351
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Im DS. Pharmacological tools for lysophospholipid GPCRs: development of agonists and antagonists for LPA and S1P receptors. Acta Pharmacol Sin 2010; 31:1213-22. [PMID: 20729877 DOI: 10.1038/aps.2010.135] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Previous studies on lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) using various approaches have shown that both the molecules can act as intercellular signaling molecules. The discovery of the Edg subfamily of G-protein-coupled receptors (GPCRs) (later renamed LPA(1-3) and S1P(1-5)) for these molecules has opened up a new avenue for pathophysiological research on lysophospholipids. Genetic and molecular studies on lysophospholipid GPCRs have elucidated pathophysiological impacts and roles in cellular signaling pathways. Recently, lysophospholipid GPCR genes have been used to develop receptor subtype-selective agonists and antagonists. The discovery of FTY720, a novel immune modulator, along with other chemical tools, has provided a means of elucidating the functions of each lysophospholipid GPCR on an organ and the whole body level. This communication attempts to retrospectively review the development of agonists and antagonists for lysophospholipid GPCRs, provide integrated information on pharmacological tools for lysophospholipid GPCR signaling, and speculate on future drug development.
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352
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Tigyi G. Aiming drug discovery at lysophosphatidic acid targets. Br J Pharmacol 2010; 161:241-70. [PMID: 20735414 PMCID: PMC2989581 DOI: 10.1111/j.1476-5381.2010.00815.x] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 02/12/2010] [Accepted: 03/20/2010] [Indexed: 12/22/2022] Open
Abstract
Lysophosphatidic acid (LPA, 1-radyl-2-hydroxy-sn-glycero-3-phosphate) is the prototype member of a family of lipid mediators and second messengers. LPA and its naturally occurring analogues interact with G protein-coupled receptors on the cell surface and a nuclear hormone receptor within the cell. In addition, there are several enzymes that utilize LPA as a substrate or generate it as a product and are under its regulatory control. LPA is present in biological fluids, and attempts have been made to link changes in its concentration and molecular composition to specific disease conditions. Through their many targets, members of the LPA family regulate cell survival, apoptosis, motility, shape, differentiation, gene transcription, malignant transformation and more. The present review depicts arbitrary aspects of the physiological and pathophysiological actions of LPA and attempts to link them with select targets. Many of us are now convinced that therapies targeting LPA biosynthesis and signalling are feasible for the treatment of devastating human diseases such as cancer, fibrosis and degenerative conditions. However, successful targeting of the pathways associated with this pleiotropic lipid will depend on the future development of as yet undeveloped pharmacons.
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Affiliation(s)
- Gabor Tigyi
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN, USA.
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353
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Liu YB, Kharode Y, Bodine PVN, Yaworsky PJ, Robinson JA, Billiard J. LPA induces osteoblast differentiation through interplay of two receptors: LPA1 and LPA4. J Cell Biochem 2010; 109:794-800. [PMID: 20069565 DOI: 10.1002/jcb.22471] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The bioactive phospholipid, lysophosphatidic acid (LPA), acting through at least five distinct receptors LPA1-LPA5, plays important roles in numerous biological processes. Here we report that LPA induces osteoblastic differentiation of human mesenchymal stem cells hMSC-TERT. We find that hMSC-TERT mostly express two LPA receptors, LPA1 and LPA4, and undergo osteoblastic differentiation in serum-containing medium. Inhibition of LPA1 with Ki16425 completely abrogates osteogenesis, indicating that this process is mediated by LPA in the serum through activation of LPA1. In contrast to LPA1, down-regulation of LPA4 expression with shRNA significantly increases osteogenesis, suggesting that this receptor normally exerts negative effects on differentiation. Mechanistically, we find that in hMSC-TERT, LPA induces a rise in both cAMP and Ca(2+). The rise in Ca(2+) is completely abolished by Ki16425, whereas LPA-mediated cAMP increase is not sensitive to Ki16425. To test if LPA signaling pathways controlling osteogenesis in vitro translate into animal physiology, we evaluated the bones of LPA4-deficient mice. Consistent with the ability of LPA4 to inhibit osteoblastic differentiation of stem cells, LPA4-deficient mice have increased trabecular bone volume, number, and thickness.
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Affiliation(s)
- Yao-Bin Liu
- Tissue Repair, Pfizer, Inc., Collegeville, Pennsylvania 19426, USA
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354
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RICHMOND GREGORYS, GIBELLINI FEDERICA, YOUNG SIMONA, MAJOR LOUISE, DENTON HELEN, LILLEY ALISON, SMITH TERRYK. Lipidomic analysis of bloodstream and procyclic form Trypanosoma brucei. Parasitology 2010; 137:1357-92. [PMID: 20602846 PMCID: PMC3744936 DOI: 10.1017/s0031182010000715] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The biological membranes of Trypanosoma brucei contain a complex array of phospholipids that are synthesized de novo from precursors obtained either directly from the host, or as catabolised endocytosed lipids. This paper describes the use of nanoflow electrospray tandem mass spectrometry and high resolution mass spectrometry in both positive and negative ion modes, allowing the identification of approximately 500 individual molecular phospholipids species from total lipid extracts of cultured bloodstream and procyclic form T. brucei. Various molecular species of all of the major subclasses of glycerophospholipids were identified including phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol as well as phosphatidic acid, phosphatidylglycerol and cardolipin, and the sphingolipids sphingomyelin, inositol phosphoceramide and ethanolamine phosphoceramide. The lipidomic data obtained in this study will aid future biochemical phenotyping of either genetically or chemically manipulated commonly used bloodstream and procyclic strains of Trypanosoma brucei. Hopefully this will allow a greater understanding of the bizarre world of lipids in this important human pathogen.
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Affiliation(s)
| | - FEDERICA GIBELLINI
- Centre for Biomolecular Sciences, The North Haugh, The University, St. Andrews, KY16 9ST, Scotland, U.K
| | - SIMON A. YOUNG
- Centre for Biomolecular Sciences, The North Haugh, The University, St. Andrews, KY16 9ST, Scotland, U.K
| | - LOUISE MAJOR
- Centre for Biomolecular Sciences, The North Haugh, The University, St. Andrews, KY16 9ST, Scotland, U.K
| | - HELEN DENTON
- Centre for Biomolecular Sciences, The North Haugh, The University, St. Andrews, KY16 9ST, Scotland, U.K
| | - ALISON LILLEY
- Centre for Biomolecular Sciences, The North Haugh, The University, St. Andrews, KY16 9ST, Scotland, U.K
| | - TERRY K. SMITH
- Centre for Biomolecular Sciences, The North Haugh, The University, St. Andrews, KY16 9ST, Scotland, U.K
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355
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Seo J, Koo NY, Choi WY, Kang JA, Min J, Jo SH, Lee S, Oh SB, Kim JS, Lee JH, Choi SY, Park K. Sphingosine-1-phosphate Signaling in Human Submandibular Cells. J Dent Res 2010; 89:1148-53. [DOI: 10.1177/0022034510376044] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Sphingosine-1-phosphate (S1P) is a significant lipid messenger modulating many physiological responses. S1P plays a critical role in autoimmune disease and is suggested to be involved in Sjögren’s syndrome pathology. However, the mechanism of S1P signaling in salivary glands is unclear. Here we studied the effects of S1P on normal human submandibular gland cells. S1P increased levels of the intracellular Ca2+ concentration ([Ca2+]i), which was inhibited by pre-treatment with U73122 or 2-aminoethoxydiphenyl borate (2-APB). Pre-treated S1P did not inhibit subsequent carbachol-induced [Ca2+]i increase, which suggests that S1P and muscarinic signaling are independent of each other. S1P1, S1P2, and S1P3 receptors SphK1 and SphK2 were commonly expressed in human salivary gland cells. S1P, but not carbachol, induces the expression of interleukin-6 and Fas. Our results suggest that S1P triggers Ca2+ signaling and the apoptotic pathway in normal submandibular gland cells, which suggests in turn that S1P affects the progression of Sjögren’s syndrome.
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Affiliation(s)
| | | | | | | | | | - S.-H. Jo
- Department of Physiology, Institute of Medical Science, Kangwon National University School of Medicine, Chuncheon 200-701, Korea
| | | | | | | | - J.-H. Lee
- Department of Oral and Maxillofacial Surgery, Dental Research Institute, Seoul National University School of Dentistry, Seoul 110–749, Korea
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356
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Kosanam H, Ma F, He H, Ramagiri S, Gududuru V, Tigyi GJ, Van Rompay K, Miller DD, Yates CR. Development of an LC-MS/MS assay to determine plasma pharmacokinetics of the radioprotectant octadecenyl thiophosphate (OTP) in monkeys. J Chromatogr B Analyt Technol Biomed Life Sci 2010; 878:2379-83. [PMID: 20719582 DOI: 10.1016/j.jchromb.2010.07.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 06/28/2010] [Accepted: 07/08/2010] [Indexed: 10/19/2022]
Abstract
Octadecenyl thiophosphate (OTP), a synthetic analogue of the lysophospholipid growth factor lysophosphatidic acid (LPA), significantly reduces mortality following a lethal dose of LD(80/30) radiation exposure in a mouse model of whole-body irradiation. To facilitate dose scaling between species, we developed a novel liquid chromatography/tandem mass spectrometry (LC-MS/MS) for the preclinical pharmacokinetic characterization of OTP in monkeys. Sample extraction was carried out using a butanol based liquid-liquid extraction method. A partially deuterated OTP analogue was used as internal standard (IS). OTP and IS were separated by reversed-phase liquid chromatography on a C-8 column using 10mM ammonium acetate and acetonitrile. A triple quadrupole mass spectrometer operating in the negative electrospray ionization mode with multiple reaction monitoring was used to detect OTP and IS transitions of m/z 363.1-->95.0 and 403.1-->95.0. The method was applied to determine pharmacokinetic parameters in monkeys receiving a single oral OTP dose (3mg/kg). OTP is readily absorbed with a relatively long half-life which supports further preclinical testing of OTP as a radioprotectant in monkeys.
