551
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Desmaret S, Qian L, Vanloo B, Meerschaert K, Van Damme J, Grooten J, Vandekerckhove J, Prestwich GD, Gettemans J. Lysophosphatidic acid affinity chromatography reveals pyruvate kinase as a specific LPA-binding protein. Biol Chem 2006; 386:1137-47. [PMID: 16307479 DOI: 10.1515/bc.2005.130] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Lysophosphatidic acid is a pleiotropic lipid signaling molecule that evokes a broad array of cellular responses including proliferation, tumor cell invasion, neurite retraction, cytoskeletal rearrangements and smooth muscle contraction. Generally, lysophosphatidic acid triggers physiological responses through interaction with specific plasma membrane receptors called LPA 1-4. There is, however, increasing evidence in support of intracellular proteins that interact with LPA. We employed Affigel-immobilized LPA to isolate cytoplasmic proteins that interact with this lysophospholipid. Among the proteins retained by this affinity matrix, pyruvate kinase, clathrin heavy chain and heat shock protein 70 (Hsp70) were identified by mass spectrometry. Isothermal titration calorimetry showed that pyruvate kinase contains one binding site for LPA (Ka approx. 10(6) M(-1)). Furthermore, LPA dissociates enzymatically active pyruvate-kinase tetramers into less active dimers, and is maximally active at concentrations close to its critical micelle concentration. These effects were not mimicked by other lysophospholipids. Co-immunoprecipitation experiments showed that pyruvate kinase interacts with clathrin, and confocal imaging revealed co-localization between clathrin and pyruvate kinase in the perinuclear region of cells. Our data suggest that pyruvate kinase partly exists in complex with clathrin in subcellular membranous areas, and that locally increased LPA levels can trigger inactivation of the metabolic enzyme.
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Affiliation(s)
- Sophie Desmaret
- Department of Medical Protein Research, Flanders Interuniversity Institute for Biotechnology (VIB), Ghent University, Faculty of Medicine and Health Sciences, Albert Baertsoenkaai 3, B-9000 Ghent, Belgium
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552
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Yang TTC, Ung PMU, Rincón M, Chow CW. Role of the CCAAT/enhancer-binding protein NFATc2 transcription factor cascade in the induction of secretory phospholipase A2. J Biol Chem 2006; 281:11541-52. [PMID: 16500900 DOI: 10.1074/jbc.m511214200] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Inflammatory cytokines such as interleukin-1 and tumor necrosis factor-alpha modulate a transcription factor cascade in the liver to induce and sustain an acute and systemic defense against foreign entities. The transcription factors involved include NF-kappaB, STAT, and CCAAT/enhancer-binding protein (C/EBP). Whether the NFAT group of transcription factors (which was first characterized as playing an important role in cytokine gene expression in the adaptive response in immune cells) participates in the acute-phase response in hepatocytes is not known. Here, we have investigated whether NFAT is part of the transcription factor cascade in hepatocytes during inflammatory stress. We report that interleukin-1 or tumor necrosis factor-alpha increases expression of and activates NFATc2. C/EBP-mediated NFATc2 induction is temporally required for expression of type IIA secretory phospholipase A2. NFATc2 is also required for expression of phospholipase D1 and the calcium-binding protein S100A3. Thus, a C/EBP-NFATc2 transcription factor cascade provides an additional means to modulate the acute-phase response upon stimulation with inflammatory cytokines.
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Affiliation(s)
- Teddy T C Yang
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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553
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Gardell SE, Dubin AE, Chun J. Emerging medicinal roles for lysophospholipid signaling. Trends Mol Med 2006; 12:65-75. [PMID: 16406843 DOI: 10.1016/j.molmed.2005.12.001] [Citation(s) in RCA: 212] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2005] [Revised: 11/21/2005] [Accepted: 12/09/2005] [Indexed: 02/06/2023]
Abstract
The two lysophospholipids (LPs) lysophosphatidic acid and sphingosine 1-phosphate (S1P) regulate diverse biological processes. Over the past decade, it has become clear that medically relevant LP activities are mediated by specific G protein-coupled receptors, implicating them in the etiology of a growing number of disorders. A new class of LP agonists shows promise for drug therapy: the experimental drug FTY720 is phosphorylated in vivo to produce a potent S1P receptor agonist (FTY720-P) and is currently in Phase III clinical trials for kidney transplantation and Phase II for multiple sclerosis. Recent genetic and pharmacological studies on LP signaling in animal disease models have identified new areas in which interventions in LP signaling might provide novel therapeutic approaches for the treatment of human diseases.
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Affiliation(s)
- Shannon E Gardell
- Department of Molecular Biology, Helen L. Dorris Child and Adolescent Neuropsychiatric Disorder Institute, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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554
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Cho J, Mosher DF. Enhancement of thrombogenesis by plasma fibronectin cross-linked to fibrin and assembled in platelet thrombi. Blood 2006; 107:3555-63. [PMID: 16391013 PMCID: PMC1457097 DOI: 10.1182/blood-2005-10-4168] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To learn how plasma fibronectin stabilizes platelet-rich thrombi in injured mesenteric arterioles of mice, we studied the impact of plasma fibronectin on platelet thrombus formation ex vivo in a parallel flow chamber. Thrombi were greater on surfaces coated with fibrin cross-linked to fibronectin by activated factor XIII than on surfaces coated with fibrin lacking cross-linked fibronectin or with fibronectin alone. Platelet thrombi were even greater when plasma fibronectin was perfused with platelets, resulting in deposition of the perfused fibronectin in platelet thrombi. The effect of perfused fibronectin on thrombogenesis was lost if fibronectin deposition was blocked by coperfusion with the N-terminal 70-kDa fragment of fibronectin or a peptide based on the functional upstream domain of protein F1 of Streptococcus pyogenes. Increases in thrombus formation were dependent on a platelet activator such as lysophosphatidic acid, amount of fibronectin cross-linked to fibrin, and concentration of fibronectin in the perfusate. The dependency of fibronectin concentration extended into the range of fibronectin concentrations associated with increased risk of coronary artery disease. At such concentrations, the 2 mechanisms for insolubilization of plasma fibronectin-cross-linking to fibrin and assembly by adherent and aggregating platelets-synergize to result in many-fold enhancement of platelet thrombus formation.
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Affiliation(s)
- Jaehyung Cho
- Department of Medicine, University of Wisconsin-Madison, 4285 Medical Sciences Center, 1300 University Ave, Madison, 53706, USA
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555
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Kobayashi N, Nishi T, Hirata T, Kihara A, Sano T, Igarashi Y, Yamaguchi A. Sphingosine 1-phosphate is released from the cytosol of rat platelets in a carrier-mediated manner. J Lipid Res 2005; 47:614-21. [PMID: 16371645 DOI: 10.1194/jlr.m500468-jlr200] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Sphingosine 1-phosphate (S1P) is accumulated in platelets and released on stimulation by thrombin or Ca(2+). Thrombin-stimulated S1P release was inhibited by staurosporin, whereas Ca(2+)-stimulated release was not. When the platelet plasma membrane was permeabilized with streptolysin O (SLO), S1P leaked out with cytosol markers, whereas granular markers remained in the platelets. The SLO-induced S1P leakage required BSA, probably for solubilization of S1P in the medium. These results indicate that S1P is localized in the inner leaflet of the plasma membrane and that its release is a carrier-mediated process. We also used alpha-toxin (ATX), which makes smaller pores in the plasma membrane than SLO and depletes cytosolic ATP without BSA-dependent S1P leakage. The addition of ATP drove S1P release from ATX platelets. The ATP-driven S1P release from ATX platelets was greatly enhanced by thrombin. An ATP binding cassette transporter inhibitor, glyburide, prevents ATP- and thrombin-induced S1P release from platelets. Ca(2+) also stimulated S1P release from ATX platelets without ATP, whereas the Ca(2+)-induced release was not inhibited by glyburide. Our results indicate that two independent S1P release systems might exist in the platelet plasma membrane, an ATP-dependent system stimulated by thrombin and an ATP-independent system stimulated by Ca(2+).
