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Galvani S, Sanson M, Blaho VA, Swendeman SL, Obinata H, Conger H, Dahlbäck B, Kono M, Proia RL, Smith JD, Hla T. HDL-bound sphingosine 1-phosphate acts as a biased agonist for the endothelial cell receptor S1P1 to limit vascular inflammation. Sci Signal 2015; 8:ra79. [PMID: 26268607 PMCID: PMC4768813 DOI: 10.1126/scisignal.aaa2581] [Citation(s) in RCA: 227] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The sphingosine 1-phosphate receptor 1 (S1P1) is abundant in endothelial cells, where it regulates vascular development and microvascular barrier function. In investigating the role of endothelial cell S1P1 in adult mice, we found that the endothelial S1P1 signal was enhanced in regions of the arterial vasculature experiencing inflammation. The abundance of proinflammatory adhesion proteins, such as ICAM-1, was enhanced in mice with endothelial cell-specific deletion of S1pr1 and suppressed in mice with endothelial cell-specific overexpression of S1pr1, suggesting a protective function of S1P1 in vascular disease. The chaperones ApoM(+)HDL (HDL) or albumin bind to sphingosine 1-phosphate (S1P) in the circulation; therefore, we tested the effects of S1P bound to each chaperone on S1P1 signaling in cultured human umbilical vein endothelial cells (HUVECs). Exposure of HUVECs to ApoM(+)HDL-S1P, but not to albumin-S1P, promoted the formation of a cell surface S1P1-β-arrestin 2 complex and attenuated the ability of the proinflammatory cytokine TNFα to activate NF-κB and increase ICAM-1 abundance. Although S1P bound to either chaperone induced MAPK activation, albumin-S1P triggered greater Gi activation and receptor endocytosis. Endothelial cell-specific deletion of S1pr1 in the hypercholesterolemic Apoe(-/-) mouse model of atherosclerosis enhanced atherosclerotic lesion formation in the descending aorta. We propose that the ability of ApoM(+)HDL to act as a biased agonist on S1P1 inhibits vascular inflammation, which may partially explain the cardiovascular protective functions of HDL.
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Sun HL, Jiang T. The structure of nerve growth factor in complex with lysophosphatidylinositol. Acta Crystallogr F Struct Biol Commun 2015; 71:906-12. [PMID: 26144237 PMCID: PMC4498713 DOI: 10.1107/s2053230x15008870] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 05/06/2015] [Indexed: 01/19/2023] Open
Abstract
Nerve growth factor (NGF) is an important protein that is involved in a variety of physiological processes in cell survival, differentiation, proliferation and maintenance. The previously reported crystal structure of mouse NGF (mNGF) in complex with lysophosphatidylserine (LysoPS) showed that mNGF can bind LysoPS at its dimeric interface. To expand the understanding of the structural basis for specific lipid recognition by NGF, the crystal structure of mNGF complexed with lysophosphatidylinositol (13:0 LysoPI) was solved. Interestingly, in addition to Lys88, which interacts with the head glycerol group and the phosphate group of LysoPI, as seen in the mNGF-LysoPS structure, two additional residues, Tyr52 and Arg50, were found to assist in lipid binding by forming hydrogen bonds to the inositol moiety of the LysoPI molecule. The results suggest a specific recognition mechanism of inositol group-containing lipids by NGF, which may help in the design of bioactive compounds that can be delivered by NGF.
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St John AL, Ang WXG, Huang MN, Kunder CA, Chan EW, Gunn MD, Abraham SN. S1P-Dependent trafficking of intracellular yersinia pestis through lymph nodes establishes Buboes and systemic infection. Immunity 2014; 41:440-450. [PMID: 25238098 DOI: 10.1016/j.immuni.2014.07.013] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 07/14/2014] [Indexed: 11/19/2022]
Abstract
Pathologically swollen lymph nodes (LNs), or buboes, characterize Yersinia pestis infection, yet how they form and function is unknown. We report that colonization of the draining LN (dLN) occurred due to trafficking of infected dendritic cells and monocytes in temporally distinct waves in response to redundant chemotactic signals, including through CCR7, CCR2, and sphingosine-1-phospate (S1P) receptors. Retention of multiple subsets of phagocytes within peripheral LNs using the S1P receptor agonist FTY720 or S1P1-specific agonist SEW2871 increased survival, reduced colonization of downstream LNs, and limited progression to transmission-associated septicemic or pneumonic disease states. Conditional deletion of S1P1 in mononuclear phagocytes abolished node-to-node trafficking of infected cells. Thus, Y. pestis-orchestrated LN remodeling promoted its dissemination via host cells through the lymphatic system but can be blocked by prevention of leukocyte egress from DLNs. These findings define a novel trafficking route of mononuclear phagocytes and identify S1P as a therapeutic target during infection.
