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Teoh ST, Leimanis-Laurens ML, Comstock SS, Winters JW, Vandenbosch NL, Prokop JW, Bachmann AS, Lunt SY, Rajasekaran S. Combined Plasma and Urinary Metabolomics Uncover Metabolic Perturbations Associated with Severe Respiratory Syncytial Viral Infection and Future Development of Asthma in Infant Patients. Metabolites 2022; 12:metabo12020178. [PMID: 35208252 PMCID: PMC8875115 DOI: 10.3390/metabo12020178] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/21/2022] [Accepted: 02/11/2022] [Indexed: 02/05/2023] Open
Abstract
A large percentage of infants develop viral bronchiolitis needing medical intervention and often develop further airway disease such as asthma. To characterize metabolic perturbations in acute respiratory syncytial viral (RSV) bronchiolitis, we compared metabolomic profiles of moderate and severe RSV patients versus sedation controls. RSV patients were classified as moderate or severe based on the need for invasive mechanical ventilation. Whole blood and urine samples were collected at two time points (baseline and 72 h). Plasma and urinary metabolites were extracted in cold methanol and analyzed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS), and data from the two biofluids were combined for multivariate data analysis. Metabolite profiles were clustered according to severity, characterized by unique metabolic changes in both plasma and urine. Plasma metabolites that correlated with severity included intermediates in the sialic acid biosynthesis, while urinary metabolites included citrate as well as multiple nucleotides. Furthermore, metabolomic profiles were predictive of future development of asthma, with urinary metabolites exhibiting higher predictive power than plasma. These metabolites may offer unique insights into the pathology of RSV bronchiolitis and may be useful in identifying patients at risk for developing asthma.
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Affiliation(s)
- Shao Thing Teoh
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA;
| | - Mara L. Leimanis-Laurens
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA; (M.L.L.-L.); (J.W.W.); (J.W.P.); (A.S.B.)
- Pediatric Intensive Care Unit, Helen DeVos Children’s Hospital, Grand Rapids, MI 49503, USA;
| | - Sarah S. Comstock
- Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI 48824, USA;
| | - John W. Winters
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA; (M.L.L.-L.); (J.W.W.); (J.W.P.); (A.S.B.)
- Pediatric Intensive Care Unit, Helen DeVos Children’s Hospital, Grand Rapids, MI 49503, USA;
| | - Nikita L. Vandenbosch
- Pediatric Intensive Care Unit, Helen DeVos Children’s Hospital, Grand Rapids, MI 49503, USA;
| | - Jeremy W. Prokop
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA; (M.L.L.-L.); (J.W.W.); (J.W.P.); (A.S.B.)
| | - André S. Bachmann
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA; (M.L.L.-L.); (J.W.W.); (J.W.P.); (A.S.B.)
| | - Sophia Y. Lunt
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA;
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI 48824, USA
- Correspondence: (S.Y.L.); (S.R.)
| | - Surender Rajasekaran
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA; (M.L.L.-L.); (J.W.W.); (J.W.P.); (A.S.B.)
- Pediatric Intensive Care Unit, Helen DeVos Children’s Hospital, Grand Rapids, MI 49503, USA;
- Office of Research, Spectrum Health, Grand Rapids, MI 49503, USA
- Correspondence: (S.Y.L.); (S.R.)
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Pinho BR, Reis SD, Hartley RC, Murphy MP, Oliveira JMA. Mitochondrial superoxide generation induces a parkinsonian phenotype in zebrafish and huntingtin aggregation in human cells. Free Radic Biol Med 2019; 130:318-327. [PMID: 30389496 PMCID: PMC6340810 DOI: 10.1016/j.freeradbiomed.2018.10.446] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/28/2018] [Accepted: 10/29/2018] [Indexed: 01/21/2023]
Abstract
Superoxide generation by mitochondria respiratory complexes is a major source of reactive oxygen species (ROS) which are capable of initiating redox signaling and oxidative damage. Current understanding of the role of mitochondrial ROS in health and disease has been limited by the lack of experimental strategies to selectively induce mitochondrial superoxide production. The recently-developed mitochondria-targeted redox cycler MitoParaquat (MitoPQ) overcomes this limitation, and has proven effective in vitro and in Drosophila. Here we present an in vivo study of MitoPQ in the vertebrate zebrafish model in the context of Parkinson's disease (PD), and in a human cell model of Huntington's disease (HD). We show that MitoPQ is 100-fold more potent than non-targeted paraquat in both cells and in zebrafish in vivo. Treatment with MitoPQ induced a parkinsonian phenotype in zebrafish larvae, with decreased sensorimotor reflexes, spontaneous movement and brain tyrosine hydroxylase (TH) levels, without detectable effects on heart rate or atrioventricular coordination. Motor phenotypes and TH levels were partly rescued with antioxidant or monoaminergic potentiation strategies. In a HD cell model, MitoPQ promoted mutant huntingtin aggregation without increasing cell death, contrasting with the complex I inhibitor rotenone that increased death in cells expressing either wild-type or mutant huntingtin. These results show that MitoPQ is a valuable tool for cellular and in vivo studies of the role of mitochondrial superoxide generation in redox biology, and as a trigger or co-stressor to model metabolic and neurodegenerative disease phenotypes.
