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García del Caño G, Aretxabala X, González-Burguera I, Montaña M, López de Jesús M, Barrondo S, Barrio RJ, Sampedro C, Goicolea MA, Sallés J. Nuclear diacylglycerol lipase-α in rat brain cortical neurons: evidence of 2-arachidonoylglycerol production in concert with phospholipase C-β activity. J Neurochem 2014; 132:489-503. [PMID: 25308538 DOI: 10.1111/jnc.12963] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 09/22/2014] [Accepted: 10/07/2014] [Indexed: 01/12/2023]
Abstract
In this report, we describe the localization of diacylglycerol lipase-α (DAGLα) in nuclei from adult cortical neurons, as assessed by double-immunofluorescence staining of rat brain cortical sections and purified intact nuclei and by western blot analysis of subnuclear fractions. Double-labeling assays using the anti-DAGLα antibody and NeuN combined with Hoechst staining showed that only nuclei of neuronal origin were DAGLα positive. At high resolution, DAGLα-signal displayed a punctate pattern in nuclear subdomains poor in Hoechst's chromatin and lamin B1 staining. In contrast, SC-35- and NeuN-signals (markers of the nuclear speckles) showed a high overlap with DAGLα within specific subdomains of the nuclear matrix. Among the members of the phospholipase C-β (PLCβ) family, PLCβ1, PLCβ2, and PLCβ4 exhibited the same distribution with respect to chromatin, lamin B1, SC-35, and NeuN as that described for DAGLα. Furthermore, by quantifying the basal levels of 2-arachidonoylglycerol (2-AG) by liquid chromatography and mass spectrometry (LC-MS), and by characterizing the pharmacology of its accumulation, we describe the presence of a mechanism for 2-AG production, and its PLCβ/DAGLα-dependent biosynthesis in isolated nuclei. These results extend our knowledge about subcellular distribution of neuronal DAGLα, providing biochemical grounds to hypothesize a role for 2-AG locally produced within the neuronal nucleus.
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Affiliation(s)
- Gontzal García del Caño
- Departamento de Neurociencias, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 01006 Vitoria-Gasteiz (Araba), Spain
| | - Xabier Aretxabala
- Departamento de Neurociencias, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 01006 Vitoria-Gasteiz (Araba), Spain
| | - Imanol González-Burguera
- Departamento de Farmacología, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 01006 Vitoria-Gasteiz (Araba), Spain
| | - Mario Montaña
- Departamento de Farmacología, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 01006 Vitoria-Gasteiz (Araba), Spain
| | - Maider López de Jesús
- Departamento de Farmacología, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 01006 Vitoria-Gasteiz (Araba), Spain
| | - Sergio Barrondo
- Departamento de Farmacología, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 01006 Vitoria-Gasteiz (Araba), Spain
| | - Ramón J Barrio
- Departamento de Química Analítica, Facultad de Farmacia, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 01006 Vitoria-Gasteiz (Araba), Spain
| | - Carmen Sampedro
- Servicio General de Análisis, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 01006 Vitoria-Gasteiz (Araba), Spain
| | - M Arantzazu Goicolea
- Departamento de Química Analítica, Facultad de Farmacia, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 01006 Vitoria-Gasteiz (Araba), Spain
| | - Joan Sallés
- Departamento de Farmacología, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 01006 Vitoria-Gasteiz (Araba), Spain
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Alvite G, Garrido N, Kun A, Paulino M, Esteves A. Towards an understanding of Mesocestoides vogae fatty acid binding proteins' roles. PLoS One 2014; 9:e111204. [PMID: 25347286 PMCID: PMC4210247 DOI: 10.1371/journal.pone.0111204] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 09/29/2014] [Indexed: 01/24/2023] Open
Abstract
Two fatty acid binding proteins, MvFABPa and MvFABPb were identified in the parasite Mesocestoides vogae (Platyhelmithes, Cestoda). Fatty acid binding proteins are small intracellular proteins whose members exhibit great diversity. Proteins of this family have been identified in many organisms, of which Platyhelminthes are among the most primitive. These proteins have particular relevance in flatworms since de novo synthesis of fatty acids is absent. Fatty acids should be captured from the media needing an efficient transport system to uptake and distribute these molecules. While HLBPs could be involved in the shuttle of fatty acids to the surrounding host tissues and convey them into the parasite, FABPs could be responsible for the intracellular trafficking. In an effort to understand the role of MvFABPs in fatty acid transport of M. vogae larvae, we analysed the intracellular localization of both MvFABPs and the co-localization with in vivo uptake of fatty acid analogue BODIPY FL C16. Immunohistochemical studies on larvae sections using specific antibodies, showed a diffuse cytoplasmic distribution of each protein with some expression in nuclei and mitochondria. MvFABPs distribution was confirmed by mass spectrometry identification from 2D-electrophoresis of larvae subcellular fractions. This work is the first report showing intracellular distribution of MvFABPs as well as the co-localization of these proteins with the BODIPY FL C16 incorporated from the media. Our results suggest that fatty acid binding proteins could target fatty acids to cellular compartments including nuclei. In this sense, M. vogae FABPs could participate in several cellular processes fulfilling most of the functions attributed to vertebrate's counterparts.
