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Dillard LR, Wase N, Ramakrishnan G, Park JJ, Sherman NE, Carpenter R, Young M, Donlan AN, Petri W, Papin JA. Leveraging metabolic modeling to identify functional metabolic alterations associated with COVID-19 disease severity. Metabolomics 2022; 18:51. [PMID: 35819731 PMCID: PMC9273921 DOI: 10.1007/s11306-022-01904-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 06/01/2022] [Indexed: 01/18/2023]
Abstract
OBJECTIVE Since the COVID-19 pandemic began in early 2020, SARS-CoV2 has claimed more than six million lives world-wide, with over 510 million cases to date. To reduce healthcare burden, we must investigate how to prevent non-acute disease from progressing to severe infection requiring hospitalization. METHODS To achieve this goal, we investigated metabolic signatures of both non-acute (out-patient) and severe (requiring hospitalization) COVID-19 samples by profiling the associated plasma metabolomes of 84 COVID-19 positive University of Virginia hospital patients. We utilized supervised and unsupervised machine learning and metabolic modeling approaches to identify key metabolic drivers that are predictive of COVID-19 disease severity. Using metabolic pathway enrichment analysis, we explored potential metabolic mechanisms that link these markers to disease progression. RESULTS Enriched metabolites associated with tryptophan in non-acute COVID-19 samples suggest mitigated innate immune system inflammatory response and immunopathology related lung damage prevention. Increased prevalence of histidine- and ketone-related metabolism in severe COVID-19 samples offers potential mechanistic insight to musculoskeletal degeneration-induced muscular weakness and host metabolism that has been hijacked by SARS-CoV2 infection to increase viral replication and invasion. CONCLUSIONS Our findings highlight the metabolic transition from an innate immune response coupled with inflammatory pathway inhibition in non-acute infection to rampant inflammation and associated metabolic systemic dysfunction in severe COVID-19.
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Affiliation(s)
- L R Dillard
- Department of Biochemistry & Molecular Genetics, University of Virginia, Charlottesville, VA, 22908, USA
| | - N Wase
- School of Medicine Core Facilities, University of Virginia, Charlottesville, VA, 22908, USA
| | - G Ramakrishnan
- Department of Medicine, Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, 22908, USA
| | - J J Park
- School of Medicine Core Facilities, University of Virginia, Charlottesville, VA, 22908, USA
| | - N E Sherman
- School of Medicine Core Facilities, University of Virginia, Charlottesville, VA, 22908, USA
| | - R Carpenter
- Department of Medicine, Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, 22908, USA
| | - M Young
- Department of Medicine, Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, 22908, USA
| | - A N Donlan
- Department of Medicine, Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, 22908, USA
| | - W Petri
- Department of Medicine, Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, 22908, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia Health System, Charlottesville, VA, 22908, USA
| | - J A Papin
- Department of Biochemistry & Molecular Genetics, University of Virginia, Charlottesville, VA, 22908, USA.
- Department of Medicine, Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, 22908, USA.
- Department of Biomedical Engineering, University of Virginia, Health System, Box 800759, Charlottesville, VA, 22908, USA.
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Pesi R, Allegrini S, Garcia-Gil M, Piazza L, Moschini R, Jordheim LP, Camici M, Tozzi MG. Cytosolic 5'-Nucleotidase II Silencing in Lung Tumor Cells Regulates Metabolism through Activation of the p53/AMPK Signaling Pathway. Int J Mol Sci 2021; 22:ijms22137004. [PMID: 34209768 PMCID: PMC8268954 DOI: 10.3390/ijms22137004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 06/25/2021] [Accepted: 06/25/2021] [Indexed: 12/25/2022] Open
Abstract
Cytosolic 5′-nucleotidase II (cN-II) is an allosteric catabolic enzyme that hydrolyzes IMP, GMP, and AMP. The enzyme can assume at least two different structures, being the more active conformation stabilized by ATP and the less active by inorganic phosphate. Therefore, the variation in ATP concentration can control both structure and activity of cN-II. In this paper, using a capillary electrophoresis technique, we demonstrated that a partial silencing of cN-II in a pulmonary carcinoma cell line (NCI-H292) is accompanied by a decrease in adenylate pool, without affecting the energy charge. We also found that cN-II silencing decreased proliferation and increased oxidative metabolism, as indicated by the decreased production of lactate. These effects, as demonstrated by Western blotting, appear to be mediated by both p53 and AMP-activated protein kinase, as most of them are prevented by pifithrin-α, a known p53 inhibitor. These results are in line with our previous observations of a shift towards a more oxidative and less proliferative phenotype of tumoral cells with a low expression of cN-II, thus supporting the search for specific inhibitors of this enzyme as a therapeutic tool for the treatment of tumors.
