Haploinsufficiency of <i>Trp53</i> dramatically extends the lifespan of Sirt6-deficient mice.

Abstract

Mammalian sirtuin 6 (Sirt6) is a conserved NAD⁺-dependent deacylase and mono-ADP ribosylase that is known to be involved in DNA damage repair, metabolic homeostasis, inflammation, tumorigenesis, and aging. Loss of <i>Sirt6</i> in mice results in accelerated aging and premature death within a month. Here, we show that haploinsufficiency (<i>i.e.</i>, heterozygous deletion) of <i>Trp53</i> dramatically extends the lifespan of both female and male <i>Sirt6</i>-deficient mice. Haploinsufficiency of <i>Trp53</i> in <i>Sirt6</i>-deficient mice rescues several age-related phenotypes of Sirt6-deficient mice, including reduced body size and weight, lordokyphosis, colitis, premature senescence, apoptosis, and bone marrow stem cell decline. Mechanistically, SIRT6 deacetylates p53 at lysine 381 to negatively regulate the stability and activity of p53. These findings establish that elevated p53 activity contributes significantly to accelerated aging in Sirt6-deficient mice. Our study demonstrates that p53 is a substrate of SIRT6, and highlights the importance of SIRT6-p53 axis in the regulation of aging.