101
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Suhaiman L, De Blas GA, Obeid LM, Darszon A, Mayorga LS, Belmonte SA. Sphingosine 1-phosphate and sphingosine kinase are involved in a novel signaling pathway leading to acrosomal exocytosis. J Biol Chem 2010; 285:16302-14. [PMID: 20236935 DOI: 10.1074/jbc.m109.072439] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Regulated secretion is a central issue for the specific function of many cells; for instance, mammalian sperm acrosomal exocytosis is essential for egg fertilization. Sphingosine 1-phosphate is a bioactive sphingolipid that regulates crucial physiological processes. Here we report that this lipid triggers acrosomal exocytosis in human sperm by a mechanism involving a G(i)-coupled receptor. Real-time imaging showed a remarkable increase of cytosolic calcium upon activation with sphingosine 1-phosphate and pharmacological experiments indicate that the process requires extracellular calcium influx through voltage and store-operated calcium channels and efflux from intracellular stores through inositol 1,4,5-trisphosphate-sensitive calcium channels. Sphingosine 1-phosphate-induced exocytosis requires phospholipase C and protein kinase C activation. We investigated possible sources of the lipid. Western blot indicates that sphingosine kinase 1 is present in spermatozoa. Indirect immunofluorescence showed that phorbol ester, a potent protein kinase C activator that can also trigger acrosomal exocytosis, redistributes sphingosine kinase 1 to the acrosomal region. Functional assays showed that phorbol ester-induced exocytosis depends on the activation of sphingosine kinase 1. Furthermore, incorporation of (32)P to sphingosine demonstrates that cells treated with the phorbol ester increase their sphingosine kinase activity that yields sphingosine 1-phosphate. We present here the first evidence indicating that human spermatozoa produce sphingosine 1-phosphate when challenged with an exocytic stimulus. These observations point to a new role of sphingosine 1-phosphate in a signaling cascade that facilitates acrosome reaction providing some clues about novel lipid molecules involved in exocytosis.
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Affiliation(s)
- Laila Suhaiman
- Laboratorio de Biología Celular y Molecular, Instituto de Histología y Embriología, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencias Médicas, CC56, Universidad Nacional de Cuyo, Mendoza 5500, Argentina
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102
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Lee DH, Jeon BT, Jeong EA, Kim JS, Cho YW, Kim HJ, Kang SS, Cho GJ, Choi WS, Roh GS. Altered expression of sphingosine kinase 1 and sphingosine-1-phosphate receptor 1 in mouse hippocampus after kainic acid treatment. Biochem Biophys Res Commun 2010; 393:476-80. [PMID: 20152803 DOI: 10.1016/j.bbrc.2010.02.027] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Accepted: 02/06/2010] [Indexed: 11/19/2022]
Abstract
Kainic acid (KA) induces hippocampal cell death and astrocyte proliferation. There are reports that sphingosine kinase (SPHK)1 and sphingosine-1- phosphate (S1P) receptor 1 (S1P(1)) signaling axis controls astrocyte proliferation. Here we examined the temporal changes of SPHK1/S1P(1) in mouse hippocampus during KA-induced hippocampal cell death. Mice were killed at 2, 6, 24, or 48 h after KA (30 mg/kg) injection. There was an increase in Fluoro-Jade B-positive cells in the hippocampus of KA-treated mice with temporal changes of glial fibrillary acidic protein (GFAP) expression. The lowest level of SPHK1 protein expression was found 2h after KA treatment. Six hours after KA treatment, the expression of SPHK1 and S1P(1) proteins steadily increased in the hippocampus. In immunohistochemical analysis, SPHK1 and S1P(1) are more immunoreactive in astrocytes within the hippocampus of KA-treated mice than in hippocampus of control mice. These results indicate that SPHK1/S1P(1) signaling axis may play an important role in astrocytes proliferation during KA-induced excitotoxicity.