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Affiliation(s)
- Rossana Pesi
- Unità di Biochimica, Dipartimento di Biologia, Università di Pisa, Via San Zeno 51, 56127 Pisa, Italy; (R.P.); (L.P.); (R.M.); (M.C.); (M.G.T.)
| | - Simone Allegrini
- Unità di Biochimica, Dipartimento di Biologia, Università di Pisa, Via San Zeno 51, 56127 Pisa, Italy; (R.P.); (L.P.); (R.M.); (M.C.); (M.G.T.)
- Interdepartmental Research Center Nutrafood “Nutraceuticals and Food for Health”, Università di Pisa, 56126 Pisa, Italy;
- CISUP, Centro per l’Integrazione della Strumentazione dell’Università di Pisa, 56127 Pisa, Italy
- Correspondence: ; Tel.: +39-050-221-1459
| | - Mercedes Garcia-Gil
- Interdepartmental Research Center Nutrafood “Nutraceuticals and Food for Health”, Università di Pisa, 56126 Pisa, Italy;
- CISUP, Centro per l’Integrazione della Strumentazione dell’Università di Pisa, 56127 Pisa, Italy
- Unità di Fisiologia Generale, Dipartimento di Biologia, Università di Pisa, Via San Zeno 31, 56127 Pisa, Italy
| | - Lucia Piazza
- Unità di Biochimica, Dipartimento di Biologia, Università di Pisa, Via San Zeno 51, 56127 Pisa, Italy; (R.P.); (L.P.); (R.M.); (M.C.); (M.G.T.)
| | - Roberta Moschini
- Unità di Biochimica, Dipartimento di Biologia, Università di Pisa, Via San Zeno 51, 56127 Pisa, Italy; (R.P.); (L.P.); (R.M.); (M.C.); (M.G.T.)
- Interdepartmental Research Center Nutrafood “Nutraceuticals and Food for Health”, Università di Pisa, 56126 Pisa, Italy;
- CISUP, Centro per l’Integrazione della Strumentazione dell’Università di Pisa, 56127 Pisa, Italy
| | - Lars Petter Jordheim
- Université de Lyon, Université Claude Bernard Lyon 1, INSERM 1052, CNRS 5286, Centre Léon Bérard, Centre de Recherche en Cancérologie de Lyon, 69008 Lyon, France;
| | - Marcella Camici
- Unità di Biochimica, Dipartimento di Biologia, Università di Pisa, Via San Zeno 51, 56127 Pisa, Italy; (R.P.); (L.P.); (R.M.); (M.C.); (M.G.T.)
| | - Maria Grazia Tozzi
- Unità di Biochimica, Dipartimento di Biologia, Università di Pisa, Via San Zeno 51, 56127 Pisa, Italy; (R.P.); (L.P.); (R.M.); (M.C.); (M.G.T.)
