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Peng Y, Zhang Z, He L, Li C, Liu M. NMR spectroscopy for metabolomics in the living system: recent progress and future challenges. Anal Bioanal Chem 2024; 416:2319-2334. [PMID: 38240793 PMCID: PMC10950998 DOI: 10.1007/s00216-024-05137-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 12/08/2023] [Accepted: 01/10/2024] [Indexed: 03/21/2024]
Abstract
Metabolism is a fundamental process that underlies human health and diseases. Nuclear magnetic resonance (NMR) techniques offer a powerful approach to identify metabolic processes and track the flux of metabolites at the molecular level in living systems. An in vitro study through in-cell NMR tracks metabolites in real time and investigates protein structures and dynamics in a state close to their most natural environment. This technique characterizes metabolites and proteins involved in metabolic pathways in prokaryotic and eukaryotic cells. In vivo magnetic resonance spectroscopy (MRS) enables whole-organism metabolic monitoring by visualizing the spatial distribution of metabolites and targeted proteins. One limitation of these NMR techniques is the sensitivity, for which a possible improved approach is through isotopic enrichment or hyperpolarization methods, including dynamic nuclear polarization (DNP) and parahydrogen-induced polarization (PHIP). DNP involves the transfer of high polarization from electronic spins of radicals to surrounding nuclear spins for signal enhancements, allowing the detection of low-abundance metabolites and real-time monitoring of metabolic activities. PHIP enables the transfer of nuclear spin polarization from parahydrogen to other nuclei for signal enhancements, particularly in proton NMR, and has been applied in studies of enzymatic reactions and cell signaling. This review provides an overview of in-cell NMR, in vivo MRS, and hyperpolarization techniques, highlighting their applications in metabolic studies and discussing challenges and future perspectives.
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Affiliation(s)
- Yun Peng
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Zeting Zhang
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Lichun He
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Conggang Li
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Maili Liu
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, China.
- Optics Valley Laboratory, Wuhan, 430074, Hubei, China.
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Nagana Gowda GA, Lusk JA, Pascua V. Intracellular pyruvate-lactate-alanine cycling detected using real-time nuclear magnetic resonance spectroscopy of live cells and isolated mitochondria. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2024; 62:84-93. [PMID: 38098198 PMCID: PMC10872489 DOI: 10.1002/mrc.5419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 11/07/2023] [Accepted: 11/16/2023] [Indexed: 01/13/2024]
Abstract
Pyruvate, an end product of glycolysis, is a master fuel for cellular energy. A portion of cytosolic pyruvate is transported into mitochondria, while the remaining portion is converted reversibly into lactate and alanine. It is suggested that cytosolic lactate and alanine are transported and metabolized inside mitochondria. However, such a mechanism continues to be a topic of intense debate and investigation. As a part of gaining insight into the metabolic fate of the cytosolic lactate and alanine; in this study, the metabolism of mouse skeletal myoblast cells (C2C12) and their isolated mitochondria was probed utilizing stable isotope-labeled forms of the three glycolysis products, viz. [3-13 C1 ]pyruvate, [3-13 C1 ]lactate, and [3-13 C1 ]alanine, as substrates. The uptake and metabolism of each substrate was monitored, separately, in real-time using 1 H-13 C 2D nuclear magnetic resonance (NMR) spectroscopy. The dynamic variation of the levels of the substrates and their metabolic products were quantitated as a function of time. The results demonstrate that all three substrates were transported into mitochondria, and each substrate was metabolized to form the other two metabolites, reversibly. These results provide direct evidence for intracellular pyruvate-lactate-alanine cycling, in which lactate and alanine produced by the cytosolic pyruvate are transported into mitochondria and converted back to pyruvate. Such a mechanism suggests a role for lactate and alanine to replenish mitochondrial pyruvate, the primary source for adenosine triphosphate (ATP) synthesis through oxidative phosphorylation and the electron transport chain. The results highlight the potential of real-time NMR spectroscopy for gaining new insights into cellular and subcellular functions.