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Affiliation(s)
- Dong Hoon Lee
- Department of Anatomy and Neurobiology, Institute of Health Sciences, Medical Research Center for Neural Dysfunction, Biomedical Center (BK21), Gyeongsang National University School of Medicine, Jinju, Gyeongnam 660-751, Republic of Korea
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103
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Gratschev D, Löf C, Heikkilä J, Björkbom A, Sukumaran P, Hinkkanen A, Slotte JP, Törnquist K. Sphingosine kinase as a regulator of calcium entry through autocrine sphingosine 1-phosphate signaling in thyroid FRTL-5 cells. Endocrinology 2009; 150:5125-34. [PMID: 19797403 DOI: 10.1210/en.2009-0288] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Calcium entry is one of the main regulators of intracellular signaling. Here, we have described the importance of sphingosine, sphingosine kinase 1 (SK1), and sphingosine 1-phosphate (S1P) in regulating calcium entry in thyroid FRTL-5 cells. In cells incubated with the phosphatase inhibitor calyculin A, which evokes calcium entry without mobilizing sequestered intracellular calcium, sphingosine inhibited calcium entry in a concentration-dependent manner. Furthermore, inhibiting SK1 or the ATP-binding cassette ABCC1 multidrug transporter attenuated calcium entry. The addition of exogenous S1P restored calcium entry. Neither sphingosine nor inhibition of SK1 attenuated thapsigargin-evoked calcium entry. Blocking S1P receptor 2 or phospholipase C attenuated calcium entry, whereas blocking S1P receptor 3 did not. Overexpression of wild-type SK1, but not SK2, enhanced calyculin-evoked calcium entry compared with mock-transfected cells, whereas calcium entry was decreased in cells transfected with the dominant-negative G82D SK1 mutant. Exogenous S1P restored calcium entry in G82D cells. Our results suggest that the calcium entry pathway is blocked by sphingosine and that activation of SK1 and the production of S1P, through an autocrine mechanism, facilitate calcium entry through activation of S1P receptor 2. This is a novel mechanism by which the sphingosine-S1P rheostat regulates cellular calcium homeostasis.
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Affiliation(s)
- Dan Gratschev
- Department of Biology, Abo Akademi University, BioCity, Tykistökatu 6, 20520 Turku, Finland
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104
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Crousillac S, Colonna J, McMains E, Dewey JS, Gleason E. Sphingosine-1-phosphate elicits receptor-dependent calcium signaling in retinal amacrine cells. J Neurophysiol 2009; 102:3295-309. [PMID: 19776367 DOI: 10.1152/jn.00119.2009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Evidence is emerging indicating that sphingosine-1-phosphate (S1P) participates in signaling in the retina. To determine whether S1P might be involved in signaling in the inner retina specifically, we examine the effects of this sphingolipid on cultured retinal amacrine cells. Whole cell voltage-clamp recordings reveal that S1P activates a cation current that is dependent on signaling through G(i) and phospholipase C. These observations are consistent with the involvement of members of the S1P receptor family of G-protein-coupled receptors in the production of the current. Immunocytochemistry and PCR amplification provide evidence for the expression of S1P1R and S1P3R in amacrine cells. The receptor-mediated channel activity is shown to be highly sensitive to blockade by lanthanides consistent with the behavior of transient receptor potential canonical (TRPC) channels. PCR products amplified from amacrine cells reveal that TRPCs 1 and 3-7 channel subunits have the potential to be expressed. Because TRPC channels provide a Ca(2+) entry pathway, we asked whether S1P caused cytosolic Ca(2+) elevations in amacrine cells. We show that S1P-dependent Ca(2+) elevations do occur in these cells and that they might be mediated by S1P1R and S1P3R. The Ca(2+) elevations are partially due to release from internal stores, but the largest contribution is from influx across the plasma membrane. The effect of inhibition of sphingosine kinase suggests that the production of cytosolic S1P underlies the sustained nature of the Ca(2+) elevations. Elucidation of the downstream effects of these signals will provide clues to the role of S1P in regulating inner retinal function.