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Park JM, Park DH, Song Y, Kim JO, Choi JE, Kwon YJ, Kim SJ, Lee JW, Hong KW. Understanding the genetic architecture of the metabolically unhealthy normal weight and metabolically healthy obese phenotypes in a Korean population. Sci Rep 2021; 11:2279. [PMID: 33500527 PMCID: PMC7838176 DOI: 10.1038/s41598-021-81940-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 01/14/2021] [Indexed: 01/30/2023] Open
Abstract
Understanding the mechanisms underlying the metabolically unhealthy normal weight (MUHNW) and metabolically healthy obese (MHO) phenotypes is important for developing strategies to prevent cardiometabolic diseases. Here, we conducted genome-wide association studies (GWASs) to identify the MUHNW and MHO genetic indices. The study dataset comprised genome-wide single-nucleotide polymorphism genotypes and epidemiological data from 49,915 subjects categorised into four phenotypes-metabolically healthy normal weight (MHNW), MUHNW, MHO, and metabolically unhealthy obese (MUHO). We conducted two GWASs using logistic regression analyses and adjustments for confounding variables (model 1: MHNW versus MUHNW and model 2: MHO versus MUHO). GCKR, ABCB11, CDKAL1, LPL, CDKN2B, NT5C2, APOA5, CETP, and APOC1 were associated with metabolically unhealthy phenotypes among normal weight individuals (model 1). LPL, APOA5, and CETP were associated with metabolically unhealthy phenotypes among obese individuals (model 2). The genes common to both models are related to lipid metabolism (LPL, APOA5, and CETP), and those associated with model 1 are related to insulin or glucose metabolism (GCKR, CDKAL1, and CDKN2B). This study reveals the genetic architecture of the MUHNW and MHO phenotypes in a Korean population-based cohort. These findings could help identify individuals at a high metabolic risk in normal weight and obese populations and provide potential novel targets for the management of metabolically unhealthy phenotypes.
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Affiliation(s)
- Jae-Min Park
- grid.15444.300000 0004 0470 5454Department of Family Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonju‐ro, Gangnam-gu, Seoul, 06273 Korea ,grid.15444.300000 0004 0470 5454Department of Medicine, Graduate School of Medicine, Yonsei University, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722 Korea
| | - Da-Hyun Park
- Theragen Bio Co., Ltd., 145 Gwanggyo-ro, Suwon-si, Gyeonggi-do 16229 Korea
| | - Youhyun Song
- grid.15444.300000 0004 0470 5454Department of Family Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonju‐ro, Gangnam-gu, Seoul, 06273 Korea
| | - Jung Oh Kim
- Theragen Bio Co., Ltd., 145 Gwanggyo-ro, Suwon-si, Gyeonggi-do 16229 Korea
| | - Ja-Eun Choi
- Theragen Bio Co., Ltd., 145 Gwanggyo-ro, Suwon-si, Gyeonggi-do 16229 Korea
| | - Yu-Jin Kwon
- grid.15444.300000 0004 0470 5454Department of Family Medicine, Yongin Severance Hospital, Yonsei University College of Medicine, 363 Dongbaekjukjeon-daero, Giheung-gu, Yongin-si, Gyeonggi-do 16995 Korea
| | - Seong-Jin Kim
- Theragen Bio Co., Ltd., 145 Gwanggyo-ro, Suwon-si, Gyeonggi-do 16229 Korea
| | - Ji-Won Lee
- grid.15444.300000 0004 0470 5454Department of Family Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonju‐ro, Gangnam-gu, Seoul, 06273 Korea
| | - Kyung-Won Hong
- Theragen Bio Co., Ltd., 145 Gwanggyo-ro, Suwon-si, Gyeonggi-do 16229 Korea
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Chen X, Zhang Z, Wang X, Chen Y, Wang C. NT5C2 Gene Polymorphisms and the Risk of Coronary Heart Disease. Public Health Genomics 2020; 23:90-99. [PMID: 32541135 DOI: 10.1159/000507714] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 03/30/2020] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Increasing studies have reported that 5'-nucleotidase cytosolic II (NT5C2) has a strong relationship with coronary heart disease (CHD) development. This study was designed to examine the relationship between NT5C2 polymorphisms and CHD in the Chinese Han population. METHODS We studied 501 CHD patients and 496 healthy controls from the Second Affiliated Hospital of Hainan Medical University in Hainan Province, China. Four single nucleotide polymorphisms (SNPs) in NT5C2 were selected and genotyped using Agena MassARRAY technology. Odds ratios and 95% confidence intervals were calculated using logistic regression after adjusting for age and gender. Stratification analysis was performed by age and gender in all individuals; we especially investigated the effects of NT5C2 SNPs on hypertension and diabetes among CHD patients. RESULTS rs2148198 of NT5C2 was strongly associated with an increased risk of CHD (allele: p = 0.045; codominant: p = 0.007; additive: p = 0.016). Stratified analysis revealed that rs2148198 was associated with increased CHD risk in individuals aged ≤61 years and males. For CHD patients, rs2148198 significantly affected the risk of hypertension and diabetes (p < 0.05). Further, rs79237883 of NT5C2 was associated with decreased susceptibility to hypertension in multiple genetic models for individuals with CHD (allele: p = 0.007; codominant: p = 0.001; dominant: p = 0.001; additive: p = 0.008). CONCLUSION This study reports the association of NT5C2 gene variants and CHD susceptibility in the Chinese Han population. Especially, NT5C2 rs2148198 was significantly associated with CHD risk in the subgroups of males, hypertension, and diabetes.
