Project description:The prevention or delay of the onset of age-related diseases prolongs survival and improves quality of life while reducing the burden on the health care system. Activation of sirtuin 6 (SIRT6), an NAD+-dependent deacetylase, improves metabolism and confers protection against physiological and cognitive disturbances in old age. Here we show that MDL-800 is a specific SIRT6 activator that has health and lifespan benefits in adult mice fed a standard diet. We found extension in lifespan, delayed onset of age-related metabolic diseases, and improved general health in mice fed a standard diet after MDL-800 supplementation. Treatment with MDL-800 induced synthesis of anti-oxidation related proteins, and this rejuvenated HSCs and ISCs in aged mice. Inhibition of pro-inflammatory gene expression in both liver and muscle of MDL-800-treated animals was noted. MDL-800 lowered the level of NF-kB pathway and improved fatty acid metabolism in liver. Combined with our previous work, the current study further supports the beneficial effects of MDL-800 on health across the lifespan in mice.
Project description:Aging leads to a gradual decline in physical activity and disrupted energy homeostasis. The NAD+-dependent SIRT6 deacylase regulates aging and metabolism through mechanisms that largely remain unknown. Here, we show that SIRT6 overexpression leads to a reduction in frailty and lifespan extension in both male and female B6 mice. A combination of physiological assays, in vivo multi-omics analyses and 13C lactate tracing identified an age-dependent decline in glucose homeostasis and hepatic gluconeogenesis (GNG) capacity in wild type mice. In contrast, aged SIRT6-transgenic mice preserve GNG capacity and glucose homeostasis through an improvement in the utilization of two major GNG precursors, lactate and glycerol. To mediate these changes, mechanistically, SIRT6 increases hepatic GNG gene expression, de novo NAD+ synthesis, and systemically enhances glycerol release from adipose tissue. These findings show that SIRT6 optimizes energy homeostasis in old age to delay frailty and preserve healthy aging.
Project description:The significant increase in the human life-span during the last century confronts us with great medical challenges. To answer them, one must understand and control the mechanisms that determine healthy ageing. The highly conserved sirtuin deacetylases were shown to regulate life-span in lower organisms. Yet, the role of mammalian sirtuins, SIRT1 to 7, in regulating life-span is currently unclear. Here, we show that in SIRT6 transgenic mice (Sirt6-tg), the males but not the females, have a significant increase in life-span. Gene expression analysis revealed significant differences for male Sirt6-tg in comparison to male wild-type mice. Transgenic males display lower serum IGF-1 levels, increased levels of IGFBP-1 and altered phosphorylation levels of major components of the IGF-1 pathway, a key factor in the regulation of life-span. This study is the first to show regulation of mammalian life-span by a sirtuin family member, and has important therapeutic implications for age-related diseases.
Project description:Rapamycin extends life span in mice, but it remains unclear if this compound also delays mammalian aging. Here, we present results from a comprehensive large-scale assessment of a wide rage of structural and functional aging phenotypes in mice. Rapamycin extended life span but showed few effects on a large number of systemic aging phenotypes, suggesting that rapamycin's effects on aging are largely limited to the regulation of age-related mortality and carcinogenesis.
Project description:Rapamycin extends life span in mice, but it remains unclear if this compound also delays mammalian aging. Here, we present results from a comprehensive large-scale assessment of a wide rage of structural and functional aging phenotypes in mice. Rapamycin extended life span but showed few effects on a large number of systemic aging phenotypes, suggesting that rapamycin's effects on aging are largely limited to the regulation of age-related mortality and carcinogenesis. Total RNA obtained from 2-4 male mice of each analysed group (25 weeks old controls, 25 month old controls, 25 month old rapamycin treated)
Project description:Whole body SIRT6 overexpression (SIRT6-tg) extends lifespan. Here we examine the effect of SIRT6 overexpression on liver mRNA profile
Project description:Aging leads to a gradual decline in physical activity and disrupted energy homeostasis. The NAD+-dependent SIRT6 deacylase regulates aging and metabolism through mechanisms that largely remain unknown. Here, we show that SIRT6 overexpression leads to a reduction in frailty and lifespan extension in both male and female B6 mice. A combination of physiological assays, in vivo multi-omics analyses and 13C lactate tracing identified an age-dependent decline in glucose homeostasis and hepatic glucose output in wild type mice. In contrast, aged SIRT6-transgenic mice preserve hepatic glucose output and glucose homeostasis through an improvement in the utilization of two major gluconeogenic precursors, lactate and glycerol. To mediate these changes, mechanistically, SIRT6 increases hepatic gluconeogenic gene expression, de novo NAD+ synthesis, and systemically enhances glycerol release from adipose tissue. These findings show that SIRT6 optimizes energy homeostasis in old age to delay frailty and preserve healthy aging.
Project description:Protein deacetylase SIRT6 and protein kinase ATM both decline during aging, which are of importance in regualtion of glucose metabolism . To explore the mechnisms of SIRT6 and ATM in glycolysis, we analysed the gene expressions in murine embryonic fibroblast cells generated from wildtype, Sirt6-/-, or Atm-/- mice.
Project description: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 Sirt6 in mice results in accelerated aging and premature death within a month. Here, we show that haploinsufficiency (i.e., heterozygous deletion) of Trp53 dramatically extends the lifespan of both female and male Sirt6-deficient mice. Haploinsufficiency of Trp53 in Sirt6-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.