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Affiliation(s)
- Scott Crousillac
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
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105
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Darios F, Wasser C, Shakirzyanova A, Giniatullin A, Goodman K, Munoz-Bravo JL, Raingo J, Jorgačevski J, Kreft M, Zorec R, Rosa JM, Gandia L, Gutiérrez LM, Binz T, Giniatullin R, Kavalali ET, Davletov B. Sphingosine facilitates SNARE complex assembly and activates synaptic vesicle exocytosis. Neuron 2009; 62:683-94. [PMID: 19524527 PMCID: PMC2697323 DOI: 10.1016/j.neuron.2009.04.024] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Revised: 11/27/2008] [Accepted: 04/21/2009] [Indexed: 11/20/2022]
Abstract
Synaptic vesicles loaded with neurotransmitters fuse with the plasma membrane to release their content into the extracellular space, thereby allowing neuronal communication. The membrane fusion process is mediated by a conserved set of SNARE proteins: vesicular synaptobrevin and plasma membrane syntaxin and SNAP-25. Recent data suggest that the fusion process may be subject to regulation by local lipid metabolism. Here, we have performed a screen of lipid compounds to identify positive regulators of vesicular synaptobrevin. We show that sphingosine, a releasable backbone of sphingolipids, activates synaptobrevin in synaptic vesicles to form the SNARE complex implicated in membrane fusion. Consistent with the role of synaptobrevin in vesicle fusion, sphingosine upregulated exocytosis in isolated nerve terminals, neuromuscular junctions, neuroendocrine cells and hippocampal neurons, but not in neurons obtained from synaptobrevin-2 knockout mice. Further mechanistic insights suggest that sphingosine acts on the synaptobrevin/phospholipid interface, defining a novel function for this important lipid regulator.
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Affiliation(s)
| | - Catherine Wasser
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | | | | | - Kerry Goodman
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | | | - Jesica Raingo
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jernej Jorgačevski
- Laboratory of Neuroendocrinology and Molecular Cell Physiology, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Marko Kreft
- Laboratory of Neuroendocrinology and Molecular Cell Physiology, University of Ljubljana, 1000 Ljubljana, Slovenia
- Celica Biomedical Center, 1000 Ljubljana, Slovenia
| | - Robert Zorec
- Laboratory of Neuroendocrinology and Molecular Cell Physiology, University of Ljubljana, 1000 Ljubljana, Slovenia
- Celica Biomedical Center, 1000 Ljubljana, Slovenia
| | - Juliana M. Rosa
- Teófilo Hernando Institute and Department of pharmacology and therapeutics, Autonomous University of Madrid, 28049 Madrid, Spain
| | - Luis Gandia
- Teófilo Hernando Institute and Department of pharmacology and therapeutics, Autonomous University of Madrid, 28049 Madrid, Spain
| | - Luis M. Gutiérrez
- Institute of Neurosciences, CSIC-Miguel Hernández University, 03550 Alicante, Spain
| | - Thomas Binz
- Department of Biochemistry, Medizinische Hochschule Hannover, 30625 Hanover, Germany
| | - Rashid Giniatullin
- Virtanen Institute for Molecular Sciences, University of Kuopio, 70600 Kuopio, Finland
| | - Ege T. Kavalali
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX 75390, USA
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106
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Sim-Selley LJ, Goforth PB, Mba MU, Macdonald TL, Lynch KR, Milstien S, Spiegel S, Satin LS, Welch SP, Selley DE. Sphingosine-1-phosphate receptors mediate neuromodulatory functions in the CNS. J Neurochem 2009; 110:1191-202. [PMID: 19493165 DOI: 10.1111/j.1471-4159.2009.06202.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Sphingosine-1-phosphate (S1P) is a ubiquitous, lipophilic cellular mediator that acts in part by activation of G-protein-coupled receptor. Modulation of S1P signaling is an emerging pharmacotherapeutic target for immunomodulatory drugs. Although multiple S1P receptor types exist in the CNS, little is known about their function. Here, we report that S1P stimulated G-protein activity in the CNS, and results from [(35)S]GTPgammaS autoradiography using the S1P(1)-selective agonist SEW2871 and the S1P(1/3)-selective antagonist VPC44116 show that in several regions a majority of this activity is mediated by S1P(1) receptors. S1P receptor activation inhibited glutamatergic neurotransmission as determined by electrophysiological recordings in cortical neurons in vitro, and this effect was mimicked by SEW2871 and inhibited by VPC44116. Moreover, central administration of S1P produced in vivo effects resembling the actions of cannabinoids, including thermal antinociception, hypothermia, catalepsy and hypolocomotion, but these actions were independent of CB(1) receptors. At least one of the central effects of S1P, thermal antinociception, is also at least partly S1P(1) receptor mediated because it was produced by SEW2871 and attenuated by VPC44116. These results indicate that CNS S1P receptors are part of a physiologically relevant and widespread neuromodulatory system, and that the S1P(1) receptor contributes to S1P-mediated antinociception.
