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Kim GD, Qiu D, Jessen HJ, Mayer A. Metabolic Consequences of Polyphosphate Synthesis and Imminent Phosphate Limitation. mBio 2023; 14:e0010223. [PMID: 37074217 PMCID: PMC10294617 DOI: 10.1128/mbio.00102-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 03/22/2023] [Indexed: 04/20/2023] Open
Abstract
Cells stabilize intracellular inorganic phosphate (Pi) to compromise between large biosynthetic needs and detrimental bioenergetic effects of Pi. Pi homeostasis in eukaryotes uses Syg1/Pho81/Xpr1 (SPX) domains, which are receptors for inositol pyrophosphates. We explored how polymerization and storage of Pi in acidocalcisome-like vacuoles supports Saccharomyces cerevisiae metabolism and how these cells recognize Pi scarcity. Whereas Pi starvation affects numerous metabolic pathways, beginning Pi scarcity affects few metabolites. These include inositol pyrophosphates and ATP, a low-affinity substrate for inositol pyrophosphate-synthesizing kinases. Declining ATP and inositol pyrophosphates may thus be indicators of impending Pi limitation. Actual Pi starvation triggers accumulation of the purine synthesis intermediate 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), which activates Pi-dependent transcription factors. Cells lacking inorganic polyphosphate show Pi starvation features already under Pi-replete conditions, suggesting that vacuolar polyphosphate supplies Pi for metabolism even when Pi is abundant. However, polyphosphate deficiency also generates unique metabolic changes that are not observed in starving wild-type cells. Polyphosphate in acidocalcisome-like vacuoles may hence be more than a global phosphate reserve and channel Pi to preferred cellular processes. IMPORTANCE Cells must strike a delicate balance between the high demand of inorganic phosphate (Pi) for synthesizing nucleic acids and phospholipids and its detrimental bioenergetic effects by reducing the free energy of nucleotide hydrolysis. The latter may stall metabolism. Therefore, microorganisms manage the import and export of phosphate, its conversion into osmotically inactive inorganic polyphosphates, and their storage in dedicated organelles (acidocalcisomes). Here, we provide novel insights into metabolic changes that yeast cells may use to signal declining phosphate availability in the cytosol and differentiate it from actual phosphate starvation. We also analyze the role of acidocalcisome-like organelles in phosphate homeostasis. This study uncovers an unexpected role of the polyphosphate pool in these organelles under phosphate-rich conditions, indicating that its metabolic roles go beyond that of a phosphate reserve for surviving starvation.
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Affiliation(s)
- Geun-Don Kim
- Department of Immunobiology, University of Lausanne, Epalinges, Switzerland
| | - Danye Qiu
- Institute of Organic Chemistry, University of Freiburg, Freiburg, Germany
| | | | - Andreas Mayer
- Department of Immunobiology, University of Lausanne, Epalinges, Switzerland
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2
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Groth B, Lee YC, Huang CC, McDaniel M, Huang K, Lee LH, Lin SJ. The Histone Deacetylases Hst1 and Rpd3 Integrate De Novo NAD + Metabolism with Phosphate Sensing in Saccharomyces cerevisiae. Int J Mol Sci 2023; 24:ijms24098047. [PMID: 37175754 PMCID: PMC10179157 DOI: 10.3390/ijms24098047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/22/2023] [Accepted: 04/26/2023] [Indexed: 05/15/2023] Open
Abstract
Nicotinamide adenine dinucleotide (NAD+) is a critical cofactor essential for various cellular processes. Abnormalities in NAD+ metabolism have also been associated with a number of metabolic disorders. The regulation and interconnection of NAD+ metabolic pathways are not yet completely understood. By employing an NAD+ intermediate-specific genetic system established in the model organism S. cerevisiae, we show that histone deacetylases (HDACs) Hst1 and Rpd3 link the regulation of the de novo NAD+ metabolism-mediating BNA genes with certain aspects of the phosphate (Pi)-sensing PHO pathway. Our genetic and gene expression studies suggest that the Bas1-Pho2 and Pho2-Pho4 transcription activator complexes play a role in this co-regulation. Our results suggest a model in which competition for Pho2 usage between the BNA-activating Bas1-Pho2 complex and the PHO-activating Pho2-Pho4 complex helps balance de novo activity with PHO activity in response to NAD+ or phosphate depletion. Interestingly, both the Bas1-Pho2 and Pho2-Pho4 complexes appear to also regulate the expression of the salvage-mediating PNC1 gene negatively. These results suggest a mechanism for the inverse regulation between the NAD+ salvage pathways and the de novo pathway observed in our genetic models. Our findings help provide a molecular basis for the complex interplay of two different aspects of cellular metabolism.
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Affiliation(s)
- Benjamin Groth
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, CA 95616, USA
| | - Yi-Ching Lee
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, CA 95616, USA
| | - Chi-Chun Huang
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, CA 95616, USA
| | - Matilda McDaniel
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, CA 95616, USA
| | - Katie Huang
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, CA 95616, USA
| | - Lan-Hsuan Lee
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, CA 95616, USA
| | - Su-Ju Lin
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, CA 95616, USA
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3
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Emerging Role of Nicotinamide Riboside in Health and Diseases. Nutrients 2022; 14:nu14193889. [PMID: 36235542 PMCID: PMC9571518 DOI: 10.3390/nu14193889] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 09/12/2022] [Accepted: 09/14/2022] [Indexed: 11/16/2022] Open
Abstract
Among all the NAD+ precursors, nicotinamide riboside (NR) has gained the most attention as a potent NAD+-enhancement agent. This recently discovered vitamin, B3, has demonstrated excellent safety and efficacy profiles and is orally bioavailable in humans. Boosting intracellular NAD+ concentrations using NR has been shown to provide protective effects against a broad spectrum of pathological conditions, such as neurodegenerative diseases, diabetes, and hearing loss. In this review, an integrated overview of NR research will be presented. The role NR plays in the NAD+ biosynthetic pathway will be introduced, followed by a discussion on the synthesis of NR using chemical and enzymatic approaches. NR’s effects on regulating normal physiology and pathophysiology will also be presented, focusing on the studies published in the last five years.
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Groth B, Huang CC, Lin SJ. The histone deacetylases Rpd3 and Hst1 antagonistically regulate de novo NAD + metabolism in the budding yeast Saccharomyces cerevisiae. J Biol Chem 2022; 298:102410. [PMID: 36007612 PMCID: PMC9486569 DOI: 10.1016/j.jbc.2022.102410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 08/16/2022] [Accepted: 08/17/2022] [Indexed: 12/05/2022] Open
Abstract
NAD+ is a cellular redox cofactor involved in many essential processes. The regulation of NAD+ metabolism and the signaling networks reciprocally interacting with NAD+-producing metabolic pathways are not yet fully understood. The NAD+-dependent histone deacetylase (HDAC) Hst1 has been shown to inhibit de novo NAD+ synthesis by repressing biosynthesis of nicotinic acid (BNA) gene expression. Here, we alternatively identify HDAC Rpd3 as a positive regulator of de novo NAD+ metabolism in the budding yeast Saccharomyces cerevisiae. We reveal that deletion of RPD3 causes marked decreases in the production of de novo pathway metabolites, in direct contrast to deletion of HST1. We determined the BNA expression profiles of rpd3Δ and hst1Δ cells to be similarly opposed, suggesting the two HDACs may regulate the BNA genes in an antagonistic fashion. Our chromatin immunoprecipitation analysis revealed that Rpd3 and Hst1 mutually influence each other’s binding distribution at the BNA2 promoter. We demonstrate Hst1 to be the main deacetylase active at the BNA2 promoter, with hst1Δ cells displaying increased acetylation of the N-terminal tail lysine residues of histone H4, H4K5, and H4K12. Conversely, we show that deletion of RPD3 reduces the acetylation of these residues in an Hst1-dependent manner. This suggests that Rpd3 may function to oppose spreading of Hst1-dependent heterochromatin and represents a unique form of antagonism between HDACs in regulating gene expression. Moreover, we found that Rpd3 and Hst1 also coregulate additional targets involved in other branches of NAD+ metabolism. These findings help elucidate the complex interconnections involved in effecting the regulation of NAD+ metabolism.
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Affiliation(s)
- Benjamin Groth
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, California, USA
| | - Chi-Chun Huang
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, California, USA
| | - Su-Ju Lin
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, California, USA.
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5
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Nicotinamide Riboside and Dihydronicotinic Acid Riboside Synergistically Increase Intracellular NAD+ by Generating Dihydronicotinamide Riboside. Nutrients 2022; 14:nu14132752. [PMID: 35807932 PMCID: PMC9269339 DOI: 10.3390/nu14132752] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 06/29/2022] [Accepted: 06/29/2022] [Indexed: 12/20/2022] Open
Abstract
Through evolution, eukaryote organisms have developed the ability to use different molecules as independent precursors to generate nicotinamide adenine dinucleotide (NAD+), an essential molecule for life. However, whether these different precursors act in an additive or complementary manner is not truly well understood. Here, we have evaluated how combinations of different NAD+ precursors influence intracellular NAD+ levels. We identified dihydronicotinic acid riboside (NARH) as a new NAD+ precursor in hepatic cells. Second, we demonstrate how NARH, but not any other NAD+ precursor, can act synergistically with nicotinamide riboside (NR) to increase NAD+ levels in cultured cells and in mice. Finally, we demonstrate that the large increase in NAD+ prompted by the combination of these two precursors is due to their chemical interaction and conversion to dihydronicotinamide riboside (NRH). Altogether, this work demonstrates for the first time that NARH can act as a NAD+ precursor in mammalian cells and how different NAD+ precursors can interact and influence each other when co-administered.
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Odoh CK, Guo X, Arnone JT, Wang X, Zhao ZK. The role of NAD and NAD precursors on longevity and lifespan modulation in the budding yeast, Saccharomyces cerevisiae. Biogerontology 2022; 23:169-199. [PMID: 35260986 PMCID: PMC8904166 DOI: 10.1007/s10522-022-09958-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/16/2022] [Indexed: 11/26/2022]
Abstract
Molecular causes of aging and longevity interventions have witnessed an upsurge in the last decade. The resurgent interests in the application of small molecules as potential geroprotectors and/or pharmacogenomics point to nicotinamide adenine dinucleotide (NAD) and its precursors, nicotinamide riboside, nicotinamide mononucleotide, nicotinamide, and nicotinic acid as potentially intriguing molecules. Upon supplementation, these compounds have shown to ameliorate aging related conditions and possibly prevent death in model organisms. Besides being a molecule essential in all living cells, our understanding of the mechanism of NAD metabolism and its regulation remain incomplete owing to its omnipresent nature. Here we discuss recent advances and techniques in the study of chronological lifespan (CLS) and replicative lifespan (RLS) in the model unicellular organism Saccharomyces cerevisiae. We then follow with the mechanism and biology of NAD precursors and their roles in aging and longevity. Finally, we review potential biotechnological applications through engineering of microbial lifespan, and laid perspective on the promising candidature of alternative redox compounds for extending lifespan.
