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Ramirez-Hincapie S, Giri V, Keller J, Kamp H, Haake V, Richling E, van Ravenzwaay B. Influence of pregnancy and non-fasting conditions on the plasma metabolome in a rat prenatal toxicity study. Arch Toxicol 2021; 95:2941-2959. [PMID: 34327559 DOI: 10.1007/s00204-021-03105-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 06/17/2021] [Indexed: 11/25/2022]
Abstract
The current parameters for determining maternal toxicity (e.g. clinical signs, food consumption, body weight development) lack specificity and may underestimate the extent of effects of test compounds on the dams. Previous reports have highlighted the use of plasma metabolomics for an improved and mechanism-based identification of maternal toxicity. To establish metabolite profiles of healthy pregnancies and evaluate the influence of food consumption as a confounding factor, metabolite profiling of rat plasma was performed by gas- and liquid-chromatography-tandem mass spectrometry techniques. Metabolite changes in response to pregnancy, food consumption prior to blood sampling (non-fasting) as well as the interaction of both conditions were studied. In dams, both conditions, non-fasting and pregnancy, had a marked influence on the plasma metabolome and resulted in distinct individual patterns of changed metabolites. Non-fasting was characterized by increased plasma concentrations of amino acids and diet related compounds and lower levels of ketone bodies. The metabolic profile of pregnant rats was characterized by lower amino acids and glucose levels and higher concentrations of plasma fatty acids, triglycerides and hormones, capturing the normal biochemical changes undergone during pregnancy. The establishment of metabolic profiles of pregnant non-fasted rats serves as a baseline to create metabolic fingerprints for prenatal and maternal toxicity studies.
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Affiliation(s)
- S Ramirez-Hincapie
- Experimental Toxicology and Ecology, BASF SE, 67056, Ludwigshafen, Germany
| | - V Giri
- Experimental Toxicology and Ecology, BASF SE, 67056, Ludwigshafen, Germany
| | - J Keller
- Experimental Toxicology and Ecology, BASF SE, 67056, Ludwigshafen, Germany
| | - H Kamp
- Experimental Toxicology and Ecology, BASF SE, 67056, Ludwigshafen, Germany
| | - V Haake
- BASF Metabolome Solution GmbH, Berlin, Germany
| | - E Richling
- Food Chemistry and Toxicology, Department of Chemistry, University of Kaiserslautern, Kaiserslautern, Germany
| | - B van Ravenzwaay
- Experimental Toxicology and Ecology, BASF SE, 67056, Ludwigshafen, Germany.
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Coleman PS, Parlo RA. Warburg's Ghost-Cancer's Self-Sustaining Phenotype: The Aberrant Carbon Flux in Cholesterol-Enriched Tumor Mitochondria via Deregulated Cholesterogenesis. Front Cell Dev Biol 2021; 9:626316. [PMID: 33777935 PMCID: PMC7994618 DOI: 10.3389/fcell.2021.626316] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 01/29/2021] [Indexed: 01/08/2023] Open
Abstract
Interpreting connections between the multiple networks of cell metabolism is indispensable for understanding how cells maintain homeostasis or transform into the decontrolled proliferation phenotype of cancer. Situated at a critical metabolic intersection, citrate, derived via glycolysis, serves as either a combustible fuel for aerobic mitochondrial bioenergetics or as a continuously replenished cytosolic carbon source for lipid biosynthesis, an essentially anaerobic process. Therein lies the paradox: under what conditions do cells control the metabolic route by which they process citrate? The Warburg effect exposes essentially the same dilemma—why do cancer cells, despite an abundance of oxygen needed for energy-generating mitochondrial respiration with citrate as fuel, avoid catabolizing mitochondrial citrate and instead rely upon accelerated glycolysis to support their energy requirements? This review details the genesis and consequences of the metabolic paradigm of a “truncated” Krebs/TCA cycle. Abundant data are presented for substrate utilization and membrane cholesterol enrichment in tumors that are consistent with criteria of the Warburg effect. From healthy cellular homeostasis to the uncontrolled proliferation of tumors, metabolic alterations center upon the loss of regulation of the cholesterol biosynthetic pathway. Deregulated tumor cholesterogenesis at the HMGR locus, generating enhanced carbon flux through the cholesterol synthesis pathway, is an absolute prerequisite for DNA synthesis and cell division. Therefore, expedited citrate efflux from cholesterol-enriched tumor mitochondria via the CTP/SLC25A1 citrate transporter is fundamental for sustaining the constant demand for cytosolic citrate that fuels the elevated flow of carbons from acetyl-CoA through the deregulated pathway of cholesterol biosynthesis.
