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Grapentine S, Singh RK, Basu P, Sivanesan S, Mattos G, Oresajo O, Cheema J, Demeke W, Dolinsky VW, Bakovic M. Pcyt2 deficiency causes age-dependant development of nonalcoholic steatohepatitis and insulin resistance that could be attenuated with phosphoethanolamine. Sci Rep 2022; 12:1048. [PMID: 35058529 PMCID: PMC8776951 DOI: 10.1038/s41598-022-05140-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 01/06/2022] [Indexed: 12/19/2022] Open
Abstract
The mechanisms of NASH development in the context of age and genetics are not fully elucidated. This study investigates the age-dependent liver defects during NASH development in mice with heterozygous deletion of Pcyt2 (Pcyt2+/−), the rate limiting enzyme in phosphatidylethanolamine (PE) synthesis. Further, the therapeutic potential of Pcyt2 substrate, phosphoethanolamine (PEtn), is examined. Pcyt2+/− were investigated at 2 and 6–8 months (mo) of age and in addition, 6-mo old Pcyt2+/− with developed NASH were supplemented with PEtn for 8 weeks and glucose and fatty acid metabolism, insulin signaling, and inflammation were examined. Heterozygous ablation of Pcyt2 causes changes in liver metabolic regulators from young age, prior to the development of liver disease which does not occur until adulthood. Only older Pcyt2+/− experiences perturbed glucose and fatty acid metabolism. Older Pcyt2+/− liver develops NASH characterized by increased glucose production, accumulation of TAG and glycogen, and increased inflammation. Supplementation with PEtn reverses Pcyt2+/− steatosis, inflammation, and other aspects of NASH, showing that was directly caused by Pcyt2 deficiency. Pcyt2 deficiency is a novel mechanism of metabolic dysregulation due to reduced membrane ethanolamine phospholipid synthesis, and the metabolite PEtn offers therapeutic potential for NASH reversion.
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Taylor A, Grapentine S, Ichhpuniani J, Bakovic M. Choline transporter-like proteins 1 and 2 are newly identified plasma membrane and mitochondrial ethanolamine transporters. J Biol Chem 2021; 296:100604. [PMID: 33789160 PMCID: PMC8081925 DOI: 10.1016/j.jbc.2021.100604] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 03/24/2021] [Accepted: 03/26/2021] [Indexed: 12/31/2022] Open
Abstract
The membrane phospholipids phosphatidylcholine and phosphatidylethanolamine (PE) are synthesized de novo by the CDP-choline and CDP-ethanolamine (Kennedy) pathway, in which the extracellular substrates choline and ethanolamine are transported into the cell, phosphorylated, and coupled with diacylglycerol to form the final phospholipid product. Although multiple transport systems have been established for choline, ethanolamine transport is poorly characterized and there is no single protein assigned a transport function for ethanolamine. The solute carriers 44A (SLC44A) known as choline transporter-like proteins-1 and -2 (CTL1 and CTL2) are choline transporter at the plasma membrane and mitochondria. We report a novel function of CTL1 and CTL2 in ethanolamine transport. Using the lack or the gain of gene function in combination with specific antibodies and transport inhibitors we established two distinct ethanolamine transport systems of a high affinity, mediated by CTL1, and of a low affinity, mediated by CTL2. Both transporters are Na+-independent ethanolamine/H+ antiporters. Primary human fibroblasts with separate frameshift mutations in the CTL1 gene (M1= SLC44A1ΔAsp517 and M2= SLC44A1ΔSer126) are devoid of CTL1 ethanolamine transport but maintain unaffected CTL2 transport. The lack of CTL1 in M2 cells reduced the ethanolamine transport, the flux through the CDP-ethanolamine Kennedy pathway, and PE synthesis. In contrast, overexpression of CTL1 in M2 cells improved ethanolamine transport and PE synthesis. These data firmly establish that CTL1 and CTL2 are the first identified ethanolamine transporters in whole cells and mitochondria, with intrinsic roles in de novo PE synthesis by the Kennedy pathway and intracellular redistribution of ethanolamine.
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Affiliation(s)
- Adrian Taylor
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Canada
| | - Sophie Grapentine
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Canada
| | - Jasmine Ichhpuniani
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Canada
| | - Marica Bakovic
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Canada.
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Sperber S, Wahl M, Berger F, Kamp H, Lemke O, Starck V, Walk T, Spitzer M, Ravenzwaay B. Metabolomics as read-across tool: An example with 3-aminopropanol and 2-aminoethanol. Regul Toxicol Pharmacol 2019; 108:104442. [DOI: 10.1016/j.yrtph.2019.104442] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 08/12/2019] [Accepted: 08/12/2019] [Indexed: 01/06/2023]
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Sibomana I, Grobe N, DelRaso NJ, Reo NV. Influence of Myo-inositol Plus Ethanolamine on Plasmalogens and Cell Viability during Oxidative Stress. Chem Res Toxicol 2019; 32:265-284. [PMID: 30604967 DOI: 10.1021/acs.chemrestox.8b00280] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Previously, we demonstrated that treatment of rats with myo-inositol plus ethanolamine (ME) elevated brain ethanolamine plasmalogens (PE-Pls) and protected against phosphine-induced oxidative stress. Here we tested the hypothesis that ME treatment elevates PE-Pls in a neuro-2A (N2A) cell culture system and protects against hydrogen peroxide (H2O2)-induced oxidative stress, and we assessed the effects of treatments using myo-inositol with or without (+/-) ethanolamine on ethanolamine phospholipids (PLs) and cell viability following H2O2 exposure. Cells were treated with equimolar amounts (500 μM) of myo-inositol, ethanolamine (Etn), or their combination (ME) for 24 h, followed by an additional 24 h exposure to 650 μM H2O2. NMR analyses evaluated the treatment effects on Etn PLs, while LC-MS/MS analyses assessed the molecular species of Etn PLs preferentially affected by ME and H2O2 treatments, especially PE-Pls and their degradation byproducts-lysophosphatidylethanolamine (LPE) and glycerophosphoethanolamine (GPE). Only ME influenced the cellular levels of PLs. ME yielded a 3-fold increase in PE-Pls and phosphatidylethanolamine (PE) ( p < 0.001) and a preferential 60% increase in PE-Pls containing saturated and monounsaturated fatty acids (SFA+MUFA), while polyunsaturated fatty acid (PUFA) species increased by only 10%. Exposing cells to 650 μM H2O2 caused a significant cell death (56% viability), a 27% decrease in PE-Pls, a 201% increase in PUFA-rich LPE, and a ca. 3-fold increase in GPE. H2O2 had no impact on PE, suggesting that LPE and GPE were primarily the byproducts of PE-Pls (not PE) degradation. Surprisingly, ME pretreatment ameliorated H2O2 effects and significantly increased cell survival to 80% ( p < 0.05). Cellular PE-Pls levels prior to H2O2 treatment were highly correlated ( R2 = 0.95) with cell survival, suggesting a relationship between PE-Pls and cell protection. Data suggest that a preferential increase in PE-Pls containing SFA+MUFA species may protect cells from oxidative stress. Such studies aid in our understanding of the neuroprotective mechanisms that may be associated with plasmalogens and the relevance of these phospholipids to neurodegenerative diseases/disorders.
