A decline in capillary density and blood flow with age is a major cause of mortality and morbidity. Understanding why this occurs is key to future gains in human health. NAD precursors reverse ...aspects of aging, in part, by activating sirtuin deacylases (SIRT1–SIRT7) that mediate the benefits of exercise and dietary restriction (DR). We show that SIRT1 in endothelial cells is a key mediator of pro-angiogenic signals secreted from myocytes. Treatment of mice with the NAD+ booster nicotinamide mononucleotide (NMN) improves blood flow and increases endurance in elderly mice by promoting SIRT1-dependent increases in capillary density, an effect augmented by exercise or increasing the levels of hydrogen sulfide (H2S), a DR mimetic and regulator of endothelial NAD+ levels. These findings have implications for improving blood flow to organs and tissues, increasing human performance, and reestablishing a virtuous cycle of mobility in the elderly.
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•Reduced blood flow with age is due to loss of endothelial NAD+-SIRT1 activity•NAD+ and H2S control muscle angiogenesis and increase endurance in old mice•The NAD precursor NMN mimics and augments exercise by inhibiting NICD-Notch•Neovascularization is as important as mitochondria for rejuvenating muscle
Endothelial SIRT1 regulates pro-angiogenic signals secreted from myocytes and improves muscle health. Treatment of mice with NAD precursor nicotinamide mononucleotide improves vascular and increases endurance in aging mice.
The NAD+‐dependent deacylase family of sirtuin enzymes have been implicated in biological ageing, late‐life health and overall lifespan, though of these members, a role for sirtuin‐2 (SIRT2) is less ...clear. Transgenic overexpression of SIRT2 in the BubR1 hypomorph model of progeria can rescue many aspects of health and increase overall lifespan, due to a specific interaction between SIRT2 and BubR1 that improves the stability of this protein. It is less clear whether SIRT2 is relevant to biological ageing outside of a model where BubR1 is under‐expressed. Here, we sought to test whether SIRT2 over‐expression would impact the overall health and lifespan of mice on a nonprogeroid, wild‐type background. While we previously found that SIRT2 transgenic overexpression prolonged female fertility, here, we did not observe any additional impact on health or lifespan, which was measured in both male and female mice on standard chow diets, and in males challenged with a high‐fat diet. At the biochemical level, NMR studies revealed an increase in total levels of a number of metabolites in the brain of SIRT2‐Tg animals, pointing to a potential impact in cell composition; however, this did not translate into functional differences. Overall, we conclude that strategies to enhance SIRT2 protein levels may not lead to increased longevity.
Sirtuin 2 (SIRT2) has been implicated in cell cycle regulation, genome stability and neurodegeneration, and its over‐expression in BubR1 hypomorph progeroid mice extends lifespan. Here, comprehensive phenotyping in male and female, chow and high fat fed mice shows no impact of SIRT2 over‐expression on healthspan or lifespan on a non‐progeroid, wild‐type background.
The nicotinamide adenine dinucleotide (NAD+) precursor nicotinamide mononucleotide (NMN) is a proposed therapy for age‐related disease, whereby it is assumed that NMN is incorporated into NAD+ ...through the canonical recycling pathway. During oral delivery, NMN is exposed to the gut microbiome, which could modify the NAD+ metabolome through enzyme activities not present in the mammalian host. We show that orally delivered NMN can undergo deamidation and incorporation in mammalian tissue via the de novo pathway, which is reduced in animals treated with antibiotics to ablate the gut microbiome. Antibiotics increased the availability of NAD+ metabolites, suggesting the microbiome could be in competition with the host for dietary NAD+ precursors. These findings highlight new interactions between NMN and the gut microbiome.
Exogenous treatment with the nicotinamide adenine dinucleotide (NAD+) precursor nicotinamide mononucleotide (NMN) is presumed to elevate NAD+ levels through its direct incorporation via the canonical NAD+ recycling pathway. Here, metabolic tracing of strategically designed NMN isotopologues in vivo reveals that the gut microbiome mediates NMN deamidation and uptake into the NAD+ metabolome via the de novo pathway.
Reproductive aging in female mammals is an irreversible process associated with declining oocyte quality, which is the rate-limiting factor to fertility. Here, we show that this loss of oocyte ...quality with age accompanies declining levels of the prominent metabolic cofactor nicotinamide adenine dinucleotide (NAD+). Treatment with the NAD+ metabolic precursor nicotinamide mononucleotide (NMN) rejuvenates oocyte quality in aged animals, leading to restoration in fertility, and this can be recapitulated by transgenic overexpression of the NAD+-dependent deacylase SIRT2, though deletion of this enzyme does not impair oocyte quality. These benefits of NMN extend to the developing embryo, where supplementation reverses the adverse effect of maternal age on developmental milestones. These findings suggest that late-life restoration of NAD+ levels represents an opportunity to rescue female reproductive function in mammals.
