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Wu J, Li Z, Zhu H, Chang Y, Li Q, Chen J, Shen G, Feng J. Childhood overweight and obesity: age stratification contributes to the differences in metabolic characteristics. Obesity (Silver Spring) 2024; 32:571-582. [PMID: 38112246 DOI: 10.1002/oby.23964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 10/11/2023] [Accepted: 11/06/2023] [Indexed: 12/21/2023]
Abstract
OBJECTIVE The aim of this study was to identify the differential metabolic characteristics of children with overweight and obesity and understand their potential mechanism in different age stratifications. METHODS Four hundred seventy-three children were recruited and divided into two age stratifications: >4 years (older children) and ≤4 years (younger children), and overweight and obesity were defined according to their BMI percentile. A one dimensional proton nuclear magnetic resonance (1 H-NMR)-based metabolomics strategy combined with pattern recognition methods was used to identify the metabolic characteristics of childhood overweight and obesity. RESULTS Four and sixteen potential biomarkers related to overweight and two and twenty potential biomarkers related to obesity were identified from younger and older children, respectively. Fluctuations in phenylalanine, tyrosine, glutamine, leucine, histidine, and ascorbate co-occurred in children with obesity at two age stratifications. The disturbances in biosynthesis and metabolism of amino acids, lipid metabolism, and galactose metabolism disturbance were mainly involved in children with overweight and obesity. CONCLUSIONS The metabolic disturbances show a significant progression from overweight to obesity in children, and different metabolic characteristics were demonstrated in age stratifications. The changes in the levels of phenylalanine, tyrosine, glutamine, leucine, histidine, and ascorbate were tracked with the persistence of childhood obesity. These findings will promote the mechanistic understanding of childhood overweight and obesity.
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Affiliation(s)
- Jinxia Wu
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China
| | - Zhenchang Li
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China
| | - Hongwei Zhu
- Department of Pediatrics, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui, China
| | - Yajie Chang
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China
| | - Quanquan Li
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China
| | - Jing Chen
- Department of Child Health, Women and Children's Hospital, School of Medicine, Xiamen University, Xiamen, China
| | - Guiping Shen
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China
| | - Jianghua Feng
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China
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2
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Gwanyanya A, Godsmark CN, Kelly-Laubscher R. Ethanolamine: A Potential Promoiety with Additional Effects in the Brain. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2020; 21:108-117. [PMID: 33319663 DOI: 10.2174/1871527319999201211204645] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 08/14/2020] [Accepted: 09/11/2020] [Indexed: 11/22/2022]
Abstract
Ethanolamine is a bioactive molecule found in several cells, including those in the central nervous system (CNS). In the brain, ethanolamine and ethanolamine-related molecules have emerged as prodrug moieties that can promote drug movement across the blood-brain barrier. This improvement in the ability to target drugs to the brain may also mean that in the process ethanolamine concentrations in the brain are increased enough for ethanolamine to exert its own neurological ac-tions. Ethanolamine and its associated products have various positive functions ranging from cell signaling to molecular storage, and alterations in their levels have been linked to neurodegenerative conditions such as Alzheimer's disease. This mini-review focuses on the effects of ethanolamine in the CNS and highlights the possible implications of these effects for drug design.
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Affiliation(s)
- Asfree Gwanyanya
- Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town,. South Africa
| | - Christie Nicole Godsmark
- School of Public Health, College of Medicine and Health, University College Cork, Cork,. Ireland
| | - Roisin Kelly-Laubscher
- Department of Pharmacology and Therapeutics, School of Medicine, College of Medicine and Health, University College Cork, Cork,. Ireland
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3
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Rodriguez-Cuenca S, Pellegrinelli V, Campbell M, Oresic M, Vidal-Puig A. Sphingolipids and glycerophospholipids - The "ying and yang" of lipotoxicity in metabolic diseases. Prog Lipid Res 2017; 66:14-29. [PMID: 28104532 DOI: 10.1016/j.plipres.2017.01.002] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 11/30/2016] [Accepted: 01/05/2017] [Indexed: 12/14/2022]
Abstract
Sphingolipids in general and ceramides in particular, contribute to pathophysiological mechanisms by modifying signalling and metabolic pathways. Here, we present the available evidence for a bidirectional homeostatic crosstalk between sphingolipids and glycerophospholipids, whose dysregulation contributes to lipotoxicity induced metabolic stress. The initial evidence for this crosstalk originates from simulated models designed to investigate the biophysical properties of sphingolipids in plasma membrane representations. In this review, we reinterpret some of the original findings and conceptualise them as a sort of "ying/yang" interaction model of opposed/complementary forces, which is consistent with the current knowledge of lipid homeostasis and pathophysiology. We also propose that the dysregulation of the balance between sphingolipids and glycerophospholipids results in a lipotoxic insult relevant in the pathophysiology of common metabolic diseases, typically characterised by their increased ceramide/sphingosine pools.