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Affiliation(s)
- Brígida R Pinho
- REQUIMTE/LAQV, Department of Drug Sciences, Pharmacology Lab, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal
| | - Sara D Reis
- REQUIMTE/LAQV, Department of Drug Sciences, Pharmacology Lab, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal
| | - Richard C Hartley
- WestCHEM School of Chemistry, University of Glasgow, Glasgow G12 8QQ, UK
| | - Michael P Murphy
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Jorge M A Oliveira
- REQUIMTE/LAQV, Department of Drug Sciences, Pharmacology Lab, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal; Consortium for Mitochondrial Research (CfMR), University College London, Gower Street, WC1E 6BT London, UK.
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Abstract
Traditionally, only the 3',5'-cyclic monophosphates of adenosine and guanosine (produced by adenylyl cyclase and guanylyl cyclase, respectively) are regarded as true "second messengers" in the vascular wall, despite the presence of other cyclic nucleotides in different tissues. Among these noncanonical cyclic nucleotides, inosine 3',5'-cyclic monophosphate (cIMP) is synthesized by soluble guanylyl cyclase in porcine coronary arteries in response to hypoxia, when the enzyme is activated by endothelium-derived nitric oxide. Its production is associated with augmentation of vascular contraction mediated by stimulation of Rho kinase. Based on these findings, cIMP appears to meet most, if not all, of the criteria required for it to be accepted as a "second messenger," at least in the vascular wall.
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Zhu X, Wu G, Lu N, Yuan X, Li B. A miniaturized electrochemical toxicity biosensor based on graphene oxide quantum dots/carboxylated carbon nanotubes for assessment of priority pollutants. JOURNAL OF HAZARDOUS MATERIALS 2017; 324:272-280. [PMID: 27810324 DOI: 10.1016/j.jhazmat.2016.10.057] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Revised: 10/14/2016] [Accepted: 10/24/2016] [Indexed: 06/06/2023]
Abstract
The study presented a sensitive and miniaturized cell-based electrochemical biosensor to assess the toxicity of priority pollutants in the aquatic environment. Human hepatoma (HepG2) cells were used as the biological recognition agent to measure the changes of electrochemical signals and reflect the cell viability. The graphene oxide quantum dots/carboxylated carbon nanotubes hybrid was developed in a facile and green way. Based on the hybrid composite modified pencil graphite electrode, the cell culture and detection vessel was miniaturized to a 96-well plate instead of the traditional culture dish. In addition, three sensitive electrochemical signals attributed to guanine/xanthine, adenine, and hypoxanthine were detected simultaneously. The biosensor was used to evaluate the toxicity of six priority pollutants, including Cd, Hg, Pb, 2,4-dinitrophenol, 2,4,6-trichlorophenol, and pentachlorophenol. The 24h IC50 values obtained by the electrochemical biosensor were lower than those of conventional MTT assay, suggesting the enhanced sensitivity of the electrochemical assay towards heavy metals and phenols. This platform enables the label-free and sensitive detection of cell physiological status with multi-parameters and constitutes a promising approach for toxicity detection of pollutants. It makes possible for automatical and high-throughput analysis on nucleotide catabolism, which may be critical for life science and toxicology.
