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Javed A, Soliven B. Fingolimod: a novel oral immunomodulatory treatment for multiple sclerosis. FUTURE NEUROLOGY 2011. [DOI: 10.2217/fnl.11.15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fingolimod (FTY720), an immunomodulator that acts on sphingosine-1-phosphate receptors, is the first oral disease-modifying agent to be approved by the US FDA for the treatment of relapsing forms of multiple sclerosis (MS). Compared with other disease-modifying agents, fingolimod is unique in its mechanisms of action: it sequesters lymphocytes into lymph nodes without directly inhibiting effector functions, and it exerts pleiotropic actions on cultured oligodendrocytes and oligodendrocyte progenitors. Whether the latter contributes to the favorable response to this drug is currently being investigated. Results from Phase II and III clinical trials demonstrate that fingolimod is highly effective in relapsing–remitting MS. In this article, we review the background on MS therapy, the mechanisms and pharmacology of fingolimod and its benefit–risk profile as a novel therapy in MS.
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Affiliation(s)
- Adil Javed
- Department of Neurology MC2030, The University of Chicago, 5841 South Maryland Avenue, Chicago, IL 60637, USA
| | - Betty Soliven
- Department of Neurology MC2030, The University of Chicago, 5841 South Maryland Avenue, Chicago, IL 60637, USA
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Kim HJ, Miron VE, Dukala D, Proia RL, Ludwin SK, Traka M, Antel JP, Soliven B. Neurobiological effects of sphingosine 1‐phosphate receptor modulation in the cuprizone model. FASEB J 2011; 25:1509-18. [DOI: 10.1096/fj.10-173203] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Hye Jung Kim
- Department of NeurologyUniversity of ChicagoChicagoIllinoisUSA
| | | | - Danuta Dukala
- Department of NeurologyUniversity of ChicagoChicagoIllinoisUSA
| | - Richard L. Proia
- Genetics of Development and Disease BranchNational Institutes of HealthMarylandUSA
| | - Samuel K. Ludwin
- Department of NeuropathologyQueen's UniversityKingstonOntarioCanada
| | - Maria Traka
- Department of NeurologyUniversity of ChicagoChicagoIllinoisUSA
| | - Jack P. Antel
- Department of NeuroimmunologyMcGill UniversityMontrealQuebecCanada
| | - Betty Soliven
- Department of NeurologyUniversity of ChicagoChicagoIllinoisUSA
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Frugier T, Crombie D, Conquest A, Tjhong F, Taylor C, Kulkarni T, McLean C, Pébay A. Modulation of LPA Receptor Expression in the Human Brain Following Neurotrauma. Cell Mol Neurobiol 2011; 31:569-77. [DOI: 10.1007/s10571-011-9650-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Accepted: 01/05/2011] [Indexed: 01/07/2023]
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Portaccio E. Evidence-based assessment of potential use of fingolimod in treatment of relapsing multiple sclerosis. CORE EVIDENCE 2011; 6:13-21. [PMID: 21468239 PMCID: PMC3065557 DOI: 10.2147/ce.s10101] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Indexed: 11/23/2022]
Abstract
Multiple sclerosis is an autoimmune inflammatory demyelinating disease of the central nervous system and represents one of the most common causes of chronic neurologic disability in young adults. All the current disease-modifying drugs are administered parenterally, and can be associated with varying degrees of injection site or infusion-related reactions. Together with other side effects, the parenteral route of administration is one of the key factors affecting adherence to therapy in multiple sclerosis. Fingolimod (FTY720) is an immunomodulator that acts on sphingosine 1-phosphate (S1P) receptors and is the first oral drug approved by the US Food and Drug Administration for the treatment of relapsing-remitting multiple sclerosis. Downmodulation of S1P receptor type 1 (S1P1) slows the egress of lymphocytes from lymph nodes and recirculation to the central nervous system, reduces astrogliosis, and inhibits angiogenesis during chronic neuroinflammation. Fingolimod also regulates the migration of B cells and dendritic cells, and enhances endothelial barrier function. Results from Phase II and III clinical trials provide robust evidence of the efficacy of fingolimod in relapsing-remitting multiple sclerosis. While some caution should be exercised in terms of safety issues, the introduction of fingolimod represents a great advance in the treatment of relapsing-remitting multiple sclerosis. The pharmacologic data on fingolimod and its efficacy and safety in multiple sclerosis are reviewed in this paper.
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Affiliation(s)
- Emilio Portaccio
- Department of Neurology, University, of Florence, Florence, Italy
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FTY720 (fingolimod) efficacy in an animal model of multiple sclerosis requires astrocyte sphingosine 1-phosphate receptor 1 (S1P1) modulation. Proc Natl Acad Sci U S A 2010; 108:751-6. [PMID: 21177428 DOI: 10.1073/pnas.1014154108] [Citation(s) in RCA: 480] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Sphingosine 1-phosphate (S1P), a lysophospholipid, has gained relevance to multiple sclerosis through the discovery of FTY720 (fingolimod), recently approved as an oral treatment for relapsing forms of multiple sclerosis. Its mechanism of action is thought to be immunological through an active phosphorylated metabolite, FTY720-P, that resembles S1P and alters lymphocyte trafficking through receptor subtype S1P(1). However, previously reported expression and in vitro studies of S1P receptors suggested that direct CNS effects of FTY720 might theoretically occur through receptor modulation on neurons and glia. To identify CNS cells functionally contributing to FTY720 activity, genetic approaches were combined with cellular and molecular analyses. These studies relied on the functional assessment, based on clinical score, of conditional null mouse mutants lacking S1P(1) in CNS cell lineages and challenged by experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. All conditional null mutants displayed WT lymphocyte trafficking that responded normally to FTY720. In marked contrast, EAE was attenuated and FTY720 efficacy was lost in CNS mutants lacking S1P(1) on GFAP-expressing astrocytes but not on neurons. In situ hybridization studies confirmed that astrocyte loss of S1P(1) was the key alteration in functionally affected mutants. Reductions in EAE clinical scores were paralleled by reductions in demyelination, axonal loss, and astrogliosis. Receptor rescue and pharmacological experiments supported the loss of S1P(1) on astrocytes through functional antagonism by FTY720-P as a primary FTY720 mechanism. These data identify nonimmunological CNS mechanisms of FTY720 efficacy and implicate S1P signaling pathways within the CNS as targets for multiple sclerosis therapies.
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Noguchi K, Chun J. Roles for lysophospholipid S1P receptors in multiple sclerosis. Crit Rev Biochem Mol Biol 2010; 46:2-10. [DOI: 10.3109/10409238.2010.522975] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Miron VE, Kuhlmann T, Antel JP. Cells of the oligodendroglial lineage, myelination, and remyelination. Biochim Biophys Acta Mol Basis Dis 2010; 1812:184-93. [PMID: 20887785 DOI: 10.1016/j.bbadis.2010.09.010] [Citation(s) in RCA: 173] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Revised: 09/08/2010] [Accepted: 09/20/2010] [Indexed: 12/21/2022]
Abstract
Myelin is critical in maintaining electrical impulse conduction in the central nervous system. The oligodendrocyte is the cell type responsible for myelin production within this compartment. The mutual supply of trophic support between oligodendrocytes and the underlying axons may indicate why demyelinated axons undergo degeneration more readily; the latter contributes to the neural decline in multiple sclerosis (MS). Myelin repair, termed remyelination, occurs in acute inflammatory lesions in MS and is associated with functional recovery and clinical remittances. Animal models have demonstrated that remyelination is mediated by oligodendrocyte progenitor cells (OPCs) which have responded to chemotactic cues, migrated into the lesion, proliferated, differentiated into mature oligodendrocytes, and ensheathed demyelinated axons. The limited remyelination observed in more chronic MS lesions may reflect intrinsic properties of neural cells or extrinsic deterrents. Therapeutic strategies currently under development include transplantation of exogenous OPCs and promotion of remyelination by endogenous OPCs. All currently approved MS therapies are aimed at dampening the immune response and are not directly targeting neural processes.
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Affiliation(s)
- Veronique E Miron
- Center for Regenerative Medicine, The Queen's Medical Research Institute, University of Edinburgh, Edinburgh, EH16 4TJ, UK
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Holmström TE, Mattsson CL, Wang Y, Iakovleva I, Petrovic N, Nedergaard J. Non-transactivational, dual pathways for LPA-induced Erk1/2 activation in primary cultures of brown pre-adipocytes. Exp Cell Res 2010; 316:2664-75. [PMID: 20576526 DOI: 10.1016/j.yexcr.2010.05.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 05/21/2010] [Accepted: 05/24/2010] [Indexed: 12/17/2022]
Abstract
In many cell types, G-protein-coupled receptor (GPCR)-induced Erk1/2 MAP kinase activation is mediated via receptor tyrosine kinase (RTK) transactivation, in particular via the epidermal growth factor (EGF) receptor. Lysophosphatidic acid (LPA), acting via GPCRs, is a mitogen and MAP kinase activator in many systems, and LPA can regulate adipocyte proliferation. The mechanism by which LPA activates the Erk1/2 MAP kinase is generally accepted to be via EGF receptor transactivation. In primary cultures of brown pre-adipocytes, EGF can induce Erk1/2 activation, which is obligatory and determinant for EGF-induced proliferation of these cells. Therefore, we have here examined whether LPA, via EGF transactivation, can activate Erk1/2 in brown pre-adipocytes. We found that LPA could induce Erk1/2 activation. However, the LPA-induced Erk1/2 activation was independent of transactivation of EGF receptors (or PDGF receptors) in these cells (whereas in transformed HIB-1B brown adipocytes, the LPA-induced Erk1/2 activation indeed proceeded via EGF receptor transactivation). In the brown pre-adipocytes, LPA instead induced Erk1/2 activation via two distinct non-transactivational pathways, one G(i)-protein dependent, involving PKC and Src activation, the other, a PTX-insensitive pathway, involving PI3K (but not Akt) activation. Earlier studies showing LPA-induced Erk1/2 activation being fully dependent on RTK transactivation have all been performed in cell lines and transfected cells. The present study implies that in non-transformed systems, RTK transactivation may not be involved in the mediation of GPCR-induced Erk1/2 MAP kinase activation.