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Affiliation(s)
- S Rodriguez-Cuenca
- Metabolic Research Laboratories, Wellcome Trust MRC Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge. Cambridge, UK.
| | - V Pellegrinelli
- Metabolic Research Laboratories, Wellcome Trust MRC Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge. Cambridge, UK
| | - M Campbell
- Metabolic Research Laboratories, Wellcome Trust MRC Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge. Cambridge, UK
| | - M Oresic
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, FI -20520 Turku, Finland
| | - A Vidal-Puig
- Metabolic Research Laboratories, Wellcome Trust MRC Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge. Cambridge, UK; Wellcome Trust Sanger Institute, Hinxton, UK.
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Matas D, Juknat A, Pietr M, Klin Y, Vogel Z. Anandamide protects from low serum-induced apoptosis via its degradation to ethanolamine. J Biol Chem 2007; 282:7885-92. [PMID: 17227767 DOI: 10.1074/jbc.m608646200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Anandamide (AEA) is a lipid molecule belonging to the family of endocannabinoids. Various studies report neuroprotective activity of AEA against toxic insults, such as ischemic conditions and excitotoxicity, whereas some show that AEA has pro-apoptotic effects. Here we have shown that AEA confers a protective activity in N18TG2 murine neuroblastoma cells subjected to low serum-induced apoptosis. We have demonstrated that the protection from apoptosis by AEA is not mediated via the CB1 receptor, the CB2 receptor, or the vanilloid receptor 1. Interestingly, breakdown of AEA by fatty acid amide hydrolase is required for the protective effect of AEA. Furthermore, the ethanolamine (EA) generated in this reaction is the metabolite responsible for the protective response. The elevation in the levels of reactive oxygen species during low serum-induced apoptosis is not affected by AEA or EA. On the other hand, AEA and EA reduce caspase 3/7 activity, and AEA attenuates the cleavage of PARP-1. Taken together, our results demonstrate a role for AEA and EA in the protection against low serum-induced apoptosis.
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Affiliation(s)
- Devorah Matas
- Department of Neurobiology, Weizmann Institute of Science, 76100 Rehovot, Israel
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5
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Abstract
Phospholipase D catalyses the hydrolysis of the phosphodiester bond of glycerophospholipids to generate phosphatidic acid and a free headgroup. Phospholipase D activities have been detected in simple to complex organisms from viruses and bacteria to yeast, plants, and mammals. Although enzymes with broader selectivity are found in some of the lower organisms, the plant, yeast, and mammalian enzymes are selective for phosphatidylcholine. The two mammalian phospholipase D isoforms are regulated by protein kinases and GTP binding proteins of the ADP-ribosylation and Rho families. Mammalian and yeast phospholipases D are also potently stimulated by phosphatidylinositol 4,5-bisphosphate. This review discusses the identification, characterization, structure, and regulation of phospholipase D. Genetic and pharmacological approaches implicate phospholipase D in a diverse range of cellular processes that include receptor signaling, control of intracellular membrane transport, and reorganization of the actin cytoskeleton. Most ideas about phospholipase D function consider that the phosphatidic acid product is an intracellular lipid messenger. Candidate targets for phospholipase-D-generated phosphatidic acid include phosphatidylinositol 4-phosphate 5-kinases and the raf protein kinase. Phosphatidic acid can also be converted to two other lipid mediators, diacylglycerol and lyso phosphatidic acid. Coordinated activation of these phospholipase-D-dependent pathways likely accounts for the pleitropic roles for these enzymes in many aspects of cell regulation.