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Affiliation(s)
- Gabriela Alvite
- Sección Bioquímica, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Natalia Garrido
- Sección Bioquímica, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Alejandra Kun
- Sección Bioquímica, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
- Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Margot Paulino
- Centro de Bioinformática Estructural-DETEMA, Facultad de Química, Universidad de la República, Montevideo, Uruguay
| | - Adriana Esteves
- Sección Bioquímica, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
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3
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García del Caño G, Montaña M, Aretxabala X, González-Burguera I, López de Jesús M, Barrondo S, Sallés J. Nuclear phospholipase C-β1 and diacylglycerol LIPASE-α in brain cortical neurons. Adv Biol Regul 2014; 54:12-23. [PMID: 24076015 DOI: 10.1016/j.jbior.2013.09.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 09/03/2013] [Accepted: 09/03/2013] [Indexed: 06/02/2023]
Abstract
Phosphoinositide (PtdIns) signaling involves the generation of lipid second messengers in response to stimuli in a receptor-mediated manner at the plasma membrane. In neuronal cells of adult brain, the standard model proposes that activation of metabotropic receptors coupled to Phospholipase C-β1 (PLC-β1) is linked to endocannabinoid signaling through the production of diacylglycerol (DAG), which could be systematically metabolized by 1,2-diacylglycerol Lipases (DAGL) to produce an increase of 2-arachidonoyl-glycerol (2-AG), the most abundant endocannabinoid in the brain. However, the existence of a nuclear PtdIns metabolism independent from that occurring elsewhere in the cell is now widely accepted, suggesting that the nucleus constitutes both a functional and a distinct compartment for PtdIns metabolism. In this review, we shall highlight the main achievements in the field of neuronal nuclear inositol lipid metabolism with particular attention to progress made linked to the 2-AG biosynthesis. Our aim has been to identify potential sites of 2-AG synthesis other than the neuronal cytoplasmic compartment by determining the subcellular localization of PLC-β1 and DAGL-α, which is much more abundant than DAGL-β in brain. Our data show that PLC-β1 and DAGL-α are detected in discrete brain regions, with a marked predominance of pyramidal morphologies of positive cortical cells, consistent with their role in the biosynthesis and release of 2-AG by pyramidal neurons to control their synaptic inputs. However, as novelty, we showed here an integrated description of the localization of PLC-β1 and DAGL-α in the neuronal nuclear compartment. We discuss our comparative analysis of the expression patterns of PLC-β1 and DAGL-α, providing some insight into the potential autocrine role of 2-AG production in the neuronal nuclear compartment that probably subserve additional roles to the recognized activation of the CB1 cannabinoid receptor.