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Affiliation(s)
- Therese E Holmström
- Department of Physiology, The Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden
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60
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Miron VE, Ludwin SK, Darlington PJ, Jarjour AA, Soliven B, Kennedy TE, Antel JP. Fingolimod (FTY720) enhances remyelination following demyelination of organotypic cerebellar slices. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 176:2682-94. [PMID: 20413685 DOI: 10.2353/ajpath.2010.091234] [Citation(s) in RCA: 211] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Remyelination, which occurs subsequent to demyelination, contributes to functional recovery and is mediated by oligodendrocyte progenitor cells (OPCs) that have differentiated into myelinating cells. Therapeutics that impact remyelination in the CNS could be critical determinants of long-term functional outcome in multiple sclerosis (MS). Fingolimod is a S1P receptor modulator in MS clinical trials due to systemic anti-inflammatory properties, yet may impact cells within the CNS by crossing the blood-brain barrier. Previous studies using isolated dissociated cultures indicate that neural cells express S1P receptors and respond to receptor engagement. Our objective was to assess the effects of fingolimod on myelin-related processes within a multicellular environment that maintains physiological cell-cell interactions, using organotypic cerebellar slice cultures. Fingolimod treatment had no impact on myelin under basal conditions. Fingolimod treatment subsequent to lysolecithin-induced demyelination enhanced remyelination and process extension by OPCs and mature oligodendrocytes, while increasing microglia numbers and immunoreactivity for the astrocytic marker glial fibrillary acidic protein. The number of phagocytosing microglia was not increased by fingolimod. Using S1P receptor specific agonists and antagonists, we determined that fingolimod-induced effects on remyelination and astrogliosis were mediated primarily through S1P3 and S1P5, whereas enhanced microgliosis was mediated through S1P1 and S1P5. Taken together, these data demonstrate that fingolimod modulates multiple neuroglial cell responses, resulting in enhanced remyelination in organotypic slice cultures that maintain the complex cellular interactions of the mammalian brain.
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Affiliation(s)
- Veronique E Miron
- Neuroimmunology Unit, McGill University, Montreal Neurological Institute, 3801 University St., Montreal, QC, Canada, H3A 2B4
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Choi JW, Herr DR, Noguchi K, Yung YC, Lee CW, Mutoh T, Lin ME, Teo ST, Park KE, Mosley AN, Chun J. LPA receptors: subtypes and biological actions. Annu Rev Pharmacol Toxicol 2010; 50:157-86. [PMID: 20055701 DOI: 10.1146/annurev.pharmtox.010909.105753] [Citation(s) in RCA: 643] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Lysophosphatidic acid (LPA) is a small, ubiquitous phospholipid that acts as an extracellular signaling molecule by binding to and activating at least five known G protein-coupled receptors (GPCRs): LPA(1)-LPA(5). They are encoded by distinct genes named LPAR1-LPAR5 in humans and Lpar1-Lpar5 in mice. The biological roles of LPA are diverse and include developmental, physiological, and pathophysiological effects. This diversity is mediated by broad and overlapping expression patterns and multiple downstream signaling pathways activated by cognate LPA receptors. Studies using cloned receptors and genetic knockout mice have been instrumental in uncovering the significance of this signaling system, notably involving basic cellular processes as well as multiple organ systems such as the nervous system. This has further provided valuable proof-of-concept data to support LPA receptors and LPA metabolic enzymes as targets for the treatment of medically important diseases that include neuropsychiatric disorders, neuropathic pain, infertility, cardiovascular disease, inflammation, fibrosis, and cancer.
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Affiliation(s)
- Ji Woong Choi
- Department of Molecular Biology, Helen L. Dorris Institute for Neurological and Psychiatric Disorders, The Scripps Research Institute, La Jolla, California 92037, USA
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62
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Hagen N, Van Veldhoven PP, Proia RL, Park H, Merrill AH, van Echten-Deckert G. Subcellular origin of sphingosine 1-phosphate is essential for its toxic effect in lyase-deficient neurons. J Biol Chem 2009; 284:11346-53. [PMID: 19251691 PMCID: PMC2670140 DOI: 10.1074/jbc.m807336200] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2008] [Revised: 02/25/2009] [Indexed: 11/06/2022] Open
Abstract
Cerebellar granule cells from sphingosine 1-phosphate (S1P) lyase-deficient mice were used to study the toxicity of this potent sphingolipid metabolite in terminally differentiated postmitotic neurons. Based on earlier findings with the lyase-stable, semi-synthetic, cis-4-methylsphingosine phosphate, we hypothesized that accumulation of S1P above a certain threshold induces neuronal apoptosis. The present studies confirmed this conclusion and further revealed that for S1P to induce apoptosis in lyase-deficient neurons it must also be produced by sphingosine-kinase2 (SK2). These conclusions are based on the finding that incubation of lyase-deficient neurons with either sphingosine or S1P results in a similar elevation in cellular S1P; however, only S1P addition to the culture medium induces apoptosis. This was not due to S1P acting on the S1P receptor but to hydrolysis of S1P to sphingosine that was phosphorylated by the cells, as described before for cis-4-methylsphingosine. Although the cells produced S1P from both exogenously added sphingosine as well as sphingosine derived from exogenous S1P, the S1P from these two sources were not equivalent, because the former was primarily produced by SK1, whereas the latter was mainly formed by SK2 (as also was cis-4-methylsphingosine phosphate), based on studies in neurons lacking SK1 or SK2 activity. Thus, these investigations show that, due to the existence of at least two functionally distinct intracellular origins for S1P, exogenous S1P can be neurotoxic. In this model, S1P accumulated due to a defective lyase, however, this cause of toxicity might also be important in other cases, as illustrated by the neurotoxicity of cis-4-methylsphingosine phosphate.
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Affiliation(s)
- Nadine Hagen
- Kekulé-Institute, Life and Medical Sciences Membrane Biology and Lipid Biochemistry, University of Bonn, D-53121 Bonn, Germany
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63
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Coelho RP, Saini HS, Sato-Bigbee C. Sphingosine-1-phosphate and oligodendrocytes: from cell development to the treatment of multiple sclerosis. Prostaglandins Other Lipid Mediat 2009; 91:139-44. [PMID: 19808013 DOI: 10.1016/j.prostaglandins.2009.04.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2009] [Revised: 03/25/2009] [Accepted: 04/02/2009] [Indexed: 11/18/2022]
Abstract
Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid that mediates a wide variety of biological effects in different cells and tissues. This review discusses the effects of S1P signaling in oligodendrocytes, the myelin making cells of the central nervous system (CNS). Results from different laboratories have uncovered direct actions of S1P at different maturational stages along the oligodendroglial lineage. There is also evidence for the existence in oligodendrocytes of interactions between S1P and signaling by factors which, like neurotrophin-3 (NT-3) and platelet-derived growth factor (PDGF), have profound effects on oligodendrocyte development and myelination. Moreover, S1P signaling in oligodendrocytes may not only play an important role during normal CNS development but also offer new therapeutic avenues to stimulate remyelination in demyelinating diseases like multiple sclerosis.
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Affiliation(s)
- Rochelle P Coelho
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA
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64
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Aziziyeh AI, Li TT, Pape C, Pampillo M, Chidiac P, Possmayer F, Babwah AV, Bhattacharya M. Dual regulation of lysophosphatidic acid (LPA1) receptor signalling by Ral and GRK. Cell Signal 2009; 21:1207-17. [PMID: 19306925 DOI: 10.1016/j.cellsig.2009.03.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Revised: 02/15/2009] [Accepted: 03/12/2009] [Indexed: 11/29/2022]
Abstract
Lysophosphatidic acid (LPA) is a major constituent of blood and is involved in a variety of physiological and pathophysiological processes. LPA signals via the ubiquitously expressed G protein-coupled receptors (GPCRs), LPA(1) and LPA(2) that are specific for LPA. However, in large, the molecular mechanisms that regulate the signalling of these receptors are unknown. We show that the small GTPase RalA associates with both LPA(1) and LPA(2) in human embryonic kidney (HEK 293) cells and that stimulation of LPA(1) receptors with LPA triggers the activation of RalA. While RalA was not found to play a role in the endocytosis of LPA receptors, we reveal that LPA(1) receptor stimulation promoted Ral-dependent phospholipase C activity. Furthermore, we found that GRK2 is required for the desensitization of LPA(1) and LPA(2) and have identified a novel interaction between RalA and GRK2, which is promoted by LPA(1) receptor activity. Taken together, these results establish RalA and GRK2 as key regulators of LPA receptor signalling and demonstrate for the first time that LPA(1) activity facilitates the formation of a novel protein complex between these two proteins.
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Affiliation(s)
- Adel I Aziziyeh
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada
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65
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Skoura A, Hla T. Regulation of vascular physiology and pathology by the S1P2 receptor subtype. Cardiovasc Res 2009; 82:221-8. [PMID: 19287048 DOI: 10.1093/cvr/cvp088] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Sphingosine-1-phosphate (S1P) is now recognized as a lipid mediator that acts via G-protein-coupled receptors. S1P receptors couple to various heterotrimeric G-proteins and regulate downstream targets and ultimately cell behaviour. The prototypical S1P1 receptor is known to couple to Gi and regulates angiogenesis, vascular development, and immune cell trafficking. In this review, we focus our attention on the S1P2 receptor, which has a unique G-protein-coupling property in that it preferentially activates the G(12/13) pathway. Recent studies indicate that the S1P2 receptor regulates critical intracellular signalling pathways, such as Rho GTPase, the phosphatase PTEN, and VE-cadherin-based adherens junctions. Analysis of mutant mice has revealed the critical role of this receptor in inner ear physiology, heart and vascular development, vascular remodelling, and vascular tone, permeability, and angiogenesis in vertebrates. These studies suggest that selective modulation of S1P2 receptor function by pharmacological tools may be useful in a variety of pathological conditions.