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Affiliation(s)
| | - Risa A Parlo
- Kingsborough Community College, Brooklyn, NY, United States
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Li Z, Erion DM, Maurer TS. Model-Based Assessment of Plasma Citrate Flux Into the Liver: Implications for NaCT as a Therapeutic Target. CPT-PHARMACOMETRICS & SYSTEMS PHARMACOLOGY 2016; 5:132-9. [PMID: 27069776 PMCID: PMC4809623 DOI: 10.1002/psp4.12062] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 01/25/2016] [Indexed: 12/26/2022]
Abstract
Cytoplasmic citrate serves as an important regulator of gluconeogenesis and carbon source for de novo lipogenesis in the liver. For this reason, the sodium-coupled citrate transporter (NaCT), a plasma membrane transporter that governs hepatic influx of plasma citrate in human, is being explored as a potential therapeutic target for metabolic disorders. As cytoplasmic citrate also originates from intracellular mitochondria, the relative contribution of these two pathways represents critical information necessary to underwrite confidence in this target. In this work, hepatic influx of plasma citrate was quantified via pharmacokinetic modeling of published clinical data. The influx was then compared to independent literature estimates of intracellular citrate flux in human liver. The results indicate that, under normal conditions, <10% of hepatic citrate originates from plasma. Similar estimates were determined experimentally in mice and rats. This suggests that NaCT inhibition will have a limited impact on hepatic citrate concentrations across species.
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Affiliation(s)
- Z Li
- Systems Modeling and Simulation Pharmacokinetics, Pharmacodynamics, and Metabolism, Pfizer Global Research and Development Cambridge Massachusetts USA
| | - D M Erion
- Cardiovascular, Metabolic & Endocrine Disease Research Unit Cambridge Massachusetts USA
| | - T S Maurer
- Systems Modeling and Simulation Pharmacokinetics, Pharmacodynamics, and Metabolism, Pfizer Global Research and Development Cambridge Massachusetts USA
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Zu X, Zhong J, Luo D, Tan J, Zhang Q, Wu Y, Liu J, Cao R, Wen G, Cao D. Chemical genetics of acetyl-CoA carboxylases. Molecules 2013; 18:1704-19. [PMID: 23358327 PMCID: PMC6269866 DOI: 10.3390/molecules18021704] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 01/03/2013] [Accepted: 01/11/2013] [Indexed: 12/16/2022] Open
Abstract
Chemical genetic studies on acetyl-CoA carboxylases (ACCs), rate-limiting enzymes in long chain fatty acid biosynthesis, have greatly advanced the understanding of their biochemistry and molecular biology and promoted the use of ACCs as targets for herbicides in agriculture and for development of drugs for diabetes, obesity and cancers. In mammals, ACCs have both biotin carboxylase (BC) and carboxyltransferase (CT) activity, catalyzing carboxylation of acetyl-CoA to malonyl-CoA. Several classes of small chemicals modulate ACC activity, including cellular metabolites, natural compounds, and chemically synthesized products. This article reviews chemical genetic studies of ACCs and the use of ACCs for targeted therapy of cancers.
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Affiliation(s)
- Xuyu Zu
- Institute of Clinical Medicine, the First Affiliated Hospital, University of South China, Hengyang 421001, Hunan, China
| | - Jing Zhong
- Institute of Clinical Medicine, the First Affiliated Hospital, University of South China, Hengyang 421001, Hunan, China
| | - Dixian Luo
- Institute of Translational Medicine & Department of Laboratory Medicine, the First People’s Hospital of Chenzhou, 102 Luojiajing Road, Chenzhou 423000, Hunan, China
| | - Jingjing Tan
- Institute of Clinical Medicine, the First Affiliated Hospital, University of South China, Hengyang 421001, Hunan, China
| | - Qinghai Zhang
- Institute of Clinical Medicine, the First Affiliated Hospital, University of South China, Hengyang 421001, Hunan, China
| | - Ying Wu
- Institute of Clinical Medicine, the First Affiliated Hospital, University of South China, Hengyang 421001, Hunan, China
| | - Jianghua Liu
- Institute of Clinical Medicine, the First Affiliated Hospital, University of South China, Hengyang 421001, Hunan, China
| | - Renxian Cao
- Institute of Clinical Medicine, the First Affiliated Hospital, University of South China, Hengyang 421001, Hunan, China
- Authors to whom correspondence should be addressed; E-Mails: (R.C.); (D.C.); Tel.: +86-217-545-9703 (D.C.); Fax: +86-217-545-9718 (D.C.)
| | - Gebo Wen
- Institute of Clinical Medicine, the First Affiliated Hospital, University of South China, Hengyang 421001, Hunan, China
| | - Deliang Cao
- Department of Microbiology, Immunology and Cell Biology, Simmons Cancer Institute, Southern Illinois University School of Medicine, 913 N. Rutledge Street, Springfield, IL 62794, USA
- Authors to whom correspondence should be addressed; E-Mails: (R.C.); (D.C.); Tel.: +86-217-545-9703 (D.C.); Fax: +86-217-545-9718 (D.C.)
