title: Oxidative DNA damage as a marker of aging in WI-38 human fibroblasts.
abstract: Cause-effect relationships between oxidative stress, DNA damage and aging were investigated in WI-38 human diploid fibroblasts at 21, 41 or 58 population doublings (PDs), corresponding to young, middle age or old fibroblasts, respectively. Oxidative DNA damage was evaluated by immunohistochemical detection of 8-hydroxy-2'deoxyguanosine (8-OHdG) adducts or by single cell microgel electrophoresis (COMET assay). Aging was evaluated by growth rate, senescence-associated-beta-galactosidase (SA-beta galactosidase) activity, cell cycle distribution, and expression of p21. Our results demonstrate that (i) oxidative DNA damage is proportional to the age of cells (ii) DNA damage in old/58 PDs cells reflects both an increased susceptibility to oxidative stress, induced by acute exposure to sub-lethal concentrations of hydrogen peroxide (H(2)O(2)), and a reduced efficiency of repair mechanisms. We also show that mild chronic oxidative stress, induced by prolonged exposure to 5 microM H(2)O(2), accelerates aging in fibroblasts. In fact, this treatment increased 8-OHdG levels, SA-beta-galactosidase activity, and G0/G1 cell cycle arrest in middle age/41 PDs, making them similar to H(2)O(2)-untreated old/58 PDs cells. Although other mechanisms may concur in mediating the effects of H(2)O(2), these results lend support to the concept that oxidative stress may be a key determinant of aging. Measurements of oxidative DNA damage might therefore be exploited as reliable marker of cellular aging.
authors.affiliation: School of Medicine, Institute of General Pathology and Giovanni XXIII Cancer Research Center, Catholic University of Sacred Heart, L. go F. Vito 1, 00168 Rome, Italy. fwolf@rm.unicatt.it
authors.forename: Federica I
authors.initials: FI
authors.lastname: Wolf
authors.forename: Angela
authors.initials: A
authors.lastname: Torsello
authors.forename: Valeria
authors.initials: V
authors.lastname: Covacci
authors.forename: Silvia
authors.initials: S
authors.lastname: Fasanella
authors.forename: Micaela
authors.initials: M
authors.lastname: Montanari
authors.forename: Alma
authors.initials: A
authors.lastname: Boninsegna
authors.forename: Achille
authors.initials: A
authors.lastname: Cittadini
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D015415:Biomarkers; D002453:Cell Cycle / Q000187:drug effects; D002460:Cell Line; D016922:Cellular Senescence / Q000502:physiology*; D004249:DNA Damage; D004260:DNA Repair; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D015415:Biomarkers; D000080242:8-Hydroxy-2'-Deoxyguanosine; D006861:Hydrogen Peroxide; D001616:beta-Galactosidase; D003849:Deoxyguanosine