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Affiliation(s)
- Xiaolin Zhu
- School of Environment, Northeast Normal University, Changchun 130117, PR China
| | - Guanlan Wu
- School of Environment, Northeast Normal University, Changchun 130117, PR China
| | - Nan Lu
- School of Environment, Northeast Normal University, Changchun 130117, PR China
| | - Xing Yuan
- School of Environment, Northeast Normal University, Changchun 130117, PR China.
| | - Baikun Li
- Department of Civil and Environmental Engineering, University of Connecticut, Storrs, CT 06269, United States.
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Thimm D, Schiedel AC, Peti-Peterdi J, Kishore BK, Müller CE. The nucleobase adenine as a signalling molecule in the kidney. Acta Physiol (Oxf) 2015; 213:808-18. [PMID: 25627062 DOI: 10.1111/apha.12452] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 12/07/2014] [Accepted: 01/05/2015] [Indexed: 11/30/2022]
Abstract
In 2002, the first receptor activated by the nucleobase adenine was discovered in rats. In the past years, two adenine receptors (AdeRs) in mice and one in Chinese hamsters, all of which belong to the family of G protein-coupled receptors (GPCRs), were cloned and pharmacologically characterized. Based on the nomenclature for other purinergic receptor families (P1 for adenosine receptors and P2 for nucleotide, e.g. ATP, receptors), AdeRs were designated P0 receptors. Pharmacological data indicate the existence of G protein-coupled AdeRs in pigs and humans as well; however, those have not been cloned so far. Current data suggest a role for adenine and AdeRs in renal proximal tubules. Furthermore, AdeRs are suggested to be functional counterplayers of vasopressin in the collecting duct system, thus exerting diuretic effects. We are only at the beginning of understanding the significance of this new class of purinergic receptors, which might become future drug targets.
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Affiliation(s)
- D. Thimm
- PharmaCenter Bonn; Pharmaceutical Institute, Pharmaceutical Chemistry I; University of Bonn; Bonn Germany
| | - A. C. Schiedel
- PharmaCenter Bonn; Pharmaceutical Institute, Pharmaceutical Chemistry I; University of Bonn; Bonn Germany
| | - J. Peti-Peterdi
- Department of Physiology and Biophysics; Zilkha Neurogenetic Institute; University of Southern California; Los Angeles CA USA
- Department of Medicine; Zilkha Neurogenetic Institute; University of Southern California; Los Angeles CA USA
| | - B. K. Kishore
- Nephrology Research; Department of Veterans Affairs Salt Lake City Health Care System; Salt Lake City UT USA
- Department of Internal Medicine; University of Utah Health Sciences Center; Salt Lake City UT USA
- Center on Aging; University of Utah Health Sciences Center; Salt Lake City UT USA
| | - C. E. Müller
- PharmaCenter Bonn; Pharmaceutical Institute, Pharmaceutical Chemistry I; University of Bonn; Bonn Germany
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6
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Metabolic phenotypes of Saccharomyces cerevisiae mutants with altered trehalose 6-phosphate dynamics. Biochem J 2013; 454:227-37. [PMID: 23763276 DOI: 10.1042/bj20130587] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In Saccharomyces cerevisiae, synthesis of T6P (trehalose 6-phosphate) is essential for growth on most fermentable carbon sources. In the present study, the metabolic response to glucose was analysed in mutants with different capacities to accumulate T6P. A mutant carrying a deletion in the T6P synthase encoding gene, TPS1, which had no measurable T6P, exhibited impaired ethanol production, showed diminished plasma membrane H⁺-ATPase activation, and became rapidly depleted of nearly all adenine nucleotides which were irreversibly converted into inosine. Deletion of the AMP deaminase encoding gene, AMD1, in the tps1 strain prevented inosine formation, but did not rescue energy balance or growth on glucose. Neither the 90%-reduced T6P content observed in a tps1 mutant expressing the Tps1 protein from Yarrowia lipolytica, nor the hyperaccumulation of T6P in the tps2 mutant had significant effects on fermentation rates, growth on fermentable carbon sources or plasma membrane H⁺-ATPase activation. However, intracellular metabolite dynamics and pH homoeostasis were strongly affected by changes in T6P concentrations. Hyperaccumulation of T6P in the tps2 mutant caused an increase in cytosolic pH and strongly reduced growth rates on non-fermentable carbon sources, emphasizing the crucial role of the trehalose pathway in the regulation of respiratory and fermentative metabolism.
