1
|
Tavares LC, Jarak I, Nogueira FN, Oliveira PJ, Carvalho RA. Metabolic evaluations of cancer metabolism by NMR-based stable isotope tracer methodologies. Eur J Clin Invest 2015; 45 Suppl 1:37-43. [PMID: 25524585 DOI: 10.1111/eci.12358] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND Cancer cells are widely recognized for being able to adapt their metabolism towards converting available nutrients into biomass to increase proliferation rates. MATERIALS AND METHODS We will review a series of nuclear magnetic resonance (NMR)-based stable isotope tracer methodologies for probing cancer metabolism. RESULTS The monitoring of such adaptations is of the utmost importance to unravel cancer metabolism and tumour growth. Several major metabolic targets have been recognized as promising foci and have been addressed by multiple studies in recent years. In this work are presented strategies to quantify glycolysis, pentose phosphate pathway, Krebs cycle turnover and de novo lipogenesis by NMR isotopomer analysis. CONCLUSIONS Being able to adequately define the interplay between metabolic pathways allows the monitoring of their prevalence in tissues and such information is critical for an accurate knowledge of the metabolic distinctive nature of tumours towards devising more efficient antitumorigenic strategies. Discussed methodologies are currently available in the literature, but to date, no single review has compiled all their possible uses, particularly in an interdependent perspective.
Collapse
Affiliation(s)
- Ludgero C Tavares
- Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal; Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | | | | | | | | |
Collapse
|
2
|
Sookkheo B, Phutakul S, Chen ST, Wang KT. Aspartase-Catalyzed Preparative Scale Synthesis of15N-Aspartic Acid. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.199800078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
3
|
Marin-Valencia I, Good LB, Ma Q, Jeffrey FM, Malloy CR, Pascual JM. High-resolution detection of ¹³C multiplets from the conscious mouse brain by ex vivo NMR spectroscopy. J Neurosci Methods 2011; 203:50-5. [PMID: 21946227 DOI: 10.1016/j.jneumeth.2011.09.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 08/10/2011] [Accepted: 09/07/2011] [Indexed: 10/17/2022]
Abstract
Glucose readily supplies the brain with the majority of carbon needed to sustain neurotransmitter production and utilization. The rate of brain glucose metabolism can be computed using (13)C nuclear magnetic resonance (NMR) spectroscopy by detecting changes in (13)C contents of products generated by cerebral metabolism. As previously observed, scalar coupling between adjacent (13)C carbons (multiplets) can provide additional information to (13)C contents for the computation of metabolic rates. Most NMR studies have been conducted in large animals (often under anesthesia) because the mass of the target organ is a limiting factor for NMR. Yet, despite the challengingly small size of the mouse brain, NMR studies are highly desirable because the mouse constitutes a common animal model for human neurological disorders. We have developed a method for the ex vivo resolution of NMR multiplets arising from the brain of an awake mouse after the infusion of [1,6-(13)C(2)]glucose. NMR spectra obtained by this method display favorable signal-to-noise ratios. With this infusion protocol, the (13)C multiplets of glutamate, glutamine, GABA and aspartate achieved steady state after 150 min. The method enables the accurate resolution of multiplets over time in the awake mouse brain. We anticipate that this method can be broadly applicable to compute brain fluxes in normal and transgenic mouse models of neurological disorders.
Collapse
Affiliation(s)
- Isaac Marin-Valencia
- Rare Brain Disorders Clinic and Research Laboratory, Department of Neurology and Neurotherapeutics, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | | | | | | | | | | |
Collapse
|
4
|
Parente AFA, Bailão AM, Borges CL, Parente JA, Magalhães AD, Ricart CAO, Soares CMA. Proteomic analysis reveals that iron availability alters the metabolic status of the pathogenic fungus Paracoccidioides brasiliensis. PLoS One 2011; 6:e22810. [PMID: 21829521 PMCID: PMC3145762 DOI: 10.1371/journal.pone.0022810] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 07/04/2011] [Indexed: 11/18/2022] Open
Abstract
Paracoccidioides brasiliensis is a thermodimorphic fungus and the causative agent of paracoccidioidomycosis (PCM). The ability of P. brasiliensis to uptake nutrients is fundamental for growth, but a reduction in the availability of iron and other nutrients is a host defense mechanism many pathogenic fungi must overcome. Thus, fungal mechanisms that scavenge iron from host may contribute to P. brasiliensis virulence. In order to better understand how P. brasiliensis adapts to iron starvation in the host we compared the two-dimensional (2D) gel protein profile of yeast cells during iron starvation to that of iron rich condition. Protein spots were selected for comparative analysis based on the protein staining intensity as determined by image analysis. A total of 1752 protein spots were selected for comparison, and a total of 274 out of the 1752 protein spots were determined to have changed significantly in abundance due to iron depletion. Ninety six of the 274 proteins were grouped into the following functional categories; energy, metabolism, cell rescue, virulence, cell cycle, protein synthesis, protein fate, transcription, cellular communication, and cell fate. A correlation between protein and transcript levels was also discovered using quantitative RT-PCR analysis from RNA obtained from P. brasiliensis under iron restricting conditions and from yeast cells isolated from infected mouse spleens. In addition, western blot analysis and enzyme activity assays validated the differential regulation of proteins identified by 2-D gel analysis. We observed an increase in glycolytic pathway protein regulation while tricarboxylic acid cycle, glyoxylate and methylcitrate cycles, and electron transport chain proteins decreased in abundance under iron limiting conditions. These data suggest a remodeling of P. brasiliensis metabolism by prioritizing iron independent pathways.
