Sirtuins are not conserved longevity genes
Charles Brenner
Sirtuins are not conserved longevity genes
It is central to biology that sequence conservation suggests functional conservation. Animal longevity is an emergent property of selected traits that integrates capacities to perform physical and mental functions after reproductive maturity. Though the yeast SIR2 gene was nominated as a longevity gene based on extended replicative longevity of old mother cells, this is not a selected trait: SIR2 is selected against in chronological aging and the direct targets of SIR2 in replicative lifespan are not conserved. Though it would be difficult to imagine how a gene that advantages 1 in 5 million yeast cells could have anticipated causes of aging in animals, overexpression of SIR2 homologs was tested in invertebrates for longevity. Because artifactual positive results were reported years before they were sorted out and because it was not known that SIR2 functions as a pro-aging gene in yeast chronological aging and in flies subject to amino acid deprivation, a global pursuit of longevity phenotypes was driven by a mixture of framing bias, confirmation bias, and hype. Review articles that propagate these biases are so rampant that few investigators have considered how weak the case ever was for sirtuins as longevity genes. Acknowledging that a few positive associations between sirtuins and longevity have been identified after thousands of person-years and billions of dollars of effort, we review the data and suggest rejection of the notions that sirtuins (i) have any specific connection to lifespan in animals and (ii) are primary mediators of the beneficial effects of NAD repletion.
sirtuins / longevity / model organism / publication bias / resveratrol / nicotinamide adenine dinucleotide
[1] |
Monod , J . Chance and Necessity: Essay on the Natural Philosophy of Modern Biology. New York: Vantage, 1971.
|
[2] |
Haber JE. Mating-type genes and MAT switching in Saccharomyces cerevisiae. Genetics 2012; 191: 33- 64.
|
[3] |
Ivy JM, Klar AJ, Hicks JB. Cloning and characterization of four SIR genes of Saccharomyces cerevisiae. Mol Cell Biol 1986; 6: 688- 702.
|
[4] |
Rine J, Herskowitz I. Four genes responsible for a position effect on expression from HML and HMR in Saccharomyces cerevisiae. Genetics 1987; 116: 9- 22.
|
[5] |
Rine J. Ph.D. Thesis, University of Oregon, 1979.
|
[6] |
Perez-Martin J, Uria JA, Johnson AD. Phenotypic switching in Candida albicans is controlled by a SIR2 gene. EMBO J 1999; 18: 2580- 92.
|
[7] |
Freeman-Cook LL, Sherman JM, Brachmann CB et al. The Schizosaccharomyces pombe hst4(+) gene is a SIR2 homologue with silencing and centromeric functions.Mol Biol Cell 1999; 10: 3171- 86.
|
[8] |
Landry J, Sutton A, Tafrov ST et al. The silencing protein SIR2 and its homologs are NAD-dependent protein deacetylases. Proc Natl Acad Sci USA 2000; 97: 5807- 11.
|
[9] |
Smith JS, Brachmann CB, Celic I et al. A phylogenetically conserved NAD+-dependent protein deacetylase activity in the Sir2 protein family. Proc Natl Acad Sci USA 2000; 97: 6658- 63.
|
[10] |
Imai S, Armstrong CM, Kaeberlein M et al. Transcriptional silencing and longevity protein Sir2 is an NAD-dependent histone deacetylase. Nature 2000; 403: 795- 800.
|
[11] |
Sauve AA, Celic I, Avalos J et al. Chemistry of gene silencing: the mechanism of NAD+-dependent deacetylation reactions. Biochemistry 2001; 40: 15456- 63.
|
[12] |
Bell SD, Botting CH, Wardleworth BN et al. The interaction of Alba, a conserved archaeal chromatin protein, with Sir2 and its regulation by acetylation. Science 2002; 296: 148- 51.
|
[13] |
Denoth Lippuner A, Julou T, Barral Y. Budding yeast as a model organism to study the effects of age. FEMS Microbiol Rev 2014; 38: 300- 25.
|
[14] |
Sinclair DA, Guarente L. Extrachromosomal rDNA circles--a cause of aging in yeast. Cell 1997; 91: 1033- 42.
|
[15] |
Fabrizio P, Gattazzo C, Battistella L et al. Sir2 blocks extreme lifespan extension. Cell 2005; 123: 655- 67.