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Affiliation(s)
- Xianghong Chen
- Department of General Medicine, The Second Affiliated Hospital of Hainan Medical University, Haikou, China
| | - Zaozhang Zhang
- Department of General Medicine, The Second Affiliated Hospital of Hainan Medical University, Haikou, China
| | - Xingfan Wang
- Department of Rehabilitative Medicine, The Second Affiliated Hospital of Hainan Medical University, Haikou, China
| | - Yuewu Chen
- Department of Cardiovascular Surgery, The Second Affiliated Hospital of Hainan Medical University, Haikou, China
| | - Chao Wang
- Department of General Medicine, The Second Affiliated Hospital of Hainan Medical University, Haikou, China,
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Emerging Role of Purine Metabolizing Enzymes in Brain Function and Tumors. Int J Mol Sci 2018; 19:ijms19113598. [PMID: 30441833 PMCID: PMC6274932 DOI: 10.3390/ijms19113598] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 11/09/2018] [Accepted: 11/12/2018] [Indexed: 12/13/2022] Open
Abstract
The growing evidence of the involvement of purine compounds in signaling, of nucleotide imbalance in tumorigenesis, the discovery of purinosome and its regulation, cast new light on purine metabolism, indicating that well known biochemical pathways may still surprise. Adenosine deaminase is important not only to preserve functionality of immune system but also to ensure a correct development and function of central nervous system, probably because its activity regulates the extracellular concentration of adenosine and therefore its function in brain. A lot of work has been done on extracellular 5′-nucleotidase and its involvement in the purinergic signaling, but also intracellular nucleotidases, which regulate the purine nucleotide homeostasis, play unexpected roles, not only in tumorigenesis but also in brain function. Hypoxanthine guanine phosphoribosyl transferase (HPRT) appears to have a role in the purinosome formation and, therefore, in the regulation of purine synthesis rate during cell cycle with implications in brain development and tumors. The final product of purine catabolism, uric acid, also plays a recently highlighted novel role. In this review, we discuss the molecular mechanisms underlying the pathological manifestations of purine dysmetabolisms, focusing on the newly described/hypothesized roles of cytosolic 5′-nucleotidase II, adenosine kinase, adenosine deaminase, HPRT, and xanthine oxidase.
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Kulikova V, Shabalin K, Nerinovski K, Dölle C, Niere M, Yakimov A, Redpath P, Khodorkovskiy M, Migaud ME, Ziegler M, Nikiforov A. Generation, Release, and Uptake of the NAD Precursor Nicotinic Acid Riboside by Human Cells. J Biol Chem 2015; 290:27124-27137. [PMID: 26385918 DOI: 10.1074/jbc.m115.664458] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Indexed: 12/31/2022] Open
Abstract
NAD is essential for cellular metabolism and has a key role in various signaling pathways in human cells. To ensure proper control of vital reactions, NAD must be permanently resynthesized. Nicotinamide and nicotinic acid as well as nicotinamide riboside (NR) and nicotinic acid riboside (NAR) are the major precursors for NAD biosynthesis in humans. In this study, we explored whether the ribosides NR and NAR can be generated in human cells. We demonstrate that purified, recombinant human cytosolic 5'-nucleotidases (5'-NTs) CN-II and CN-III, but not CN-IA, can dephosphorylate the mononucleotides nicotinamide mononucleotide and nicotinic acid mononucleotide (NAMN) and thus catalyze NR and NAR formation in vitro. Similar to their counterpart from yeast, Sdt1, the human 5'-NTs require high (millimolar) concentrations of nicotinamide mononucleotide or NAMN for efficient catalysis. Overexpression of FLAG-tagged CN-II and CN-III in HEK293 and HepG2 cells resulted in the formation and release of NAR. However, NAR accumulation in the culture medium of these cells was only detectable under conditions that led to increased NAMN production from nicotinic acid. The amount of NAR released from cells engineered for increased NAMN production was sufficient to maintain viability of surrounding cells unable to use any other NAD precursor. Moreover, we found that untransfected HeLa cells produce and release sufficient amounts of NAR and NR under normal culture conditions. Collectively, our results indicate that cytosolic 5'-NTs participate in the conversion of NAD precursors and establish NR and NAR as integral constituents of human NAD metabolism. In addition, they point to the possibility that different cell types might facilitate each other's NAD supply by providing alternative precursors.