Collapse
Affiliation(s)
- Ana F. A. Parente
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Alexandre M. Bailão
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Clayton L. Borges
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Juliana A. Parente
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Adriana D. Magalhães
- Laboratório de Química de Proteínas, Departamento de Biologia Celular, Universidade de Brasília, Brasília, Distrito Federal, Brazil
| | - Carlos A. O. Ricart
- Laboratório de Química de Proteínas, Departamento de Biologia Celular, Universidade de Brasília, Brasília, Distrito Federal, Brazil
| | - Célia M. A. Soares
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
- * E-mail:
| |
Collapse
|
5
|
Kristiansen SB, Lfgren B, Stttrup NB, Kimose HH, Nielsen-Kudsk JE, Btker HE, Nielsen TT. CARDIOPROTECTION BY l-GLUTAMATE DURING POSTISCHAEMIC REPERFUSION: REDUCED INFARCT SIZE AND ENHANCED GLYCOGEN RESYNTHESIS IN A RAT INSULIN-FREE HEART MODEL. Clin Exp Pharmacol Physiol 2008; 35:884-8. [DOI: 10.1111/j.1440-1681.2008.04914.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
6
|
Carvalho RA, Rodrigues TB, Zhao P, Jeffrey FMH, Malloy CR, Sherry AD. A13C isotopomer kinetic analysis of cardiac metabolism: influence of altered cytosolic redox and [Ca2+]o. Am J Physiol Heart Circ Physiol 2004; 287:H889-95. [PMID: 15044195 DOI: 10.1152/ajpheart.00976.2003] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Rat hearts were perfused with mixtures of [3-(13)C]pyruvate and [3-(13)C]lactate (to alter cytosolic redox) at low (0.5 mM) or high (2.5 mM) Ca(2+) concentrations to alter contractility. Hearts were frozen at various times after exposure to these substrates, were extracted, and were then analyzed by (13)C NMR spectroscopy. The time-dependent multiplets observed in the (13)C NMR resonances of glutamate in all hearts and in malate and aspartate in hearts perfused with high-pyruvate/low-lactate concentrations were analyzed using a kinetic model of the tricarboxylic acid (TCA) cycle. The analysis showed that TCA cycle flux (V(TCA)) and exchange flux (V(X)) that involved cycle intermediates were both sensitive to cell redox and altered Ca(2+) concentration, and the ratio of these fluxes (V(X)/V(TCA)) varied >10-fold.
Collapse
Affiliation(s)
- Rui A Carvalho
- Department of Biochemistry, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal
| | | | | | | | | | | |
Collapse
|
7
|
Choi IY, Lee SP, Guilfoyle DN, Helpern JA. In vivo NMR studies of neurodegenerative diseases in transgenic and rodent models. Neurochem Res 2003; 28:987-1001. [PMID: 12737523 DOI: 10.1023/a:1023370104289] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In vivo magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) provide unique quality to attain neurochemical, physiological, anatomical, and functional information non-invasively. These techniques have been increasingly applied to biomedical research and clinical usage in diagnosis and prognosis of diseases. The ability of MRS to detect early yet subtle changes of neurochemicals in vivo permits the use of this technology for the study of cerebral metabolism in physiological and pathological conditions. Recent advances in MR technology have further extended its use to assess the etiology and progression of neurodegeneration. This review focuses on the current technical advances and the applications of MRS and MRI in the study of neurodegenerative disease animal models including amyotrophic lateral sclerosis, Alzheimer's, Huntington's, and Parkinson's diseases. Enhanced MR measurable neurochemical parameters in vivo are described in regard to their importance in neurodegenerative disorders and their investigation into the metabolic alterations accompanying the pathogenesis of neurodegeneration.
