701
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Ramsey KM, Mills KF, Satoh A, Imai SI. Age-associated loss of Sirt1-mediated enhancement of glucose-stimulated insulin secretion in beta cell-specific Sirt1-overexpressing (BESTO) mice. Aging Cell 2008; 7:78-88. [PMID: 18005249 DOI: 10.1111/j.1474-9726.2007.00355.x] [Citation(s) in RCA: 238] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The Sir2 (silent information regulator 2) family of NAD-dependent deacetylases regulates aging and longevity across a wide variety of organisms, including yeast, worms, and flies. In mammals, the Sir2 ortholog Sirt1 promotes fat mobilization, fatty acid oxidation, glucose production, and insulin secretion in response to nutrient availability. We previously reported that an increased dosage of Sirt1 in pancreatic beta cells enhances glucose-stimulated insulin secretion (GSIS) and improves glucose tolerance in beta cell-specific Sirt1-overexpressing (BESTO) transgenic mice at 3 and 8 months of age. Here, we report that as this same cohort of BESTO mice reaches 18-24 months of age, the GSIS regulated by Sirt1 through repression of Ucp2 is blunted. Increased body weight and hyperlipidemia alone, which are observed in aged males and also induced by a Western-style high-fat diet, are not enough to abolish the positive effects of Sirt1 on beta cell function. Interestingly, plasma levels of nicotinamide mononucleotide (NMN), an important metabolite for the maintenance of normal NAD biosynthesis and GSIS in beta cells, are significantly reduced in aged BESTO mice. Furthermore, NMN administration restores enhanced GSIS and improved glucose tolerance in the aged BESTO females, suggesting that Sirt1 activity decreases with advanced age due to a decline in systemic NAD biosynthesis. These findings provide insight into the age-dependent regulation of Sirt1 activity and suggest that enhancement of systemic NAD biosynthesis and Sirt1 activity in tissues such as beta cells may be an effective therapeutic intervention for age-associated metabolic disorders such as type 2 diabetes.
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Affiliation(s)
- Kathryn Moynihan Ramsey
- Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St Louis, MO 63110, USA
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702
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Abstract
The role of NAD(+) metabolism in health and disease is of increased interest as the use of niacin (nicotinic acid) has emerged as a major therapy for treatment of hyperlipidemias and with the recognition that nicotinamide can protect tissues and NAD(+) metabolism in a variety of disease states, including ischemia/reperfusion. In addition, a growing body of evidence supports the view that NAD(+) metabolism regulates important biological effects, including lifespan. NAD(+) exerts potent effects through the poly(ADP-ribose) polymerases, mono-ADP-ribosyltransferases, and the recently characterized sirtuin enzymes. These enzymes catalyze protein modifications, such as ADP-ribosylation and deacetylation, leading to changes in protein function. These enzymes regulate apoptosis, DNA repair, stress resistance, metabolism, and endocrine signaling, suggesting that these enzymes and/or NAD(+) metabolism could be targeted for therapeutic benefit. This review considers current knowledge of NAD(+) metabolism in humans and microbes, including new insights into mechanisms that regulate NAD(+) biosynthetic pathways, current use of nicotinamide and nicotinic acid as pharmacological agents, and opportunities for drug design that are directed at modulation of NAD(+) biosynthesis for treatment of human disorders and infections.
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Affiliation(s)
- Anthony A Sauve
- Department of Pharmacology, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10021, USA.
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703
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Abstract
The Sir2 (silent information regulator 2) family of nicotinamide adenine dinucleotide-dependent deacetylases has been implicated in the regulation of aging and longevity across a wide variety of organisms. Although controversial, Sir2 proteins have also been implicated as key mediators for the beneficial effects of caloric restriction (CR) on aging and longevity. In this issue, Bordone et al. report that transgenic mice in which the mammalian Sir2 ortholog Sirt1 is overexpressed mimic the physiological changes in response to CR. These findings have important implications for the development of CR mimetics and perhaps also for lifespan extension.
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Affiliation(s)
- Shin-ichiro Imai
- Department of Molecular Biology and Pharmacology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA.
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704
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Khan JA, Xiang S, Tong L. Crystal structure of human nicotinamide riboside kinase. Structure 2007; 15:1005-13. [PMID: 17698003 DOI: 10.1016/j.str.2007.06.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2007] [Revised: 06/13/2007] [Accepted: 06/27/2007] [Indexed: 01/12/2023]
Abstract
Nicotinamide riboside kinase (NRK) has an important role in the biosynthesis of NAD(+) as well as the activation of tiazofurin and other NR analogs for anticancer therapy. NRK belongs to the deoxynucleoside kinase and nucleoside monophosphate (NMP) kinase superfamily, although the degree of sequence conservation is very low. We report here the crystal structures of human NRK1 in a binary complex with the reaction product nicotinamide mononucleotide (NMN) at 1.5 A resolution and in a ternary complex with ADP and tiazofurin at 2.7 A resolution. The active site is located in a groove between the central parallel beta sheet core and the LID and NMP-binding domains. The hydroxyl groups on the ribose of NR are recognized by Asp56 and Arg129, and Asp36 is the general base of the enzyme. Mutation of residues in the active site can abolish the catalytic activity of the enzyme, confirming the structural observations.
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Affiliation(s)
- Javed A Khan
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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705
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Revollo JR, Körner A, Mills KF, Satoh A, Wang T, Garten A, Dasgupta B, Sasaki Y, Wolberger C, Townsend RR, Milbrandt J, Kiess W, Imai SI. Nampt/PBEF/Visfatin regulates insulin secretion in beta cells as a systemic NAD biosynthetic enzyme. Cell Metab 2007; 6:363-75. [PMID: 17983582 PMCID: PMC2098698 DOI: 10.1016/j.cmet.2007.09.003] [Citation(s) in RCA: 679] [Impact Index Per Article: 39.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2007] [Revised: 07/31/2007] [Accepted: 09/12/2007] [Indexed: 01/30/2023]
Abstract
Intracellular nicotinamide phosphoribosyltransferase (iNampt) is an essential enzyme in the NAD biosynthetic pathway. An extracellular form of this protein (eNampt) has been reported to act as a cytokine named PBEF or an insulin-mimetic hormone named visfatin, but its physiological relevance remains controversial. Here we show that eNampt does not exert insulin-mimetic effects in vitro or in vivo but rather exhibits robust NAD biosynthetic activity. Haplodeficiency and chemical inhibition of Nampt cause defects in NAD biosynthesis and glucose-stimulated insulin secretion in pancreatic islets in vivo and in vitro. These defects are corrected by administration of nicotinamide mononucleotide (NMN), a product of the Nampt reaction. A high concentration of NMN is present in mouse plasma, and plasma eNampt and NMN levels are reduced in Nampt heterozygous females. Our results demonstrate that Nampt-mediated systemic NAD biosynthesis is critical for beta cell function, suggesting a vital framework for the regulation of glucose homeostasis.
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Affiliation(s)
- Javier R Revollo
- Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, MO 63110, USA
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706
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Medvedik O, Lamming DW, Kim KD, Sinclair DA. MSN2 and MSN4 link calorie restriction and TOR to sirtuin-mediated lifespan extension in Saccharomyces cerevisiae. PLoS Biol 2007; 5:e261. [PMID: 17914901 PMCID: PMC1994990 DOI: 10.1371/journal.pbio.0050261] [Citation(s) in RCA: 237] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2006] [Accepted: 08/06/2006] [Indexed: 11/19/2022] Open
Abstract
Calorie restriction (CR) robustly extends the lifespan of numerous species. In the yeast Saccharomyces cerevisiae, CR has been proposed to extend lifespan by boosting the activity of sirtuin deacetylases, thereby suppressing the formation of toxic repetitive ribosomal DNA (rDNA) circles. An alternative theory is that CR works by suppressing the TOR (target of rapamycin) signaling pathway, which extends lifespan via mechanisms that are unknown but thought to be independent of sirtuins. Here we show that TOR inhibition extends lifespan by the same mechanism as CR: by increasing Sir2p activity and stabilizing the rDNA locus. Further, we show that rDNA stabilization and lifespan extension by both CR and TOR signaling is due to the relocalization of the transcription factors Msn2p and Msn4p from the cytoplasm to the nucleus, where they increase expression of the nicotinamidase gene PNC1. These findings suggest that TOR and sirtuins may be part of the same longevity pathway in higher organisms, and that they may promote genomic stability during aging.
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Affiliation(s)
- Oliver Medvedik
- Paul F. Glenn Laboratories for the Biological Mechanisms of Aging, Department of Pathology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Dudley W Lamming
- Paul F. Glenn Laboratories for the Biological Mechanisms of Aging, Department of Pathology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Keyman D Kim
- Paul F. Glenn Laboratories for the Biological Mechanisms of Aging, Department of Pathology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - David A Sinclair
- Paul F. Glenn Laboratories for the Biological Mechanisms of Aging, Department of Pathology, Harvard Medical School, Boston, Massachusetts, United States of America
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707
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Matsui A, Yin Y, Yamanaka K, Iwasaki M, Ashihara H. Metabolic fate of nicotinamide in higher plants. PHYSIOLOGIA PLANTARUM 2007; 131:191-200. [PMID: 18251891 DOI: 10.1111/j.1399-3054.2007.00959.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Metabolism of [carbonyl-14C]nicotinamide was surveyed in various plant materials including the model plants, Arabidopsis thaliana, Oryza sativa and Lotus japonicus. In all plants studied, nicotinamide was used for the pyridine (nicotinamide adenine) nucleotide synthesis, probably after conversion to nicotinic acid. Radioactivity from [carbonyl-14C]nicotinamide was incorporated into trigonelline (1-N-methylnicotinic acid) and/or into nicotinic acid 1N-glucoside (Na-Glc). Trigonelline is formed mainly in leaves and cell cultures of O. sativa and L. japonicus and in seedlings of Trifolium incarnatum, Medicago sativa and Raphanus sativus. Trigonelline synthesis from nicotinamide is generally greater in leaves than in roots. Na-Glc was formed as the major nicotinic acid conjugate in A. thaliana and in tobacco Bright Yellow-2 cells. In seedlings of Chrysanthemum coronarium and Theobroma cacao, both trigonelline and Na-Glc were synthesized from [carbonyl-14C]nicotinamide. Trigonelline is accumulated in some seeds, mainly Leguminosae species. The pattern of formation of the nicotinic acid conjugates differs between species and organs.