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Affiliation(s)
- Gontzal García del Caño
- Departamento de Neurociencias, Facultad de Farmacia (Vitoria-Gasteiz), Universidad del País Vasco (UPV/EHU), Spain
| | - Mario Montaña
- Departamento de Farmacología, Facultad de Farmacia (Vitoria-Gasteiz), Universidad del País Vasco (UPV/EHU), Spain; CIBERSAM, Spain
| | - Xabier Aretxabala
- Departamento de Neurociencias, Facultad de Farmacia (Vitoria-Gasteiz), Universidad del País Vasco (UPV/EHU), Spain
| | - Imanol González-Burguera
- Departamento de Farmacología, Facultad de Farmacia (Vitoria-Gasteiz), Universidad del País Vasco (UPV/EHU), Spain
| | - Maider López de Jesús
- Departamento de Farmacología, Facultad de Farmacia (Vitoria-Gasteiz), Universidad del País Vasco (UPV/EHU), Spain; CIBERSAM, Spain
| | - Sergio Barrondo
- Departamento de Farmacología, Facultad de Farmacia (Vitoria-Gasteiz), Universidad del País Vasco (UPV/EHU), Spain; CIBERSAM, Spain
| | - Joan Sallés
- Departamento de Farmacología, Facultad de Farmacia (Vitoria-Gasteiz), Universidad del País Vasco (UPV/EHU), Spain; CIBERSAM, Spain.
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Maté SM, Layerenza JP, Ves-Losada A. Arachidonic acid pools of rat kidney cell nuclei. Mol Cell Biochem 2010; 345:259-70. [DOI: 10.1007/s11010-010-0580-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Accepted: 08/28/2010] [Indexed: 11/29/2022]
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The presence of a secretory phospholipase A2 in the nuclei of neuronal and glial cells of rat brain cortex. Biochim Biophys Acta Mol Cell Biol Lipids 2007; 1771:1345-52. [DOI: 10.1016/j.bbalip.2007.08.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2007] [Revised: 08/09/2007] [Accepted: 08/10/2007] [Indexed: 01/22/2023]
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Abstract
Lipids are not only components of cell nucleus membranes, but are also found in the membrane-depleted nuclei where they fulfill special functions. We have investigated the lipid composition of membrane-depleted rat liver nuclei obtained by incubation with low Triton X-100 concentrations of 0.04% and 0.08%, which rendered them unaltered or hardly altered. Under these conditions, 26% of proteins and 22% of phospholipids were recovered. The main phospholipids were phosphatidylcholine > phosphatidylethanolamine > phosphatidylinositol = or > phosphatidylserine and sphingomyelin (in decreasing concentrations). The fatty acid components of total lipids and phosphatidylcholine were mainly unsaturated. Over 40% belonged to the n-6 series (arachidonic > or = 25% and linoleic 15%); approximately 40% corresponded to saturated acids and <10% were monoenoic. Endonuclear phosphatidylcholine was built up by 16 molecular species, the most abundant being 18:0-20:4 (32%), 16:0-20:4 (19%), 16:0-18:2 (13%), and 18:0-18:2 (11%). The fatty acid composition and phosphatidylcholine molecular species distribution in the membrane-depleted nucleus of rat liver showed patterns similar to the whole nucleus, mitochondria, microsomes, and homogenate of the parent liver cells, suggesting that endonuclear lipid pool composition is mainly determined by a liver organ profile.
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Affiliation(s)
- Sabina M Maté
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), Facultad de Ciencias Médicas, UNLP-CONICET, calles 60 y 120, Argentina
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7
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Gayral S, Déléris P, Laulagnier K, Laffargue M, Salles JP, Perret B, Record M, Breton-Douillon M. Selective activation of nuclear phospholipase D-1 by g protein-coupled receptor agonists in vascular smooth muscle cells. Circ Res 2006; 99:132-9. [PMID: 16778131 DOI: 10.1161/01.res.0000232323.86227.8b] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Recent studies highlight the existence of an autonomous nuclear lipid metabolism related to cellular proliferation. However, the importance of nuclear phosphatidylcholine (PC) metabolism is poorly understood. Therefore, we were interested in nuclear PCs as a source of second messengers and, particularly, nuclear phospholipase D (PLD) identification in membrane-free nuclei isolated from pig aorta vascular smooth muscle cells (VSMCs). Using immunoblot experiment, in vitro PLD assay with fluorescent substrate and confocal microscopy analysis, we demonstrated that only PLD1 is expressed in VSMC nucleus, whereas PLD1 and PLD2 are present in VSMC. Inhibition of RhoA and protein kinase Czeta (PKCzeta) by C3-exoenzyme and PKCzeta pseudosubstrate inhibitor, respectively, conducted a decrease of phosphatidylethanol production. On the other hand, treatment of intact VSMCs, but not nuclei, with phosphoinositide 3-kinase (PI3K) inhibitors prevented partially nuclear PLD1 activity, indicating for the first time that PI3K may have a role in nuclear PLD regulation. In addition, lysophosphatidic acid (LPA) or angiotensin II treatment of VSMCs resulted in an increase of intranuclear PLD activity, whereas platelet-derived growth factor and epidermal growth factor have no significant effect. Moreover, pertussis toxin induced a decrease of LPA-stimulated nuclear PLD1 activity, suggesting that heterotrimeric G(i)/G(0) protein involvement in intranuclear PLD1 regulation. We also show that LPA-induced nuclear PLD1 activation implied PI3K/PKCzeta pathway activation and PKCzeta nuclear translocation as well as nuclear RhoA activation. Thus, the characterization of an endogenous PLD1 that could regulate PC metabolism inside VSMC nucleus provides a new role for this enzyme in control of vascular fibroproliferative disorders.