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Affiliation(s)
- Nobuyoshi Kobayashi
- Department of Cell Membrane Biology, Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki-shi, Osaka 567-0047, Japan
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556
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Flemming PK, Dedman AM, Xu SZ, Li J, Zeng F, Naylor J, Benham CD, Bateson AN, Muraki K, Beech DJ. Sensing of lysophospholipids by TRPC5 calcium channel. J Biol Chem 2005; 281:4977-82. [PMID: 16368680 DOI: 10.1074/jbc.m510301200] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
TRPC calcium channels are emerging as a ubiquitous feature of vertebrate cells, but understanding of them is hampered by limited knowledge of the mechanisms of activation and identity of endogenous regulators. We have revealed that one of the TRPC channels, TRPC5, is strongly activated by common endogenous lysophospholipids including lysophosphatidylcholine (LPC) but, by contrast, not arachidonic acid. Although TRPC5 was stimulated by agonists at G-protein-coupled receptors, TRPC5 activation by LPC occurred downstream and independently of G-protein signaling. The effect was not due to the generation of reactive oxygen species or because of a detergent effect of LPC. LPC activated TRPC5 when applied to excised membrane patches and thus has a relatively direct action on the channel structure, either because of a phospholipid binding site on the channel or because of sensitivity of the channel to perturbation of the bilayer by certain lipids. Activation showed dependence on side-chain length and the chemical head-group. The data revealed a previously unrecognized lysophospholipid-sensing capability of TRPC5 that confers the property of a lipid ionotropic receptor.
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Affiliation(s)
- Philippa K Flemming
- Institute of Membrane and Systems Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
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557
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Kooijman EE, Carter KM, van Laar EG, Chupin V, Burger KNJ, de Kruijff B. What Makes the Bioactive Lipids Phosphatidic Acid and Lysophosphatidic Acid So Special? Biochemistry 2005; 44:17007-15. [PMID: 16363814 DOI: 10.1021/bi0518794] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phosphatidic acid and lysophosphatidic acid are minor but important anionic bioactive lipids involved in a number of key cellular processes, yet these molecules have a simple phosphate headgroup. To find out what is so special about these lipids, we determined the ionization behavior of phosphatidic acid (PA) and lysophosphatidic acid (LPA) in extended (flat) mixed lipid bilayers using magic angle spinning 31P NMR. Our data show two surprising results. First, despite identical phosphomonoester headgroups, LPA carries more negative charge than PA when present in a phosphatidylcholine bilayer. Dehydroxy-LPA [1-oleoyl-3-(phosphoryl)propanediol] behaves in a manner identical to that of PA, indicating that the difference in negative charge between LPA and PA is caused by the hydroxyl on the glycerol backbone of LPA and its interaction with the phosphomonoester headgroup. Second, deprotonation of phosphatidic acid and lysophosphatidic acid was found to be strongly stimulated by the inclusion of phosphatidylethanolamine in the bilayer, indicating that lipid headgroup charge depends on local lipid composition and will vary between the different subcellular locations of (L)PA. Our findings can be understood in terms of a hydrogen bond formed within the phosphomonoester headgroup of (L)PA and its destabilization by competing intra- or intermolecular hydrogen bonds. We propose that this hydrogen bonding property of (L)PA is involved in the various cellular functions of these lipids.
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Affiliation(s)
- Edgar E Kooijman
- Department of Biochemistry of Membranes, Bijvoet Center, Institute of Biomembranes, Utrecht University, Utrecht, The Netherlands.
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558
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Kim MY, Liang GH, Kim JA, Kim YJ, Oh S, Suh SH. Sphingosine-1-phosphate activates BKCa channels independently of G protein-coupled receptor in human endothelial cells. Am J Physiol Cell Physiol 2005; 290:C1000-8. [PMID: 16267108 DOI: 10.1152/ajpcell.00353.2005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of sphingosine-1-phosphate (S1P) on large-conductance Ca(2+)-activated K(+) (BK(Ca)) channels was examined in primary cultured human umbilical vein endothelial cells by measuring intracellular Ca(2+) concentration ([Ca(2+)](i)), whole cell membrane currents, and single-channel activity. In nystatin-perforated current-clamped cells, S1P hyperpolarized the membrane and simultaneously increased [Ca(2+)](i). [Ca(2+)](i) and membrane potentials were strongly correlated. In whole cell clamped cells, BK(Ca) currents were activated by increasing [Ca(2+)](i) via cell dialysis with pipette solution, and the activated BK(Ca) currents were further enhanced by S1P. When [Ca(2+)](i) was buffered at 1 microM, the S1P concentration required to evoke half-maximal activation was 403 +/- 13 nM. In inside-out patches, when S1P was included in the bath solution, S1P enhanced BK(Ca) channel activity in a reversible manner and shifted the relationship between Ca(2+) concentration in the bath solution and the mean open probability to the left. In whole cell clamped cells or inside-out patches loaded with guanosine 5'-O-(2-thiodiphosphate) (GDPbetaS; 1 mM) using a patch pipette, GDPbetaS application or pretreatment of cells with pertussis toxin (100 ng/ml) for 15 h did not affect S1P-induced BK(Ca) current and channel activation. These results suggest that S1P enhances BK(Ca) channel activity by increasing Ca(2+) sensitivity. This channel activation hyperpolarizes the membrane and thereby increases Ca(2+) influx through Ca(2+) entry channels. Inasmuch as S1P activates BK(Ca) channels via a mechanism independent of G protein-coupled receptors, S1P may be a component of the intracellular second messenger that is involved in Ca(2+) mobilization in human endothelial cells.
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Affiliation(s)
- Moon Young Kim
- Department of Physiology, College of Medicine, Ewha Woman's Univ., 911-1 Mok-6-dong, Yang Chun-gu, Seoul, Republic of Korea, 158-710
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559
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Park KA, Vasko MR. Lipid mediators of sensitivity in sensory neurons. Trends Pharmacol Sci 2005; 26:571-7. [PMID: 16185776 DOI: 10.1016/j.tips.2005.09.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2005] [Revised: 08/10/2005] [Accepted: 09/12/2005] [Indexed: 01/23/2023]
Abstract
Growing evidence implicates an increasing number of novel lipids, including eicosanoids, diacylglycerols, lysophosphatidic acids and ceramides, in augmenting the sensitivity of sensory neurons and enhancing pain perception. Many of these lipids are second messengers in signaling pathways that are associated with increasing the sensitivity of sensory neurons, whereas others are putative inflammatory mediators that activate either surface receptors or ion channels in these neurons. Based on the studies we review, it is clear that lipid-derived inflammatory mediators are a novel group of targets for therapeutics to treat inflammation and chronic pain states. However, much work remains to define the roles of these lipids in inflammation and the cellular mechanisms by which they alter the sensitivity of sensory neurons.
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Affiliation(s)
- Kellie A Park
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202-5126, USA
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560
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Cechin SR, Dunkley PR, Rodnight R. Signal transduction mechanisms involved in the proliferation of C6 glioma cells induced by lysophosphatidic acid. Neurochem Res 2005; 30:603-11. [PMID: 16176063 DOI: 10.1007/s11064-005-2747-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
We studied pathways involved in the proliferation of rat C6 glioma cells induced by lysophosphatidic acid (LPA), a phospholipid with diverse biological functions. LPA induced a dose-responsive proliferation of C6 cells after 48 h. Proliferation was blocked by inhibitors of the sodium/proton exchanger type 1 (NHE1), Rho-associated kinase, the phosphatidylinositol 3-kinase/Akt pathway (PI3K/Akt), protein kinase C (PKC) and extracellular signal regulated kinase kinase (MEK). Phospho-specific antibodies were used to investigate the pathways involved. LPA induced transient (10 min) phosphorylations of ERK 1/2, Akt and the transcription factor CREB. The LPA-induced phosphorylation of ERK 1/2 and CREB was blocked by inhibition of PI3K, PKC and MEK, but that of Akt was only inhibited by wortmannin, the PI3K inhibitor. Inhibition of Rho kinase or NHE1 did not reduce the LPA-induced phosphorylation of ERK, Akt or CREB. The results were compared with the effects of LPA on transduction pathways in other cell types.