|
[16] |
Lin SJ, Defossez PA, Guarente L. Requirement of NAD and SIR2 for life-span extension by calorie restriction in Saccharomyces cerevisiae. Science 2000; 289: 2126- 8.
|
[17] |
Kaeberlein M, Kirkland KT, Fields S et al. Sir-independent life span extension by calorie restriction in yeast. PLoS Biol 2004; 2: 2E296.
|
[18] |
Guarente L. Sir2 links chromatin silencing, metabolism, and aging. Genes Dev 2000; 14: 1021- 6.
|
[19] |
Guarente L, Picard F. Calorie restriction--the SIR2 connection. Cell 2005; 120: 473- 82.
|
[20] |
Guarente L. Calorie restriction and SIR2 genes--towards a mechanism. Mech Ageing Dev 2005; 126: 923- 8.
|
[21] |
Wade N. Study spurs hope of finding way to increase human life. New York Times, 2003, A10.
|
[22] |
Ros-Rocher N, Perez-Posada A, Leger MM et al. The origin of animals: an ancestral reconstruction of the unicellular-to-multicellular transition. Open Biol 2021; 11: 200359.
|
[23] |
Rose MR. Evolutionary Biology of Aging. New York: Oxford University Press, 1994.
|
[24] |
Brenner C. Longevity lessons. Science 2022; 377: 718.
|
[25] |
Rose MR, Rauser CL, Benford G et al. Hamilton’s forces of natural selection after forty years. Evolution 2007; 61: 1265- 76.
|
[26] |
Johnson AA, Shokhirev MN, Shoshitaishvili B. Revamping the evolutionary theories of aging. Ageing Res Rev 2019; 55: 10947.
|
[27] |
Gems D. Evolution of sexually dimorphic longevity in humans. Aging (Albany NY) 2014; 6: 84- 91.
|
[28] |
Pavard S, E Metcalf C, Heyer E. Senescence of reproduction may explain adaptive menopause in humans: a test of the “mother” hypothesis. Am J Phys Anthropol 2008; 136: 194- 203.
|
[29] |
Rose MR. Laboratory evolution of postponed senescence in Drosophila melanogaster. Evolution 1984; 38: 1004- 10.
|
[30] |
Burke MK et al. Genome-wide analysis of a long-term evolution experiment with Drosophila. Nature 2010; 467: 587- 90.
|
[31] |
Giuliani C, Garagnani P, Franceschi C. Genetics of human longevity within an eco-evolutionary nature-nurture framework. Circ Res 2018; 123: 745- 72.
|
[32] |
Lin YJ, Seroude L, Benzer S. Extended life-span and stress resistance in the Drosophila mutant methuselah. Science 1998; 282: 943- 6.
|
[33] |
Song W, Ranjan R, Dawson-Scully K et al. Presynaptic regulation of neurotransmission in Drosophila by the g protein-coupled receptor methuselah. Neuron 2002; 36: 105- 119.
|
[34] |
de Mendoza A, Jones JW, Friedrich M. Methuselah/Methuselahlike G protein-coupled receptors constitute an ancient metazoan gene family. Sci Rep 2016; 6: 21801.
|
[35] |
Kimura KD, Tissenbaum HA, Liu Y et al. daf-2, an insulin receptor-like gene that regulates longevity and diapause in Caenorhabditis elegans. Science 1997; 277: 942- 6.
|
[36] |
Kenyon C, Chang J, Gensch E et al. A C. elegans mutant that lives twice as long as wild type. Nature 1993; 366: 461- 4.
|
[37] |
Bartke A, Brown-Borg H. Life extension in the dwarf mouse. Curr Top Dev Biol 2004; 63: 189- 225.
|
[38] |
Bartke A. Healthy aging: is smaller better? - a mini-review. Gerontology 2012; 58: 337- 43.
|
[39] |
Venter JC, Adams MD, Myers EW et al. The sequence of the human genome. Science 2001; 291: 1304- 51.
|
[40] |
Garber K. Beyond the Nobel Prize: cell cycle research offers new view of cancer. J Natl Cancer Inst 2001; 93: 1766- 8.
|
[41] |
Tissenbaum HA, Guarente L. Increased dosage of a sirgene extends lifespan in Caenorhabditis elegans. Nature 2001; 410: 227- 30.