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zur Nedden S, Doney AS, Frenguelli BG. Modulation of intracellular ATP determines adenosine release and functional outcome in response to metabolic stress in rat hippocampal slices and cerebellar granule cells. J Neurochem 2013; 128:111-24. [PMID: 23937448 DOI: 10.1111/jnc.12397] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 07/30/2013] [Accepted: 08/06/2013] [Indexed: 11/24/2022]
Abstract
Cerebral ischaemia rapidly depletes cellular ATP. Whilst this deprives brain tissue of a valuable energy source, the concomitant production of adenosine mitigates the damaging effects of energy failure by suppressing neuronal activity. However, the production of adenosine and other metabolites, and their loss across the blood-brain barrier, deprives the brain of substrates for the purine salvage pathway, the primary means by which the brain makes ATP. Because of this, cerebral ATP levels remain depressed after brain injury. To test whether manipulating cellular ATP levels in brain tissue could affect functional neuronal outcomes in response to oxygen/glucose deprivation (OGD), we examined the effects of creatine and d-ribose and adenine (RibAde). In hippocampal slices creatine delayed ATP breakdown, reduced adenosine release, retarded both the depression of synaptic transmission and the anoxic depolarization caused by OGD, and improved the recovery of transmission. In contrast, RibAde increased cellular ATP, caused increased OGD-induced adenosine release and accelerated the depression of synaptic transmission, but did not improve functional recovery. However, RibAde improved the viability of cerebellar granule cells when administered after OGD. Our data indicate that RibAde may be effective in promoting recovery of brain tissue after injury, potentially via enhancement of salvage-mediated ATP production.
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López-Cánovas F, Gomes PJF, Sillero A. Mathematica program: its use to simulate metabolic irreversible pathways and inhibition of the first enzyme of a pathway by its end product as visualized with the reservoir model. Comput Biol Med 2013; 43:853-64. [PMID: 23746727 DOI: 10.1016/j.compbiomed.2013.04.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 04/02/2013] [Accepted: 04/03/2013] [Indexed: 11/19/2022]
Abstract
The main objective of this report is to show the usefulness and versatility of the Mathematica program to simulate enzyme linear pathways and to depict the effect of changing the Vmax and/or Km values of one or more enzymes on the course of the reaction. In addition, analysis of the different types of inhibition of the first enzyme of the pathway by its end product is viewed with the reservoir model for enzyme kinetics. All the data shown here are quantitatively related to the kinetic constants of the implicated enzymes. Particular attention has been paid to calculate the time needed to achieve half of the possible total synthesis of the final product of a metabolic pathway.
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Affiliation(s)
- Francisco López-Cánovas
- Departamento de Bioquímica, Facultad de Medicina, Instituto de Investigaciones Biomédicas Alberto Sols UAM/CSIC, Arzobispo Morcillo, 4, Madrid, 28029, Spain
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Prado S, Villamarín A, Ibarguren I. SIMULTANEOUS DETERMINATION OF ADENOSINE AND RELATED PURINES IN TISSUES AND HEMOLYMPH OF MUSSEL BY HPLC. J LIQ CHROMATOGR R T 2013. [DOI: 10.1080/10826076.2012.660723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Sonia Prado
- a Department of Biochemistry and Molecular Biology, Faculty of Veterinary Science , University of Santiago de Compostela , Lugo , Spain
| | - Antonio Villamarín
- a Department of Biochemistry and Molecular Biology, Faculty of Veterinary Science , University of Santiago de Compostela , Lugo , Spain
| | - Izaskun Ibarguren
- a Department of Biochemistry and Molecular Biology, Faculty of Veterinary Science , University of Santiago de Compostela , Lugo , Spain
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Shirakawa H, Koseki T, Hiwatashi K, Takahasi S, Akiyama Y, Komai M. Novel effect of adenosine 5'-monophosphate on ameliorating hypertension and the metabolism of lipids and glucose in stroke-prone spontaneously hypertensive rats. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:13238-13245. [PMID: 22103713 DOI: 10.1021/jf203237c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The aim of the study was to investigate the effects of adenosine 5'-monophosphate (AMP) in stroke-prone spontaneously hypertensive rats (SHRSP). Male rats (10 weeks old) were divided into three groups: a control group fed an AIN-93 M diet and two others fed supplemental AMP (17.5 and 87.5 mg/kg diet) for 3 weeks. AMP effectively improved hypertension, plasma triglyceride, and HDL-cholesterol, glucose, kidney function parameters, hepatic lipid, enhances plasma nitric oxide, and plasma adiponectin accompanied by the up-regulation of mRNA expression levels of the hepatic adiponectin receptor 2. Single and chronic oral administration of AMP affected the hepatic mRNA expression levels of genes involved in β-oxidation, fatty acid synthesis, and AMP-activated protein kinase. Furthermore, a single oral dose of AMP (40 mg/kg body weight) improved hypertension and hyperglycemia in SHRSP. In conclusion, AMP displays a novel effect in ameliorating metabolic-related diseases in SHRSP and could be beneficial as a functional food.