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Affiliation(s)
- Ayu Matsui
- Department of Biological Sciences, Graduate School of Humanities and Sciences, Ochanomizu University, Bunkyo-ku, Tokyo 112-8610, Japan
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708
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Saunders LR, Verdin E. Sirtuins: critical regulators at the crossroads between cancer and aging. Oncogene 2007; 26:5489-504. [PMID: 17694089 DOI: 10.1038/sj.onc.1210616] [Citation(s) in RCA: 454] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Sirtuins (SIRTs 1-7), or class III histone deacetylases (HDACs), are protein deacetylases/ADP ribosyltransferases that target a wide range of cellular proteins in the nucleus, cytoplasm, and mitochondria for post-translational modification by acetylation (SIRT1, -2, -3 and -5) or ADP ribosylation (SIRT4 and -6). The orthologs of sirtuins in lower organisms play a critical role in regulating lifespan. As cancer is a disease of aging, we discuss the growing implications of the sirtuins in protecting against cancer development. Sirtuins regulate the cellular responses to stress and ensure that damaged DNA is not propagated and that mutations do not accumulate. SIRT1 also promotes replicative senescence under conditions of chronic stress. By participating in the stress response to genomic insults, sirtuins are thought to protect against cancer, but they are also emerging as direct participants in the growth of some cancers. Here, we review the growing implications of sirtuins both in cancer prevention and as specific and novel cancer therapeutic targets.
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Affiliation(s)
- L R Saunders
- Gladstone Institute of Virology and Immunology, University of California, San Francisco, CA, USA
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709
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Yang H, Yang T, Baur JA, Perez E, Matsui T, Carmona JJ, Lamming DW, Souza-Pinto NC, Bohr VA, Rosenzweig A, de Cabo R, Sauve AA, Sinclair DA. Nutrient-sensitive mitochondrial NAD+ levels dictate cell survival. Cell 2007; 130:1095-107. [PMID: 17889652 PMCID: PMC3366687 DOI: 10.1016/j.cell.2007.07.035] [Citation(s) in RCA: 770] [Impact Index Per Article: 45.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Revised: 02/06/2007] [Accepted: 07/20/2007] [Indexed: 12/17/2022]
Abstract
A major cause of cell death caused by genotoxic stress is thought to be due to the depletion of NAD(+) from the nucleus and the cytoplasm. Here we show that NAD(+) levels in mitochondria remain at physiological levels following genotoxic stress and can maintain cell viability even when nuclear and cytoplasmic pools of NAD(+) are depleted. Rodents fasted for 48 hr show increased levels of the NAD(+) biosynthetic enzyme Nampt and a concomitant increase in mitochondrial NAD(+). Increased Nampt provides protection against cell death and requires an intact mitochondrial NAD(+) salvage pathway as well as the mitochondrial NAD(+)-dependent deacetylases SIRT3 and SIRT4. We discuss the relevance of these findings to understanding how nutrition modulates physiology and to the evolution of apoptosis.
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Affiliation(s)
- Hongying Yang
- Department of Pathology, Paul F. Glenn Laboratories, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA, 02115, USA
| | - Tianle Yang
- Department of Pharmacology, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10021, USA
| | - Joseph A. Baur
- Department of Pathology, Paul F. Glenn Laboratories, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA, 02115, USA
| | - Evelyn Perez
- Laboratory of Experimental Gerontology, National Institute on Aging, Institutes of Health, 5600 Nathan Shock Drive, Baltimore, MD, 21224, USA
| | - Takashi Matsui
- Cardiovascular Division, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Juan J. Carmona
- Department of Pathology, Paul F. Glenn Laboratories, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA, 02115, USA
| | - Dudley W. Lamming
- Department of Pathology, Paul F. Glenn Laboratories, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA, 02115, USA
| | - Nadja C. Souza-Pinto
- Laboratory of Molecular Gerontology, National Institute on Aging, Institutes of Health, 5600 Nathan Shock Drive, Baltimore, MD, 21224, USA
| | - Vilhelm A. Bohr
- Laboratory of Molecular Gerontology, National Institute on Aging, Institutes of Health, 5600 Nathan Shock Drive, Baltimore, MD, 21224, USA
| | - Anthony Rosenzweig
- Cardiovascular Division, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Rafael de Cabo
- Laboratory of Experimental Gerontology, National Institute on Aging, Institutes of Health, 5600 Nathan Shock Drive, Baltimore, MD, 21224, USA
| | - Anthony A. Sauve
- Department of Pharmacology, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10021, USA
| | - David A. Sinclair
- Department of Pathology, Paul F. Glenn Laboratories, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA, 02115, USA
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710
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Abstract
A major cause of cell death caused by genotoxic stress is thought to be due to the depletion of NAD(+) from the nucleus and the cytoplasm. Here we show that NAD(+) levels in mitochondria remain at physiological levels following genotoxic stress and can maintain cell viability even when nuclear and cytoplasmic pools of NAD(+) are depleted. Rodents fasted for 48 hr show increased levels of the NAD(+) biosynthetic enzyme Nampt and a concomitant increase in mitochondrial NAD(+). Increased Nampt provides protection against cell death and requires an intact mitochondrial NAD(+) salvage pathway as well as the mitochondrial NAD(+)-dependent deacetylases SIRT3 and SIRT4. We discuss the relevance of these findings to understanding how nutrition modulates physiology and to the evolution of apoptosis.
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711
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Abstract
Sirtuins or Sir2 (silent information regulator 2)-related enzymes have originally been defined as a family of nicotinamide adenine dinucleotide-dependent enzymes that deacetylate lysine residue on various proteins. Certain sirtuins have in addition an ADP-ribosyltransferase activity. The sirtuins are remarkably conserved throughout evolution from archaebacteria to eukaryotes. The mammalian sirtuins SIRT1-SIRT7 are implicated in a variety of cellular functions ranging from gene silencing, over the control of the cell cycle and apoptosis, to energy homeostasis. On a whole-body level, the wide range of cellular activities of the sirtuins suggests that they could constitute therapeutic targets to combat metabolic, neurodegenerative, and proliferative diseases. Here, we review some of the recent data related to the sirtuins and discuss their mode of action, their biological role in cellular and organismal models, and their possible association to age-related human diseases.
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Affiliation(s)
- Hiroyasu Yamamoto
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 1 Rue Laurent Fries, Boite Postale 10142, 67404 Illkirch, France
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712
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Tanaka M, Nozaki M, Fukuhara A, Segawa K, Aoki N, Matsuda M, Komuro R, Shimomura I. Visfatin is released from 3T3-L1 adipocytes via a non-classical pathway. Biochem Biophys Res Commun 2007; 359:194-201. [PMID: 17543285 DOI: 10.1016/j.bbrc.2007.05.096] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Accepted: 05/06/2007] [Indexed: 10/23/2022]
Abstract
Visfatin is a secretory protein which exerts insulin mimetic and proinflammatory effects, also functioning as an intracellular enzyme to produce NAD. Plasma visfatin levels and visfatin mRNA expression in adipose tissues are increased in obese subjects. Visfatin does not have a decent cleavable signal sequence, and the mechanism, that mediates release of visfatin from adipocytes, remains poorly understood. In this study, we demonstrate that visfatin is released abundantly into culture medium from 3T3-L1 adipocytes. Subcellular fractionation analysis showed that visfatin was localized in the cytosol, but not in nucleus, membrane, vesicles, or mitochondria fractions. Visfatin release was not reduced by Brefeldin A and Monensin, inhibitors of endoplasmic reticulum (ER)-Golgi-dependent secretion. In addition, visfatin was not released on microvesicles. These results suggest that visfatin should be released from 3T3-L1 adipocytes via an ER-Golgi or microvesicles independent pathway.
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Affiliation(s)
- Masaki Tanaka
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka, Japan
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713
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Abstract
In addition to hyperglycemia, diabetes is associated with increased levels of circulating free fatty acids, lactate, and branched chain amino acids, all of which produce an excessive reduced form of pyridine nucleotides NADH (reductive stress) in the cytosol and mitochondria. Our studies suggest that cytosolic NADH reductive stress under high glucose is largely caused by increased flux of glucose through polyol (sorbitol) pathway consisting of aldose reductase and sorbitol dehydrogenase. Inhibition of aldose reductase that blocks the polyol pathway has been shown to ameliorate diabetic neuropathy in humans. Cytosolic NADH reductive stress is predicted to increase production of diglycerides, reactive oxygen species, and methylglyoxal. Recent studies indicate that increasing NADH affects gene expression through the NADH activating transcriptional co-repressor, C-terminal binding protein (CtBP). In addition, it has been shown that the NADH utilizing enzyme, glyceraldehyde-3-phosphate dehydrogenase, participates as transcriptional regulator. These findings testify to the importance of NADH redox balance in cell biology and pathogenesis of diabetes and its complications. For example, through CtBP, the high NADH to NAD(+) ratio decreases an expression of SirT1, the protein inducing longevity and anti-apoptosis. This review covers metabolic cascades causing reductive stress and oxidative stress in diabetes after a brief introduction of the redox concept.
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Affiliation(s)
- Yasuo Ido
- Boston University Medical Center, Boston, MA 02118, USA.
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714
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Hara N, Yamada K, Shibata T, Osago H, Hashimoto T, Tsuchiya M. Elevation of cellular NAD levels by nicotinic acid and involvement of nicotinic acid phosphoribosyltransferase in human cells. J Biol Chem 2007; 282:24574-82. [PMID: 17604275 DOI: 10.1074/jbc.m610357200] [Citation(s) in RCA: 150] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
NAD plays critical roles in various biological processes through the function of SIRT1. Although classical studies in mammals showed that nicotinic acid (NA) is a better precursor than nicotinamide (Nam) in elevating tissue NAD levels, molecular details of NAD synthesis from NA remain largely unknown. We here identified NA phosphoribosyltransferase (NAPRT) in humans and provided direct evidence of tight link between NAPRT and the increase in cellular NAD levels. The enzyme was abundantly expressed in the small intestine, liver, and kidney in mice and mediated [(14)C]NAD synthesis from [(14)C]NA in human cells. In cells expressing endogenous NAPRT, the addition of NA but not Nam almost doubled cellular NAD contents and decreased cytotoxicity by H(2)O(2). Both effects were reversed by knockdown of NAPRT expression. These results indicate that NAPRT is essential for NA to increase cellular NAD levels and, thus, to prevent oxidative stress of the cells. Kinetic analyses revealed that NAPRT, but not Nam phosphoribosyltransferase (NamPRT, also known as pre-B-cell colony-enhancing factor or visfatin), is insensitive to the physiological concentration of NAD. Together, we conclude that NA elevates cellular NAD levels through NAPRT function and, thus, protects the cells against stress, partly due to lack of feedback inhibition of NAPRT but not NamPRT by NAD. The ability of NA to increase cellular NAD contents may account for some of the clinically observed effects of the vitamin and further implies a novel application of the vitamin to treat diseases such as those associated with the depletion of cellular NAD pools.