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Affiliation(s)
- Sirlene R Cechin
- School of Biomedical Sciences and the Hunter Medical Research Institute, University of Newcastle, 2308, Callaghan, NSW, Australia
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561
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Sigal Y, McDERMOTT M, Morris A. Integral membrane lipid phosphatases/phosphotransferases: common structure and diverse functions. Biochem J 2005; 387:281-93. [PMID: 15801912 PMCID: PMC1134956 DOI: 10.1042/bj20041771] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Phospholipids and sphingolipids play critical roles in signal transduction, intracellular membrane trafficking, and control of cell growth and survival. We discuss recent progress in the identification and characterization of a family of integral membrane proteins with central roles in bioactive lipid metabolism and signalling. These five groups of homologous proteins, which we collectively term LPTs (lipid phosphatases/phosphotransferases), are characterized by a core domain containing six transmembrane-spanning alpha-helices connected by extramembrane loops, two of which interact to form the catalytic site. LPT family members are localized to all major membrane compartments of the cell. The transmembrane topology of these proteins places their active site facing the lumen of endomembrane compartments or the extracellular face of the plasma membrane. Sequence conservation between the active site of the LPPs (lipid phosphate phosphatases), SPPs (sphingosine phosphate phosphatases) and the recently identified SMSs (sphingomyelin synthases) with vanadium-dependent fungal oxidases provides a framework for understanding their common catalytic mechanism. LPPs hydrolyse LPA (lysophosphatidic acid), S1P (sphingosine 1-phosphate) and structurally-related substrates. Although LPPs can dephosphorylate intracellularly generated substrates to control intracellular lipid metabolism and signalling, their best understood function is to regulate cell surface receptor-mediated signalling by LPA and S1P by inactivating these lipids at the plasma membrane or in the extracellular space. SPPs are intracellularly localized S1P-selective phosphatases, with key roles in the pathways of sphingolipid metabolism linked to control of cell growth and survival. The SMS enzymes catalyse the interconversion of phosphatidylcholine and ceramide with sphingomyelin and diacylglycerol, suggesting a pivotal role in both housekeeping lipid synthesis and regulation of bioactive lipid mediators. The remaining members of the LPT family, the LPR/PRGs (lipid phosphatase-related proteins/plasticity-related genes) and CSS2s (type 2 candidate sphingomyelin synthases), are presently much less well studied. These two groups include proteins that lack critical amino acids within the catalytic site, and could therefore not use the conserved LPT reaction mechanism to catalyse lipid phosphatase or phosphotransferase reactions. In this review, we discuss recent ideas about their possible biological activities and functions, which appear to involve regulation of cellular morphology and, possibly, lipid metabolism and signalling in the nuclear envelope.
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Affiliation(s)
- Yury J. Sigal
- Department of Cell and Developmental Biology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7090, U.S.A
| | - Mark I. McDERMOTT
- Department of Cell and Developmental Biology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7090, U.S.A
| | - Andrew J. Morris
- Department of Cell and Developmental Biology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7090, U.S.A
- To whom correspondence should be addressed (email )
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562
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Abstract
Heterotrimeric G proteins are key players in transmembrane signaling by coupling a huge variety of receptors to channel proteins, enzymes, and other effector molecules. Multiple subforms of G proteins together with receptors, effectors, and various regulatory proteins represent the components of a highly versatile signal transduction system. G protein-mediated signaling is employed by virtually all cells in the mammalian organism and is centrally involved in diverse physiological functions such as perception of sensory information, modulation of synaptic transmission, hormone release and actions, regulation of cell contraction and migration, or cell growth and differentiation. In this review, some of the functions of heterotrimeric G proteins in defined cells and tissues are described.
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Affiliation(s)
- Nina Wettschureck
- Institute of Pharmacology, University of Heidelberg, Im Neuenheimer Feld 366, D-69120 Heidelberg, Germany
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563
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Czeloth N, Bernhardt G, Hofmann F, Genth H, Förster R. Sphingosine-1-phosphate mediates migration of mature dendritic cells. THE JOURNAL OF IMMUNOLOGY 2005; 175:2960-7. [PMID: 16116182 DOI: 10.4049/jimmunol.175.5.2960] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Sphingosine-1-phosphate (S1P) represents a potent modulator of diverse cellular activities, including lymphocyte trafficking and maintenance of lymphocyte homeostasis. The five known receptors for S1P (S1P(1-5)) belong to the family of G protein-coupled receptors. Upon binding S1P, they act downstream via heterotrimeric G proteins on members of the small GTPase family (Cdc42/Rac/Rho), evoking a S1P receptor-dependent activation pattern of Cdc42, Rac, and Rho, respectively. This, in turn, triggers cytoskeletal rearrangements determining cellular morphology and movement. In this study we investigated the effects of S1P on murine dendritic cells (DC). Mature DC, but not immature in vitro differentiated DC, were found to migrate to S1P, a phenomenon that correlated to the up-regulation of S1P1 and S1P3 in maturing DC. The same pattern of S1P receptor regulation could be observed in vivo on skin DC after their activation and migration into the lymph node. The migration-inducing effect of S1P could be severely hampered by application of the S1P analogon FTY720 in vitro and in vivo. A similar, yet more pronounced, block was observed upon preventing Cdc42/Rac and/or Rho activation by specific inhibitors. These results suggest that S1P-mediated signaling plays a pivotal role in the life cycle of DC.
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Affiliation(s)
- Niklas Czeloth
- Institute of Immunology, Hannover Medical School, Germany
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564
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Nofer JR, Assmann G. Atheroprotective Effects of High-Density Lipoprotein-Associated Lysosphingolipids. Trends Cardiovasc Med 2005; 15:265-71. [PMID: 16226682 DOI: 10.1016/j.tcm.2005.08.005] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2005] [Revised: 08/12/2005] [Accepted: 08/18/2005] [Indexed: 01/08/2023]
Abstract
Numerous epidemiological studies document an inverse relationship between plasma high-density lipoprotein (HDL) levels and the extent of atherosclerotic disease. The atheroprotective effects of HDL are more and more often seen in conjunction with the ability of HDL to restrict proinflammatory processes and thereby to carry out cytoprotection and organoprotection. Lysosphingolipids such as sphingosine 1 phosphate, sphingosylphosphorylcholine, and lysosulfatide are biologically active compounds that have recently been found to be associated with HDL particles. An increasing body of evidence suggests that several anti-inflammatory effects exerted by HDL can be attributed to the presence of lysosphingolipids in this lipoprotein fraction. In this review, we discuss the latest developments concerning the potential atheroprotective role of HDL-associated lysosphingolipids.
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Affiliation(s)
- Jerzy-Roch Nofer
- Institut für Klinische Chemie und Laboratoriumsmedizin, Universitätsklinikum Münster, Albert Schweitzer Strasse 33, D-48129 Münster, Germany.