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Affiliation(s)
- Mark McDermott
- Department of Cell and Developmental Biology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, 27599-7090, USA
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Meacci E, Nuti F, Catarzi S, Vasta V, Donati C, Bourgoin S, Bruni P, Moss J, Vaughan M. Activation of phospholipase D by bradykinin and sphingosine 1-phosphate in A549 human lung adenocarcinoma cells via different GTP-binding proteins and protein kinase C delta signaling pathways. Biochemistry 2003; 42:284-92. [PMID: 12525155 DOI: 10.1021/bi026350a] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Phospholipase D (PLD) is involved in the signaling by many extracellular ligands, and its regulation appears to be quite complex. We investigated the signaling pathways initiated by bradykinin (BK) or sphingosine 1-phosphate (S1P) in A549 cells to define molecular mechanisms responsible for their additive effects on PLD activity. BK and S1P each elicited a sustained increase in phosphatidic acid content through a rapid and transient activation of PLD. The two pathways demonstrated rapid homologous downregulation, but heterologous desensitization was not observed. Action of both agonists required protein kinase C (PKC) activation and Ca(2+) influx but was mediated by different heterotrimeric G proteins. In membranes, inhibition of PKCdelta by rottlerin enhanced BK activation of PLD but inhibited that by S1P. Rottlerin inhibited activation of PLD in nuclei by both BK and S1P. By in situ immunofluorescence or cell fractionation followed by immunoblotting, PLD1 was concentrated primarily in nuclei, whereas the membrane fraction contained PLD2 and PLD1. Moreover, PKCdelta specifically phosphorylated recombinant PLD2, but not PLD1. BK and S1P similarly enhanced RhoA translocation to nuclei, whereas BK was less efficacious than S1P on RhoA relocalization to membranes. Effects of both agonists on the nuclear fraction, which contains only PLD1, are compatible with a RhoA- and PKCdelta-dependent process. In membranes, which contain both PLD1 and PLD2, the stimulatory effect of S1P on PLD activity can best be explained by RhoA- and PKCdelta-dependent activation of PLD1; in contrast, the effects of BK on RhoA translocation and enhancement of BK-stimulated PLD activity by PKC inhibition are both consistent with PLD2 serving as its primary target.
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Affiliation(s)
- Elisabetta Meacci
- Dipartimento di Scienze Biochimiche, Università di Firenze, Viale G.B. Morgagni 50, 50134 Firenze, Italy
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Ajioka I, Akaike T, Watanabe Y. Ethanolamine is a co-mitogenic factor for proliferation of primary hepatocytes. J Cell Biochem 2002; 84:249-63. [PMID: 11787054 DOI: 10.1002/jcb.10012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Mature adult parenchymal hepatocytes can enter the S phase in the presence of growth factors such as HGF and EGF, but rarely proliferate in culture. We hypothesized that the cell cycle of hepatocytes in culture is restricted before G(2)/M phase and we attempted to identify the factor that induces cell cycle progression. We found that the conditioned medium from long-term cultured hepatocytes contained co-mitogenic activity with other growth factors, which was attributed to ethanolamine (Etn). Etn induced not only DNA synthesis but also cell replication of cultured hepatocytes with various other growth factors. Etn and HGF synergistically induced cyclin D(1), A and B expression, however, only cyclin B but not cyclin A formed a complex with Cdc2. In addition, Etn combined with HGF enhanced PKCbetaII expression and translocated PKCbetaII to the plasma membrane, and induced filopodia formation, which was inhibited by an antisense oligonucleotide against PKCbetaII. In addition, blocking the cytoskeleton rearrangement with inhibitors (colchicine, cytochalasin D, or chlerythrine (a specific PKC inhibitor)) inhibited cyclin expression and cell proliferation. Although Etn enhanced the downstream product, cellular phosphatidylethanolamine (PE), PE itself did not show any Etn-like activities on hepatocytes. Taken together, our results indicate that Etn functions as a co-replication factor to promote the cell cycle of mature hepatocytes to G(2)/M phase in the presence of growth factors. The activity is thought to be mediated by PKCbetaII-dependent cyclin B expression.