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Affiliation(s)
- Veronika Kulikova
- Peter the Great St. Petersburg Polytechnic University, St. Petersburg 195251, Russia
| | - Konstantin Shabalin
- Peter the Great St. Petersburg Polytechnic University, St. Petersburg 195251, Russia,; Petersburg Nuclear Physics Institute, National Research Centre Kurchatov Institute, Gatchina 188300, Russia
| | - Kirill Nerinovski
- Peter the Great St. Petersburg Polytechnic University, St. Petersburg 195251, Russia,; St. Petersburg State University, St. Petersburg 199034, Russia
| | - Christian Dölle
- Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway
| | - Marc Niere
- Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway
| | - Alexander Yakimov
- Peter the Great St. Petersburg Polytechnic University, St. Petersburg 195251, Russia,; Petersburg Nuclear Physics Institute, National Research Centre Kurchatov Institute, Gatchina 188300, Russia
| | - Philip Redpath
- School of Pharmacy, Queen's University Belfast, Belfast BT9 7BL, Northern Ireland, United Kingdom
| | - Mikhail Khodorkovskiy
- Peter the Great St. Petersburg Polytechnic University, St. Petersburg 195251, Russia
| | - Marie E Migaud
- School of Pharmacy, Queen's University Belfast, Belfast BT9 7BL, Northern Ireland, United Kingdom
| | - Mathias Ziegler
- Department of Molecular Biology, University of Bergen, 5020 Bergen, Norway,.
| | - Andrey Nikiforov
- Peter the Great St. Petersburg Polytechnic University, St. Petersburg 195251, Russia,; Institute of Cytology, Russian Academy of Sciences, St. Petersburg 194064, Russia.
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Allegrini S, Filoni DN, Galli A, Collavoli A, Pesi R, Camici M, Tozzi MG. Expression of bovine cytosolic 5'-nucleotidase (cN-II) in yeast: nucleotide pools disturbance and its consequences on growth and homologous recombination. PLoS One 2013; 8:e63914. [PMID: 23691116 PMCID: PMC3656857 DOI: 10.1371/journal.pone.0063914] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 04/09/2013] [Indexed: 01/30/2023] Open
Abstract
Cytosolic 5'-nucleotidase II is a widespread IMP hydrolyzing enzyme, essential for cell vitality, whose role in nucleotide metabolism and cell function is still to be exactly determined. Cytosolic 5'-nucleotidase overexpression and silencing have both been demonstrated to be toxic for mammalian cultured cells. In order to ascertain the effect of enzyme expression on a well-known eukaryote simple model, we expressed cytosolic 5'-nucleotidase II in Saccharomyces cerevisiae, which normally hydrolyzes IMP through the action of a nucleotidase with distinct functional and structural features. Heterologous expression was successful. The yeast cells harbouring cytosolic 5'-nucleotidase II displayed a shorter duplication time and a significant modification of purine and pyrimidine derivatives concentration as compared with the control strain. Furthermore the capacity of homologous recombination in the presence of mutagenic compounds of yeast expressing cytosolic 5'-nucleotidase II was markedly impaired.
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Affiliation(s)
- Simone Allegrini
- Dipartimento di Chimica e Farmacia, Università di Sassari, Sassari, Italy.