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565
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Fujiwara Y, Sardar V, Tokumura A, Baker D, Murakami-Murofushi K, Parrill A, Tigyi G. Identification of Residues Responsible for Ligand Recognition and Regioisomeric Selectivity of Lysophosphatidic Acid Receptors Expressed in Mammalian Cells. J Biol Chem 2005; 280:35038-50. [PMID: 16115890 DOI: 10.1074/jbc.m504351200] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The endothelial differentiation gene family encodes three highly homologous G protein-coupled receptors for lysophosphatidic acid (LPA). Based on baculoviral overexpression studies, differences have been proposed in the structure-activity relationship (SAR) of these receptors. We have compared the SAR of the individual receptors either overexpressed transiently at high or at lower levels following stable transfection in LPA-nonresponsive RH7777 cells. The SAR in transfected RH7777 cells was markedly different from that described in insect cells. The LPA(3) receptor has been proposed to be selectively activated by unsaturated LPA species and shows a strong preference for sn-2 versus the sn-1 acyl-LPA regioisomer. Because of the short half-life of sn-2 LPA due to acyl migration under some conditions, we have synthesized acyl migration-resistant analogs using an acetyl group in place of the free hydroxyl group in order to evaluate LPA receptor SAR. Only LPA(1) and LPA(2) showed regioisomeric preference and only for the 18:2 fatty acyl-stabilized LPA sn-1 regioisomer. To identify residues involved in ligand recognition of LPA(3), we developed and validated computational models of LPA(3) complexes with the analogs studied. The models revealed that Arg-3.28 and Gln-3.29 conserved within the LPA-selective endothelial differentiation gene receptors and the more variable Lys-7.35 and Arg-5.38 of LPA(3) form critical interactions with the polar headgroup of LPA. The models identified Leu-2.60 and Val-7.39 of LPA(3) underlying the regioisomer-selective interaction with the acetyl group of the stabilized regioisomers. Mutation of Leu-2.60 to alanine selectively increased the EC(50) of the sn-2 acetyl-LPA regioisomers, whereas alanine replacement of Val-7.39 profoundly affected both regioisomers.
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Affiliation(s)
- Yuko Fujiwara
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee 38152, USA
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566
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Rosen H, Goetzl EJ. Sphingosine 1-phosphate and its receptors: an autocrine and paracrine network. Nat Rev Immunol 2005; 5:560-70. [PMID: 15999095 DOI: 10.1038/nri1650] [Citation(s) in RCA: 565] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Sphingosine 1-phosphate (S1P) is a biologically active lysophospholipid that transmits signals through a family of G-protein-coupled receptors to control cellular differentiation and survival, as well as the vital functions of several types of immune cell. In this Review article, we discuss recent results that indicate that S1P and its receptors are required for the emigration of thymocytes from the thymus, the trafficking of lymphocytes in secondary lymphoid organs and the migration of B cells into splenic follicles. In an autocrine manner, through interactions with different G-protein-coupled receptors, S1P also enhances optimal mast-cell migration and release of pro-inflammatory mediators in allergic reactions. S1P-S1P-receptor regulatory systems might therefore be novel targets for the therapy of diverse immunological diseases.
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Affiliation(s)
- Hugh Rosen
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037, USA
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567
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Kimura T, Tomura H, Mogi C, Kuwabara A, Ishiwara M, Shibasawa K, Sato K, Ohwada S, Im DS, Kurose H, Ishizuka T, Murakami M, Okajima F. Sphingosine 1-phosphate receptors mediate stimulatory and inhibitory signalings for expression of adhesion molecules in endothelial cells. Cell Signal 2005; 18:841-50. [PMID: 16111867 DOI: 10.1016/j.cellsig.2005.07.011] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2005] [Revised: 07/14/2005] [Accepted: 07/18/2005] [Indexed: 11/30/2022]
Abstract
Sphingosine 1-phosphate (S1P) stimulates expression of vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 in human umbilical vein endothelial cells. S1P-induced actions were associated with nuclear factor kappa-B activation and inhibited by pertussis toxin as well as by antisense oligonucleotides specific to S1P receptors, especially, S1P(3). S1P also stimulated endothelial nitric oxide synthase (eNOS) and its activation was markedly inhibited by the antisense oligonucleotide for the S1P(1) receptor rather than that for the S1P(3) receptor. The dose-response curve of S1P to stimulate adhesion molecule expression was shifted to the left in the presence of the phosphatidylinositol 3-kinase inhibitor wortmannin and the NOS inhibitor Nomega-nitro-l-arginine methyl ester. NO donor S-nitroso-N-acetylpenicillamine inhibited S1P-induced adhesion molecule expression. Moreover, tumor necrosis factor-alpha-induced adhesion molecule expression was markedly inhibited by S1P in a manner sensitive to inhibitors for PI3-K and NOS. These results suggest that S1P receptors are coupled to both stimulatory and inhibitory pathways for adhesion molecule expression. The stimulatory pathway involves nuclear factor kappa-B and inhibitory one does phosphatidylinositol 3-kinase and NOS.
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Affiliation(s)
- Takao Kimura
- Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi 371-8512, Japan
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568
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Howlett AC. A short guide to the nomenclature of seven-transmembrane spanning receptors for lipid mediators. Life Sci 2005; 77:1522-30. [PMID: 15953619 DOI: 10.1016/j.lfs.2005.05.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The International Union of Pharmacology (IUPHAR) has established a Nomenclature Committee comprised of sub-committees of experts to evaluate types and subtypes of receptors and ion channels in an effort to establish universally accepted nomenclature [Vanhoutte, P.M., Barnard, E.A., Cosmides, G.J., Humphrey, P.P., Spedding, M., Godfraind, T., 1994. International Union of Pharmacology Committee on Receptor Nomenclature and Drug Classification. Pharmacological Reviews 46, 111-116]. This overview cites the reports of the IUPHAR subcommittees and other prominent review articles in an effort to compile receptors for lipid mediators that bind to and evoke their pharmacological responses via seven-transmembrane spanning, G-protein-coupled receptors.
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Affiliation(s)
- Allyn C Howlett
- Neuroscience of Drug Abuse Research Program, Julius L. Chambers Biomedical Biotechnology Research Institute, North Carolina Central University, 700 George Street, Durham, NC 27707, USA.
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569
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Wu WT, Chen CN, Lin CI, Chen JH, Lee H. Lysophospholipids enhance matrix metalloproteinase-2 expression in human endothelial cells. Endocrinology 2005; 146:3387-400. [PMID: 15878967 DOI: 10.1210/en.2004-1654] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) are both low-molecular-weight lysophospholipids, which promote cell proliferation, migration, and invasion via interaction with a family of specific G protein-coupled receptors. Matrix metalloproteinases (MMPs) are zinc-dependent proteolytic enzymes, which are involved in degradation of the extracellular matrix and play critical roles in endothelial cell migration and matrix remodeling during angiogenesis. Among these MMPs, MMP-2 is known to trigger cell migration. In our present study, we examined the effects of LPA and S1P on MMP-2 expression in human endothelial cells. We showed that LPA and S1P enhanced MMP-2 expression in mRNA, protein levels, and also enzymatic activity of cells of the EAhy926 human endothelial cell line. The enhancement effects occurred in concentration- and time-dependent manners. Results from real-time PCR, Western blots, and substrate gels indicated that these enhancement effects were mediated through MAPK kinase/ERK-, nuclear factor-kappaB-, and calcium influx-dependent pathways. Furthermore, we show that endothelial cell invasion of the gel was enhanced by lysophospholipids, and the induction could be prevented by an MMP inhibitor, GM6001. These observations suggest that LPA and S1P may play important roles in endothelial cell invasion by regulating the expression of MMP-2.
