Discussion:
The minor allele of rs275653 is associated with longevity in Japanese and Italian populations.
The GG genotype is enriched in both centenarians' groups from Italy and Japan compared to controls.
The rs275653 SNP affects AT R expression on peripheral blood leukocytes.
The GG genotype of rs275653 is associated with lower blood pressure in centenarians.Genetically diverse population. 

Discussion: 

In this study, we have identified a region in the promoter of the human AGTR1 that is associated with extreme longevity. Studies on a test group of Italian centenarians and controls provided evidence of a significant association between SNP variants of AGTR1 and human lifespan. Although studies in short-lived organisms and in human isolated populations with exceptional lifespan have clearly shown that genes play a role in longevity, the specific genetic variants involved are still largely unknown. Evidences in mammals point to a role of genes involved in the major causes of death, i.e. cardiovascular disease, cancer, and brain disease. 

The vasoactive hormone AngII has been involved in organ senescence, and in previous studies, we demonstrated that disruption of the mouse gene encoding for AT R 1A markedly prolonged animal lifespan (Benigni et al. 2009) and protected mice from vascular and cardiac injury.

Our findings are in line with the hypothesis that SNP variations in the AGTR1 promoter can influence protein levels of the corresponding receptor, and that a region including or linked to the AGTR1 promoter could play a role in modulating local RAS system. Since our sequencing-based screening study was confined to the proximal portion of AGTR1 promoter and to coding regions and intron/exon boundaries, the possibility that rs275653 and the linked rs422858 and rs2307085 are in linkage disequilibrium to variants in other regulatory elements in the promoter or in introns cannot be excluded.

Here we demonstrate that in an Italian cohort, the C-variant of rs422858 and the linked G-variant of rs275653 are overrepresented in centenarians with an OR of 4.55 according to the recessive model, in line with what should be expected for a polygenic trait like longevity. Replication of rs275653 genotyping in Japanese cohort, characterized by a large number of centenarians and semi-supercentenarians of homogeneous ethnic origin, confirmed an enrichment of the G-allele in centenarians and its association to longevity according to the recessive model. Combined analyses sustained the association at genotype level. Data of European and Japanese populations from 1000 Genomes and from HapMap databases as well as our results on the Italian group demonstrate that rs275653 is in complete linkage disequilibrium with rs422858. The absence of the rs275653 GG genotype in our Japanese controls diverges from the data of the small cohort of Japanese subjects in 1000 Genomes database (rs275653 GG genotype: one over 90 subjects). However, comparison of the genotype prevalence in Japanese population of 1000 Genomes and in our Japanese controls failed to evidence any statistical difference both at genotype and at allele level.

The variant of rs422858 belongs to an E-box element which is lost in the presence of the minor allele. Supportive evidence to our genetic data comes from ex vivo findings indicating that the longevity-associated variants have functional consequences on the expression of the corresponding receptor protein on the surface of circulating cells. Indeed, by FACS experiments, we demonstrated that PMNs of subjects homozygous for the minor rs275653 allele (and consequently for the C-variant of rs422858) had a significantly lower percentage of AT R-positive cells with respect to subjects heterozygous and homozygous for the major allele. A similar difference was observed when the CD16+ PMN fraction was analyzed. Consistently, previously reported transfection experiments in adrenal cortical and in vascular smooth muscle cells (Kumar et al. 2005) documented that reporter constructs containing the A rs422858 variant had higher promoter activity than constructs with the minor C-variant, suggesting that this SNP could affect the levels of AT R gene transcription.

Fig. 3 Blood pressure in Italian and Japanese centenarians according to rs275653 genotype. Data are represented as mean SEM. a Diastolic blood pressure was significantly lower in centenarians with GG genotype as compared to those AA genotype (additive model, P00.031) or to centenarians with AA and AG genotypes (recessive model, P00.040). G-allele was also associated with reduced DBP (P00.037). SBP and MAP (b and c, respectively) were statistically different in centenarians carrying the rs275653 G-allele (P00.046 and P00.042, respectively).

In both Italian and Japanese centenarians, we observed a statistically significant decreased systolic blood pressure in homozygous for GG rs275653 genotype suggesting that this polymorphism might influence blood pressure. In control subjects, we observed a reduction of SBP in subject homozygous for GG genotype; however, this difference was not statistically significant. It is likely that the wide range of age in the control population may have masked the association between the G-allele ofResults indicate that genetic AGTR1 variants leading to reduced receptor expression may contribute to prolonging human lifespan. These findings are of particular relevance as they disclose AT R as a peculiar pharmacological target for the prevention and treatment of disabilities and diseases that occur with allelic variations in AGTR1 promoter, including the rs422858 major allele, have been associated with hypertension in Caucasian women (Kumar et al. 2005). Very recently, SNPs in the AGTR1 promoter have been associated with the risk of hypertension in Mexicans (Martinez-Rodriguez et al. 2011) and salt sensitivity.