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Affiliation(s)
- Isaie Sibomana
- Department of Biochemistry and Molecular Biology, Magnetic Resonance Laboratory, Boonshoft School of Medicine, 162 Diggs Laboratory , Wright State University , Dayton , Ohio 45435 , United States.,Molecular Mechanisms Branch, Human-Centered ISR Division, Airman Systems Directorate, 711th Human Performance Wing , Air Force Research Laboratory , Wright-Patterson Air Force Base , Ohio 45433 , United States
| | - Nadja Grobe
- Molecular Mechanisms Branch, Human-Centered ISR Division, Airman Systems Directorate, 711th Human Performance Wing , Air Force Research Laboratory , Wright-Patterson Air Force Base , Ohio 45433 , United States
| | - Nicholas J DelRaso
- Molecular Mechanisms Branch, Human-Centered ISR Division, Airman Systems Directorate, 711th Human Performance Wing , Air Force Research Laboratory , Wright-Patterson Air Force Base , Ohio 45433 , United States
| | - Nicholas V Reo
- Department of Biochemistry and Molecular Biology, Magnetic Resonance Laboratory, Boonshoft School of Medicine, 162 Diggs Laboratory , Wright State University , Dayton , Ohio 45435 , United States
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Shah T, Krishnamachary B, Wildes F, Wijnen JP, Glunde K, Bhujwalla ZM. Molecular causes of elevated phosphoethanolamine in breast and pancreatic cancer cells. NMR IN BIOMEDICINE 2018; 31:e3936. [PMID: 29928787 PMCID: PMC6118328 DOI: 10.1002/nbm.3936] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 04/05/2018] [Accepted: 04/06/2018] [Indexed: 05/03/2023]
Abstract
Elevated phosphoethanolamine (PE) is frequently observed in MRS studies of human cancers and xenografts. The role of PE in cell survival and the molecular causes underlying this increase are, however, relatively underexplored. In this study, we investigated the roles of ethanolamine kinases (Etnk-1 and 2) and choline kinases (Chk-α and β) in contributing to increased PE in human breast and pancreatic cancer cells. We investigated the effect of silencing Etnk-1 and Etnk-2 on cell viability as a potential therapeutic strategy. Both breast and pancreatic cancer cells showed higher PE compared with their nonmalignant counterparts. We identified Etnk-1 as a major cause of the elevated PE levels in these cancer cells, with little or no contribution from Chk-α, Chk-β, or Etnk-2. The increase of PE observed in pancreatic cancer cells in culture was replicated in the corresponding tumor xenografts. Downregulation of Etnk-1 with siRNA resulted in cell cytotoxicity that correlated with PE levels in breast and pancreatic cancer cells. Etnk-1 may provide a potential therapeutic target in breast and pancreatic cancers.
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Affiliation(s)
- Tariq Shah
- Division of Cancer Imaging Research, The Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Balaji Krishnamachary
- Division of Cancer Imaging Research, The Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Flonne Wildes
- Division of Cancer Imaging Research, The Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Jannie P. Wijnen
- Division of Cancer Imaging Research, The Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, School of Medicine, Baltimore, MD, USA
- Centre of Image Sciences/High field MR Research group, Radiology, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Kristine Glunde
- Division of Cancer Imaging Research, The Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, School of Medicine, Baltimore, MD, USA
- Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Zaver M. Bhujwalla
- Division of Cancer Imaging Research, The Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, School of Medicine, Baltimore, MD, USA
- Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University, School of Medicine, Baltimore, MD, USA
- Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University, School of Medicine, Baltimore, MD, USA
- Correspondence: Zaver M. Bhujwalla, PhD, Division of Cancer Imaging Research, Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, 720 Rutland Avenue, Rm 208C Traylor Building, Baltimore, MD 21205, USA, Phone: +1 (410) 955 9698 | Fax: +1 (410) 614 1948,
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Implantation loss induced by ethanolamine in the rat is ameliorated by a choline-supplemented diet. Reprod Toxicol 2018; 78:102-110. [DOI: 10.1016/j.reprotox.2018.04.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 04/03/2018] [Accepted: 04/06/2018] [Indexed: 12/14/2022]
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Phorbol ester stimulates ethanolamine release from the metastatic basal prostate cancer cell line PC3 but not from prostate epithelial cell lines LNCaP and P4E6. Br J Cancer 2014; 111:1646-56. [PMID: 25137020 PMCID: PMC4200097 DOI: 10.1038/bjc.2014.457] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 07/09/2014] [Accepted: 07/21/2014] [Indexed: 12/11/2022] Open
Abstract