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Affiliation(s)
- Hari Kosanam
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Advanced Cancer Detection Center, Samuel Lunenfeld Research Institute, Toronto, ON, Canada
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357
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Abstract
Fingolimod (FTY720) is a first-in-class orally bioavailable compound that has shown efficacy in advanced clinical trials for the treatment of multiple sclerosis (MS). In vivo, fingolimod is phosphorylated to form fingolimod-phosphate, which resembles naturally occurring sphingosine 1-phosphate (S1P), an extracellular lipid mediator whose major effects are mediated by cognate G protein-coupled receptors. There are at least 5 S1P receptor subtypes, known as S1P subtypes 1-5 (S1P1-5), 4 of which bind fingolimod-phosphate. These receptors are expressed on a wide range of cells that are involved in many biological processes relevant to MS. S1P1 plays a key role in the immune system, regulating lymphocyte egress from lymphoid tissues into the circulation. Fingolimod-phosphate initially activates lymphocyte S1P1 via high-affinity receptor binding yet subsequently induces S1P1 down-regulation that prevents lymphocyte egress from lymphoid tissues, thereby reducing autoaggressive lymphocyte infiltration into the central nervous system (CNS). S1P receptors are also expressed by many CNS cell types and have been shown to influence cell proliferation, morphology, and migration. Fingolimod crosses the blood-brain barrier and may therefore have direct CNS effects, distinguishing it from immunologically targeted MS therapies. Prophylactic administration of fingolimod to animals with experimental autoimmune encephalitis (EAE), a model of MS, completely prevents development of EAE features, whereas therapeutic administration significantly reduces clinical severity of EAE. Therapeutic efficacy observed in animal studies has been substantiated in phase 2 and 3 trials involving patients with relapsing or relapsing-remitting MS.
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358
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Yamane M, Furuta D, Fukushima N. Lysophosphatidic acid influences initial neuronal polarity establishment. Neurosci Lett 2010; 480:154-7. [PMID: 20561563 DOI: 10.1016/j.neulet.2010.06.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Revised: 05/25/2010] [Accepted: 06/08/2010] [Indexed: 01/15/2023]
Abstract
Neuronal polarity is specified by neurite determination into axons and dendrites. Its establishment requires both extrinsic signals, which regulate axon and dendrite development through repulsive or attractive actions, and intrinsic cellular mechanisms, which include rearrangement and selective transport of the cytoskeleton and localization of intracellular organelles. However, it remains unclear how extrinsic signals activate intrinsic cellular mechanisms to establish neuronal polarity. Here, we examine the effects of lysophosphatidic acid (LPA), a signaling lipid that induces cytoskeletal rearrangement in neuronal cells, on neuronal polarity establishment. In hippocampal neuronal cultures where a concentration gradient of LPA was formed, the bases of axons were located predominantly at the side distal to the LPA source. Furthermore, Golgi apparatus were also positioned distally as early as 1h after exposure to the LPA source, suggesting that LPA signaling is involved in the initial determination of the area where an axon sprouts, and thereby the establishment of neuronal polarity.
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Affiliation(s)
- Masayuki Yamane
- Division of Molecular Neurobiology, Department of Life Science, Kinki University, Kowakae 3-4-1, Higashiosaka 577-8502, Japan
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359
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Diversity of lysophosphatidic acid receptor-mediated intracellular calcium signaling in early cortical neurogenesis. J Neurosci 2010; 30:7300-9. [PMID: 20505096 DOI: 10.1523/jneurosci.6151-09.2010] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Lysophosphatidic acid (LPA) is a membrane-derived lysophospholipid that can induce pleomorphic effects in neural progenitor cells (NPCs) from the cerebral cortex, including alterations in ionic conductance. LPA-induced, calcium-mediated conductance changes have been reported; however, the underlying molecular mechanisms have not been determined. We show here that activation of specific cognate receptors accounts for nearly all intracellular calcium responses evoked by LPA in acutely cultured nestin-positive NPCs from the developing mouse cerebral cortex. Fast-onset changes in intracellular calcium levels required release from thapsigargin-sensitive stores by a pertussis toxin-insensitive mechanism. The influx of extracellular calcium through Cd(2+)/Ni(2+)-insensitive influx pathways, approximately one-half of which were Gd(3+) sensitive, contributed to the temporal diversity of responses. Quantitative reverse transcription-PCR revealed the presence of all five known LPA receptors in primary NPCs, with prominent expression of LPA(1), LPA(2), and LPA(4). Combined genetic and pharmacological studies indicated that NPC responses were mediated by LPA(1) (approximately 30% of the cells), LPA(2) (approximately 30%), a combination of receptors on single cells (approximately 30%), and non-LPA(1,2,3) pathways (approximately 10%). LPA responsivity was significantly reduced in more differentiated TuJ1(+) cells within cultures. Calcium transients in a large proportion of LPA-responsive NPCs were also initiated by the closely related signaling lipid S1P (sphingosine-1-phosphate). These data demonstrate for the first time the involvement of LPA receptors in mediating surprisingly diverse NPC calcium responses involving multiple receptor subtypes that function within a single cell. Compared with other known factors, lysophospholipids represent the major activator of calcium signaling identified within NPCs at this early stage in corticogenesis.
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360
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Aktas O, Küry P, Kieseier B, Hartung HP. Fingolimod is a potential novel therapy for multiple sclerosis. Nat Rev Neurol 2010; 6:373-82. [PMID: 20551946 DOI: 10.1038/nrneurol.2010.76] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Fingolimod (also known as FTY720) is an orally available sphingosine-1-phosphate (S1P) receptor modulator that has unique and potent immunoregulatory properties. Mechanistic studies indicate that on phosphorylation fingolimod can bind with high affinity to S1P(1) receptors. Persistent modulation of lymphocyte S1P(1) receptors by fingolimod and the subsequent internalization of these receptors inhibits lymphocyte egress from the lymph nodes, and prevents these cells from infiltrating inflammatory lesions in the CNS. Results of two phase III studies--FREEDOMS and TRANSFORMS--support previous phase II trial observations indicating that fingolimod exerts powerful anti-inflammatory effects in relapsing-remitting multiple sclerosis (MS). Fingolimod might, therefore, be one of the first orally active drug therapies available for the treatment of relapsing-remitting MS. Moreover, results from preclinical studies suggest that fingolimod might promote neural repair in vivo. In this article, we review the background to these findings, present the proposed immunological and neurobiological profile of fingolimod, discuss the data from the FREEDOMS and TRANSFORMS trials, and provide an expert opinion regarding the future of next-generation S1P receptor modulators for MS therapy.
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Affiliation(s)
- Orhan Aktas
- Department of Neurology, Heinrich-Heine-University of Düsseldorf, 40225 Düsseldorf, Germany
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361
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Müller R, Berliner C, Leptin J, Pörtner D, Bialecki W, Kleuser B, Schumacher U, Milićević NM. Expression of sphingosine-1-phosphate receptors and lysophosphatidic acid receptors on cultured and xenografted human colon, breast, melanoma, and lung tumor cells. Tumour Biol 2010; 31:341-9. [PMID: 20480410 DOI: 10.1007/s13277-010-0043-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2009] [Accepted: 04/21/2010] [Indexed: 12/25/2022] Open
Abstract
The lysophospholipids sphingosine-1-phosphate (S1P) and lysophosphatidic acid (LPA) are small lipid molecules with a variety of physiological roles. Additionally, their involvement in the initiation and progression of malignant tumors has been increasingly recognized in recent years. However, the data on the expression of S1P and LPA receptors on different cancer cells are very few. Real-time polymerase chain reaction was used for the analysis of mRNA expression of five S1P((1-5)) and three LPA((1-3)) receptors on a large panel of 13 colon, breast, melanoma, and lung cancer cell lines. Furthermore, the modulation of S1P and LPA receptor mRNA expression was studied upon xenotransplantation of tumor cells into severe combined immunodeficient (SCID) mice. The S1P and LPA receptors were expressed to a variable degree on all tumor cell lines tested (with exception of colon cancer SW480). Most notably, tumor cell lines in vitro expressed S1P(2) mRNA that was down-regulated upon xenotransplantation, whereas LPA(2) receptor mRNA was strongly expressed both in vitro and in vivo (except by breast cancer cells). The latter was especially distinctive for small cell lung tumor cells. The S1P and LPA receptors are differentially expressed on tumor cell lines in vitro. Their expression is modulated upon xenografting into SCID mice in vivo.