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Degagné E, Pandurangan A, Bandhuvula P, Kumar A, Eltanawy A, Zhang M, Yoshinaga Y, Nefedov M, de Jong PJ, Fong LG, Young SG, Bittman R, Ahmedi Y, Saba JD. Sphingosine-1-phosphate lyase downregulation promotes colon carcinogenesis through STAT3-activated microRNAs. J Clin Invest 2014; 124:5368-84. [PMID: 25347472 DOI: 10.1172/jci74188] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 09/25/2014] [Indexed: 12/11/2022] Open
Abstract
Growing evidence supports a link between inflammation and cancer; however, mediators of the transition between inflammation and carcinogenesis remain incompletely understood. Sphingosine-1-phosphate (S1P) lyase (SPL) irreversibly degrades the bioactive sphingolipid S1P and is highly expressed in enterocytes but downregulated in colon cancer. Here, we investigated the role of SPL in colitis-associated cancer (CAC). We generated mice with intestinal epithelium-specific Sgpl1 deletion and chemically induced colitis and tumor formation in these animals. Compared with control animals, mice lacking intestinal SPL exhibited greater disease activity, colon shortening, cytokine levels, S1P accumulation, tumors, STAT3 activation, STAT3-activated microRNAs (miRNAs), and suppression of miR-targeted anti-oncogene products. This phenotype was attenuated by STAT3 inhibition. In fibroblasts, silencing SPL promoted tumorigenic transformation through a pathway involving extracellular transport of S1P through S1P transporter spinster homolog 2 (SPNS2), S1P receptor activation, JAK2/STAT3-dependent miR-181b-1 induction, and silencing of miR-181b-1 target cylindromatosis (CYLD). Colon biopsies from patients with inflammatory bowel disease revealed enhanced S1P and STAT3 signaling. In mice with chemical-induced CAC, oral administration of plant-type sphingolipids called sphingadienes increased colonic SPL levels and reduced S1P levels, STAT3 signaling, cytokine levels, and tumorigenesis, indicating that SPL prevents transformation and carcinogenesis. Together, our results suggest that dietary sphingolipids can augment or prevent colon cancer, depending upon whether they are metabolized to S1P or promote S1P metabolism through the actions of SPL.
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MESH Headings
- Aldehyde-Lyases/biosynthesis
- Aldehyde-Lyases/genetics
- Animals
- Anion Transport Proteins/genetics
- Anion Transport Proteins/metabolism
- Biopsy
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/metabolism
- Colonic Neoplasms/genetics
- Colonic Neoplasms/metabolism
- Colonic Neoplasms/pathology
- Down-Regulation/genetics
- Gene Deletion
- Gene Expression Regulation, Enzymologic
- Gene Expression Regulation, Neoplastic
- Humans
- Inflammatory Bowel Diseases/genetics
- Inflammatory Bowel Diseases/metabolism
- Lysophospholipids/genetics
- Lysophospholipids/metabolism
- Mice
- Mice, Transgenic
- MicroRNAs/genetics
- MicroRNAs/metabolism
- Neoplasm Proteins/genetics
- Neoplasm Proteins/metabolism
- Neoplasms, Experimental/genetics
- Neoplasms, Experimental/metabolism
- Neoplasms, Experimental/pathology
- RNA, Neoplasm/genetics
- RNA, Neoplasm/metabolism
- STAT3 Transcription Factor/genetics
- STAT3 Transcription Factor/metabolism
- Signal Transduction/genetics
- Sphingosine/analogs & derivatives
- Sphingosine/genetics
- Sphingosine/metabolism
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Kondo S, Bottos A, Allegood JC, Masson R, Maurer FG, Genoud C, Kaeser P, Huwiler A, Murakami M, Spiegel S, Hynes NE. Memo has a novel role in S1P signaling and is [corrected] crucial for vascular development. PLoS One 2014; 9:e94114. [PMID: 24714781 PMCID: PMC3979765 DOI: 10.1371/journal.pone.0094114] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 03/13/2014] [Indexed: 11/24/2022] Open