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Metabolic activation of the anti-hepatitis C virus nucleotide prodrug PSI-352938. Antimicrob Agents Chemother 2012; 56:3767-75. [PMID: 22526308 DOI: 10.1128/aac.00530-12] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
PSI-352938 is a novel cyclic phosphate prodrug of β-D-2'-deoxy-2'-α-fluoro-2'-β-C-methylguanosine-5'-monophosphate with potent anti-HCV activity. In order to inhibit the NS5B RNA-dependent RNA polymerase, PSI-352938 must be metabolized to the active triphosphate form, PSI-352666. During in vitro incubations with PSI-352938, significantly larger amounts of PSI-352666 were formed in primary hepatocytes than in clone A hepatitis C virus (HCV) replicon cells. Metabolism and biochemical assays were performed to define the molecular mechanism of PSI-352938 activation. The first step, removal of the isopropyl group on the 3',5'-cyclic phosphate moiety, was found to be cytochrome P450 (CYP) 3A4 dependent, with other CYP isoforms unable to catalyze the reaction. The second step, opening of the cyclic phosphate ring, was catalyzed by phosphodiesterases (PDEs) 2A1, 5A, 9A, and 11A4, all known to be expressed in the liver. The role of these enzymes in the activation of PSI-352938 was confirmed in primary human hepatocytes, where prodrug activation was reduced by inhibitors of CYP3A4 and PDEs. The third step, removal of the O(6)-ethyl group on the nucleobase, was shown to be catalyzed by adenosine deaminase-like protein 1. The resulting monophosphate was consecutively phosphorylated to the diphosphate and to the triphosphate PSI-352666 by guanylate kinase 1 and nucleoside diphosphate kinase, respectively. In addition, formation of nucleoside metabolites was observed in primary hepatocytes, and ecto-5'-nucleotidase was able to dephosphorylate the monophosphate metabolites. Since CYP3A4 is highly expressed in the liver, the CYP3A4-dependent metabolism of PSI-352938 makes it an effective liver-targeted prodrug, in part accounting for the potent antiviral activity observed clinically.
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Grazia TM. Inborn errors in purine metabolism: role of 5'-nucleotidases and their involvement in the etiology of neurological impairments. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2012; 30:1276-83. [PMID: 22132987 DOI: 10.1080/15257770.2011.616869] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Abstract
A number of scientists have been involved for decades in the study of nucleotide metabolism in different species of living beings. We are, therefore, aware of the relevant roles of purine compounds and of the many different ways in which these compounds influence cell life, acting both inside and outside the cells. Nevertheless, the consequences of an alteration (lack of expression, or hypo- or hyperexpression) in the activity of enzymes involved in the metabolism of these compounds are sometimes surprising, and far from being mechanistically explained. Alterations in enzyme activities involved in nucleotide metabolism are frequently associated with syndromes characterized by two different types of problems--one, metabolic, which is expected and can be easily explained, and the second, neurological and behavioral. Neurological and behavioral impairments are more difficult to explain and show a very high degree of individual variability. The molecular bases of the neurological impairment linked to purine metabolism disorders have been extensively studied. These studies have generated a lot of hypotheses but very few certainties. In this short review, neurological and behavioral symptoms linked to the dysfunction of some enzymes involved in purine synthesis, catabolism, and salvage will be briefly described, with particular attention to their metabolic and regulatory consequences. Finally, attention will be focused on the 5'-nucleotidase family members and on their involvement in the regulation of purine and pyrimidine metabolism.