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Affiliation(s)
- Chuks Kenneth Odoh
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Rd, Dalian, 116023, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Xiaojia Guo
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Rd, Dalian, 116023, China
- Dalian Key Laboratory of Energy Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Rd, Dalian, 116023, China
| | - James T Arnone
- Department of Biology, William Paterson University, Wayne, NJ, 07470, USA
| | - Xueying Wang
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Rd, Dalian, 116023, China
- Dalian Key Laboratory of Energy Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Rd, Dalian, 116023, China
| | - Zongbao K Zhao
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Rd, Dalian, 116023, China.
- Dalian Key Laboratory of Energy Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Rd, Dalian, 116023, China.
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Groth B, Venkatakrishnan P, Lin SJ. NAD + Metabolism, Metabolic Stress, and Infection. Front Mol Biosci 2021; 8:686412. [PMID: 34095234 PMCID: PMC8171187 DOI: 10.3389/fmolb.2021.686412] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 05/05/2021] [Indexed: 12/26/2022] Open
Abstract
Nicotinamide adenine dinucleotide (NAD+) is an essential metabolite with wide-ranging and significant roles in the cell. Defects in NAD+ metabolism have been associated with many human disorders; it is therefore an emerging therapeutic target. Moreover, NAD+ metabolism is perturbed during colonization by a variety of pathogens, either due to the molecular mechanisms employed by these infectious agents or by the host immune response they trigger. Three main biosynthetic pathways, including the de novo and salvage pathways, contribute to the production of NAD+ with a high degree of conservation from bacteria to humans. De novo biosynthesis, which begins with l-tryptophan in eukaryotes, is also known as the kynurenine pathway. Intermediates of this pathway have various beneficial and deleterious effects on cellular health in different contexts. For example, dysregulation of this pathway is linked to neurotoxicity and oxidative stress. Activation of the de novo pathway is also implicated in various infections and inflammatory signaling. Given the dynamic flexibility and multiple roles of NAD+ intermediates, it is important to understand the interconnections and cross-regulations of NAD+ precursors and associated signaling pathways to understand how cells regulate NAD+ homeostasis in response to various growth conditions. Although regulation of NAD+ homeostasis remains incompletely understood, studies in the genetically tractable budding yeast Saccharomyces cerevisiae may help provide some molecular basis for how NAD+ homeostasis factors contribute to the maintenance and regulation of cellular function and how they are regulated by various nutritional and stress signals. Here we present a brief overview of recent insights and discoveries made with respect to the relationship between NAD+ metabolism and selected human disorders and infections, with a particular focus on the de novo pathway. We also discuss how studies in budding yeast may help elucidate the regulation of NAD+ homeostasis.
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Affiliation(s)
- Benjamin Groth
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, Davis, CA, United States
| | - Padmaja Venkatakrishnan
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, Davis, CA, United States
| | - Su-Ju Lin
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, Davis, CA, United States
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8
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Austin S, Mayer A. Phosphate Homeostasis - A Vital Metabolic Equilibrium Maintained Through the INPHORS Signaling Pathway. Front Microbiol 2020; 11:1367. [PMID: 32765429 PMCID: PMC7381174 DOI: 10.3389/fmicb.2020.01367] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 05/27/2020] [Indexed: 12/12/2022] Open
Abstract
Cells face major changes in demand for and supply of inorganic phosphate (Pi). Pi is often a limiting nutrient in the environment, particularly for plants and microorganisms. At the same time, the need for phosphate varies, establishing conflicts of goals. Cells experience strong peaks of Pi demand, e.g., during the S-phase, when DNA, a highly abundant and phosphate-rich compound, is duplicated. While cells must satisfy these Pi demands, they must safeguard themselves against an excess of Pi in the cytosol. This is necessary because Pi is a product of all nucleotide-hydrolyzing reactions. An accumulation of Pi shifts the equilibria of these reactions and reduces the free energy that they can provide to drive endergonic metabolic reactions. Thus, while Pi starvation may simply retard growth and division, an elevated cytosolic Pi concentration is potentially dangerous for cells because it might stall metabolism. Accordingly, the consequences of perturbed cellular Pi homeostasis are severe. In eukaryotes, they range from lethality in microorganisms such as yeast (Sethuraman et al., 2001; Hürlimann, 2009), severe growth retardation and dwarfism in plants (Puga et al., 2014; Liu et al., 2015; Wild et al., 2016) to neurodegeneration or renal Fanconi syndrome in humans (Legati et al., 2015; Ansermet et al., 2017). Intracellular Pi homeostasis is thus not only a fundamental topic of cell biology but also of growing interest for medicine and agriculture.
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Affiliation(s)
- Sisley Austin
- Département de Biochimie, Université de Lausanne, Lausanne, Switzerland
| | - Andreas Mayer
- Département de Biochimie, Université de Lausanne, Lausanne, Switzerland
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Wang S, Han J, Xia J, Hu Y, Shi L, Ren A, Zhu J, Zhao M. Overexpression of nicotinamide mononucleotide adenylyltransferase (nmnat) increases the growth rate, Ca 2+ concentration and cellulase production in Ganoderma lucidum. Appl Microbiol Biotechnol 2020; 104:7079-7091. [PMID: 32632475 DOI: 10.1007/s00253-020-10763-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 06/08/2020] [Accepted: 06/16/2020] [Indexed: 12/13/2022]
Abstract
Identifying new and economical means to utilize diverse lignocellulosic biomass is an urgent task. Ganoderma lucidum is a well-known edible and medicinal basidiomycete with an excellent ability to degrade a wide range of cellulosic biomass, and its nutrient use efficiency is closely related to the activity of extracellular cellulase. Intracellular nicotinamide adenine dinucleotide (NAD+) biosynthesis is controlled in response to nutritional status, and NAD+ is an essential metabolite involved in diverse cellular processes. Nicotinamide mononucleotide adenylyltransferase (NMNAT) is a common enzyme in three NAD+ synthesis pathways. In this study, a homologous gene of nmnat was cloned from G. lucidum and two G. lucidum overexpression strains, OE::nmnat4 and OE::nmnat19, were constructed using an Agrobacterium tumefaciens-mediated transformation method. The G. lucidum nmnat overexpression strains showed obviously increased colony growth on different carbon sources, and intracellular Ca2+ concentrations in the G. lucidum OE::nmnat4 and OE::nmnat19 strains were increased by 2.04- and 2.30-fold, respectively, compared with those in the wild-type (WT) strains. In the G. lucidum OE::nmnat4 and OE::nmnat19 strains, endo-β-glucanase (CMCase) activity increased by approximately 2.8- and 3-fold, while β-glucosidase (pNPGase) activity increased by approximately 1.9- and 2.1-fold, respectively, compared with the activity in the WT strains. Furthermore, overexpression of NAD+ synthesis pathways was found to elicit cellulase production by increasing the intracellular Ca2+ concentration. In summary, this study is the first to demonstrate that increased intracellular NAD+ contents through overexpression of the nmnat gene of NAD+ synthesis pathways may increase cellulase production by increasing intracellular Ca2+ concentrations in G. lucidum. KEY POINTS: • The concentration of NAD+influences cellulase production in G. lucidum. • The concentration of NAD+influences the intracellular Ca2+concentration in G. lucidum. • The concentration of NAD+influences cellulase production by eliciting a change in intracellular Ca2+in G. lucidum.
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Affiliation(s)
- Shengli Wang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, People's Republic of China
| | - Jing Han
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, People's Republic of China
| | - Jiale Xia
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, People's Republic of China
| | - Yanru Hu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, People's Republic of China
| | - Liang Shi
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, People's Republic of China
| | - Ang Ren
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, People's Republic of China
| | - Jing Zhu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, People's Republic of China
| | - Mingwen Zhao
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, People's Republic of China.
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Neamţu AS, Biţă A, Scorei IR, Rău G, Bejenaru LE, Bejenaru C, Rogoveanu OC, Oancea CN, Radu A, Pisoschi CG, Neamţu J, Mogoşanu GD. Simultaneous quantitation of nicotinamide riboside and nicotinamide in dietary supplements via HPTLC–UV with confirmation by online HPTLC–ESI–MS. ACTA CHROMATOGR 2020. [DOI: 10.1556/1326.2019.00600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The identification and quantitation of nicotinamide riboside (NAR) and its main related compound (nicotinamide) were achieved using high-performance thin-layer chromatography (HPTLC)–ultraviolet (UV) densitometry with confirmation by online electrospray ionization (ESI)–mass spectrometry (MS). As the stationary phase, HPTLC Si 60 F254 glass plates were employed; the mobile phase was ethanol–1 M ammonium acetate–formic acid (7:1:0.1, v/v/v). No derivatization was applied, and UV densitometry was performed in the absorbance mode (270 nm). The method was validated by specificity, linearity, accuracy, precision, and robustness.
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Affiliation(s)
- Andreea Silvia Neamţu
- 1 Doctoral School, University of Medicine and Pharmacy of Craiova, 2 Petru Rareş Street, 200349 Craiova, Dolj County, Romania
| | - Andrei Biţă
- 2 Department of Pharmacognosy & Phytotherapy, Faculty of Pharmacy, University of Medicine and Pharmacy of Craiova, 2 Petru Rareş Street, 200349 Craiova, Dolj County, Romania
| | - Ion Romulus Scorei
- 3 BioBoron Research Institute, S.C. Natural Research S.R.L., 31B Dunării Street, 207465 Podari Commune, Dolj County, Romania
| | - Gabriela Rău
- 4 Department of Organic Chemistry, Faculty of Pharmacy, University of Medicine and Pharmacy of Craiova, 2 Petru Rareş Street, 200349 Craiova, Dolj County, Romania
| | - Ludovic Everard Bejenaru
- 2 Department of Pharmacognosy & Phytotherapy, Faculty of Pharmacy, University of Medicine and Pharmacy of Craiova, 2 Petru Rareş Street, 200349 Craiova, Dolj County, Romania
| | - Cornelia Bejenaru
- 5 Department of Pharmaceutical Botany, Faculty of Pharmacy, University of Medicine and Pharmacy of Craiova, 2 Petru Rareş Street, 200349 Craiova, Dolj County, Romania
| | - Otilia-Constantina Rogoveanu
- 6 Department of Physical Medicine and Rehabilitation, Faculty of Medicine, University of Medicine and Pharmacy of Craiova, 2 Petru Rareş Street, 200349 Craiova, Dolj County, Romania
| | - Carmen Nicoleta Oancea
- 1 Doctoral School, University of Medicine and Pharmacy of Craiova, 2 Petru Rareş Street, 200349 Craiova, Dolj County, Romania
| | - Antonia Radu
- 5 Department of Pharmaceutical Botany, Faculty of Pharmacy, University of Medicine and Pharmacy of Craiova, 2 Petru Rareş Street, 200349 Craiova, Dolj County, Romania
| | - Cătălina Gabriela Pisoschi
- 7 Department of Biochemistry, Faculty of Pharmacy, University of Medicine and Pharmacy of Craiova2 Petru Rareş Street, 200349 Craiova, Dolj County, Romania
| | - Johny Neamţu
- 8 Department of Physics, Faculty of Pharmacy, University of Medicine and Pharmacy of Craiova2 Petru Rareş Street, 200349 Craiova, Dolj County, Romania
| | - George Dan Mogoşanu
- 2 Department of Pharmacognosy & Phytotherapy, Faculty of Pharmacy, University of Medicine and Pharmacy of Craiova, 2 Petru Rareş Street, 200349 Craiova, Dolj County, Romania
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Orlandi I, Alberghina L, Vai M. Nicotinamide, Nicotinamide Riboside and Nicotinic Acid-Emerging Roles in Replicative and Chronological Aging in Yeast. Biomolecules 2020; 10:E604. [PMID: 32326437 PMCID: PMC7226615 DOI: 10.3390/biom10040604] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 04/09/2020] [Accepted: 04/13/2020] [Indexed: 02/07/2023] Open
Abstract
Nicotinamide, nicotinic acid and nicotinamide riboside are vitamin B3 precursors of NAD+ in the human diet. NAD+ has a fundamental importance for cellular biology, that derives from its essential role as a cofactor of various metabolic redox reactions, as well as an obligate co-substrate for NAD+-consuming enzymes which are involved in many fundamental cellular processes including aging/longevity. During aging, a systemic decrease in NAD+ levels takes place, exposing the organism to the risk of a progressive inefficiency of those processes in which NAD+ is required and, consequently, contributing to the age-associated physiological/functional decline. In this context, dietary supplementation with NAD+ precursors is considered a promising strategy to prevent NAD+ decrease and attenuate in such a way several metabolic defects common to the aging process. The metabolism of NAD+ precursors and its impact on cell longevity have benefited greatly from studies performed in the yeast Saccharomyces cerevisiae, which is one of the most established model systems used to study the aging processes of both proliferating (replicative aging) and non-proliferating cells (chronological aging). In this review we summarize important aspects of the role played by nicotinamide, nicotinic acid and nicotinamide riboside in NAD+ metabolism and how each of these NAD+ precursors contribute to the different aspects that influence both replicative and chronological aging. Taken as a whole, the findings provided by the studies carried out in S. cerevisiae are informative for the understanding of the complex dynamic flexibility of NAD+ metabolism, which is essential for the maintenance of cellular fitness and for the development of dietary supplements based on NAD+ precursors.