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Affiliation(s)
- Laura J Sim-Selley
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, USA.
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107
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Yu H, Okada T, Kobayashi M, Abo-Elmatty DM, Jahangeer S, Nakamura SI. Roles of extracellular and intracellular sphingosine 1-phosphate in cell migration. Genes Cells 2009; 14:597-605. [PMID: 19371379 DOI: 10.1111/j.1365-2443.2009.01295.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Sphingosine 1-phosphate (S1P) is an important factor for the regulation of cell motility acting both inside and outside the cells. The precise role of S1P in the control of cell motility, however, remains unclear. Here we describe the roles of S1P in the regulation of cell motility by dissecting them into intracellular and extracellular actions using a liposomal S1P transfer technique. In a Boyden chamber assay free S1P enhanced directional cell movement, whereas liposomal S1P induced nondirectional cell movement. Furthermore, inhibition of sphingosine kinase (SphK) 1 by several inhibitors or knockdown of the enzyme expression by siRNA caused reduced wound-faced cell polarity formation as assessed by wound-healing assay. Moreover, S1P-induced cell migration was strongly inhibited by SphK inhibitors. These results indicate that extracellular S1P acting through S1P receptors facilitates the formation of cell polarity, whereas S1P generated inside the cells functions as an intracellular mediator per se to enhance nondirectional cell movement, thus S1P enhances directional cell movement in a coordinated fashion.
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Affiliation(s)
- Huan Yu
- Division of Biochemistry, Department of Molecular and Cellular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
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108
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Coste O, Brenneis C, Linke B, Pierre S, Maeurer C, Becker W, Schmidt H, Gao W, Geisslinger G, Scholich K. Sphingosine 1-phosphate modulates spinal nociceptive processing. J Biol Chem 2008; 283:32442-51. [PMID: 18805787 DOI: 10.1074/jbc.m806410200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Sphingosine 1-Phosphate (S1P) modulates various cellular functions such as apoptosis, cell differentiation, and migration. Although S1P is an abundant signaling molecule in the central nervous system, very little is known about its influence on neuronal functions. We found that S1P concentrations were selectively decreased in the cerebrospinal fluid of adult rats in an acute and an inflammatory pain model. Pharmacological inhibition of sphingosine kinases (SPHK) decreased basal pain thresholds and SphK2 knock-out mice, but not SphK1 knock-out mice, had a significant decrease in withdrawal latency. Intrathecal application of S1P or sphinganine 1-phosphate (dihydro-S1P) reduced the pain-related (nociceptive) behavior in the formalin assay. S1P and dihydro-S1P inhibited cyclic AMP (cAMP) synthesis, a key second messenger of spinal nociceptive processing, in spinal cord neurons. By combining fluorescence resonance energy transfer (FRET)-based cAMP measurements with Multi Epitope Ligand Cartography (MELC), we showed that S1P decreased cAMP synthesis in excitatory dorsal horn neurons. Accordingly, intrathecal application of dihydro-S1P abolished the cAMP-dependent phosphorylation of NMDA receptors in the outer laminae of the spinal cord. Taken together, the data show that S1P modulates spinal nociceptive processing through inhibition of neuronal cAMP synthesis.