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Affiliation(s)
- Wen Ting Wu
- Institute of Zoology, National Taiwan University, Taipei, Taiwan 10617, Republic of China
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570
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Johnstone ED, Chan G, Sibley CP, Davidge ST, Lowen B, Guilbert LJ. Sphingosine-1-phosphate inhibition of placental trophoblast differentiation through a G(i)-coupled receptor response. J Lipid Res 2005; 46:1833-9. [PMID: 15995175 DOI: 10.1194/jlr.m500095-jlr200] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The failure of placental trophoblasts to differentiate properly is thought to play an important role in the cause of pregnancy disorders such as preeclampsia. We looked at the effects of the bioactive lipid sphingosine-1-phosphate (S1P) on the differentiation of primary human cytotrophoblasts (CTs) into syncytiotrophoblasts (STs) in culture. We found that S1P inhibited CT differentiation measured by human chorionic gonadotropin (hCG) secretion and the expression of placental alkaline phosphatase but had no effect on their fusion into multinucleated syncytialized cells. G-protein-linked S1P receptors 1, 2, and 3 were found in CTs by reverse transcriptase-polymerase chain reaction, and receptor 1 was found by Western blot analysis. Disruption of G(i) signaling with pertussis toxin reversed the inhibitory effects of S1P. S1P reduced intracellular cAMP, and the addition of 8-bromo-cAMP reversed S1P inhibition of hCG secretion. Therefore, we suggest that S1P inhibits the differentiation of CTs into STs through G(i)-coupled S1P receptor interaction(s), leading to the inhibition of adenylate cyclase and reduced production of intracellular cAMP. This is the first reported effect of S1P on placental trophoblast function.
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Affiliation(s)
- Edward D Johnstone
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
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571
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Abstract
Secondary lymphoid organs serve as hubs for the adaptive immune system, bringing together antigen, antigen-presenting cells, and lymphocytes. Two families of G protein-coupled receptors play essential roles in lymphocyte migration through these organs: chemokine receptors and sphingosine-1-phosphate (S1P) receptors. Chemokines expressed by lymphoid stromal cells guide lymphocyte and dendritic cell movements during antigen surveillance and the initiation of adaptive immune responses. S1P receptor-1 is required for lymphocyte egress from thymus and secondary lymphoid organs and is downregulated by the immunosuppressive drug FTY720. Here, we review the steps associated with the initiation of adaptive immune responses in secondary lymphoid organs, highlighting the roles of chemokines and S1P.
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Affiliation(s)
- Jason G Cyster
- Howard Hughes Medical Institute and Department of Microbiology and Immunology, University of California, San Francisco, California 94143-0414, USA.
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572
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Geho DH, Bandle RW, Clair T, Liotta LA. Physiological mechanisms of tumor-cell invasion and migration. Physiology (Bethesda) 2005; 20:194-200. [PMID: 15888576 DOI: 10.1152/physiol.00009.2005] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Recent advances in understanding the complex biology of the microenvironment that underlies tumor invasion and migration have revealed novel and promising therapeutic targets. Pharmacological blockade of intra- and extracellular signaling events that regulate migration and survival of multiple cell types may disrupt the host-tumor conspiracy that allows escape from normal developmental regulation.
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Affiliation(s)
- David H Geho
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
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573
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Gon Y, Wood MR, Kiosses WB, Jo E, Sanna MG, Chun J, Rosen H. S1P3 receptor-induced reorganization of epithelial tight junctions compromises lung barrier integrity and is potentiated by TNF. Proc Natl Acad Sci U S A 2005; 102:9270-5. [PMID: 15968000 PMCID: PMC1166603 DOI: 10.1073/pnas.0501997102] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pulmonary pathologies including adult respiratory distress syndrome are characterized by disruption of pulmonary integrity and edema compromising respiratory function. Sphingosine 1-phosphate (S1P) is a lipid mediator synthesized and/or stored in mast cells, platelets, and epithelial cells, with production up-regulated by the proinflammatory cytokines IL-1 and TNF. S1P administration via the airways but not via the vasculature induces lung leakage. Using receptor-null mice, we show that S1P, acting on S1P3 receptor expressed on both type I and type II alveolar epithelial cells but not vascular endothelium, induces pulmonary edema by acute tight junction opening. WT but not S1P3-null mice showed disruption of pulmonary epithelial tight junctions and the appearance of paracellular gaps between epithelial cells by electron microscopy within 1 h of airways exposure to S1P. We further show by fluorescence microscopy that S1P induced rapid loss of ZO-1 reactivity, an essential component of the cytoplasmic plaque associated with tight junctions, as well as of the tetraspannin Claudin-18, an integral membrane organizer of tight junctions. S1P shows synergistic activity with the proinflammatory cytokine TNF, showing both pulmonary edema and mortality at subthreshold S1P doses. Specifically, preexposure of mice to subthreshold doses of TNF, which alone induced no lung edema, exacerbated S1P-induced edema and impaired survival. S1P, acting through S1P3, regulates epithelial integrity and acts additively with TNF in compromising respiratory barrier function. Because S1P3-null mice are resistant to S1P-induced pulmonary leakage, either alone or in the presence of TNF, S1P3 antagonism may be useful in protecting epithelial integrity in pulmonary disease.
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MESH Headings
- Animals
- Cell Membrane/metabolism
- Cell Nucleus/metabolism
- Chromatography, Liquid
- Claudins
- Cytoplasm/metabolism
- Endothelium, Vascular/metabolism
- Epithelial Cells/metabolism
- Epithelium/metabolism
- Guanosine Triphosphate/metabolism
- Homozygote
- Inflammation
- Interleukin-1/metabolism
- Ligands
- Lung/metabolism
- Lung Diseases/metabolism
- Membrane Proteins/metabolism
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Microscopy, Electron
- Microscopy, Fluorescence
- Models, Biological
- Permeability
- Protein Binding
- RNA, Messenger/metabolism
- Receptors, Lysosphingolipid/metabolism
- Receptors, Lysosphingolipid/physiology
- Tight Junctions/metabolism
- Time Factors
- Tumor Necrosis Factor-alpha/metabolism
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Affiliation(s)
- Yasuhiro Gon
- Department of Immunology, Core Microscopy Facility, Helen L. Dorris Child and Adolescent Neuro-Psychiatric Disorder Institute, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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574
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Ye X, Hama K, Contos JJ, Anliker B, Inoue A, Skinner MK, Suzuki H, Amano T, Kennedy G, Arai H, Aoki J, Chun J. LPA3-mediated lysophosphatidic acid signalling in embryo implantation and spacing. Nature 2005; 435:104-8. [PMID: 15875025 PMCID: PMC1369590 DOI: 10.1038/nature03505] [Citation(s) in RCA: 396] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2005] [Accepted: 02/28/2005] [Indexed: 01/24/2023]
Abstract
Every successful pregnancy requires proper embryo implantation. Low implantation rate is a major problem during infertility treatments using assisted reproductive technologies. Here we report a newly discovered molecular influence on implantation through the lysophosphatidic acid (LPA) receptor LPA3 (refs 2-4). Targeted deletion of LPA3 in mice resulted in significantly reduced litter size, which could be attributed to delayed implantation and altered embryo spacing. These two events led to delayed embryonic development, hypertrophic placentas shared by multiple embryos and embryonic death. An enzyme demonstrated to influence implantation, cyclooxygenase 2 (COX2) (ref. 5), was downregulated in LPA3-deficient uteri during pre-implantation. Downregulation of COX2 led to reduced levels of prostaglandins E2 and I2 (PGE2 and PGI2), which are critical for implantation. Exogenous administration of PGE2 or carbaprostacyclin (a stable analogue of PGI2) into LPA3-deficient female mice rescued delayed implantation but did not rescue defects in embryo spacing. These data identify LPA3 receptor-mediated signalling as having an influence on implantation, and further indicate linkage between LPA signalling and prostaglandin biosynthesis.
