Oxidative DNA damage repair and parp 1 and parp 2 expression in Epstein-Barr virus-immortalized B lymphocyte cells from young subjects, old subjects, and centenarians

Oxidative DNA damage has been implicated in the aging process and in some of its features such as telomere shortening and replicative senescence. Poly(ADP-ribosyl)ation is involved in many molecular and cellular processes, including DNA damage detection and repair, chromatin modification, transcription, and cell death pathways. We decided to examine the behavior of poly(ADP-ribosyl)ation in centenarians, i.e., those subjects who represent the best example of longevity having reached a very advanced age avoiding the main age-associated diseases. In this study we investigated the relationship between DNA repair capacity and poly(ADP-ribose) polymerase activity in Epstein-Barr virus-immortalized B lymphocyte cell lines from subjects of three different groups of age, including centenarians. Our data show that cells from centenarians have characteristics typical of cells from young people both in their capability of priming the mechanism of repair after H₂O ₂ sublethal oxidative damage and in poly(ADP-ribosyl)ation capacity, while in cells from old subjects these phenomena are delayed or decreased. Moreover, cells from old subjects show a constitutive expression level of both parp 1 and parp 2 genes reduced by a half, together with a reduced presence of modified PARP 1 and other poly(ADP-ribosyl)ated chromatin proteins in comparison to cells from young subjects and centenarians. Our data support the hypothesis that this epigenetic modification is an important regulator of the aging process in humans and it appears to be rather preserved in healthy centenarians, the best example of successful aging.