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Affiliation(s)
- Nobumasa Hara
- Department of Biochemistry, Shimane University Faculty of Medicine, 89-1, Izumo, Shimane 693-8501, Japan.
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715
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Belenky P, Racette FG, Bogan KL, McClure JM, Smith JS, Brenner C. Nicotinamide riboside promotes Sir2 silencing and extends lifespan via Nrk and Urh1/Pnp1/Meu1 pathways to NAD+. Cell 2007; 129:473-84. [PMID: 17482543 DOI: 10.1016/j.cell.2007.03.024] [Citation(s) in RCA: 308] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2006] [Revised: 02/07/2007] [Accepted: 03/16/2007] [Indexed: 10/23/2022]
Abstract
Although NAD(+) biosynthesis is required for Sir2 functions and replicative lifespan in yeast, alterations in NAD(+) precursors have been reported to accelerate aging but not to extend lifespan. In eukaryotes, nicotinamide riboside is a newly discovered NAD(+) precursor that is converted to nicotinamide mononucleotide by specific nicotinamide riboside kinases, Nrk1 and Nrk2. In this study, we discovered that exogenous nicotinamide riboside promotes Sir2-dependent repression of recombination, improves gene silencing, and extends lifespan without calorie restriction. The mechanism of action of nicotinamide riboside is totally dependent on increased net NAD(+) synthesis through two pathways, the Nrk1 pathway and the Urh1/Pnp1/Meu1 pathway, which is Nrk1 independent. Additionally, the two nicotinamide riboside salvage pathways contribute to NAD(+) metabolism in the absence of nicotinamide-riboside supplementation. Thus, like calorie restriction in the mouse, nicotinamide riboside elevates NAD(+) and increases Sir2 function.
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Affiliation(s)
- Peter Belenky
- Departments of Genetics and Biochemistry and the Norris Cotton Cancer Center, Dartmouth Medical School, Rubin 733-HB7937, Lebanon, NH 03756, USA
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716
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Khan JA, Forouhar F, Tao X, Tong L. Nicotinamide adenine dinucleotide metabolism as an attractive target for drug discovery. Expert Opin Ther Targets 2007; 11:695-705. [PMID: 17465726 DOI: 10.1517/14728222.11.5.695] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Nicotinamide adenine dinucleotide (NAD(+)) has crucial roles in many cellular processes, both as a coenzyme for redox reactions and as a substrate to donate ADP-ribose units. Enzymes involved in NAD(+) metabolism are attractive targets for drug discovery against a variety of human diseases, including cancer, multiple sclerosis, neurodegeneration and Huntington's disease. A small-molecule inhibitor of nicotinamide phosphoribosyltransferase, an enzyme in the salvage pathway of NAD(+) biosynthesis, is presently in clinical trials against cancer. An analog of a kynurenine pathway intermediate is efficacious against multiple sclerosis in an animal model. Indoleamine 2,3-dioxygenase plays an important role in immune evasion by cancer cells and other disease processes. Inhibitors against kynurenine 3-hydroxylase can reduce the production of neurotoxic metabolites while increasing the production of neuroprotective compounds. This review summarizes the existing knowledge on NAD(+) metabolic enzymes, with emphasis on their relevance for drug discovery.
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Affiliation(s)
- Javed A Khan
- Columbia University, Department of Biological Sciences, New York, NY 10027, USA
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717
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Dai Y, Ngo D, Forman LW, Qin DC, Jacob J, Faller DV. Sirtuin 1 is required for antagonist-induced transcriptional repression of androgen-responsive genes by the androgen receptor. Mol Endocrinol 2007; 21:1807-21. [PMID: 17505061 PMCID: PMC3839341 DOI: 10.1210/me.2006-0467] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Androgen antagonists or androgen deprivation is a primary therapeutic modality for the treatment of prostate cancer. Invariably, however, the disease becomes progressive and unresponsive to androgen ablation therapy (hormone refractory). The molecular mechanisms by which the androgen antagonists inhibit prostate cancer proliferation are not fully defined. In this report, we demonstrate that sirtuin 1 (SIRT1), a nicotinamide adenosine dinucleotide-dependent histone deacetylase (HDAC) linked to the regulation of longevity, is required for androgen antagonist-mediated transcriptional repression and growth suppression. Androgen antagonist-bound androgen receptor (AR) recruits SIRT1 and nuclear receptor corepressor to AR-responsive promoters and deacetylates histone H3 locally at the prostate-specific antigen promoter. Furthermore, SIRT1 down-regulation by small interfering RNA or by pharmacological means increased the sensitivity of androgen-responsive genes to androgen stimulation, enhanced the sensitivity of prostate cancer cell proliferative responses to androgens, and decreased the sensitivity of prostate cancer cells to androgen antagonists. In this study, we demonstrate the ligand-dependent recruitment of a class III HDAC into a corepressor transcriptional complex and a necessary functional role for a class III HDAC as a transcriptional corepressor in AR antagonist-induced transcriptional repression. Collectively, these findings identify SIRT1 as a corepressor of AR and elucidate a new molecular pathway relevant to prostate cancer growth and approaches to therapy.
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Affiliation(s)
- Yan Dai
- Address correspondence to: Yan Dai: Cancer Research Center Boston University School of Medicine, Boston, MA 02118 Tel: (617)638-5650. Fax: (617)638-5609. . Douglas V. Faller: K701, Cancer Center Boston University School of Medicine, Boston, MA 02118 Phone: (617)638-4173. FAX (617)638-4176.
| | | | | | | | | | - Douglas V. Faller
- Address correspondence to: Yan Dai: Cancer Research Center Boston University School of Medicine, Boston, MA 02118 Tel: (617)638-5650. Fax: (617)638-5609. . Douglas V. Faller: K701, Cancer Center Boston University School of Medicine, Boston, MA 02118 Phone: (617)638-4173. FAX (617)638-4176.
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718
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Wang P, van Greevenbroek MMJ, Bouwman FG, Brouwers MCGJ, van der Kallen CJH, Smit E, Keijer J, Mariman ECM. The circulating PBEF/NAMPT/visfatin level is associated with a beneficial blood lipid profile. Pflugers Arch 2007; 454:971-6. [PMID: 17429683 DOI: 10.1007/s00424-007-0262-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2006] [Revised: 02/09/2007] [Accepted: 03/22/2007] [Indexed: 10/23/2022]
Abstract
Visfatin with the official gene name pre-B cell colony-enhancing factor 1 (PBEF) and the protein name nicotinamide phosphoribosyltransferase (NAMPT) is a recently discovered adipocyte-secreted protein that was shown by some to be associated with visceral fat and insulin resistance. To explore the link between PBEF/NAMPT/visfatin and lipid metabolism, we analyzed the relation of its plasma level with several parameters of adiposity, insulin resistance and the circulating blood lipid profile in a group of general population (n = 40) and a group of subjects who are genetically predisposed to insulin resistance and hyperlipidemia (n = 35). In both groups and pooled cohort, PBEF/NAMPT/visfatin lacked association with whole body adiposity, but correlated positively with HDL-cholesterol and negatively with triglycerides. The data suggested a negative correlation of the PBEF level with visceral fat and insulin resistance. But this negative correlation completely disappeared after adjustment for lipid profile. We concluded that circulating PBEF/NAMPT/visfatin level is an indicator of beneficial lipid profile in non-diabetic Caucasian subjects. The relation to lipid metabolism does not depend on visceral obesity and insulin resistance, but may be linked to its enzymatic function in NAD metabolism.
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Affiliation(s)
- Ping Wang
- Department of Human Biology, Nutrition and Toxicology Research Institute Maastricht, Maastricht University, P.O. Box 616, 6200 MD, Maastricht, The Netherlands
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719
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Revollo JR, Grimm AA, Imai SI. The regulation of nicotinamide adenine dinucleotide biosynthesis by Nampt/PBEF/visfatin in mammals. Curr Opin Gastroenterol 2007; 23:164-70. [PMID: 17268245 DOI: 10.1097/mog.0b013e32801b3c8f] [Citation(s) in RCA: 206] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
PURPOSE OF REVIEW Nicotinamide adenine dinucleotide (NAD) is a classic coenzyme in cellular redox reactions. Recently, NAD biochemistry has also been implicated in a broader range of biological functions in mammals, but the regulation of NAD biosynthesis has been poorly investigated. Recent progress in the field of NAD biochemistry has fueled new interest in the NAD biosynthetic pathways from its precursors and their physiological roles in metabolism. This review summarizes the latest knowledge on the NAD biosynthetic pathways and focuses on one of the key NAD biosynthetic enzymes, namely, nicotinamide phosphoribosyltransferase. RECENT FINDINGS Mammals predominantly use nicotinamide rather than nicotinic acid as a precursor for NAD biosynthesis. Nicotinamide phosphoribosyltransferase (Nampt) is the rate-limiting enzyme that converts nicotinamide to nicotinamide mononucleotide in the NAD biosynthetic pathway from nicotinamide in mammals. The same protein has also been identified as a cytokine (pre-B-cell colony-enhancing factor or PBEF) or an insulin-mimetic hormone (visfatin). SUMMARY We propose that the presumed multiple effects of Nampt/PBEF/visfatin may be entirely explained by its role as an intra and extracellular NAD biosynthetic enzyme. We also propose a new model of Namp/PBEF/visfatin-mediated systemic NAD biosynthesis and its possible physiological significance. Our model provides an important insight into developing preventive/therapeutic interventions for metabolic complications, such as obesity and diabetes.
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Affiliation(s)
- Javier R Revollo
- Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St Louis, Missouri 63110, USA
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720
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Wang G, Pichersky E. Nicotinamidase participates in the salvage pathway of NAD biosynthesis in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2007; 49:1020-9. [PMID: 17335512 DOI: 10.1111/j.1365-313x.2006.03013.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP), which is derived from NAD, have important roles as a redox carriers in metabolism. A combination of de novo and salvage pathways contribute to the biosynthesis of NAD in all organisms. The pathways and enzymes of the NAD salvage pathway in yeast and animals, which diverge at nicotinamide, have been extensively studied. Yeast cells convert nicotinamide to nicotinic acid, while mammals lack the enzyme nicotinamidase and instead convert nicotinamide to nicotinamide mononucleotide. Here we show that Arabidopsis thaliana gene At2g22570 encodes a nicotinamidase, which is expressed in all tissues, with the highest levels observed in roots and stems. The 244-residue protein, designated AtNIC1, converts nicotinamide to nicotinic acid and has a Km value of 118 +/- 17 microM and a Kcat value of 0.93 +/- 0.13 sec(-1). Plants homozygous for a null AtNIC1 allele, nic1-1, have lower levels of NAD and NADP under normal growth conditions, indicating that AtNIC1 participates in a yeast-type NAD salvage pathway. Mutant plants also exhibit hypersensitivity to treatments of abscisic acid and NaCl, which is correlated with their inability to increase the cellular levels of NAD(H) under these growth conditions, as occurs in wild-type plants. We also show that the growth of the roots of wild-type but not nic1-1 mutant plants is inhibited and distorted by nicotinamide.
