Nicotinamide mononucleotide (NMN) deamidation and indirect regulation of the NAD metabolome

2020 ◽  
Author(s):  
Lynn-Jee Kim ◽  
Timothy Chalmers ◽  
Greg Smith ◽  
Catherine Li ◽  
Abhirup Das ◽  
...  

Abstract Treatment with nicotinamide mononucleotide (NMN) is a prominent strategy to address the age-related decline in nicotinamide adenine dinucleotide (NAD+) levels for maintaining aspects of late-life health. It is assumed that exogenous NMN is directly incorporated into the NAD+ metabolome in mammals via the canonical recycling pathway. Here, we show that NMN can undergo direct deamidation and incorporation via the de novo pathway, which is in part mediated by the gut microbiome. Surprisingly, isotope labelling studies revealed that exogenous NMN treatment potently increased the endogenous production of unlabelled NAD metabolites, suggesting that exogenous NMN impacts the NAD metabolome through indirect means, rather than through its direct incorporation. This included a striking increase in endogenous production of the metabolites nicotinic acid riboside (NaR) and nicotinamide riboside (NR) which was amplified in antibiotics treated animals, suggesting the production of endogenous NaR/NR through altered metabolic flux, enzyme kinetics and/or an as-yet unidentified pathway that interacts with the gut microbiome.

2020 ◽  
Author(s):  
Lynn-Jee Kim ◽  
Timothy J. Chalmers ◽  
Greg C. Smith ◽  
Abhirup Das ◽  
Eric Wing Keung Poon ◽  
...  

ABSTRACTTreatment with nicotinamide mononucleotide (NMN) is a prominent strategy to address the age-related decline in nicotinamide adenine dinucleotide (NAD+) levels for maintaining aspects of late-life health. It is assumed that exogenous NMN is directly incorporated into NAD+ in mammals by the canonical recycling pathway, however the need for NAD+ is conserved across evolution, including bacteria in the gut microbiome, which can deamidate NMN to nicotinic acid mononucleotide (NaMN). Here, we use strategic isotope labelling studies to demonstrate a role for the gut microbiome in deamidating orally delivered NMN into NaMN prior to its uptake and incorporation in mammals. Microbiome depletion increased the overall abundance of NAD metabolites, suggesting a competition relationship. Strikingly, treatment with labelled NMN increased the production of unlabelled NAD precursors, with a greater than 3-fold increase in endogenous NR levels in the gut of antibiotics treated animals upon labelled NMN treatment. These data suggest that exogenous NMN impacts the NAD metabolome through indirect means, rather than through its direct incorporation, including through the production of endogenous NR via an as-yet unidentified pathway, and demonstrate an important role for the gut microbiome in the assimilation of orally delivered NMN.


2001 ◽  
Vol 183 (13) ◽  
pp. 3974-3981 ◽  
Author(s):  
Gabriele Kemmer ◽  
Thomas J. Reilly ◽  
Joachim Schmidt-Brauns ◽  
Gary W. Zlotnik ◽  
Bruce A. Green ◽  
...  

ABSTRACT Haemophilus influenzae has an absolute requirement for NAD (factor V) because it lacks almost all the biosynthetic enzymes necessary for the de novo synthesis of that cofactor. Factor V can be provided as either nicotinamide adenosine dinucleotide (NAD), nicotinamide mononucleotide (NMN), or nicotinamide riboside (NR) in vitro, but little is known about the source or the mechanism of uptake of these substrates in vivo. As shown by us earlier, at least two gene products are involved in the uptake of NAD, the outer membrane lipoprotein e (P4), which has phosphatase activity and is encoded by hel, and a periplasmic NAD nucleotidase, encoded by nadN. It has also been observed that the latter gene product is essential for H. influenzae growth on media supplemented with NAD. In this report, we describe the functions and substrates of these two proteins as they act together in an NAD utilization pathway. Data are provided which indicate that NadN harbors not only NAD pyrophosphatase but also NMN 5′-nucleotidase activity. Thee (P4) protein is also shown to have NMN 5′-nucleotidase activity, recognizing NMN as a substrate and releasing NR as its product. Insertion mutants of nadN or deletion and site-directed mutants of hel had attenuated growth and a reduced uptake phenotype when NMN served as substrate. Ahel and nadN double mutant was only able to grow in the presence of NR, whereas no uptake of NMN was observed.


