In conclusion, we found that the genetic variability of UCP genes affects human longevity. This finding is in agreement with previous data showing that energy storage and expenditure have a key role in survival at old age and support the Uncoupling-to-survive hypothesis. Although this hypothesis was initially based on the possible effects of UCPs on the oxidative stress, the most recent data have emphasized the impact of UCP variations on the metabolic efficiency. It is then likely that the impact of UCPs’ gene variation on longevity is due to the complexity of these functions rather than the sole effect of oxidative stress. On the other hand, due to the presence of different UCP genes, each active in specific tissues, further analyses will be necessary to understand the specific role of the uncoupling process in different tissues and, consequently, in correlation with differing metabolism and, possibly, nutrients.

Supporting Information

Table S1 Genotypic and allelic frequencies in the analyzed sample by group.

Haplotype analysis confirmed the single SNP analyses, and highlighted the importance of the entire UCP2-UCP3 locus in human aging and longevity. In fact, one finding of interest emerging from this analysis is that the UCP2-rs659366 (-866 G/A), which was uninformative to single-locus analysis, seemed instead to be effective in modulating the aging process. In particular the rs659366G allele appeared to exert a modest beneficial effect on human survival. Indeed, the presence of the rs659366G allele reduced the negative effect of the rs659366C-rs15763C haplotype, while it increased the

Author Contributions

Conceived and designed the experiments: GR GP. Performed the experiments: PC. Analyzed the data: FDR AM. Wrote the paper: GR GP. Read and discussed the final form of the manuscript: GR PC FDR AM GP.

References

Fridell YW, Sa´nchez-Blanco A, Silvia BA, Helfand SL (

) Functional characterization of a Drosophila mitochondrial uncoupling protein. J Bioenerg Biomembr

:

–

Fridell YW, Hoh M, Kre´neisz O, Hosier S, Chang C, et al. (

) Increased uncoupling protein (UCP) activity in Drosophila insulin-producing neurons attenuates insulin signaling and extends lifespan. Ageing

:

–

Speakman JR, Talbot DA, Selman C, Snart S, M

aren JS, et al. (

) Uncoupled and surviving: individual mice with high metabolism have greater mitochondrial uncoupling and live longer. Ageing Cell

:

–

Conti B, Sanchez-Alavez M, Winsky-Sommerer R, Morale MC, Lucero J, et al. (

) Transgenic mice with a reduced core body temperature have an increased life span. Science

:

–

Andrews ZB, Horvath TL (

) Uncoupling protein-

regulates lifespan in mice. Am J Physiol Endocrinol Metab

(E):

–

Caldeira da Silva CC, Cerqueira FM, Barbosa LF, Medeiros MH, Kowaltowski AJ (

) Mild mitochondrial uncoupling in mice affects energy metabolism, redox balance and longevity. Ageing Cell

:

–

Bevilacqua L, Ramsey JJ, Hagopian K, Weindruch R, Harper ME (

) Long- term caloric restriction increases UCP

content but decreases proton leak and reactive oxygen species production in rat skeletal muscle mitochondria. Am J Physiol Endocrinol Metab

(E):

–

M

onald RB, Walker KM, Warman DB, Griffey SM, Warden CH, et al. (

) Characterization of survival and phenotype throughout the life span in UCP

/UCP

genetically altered mice. Exp Gerontol

:

–

Li Y, Maedler K, Shu L, Haataja L (

) UCP-

and UCP-

proteins are differentially regulated in pancreatic beta-cells. PL

One

: e

Salopuro T, Pulkkinen L, Lindstro¨m J, Kolehmainen M, Tolppanen AM, et al. (

) Variation in the UCP

and UCP

genes associates with abdominal obesity and serum lipids: the Finnish Diabetes Prevention Study. BMC Med Genet

:

Jia JJ, Zhang X, Ge CR, Jois M (

) The polymorphisms of UCP

and UCP

genes associated with fat metabolism, obesity and diabetes. Obes Rev

:

–

Crocco P, Montesanto A, Passarino G, Rose G (

) A common polymorphism in the UCP

promoter influences hand grip strength in elderly people. Biogerontology

(

):

–

Rose G, Crocco P, D’Aquila P, Montesanto A, Bellizzi D, et al. (

) Two variants located in the upstream enhancer region of human UCP

gene affect gene expression and are correlated with human longevity. Exp Gerontol [Epub ahead of print].

Passarino G, Montesanto A, Dato S, Giordano S, Domma F, et al. (

) Sex and age specificity of susceptibility genes modulating survival at old age. Hum Hered

:

–

Wigginton JE, Cutler DJ, Abecasis GR (

) A note on exact tests of Hardy- Weinberg equilibrium. Am J Hum Genet

:

–

Freidlin B, Zheng G, Li Z, Gastwirth JL (

) Trend tests for case-control studies of genetic markers: power, sample size and robustness. Hum Hered

:

–

Zang Y, Fung WK (

) Robust tests for matched case-control genetic association studies. BMC Genet

:

Zang Y, Fung WK, Zheng G (

) Simple algorithms to calculate asymptotic null distribution for robust tests in case-control genetic association studies in R. Journal of Statistical Software

:

–

So HC, Sham PC (

) Robust Association Tests Under Different Genetic Models, Allowing for Binary or Quantitative Traits and Covariates. Behav Genet

:

–

Barrett JC, Fry B, Maller J, Daly MJ (

) Haploview: analysis and visualization of LD and haplotype maps. Bioinformatics

:

–

Schaid DJ, Rowland CM, Tines DE, Jacobson RM, Poland GA (

) "Score tests for association of traits with haplotypes when linkage phase is ambiguous. " Amer J Hum Genet

:

–

Calle ML, Urrea V, Vellalta G, Malats N, Steen KV (

) Improving strategies for detecting genetic patterns of disease susceptibility in association studies. Stat Med

(

):

–

Bouchard C, Perusse L, Chagnon YC, Warden C, Ricquier D (

) Linkage between markers in the vicinity of the uncoupling protein

gene and resting metabolic rate in humans. Hum Mol Genet

:

–

Fleury C, Neverova M, Collins S, Raimbault S, Champigny O, et al. (

) Uncoupling protein-