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Kleiber N, Chessex P, Rouleau T, Nuyt AM, Perreault M, Lavoie JC. Neonatal exposure to oxidants induces later in life a metabolic response associated to a phenotype of energy deficiency in an animal model of total parenteral nutrition. Pediatr Res 2010; 68:188-92. [PMID: 20543762 DOI: 10.1203/pdr.0b013e3181ebb541] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Failure to protect total parenteral nutrition (TPN) from ambient light exacerbates the generation of peroxides, which affects blood glucose and plasma triacylglyceride (TG) in neonates. Based on the concept that the origin of adult diseases can be traced back to perinatal life, it was hypothesized that neonatal exposure to peroxides may affect energy availability later in life. Three-day-old guinea pigs, fitted with a jugular catheter, were fed regular chow (sham) +/- i.v. 350 microM H2O2 (sham + H2O2) or nourished with light-protected TPN [TPN(-)L, 209 +/- 9 microM peroxides] or light-exposed TPN [TPN(+)L, 365 +/- 15 microM peroxides]. After 4 d, infusions were stopped and animals fed chow. Spontaneous ambulatory movements, fasting blood glucose, glucose tolerance, TG, hepatic activities of glucokinase, phosphofructokinase (key enzymes of glycolysis), and acetyl-CoA carboxylase (key enzymes of lipogenesis) were determined at 12-14 wk and compared by ANOVA (p < 0.05). Relative to sham, the animals from sham + H2O2, TPN(-)L and TPN(+)L groups had lower plasma TG explained for 36% by low phosphofructokinase activity; they had lower glucose tolerance, lower body weight, and lower physical activity. In conclusion, neonatal exposure to oxidant molecules such as peroxides has important consequences later in life on lipid and glucose metabolism leading to a phenotype of energy deficiency.
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Affiliation(s)
- Niina Kleiber
- Department of Pediatrics, CHU Sainte-Justine, University of Montréal, 3175 Chemin de la Côte Ste-Catherine, Montréal, Québec, Canada
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Sweet IR, Gilbert M, Maloney E, Hockenbery DM, Schwartz MW, Kim F. Endothelial inflammation induced by excess glucose is associated with cytosolic glucose 6-phosphate but not increased mitochondrial respiration. Diabetologia 2009; 52:921-31. [PMID: 19219423 PMCID: PMC2741088 DOI: 10.1007/s00125-009-1272-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Accepted: 01/08/2009] [Indexed: 10/21/2022]
Abstract
AIMS/HYPOTHESIS Exposure of endothelial cells to high glucose levels suppresses responses to insulin, including induction of endothelial nitric oxide synthase activity, through pro-inflammatory signalling via the inhibitor of nuclear factor kappaB (IkappaB)alpha-nuclear factor kappaB (NF-kappaB) pathway. In the current study, we aimed to identify metabolic responses to glucose excess that mediate endothelial cell inflammation and insulin resistance. Since endothelial cells decrease their oxygen consumption rate (OCR) in response to glucose, we hypothesised that increased mitochondrial function would not mediate these cells' response to excess substrate. METHODS The effects of glycolytic and mitochondrial fuels on metabolic intermediates and end-products of glycolytic and oxidative metabolism, including glucose 6-phosphate (G6P), lactate, CO(2), NAD(P)H and OCR, were measured in cultured human microvascular endothelial cells and correlated with IkappaBalpha phosphorylation. RESULTS In response to increases in glucose concentration from low to physiological levels (0-5 mmol/l), production of G6P, lactate, NAD(P)H and CO(2) each increased as expected, while OCR was sharply reduced. IkappaBalpha activation was detected at glucose concentrations >5 mmol/l, which was associated with parallel increases of G6P levels, whereas downstream metabolic pathways were insensitive to excess substrate. CONCLUSIONS/INTERPRETATION Phosphorylation of IkappaBalpha by excess glucose correlates with increased levels of the glycolytic intermediate G6P, but not with lactate generation or OCR, which are inhibited well below saturation levels at physiological glucose concentrations. These findings suggest that oxidative stress due to increased mitochondrial respiration is unlikely to mediate endothelial inflammation induced by excess glucose and suggests instead the involvement of G6P accumulation in the adverse effects of hyperglycaemia on endothelial cells.
