgenic expression of a tagged core histone in cells of interest using a cell type-specific promoter. The tagged histone would then be incorporated into the chromatin of the cells of interest, permitting the isolation of chromatin from specific cells in any animal model or complex tissue. We intend to use the nematode worm, Caenorhabditis elegans, to develop CI- ChIP. The genetic tractability and aging biology of the worm offers many advantages. Development of CI-ChIP would have immediate benefits for the study of gene expression and the epigenetics of aging in C. elegans. Furthermore, changes in gene expression during aging and under conditions that extend longevity could be measured at the tissue level for the first time. This will enable investigation of the molecular basis of differential rates of aging and the contribution of each of the major cell types in the worm. To explore the role of epigenetic changes in mammalian aging, CI-ChIP will be applied to transgenic mice expressing tagged histones targeted to tissues with pronounced age-related pathology, including the brain, heart, skeletal muscle, vasculature and pancreas. This would allow for global epigenetic analysis at cell type-specific resolution in any mouse model of disease, development or physiology. Finally, it is conceivable that CI-ChIP might lead to technology for predicting individuals at risk for age- related degenerative disorde