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•Declining NAD(P)H is associated with oocyte dysfunction during reproductive aging•Oocyte quality and fertility can be restored by NMN treatment in aged mice•Supplementation of embryo media with NMN improves developmental milestones•SIRT2 overexpression mimics benefits of NMN but is unlikely to mediate its effects
Declining oocyte quality is considered an irreversible feature of aging and is rate limiting for human fertility. Bertoldo et al. show that reversing an age-dependent decline in NAD(P)H restores oocyte quality, embryo development, and functional fertility in aged mice. These findings may be relevant to reproductive medicine.
NMN dampened exercise-induced benefits on glucose handling in diet-induced obesity. NMN administration alongside treadmill exercise enhanced the ratio of antioxidants to prooxidants. We suggest that ...NMN administration may not be beneficial when NAD
+
levels are replete.
Almost 40% of adults worldwide are classified as overweight or obese. Exercise is a beneficial intervention in obesity, partly due to increases in mitochondrial activity and subsequent increases in nicotinamide adenine dinucleotide (NAD
+
), an important metabolic cofactor. Recent studies have shown that increasing NAD
+
levels through pharmacological supplementation with precursors such as nicotinamide mononucleotide (NMN) improved metabolic health in high-fat-diet (HFD)-fed mice. However, the effects of combined exercise and NMN supplementation are unknown. Thus, here we examined the combined effects of NMN and treadmill exercise in female mice with established obesity after 10 wk of diet. Five-week-old female C57BL/6J mice were exposed to a control diet ( n = 16) or HFD. Mice fed a HFD were either untreated (HFD; n = 16), received NMN in drinking water (400 mg/kg; HNMN; n = 16), were exposed to treadmill exercise 6 days/wk (HEx; n = 16), or were exposed to exercise combined with NMN (HNEx; n = 16). Although some metabolic benefits of NMN have been described, at this dose, NMN administration impaired several aspects of exercise-induced benefits in obese mice, including glucose tolerance, glucose-stimulated insulin secretion from islets, and hepatic triglyceride accumulation. HNEx mice also exhibited increased antioxidant and reduced prooxidant gene expression in both islets and muscle, suggesting that altered redox status is associated with the loss of exercise-induced health benefits with NMN cotreatment. Our data show that NMN treatment impedes the beneficial metabolic effects of exercise in a mouse model of diet-induced obesity in association with disturbances in redox metabolism.
NEW & NOTEWORTHY NMN dampened exercise-induced benefits on glucose handling in diet-induced obesity. NMN administration alongside treadmill exercise enhanced the ratio of antioxidants to prooxidants. We suggest that NMN administration may not be beneficial when NAD
+
levels are replete.
Background and Aims: Chemotherapy induced ovarian failure and infertility is an important concern in female cancer patients of reproductive age or younger, and non-invasive, pharmacological ...approaches to prevent chemotherapy induced infertility are urgently needed. Here we investigate whether pharmacological elevation of nicotinamide adenine dinucleotide (NAD+) ameliorates chemotherapy induced female infertility in mice. Method: 8-week-old C57BL6 female mice were treated +/- chemotherapy (doxorubicin, Dox; 10 mg/kg) and +/- nicotinamide mononucleotide (NMN; 200 mg/kg i.p. once and 2 g/L in drinking water on-going), an orally bioavailable metabolic precursor to NAD+. Effects on fertility were measured by impact on ovarian reserve and folliculogenesis, ovulation rates and breeding performance. Effects on the ovarian NAD+ metabolome were assessed by mass spectrometry. A potential adverse effect of NMN on the efficiency of chemotherapy was assessed using a xenograft model of mammary cancer. Results: NMN treatment did not prevent a decline in the ovarian reserve caused by chemotherapy but did maintain the health of the remaining primordial follicle and total follicle populations, leading to a restoration in oocyte yield in chemo-treated mice (Dox vs Dox+NMN; P<0.007), culminating in an increase in pups born/mating in chemo+NMN treated mice (P<0.05). Chemo caused ovarian NMN, NADP+ and NADPH depletion, and NADPH was restored by NMN, which likely contributes to Dox detoxification. Importantly, treatment of the breast cancer mouse model with NMN reduced tumour growth and did not impair the efficacy of chemotherapy drugs in vivo or in diverse cancer cell lines. Conclusion: Overall, these findings raise the possibility that NAD+ precursors could be a non-invasive strategy for maintaining ovarian function and fertility in cancer patients, with potential benefits in cancer therapy.
A decline in capillary density and blood flow with age is a major cause of mortality and morbidity. Understanding why this occurs is key to future gains in human health. NAD precursors reverse ...aspects of aging, in part, by activating sirtuin deacylases (SIRT1-SIRT7) that mediate the benefits of exercise and dietary restriction (DR). We show that SIRT1 in endothelial cells is a key mediator of pro-angiogenic signals secreted from myocytes. Treatment of mice with the NAD
booster nicotinamide mononucleotide (NMN) improves blood flow and increases endurance in elderly mice by promoting SIRT1-dependent increases in capillary density, an effect augmented by exercise or increasing the levels of hydrogen sulfide (H
S), a DR mimetic and regulator of endothelial NAD
levels. These findings have implications for improving blood flow to organs and tissues, increasing human performance, and reestablishing a virtuous cycle of mobility in the elderly.
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