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Affiliation(s)
- Guodong Wang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, 830 North University Street, Ann Arbor, MI 48109-1048, USA
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721
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van der Veer E, Ho C, O'Neil C, Barbosa N, Scott R, Cregan SP, Pickering JG. Extension of human cell lifespan by nicotinamide phosphoribosyltransferase. J Biol Chem 2007; 282:10841-5. [PMID: 17307730 DOI: 10.1074/jbc.c700018200] [Citation(s) in RCA: 242] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Extending the productive lifespan of human cells could have major implications for diseases of aging, such as atherosclerosis. We identified a relationship between aging of human vascular smooth muscle cells (SMCs) and nicotinamide phosphoribosyltransferase (Nampt/PBEF/Visfatin), the rate-limiting enzyme for NAD+ salvage from nicotinamide. Replicative senescence of SMCs was preceded by a marked decline in the expression and activity of Nampt. Furthermore, reducing Nampt activity with the antagonist FK866 induced premature senescence in SMCs, assessed by serial quantification of the proportion of cells with senescence-associated beta-galactosidase activity. In contrast, introducing the Nampt gene into aging human SMCs delayed senescence and substantially lengthened cell lifespan, together with enhanced resistance to oxidative stress. Nampt-mediated SMC lifespan extension was associated with increased activity of the NAD+-dependent longevity enzyme SIRT1 and was abrogated in Nampt-overexpressing cells transduced with a dominant-negative form of SIRT1 (H363Y). Nampt overexpression also reduced the fraction of p53 that was acetylated on lysine 382, a target of SIRT1, suppressed an age-related increase in p53 expression, and increased the rate of p53 degradation. Moreover, add-back of p53 with recombinant adenovirus blocked the anti-aging effects of Nampt. These data indicate that Nampt is a longevity protein that can add stress-resistant life to human SMCs by optimizing SIRT1-mediated p53 degradation.
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Affiliation(s)
- Eric van der Veer
- Robarts Research Institute and London Health Sciences Centre, Department of Medicine (Cardiology), University of Western Ontario, London, Ontario Canada N6A 5K8
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722
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Abstract
Sirtuins are a family of NAD+-dependent protein deacetylases widely distributed in all phyla of life. Accumulating evidence indicates that sirtuins are important regulators of organism life span. In yeast, these unique enzymes regulate gene silencing by histone deacetylation and via formation of the novel compound 2'-O-acetyl-ADP-ribose. In multicellular organisms, sirtuins deacetylate histones and transcription factors that regulate stress, metabolism, and survival pathways. The chemical mechanism of sirtuins provides novel opportunities for signaling and metabolic regulation of protein deacetylation. The biological, chemical, and structural characteristics of these unusual enzymes are discussed in this review.
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Affiliation(s)
- Anthony A Sauve
- Department of Pharmacology, Weill Medical College of Cornell University, New York, New York 10021, USA.
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723
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van der Horst A, Schavemaker JM, Pellis-van Berkel W, Burgering BMT. The Caenorhabditis elegans nicotinamidase PNC-1 enhances survival. Mech Ageing Dev 2007; 128:346-9. [PMID: 17335870 DOI: 10.1016/j.mad.2007.01.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2006] [Revised: 01/15/2007] [Accepted: 01/19/2007] [Indexed: 10/23/2022]
Abstract
In yeast, increasing the copy number of the nicotinamide adenine dinucleotide (NAD)-dependent deacetylase Sir2 extends lifespan, which can be inhibited by nicotinamide (Nam), the end-product of Sir2-mediated NAD-breakdown. Furthermore, the yeast pyrazinamidase/nicotinamidase PNC-1 can extend yeast lifespan by converting Nam. In Caenorhabditis elegans (C. elegans), increased dosage of the gene encoding SIR-2.1 also increases lifespan. Here, we report that knockdown of the C. elegans homologue of yeast PNC-1 as well as growing worms on Nam-containing medium significantly decreases adult lifespan. Accordingly, increased gene dosage of pnc-1 increases adult survival under conditions of oxidative stress. These data show for the first time the involvement of PNC-1/Nam in the survival of a multicellular organism and may also contribute to our understanding of lifespan regulation in mammals.
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Affiliation(s)
- Armando van der Horst
- Department of Physiological Chemistry, Centre for Biomedical Genetics, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands.
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724
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Dali-Youcef N, Lagouge M, Froelich S, Koehl C, Schoonjans K, Auwerx J. Sirtuins: the 'magnificent seven', function, metabolism and longevity. Ann Med 2007; 39:335-45. [PMID: 17701476 DOI: 10.1080/07853890701408194] [Citation(s) in RCA: 302] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
The sirtuin family of histone deacetylases (HDACs) was named after their homology to the Saccharomyces cerevisiae gene silent information regulator 2 (Sir2). In the yeast, Sir2 has been shown to mediate the effects of calorie restriction on the extension of life span and high levels of Sir2 activity promote longevity. Like their yeast homologs, the mammalian sirtuins (SIRT1-7) are class III HDACs and require NAD(+) as a cofactor to deacetylate substrates ranging from histones to transcriptional regulators. Through this activity, sirtuins are shown to regulate important biological processes ranging from apoptosis, adipocyte and muscle differentiation, and energy expenditure to gluconeogenesis. We review here the current knowledge regarding the role of sirtuins in metabolism, longevity, and discuss the possible therapeutic applications that could result from the understanding of their function in different organs and pathologies.
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Affiliation(s)
- Nassim Dali-Youcef
- Institut de Génétique et de Biologie Moléculaire et Cellulaire de Strasbourg (IGBMC), INSERM/CNRS/ULP, Illkirch, France
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725
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Belenky P, Bogan KL, Brenner C. NAD+ metabolism in health and disease. Trends Biochem Sci 2006; 32:12-9. [PMID: 17161604 DOI: 10.1016/j.tibs.2006.11.006] [Citation(s) in RCA: 692] [Impact Index Per Article: 38.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2006] [Revised: 11/01/2006] [Accepted: 11/23/2006] [Indexed: 01/12/2023]
Abstract
Nicotinamide adenine dinucleotide (NAD(+)) is both a coenzyme for hydride-transfer enzymes and a substrate for NAD(+)-consuming enzymes, which include ADP-ribose transferases, poly(ADP-ribose) polymerases, cADP-ribose synthases and sirtuins. Recent results establish protective roles for NAD(+) that might be applicable therapeutically to prevent neurodegenerative conditions and to fight Candida glabrata infection. In addition, the contribution that NAD(+) metabolism makes to lifespan extension in model systems indicates that therapies to boost NAD(+) might promote some of the beneficial effects of calorie restriction. Nicotinamide riboside, the recently discovered nucleoside precursor of NAD(+) in eukaryotic systems, might have advantages as a therapy to elevate NAD(+) without inhibiting sirtuins, which is associated with high-dose nicotinamide, or incurring the unpleasant side-effects of high-dose nicotinic acid.
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Affiliation(s)
- Peter Belenky
- Departments of Genetics and of Biochemistry and Norris Cotton Cancer Center, Dartmouth Medical School, Lebanon, NH 03756, USA
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726
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Yonezawa T, Haga S, Kobayashi Y, Takahashi T, Obara Y. Visfatin is present in bovine mammary epithelial cells, lactating mammary gland and milk, and its expression is regulated by cAMP pathway. FEBS Lett 2006; 580:6635-43. [PMID: 17123517 DOI: 10.1016/j.febslet.2006.11.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Revised: 11/02/2006] [Accepted: 11/03/2006] [Indexed: 11/21/2022]
Abstract
Visfatin was originally identified as a growth factor for immature B cells, and recently demonstrated to bind insulin receptor. Visfatin mRNA and protein were detected by RT-PCR and Western blot analysis in cloned bovine mammary epithelial cells, lactating bovine mammary gland and human breast cancer cell line, MCF-7. Immunocytochemical staining localized the visfatin protein in the cytosol and nucleus of both cells. Quantitative-RT-PCR analysis revealed that the expression of the visfatin mRNA was significantly elevated when treated with forskolin (500 microM), isopreterenol (1-10 microM) and dibutyric cyclic AMP (1 mM) for 24 h, and significantly reduced when treated with insulin (5-50 ng/ml) and dexsamethasone (0.5-250 nM) for 24 h. These results indicate that mammary epithelial cells express the visfatin protein and secrete them into the milk.
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Affiliation(s)
- Tomo Yonezawa
- Department of Animal Physiology, Graduate School of Agricultural Science, Tohoku University, Amamiyamachi, Sendai 981-8555, Japan.
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727
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Yang T, Sauve AA. NAD metabolism and sirtuins: metabolic regulation of protein deacetylation in stress and toxicity. AAPS JOURNAL 2006; 8:E632-43. [PMID: 17233528 PMCID: PMC2751359 DOI: 10.1208/aapsj080472] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Sirtuins are recently discovered NAD(+)-dependent deacetylases that remove acetyl groups from acetyllysine-modified proteins, thereby regulating the biological function of their targets. Sirtuins have been shown to increase organism and tissue survival in diverse organisms, ranging from yeast to mammals. Evidence indicates that NAD(+) metabolism and sirtuins contribute to mechanisms that influence cell survival under conditions of stress and toxicity. For example, recent work has shown that sirtuins and increased NAD(+) biosynthesis provide protection against neuron axonal degeneration initiated by genotoxicity or trauma. In light of their protective effects, sirtuins and NAD(+) metabolism could represent therapeutic targets for treatment of acute and chronic neurodegenerative conditions. Our work has focused on elucidating the enzymatic functions of sirtuins and quantifying perturbations of cellular NAD(+) metabolism. We have developed mass spectrometry methods to quantitate cellular NAD(+) and nicotinamide. These methods allow the quantitation of changes in the amounts of these metabolites in cells caused by chemical and genetic interventions. Characterization of the biochemical properties of sirtuins and investigations of NAD(+) metabolism are likely to provide new insights into mechanisms by which NAD(+) metabolism regulates sirtuin activities in cells. To develop new strategies to improve cell stress resistance, we have initiated proof of concept studies on pharmacological approaches that target sirtuins and NAD(+) metabolism, with the goal of enhancing cell protection against genotoxicity.