Background: Malignancy alters cellular complex lipid metabolism and membrane lipid composition and turnover. Here, we investigated whether tumorigenesis in cancer-derived prostate epithelial cell lines influences protein kinase C-linked turnover of ethanolamine phosphoglycerides (EtnPGs) and alters the pattern of ethanolamine (Etn) metabolites released to the medium. Methods: Prostate epithelial cell lines P4E6, LNCaP and PC3 were models of prostate cancer (PCa). PNT2C2 and PNT1A were models of benign prostate epithelia. Cellular EtnPGs were labelled with [1-3H]-Etn hydrochloride. PKC was activated with phorbol ester (TPA) and inhibited with Ro31-8220 and GF109203X. D609 was used to inhibit PLD (phospholipase D). [3H]-labelled Etn metabolites were resolved by ion-exchange chromatography. Sodium oleate and mastoparan were tested as activators of PLD2. Phospholipase D activity was measured by a transphosphatidylation reaction. Cells were treated with ionomycin to raise intracellular Ca2+ levels. Results: Unstimulated cell lines release mainly Etn and glycerylphosphorylEtn (GPEtn) to the medium. Phorbol ester treatment over 3h increased Etn metabolite release from the metastatic PC3 cell line and the benign cell lines PNT2C2 and PNT1A but not from the tumour-derived cell lines P4E6 and LNCaP; this effect was blocked by Ro31-8220 and GF109203X as well as by D609, which inhibited PLD in a transphosphatidylation reaction. Only metastatic PC3 cells specifically upregulated Etn release in response to TPA treatment. Oleate and mastoparan increased GPEtn release from all cell lines at the expense of Etn. Ionomycin stimulated GPEtn release from benign PNT2C2 cells but not from cancer-derived cell lines P4E6 or PC3. Ethanolamine did not stimulate the proliferation of LNCaP or PC3 cell lines but decreased the uptake of choline (Cho). Conclusions: Only the metastatic basal PC3 cell line specifically increased the release of Etn on TPA treatment most probably by PKC activation of PLD1 and increased turnover of EtnPGs. The phosphatidic acid formed will maintain a cancer phenotype through the regulation of mTOR. Ethanolamine released from cells may reduce Cho uptake, regulating the membrane PtdEtn:PtdCho ratio and influencing the action of PtdEtn-binding proteins such as RKIP and the anti-apoptotic hPEBP4. The work highlights a difference between LNCaP cells used as a model of androgen-dependent early stage PCa and androgen-independent PC3 cells used to model later refractory stage disease.
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Demetriades AK, Almeida AC, Bhangoo RS, Barrington SF. Applications of positron emission tomography in neuro-oncology: a clinical approach. Surgeon 2014; 12:148-57. [PMID: 24629841 DOI: 10.1016/j.surge.2013.12.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 12/03/2013] [Indexed: 11/20/2022]
Abstract
The field of neuro-oncology is concerned with some of the most challenging and difficult to treat conditions in medicine. Despite modern therapies patients diagnosed with primary brain tumours often have a poor prognosis. Imaging can play an important role in evaluating the disease status of such patients. In addition to the structural information derived from MRI and CT scans, positron emission tomography (PET) provides important quantitative metabolic assessment of brain tumours. This review describes the use of PET with radiolabelled glucose and amino acid analogues to aid in the diagnosis of tumours, differentiate between recurrent tumour and radiation necrosis and guide biopsy or treatment. [(18)F]Fluorodeoxyglucose (FDG) is the tracer that has been used most widely because it has a 2 h half life and can be transported to imaging centres remote from the cyclotron and radiochemistry facilities which synthesise the tracers. The high uptake of FDG in normal grey matter however limits its use in some low grade tumours which may not be visualised. [(11)C] methionine (MET) is an amino acid tracer with low accumulation in normal brain which can detect low grade gliomas, but its short 20 min half life has limited its use to imaging sites with their own cyclotron. The emergence of new fluorinated amino acid tracers like [(18)F]Fluoroethyl-l-tyrosine (FET) will likely increase the availability and utility of PET for patients with primary brain tumours. PET can, further, characterise brain tumours by investigating other metabolic processes such as DNA synthesis or thymidine kinase activity, phospholipid membrane biosynthesis, hypoxia, receptor binding and oxygen metabolism and blood flow, which will be important in the future assessment of targeted therapy.
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Affiliation(s)
- Andreas K Demetriades
- Department of Neurosurgery, King's College Hospital, Denmark Hill, London SE5 9RS, UK.
| | - Andre Cardoso Almeida
- Department of Neurosurgery, King's College Hospital, Denmark Hill, London SE5 9RS, UK
| | - Ranj S Bhangoo
- Department of Neurosurgery, King's College Hospital, Denmark Hill, London SE5 9RS, UK
| | - Sally F Barrington
- Department of Nuclear Medicine, PET Imaging Centre, St. Thomas' Hospital, Lambeth Palace Road, London SE1 7EH, UK
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Farine L, Bütikofer P. The ins and outs of phosphatidylethanolamine synthesis in Trypanosoma brucei. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1831:533-42. [PMID: 23010476 DOI: 10.1016/j.bbalip.2012.09.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 09/07/2012] [Accepted: 09/16/2012] [Indexed: 12/23/2022]
Abstract
Phospholipids are not only major building blocks of biological membranes but fulfill a wide range of critical functions that are often widely unrecognized. In this review, we focus on phosphatidylethanolamine, a major glycerophospholipid class in eukaryotes and bacteria, which is involved in many unexpected biological processes. We describe (i) the ins, i.e. the substrate sources and biochemical reactions involved in phosphatidylethanolamine synthesis, and (ii) the outs, i.e. the different roles of phosphatidylethanolamine and its involvement in various cellular events. We discuss how the protozoan parasite, Trypanosoma brucei, has contributed and may contribute in the future as eukaryotic model organism to our understanding of phosphatidylethanolamine homeostasis. This article is part of a Special Issue entitled Phospholipids and Phospholipid Metabolism.
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Affiliation(s)
- Luce Farine
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012 Bern, Switzerland.