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Affiliation(s)
- I R Sweet
- Department of Medicine, Diabetes and Obesity Center of Excellence, University of Washington at South Lake Union, Seattle, Washington 98195-8055, USA.
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Atlante A, Giannattasio S, Bobba A, Gagliardi S, Petragallo V, Calissano P, Marra E, Passarella S. An increase in the ATP levels occurs in cerebellar granule cells en route to apoptosis in which ATP derives from both oxidative phosphorylation and anaerobic glycolysis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2005; 1708:50-62. [PMID: 15949983 DOI: 10.1016/j.bbabio.2005.01.009] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2004] [Revised: 12/13/2004] [Accepted: 01/21/2005] [Indexed: 11/28/2022]
Abstract
Although it is recognized that ATP plays a part in apoptosis, whether and how its level changes en route to apoptosis as well as how ATP is synthesized has not been fully investigated. We have addressed these questions using cultured cerebellar granule cells. In particular, we measured the content of ATP, ADP, AMP, IMP, inosine, adenosine and L-lactate in cells undergoing apoptosis during the commitment phase (0-8 h) in the absence or presence of oligomycin or/and of citrate, which can inhibit totally the mitochondrial oxidative phosphorylation and largely the substrate-level phosphorylation in glycolysis, respectively. In the absence of inhibitors, apoptosis was accompanied by an increase in ATP and a decrease in ADP with 1:1 stoichiometry, with maximum ATP level found at 3 h apoptosis, but with no change in levels of AMP and its breakdown products and with a relatively low level of L-lactate production. Consistently, there was an increase in the cell energy charge and in the ratio ([ATP][AMP])/[ADP](2). When the oxidative phosphorylation was completely blocked by oligomycin, a decrease of the ATP content was found both in control cells and in cells undergoing apoptosis, but nonetheless cells still died by apoptosis, as shown by checking DNA laddering and by death prevention due to actinomycin D. In this case, ATP was provided by anaerobic glycolysis, as suggested by the large increase of L-lactate production. On the other hand, citrate itself caused a small decrease in ATP level together with a huge decrease in L-lactate production, but it had no effect on cell survival. When ATP level was further decreased due to the presence of both oligomycin and citrate, death occurred via necrosis at 8 h, as shown by the lack of DNA laddering and by death prevention found due to the NMDA receptor antagonist MK801. However, at a longer time, when ATP level was further decreased, cells died neither via apoptosis nor via glutamate-dependent necrosis, in a manner similar to something like to energy catastrophe. Our results shows that cellular ATP content increases in cerebellar granule cell apoptosis, that the role of oxidative phosphorylation is facultative, i.e. ATP can also derive from anaerobic glycolysis, and that the type of cell death depends on the ATP availability.
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Affiliation(s)
- Anna Atlante
- Istituto di Biomembrane e Bioenergetica, CNR, Via G. Amendola, 165/A-70126 Bari, Italy.
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Ozeki T, Mitsui Y, Sugiya H, Furuyama S. Ribose 1,5-bisphosphate regulates rat kidney cortex phosphofructokinase. Comp Biochem Physiol B Biochem Mol Biol 1999; 124:327-32. [PMID: 10631808 DOI: 10.1016/s0305-0491(99)00127-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Phosphofructokinase (EC 2.7.1.11) is a major enzyme of the glycolytic pathway, catalyzing the conversion of fructose 6-phosphate to fructose 1,6-bisphosphate. In this study, we demonstrated the effect of ribose 1,5-bisphosphate on phosphofructokinase purified from rat kidney cortex. Ribose 1,5-bisphosphate relieved the phosphofructokinase from ATP inhibition and increased the affinity for fructose 6-phosphate at nanomolar concentrations. These activating effects of ribose 1,5-bisphosphate were enhanced in the presence of AMP. Ribose 1,5-bisphosphate reduced the inhibition of the phosphofructokinase induced by citrate. These results suggest that ribose 1,5-bisphosphate is an activator of rat kidney cortex phosphofructokinase and synergistically regulates the enzyme activity with AMP.
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Affiliation(s)
- T Ozeki
- Department of Physiology, Nihon University School of Dentistry, Chiba, Japan
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