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Affiliation(s)
- Ivan Orlandi
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, 2016 Milan, Italy;
| | | | - Marina Vai
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, 2016 Milan, Italy;
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12
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Perli T, Wronska AK, Ortiz‐Merino RA, Pronk JT, Daran J. Vitamin requirements and biosynthesis in Saccharomyces cerevisiae. Yeast 2020; 37:283-304. [PMID: 31972058 PMCID: PMC7187267 DOI: 10.1002/yea.3461] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 12/19/2019] [Accepted: 01/02/2020] [Indexed: 12/30/2022] Open
Abstract
Chemically defined media for yeast cultivation (CDMY) were developed to support fast growth, experimental reproducibility, and quantitative analysis of growth rates and biomass yields. In addition to mineral salts and a carbon substrate, popular CDMYs contain seven to nine B-group vitamins, which are either enzyme cofactors or precursors for their synthesis. Despite the widespread use of CDMY in fundamental and applied yeast research, the relation of their design and composition to the actual vitamin requirements of yeasts has not been subjected to critical review since their first development in the 1940s. Vitamins are formally defined as essential organic molecules that cannot be synthesized by an organism. In yeast physiology, use of the term "vitamin" is primarily based on essentiality for humans, but the genome of the Saccharomyces cerevisiae reference strain S288C harbours most of the structural genes required for synthesis of the vitamins included in popular CDMY. Here, we review the biochemistry and genetics of the biosynthesis of these compounds by S. cerevisiae and, based on a comparative genomics analysis, assess the diversity within the Saccharomyces genus with respect to vitamin prototrophy.
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Affiliation(s)
- Thomas Perli
- Department of BiotechnologyDelft University of TechnologyDelftThe Netherlands
| | - Anna K. Wronska
- Department of BiotechnologyDelft University of TechnologyDelftThe Netherlands
| | | | - Jack T. Pronk
- Department of BiotechnologyDelft University of TechnologyDelftThe Netherlands
| | - Jean‐Marc Daran
- Department of BiotechnologyDelft University of TechnologyDelftThe Netherlands
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13
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Croft T, Venkatakrishnan P, Lin SJ. NAD + Metabolism and Regulation: Lessons From Yeast. Biomolecules 2020; 10:E330. [PMID: 32092906 PMCID: PMC7072712 DOI: 10.3390/biom10020330] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 02/15/2020] [Accepted: 02/16/2020] [Indexed: 12/13/2022] Open
Abstract
Nicotinamide adenine dinucleotide (NAD+) is an essential metabolite involved in various cellular processes. The cellular NAD+ pool is maintained by three biosynthesis pathways, which are largely conserved from bacteria to human. NAD+ metabolism is an emerging therapeutic target for several human disorders including diabetes, cancer, and neuron degeneration. Factors regulating NAD+ homeostasis have remained incompletely understood due to the dynamic nature and complexity of NAD+ metabolism. Recent studies using the genetically tractable budding yeast Saccharomyces cerevisiae have identified novel NAD+ homeostasis factors. These findings help provide a molecular basis for how may NAD+ and NAD+ homeostasis factors contribute to the maintenance and regulation of cellular function. Here we summarize major NAD+ biosynthesis pathways, selected cellular processes that closely connect with and contribute to NAD+ homeostasis, and regulation of NAD+ metabolism by nutrient-sensing signaling pathways. We also extend the discussions to include possible implications of NAD+ homeostasis factors in human disorders. Understanding the cross-regulation and interconnections of NAD+ precursors and associated cellular pathways will help elucidate the mechanisms of the complex regulation of NAD+ homeostasis. These studies may also contribute to the development of effective NAD+-based therapeutic strategies specific for different types of NAD+ deficiency related disorders.
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Affiliation(s)
| | | | - Su-Ju Lin
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, CA 95616, USA; (T.C.); (P.V.)
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14
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Hikosaka K, Yaku K, Okabe K, Nakagawa T. Implications of NAD metabolism in pathophysiology and therapeutics for neurodegenerative diseases. Nutr Neurosci 2019; 24:371-383. [PMID: 31280708 DOI: 10.1080/1028415x.2019.1637504] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Nicotinamide adenine dinucleotide (NAD) is an essential coenzyme that mediates various redox reactions. Particularly, mitochondrial NAD plays a critical role in energy production pathways, including the tricarboxylic acid (TCA) cycle, fatty acid oxidation, and oxidative phosphorylation. NAD also serves as a substrate for ADP-ribosylation and deacetylation by poly(ADP-ribose) polymerases (PARPs) and sirtuins, respectively. Thus, NAD regulates energy metabolism, DNA damage repair, gene expression, and stress response. Numerous studies have demonstrated the involvement of NAD metabolism in neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), and retinal degenerative diseases. Mitochondrial dysfunction is considered crucial pathogenesis for neurodegenerative diseases such as AD and PD. Maintaining appropriate NAD levels is important for mitochondrial function. Indeed, decreased NAD levels are observed in AD and PD, and supplementation of NAD precursors ameliorates disease phenotypes by activating mitochondrial functions. NAD metabolism also plays an important role in axonal degeneration, a characteristic feature of peripheral neuropathy and neurodegenerative diseases. In addition, dysregulated NAD metabolism is implicated in retinal degenerative diseases such as glaucoma and Leber congenital amaurosis, and NAD metabolism is considered a therapeutic target for these diseases. In this review, we summarize the involvement of NAD metabolism in axon degeneration and various neurodegenerative diseases and discuss perspectives of nutritional intervention using NAD precursors.
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Affiliation(s)
- Keisuke Hikosaka
- Department of Metabolism and Nutrition, Graduate School of Medicine and Pharmaceutical Science for Research, University of Toyama, Toyama, Japan
| | - Keisuke Yaku
- Department of Metabolism and Nutrition, Graduate School of Medicine and Pharmaceutical Science for Research, University of Toyama, Toyama, Japan
| | - Keisuke Okabe
- Department of Metabolism and Nutrition, Graduate School of Medicine and Pharmaceutical Science for Research, University of Toyama, Toyama, Japan.,First Department of Internal Medicine, Graduate School of Medicine and Pharmaceutical Science for Research, University of Toyama, Toyama, Japan
| | - Takashi Nakagawa
- Department of Metabolism and Nutrition, Graduate School of Medicine and Pharmaceutical Science for Research, University of Toyama, Toyama, Japan.,Institute of Natural Medicine, University of Toyama, Toyama, Japan
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15
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Okabe K, Yaku K, Tobe K, Nakagawa T. Implications of altered NAD metabolism in metabolic disorders. J Biomed Sci 2019; 26:34. [PMID: 31078136 PMCID: PMC6511662 DOI: 10.1186/s12929-019-0527-8] [Citation(s) in RCA: 133] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 04/25/2019] [Indexed: 12/15/2022] Open
Abstract
Nicotinamide adenine dinucleotide (NAD) is an important coenzyme that participates in various energy metabolism pathways, including glycolysis, β-oxidation, and oxidative phosphorylation. Besides, it is a required cofactor for post-translational modifications such as ADP-ribosylation and deacetylation by poly (ADP-ribose) polymerases (PARPs) and sirtuins, respectively. Thus, NAD regulates energy metabolism, DNA damage repair, gene expression, and stress response through these enzymes. Numerous studies have shown that NAD levels decrease with aging and under disturbed nutrient conditions, such as obesity. Additionally, a decline in NAD levels is closely related to the development of various metabolic disorders, including diabetes and fatty liver disease. In addition, many studies have revealed that administration of NAD precursors, such as nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR), efficiently increase NAD levels in various tissues and prevent such metabolic diseases. These NAD precursors are contained in natural foods, such as cow milk, vegetables, and meats. Therefore, altered NAD metabolism can be a practical target for nutritional intervention. Recently, several human clinical trials using NAD precursors have been conducted to investigate the safety, pharmacokinetics, and efficacy against metabolic disorders such as glucose intolerance. In this review, we summarize current knowledge on the implications of NAD metabolism in metabolic diseases and discuss the outcomes of recent human clinical trials.