|
[42] |
Gems D. Ageing. Yeast longevity gene goes public. Nature 2001; 410: 154- 5.
|
[43] |
Rogina B, Helfand SL. Sir2 mediates longevity in the fly through a pathway related to calorie restriction. Proc Natl Acad Sci USA 2004; 101: 15998- 6003.
|
[44] |
Chen D, Guarente L. SIR2: a potential target for calorie restriction mimetics. Trends Mol Med 2007; 13: 64- 71.
|
[45] |
Dali-Youcef N, Lagouge M, Froelich S et al. Sirtuins: the ‘magnificent seven’, function, metabolism and longevity. Ann Med 2007; 39: 335- 45.
|
[46] |
Sinclair DA, LaPlante MD. Lifespan: Why We Age—and Why We Don’t Have To. New York: Simon & Schuster, 2019.
|
[47] |
Burnett C, Valentini S, Cabreiro F et al. Absence of effects of Sir2 overexpression on lifespan in C. elegans and Drosophila. Nature 2011; 477: 482- 5.
|
[48] |
Viswanathan M, Guarente L. Regulation of Caenorhabditis elegans lifespan by sir-2.1 transgenes. Nature 2011; 477: E1- 2.
|
[49] |
Whitaker R, Faulkner S, Miyokawa R et al. Increased expression of Drosophila Sir2 extends life span in a dose-dependent manner. Aging (Albany NY) 2013; 5: 682- 91.
|
[50] |
Zhao Y, Wang H, Poole RJ et al. A fln-2 mutation affects lethal pathology and lifespan in C. elegans. Nat Commun 2019; 10: 5087.
|
[51] |
Newman BL, Lundblad JR, Chen Y et al. A Drosophila homologue of Sir2 modifies position-effect variegation but does not affect life span. Genetics 2002; 162: 1675- 85.
|
[52] |
Slade JD, Staveley BE. Extended longevity and survivorship during amino-acid starvation in a Drosophila Sir2 mutant heterozygote. Genome 2016; 59: 311- 8.
|
[53] |
Venz R, Pekec T, Katic I et al. End-of-life targeted degradation of DAF-2 insulin/IGF-1 receptor promotes longevity free from growth-related pathologies. Elife 2021; 10: 71335.
|
[54] |
Guarente L, Franklin H. Epstein lecture: sirtuins, aging, and medicine. N Engl J Med 2011; 364: 2235- 44.
|
[55] |
Fremont L. Biological effects of resveratrol. Life Sci 2000; 66: 663- 73.
|
[56] |
Renaud S, Gueguen R. The French paradox and wine drinking. In: Chadwick DJ, Goode JA (eds), Novartis Foundation Symposium 216-Alcohol and Cardiovascular Diseases: Alcohol and Cardiovascular Diseases. Novartis Foundation Symposium 216. Chichester, UK: John Wiley & Sons, Ltd, 2007, 208- 22.
|
[57] |
Ndlovu T, van Jaarsveld F, Caleb OJ. French and Mediterraneanstyle diets: contradictions, misconceptions and scientific facts-a review. Food Res Int 2019; 116: 840- 58.
|
[58] |
Howitz KT, Bitterman KJ, Cohen HY et al. Small molecule activators of sirtuins extend Saccharomyces cerevisiae lifespan. Nature 2003; 425: 191- 6.
|
[59] |
Finkel T. Ageing: a toast to long life. Nature 2003; 425: 132- 3.
|
[60] |
Hall SS. Longevity research. In vino vitalis? Compounds activate life-extending genes. Science 2003; 301: 1165.
|
[61] |
Lamming DW, Wood JG, Sinclair DA. Small molecules that regulate lifespan: evidence for xenohormesis. Mol Microbiol 2004; 53: 1003- 9.
|
[62] |
Howitz KT, Sinclair DA. Xenohormesis: sensing the chemical cues of other species. Cell 2008; 133: 387- 91.
|
[63] |
Baur JA, Sinclair DA. What is xenohormesis? Am J Pharmacol Toxicol 2008; 3: 152- 9.
|
[64] |
Kaeberlein M, McDonagh T, Heltweg B et al. Substratespecific activation of sirtuins by resveratrol. J Biol Chem 2005; 280: 17038- 45.
