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。这一提议基于一个工作假设，即特定的细胞类型和组织通过表观基因组的全球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，以解决目前排除复杂组织中细胞类型特异性表观遗传分析的方法学缺陷。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，标记的组蛋白将被掺入感兴趣细胞的染色质中，从而可以从任何动物模型或复杂组织中的特定细胞中分离染色质。我们打算使用线虫秀丽隐杆线虫来开发CI-ChIP。蠕虫的遗传易处理性和衰老生物学提供了许多优势。CI-ChIP的开发将为C.优雅此外，在衰老过程中以及在延长寿命的条件下，基因表达的变化首次可以在组织水平上进行测量。这将使调查的分子基础的差异率老化和贡献的每一个主要细胞类型的蠕虫。为了探索表观遗传变化在哺乳动物衰老中的作用，CI-ChIP将应用于表达标记组蛋白的转基因小鼠，这些标记组蛋白靶向具有明显年龄相关病理学的组织，包括脑、心脏、骨骼肌、血管系统和胰腺。这将允许在任何疾病、发育或生理学的小鼠模型中以细胞类型特异性分辨率进行全局表观遗传分析。最后，可以想象的是，CI-ChIP可能会导致预测与年龄相关的退行性疾病风险的技术。

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