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Affiliation(s)
- Keisuke Okabe
- Department of Metabolism and Nutrition, Graduate School of Medicine and Pharmaceutical Science for Research, University of Toyama, 2630 Sugitani, Toyama, Toyama 930-0194 Japan
- First Department of Internal Medicine, Graduate School of Medicine and Pharmaceutical Science for Research, University of Toyama, Toyama, 930-0194 Japan
| | - Keisuke Yaku
- Department of Metabolism and Nutrition, Graduate School of Medicine and Pharmaceutical Science for Research, University of Toyama, 2630 Sugitani, Toyama, Toyama 930-0194 Japan
| | - Kazuyuki Tobe
- First Department of Internal Medicine, Graduate School of Medicine and Pharmaceutical Science for Research, University of Toyama, Toyama, 930-0194 Japan
| | - Takashi Nakagawa
- Department of Metabolism and Nutrition, Graduate School of Medicine and Pharmaceutical Science for Research, University of Toyama, 2630 Sugitani, Toyama, Toyama 930-0194 Japan
- Institute of Natural Medicine, University of Toyama, Toyama, 930-0194 Japan
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16
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James Theoga Raj C, Lin SJ. Cross-talk in NAD + metabolism: insights from Saccharomyces cerevisiae. Curr Genet 2019; 65:1113-1119. [PMID: 30993413 DOI: 10.1007/s00294-019-00972-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 04/11/2019] [Indexed: 02/07/2023]
Abstract
NAD+ (nicotinamide adenine dinucleotide) is an essential metabolite involved in a myriad of cellular processes. The NAD+ pool is maintained by three biosynthesis pathways, which are largely conserved from bacteria to human with some species-specific differences. Studying the regulation of NAD+ metabolism has been difficult due to the dynamic flexibility of NAD+ intermediates, the redundancy of biosynthesis pathways, and the complex interconnections among them. The budding yeast Saccharomyces cerevisiae provides an efficient genetic model for the isolation and study of factors that regulate specific NAD+ biosynthesis pathways. A recent study has uncovered a putative cross-regulation between the de novo NAD+ biosynthesis and copper homeostasis mediated by a copper-sensing transcription factor Mac1. Mac1 appears to work with the Hst1-Sum1-Rfm1 complex to repress the expression of de novo NAD+ biosynthesis genes. Here, we extend the discussions to include additional nutrient- and stress-sensing pathways that have been associated with the regulation of NAD+ homeostasis. NAD+ metabolism is an emerging therapeutic target for several human diseases. NAD+ preservation also helps ameliorate age-associated metabolic disorders. Recent findings in yeast contribute to the understanding of the molecular basis underlying the cross-regulation of NAD+ metabolism and other signaling pathways.
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Affiliation(s)
- Christol James Theoga Raj
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, One Shields Ave., Davis, CA, 95616, USA
| | - Su-Ju Lin
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, One Shields Ave., Davis, CA, 95616, USA.
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17
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Pinson B, Ceschin J, Saint-Marc C, Daignan-Fornier B. Dual control of NAD + synthesis by purine metabolites in yeast. eLife 2019; 8:43808. [PMID: 30860478 PMCID: PMC6430606 DOI: 10.7554/elife.43808] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 03/11/2019] [Indexed: 12/13/2022] Open
Abstract
Metabolism is a highly integrated process resulting in energy and biomass production. While individual metabolic routes are well characterized, the mechanisms ensuring crosstalk between pathways are poorly described, although they are crucial for homeostasis. Here, we establish a co-regulation of purine and pyridine metabolism in response to external adenine through two separable mechanisms. First, adenine depletion promotes transcriptional upregulation of the de novo NAD+ biosynthesis genes by a mechanism requiring the key-purine intermediates ZMP/SZMP and the Bas1/Pho2 transcription factors. Second, adenine supplementation favors the pyridine salvage route resulting in an ATP-dependent increase of intracellular NAD+. This control operates at the level of the nicotinic acid mononucleotide adenylyl-transferase Nma1 and can be bypassed by overexpressing this enzyme. Therefore, in yeast, pyridine metabolism is under the dual control of ZMP/SZMP and ATP, revealing a much wider regulatory role for these intermediate metabolites in an integrated biosynthesis network.
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Affiliation(s)
- Benoît Pinson
- IBGCUniversité de Bordeaux UMR 5095BordeauxFrance
- Centre National de la Recherche Scientifique IBGC UMR 5095BordeauxFrance
| | - Johanna Ceschin
- IBGCUniversité de Bordeaux UMR 5095BordeauxFrance
- Centre National de la Recherche Scientifique IBGC UMR 5095BordeauxFrance
| | - Christelle Saint-Marc
- IBGCUniversité de Bordeaux UMR 5095BordeauxFrance
- Centre National de la Recherche Scientifique IBGC UMR 5095BordeauxFrance
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18
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James Theoga Raj C, Croft T, Venkatakrishnan P, Groth B, Dhugga G, Cater T, Lin SJ. The copper-sensing transcription factor Mac1, the histone deacetylase Hst1, and nicotinic acid regulate de novo NAD + biosynthesis in budding yeast. J Biol Chem 2019; 294:5562-5575. [PMID: 30760525 DOI: 10.1074/jbc.ra118.006987] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 02/01/2019] [Indexed: 12/16/2022] Open
Abstract
NADH (NAD+) is an essential metabolite involved in various cellular biochemical processes. The regulation of NAD+ metabolism is incompletely understood. Here, using budding yeast (Saccharomyces cerevisiae), we established an NAD+ intermediate-specific genetic system to identify factors that regulate the de novo branch of NAD+ biosynthesis. We found that a mutant strain (mac1Δ) lacking Mac1, a copper-sensing transcription factor that activates copper transport genes during copper deprivation, exhibits increases in quinolinic acid (QA) production and NAD+ levels. Similar phenotypes were also observed in the hst1Δ strain, deficient in the NAD+-dependent histone deacetylase Hst1, which inhibits de novo NAD+ synthesis by repressing BNA gene expression when NAD+ is abundant. Interestingly, the mac1Δ and hst1Δ mutants shared a similar NAD+ metabolism-related gene expression profile, and deleting either MAC1 or HST1 de-repressed the BNA genes. ChIP experiments with the BNA2 promoter indicated that Mac1 works with Hst1-containing repressor complexes to silence BNA expression. The connection of Mac1 and BNA expression suggested that copper stress affects de novo NAD+ synthesis, and we show that copper stress induces both BNA expression and QA production. Moreover, nicotinic acid inhibited de novo NAD+ synthesis through Hst1-mediated BNA repression, hindered the reuptake of extracellular QA, and thereby reduced de novo NAD+ synthesis. In summary, we have identified and characterized novel NAD+ homeostasis factors. These findings will expand our understanding of the molecular basis and regulation of NAD+ metabolism.
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Affiliation(s)
- Christol James Theoga Raj
- From the Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, California 95616
| | - Trevor Croft
- From the Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, California 95616
| | - Padmaja Venkatakrishnan
- From the Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, California 95616
| | - Benjamin Groth
- From the Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, California 95616
| | - Gagandeep Dhugga
- From the Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, California 95616
| | - Timothy Cater
- From the Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, California 95616
| | - Su-Ju Lin
- From the Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, California 95616
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19
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Parzych KR, Klionsky DJ. Vacuolar hydrolysis and efflux: current knowledge and unanswered questions. Autophagy 2018; 15:212-227. [PMID: 30422029 DOI: 10.1080/15548627.2018.1545821] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Hydrolysis within the vacuole in yeast and the lysosome in mammals is required for the degradation and recycling of a multitude of substrates, many of which are delivered to the vacuole/lysosome by autophagy. In humans, defects in lysosomal hydrolysis and efflux can have devastating consequences, and contribute to a class of diseases referred to as lysosomal storage disorders. Despite the importance of these processes, many of the proteins and regulatory mechanisms involved in hydrolysis and efflux are poorly understood. In this review, we describe our current knowledge of the vacuolar/lysosomal degradation and efflux of a vast array of substrates, focusing primarily on what is known in the yeast Saccharomyces cerevisiae. We also highlight many unanswered questions, the answers to which may lead to new advances in the treatment of lysosomal storage disorders. Abbreviations: Ams1: α-mannosidase; Ape1: aminopeptidase I; Ape3: aminopeptidase Y; Ape4: aspartyl aminopeptidase; Atg: autophagy related; Cps1: carboxypeptidase S; CTNS: cystinosin, lysosomal cystine transporter; CTSA: cathepsin A; CTSD: cathepsin D; Cvt: cytoplasm-to-vacuole targeting; Dap2: dipeptidyl aminopeptidase B; GS-bimane: glutathione-S-bimane; GSH: glutathione; LDs: lipid droplets; MVB: multivesicular body; PAS: phagophore assembly site; Pep4: proteinase A; PolyP: polyphosphate; Prb1: proteinase B; Prc1: carboxypeptidase Y; V-ATPase: vacuolar-type proton-translocating ATPase; VTC: vacuolar transporter chaperone.
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Affiliation(s)
- Katherine R Parzych
- a Life Sciences Institute, and Department of Molecular, Cellular and Developmental Biology , University of Michigan , Ann Arbor , MI , USA
| | - Daniel J Klionsky
- a Life Sciences Institute, and Department of Molecular, Cellular and Developmental Biology , University of Michigan , Ann Arbor , MI , USA
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20
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Functional Characterization of the Saccharomyces cerevisiae Equilibrative Nucleoside Transporter 1 (ScENT1). Molecules 2018; 23:molecules23040732. [PMID: 29565807 PMCID: PMC6017673 DOI: 10.3390/molecules23040732] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 03/07/2018] [Accepted: 03/14/2018] [Indexed: 02/06/2023] Open
Abstract
Equilibrative nucleoside transporters (ENTs) are polytopic membrane transporters responsible for the translocation of nucleosides, nucleobases—to a lesser extent—and nucleoside analog therapeutics across cellular membranes. ENTs function in a diffusion controlled bidirectional manner and are thought to utilize an alternating access transport mechanism. However, a detailed understanding of ENT function at the molecular level has remained elusive. ScENT1 (formerly known as Function Unknown Now 26 or FUN26) is the only known ENT ortholog endogenously expressed in S. cerevisiae, and a proteoliposome assay system was used to study homogenously overexpressed and purified ScENT1 (wildtype relative to L390A and F249I mutants). L390 and F249 are highly conserved residues and were found to alter transporter function. L390A produced a reduction of mean transport activity while F249I increased mean substrate translocation relative to wildtype protein. However, both mutations resulted in transport of UTP—a novel gain of function for any ENT. These residues were then mapped onto an ab initio model of FUN26 which suggests they function in substrate translocation (L390) or cytoplasmic gating (F249). Furthermore, wildtype, L390A, and F249I were found to be sensitive to the presence of alcohols. Ethanol attenuated ScENT1-mediated transport of uridine by ~50%. These findings further demonstrate functional similarities between ScENT1 and human ENT isoforms and support identification of FUN26 as ScENT1, the first ENT isoform in S. cerevisiae.
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21
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Miyagawa A, Tatsumi S, Takahama W, Fujii O, Nagamoto K, Kinoshita E, Nomura K, Ikuta K, Fujii T, Hanazaki A, Kaneko I, Segawa H, Miyamoto KI. The sodium phosphate cotransporter family and nicotinamide phosphoribosyltransferase contribute to the daily oscillation of plasma inorganic phosphate concentration. Kidney Int 2018; 93:1073-1085. [PMID: 29398136 DOI: 10.1016/j.kint.2017.11.022] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 11/07/2017] [Accepted: 11/16/2017] [Indexed: 12/31/2022]
Abstract
Circulating inorganic phosphate exhibits a remarkable daily oscillation based on food intake. In humans and rodents, the daily oscillation in response to food intake may be coordinated to control the intestinal absorption, renal excretion, cellular shifts, and extracellular concentration of inorganic phosphate. However, mechanisms regulating the resulting oscillation are unknown. Here we investigated the roles of the sodium phosphate cotransporter SLC34 (Npt2) family and nicotinamide phosphoribosyltransferase (Nampt) in the daily oscillation of plasma inorganic phosphate levels. First, it is roughly linked to urinary inorganic phosphate excretion. Second, expression of renal Npt2a and Npt2c, and intestinal Npt2b proteins also exhibit a dynamic daily oscillation. Analyses of Npt2a, Npt2b, and Npt2c knockout mice revealed the importance of renal inorganic phosphate reabsorption and cellular inorganic phosphate shifts in the daily oscillation. Third, experiments in which nicotinamide and a specific Nampt inhibitor (FK866) were administered in the active and rest phases revealed that the Nampt/NAD+ system is involved in renal inorganic phosphate excretion. Additionally, for cellular shifts, liver-specific Nampt deletion disturbed the daily oscillation of plasma phosphate during the rest but not the active phase. In systemic Nampt+/- mice, NAD levels were significantly reduced in the liver, kidney, and intestine, and the daily oscillation (active and rest phases) of the plasma phosphate concentration was attenuated. Thus, the Nampt/NAD+ system for Npt2 regulation and cellular shifts to tissues such as the liver play an important role in generating daily oscillation of plasma inorganic phosphate levels.