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Affiliation(s)
- Athanasia Skoura
- Center for Vascular Biology, University of Connecticut Health Center, Farmington, CT 06030-3501, USA
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66
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Lin ME, Herr DR, Chun J. Lysophosphatidic acid (LPA) receptors: signaling properties and disease relevance. Prostaglandins Other Lipid Mediat 2009; 91:130-8. [PMID: 20331961 DOI: 10.1016/j.prostaglandins.2009.02.002] [Citation(s) in RCA: 253] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2009] [Revised: 02/13/2009] [Accepted: 02/18/2009] [Indexed: 12/20/2022]
Abstract
Lysophosphatidic acid (LPA), a water-soluble phospholipid, has gained significant attention in recent years since the discovery that it acts as a potent signaling molecule with wide-ranging effects on many different target tissues. There are currently five identified G protein-coupled receptors for LPA and more are undergoing validation. The complexity of the expression pattern and signaling properties of LPA receptors results in multiple influences on developmental, physiological, and pathological processes. This review provides a summary of LPA receptor signaling and current views on the potential involvement of this pathway in human diseases that include cardiovascular, cancer, neuropathic pain, neuropsychiatric disorders, reproductive disorders, and fibrosis. The involvement of LPA signaling in these processes implicates multiple, potential drug targets including LPA receptor subtypes and LPA metabolizing enzymes. Modulation of LPA signaling may thus provide therapeutic inroads for the treatment of human disease.
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Affiliation(s)
- Mu-En Lin
- Department of Molecular Biology, Helen L. Dorris Institute for Neurological and Psychiatric Disorders, The Scripps Research Institute, La Jolla, CA 92037, USA
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67
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Miron VE, Hall JA, Kennedy TE, Soliven B, Antel JP. Cyclical and dose-dependent responses of adult human mature oligodendrocytes to fingolimod. THE AMERICAN JOURNAL OF PATHOLOGY 2008; 173:1143-52. [PMID: 18772343 DOI: 10.2353/ajpath.2008.080478] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Fingolimod is a sphingosine-1-phosphate (S1P) analogue that has been used in clinical trials as a systemic immunomodulatory therapy for multiple sclerosis. Fingolimod readily accesses the central nervous system, raising the issue of its direct effects on neural cells. We assessed the effects of active fingolimod on dissociated cultures of mature, myelin-producing oligodendrocytes (OLGs) derived from adult human brain. Human OLGs express S1P receptor transcripts in relative abundance of S1P5>S1P3>S1P1, with undetectable levels of S1P4. Low doses of fingolimod (100 pmol/L to 1 nmol/L) induced initial membrane elaboration (2 days), subsequent retraction (4 days), and recurrence of extension with prolonged treatment (8 days). Higher doses (10 nmol/L to 1 mumol/L) caused the opposite modulation of membrane dynamics. Retraction was rescued by co-treatment with the S1P3/S1P5 pathway antagonist, suramin, and was associated with RhoA-mediated cytoskeletal signaling. Membrane elaboration was mimicked using the S1P1 agonist SEW2871. Fingolimod rescued human OLGs from serum and glucose deprivation-induced apoptosis, which was reversed with suramin co-treatment and mimicked using an S1P5 agonist. High doses of fingolimod induced an initial down-regulation of S1P5 mRNA levels relative to control (4 hours), subsequent up-regulation (2 days), and recurrent down-regulation (8 days). S1P1 mRNA levels were inversely regulated compared with S1P5. These results indicate that fingolimod modulates maturity- and species-specific OLG membrane dynamics and survival responses that are directly relevant for myelin integrity.
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Affiliation(s)
- Veronique E Miron
- Neuroimmunology Unit, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
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68
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Yuelling LM, Fuss B. Autotaxin (ATX): a multi-functional and multi-modular protein possessing enzymatic lysoPLD activity and matricellular properties. BIOCHIMICA ET BIOPHYSICA ACTA 2008; 1781:525-30. [PMID: 18485925 PMCID: PMC2564869 DOI: 10.1016/j.bbalip.2008.04.009] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Revised: 04/15/2008] [Accepted: 04/19/2008] [Indexed: 01/02/2023]
Abstract
Recent studies have established that autotaxin (ATX), also known as phosphodiesterase Ialpha/autotaxin (PD-Ialpha/ATX) or (ecto)nucleotide pyrophosphatase/phosphodiesterase 2 [(E)NPP2], represents a multi-functional and multi-modular protein. ATX was initially thought to function exclusively as a phosphodiesterase/pyrophosphatase. However, it has become apparent that this enzymatically active site, which is ultimately responsible for ATX's originally discovered property of tumor cell motility stimulation, mediates the conversion of lysophosphatidylcholine (LPC) to lysophosphatidic acid (LPA). In addition, a separate functionally active domain, here referred to as the Modulator of Oligodendrocyte Remodeling and Focal adhesion Organization (MORFO) domain, was discovered in studies analyzing the role of ATX during the differentiation of myelinating cells of the central nervous system (CNS), namely oligodendrocytes. This novel domain was found to mediate anti-adhesive, i.e. matricellular, properties and to promote morphological maturation of oligodendrocytes. In this review, we summarize our current understanding of ATX's structure-function domains and discuss their contribution to the presently known main functional roles of ATX.
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Affiliation(s)
- Larra M Yuelling
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, PO Box 980709, Richmond, VA 23298, USA
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Nogaroli L, Yuelling LM, Dennis J, Gorse K, Payne SG, Fuss B. Lysophosphatidic acid can support the formation of membranous structures and an increase in MBP mRNA levels in differentiating oligodendrocytes. Neurochem Res 2008; 34:182-93. [PMID: 18594965 DOI: 10.1007/s11064-008-9772-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Accepted: 06/03/2008] [Indexed: 11/29/2022]
Abstract
During development, differentiating oligodendrocytes progress in distinct maturation steps from premyelinating to myelinating cells. Such maturing oligodendrocytes express both the receptors mediating signaling via extracellular lysophosphatidic acid (LPA) and the major enzyme generating extracellular LPA, namely phosphodiesterase-Ialpha/autotaxin (PD-Ialpha/ATX). However, the biological role of extracellular LPA during the maturation of differentiating oligodendrocytes is currently unclear. Here, we demonstrate that application of exogenous LPA induced an increase in the area occupied by the oligodendrocytes' process network, but only when PD-Ialpha/ATX expression was down-regulated. This increase in network area was caused primarily by the formation of membranous structures. In addition, LPA increased the number of cells positive for myelin basic protein (MBP). This effect was associated by an increase in the mRNA levels coding for MBP but not myelin oligodendrocyte glycoprotein (MOG). Taken together, these data suggest that LPA may play a crucial role in regulating the later stages of oligodendrocyte maturation.
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Affiliation(s)
- Luciana Nogaroli
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, PO Box 980709, Richmond, VA 23298, USA
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70
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Foster CA, Mechtcheriakova D, Storch MK, Balatoni B, Howard LM, Bornancin F, Wlachos A, Sobanov J, Kinnunen A, Baumruker T. FTY720 rescue therapy in the dark agouti rat model of experimental autoimmune encephalomyelitis: expression of central nervous system genes and reversal of blood-brain-barrier damage. Brain Pathol 2008; 19:254-66. [PMID: 18540945 DOI: 10.1111/j.1750-3639.2008.00182.x] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
FTY720 (fingolimod) is an oral sphingosine-1 phosphate (S1P) receptor modulator in phase III development for the treatment of multiple sclerosis. To further investigate its mode of action, we analyzed gene expression in the central nervous system (CNS) during experimental autoimmune encephalomyelitis (EAE). FTY720 downregulated inflammatory genes in addition to vascular adhesion molecules. It decreased the matrix metalloproteinase gene MMP-9 and increased its counterregulator--tissue inhibitor of metalloproteinase, TIMP-1--resulting in a proteolytic balance that favors preservation of blood-brain-barrier (BBB) integrity. Furthermore, FTY720 reduced S1P lyase that increases the S1P concentration in the brain, in line with a marked reversal of neurological deficits and raising the possibility for enhanced triggering of S1P receptors on resident brain cells. This is accompanied by an increase in S1P(1) and S1P(5) in contrast with the attenuation of S1P(3) and S1P(4). Late-stage rescue therapy with FTY720, even up to 1 month after EAE onset, reversed BBB leakiness and reduced demyelination, along with normalization of neurologic function. Our results indicate rapid blockade of ongoing disease processes by FTY720, and structural restoration of the CNS parenchyma, which is likely caused by the inhibition of autoimmune T cell infiltration and direct modulation of microvascular and/or glial cells.
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Affiliation(s)
- Carolyn A Foster
- Novartis Institutes for BioMedical Research, Brunner Strasse 59, Vienna, Austria.
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71
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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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72
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Miron VE, Jung CG, Kim HJ, Kennedy TE, Soliven B, Antel JP. FTY720 modulates human oligodendrocyte progenitor process extension and survival. Ann Neurol 2008; 63:61-71. [PMID: 17918267 DOI: 10.1002/ana.21227] [Citation(s) in RCA: 207] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE FTY720, a sphingosine-1-phosphate (S1P) receptor agonist that crosses the blood-brain barrier, is a potential immuno-therapy for multiple sclerosis. Our objective was to assess the effect of FTY720 on process extension, differentiation, and survival of human oligodendrocyte progenitor cells (OPCs), and link the functional effects with S1P receptor expression and signaling. METHODS Functional assays and receptor expression studies were conducted on A2B5+ OPCs derived from the human fetal central nervous system. Cells were treated with physiologically relevant concentrations of the active phosphorylated form of FTY720. S1P receptor/signaling modulators were used to elucidate the basis of the FTY720-induced functional responses. RESULTS Short-term (1 day) FTY720 treatment caused initial process retraction that was reversed by uncoupling S1P3 and 5 from their G protein using suramin, and with a Rho-kinase inhibitor H1152. Retraction was associated with RhoA-mediated cytoskeletal signaling and with inhibition of OPC differentiation into more mature phenotypes. Continued FTY720 treatment (2 days) induced process extension and enhanced cell survival associated with increased extracellular signal-regulated kinases 1 and 2 phosphorylation, mimicked with the S1P1-specific agonist SEW2871, but not reversed with suramin. Quantitative real-time polymerase chain reaction showed that FTY720 induced reciprocal and cyclic modulation of S1P1 and S1P5 messenger RNA levels. The observed initial downregulation of S1P5 and subsequently of S1P1 messenger RNA supports functional responses being mediated sequentially by S1P5- and later S1P1-associated signaling. INTERPRETATION FTY720 induces time-dependent modulation of S1P receptors on human OPCs with consequent functional responses that are directly relevant for the remyelination process.