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Affiliation(s)
- Itsuki Ajioka
- Department of Biomolecular Engineering, Tokyo Institute of Technology, 4259 Nagatsuda, Midori-ku, Yokohama 226-8501, Japan
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8
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Abstract
Sphingosine 1-phosphate is formed in cells in response to diverse stimuli, including growth factors, cytokines, G-protein-coupled receptor agonists, antigen, etc. Its production is catalysed by sphingosine kinase, while degradation is either via cleavage to produce palmitaldehyde and phosphoethanolamine or by dephosphorylation. In this review we discuss the most recent advances in our understanding of the role of the enzymes involved in metabolism of this lysolipid. Sphingosine 1-phosphate can also bind to members of the endothelial differentiation gene (EDG) G-protein-coupled receptor family [namely EDG1, EDG3, EDG5 (also known as H218 or AGR16), EDG6 and EDG8] to elicit biological responses. These receptors are coupled differentially via G(i), G(q), G(12/13) and Rho to multiple effector systems, including adenylate cyclase, phospholipases C and D, extracellular-signal-regulated kinase, c-Jun N-terminal kinase, p38 mitogen-activated protein kinase and non-receptor tyrosine kinases. These signalling pathways are linked to transcription factor activation, cytoskeletal proteins, adhesion molecule expression, caspase activities, etc. Therefore sphingosine 1-phosphate can affect diverse biological responses, including mitogenesis, differentiation, migration and apoptosis, via receptor-dependent mechanisms. Additionally, sphingosine 1-phosphate has been proposed to play an intracellular role, for example in Ca(2+) mobilization, activation of non-receptor tyrosine kinases, inhibition of caspases, etc. We review the evidence for both intracellular and extracellular actions, and extensively discuss future approaches that will ultimately resolve the question of dual action. Certainly, sphingosine 1-phosphate will prove to be unique if it elicits both extra- and intra-cellular actions. Finally, we review the evidence that implicates sphingosine 1-phosphate in pathophysiological disease states, such as cancer, angiogenesis and inflammation. Thus there is a need for the development of new therapeutic compounds, such as receptor antagonists. However, identification of the most suitable targets for drug intervention requires a full understanding of the signalling and action profile of this lysosphingolipid. This article describes where the research field is in relation to achieving this aim.
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Affiliation(s)
- S Pyne
- Department of Physiology and Pharmacology, Strathclyde Institute for Biomedical Sciences, University of Strathclyde, 27 Taylor Street, Glasgow G4 ONR, Scotland, UK.
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9
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Windh RT, Lee MJ, Hla T, An S, Barr AJ, Manning DR. Differential coupling of the sphingosine 1-phosphate receptors Edg-1, Edg-3, and H218/Edg-5 to the G(i), G(q), and G(12) families of heterotrimeric G proteins. J Biol Chem 1999; 274:27351-8. [PMID: 10488065 DOI: 10.1074/jbc.274.39.27351] [Citation(s) in RCA: 269] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sphingosine 1-phosphate (S1P) is one of several bioactive phospholipids that exert profound mitogenic and morphogenic actions. Originally characterized as a second messenger, S1P is now recognized to achieve many of its effects through cell surface, G protein-coupled receptors. We used a subunit-selective [(35)S]GTPgammaS binding assay to investigate whether the variety of actions exerted through Edg-1, a recently identified receptor for S1P, might be achieved through multiple G proteins. We found, employing both Sf9 and HEK293 cells, that Edg-1 activates only members of the G(i) family, and not G(s), G(q), G(12), or G(13). We additionally established that Edg-1 activates G(i) in response not only to S1P but also sphingosylphosphorylcholine; no effects of lysophosphatidic acid through Edg-1 were evident. Our assays further revealed a receptor(s) for S1P endogenous to HEK293 cells that mediates activation of G(13) as well as G(i). Because several of the biological actions of S1P are assumed to proceed through the G(12/13) family, we tested whether Edg-3 and H218/Edg-5, two other receptors for S1P, might have a broader coupling profile than Edg-1. Indeed, Edg-3 and H218/Edg-5 communicate not only with G(i) but also with G(q) and G(13). These studies represent the first characterization of S1P receptor activity through G proteins directly and establish fundamental differences in coupling.