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Affiliation(s)
- Atsumi Miyagawa
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Sawako Tatsumi
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan.
| | - Wako Takahama
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Osamu Fujii
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Kenta Nagamoto
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Emi Kinoshita
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Kengo Nomura
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Kayo Ikuta
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Toru Fujii
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Ai Hanazaki
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Ichiro Kaneko
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Hiroko Segawa
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Ken-Ichi Miyamoto
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan.
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22
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Croft T, James Theoga Raj C, Salemi M, Phinney BS, Lin SJ. A functional link between NAD + homeostasis and N-terminal protein acetylation in Saccharomyces cerevisiae. J Biol Chem 2018; 293:2927-2938. [PMID: 29317496 DOI: 10.1074/jbc.m117.807214] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 12/15/2017] [Indexed: 12/12/2022] Open
Abstract
Nicotinamide adenine dinucleotide (NAD+) is an essential metabolite participating in cellular redox chemistry and signaling, and the complex regulation of NAD+ metabolism is not yet fully understood. To investigate this, we established a NAD+-intermediate specific reporter system to identify factors required for salvage of metabolically linked nicotinamide (NAM) and nicotinic acid (NA). Mutants lacking components of the NatB complex, NAT3 and MDM20, appeared as hits in this screen. NatB is an Nα-terminal acetyltransferase responsible for acetylation of the N terminus of specific Met-retained peptides. In NatB mutants, increased NA/NAM levels were concomitant with decreased NAD+ We identified the vacuolar pool of nicotinamide riboside (NR) as the source of this increased NA/NAM. This NR pool is increased by nitrogen starvation, suggesting NAD+ and related metabolites may be trafficked to the vacuole for recycling. Supporting this, increased NA/NAM release in NatB mutants was abolished by deleting the autophagy protein ATG14 We next examined Tpm1 (tropomyosin), whose function is regulated by NatB-mediated acetylation, and Tpm1 overexpression (TPM1-oe) was shown to restore some NatB mutant defects. Interestingly, although TPM1-oe largely suppressed NA/NAM release in NatB mutants, it did not restore NAD+ levels. We showed that decreased nicotinamide mononucleotide adenylyltransferase (Nma1/Nma2) levels probably caused the NAD+ defects, and NMA1-oe was sufficient to restore NAD+ NatB-mediated N-terminal acetylation of Nma1 and Nma2 appears essential for maintaining NAD+ levels. In summary, our results support a connection between NatB-mediated protein acetylation and NAD+ homeostasis. Our findings may contribute to understanding the molecular basis and regulation of NAD+ metabolism.
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Affiliation(s)
- Trevor Croft
- Department of Microbiology and Molecular Genetics, College of Biological Sciences
| | | | - Michelle Salemi
- Proteomic Core Facility, University of California, Davis, California 95616
| | - Brett S Phinney
- Proteomic Core Facility, University of California, Davis, California 95616
| | - Su-Ju Lin
- Department of Microbiology and Molecular Genetics, College of Biological Sciences.
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23
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Kynurenine aminotransferase activity of Aro8/Aro9 engage tryptophan degradation by producing kynurenic acid in Saccharomyces cerevisiae. Sci Rep 2017; 7:12180. [PMID: 28939805 PMCID: PMC5610271 DOI: 10.1038/s41598-017-12392-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 09/07/2017] [Indexed: 12/12/2022] Open
Abstract
Kynurenic acid (KA) is a tryptophan (Trp) metabolite that is synthesised in a branch of kynurenine (KYN) pathway. KYN aminotransferase (KAT) catalyses deamination of KYN, yielding KA. Although KA synthesis is evolutionarily conserved from bacteria to humans, the cellular benefits of synthesising KA are unclear. In this study, we constructed a KAT-null yeast mutant defective in KA synthesis to clarify the cellular function of KA. Amino acid sequence analysis and LC/MS quantification of KA revealed that Aro8 and Aro9 are the major KATs. KA was significantly decreased in the aro8Δ aro9Δ double mutant. We found that aro8Δ aro9Δ cells did not exhibit obvious defects in growth or oxidative stress response when proper amounts of amino acids are supplied in the media. We further found that aro8Δ aro9Δ cells were sensitive to excess Trp. The Trp sensitivity was not rescued by addition of KA, suggesting that Trp sensitivity is not due to the loss of KA. In conclusion, we propose that KAT activity is required for detoxification of Trp by converting it to the less toxic KA.
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24
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Boswell-Casteel RC, Johnson JM, Roe-Žurž Z, Duggan KD, Schmitz H, Hays FA. Expression and purification of human and Saccharomyces cerevisiae equilibrative nucleoside transporters. Protein Expr Purif 2017; 142:68-74. [PMID: 28918196 DOI: 10.1016/j.pep.2017.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 09/05/2017] [Accepted: 09/05/2017] [Indexed: 01/09/2023]
Abstract
Nucleosides play an essential role in the physiology of eukaryotes by acting as metabolic precursors in de novo nucleic acid synthesis and energy metabolism. Nucleosides also act as ligands for purinergic receptors. Equilibrative nucleoside transporters (ENTs) are polytopic integral membrane proteins that aid in regulating plasmalemmal flux of purine and pyrimidine nucleosides and nucleobases. ENTs exhibit broad substrate selectivity across different isoforms and utilize diverse mechanisms to drive substrate flux across membranes. However, the molecular mechanisms and chemical determinants of ENT-mediated substrate recognition, binding, inhibition, and transport are poorly understood. To determine how ENT-mediated transport occurs at the molecular level, greater chemical insight and assays employing purified protein are essential. This article focuses on the expression and purification of human ENT1, human ENT2, and Saccharomyces cerevisiae ScENT1 using novel expression and purification strategies to isolate recombinant ENTs. ScENT1, hENT1, and hENT2 were expressed in W303 Saccharomyces cerevisiae cells and detergent solubilized from the membrane. After detergent extraction, these ENTs were further purified using immobilized metal affinity chromatography and size exclusion chromatography. This effort resulted in obtaining quantities of purified protein sufficient for future biophysical analysis.
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Affiliation(s)
- Rebba C Boswell-Casteel
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Jennifer M Johnson
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Zygy Roe-Žurž
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA 94143, USA
| | - Kelli D Duggan
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Hannah Schmitz
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Franklin A Hays
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Stephenson Oklahoma Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
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Pho4 Is Essential for Dissemination of Cryptococcus neoformans to the Host Brain by Promoting Phosphate Uptake and Growth at Alkaline pH. mSphere 2017; 2:mSphere00381-16. [PMID: 28144629 PMCID: PMC5266496 DOI: 10.1128/msphere.00381-16] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 12/30/2016] [Indexed: 12/30/2022] Open
Abstract
Phosphate acquisition by fungi is regulated by the phosphate-sensing and acquisition (PHO) signaling pathway. Cryptococcus neoformans disseminates from the lung to the brain and is the commonest cause of fungal meningitis worldwide. To investigate the contribution of PHO signaling to cryptococcal dissemination, we characterized a transcription factor knockout strain (hlh3Δ/pho4Δ) defective in phosphate acquisition. Despite little similarity with other fungal Pho4 proteins, Hlh3/Pho4 functioned like a typical phosphate-responsive transcription factor in phosphate-deprived cryptococci, accumulating in nuclei and triggering expression of genes involved in phosphate acquisition. The pho4Δ mutant strain was susceptible to a number of stresses, the effect of which, except for alkaline pH, was alleviated by phosphate supplementation. Even in the presence of phosphate, the PHO pathway was activated in wild-type cryptococci at or above physiological pH, and under these conditions, the pho4Δ mutant had a growth defect and compromised phosphate uptake. The pho4Δ mutant was hypovirulent in a mouse inhalation model, where dissemination to the brain was reduced dramatically, and markedly hypovirulent in an intravenous dissemination model. The pho4Δ mutant was not detected in blood, nor did it proliferate significantly when cultured with peripheral blood monocytes. In conclusion, dissemination of infection and the pathogenesis of meningitis are dependent on cryptococcal phosphate uptake and stress tolerance at alkaline pH, both of which are Pho4 dependent. IMPORTANCE Cryptococcal meningitis is fatal without treatment and responsible for more than 500,000 deaths annually. To be a successful pathogen, C. neoformans must obtain an adequate supply of essential nutrients, including phosphate, from various host niches. Phosphate acquisition in fungi is regulated by the PHO signaling cascade, which is activated when intracellular phosphate decreases below a critical level. Induction of phosphate acquisition genes leads to the uptake of free phosphate via transporters. By blocking the PHO pathway using a Pho4 transcription factor mutant (pho4Δ mutant), we demonstrate the importance of the pathway for cryptococcal dissemination and the establishment of brain infection in murine models. Specifically, we show that reduced dissemination of the pho4Δ mutant to the brain is due to an alkaline pH tolerance defect, as alkaline pH mimics the conditions of phosphate deprivation. The end result is inhibited proliferation in host tissues, particularly in blood.
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Cfs1p, a Novel Membrane Protein in the PQ-Loop Family, Is Involved in Phospholipid Flippase Functions in Yeast. G3-GENES GENOMES GENETICS 2017; 7:179-192. [PMID: 28057802 PMCID: PMC5217107 DOI: 10.1534/g3.116.035238] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Type 4 P-type ATPases (P4-ATPases) function as phospholipid flippases, which translocate phospholipids from the exoplasmic leaflet to the cytoplasmic leaflet of the lipid bilayer, to generate and maintain asymmetric distribution of phospholipids at the plasma membrane and endosomal/Golgi membranes. The budding yeast Saccharomyces cerevisiae has four heteromeric flippases (Drs2p, Dnf1p, Dnf2p, and Dnf3p), associated with the Cdc50p family noncatalytic subunit, and one monomeric flippase, Neo1p. They have been suggested to function in vesicle formation in membrane trafficking pathways, but details of their mechanisms remain to be clarified. Here, to search for novel factors that functionally interact with flippases, we screened transposon insertional mutants for strains that suppressed the cold-sensitive growth defect in the cdc50Δ mutant. We identified a mutation of YMR010W encoding a novel conserved membrane protein that belongs to the PQ-loop family including the cystine transporter cystinosin and the SWEET sugar transporters. We named this gene CFS1 (cdc fifty suppressor 1). GFP-tagged Cfs1p was partially colocalized with Drs2p and Neo1p to endosomal/late Golgi membranes. Interestingly, the cfs1Δ mutation suppressed growth defects in all flippase mutants. Accordingly, defects in membrane trafficking in the flippase mutants were also suppressed. These results suggest that Cfs1p and flippases function antagonistically in membrane trafficking pathways. A growth assay to assess sensitivity to duramycin, a phosphatidylethanolamine (PE)-binding peptide, suggested that the cfs1Δ mutation changed PE asymmetry in the plasma membrane. Cfs1p may thus be a novel regulator of phospholipid asymmetry.