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Improved quality control of [18F]fluoromethylcholine. Nucl Med Biol 2011; 38:1143-8. [DOI: 10.1016/j.nucmedbio.2011.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 04/28/2011] [Accepted: 05/03/2011] [Indexed: 11/20/2022]
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Wu HB, Wang QS, Wang MF, Zhen X, Zhou WL, Li HS. Preliminary study of 11C-choline PET/CT for T staging of locally advanced nasopharyngeal carcinoma: comparison with 18F-FDG PET/CT. J Nucl Med 2011; 52:341-6. [PMID: 21321282 DOI: 10.2967/jnumed.110.081190] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Evaluation of nasopharyngeal carcinoma (NPC) using (18)F-FDG PET/CT is limited by the intense physiologic uptake of (18)F-FDG in the brain. We attempted to improve detection of intracranial tumor invasion (including better delineation of invasion near the skull base) in locally advanced NPC using(11)C-choline PET/CT. METHODS Fifteen patients with newly diagnosed or recurrent locally advanced NPC were enrolled in the study. (18)F-FDG and (11)C-choline PET/CT was performed on all patients. PET/CT images obtained using the 2 tracers were compared using both maximum standardized uptake value (SUVmax) and tumor-to-brain (T/B) ratios. All patients were followed up for more than 1 y. RESULTS The sensitivity of (18)F-FDG PET/CT in detecting locally advanced NPC was 86.6%, compared with a 100% sensitivity for (11)C-choline PET/CT (t = 2.143, P = 0.483). The SUVmax of lesions detected was higher using (18)F-FDG than using (11)C-choline (12.81 ± 5.00 vs. 6.84 ± 2.76, t = 6.416, P < 0.001), but the T/B ratio was much higher for (11)C-choline than for (18)F-FDG (18.62 ± 7.95 vs. 1.38 ± 0.59, t = 8.801, P < 0.001). Compared with (18)F-FDG PET/CT, (11)C-choline PET/CT improved the delineation of intracranial invasion in 6 of 12 patients (χ(2) = 8.00, P = 0.014), skull base invasion in 4 of 14 patients, and orbital invasion in 3 of 3 patients. CONCLUSION (11)C-choline can improve the quality of PET/CT in the T staging of NPC.
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Affiliation(s)
- Hu-bing Wu
- Nanfang Hospital, Southern Medical University, Guangzhou, China
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12
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Lam WWC, Ng DCE, Wong WY, Ong SC, Yu SWK, See SJ. Promising role of [18F] fluorocholine PET/CT vs [18F] fluorodeoxyglucose PET/CT in primary brain tumors—Early experience. Clin Neurol Neurosurg 2011; 113:156-61. [DOI: 10.1016/j.clineuro.2010.09.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Revised: 06/30/2010] [Accepted: 09/22/2010] [Indexed: 11/24/2022]
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13
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Simplified fast and high yielding automated synthesis of [18F]fluoroethylcholine for prostate cancer imaging. Bioorg Med Chem 2008; 16:9121-6. [DOI: 10.1016/j.bmc.2008.09.031] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Revised: 09/03/2008] [Accepted: 09/10/2008] [Indexed: 11/18/2022]
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Piel M, Bauman A, Baum R, Höhnemann S, Klette I, Wortmann R, Rösch F. Improved automated synthesis of [18F]fluoroethylcholine as a radiotracer for cancer imaging. Bioorg Med Chem 2007; 15:3171-5. [DOI: 10.1016/j.bmc.2007.02.038] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2006] [Revised: 02/15/2007] [Accepted: 02/20/2007] [Indexed: 11/30/2022]
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15
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Hara T, Bansal A, DeGrado TR. Choline Transporter as a Novel Target for Molecular Imaging of Cancer. Mol Imaging 2006. [DOI: 10.2310/7290.2006.00032] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Toshihiko Hara
- From the Department of Radiology, Indiana University School of Medicine, Indianapolis, IN
| | - Aditya Bansal
- From the Department of Radiology, Indiana University School of Medicine, Indianapolis, IN
| | - Timothy R. DeGrado
- From the Department of Radiology, Indiana University School of Medicine, Indianapolis, IN
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Kansara V, Luo S, Balasubrahmanyam B, Pal D, Mitra AK. Biotin uptake and cellular translocation in human derived retinoblastoma cell line (Y-79): A role of hSMVT system. Int J Pharm 2006; 312:43-52. [PMID: 16459033 DOI: 10.1016/j.ijpharm.2005.12.045] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2005] [Revised: 11/19/2005] [Accepted: 12/20/2005] [Indexed: 11/21/2022]
Abstract
The objective of this research was to investigate the presence of a specialized carrier-mediated system for biotin and delineate uptake mechanism and intracellular trafficking of biotin in the human derived retinoblastoma cell line (Y-79). Human derived retinoblastoma cell line, Y-79, was used for uptake studies. Uptake of [3H]Biotin was determined at various concentrations, pH, temperatures, in the absence of sodium and in the presence of other vitamins and metabolic inhibitors to delineate the mechanism of uptake. Uptake was determined in the presence of various intracellular regulatory pathways (protein kinase A & C, protein tyrosine kinase and calcium-calmodulin) modulators. Reverse transcription polymerase chain reaction (RT-PCR) was performed to confirm the molecular identity of human sodium-dependent multivitamin transporter (hSMVT). Uptake of [3H]Biotin in Y-79 cells were found to be saturable at micromolar concentration range, with apparent Km of 8.53 microM and Vmax of 14.12 pmol/min/mg protein, but linear at nanomolar concentration range. Uptake was sodium, pH, temperature and energy-dependent, but chloride independent; inhibited by the structural analogue desthiobiotin, pantothenic acid and lipoic acid at milimolar concentrations and not at nanomolar concentrations. Uptake of [3H]Biotin was trans-stimulated by the intracellular biotin. Ca2+/calmodulin pathways appeared to play important roles in the regulation of riboflavin uptake in Y-79 cells via significant reduction in Vmax (66%) and Km (28%) of the uptake process. A human sodium-dependant multivitamin transporter, hSMVT, was identified by RT-PCR in Y-79. These studies demonstrated for the first time the existence of a human sodium dependant multivitamin transporter (hSMVT), a specialized carrier-mediated system for biotin uptake, in human derived retinoblastoma cells.