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Affiliation(s)
- Stéphanie Gayral
- Département Lipoprotéines and Médiateurs Lipidiques, CPTP, INSERM Unité 563, Bâtiment C, CHU Purpan, BP 3028, 31024 Toulouse Cedex 3, France
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8
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Nuwayhid SJ, Vega M, Walden PD, Monaco ME. Regulation of de novo phosphatidylinositol synthesis. J Lipid Res 2006; 47:1449-56. [PMID: 16651661 DOI: 10.1194/jlr.m600077-jlr200] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mechanisms that function to regulate the rate of de novo phosphatidylinositol (PtdIns) synthesis in mammalian cells have not been elucidated. In this study, we characterize the effect of phorbol ester treatment on de novo PtdIns synthesis in C3A human hepatoma cells. Incubation of cells with 12-O-tetradecanoyl phorbol 13-acetate (TPA) initially (1-6 h) results in a decrease in precursor incorporation into PtdIns; however, at later times (18-24 h), a marked increase is observed. TPA-induced glucose uptake from the medium is not required for observation of the stimulation of PtdIns synthesis, because the effect is apparent in glucose-free medium. Inhibition of the activation of arachidonic acid substantially blocks the synthesis of PtdIns but has no effect on the synthesis of phosphatidylcholine (PtdCho). Increasing the concentration of cellular phosphatidic acid by blocking its conversion to diacylglycerol, on the other hand, enhances the synthesis of PtdIns and inhibits the synthesis of PtdCho. The TPA-induced stimulation of PtdIns synthesis is not the result of the concomitant TPA-induced G1 arrest, because G1 arrest induced by mevastatin has no effect on PtdIns synthesis. Inhibition of protein kinase C activity blocks the stimulatory action of TPA on de novo synthesis of PtdIns but has no effect on TPA-induced inhibition. Potential sites of enzymatic regulation are discussed.
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Affiliation(s)
- Samer J Nuwayhid
- Department of Urology, New York University School of Medicine, New York, NY 10016, USA
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9
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Hunt AN. Completing the cycles; the dynamics of endonuclear lipidomics. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:577-87. [PMID: 16581290 DOI: 10.1016/j.bbalip.2006.02.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2006] [Revised: 02/17/2006] [Accepted: 02/20/2006] [Indexed: 12/29/2022]
Abstract
Signal transductions via periodic generation and mobilisation of lipid second messengers within the nuclear matrix of eukaryotic cells have focused renewed attention on their precursor phospholipids' location, structure, form and function. The nuclear matrix contains and supports dynamic pools of phosphatidylcholine and phosphatidylinositol which serve as parent molecules of lipid second messengers but also of other phospholipids requiring cyclical replacement as cells proliferate. Applications of new, highly sensitive and specific analytical methodologies based on tandem electrospray ionisation mass spectrometry and the use of stable isotopes have allowed both static and dynamic lipidomic profiling of these endonuclear phospholipid pools. Together with more conventional enzymatic analyses and evaluation of the effect of specific "knock-out" of phospholipid transfer capacity, a number of important principles have been established. Specifically, a compartmental capacity to synthesise and remodel highly saturated phosphatidylcholine exists alongside transport mechanisms that facilitate the nuclear import of phosphatidylinositol and other phospholipids synthesised elsewhere within the cell. Subnuclear fractionation and the use of newly emerging techniques for sensitive lipidomic profiling of polyphosphoinositides, diacylglycerols and phosphatidate molecular species offer the potential for further significant advances in the near future.