Collapse
Affiliation(s)
- In-Young Choi
- The Nathan S. Kline Institute, Center for Advanced Brain Imaging, Orangeburg, New York 10962, USA.
| | | | | | | |
Collapse
|
8
|
Ziegler A, Zaugg CE, Buser PT, Seelig J, Künnecke B. Non-invasive measurements of myocardial carbon metabolism using in vivo 13C NMR spectroscopy. NMR IN BIOMEDICINE 2002; 15:222-234. [PMID: 11968138 DOI: 10.1002/nbm.764] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Despite their prime role in maintaining contractile performance, myocardial substrate uptake, substrate preference and metabolism are difficult to assess non-invasively. The objective of the present work was to extend the scope of cardiac 13C nuclear magnetic resonance (NMR) spectroscopy to the in vivo situation ('closed-chest model') and to quantitatively appraise myocardial metabolism in vivo. For this purpose, overnight-fasted Sprague-Dawley rats received intravenous infusions of non-radioactive 13C-labeled glucose, 3-hydroxybutyrate, and acetate as markers for glycolysis, metabolism of ketone bodies and direct incorporation into tricarboxylic acid (TCA) cycle, respectively. In vivo 13C NMR spectra (at 7 T) were acquired from the myocardium with a time resolution of 6 min. At the end of the infusion experiments, tissue extracts were prepared and further analyzed by high-resolution 13C NMR spectroscopy in order to corroborate the findings obtained in vivo. Accordingly, 3-hydroxybutyrate and acetate were rapidly extracted by the myocardium and supplied 42 +/- 6 and 53 +/- 9% of the acetyl-CoA for TCA cycle operation, whereas glucose, although also well extracted, did not contribute to myocardial oxidative metabolism. Myocardial TCA cycle turnover (V(TCA)) in vivo was estimated at 1.34 +/- 0.07 micromol/min/g wet weight, myocardial oxygen consumption (MVO2) at 2.95 +/- 0.16 micromol/min/g wet weight, exchange rate between alpha-ketoglutarate and glutamate (V(x)) at 1.22 +/- 0.08 micromol/min/g wet weight and rate of glutamine synthesis (V(gln)) at 0.14 +/- 0.02 micromol/min/g wet weight. The substantial synthesis of myocardial glutamine is in contrast to experiments with isolated and saline perfused hearts. In conclusion, it is demonstrated that 13C NMR spectroscopy of the heart in intact rats is feasible and provides new quantitative insight into myocardial substrate uptake, preference and metabolism in vivo.
Collapse
Affiliation(s)
- André Ziegler
- Department of Biophysical Chemistry, Biozentrum, University of Basel, Switzerland
| | | | | | | | | |
Collapse
|
9
|
Olivson A, Berman E, Houminer E, Borman JB, Merin G, Karck M, Haverich A, Chisin R, Schwalb H. Glucose metabolism, energetics, and function of rat hearts exposed to ischemic preconditioning and oxygenated cardioplegia. J Card Surg 2002; 17:214-25. [PMID: 12489906 DOI: 10.1111/j.1540-8191.2002.tb01203.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
We examined changes induced during ischemia-reperfusion on myocardial metabolism and function by oxygenated warm cardioplegia (CP) and ischemic preconditioning (IP). The postischemic hemodynamic recovery was comparable and significantly better in IP and CP groups, than in untreated hearts (e.g., LVDP recovery was threefold that of the control). The IP hearts reached a pH plateau earlier during ischemia and at considerably higher pH value (pH approximately 6) compared to the other groups (pH approximately 5.5). Postischemic phosphocreatine (PCr) and ATP recoveries were comparable and better in protected groups (approximately 72% and approximately 30% vs approximately 25% and approximately 10% in control, p < 0.0001). Preischemic glycogen was significantly reduced in IP to 49% and increased in CP hearts to 127%. However, the lactate levels at the end of ischemia were similar in all the groups, indicating glucose utilization from extracellular space during ischemia in IP hearts. Thus, similar hemodynamic protection by CP and IP is observed despite increased energy depletion during ischemia in IP. IP and CP protection is expressed through better energetic status and by higher recovery of the TCA cycle activity or enhanced mitochondria-cytosol transport of alpha-ketoglutarate on reperfusion in addition to metabolic changes during ischemia. Glycogen store recovered significantly better in IP than in CP and Control. These results exhibit similar and improved postischemic hemodynamic protection by CP and IP. Increased recovery of postischemic glycogen pool is a protective feature of IP, whereas slightly higher lactate metabolism during reperfusion is a protection component of CP.