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Camici M, Micheli V, Ipata PL, Tozzi MG. Pediatric neurological syndromes and inborn errors of purine metabolism. Neurochem Int 2009; 56:367-78. [PMID: 20005278 DOI: 10.1016/j.neuint.2009.12.003] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 11/25/2009] [Accepted: 12/03/2009] [Indexed: 11/17/2022]
Abstract
This review is devised to gather the presently known inborn errors of purine metabolism that manifest neurological pediatric syndromes. The aim is to draw a comprehensive picture of these rare diseases, characterized by unexpected and often devastating neurological symptoms. Although investigated for many years, most purine metabolism disorders associated to psychomotor dysfunctions still hide the molecular link between the metabolic derangement and the neurological manifestations. This basically indicates that many of the actual functions of nucleosides and nucleotides in the development and function of several organs, in particular central nervous system, are still unknown. Both superactivity and deficiency of phosphoribosylpyrophosphate synthetase cause hereditary disorders characterized, in most cases, by neurological impairments. The deficiency of adenylosuccinate lyase and 5-amino-4-imidazolecarboxamide ribotide transformylase/IMP cyclohydrolase, both belonging to the de novo purine synthesis pathway, is also associated to severe neurological manifestations. Among catabolic enzymes, hyperactivity of ectosolic 5'-nucleotidase, as well as deficiency of purine nucleoside phosphorylase and adenosine deaminase also lead to syndromes affecting the central nervous system. The most severe pathologies are associated to the deficiency of the salvage pathway enzymes hypoxanthine-guanine phosphoribosyltransferase and deoxyguanosine kinase: the former due to an unexplained adverse effect exerted on the development and/or differentiation of dopaminergic neurons, the latter due to a clear impairment of mitochondrial functions. The assessment of hypo- or hyperuricemic conditions is suggestive of purine enzyme dysfunctions, but most disorders of purine metabolism may escape the clinical investigation because they are not associated to these metabolic derangements. This review may represent a starting point stimulating both scientists and physicians involved in the study of neurological dysfunctions caused by inborn errors of purine metabolism with the aim to find novel therapeutical approaches.
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Affiliation(s)
- Marcella Camici
- Dipartimento di Biologia, Unità di Biochimica, Via S Zeno 51, 56127 Pisa, Italy.
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López JM. Is ZMP the toxic metabolite in Lesch-Nyhan disease? Med Hypotheses 2008; 71:657-63. [PMID: 18710792 DOI: 10.1016/j.mehy.2008.06.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Revised: 06/23/2008] [Accepted: 06/26/2008] [Indexed: 11/17/2022]
Abstract
The genetic deficiency of hypoxanthine-guanine phosphoribosyltransferase (HPRT), located on the X chromosome, causes a severe neurological disorder in man, known as Lesch-Nyhan disease (LND). The enzyme HPRT is part of the savage pathway of purine biosynthesis and catalyzes the conversion of hypoxanthine and guanine to their respective nucleotides, IMP and GMP. HPRT deficiency is associated with a relatively selective dysfunction of brain dopamine systems. Several metabolites that accumulate in the patients (phosphoribosylpyrophosphate (PRPP), hypoxanthine, guanine, xanthine, and Z-nucleotides) have been proposed as toxic agents in LND. Some authors have pointed that Z-riboside, derived from the accumulation of ZMP, could be the toxic metabolite in LND. However, the available experimental data support a better hypothesis. I suggest that ZMP (and not Z-riboside) is the key toxic metabolite in LND. ZMP is an inhibitor of the bifunctional enzyme adenylosuccinate lyase, and a deficiency of this enzyme causes psychomotor and mental retardation in humans. Moreover, it has been reported that ZMP inhibits mitochondrial oxidative phosphorylation and induces apoptosis in certain cell types. ZMP is also an activator of the AMP-activated protein kinase (AMPK), a homeostatic regulator of energy levels in the cell. The AMPK has been implicated in the regulation of cell viability, catecholamine biosynthesis and cell structure. I propose that accumulation of ZMP will induce a pleiotropic effect in the brain by (1) a direct inhibition of mitochondrial respiration and the bifunctional enzyme adenylosuccinate lyase, and (2) a sustained activation of the AMPK which in turns would reduce cell viability, decrease dopamine synthesis, and alters cell morphology. In addition, a mechanism to explain the accumulation of ZMP in LND is presented. The knowledge of the toxic metabolite, and the way it acts, would help to design a better therapy.
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Affiliation(s)
- José M López
- Institut de Neurociencies, Departament de Bioquímica i Biología Molecular, Unitat de Bioquímica, Facultad de Medicina, Universitat Autónoma de Barcelona, 08193 Cerdanyola del Vallès. Barcelona, Spain.
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