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Badrian B, Bogoyevitch MA. Changes in the transcriptional profile of cardiac myocytes following green fluorescent protein expression. DNA Cell Biol 2008; 26:727-36. [PMID: 17723104 DOI: 10.1089/dna.2007.0604] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Green fluorescent protein (GFP) and its multiple forms, such as enhanced GFP (EGFP), have been widely used as marker proteins and for tracking purposes in many biological systems, including the heart and cardiac cell systems. Despite some concerns on its toxicity under certain circumstances, GFP remains amongst the most reliable and easy-to-use markers available. Using rat full genome DNA microarrays, we have investigated the broader consequences of adenoviral-driven GFP expression in cardiac myocytes. In our transcriptional profiling analysis, we set a threshold of a twofold change. We removed possible changes resulting from adenoviral infection by comparison with transcriptional profiles of cardiac myocytes with adenoviral-driven expression of an unrelated protein, the kinase MEK. Our analysis revealed changes in the expression of 212 genes. Of these genes, 174 were upregulated and 38 were downregulated following GFP expression. Many of these genes remain unannotated, but an evaluation of those with described functions for their resulting proteins indicated that many were involved in processes, including responses to stimuli/stress and signal transduction. Our analysis thus indicates the broader consequences of GFP expression in altering gene expression profiles in cardiac cells. Care should therefore be taken when using GFP expression as a control in gene expression studies.
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Affiliation(s)
- Bahareh Badrian
- Biochemistry and Molecular Biology, School of Biomedical, Biomolecular, and Chemical Sciences, University of Western Australia, Perth, Western Australia, Australia.
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Tozzi MG, Camici M, Mascia L, Sgarrella F, Ipata PL. Pentose phosphates in nucleoside interconversion and catabolism. FEBS J 2006; 273:1089-101. [PMID: 16519676 DOI: 10.1111/j.1742-4658.2006.05155.x] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ribose phosphates are either synthesized through the oxidative branch of the pentose phosphate pathway, or are supplied by nucleoside phosphorylases. The two main pentose phosphates, ribose-5-phosphate and ribose-1-phosphate, are readily interconverted by the action of phosphopentomutase. Ribose-5-phosphate is the direct precursor of 5-phosphoribosyl-1-pyrophosphate, for both de novo and 'salvage' synthesis of nucleotides. Phosphorolysis of deoxyribonucleosides is the main source of deoxyribose phosphates, which are interconvertible, through the action of phosphopentomutase. The pentose moiety of all nucleosides can serve as a carbon and energy source. During the past decade, extensive advances have been made in elucidating the pathways by which the pentose phosphates, arising from nucleoside phosphorolysis, are either recycled, without opening of their furanosidic ring, or catabolized as a carbon and energy source. We review herein the experimental knowledge on the molecular mechanisms by which (a) ribose-1-phosphate, produced by purine nucleoside phosphorylase acting catabolically, is either anabolized for pyrimidine salvage and 5-fluorouracil activation, with uridine phosphorylase acting anabolically, or recycled for nucleoside and base interconversion; (b) the nucleosides can be regarded, both in bacteria and in eukaryotic cells, as carriers of sugars, that are made available though the action of nucleoside phosphorylases. In bacteria, catabolism of nucleosides, when suitable carbon and energy sources are not available, is accomplished by a battery of nucleoside transporters and of inducible catabolic enzymes for purine and pyrimidine nucleosides and for pentose phosphates. In eukaryotic cells, the modulation of pentose phosphate production by nucleoside catabolism seems to be affected by developmental and physiological factors on enzyme levels.