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Affiliation(s)
- Tianle Yang
- Department of Pharmacology, Weill Medical College of Cornell University, 1300 York Avenue, 10021 New York, NY
| | - Anthony A. Sauve
- Department of Pharmacology, Weill Medical College of Cornell University, 1300 York Avenue, 10021 New York, NY
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728
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Nowell MA, Richards PJ, Fielding CA, Ognjanovic S, Topley N, Williams AS, Bryant-Greenwood G, Jones SA. Regulation of pre-B cell colony-enhancing factor by STAT-3-dependent interleukin-6 trans-signaling: implications in the pathogenesis of rheumatoid arthritis. ACTA ACUST UNITED AC 2006; 54:2084-95. [PMID: 16802343 DOI: 10.1002/art.21942] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
OBJECTIVE To determine whether interleukin-6 (IL-6) trans-signaling directs the expression of pre-B cell colony-enhancing factor (PBEF) in vitro and in vivo. METHODS Complementary DNA from rheumatoid arthritis (RA) synovial fibroblasts treated with IL-6 and soluble IL-6 receptor (sIL-6R) was used to probe a cytokine microarray. PBEF regulation by the IL-6-related cytokines, IL-6, sIL-6R, oncostatin M (OSM), IL-11, and leukemia inhibitory factor (LIF) was determined by reverse transcription-polymerase chain reaction analysis. IL-6-mediated STAT-3 regulation of PBEF was determined using a cell-permeable STAT-3 inhibitor peptide. Antigen-induced arthritis (AIA) was induced in wild-type (IL-6(+/+)) and IL-6-deficient (IL-6(-/-)) mice. PBEF and STAT were detected by immunohistochemistry, immunoblotting, and electrophoretic mobility shift assay. Synovial levels of PBEF were quantified by enzyme immunoassay. RESULTS IL-6 trans-signaling regulated PBEF in a STAT-3-dependent manner. In addition, PBEF was regulated by the IL-6-related cytokine OSM, but not IL-11 or LIF. Flow cytometric analysis of the IL-6-related cognate receptors suggested that OSM regulates PBEF via its OSM receptor beta and not its LIF receptor. The involvement of PBEF in arthritis progression was confirmed in vivo, where induction of AIA resulted in a 4-fold increase in the synovial expression of PBEF. In contrast, little or no change was observed in IL-6(-/-) mice, in which the inflammatory infiltrate was markedly reduced and synovial STAT-1/3 activity was also impaired. Analysis of human RA synovial tissue confirmed that PBEF immunolocalized in apical synovial membrane cells, endothelial cells, adipocytes, and lymphoid aggregates. Synovial fluid levels of PBEF were significantly higher in RA patients than in osteoarthritis patients. CONCLUSION Experiments presented herein demonstrate that PBEF is regulated via IL-6 trans-signaling and the IL-6-related cytokine OSM. PBEF is also actively expressed during arthritis. Although these data confirm an involvement of PBEF in disease progression, the consequence of its action remains to be determined.
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Affiliation(s)
- Mari A Nowell
- Medical Biochemistry and Immunology, Tenovus Building, School of Medicine, Heath Park Campus, Cardiff University, Cardiff CF14 4XN, UK.
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729
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Sasaki Y, Araki T, Milbrandt J. Stimulation of nicotinamide adenine dinucleotide biosynthetic pathways delays axonal degeneration after axotomy. J Neurosci 2006; 26:8484-91. [PMID: 16914673 PMCID: PMC6674352 DOI: 10.1523/jneurosci.2320-06.2006] [Citation(s) in RCA: 212] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Axonal degeneration occurs in many neurodegenerative diseases and after traumatic injury and is a self-destructive program independent from programmed cell death. Previous studies demonstrated that overexpression of nicotinamide mononucleotide adenylyltransferase 1 (Nmnat1) or exogenous application of nicotinamide adenine dinucleotide (NAD) can protect axons of cultured dorsal root ganglion (DRG) neurons from degeneration caused by mechanical or neurotoxic injury. In mammalian cells, NAD can be synthesized from multiple precursors, including tryptophan, nicotinic acid, nicotinamide, and nicotinamide riboside (NmR), via multiple enzymatic steps. To determine whether other components of these NAD biosynthetic pathways are capable of delaying axonal degeneration, we overexpressed each of the enzymes involved in each pathway and/or exogenously administered their respective substrates in DRG cultures and assessed their capacity to protect axons after axotomy. Among the enzymes tested, Nmnat1 had the strongest protective effects, whereas nicotinamide phosphoribosyl transferase and nicotinic acid phosphoribosyl transferase showed moderate protective activity in the presence of their substrates. Strong axonal protection was also provided by Nmnat3, which is predominantly located in mitochondria, and an Nmnat1 mutant localized to the cytoplasm, indicating that the subcellular location of NAD production is not crucial for protective activity. In addition, we showed that exogenous application of the NAD precursors that are the substrates of these enzymes, including nicotinic acid mononucleotide, nicotinamide mononucleotide, and NmR, can also delay axonal degeneration. These results indicate that stimulation of NAD biosynthetic pathways via a variety of interventions may be useful in preventing or delaying axonal degeneration.
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730
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Fu M, Liu M, Sauve AA, Jiao X, Zhang X, Wu X, Powell MJ, Yang T, Gu W, Avantaggiati ML, Pattabiraman N, Pestell TG, Wang F, Quong AA, Wang C, Pestell RG. Hormonal control of androgen receptor function through SIRT1. Mol Cell Biol 2006; 26:8122-35. [PMID: 16923962 PMCID: PMC1636736 DOI: 10.1128/mcb.00289-06] [Citation(s) in RCA: 186] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The NAD-dependent histone deacetylase Sir2 plays a key role in connecting cellular metabolism with gene silencing and aging. The androgen receptor (AR) is a ligand-regulated modular nuclear receptor governing prostate cancer cellular proliferation, differentiation, and apoptosis in response to androgens, including dihydrotestosterone (DHT). Here, SIRT1 antagonists induce endogenous AR expression and enhance DHT-mediated AR expression. SIRT1 binds and deacetylates the AR at a conserved lysine motif. Human SIRT1 (hSIRT1) repression of DHT-induced AR signaling requires the NAD-dependent catalytic function of hSIRT1 and the AR lysine residues deacetylated by SIRT1. SIRT1 inhibited coactivator-induced interactions between the AR amino and carboxyl termini. DHT-induced prostate cancer cellular contact-independent growth is also blocked by SIRT1, providing a direct functional link between the AR, which is a critical determinant of progression of human prostate cancer, and the sirtuins.
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Affiliation(s)
- Maofu Fu
- Department of Cancer Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
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731
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Yang H, Lavu S, Sinclair DA. Nampt/PBEF/Visfatin: a regulator of mammalian health and longevity? Exp Gerontol 2006; 41:718-26. [PMID: 16842957 PMCID: PMC3366689 DOI: 10.1016/j.exger.2006.06.003] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2006] [Revised: 05/31/2006] [Accepted: 06/01/2006] [Indexed: 02/06/2023]
Abstract
Eukaryotes have evolved elaborate mechanisms to survive periods of adversity. By manipulating genes that control these mechanisms, researchers have found they can generate more stress resistant, longer-lived organisms. One of these is the PNC1 gene of Saccharomyces cerevisiae, a master "longevity regulatory gene" that translates a variety of environmental stresses into lifespan extension by activating the sirtuin family of longevity deacetylases. Master longevity genes such as PNC1 are highly adaptive because they allow organisms to respond in a concerted way to adversity and to rapidly evolve life strategies to compensate for a changing environment. Hence, they should be well conserved. We propose that there is a functional equivalent of PNC1 in mammals called Nampt (a.k.a. PBEF/Visfatin), a stress-responsive gene that would coordinately regulate metabolism, cell defenses, and resistance to diseases of aging.
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Affiliation(s)
| | | | - David A. Sinclair
- Corresponding author. Tel.: +1 617 432 3931; fax: +1 617 432 6225. (D.A. Sinclair)
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732
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Yang T, Fu M, Pestell R, Sauve AA. SIRT1 and endocrine signaling. Trends Endocrinol Metab 2006; 17:186-91. [PMID: 16684606 DOI: 10.1016/j.tem.2006.04.002] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Revised: 03/21/2006] [Accepted: 04/25/2006] [Indexed: 10/24/2022]
Abstract
Sirtuins (Sir2-related enzymes) are a recently discovered class of NAD(+)-dependent protein deacetylases that regulate gene expression in a variety of organisms by deacetylation of modified lysine residues on histones, transcription factors and other proteins. Conservation of sirtuin regulation of the insulin-insulin-like growth factor I signaling pathway has been observed for Caenorhabditis elegans and mammals, indicating an ancient role for sirtuins in the modulation of organism adaptations to nutritional intake. The human sirtuin SIRT1 regulates a number of transcription factors that modulate endocrine signaling, including peroxisome proliferator-activated receptor gamma, peroxisome proliferator-activated receptor gamma coactivator 1alpha, forkhead-box transcription factors and p53.
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Affiliation(s)
- Tianle Yang
- Department of Pharmacology, Weill Medical College of Cornell University, 1300 York Avenue, LC-216, New York, NY 10021, USA
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733
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Khan JA, Tao X, Tong L. Molecular basis for the inhibition of human NMPRTase, a novel target for anticancer agents. Nat Struct Mol Biol 2006; 13:582-8. [PMID: 16783377 DOI: 10.1038/nsmb1105] [Citation(s) in RCA: 199] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2006] [Accepted: 05/09/2006] [Indexed: 01/07/2023]
Abstract
Nicotinamide phosphoribosyltransferase (NMPRTase) has a crucial role in the salvage pathway of NAD+ biosynthesis, and a potent inhibitor of NMPRTase, FK866, can reduce cellular NAD+ levels and induce apoptosis in tumors. We have determined the crystal structures at up to 2.1-A resolution of human and murine NMPRTase, alone and in complex with the reaction product nicotinamide mononucleotide or the inhibitor FK866. The structures suggest that Asp219 is a determinant of substrate specificity of NMPRTase, which is confirmed by our mutagenesis studies. FK866 is bound in a tunnel at the interface of the NMPRTase dimer, and mutations in this binding site can abolish the inhibition by FK866. Contrary to current knowledge, the structures show that FK866 should compete directly with the nicotinamide substrate. Our structural and biochemical studies provide a starting point for the development of new anticancer agents.