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Affiliation(s)
- Xiaoqin Ye
- Department of Molecular Biology, Helen L. Dorris Child and Adolescent Neuro-psychiatric Disorder Institute, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Kotaro Hama
- Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - James J.A. Contos
- Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109-1024
| | - Brigitte Anliker
- Department of Molecular Biology, Helen L. Dorris Child and Adolescent Neuro-psychiatric Disorder Institute, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Aska Inoue
- Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Michael K. Skinner
- Center for Reproductive Biology, School of Molecular Bioscience, Washington State University, Pullman, WA 99164-4231, USA
| | - Hiroshi Suzuki
- Developmental and Medical Technology (Sankyo), Department of Medicine, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Tomokazu Amano
- Developmental and Medical Technology (Sankyo), Department of Medicine, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Grace Kennedy
- Department of Molecular Biology, Helen L. Dorris Child and Adolescent Neuro-psychiatric Disorder Institute, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Hiroyuki Arai
- Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Junken Aoki
- Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Jerold Chun
- Department of Molecular Biology, Helen L. Dorris Child and Adolescent Neuro-psychiatric Disorder Institute, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
- Correspondence and requests for materials should be addressed to J. Chun (e-mail:)
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575
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576
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Tölle M, Levkau B, Keul P, Brinkmann V, Giebing G, Schönfelder G, Schäfers M, von Wnuck Lipinski K, Jankowski J, Jankowski V, Chun J, Zidek W, Van der Giet M. Immunomodulator FTY720 Induces eNOS-dependent arterial vasodilatation via the lysophospholipid receptor S1P3. Circ Res 2005; 96:913-20. [PMID: 15802614 DOI: 10.1161/01.res.0000164321.91452.00] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The novel immunomodulator FTY720 is effective in experimental models of transplantation and autoimmunity, and is currently undergoing Phase III clinical trials for prevention of kidney graft rejection. FTY720 is a structural analogue of sphingosine-1-phosphate (S1P) and activates several of the S1P receptors. We show that FTY720 induces endothelium-dependent arterial vasodilation in phenylephrine precontracted mouse aortae. Vasodilation did not occur in thoracic aortic rings from eNOS-deficient mice, implicating and effect dependent of activation of the eNOS/NO pathway. Accordingly, FTY720 induced NO release, Akt-dependent eNOS phosphorylation and activation in human endothelial cells. For biological efficacy, FTY720 required endogenous phosphorylation, since addition of the sphingosine kinase antagonist N',N-dimethylsphingosine (DMS) prevented activation of eNOS in vitro and inhibited vasodilation in isolated arteries. The endothelial phosphorylation of FTY720 was extremely rapid with almost complete conversion after 10 minutes as determined by mass spectrometry. Finally, we identified the lysophospholipid receptor S1P3 as the S1P receptor responsible for arterial vasodilation by FTY720, as the effect was completely abolished in arteries from S1P3-deficient mice. In summary, we have identified FTY720 as the first immunomodulator for prevention of organ graft rejection in clinical development that, in addition, positively affects the endothelium by stimulating NO production, and thus potentially displaying beneficial effects on transplant survival beyond classical T cell immunosuppression.
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Affiliation(s)
- Markus Tölle
- Med. Klinik IV, Charite-Campus Benjamin Franklin, Berlin, Germany
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577
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Sato K, Malchinkhuu E, Muraki T, Ishikawa K, Hayashi K, Tosaka M, Mochiduki A, Inoue K, Tomura H, Mogi C, Nochi H, Tamoto K, Okajima F. Identification of autotaxin as a neurite retraction-inducing factor of PC12 cells in cerebrospinal fluid and its possible sources. J Neurochem 2005; 92:904-14. [PMID: 15686493 DOI: 10.1111/j.1471-4159.2004.02933.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Abstract Cerebrospinal fluid (CSF) induced neurite retraction of differentiated PC12 cells; the action was observed in 15 min (a rapid response) and the activity further increased until 6 h (a long-acting response) during exposure of CSF to the cells. The CSF action was sensitive to monoglyceride lipase and diminished by homologous desensitization with lysophosphatidic acid (LPA) and by pretreatment with an LPA receptor antagonist Ki16425. Although fresh CSF contains LPA to some extent, the LPA content in the medium was increased during culture of PC12 cells with CSF. The rapid response was mimicked by exogenous LPA, and a long-acting response was duplicated by a recombinant autotaxin, lysophospholipase D (lyso-PLD). Although the lyso-PLD substrate lysophosphatidylcholine (LPC) was not detected in CSF, lyso-PLD activity and an approximately 120-kDa autotaxin protein were detected in CSF. On the other hand, LPC but not lyso-PLD activity was detected in the conditioned medium of a PC12 cell culture without CSF. Among neural cells examined, leptomeningeal cells expressed the highest lyso-PLD activity and autotaxin protein. These results suggest that leptomeningeal cells may work as one of the sources for autotaxin, which may play a critical role in LPA production and thereby regulate axonal and neurite morphological change.
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Affiliation(s)
- Koichi Sato
- Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan.
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578
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Novel Synthon of N-Boc-Phytosphingosine-3,4-thiocarbonate for the Synthesis of Sphingosine Derivatives. B KOREAN CHEM SOC 2005. [DOI: 10.5012/bkcs.2005.26.3.375] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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579
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van Meeteren LA, Ruurs P, Christodoulou E, Goding JW, Takakusa H, Kikuchi K, Perrakis A, Nagano T, Moolenaar WH. Inhibition of autotaxin by lysophosphatidic acid and sphingosine 1-phosphate. J Biol Chem 2005; 280:21155-61. [PMID: 15769751 DOI: 10.1074/jbc.m413183200] [Citation(s) in RCA: 166] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Autotaxin (ATX) or nucleotide pyrophosphatase/phosphodiesterase 2 (NPP2) is an NPP family member that promotes tumor cell motility, experimental metastasis, and angiogenesis. ATX primarily functions as a lysophospholipase D, generating the lipid mediator lysophosphatidic acid (LPA) from lysophosphatidylcholine. ATX uses a single catalytic site for the hydrolysis of both lipid and non-lipid phosphodiesters, but its regulation is not well understood. Using a new fluorescence resonance energy transfer-based phosphodiesterase sensor that reports ATX activity with high sensitivity, we show here that ATX is potently and specifically inhibited by LPA and sphingosine 1-phosphate (S1P) in a mixed-type manner (Ki approximately 10(-7) M). The homologous ecto-phosphodiesterase NPP1, which lacks lysophospholipase D activity, is insensitive to LPA and S1P. Our results suggest that, by repressing ATX activity, LPA can regulate its own biosynthesis in the extracellular environment, and they reveal a novel role for S1P as an inhibitor of ATX, in addition to its well established role as a receptor ligand.
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Affiliation(s)
- Laurens A van Meeteren
- Division of Cellular Biochemistry and Center for Biomedical Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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580
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Wang L, Radu CG, Yang LV, Bentolila LA, Riedinger M, Witte ON. Lysophosphatidylcholine-induced surface redistribution regulates signaling of the murine G protein-coupled receptor G2A. Mol Biol Cell 2005; 16:2234-47. [PMID: 15728718 PMCID: PMC1087231 DOI: 10.1091/mbc.e04-12-1044] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Intracellular trafficking and spatial dynamics of membrane receptors critically regulate receptor function. Using microscopic and subcellular fractionation analysis, we studied the localization of the murine G protein-coupled receptor G2A (muG2A). Evaluating green fluorescent protein-tagged, exogenously expressed as well as the endogenous muG2A, we observed that this receptor was spontaneously internalized and accumulated in endosomal compartments, whereas its surface expression was enhanced and stabilized by lysophosphatidylcholine (LPC) treatment. Monensin, a general inhibitor of recycling pathways, blocked LPC-regulated surface localization of muG2A as well as muG2A-dependent extracellular signal-regulated kinase (ERK) activation and cell migration induced by LPC treatment. Mutation of the conserved DRY motif (R-->A) enhanced the surface expression of muG2A, resulting in its resistance to monensin inhibition of ERK activation. Our data suggest that intracellular sequestration and surface expression regulated by LPC, rather than direct agonistic activity control the signaling responses of murine G2A toward LPC.