Collapse
Affiliation(s)
- Abira Olivson
- Human Biology Research Center, Hadassah University Hospital, Jerusalem, Israel
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
García-Martín ML, García-Espinosa MA, Ballesteros P, Bruix M, Cerdán S. Hydrogen turnover and subcellular compartmentation of hepatic [2-(13)C]glutamate and [3-(13)C]aspartate as detected by (13)C NMR. J Biol Chem 2002; 277:7799-807. [PMID: 11744718 DOI: 10.1074/jbc.m107501200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
(13)C NMR monitored the dynamics of exchange from specific hydrogens of hepatic [2-(13)C]glutamate and [3-(13)C]aspartate with deuterons from intracellular heavy water providing information on alpha-ketoglutarate/glutamate exchange and subcellular compartmentation. Mouse livers were perfused with [3-(13)C]alanine in buffer containing or not 50% (2)H(2)O for increasing periods of time (1 min < t < 30 min). Liver extracts prepared at the end of the perfusions were analyzed by high resolution (13)C NMR (150.13 MHz) with (1)H decoupling only and with simultaneous (1)H and (2)H decoupling. (13)C-(2)H couplings and (2)H-induced isotopic shifts observed in the glutamate C2 resonance, allowed to estimate the apparent rate constants (forward, reverse; min(-1)) for (i) the reversible exchange of [2-(13)C]glutamate H2 as catalyzed mainly by aspartate aminotransferase (0.32, 0.56), (ii) the reversible exchange of [2-(13)C]glutamate H3(proS) as catalyzed by NAD(P) isocitrate dehydrogenase (0.1, 0.05), and (iii) the irreversible exchanges of glutamate H3(proR) and H3(proS) as catalyzed by the sequential activities of mitochondrial aconitase and NAD isocitrate dehydrogenase of the tricarboxylic acid cycle (0.035), respectively. A similar approach allowed to determine the rates of (1)H-(2)H exchange for the H2 (0.4, 0.5) or H3(proR) (0.3, 0.2) or the H2 and H3(proS) hydrogens (0.20, 0.23) of [3-(13)C]aspartate isotopomers. The ubiquitous subcellular localization of (1)H-(2)H exchange enzymes and the exclusive mitochondrial localization of pyruvate carboxylase and the tricarboxylic acid cycle resulted in distinctive kinetics of deuteration in the H2 and either or both H3 hydrogens of [2-(13)C]glutamate and [3-(13)C]aspartate, allowing to follow glutamate and aspartate trafficking through cytosol and mitochondria.
Collapse
Affiliation(s)
- María L García-Martín
- Instituto de Investigaciones Biomédicas C.S.I.C., c/Arturo Duperier 4, E-28029 Madrid, Spain
| | | | | | | | | |
Collapse
|
11
|
Burgess SC, Babcock EE, Jeffrey FM, Sherry AD, Malloy CR. NMR indirect detection of glutamate to measure citric acid cycle flux in the isolated perfused mouse heart. FEBS Lett 2001; 505:163-7. [PMID: 11557062 DOI: 10.1016/s0014-5793(01)02799-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
(13)C-edited proton nuclear magnetic resonance (NMR) spectroscopy was used to follow enrichment of glutamate C3 and C4 with a temporal resolution of approximately 20 s in mouse hearts perfused with (13)C-enriched substrates. A fit of the NMR data to a kinetic model of the tricarboxylic acid (TCA) cycle and related exchange reactions yielded TCA cycle (V(tca)) and exchange (V(x)) fluxes between alpha-ketoglutarate and glutamate. These fluxes were substrate-dependent and decreased in the order acetate (V(tca)=14.1 micromol g(-1) min(-1); V(x)=26.5 micromol g(-1) min(-1))>octanoate (V(tca)=6.0 micromol g(-1) min(-1); V(x)=16.1 micromol g(-1) min(-1))>lactate (V(tca)=4.2 micromol g(-1) min(-1); V(x)=6.3 micromol g(-1) min(-1)).
Collapse
Affiliation(s)
- S C Burgess
- Department of Chemistry, University of Texas at Dallas, USA
| | | | | | | | | |
Collapse
|
12
|
Carvalho RA, Zhao P, Wiegers CB, Jeffrey FM, Malloy CR, Sherry AD. TCA cycle kinetics in the rat heart by analysis of (13)C isotopomers using indirect (1)H. Am J Physiol Heart Circ Physiol 2001; 281:H1413-21. [PMID: 11514314 DOI: 10.1152/ajpheart.2001.281.3.h1413] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study was designed to test the hypothesis that indirect (1)H[(13)C] detection of tricarboxylic acid (TCA) cycle intermediates using heteronuclear multiple quantum correlation-total correlation spectroscopy (HMQC-TOCSY) nuclear magnetic resonance (NMR) spectroscopy provides additional (13)C isotopomer information that better describes the kinetic exchanges that occur between intracellular compartments than direct (13)C NMR detection. NMR data were collected on extracts of rat hearts perfused at various times with combinations of [2-(13)C]acetate, propionate, the transaminase inhibitor aminooxyacetate, and (13)C multiplet areas derived from spectra of tissue glutamate were fit to a standard kinetic model of the TCA cycle. Although the two NMR methods detect different populations of (13)C isotopomers, similar values were found for TCA cycle and exchange fluxes by analyzing the two data sets. Perfusion of hearts with unlabeled propionate in addition to [2-(13)C]acetate resulted in an increase in the pool size of all four-carbon TCA cycle intermediates. This allowed the addition of isotopomer data from aspartate and malate in addition to the more abundant glutamate. This study illustrates that metabolic inhibitors can provide new insights into metabolic transport processes in intact tissues.