2021 ◽  
Vol 22 (7) ◽  
pp. 3709
Author(s):  
Fiqri D. Khaidizar ◽  
Yasumasa Bessho ◽  
Yasukazu Nakahata

Aging is a phenomenon underlined by complex molecular and biochemical changes that occur over time. One of the metabolites that is gaining strong research interest is nicotinamide adenine dinucleotide, NAD+, whose cellular level has been shown to decrease with age in various tissues of model animals and humans. Administration of NAD+ precursors, nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR), to supplement NAD+ production through the NAD+ salvage pathway has been demonstrated to slow down aging processes in mice. Therefore, NAD+ is a critical metabolite now understood to mitigate age-related tissue function decline and prevent age-related diseases in aging animals. In human clinical trials, administration of NAD+ precursors to the elderly is being used to address systemic age-associated physiological decline. Among NAD+ biosynthesis pathways in mammals, the NAD+ salvage pathway is the dominant pathway in most of tissues, and NAMPT is the rate limiting enzyme of this pathway. However, only a few activators of NAMPT, which are supposed to increase NAD+, have been developed so far. In this review, we will focus on the importance of NAD+ and the possible application of an activator of NAMPT to promote successive aging.


Glycobiology ◽  
2020 ◽  
Vol 30 (11) ◽  
pp. 859-871
Author(s):  
Maurice Wong ◽  
Gege Xu ◽  
Mariana Barboza ◽  
Izumi Maezawa ◽  
Lee-Way Jin ◽  
...  

Abstract Saccharides in our diet are major sources of carbon for the formation of biomass such as proteins, lipids, nucleic acids and glycans. Among the dietary monosaccharides, glucose occupies a central role in metabolism, but human blood contains regulated levels of other monosaccharides as well. Their influence on metabolism and how they are utilized have not been explored thoroughly. Applying metabolic flux analysis on glycan synthesis can reveal the pathways that supply glycosylation precursors and provide a snapshot of the metabolic state of the cell. In this study, we traced the incorporation of six 13C uniformly labeled monosaccharides in the N-glycans, O-glycans and glycosphingolipids of both pluripotent and neural NTERA-2 cells. We gathered detailed isotopologue data for hundreds of glycoconjugates using mass spectrometry methods. The contributions of de novo synthesis and direct incorporation pathways for glucose, mannose, fructose, galactose, N-acetylglucosamine and fucose were determined based on their isotope incorporation. Co-feeding studies revealed that fructose incorporation is drastically decreased by the presence of glucose, while mannose and galactose were much less affected. Furthermore, increased sialylation slowed down the turnover of glycans, but fucosylation attenuated this effect. Our results demonstrated that exogenous monosaccharide utilization can vary markedly depending on the cell differentiation state and monosaccharide availability, and that the incorporation of carbons can also differ among different glycan structures. We contend that the analysis of metabolic isotope labeling of glycans can yield new insights about cell metabolism.


2019 ◽  
Vol 3 (1) ◽  
pp. 105-130 ◽  
Author(s):  
Tyler G. Demarest ◽  
Mansi Babbar ◽  
Mustafa N. Okur ◽  
Xiuli Dan ◽  
Deborah L. Croteau ◽  
...  

Aging is a major risk factor for many types of cancer, and the molecular mechanisms implicated in aging, progeria syndromes, and cancer pathogenesis display considerable similarities. Maintaining redox homeostasis, efficient signal transduction, and mitochondrial metabolism is essential for genome integrity and for preventing progression to cellular senescence or tumorigenesis. NAD+is a central signaling molecule involved in these and other cellular processes implicated in age-related diseases and cancer. Growing evidence implicates NAD+decline as a major feature of accelerated aging progeria syndromes and normal aging. Administration of NAD+precursors such as nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN) offer promising therapeutic strategies to improve health, progeria comorbidities, and cancer therapies. This review summarizes insights from the study of aging and progeria syndromes and discusses the implications and therapeutic potential of the underlying molecular mechanisms involved in aging and how they may contribute to tumorigenesis.


Gerontology ◽  
2018 ◽  
Vol 64 (6) ◽  
pp. 513-520 ◽  
Author(s):  
Sangkyu Kim ◽  
S. Michal Jazwinski

The gut microbiota shows a wide inter-individual variation, but its within-individual variation is relatively stable over time. A functional core microbiome, provided by abundant bacterial taxa, seems to be common to various human hosts regardless of their gender, geographic location, and age. With advancing chronological age, the gut microbiota becomes more diverse and variable. However, when measures of biological age are used with adjustment for chronological age, overall richness decreases, while a certain group of bacteria associated with frailty increases. This highlights the importance of considering biological or functional measures of aging. Studies using model organisms indicate that age-related gut dysbiosis may contribute to unhealthy aging and reduced longevity. The gut microbiome depends on the host nutrient signaling pathways for its beneficial effects on host health and lifespan, and gut dysbiosis disrupting the interdependence may diminish the beneficial effects or even have reverse effects. Gut dysbiosis can trigger the innate immune response and chronic low-grade inflammation, leading to many age-related degenerative pathologies and unhealthy aging. The gut microbiota communicates with the host through various biomolecules, nutrient signaling-independent pathways, and epigenetic mechanisms. Disturbance of these communications by age-related gut dysbiosis can affect the host health and lifespan. This may explain the impact of the gut microbiome on health and aging.