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Affiliation(s)
- Li Wang
- Department of Microbiology, Immunology, and Molecular Genetics, UCLA, Los Angeles, CA 90095, USA
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581
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Budnik LT, Brunswig-Spickenheier B. Differential effects of lysolipids on steroid synthesis in cells expressing endogenous LPA2 receptor. J Lipid Res 2005; 46:930-41. [PMID: 15716590 DOI: 10.1194/jlr.m400423-jlr200] [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: 11/20/2022] Open
Abstract
Incubation of ovarian luteal cells with the bioactive lipid mediator lysophosphatidic acid (LPA) for 180 min abolishes gonadotropin-induced steroid production with no attenuation of the cyclic AMP accumulation. Treatment with the lysolipid also diminishes [14C]steroid production in cells preloaded with either [14C]cholesterol or [14C]acetate. Neither the expression of steroidogenic acute regulatory (StAR) protein nor in vitro steroid synthesis is affected in isolated mitochondrial fractions. The LPA-induced attenuation of steroid production occurs only in the mid-cycle corpus luteum and is associated with a transient endogenous expression of mRNA for the lysophosphatidic acid A2 (LPA2) receptor (with no concomitant changes in the expression of LPA1 receptor). Expression of LPA2 is accompanied by LPA-induced sphingosine-1-phosphate (S1P) production. Because luteal cells, in the presence of the sphingosine kinase inhibitor dihydrosphingosine, can overcome the inhibitory effects of LPA on steroid synthesis, we suggest the possible requirement of intracellular S1P production. Interestingly, no LPA-induced inhibition of 8Br-cAMP-stimulated progesterone synthesis can be detected in Leydig tumor cell line MA10 cells expressing only LPA2 receptor. Surprisingly, however, exogenous S1P inhibits agonist-stimulated progesterone in both cell types by inhibiting cyclic AMP accumulation, suggesting different mechanisms of action.
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Affiliation(s)
- Lygia T Budnik
- Institute for Hormone and Fertility Research, Anatomy I, University Hospital Eppendorf, Martinistrasse 52, D-20246, Hamburg, Germany.
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582
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Girkontaite I, Sakk V, Wagner M, Borggrefe T, Tedford K, Chun J, Fischer KD. The sphingosine-1-phosphate (S1P) lysophospholipid receptor S1P3 regulates MAdCAM-1+ endothelial cells in splenic marginal sinus organization. ACTA ACUST UNITED AC 2005; 200:1491-501. [PMID: 15583019 PMCID: PMC2211946 DOI: 10.1084/jem.20041483] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Marginal zones (MZs) are microdomains in the spleen that contain various types of immune cells, including MZ B cells, MOMA1+ metallophilic macrophages, and mucosal addressin cell adhesion molecule 1 (MAdCAM-1)+ endothelial cells. MAdCAM-1+ and MOMA1+ cells line the sinus, that separates MZs from splenic follicles. Here we show that a receptor for the lysophospholipid sphingosine-1-phosphate (S1P), S1P3, is required for normal numbers of splenic immature and MZ B cells, and for S1P-induced chemotaxis of MZ B cells. S1P3 is also essential for proper alignment of MOMA1+ macrophages and MAdCAM-1+ endothelial cells along the marginal sinus. The lack of cohesion of the marginal sinus in S1P3−/− mice affects MZ B cell functions, as wild-type (WT) MZ B cells migrate more into S1P3−/− follicles than into WT follicles after treatment with lipopolysaccharide. Additionally, short-term homing experiments demonstrate that WT MZ B cells home to the S1P3−/− spleen in increased numbers, suggesting a role for the marginal sinus in regulating MZ B cells numbers. Moreover, S1P3−/− mice are defective in mounting immune responses to thymus-independent antigen type 2 due to defects in radiation-resistant cells in the spleen. These data identify lysophospholipids and the S1P3 receptor as essential regulators of the MZ sinus and its role as a barrier to the follicle.
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Affiliation(s)
- Irute Girkontaite
- Department of Physiological Chemistry, University of Ulm, Albert-Einstein-Allee 11, D-89069 Ulm, Germany
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583
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Gupta GP, Massagué J. Platelets and metastasis revisited: a novel fatty link. J Clin Invest 2005; 114:1691-3. [PMID: 15599391 PMCID: PMC535073 DOI: 10.1172/jci23823] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Platelets have long been suspected of having a role in cancer progression and metastasis that has largely been attributed to platelet-mediated enhancement of tumor cell survival, extravasation, and angiogenesis. A study in this issue of the JCI suggests that platelet-derived lysophosphatidic acid is coopted by aggressive breast and ovarian cancer cells as a tumor cell mitogen and promoter of osteolysis during bone metastasis.
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Affiliation(s)
- Gaorav P Gupta
- Cancer Biology and Genetics Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, New York 10021, USA
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584
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Damirin A, Tomura H, Komachi M, Tobo M, Sato K, Mogi C, Nochi H, Tamoto K, Okajima F. Sphingosine 1-Phosphate Receptors Mediate the Lipid-Induced cAMP Accumulation through Cyclooxygenase-2/Prostaglandin I2Pathway in Human Coronary Artery Smooth Muscle Cells. Mol Pharmacol 2004; 67:1177-85. [PMID: 15625281 DOI: 10.1124/mol.104.004317] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Sphingosine 1-phosphate (S1P) has been shown to exert a variety of biological responses through extracellular specific receptors or intracellular mechanisms. In the present study, we characterized a signaling pathway of S1P-induced cAMP accumulation in human coronary artery smooth muscle cells (CASMCs). S1P induced biphasic cAMP accumulation composed of a short-term and transient response (a peak at 2.5 min) and a late and sustained response ( approximately 4-6 h). The late phase of cAMP accumulation was parallel to the increment of cyclooxygenase-2 protein expression and was inhibited by N-[2-(cyclohexyloxyl)-4-nitrophenyl]-methane sulfonamide (NS398), a cyclooxygenase-2-specific inhibitor. We were surprised to find that the cyclooxygenase-2 inhibitor also inhibited short-term cAMP accumulation even when cyclooxygenase-2 protein expression was not yet increased. More interestingly, the short-term cAMP accumulation was also completely inhibited by pertussis toxin, an inhibitor of G(i/o) proteins. JTE-013, a specific antagonist for S1P(2) receptors, inhibited the S1P-induced cAMP accumulation. Furthermore, small interfering RNAs targeted for S1P(2) receptors significantly inhibited the S1P-induced cAMP accumulation. The cAMP response was also inhibited by specific inhibitors for phospholipase C, extracellular signal-regulated kinase pathways, and cytosolic phospholipase A(2). S1P actually activated these enzyme activities and stimulated prostaglandin I(2) (PGI(2)) synthesis. Finally, exogenously applied arachidonic acid and PGI(2) induced cAMP accumulation to a similar extent as S1P. In conclusion, S1P induced cAMP accumulation through S1P receptors, including S1P(2) receptor and G(i/o) protein-mediated stimulation of intracellular signaling pathways involving cyclooxygenase-2-dependent PGI(2) synthesis.