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Mericskay M. Nicotinamide adenine dinucleotide homeostasis and signalling in heart disease: Pathophysiological implications and therapeutic potential. Arch Cardiovasc Dis 2015; 109:207-15. [PMID: 26707577 DOI: 10.1016/j.acvd.2015.10.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 10/07/2015] [Accepted: 10/09/2015] [Indexed: 12/31/2022]
Abstract
Heart failure is a highly morbid syndrome generating enormous socio-economic costs. The failing heart is characterized by a state of deficient bioenergetics that is not currently addressed by classical clinical approaches. Nicotinamide adenine dinucleotide (NAD(+)/NADH) is a major coenzyme for oxidoreduction reactions in energy metabolism; it has recently emerged as a signalling molecule with a broad range of activities, ranging from calcium (Ca(2+)) signalling (CD38 ectoenzyme) to the epigenetic regulation of gene expression involved in the oxidative stress response, catabolic metabolism and mitochondrial biogenesis (sirtuins, poly[adenosine diphosphate-ribose] polymerases [PARPs]). Here, we review current knowledge regarding alterations to myocardial NAD homeostasis that have been observed in various models of heart failure, and their effect on mitochondrial functions, Ca(2+), sirtuin and PARP signalling. We highlight the therapeutic approaches that are currently in use or in development, which inhibit or stimulate NAD(+)-consuming enzymes, and emerging approaches aimed at stimulating NAD biosynthesis in the failing heart.
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Affiliation(s)
- Mathias Mericskay
- CNRS UMR8256-Inserm U1164, Biology of Adaptation and Ageing, Institute of Biology Paris-Seine, University Pierre-and-Marie-Curie Paris 6, 7, quai Saint-Bernard, 75005 Paris, France.
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Kulikova V, Shabalin K, Nerinovski K, Dölle C, Niere M, Yakimov A, Redpath P, Khodorkovskiy M, Migaud ME, Ziegler M, Nikiforov A. Generation, Release, and Uptake of the NAD Precursor Nicotinic Acid Riboside by Human Cells. J Biol Chem 2015; 290:27124-27137. [PMID: 26385918 DOI: 10.1074/jbc.m115.664458] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Indexed: 12/31/2022] Open
Abstract
NAD is essential for cellular metabolism and has a key role in various signaling pathways in human cells. To ensure proper control of vital reactions, NAD must be permanently resynthesized. Nicotinamide and nicotinic acid as well as nicotinamide riboside (NR) and nicotinic acid riboside (NAR) are the major precursors for NAD biosynthesis in humans. In this study, we explored whether the ribosides NR and NAR can be generated in human cells. We demonstrate that purified, recombinant human cytosolic 5'-nucleotidases (5'-NTs) CN-II and CN-III, but not CN-IA, can dephosphorylate the mononucleotides nicotinamide mononucleotide and nicotinic acid mononucleotide (NAMN) and thus catalyze NR and NAR formation in vitro. Similar to their counterpart from yeast, Sdt1, the human 5'-NTs require high (millimolar) concentrations of nicotinamide mononucleotide or NAMN for efficient catalysis. Overexpression of FLAG-tagged CN-II and CN-III in HEK293 and HepG2 cells resulted in the formation and release of NAR. However, NAR accumulation in the culture medium of these cells was only detectable under conditions that led to increased NAMN production from nicotinic acid. The amount of NAR released from cells engineered for increased NAMN production was sufficient to maintain viability of surrounding cells unable to use any other NAD precursor. Moreover, we found that untransfected HeLa cells produce and release sufficient amounts of NAR and NR under normal culture conditions. Collectively, our results indicate that cytosolic 5'-NTs participate in the conversion of NAD precursors and establish NR and NAR as integral constituents of human NAD metabolism. In addition, they point to the possibility that different cell types might facilitate each other's NAD supply by providing alternative precursors.
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Affiliation(s)
- Veronika Kulikova
- Peter the Great St. Petersburg Polytechnic University, St. Petersburg 195251, Russia
| | - Konstantin Shabalin
- Peter the Great St. Petersburg Polytechnic University, St. Petersburg 195251, Russia,; Petersburg Nuclear Physics Institute, National Research Centre Kurchatov Institute, Gatchina 188300, Russia
| | - Kirill Nerinovski
- Peter the Great St. Petersburg Polytechnic University, St. Petersburg 195251, Russia,; St. Petersburg State University, St. Petersburg 199034, Russia
| | - Christian Dölle
- Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway
| | - Marc Niere
- Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway
| | - Alexander Yakimov
- Peter the Great St. Petersburg Polytechnic University, St. Petersburg 195251, Russia,; Petersburg Nuclear Physics Institute, National Research Centre Kurchatov Institute, Gatchina 188300, Russia
| | - Philip Redpath
- School of Pharmacy, Queen's University Belfast, Belfast BT9 7BL, Northern Ireland, United Kingdom
| | - Mikhail Khodorkovskiy
- Peter the Great St. Petersburg Polytechnic University, St. Petersburg 195251, Russia
| | - Marie E Migaud
- School of Pharmacy, Queen's University Belfast, Belfast BT9 7BL, Northern Ireland, United Kingdom
| | - Mathias Ziegler
- Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway,.
| | - Andrey Nikiforov
- Peter the Great St. Petersburg Polytechnic University, St. Petersburg 195251, Russia,; Institute of Cytology, Russian Academy of Sciences, St. Petersburg 194064, Russia.
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Tsang F, Lin SJ. Less is more: Nutrient limitation induces cross-talk of nutrient sensing pathways with NAD + homeostasis and contributes to longevity. ACTA ACUST UNITED AC 2015; 10:333-357. [PMID: 27683589 DOI: 10.1007/s11515-015-1367-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Nutrient sensing pathways and their regulation grant cells control over their metabolism and growth in response to changing nutrients. Factors that regulate nutrient sensing can also modulate longevity. Reduced activity of nutrient sensing pathways such as glucose-sensing PKA, nitrogen-sensing TOR and S6 kinase homolog Sch9 have been linked to increased life span in the yeast, Saccharomyces cerevisiae, and higher eukaryotes. Recently, reduced activity of amino acid sensing SPS pathway was also shown to increase yeast life span. Life span extension by reduced SPS activity requires enhanced NAD+ (nicotinamide adenine dinucleotide, oxidized form) and nicotinamide riboside (NR, a NAD+ precursor) homeostasis. Maintaining adequate NAD+ pools has been shown to play key roles in life span extension, but factors regulating NAD+ metabolism and homeostasis are not completely understood. Recently, NAD+ metabolism was also linked to the phosphate (Pi)-sensing PHO pathway in yeast. Canonical PHO activation requires Pi-starvation. Interestingly, NAD+ depletion without Pi-starvation was sufficient to induce PHO activation, increasing NR production and mobilization. Moreover, SPS signaling appears to function in parallel with PHO signaling components to regulate NR/NAD+ homeostasis. These studies suggest that NAD+ metabolism is likely controlled by and/or coordinated with multiple nutrient sensing pathways. Indeed, cross-regulation of PHO, PKA, TOR and Sch9 pathways was reported to potentially affect NAD+ metabolism; though detailed mechanisms remain unclear. This review discusses yeast longevity-related nutrient sensing pathways and possible mechanisms of life span extension, regulation of NAD+ homeostasis, and cross-talk among nutrient sensing pathways and NAD+ homeostasis.
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Affiliation(s)
- Felicia Tsang
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, CA 95616, USA
| | - Su-Ju Lin
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, CA 95616, USA
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Nikiforov A, Kulikova V, Ziegler M. The human NAD metabolome: Functions, metabolism and compartmentalization. Crit Rev Biochem Mol Biol 2015; 50:284-97. [PMID: 25837229 PMCID: PMC4673589 DOI: 10.3109/10409238.2015.1028612] [Citation(s) in RCA: 162] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The metabolism of NAD has emerged as a key regulator of cellular and organismal homeostasis. Being a major component of both bioenergetic and signaling pathways, the molecule is ideally suited to regulate metabolism and major cellular events. In humans, NAD is synthesized from vitamin B3 precursors, most prominently from nicotinamide, which is the degradation product of all NAD-dependent signaling reactions. The scope of NAD-mediated regulatory processes is wide including enzyme regulation, control of gene expression and health span, DNA repair, cell cycle regulation and calcium signaling. In these processes, nicotinamide is cleaved from NAD+ and the remaining ADP-ribosyl moiety used to modify proteins (deacetylation by sirtuins or ADP-ribosylation) or to generate calcium-mobilizing agents such as cyclic ADP-ribose. This review will also emphasize the role of the intermediates in the NAD metabolome, their intra- and extra-cellular conversions and potential contributions to subcellular compartmentalization of NAD pools.
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Affiliation(s)
- Andrey Nikiforov
- a Institute of Nanobiotechnologies, St. Petersburg State Polytechnical University , St. Petersburg , Russia .,b Institute of Cytology, Russian Academy of Sciences , St. Petersburg , Russia , and
| | - Veronika Kulikova
- a Institute of Nanobiotechnologies, St. Petersburg State Polytechnical University , St. Petersburg , Russia
| | - Mathias Ziegler
- c Department of Molecular Biology , University of Bergen , Bergen , Norway
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31
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Tsang F, James C, Kato M, Myers V, Ilyas I, Tsang M, Lin SJ. Reduced Ssy1-Ptr3-Ssy5 (SPS) signaling extends replicative life span by enhancing NAD+ homeostasis in Saccharomyces cerevisiae. J Biol Chem 2015; 290:12753-64. [PMID: 25825491 DOI: 10.1074/jbc.m115.644534] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Indexed: 12/15/2022] Open
Abstract
Attenuated nutrient signaling extends the life span in yeast and higher eukaryotes; however, the mechanisms are not completely understood. Here we identify the Ssy1-Ptr3-Ssy5 (SPS) amino acid sensing pathway as a novel longevity factor. A null mutation of SSY5 (ssy5Δ) increases replicative life span (RLS) by ∼50%. Our results demonstrate that several NAD(+) homeostasis factors play key roles in this life span extension. First, expression of the putative malate-pyruvate NADH shuttle increases in ssy5Δ cells, and deleting components of this shuttle, MAE1 and OAC1, largely abolishes RLS extension. Next, we show that Stp1, a transcription factor of the SPS pathway, directly binds to the promoter of MAE1 and OAC1 to regulate their expression. Additionally, deletion of SSY5 increases nicotinamide riboside (NR) levels and phosphate-responsive (PHO) signaling activity, suggesting that ssy5Δ increases NR salvaging. This increase contributes to NAD(+) homeostasis, partially ameliorating the NAD(+) deficiency and rescuing the short life span of the npt1Δ mutant. Moreover, we observed that vacuolar phosphatase, Pho8, is partially required for ssy5Δ-mediated NR increase and RLS extension. Together, our studies present evidence that supports SPS signaling is a novel NAD(+) homeostasis factor and ssy5Δ-mediated life span extension is likely due to concomitantly increased mitochondrial and vacuolar function. Our findings may contribute to understanding the molecular basis of NAD(+) metabolism, cellular life span, and diseases associated with NAD(+) deficiency and aging.