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Affiliation(s)
- Viral Kansara
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri Kansas city, 5005 Rockhill Road, Kansas city, MO 64110-2499, USA
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Kansara V, Pal D, Jain R, Mitra AK. Identification and functional characterization of riboflavin transporter in human-derived retinoblastoma cell line (Y-79): mechanisms of cellular uptake and translocation. J Ocul Pharmacol Ther 2005; 21:275-87. [PMID: 16117691 DOI: 10.1089/jop.2005.21.275] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Drug delivery to the retina is a challenging task owing to its complex physiology and presence of the blood-retinal barrier (BRB), which regulates the permeation of substances from blood into the retina. Transporter-targeted drug delivery has become a clinically significant drug-delivery approach for enhancing the bioavailability of various drugs. Different nutrient transporters have been reported to be expressed on the retina. Riboflavin (vitamin B2), an essential nutritional vitamin for the development and maintenance of the surface structures and functions of epithelial cells of the ocular tissues, must be acquired from retinal or choroidal blood supply. The uptake mechanism, cellular translocation, and major regulatory pathways of riboflavin uptake into retina are poorly understood. Therefore, the aim of this study was to investigate the presence of a riboflavin transporter and delineate uptake and intracellular trafficking of riboflavin in the human-derived retinoblastoma cell line (Y-79), a model for neural retina. Uptake characteristics of [3H]riboflavin in Y-79 cells were found to be (1) linear with time over 10 min of incubation; (2) temperature- and energy-dependent; (3) sodium, chloride-, and pH-independent; (4) concentration dependence with an apparent K(m) of 19.21 +/- 0.37 nM and V(max) of 6.98 +/- 0.30 pmol/min/mg protein; (5) inhibited by the structural analogs (lumiflavin and lumichrome) but not by the structurally unrelated vitamins; and (6) uptake of [3H]riboflavin was trans-stimulated by the intracellular riboflavin. Neither protein kinase C- nor protein tyrosine kinase-mediated pathways were involved in regulating riboflavin uptake. However, protein kinase A pathway activators (IBMX and forskolin) and inhibitors (H-89) and Ca2+/calmodulin pathways appeared to play important roles in the regulation of riboflavin uptake in Y-79 cells through significant reduction in V(max) (39%) and significant increase in K(m) (112%) of the uptake process. These studies demonstrated, for the first time, the existence of a specialized carrier-mediated system for riboflavin uptake in human-derived retinoblastoma cells. The system appears to be regulated by protein kinase A and Ca2+/calmodulin pathways. Being a high-affinity low-capacity transport system, the presence of this transporter on the retina may be suitable for the design of transporter-targeted prodrugs to achieve enhanced permeability for highly potent, but poorly bioavailable, compounds where a small increase in the bioavailability could result in a significant increase in therapeutic response.
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Affiliation(s)
- Viral Kansara
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri Kansas City, Kansas City, MO 64112-2499, USA
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18
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Hara T, Kosaka N, Suzuki T, Kudo K, Niino H. Uptake rates of 18F-fluorodeoxyglucose and 11C-choline in lung cancer and pulmonary tuberculosis: a positron emission tomography study. Chest 2003; 124:893-901. [PMID: 12970014 DOI: 10.1378/chest.124.3.893] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
STUDY OBJECTIVE The purpose of this study was to examine the uptake rates of (18)F-fluorodeoxyglucose (FDG) and (11)C-choline in patients with lung cancer, pulmonary tuberculosis, and atypical mycobacterial infection of the lung by positron emission tomography (PET) scanning with relation to their tumor size. DESIGN Ninety-seven patients with untreated lung cancer, 14 patients with untreated pulmonary tuberculosis, and 5 patients with untreated atypical mycobacterial infection were examined. The diagnosis of lung cancer was confirmed pathologically after biopsy and surgery. The diagnosis of tuberculosis and atypical mycobacterial infection was confirmed by bacterial culture. The uptake rates of FDG and (11)C-choline were presented quantitatively as the standardized uptake value (SUV). SETTING International Medical Center of Japan. RESULTS In lung cancer patients, the SUV of FDG increased with increasing tumor size, whereas the SUV of (11)C-choline was almost constant at around 3.5 for every tumor size. In tuberculosis patients, the SUV of FDG increased with increasing tumor size, whereas the SUV of (11)C-choline was almost constant at around 2 for every tumor size. In atypical mycobacterial infection patients, the SUV of FDG and the SUV of (11)C-choline were equally low at around < or = 2. CONCLUSION The differences in the SUVs of FDG and (11)C-choline in patients with lung cancer, tuberculosis, and atypical mycobacterial infection for the same tumor size (tumor size, > 1.5 cm) were distinct. In lung cancer patients, the SUVs of both FDG and (11)C-choline were high. In tuberculosis patients, the SUV of FDG was high, but the SUV of (11)C-choline was low. In atypical mycobacterial infection patients, the SUVs of both FDG and (11)C-choline were low. It may be possible to apply this principle to make a presumptive diagnosis of a solitary pulmonary nodule if it is too small to make a definitive diagnosis pathologically and bacteriologically.
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Affiliation(s)
- Toshihiko Hara
- Department of Radiology, International Medical Center of Japan, Tokyo, Japan.
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19
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Abstract
Choline has many physiological functions throughout the body that are dependent on its available local supply. However, since choline is a charged hydrophilic cation, transport mechanisms are required for it to cross biological membranes. Choline transport is required for cellular membrane construction and is the rate-limiting step for acetylcholine production. Transport mechanisms include: (1) sodium-dependent high-affinity uptake mechanism in synaptosomes, (2) sodium-independent low-affinity mechanism on cellular membranes, and (3) unique choline uptake mechanisms (e.g., blood-brain barrier choline transport). A comprehensive overview of choline transport studies is provided. This review article examines landmark and current choline transport studies, molecular mapping, and molecular identification of these carriers. Information regarding the choline-binding site is presented by reviewing choline structural analog (hemicholinium-3 and 15, and other nitrogen/methyl-hydroxyl compounds) inhibition studies. Choline transport in Alzheimer's disease, brain ischemic events, and aging is also discussed. Emphasis throughout the article is placed on targeting the choline transporter in disease and use of this carrier as a drug delivery vector.