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Affiliation(s)
- Reinhard Müller
- Center for Experimental Medicine, Institute of Anatomy II: Experimental Morphology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
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362
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Qi X, Okamoto Y, Murakawa T, Wang F, Oyama O, Ohkawa R, Yoshioka K, Du W, Sugimoto N, Yatomi Y, Takuwa N, Takuwa Y. Sustained delivery of sphingosine-1-phosphate using poly(lactic-co-glycolic acid)-based microparticles stimulates Akt/ERK-eNOS mediated angiogenesis and vascular maturation restoring blood flow in ischemic limbs of mice. Eur J Pharmacol 2010; 634:121-31. [DOI: 10.1016/j.ejphar.2010.02.038] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Revised: 01/25/2010] [Accepted: 02/14/2010] [Indexed: 10/19/2022]
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363
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Hsu KH, Wang SY, Chu FH, Shaw JF. Characterization and heterologous expression of a novel lysophospholipase gene fromAntrodia cinnamomea. J Appl Microbiol 2010; 108:1712-22. [DOI: 10.1111/j.1365-2672.2009.04569.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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364
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Gierse J, Thorarensen A, Beltey K, Bradshaw-Pierce E, Cortes-Burgos L, Hall T, Johnston A, Murphy M, Nemirovskiy O, Ogawa S, Pegg L, Pelc M, Prinsen M, Schnute M, Wendling J, Wene S, Weinberg R, Wittwer A, Zweifel B, Masferrer J. A novel autotaxin inhibitor reduces lysophosphatidic acid levels in plasma and the site of inflammation. J Pharmacol Exp Ther 2010; 334:310-7. [PMID: 20392816 DOI: 10.1124/jpet.110.165845] [Citation(s) in RCA: 169] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Autotaxin is the enzyme responsible for the production of lysophosphatidic acid (LPA) from lysophosphatidyl choline (LPC), and it is up-regulated in many inflammatory conditions, including but not limited to cancer, arthritis, and multiple sclerosis. LPA signaling causes angiogenesis, mitosis, cell proliferation, and cytokine secretion. Inhibition of autotaxin may have anti-inflammatory properties in a variety of diseases; however, this hypothesis has not been tested pharmacologically because of the lack of potent inhibitors. Here, we report the development of a potent autotaxin inhibitor, PF-8380 [6-(3-(piperazin-1-yl)propanoyl)benzo[d]oxazol-2(3H)-one] with an IC(50) of 2.8 nM in isolated enzyme assay and 101 nM in human whole blood. PF-8380 has adequate oral bioavailability and exposures required for in vivo testing of autotaxin inhibition. Autotaxin's role in producing LPA in plasma and at the site of inflammation was tested in a rat air pouch model. The specific inhibitor PF-8380, dosed orally at 30 mg/kg, provided >95% reduction in both plasma and air pouch LPA within 3 h, indicating autotaxin is a major source of LPA during inflammation. At 30 mg/kg PF-8380 reduced inflammatory hyperalgesia with the same efficacy as 30 mg/kg naproxen. Inhibition of plasma autotaxin activity correlated with inhibition of autotaxin at the site of inflammation and in ex vivo whole blood. Furthermore, a close pharmacokinetic/pharmacodynamic relationship was observed, which suggests that LPA is rapidly formed and degraded in vivo. PF-8380 can serve as a tool compound for elucidating LPA's role in inflammation.
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Affiliation(s)
- James Gierse
- Pfizer Inflammation Research, Chesterfield, MO 63017, USA.
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365
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Castilla-Ortega E, Sánchez-López J, Hoyo-Becerra C, Matas-Rico E, Zambrana-Infantes E, Chun J, De Fonseca FR, Pedraza C, Estivill-Torrús G, Santin LJ. Exploratory, anxiety and spatial memory impairments are dissociated in mice lacking the LPA1 receptor. Neurobiol Learn Mem 2010; 94:73-82. [PMID: 20388543 DOI: 10.1016/j.nlm.2010.04.003] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2010] [Revised: 03/23/2010] [Accepted: 04/07/2010] [Indexed: 01/30/2023]
Abstract
Lysophosphatidic acid (LPA) is a new, intercellular signalling molecule in the brain that has an important role in adult hippocampal plasticity. Mice lacking the LPA(1) receptor exhibit motor, emotional and cognitive alterations. However, the potential relationship among these concomitant impairments was unclear. Wild-type and maLPA(1)-null mice were tested on the hole-board for habituation and spatial learning. MaLPA(1)-null mice exhibited reduced exploration in a novel context and a defective intersession habituation that also revealed increased anxiety-like behaviour throughout the hole-board testing. In regard to spatial memory, maLPA(1) nulls failed to reach the controls' performance at the end of the reference memory task. Moreover, their defective working memory on the first training day suggested a delayed acquisition of the task's working memory rule, which is also a long term memory component. The temporal interval between trials and the task's difficulty may explain some of the deficits found in these mice. Principal components analysis revealed that alterations found in each behavioural dimension were independent. Therefore, exploratory and emotional impairments did not account for the cognitive deficits that may be attributed to maLPA(1) nulls' hippocampal malfunction.
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Affiliation(s)
- Estela Castilla-Ortega
- Departamento de Psicobiología y Metodología de las CC, Universidad de Málaga, Campus de Teatinos, 29071 Málaga, Spain
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366
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Lipid metabolism in Trypanosoma brucei. Mol Biochem Parasitol 2010; 172:66-79. [PMID: 20382188 DOI: 10.1016/j.molbiopara.2010.04.001] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Revised: 03/31/2010] [Accepted: 04/01/2010] [Indexed: 11/28/2022]
Abstract
Trypanosoma brucei membranes consist of all major eukaryotic glycerophospholipid and sphingolipid classes. These are de novo synthesized from precursors obtained either from the host or from catabolised endocytosed lipids. In recent years, substantial progress has been made in the molecular and biochemical characterisation of several of these lipid biosynthetic pathways, using gene knockout or RNA interference strategies or by enzymatic characterization of individual reactions. Together with the completed genome, these studies have highlighted several possible differences between mammalian and trypanosome lipid biosynthesis that could be exploited for the development of drugs against the diseases caused by these parasites.
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367
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Wakabayashi N, Tsujino M, Tajiri M, Taki M, Koshino A, Ikeda H, Fukushima N, Tsujiuchi T. No Mutations of Lysophosphatidic Acid Receptor Genes in Lung Adenocarcinomas Induced by N-Nitrosobis(2-hydroxypropyl)amine in Rats. J Toxicol Pathol 2010; 23:63-6. [PMID: 22272013 PMCID: PMC3234649 DOI: 10.1293/tox.23.63] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Accepted: 11/19/2009] [Indexed: 01/08/2023] Open
Abstract
Lysophosphatidic acid (LPA) is a bioactive phospholipid that stimulates cell
proliferation and migration, and protects cells from apoptosis. It interacts
with specific G protein-coupled transmembrane receptors. Recently, frequent
mutations of the LPA receptor-1 (LPA1) gene were detected in rat lung
adenocarcinomas induced by N-nitrosobis(2-hydroxypropyl)amine (BHP). In this
study, to evaluate the involvement of other LPA receptor gene alterations during
lung carcinogenesis, we investigated mutations of the LPA2, LPA3, LPA4 and LPA5
genes in lung adenocarcinomas induced by BHP in rats. Fifteen male Wistar rats,
6 weeks of age, were given 2000 ppm BHP in their drinking water for 12 weeks and
then maintained without further treatment until sacrifice at 25 weeks, and 15
adenocarcinomas were obtained. Genomic DNAs were extracted from frozen tissues,
and the LPA2, LPA3, LPA4 and LPA5 genes were examined for mutations, using
polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP)
analysis. No mutations of LPA2, LPA3, LPA4 and LPA5 were detected in the 15
adenocarcinomas. These results suggest that alterations due to LPA2, LPA3, LPA4
and LPA5 gene mutations might not be involved in the development of lung
adenocarcinomas induced by BHP in rats.
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Affiliation(s)
- Naoko Wakabayashi
- Laboratory of Cancer Biology and Bioinformatics, Department of
Life Science, Faculty of Science and Engineering, Kinki University, 3–4–1
Kowakae, Higashiosaka, Osaka 577-8502, Japan
| | - Megumu Tsujino
- Laboratory of Cancer Biology and Bioinformatics, Department of
Life Science, Faculty of Science and Engineering, Kinki University, 3–4–1
Kowakae, Higashiosaka, Osaka 577-8502, Japan
| | - Masaki Tajiri
- Laboratory of Cancer Biology and Bioinformatics, Department of
Life Science, Faculty of Science and Engineering, Kinki University, 3–4–1
Kowakae, Higashiosaka, Osaka 577-8502, Japan
| | - Midori Taki
- Laboratory of Cancer Biology and Bioinformatics, Department of
Life Science, Faculty of Science and Engineering, Kinki University, 3–4–1
Kowakae, Higashiosaka, Osaka 577-8502, Japan
| | - Ayumi Koshino
- Laboratory of Cancer Biology and Bioinformatics, Department of
Life Science, Faculty of Science and Engineering, Kinki University, 3–4–1
Kowakae, Higashiosaka, Osaka 577-8502, Japan
| | - Hiroko Ikeda
- Laboratory of Cancer Biology and Bioinformatics, Department of
Life Science, Faculty of Science and Engineering, Kinki University, 3–4–1
Kowakae, Higashiosaka, Osaka 577-8502, Japan
| | - Nobuyuki Fukushima
- Laboratory of Molecular Neurobiology, Department of Life
Science, Faculty of Science and Engineering, Kinki University, 3–4–1 Kowakae,
Higashiosaka, Osaka 577-8502, Japan
| | - Toshifumi Tsujiuchi
- Laboratory of Cancer Biology and Bioinformatics, Department of
Life Science, Faculty of Science and Engineering, Kinki University, 3–4–1
Kowakae, Higashiosaka, Osaka 577-8502, Japan
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368
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Martinez-Pinna J, Gurung IS, Mahaut-Smith MP, Morales A. Direct voltage control of endogenous lysophosphatidic acid G-protein-coupled receptors in Xenopus oocytes. J Physiol 2010; 588:1683-93. [PMID: 20351041 DOI: 10.1113/jphysiol.2009.183418] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Lysophosphatidic acid (LPA) G-protein-coupled receptors (GPCRs) play important roles in a variety of physiological and pathophysiological processes, including cell proliferation, angiogenesis, central nervous system development and carcinogenesis. Whilst many ion channels and transporters are recognized to be controlled by a change in cell membrane potential, little is known about the voltage dependence of other proteins involved in cell signalling. Here, we show that the InsP(3)-mediated Ca(2+) response stimulated by the endogenous LPA GPCR in Xenopus oocytes is potentiated by membrane depolarization. Depolarization was able to repetitively stimulate transient [Ca(2+)](i) increases after the initial agonist-evoked response. In addition, the initial rate and amplitude of the LPA-dependent Ca(2+) response were significantly modulated by the steady holding potential over the physiological range, such that the response to LPA was potentiated at depolarized potentials and inhibited at hyperpolarized potentials. Enhancement of LPA receptor-evoked Ca(2+) mobilization by membrane depolarization was observed over a wide range of agonist concentrations. Importantly, the amplitude of the depolarization-evoked intracellular Ca(2+) increase displayed an inverse relationship with agonist concentration such that the greatest effect of voltage was observed at near-threshold levels of agonist. Voltage-dependent Ca(2+) release was not induced by direct elevation of InsP(3) or by activation of heterotrimeric G-proteins in the absence of agonist, indicating that the LPA GPCR itself represents the primary site of action of membrane voltage. This novel modulation of LPA signalling by membrane potential may have important consequences for control of Ca(2+) signals both in excitable and non-excitable tissues.
