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.

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Research Project (R01)
Project #
5R01ES016114-05
Application #
8097589
Study Section
Special Emphasis Panel (ZES1-JAB-C (R1))
Program Officer
Mcallister, Kimberly A
Project Start
2007-09-10
Project End
2012-06-30
Budget Start
2011-07-01
Budget End
2012-06-30
Support Year
5
Fiscal Year
2011
Total Cost
$377,836
Indirect Cost
Name
University of Pittsburgh
Department
Genetics
Type
Schools of Medicine
DUNS #
004514360
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
Zhao, Jing; Li, Xuesen; McGowan, Sara et al. (2015) NF-?B activation with aging: characterization and therapeutic inhibition. Methods Mol Biol 1280:543-57
Tilstra, Jeremy S; Gaddy, Daniel F; Zhao, Jing et al. (2014) Pharmacologic IKK/NF-?B inhibition causes antigen presenting cells to undergo TNF? dependent ROS-mediated programmed cell death. Sci Rep 4:3631
Vaezi, Alec E; Bepler, Gerold; Bhagwat, Nikhil R et al. (2014) Choline phosphate cytidylyltransferase-? is a novel antigen detected by the anti-ERCC1 antibody 8F1 with biomarker value in patients with lung and head and neck squamous cell carcinomas. Cancer 120:1898-907
Nasto, Luigi A; Ngo, Kevin; Leme, Adriana S et al. (2014) Investigating the role of DNA damage in tobacco smoking-induced spine degeneration. Spine J 14:416-23
Nidadavolu, Lolita S; Niedernhofer, Laura J; Khan, Saleem A (2013) Identification of microRNAs dysregulated in cellular senescence driven by endogenous genotoxic stress. Aging (Albany NY) 5:460-73
Nasto, Luigi A; Wang, Dong; Robinson, Andria R et al. (2013) Genotoxic stress accelerates age-associated degenerative changes in intervertebral discs. Mech Ageing Dev 134:35-42
Lavasani, Mitra; Lu, Aiping; Thompson, Seth D et al. (2013) Isolation of muscle-derived stem/progenitor cells based on adhesion characteristics to collagen-coated surfaces. Methods Mol Biol 976:53-65
Chen, Qian; Liu, Kai; Robinson, Andria R et al. (2013) DNA damage drives accelerated bone aging via an NF-?B-dependent mechanism. J Bone Miner Res 28:1214-28
Vo, Nam; Niedernhofer, Laura J; Nasto, Luigi Aurelio et al. (2013) An overview of underlying causes and animal models for the study of age-related degenerative disorders of the spine and synovial joints. J Orthop Res 31:831-7
Karakasilioti, Ismene; Kamileri, Irene; Chatzinikolaou, Georgia et al. (2013) DNA damage triggers a chronic autoinflammatory response, leading to fat depletion in NER progeria. Cell Metab 18:403-15

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