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Affiliation(s)
- Ovidiu Coste
- Pharmazentrum Frankfurt, ZAFES, Institute for Clinical Pharmacology, Klinikum der Johann Wolfgang Goethe-Universität Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
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109
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Coste O, Pierre S, Marian C, Brenneis C, Angioni C, Schmidt H, Popp L, Geisslinger G, Scholich K. Antinociceptive activity of the S1P-receptor agonist FTY720. J Cell Mol Med 2008; 12:995-1004. [PMID: 18494940 PMCID: PMC4401143 DOI: 10.1111/j.1582-4934.2008.00160.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
FTY720 is a novel immunosuppressive drug that inhibits the egress of lymphocytes from secondary lymphoid tissues and thymus. In its phosphorylated form FTY720 is a potent S1P receptor agonist. Recently it was also shown that FTY720 can reduce prostaglandin synthesis through the direct inhibition of the cytosolic phospholipase A2 (cPLA2). Since prostaglandins are important mediators of nociception, we studied the effects of FTY720 in different models of nociception. We found that intraperitoneal administration of FTY720 reduced dose-dependently the nociceptive behaviour of rats in the formalin assay. Although the antinociceptive doses of FTY720 were too low to alter the lymphocyte count, prostanoid concentrations in the plasma were dramatically reduced. Surprisingly, intrathecally administered FTY720 reduced the nociceptive behaviour in the formalin assay without altering spinal prostaglandin synthesis, indicating that additional antinociceptive mechanisms beside the inhibition of prostaglandin synthesis are involved. Accordingly, FTY720 reduced also the nociceptive behaviour in the spared nerve injury model for neuropathic pain which does not depend on prostaglandin synthesis. In this model the antinociceptive effect of FTY720 was similar to gabapentin, a commonly used drug to treat neuropathic pain. Taken together we show for the first time that FTY720 possesses antinociceptive properties and that FTY720 reduces nociceptive behaviour during neuropathic pain.
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Affiliation(s)
- Ovidiu Coste
- Pharmazentrum Frankfurt, ZAFES, Klinikum der Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, Germany
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110
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Miron VE, Schubart A, Antel JP. Central nervous system-directed effects of FTY720 (fingolimod). J Neurol Sci 2008; 274:13-7. [PMID: 18678377 DOI: 10.1016/j.jns.2008.06.031] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2008] [Accepted: 06/27/2008] [Indexed: 11/30/2022]
Abstract
FTY720, also known as fingolimod, is an orally administered sphingosine-1-phosphate (S1P) analogue that is under investigation as a therapy for both relapsing-remitting (RR) and progressive forms of multiple sclerosis (MS). The demonstrated beneficial effect of FTY720 on disease activity in RR-MS patients and in the animal model experimental autoimmune encephalomyelitis (EAE) is largely attributed to effects on the systemic immune system. In addition, unlike other current systemic immuno-modulators used in MS, the lipophilic nature of FTY720 allows it to cross the blood-brain barrier (BBB). Since S1P receptors are expressed on all cell types, FTY720 has the potential to exert effects directly on the BBB and on resident cells of the CNS. The latter include cells implicated in regulating immune reactivity within the CNS (astrocytes, microglia), those that are targeted by the disease process (oligodendrocytes, neurons), and those involved in repair (oligodendrocyte progenitor cells). In vitro studies document the dose-dependent effects of FTY720 on neural cell survival, differentiation, and cytoskeletal dynamics. Animal model studies, specifically EAE, indicate an overall neuroprotective effect of FTY720 mediated at least in part by its actions within the CNS. Ongoing studies will need to define the direct and indirect (via immune-modulation) effects of FTY720 on the CNS across the broad clinical spectrum of MS.
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Affiliation(s)
- Veronique E Miron
- Neuroimmunology Unit, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada H3A 2B4.
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111
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Okada T, Kajimoto T, Jahangeer S, Nakamura SI. Sphingosine kinase/sphingosine 1-phosphate signalling in central nervous system. Cell Signal 2008; 21:7-13. [PMID: 18694820 DOI: 10.1016/j.cellsig.2008.07.011] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 07/04/2008] [Accepted: 07/17/2008] [Indexed: 11/30/2022]
Abstract
Sphingolipids were once regarded as inert structural components of cell membranes. Now these metabolites are generally believed to be important bioactive molecules that control a wide repertoire of cellular processes such as proliferation and survival of cells. Along with these ubiquitous cell functions observed in many peripheral tissues sphingolipid metabolites, especially sphingosine 1-phosphate, exert important neuron-specific functions such as regulation of neurotransmitter release. This review summarizes physiological and pathological roles of sphingolipid metabolites emphasizing the role of sphingosine 1-phosphate in the central nervous system.
