The contribution of DNA interstrand crosslinks to aging

DNA链间交联对衰老的贡献

• 批准号: 7494964
• 负责人: Laura Jane Niedernhofer
• 金额: $ 52.61万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-10 至 2012-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7494964
• 关键词: 2-chloroethylamine; 8-MOP; Affect; Age; Aging; Apoptosis; Biological; Biological Models; Body Weight decreased; Bone Marrow; CCL4 gene; Cadmium; Cardiovascular Diseases; Cell Aging; Cell Survival; Cells; Cessation of life; Chromosome abnormality; Class; Complex; Condition; Coupled; DNA; DNA Crosslinking; DNA Crosslinking Agent; DNA Damage; DNA Interstrand Crosslinking; DNA lesion; Disease; Dose; Elderly; End Point; Engineering; Environment; Environmental Exposure; Epidermis; Exposure to; Ficusin; Fracture; Frequencies; Genomic Instability; Genotoxic Stress; Health; Human; In Vitro; Individual; Kidney; Lesion; Life; Lipid Peroxidation; Liver; Malignant Neoplasms; Measures; Mechlorethamine; Membrane; Methoxsalen; Molecular; Mus; Mutagens; Mutation; Nerve Degeneration; Nucleotide Excision Repair; Numbers; Pathology; Pharmaceutical Preparations; Phenotype; Plants; Predisposition; Prevention; Progeria; Psoralens; Rate; Reactive Oxygen Species; Research; Research Personnel; Risk; Severities; Skin; Skin Aging; Source; Symptoms; Syndrome; Testing; Week; Wild Type Mouse; Work; aging population; angelicin; body system; cohort; crosslink; cytotoxic; cytotoxicity; demographics; disorder risk; driving force; early onset; endonuclease; environmental agent; functional loss; in vivo; photoactivation; programs; repaired; research study; response; sarcopenia

DESCRIPTION (provided by applicant): Aging is characterized by loss of functional reserve, placing the elderly at increased risk of numerous diseases. Identifying the driving force behind this functional loss is essential for maintaining a healthy populace. Recent evidence from our lab and others implicates DNA damage as a cause of aging. This implies a strong environmental component to aging. The long term objective of this research is to understand the molecular mechanism by which DNA damage promotes aging. This coupled with identifying environmental causes of genotoxic stress will greatly facilitate prevention of age-associated diseases. ERCC1-XPF is an endonuclease required for repair of bulky monoadducts via nucleotide excision repair (NER) and DNA interstrand crosslinks (ICLs) via a distinct mechanism. Deletion of ERCC1-XPF in the mouse causes early onset aging. These mice therefore offer a unique, rapid and sensitive model system for discovering which genotoxins promote aging and how they do so. The phenotype of the Erccl mice cannot be attributed to loss of NER. Thus our working hypothesis is that rapid aging in ERCC1-XPF deficient mice is caused by their inability to repair ICLs and therefore a consequence of endogenous ICLs which are cytotoxic. To test this, the investigators engineered mice hypomorphic for ERCC1-XPF which age over the course of months, permitting interventional studies. These mice will be exposed to DNA crosslinking drugs and environmental agents that promote lipid peroxidation (LPO), a likely source of endogenous ICLs, to determine if these exposures exacerbate the progeroid symptoms of the mice. The investigators discovered a human progeria caused by mutation of XPF. Thus identifying the cause of rapid aging in ERCC1-XPF-deficient mice will have direct implications for human health. The specific aims of this project are: Aim I: To define the cellular response of ERCCl-XPF-deficient cells to DNA ICLs and LPO. ERCCl-XPF-deficient cells will be exposed to 8-MOP or angelicin, plant-derived psoralens. Photoactivation of 8-MOP induces ICLs and monoadducts, whereas angelicin produces only monoadducts. Cell survival, cellular senescence, apoptosis, mutation frequency and chromosomal aberrations will be measured. If our hypothesis is correct then, 8-MOP will be significantly more cytotoxic than angelicin under conditions where an equal number of DNA lesions are induced. ERCCl-XPF-deficient cells will also be exposed to cadmium, an environmental agent that promotes LPO, to determine if LPO elicits the same cellular response as ICLs. Aim II: To directly test the hypothesis that unrepaired DNA ICLs promote aging. ERCC1-XPF hypomorphic mice will be chronically exposed to the crosslinking agent mechlorethamine. A second cohort will be exposed to 2-chloroethylamine (which induces structurally related monoadducts but not ICLs) using a dose that induces the same number of lesions as mechlorethamine. If our hypothesis is correct, mechlorethamine, but not 2-chloroethylamine, will exacerbate the progeria in these mice. Results will be confirmed by comparing skin aging in response to topical 8-MOP versus angelicin plus UV-A in mice genetically deleted for ERCC1-XPF in the skin only. Aim III: To determine if lipid peroxidation (LPO) promotes aging in mice with defective ICL repair. LPO is caused by oxygen radical damage to membranes and yields products able to crosslink DNA. We hypothesize that LPO is a source of ICLs that contribute to the phenotype of the Erccl mice. LPO will be induced in ERCCl-XPF-deficient mice via exposure to CCL4 or cadmium. If our hypothesis is correct, Erccl mice will be hypersensitive to LPO compared to wild type mice and LPO will exacerbate their progeria. Results from these experiments will indicate if LPO promotes aging and if so, whether it does so by inducing DNA damage. These experiments will also reveal if two common industrial exposures promote aging.