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Affiliation(s)
- Juan Martinez-Pinna
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, E-03080, Spain.
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369
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The discovery of novel experimental therapies for inflammatory arthritis. Mediators Inflamm 2010; 2009:698769. [PMID: 20339519 PMCID: PMC2842969 DOI: 10.1155/2009/698769] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Accepted: 12/21/2009] [Indexed: 12/16/2022] Open
Abstract
Conventional and biologic disease-modifying antirheumatic drugs have revolutionized the medical therapy of inflammatory arthritis. However, it remains unclear as to what can be done to treat immune-mediated chronic inflammation after patients become refractory to these therapies or develop serious side-effects and/or infections forcing drug withdrawal. Because of these concerns it is imperative that novel targets be continuously identified and experimental strategies designed to test potential arthritis interventions in vitro, but more importantly, in well-validated animal models of inflammatory arthritis. Over the past few years, sphingosine-1-phosphate, interleukin-7 receptor, spleen tyrosine kinase, extracellular signal-regulated kinase, mitogen-activated protein kinase 5/p38 kinase regulated/activated protein kinase, micro-RNAs, tumor necrosis factor-related apoptosis inducing ligand and the polyubiquitin-proteasome pathway were identified as promising novel targets for potential antiarthritis drug development. Indeed several experimental compounds alter the biological activity of these targets and have shown clinical efficacy in animal models of arthritis. A few of them have even entered the first phase of human clinical trials.
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370
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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: 648] [Impact Index Per Article: 46.3] [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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371
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Abstract
Lysophosphatidic acid (LPA; 1- or 2-acyl-sn-glycerol-3-phosphate) is a phospholipid that is involved in numerous normal physiological and pathological processes such as brain development, blood vessel formation, embryo implantation, hair growth, neuropathic pain, lung fibrosis and colon cancer. Most of these functions are mediated by G protein-coupled receptors (GPCRs) specific to LPA. So far, six GPCRs for LPA have been identified: LPA(1)/Edg2, LPA(2)/Edg4, LPA(3)/Edg7, LPA(4)/GPR23/P2Y9, LPA(5)/GPR92 and LPA(6)/P2Y5. An intracellular target of LPA has also been proposed. Among the LPA receptors, LPA(3) is unique in that it is activated significantly by a specific form of LPA (2-acyl LPA with unsaturated fatty acids) and is expressed in a limited number of tissues such as the reproductive organs. Recent studies have shown that LPA(3)-mediated LPA signaling is essential for proper embryo implantation and have revealed an unexpected genetic linkage between LPA and prostaglandin signaling. Here we review recent advances in the study of LPA(3), especially studies using LPA(3)-deficient mice. In addition, we focus on the agonists and antagonists that are specific to each LPA receptor as important tools for the functional study of LPA signaling.
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Affiliation(s)
- Kotaro Hama
- Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, Japan
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372
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Abstract
OBJECTIVE For several chronic inflammatory disease states, therapy is enhanced by improving the pharmacokinetic properties of anti-inflammatory drugs through conjugation with polyethylene glycol. We hypothesized that part of the beneficial action of PEGylated drugs may be derived from the anti-inflammatory properties of polyethylene glycol (PEG) itself. DESIGN Randomized, double-blinded, controlled ex vivo and in vivo laboratory studies. SETTING University research laboratories. SUBJECTS Human neutrophils and mononuclear cells, macrophage cell line, and adult rats and mice. INTERVENTIONS The effect of PEG (either low-molecular-weight [200-400] or high-molecular-weight [>4000]) was assessed on survival after systemic inflammation induced by lipopolysaccharide or zymosan. The effects of PEG on zymosan, lipopolysaccharide, or streptolysin-induced inflammatory and bioenergetic responses of immune cells were also assessed. MEASUREMENTS AND MAIN RESULTS Low-molecular-weight PEG reduced inflammatory cytokine expression, pyrexia, and mortality by >50% in both lipopolysaccharide and zymosan models of sepsis. Low-molecular-weight PEG reduced cytokine expression both in vivo and in vitro, and attenuated activation of human neutrophils in response to lipopolysaccharide or zymosan. By contrast, high-molecular-weight PEG conferred less significant survival effects after lipopolysaccharide and zymosan, and it did not exhibit such profound anti-inflammatory effects. Low-molecular-weight PEG attenuated lipopolysaccharide-induced activation of pro-apoptotic pathways (lysophosphatidic acid receptor and caspase-domain signaling) in the livers of endotoxemic rats. Streptolysin-induced necrosis of human neutrophils was reduced by low-molecular-weight PEG, indicating a mechanism that involves coating and/or stabilizing the cellular membrane. Low-molecular-weight PEG preserved human neutrophil responses to septic serum and bioenergetic function in macrophages and neutrophils. CONCLUSION PEG is a commonly used, safe, nonimmunogenic molecule possessing hitherto unappreciated anti-inflammatory properties. Low-molecular-weight PEG may potentially play a role in the therapy of systemic inflammation and sepsis.
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373
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Birgbauer E, Chun J. Lysophospholipid receptors LPA 1-3 are not required for the inhibitory effects of LPA on mouse retinal growth cones. Eye Brain 2010; 2:1-13. [PMID: 26966392 DOI: 10.2147/eb.s7666] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
One of the major requirements in the development of the visual system is axonal guidance of retinal ganglion cells toward correct targets in the brain. A novel class of extracellular lipid signaling molecules, lysophospholipids, may serve as potential axon guidance cues. They signal through cognate G protein-coupled receptors, at least some of which are expressed in the visual system. Here we show that in the mouse visual system, a lysophospholipid known as lysophosphatidic acid (LPA) is inhibitory to retinal neurites in vitro when delivered extracellularly, causing growth cone collapse and neurite retraction. This inhibitory effect of LPA is both active in the nanomolar range and specific compared to the related lysophospholipid, sphingosine 1-phosphate (S1P). Knockout mice lacking three of the five known LPA receptors, LPA1-3, continue to display retinal growth cone collapse and neurite retraction in response to LPA, demonstrating that these three receptors are not required for these inhibitory effects and indicating the existence of one or more functional LPA receptors expressed on mouse retinal neurites that can mediate neurite retraction.
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Affiliation(s)
- Eric Birgbauer
- Department of Molecular Biology, Helen L Dorris Institute for Neurological and Psychiatric Disorders, The Scripps Research Institute, La Jolla, CA, USA
| | - Jerold Chun
- Department of Molecular Biology, Helen L Dorris Institute for Neurological and Psychiatric Disorders, The Scripps Research Institute, La Jolla, CA, USA
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374
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Fletcher JI, Haber M, Henderson MJ, Norris MD. ABC transporters in cancer: more than just drug efflux pumps. Nat Rev Cancer 2010; 10:147-56. [PMID: 20075923 DOI: 10.1038/nrc2789] [Citation(s) in RCA: 769] [Impact Index Per Article: 54.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Multidrug transporter proteins are best known for their contributions to chemoresistance through the efflux of anticancer drugs from cancer cells. However, a considerable body of evidence also points to their importance in cancer extending beyond drug transport to fundamental roles in tumour biology. Currently, much of the evidence for these additional roles is correlative and definitive studies are needed to confirm causality. We propose that delineating the precise roles of these transporters in tumorigenesis and treatment response will be important for the development of more effective targeted therapies.
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Affiliation(s)
- Jamie I Fletcher
- Children's Cancer Institute Australia for Medical Research, Lowry Cancer Research Centre, University of New South Wales, P.O. BOX 151, Randwick NSW 2031, Australia
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375
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Aydin M, Downing K, Villegas G, Zhang X, Chua R, Melman A, DiSanto ME. The sphingosine-1-phosphate pathway is upregulated in response to partial urethral obstruction in male rats and activates RhoA/Rho-kinase signalling. BJU Int 2010; 106:562-71. [DOI: 10.1111/j.1464-410x.2009.09156.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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376
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Fotopoulou S, Oikonomou N, Grigorieva E, Nikitopoulou I, Paparountas T, Thanassopoulou A, Zhao Z, Xu Y, Kontoyiannis DL, Remboutsika E, Aidinis V. ATX expression and LPA signalling are vital for the development of the nervous system. Dev Biol 2010; 339:451-64. [PMID: 20079728 DOI: 10.1016/j.ydbio.2010.01.007] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2009] [Revised: 01/04/2010] [Accepted: 01/05/2010] [Indexed: 02/07/2023]
Abstract
Autotaxin (ATX) is a secreted glycoprotein widely present in biological fluids, originally isolated from the supernatant of melanoma cells as an autocrine motility stimulation factor. Its enzymatic product, lysophosphatidic acid (LPA), is a phospholipid mediator that evokes growth-factor-like responses in almost all cell types through G-protein coupled receptors. To assess the role of ATX and LPA signalling in pathophysiology, a conditional knockout mouse was created. Ubiquitous, obligatory deletion resulted to embryonic lethality most likely due to aberrant vascular branching morphogenesis and chorio-allantoic fusion. Moreover, the observed phenotype was shown to be entirely depended on embryonic, but not extraembryonic or maternal ATX expression. In addition, E9.5 ATX null mutants exhibited a failure of neural tube closure, most likely independent of the circulatory failure, which correlated with decreased cell proliferation and increased cell death. More importantly, neurite outgrowth in embryo explants was severely compromised in mutant embryos but could be rescued upon the addition of LPA, thus confirming a role for ATX and LPA signalling in the development of the nervous system. Finally, expression profiling of mutant embryos revealed attenuated embryonic expression of HIF-1a in the absence of ATX, suggesting a novel effector pathway of ATX/LPA.