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Affiliation(s)
- Alan N Hunt
- Allergy and Inflammation Research, Division of Infection, Inflammation and Repair, School of Medicine, University of Southampton, Southampton General Hospital, Tremona Road, Southampton SO16 6YD, UK.
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Krupinski J, Slevin M, Badimon L. Citicoline inhibits MAP kinase signalling pathways after focal cerebral ischaemia. Neurochem Res 2006; 30:1067-73. [PMID: 16258856 DOI: 10.1007/s11064-005-7201-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/05/2005] [Indexed: 10/25/2022]
Abstract
The link between membrane phospholipids and different intracellular signal transduction pathways affected by cerebral ischaemia is unclear. CDP-choline, a major neuronal membrane lipid precursor and its intracellular target proteins and transcription factors were studied to further understand its role in ischaemic stroke. Cerebral ischaemia was produced by distal, permanent occlusion of the middle cerebral artery (MCAO) in the rat. Animals receiving 500 mg/kg of CDP-choline in 0.5 ml of 0.9% saline, intraperitoneally, 24 h and 1 h before MCAO and 23 h after MCAO demonstrated a notable reduction in the phosphorylation of MAP-kinase family members, ERK1/2 and MEK1/2, as well as Elk-1 transcription factor, compared with control animals treated with 0.5 ml of 0.9% saline. Immunohistochemistry showed a particular reduction in immunoreactivity in glia. The effects of CDP-choline on intracellular mechanisms of signal transduction, suggests that this molecule may play a key role in recovery after ischaemic stroke.
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Affiliation(s)
- J Krupinski
- Cardiovascular Research Center, IIBB/CSIC-HSCSP-UAB, St.pau hospital, Barcelona, Spain
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11
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Abstract
Once nuclear envelope membranes have been removed from isolated nuclei, around 6% of mammalian cell phospholipid is retained within the nuclear matrix, which calculations suggest may occupy 10% of the volume of this subcellular compartment. It is now acknowledged that endonuclear phospholipid, largely ignored for the past 40 years, provides substrate for lipid-mediated signaling events. However, given its abundance, it likely also has other as yet incompletely defined roles. Endonuclear phosphatidylcholine is the predominant phospholipid comprising distinct and highly saturated molecular species compared with that of the whole cell. Moreover, this unusual composition is subject to tight homeostatic maintenance even under conditions of extreme dietary manipulation, presumably reflecting a functional requirement for highly saturated endonuclear phosphatidylcholine. Recent application of new lipidomic technologies exploiting tandem electrospray ionization mass spectrometry in conjunction with deuterium stable isotope labeling have permitted us to probe not just molecular species compositions but endonuclear phospholipid acquisition and turnover with unparalleled sensitivity and specificity. What emerges is a picture of a dynamic pool of endonuclear phospholipid subject to autonomous regulation with respect to bulk cellular phospholipid metabolism. Compartmental biosynthesis de novo of endonuclear phosphatidylcholine contrasts with import of phosphatidylinositol synthesized elsewhere. However, irrespective of the precise temporal-spatial-dynamic relationships underpinning phospholipid acquisition, derangement of endonuclear lipid-mediated signaling from these parental phospholipids halts cell growth and division indicating a pivotal control point. This in turn defines the manipulation of compartmentalized endonuclear phospholipid acquisition and metabolism as intriguing potential targets for the development of future antiproliferative strategies.
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Affiliation(s)
- Alan N Hunt
- Allergy and Inflammation Research, Division of Infection, Inflammation & Repair, School of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom.