Collapse
Affiliation(s)
- R A Carvalho
- Mary Nell and Ralph B. Rogers Magnetic Resonance Center, Department of Radiology, University of Texas Southwestern Medical Center, Dallas 75390-9085, USA
| | | | | | | | | | | |
Collapse
|
13
|
Herve M, Buffin-Meyer B, Bouet F, Son TD. Detection of modifications in the glucose metabolism induced by genetic mutations in Saccharomyces cerevisiae by 13C- and H-NMR spectroscopy. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:3337-44. [PMID: 10824121 DOI: 10.1046/j.1432-1327.2000.01365.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
NMR spectroscopy may offer a suitable technique to characterize the glucose metabolism in response to genetic mutations in cells. The effects of various genetic modifications in Saccharomyces cerevisiae yeast were investigated using 13C- and 1H-NMR spectroscopy associated with biochemical techniques. Cells were incubated with [1-13C]glucose in order to study glucose consumption and the formation of various end-products (ethanol, trehalose, glycerol, glutamate and amino acids) as a function of time. Two types of genetic modifications were studied in S. cerevisiae. A genetic modification deleted the N-terminal part of the TFC7 protein which is the smallest subunit (tau55) of the TFIIIC transcription factor. One secondary effect of this mutation was a large deletion of mitochondrial DNA giving the rho-phenotype. The other genetic modification corresponded to the disruption of the HUF gene; the mutated cells were rho+ like the reference strain. Both mutations increase the glycolysis rate and glycerol synthesis and decrease trehalose production. The most modified cells, which contain both TFC7 deletion and HUF gene disruption, utilize glucose in the most extreme manner as in these cells the largest production of the two glycolytic products (ethanol and glycerol) and the smallest trehalose formation occur. The HUF gene disruption serves as a positive modulator of glycolysis and respiration. However, the TFC7 deletion, associated with the phenotype rho-, induces the most damage in the cellular function, dramatically altering the behaviour of the Krebs cycle. The cycle becomes blocked at the level of 2-oxoglutarate, detected by a characteristic pattern of the 13C-NMR glutamate spectra. These NMR spectra corroborate the phenotypic data, the rho-phenotype corresponding to deletions of mitochondria DNA which block all mitochondria protein synthesis and render the cells unable to derive energy from respiration. Moreover, as a consequence of the Krebs cycle blocking, alanine formation is also observed.
Collapse
Affiliation(s)
- M Herve
- Section de Biophysique des Protéines et des Membranes, Département de Biologie Cellulaire et Moléculaire, CEN Saclay, Gif-sur-Yvette, France.
| | | | | | | |
Collapse
|
14
|
Jeffrey FM, Reshetov A, Storey CJ, Carvalho RA, Sherry AD, Malloy CR. Use of a single (13)C NMR resonance of glutamate for measuring oxygen consumption in tissue. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:E1111-21. [PMID: 10600802 DOI: 10.1152/ajpendo.1999.277.6.e1111] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A kinetic model of the citric acid cycle for calculating oxygen consumption from (13)C nuclear magnetic resonance (NMR) multiplet data has been developed. Measured oxygen consumption (MVO(2)) was compared with MVO(2) predicted by the model with (13)C NMR data obtained from rat hearts perfused with glucose and either [2-(13)C]acetate or [3-(13)C]pyruvate. The accuracy of MVO(2) measured from three subsets of NMR data was compared: glutamate C-4 and C-3 resonance areas; the doublet C4D34 (expressed as a fraction of C-4 area); and C-4 and C-3 areas plus several multiplets of C-2, C-3, and C-4. MVO(2) determined by set 2 (C4D34 only) gave the same degree of accuracy as set 3 (complete data); both were superior to set 1 (C-4 and C-3 areas). Analysis of the latter suffers from the correlation between citric acid cycle flux and exchange between alpha-ketoglutarate and glutamate, resulting in greater error in estimating MVO(2). Analysis of C4D34 is less influenced by correlation between parameters, and this single measurement provides the best opportunity for a noninvasive measurement of oxygen consumption.