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Affiliation(s)
- Veronique E Miron
- Neuroimmunology Unit, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
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73
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Klatt J, Hartung HP, Hohlfeld R. [FTY720 (Fingolimod) as a new therapeutic option for multiple sclerosis]. DER NERVENARZT 2007; 78:1200-8. [PMID: 17668161 DOI: 10.1007/s00115-007-2298-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
All currently available therapeutic options for multiple sclerosis have to be administered parenterally. Several oral substances are currently in the late clinical development stage. One of them, FTY720 (also known as fingolimod) is highlighted in this review. The biological effects of FTY720 are presented as well as animal data and first clinical data from a phase II trial in multiple sclerosis patients. The effects of FTY720 are based on an innovative approach and apparently target several key elements in the pathogenesis of multiple sclerosis. The first clinical data with FTY720 show very promising results, with a relapse reduction of over 50% compared to placebo and an acceptable safety profile. These results currently await confirmation in two international phase III studies which are recruiting patients worldwide.
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Affiliation(s)
- J Klatt
- Novartis Pharma GmbH Nürnberg
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74
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Hu J, Strauch P, Rubtsov A, Donovan EE, Pelanda R, Torres RM. Lsc activity is controlled by oligomerization and regulates integrin adhesion. Mol Immunol 2007; 45:1825-36. [PMID: 18157933 DOI: 10.1016/j.molimm.2007.11.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Revised: 11/01/2007] [Accepted: 11/04/2007] [Indexed: 01/20/2023]
Abstract
Lsc is a hematopoietic-restricted protein that functions as an effector of G alpha(12/13)-associated G-protein coupled receptors that activates RhoA. In the absence of Lsc leukocytes exhibit impaired migration and B lymphocytes inefficiently resolve integrin-mediated adhesion. Here, we demonstrate that Lsc exists physiologically in primary B lymphocytes as a large molecular weight complex resembling a homo-tetramer. Interfering with the assembly of this large molecular weight Lsc oligomer results in the activation of both Lsc functional activities and leads to cell rounding and inhibition of integrin-mediated adhesion. During cell migration on integrin ligands we find Lsc localizes predominantly toward the rear of migrating cells where we suggest it activates RhoA to resolve integin-mediated adhesion. Together these data demonstrate that Lsc regulates integrin-mediated adhesive events at the trailing edge of migrating cells.
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Affiliation(s)
- Jiancheng Hu
- Integrated Department of Immunology, University of Colorado Health Sciences Center and National Jewish Medical and Research Center, Denver, CO 80206, USA
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75
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Jung CG, Kim HJ, Miron VE, Cook S, Kennedy TE, Foster CA, Antel JP, Soliven B. Functional consequences of S1P receptor modulation in rat oligodendroglial lineage cells. Glia 2007; 55:1656-67. [PMID: 17876806 DOI: 10.1002/glia.20576] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Fingolimod (FTY720) and its phosphorylated form FTY720P are modulators of sphingosine-1-phosphate (S1P) receptors, which are G-protein coupled receptors linked to cell migration and vascular maturation. The efficacy of FTY720 in autoimmune diseases such as multiple sclerosis and its animal models has been attributed to its inhibition of lymphocyte trafficking to target organs. In this study, we examined the role of S1P receptors in cultured rat oligodendrocytes (OLGs) and OLG progenitor cells (OPCs) using the active phosphorylated form of FTY720. We found that (1) FTY720P improves the survival of neonatal rat OLGs during serum withdrawal, which is associated with the phosphorylation of extracellular signal regulated kinases (ERK1/2) and Akt; (2) FTY720P regulates OPC differentiation into OLGs in a concentration-dependent manner; and (3) S1P receptors are differentially modulated by platelet-derived growth factor (PDGF) resulting in downregulation of S1P5 and upregulation of S1P1 in OPCs. In addition, siRNA studies revealed that S1P1 participates in PDGF-induced OPC mitogenesis. We conclude that S1P1 and S1P5 serve different functions during oligodendroglial development, and possibly during remyelination.
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Affiliation(s)
- C G Jung
- Department of Neurology, University of Chicago, Chicago, Illinois 60637, USA
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76
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Dennis J, White MA, Forrest AD, Yuelling LM, Nogaroli L, Afshari FS, Fox MA, Fuss B. Phosphodiesterase-Ialpha/autotaxin's MORFO domain regulates oligodendroglial process network formation and focal adhesion organization. Mol Cell Neurosci 2007; 37:412-24. [PMID: 18164210 DOI: 10.1016/j.mcn.2007.10.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Revised: 10/23/2007] [Accepted: 10/30/2007] [Indexed: 10/22/2022] Open
Abstract
Development of a complex process network by maturing oligodendrocytes is a critical but currently poorly characterized step toward myelination. Here, we demonstrate that the matricellular oligodendrocyte-derived protein phosphodiesterase-Ialpha/autotaxin (PD-Ialpha/ATX) and especially its MORFO domain are able to promote this developmental step. In particular, the single EF hand-like motif located within PD-Ialpha/ATX's MORFO domain was found to stimulate the outgrowth of higher order branches but not process elongation. This motif was also observed to be critical for the stimulatory effect of PD-Ialpha/ATX's MORFO domain on the reorganization of focal adhesions located at the leading edge of oligodendroglial protrusions. Collectively, our data suggest that PD-Ialpha/ATX promotes oligodendroglial process network formation and expansion via the cooperative action of multiple functional sites located within the MORFO domain and more specifically, a novel signaling pathway mediated by the single EF hand-like motif and regulating the correlated events of process outgrowth and focal adhesion organization.
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Affiliation(s)
- Jameel Dennis
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA
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77
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Hoelzinger DB, Demuth T, Berens ME. Autocrine factors that sustain glioma invasion and paracrine biology in the brain microenvironment. J Natl Cancer Inst 2007; 99:1583-93. [PMID: 17971532 DOI: 10.1093/jnci/djm187] [Citation(s) in RCA: 279] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Invasion is a defining hallmark of glioblastoma multiforme, just as metastasis characterizes other high-grade tumors. Glial tumors invariably recur due to the regrowth of invasive cells, which are unaffected by standard treatment modalities. Drivers of glioma invasion include autocrine signals propagated by secreted factors that signal through receptors on the tumor. These secreted factors are able to diffuse through the peritumoral stroma, thereby influencing parenchymal cells that surround the tumor mass. Here we describe various autocrine motility factors that are expressed by invasive glioma cells and explore the effects that they may have on normal cells present in the path of invasion. Conversely, normal brain parenchymal cells secrete ligands that can stimulate receptors on invasive glioma cells and potentially facilitate glioma invasion or create a permissive microenvironment for malignant progression. Parallel observations have been made for solid tumors of epithelial origin, in which parenchymal and stromal cells either support or suppress tumor invasion. Most autocrine and paracrine interactions involved in glioma invasion constitute known signaling systems in stages of central nervous system development that involve the migration of precursor cells that populate the developing brain. Key paracrine interactions between glioma cells and the brain microenvironment can influence glioma pathobiology and therefore contribute to its poor prognosis. Current therapies for glioma that could have an impact on paracrine communication between tumors and normal cells are discussed. We suggest that cells in the normal brain parenchyma be considered as potential targets for adjuvant therapies to control glioma growth because such cells are less likely to develop resistance than glioma cells.
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Affiliation(s)
- Dominique B Hoelzinger
- Cancer and Cell Biology Division, Translational Genomics Research Institute, 445 North Fifth Street, Phoenix, AZ 85004, USA
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78
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Chen J, Baydoun AR, Xu R, Deng L, Liu X, Zhu W, Shi L, Cong X, Hu S, Chen X. Lysophosphatidic acid protects mesenchymal stem cells against hypoxia and serum deprivation-induced apoptosis. Stem Cells 2007; 26:135-45. [PMID: 17932426 DOI: 10.1634/stemcells.2007-0098] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Bone marrow-derived mesenchymal stem cells (MSCs) have shown great promise for cardiac repair. However, poor viability of transplanted MSCs within the ischemic heart has limited their therapeutic potential. Our previous studies have documented that hypoxia and serum deprivation (hypoxia/SD), induced MSCs apoptosis through the mitochondrial apoptotic pathway. Since serum lysophosphatidic acid (LPA) levels are known to be significantly elevated after acute myocardial infarction and that LPA enhanced survival of other cell systems, we embarked on determining whether LPA protects MSCs against hypoxia/SD-induced apoptosis. We have also investigated the potential mechanism(s) that may mediate such actions of LPA. All experiments were carried out on rat bone marrow MSCs. Apoptosis was induced by exposure of cells to hypoxia/SD in a sealed GENbox hypoxic chamber. Effects of LPA were investigated in the absence and presence of inhibitors that target either G(i)proteins, the mitogen activated protein kinases ERK1/2, or phosphoinositide 3-kinase (PI3K). The data obtained showed that hypoxia/SD-induced apoptosis was significantly attenuated by LPA through Gi-coupled LPA(1) receptors linked to the downstream ERK1/2 and PI3K/Akt signaling pathways that function in parallel. Additional studies have demonstrated that hypoxia/SD-induced activation of mitochondrial dysfunction was virtually abolished by LPA treatment and that inhibition of the LPA(1) receptor, Gi proteins, the PI3K/Akt pathway, or ERKs effectively reversed this protective action of LPA. Taken together, our findings indicate that LPA is a novel, potent survival factor for MSCs and this may prove to be of considerable therapeutic significance in terms of exploiting MSC-based therapy in the infracted myocardium.