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12
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Farooqui AA, Antony P, Ong WY, Horrocks LA, Freysz L. Retinoic acid-mediated phospholipase A2 signaling in the nucleus. ACTA ACUST UNITED AC 2004; 45:179-95. [PMID: 15210303 DOI: 10.1016/j.brainresrev.2004.03.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/09/2004] [Indexed: 10/26/2022]
Abstract
Retinoic acid modulates a wide variety of biological processes including proliferation, differentiation, and apoptosis. It interacts with specific receptors in the nucleus, the retinoic acid receptors (RARs). The molecular mechanism by which retinoic acid mediates cellular differentiation and growth suppression in neural cells remains unknown. However, retinoic acid-induced release of arachidonic acid and its metabolites may play an important role in cell proliferation, differentiation, and apoptosis. In brain tissue, arachidonic acid is mainly released by the action of phospholipase A2 (PLA2) and phospholipase C (PLC)/diacylglycerol lipase pathways. We have used the model of differentiation in LA-N-1 cells induced by retinoic acid. The treatment of LA-N-1 cells with retinoic acid produces an increase in phospholipase A2 activity in the nuclear fraction. The pan retinoic acid receptor antagonist, BMS493, can prevent this increase in phospholipase A2 activity. This suggests that retinoic acid-induced stimulation of phospholipase A2 activity is a retinoic acid receptor-mediated process. LA-N-1 cell nuclei also have phospholipase C and phospholipase D (PLD) activities that are stimulated by retinoic acid. Selective phospholipase C and phospholipase D inhibitors block the stimulation of phospholipase C and phospholipase D activities. Thus, both direct and indirect mechanisms of arachidonic acid release exist in LA-N-1 cell nuclei. Arachidonic acid and its metabolites markedly affect the neurite outgrowth and neurotransmitter release in cells of neuronal and glial origin. We propose that retinoic acid receptors coupled with phospholipases A2, C and D in the nuclear membrane play an important role in the redistribution of arachidonic acid in neuronal and non-nuclear neuronal membranes during differentiation and growth suppression. Abnormal retinoid metabolism may be involved in the downstream transcriptional regulation of phospholipase A2-mediated signal transduction in schizophrenia and Alzheimer disease (AD). The development of new retinoid analogs with diminished toxicity that can cross the blood-brain barrier without harm and can normalize phospholipase A2-mediated signaling will be important in developing pharmacological interventions for these neurological disorders.
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Affiliation(s)
- Akhlaq A Farooqui
- Department of Molecular and Cellular Biochemistry, The Ohio State University, 1645 Neil Ave, Columbus, OH 43210, USA
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13
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Maté SM, Brenner RR, Ves-Losada A. Phosphatidyl choline fatty acid remodeling in the hepatic cell nuclei. Prostaglandins Leukot Essent Fatty Acids 2004; 70:49-57. [PMID: 14643179 DOI: 10.1016/j.plefa.2003.08.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
This study was performed to determine whether fatty acids incorporated into liver cell nuclei phosphatidylcholine (PtdCho) could be remodeled in the isolated nuclear. For this reason, rat liver cell nuclei were incubated in vitro with [1-14C]20:4n-6-CoA. PtdCho molecular species with the highest specific activity had an unsaturated fatty acid at sn-1 and sn-2 positions (20:4-20:4>18:2-20:4>18:1-20:4). 16:0-20:4 and 18:0-20:4 PtdChos showed a minor specific activity. When labeled nuclei were reincubated in the absence of labeled substrate with the addition of cytosol, ATP and CoA, the specific activity of 20:4-20:4, 18:2-20:4 and 18:1-20:4 species decreased, while that of 16:0-20:4 and 18:0-20:4 increased. In conclusion, the asymmetric fatty acid distribution of saturated fatty acids at sn-1 position, and unsaturated fatty acids at sn-2 position of nuclear PtdCho molecular species was re-established by an acyl-CoA-dependent remodeling process.