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Affiliation(s)
- G. A. Nagana Gowda
- Northwest Metabolomics Research Center, Mitochondria and Metabolism Center, Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington 98109, USA
| | - John A. Lusk
- Northwest Metabolomics Research Center, Mitochondria and Metabolism Center, Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Vadim Pascua
- Northwest Metabolomics Research Center, Mitochondria and Metabolism Center, Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington 98109, USA
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Nagana Gowda GA, Pascua V, Lusk JA, Hong NN, Guo L, Dong J, Sweet IR, Raftery D. Monitoring live mitochondrial metabolism in real-time using NMR spectroscopy. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2023; 61:718-727. [PMID: 36882950 PMCID: PMC10483017 DOI: 10.1002/mrc.5341] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 02/03/2023] [Accepted: 03/03/2023] [Indexed: 06/18/2023]
Abstract
Investigation of mitochondrial metabolism is gaining increased interest owing to the growing recognition of the role of mitochondria in health and numerous diseases. Studies of isolated mitochondria promise novel insights into the metabolism devoid of confounding effects from other cellular organelles such as cytoplasm. This study describes the isolation of mitochondria from mouse skeletal myoblast cells (C2C12) and the investigation of live mitochondrial metabolism in real-time using isotope tracer-based NMR spectroscopy. [3-13 C1 ]pyruvate was used as the substrate to monitor the dynamic changes of the downstream metabolites in mitochondria. The results demonstrate an intriguing phenomenon, in which lactate is produced from pyruvate inside the mitochondria and the results were confirmed by treating mitochondria with an inhibitor of mitochondrial pyruvate carrier (UK5099). Lactate is associated with health and numerous diseases including cancer and, to date, it is known to occur only in the cytoplasm. The insight that lactate is also produced inside mitochondria opens avenues for exploring new pathways of lactate metabolism. Further, experiments performed using inhibitors of the mitochondrial respiratory chain, FCCP and rotenone, show that [2-13 C1 ]acetyl coenzyme A, which is produced from [3-13 C1 ]pyruvate and acts as a primary substrate for the tricarboxylic acid cycle in mitochondria, exhibits a remarkable sensitivity to the inhibitors. These results offer a direct approach to visualize mitochondrial respiration through altered levels of the associated metabolites.
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Affiliation(s)
- G. A. Nagana Gowda
- Northwest Metabolomics Research Center, Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington 98109, USA
- Mitochondria and Metabolism Center, Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Vadim Pascua
- Northwest Metabolomics Research Center, Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington 98109, USA
- Mitochondria and Metabolism Center, Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington 98109, USA
| | - John A. Lusk
- Northwest Metabolomics Research Center, Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington 98109, USA
- Mitochondria and Metabolism Center, Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Natalie N. Hong
- Northwest Metabolomics Research Center, Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington 98109, USA
- Mitochondria and Metabolism Center, Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Lin Guo
- Northwest Metabolomics Research Center, Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Jiyang Dong
- Northwest Metabolomics Research Center, Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington 98109, USA
- Department of Electronic Science, Xiamen University, Xiamen 361005, China
| | - Ian R. Sweet
- Department of Medicine, University of Washington, Seattle, Washington 98109, USA
| | - Daniel Raftery
- Northwest Metabolomics Research Center, Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington 98109, USA
- Mitochondria and Metabolism Center, Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington 98109, USA
- Fred Hutchinson Cancer Center, Seattle, Washington 98109, USA
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Observation of acetyl phosphate formation in mammalian mitochondria using real-time in-organelle NMR metabolomics. Proc Natl Acad Sci U S A 2018; 115:4152-4157. [PMID: 29610354 DOI: 10.1073/pnas.1720908115] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recent studies point out the link between altered mitochondrial metabolism and cancer, and detailed understanding of mitochondrial metabolism requires real-time detection of its metabolites. Employing heteronuclear 2D NMR spectroscopy and 13C3-pyruvate, we propose in-organelle metabolomics that allows for the monitoring of mitochondrial metabolic changes in real time. The approach identified acetyl phosphate from human mitochondria, whose production has been largely neglected in eukaryotic metabolism since its first description about 70 years ago in bacteria. The kinetic profile of acetyl phosphate formation was biphasic, and its transient nature suggested its role as a metabolic intermediate. The method also allowed for the estimation of pyruvate dehydrogenase (PDH) enzyme activity through monitoring of the acetyl-CoA formation, independent of competing cytosolic metabolism. The results confirmed the positive regulation of mitochondrial PDH activity by p53, a well-known tumor suppressor. Our approach can easily be applied to other organelle-specific metabolic studies.