Abstract
Memo is a conserved protein that was identified as an essential mediator of tumor cell motility induced by receptor tyrosine kinase activation. Here we show that Memo null mouse embryonic fibroblasts (MEFs) are impaired in PDGF-induced migration and this is due to a defect in sphingosine-1-phosphate (S1P) signaling. S1P is a bioactive phospholipid produced in response to multiple stimuli, which regulates many cellular processes. S1P is secreted to the extracellular milieu where it exerts its function by binding a family of G-protein coupled receptors (S1PRs), causing their activation in an autocrine or paracrine manner. The process, termed cell-autonomous S1PR signaling, plays a role in survival and migration. Indeed, PDGF uses cell-autonomous S1PR signaling to promote cell migration; we show here that this S1P pathway requires Memo. Using vascular endothelial cells (HUVECs) with Memo knock-down we show that their survival in conditions of serum-starvation is impaired. Furthermore, Memo loss in HUVECs causes a reduction of junctional VE-cadherin and an increase in sprout formation. Each of these phenotypes is rescued by S1P or S1P agonist addition, showing that Memo also plays an important role in cell-autonomous S1PR signaling in endothelial cells. We also produced conventional and endothelial cell-specific conditional Memo knock-out mouse strains and show that Memo is essential for embryonic development. Starting at E13.5 embryos of both strains display bleeding and other vascular problems, some of the phenotypes that have been described in mouse strains lacking S1PRs. The essential role of Memo in embryonic vascular development may be due in part to alterations in S1P signaling. Taken together our results show that Memo has a novel role in the S1P pathway and that Memo is needed to promote cell-autonomous S1PR activation.
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Kono M, Tucker AE, Tran J, Bergner JB, Turner EM, Proia RL. Sphingosine-1-phosphate receptor 1 reporter mice reveal receptor activation sites in vivo. J Clin Invest 2014; 124:2076-86. [PMID: 24667638 DOI: 10.1172/jci71194] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 01/23/2014] [Indexed: 12/19/2022] Open
Abstract
Activation of the GPCR sphingosine-1-phosphate receptor 1 (S1P1) by sphingosine-1-phosphate (S1P) regulates key physiological processes. S1P1 activation also has been implicated in pathologic processes, including autoimmunity and inflammation; however, the in vivo sites of S1P1 activation under normal and disease conditions are unclear. Here, we describe the development of a mouse model that allows in vivo evaluation of S1P1 activation. These mice, known as S1P1 GFP signaling mice, produce a S1P1 fusion protein containing a transcription factor linked by a protease cleavage site at the C terminus as well as a β-arrestin/protease fusion protein. Activated S1P1 recruits the β-arrestin/protease, resulting in the release of the transcription factor, which stimulates the expression of a GFP reporter gene. Under normal conditions, S1P1 was activated in endothelial cells of lymphoid tissues and in cells in the marginal zone of the spleen, while administration of an S1P1 agonist promoted S1P1 activation in endothelial cells and hepatocytes. In S1P1 GFP signaling mice, LPS-mediated systemic inflammation activated S1P1 in endothelial cells and hepatocytes via hematopoietically derived S1P. These data demonstrate that S1P1 GFP signaling mice can be used to evaluate S1P1 activation and S1P1-active compounds in vivo. Furthermore, this strategy could be potentially applied to any GPCR to identify sites of receptor activation during normal physiology and disease.