Collapse
Affiliation(s)
- F M Jeffrey
- Department of Radiology, The Mary Nell and Ralph B. Rogers Magnetic Resonance Center, University of Texas Southwestern Medical Center, Dallas, Texas 75235-9085, USA.
| | | | | | | | | | | |
Collapse
|
15
|
van Beek JH, van Mil HG, King RB, de Kanter FJ, Alders DJ, Bussemaker J. A (13)C NMR double-labeling method to quantitate local myocardial O(2) consumption using frozen tissue samples. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:H1630-40. [PMID: 10516204 DOI: 10.1152/ajpheart.1999.277.4.h1630] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Measurement of local myocardial O(2) consumption (VO(2)) has been problematic but is needed to investigate the heterogeneity of aerobic metabolism. The goal of the present investigation was to develop a method to measure local VO(2) using small frozen myocardial samples, suitable for determining VO(2) profiles. In 26 isolated rabbit hearts, 1.5 mmol/l [2-(13)C]acetate was infused for 4 min, followed by 1.5 min of [1,2-(13)C]acetate. The left ventricular (LV) free wall was then quickly frozen. High-resolution (13)C-NMR spectra were measured from extracts taken from 2- to 3-mm thick transmural layer samples. The multiplet intensities of glutamate were analyzed with a computer model allowing simultaneous estimation of the absolute flux through the tricarboxylic acid cycle and the fractional contribution of acetate to acetyl CoA formation from which local VO(2) was calculated. The (13)C-derived VO(2) in the LV free wall was linearly related to "gold standard" VO(2) from coronary venous O(2) electrode measurements in the same region (r = 0.932, n = 22, P < 0.0001, slope 1.05) for control and lowered metabolic rates. The ratio of subendocardial to subepicardial VO(2) was 1.52 +/- 0.19 (SE, significantly >1, P < 0.025). Local myocardial VO(2) can now be quantitated with this new (13)C method to determine profiles of aerobic energy metabolism.
Collapse
Affiliation(s)
- J H van Beek
- Laboratory for Physiology, Vrije Universiteit, 1081 BT Amsterdam, The Netherlands.
| | | | | | | | | | | |
Collapse
|
16
|
Jucker BM, Lee JY, Shulman RG. In vivo 13C NMR measurements of hepatocellular tricarboxylic acid cycle flux. J Biol Chem 1998; 273:12187-94. [PMID: 9575166 DOI: 10.1074/jbc.273.20.12187] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A combined isotopic steady state and in vivo isotopic non-steady state analysis was used to calculate tricarboxylic acid cycle flux in livers of anesthetized rats infused with ethanol. In vivo 13C NMR spectroscopy was used to non-invasively observe label turnover of [4-13C]glutamate, [4-13C]glutamine, and [2-13C]glutamate/glutamine in liver following a bolus intravenous infusion of [2-13C]ethanol. The isotopic steady state analysis of [2-13C], [3-13C], and [4-13C]glutamate isotopomers (Malloy, C. R., Sherry, A. D., and Jeffrey, F. M. H. (1988) J. Biol. Chem. 263, 6964-6971) in liver extracts was used to indirectly calculate the anaplerotic flux (0.90 +/- 0.07 x citrate synthase flux) and [2-13C]acetyl-CoA fractional enrichment (51.4 +/- 3.4%). The [4-13C]glutamate, [4-13C]glutamine, and [2-13C]glutamate fractional enrichments determined in liver extracts were 23.0 +/- 1.1, 17.2 +/- 1.5, and 7.7 +/- 0.5%, respectively. These data in addition to blood [2-13C]acetate and [4-13C]glutamine enrichment time course data were used in conjunction with a metabolic steady state mathematical analysis designed to account for liver glutamate and glutamine label dilution as a consequence of glutamine exchange with blood to calculate the tricarboxylic acid (tca) cycle flux (Vtca = 0.33 +/- 0.09 micromol/g wet weight/min) in liver. In summary, It is possible to detect 13C labeling of glutamate and glutamine in liver via non-invasive 13C NMR. Additionally, the in vivo 13C labeling kinetics of glutamate and glutamine in liver and glutamine in blood may be used to calculate the liver tricarboxylic acid cycle flux.