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Affiliation(s)
- Jinghai Chen
- Research Center for Cardiovascular Regenerative Medicine, The Ministry of Health of China, Cardiovascular Institute and Fu Wai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China
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79
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Hoelzinger DB, Nakada M, Demuth T, Rosensteel T, Reavie LB, Berens ME. Autotaxin: a secreted autocrine/paracrine factor that promotes glioma invasion. J Neurooncol 2007; 86:297-309. [PMID: 17928955 DOI: 10.1007/s11060-007-9480-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Accepted: 10/01/2007] [Indexed: 11/24/2022]
Abstract
Glioblastoma multiforme (GBM) is inherently invasive, and it is from the invasive cell population that the tumor recurs. The GBM invasion transcriptome reveals over-expression of various autocrine factors that could act as motility drivers, such as autotaxin (ATX). Some of these factors could also have paracrine roles, modulating the behavior of cells in the peri-tumoral brain parenchyma. ATX generates lysophosphatidic acid (LPA), which signals through LPA receptors expressed by GBM as well as in astrocytes, oligodendrocytes (ODC) and microglia; their activation manifest cell specific effects. ATX stimulates invasion of GBM cells in vitro and ex vivo invasion assays. ATX activity enhances GBM adhesion in cells expressing the LPA1 receptor, as well as stimulating rac activation. GBM secreted ATX can also have paracrine effects: ATX activity results in reduced ODC adhesion. ODC monolayer invasion showed that U87 and U251 GBM cells expressing ATX invaded through an ODC monolayer significantly more than cells depleted of ATX or cells expressing inactive ATX, suggesting that GBM cells secreting ATX find ODCs less of a barrier than cells that do not express ATX. Secreted factors that drive GBM invasion can have autocrine and paracrine roles; one stimulates GBM motility and the other results in ODC dis-adhesion.
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Affiliation(s)
- Dominique B Hoelzinger
- Cancer and Cell Biology Division, Translational Genomics Research Institute, 445 North 5th Street, 5th floor, Phoenix, AZ 85004, USA
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80
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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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81
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Foster CA, Howard LM, Schweitzer A, Persohn E, Hiestand PC, Balatoni B, Reuschel R, Beerli C, Schwartz M, Billich A. Brain penetration of the oral immunomodulatory drug FTY720 and its phosphorylation in the central nervous system during experimental autoimmune encephalomyelitis: consequences for mode of action in multiple sclerosis. J Pharmacol Exp Ther 2007; 323:469-75. [PMID: 17682127 DOI: 10.1124/jpet.107.127183] [Citation(s) in RCA: 258] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
FTY720 [2-amino-2-[2-(4-octylphenyl) ethyl]propane-1,3-diol hydrochloride] is an oral sphingosine-1-phosphate receptor modulator under development for the treatment of multiple sclerosis (MS). The drug is phosphorylated in vivo by sphingosine kinase 2 to its bioactive form, FTY720-P. Although treatment with FTY720 is accompanied by a reduction of the peripheral lymphocyte count, its efficacy in MS and experimental autoimmune encephalomyelitis (EAE) may be due to additional, direct effects in the central nervous system (CNS). We now show that FTY720 localizes to the CNS white matter, preferentially along myelin sheaths. Brain trough levels of FTY720 and FTY720-P in rat EAE are of the same magnitude and dose dependently increase; they are in the range of 40 to 540 ng/g in the brain tissue at efficacious doses and exceed blood concentrations severalfold. In a rat model of chronic EAE, prolonged treatment with 0.03 mg/kg was efficacious, but limiting the dosing period failed to prevent EAE despite a significant decrease in blood lymphocytes. FTY720 effectiveness is likely due to a culmination of mechanisms involving reduction of autoreactive T cells, neuroprotective influence of FTY720-P in the CNS, and inhibition of inflammatory mediators in the brain.
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82
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Zeng W, Zhang Z. Lysophosphatidic acid induces astrocyte proliferation in hippocampus slices partially through activating extracellular signal-regulated kinases. RESEARCH ON CHEMICAL INTERMEDIATES 2007. [DOI: 10.1163/156856707782565859] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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83
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Osinde M, Mullershausen F, Dev KK. Phosphorylated FTY720 stimulates ERK phosphorylation in astrocytes via S1P receptors. Neuropharmacology 2007; 52:1210-8. [PMID: 17379261 DOI: 10.1016/j.neuropharm.2006.11.010] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2006] [Revised: 11/08/2006] [Accepted: 11/27/2006] [Indexed: 01/23/2023]
Abstract
Sphingosine-1-phosphate receptors (S1P1-5) are activated by the endogenous agonist S1P and are expressed in the central nervous system. In astrocytes, activation of S1P receptors leads to phosphorylation of extracellular-signal regulated kinase (ERK), a signaling cascade which plays intimate roles in cell proliferation. Fingolimod (FTY720) is in phase III clinical trials for the treatment of multiple sclerosis and its phosphorylated version (FTY720P) activates S1P receptors. We examined the effects of FTY720P on ERK phosphorylation and determined which S1P receptor subtype(s) mediated this signaling event. FTY720P augmented ERK phosphorylation in cortical cultures prepared from embryonic day 18 rat brains and was blocked by an MEK inhibitor or by pertussis toxin. Co-localisation of phosphorylated ERK occurred in glial fibrillary acidic protein (GFAP) positive astrocytes but not neurons or oligodendrocytes. Furthermore, FTY720P stimulated ERK phosphorylation in highly enriched astrocyte cultures made from postnatal day 2 rat cortices. The effects of FTY720P were mimicked by selective S1P1 receptor agonists and blocked by S1P1 receptor antagonists. Collectively, these results demonstrate that FTY720P mediates ERK phosphorylation in astrocytes via the activation of S1P1 receptors.
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Affiliation(s)
- Maribel Osinde
- Department of Neuroscience, Novartis Institutes for BioMedical Research, Unit of Neurodegeneration, Novartis Pharma, WSJ-386.7.43 Lichtstrasse 35, CH-4002 Basel, Switzerland
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84
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Park KS, Kim MK, Lee HY, Kim SD, Lee SY, Kim JM, Ryu SH, Bae YS. S1P stimulates chemotactic migration and invasion in OVCAR3 ovarian cancer cells. Biochem Biophys Res Commun 2007; 356:239-44. [PMID: 17349972 DOI: 10.1016/j.bbrc.2007.02.112] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Accepted: 02/22/2007] [Indexed: 11/24/2022]
Abstract
OVCAR3 ovarian cancer cells express three sphingosine 1-phosphate (S1P) receptors, S1P(1), S1P(2), and S1P(3), but not S1P(4). Stimulation of OVCAR3 cells with S1P induced intracellular calcium increases, which were partly inhibited by VPC 23019 (an S1P(1/3) antagonist). S1P-induced calcium increases were mediated by phospholipase C and pertussis toxin (PTX)-sensitive G-proteins in OVCAR3 cells. S1P stimulated extracellular signal-regulated kinase, p38 kinase, and Akt which were inhibited by PTX. S1P-stimulated chemotactic migration of OVCAR3 cells in a PTX-sensitive manner, indicating crucial role of G(i) protein(s) in the process. S1P-induced chemotactic migration of OVCAR3 cells was completely inhibited by LY294002 and SB203580. Pretreatment of VPC 23019 (an S1P(1/3) antagonist) completely inhibited S1P-induced chemotaxis. S1P also induced invasion of OVCAR3 cells, which was also inhibited by VPC 23019. Taken together, this study suggests that S1P stimulate chemotactic migration and cellular invasion, and VPC 23019-sensitive S1P receptor(s) might be involved in the processes.
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Affiliation(s)
- Kyoung Sun Park
- Department of Biochemistry, College of Medicine, Dong-A University, Busan 602-714, Republic of Korea
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85
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Novgorodov AS, El-Alwani M, Bielawski J, Obeid LM, Gudz TI. Activation of sphingosine-1-phosphate receptor S1P5 inhibits oligodendrocyte progenitor migration. FASEB J 2007; 21:1503-14. [PMID: 17255471 DOI: 10.1096/fj.06-7420com] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Sphingosine-1-phosphate (S1P) acts as an extracellular ligand for a family of G-protein coupled receptors that are crucial in cell migration. S1P5 is exclusively expressed in oligodendrocytes and oligodendrocyte precursor cells (OPCs), which migrate considerable distances during brain development. The current studies suggest a physiological role for S1P and S1P5 in regulation of OPC migration. mRNA expression levels of S1P2 and S1P5 are comparable in OPCs, but S1P binding specifically to the S1P5 receptor blocked OPC migration (IC50=29 nM). Thus, knocking down S1P5 using siRNA prevented the S1P-induced decrease in OPC migration, whereas knocking down S1P2 did not have any effect. S1P-induced modulation of OPC migration was insensitive to pertussis toxin, suggesting that S1P5-initiated signaling is not mediated by the G alpha(i)-protein coupled pathway. Furthermore, S1P5 appears to engage the G alpha(12/13) protein coupled Rho/ROCK signaling pathway to impede OPC migration. To modulate OPC motility, extracellular S1P could be derived from the export of intracellular S1P generated in response to glutamate treatment of OPCs. These studies suggest that S1P could be a part of the neuron-oligodendroglial communication network regulating OPC migration and may provide directional guidance cues for migrating OPCs in the developing brain.
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Affiliation(s)
- Alexander S Novgorodov
- Department of Neuroscience, Medical University of South Carolina, 114 Doughty St. Charleston, SC 29425, USA
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86
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Bhat NR, Zhang P, Mohanty SB. p38 MAP kinase regulation of oligodendrocyte differentiation with CREB as a potential target. Neurochem Res 2007; 32:293-302. [PMID: 17235686 DOI: 10.1007/s11064-006-9274-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2006] [Accepted: 09/06/2006] [Indexed: 10/23/2022]
Abstract
Despite a substantial understanding of the factors regulating oligodendrocyte differentiation, the signaling mechanisms involved in this process are not well-understood. This study elaborates on the findings (Bhat NR, Zhang P (1997) FASEB J 11:A925; Baron W, Metz B, Bansal R, Hoekstra D, de Vries H (2000) Mol Cell Neurosci 15:314-329) of a role for p38 MAP kinase signaling in oligodendrocyte differentiation and myelin gene expression. When proliferating oligodendrocyte progenitors were switched to a growth factor-free differentiation medium, there was a rapid activation of p38 kinase that correlated with an increased phosphorylation of CREB, a down-stream target and a factor involved in oligodendrocyte differentiation. Addition of forskolin, a known inducer of intracellular c-AMP and of oligodendrocyte differentiation, also stimulated CREB phosphorylation in a p38 kinase dependent way. Pharmacological inhibition of p38 interfered with the morphological and antigenic changes associated with differentiating oligodendrocytes as well as with the developmental and forskolin-induced expression of myelin basic protein, thereby supporting an essential role for p38 MAPK pathway in oligodendrocyte differentiation.
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Affiliation(s)
- Narayan R Bhat
- Department of Neurosciences, Medical University of South Carolina, 171 Ashley Avenue, Charleston, SC 29425, USA.