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Affiliation(s)
- Taro Okada
- Division of Biochemistry, Department of Biochemistry/Molecular Biology, Kobe University Graduate School of Medicine, Kobe, 650-0017, Japan
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112
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Bryan L, Kordula T, Spiegel S, Milstien S. Regulation and functions of sphingosine kinases in the brain. Biochim Biophys Acta Mol Cell Biol Lipids 2008; 1781:459-66. [PMID: 18485923 DOI: 10.1016/j.bbalip.2008.04.008] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Revised: 04/14/2008] [Accepted: 04/19/2008] [Indexed: 01/13/2023]
Abstract
It has long been known that sphingolipids, especially sphingomyelin, a principal component of myelin, are highly enriched in the central nervous system and are structural components of all eukaryotic cell membranes. In the last few years, substantial evidence has accumulated from studies of many types of cells demonstrating that in addition to their structural roles, their breakdown products form a new class of signaling molecules with potent and myriad regulatory effects on essentially every cell in the body. While the sphingolipid metabolites sphingosine and its precursor ceramide have been associated with cell growth arrest and apoptosis, sphingosine-1-phosphate (S1P) enhances proliferation, differentiation, and cell survival as well as regulates many physiological and pathological processes. The relative levels of these three interconvertible sphingolipid metabolites, and thus cell fate, are strongly influenced by the activity of sphingosine kinases, of which there are two isoforms, designated SphK1 and SphK2, the enzymes that phosphorylate sphingosine to produce S1P. Not much is yet known of the importance of S1P in the central nervous system. Therefore, this review is focused on current knowledge of regulation of SphK1 and SphK2 on both transcriptional and post-translational levels and the functions of these isozymes and their product S1P and its receptors in the central nervous system.
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Affiliation(s)
- Lauren Bryan
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA
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113
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Wu YP, Mizugishi K, Bektas M, Sandhoff R, Proia RL. Sphingosine kinase 1/S1P receptor signaling axis controls glial proliferation in mice with Sandhoff disease. Hum Mol Genet 2008; 17:2257-64. [PMID: 18424450 DOI: 10.1093/hmg/ddn126] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Sphingosine-1-phosphate (S1P) is a lipid-signaling molecule produced by sphingosine kinase in response to a wide number of stimuli. By acting through a family of widely expressed G protein-coupled receptors, S1P regulates diverse physiological processes. Here we examined the role of S1P signaling in neurodegeneration using a mouse model of Sandhoff disease, a prototypical neuronopathic lysosomal storage disorder. When sphingosine kinase 1 (Sphk1) was deleted in Sandhoff disease mice, a milder disease course occurred, with decreased proliferation of glial cells and less-pronounced astrogliosis. A similar result of milder disease course and reduced astroglial proliferation was obtained by deletion of the gene for the S1P(3) receptor, a G protein-coupled receptor enriched in astrocytes. Our studies demonstrate a functional role of S1P synthesis and receptor expression in astrocyte proliferation leading to astrogliosis during the terminal stages of neurodegeneration in Sandhoff disease mice. Because astrocyte responses are involved in many types of neurodegeneration, the Sphk1/S1P receptor signaling axis may be generally important during the pathogenesis of neurodegenerative diseases.
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Affiliation(s)
- Yun-Ping Wu
- Genetics of Development and Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-1821, USA
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114
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Dev KK, Mullershausen F, Mattes H, Kuhn RR, Bilbe G, Hoyer D, Mir A. Brain sphingosine-1-phosphate receptors: implication for FTY720 in the treatment of multiple sclerosis. Pharmacol Ther 2007; 117:77-93. [PMID: 17961662 DOI: 10.1016/j.pharmthera.2007.08.005] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2007] [Accepted: 08/16/2007] [Indexed: 10/22/2022]
Abstract
Multiple sclerosis (MS) is an autoimmune, neurological disability with unknown etiology. The current therapies available for MS work by an immunomodulatory action, preventing T-cell- and macrophage-mediated destruction of brain-resident oligodendrocytes and axonal loss. Recently, FTY720 (fingolimod) was shown to significantly reduce relapse rates in MS patients and is currently in Phase III clinical trials. This drug attenuates trafficking of harmful T cells entering the brain by regulating sphingosine-1-phosphate (S1P) receptors. Here, we outline the direct roles that S1P receptors play in the central nervous system (CNS) and discuss additional modalities by which FTY720 may provide direct neuroprotection in MS.
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Affiliation(s)
- Kumlesh K Dev
- Department of Anatomy and Neuroscience, University College Cork, Windle Building, Cork, Ireland.
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