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Affiliation(s)
- Javed A Khan
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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734
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Wang T, Zhang X, Bheda P, Revollo JR, Imai SI, Wolberger C. Structure of Nampt/PBEF/visfatin, a mammalian NAD+ biosynthetic enzyme. Nat Struct Mol Biol 2006; 13:661-2. [PMID: 16783373 DOI: 10.1038/nsmb1114] [Citation(s) in RCA: 204] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2006] [Accepted: 05/23/2006] [Indexed: 02/07/2023]
Abstract
Nicotinamide phosphoribosyltransferase (Nampt) synthesizes nicotinamide mononucleotide (NMN) from nicotinamide in a mammalian NAD+ biosynthetic pathway and is required for SirT1 activity in vivo. Nampt has also been presumed to be a cytokine (PBEF) or a hormone (visfatin). The crystal structure of Nampt in the presence and absence of NMN shows that Nampt is a dimeric type II phosphoribosyltransferase and provides insights into the enzymatic mechanism.
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Affiliation(s)
- Tao Wang
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, 725 N. Wolfe St., Baltimore, Maryland 21205, USA
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735
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Pillai JB, Gupta M, Rajamohan SB, Lang R, Raman J, Gupta MP. Poly(ADP-ribose) polymerase-1-deficient mice are protected from angiotensin II-induced cardiac hypertrophy. Am J Physiol Heart Circ Physiol 2006; 291:H1545-53. [PMID: 16632544 DOI: 10.1152/ajpheart.01124.2005] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Poly(ADP-ribose) polymerase-1 (PARP), a chromatin-bound enzyme, is activated by cell oxidative stress. Because oxidative stress is also considered a main component of angiotensin II-mediated cell signaling, it was postulated that PARP could be a downstream target of angiotensin II-induced signaling leading to cardiac hypertrophy. To determine a role of PARP in angiotensin II-induced hypertrophy, we infused angiotensin II into wild-type (PARP(+/+)) and PARP-deficient mice. Angiotensin II infusion significantly increased heart weight-to-tibia length ratio, myocyte cross-sectional area, and interstitial fibrosis in PARP(+/+) but not in PARP(-/-) mice. To confirm these results, we analyzed the effect of angiotensin II in primary cultures of cardiomyocytes. When compared with PARP(-/-) cardiomyocytes, angiotensin II (1 microM) treatment significantly increased protein synthesis in PARP(+/+) myocytes, as measured by (3)H-leucine incorporation into total cell protein. Angiotensin II-mediated hypertrophy of myocytes was accompanied with increased poly-ADP-ribosylation of nuclear proteins and depletion of cellular NAD content. When cells were treated with cell death-inducing doses of angiotensin II (10-20 microM), robust myocyte cell death was observed in PARP(+/+) but not in PARP(-/-) myocytes. This type of cell death was blocked by repletion of cellular NAD levels as well as by activation of the longevity factor Sir2alpha deacetylase, indicating that PARP induction and subsequent depletion of NAD levels are the sequence of events causing angiotensin II-mediated cardiomyocyte cell death. In conclusion, these results demonstrate that PARP is a nuclear integrator of angiotensin II-mediated cell signaling contributing to cardiac hypertrophy and suggest that this could be a novel therapeutic target for the management of heart failure.
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Affiliation(s)
- Jyothish B Pillai
- Dept. of Surgery, MC 5040, Univ. of Chicago, 5841 S. Maryland Ave., Chicago, IL 60637, USA
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736
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Gerdes SY, Kurnasov OV, Shatalin K, Polanuyer B, Sloutsky R, Vonstein V, Overbeek R, Osterman AL. Comparative genomics of NAD biosynthesis in cyanobacteria. J Bacteriol 2006; 188:3012-23. [PMID: 16585762 PMCID: PMC1446974 DOI: 10.1128/jb.188.8.3012-3023.2006] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2005] [Accepted: 01/23/2006] [Indexed: 11/20/2022] Open
Abstract
Biosynthesis of NAD(P) cofactors is of special importance for cyanobacteria due to their role in photosynthesis and respiration. Despite significant progress in understanding NAD(P) biosynthetic machinery in some model organisms, relatively little is known about its implementation in cyanobacteria. We addressed this problem by a combination of comparative genome analysis with verification experiments in the model system of Synechocystis sp. strain PCC 6803. A detailed reconstruction of the NAD(P) metabolic subsystem using the SEED genomic platform (http://theseed.uchicago.edu/FIG/index.cgi) helped us accurately annotate respective genes in the entire set of 13 cyanobacterial species with completely sequenced genomes available at the time. Comparative analysis of operational variants implemented in this divergent group allowed us to elucidate both conserved (de novo and universal pathways) and variable (recycling and salvage pathways) aspects of this subsystem. Focused genetic and biochemical experiments confirmed several conjectures about the key aspects of this subsystem. (i) The product of the slr1691 gene, a homolog of Escherichia coli gene nadE containing an additional nitrilase-like N-terminal domain, is a NAD synthetase capable of utilizing glutamine as an amide donor in vitro. (ii) The product of the sll1916 gene, a homolog of E. coli gene nadD, is a nicotinic acid mononucleotide-preferring adenylyltransferase. This gene is essential for survival and cannot be compensated for by an alternative nicotinamide mononucleotide (NMN)-preferring adenylyltransferase (slr0787 gene). (iii) The product of the slr0788 gene is a nicotinamide-preferring phosphoribosyltransferase involved in the first step of the two-step non-deamidating utilization of nicotinamide (NMN shunt). (iv) The physiological role of this pathway encoded by a conserved gene cluster, slr0787-slr0788, is likely in the recycling of endogenously generated nicotinamide, as supported by the inability of this organism to utilize exogenously provided niacin. Positional clustering and the co-occurrence profile of the respective genes across a diverse collection of cellular organisms provide evidence of horizontal transfer events in the evolutionary history of this pathway.
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Affiliation(s)
- Svetlana Y. Gerdes
- Fellowship for Interpretation of Genomes, Burr Ridge, Illinois 60527, Burnham Institute for Medical Research, La Jolla, California 92037, Department of Biochemistry, New York University School of Medicine, New York, New York 10016, Rohm and Haas Company, Advanced Biosciences Division, Spring House, Pennsylvania 19477, Department of Molecular Virology, Immunology, and Medical Genetics, Ohio State University, Columbus, Ohio 43210
| | - Oleg V. Kurnasov
- Fellowship for Interpretation of Genomes, Burr Ridge, Illinois 60527, Burnham Institute for Medical Research, La Jolla, California 92037, Department of Biochemistry, New York University School of Medicine, New York, New York 10016, Rohm and Haas Company, Advanced Biosciences Division, Spring House, Pennsylvania 19477, Department of Molecular Virology, Immunology, and Medical Genetics, Ohio State University, Columbus, Ohio 43210
| | - Konstantin Shatalin
- Fellowship for Interpretation of Genomes, Burr Ridge, Illinois 60527, Burnham Institute for Medical Research, La Jolla, California 92037, Department of Biochemistry, New York University School of Medicine, New York, New York 10016, Rohm and Haas Company, Advanced Biosciences Division, Spring House, Pennsylvania 19477, Department of Molecular Virology, Immunology, and Medical Genetics, Ohio State University, Columbus, Ohio 43210
| | - Boris Polanuyer
- Fellowship for Interpretation of Genomes, Burr Ridge, Illinois 60527, Burnham Institute for Medical Research, La Jolla, California 92037, Department of Biochemistry, New York University School of Medicine, New York, New York 10016, Rohm and Haas Company, Advanced Biosciences Division, Spring House, Pennsylvania 19477, Department of Molecular Virology, Immunology, and Medical Genetics, Ohio State University, Columbus, Ohio 43210
| | - Roman Sloutsky
- Fellowship for Interpretation of Genomes, Burr Ridge, Illinois 60527, Burnham Institute for Medical Research, La Jolla, California 92037, Department of Biochemistry, New York University School of Medicine, New York, New York 10016, Rohm and Haas Company, Advanced Biosciences Division, Spring House, Pennsylvania 19477, Department of Molecular Virology, Immunology, and Medical Genetics, Ohio State University, Columbus, Ohio 43210
| | - Veronika Vonstein
- Fellowship for Interpretation of Genomes, Burr Ridge, Illinois 60527, Burnham Institute for Medical Research, La Jolla, California 92037, Department of Biochemistry, New York University School of Medicine, New York, New York 10016, Rohm and Haas Company, Advanced Biosciences Division, Spring House, Pennsylvania 19477, Department of Molecular Virology, Immunology, and Medical Genetics, Ohio State University, Columbus, Ohio 43210
| | - Ross Overbeek
- Fellowship for Interpretation of Genomes, Burr Ridge, Illinois 60527, Burnham Institute for Medical Research, La Jolla, California 92037, Department of Biochemistry, New York University School of Medicine, New York, New York 10016, Rohm and Haas Company, Advanced Biosciences Division, Spring House, Pennsylvania 19477, Department of Molecular Virology, Immunology, and Medical Genetics, Ohio State University, Columbus, Ohio 43210
| | - Andrei L. Osterman
- Fellowship for Interpretation of Genomes, Burr Ridge, Illinois 60527, Burnham Institute for Medical Research, La Jolla, California 92037, Department of Biochemistry, New York University School of Medicine, New York, New York 10016, Rohm and Haas Company, Advanced Biosciences Division, Spring House, Pennsylvania 19477, Department of Molecular Virology, Immunology, and Medical Genetics, Ohio State University, Columbus, Ohio 43210
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737
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Moynihan KA, Imai SI. Sirt1 as a key regulator orchestrating the response to caloric restriction. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.ddmec.2006.02.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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738
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Hackl H, Burkard TR, Sturn A, Rubio R, Schleiffer A, Tian S, Quackenbush J, Eisenhaber F, Trajanoski Z. Molecular processes during fat cell development revealed by gene expression profiling and functional annotation. Genome Biol 2005; 6:R108. [PMID: 16420668 PMCID: PMC1414107 DOI: 10.1186/gb-2005-6-13-r108] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2005] [Revised: 08/23/2005] [Accepted: 11/08/2005] [Indexed: 12/31/2022] Open
Abstract
In-depth bioinformatics analyses of expressed sequence tags found to be differentially expressed during differentiation of 3T3-L1 pre-adipocyte cells were combined with de novo functional annotation and mapping onto known pathways to generate a molecular atlas of fat-cell development. Background Large-scale transcription profiling of cell models and model organisms can identify novel molecular components involved in fat cell development. Detailed characterization of the sequences of identified gene products has not been done and global mechanisms have not been investigated. We evaluated the extent to which molecular processes can be revealed by expression profiling and functional annotation of genes that are differentially expressed during fat cell development. Results Mouse microarrays with more than 27,000 elements were developed, and transcriptional profiles of 3T3-L1 cells (pre-adipocyte cells) were monitored during differentiation. In total, 780 differentially expressed expressed sequence tags (ESTs) were subjected to in-depth bioinformatics analyses. The analysis of 3'-untranslated region sequences from 395 ESTs showed that 71% of the differentially expressed genes could be regulated by microRNAs. A molecular atlas of fat cell development was then constructed by de novo functional annotation on a sequence segment/domain-wise basis of 659 protein sequences, and subsequent mapping onto known pathways, possible cellular roles, and subcellular localizations. Key enzymes in 27 out of 36 investigated metabolic pathways were regulated at the transcriptional level, typically at the rate-limiting steps in these pathways. Also, coexpressed genes rarely shared consensus transcription-factor binding sites, and were typically not clustered in adjacent chromosomal regions, but were instead widely dispersed throughout the genome. Conclusions Large-scale transcription profiling in conjunction with sophisticated bioinformatics analyses can provide not only a list of novel players in a particular setting but also a global view on biological processes and molecular networks.