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87
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Fujishiro J, Kudou S, Iwai S, Takahashi M, Hakamata Y, Kinoshita M, Iwanami S, Izawa S, Yasue T, Hashizume K, Murakami T, Kobayashi E. Use of sphingosine-1-phosphate 1 receptor agonist, KRP-203, in combination with a subtherapeutic dose of cyclosporine A for rat renal transplantation. Transplantation 2006; 82:804-12. [PMID: 17006328 DOI: 10.1097/01.tp.0000232687.78242.cd] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND We demonstrate the long-term effectiveness of KRP-203 treatment in combination with a subtherapeutic dose of cyclosporine A (CsA) on rat renal allografts. METHODS We tested the effect of KRP-203 in combination with CsA using a rat skin allograft model. The Pharmacokinetic interaction between CsA and KRP-203 was evaluated. The selectivity of KRP-203 for sphingosine-1-phosphate (S1P)1 and S1P3 receptors were investigated in vitro. Heart rate alteration following bolus injection of phosphorylated KRP-203 (KRP-203-P) or FTY720 (FTY720-P) was also monitored in rats. Finally, the long-term effectiveness of KRP-203 in conjunction with a low dose of CsA was investigated in a rat renal transplantation model. RESULTS Administration of KRP-203 with CsA prolonged skin allograft survival. KRP-203 and CsA had no effect on the pharmacokinetics of the other. While FTY720-P activated both S1P1 and S1P3 receptors, KRP-203-P selectively activated S1P1, but not the S1P3 receptor (EC50:>1000 nM). Compared to FTY720-P, a tenfold higher dose of KRP-203-P was necessary to induce transient bradycardia. With a low dose of CsA (1 mg/kg/day), KRP-203 (0.3 mg/kg/day) significantly prolonged renal allograft survival (P<0.05, survival time: 9.8 days (CsA) vs. >27.4 days (CsA+KRP)). Although a higher dose of CsA (3 mg/kg/day) alone kept recipients alive, this caused severe renal graft dysfunction. Use of KRP-203 (3 mg/kg/day) in conjunction with CsA markedly improved graft function (P<0.05, creatinine clearance: 0.41+/-0.25 ml/min [CsA] vs. 1.15+/-0.16 ml/min [CsA+KRP]). CONCLUSIONS The selectivity of KRP-203 for S1P1 reduces the risk of bradycardia, and the combination therapy of KRP-203 with CsA represents a safe and effective strategy for use in renal transplantation.
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Affiliation(s)
- Jun Fujishiro
- Division of Organ Replacement Research, Center for Molecular Medicine, Jichi Medical University, Tochigi, Japan
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88
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Meyer zu Heringdorf D, Jakobs KH. Lysophospholipid receptors: signalling, pharmacology and regulation by lysophospholipid metabolism. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1768:923-40. [PMID: 17078925 DOI: 10.1016/j.bbamem.2006.09.026] [Citation(s) in RCA: 262] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2006] [Accepted: 09/28/2006] [Indexed: 12/17/2022]
Abstract
The lysophospholipids, sphingosine-1-phosphate (S1P), lysophosphatidic acid (LPA), sphingosylphosphorylcholine (SPC) and lysophosphatidylcholine (LPC), activate diverse groups of G-protein-coupled receptors that are widely expressed and regulate decisive cellular functions. Receptors of the endothelial differentiation gene family are activated by S1P (S1P(1-5)) or LPA (LPA(1-3)); two more distantly related receptors are activated by LPA (LPA(4/5)); the GPR(3/6/12) receptors have a high constitutive activity but are further activated by S1P and/or SPC; and receptors of the OGR1 cluster (OGR1, GPR4, G2A, TDAG8) appear to be activated by SPC, LPC, psychosine and/or protons. G-protein-coupled lysophospholipid receptors regulate cellular Ca(2+) homoeostasis and the cytoskeleton, proliferation and survival, migration and adhesion. They have been implicated in development, regulation of the cardiovascular, immune and nervous systems, inflammation, arteriosclerosis and cancer. The availability of S1P and LPA at their G-protein-coupled receptors is regulated by enzymes that generate or metabolize these lysophospholipids, and localization plays an important role in this process. Besides FTY720, which is phosphorylated by sphingosine kinase-2 and then acts on four of the five S1P receptors of the endothelial differentiation gene family, other compounds have been identified that interact with more ore less selectivity with lysophospholipid receptors.
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89
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Kappos L, Antel J, Comi G, Montalban X, O'Connor P, Polman CH, Haas T, Korn AA, Karlsson G, Radue EW. Oral fingolimod (FTY720) for relapsing multiple sclerosis. N Engl J Med 2006; 355:1124-40. [PMID: 16971719 DOI: 10.1056/nejmoa052643] [Citation(s) in RCA: 791] [Impact Index Per Article: 43.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Fingolimod (FTY720) is a new oral immunomodulating agent under evaluation for the treatment of relapsing multiple sclerosis. METHODS We randomly assigned 281 patients to receive oral fingolimod, at a dose of 1.25 mg or 5.0 mg, or a placebo once daily, and we followed these patients for 6 months with magnetic resonance imaging (MRI) and clinical evaluations (core study, months 0 to 6). The primary end point was the total number of gadolinium-enhanced lesions recorded on T(1)-weighted MRI at monthly intervals for 6 months. In an extension study in which the investigators and patients remained unaware of the dose assignments (months 7 to 12), patients who received placebo underwent randomization again to one of the fingolimod doses. RESULTS A total of 255 patients completed the core study. The median total number of gadolinium-enhanced lesions on MRI was lower with 1.25 mg of fingolimod (1 lesion, P<0.001) and 5.0 mg of fingolimod (3 lesions, P=0.006) than with placebo (5 lesions). The annualized relapse rate was 0.77 in the placebo group, as compared with 0.35 in the group given 1.25 mg of fingolimod (P=0.009) and 0.36 in the group given 5.0 mg of fingolimod (P=0.01). For the 227 patients who completed the extension study, the number of gadolinium-enhanced lesions and relapse rates remained low in the groups that received continuous fingolimod, and both measures decreased in patients who switched from placebo to fingolimod. Adverse events included nasopharyngitis, dyspnea, headache, diarrhea, and nausea. Clinically asymptomatic elevations of alanine aminotransferase levels were more frequent with fingolimod (10 to 12%, vs. 1% in the placebo group). One case of the posterior reversible encephalopathy syndrome occurred in the 5.0-mg group. Fingolimod was also associated with an initial reduction in the heart rate and a modest decrease in the forced expiratory volume in 1 second. CONCLUSIONS In this proof-of-concept study, fingolimod reduced the number of lesions detected on MRI and clinical disease activity in patients with multiple sclerosis. Evaluation in larger, longer-term studies is warranted. (Clinicaltrials.gov numbers, NCT00333138 [core study] and NCT00235430 [ClinicalTrials.gov] [extension].).
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Affiliation(s)
- Ludwig Kappos
- Department of Neurology, University Hospital, Basel, Switzerland.
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90
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Oh DY, Yon C, Oh KJ, Lee KS, Han JS. Hippocalcin increases phospholipase D2 expression through extracellular signal-regulated kinase activation and lysophosphatidic acid potentiates the hippocalcin-induced phospholipase D2 expression. J Cell Biochem 2006; 97:1052-65. [PMID: 16294323 DOI: 10.1002/jcb.20665] [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] [Indexed: 11/08/2022]
Abstract
We have previously isolated a 22 kDa protein from a rat brain which was found to be involved in activating phospholipsae D (PLD), and identified the protein as hippocalcin through sequence analysis. Nevertheless, the function of hippocalcin for PLD activation still remains to be resolved. Here, we proposed that hippocalcin was involved in extracellular signal-regulated kinase (ERK)-mediated PLD2 expression. To elucidate a role of hippocalcin, we made hippocalcin transfected NIH3T3 cells and showed that the expression of PLD2 and basal PLD activity were increased in hippocalcin transfected cells. We performed PLD assay with dominant negative PLD2 (DN-PLD2) and hippocalcin co-transfected cells. DN-PLD2 suppressed increase of basal PLD activity in hippocalcin transfected cells, suggesting that increased basal PLD activity is due to PLD2 over-expression. Hippocalcin is a Ca2+-binding protein, which is expressed mainly in the hippocampus. Since it is known that lysophosphatidic acid (LPA) increases intracellular Ca2+, we investigated the possible role of hippocalcin in the LPA-induced elevation of intracellular Ca2+. When the intracellular Ca2+ level was increased by LPA, hippocalcin was translocated to the membrane after LPA treatment in hippocalcin transfected cells. In addition, treatment with LPA in hippocalcin transfected cells markedly potentiated PLD2 expression and showed morphological changes of cell shape suggesting that increased PLD2 expression acts as one of the major factors to cause change of cell shape by making altered membrane lipid composition. Hippocalcin-induced PLD2 expression potentiated by LPA in hippocalcin transfected cells was inhibited by a PI-PLC inhibitor, U73122 and a chelator of intracellular Ca2+, BAPTA-AM suggesting that activation of hippocalcin caused by increased intracellular Ca2+ is important to induce over-expression of PLD2. However, downregulation of PKC and treatment of a chelator of extracellular Ca2+, EGTA had little or no effect on the inhibition of hippocalcin-induced PLD2 expression potentiated by LPA in the hippocalcin transfected cells. Interestingly, when we over-express hippocalcin, ERK was activated, and treatment with LPA in hippocalcin transfected cells significantly potentiated ERK activation. Specific inhibition of ERK dramatically abolished hippocalcin-induced PLD2 expression. Taken together, these results suggest for the first time that hippocalcin can induce PLD2 expression and LPA potentiates hippocalcin-induced PLD2 expression, which is mediated by ERK activation.