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Affiliation(s)
- Felicia Tsang
- From the Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, California 95616
| | - Christol James
- From the Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, California 95616
| | - Michiko Kato
- From the Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, California 95616
| | - Victoria Myers
- From the Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, California 95616
| | - Irtqa Ilyas
- From the Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, California 95616
| | - Matthew Tsang
- From the Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, California 95616
| | - Su-Ju Lin
- From the Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, California 95616
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32
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Huang H, Kawamata T, Horie T, Tsugawa H, Nakayama Y, Ohsumi Y, Fukusaki E. Bulk RNA degradation by nitrogen starvation-induced autophagy in yeast. EMBO J 2014; 34:154-68. [PMID: 25468960 DOI: 10.15252/embj.201489083] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Autophagy is a catabolic process conserved among eukaryotes. Under nutrient starvation, a portion of the cytoplasm is non-selectively sequestered into autophagosomes. Consequently, ribosomes are delivered to the vacuole/lysosome for destruction, but the precise mechanism of autophagic RNA degradation and its physiological implications for cellular metabolism remain unknown. We characterized autophagy-dependent RNA catabolism using a combination of metabolome and molecular biological analyses in yeast. RNA delivered to the vacuole was processed by Rny1, a T2-type ribonuclease, generating 3'-NMPs that were immediately converted to nucleosides by the vacuolar non-specific phosphatase Pho8. In the cytoplasm, these nucleosides were broken down by the nucleosidases Pnp1 and Urh1. Most of the resultant bases were not re-assimilated, but excreted from the cell. Bulk non-selective autophagy causes drastic perturbation of metabolism, which must be minimized to maintain intracellular homeostasis.
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Affiliation(s)
- Hanghang Huang
- Department of Biotechnology, Osaka University, Suita Osaka, Japan
| | - Tomoko Kawamata
- Frontier Research Center, Tokyo Institute of Technology, Midori-ku Yokohama, Japan
| | - Tetsuro Horie
- Frontier Research Center, Tokyo Institute of Technology, Midori-ku Yokohama, Japan
| | - Hiroshi Tsugawa
- Department of Biotechnology, Osaka University, Suita Osaka, Japan
| | | | - Yoshinori Ohsumi
- Frontier Research Center, Tokyo Institute of Technology, Midori-ku Yokohama, Japan
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Kato M, Lin SJ. Regulation of NAD+ metabolism, signaling and compartmentalization in the yeast Saccharomyces cerevisiae. DNA Repair (Amst) 2014; 23:49-58. [PMID: 25096760 DOI: 10.1016/j.dnarep.2014.07.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 06/06/2014] [Accepted: 07/11/2014] [Indexed: 12/21/2022]
Abstract
Pyridine nucleotides are essential coenzymes in many cellular redox reactions in all living systems. In addition to functioning as a redox carrier, NAD(+) is also a required co-substrate for the conserved sirtuin deacetylases. Sirtuins regulate transcription, genome maintenance and metabolism and function as molecular links between cells and their environment. Maintaining NAD(+) homeostasis is essential for proper cellular function and aberrant NAD(+) metabolism has been implicated in a number of metabolic- and age-associated diseases. Recently, NAD(+) metabolism has been linked to the phosphate-responsive signaling pathway (PHO pathway) in the budding yeast Saccharomyces cerevisiae. Activation of the PHO pathway is associated with the production and mobilization of the NAD(+) metabolite nicotinamide riboside (NR), which is mediated in part by PHO-regulated nucleotidases. Cross-regulation between NAD(+) metabolism and the PHO pathway has also been reported; however, detailed mechanisms remain to be elucidated. The PHO pathway also appears to modulate the activities of common downstream effectors of multiple nutrient-sensing pathways (Ras-PKA, TOR, Sch9/AKT). These signaling pathways were suggested to play a role in calorie restriction-mediated beneficial effects, which have also been linked to Sir2 function and NAD(+) metabolism. Here, we discuss the interactions of these pathways and their potential roles in regulating NAD(+) metabolism. In eukaryotic cells, intracellular compartmentalization facilitates the regulation of enzymatic functions and also concentrates or sequesters specific metabolites. Various NAD(+)-mediated cellular functions such as mitochondrial oxidative phosphorylation are compartmentalized. Therefore, we also discuss several key players functioning in mitochondrial, cytosolic and vacuolar compartmentalization of NAD(+) intermediates, and their potential roles in NAD(+) homeostasis. To date, it remains unclear how NAD(+) and NAD(+) intermediates shuttle between different cellular compartments. Together, these studies provide a molecular basis for how NAD(+) homeostasis factors and the interacting signaling pathways confer metabolic flexibility and contribute to maintaining cell fitness and genome stability.
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Affiliation(s)
- Michiko Kato
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, One Shields Ave., Davis, CA 95616, USA
| | - Su-Ju Lin
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, One Shields Ave., Davis, CA 95616, USA.
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Boswell-Casteel RC, Johnson JM, Duggan KD, Roe-Žurž Z, Schmitz H, Burleson C, Hays FA. FUN26 (function unknown now 26) protein from saccharomyces cerevisiae is a broad selectivity, high affinity, nucleoside and nucleobase transporter. J Biol Chem 2014; 289:24440-51. [PMID: 25035431 DOI: 10.1074/jbc.m114.553503] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Equilibrative nucleoside transporters (ENTs) are polytopic integral membrane proteins that transport nucleosides and, to a lesser extent, nucleobases across cell membranes. ENTs modulate efficacy for a range of human therapeutics and function in a diffusion-controlled bidirectional manner. A detailed understanding of ENT function at the molecular level has remained elusive. FUN26 (function unknown now 26) is a putative ENT homolog from S. cerevisiae that is expressed in vacuole membranes. In the present system, proteoliposome studies of purified FUN26 demonstrate robust nucleoside and nucleobase uptake into the luminal volume for a broad range of substrates. This transport activity is sensitive to nucleoside modifications in the C(2')- and C(5')-positions on the ribose sugar and is not stimulated by a membrane pH differential. [(3)H]Adenine nucleobase transport efficiency is increased ∼4-fold relative to nucleosides tested with no observed [(3)H]adenosine or [(3)H]UTP transport. FUN26 mutational studies identified residues that disrupt (G463A or G216A) or modulate (F249I or L390A) transporter function. These results demonstrate that FUN26 has a unique substrate transport profile relative to known ENT family members and that a purified ENT can be reconstituted in proteoliposomes for functional characterization in a defined system.
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Affiliation(s)
| | | | - Kelli D Duggan
- From the Department of Biochemistry and Molecular Biology and
| | - Zygy Roe-Žurž
- the Department of Biochemistry and Biophysics, University of California, San Francisco, California 94143
| | - Hannah Schmitz
- From the Department of Biochemistry and Molecular Biology and
| | - Carter Burleson
- From the Department of Biochemistry and Molecular Biology and
| | - Franklin A Hays
- From the Department of Biochemistry and Molecular Biology and the Stephenson Oklahoma Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104 and
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Kato M, Lin SJ. YCL047C/POF1 is a novel nicotinamide mononucleotide adenylyltransferase (NMNAT) in Saccharomyces cerevisiae. J Biol Chem 2014; 289:15577-87. [PMID: 24759102 DOI: 10.1074/jbc.m114.558643] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
NAD(+) is an essential metabolic cofactor involved in various cellular biochemical processes. Nicotinamide riboside (NR) is an endogenously produced key pyridine metabolite that plays important roles in the maintenance of NAD(+) pool. Using a NR-specific cell-based screen, we identified mutants that exhibit altered NR release phenotype. Yeast cells lacking the ORF YCL047C/POF1 release considerably more NR compared with wild type, suggesting that POF1 plays an important role in NR/NAD(+) metabolism. The amino acid sequence of Pof1 indicates that it is a putative nicotinamide mononucleotide adenylyltransferase (NMNAT). Unlike other yeast NMNATs, Pof1 exhibits NMN-specific adenylyltransferase activity. Deletion of POF1 significantly lowers NAD(+) levels and decreases the efficiency of NR utilization, resistance to oxidative stress, and NR-induced life span extension. We also show that NR is constantly produced by multiple nucleotidases and that the intracellular NR pools are likely to be compartmentalized, which contributes to the regulation of NAD(+) homeostasis. Our findings may contribute to the understanding of the molecular basis and regulation of NAD(+) metabolism in higher eukaryotes.
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Affiliation(s)
- Michiko Kato
- From the Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, California 95616
| | - Su-Ju Lin
- From the Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, California 95616
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36
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Wierman MB, Smith JS. Yeast sirtuins and the regulation of aging. FEMS Yeast Res 2014; 14:73-88. [PMID: 24164855 PMCID: PMC4365911 DOI: 10.1111/1567-1364.12115] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 10/09/2013] [Accepted: 10/13/2013] [Indexed: 11/29/2022] Open
Abstract
The sirtuins are a phylogenetically conserved family of NAD(+) -dependent protein deacetylases that consume one molecule of NAD(+) for every deacetylated lysine side chain. Their requirement for NAD(+) potentially makes them prone to regulation by fluctuations in NAD(+) or biosynthesis intermediates, thus linking them to cellular metabolism. The Sir2 protein from Saccharomyces cerevisiae is the founding sirtuin family member and has been well characterized as a histone deacetylase that functions in transcriptional silencing of heterochromatin domains and as a pro-longevity factor for replicative life span (RLS), defined as the number of times a mother cell divides (buds) before senescing. Deleting SIR2 shortens RLS, while increased gene dosage causes extension. Furthermore, Sir2 has been implicated in mediating the beneficial effects of caloric restriction (CR) on life span, not only in yeast, but also in higher eukaryotes. While this paradigm has had its share of disagreements and debate, it has also helped rapidly drive the aging research field forward. S. cerevisiae has four additional sirtuins, Hst1, Hst2, Hst3, and Hst4. This review discusses the function of Sir2 and the Hst homologs in replicative aging and chronological aging, and also addresses how the sirtuins are regulated in response to environmental stresses such as CR.