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Affiliation(s)
- Hubert Hackl
- Institute for Genomics and Bioinformatics and Christian Doppler Laboratory for Genomics and Bioinformatics, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
| | - Thomas Rainer Burkard
- Institute for Genomics and Bioinformatics and Christian Doppler Laboratory for Genomics and Bioinformatics, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
- Research Institute of Molecular Pathology, Dr Bohr-Gasse 7, 1030 Vienna, Austria
| | - Alexander Sturn
- Institute for Genomics and Bioinformatics and Christian Doppler Laboratory for Genomics and Bioinformatics, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
| | - Renee Rubio
- Dana-Farber Cancer Institute, Department of Biostatistics and Computational Biology, 44 Binney Street, Boston, MA 02115
| | - Alexander Schleiffer
- Research Institute of Molecular Pathology, Dr Bohr-Gasse 7, 1030 Vienna, Austria
| | - Sun Tian
- Research Institute of Molecular Pathology, Dr Bohr-Gasse 7, 1030 Vienna, Austria
| | - John Quackenbush
- Dana-Farber Cancer Institute, Department of Biostatistics and Computational Biology, 44 Binney Street, Boston, MA 02115
| | - Frank Eisenhaber
- Research Institute of Molecular Pathology, Dr Bohr-Gasse 7, 1030 Vienna, Austria
| | - Zlatko Trajanoski
- Institute for Genomics and Bioinformatics and Christian Doppler Laboratory for Genomics and Bioinformatics, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
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739
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Porcu M, Chiarugi A. The emerging therapeutic potential of sirtuin-interacting drugs: from cell death to lifespan extension. Trends Pharmacol Sci 2005; 26:94-103. [PMID: 15681027 DOI: 10.1016/j.tips.2004.12.009] [Citation(s) in RCA: 147] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Acetylation of chromatin-interacting proteins is central to the epigenetic regulation of genome architecture and gene expression. Chemicals that modulate the acetylation of nuclear proteins have proved instrumental in experimental models of several human diseases. Sirtuins represent a new class of evolutionary conserved histone deacetylases, originally identified in yeast, that have emerging pathogenetic roles in cancer, diabetes, muscle differentiation, heart failure, neurodegeneration and aging. In this article, we focus on sirtuins and provide an appraisal of current compounds that either activate or inhibit sirtuin activity, highlighting their therapeutic potential for the treatment of human diseases.
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Affiliation(s)
- Marco Porcu
- Department of Preclinical and Clinical Pharmacology, University of Florence, 50139 Florence, Italy
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740
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Chappie JS, Cànaves JM, Han GW, Rife CL, Xu Q, Stevens RC. The structure of a eukaryotic nicotinic acid phosphoribosyltransferase reveals structural heterogeneity among type II PRTases. Structure 2005; 13:1385-96. [PMID: 16154095 DOI: 10.1016/j.str.2005.05.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2005] [Revised: 05/18/2005] [Accepted: 05/18/2005] [Indexed: 11/16/2022]
Abstract
Nicotinamide adenine dinucleotide (NAD) is an essential cofactor for cellular redox reactions and can act as an important substrate in numerous biological processes. As a result, nature has evolved multiple biosynthetic pathways to meet this high chemical demand. In Saccharomyces cerevisiae, the NAD salvage pathway relies on the activity of nicotinic acid phosphoribosyltransferase (NAPRTase), a member of the phosphoribosyltransferase (PRTase) superfamily. Here, we report the structure of a eukaryotic (yeast) NAPRTase at 1.75 A resolution (locus name: YOR209C, gene name: NPT1). The structure reveals a two-domain fold that resembles the architecture of quinolinic acid phosphoribosyltransferases (QAPRTases), but with completely different dispositions that provide evidence for structural heterogeneity among the Type II PRTases. The identification of a third domain in NAPRTases provides a structural basis and possible mechanism for the functional modulation of this family of enzymes by ATP.
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Affiliation(s)
- Joshua S Chappie
- The Joint Center for Structural Genomics, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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741
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Ye SQ, Zhang LQ, Adyshev D, Usatyuk PV, Garcia AN, Lavoie TL, Verin AD, Natarajan V, Garcia JGN. Pre-B-cell-colony-enhancing factor is critically involved in thrombin-induced lung endothelial cell barrier dysregulation. Microvasc Res 2005; 70:142-51. [PMID: 16188281 DOI: 10.1016/j.mvr.2005.08.003] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2005] [Revised: 08/15/2005] [Accepted: 08/16/2005] [Indexed: 11/26/2022]
Abstract
Prior genomic and genetic studies identified pre-B-cell colony-enhancing factor (PBEF) as a novel candidate gene and biomarker in acute lung injury (ALI). As increased vascular permeability is a cardinal feature of ALI, we assessed the role of PBEF in in vitro vascular barrier regulation using confluent human pulmonary artery endothelial cell (HPAEC) monolayers. Reductions in PBEF protein expression (>70%) by siRNA significantly attenuated EC barrier dysfunction induced by the potent edemagenic agent, thrombin, reflected by reductions in transendothelial electric resistance (TER, approximately 60% reduction). Furthermore, PBEF siRNA blunted thrombin-mediated increases in Ca(2+) entry, polymerized actin formation, and myosin light chain phosphorylation, events critical to the thrombin-mediated permeability response. Finally, PBEF siRNA also significantly inhibited thrombin-stimulated increase of IL-8 secretion in HPAEC, a chemokine known to induce actin fiber formation and intercellular gap formation of endothelial cells. Taken together, these studies demonstrate that PBEF may be required for complete expression of the thrombin-induced inflammatory response and reveal potentially novel role for PBEF in the regulation of EC Ca(2+)-dependent cytoskeletal rearrangement and endothelial barrier dysfunction. Ongoing studies will continue to address the molecular mechanisms by which PBEF contributes to ALI susceptibility.
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Affiliation(s)
- Shui Q Ye
- Department of Medicine, Section of Pulmonary/Critical Care, University of Chicago Pritzker School of Medicine, 5841 S. Maryland Avenue, MC 6076, Chicago, IL 60637, USA.
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742
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Abstract
The Sir2 family of histone/protein deacetylases (sirtuins) is comprised of homologues found across all kingdoms of life. These enzymes catalyse a unique reaction in which NAD+ and acetylated substrate are converted into deacetylated product, nicotinamide, and a novel metabolite O-acetyl ADP-ribose. Although the catalytic mechanism is well conserved across Sir2 family members, sirtuins display differential specificity toward acetylated substrates, which translates into an expanding range of physiological functions. These roles include control of gene expression, cell cycle regulation, apoptosis, metabolism and ageing. The dependence of sirtuin activity on NAD+ has spearheaded investigations into how these enzymes respond to metabolic signals, such as caloric restriction. In addition, NAD+ metabolites and NAD+ salvage pathway enzymes regulate sirtuin activity, supporting a link between deacetylation of target proteins and metabolic pathways. Apart from physiological regulators, forward chemical genetics and high-throughput activity screening has been used to identify sirtuin inhibitors and activators. This review focuses on small molecule regulators that control the activity and functions of this unusual family of protein deacetylases.
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Affiliation(s)
- Olivera Grubisha
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, WI 53706-1532, USA
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743
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Sinclair DA. Toward a unified theory of caloric restriction and longevity regulation. Mech Ageing Dev 2005; 126:987-1002. [PMID: 15893363 DOI: 10.1016/j.mad.2005.03.019] [Citation(s) in RCA: 398] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2004] [Revised: 02/03/2005] [Accepted: 03/15/2005] [Indexed: 12/15/2022]
Abstract
The diet known as calorie restriction (CR) is the most reproducible way to extend the lifespan of mammals. Many of the early hypotheses to explain this effect were based on it being a passive alteration in metabolism. Yet, recent data from yeast, worms, flies, and mammals support the idea that CR is not simply a passive effect but an active, highly conserved stress response that evolved early in life's history to increase an organism's chance of surviving adversity. This perspective updates the evidence for and against the various hypotheses of CR, and concludes that many of them can be synthesized into a single, unifying hypothesis. This has important implications for how we might develop novel medicines that can harness these newly discovered innate mechanisms of disease resistance and survival.
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Affiliation(s)
- David A Sinclair
- Department of Pathology, Harvard Medical School, 77 Avenue Louis Paster, Boston, MA 02115, USA.
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744
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Kim MY, Zhang T, Kraus WL. Poly(ADP-ribosyl)ation by PARP-1: 'PAR-laying' NAD+ into a nuclear signal. Genes Dev 2005; 19:1951-67. [PMID: 16140981 DOI: 10.1101/gad.1331805] [Citation(s) in RCA: 639] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Poly(ADP-ribose) (PAR) and the PAR polymerases (PARPs) that catalyze its synthesis from donor nicotinamide adenine dinucleotide (NAD+) molecules have received considerable attention in the recent literature. Poly(ADP-ribosyl)ation (PARylation) plays diverse roles in many molecular and cellular processes, including DNA damage detection and repair, chromatin modification, transcription, cell death pathways, insulator function, and mitotic apparatus function. These processes are critical for many physiological and pathophysiological outcomes, including genome maintenance, carcinogenesis, aging, inflammation, and neuronal function. This review highlights recent work on the biochemistry, molecular biology, physiology, and pathophysiology of PARylation, focusing on the activity of PARP-1, the most abundantly expressed member of a family of PARP proteins. In addition, connections between nuclear NAD+ metabolism and nuclear signaling through PARP-1 are discussed.