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Affiliation(s)
- Doo-Yi Oh
- Institute of Biomedical Science and Department of Biochemistry and Molecular Biology, College of Medicine, Hanyang University, 17 Haengdang-Dong, Seoul 133-791, Korea
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91
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Bassi R, Anelli V, Giussani P, Tettamanti G, Viani P, Riboni L. Sphingosine-1-phosphate is released by cerebellar astrocytes in response to bFGF and induces astrocyte proliferation through Gi-protein-coupled receptors. Glia 2006; 53:621-30. [PMID: 16470810 DOI: 10.1002/glia.20324] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The mitogenic role of sphingosine-1-phosphate (S1P) and its involvement in basic fibroblast growth factor (bFGF)-induced proliferation were examined in primary cultures of cerebellar astrocytes. Exposure to bFGF resulted in a rapid increase of extracellular S1P formation, bFGF inducing astrocytes to release S1P, but not sphingosine kinase, in the extracellular milieu. The SK inhibitor N,N-dimethylsphingosine inhibited S1P release as well as bFGF-induced growth stimulation. S1P application in quiescent astrocytes caused a dose-dependent increase in DNA synthesis. This gliotrophic effect was induced by a brief exposure to low nanomolar S1P, mimicked by the S1P receptor agonist dihydro-S1P, and inhibited by pertussis toxin (PTX), an inactivator of G(i)/G(o)-proteins. S1P also induced activation of extracellular signal-regulated kinase that was inhibited again by PTX. Moreover, the S1P lyase inhibitor 4-deoxypyridoxine induced the cellular accumulation of S1P but did not affect DNA synthesis. These results support the view that S1P exerted a mitogenic effect on cerebellar astrocytes extracellularly, most likely through cell surface S1P receptors. In agreement, mRNAs for S1P1, S1P2, and S1P3 receptors are expressed in cerebellar astrocytes (Anelli et al., 2005. J Neurochem 92:1204-1215). Ceramide, a negative regulator of astrocyte proliferation and down-regulated by bFGF (Riboni et al., 2002. Cerebellum 1:129-135), efficiently inhibited S1P-induced proliferation. The S1P action appears to be part of an autocrine/paracrine cascade stimulated by bFGF and, together with ceramide down-regulation, essential for astrocytes to respond to bFGF. The results suggest that S1P and bFGF/S1P may play an important role in physiopathological glial proliferation, such as brain development, reactive gliosis and brain tumor formation.
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Affiliation(s)
- Rosaria Bassi
- Department of Medical Chemistry, Biochemistry and Biotechnology, University of Milan, LITA-Segrate, Milan, Italy
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92
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Dennis J, Nogaroli L, Fuss B. Phosphodiesterase-Ialpha/autotaxin (PD-Ialpha/ATX): a multifunctional protein involved in central nervous system development and disease. J Neurosci Res 2006; 82:737-42. [PMID: 16267828 DOI: 10.1002/jnr.20686] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Phosphodiesterase-Ialpha/autotaxin (PD-Ialpha/ATX) was originally identified as a cell-motility-stimulating factor secreted by a variety of tumor cells. Thus, studies related to its potential functional roles have traditionally focused on tumorigenesis. PD-Ialpha/ATX's catalytic activity, initially defined as nucleotide pyrophosphatase/phosphodiesterase, was soon recognized as being necessary for its tumor cell-motility-stimulating activity. However, only the discovery of PD-Ialpha/ATX's identity with lysophospholipase D, an extracellular enzyme that converts lysophosphatidylcholine into lysophosphatidic acid (LPA) and potentially sphingosylphosphoryl choline into sphingosine 1-phosphate (S1P), revealed the actual effectors responsible for PD-Ialpha/ATX's ascribed motogenic functions, i.e., its catalytic products. PD-Ialpha/ATX has also been detected during normal development in a number of tissues, in particular, the central nervous system (CNS), where expression levels are high. Similar to tumor cells, PD-Ialpha/ATX-expressing CNS cells secrete catalytically active PD-Ialpha/ATX into the extracellular environment. Thus, it appears reasonable to assume that PD-Ialpha/ATX's CNS-related functions are mediated via lysophospholipid, LPA and potentially S1P, signaling. However, recent studies identified PD-Ialpha/ATX as a matricellular protein involved in the modulation of oligodendrocyte-extracellular matrix interactions and oligodendrocyte remodeling. This property of PD-Ialpha/ATX was found to be independent of its catalytic activity and to be mediated by a novel functionally active domain. These findings, therefore, uncover PD-Ialpha/ATX, at least in the CNS, as a multifunctional protein able to induce complex signaling cascades via distinct structure-function domains. This Mini-Review describes PD-Ialpha/ATX's multifunctional roles in the CNS and discusses their potential contributions to CNS development and pathology.
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Affiliation(s)
- Jameel Dennis
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, Richmond, 23298, USA
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93
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Saini HS, Coelho RP, Goparaju SK, Jolly PS, Maceyka M, Spiegel S, Sato-Bigbee C. Novel role of sphingosine kinase 1 as a mediator of neurotrophin-3 action in oligodendrocyte progenitors. J Neurochem 2006; 95:1298-310. [PMID: 16313513 DOI: 10.1111/j.1471-4159.2005.03451.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We had found previously that neurotrophin-3 (NT-3) is a potent stimulator of cAMP-response element binding protein (CREB) phosphorylation in cultured oligodendrocyte progenitors. Here, we show that CREB phosphorylation in these cells is also highly stimulated by sphingosine-1-phosphate (S1P), a sphingolipid metabolite that is known to be a potent mediator of numerous biological processes. Moreover, CREB phosphorylation in response to NT-3 involves sphingosine kinase 1 (SphK1), the enzyme that synthesizes S1P. Immunocytochemistry and confocal microscopy indicated that NT-3 induces translocation of SphK1 from the cytoplasm to the plasma membrane of oligodendrocytes, a process accompanied by increased SphK1 activity in the membrane fraction where its substrate sphingosine resides. To examine the involvement of SphK1 in NT-3 function, SphK1 expression was down-regulated by treatment with SphK1 sequence-specific small interfering RNA. Remarkably, the capacity of NT-3 to protect oligodendrocyte progenitors from apoptotic cell death induced by growth factor deprivation was abolished by down-regulating the expression of SphK1, as assessed by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay. Altogether, these results suggest that SphK1 plays a crucial role in the stimulation of oligodendrocyte progenitor survival by NT-3, and demonstrate a functional link between NT-3 and S1P signaling, adding to the complexity of mechanisms that modulate neurotrophin function and oligodendrocyte development.
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Affiliation(s)
- Harsimran S Saini
- Department of Biochemistry, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298-0614, USA
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94
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Abstract
Lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) are potent biologically active lipid mediators that exert a wide range of cellular effects through specific G protein-coupled receptors. To date, four LPA receptors and five S1P receptors have been identified. These receptors are expressed in a large number of tissues and cell types, allowing for a wide variety of cellular responses to lysophospholipid signaling, including cell adhesion, cell motility, cytoskeletal changes, proliferation, angiogenesis, process retraction, and cell survival. In addition, recent studies in mice show that specific lysophospholipid receptors are required for proper cardiovascular, immune, respiratory, and reproductive system development and function. Lysophospholipid receptors may also have specific roles in cancer and other diseases. This review will cover identification and expression of the lysophospholipid receptors, as well as receptor signaling properties and function. Additionally, phenotypes of mice deficient for specific lysophospholipid receptors will be discussed to demonstrate how these animals have furthered our understanding of the role lysophospholipids play in normal biology and disease.
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Affiliation(s)
- R Rivera
- The Scripps Research Institute, Department of Molecular Biology, 10550 North Torrey Pines Road, ICND-118, CA 92037, USA
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95
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Jaillard C, Harrison S, Stankoff B, Aigrot MS, Calver AR, Duddy G, Walsh FS, Pangalos MN, Arimura N, Kaibuchi K, Zalc B, Lubetzki C. Edg8/S1P5: an oligodendroglial receptor with dual function on process retraction and cell survival. J Neurosci 2005; 25:1459-69. [PMID: 15703400 PMCID: PMC6726002 DOI: 10.1523/jneurosci.4645-04.2005] [Citation(s) in RCA: 259] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Endothelial differentiation gene (Edg) proteins are G-protein-coupled receptors activated by lysophospholipid mediators: sphingosine-1-phosphate (S1P) or lysophosphatidic acid. We show that in the CNS, expression of Edg8/S1P5, a high-affinity S1P receptor, is restricted to oligodendrocytes and expressed throughout development from the immature stages to the mature myelin-forming cell. S1P activation of Edg8/S1P5 on O4-positive pre-oligodendrocytes induced process retraction via a Rho kinase/collapsin response-mediated protein signaling pathway, whereas no retraction was elicited by S1P on these cells derived from Edg8/S1P5-deficient mice. Edg8/S1P5-mediated process retraction was restricted to immature cells and was no longer observed at later developmental stages. In contrast, S1P activation promoted the survival of mature oligodendrocytes but not of pre-oligodendrocytes. The S1P-induced survival of mature oligodendrocytes was mediated through a pertussis toxin-sensitive, Akt-dependent pathway. Our data demonstrate that Edg8/S1P5 activation on oligodendroglial cells modulates two distinct functional pathways mediating either process retraction or cell survival and that these effects depend on the developmental stage of the cell.