Collapse
Affiliation(s)
- B M Jucker
- Department of Chemistry, Yale University, New Haven, Connecticut 06510, USA
| | | | | |
Collapse
|
17
|
Sherry AD, Zhao P, Wiethoff AJ, Jeffrey FM, Malloy CR. Effects of aminooxyacetate on glutamate compartmentation and TCA cycle kinetics in rat hearts. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 274:H591-9. [PMID: 9486263 DOI: 10.1152/ajpheart.1998.274.2.h591] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The nonspecific transaminase inhibitor aminooxyacetate (AOA) has multiple influences on the dynamics of 13C appearance in glutamate in rat hearts as measured by 13C nuclear magnetic resonance (NMR) without altering O2 consumption or tricarboxylic acid (TCA) cycle flux. These include the following: 1) a reduced rate of 13C enrichment at glutamate C3 and C4; 2) a near coalescence of the C3 and C4 fractional enrichment curves; 3) a dramatic alteration in the time-dependent evolution of the glutamate C4 multiplets, C4S and C4D34; and 4) a decrease in the NMR visibility of glutamate. A fit of the 13C fractional enrichment curves of glutamate C4 and C3 in the absence of inhibitor to a kinetic model of the TCA cycle gave values for transaminase flux of 7.5 mumol.min-1.g dry wt-1 and TCA cycle flux of 7.5 mumol.min-1.g dry wt-1, thereby confirming reports by others that the kinetics of 13C enrichment of glutamate C3 and C4 in heart tissue is significantly affected by flux through reactions other than TCA cycle. The 13C fractional enrichment data collected in the presence of 0.5 mM AOA could not be fitted using this same kinetic model. However, kinetic simulations demonstrated that the time-dependent changes in C4S and C4D34 are only consistent with a 10-fold reduction in the size of intermediate pools undergoing rapid turnover in the TCA cycle. We conclude that inhibition of glutamic-oxalacetic transaminase by AOA effectively reduces the size of the alpha-ketoglutarate pool in rapid exchange with the TCA cycle. Our data indicate that changes in glutamate multiplet areas in the 13C NMR spectra of heart (as demonstrated by glutamate C4S and C4D34) are more sensitive to alterations in metabolic pool sizes in exchange with the TCA cycle than are measurements of 13C fractional enrichment at glutamate C3 and C4.
Collapse
Affiliation(s)
- A D Sherry
- Mary Nell and Ralph B. Rogers Magnetic Resonance Center, Department of Radiology, University of Texas Southwestern Medical Center, Dallas 75235-9085, USA
| | | | | | | | | |
Collapse
|
18
|
Lewandowski ED, Yu X, LaNoue KF, White LT, Doumen C, O'Donnell JM. Altered metabolite exchange between subcellular compartments in intact postischemic rabbit hearts. Circ Res 1997; 81:165-75. [PMID: 9242177 DOI: 10.1161/01.res.81.2.165] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
To examine metabolic regulation in postischemic hearts, we examined oxidative recycling of 13C within the glutamate pool (GLU) of intact rabbit hearts. Isolated hearts oxidized 2.5 mmol/L [2-13C]acetate during normal conditions (n = 6) or during reperfusion after 10 minutes of ischemia (n = 5). 13C-Nuclear magnetic resonance spectra were acquired every 1 minute. Kinetic analysis of 13C incorporation into GLU provided both tricarboxylic acid (TCA) cycle flux and the interconversion rate (F1) between the TCA cycle intermediate, alpha-ketoglutarate (alpha-KG), and the largely cytosolic GLU. The rate-pressure product in postischemic hearts was 46% of normal (P < .05). No difference in substrate utilization occurred between groups, with acetate accounting for 92% of the carbon units entering the TCA cycle at the citrate synthase step. TCA cycle flux in postischemic hearts was normal (normal hearts, 10.7 mumol.min-1.g-1; postischemic hearts, 9.4 mumol.min-1.g-1), whereas F1 was 72% lower at 2.9 +/- 0.4 versus 10.2 +/- 2.5 mumol.min-1.g-1 (mean +/- SE) in normal hearts (P < .05). From additional hearts perfused with 2.5 mmol/L [2-13C]acetate plus supplemental 5 mmol/L glucose, any potential differences in endogenous carbohydrate availability were proved not to account for the reduced rate alpha-KG and GLU exchange, which remained depressed in postischemic hearts. However, specific activities of the transaminase enzyme, catalyzing chemical exchange of alpha-KG and GLU, were the same, and transaminase flux was 100 mumol.min-1.g-1 in postischemic hearts versus 68 mumol.min-1.g-1 in normal hearts. Normal transaminase activity and the increased flux in postischemic hearts are contrary to the reduced F1. The findings indicate reduced metabolite transport rates across the mitochondrial membranes of stunned myocardium, particularly through the reversible alpha-KG-malate carrier.