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Cenarro A, Puzo J, Ferrando J, Mateo-Gallego R, Bea AM, Calmarza P, Jarauta E, Civeira F. Effect of Nicotinic acid/Laropiprant in the lipoprotein(a) concentration with regard to baseline lipoprotein(a) concentration and LPA genotype. Metabolism 2014; 63:365-71. [PMID: 24333007 DOI: 10.1016/j.metabol.2013.10.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 10/30/2013] [Accepted: 10/30/2013] [Indexed: 11/21/2022]
Abstract
BACKGROUND Lipoprotein(a) [Lp(a)] is a lipoprotein in which apolipoproteinB-100 is linked to apolipoprotein(a) [apo(a)]. Significant variation in Lp(a) concentration is specific to LPA gene, which codes for apo(a). Nicotinic acid (NA) is used for treatment of dyslipidemias, and the lowering effect of NA on Lp(a) has been previously reported. OBJECTIVE To evaluate the Lp(a) lowering effect of 1g/20mg and 2g/40mgday of Nicotinic acid/Laropiprant in subjects with different baseline Lp(a) concentrations and depending on the LPA genotype. METHODS In an open-label, 10-week study, 1g/20mgday of NA/Laropiprant for 4weeks followed by 6weeks of 2g/40mgday conducted at 3 centers in Spain, 82 subjects were enrolled. Patients were studied at baseline and at the end of both treatment periods and were enrolled in three groups: normal Lp(a) (<50mg/dL), high Lp(a) (50-120mg/dL) and very high Lp(a) (>120mg/dL). The LPA genetic polymorphism was analyzed by a real-time PCR. RESULTS There was a significant difference in LPA genotypes among Lp(a) concentration groups and an inverse and significant correlation between baseline Lp(a) concentration and LPA genotype was found (R=-0.372, p<0.001). There were a significant decrease in total cholesterol, triglycerides, LDL cholesterol, apo B and Lp(a), and a significant increase in HDL cholesterol after NA/Laropiprant treatment, without changes in BMI. However, there were no statistical differences in percentage variation of analyzed variables depending on LPA genotype. CONCLUSION LPA genotype is a major determinant of Lp(a) baseline concentration. However, the lipid lowering effect of NA is not related to LPA genotype.
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Zhang W, Zhao J, Lee JF, Gartung A, Jawadi H, Lambiv WL, Honn KV, Lee MJ. ETS-1-mediated transcriptional up-regulation of CD44 is required for sphingosine-1-phosphate receptor subtype 3-stimulated chemotaxis. J Biol Chem 2013; 288:32126-32137. [PMID: 24064218 PMCID: PMC3820853 DOI: 10.1074/jbc.m113.495218] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 09/18/2013] [Indexed: 12/17/2022] Open
Abstract
Sphingosine-1-phosphate (S1P)-regulated chemotaxis plays critical roles in various physiological and pathophysiological conditions. S1P-regulated chemotaxis is mediated by the S1P family of G-protein-coupled receptors. However, molecular details of the S1P-regulated chemotaxis are incompletely understood. Cultured human lung adenocarcinoma cell lines abundantly express S1P receptor subtype 3 (S1P3), thus providing a tractable in vitro system to characterize molecular mechanism(s) underlying the S1P3 receptor-regulated chemotactic response. S1P treatment enhances CD44 expression and induces membrane localization of CD44 polypeptides via the S1P3/Rho kinase (ROCK) signaling pathway. Knockdown of CD44 completely diminishes the S1P-stimulated chemotaxis. Promoter analysis suggests that the CD44 promoter contains binding sites of the ETS-1 (v-ets erythroblastosis virus E26 oncogene homolog 1) transcriptional factor. ChIP assay confirms that S1P treatment stimulates the binding of ETS-1 to the CD44 promoter region. Moreover, S1P induces the expression and nuclear translocation of ETS-1. Knockdown of S1P3 or inhibition of ROCK abrogates the S1P-induced ETS-1 expression. Furthermore, knockdown of ETS-1 inhibits the S1P-induced CD44 expression and cell migration. In addition, we showed that S1P3/ROCK signaling up-regulates ETS-1 via the activity of JNK. Collectively, we characterized a novel signaling axis, i.e., ROCK-JNK-ETS-1-CD44 pathway, which plays an essential role in the S1P3-regulated chemotactic response.