|
[65] |
Borra MT, Smith BC, Denu JM. Mechanism of human SIRT1 activation by resveratrol. J Biol Chem 2005; 280: 17187- 95.
|
[66] |
Pacholec M, Bleasdale JE, Chrunyk B et al. SRT1720, SRT2183, SRT1460, and resveratrol are not direct activators of SIRT1. J Biol Chem 2010; 285: 8340- 51.
|
[67] |
Wood JG, Rogina B, Lavu S et al. Sirtuin activators mimic caloric restriction and delay ageing in metazoans. Nature 2004; 430: 686- 9.
|
[68] |
Bass TM, Weinkove D, Houthoofd K et al. Effects of resveratrol on lifespan in Drosophila melanogaster and Caenorhabditis elegans. Mech Ageing Dev 2007; 128: 546- 52.
|
[69] |
Shaito A, Posadino AM, Younes N et al. Potential adverse effects of resveratrol: a literature review. Int J Mol Sci 2020; 21: 2084.
|
[70] |
Baur JA, Pearson KJ, Price NL et al. Resveratrol improves health and survival of mice on a high-calorie diet. Nature 2006; 444: 337- 42.
|
[71] |
Rodgers JT, Lerin C, Haas W et al. Nutrient control of glucose homeostasis through a complex of PGC-1alpha and SIRT1. Nature 2005; 434: 113- 8.
|
[72] |
Milne JC, Lambert PD, Schenk S et al. Small molecule activators of SIRT1 as therapeutics for the treatment of type 2 diabetes. Nature 2007; 450: 712- 6.
|
[73] |
Schmidt C. GSK/Sirtris compounds dogged by assay artifacts. Nat Biotechnol 2010; 28: 185- 6.
|
[74] |
Hubbard BP, Gomes AP, Dai H et al. Evidence for a common mechanism of SIRT1 regulation by allosteric activators. Science 2013; 339: 1216- 9.
|
[75] |
Cantó C, Jiang LQ, Deshmukh AS et al. Interdependence of AMPK and SIRT1 for metabolic adaptation to fasting and exercise in skeletal muscle. Cell Metab 2010; 11: 213- 9.
|
[76] |
Brenner C, Boileau AC. Pterostilbene raises low density lipoprotein cholesterol in people. Clin Nutr 2019; 38: 480- 1.
|
[77] |
Bordone L, Cohen D, Robinson A et al. SIRT1 transgenic mice show phenotypes resembling calorie restriction. Aging Cell 2007; 6: 759- 67.
|
[78] |
Imai S. Is Sirt1 a miracle bullet for longevity? Aging Cell 2007; 6: 735- 7.
|
[79] |
Pfluger PT, Herranz D, Velasco-Miguel S et al. Sirt1 protects against high-fat diet-induced metabolic damage. Proc Natl Acad Sci USA 2008; 105: 9793- 8.
|
[80] |
Banks AS, Kon N, Knight C et al. SirT1 gain of function increases energy efficiency and prevents diabetes in mice. Cell Metab 2008; 8: 333- 41.
|
[81] |
Herranz D, Muñoz-Martin M, Cañamero M et al. Sirt1 improves healthy ageing and protects from metabolic syndrome-associated cancer. Nat Commun 2010; 1: 3.
|
[82] |
Satoh A, Brace CS, Rensing N et al. Sirt1 extends life span and delays aging in mice through the regulation of Nk2 homeobox 1 in the DMH and LH. Cell Metab 2013; 18: 416- 30.
|
[83] |
Chen D, Steele AD, Lindquist S et al. Increase in activity during calorie restriction requires Sirt1. Science 2005; 310: 1641.
|
[84] |
Satoh A, Brace CS, Ben-Josef G et al. SIRT1 promotes the central adaptive response to diet restriction through activation of the dorsomedial and lateral nuclei of the hypothalamus. J Neurosci 2010; 30: 10220- 32.
|
[85] |
Boily G, Seifert EL, Bevilacqua L et al. SirT1 regulates energy metabolism and response to caloric restriction in mice. PLoS One 2008; 3: e1759.
|
[86] |
Caron AZ, He X, Mottawea W et al. The SIRT1 deacetylase protects mice against the symptoms of metabolic syndrome. FASEB J 2014; 28: 1306- 16.
