New polymorphisms in the human poly(ADP-ribose) polymerase-1 coding sequence: lack of association with longevity or with increased cellular poly(ADP-ribosyl)ation capacity.

Poly(ADP-ribose) polymerase-1 (PARP-1) encoded by the PARP-1 gene, is a ubiquitous and abundant DNA-binding protein involved in the cellular response to various genotoxic agents. In a previous study we showed that maximal oligonucleotide-stimulated poly(ADP-ribosyl)ation was significantly higher in permeabilised lymphoblastoid cell lines from a French population of centenarians compared with controls aged 20-70 years, supporting the notion that longevity is associated with a genetically determined, high poly(ADP-ribosyl)ation capacity. Here, we describe four new genetic polymorphisms, three of which represent silent nucleotide variants (C402T, T1011C, G1215A), and one of which leads to a valine762-to-alanine exchange (T2444C). We undertook an association study between two of these polymorphisms and human longevity or poly(ADP-ribosyl)ation capacity in permeabilised lymphoblastoid cells. By analysing 648 DNA samples from a French population (324 centenarians and 324 controls) by fluorescent-allele-specific PCR, we showed the absence of any significant enrichment of any of the genotypes in the study of centenarians versus controls. Furthermore, we studied genotype distributions from individuals who had previously been tested for poly(ADP-ribosyl)ation capacity. None of the genotype combinations at any polymorphic site studied could be related to a high or low level of poly(ADP-ribosyl)ation capacity. Together, these results strongly suggest that the longevity-related differences in the poly(ADP-ribosyl)ation capacity of human lymphoblastoid cell lines cannot be explained by genetic polymorphisms in the PARP-1 coding sequence and that other mechanisms have to be considered as potential regulators of specific poly(ADP-ribosyl)ation capacity.

Lack of association between human longevity and genetic polymorphisms in drug-metabolizing enzymes at the NAT2, GSTM1 and CYP2D6 loci.

In the present study, the possible role of genetic polymorphism of three drug-metabolizing enzymes, debrisoquine/sparteine hydroxylase (CYP2D6), glutathione S-transferase mu (GSTM1), and N-acetyltransferase (NAT2), as a putative genetic component of human longevity, was explored. A total of 817 DNA samples from a centenarian and a control (20-70 years) population was subjected to PCR-coupled RFLP methods. Subjects were genotyped for the CYP2D6*3 (A2637 deletion) and CYP2D6*4 (G1934A transition) alleles, for four mutations of NAT2 [namely, NAT2*5A (C481T), NAT2*6A (G590A), NAT2*7A (G857A), and NAT2*14A (G191A)], and for the presence or absence of GSTM1 gene deletion. No significant difference was found at these three loci between centenarian and control subjects with respect to allelic variant frequencies, genotype distributions or predicted phenotypes deduced from genotype combinations. By comparing the distribution of combined genotypes for the polymorphisms tested at the CYP2D6, NAT2, and GSTM1 loci, none of the predicted phenotypes concerning debrisoquine hydroxylase extensive-metabolizer or poor-metabolizer phenotypes, slow or fast N-acetylation capacities, and active or defective glutathione S-transferase, could be correlated with human longevity, alone or in combination.