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Affiliation(s)
- S M Maté
- Facultad de Ciencias Médicas, Instituto de Investigaciones Bioquímicas de La Plata, UNLP-CONICET, calles 60 y 120, 1900 La Plata, Argentina
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14
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Abstract
Lipids have long been recognized as quantitatively minor components of the nucleus, where they were initially thought to have little functional importance; but they now command growing interest, with recognition of their diverse signaling and modulating properties in that organelle. This applies to the lipid-poor compartments of the nucleoplasm as well as the relatively lipid-rich nuclear envelope. Phosphoglycerides and sphingomyelin, as the predominant lipids, have attracted the most interest among researchers, but some of the less-abundant lipids such as gangliosides, sphingosine, and sphingosine phosphate are now becoming recognized as functionally important nuclear constituents. Among recent advances in this emerging field are detailed findings on the metabolic enzymes that synthesize and catabolize nuclear lipids; the fact that these are localized primarily within the nucleus itself indicates considerable autonomy with respect to lipid metabolism. Current studies suggest several key processes involving RNA and DNA reactivity that are dependent on these lipid-initiated events. Neural cell nuclei have been the subject of such investigations, with results that closely parallel the more numerous studies on nuclei of extraneural cells. This review attempts to outline some of the major findings on nuclear lipids of diverse cell types; results with nonneural nuclei will hopefully provide useful guideposts to further studies of neural systems.
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Affiliation(s)
- Robert W Ledeen
- Department of Neurology and Neurosciences, New Jersey Medical School, The University of Medicine and Dentistry of New Jersey, 185 South Orange Avenue, Newark, NJ 07103, USA.
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15
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Antony P, Petro JB, Carlesso G, Shinners NP, Lowe J, Khan WN. B Cell receptor directs the activation of NFAT and NF-κB via distinct molecular mechanisms. Exp Cell Res 2003; 291:11-24. [PMID: 14597404 DOI: 10.1016/s0014-4827(03)00338-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BCR engagement initiates intracellular calcium ([Ca2+]i) mobilization which is critical for the activation of multiple transcription factors including NF-kappaB and NFAT. Previously, we showed that Bruton's tyrosine kinase (BTK)-deficient (btk-/-) B cells, which display a modestly reduced calcium response to BCR crosslinking, do not activate NF-kappaB. Here we show that BTK is also essential for the activation of NFAT following BCR engagement. Pharmacological mobilization of [Ca2+]i in BTK-deficient DT40 B cells (DT40.BTK) does not rescue BCR directed activation of NF-kappaB and only partially that of NFAT, suggesting existence of additional BTK-signaling pathways in this process. Therefore, we investigated a requirement for BTK in the production of diacylglycerol (DAG). We found that DT40.BTK B cells do not produce DAG in response to BCR engagement. Pharmacological inhibition of PKC isozymes and Ras revealed that the BCR-induced activation of NF-kappaB requires conventional PKCbeta, whereas that of NFAT may involve non-conventional PKCdelta and Ras pathways. Consistent with an essential role for BTK in the regulation of NFAT, B cells from btk-/- mice display defective expression of CD5, a gene under the control of NFAT. Together, these results suggest that BCR employs distinct BTK-dependent molecular mechanisms to regulate the activation of NF-kappaB versus NFAT.
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Affiliation(s)
- Pierre Antony
- Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA
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Antony P, Kanfer JN, Freysz L. Retinoic acid specifically activates an oleate-dependent phospholipase D in the nuclei of LA-N-1 neuroblastoma cells. FEBS Lett 2003; 541:93-6. [PMID: 12706826 DOI: 10.1016/s0014-5793(03)00313-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Earlier studies showed that treatment of LA-N-1 cells with TPA, a tumoral promoter, leads to the stimulation of a G protein-regulated phospholipase D (PLD) in the nuclei. Now we demonstrate that retinoic acid, a cellular differentiation inducing agent, activates a nuclear oleate-dependent PLD in LA-N-1 cells. Treatment of the nuclei with retinoic acid induces the breakdown of phosphatidylcholine (PtdCho). Our results indicate that PLD is regulated differentially depending on the nature of the stimulatory agent. These results strongly suggest the existence of two nuclear PLD isoforms in LA-N-1 nuclei that hydrolyze PtdCho.
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Affiliation(s)
- Pierre Antony
- Institut de Chimie Biologique, Faculte de Medecine, Laboratoire de Neurobiologie Moleculaire des Interactions Cellulaires, Strasbourg, France.