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Affiliation(s)
- R T Windh
- Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
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10
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Banno Y, Fujita H, Ono Y, Nakashima S, Ito Y, Kuzumaki N, Nozawa Y. Differential phospholipase D activation by bradykinin and sphingosine 1-phosphate in NIH 3T3 fibroblasts overexpressing gelsolin. J Biol Chem 1999; 274:27385-91. [PMID: 10488069 DOI: 10.1074/jbc.274.39.27385] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Gelsolin, an actin-binding protein, shows a strong ability to bind to phosphatidylinositol 4,5-bisphosphate (PIP(2)). Here we showed in in vitro experiments that gelsolin inhibited recombinant phospholipase D1 (PLD1) and PLD2 activities but not the oleate-dependent PLD and that this inhibition was not reversed by increasing PIP(2) concentration. To investigate the role of gelsolin in agonist-mediated PLD activation, we used NIH 3T3 fibroblasts stably transfected with the cDNA for human cytosolic gelsolin. Gelsolin overexpression suppressed bradykinin-induced activation of phospholipase C (PLC) and PLD. On the other hand, sphingosine 1-phosphate (S1P)-induced PLD activation could not be modified by gelsolin overexpression, whereas PLC activation was suppressed. PLD activation by phorbol myristate acetate or Ca(2+) ionophore A23187 was not affected by gelsolin overexpression. Stimulation of control cells with either bradykinin or S1P caused translocation of protein kinase C (PKC) to the membranes. Translocation of PKC-alpha and PKC-beta1 but not PKC-epsilon was reduced in gelsolin-overexpressed cells, whereas phosphorylation of mitogen-activated protein kinase was not changed. S1P-induced PLC activation and mitogen-activated protein kinase phosphorylation were sensitive to pertussis toxin, but PLD response was insensitive to such treatment, suggesting that S1P induced PLD activation via certain G protein distinct from G(i) for PLC and mitogen-activated protein kinase pathway. Our results suggest that gelsolin modulates bradykinin-mediated PLD activation via suppression of PLC and PKC activities but did not affect S1P-mediated PLD activation.
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Affiliation(s)
- Y Banno
- Department of Biochemistry, Gifu University School of Medicine, Tsukasamachi-40, Gifu 500-8705, Japan
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Meacci E, Vasta V, Donati C, Farnararo M, Bruni P. Receptor-mediated activation of phospholipase D by sphingosine 1-phosphate in skeletal muscle C2C12 cells. A role for protein kinase C. FEBS Lett 1999; 457:184-8. [PMID: 10471775 DOI: 10.1016/s0014-5793(99)01033-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The present study showed that sphingosine 1-phosphate (SPP) induced rapid stimulation of phospholipase D (PLD) in skeletal muscle C2C12 cells. The effect was receptor-mediated since it was fully inhibited by pertussis toxin. All known SPP-specific receptors, Edg-1, Edg-3 and AGR16/H218, resulted to be expressed in C2C12 myoblasts, although at a different extent. SPP-induced PLD activation did not involve membrane translocation of PLD1 or PLD2 and appeared to be fully dependent on protein kinase C (PKC) catalytic activity. SPP increased membrane association of PKCalpha, PKCdelta and PKClambda, however, only PKCalpha and PKCdelta played a role in PLD activation since low concentrations of GF109203X and rottlerin, a selective inhibitor of PKCdelta, prevented PLD stimulation.
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Affiliation(s)
- E Meacci
- Dipartimento di Scienze Biochimiche, University of Florence, Viale G. B. Morgagni 50, 50134, Firenze, Italy.