|
[87] |
Assali DR, Hsu CT, Gunapala KM et al. Food anticipatory activity on a calorie-restricted diet is independent of Sirt1. PLoS One 2018; 13: e0199586.
|
[88] |
Kerr NL. HARKing: hypothesizing after the results are known. Pers Soc Psychol Rev 1998; 2: 196- 217.
|
[89] |
Flachsbart F, Croucher PJ, Nikolaus S et al. Sirtuin 1 (SIRT1) sequence variation is not associated with exceptional human longevity. Exp Gerontol 2006; 41: 98- 102.
|
[90] |
Kuningas M, Putters M, Westendorp RG et al. SIRT1 gene, age-related diseases, and mortality: the Leiden 85-plus study. J Gerontol A Biol Sci Med Sci 2007; 62: 960- 5.
|
[91] |
DeVito NJ, Goldacre B. Catalogue of bias: publication bias. BMJ Evid Based Med 2019; 24: 53- 4.
|
[92] |
Entman RM. Framing bias: media in the distribution of power. J Commun 2007; 57: 163- 73.
|
[93] |
Del Vicario M, Scala A, Caldarelli G et al. Modeling confirmation bias and polarization. Sci Rep 2017; 7: 40391.
|
[94] |
Cimen H, Han MJ, Yang Y et al. Regulation of succinate dehydrogenase activity by SIRT3 in mammalian mitochondria. Biochemistry 2010; 49: 304- 11.
|
[95] |
Hirschey MD, Shimazu T, Goetzman E et al. SIRT3 regulates mitochondrial fatty-acid oxidation by reversible enzyme deacetylation. Nature 2010; 464: 121- 5.
|
[96] |
Qiu X, Brown K, Hirschey MD et al. Calorie restriction reduces oxidative stress by SIRT3-mediated SOD2 activation. Cell Metab 2010; 12: 662- 7.
|
[97] |
Ghanta S, Grossmann RE, Brenner C. Mitochondrial protein acetylation as a cell-intrinsic, evolutionary driver of fat storage: chemical and metabolic logic of acetyl-lysine modifications. Crit Rev Biochem Mol Biol 2013; 48: 561- 74.
|
[98] |
Wagner GR, Hirschey MD. Nonenzymatic protein acylation as a carbon stress regulated by sirtuin deacylases.Mol Cell 2014; 54: 5- 16.
|
[99] |
Pillai VB, Bindu S, Sharp W et al. Sirt3 protects mitochondrial DNA damage and blocks the development of doxorubicin-induced cardiomyopathy in mice. Am J Physiol Heart Circ Physiol 2016; 310: H962- 972.
|
[100] |
Kincaid B, Bossy-Wetzel E. Forever young: SIRT3 a shield against mitochondrial meltdown, aging, and neurodegeneration. Front Aging Neurosci 2013; 5: 48.
|
[101] |
Mostoslavsky R, Chua KF, Lombard DB et al. Genomic instability and aging-like phenotype in the absence of mammalian SIRT6. Cell 2006; 124: 315- 29.
|
[102] |
Kanfi Y, Naiman S, Amir G et al. The sirtuin SIRT6 regulates lifespan in male mice. Nature 2012; 483: 218- 21.
|
[103] |
Roichman A, Elhanati S, Aon MA et al. Restoration of energy homeostasis by SIRT6 extends healthy lifespan. Nat Commun 2021; 12: 3208.
|
[104] |
Palliyaguru DL, Shiroma EJ, Nam JK et al. Fasting blood glucose as a predictor of mortality: lost in translation. Cell Metab 2021; 33: 2189- 200.e3.
|
[105] |
Kulkarni AS, Gubbi S, Barzilai N. Benefits of metformin in attenuating the hallmarks of aging. Cell Metab 2020; 32: 15- 30.
|
[106] |
Madiraju AK, Erion DM, RahimiY
|
[107] |
Duquesnoy RJ, Christensen K, Pedersen GM et al. Development of immunodeficiency of pituitary dwarf mice. Amer Zool 1975; 15: 167- 74.
|
[108] |
Bieganowski P, Brenner C. Discoveries of nicotinamide riboside as a nutrient and conserved NRK genes establish a preiss-handler independent route to NAD+ in fungi and humans. Cell 2004; 117: 495- 502.