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Affiliation(s)
- Alatangaole Damirin
- Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi 371-8512, Japan
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585
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586
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Levkau B, Hermann S, Theilmeier G, van der Giet M, Chun J, Schober O, Schäfers M. High-density lipoprotein stimulates myocardial perfusion in vivo. Circulation 2004; 110:3355-9. [PMID: 15545521 DOI: 10.1161/01.cir.0000147827.43912.ae] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Several clinical studies have demonstrated a close association between plasma HDL cholesterol levels and endothelium-dependent vasodilation in peripheral arteries. In isolated arteries, HDL has been shown to mediate vasodilation via NO release. In vivo, administration of reconstituted HDL restored abnormal endothelial function of the brachial artery in hypercholesterolemic patients. However, no data are currently available on the effect of HDL on myocardial perfusion. METHODS AND RESULTS In this study, administration of human HDL enhanced incorporation of the perfusion tracer 99mTc-methoxyisobutylisonitrile (99mTc-MIBI) into the murine heart in vivo by approximately 18%. This increase was completely abolished in mice deficient for endothelial NO synthase. Because we have recently identified sphingosine 1-phosphate (S1P) as an important vasoactive component contained in HDL, we measured myocardial perfusion after administration of S1P in vivo. We observed an approximately 25% decrease in myocardial MIBI uptake, which was abolished in mice deficient for the S1P receptor S1P3. In S1P3-/- mice, the stimulatory effect of HDL on myocardial perfusion was preserved. CONCLUSIONS HDL increased myocardial perfusion under basal conditions in vivo via NO-dependent mechanisms, whereas S1P inhibited myocardial perfusion through the S1P3 receptor. Thus, HDL may reduce coronary risk via direct NO-mediated vasodilatory effects on the coronary circulation.
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Affiliation(s)
- Bodo Levkau
- Institute of Pathophysiology, Center of Internal Medicine, University Hospital Essen, Hufelandstrasse 55, 45122 Essen, Germany.
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587
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Murakami N, Yokomizo T, Okuno T, Shimizu T. G2A is a proton-sensing G-protein-coupled receptor antagonized by lysophosphatidylcholine. J Biol Chem 2004; 279:42484-91. [PMID: 15280385 DOI: 10.1074/jbc.m406561200] [Citation(s) in RCA: 187] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
G2A (from G2 accumulation) is a G-protein-coupled receptor (GPCR) that regulates the cell cycle, proliferation, oncogenesis, and immunity. G2A shares significant homology with three GPCRs including ovarian cancer GPCR (OGR1/GPR68), GPR4, and T cell death-associated gene 8 (TDAG8). Lysophosphatidylcholine (LPC) and sphingosylphosphorylcholine (SPC) were reported as ligands for G2A and GPR4 and for OGR1 (SPC only), and a glycosphingolipid psychosine was reported as ligand for TDAG8. As OGR1 and GPR4 were reported as proton-sensing GPCRs (Ludwig, M. G., Vanek, M., Guerini, D., Gasser, J. A., Jones, C. E., Junker, U., Hofstetter, H., Wolf, R. M., and Seuwen, K. (2003) Nature 425, 93-98), we evaluated the proton-sensing function of G2A. Transient expression of G2A caused significant activation of the zif 268 promoter and inositol phosphate (IP) accumulation at pH 7.6, and lowering extracellular pH augmented the activation only in G2A-expressing cells. LPC inhibited the pH-dependent activation of G2A in a dose-dependent manner in these assays. Thus, G2A is another proton-sensing GPCR, and LPC functions as an antagonist, not as an agonist, and regulates the proton-dependent activation of G2A.
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Affiliation(s)
- Naoka Murakami
- Department of Biochemistry, Faculty of Medicine, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan
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588
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Nofer JR, van der Giet M, Tölle M, Wolinska I, von Wnuck Lipinski K, Baba HA, Tietge UJ, Gödecke A, Ishii I, Kleuser B, Schäfers M, Fobker M, Zidek W, Assmann G, Chun J, Levkau B. HDL induces NO-dependent vasorelaxation via the lysophospholipid receptor S1P3. J Clin Invest 2004; 113:569-81. [PMID: 14966566 PMCID: PMC338256 DOI: 10.1172/jci18004] [Citation(s) in RCA: 187] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2003] [Accepted: 11/25/2003] [Indexed: 11/17/2022] Open
Abstract
HDL is a major atheroprotective factor, but the mechanisms underlying this effect are still obscure. HDL binding to scavenger receptor-BI has been shown to activate eNOS, although the responsible HDL entities and signaling pathways have remained enigmatic. Here we show that HDL stimulates NO release in human endothelial cells and induces vasodilation in isolated aortae via intracellular Ca2+ mobilization and Akt-mediated eNOS phosphorylation. The vasoactive effects of HDL could be mimicked by three lysophospholipids present in HDL: sphingosylphosphorylcholine (SPC), sphingosine-1-phosphate (S1P), and lysosulfatide (LSF). All three elevated intracellular Ca2+ concentration and activated Akt and eNOS, which resulted in NO release and vasodilation. Deficiency of the lysophospholipid receptor S1P3 (also known as LPB3 and EDG3) abolished the vasodilatory effects of SPC, S1P, and LSF and reduced the effect of HDL by approximately 60%. In endothelial cells from S1P3-deficient mice, Akt phosphorylation and Ca2+ increase in response to HDL and lysophospholipids were severely reduced. In vivo, intra-arterial administration of HDL or lysophospholipids lowered mean arterial blood pressure in rats. In conclusion, we identify HDL as a carrier of bioactive lysophospholipids that regulate vascular tone via S1P3-mediated NO release. This mechanism may contribute to the vasoactive effect of HDL and represent a novel aspect of its antiatherogenic function.
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MESH Headings
- Animals
- Aorta/anatomy & histology
- Aorta/metabolism
- Calcium/metabolism
- Cells, Cultured
- Endothelium, Vascular/cytology
- Endothelium, Vascular/metabolism
- Enzyme Activation
- Enzyme Inhibitors/metabolism
- Female
- Humans
- In Vitro Techniques
- Lipoproteins, HDL/metabolism
- Lysophospholipids/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Nitric Oxide/metabolism
- Nitric Oxide Synthase/metabolism
- Nitric Oxide Synthase Type II
- Nitric Oxide Synthase Type III
- Phosphorylation
- Protein Serine-Threonine Kinases
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins c-akt
- Rats
- Rats, Inbred WKY
- Rats, Wistar
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Receptors, Lysophospholipid
- Vasodilation/physiology
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Affiliation(s)
- Jerzy-Roch Nofer
- Institut für Klinische Chemie und Laboratoriumsmedizin, Westfälische Wilhelms-Universität, Münster, Germany
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589
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Abstract
The many biological responses documented for lysophospholipids that include lysophosphatidic acid and sphingosine 1-phosphate can be mechanistically attributed to signaling through specific G protein-coupled receptors. At least nine receptors have now been identified, and the total number is likely to be larger. In this brief review, we note cogent features of lysophospholipid receptors, including the current nomenclature, signaling properties, development of agonists and antagonists, and physiological functions.
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Affiliation(s)
- Brigitte Anliker
- 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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590
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Kingsbury MA, Rehen SK, Contos JJA, Higgins CM, Chun J. Non-proliferative effects of lysophosphatidic acid enhance cortical growth and folding. Nat Neurosci 2003; 6:1292-9. [PMID: 14625558 DOI: 10.1038/nn1157] [Citation(s) in RCA: 190] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2003] [Accepted: 10/16/2003] [Indexed: 11/08/2022]
Abstract
Lysophosphatidic acid (LPA) is a phospholipid that has extracellular signaling properties mediated by G protein-coupled receptors. Two LPA receptors, LPA(1) and LPA(2), are expressed in the embryonic cerebral cortex, suggesting roles for LPA signaling in cortical formation. Here we report that intact cerebral cortices exposed to extracellular LPA ex vivo rapidly increased in width and produced folds resembling gyri, which are not normally present in mouse brains and are absent in LPA(1) LPA(2) double-null mice. Mechanistically, growth was not due to increased proliferation but rather to receptor-dependent reduced cell death and increased terminal mitosis of neural progenitor cells (NPCs). Our results implicate extracellular lipid signals as new influences on brain formation during embryonic development.
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Affiliation(s)
- Marcy A Kingsbury
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, ICND 118, La Jolla, California 92037, USA
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