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Affiliation(s)
- P R Lockman
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, Texas 79106-1712, USA
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20
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Huang MC, Muddana S, Horowitz EN, McCormick CC, Infante JP, Brenna JT. High-precision isotope ratio mass spectrometry and stable isotope precursors for tracer studies in cell culture. Anal Biochem 2000; 287:80-6. [PMID: 11078586 DOI: 10.1006/abio.2000.4843] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The use of stable isotope-labeled tracers is demonstrated in an in vitro system with analysis by high-precision isotope ratio mass spectrometry (IRMS), using n-3 long-chain polyunsaturated fatty acid (LCP) biosynthesis from [U-(13)C]18:3n-3 (18:3n-3*) in Y79 human retinoblastoma cells as a model system. The cells were cultured as a suspension in RPMI 1640 medium supplemented with 15% fetal calf serum at 37 degrees C with 5% CO(2) in air. They were harvested by sedimentation and cell lipids were extracted to determine the presence of 18:3n-3* metabolites using gas chromatography-combustion (GCC)-IRMS. As the dose of 18:3n-3* was systematically increased from treatment to treatment, the atom percent excess and the amounts of biosynthesized LCP* increased, while the percentage dose in each n-3 LCP* remained constant. Cultures incubated with 0.5 micromol (10 microM) of albumin-bound 18:3n-3, composed of 18:3n-3* diluted 1/60 or 1/100 with natural abundance 18:3n-3, yielded products with enrichments about 1.5 at.% excess (delta(13)C(PDB) < 1500 per thousand), which is optimal for high-precision measurements. Kinetics in Y79 cells incubated with 18:3n-3* showed that n-3 LCP* incorporation increased over time; 18:3n-3*, 20:5n-3*, 22:5n-3*, and 22:6n-3* were detected at all time points with the 1/60 dilution. These data document experimental parameters for optimal stable isotope use and IRMS detection for in vitro tracer methodology.
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Affiliation(s)
- M C Huang
- Division of Nutritional Sciences, Cornell University, Ithaca, New York 14850, USA
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21
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Ikemoto A, Kobayashi T, Emoto K, Umeda M, Watanabe S, Okuyama H. Effects of docosahexaenoic and arachidonic acids on the synthesis and distribution of aminophospholipids during neuronal differentiation of PC12 cells. Arch Biochem Biophys 1999; 364:67-74. [PMID: 10087166 DOI: 10.1006/abbi.1999.1110] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have shown previously that docosahexaenoic acid (DHA) promotes and arachidonic acid (AA) suppresses neurite outgrowth of PC12 cells induced by nerve growth factor (NGF) and that incorporation of [3H]ethanolamine into phosphatidylethanolamine (PE) is suppressed in PC12 cells by AA while DHA has no effect. In the present study, the effects of these fatty acids on PE synthesis via decarboxylation of phosphatidylserine (PS), another pathway of PE synthesis, and distribution of aminophospholipids were examined. Incorporation of [3H]serine into PS and PE was elevated in the course of NGF-induced differentiation and was further stimulated significantly by DHA, but not by AA. [3H]Ethanolamine uptake by PC12 cells was significantly suppressed by AA but not by DHA while these fatty acids did not affect [3H]serine uptake, indicating that the suppression by AA of [3H]ethanolamine incorporation into phosphatidylethanolamine is attributable, at least in part, to a reduction in [3H]ethanolamine uptake. The distribution of PE in the outer leaflet of plasma membrane decreased during differentiation, which is known to be accompanied by an increase in the surface area of plasma membrane. Supplementation of PC12 cells with DHA or AA did not affect the distribution of aminophospholipids. Thus, DHA and AA affected aminophospholipid synthesis and neurite outgrowth differently, but not the transport and distribution of aminophospholipids, while the PE concentration in the outer leaflet of the plasma membrane decreased in association with morphological changes in PC12 cells induced by NGF.
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Affiliation(s)
- A Ikemoto
- Faculty of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabedori, Nagoya, Mizuhoku, 467-8603, Japan.
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22
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The CDP-ethanolamine pathway in mammalian cells. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s1874-5245(97)80013-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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23
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Rifkin MR, Strobos CA, Fairlamb AH. Specificity of ethanolamine transport and its further metabolism in Trypanosoma brucei. J Biol Chem 1995; 270:16160-6. [PMID: 7608181 DOI: 10.1074/jbc.270.27.16160] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Ethanolamine is found in trypanosomes as an integral component of the variant surface glycoprotein (VSG) and the membrane phospholipid phosphatidylethanolamine (PE). Steps in the utilization of ethanolamine could represent novel targets for the development of chemotherapeutic drugs and were therefore investigated in detail. Transport of [3H]ethanolamine was studied using structural analogs of ethanolamine. Compounds with substitutions in the amino group or of one of the methylene hydrogens of ethanolamine were the most effective inhibitors. Those analogs studied in detail with respect to their kinetic properties were all found to be competitive inhibitors of ethanolamine transport. Following uptake, ethanolamine is rapidly phosphorylated by an ethanolamine-specific kinase to form phosphoethanolamine. Other acid-soluble intermediates identified by thin layer chromatography were CDP-ethanolamine, dCDP-ethanolamine, and glycerophosphorylethanolamine. The relative amounts of these metabolites varied between slender (dividing) and stumpy (non-dividing) trypanosomes and may reflect special biosynthetic needs of the different morphological forms. Pulse-chase experiments indicated that the acid-soluble metabolites served as precursors for chloroform/methanol-soluble lipids. Radioactive lipids included PE, mono-methyl and dimethyl PE, and lysoPE. Further methylation of dimethylPE to phosphatidylcholine was not observed under the experimental conditions described. These results are consistent with the conclusion that trypanosomes are able to synthesize phospholipids via the Kennedy pathway.