2018 ◽  
Vol 18 (5-6) ◽  
pp. 233-238
Author(s):  
Frederic Sampedro ◽  
Juan Marín-Lahoz ◽  
Saul Martínez-Horta ◽  
Javier Pagonabarraga ◽  
Jaime Kulisevsky

The role of cerebrospinal fluid (CSF) biomarkers such as CSF α-synuclein and CSF tau in predicting cognitive decline in Parkinson’s disease (PD) continues to be inconsistent. Here, using a cohort of de novo PD patients with preserved cognition from the Parkinson’s Progression Markers Initiative (PPMI), we show that the SNCA rs356181 single nucleotide polymorphism (SNP) modulates the effect of these CSF biomarkers on cortical thinning. Depending on this SNP’s genotype, cortical atrophy was associated with either higher or lower CSF biomarker levels. Additionally, this SNP modified age-related atrophy. Importantly, the integrity of the brain regions where this phenomenon was observed correlated with cognitive measures. These results suggest that this genetic variation of the gene encoding the α-synuclein protein, known to be involved in the development of PD, also interferes in its subsequent neurodegeneration. Overall, our findings could shed light on the so far incongruent association of common CSF biomarkers with cognitive decline in PD.


2019 ◽  
Vol 597 (9) ◽  
pp. 2361-2378 ◽  
Author(s):  
Vienna E. Brunt ◽  
Rachel A. Gioscia‐Ryan ◽  
James J. Richey ◽  
Melanie C. Zigler ◽  
Lauren M. Cuevas ◽  
...  

Author(s):  
Sana Amanat ◽  
Teresa Requena ◽  
Jose Antonio Lopez-Escamez

Exome sequencing has been commonly used in rare diseases by selecting multiplex families or singletons with an extreme phenotype (EP) to search for rare variants in coding regions. The EP strategy covers both extreme ends of a disease spectrum and it has been also used to investigate the contribution of rare variants to heritability in complex clinical traits. We have conducted a systematic review to find evidence supporting the use of EP strategies to search for rare variants in genetic studies of complex diseases, to highlight the contribution of rare variation to the genetic structure of multiallelic conditions. After performing the quality assessment of the retrieved records, we selected 19 genetic studies considering EP to demonstrate genetic association. All the studies successfully identified several rare variants, de novo mutations and many novel candidate genes were also identified by selecting an EP. There is enough evidence to support that the EP approach in patients with an early onset of the disease can contribute to the identification of rare variants in candidate genes or pathways involved in complex diseases. EP patients may contribute to a better understanding of the underlying genetic architecture of common heterogeneous disorders such as tinnitus or age-related hearing loss.


2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Nicoletta Marchesi ◽  
Natthakan Thongon ◽  
Alessia Pascale ◽  
Alessandro Provenzani ◽  
Ali Koskela ◽  
...  

RNA-binding protein dysregulation and altered expression of proteins involved in the autophagy/proteasome pathway play a role in many neurodegenerative disease onset/progression, including age-related macular degeneration (AMD). HuR/ELAVL1 is a master regulator of gene expression in human physiopathology. In ARPE-19 cells exposed to the proteasomal inhibitor MG132, HuR positively affects at posttranscriptional level p62 expression, a stress response gene involved in protein aggregate clearance with a role in AMD. Here, we studied the early effects of the proautophagy AICAR + MG132 cotreatment on the HuR-p62 pathway. We treated ARPE-19 cells with Erk1/2, AMPK, p38MAPK, PKC, and JNK kinase inhibitors in the presence of AICAR + MG132 and evaluated HuR localization/phosphorylation and p62 expression. Two-hour AICAR + MG132 induces both HuR cytoplasmic translocation and threonine phosphorylation via the Erk1/2 pathway. In these conditions, p62 mRNA is loaded on polysomes and its translation in de novo protein is favored. Additionally, for the first time, we report that JNK can phosphorylate HuR, however, without modulating its localization. Our study supports HuR’s role as an upstream regulator of p62 expression in ARPE-19 cells, helps to understand better the early events in response to a proautophagy stimulus, and suggests that modulation of the autophagy-regulating kinases as potential therapeutic targets for AMD may be relevant.


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