Collapse
Affiliation(s)
- E D Lewandowski
- NMR Center, Massachusetts General Hospital, Charlestown, USA.
| | | | | | | | | | | |
Collapse
|
19
|
Wei H, Merkle H, Xu Y, Ellermann J, Sipprell K, Uğurbil K. Detection of 13C-labeled metabolites in the in vivo canine heart by B1 insensitive heteronuclear coherent polarization transfer and comparison of signal enhancement with NOE. Magn Reson Med 1997; 37:327-30. [PMID: 9055219 DOI: 10.1002/mrm.1910370303] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A recently developed adiabatic coherent polarization transfer enhancement technique [H. Merkle, H. Wei, M. Garwood, K. Uğurbil. J. Magn. Reson, 99, 480-494 (1992)] was employed to perform 13C spectroscopy in the intact canine heart in vivo during [2-13C]-acetate infusion into the left descending coronary artery, the results were compared with 13C spectra obtained with conventionally employed nuclear Overhauser enhancement. The results demonstrate that both methods can be performed by using surface coils to obtain in vivo 13C spectra and that coherent polarization transfer provides better enhancement than NOE for [2-13C]-acetate but not for short T2 compounds.
Collapse
Affiliation(s)
- H Wei
- Department of Radiology, University of Minnesota Medical School, Minneapolis 55455, USA
| | | | | | | | | | | |
Collapse
|
20
|
Szczepaniak L, Babcock EE, Malloy CR, Sherry AD. Oxidation of acetate in rabbit skeletal muscle: detection by 13C NMR spectroscopy in vivo. Magn Reson Med 1996; 36:451-7. [PMID: 8875417 DOI: 10.1002/mrm.1910360318] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The results of a proton-decoupled and Overhauser-enhanced 13C NMR study of acetate metabolism in skeletal muscle are reported. [2-13C]Acetate was infused intravenously over 2 h into anesthetized rabbits, and skeletal muscle in the lateral thigh was monitored by 13C NMR spectroscopy at 4.7 T. Stable 13C enrichment in carbons 2, 3, and 4 of glutamate was observed at the end of the infusion, and the half-time for enrichment was 17 min for glutamate C4 and 50 min for glutamate C2 and C3. The contribution of exogenous acetate to acetylcoenzyme A was nearly equal in skeletal muscle and heart in vivo (83-87%, measured in tissue extracts), comparable with earlier perfused heart studies in which acetate was the sole available substrate. Although relative flux through the combined anaplerotic pathways (relative to citric acid cycle flux) was higher in quiescent skeletal muscle (28%) compared with hearts (3%) from the same animals, actual anaplerotic flux was estimated to be substantially higher in heart than in skeletal muscle after correcting for differences in citric acid cycle flux in the two tissues.
Collapse
Affiliation(s)
- L Szczepaniak
- Department of Radiology, Mary Nell and Ralph B. Rogers Magnetic Resonance Center, University of Texas Southwestern Medical Center, Dallas, USA
| | | | | | | |
Collapse
|
21
|
Yu X, White LT, Doumen C, Damico LA, LaNoue KF, Alpert NM, Lewandowski ED. Kinetic analysis of dynamic 13C NMR spectra: metabolic flux, regulation, and compartmentation in hearts. Biophys J 1995; 69:2090-102. [PMID: 8580353 PMCID: PMC1236443 DOI: 10.1016/s0006-3495(95)80080-9] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Control of oxidative metabolism was studied using 13C NMR spectroscopy to detect rate-limiting steps in 13C labeling of glutamate. 13C NMR spectra were acquired every 1 or 2 min from isolated rabbit hearts perfused with either 2.5 mM [2-13C]acetate or 2.5 mM [2-13C]butyrate with or without KCl arrest. Tricarboxylic acid cycle flux (VTCA) and the exchange rate between alpha-ketoglutarate and glutamate (F1) were determined by least-square fitting of a kinetic model to NMR data. Rates were compared to measured kinetics of the cardiac glutamate-oxaloacetate transaminase (GOT). Despite similar oxygen use, hearts oxidizing butyrate instead of acetate showed delayed incorporation of 13C label into glutamate and lower VTCA, because of the influence of beta-oxidation: butyrate = 7.1 +/- 0.2 mumol/min/g dry wt; acetate = 10.1 +/- 0.2; butyrate + KCl = 1.8 +/- 0.1; acetate + KCl = 3.1 +/- 0.1 (mean +/- SD). F1 ranged from a low of 4.4 +/- 1.0 mumol/min/g (butyrate + KCl) to 9.3 +/- 0.6 (acetate), at least 20-fold slower than GOT flux, and proved to be rate limiting for isotope turnover in the glutamate pool. Therefore, dynamic 13C NMR observations were sensitive not only to TCA cycle flux but also to the interconversion between TCA cycle intermediates and glutamate.
Collapse
Affiliation(s)
- X Yu
- NMR Center, Massachusetts General Hospital, Boston, USA
| | | | | | | | | | | | | |
Collapse
|