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Affiliation(s)
- Stella Fotopoulou
- Institute of Immunology, Biomedical Sciences Research Center Alexander Fleming, 16672 Athens, Greece
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377
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Shea BS, Brooks SF, Fontaine BA, Chun J, Luster AD, Tager AM. Prolonged exposure to sphingosine 1-phosphate receptor-1 agonists exacerbates vascular leak, fibrosis, and mortality after lung injury. Am J Respir Cell Mol Biol 2010; 43:662-73. [PMID: 20081052 DOI: 10.1165/rcmb.2009-0345oc] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Sphingosine 1-phosphate (S1P) is a key endogenous regulator of the response to lung injury, maintaining endothelial barrier integrity through interaction with one of its receptors, S1P(1). The short-term administration of S1P or S1P(1) receptor agonists enhances endothelial monolayer barrier function in vitro, and attenuates injury-induced vascular leak in the lung and other organ systems in vivo. Although S1P(1) agonists bind to and activate S1P(1), several of these agents also induce receptor internalization and degradation, and may therefore act as functional antagonists of S1P(1) after extended exposure. Here we report on the effects of prolonged exposure to these agents in bleomycin-induced lung injury. We demonstrate that repeated administration of S1P(1) agonists dramatically worsened lung injury after bleomycin challenge, as manifested by increased vascular leak and mortality. Consistent with these results, prolonged exposure to S1P(1) agonists in vitro eliminated the ability of endothelial cell monolayers to respond appropriately to the barrier-protective effects of S1P, indicating a loss of normal S1P-S1P(1) signaling. As bleomycin-induced lung injury progressed, continued exposure to S1P(1) agonists also resulted in increased pulmonary fibrosis. These data indicate that S1P(1) agonists can act as functional antagonists of S1P(1) on endothelial cells in vivo, which should be considered in developing these agents as therapies for vascular leak syndromes. Our findings also support the hypothesis that vascular leak is an important component of the fibrogenic response to lung injury, and suggest that targeting the S1P-S1P(1) pathway may also be an effective therapeutic strategy for fibrotic lung diseases.
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Affiliation(s)
- Barry S Shea
- Pulmonary and Critical Care Unit, Center for Immunology and Inflammatory Diseases, Massachusetts General Hospital, 149 13th Street, Charlestown, MA 02129, USA
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378
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Du W, Takuwa N, Yoshioka K, Okamoto Y, Gonda K, Sugihara K, Fukamizu A, Asano M, Takuwa Y. S1P(2), the G protein-coupled receptor for sphingosine-1-phosphate, negatively regulates tumor angiogenesis and tumor growth in vivo in mice. Cancer Res 2010; 70:772-81. [PMID: 20068174 DOI: 10.1158/0008-5472.can-09-2722] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Sphingosine-1-phosphate (S1P) has been implicated in tumor angiogenesis by acting through the G(i)-coupled chemotactic receptor S1P(1). Here, we report that the distinct receptor S1P(2) is responsible for mediating the G(12/13)/Rho-dependent inhibitory effects of S1P on Akt, Rac, and cell migration, thereby negatively regulating tumor angiogenesis and tumor growth. By using S1P(2)(LacZ/+) mice, we found that S1P(2) was expressed in both tumor and normal blood vessels in many organs, in both endothelial cells (EC) and vascular smooth muscle cells, as well as in tumor-associated, CD11b-positive bone marrow-derived cells (BMDC). Lewis lung carcinoma or B16 melanoma cells implanted in S1P(2)-deficient (S1P(2)(-/-)) mice displayed accelerated tumor growth and angiogenesis with enhanced association of vascular smooth muscle cells and pericytes. S1P(2)(-/-) ECs exhibited enhanced Rac activity, Akt phosphorylation, cell migration, proliferation, and tube formation in vitro. Coinjection of S1P(2)(-/-) ECs and tumor cells into wild-type mice also produced a relative enhancement of tumor growth and angiogenesis in vivo. S1P(2)(-/-) mice were also more efficient at recruiting CD11b-positive BMDCs into tumors compared with wild-type siblings. Bone marrow chimera experiments revealed that S1P(2) acted in BMDCs to promote tumor growth and angiogenesis. Our results indicate that, in contrast to endothelial S1P(1), which stimulates tumor angiogenesis, S1P(2) on ECs and BMDCs mediates a potent inhibition of tumor angiogenesis, suggesting a novel therapeutic tactic for anticancer treatment.
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Affiliation(s)
- Wa Du
- Department of Physiology, Kanazawa University Graduate School of Medicine, Kanazawa 920-8640, Japan
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379
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Imasawa T, Koike K, Ishii I, Chun J, Yatomi Y. Blockade of sphingosine 1-phosphate receptor 2 signaling attenuates streptozotocin-induced apoptosis of pancreatic beta-cells. Biochem Biophys Res Commun 2010; 392:207-11. [PMID: 20060809 DOI: 10.1016/j.bbrc.2010.01.016] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Accepted: 01/06/2010] [Indexed: 12/31/2022]
Abstract
Sphingosine 1-phosphate (S1P) is a potent sphingolipid mediator that acts through five cognate G protein-coupled receptors (S1P(1)-S1P(5)) and regulates many critical biological processes. Recent studies indicated that S1P at nanomolar concentrations significantly reduces cytokine-induced apoptosis of pancreatic beta-cells in which genes for S1P(1)-S1P(4) are co-expressed. However, the S1P receptor subtype(s) involved in this effect remains to be clarified. In this study, we investigated the potential role of S1P(2) in streptozotocin (STZ)-induced apoptosis of pancreatic beta-cells and progression of diabetes. S1P(2)-deficient (S1P(2)(-/-)) mice displayed a greater survive ability, lower blood glucose levels, and smaller numbers of TUNEL-positive apoptotic beta-cells to administration of a high dose of STZ than wild-type (WT) mice. S1P(2)(-/-) mice showed higher insulin/glucose ratios (an index of relative insulin deficiency) and larger insulin-positive islet areas to administration of a low dose of STZ than WT mice. Moreover, administration of JTE-013, a S1P(2)-specific antagonist, to WT mice ameliorated STZ-induced blood glucose elevation and reduced the incidence of diabetes. Our findings indicate that blockade of S1P(2) signaling attenuates STZ-induced apoptosis of pancreatic beta-cells and decreases the incidence of diabetes.
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Affiliation(s)
- Toshiyuki Imasawa
- Department of Internal Medicine, Division of Immunopathology, Clinical Research Center, Chiba-East National Hospital, 673 Nitona, Chuoh, Chiba 260-8712, Japan.
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380
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Tao R, Hoover HE, Honbo N, Kalinowski M, Alano CC, Karliner JS, Raffai R. High-density lipoprotein determines adult mouse cardiomyocyte fate after hypoxia-reoxygenation through lipoprotein-associated sphingosine 1-phosphate. Am J Physiol Heart Circ Physiol 2010; 298:H1022-8. [PMID: 20061542 DOI: 10.1152/ajpheart.00902.2009] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The lipid mediator sphingosine 1-phosphate (S1P) confers survival benefits in cardiomyocytes and isolated hearts subjected to oxidative stress. High-density lipoprotein (HDL) is a major carrier of S1P in the serum, but whether HDL-associated S1P directly mediates survival in a preparation composed exclusively of cardiomyocytes has not been demonstrated. Accordingly, we tested the hypothesis that signal activation and survival during simulated ischemia-reperfusion injury in response to HDL require lipoprotein-associated S1P. As a model, we used adult mouse cardiomyocytes subjected to hypoxia-reoxygenation. Cells were treated or not with autologous mouse HDL, which significantly increased myocyte viability as measured by trypan blue exclusion. This survival effect was abrogated by the S1P(1) and SIP(3) receptor antagonist VPC 23019. The selective S1P(3) antagonist CAY10444, the G(i) antagonist pertussis toxin, the MEK (MAPK/ERK) kinase inhibitor PD-98059, and the phosphoinositide-3 kinase inhibitor wortmannin also inhibited the prosurvival effect of HDL. We observed that HDL activated both Akt (protein kinase B) and the MEK1/2-ERK1/2 pathway and also stimulated phosphorylation of glycogen synthase kinase-3beta. ERK1/2 activation was through an S1P(1) subtype receptor-G(i) protein-dependent pathway, whereas the activation of Akt was inhibited by CAY10444, indicating mediation by S1P(3) subtype receptors. We conclude that HDL, via its cargo of S1P, can directly protect cardiomyocytes against simulated oxidative injury in the absence of vascular effects and that prosurvival signal activation is dependent on both S1P(1) and S1P(3) subtype receptors.