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Cinq-Frais C, Coatrieux C, Grazide MH, Hannun YA, Nègre-Salvayre A, Salvayre R, Augé N. A signaling cascade mediated by ceramide, src and PDGFRβ coordinates the activation of the redox-sensitive neutral sphingomyelinase-2 and sphingosine kinase-1. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:1344-56. [PMID: 23651497 DOI: 10.1016/j.bbalip.2013.04.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 03/08/2013] [Accepted: 04/30/2013] [Indexed: 01/14/2023]
Abstract
Stress-inducing agents, including oxidative stress, generate the sphingolipid mediators ceramide (Cer) and sphingosine-1-phosphate (S1P) that are involved in stress-induced cellular responses. The two redox-sensitive neutral sphingomyelinase-2 (nSMase2) and sphingosine kinase-1 (SK1) participate in transducing stress signaling to ceramide and S1P, respectively; however, whether these key enzymes are coordinately regulated is not known. We investigated whether a signaling link coordinates nSMase2 and SK1 activation by H2O2. In mesenchymal cells, H2O2 elicits a dose-dependent biphasic effect, mitogenic at low concentration (5μM), and anti-proliferative and toxic at high concentration (100μM). Low H2O2 concentration triggered activation of nSMase2 and SK1 through a nSMase2/Cer-dependent signaling pathway that acted upstream of activation of SK1. Further results implicated src and the trans-activation of PDGFRβ, as supported by the blocking effect of specific siRNAs, pharmacological inhibitors, and genetically deficient cells for nSMase2, src and SK1. The H2O2-induced src/PDGFRβ/SK1 signaling cascade was impaired in nSMase2-deficient fro/fro cells and was rescued by exogenous C2Cer that activated src/PDGFRβ/SK1. Thus, the results define a nSMase2/SK1 signaling pathway implicated in the mitogenic response to low oxidative stress. On the other hand, high oxidative stress induced inhibition of SK1. The results also showed that the toxicity of high H2O2 concentration was comparable in control and nSMase2-deficient cells. Taken together the results identify a tightly coordinated nSMase2/SK1 pathway that mediates the mitogenic effects of H2O2 and may sense the degree of oxidative stress.
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Skill N, Wu J, Xu Y, Zhao Z, Maluccio M. Lysophosphatidic acid aberrancies and hepatocellular carcinoma: studies in the MDR2 gene knockout mouse. Cancer Invest 2013; 31:145-55. [PMID: 23362952 DOI: 10.3109/07357907.2012.762779] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Studies show that lysophosphatidic acid (LPA) reprogramming is associated with the development of hepatocellular carcinoma (HCC). This manuscript evaluates the MDR2(-/-) model of HCC as a tool to examine the role of LPA reprogramming in the initiation/progression of HCC and identify novel treatment targets. Hepatic tumors developed in MDR2(-/-) mice between 9-12 m and serum LPA levels were greater in MDR2(-/-) when compared to controls. Blocking LPA biosynthesis/signaling significantly reduced tumor burden. LPA biosynthesis/signaling plays an important role in murine MDR2(-/-) model and is potentially linked to regulation of TNFα or other cytokines that are relevant to high-risk patients.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B/deficiency
- ATP Binding Cassette Transporter, Subfamily B/genetics
- ATP Binding Cassette Transporter, Subfamily B/metabolism
- Animals
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/metabolism
- Cell Transformation, Neoplastic/pathology
- Drug Resistance, Multiple
- Liver Neoplasms/genetics
- Liver Neoplasms/pathology
- Liver Neoplasms, Experimental/blood
- Liver Neoplasms, Experimental/genetics
- Liver Neoplasms, Experimental/metabolism
- Liver Neoplasms, Experimental/pathology
- Lysophospholipids/blood
- Lysophospholipids/genetics
- Lysophospholipids/metabolism
- Mice
- Mice, Knockout
- Phosphodiesterase Inhibitors/pharmacology
- Phospholipids/metabolism
- Phosphoric Diester Hydrolases/metabolism
- Receptors, Lysosphingolipid/antagonists & inhibitors
- Receptors, Lysosphingolipid/metabolism
- Signal Transduction/drug effects
- ATP-Binding Cassette Sub-Family B Member 4
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Liang J, Nagahashi M, Kim EY, Harikumar KB, Yamada A, Huang WC, Hait NC, Allegood JC, Price MM, Avni D, Takabe K, Kordula T, Milstien S, Spiegel S. Sphingosine-1-phosphate links persistent STAT3 activation, chronic intestinal inflammation, and development of colitis-associated cancer. Cancer Cell 2013; 23:107-20. [PMID: 23273921 PMCID: PMC3578577 DOI: 10.1016/j.ccr.2012.11.013] [Citation(s) in RCA: 439] [Impact Index Per Article: 39.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 09/18/2012] [Accepted: 11/26/2012] [Indexed: 12/12/2022]
Abstract
Inflammatory bowel disease is an important risk factor for colorectal cancer. We show that sphingosine-1-phosphate (S1P) produced by upregulation of sphingosine kinase 1 (SphK1) links chronic intestinal inflammation to colitis-associated cancer (CAC) and both are exacerbated by deletion of Sphk2. S1P is essential for production of the multifunctional NF-κB-regulated cytokine IL-6, persistent activation of the transcription factor STAT3, and consequent upregulation of the S1P receptor, S1PR1. The prodrug FTY720 decreased SphK1 and S1PR1 expression and eliminated the NF-κB/IL-6/STAT3 amplification cascade and development of CAC, even in Sphk2(-/-) mice, and may be useful in treating colon cancer in individuals with ulcerative colitis. Thus, the SphK1/S1P/S1PR1 axis is at the nexus between NF-κB and STAT3 and connects chronic inflammation and CAC.