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Affiliation(s)
- Mi Young Kim
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
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745
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Pillai JB, Isbatan A, Imai SI, Gupta MP. Poly(ADP-ribose) polymerase-1-dependent cardiac myocyte cell death during heart failure is mediated by NAD+ depletion and reduced Sir2alpha deacetylase activity. J Biol Chem 2005; 280:43121-30. [PMID: 16207712 DOI: 10.1074/jbc.m506162200] [Citation(s) in RCA: 318] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Robust activation of poly(ADP-ribose) polymerase-1 (PARP) by oxidative stress has been implicated as a major cause of caspase-independent myocyte cell death contributing to heart failure. Here, we show that depletion of myocyte NAD levels and the subsequent reduction of Sir2alpha deacetylase activity are the sequential steps contributing to PARP-mediated myocyte cell death. In both failing hearts and cultured cardiac myocytes, the increased activity of PARP was associated with depletion of cellular NAD levels and reduced Sir2alpha deacetylase activity. Myocyte cell death induced by PARP activation was prevented by repletion of cellular NAD levels either by adding NAD directly to the culture medium or by overexpressing NAD biosynthetic enzymes. The beneficial effect of NAD repletion was seen, however, only when Sir2alpha was intact. Knocking down Sir2alpha levels by small interfering RNA eliminated this benefit, indicating that Sir2alpha is a downstream target of NAD replenishment leading to cell protection. NAD repletion also prevented loss of the transcriptional regulatory activity of the Sir2alpha catalytic core domain resulting from PARP activation. We also show that PARP activation and the concomitant reduction of Sir2alpha activity in failing hearts regulate the post-translational acetylation of p53. These data demonstrate that, in stressed cardiac myocytes, depletion of cellular NAD levels forms a link between PARP activation and reduced Sir2alpha deacetylase activity, contributing to myocyte cell death during heart failure.
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Affiliation(s)
- Jyothish B Pillai
- Department of Cardiothoracic Surgery, University of Chicago, IL 60637, USA
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746
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Abstract
The importance of NAD(+)-dependent deacetylases (Sir 2 family or sirtuins) in cell survival, ageing and apoptosis has ignited a flurry of both chemical and cellular investigations aimed at understanding this unique class of enzymes. This review focuses on recent mechanistic advances that highlight structure, catalysis, substrate recognition and interactions with small-molecule effectors. Recent X-ray structures revealed binding sites for both NAD(+) and acetyl-peptide. Biochemical studies support a two-step chemical mechanism involving the initial formation of a 1'-O-alkylamidate adduct formed between the acetyl-group and the nicotinamide ribose of NAD(+). Acetyl transfer to the 2' ribose and addition of water yield deacetylated peptide and 2'-O-acetyl-ADP-ribose, a potential second messenger. Also, the molecular basis of nicotinamide inhibition was revealed, and sirtuin activators (resveratrol) and inhibitors (sirtinol and splitomicin) were identified through small-molecule library screening.
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Affiliation(s)
- John M Denu
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, WI 53706, USA.
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747
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van der Veer E, Nong Z, O'Neil C, Urquhart B, Freeman D, Pickering JG. Pre-B-cell colony-enhancing factor regulates NAD+-dependent protein deacetylase activity and promotes vascular smooth muscle cell maturation. Circ Res 2005; 97:25-34. [PMID: 15947248 DOI: 10.1161/01.res.0000173298.38808.27] [Citation(s) in RCA: 148] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Conversion of vascular smooth muscle cells (SMCs) from a proliferative state to a nonproliferative, contractile state confers vasomotor function to developing and remodeling blood vessels. Using a maturation-competent human SMC line, we determined that this shift in phenotype was accompanied by upregulation of pre-B-cell colony-enhancing factor (PBEF), a protein proposed to be a cytokine. Knockdown of endogenous PBEF increased SMC apoptosis and reduced the capacity of synthetic SMCs to mature to a contractile state. In keeping with these findings, human SMCs transduced with the PBEF gene had enhanced survival, an elongated bipolar morphology, and increased levels of h-caldesmon, smoothelin-A, smoothelin-B, and metavinculin. Notwithstanding some prior reports, PBEF did not have attributes of a cytokine but instead imparted the cell with increased nicotinamide phosphoribosyltransferase activity. Intracellular nicotinamide adenine dinucleotide (NAD+) content was increased in PBEF-overexpressing SMCs and decreased in PBEF-knockdown SMCs. Furthermore, NAD+-dependent protein deacetylase activity was found to be essential for SMC maturation and was increased by PBEF. Xenotransplantation of human SMCs into immunodeficient mice revealed an increased capacity for PBEF-overexpressing SMCs to mature and intimately invest nascent endothelial channels. This microvessel chimerism and maturation process was perturbed when SMC PBEF expression was lowered. These findings identify PBEF as a regulator of NAD+-dependent reactions in SMCs, reactions that promote, among other potential processes, the acquisition of a mature SMC phenotype.
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Affiliation(s)
- Eric van der Veer
- Robarts Research Institute (Vascular Biology Group), Department of Medicine (Cardiology), University of Western Ontario, London, Canada
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748
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Zheng XQ, Hayashibe E, Ashihara H. Changes in trigonelline (N-methylnicotinic acid) content and nicotinic acid metabolism during germination of mungbean (Phaseolus aureus) seeds. JOURNAL OF EXPERIMENTAL BOTANY 2005; 56:1615-1623. [PMID: 15837705 DOI: 10.1093/jxb/eri156] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Changes in trigonelline content and in biosynthetic activity were determined in the cotyledons and embryonic axes of etiolated mungbean (Phaseolus aureus) seedlings during germination. Accumulation of trigonelline (c. 240 nmol per pair of cotyledons) was observed in the cotyledons of dry seeds; trigonelline content decreased 2 d after imbibition. Trigonelline content in the embryonic axes increased with seedling growth and reached a peak (c. 380 nmol per embryonic axis) at day 5. Trigonelline content did not change significantly during the differentiation of hypocotyls, and the concentration was greatest in the apical 5 mm. Nicotinic acid and nicotinamide were better precursors for pyridine nucleotide synthesis than quinolinic acid, but no great differences were found in the synthesis of trigonelline from these three precursors. Trigonelline synthesis was always higher in embryonic axes than in cotyledons. Activity of quinolinate phosphoribosyltransferase (EC 2.4.2.19), nicotinate phosphoribosyltransferase (EC 2.4.2.11), and nicotinamidase (EC 3.5.1.19) was found in cotyledons and embryonic axes, but no nicotinamide phosphoribosyltransferase (EC 2.4.2.12) activity was detected. It follows that quinolinic acid and nicotinic acid were directly converted to nicotinic acid mononucleotide by the respective phosphoribosyltransferases, but nicotinamide appeared to be converted to nicotinic acid mononucleotide after conversion to nicotinic acid. Trigonelline synthase (nicotinate N-methyltransferase, EC 2.1.1.7) activity increased in the embryonic axes, but decreased in cotyledons during germination. [14C]Nicotinic acid and trigonelline absorbed by the cotyledons were transported to the embryonic axes during germination. Trigonelline had no effect on the growth of seedlings, but nicotinic acid and nicotinamide significantly inhibited the growth of roots. Based on these findings, the role of trigonelline synthesis in mungbean seedlings is discussed.
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Affiliation(s)
- Xin-Qiang Zheng
- Department of Advanced Biosciences, Graduate Division of Human Environmental Science, Graduate School of Humanities and Sciences, Ochanomizu University, Bunkyo-ku, Tokyo, 112-8610, Japan
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749
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Nemoto S, Fergusson MM, Finkel T. SIRT1 functionally interacts with the metabolic regulator and transcriptional coactivator PGC-1{alpha}. J Biol Chem 2005; 280:16456-60. [PMID: 15716268 DOI: 10.1074/jbc.m501485200] [Citation(s) in RCA: 837] [Impact Index Per Article: 44.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
In lower organisms, increased expression of the NAD-dependent deacetylase Sir2 augments lifespan. The mechanism through which this life extension is mediated remains incompletely understood. Here we have examined the cellular effects of overexpression of SIRT1, the closest mammalian ortholog of Sir2. In PC12 cells, increased expression of the NAD-dependent deacetylase SIRT1 reduces cellular oxygen consumption by approximately 25%. We further demonstrate that SIRT1 expression can alter the transcriptional activity of the mitochondrial biogenesis coactivator PGC-1alpha. In addition, SIRT1 and PGC-1alpha directly interact and can be co-immunoprecipitated as a molecular complex. A single amino acid mutation in the putative ADP-ribosyltransferase domain of SIRT1 inhibits the interaction of SIRT1 with PGC-1alpha but does not effect the interaction of SIRT1 with either p53 or Foxo3a. We further show that PGC-1alpha is acetylated in vivo. This acetylation is augmented by treatment with the SIRT1 inhibitor nicotinamide or by expression of the transcriptional coactivator p300. Finally we demonstrate that SIRT1 catalyzes PGC-1alpha deacetylation both in vitro and in vivo. These results provide a direct link between the sirtuins, a family of proteins linked to lifespan determination and PGC-1alpha, a coactivator that regulates cellular metabolism.
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Affiliation(s)
- Shino Nemoto
- Cardiovascular Branch, NHLBI, National Institutes of Health, Bethesda, Maryland 20892-1454, USA
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MESH Headings
- Acetylation
- Animals
- Caenorhabditis elegans Proteins/genetics
- Caenorhabditis elegans Proteins/physiology
- Cell Survival
- Forkhead Transcription Factors
- Gene Silencing
- Histone Deacetylases/physiology
- Insulin/physiology
- Longevity/genetics
- Mice
- Myocardium/metabolism
- Myocytes, Cardiac/cytology
- Nuclear Proteins/physiology
- Protein Processing, Post-Translational/genetics
- Rats
- Rats, Wistar
- Receptor, Insulin/genetics
- Receptor, Insulin/physiology
- Signal Transduction/genetics
- Silent Information Regulator Proteins, Saccharomyces cerevisiae/physiology
- Sirtuin 1
- Sirtuin 2
- Sirtuins/genetics
- Sirtuins/physiology
- Species Specificity
- Stress, Physiological/complications
- Stress, Physiological/genetics
- Stress, Physiological/metabolism
- Transcription Factors/physiology
- Transcription, Genetic
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