The contribution of DNA interstrand crosslinks to aging

DNA链间交联对衰老的贡献

基本信息

批准号：
7338450
负责人：
Laura Jane Niedernhofer
金额：
$ 48.17万
依托单位：
UNIVERSITY OF PITTSBURGH AT PITTSBURGH
依托单位国家：
美国
项目类别：
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/7338450
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

项目摘要

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民众健康至关重要。我们实验室和其他实验室的最新证据表明 DNA 损伤是衰老的一个原因。这意味着衰老有很强的环境因素。这项研究的长期目标是了解 DNA 损伤促进衰老的分子机制。再加上确定遗传毒性应激的环境原因将极大地促进与年龄相关的疾病的预防。 ERCC1-XPF 是一种核酸内切酶，通过独特的机制通过核苷酸切除修复 (NER) 和 DNA 链间交联 (ICL) 修复庞大的单加合物。小鼠中 ERCC1-XPF 的缺失会导致早发衰老。因此，这些小鼠提供了一种独特、快速且灵敏的模型系统，用于发现哪些基因毒素会促进衰老以及它们是如何促进衰老的。 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，ERCC1-XPF 缺陷小鼠的快速衰老是由于它们无法修复 ICL 造成的，因此是具有细胞毒性的内源性 ICL 的结果。为了测试这一点，研究人员设计了 ERCC1-XPF 低等态小鼠，这些小鼠会在数月内老化，从而允许进行介入研究。这些小鼠将接触 DNA 交联药物和促进脂质过氧化 (LPO) 的环境剂（LPO 是内源性 ICL 的可能来源），以确定这些接触是否会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 ERCC1-XPF 缺陷小鼠快速衰老的原因将对人类健康产生直接影响。该项目的具体目标是：目标 I：定义 ERCCl-XPF 缺陷细胞对 DNA ICL 和 LPO 的细胞反应。 ERCCl-XPF缺陷细胞将暴露于8-MOP或当归素、植物来源的补骨脂素。 8-MOP 的光活化诱导 ICL 和单加合物，而当归素仅产生单加合物。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。如果我们的假设正确，那么在诱导相同数量的 DNA 损伤的条件下，8-MOP 的细胞毒性将明显高于当归素。 ERCCl-XPF 缺陷细胞还将暴露于镉（一种促进 LPO 的环境剂），以确定 LPO 是否引发与 ICL 相同的细胞反应。目标 II：直接检验未修复的 DNA ICL 会促进衰老的假设。 ERCC1-XPF 亚效型小鼠将长期暴露于交联剂氮芥。第二组将暴露于 2-氯乙胺（它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相同数量的损伤。如果我们的假设正确，那么二甲氯乙胺（而不是 2-氯乙胺）会加剧这些小鼠的早衰症。结果将通过比较仅皮肤中 ERCC1-XPF 基因缺失的小鼠对局部 8-MOP 与当归素加 UV-A 的皮肤老化反应来证实。目标 III：确定脂质过氧化 (LPO) 是否会促进 ICL 修复缺陷小鼠的衰老。 LPO 是由氧自由基对膜造成的损伤引起的，并产生能够交联 DNA 的产物。我们假设 LPO 是 ICL 的来源，有助于 Erccl 小鼠的表型。通过暴露于 CCL4 或镉，ERCCl-XPF 缺陷小鼠将诱导 LPO。如果我们的假设是正确的，与野生型小鼠相比，Erccl 小鼠将对 LPO 过敏，并且 LPO 会加剧它们的早衰。这些实验的结果将表明 LPO 是否会促进衰老，如果是的话，它是否是通过诱导 DNA 损伤来实现的。这些实验还将揭示两种常见的工业暴露是否会促进衰老。