L 1 element as an inrinsic factor of mammalian aging

L 1 元素作为哺乳动物衰老的内在因素

• 批准号: 8032436
• 负责人: Victoria Perepelitsa Belancio
• 金额: $ 11.44万
• 依托单位: TULANE UNIVERSITY OF LOUISIANA
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-03-15 至 2013-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8032436
• 关键词: Address; Age; Age of Onset; Aging; Biological Assay; Cell Aging; Cell Line; Cell model; Cells; Chronic; DNA Damage; Data; Deoxyribonuclease I; Disease; Double Strand Break Repair; Elements; Endothelial Cells; Fibroblasts; Genetic; Genome; Genomic Instability; Goals; Health; Healthcare; Human; Individual; Insertional Mutagenesis; L1 Elements; Lead; Longevity; Malignant Neoplasms; Mesenchymal Stem Cells; Messenger RNA; Molecular; Monkeys; Mutagenesis; Mutation; Normal Cell; Older Population; Pathway interactions; Population; Process; Property; Reporter; Reporting; Somatic Cell; Specificity; Staining method; Stains; Stem cells; Surveys; Testing; Tissues; Umbilical vein; Variant; Western Blotting; Whole Organism; adult stem cell; age group; aged; comparative; design; endonuclease; human adult stem cell; human stem cells; human tissue; mutant; prevent; research study; response; tissue culture

DESCRIPTION (provided by applicant): The goal of this proposal is to understand the mechanistic aspects of cellular responses to L1 activity, to evaluate L1 -induced mutagenesis and its contribution to DNA damage and associated aging, to determine whether this contribution increases with age, and to find out potential variation of this contribution among individuals. These goals are important because the existing data indicate that the DNA damage in the form of double-strand breaks (DSBs) inflicted by the L1-encoded DNA endonuclease is potentially much greater than the insult to the genome caused by the element via insertional mutagenesis. We detected endogenous L1 expression in a number of somatic cells. Therefore this type of DNA damage has consequences for the whole organism, not only for its progeny. We also wish to address the L1 contribution to the DNA damage and associated aging in human stem cells. For these studies we will manipulate L1 expression levels and correlate L1 activity with the resulting DNA damage by western blot analysis, g-H2AX foci staining, and COMET assays in normal cell lines. We will use reporter assay to quantify the mutagenic potential of L1 elements. We will use cultured primary cell models to determine L1 potential to accelerate cellular senescence in somatic and stem cells. Reported ability of L1 elements to inflict DNA damage and its endogenous expression in a number of human tissues fundamentally changes our understanding of the significance of the L1 expression and its impact on the health of the host. This project is designed to determine whether ongoing low levels of L1 expression in somatic and stem cells lead to a steady accumulation of mutations due to the error-prone repair of the DSBs created by the L1 endonuclease. The direct health implication of this discovery would be L1 contribution to mammalian aging and/or age- associated diseases such as cancer. Due to the constant improvement of the health care there is a growing population of older people that is more susceptible to age-associated diseases. Understanding of the molecular mechanisms of aging would contribute to our potential to prevent the onset of aging or age- associated diseases.

描述（由申请人提供）：本提案的目标是了解细胞对 L1 活性反应的机制，评估 L1 诱导的突变及其对 DNA 损伤和相关衰老的贡献，以确定这种贡献是否随着年龄的增长而增加，并找出个体之间这种贡献的潜在差异。这些目标很重要，因为现有数据表明，L1 编码的 DNA 核酸内切酶造成的双链断裂 (DSB) 形式的 DNA 损伤可能比该元件通过插入诱变对基因组造成的损伤大得多。我们在许多体细胞中检测到内源性 L1 表达。因此，这种类型的 DNA 损伤会对整个生物体产生影响，而不仅仅是其后代。我们还希望解决 L1 对人类干细胞 DNA 损伤和相关衰老的影响。在这些研究中，我们将通过正常细胞系中的蛋白质印迹分析、g-H2AX 焦点染色和 COMET 测定来操纵 L1 表达水平，并将 L1 活性与由此产生的 DNA 损伤相关联。我们将使用报告基因测定来量化 L1 元件的致突变潜力。我们将使用培养的原代细胞模型来确定 L1 加速体细胞和干细胞衰老的潜力。据报道，L1 元件造成 DNA 损伤的能力及其在许多人体组织中的内源性表达，从根本上改变了我们对 L1 表达的重要性及其对宿主健康影响的理解。该项目旨在确定体细胞和干细胞中持续的低水平 L1 表达是否会由于 L1 核酸内切酶产生的 DSB 容易出错的修复而导致突变的稳定积累。这一发现对健康的直接影响是 L1 对哺乳动物衰老和/或癌症等与年龄相关的疾病的贡献。由于医疗保健的不断改善，老年人口不断增加，他们更容易患与年龄相关的疾病。了解衰老的分子机制将有助于我们预防衰老或与年龄相关的疾病的发生。