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Affiliation(s)
- M R Rifkin
- Laboratory of Medical Biochemistry, Rockefeller University, New York, New York 10021, USA
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24
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Chu AJ, Lee JM. Lidocaine inhibits choline uptake and phosphatidylcholine biosynthesis in human leukemic monocyte-like U937 cells. Cell Biochem Funct 1994; 12:89-98. [PMID: 8044894 DOI: 10.1002/cbf.290120203] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The effect of lidocaine on [3H]choline uptake and the incorporation of label into phosphatidylcholine (PC) in human monocyte-like U937 cells was investigated. Lidocaine inhibited the rate of choline uptake in a dose-dependent manner; at 3.2 mM it resulted in a drastic reduction, by as much as 65 per cent (n = 10; p < 0.0005) or 55 per cent (n = 10; p < 0.0006) in a 3- or 6-h incubation, respectively. Lidocaine also decreased the rate of choline incorporation into PC in a dose-dependent manner. At the highest dose, nearly 70 per cent or 45 per cent reduction was seen in a 3- or 6-h incubation, respectively. Analysis of choline-containing metabolites showed that the major label association with phosphocholine and PC was reduced to a similar extent which was also parallel to the inhibition of choline uptake. At 3.2 mM lidocaine, the reduction of choline uptake was shown to follow a competitive inhibition. In the case of [3H] choline incorporation into PC, the inhibitory pattern was shown to be of a mixed type. The pulse-chase study dissecting the effect on choline metabolism from that on total choline uptake indicated that lidocaine exerted an additionally inhibitory effect on intracellular choline metabolism into PC. In a separate protocol in which the labelled cells were first allowed to be chased until 3H-incorporation into PC reached a steady state, lidocaine no longer showed any effect. These results seem to exclude the possibility of enhanced PC breakdown and further suggest that the main inhibitory effect is on the CDP-choline pathway for PC biosynthesis. After a 3-h treatment, CTP: cholinephosphate cytidylyltransferase (CYT) in both the cytosolic and microsomal fractions was inhibited by approximately 20 per cent, while choline kinase (CK) and choline phosphotransferase (CPT) remain relatively unchanged. There was no evidence for translocation of CYT between cytosol and microsomes. Taken together, we have demonstrated a dual inhibitory function of lidocaine which inhibits PC biosynthesis in addition to its ability to block choline uptake profoundly in U937 cells.
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Affiliation(s)
- A J Chu
- Miami Heart Institute, Miami Beach, FL 33140-2999
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25
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Chu AJ. Stimulation of phosphatidylcholine biosynthesis by hemicholinium-3, a potent inhibitor of choline uptake in human leukemic monocyte-like U937 cells. Cell Biochem Funct 1994; 12:79-88. [PMID: 8044893 DOI: 10.1002/cbf.290120202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The effect of hemicholinium-3 (HC-3) on choline uptake and phosphatidylcholine (PC) biosynthesis was examined in human leukemic monocyte-like U937 cells. HC-3 inhibited [3H]choline uptake in a dose- and time-dependent manner. After a 3 h treatment, HC-3 (100 microM) decreased choline uptake by as much as 80 per cent (p < 0.0001; n = 4). Reduction of incorporation of label into PC was also detected in a dose-dependent manner; the extent of inhibition, however, was always 10-20 per cent less than that observed in the total uptake. At 3 h HC-3 decreased the incorporation into PC by 65 per cent (p < 0.0001; n = 5). Kinetic studies in vivo showed that HC-3 inhibited total uptake and incorporation into PC differently, suggesting that the labelling of PC is not simply dictated by [3H]choline uptake. In separate experiments, cells were pretreated with 100 microM HC-3 for 3 h. After washing, the inhibitory effect on total uptake was no longer observed, while a 20 per cent stimulation of the incorporation into PC was obtained in these pretreated cells. In pulse-chase studies, the cells were prelabelled with [3H]choline for 30 min and chased with HC-3 for up to 3 h; the results showed a significant stimulation of incorporation into PC in a longer chase with 100 microM HC-3. After a 3 h treatment, the cytosolic CTP:cholinephosphate cytidylyltransferase (CT) was activated by 56 per cent, while choline kinase (CK) was inhibited slightly. The stimulation of CT was not simply due to the intact HC-3 molecule, and there was no redistribution of CT between cytosol and microsomes. Taken together, the results suggest that HC-3 activates PC biosynthesis apart from the inhibitory effect on choline uptake.
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Affiliation(s)
- A J Chu
- Miami Heart Institute, Miami Beach, FL 33140
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26
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Chu AJ, Nguyen CT, Moore J. Differential effects of unsaturated fatty acids on phospholipid synthesis in human leukemia monocytic U937 cells. Cell Biochem Funct 1993; 11:201-9. [PMID: 8403234 DOI: 10.1002/cbf.290110308] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The biosynthesis of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) in monocyte-like leukemia U937 cells was monitored by adding [3H]choline, [14C]ethanolamine or [14C]glycerol to the culture media; incorporation into phospholipid (PL) increased with time. The effect of unsaturated fatty acids (UFA) on PC and PE synthesis was investigated by pretreating U937 cells for 72h with 10 microM 18:1 (n - 9), 18:2 (n - 6), 18:3 (n - 3), 20:4 (n - 6) and 20:5 (n - 3). The UFA caused no alteration in cell growth, as evidenced by light microscopy and the incorporation of [3H]thymidine and [3H]leucine. Total cellular uptake of radioactive precursors remained unaffected by all the treatments. Pretreatment with 20:5 resulted in approximately 25 per cent reduction in the incorporation of [3H]choline into PL, while no significant effect was detected with the other UFAs. 18:3, 20:4 and 20:5 depressed the incorporation of [14C]ethanolamine into PL by 34 per cent, 28 per cent and 49 per cent respectively. However, there was no redistribution of label with any of the treatments. 18:3, 20:4 and 20:5 also antagonized the stimulatory effect of endotoxin (LPS) on PC and PE synthesis. In addition, the incorporation from [14C]glycerol into PC and PE was reduced by 18:3, 20:4 and 20:5. Although the PL composition of the cells remained essentially unaffected, our study shows that chronic treatment of U937 cells with n - 3 PUFA (20:5) depressed PC and PE synthesis, and 18:3 and 20:4 also caused inhibition of PE synthesis.