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Affiliation(s)
- Margaret B Wierman
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA, USA
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37
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Nucleotides and Nucleosides: Transport, Metabolism, and Signaling Function of Extracellular ATP. PROGRESS IN BOTANY 2014. [DOI: 10.1007/978-3-642-38797-5_4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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38
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Chi Y, Sauve AA. Nicotinamide riboside, a trace nutrient in foods, is a vitamin B3 with effects on energy metabolism and neuroprotection. Curr Opin Clin Nutr Metab Care 2013; 16:657-61. [PMID: 24071780 DOI: 10.1097/mco.0b013e32836510c0] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE OF REVIEW This review focuses upon the biology and metabolism of a trace component in foods called nicotinamide riboside. Nicotinamide riboside is a precursor of nicotinamide adenine dinucleotide (NAD), and is a source of Vitamin B3. Evidence indicates that nicotinamide riboside has unique properties as a Vitamin B3. We review knowledge of the metabolism of this substance, as well as recent work suggesting novel health benefits that might be associated with nicotinamide riboside taken in larger quantities than is found naturally in foods. RECENT FINDINGS Recent work investigating the effects of nicotinamide riboside in yeast and mammals established that it is metabolized by at least two types of metabolic pathways. The first of these is degradative and produces nicotinamide. The second pathway involves kinases called nicotinamide riboside kinases (Nrk1 and Nrk2, in humans). The likely involvement of the kinase pathway is implicated in the unique effects of nicotinamide riboside in raising tissue NAD concentrations in rodents and for potent effects in eliciting insulin sensitivity, mitochondrial biogenesis, and enhancement of sirtuin functions. Additional studies with nicotinamide riboside in models of Alzheimer's disease indicate bioavailability to brain and protective effects, likely by stimulation of brain NAD synthesis. SUMMARY Initial studies have clarified the potential for a lesser-known Vitamin B3 called nicotinamide riboside that is available in selected foods, and possibly available to humans by supplements. It has properties that are insulin sensitizing, enhancing to exercise, resisting to negative effects of high-fat diet, and neuroprotecting.
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Affiliation(s)
- Yuling Chi
- aDepartment of Medicine, Albert Einstein College of Medicine, Bronx bDepartment of Pharmacology, Weill Cornell Medical College, New York, New York, USA
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Trammell SA, Brenner C. Targeted, LCMS-based Metabolomics for Quantitative Measurement of NAD(+) Metabolites. Comput Struct Biotechnol J 2013; 4:e201301012. [PMID: 24688693 PMCID: PMC3962138 DOI: 10.5936/csbj.201301012] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 05/09/2013] [Accepted: 05/09/2013] [Indexed: 01/07/2023] Open
Abstract
Nicotinamide adenine dinucleotide (NAD+) is a coenzyme for hydride transfer reactions and a substrate for sirtuins and other NAD+-consuming enzymes. The abundance of NAD +, NAD+ biosynthetic intermediates, and related nucleotides reflects the metabolic state of cells and tissues. High performance liquid chromatography (HPLC) followed by ultraviolet-visible (UV-Vis) spectroscopic analysis of NAD+ metabolites does not offer the specificity and sensitivity necessary for robust quantification of complex samples. Thus, we developed a targeted, quantitative assay of the NAD+ metabolome with the use of HPLC coupled to mass spectrometry. Here we discuss NAD+ metabolism as well as the technical challenges required for reliable quantification of the NAD+ metabolites. The new method incorporates new separations and improves upon a previously published method that suffered from the problem of ionization suppression for particular compounds.
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Affiliation(s)
- Samuel Aj Trammell
- Department of Biochemistry ; Interdisciplinary Graduate Program in Genetics Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Charles Brenner
- Department of Biochemistry ; Interdisciplinary Graduate Program in Genetics Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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Cankorur-Cetinkaya A, Eraslan S, Kirdar B. Transcriptional remodelling in response to changing copper levels in the Wilson and Menkes disease model of Saccharomyces cerevisiae. MOLECULAR BIOSYSTEMS 2013; 9:2889-908. [DOI: 10.1039/c3mb70276f] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Stein LR, Imai SI. The dynamic regulation of NAD metabolism in mitochondria. Trends Endocrinol Metab 2012; 23:420-8. [PMID: 22819213 PMCID: PMC3683958 DOI: 10.1016/j.tem.2012.06.005] [Citation(s) in RCA: 378] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 06/17/2012] [Accepted: 06/19/2012] [Indexed: 11/22/2022]
Abstract
Mitochondria are intracellular powerhouses that produce ATP and carry out diverse functions for cellular energy metabolism. Although the maintenance of an optimal NAD/NADH ratio is essential for mitochondrial function, it has recently become apparent that the maintenance of the mitochondrial NAD pool is also of crucial importance. The biosynthesis, transport, and catabolism of NAD and its key intermediates play an important role in the regulation of NAD-consuming mediators, such as sirtuins, poly-ADP-ribose polymerases, and CD38/157 ectoenzymes, in intra- and extracellular compartments. Mitochondrial NAD biosynthesis is also modulated in response to nutritional and environmental stimuli. In this article, we discuss this dynamic regulation of NAD metabolism in mitochondria to shed light on the intimate connection between NAD and mitochondrial function.
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Affiliation(s)
- Liana Roberts Stein
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
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Sliwa D, Dairou J, Camadro JM, Santos R. Inactivation of mitochondrial aspartate aminotransferase contributes to the respiratory deficit of yeast frataxin-deficient cells. Biochem J 2012; 441:945-53. [PMID: 22010850 DOI: 10.1042/bj20111574] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Friedreich's ataxia is a hereditary neurodegenerative disease caused by reduced expression of mitochondrial frataxin. Frataxin deficiency causes impairment in respiratory capacity, disruption of iron homoeostasis and hypersensitivity to oxidants. Although the redox properties of NAD (NAD+ and NADH) are essential for energy metabolism, only few results are available concerning homoeostasis of these nucleotides in frataxin-deficient cells. In the present study, we show that the malate-aspartate NADH shuttle is impaired in Saccharomyces cerevisiae frataxin-deficient cells (Δyfh1) due to decreased activity of cytosolic and mitochondrial isoforms of malate dehydrogenase and to complete inactivation of the mitochondrial aspartate aminotransferase (Aat1). A considerable decrease in the amount of mitochondrial acetylated proteins was observed in the Δyfh1 mutant compared with wild-type. Aat1 is acetylated in wild-type mitochondria and deacetylated in Δyfh1 mitochondria suggesting that inactivation could be due to this post-translational modification. Mutants deficient in iron-sulfur cluster assembly or lacking mitochondrial DNA also showed decreased activity of Aat1, suggesting that Aat1 inactivation was a secondary phenotype in Δyfh1 cells. Interestingly, deletion of the AAT1 gene in a wild-type strain caused respiratory deficiency and disruption of iron homoeostasis without any sensitivity to oxidative stress. Our results show that secondary inactivation of Aat1 contributes to the amplification of the respiratory defect observed in Δyfh1 cells. Further implication of mitochondrial protein deacetylation in the physiology of frataxin-deficient cells is anticipated.
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Affiliation(s)
- Dominika Sliwa
- Institut Jacques Monod, CNRS-Université Paris Diderot, Sorbonne Paris Cité, 15 rue Hélène Brion, 75205 Paris cedex 13, France
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Kazemi Seresht A, Palmqvist EA, Olsson L. The impact of phosphate scarcity on pharmaceutical protein production in S. cerevisiae: linking transcriptomic insights to phenotypic responses. Microb Cell Fact 2011; 10:104. [PMID: 22151908 PMCID: PMC3265430 DOI: 10.1186/1475-2859-10-104] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Accepted: 12/07/2011] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND The adaptation of unicellular organisms like Saccharomyces cerevisiae to alternating nutrient availability is of great fundamental and applied interest, as understanding how eukaryotic cells respond to variations in their nutrient supply has implications spanning from physiological insights to biotechnological applications. RESULTS The impact of a step-wise restricted supply of phosphate on the physiological state of S. cerevisiae cells producing human Insulin was studied. The focus was to determine the changes within the global gene expression of cells being cultured to an industrially relevant high cell density of 33 g/l cell dry weight and under six distinct phosphate concentrations, ranging from 33 mM (unlimited) to 2.6 mM (limited). An increased flux through the secretory pathway, being induced by the PHO circuit during low P(i) supplementation, proved to enhance the secretory production of the heterologous protein. The re-distribution of the carbon flux from biomass formation towards increased glycerol production under low phosphate led to increased transcript levels of the insulin gene, which was under the regulation of the TPI1 promoter. CONCLUSIONS Our study underlines the dynamic character of adaptive responses of cells towards a change in their nutrient access. The gradual decrease of the phosphate supply resulted in a step-wise modulated phenotypic response, thereby alternating the specific productivity and the secretory flux. Our work emphasizes the importance of reduced phosphate supply for improved secretory production of heterologous proteins.
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Affiliation(s)
- Ali Kazemi Seresht
- Protein Expression, Novo Nordisk A/S, Novo Nordisk Park 1, 2760-Måløv, Denmark
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Valluru R, Van den Ende W. Myo-inositol and beyond--emerging networks under stress. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2011; 181:387-400. [PMID: 21889044 DOI: 10.1016/j.plantsci.2011.07.009] [Citation(s) in RCA: 203] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Revised: 07/18/2011] [Accepted: 07/19/2011] [Indexed: 05/18/2023]
Abstract
Myo-inositol is a versatile compound that generates diversified derivatives upon phosphorylation by lipid-dependent and -independent pathways. Phosphatidylinositols form one such group of myo-inositol derivatives that act both as membrane structural lipid molecules and as signals. The significance of these compounds lies in their dual functions as signals as well as key metabolites under stress. Several stress- and non-stress related pathways regulated by phosphatidylinositol isoforms and associated enzymes, kinases and phosphatases, appear to function in parallel to coordinatively adapt growth and stress responses in plants. Recent evidence also postulates their crucial roles in nuclear functions as they interact with the key players of chromatin structure, yet other nuclear functions remain largely unknown. Phosphatidylinositol monophosphate 5-kinase interacts with and represses a cytosolic neutral invertase, a key enzyme of sugar metabolism suggesting a crosstalk between lipid and sugar signaling. Besides phosphatidylinositol, myo-inositol derived galactinol and associated raffinose-family oligosaccharides are emerging as antioxidants and putative signaling compounds too. Importantly, myo-inositol polyphosphate 5-phosphatase (5PTase) acts, depending on sugar status, as a positive or negative regulator of a global energy sensor, SnRK1. This implies that both myo-inositol- and sugar-derived (e.g. trehalose 6-phosphate) molecules form part of a broad regulatory network with SnRK1 as the central regulator. Recently, it was shown that the transcription factor bZIP11 also takes part in this network. Moreover, a functional coordination between neutral invertase and hexokinase is emerging as a sweet network that contributes to oxidative stress homeostasis in plants. In this review, we focus on myo-inositol, its direct and more downstream derivatives (galactinol, raffinose), and the contribution of their associated networks to plant stress tolerance.
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Affiliation(s)
- Ravi Valluru
- Ecophysiology of Plants Under Environmental Stress, INRA-SUPAGRO, Institute of Integrative Plant Biology, 2 Place Viala, Montpellier, France
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Brenner C. On the nonspecific degradation of NAD+ to nicotinamide riboside. J Biol Chem 2011; 286:le5; author reply Ie6. [PMID: 21572049 DOI: 10.1074/jbc.l110.217885] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Lu SP, Lin SJ. Response to Brenner: Growth Stage-dependent Regulation of Nicotinamide Riboside (NmR) Production. J Biol Chem 2011. [DOI: 10.1074/jbc.n110.217885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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