描述（由申请人提供）： 衰老的特点是功能储备的丧失，使老年人患多种疾病的风险增加。确定这种功能丧失背后的驱动力对于维持健康的人群至关重要。我们实验室和其他实验室最近的证据表明，DNA损伤是衰老的一个原因。这意味着老化有很强的环境因素。这项研究的长期目标是了解DNA损伤促进衰老的分子机制。这与确定遗传毒性压力的环境原因相结合，将大大有助于预防与年龄相关的疾病。 ERCC 1-XPF是一种核酸内切酶，通过核苷酸切除修复（NER）和DNA链间交联（ICL）通过不同的机制修复大体积单加合物。ERCC 1-XPF基因缺失导致小鼠早发性衰老因此，这些小鼠提供了一个独特的，快速和敏感的模型系统，用于发现哪些基因毒素促进衰老以及它们如何做到这一点。 Erccl小鼠的表型不能归因于NER的丧失。因此，我们的工作假设是，ERCC 1-XPF缺陷小鼠的快速衰老是由于它们不能修复ICL，因此是内源性ICL的结果，这些ICL是细胞毒性的。为了验证这一点，研究人员设计了ERCC 1-XPF亚型小鼠，这些小鼠在几个月的时间内老化，允许进行干预性研究。这些小鼠将暴露于DNA交联药物和促进脂质过氧化（LPO）（内源性ICL的可能来源）的环境因子，以确定这些暴露是否加剧小鼠的早衰症状。研究人员发现了一种由XPF突变引起的人类早衰症。因此，确定ERCC 1-XPF缺陷小鼠快速衰老的原因将对人类健康产生直接影响。本项目的具体目的是：目的I：确定ERCC 1-XPF缺陷细胞对DNA ICL和LPO的细胞反应。ERCC 1-XPF缺陷细胞将暴露于8-MOP或当归素，植物来源的当归。光活化8-MOP诱导ICL和单加合物，而当归素只产生单加合物。将测量细胞存活、细胞衰老、细胞凋亡、突变频率和染色体畸变。如果我们的假设是正确的，那么，在诱导相同数量的DNA损伤的条件下，8-MOP的细胞毒性将显著高于当归素。ERCCl-XPF缺陷细胞也将暴露于镉，一种促进LPO的环境剂，以确定LPO是否引起与ICL相同的细胞反应。目的二：直接验证未修复的DNA ICLs促进衰老的假设。ERCC 1-XPF亚型小鼠将长期暴露于交联剂氮芥。第二个队列将暴露于2-氯乙胺（诱导结构相关的单加合物，但不诱导ICL），使用的剂量与氮芥诱导的病变数量相同。如果我们的假设是正确的，氮芥，而不是2-氯乙胺，将加剧这些小鼠的早衰症。结果将通过在仅在皮肤中遗传缺失ERCC 1-XPF的小鼠中比较响应于局部8-MOP与当归素加UV-A的皮肤老化来证实。 目的III：确定脂质过氧化（LPO）是否促进ICL修复缺陷小鼠的衰老。LPO是由氧自由基对膜的损伤引起的，并产生能够交联DNA的产物。我们假设LPO是导致Erccl小鼠表型的ICL的来源。通过暴露于CCL 4或镉，在ERCCl-XPF缺陷小鼠中诱导LPO。如果我们的假设是正确的，那么Erccl小鼠与野生型小鼠相比将对LPO过敏，并且LPO将加剧它们的早衰症。这些实验的结果将表明LPO是否会促进衰老，如果是的话，它是否会通过诱导DNA损伤来促进衰老。这些实验还将揭示两种常见的工业暴露是否会促进衰老。