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Czimmerer Z, Varga T, Poliska S, Nemet I, Szanto A, Nagy L. Identification of novel markers of alternative activation and potential endogenous PPARγ ligand production mechanisms in human IL-4 stimulated differentiating macrophages. Immunobiology 2012; 217:1301-14. [PMID: 22954708 DOI: 10.1016/j.imbio.2012.08.270] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 07/30/2012] [Accepted: 08/02/2012] [Indexed: 01/28/2023]
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38
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Saunders LP, Cao W, Chang WC, Albright RA, Braddock DT, De La Cruz EM. Kinetic analysis of autotaxin reveals substrate-specific catalytic pathways and a mechanism for lysophosphatidic acid distribution. J Biol Chem 2011; 286:30130-41. [PMID: 21719699 PMCID: PMC3191052 DOI: 10.1074/jbc.m111.246884] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 06/23/2011] [Indexed: 01/28/2023] Open
Abstract
Autotaxin (ATX) is a secreted lysophospholipase D that hydrolyzes lysophosphatidylcholine (LPC) into lysophosphatidic acid (LPA), initiating signaling cascades leading to cancer metastasis, wound healing, and angiogenesis. Knowledge of the pathway and kinetics of LPA synthesis by ATX is critical for developing quantitative physiological models of LPA signaling. We measured the individual rate constants and pathway of the LPA synthase cycle of ATX using the fluorescent lipid substrates FS-3 and 12-(N-methyl-N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl))-LPC. FS-3 binds rapidly (k(1) ≥500 μm(-1) s(-1)) and is hydrolyzed slowly (k(2) = 0.024 s(-1)). Release of the first hydrolysis product is random and rapid (≥1 s(-1)), whereas release of the second is slow and rate-limiting (0.005-0.007 s(-1)). Substrate binding and hydrolysis are slow and rate-limiting with LPC. Product release is sequential with choline preceding LPA. The catalytic pathway and kinetics depend strongly on the substrate, suggesting that ATX kinetics could vary for the various in vivo substrates. Slow catalysis with LPC reveals the potential for LPA signaling to spread to cells distal to the site of LPC substrate binding by ATX. An ATX mutant in which catalytic threonine at position 210 is replaced with alanine binds substrate weakly, favoring a role for Thr-210 in binding as well as catalysis. FTY720P, the bioactive form of a drug currently used to treat multiple sclerosis, inhibits ATX in an uncompetitive manner and slows the hydrolysis reaction, suggesting that ATX inhibition plays a significant role in lymphocyte immobilization in FTY720P-based therapeutics.