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Solinas P, Fujioka H, Tandler B, Hoppel CL. Isolation of rat adrenocortical mitochondria. Biochem Biophys Res Commun 2012; 427:96-9. [PMID: 22982630 DOI: 10.1016/j.bbrc.2012.09.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 09/02/2012] [Indexed: 11/16/2022]
Abstract
This report describes a relatively simple and reliable method for isolating adrenocortical mitochondria from rats in good, reasonably pure yield. These organelles, which heretofore have been unobtainable in isolated form from small laboratory animals, are now readily accessible. A high degree of mitochondrial purity is shown by the electron micrographs, as well as the structural integrity of each mitochondrion. That these organelles have retained their functional integrity is shown by their high respiratory control ratios. In general, the biochemical performance of these adrenal cortical mitochondria closely mirrors that of typical hepatic or cardiac mitochondria.
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Affiliation(s)
- Paola Solinas
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
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Zahavi A, Perel M. The information encoded by the sex steroid hormones testosterone and estrogen: a hypothesis. J Theor Biol 2011; 280:146-9. [PMID: 21530548 DOI: 10.1016/j.jtbi.2011.04.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 12/31/2010] [Accepted: 04/12/2011] [Indexed: 10/18/2022]
Abstract
It is suggested that the sex steroid hormones testosterone and estrogen (SSH) provide receptor cells with reliable information on protein synthesis and on the level of oxidative metabolism in the cells of the gonads. The SSH are derived from the oxidation of cholesterol. This oxidation is a side reaction of the oxidative processes in the mitochondria that generate most of the energy to the organism. The amount of SSH that is synthesized is correlated to the partial pressure of oxygen at the synthesizing cells. The amount of free SSH that a cell can hold is checked by the damage that free steroids may cause. This damage is prevented by proteins that bind with SSH. As a result, SSH levels are correlated also with the ability of the SSH synthesizing cell to produce proteins that bind with them. A cell can only synthesize SSH in relation to the oxidative processes within it and to its ability to produce the binding proteins necessary to prevent the damage caused by SSH. As a result, the information conveyed by SSH is reliable. We examine the specific damage caused by testosterone and estrogen, and suggest why each of them is best suited for its function. Although both SSH can provide similar information on the metabolism in the cells that synthesize them, there are secondary reasons why testosterone and estrogen were selected to serve particular functions. Testosterone improves the efficiency of the proton pump at the mitochondria in producing ATP, but increases oxidative damage. Estrogen on the other hand decreases oxygen damage but also decreases the efficiency of the proton pump. These differences between the two SSH may explain why females use estrogen to inform the body about the activity of the cells in their gonads while males do it by testosterone. The increased oxidative damage may also explain why in males the testosterone that reaches the brain is turned into estrogen. We also suggest why fish use 11-keto testosterone and why insects do not use these two steroids.
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Affiliation(s)
- Amotz Zahavi
- Dept. of Zoology, Tel-Aviv University, Tel-Aviv, Israel.
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Perrin A, Roudier E, Duborjal H, Bachelet C, Riva-Lavieille C, Leverve X, Massarelli R. Pyruvate reverses metabolic effects produced by hypoxia in glioma and hepatoma cell cultures. Biochimie 2002; 84:1003-11. [PMID: 12504280 DOI: 10.1016/s0300-9084(02)00008-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The intervention of pyruvate in glucose metabolism was investigated during hypoxic stress in tumour cell cultures having respiratory capacities under normoxic conditions. Results obtained with nuclear magnetic resonance (NMR) spectroscopy showed that, under normoxic conditions, rat glioma C6 and human hepatoma Hep G2 cell cultures metabolised [(13)C(1)]glucose into lactate, alanine, glutamate and other less abundant metabolites, as already known from the literature. In the absence of pyruvate, during hypoxia or cyanide poisoning, both cell types dramatically decreased the label into glutamate and accumulated [(13)C(3)]glycerol-3-phosphate. The compound was further identified by 31P NMR spectroscopy. The accumulation of the label in glycerol-3-phosphate, however, did not occur when the cells were incubated in the presence of pyruvate. The fate of the latter, followed under normoxic conditions by incubating cells with [(13)C(3)]pyruvate and natural glucose, showed that the label was mainly found in alanine, lactate and glutamate. Anoxic conditions increased the label in lactate and reduced that of glutamate. The data show a metabolic effect of pyruvate during mitochondrial blockade due to severe lack of oxygen in tumour cell lines.
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Affiliation(s)
- Anne Perrin
- Unité de biophysique, CRSSA, BP 87, 38702 La Tronche cedex, France
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