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Jones DR, D'Santos CS, Mérida I, Divecha N. T lymphocyte nuclear diacylglycerol is derived from both de novo synthesis and phosphoinositide hydrolysis. Int J Biochem Cell Biol 2002; 34:158-68. [PMID: 11809418 DOI: 10.1016/s1357-2725(01)00108-x] [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: 10/27/2022]
Abstract
Novel phospholipid metabolism in T lymphocytes and the generation of biologically active lipid second messengers (LSMs) has attracted much attention in recent years. Despite this interest, no reports have attempted to characterise such events in the nuclei of these cells. In order to gain insight into the structural relationships between the lipids diglyceride (DG) and phosphatidic acid (PtdOH) and their structural precursors phosphatidylcholine (PtdCho) and phosphatidylinositides (PtdIns) in the nuclei of CTLL-2 T lymphocytes, an analysis of their molecular species was performed. The results clearly indicated that there were two pools of DG. The major pool consisted primarily of saturated and monunsaturated structures whereas the minor pool consisted of more unsaturated species, most likely derived from PtdIns. Only the latter pool was found to be accessible to endogenous nuclear diacylglycerol kinase (DGK) activity which showed partial inhibition with the recognised DGK inhibitor R59949. Molecular species analysis of the endogenous nuclear PtdOH revealed it to be distinct from that generated by the endogenous DGK, but instead resembled that of PtdCho species. We were unable to detect enzymatic activities which targeted PtdCho (PtdCho-phospholipase C (PtdCho-PLC), PtdCho-phospholipase D (PtdCho-PLD) and sphingomyelin synthase (SMS)) but instead a detectable PtdOH phosphatase (PAP) activity. We propose that, in exponentially growing CTLL-2 cells, synthesis de novo represents one of the routes for the biosynthesis of structural phospholipids which may be the source of biologically active LSMs in the nucleus.
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Affiliation(s)
- David R Jones
- Department of Immunology and Oncology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Cantoblanco, 28049 Madrid, Spain.
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Antony P, Farooqui AA, Horrocks LA, Freysz L. Effect of D609 on phosphatidylcholine metabolism in the nuclei of LA-N-1 neuroblastoma cells: a key role for diacylglycerol. FEBS Lett 2001; 509:115-8. [PMID: 11734217 DOI: 10.1016/s0014-5793(01)03149-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In our previous studies, TPA treatment of LA-N-1 cells stimulated the production of diacylglycerol in nuclei, probably through the activation of a phospholipase C. Stimulation of the synthesis of nuclear phosphatidylcholine by the activation of CTP:phosphocholine cytidylyltransferase was also observed. The present data show that both effects were inhibited by the pretreatment of the cells with D609, a selective phosphatidylcholine-phospholipase C inhibitor, indicating that the diacylglycerol produced through the hydrolysis of phosphatidylcholine in the nuclei is reutilized for the synthesis of nuclear phosphatidylcholine and is required for the activation of CTP:phosphocholine cytidylyltransferase.
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Affiliation(s)
- P Antony
- Laboratoire de Neurobiologie Moléculaire des Interactions Cellulaires, Institut de Chimie Biologique, Faculté de Médecine, Strasbourg, France
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Antony P, Freysz L, Horrocks LA, Farooqui AA. Effect of retinoic acid on the Ca2+-independent phospholipase A2 in nuclei of LA-N-1 neuroblastoma cells. Neurochem Res 2001; 26:83-8. [PMID: 11358286 DOI: 10.1023/a:1007636801035] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
LA-N-1 neuroblastoma cell cultures contain Ca2+-independent phospholipases A2 hydrolyzing phosphatidylethanolamine and ethanolamine plasmalogens. These enzymes differ from each other in their molecular mass, substrate specificity, and kinetic properties. Subcellular distribution studies have indicated that the activity of these phospholipases is not only localized in the cytosol but also in non-nuclear membranes and in nuclei. The treatment of LA-N-1 neuroblastoma cell cultures with retinoic acid results in a marked stimulation of Ca2+-independent phospholipases A2 hydrolyzing phosphatidylethanolamine and plasmenylethanolamine. The increase of the activities of both enzymes was first observed in nuclei followed by those present in the cytosol. No effect of retinoic acid on either phospholipase activity could be observed in non-nuclear membranes. The stimulation of these enzymes may be involved in the generation and regulation of arachidonic acid and its metabolites during differentiation.
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Affiliation(s)
- P Antony
- Laboratoire de Neurobiologie Moléculaire des Interactions Cellulaires, Institut de Chimie Biologique, Faculté de Médecine, Strasbourg, France
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