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Kim EK, Park JM, Lim S, Choi JW, Kim HS, Seok H, Seo JK, Oh K, Lee DS, Kim KT, Ryu SH, Suh PG. Activation of AMP-activated protein kinase is essential for lysophosphatidic acid-induced cell migration in ovarian cancer cells. J Biol Chem 2011; 286:24036-45. [PMID: 21602274 PMCID: PMC3129185 DOI: 10.1074/jbc.m110.209908] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 05/05/2011] [Indexed: 01/30/2023] Open
Abstract
Lysophosphatidic acid (LPA) is a bioactive phospholipid that affects various biological functions, such as cell proliferation, migration, and survival, through LPA receptors. Among them, the motility of cancer cells is an especially important activity for invasion and metastasis. Recently, AMP-activated protein kinase (AMPK), an energy-sensing kinase, was shown to regulate cell migration. However, the specific role of AMPK in cancer cell migration is unknown. The present study investigated whether LPA could induce AMPK activation and whether this process was associated with cell migration in ovarian cancer cells. We found that LPA led to a striking increase in AMPK phosphorylation in pathways involving the phospholipase C-β3 (PLC-β3) and calcium/calmodulin-dependent protein kinase kinase β (CaMKKβ) in SKOV3 ovarian cancer cells. siRNA-mediated knockdown of AMPKα1, PLC-β3, or (CaMKKβ) impaired the stimulatory effects of LPA on cell migration. Furthermore, we found that knockdown of AMPKα1 abrogated LPA-induced activation of the small GTPase RhoA and ezrin/radixin/moesin proteins regulating membrane dynamics as membrane-cytoskeleton linkers. In ovarian cancer xenograft models, knockdown of AMPK significantly decreased peritoneal dissemination and lung metastasis. Taken together, our results suggest that activation of AMPK by LPA induces cell migration through the signaling pathway to cytoskeletal dynamics and increases tumor metastasis in ovarian cancer.
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Shimizu Y, Tokumura A. [Physiological role of lysophosphatidic acid and its relevancephysiological role of lysophosphatidic acid and its relevance to diseases]. SEIKAGAKU. THE JOURNAL OF JAPANESE BIOCHEMICAL SOCIETY 2011; 83:506-517. [PMID: 21800681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
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41
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Kanno T, Nishizaki T, Proia RL, Kajimoto T, Jahangeer S, Okada T, Nakamura S. Regulation of synaptic strength by sphingosine 1-phosphate in the hippocampus. Neuroscience 2010; 171:973-80. [PMID: 20950672 DOI: 10.1016/j.neuroscience.2010.10.021] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2010] [Revised: 10/05/2010] [Accepted: 10/07/2010] [Indexed: 11/19/2022]
Abstract
Although the hippocampus is a brain region involved in short-term memory, the molecular mechanisms underlying memory formation are not completely understood. Here we show that sphingosine 1-phosphate (S1P) plays a pivotal role in the formation of memory. Addition of S1P to rat hippocampal slices increased the rate of AMPA receptor-mediated miniature excitatory postsynaptic currents (mEPSCs) recorded from the CA3 region of the hippocampus. In addition long-term potentiation (LTP) observed in the CA3 region was potently inhibited by a sphingosine kinase (SphK) inhibitor and this inhibition was fully reversed by S1P. LTP was impaired in hippocampal slices specifically in the CA3 region obtained from SphK1-knockout mice, which correlates well with the poor performance of these animals in the Morris water maze test. These results strongly suggest that SphK/S1P receptor signaling plays an important role in excitatory synaptic transmission in the CA3 region of hippocampus and has profound effects on hippocampal function such as spatial learning.
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Hagen N, Van Veldhoven PP, Proia RL, Park H, Merrill AH, van Echten-Deckert G. Subcellular origin of sphingosine 1-phosphate is essential for its toxic effect in lyase-deficient neurons. J Biol Chem 2009; 284:11346-53. [PMID: 19251691 PMCID: PMC2670140 DOI: 10.1074/jbc.m807336200] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2008] [Revised: 02/25/2009] [Indexed: 11/06/2022] Open
Abstract
Cerebellar granule cells from sphingosine 1-phosphate (S1P) lyase-deficient mice were used to study the toxicity of this potent sphingolipid metabolite in terminally differentiated postmitotic neurons. Based on earlier findings with the lyase-stable, semi-synthetic, cis-4-methylsphingosine phosphate, we hypothesized that accumulation of S1P above a certain threshold induces neuronal apoptosis. The present studies confirmed this conclusion and further revealed that for S1P to induce apoptosis in lyase-deficient neurons it must also be produced by sphingosine-kinase2 (SK2). These conclusions are based on the finding that incubation of lyase-deficient neurons with either sphingosine or S1P results in a similar elevation in cellular S1P; however, only S1P addition to the culture medium induces apoptosis. This was not due to S1P acting on the S1P receptor but to hydrolysis of S1P to sphingosine that was phosphorylated by the cells, as described before for cis-4-methylsphingosine. Although the cells produced S1P from both exogenously added sphingosine as well as sphingosine derived from exogenous S1P, the S1P from these two sources were not equivalent, because the former was primarily produced by SK1, whereas the latter was mainly formed by SK2 (as also was cis-4-methylsphingosine phosphate), based on studies in neurons lacking SK1 or SK2 activity. Thus, these investigations show that, due to the existence of at least two functionally distinct intracellular origins for S1P, exogenous S1P can be neurotoxic. In this model, S1P accumulated due to a defective lyase, however, this cause of toxicity might also be important in other cases, as illustrated by the neurotoxicity of cis-4-methylsphingosine phosphate.