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Affiliation(s)
- Maria G Tozzi
- Dipartimento di Biologia, Laboratorio di Biochimica, Pisa, Italy
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Barsotti C, Pesi R, Giannecchini M, Ipata PL. Evidence for the involvement of cytosolic 5'-nucleotidase (cN-II) in the synthesis of guanine nucleotides from xanthosine. J Biol Chem 2005; 280:13465-9. [PMID: 15699053 DOI: 10.1074/jbc.m413347200] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In this paper, we show that in vitro xanthosine does not enter any of the pathways known to salvage the other three main natural purine nucleosides: guanosine; inosine; and adenosine. In rat brain extracts and in intact LoVo cells, xanthosine is salvaged to XMP via the phosphotransferase activity of cytosolic 5'-nucleotidase. IMP is the preferred phosphate donor (IMP + xanthosine --> XMP + inosine). XMP is not further phosphorylated. However, in the presence of glutamine, it is readily converted to guanyl compounds. Thus, phosphorylation of xanthosine by cytosolic 5'-nucleotidase circumvents the activity of IMP dehydrogenase, a rate-limiting enzyme, catalyzing the NAD(+)-dependent conversion of IMP to XMP at the branch point of de novo nucleotide synthesis, thus leading to the generation of guanine nucleotides. Mycophenolic acid, an inhibitor of IMP dehydrogenase, inhibits the guanyl compound synthesis via the IMP dehydrogenase pathway but has no effect on the cytosolic 5'-nucleotidase pathway of guanine nucleotides synthesis. We propose that the latter pathway might contribute to the reversal of the in vitro antiproliferative effect exerted by IMP dehydrogenase inhibitors routinely seen with repletion of the guanine nucleotide pools.
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Affiliation(s)
- Catia Barsotti
- Department of Physiology and Biochemistry, University of Pisa, Via San Zeno 51, 56127 Pisa, Italy
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14
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Barsotti C, Ipata PL. Metabolic regulation of ATP breakdown and of adenosine production in rat brain extracts. Int J Biochem Cell Biol 2005; 36:2214-25. [PMID: 15313467 DOI: 10.1016/j.biocel.2004.04.015] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2004] [Revised: 04/28/2004] [Accepted: 04/28/2004] [Indexed: 02/07/2023]
Abstract
ATP concentration is dramatically affected in ischemic injury. From previous studies on ATP mediated purine and pyrimidine salvage in CNS, we observed that when "post-mitochondrial" extracts of rat brain were incubated with ATP at 3.6 mM, a normoxic concentration, formation of IMP always preceded that of adenosine, a well known neuroactive nucleoside and a homeostatic cellular modulator. This observation prompted us to undertake a study aimed at assessing the precise pathways and kinetics of ATP breakdown, a process considered to be the major source of adenosine in rat brain. The results obtained using post-mitochondrial extracts strongly suggest that the breakdown of intracellular ATP at normoxic concentration follows almost exclusively the pathway ATP<=>ADP<=>AMP --> IMP --> inosine<=>hypoxanthine, with little, if any, intracellular adenosine production. At low ischemic concentration, intracellular ATP breakdown follows the pathway ATP<=>ADP<=>AMP --> adenosine --> inosine<=>hypoxanthine with little IMP formation. At the same time, extracellular ATP, whose concentration is known to be enhanced during ischemia, is actively broken down to adenosine through the pathway ATP --> ADP --> AMP --> adenosine, catalysed by the well characterized ecto-enzyme cascade system. Moreover, we show that during intracellular GTP catabolism, xanthosine, in addition to guanosine, is generated through the so called "ribose 1-phosphate recycling for nucleoside interconversion". These results considerably extend our knowledge on the long debated question of the extra or intracellular origin of adenosine in CNS, suggesting that at least in normoxic conditions, intracellular adenosine is of extracellular origin.
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Affiliation(s)
- Catia Barsotti
- Department of Physiology and Biochemistry, University of Pisa, Via San Zeno 51, 56127 Pisa, Italy.