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12
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Bladergroen BA, Bussière M, Klein W, Geelen MJ, Van Golde LM, Houweling M. Inhibition of phosphatidylcholine and phosphatidylethanolamine biosynthesis in rat-2 fibroblasts by cell-permeable ceramides. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 264:152-60. [PMID: 10447683 DOI: 10.1046/j.1432-1327.1999.00589.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Phospholipids and sphingolipids are important precursors of lipid-derived second messengers such as diacylglycerol and ceramide, which participate in several signal transduction pathways and in that way mediate the effects of various agonists. The cross-talk between glycerophospholipid and sphingolipid metabolism was investigated by examining the effects of cell-permeable ceramides on phosphatidylcholine (PtdCho) and phosphatidylethanolamine (PtdEtn) synthesis in Rat-2 fibroblasts. Addition of short-chain C6-ceramide to the cells resulted in a dose- and time-dependent inhibition of the CDP-pathways for PtdCho and PtdEtn synthesis. Treatment of cells for 4 h with 50 microM C6-ceramide caused an 83% and a 56% decrease in incorporation of radiolabelled choline and ethanolamine into PtdCho and PtdEtn, respectively. Exposure of the cells for longer time-periods (>/= 16 h) to 50 microM C6-ceramide resulted in apoptosis. The structural analogue dihydro-C6-ceramide did not affect PtdCho and PtdEtn synthesis. In pulse-chase experiments, radioactive choline and ethanolamine accumulated in CDP-choline and CDP-ethanolamine under the influence of C6-ceramide, suggesting that synthesis of both PtdCho and PtdEtn were inhibited at the final step in the CDP-pathways. Indeed, cholinephosphotransferase and ethanolaminephosphotransferase activities in membrane fractions from C6-ceramide-treated cells were reduced by 64% and 43%, respectively, when compared with control cells. No changes in diacylglycerol mass levels or synthesis of diacylglycerol from radiolabelled palmitate were observed. It was concluded that C6-ceramide affected glycerophospholipid synthesis predominantly by inhibition of the step in the CDP-pathways catalysed by cholinephosphotransferase and ethanolaminephosphotransferase.
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Affiliation(s)
- B A Bladergroen
- Department of Biochemistry and Cell Biology, Graduate School of Animal Health, Utrecht University, The Netherlands
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13
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Abstract
Many recent observations implicate choline and ethanolamine kinases as well as phosphatidylcholine-specific phospholipase C in the regulation of mitogenesis and carcinogenesis. For example, human cancers generally contain high concentrations of phosphoethanolamine and phosphocholine, and in different cell lines various growth factors, cytokines, oncogenes and chemical carcinogens were all shown to stimulate the formation of phosphocholine and phosphoethanolamine. In addition, other reports have appeared showing that both extracellular and intracellular phosphocholine as well as ethanolamine and its derivatives can regulate cell growth. This area of research has clearly arrived at a stage when it becomes important to examine critically the feasibility of water-soluble phospholipid intermediates serving as potential regulators of cell growth in vivo. Accordingly, the goal of this review is to summarise available information relating to the formation and mitogenic actions of intracellular and extracellular phosphocholine as well as ethanolamine and its derivatives.
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Affiliation(s)
- Z Kiss
- The Hormel Institute, University of Minnesota, Austin 55912, USA.
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14
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Kiss Z, Petrovics G, Olàh Z, Lehel C, Anderson WB. Overexpression of protein kinase C-epsilon and its regulatory domains in fibroblasts inhibits phorbol ester-induced phospholipase D activity. Arch Biochem Biophys 1999; 363:121-8. [PMID: 10049506 DOI: 10.1006/abbi.1998.1066] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In fibroblasts, the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA) stimulates phospholipase D (PLD)-mediated hydrolysis of both phosphatidylcholine (PtdCho) and phosphatidylethanolamine (PtdEtn) by PKC-alpha-mediated nonphosphorylating and phosphorylating mechanisms. Here we have used NIH 3T3 fibroblasts overexpressing holo PKC-epsilon and its regulatory, catalytic, and zinc finger domain fragments to determine if this isozyme also regulates PLD activity. Overexpression of holo PKC-epsilon inhibited the stimulatory effects of PMA (5-100 nM) on both PtdCho and PtdEtn hydrolysis. Overexpression of PKC-epsilon also was found to inhibit platelet-derived growth factor-induced PLD activity. Expression of the catalytic unit of PKC-epsilon had no effect on PMA-induced PLD activity. In contrast, expression of both the regulatory domain fragment and the zinc finger domain of PKC-epsilon resulted in significant inhibition of PMA-stimulated PtdCho and PtdEtn hydrolysis. Interestingly, although PKC-alpha also mediates the stimulatory effect of PMA on the synthesis of PtdCho by a phosphorylation mechanism, overexpression of holo PKC-epsilon or its regulatory domain fragments did not affect PMA-induced PtdCho synthesis. These results indicate that the PKC-epsilon system can act as a negative regulator of PLD activity and that this inhibition is mediated by its regulatory domain.
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Affiliation(s)
- Z Kiss
- The Hormel Institute, University of Minnesota, Austin, Minnesota, 55912, USA.
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