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MESH Headings
- Amino Acid Sequence
- Animals
- Ankyrins/analysis
- Brain/cytology
- Brain/growth & development
- Brain Chemistry
- Cell Differentiation
- Cell Lineage
- Cell Shape/drug effects
- Cell Surface Extensions/drug effects
- Cell Surface Extensions/physiology
- Cell Survival/drug effects
- Cells, Cultured/drug effects
- Cells, Cultured/metabolism
- Cells, Cultured/ultrastructure
- Crosses, Genetic
- Female
- GTP-Binding Protein alpha Subunit, Gi2
- GTP-Binding Protein alpha Subunits, Gi-Go/physiology
- Intercellular Signaling Peptides and Proteins
- Intracellular Signaling Peptides and Proteins
- Kv1.1 Potassium Channel
- Lysophospholipids/pharmacology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Molecular Sequence Data
- Nerve Tissue Proteins/deficiency
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Nerve Tissue Proteins/physiology
- Oligodendroglia/drug effects
- Oligodendroglia/metabolism
- Oligodendroglia/ultrastructure
- Phosphorylation
- Potassium Channels, Voltage-Gated/analysis
- Protein Processing, Post-Translational
- Protein Serine-Threonine Kinases/metabolism
- Protein Serine-Threonine Kinases/physiology
- Proto-Oncogene Proteins/physiology
- Proto-Oncogene Proteins c-akt
- RNA, Messenger/analysis
- RNA, Small Interfering/pharmacology
- Rats
- Rats, Wistar
- Receptors, Lysosphingolipid/deficiency
- Receptors, Lysosphingolipid/genetics
- Receptors, Lysosphingolipid/physiology
- Signal Transduction/drug effects
- Signal Transduction/physiology
- Sphingosine/analogs & derivatives
- Sphingosine/pharmacology
- rho-Associated Kinases
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Affiliation(s)
- C Jaillard
- Biologie des Interactions Neurones/Glie, Institut National de la Santé et de la Recherche Médicale and Université Pierre et Marie Curie, Unité Mixte de Recherche 711, Hôpital de la Salpêtrière, F-75651 Paris, France
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96
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Anelli V, Bassi R, Tettamanti G, Viani P, Riboni L. Extracellular release of newly synthesized sphingosine-1-phosphate by cerebellar granule cells and astrocytes. J Neurochem 2005; 92:1204-15. [PMID: 15715670 DOI: 10.1111/j.1471-4159.2004.02955.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Sphingosine-1-phosphate (S1P) is a potent biomediator that can act as either an intracellular or an intercellular messenger. In the nervous system it exerts a wide range of actions, and specific membrane receptors for it have been identified in various regions. However, the physiological origin of extracellular S1P in the nervous system is largely unknown. We investigated cerebellar granule cells at different stages of differentiation and astrocytes in primary cultures as possible origins of extracellular S1P. Although these cells show marked differences in S1P metabolism, we found that they can all release S1P and express mRNAs for S1P specific receptors. Extracellular S1P derives from the export of newly synthesized intracellular S1P, and not from the action of a released sphingosine kinase. S1P release is rapid, efficient, and can be regulated by exogenous stimuli. Phorbol ester treatment resulted in an increase in sphingosine kinase 1 activity in the membranes, accompanied by a significant increase in extracellular S1P. S1P release in cells from the cerebellum emerges as a regulated mechanism, possibly related to a specific pool of newly synthesized S1P. To our knowledge, this is the first evidence of the extracellular release of S1P by primary cells from the CNS, which supports a role of S1P as autocrine/paracrine physiological messenger in the cerebellum.
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Affiliation(s)
- Viviana Anelli
- Department of Medical Chemistry, Biochemistry and Biotechnology, University of Milan, Segrate, Milan, Italy
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97
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Abstract
Lysophosphatidic acid (LPA) elicits diverse cellular responses through cell surface LPA receptors in nervous system-derived cells and cell lines. The developing nervous system is one of the major loci for LPA receptor expression. Recent studies have also revealed that metabolic pathways of LPA are present in the nervous system. A growing body of literature suggests a crucial role for LPA in neuronal development processes, including neurogenesis, neuronal migration, neuritogenesis, and myelination.
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Affiliation(s)
- Nobuyuki Fukushima
- Department of Biochemistry, Hokkaido University Graduate School of Medicine, N15W7, Kita-ku, Sapporo 060-8638, Japan
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98
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Fox MA, Alexander JK, Afshari FS, Colello RJ, Fuss B. Phosphodiesterase-I alpha/autotaxin controls cytoskeletal organization and FAK phosphorylation during myelination. Mol Cell Neurosci 2005; 27:140-50. [PMID: 15485770 DOI: 10.1016/j.mcn.2004.06.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2004] [Revised: 05/12/2004] [Accepted: 06/08/2004] [Indexed: 11/26/2022] Open
Abstract
Myelination within the central nervous system (CNS) involves substantial morphogenesis of oligodendrocytes requiring plastic changes in oligodendrocyte-extracellular matrix (ECM) interactions, that is, adhesion. Our previous studies indicated that a regulator of such adhesive plasticity is oligodendrocyte-released phosphodiesterase-I alpha/autotaxin (PD-I alpha/ATX). We report here, that PD-I alpha/ATX's adhesion antagonism is mediated by a protein fragment different from the one that stimulates tumor cell motility. Furthermore, PD-I alpha/ATX's adhesion-antagonizing fragment causes a reorganized distribution of the focal adhesion components vinculin and paxillin and an integrin-dependent reduction in focal adhesion kinase (FAK) phosphorylation at tyrosine residue 925 (pFAK-925). In vivo, a similar reduction in pFAK-925 occurs at the onset of myelination when PD-I alpha/ATX expression is significantly upregulated. Most importantly, it can also be induced by the application of exogenous PD-I alpha/ATX. Our data, therefore, suggest that PD-I alpha/ATX participates in the regulation of myelination via a novel signaling pathway leading to changes in integrin-dependent focal adhesion assembly and consequently oligodendrocyte-ECM interactions.
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Affiliation(s)
- Michael A Fox
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA 23298, USA
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99
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Rao TS, Lariosa-Willingham KD, Lin FF, Yu N, Tham CS, Chun J, Webb M. Growth factor pre‐treatment differentially regulates phosphoinositide turnover downstream of lysophospholipid receptor and metabotropic glutamate receptors in cultured rat cerebrocortical astrocytes. Int J Dev Neurosci 2004; 22:131-5. [PMID: 15140466 DOI: 10.1016/j.ijdevneu.2004.03.005] [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] [Received: 02/06/2004] [Revised: 03/17/2004] [Accepted: 03/17/2004] [Indexed: 01/06/2023] Open
Abstract
Reactive gliosis is an aspect of neural plasticity and growth factor (GF) stimulation of astrocytes in vitro is widely regarded as a model system to study astrocyte plasticity. Astrocytes express receptors for several ligands including lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P), agonists for the G-protein-coupled lysophospholipid receptors (lpRs). Activation of lpRs by LPA or S1P leads to multiple pharmacological effects including the influx of calcium, phosphoinositide (PI) hydrolysis, phosphorylation of extracellular receptor regulated kinase (ERK), release of arachidonic acid, and induces mitogenesis. Treatment of astrocytes in vitro with a growth factor cocktail (containing epidermal growth factor [EGF], basic fibroblast growth factor [bFGF] and insulin) led to a marked attenuation of lpR-induced PI hydrolysis. In contrast, under identical conditions, GF treatment led to marked potentiation of PI hydrolysis downstream of activation of another abundantly expressed G-protein coupled receptor, mGluR5. Quantitative gene expression analysis of GF-treated or control astrocytes by TaqMan RT-PCR indicated that GF treatment did not change gene expression of lpa1 and s1p1, but increased gene expression of s1p5 which is expressed at very low levels in basal conditions. These results suggest that GF differentially affected PLC activation downstream of mGluR5 versus lpR activation and that the changes in mRNA levels of lpRs do not account for marked attenuation of agonist-induced phosphoinositide turnover.
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Affiliation(s)
- Tadimeti S Rao
- Merck Research Laboratories-San Diego, 3535 General Atomics Court, Bldg 1, San Diego, CA 92121, USA.
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Tham CS, Lin FF, Rao TS, Yu N, Webb M. Microglial activation state and lysophospholipid acid receptor expression. Int J Dev Neurosci 2003; 21:431-43. [PMID: 14659994 DOI: 10.1016/j.ijdevneu.2003.09.003] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
We used a simple commercial magnetic immunobead method for the preparation of acutely isolated microglial cells from postnatal days 1-3 rat brain. With the exception of a 15 min enzyme incubation, all stages are carried out at 4 degrees C, minimizing the opportunity for changes in gene expression during the isolation to be reflected in changes in accumulated mRNA. The composition of the isolated cells was compared with that of microglial cultures prepared by conventional tissue culture methods, and the purity of microglia was comparable between the two preparations. RT-PCR analysis of several genes related to inflammatory products indicated that the acutely prepared cells were in a less activated condition than the conventionally tissue cultured cells. We examined the pattern of expression of receptors for lysophosphatidic acid (lpa) and sphingosine-1-phosphate (S1P) using quantitative real-time PCR (TaqMan PCR) techniques. mRNA for LPA1, S1P1, S1P2, S1P3 and S1P5 was detected in these preparations, but the levels of the different receptor mRNAs varied according to the state of activation of the cells. mRNA for LPA3 was only detected significantly in cultured cell after lipopolysaccharide (LPS) stimulation, being almost absent in cultured microglia and undetectable in the acutely isolated preparations. The levels of mRNA of LPA1 and S1P receptors was reduced by overnight exposure to S1P, while the same treatment significantly up-regulated the level of LPA3 mRNA.
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MESH Headings
- Animals
- Animals, Newborn
- Astrocytes/metabolism
- Base Sequence
- Blotting, Northern
- CD11b Antigen/genetics
- CD11b Antigen/metabolism
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Cells, Cultured
- Cyclooxygenase 2
- Dose-Response Relationship, Drug
- Drug Interactions
- Enzyme Inhibitors/pharmacology
- Enzyme-Linked Immunosorbent Assay
- Fluorescent Antibody Technique/methods
- Gene Expression/drug effects
- Glial Fibrillary Acidic Protein/metabolism
- Imidazoles/pharmacology
- Indoles/metabolism
- Interleukin-6/genetics
- Interleukin-6/metabolism
- Isoenzymes/genetics
- Isoenzymes/metabolism
- Lectins/metabolism
- Lysophospholipids/pharmacology
- Microglia/metabolism
- Myelin Basic Protein/metabolism
- Nitric Oxide Synthase/genetics
- Nitric Oxide Synthase/metabolism
- Nitric Oxide Synthase Type II
- Oligodendroglia/metabolism
- Osteopontin
- Prostaglandin-Endoperoxide Synthases/genetics
- Prostaglandin-Endoperoxide Synthases/metabolism
- Pyridines/pharmacology
- RNA, Messenger/biosynthesis
- Rats
- Rats, Sprague-Dawley
- Receptors, G-Protein-Coupled/biosynthesis
- Receptors, G-Protein-Coupled/genetics
- Receptors, Lipoprotein/biosynthesis
- Receptors, Lipoprotein/drug effects
- Receptors, Lipoprotein/genetics
- Receptors, Lysophospholipid
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Sialoglycoproteins/genetics
- Sialoglycoproteins/metabolism
- Tumor Necrosis Factor-alpha/metabolism
- p38 Mitogen-Activated Protein Kinases
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Affiliation(s)
- Chui-Se Tham
- Molecular Neuroscience Laboratory, Merck Research Laboratories, 3535 General Atomics Court, San Diego, CA 92121, USA
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