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Affiliation(s)
- A J Chu
- Research Division, Miami Heart Institute, Miami Beach, FL 33140-2999
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Miller RR, Yates JW, Geer BW. Dietary ethanol reduces phosphatidylcholine levels and inhibits the uptake of dietary choline in Drosophila melanogaster larvae. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. COMPARATIVE PHYSIOLOGY 1993; 104:837-44. [PMID: 8097990 DOI: 10.1016/0300-9629(93)90163-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
1. Low to moderate concentrations of dietary ethanol (200 mM to 600 mM) significantly increased the level of phosphatidylethanolamine (PE), while phosphatidylcholine (PC) levels decreased in third instar larvae. This was seen in both ethanol tolerant and intolerant strains of Drosophila melanogaster, indicating that the reduction of PC is not associated with a high level of ethanol tolerance. 2. The phospholipid changes were not ethanol-specific. Larvae fed ethanol, n-butanol, isopropanol, methanol, and n-propanol exhibited similar changes. 3. At 200 mM concentrations, dietary ethanol acted as a competitive inhibitor for the larval uptake of dietary choline. At higher concentrations, dietary ethanol acted as a noncompetitive inhibitor. This ethanol-induced inhibition of dietary choline uptake can only partially explain the ethanol-induced reductions in larval PC.
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Affiliation(s)
- R R Miller
- Department of Biology, Knox College, Galesburg, IL 61401
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28
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McMaster CR, Choy PC. The determination of tissue ethanolamine levels by reverse-phase high-performance liquid chromatography. Lipids 1992; 27:560-3. [PMID: 1453887 DOI: 10.1007/bf02536140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A rapid and sensitive procedure for the determination of ethanolamine levels in mammalian tissues is reported. Ethanolamine was extracted from the tissue with a chloroform/methanol mixture, followed by phase separation. The aqueous phase was subjected to charcoal chromatography and the eluant was derivatized with phenylisothiocyanate. The amount of phenylthiocarbamyl (PTC) ethanolamine in the tissue extract was determined by reverse-phase high-performance liquid chromatography. Quantitation of PTC ethanolamine was linear between 0.1-1.0 nmol. The pool sizes of ethanolamine in hamster heart, liver and kidney were found to be 1.07, 0.92 and 1.11 mumol/g wet weight, respectively. The sensitivity of the method would allow the determination of ethanolamine in very small tissue samples.
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Affiliation(s)
- C R McMaster
- Department of Biochemistry and Molecular Biology, University of Manitoba, Winnipeg, Canada
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Sheff KY, Yorek MA, Long JP. Hemicholinium-3 derivatives A-4 and A-5 affect choline and acetylcholine metabolism. Eur J Pharmacol 1991; 206:105-12. [PMID: 2065716 DOI: 10.1016/0922-4106(91)90018-d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The neuroblastoma-glioma hybrid cell (NG108-15) has a sodium-dependent, high-affinity choline transport system with a Km of 16.0 +/- 3.4 microM and a Vmax of 214.5 +/- 27.7 pmol/min/mg protein. A-4, A-5 and HC-3 produce dose-dependent inhibition of high-affinity choline transport in NG108-15 cells. Following 24 h exposure to approximately the EC50 of each inhibitor, no significant decrease was found in total choline accumulation or in choline incorporation into phosphatidylcholine. However, when additional inhibitor was added during the 24 h incubation, significant decreases in choline accumulation were produced by A-4 and A-5. Following 24 h exposure to each compound, only A-4 was able to significantly affect free choline content. In contrast, each inhibitor was able to significantly decrease acetylcholine content following 24 h exposure. Possible reasons for consistent decreases in acetylcholine versus minimal changes in choline metabolism will be discussed.
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Affiliation(s)
- K Y Sheff
- Department of Pharmacology, College of Medicine, University of Iowa, Iowa City 52242
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Tijburg LB, Geelen MJ, van Golde LM. Regulation of the biosynthesis of triacylglycerol, phosphatidylcholine and phosphatidylethanolamine in the liver. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 1004:1-19. [PMID: 2663077 DOI: 10.1016/0005-2760(89)90206-3] [Citation(s) in RCA: 191] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- L B Tijburg
- Laboratory of Veterinary Biochemistry, University of Utrecht, The Netherlands
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Head Group Specificity in the Requirement of Phosphatidylcholine Biosynthesis for Very Low Density Lipoprotein Secretion from Cultured Hepatocytes. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)60474-0] [Citation(s) in RCA: 104] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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34
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Lipton BA, Yorek MA, Ginsberg BH. Ethanolamine and choline transport in cultured bovine aortic endothelial cells. J Cell Physiol 1988; 137:571-6. [PMID: 3192633 DOI: 10.1002/jcp.1041370325] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The transport of the polar head groups, ethanolamine and choline, was examined in cultured bovine aortic endothelial cells. Both ethanolamine and choline are taken up by high- and low-affinity systems. The K'm and V'max for the Na+-dependent, high-affinity ethanolamine and choline transport system are 3.0 and 3.0 microM and 5.4 and 7.3 pmol/mg protein/min, respectively. Ethanolamine and choline competitively influence one another's transport as the presence of 50 microM ethanolamine increases the K'm but not the V'max of choline uptake. Likewise, 50 microM choline increases the K'm but not the V'max of ethanolamine transport. The concentration of ethanolamine that inhibits maximal velocity of 5 microM choline by 50% is 9.7 microM, while 12 microM choline inhibits 5 microM ethanolamine maximal velocity by 50%. Uptake of both head groups is only partially Na+-dependent and is inhibited similarly by 2-methylethanolamine and 2,2-dimethylethanolamine at all concentrations examined. Hemicholinium-3, a classic inhibitor of high-affinity, Na+-dependent choline transport, reduces both ethanolamine and choline accumulation in a concentration-dependent fashion, but has a greater effect on choline transport at higher concentrations. The major portion of these data is consistent with our hypothesis that the uptake of physiological concentrations of ethanolamine and choline may occur through the same transport system. However, the results of the effect of hemicholinium-3 and the extent of Na+-dependency of choline and ethanolamine uptake could be interpreted as meaning that separate transport systems for choline and ethanolamine exist which cross react or that a single transport system exists which has separate active sites for the two compounds.
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Affiliation(s)
- B A Lipton
- Department of Biochemistry, Veterans Administration Medical Center, Iowa City, Iowa 52240
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