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Affiliation(s)
- Rong Tao
- Veterans Affairs Medical Center and Department of Medicine, University of California, San Francisco, USA
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381
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Ye X, Chun J. Lysophosphatidic acid (LPA) signaling in vertebrate reproduction. Trends Endocrinol Metab 2010; 21:17-24. [PMID: 19836970 PMCID: PMC2818173 DOI: 10.1016/j.tem.2009.08.003] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Revised: 08/03/2009] [Accepted: 08/04/2009] [Indexed: 12/28/2022]
Abstract
Lysophosphatidic acid (LPA) is a cell membrane phospholipid metabolite that can act as an extracellular signal. Its effects are mediated through at least five G protein-coupled receptors, LPA(1-5), and probably others as well. Studies in multiple species including LPAR-deficient mice and humans have identified or implicated important roles for receptor-mediated LPA signaling in multiple aspects of vertebrate reproduction. These include ovarian function, spermatogenesis, fertilization, early embryo development, embryo implantation, embryo spacing, decidualization, pregnancy maintenance and parturition. LPA signaling can also have pathological consequences, influencing aspects of endometriosis and ovarian cancer. Here we review recent progress in LPA signaling research relevant to female and male reproduction.
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Affiliation(s)
- Xiaoqin Ye
- Department of Physiology and Pharmacology, College of Veterinary Medicine, and Interdisciplinary Toxicology Program, University of Georgia, Athens, GA 30602, USA
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382
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Greco E, Santucci MB, Sali M, De Angelis FR, Papi M, De Spirito M, Delogu G, Colizzi V, Fraziano M. Natural lysophospholipids reduce Mycobacterium tuberculosis-induced cytotoxicity and induce anti-mycobacterial activity by a phagolysosome maturation-dependent mechanism in A549 type II alveolar epithelial cells. Immunology 2010; 129:125-32. [PMID: 19878354 PMCID: PMC2807493 DOI: 10.1111/j.1365-2567.2009.03145.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 05/26/2009] [Accepted: 06/10/2009] [Indexed: 01/15/2023] Open
Abstract
Human alveolar epithelial cells actively contribute to the innate immune response in the lung and play an important role in mycobacterial dissemination during primary infection, by undergoing cell death and by releasing mycobacteria. In the present study, we report that natural lysophospholipids, such as lysophosphatidic acid or sphingosine 1-phosphate, reduce Mycobacterium tuberculosis-induced cytotoxicity and enhance anti-mycobacterial activity in the A549 cell line, used as a model of type II alveolar epithelial cells. Intracellular mycobacterial killing was strictly dependent on phagolysosome maturation, which in turn was promoted by the activation of a Ca(2+)dependent phospholipase D. Finally, the restriction of mycobacteria in highly microbiocidal compartments was associated, in vitro, with a significant decrease in mycobacterial dissemination to macrophages. Taken as whole, these results suggest that the pulmonary lysophospholipid microenvironment may play a protective role during the early phases of host-pathogen interaction by enhancing anti-mycobacterial activity in type II alveolar epithelial cells.
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Affiliation(s)
- Emanuela Greco
- Department of Biology, University of Rome Tor Vergata, Rome, Italy
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383
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Unrestricted somatic stem cells from human umbilical cord blood grow in serum-free medium as spheres. BMC Biotechnol 2009; 9:101. [PMID: 20003538 PMCID: PMC2805630 DOI: 10.1186/1472-6750-9-101] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Accepted: 12/15/2009] [Indexed: 12/03/2022] Open
Abstract
Background Human umbilical cord blood-derived unrestricted somatic stem cells (USSCs), which are capable of multilineage differentiation, are currently under investigation for a number of therapeutic applications. A major obstacle to their clinical use is the fact that in vitro expansion is still dependent upon fetal calf serum, which could be a source of pathogens. In this study, we investigate the capacity of three different stem cell culture media to support USSCs in serum-free conditions; HEScGRO™, PSM and USSC growth mediumACF. Our findings demonstrate that USSCs do not grow in HEScGRO™ or PSM, but we were able to isolate, proliferate and maintain multipotency of three USSC lines in USSC growth mediumACF. Results For the first one to three passages, cells grown in USSC growth mediumACF proliferate and maintain their morphology, but with continued passaging the cells form spherical cell aggregates. Upon dissociation of spheres, cells continue to grow in suspension and form new spheres. Dissociated cells can also revert to monolayer growth when cultured on extracellular matrix support (fibronectin or gelatin), or in medium containing fetal calf serum. Analysis of markers associated with pluripotency (Oct4 and Sox2) and differentiation (FoxA2, Brachyury, Goosecoid, Nestin, Pax6, Gata6 and Cytokeratin 8) confirms that cells in the spheres maintain their gene expression profile. The cells in the spheres also retain the ability to differentiate in vitro to form cells representative of the three germline layers after five passages. Conclusions These data suggest that USSC growth mediumACF maintains USSCs in an undifferentiated state and supports growth in suspension. This is the first demonstration that USSCs can grow in a serum- and animal component-free medium and that USSCs can form spheres.
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384
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Murakami N, Hashidate T, Harayama T, Yokomizo T, Shimizu T, Nakamura M. Transcriptional regulation of human G2A in monocytes/ macrophages: involvement of c/EBPs, Runx and Pu.1. Genes Cells 2009; 14:1441-55. [DOI: 10.1111/j.1365-2443.2009.01360.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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385
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Sun H, Ren J, Zhu Q, Kong FZ, Wu L, Pan BR. Effects of lysophosphatidic acid on human colon cancer cells and its mechanisms of action. World J Gastroenterol 2009; 15:4547-55. [PMID: 19777613 PMCID: PMC2751999 DOI: 10.3748/wjg.15.4547] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To study the effects of lysophosphatidic acid (LPA) on proliferation, adhesion, migration, and apoptosis in the human colon cancer cell line, SW480, and its mechanisms of action.
METHODS: Methyl tetrazolium assay was used to assess cell proliferation. Flow cytometry was employed to detect cell apoptosis. Cell migration was measured by using a Boyden transwell migration chamber. Cell adhesion assay was performed in 96-well plates according to protocol.
RESULTS: LPA significantly stimulated SW480 cell proliferation in a dose-dependent and time-dependent manner compared with the control group (P < 0.05) while the mitogen-activated protein kinase (MAPK) inhibitor, PD98059, significantly blocked the LPA stimulation effect on proliferation. LPA also significantly stimulated adhesion and migration of SW480 cells in a dose-dependent manner (P < 0.05). Rho kinase inhibitor, Y-27632, significantly inhibited the up-regulatory effect of LPA on adhesion and migration (P < 0.05). LPA significantly protected cells from apoptosis induced by the chemotherapeutic drugs, cisplatin and 5-FU (P < 0.05), but the phosphoinositide 3-kinase (PI3K) inhibitor, LY294002, significantly blocked the protective effect of LPA on apoptosis.
CONCLUSION: LPA stimulated proliferation, adhesion, migration of SW480 cells, and protected from apoptosis. The Ras/Raf-MAPK, G12/13-Rho-RhoA and PI3K-AKT/PKB signal pathways may be involved.
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386
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Takuwa N, Ohkura SI, Takashima SI, Ohtani K, Okamoto Y, Tanaka T, Hirano K, Usui S, Wang F, Du W, Yoshioka K, Banno Y, Sasaki M, Ichi I, Okamura M, Sugimoto N, Mizugishi K, Nakanuma Y, Ishii I, Takamura M, Kaneko S, Kojo S, Satouchi K, Mitumori K, Chun J, Takuwa Y. S1P3-mediated cardiac fibrosis in sphingosine kinase 1 transgenic mice involves reactive oxygen species. Cardiovasc Res 2009; 85:484-93. [PMID: 19755413 DOI: 10.1093/cvr/cvp312] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS Sphingosine kinase 1 (SPHK1), its product sphingosine-1-phosphate (S1P), and S1P receptor subtypes have been suggested to play protective roles for cardiomyocytes in animal models of ischaemic preconditioning and cardiac ischaemia/reperfusion injury. To get more insight into roles for SPHK1 in vivo, we have generated SPHK1-transgenic (TG) mice and analysed the cardiac phenotype. METHODS AND RESULTS SPHK1-TG mice overexpressed SPHK1 in diverse tissues, with a nearly 20-fold increase in enzymatic activity. The TG mice grew normally with normal blood chemistry, cell counts, heart rate, and blood pressure. Unexpectedly, TG mice with high but not low expression levels of SPHK1 developed progressive myocardial degeneration and fibrosis, with upregulation of embryonic genes, elevated RhoA and Rac1 activity, stimulation of Smad3 phosphorylation, and increased levels of oxidative stress markers. Treatment of juvenile TG mice with pitavastatin, an established inhibitor of the Rho family G proteins, or deletion of S1P3, a major myocardial S1P receptor subtype that couples to Rho GTPases and transactivates Smad signalling, both inhibited cardiac fibrosis with concomitant inhibition of SPHK1-dependent Smad-3 phosphorylation. In addition, the anti-oxidant N-2-mercaptopropyonylglycine, which reduces reactive oxygen species (ROS), also inhibited cardiac fibrosis. In in vivo ischaemia/reperfusion injury, the size of myocardial infarct was 30% decreased in SPHK1-TG mice compared with wild-type mice. CONCLUSION These results suggest that chronic activation of SPHK1-S1P signalling results in both pathological cardiac remodelling through ROS mediated by S1P3 and favourable cardioprotective effects.