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15
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Osorio H, Carvalho E, del Valle M, Günther Sillero MA, Moradas-Ferreira P, Sillero A. H2O2, but not menadione, provokes a decrease in the ATP and an increase in the inosine levels in Saccharomyces cerevisiae. An experimental and theoretical approach. EUROPEAN JOURNAL OF BIOCHEMISTRY 2003; 270:1578-89. [PMID: 12654013 DOI: 10.1046/j.1432-1033.2003.03529.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
When Saccharomyces cerevisiae cells, grown in galactose, glucose or mannose, were treated with 1.5 mm hydrogen peroxide (H2O2) for 30 min, an important decrease in the ATP, and a less extensive decrease in the GTP, CTP, UTP and ADP-ribose levels was estimated. Concomitantly a net increase in the inosine levels was observed. Treatment with 83 mm menadione promoted the appearance of a compound similar to adenosine but no appreciable changes in the nucleotide content of yeast cells, grown either in glucose or galactose. Changes in the specific activities of the enzymes involved in the pathway from ATP to inosine, in yeast extracts from (un)treated cells, could not explain the effect of H2O2 on the levels of ATP and inosine. Application of a mathematical model of differential equations previously developed in this laboratory pointed to a potential inhibition of glycolysis as the main reason for that effect. This theoretical consideration was reinforced both by the lack of an appreciable effect of 1.5 mm (or even higher concentrations) H2O2 on yeast grown in the presence of ethanol or glycerol, and by the observed inhibition of the synthesis of ethanol promoted by H2O2. Normal values for the adenylic charge, ATP and inosine levels were reached at 5, 30 and 120 min, respectively, after removal of H2O2 from the culture medium. The strong decrease in the ATP level upon H2O2 treatment is an important factor to be considered for understanding the response of yeast, and probably other cell types, to oxidative stress.
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Affiliation(s)
- Hugo Osorio
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas Alberto Sols UAM/CSIC, Facultad de Medicina, Madrid, Spain
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Barsotti C, Tozzi MG, Ipata PL. Purine and pyrimidine salvage in whole rat brain. Utilization of ATP-derived ribose-1-phosphate and 5-phosphoribosyl-1-pyrophosphate generated in experiments with dialyzed cell-free extracts. J Biol Chem 2002; 277:9865-9. [PMID: 11782482 DOI: 10.1074/jbc.m111418200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The object of this work stems from our previous studies on the mechanisms responsible of ribose-1-phosphate- and 5-phosphoribosyl-1-pyrophosphate-mediated nucleobase salvage and 5-fluorouracil activation in rat brain (Mascia, L., Cappiello M., Cherri, S., and Ipata, P. L. (2000) Biochim. Biophys. Acta 1474, 70-74; Mascia, L., Cotrufo, T., Cappiello, M., and Ipata, P. L. (1999) Biochim. Biophys. Acta 1472, 93-98). Here we show that when ATP at "physiological concentration" is added to dialyzed extracts of rat brain in the presence of natural nucleobases or 5-fluorouracil, adenine-, hypoxanthine-, guanine-, uracil-, and 5-fluorouracil-ribonucleotides are synthesized. The molecular mechanism of this peculiar nucleotide synthesis relies on the capacity of rat brain to salvage purine and pyrimidine bases by deriving ribose-1-phosphate and 5-phosphoribosyl-1-pyrophosphate from ATP even in the absence of added pentose or pentose phosphates. The levels of the two sugar phosphates formed are compatible with those of synthesized nucleotides. We propose that the ATP-mediated 5-phosphoribosyl-1-pyrophosphate synthesis occurs through the action of purine nucleoside phosphorylase, phosphopentomutase, and 5-phosphoribosyl-1-pyrophosphate synthetase. Furthering our previous observations on the effect of ATP in the 5-phosphoribosyl-1-pyrophosphate-mediated 5-fluorouracil activation in rat liver (Mascia, L., and Ipata, P. L. (2001) Biochem. Pharmacol. 62, 213-218), we now show that the ratio [5-phosphoribosyl-1-pyrophosphate]/[ATP] plays a major role in modulating adenine salvage in rat brain. On the basis of our in vitro results, we suggest that massive ATP degradation, as it occurs in brain during ischemia, might lead to an increase of the intracellular 5-phosphoribosyl-1-pyrophosphate and ribose-1-phosphate pools, to be utilized for nucleotide resynthesis during reperfusion.
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Affiliation(s)
- Catia Barsotti
- Department of Physiology and Biochemistry, University of Pisa, Via Santa Maria 55, 56126 Pisa, Italy
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