|
[109] |
Belenky P, Racette FG, Bogan KL et al. Nicotinamide riboside promotes Sir2 silencing and extends lifespan via Nrk and Urh1/ Pnp1/Meu1 pathways to NAD+. Cell 2007; 129: 473- 84.
|
[110] |
Cantó C, Houtkooper RH, Pirinen E et al. The NAD(+) precursor nicotinamide riboside enhances oxidative metabolism and protects against high-fat diet-induced obesity. Cell Metab 2012; 15: 838- 47.
|
[111] |
Mills KF, Yoshida S, Stein LR et al. Long-term administration of nicotinamide mononucleotide mitigates age-associated physiological decline in mice. Cell Metab 2016; 24: 795- 806.
|
[112] |
Belenky P, Bogan KL, Brenner C. NAD+ metabolism in health and disease. Trends Biochem Sci 2007; 32: 12- 9.
|
[113] |
Trammell SA, Brenner C. Targeted, LCMS-based metabolomics for quantitative measurement of NAD(+) metabolites. Comput Struct Biotechnol J 2013; 4: e201301012.
|
[114] |
Trammell SA, Weidemann BJ, Chadda A et al. Nicotinamide riboside opposes type 2 diabetes and neuropathy in mice. Sci Rep 2016; 6: 26933.
|
[115] |
Di Stefano M, Nascimento-Ferreira I, Orsomando G et al. A rise in NAD precursor nicotinamide mononucleotide (NMN) after injury promotes axon degeneration. Cell Death Differ 2015; 22: 731- 42.
|
[116] |
Vaur P, Brugg B, Mericskay M et al. Nicotinamide riboside, a form of vitamin B3, protects against excitotoxicity-induced axonal degeneration. FASEB J 2017; 31: 5440- 52.
|
[117] |
Brown KD, Maqsood S, Huang JY et al. Activation of SIRT3 by the NAD+ precursor nicotinamide riboside protects from noise-induced hearing loss. Cell Metab 2014; 20: 1059- 68.
|
[118] |
Murata MM, Kong X, Moncada E et al. NAD+ consumption by PARP1 in response to DNA damage triggers metabolic shift critical for damaged cell survival. Mol Biol Cell 2019; 30: 2584- 97.
|
[119] |
Diguet N, Trammell SAJ, Tannous C et al. Nicotinamide riboside preserves cardiac function in a mouse model of dilated cardiomyopathy. Circulation 2018; 137: 2256- 73.
|
[120] |
Ear PH, Chadda A, Gumusoglu SB et al. Maternal nicotinamide riboside enhances postpartum weight loss, juvenile offspring development, and neurogenesis of adult offspring. Cell Rep 2019; 26: 969- 83.e4.
|
[121] |
Fons NR, Sundaram RK, Breuer GA et al. PPM1D mutations silence NAPRT gene expression and confer NAMPT inhibitor sensitivity in glioma. Nat Commun 2019; 10: 3790.
|
[122] |
Parker R, Schmidt MS, Cain O et al. The NAD metabolome is functionally depressed in patients undergoing liver transplantation for alcohol-related liver disease. Hepatol Commun 2020; 4: 1183- 92.
|
[123] |
Nam TS, Park DR, Rah SY et al. Interleukin-8 drives CD38 to form NAADP from NADP(+) and NAAD in the endolysosomes to mobilize Ca(2+) and effect cell migration. FASEB J 2020; 34: 12565- 76.
|
[124] |
Heer CD, Sanderson DJ, Voth LS et al. Coronavirus infection and PARP expression dysregulate the NAD metabolome: an actionable component of innate immunity. J Biol Chem 2020; 295: 17986- 96.
|
[125] |
Pirinen E, Auranen M, Khan NA et al. Niacin cures systemic NAD(+) deficiency and improves muscle performance in adult-onset mitochondrial myopathy. Cell Metab 2020; 31: 1078- 90.e5.
|
[126] |
Covarrubias AJ, Kale A, Perrone R et al. Senescent cells promote tissue NAD(+) decline during ageing via the activation of CD38(+) macrophages. Nat Metab 2020; 2: 1265- 83.
|
[127] |
Zhao ZY, Xie XJ, Li WH et al. A cell-permeant mimetic of NMN activates SARM1 to produce cyclic ADP-ribose and induce non-apoptotic cell death. iScience 2019; 15: 452- 66.
|
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