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Affiliation(s)
- Noriko Takuwa
- Department of Physiology, Kanazawa University Graduate School of Medicine, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8640, Japan
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387
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Structural basis of transport of lysophospholipids by human serum albumin. Biochem J 2009; 423:23-30. [PMID: 19601929 DOI: 10.1042/bj20090913] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Lysophospholipids play important roles in cellular signal transduction and are implicated in many biological processes, including tumorigenesis, angiogenesis, immunity, atherosclerosis, arteriosclerosis, cancer and neuronal survival. The intracellular transport of lysophospholipids is through FA (fatty acid)-binding protein. Lysophospholipids are also found in the extracellular space. However, the transport mechanism of lysophospholipids in the extracellular space is unknown. HSA (human serum albumin) is the most abundant carrier protein in blood plasma and plays an important role in determining the absorption, distribution, metabolism and excretion of drugs. In the present study, LPE (lysophosphatidylethanolamine) was used as the ligand to analyse the interaction of lysophospholipids with HSA by fluorescence quenching and crystallography. Fluorescence measurement showed that LPE binds to HSA with a Kd (dissociation constant) of 5.6 microM. The presence of FA (myristate) decreases this binding affinity (Kd of 12.9 microM). Moreover, we determined the crystal structure of HSA in complex with both myristate and LPE and showed that LPE binds at Sudlow site I located in subdomain IIA. LPE occupies two of the three subsites in Sudlow site I, with the LPE acyl chain occupying the hydrophobic bottom of Sudlow site I and the polar head group located at Sudlow site I entrance region pointing to the solvent. This orientation of LPE in HSA suggests that HSA is capable of accommodating other lysophospholipids and phospholipids. The study provides structural information on HSA-lysophospholipid interaction and may facilitate our understanding of the transport and distribution of lysophospholipids.
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388
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Signaling pathways involved in DNA synthesis and migration in response to lysophosphatidic acid and low-density lipoprotein in coronary artery smooth muscle cells. Vascul Pharmacol 2009; 50:178-84. [PMID: 19563736 DOI: 10.1016/j.vph.2009.01.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 01/15/2009] [Accepted: 01/21/2009] [Indexed: 01/09/2023]
Abstract
Low-density lipoprotein (LDL) and lysophosphatidic acid (LPA), one of the lipid components of lipoprotein, induced the DNA synthesis of coronary artery smooth muscle cells (CASMCs). The LDL- and LPA-induced DNA synthesis was markedly inhibited by the LPA receptor antagonist Ki16425, pertussis toxin, small interfering RNAs targeted for LPA1 receptors, and a potent calcineurin inhibitor cyclosporine A. It has been reported that LDL and LPA induced a migration response in a manner sensitive to Ki16425, pertussis toxin, and a LPA1 receptor-specific small interfering RNA. However, cyclosporine A was ineffective in inhibiting the migration response. Instead, an epidermal growth factor (EGF) receptor tyrosine kinase inhibitor markedly suppressed the migration response to LDL and LPA without having any significant effect on DNA synthesis. Thus, the LDL-induced stimulation of DNA synthesis and migration in CASMCs is mediated by its component LPA through LPA1 receptors and G(i/o)-proteins. Ca2+/calcineurin pathways and transactivation of EGF receptors mediate LPA1-receptor-induced DNA synthesis and migration, respectively.
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389
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Ishii S, Noguchi K, Yanagida K. Non-Edg family lysophosphatidic acid (LPA) receptors. Prostaglandins Other Lipid Mediat 2009; 89:57-65. [DOI: 10.1016/j.prostaglandins.2009.06.001] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2009] [Accepted: 06/03/2009] [Indexed: 12/23/2022]
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390
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Sarai K, Shikata K, Shikata Y, Omori K, Watanabe N, Sasaki M, Nishishita S, Wada J, Goda N, Kataoka N, Makino H. Endothelial barrier protection by FTY720 under hyperglycemic condition: involvement of focal adhesion kinase, small GTPases, and adherens junction proteins. Am J Physiol Cell Physiol 2009; 297:C945-54. [PMID: 19657053 DOI: 10.1152/ajpcell.00606.2008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Recently, sphingosine 1-phosphate (S1P) has been highlighted as an endothelial barrier-stabilizing mediator. FTY720 is a S1P analog originally developed as a novel immunosuppressant. The phosphorylated form of FTY720 binds to S1P receptors to exert S1P-like biological effects, suggesting endothelial barrier promotion by FTY720. To elucidate whether FTY720 induces signaling events related to endothelial barrier enhancement under hyperglycemic conditions, human microvascular endothelial cells (HMVECs) preincubated with hyperglycemic (30 mM) medium were treated with 100 nM FTY720 for 3 h. Immunofluorescent microscopy and coprecipitation study revealed FTY720-induced focal adhesion kinase (FAK)-associated adherens junction (AJ) assembly at cell-cell contacts coincident with formation of a prominent cortical actin ring. FTY720 also induced transmonolayer electrical resistance (TER) augmentation in HMVEC monolayers in both normoglycemic and hyperglycemic conditions, implying endothelial barrier enhancement. Similar to S1P, site-specific FAK tyrosine phosphorylation analysis revealed FTY720-induced FAK [Y576] phosphorylation without phosphorylation of FAK [Y397/Y925]. Furthermore, FTY720 conditioned the phosphorylation profile of FAK [Y397/Y576/Y925] in hyperglycemic medium to the same pattern observed in normoglycemic medium. FTY720 challenge resulted in small GTPase Rac activation under hyperglycemic conditions, whereas increased Rho activity in hyperglycemic medium was restored to the basal level. Rac protein depletion by small interfering RNA (siRNA) technique completely abolished FTY720-induced FAK [Y576] phosphorylation. These findings strongly suggest the barrier protective effect of FTY720 on HMVEC monolayers in hyperglycemic medium via S1P signaling, further implying the possibility of FTY720 as a therapeutic agent of diabetic vascular disorder.
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Affiliation(s)
- Kei Sarai
- Department of Medicine and Clinical Science, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan.
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391
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Kim CH. Reining in FoxP3
+
regulatory T cells by the sphingosine 1‐phosphate‐S1P1 axis. Immunol Cell Biol 2009; 87:502-4. [DOI: 10.1038/icb.2009.49] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Chang H Kim
- Laboratory of Immunology and Hematopoiesis, Department of Comparative Pathobiology, Purdue Cancer Center, Purdue University West Lafayette 725 Harrison Street IN 47907 USA
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392
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Santin LJ, Bilbao A, Pedraza C, Matas-Rico E, López-Barroso D, Castilla-Ortega E, Sánchez-López J, Riquelme R, Varela-Nieto I, de la Villa P, Suardíaz M, Chun J, De Fonseca FR, Estivill-Torrús G. Behavioral phenotype of maLPA1-null mice: increased anxiety-like behavior and spatial memory deficits. GENES BRAIN AND BEHAVIOR 2009; 8:772-84. [PMID: 19689455 DOI: 10.1111/j.1601-183x.2009.00524.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Lysophosphatidic acid (LPA) has emerged as a new regulatory molecule in the brain. Recently, some studies have shown a role for this molecule and its LPA(1) receptor in the regulation of plasticity and neurogenesis in the adult brain. However, no systematic studies have been conducted to investigate whether the LPA(1) receptor is involved in behavior. In this study, we studied the phenotype of maLPA(1)-null mice, which bear a targeted deletion at the lpa(1) locus, in a battery of tests examining neurologic performance, habituation in exploratory behavior in response to low and mild anxiety environments and spatial memory. MaLPA(1)-null mutants showed deficits in both olfaction and somesthesis, but not in retinal or auditory functions. Sensorimotor co-ordination was impaired only in the equilibrium and grasping reflexes. The mice also showed impairments in neuromuscular strength and analgesic response. No additional differences were observed in the rest of the tests used to study sensoriomotor orientation, limb reflexes and co-ordinated limb use. At behavioral level, maLPA(1)-null mice showed an impaired exploration in the open field and increased anxiety-like response when exposed to the elevated plus maze. Furthermore, the mice exhibit impaired spatial memory retention and reduced use of spatial strategies in the Morris water maze. We propose that the LPA(1) receptor may play a major role in both spatial memory and response to anxiety-like conditions.
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Affiliation(s)
- L J Santin
- Departamento de Psicobiologíay Metodología de las CC, Universidad de Málaga, Málaga, Spain.
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393
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Grabski AD, Shimizu T, Deou J, Mahoney WM, Reidy MA, Daum G. Sphingosine-1-phosphate receptor-2 regulates expression of smooth muscle alpha-actin after arterial injury. Arterioscler Thromb Vasc Biol 2009; 29:1644-50. [PMID: 19608972 DOI: 10.1161/atvbaha.109.191965] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE This study tests the hypothesis that S1P2R regulates expression of SMC differentiation genes after arterial injury. METHODS AND RESULTS Carotid ligation injury was performed in wild-type and S1P2R-null mice. At various time points after injury, expression of multiple SMC differentiation genes, myocardin, and S1P receptors (S1P1R, S1P2R, and S1P3R) was measured by quantitative PCR. These experiments demonstrate that at day 7 after injury, S1P2R specifically regulates expression of smooth muscle alpha-actin (SMA) and that this is not mediated by changes in expression of myocardin or any of the S1PRs. In vitro studies using carotid SMCs prepared from wild-type and S1P2R-null mice show that S1P stimulates expression of all SMC-differentiation genes tested, but S1P2R significantly regulates expression of SMA and SM22 alpha only. Chromatin immunoprecipitation assays suggest that S1P-induced recruitment of serum response factor to the SMA promoter and enhancer largely depends on S1P2R. S1P-stimulated SMA expression requires S1P2R-dependent activation of RhoA and mobilization of calcium from intracellular stores. Chelation of calcium does not affect the activation of RhoA by S1P, whereas blockade of Rho by C3 exotoxin partially inhibits the mobilization of calcium by S1P. CONCLUSIONS The results of this study support the hypothesis that S1P2R regulates expression of SMA after injury. We further conclude that transcriptional regulation of SMA by S1P in vitro requires S1P2R-dependent activation of RhoA and mobilization of calcium from intracellular calcium stores.
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Affiliation(s)
- Allison D Grabski
- University of Washington, Department of Surgery, 815 Mercer Street, Seattle, WA 98109, USA
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394
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Meng H, Lee VM. Differential expression of sphingosine-1-phosphate receptors 1-5 in the developing nervous system. Dev Dyn 2009; 238:487-500. [PMID: 19161225 DOI: 10.1002/dvdy.21852] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Sphingosine-1-phosphate (S1P) binds to G protein-coupled receptors and can regulate a wide range of cellular functions. In a previous study, we isolated two key enzymes in the S1P pathway that were expressed in migrating neural crest cells. To determine if S1P receptors are present in neural crest cells or peripheral nervous system, we examine the expression patterns of S1P receptors (S1pr1-5) in mouse, and s1pr1 and s1pr3 in chick embryos. Here, we present a comprehensive expression analysis of these receptors using in situ hybridizations, which provide spatiotemporal information. We showed that S1pr2 was expressed in migrating cranial neural crest cells and enteric neurons. S1pr1 was prominently expressed in the neuroepithelium whereas S1pr4 and S1pr5 were in neurons at later stages. On the contrary, S1pr3 was predominantly detected in non-neuronal cells within and surrounding neural structures. We also described novel expression sites for S1P receptors in the developing nervous system.
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Affiliation(s)
- H Meng
- Division of Developmental Biology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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395
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Liu G, Burns S, Huang G, Boyd K, Proia RL, Flavell RA, Chi H. The receptor S1P1 overrides regulatory T cell-mediated immune suppression through Akt-mTOR. Nat Immunol 2009; 10:769-77. [PMID: 19483717 PMCID: PMC2732340 DOI: 10.1038/ni.1743] [Citation(s) in RCA: 268] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Accepted: 04/21/2009] [Indexed: 12/14/2022]
Abstract
Regulatory T cells (Treg) are critically involved in maintaining immunological tolerance, but this potent suppression must be quenched to allow the generation of adaptive immune responses. Here we report that type 1 sphingosine-1-phosphate (S1P) receptor (S1P1) delivers an intrinsic negative signal to restrain thymic generation, peripheral maintenance and suppressive activity of Treg cells. Combining loss- and gain-of-function genetic approaches, we found that S1P1 blocked the differentiation of thymic Treg precursors and function of mature Treg cells, and affected Treg-mediated immune tolerance. S1P1 induced the selective activation of the Akt-mTOR pathway to impede Treg development and function. Dynamic regulation of S1P1 contributed to lymphocyte priming and immune homeostasis. Thus, by antagonizing Treg-mediated immune suppression, the lipid-activated S1P1-Akt-mTOR pathway orchestrates adaptive immune responses.
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Affiliation(s)
- Guangwei Liu
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
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396
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Burnum KE, Cornett DS, Puolitaival SM, Milne SB, Myers DS, Tranguch S, Brown HA, Dey SK, Caprioli RM. Spatial and temporal alterations of phospholipids determined by mass spectrometry during mouse embryo implantation. J Lipid Res 2009; 50:2290-8. [PMID: 19429885 DOI: 10.1194/jlr.m900100-jlr200] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Molecular events involved in successful embryo implantation are not well understood. In this study, we used MALDI imaging mass spectrometry (IMS) technologies to characterize the spatial and temporal distribution of phospholipid species associated with mouse embryo implantation. Molecular images showing phospholipid distribution within implantation sites changed markedly between distinct cellular areas during days 4-8 of pregnancy. For example, by day 8, linoleate- and docosahexaenoate-containing phospholipids localized to regions destined to undergo cell death, whereas oleate-containing phospholipids localized to angiogenic regions. Arachidonate-containing phospholipids showed different segregation patterns depending on the lipid class, revealing a strong correlation of phosphatidylethanolamines and phosphatidylinositols with cytosolic phospholipase A(2alpha) and cyclooxygenase-2 during embryo implantation. LC-ESI-MS/MS was used to validate MALDI IMS phospholipid distribution patterns. Overall, molecular images revealed the dynamic complexity of lipid distributions in early pregnancy, signifying the importance of complex interplay of lipid molecules in uterine biology and implantation.
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Affiliation(s)
- Kristin E Burnum
- Departments of Biochemistry, Mass Spectrometry Research Center, Nashville, TN 37232, USA
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397
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Endo T, Kano K, Motoki R, Hama K, Okudaira S, Ishida M, Ogiso H, Tanaka M, Matsuki N, Taguchi R, Kanai M, Shibasaki M, Arai H, Aoki J. Lysophosphatidylmethanol is a pan lysophosphatidic acid receptor agonist and is produced by autotaxin in blood. ACTA ACUST UNITED AC 2009; 146:283-93. [DOI: 10.1093/jb/mvp068] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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398
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Shimizu T. Lipid mediators in health and disease: enzymes and receptors as therapeutic targets for the regulation of immunity and inflammation. Annu Rev Pharmacol Toxicol 2009; 49:123-50. [PMID: 18834304 DOI: 10.1146/annurev.pharmtox.011008.145616] [Citation(s) in RCA: 430] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Prostaglandins, leukotrienes, platelet-activating factor, lysophosphatidic acid, sphingosine 1-phosphate, and endocannabinoids, collectively referred to as lipid mediators, play pivotal roles in immune regulation and self-defense, and in the maintenance of homeostasis in living systems. They are produced by multistep enzymatic pathways, which are initiated by the de-esterification of membrane phospholipids by phospholipase A2s or sphingo-myelinase. Lipid mediators exert their biological effects by binding to cognate receptors, which are members of the G protein-coupled receptor superfamily. The synthesis of the lipid mediators and subsequent induction of receptor activity is tightly regulated under normal physiological conditions, and enzyme and/or receptor dysfunction can lead to a variety of disease conditions. Thus, the manipulation of lipid mediator signaling, through either enzyme inhibitors or receptor antagonists and agonists, has great potential as a therapeutic approach to disease. In this review, I summarize our current state of knowledge of the synthesis of lipid mediators and the function of their cognate receptors, and discuss the effects of genetic or pharmacological ablation of enzyme or receptor function on various pathophysiological processes.
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Affiliation(s)
- Takao Shimizu
- Department of Biochemistry and Molecular Biology, The University of Tokyo, Tokyo 113-0033, Japan.
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399
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Yanagida K, Masago K, Nakanishi H, Kihara Y, Hamano F, Tajima Y, Taguchi R, Shimizu T, Ishii S. Identification and characterization of a novel lysophosphatidic acid receptor, p2y5/LPA6. J Biol Chem 2009; 284:17731-41. [PMID: 19386608 DOI: 10.1074/jbc.m808506200] [Citation(s) in RCA: 195] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
p2y5 is an orphan G protein-coupled receptor that is closely related to the fourth lysophosphatidic acid (LPA) receptor, LPA4. Here we report that p2y5 is a novel LPA receptor coupling to the G13-Rho signaling pathway. "LPA receptor-null" RH7777 and B103 cells exogenously expressing p2y5 showed [3H]LPA binding, LPA-induced [35S]guanosine 5'-3-O-(thio)triphosphate binding, Rho-dependent alternation of cellular morphology, and Gs/13 chimeric protein-mediated cAMP accumulation. LPA-induced contraction of human umbilical vein endothelial cells was suppressed by small interfering RNA knockdown of endogenously expressed p2y5. We also found that 2-acyl-LPA had higher activity to p2y5 than 1-acyl-LPA. A recent study has suggested that p2y5 is an LPA receptor essential for human hair growth. We confirmed that p2y5 is a functional LPA receptor and propose to designate this receptor LPA6.
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Affiliation(s)
- Keisuke Yanagida
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Univerfsity of Tokyo, Tokyo, Japan
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400
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Karagiosis SA, Chrisler WB, Bollinger N, Karin NJ. Lysophosphatidic acid-induced ERK activation and chemotaxis in MC3T3-E1 preosteoblasts are independent of EGF receptor transactivation. J Cell Physiol 2009; 219:716-23. [PMID: 19189345 DOI: 10.1002/jcp.21720] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Bone-forming osteoblasts and their progenitors are target cells for the lipid growth factor lysophosphatidic acid (LPA) which is produced by degranulating platelets at sites of tissue injury. LPA is a potent inducer of bone cell chemotaxis, proliferation and survival in vitro, and this lipid factor is an attractive candidate to facilitate preosteoblast migration during skeletal regeneration in vivo. In this study we sought to more clearly define the intracellular signaling pathways mediating the effects of LPA on bone cells. LPA-treated MC3T3-E1 preosteoblastic cells exhibited a bimodal activation of extracellular signal-related kinase (ERK1/2) with maximal phosphorylation at 5 and 60 min. MEK1/2 activation was detected within 2.5 min of LPA exposure and remained elevated for at least an hour. ERK1/2 phosphorylation was not coupled to Ras activation or to LPA-induced elevations in cytosolic Ca(2+). While LPA exposure transactivates the EGF receptor in many cell types, LPA-stimulated ERK1/2 activation in MC3T3-E1 cells was unaffected by the inhibition of EGF receptor function. ERK isoforms can function as transcription factors and ERK1/2 rapidly accumulated in the nuclei of LPA-treated cells, a process that was blocked if ERK1/2 phosphorylation was prevented. Blocking ERK1/2 phosphorylation also led to significant decreases in LPA-induced MC3T3-E1 cell chemotaxis, while the inhibition of EGF receptor function had no effect on the stimulation of preosteoblast motility by LPA. Our results identify ERK1/2 activation as a mediator of LPA-stimulated MC3T3-E1 cell migration that may be relevant to preosteoblast motility and gene expression during bone repair in vivo. J. Cell. Physiol. 219: 716-723, 2009. (c) 2009 Wiley-Liss, Inc.
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Affiliation(s)
- Sue A Karagiosis
- Cell Biology and Biochemistry Group, Pacific Northwest National Laboratory, Richland, Washington
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