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Huang WR, Wang LS, Wang H, Duan HF, Li QF, Gao CJ, DA WM. [SphK-1/S1P signal pathway in CML cells]. ZHONGGUO SHI YAN XUE YE XUE ZA ZHI 2008; 16:730-733. [PMID: 18718048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Chronic myelogenous leukemia (CML) is a clonal myeloproliferative disease of transformed hematopoietic progenitor cells. In order to investigate the role of sphingosine kinase-1 (SphK-1)/sphingosine 1-phosphate (S1P) signal pathway in the expression of CML cells, and to explore whether P210(bcr/abl) involved is activating SphK-1/S1P signal pathwey, the expressions of SphK-1 and S1P receptor mRNA in bcr/abl positive K562 cells and bcr/abl positive primary CML cells were detected by RT-PCR, the imatinib mesylate, the specific inhibitor of P210(bcr/abl) was employed to inhibit the P210(bcr/abl) tyrosine kinases of K562 cells and CML primary cells, and then the intracellular SphK-1 activity was assayed. The results indicated that after being cultured with 2.5 micromol/L imatinib mesylate for 0.5, 2, 6, 24 and 48 hours, the intensions of inhibiting SphK-1 activity were 0.007%, 38.9%, 34.6%, 28.1% and 76.1% resepectively. SphK-1 activity in CML cells also was reduced by 2.5 micromol/L imatinib mesylate (16.8% - 41.9% decrease). It is concluded that the CML cells express SphK-1 and different S1P receptor, and P210(bcr/abl) fusion protein in CML cells can activate SphK-1.
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MESH Headings
- Benzamides
- Fusion Proteins, bcr-abl/genetics
- Fusion Proteins, bcr-abl/metabolism
- Humans
- Imatinib Mesylate
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism
- Lysophospholipids/genetics
- Lysophospholipids/metabolism
- Phosphotransferases (Alcohol Group Acceptor)/genetics
- Phosphotransferases (Alcohol Group Acceptor)/metabolism
- Piperazines/pharmacology
- Pyrimidines/pharmacology
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Signal Transduction/genetics
- Sphingosine/analogs & derivatives
- Sphingosine/genetics
- Sphingosine/metabolism
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Leclercq TM, Moretti PAB, Vadas MA, Pitson SM. Eukaryotic elongation factor 1A interacts with sphingosine kinase and directly enhances its catalytic activity. J Biol Chem 2008; 283:9606-14. [PMID: 18263879 PMCID: PMC2442288 DOI: 10.1074/jbc.m708782200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Revised: 01/23/2008] [Indexed: 01/07/2023] Open
Abstract
Sphingosine 1-phosphate (S1P) has many important roles in mammalian cells, including contributing to the control of cell survival and proliferation. S1P is generated by sphingosine kinases (SKs), of which two mammalian isoforms have been identified (SK1 and SK2). To gain a better understanding of SK regulation, we have used a yeast two-hybrid screen to identify SK1-interacting proteins and established elongation factor 1A (eEF1A) as one such protein that associates with both SK1 and SK2. We show the direct interaction of eEF1A with the SKs in vitro, whereas the physiological relevance of this association was demonstrated by co-immunoprecipitation of the endogenous proteins from cell lysates. Although the canonical role of eEF1A resides in protein synthesis, it has also been implicated in other roles, including regulating the activity of some signaling enzymes. Thus, we examined the potential role of eEF1A in regulation of the SKs and show that eEF1A is able to directly increase the activity of SK1 and SK2 approximately 3-fold in vitro. Substrate kinetics demonstrated that eEF1A increased the catalytic rate of both SKs, while having no observable effect on substrate affinities of these enzymes for either ATP or sphingosine. Overexpression of eEF1A in quiescent Chinese hamster ovary cells increased cellular SK activity, whereas a small interfering RNA-mediated decrease in eEF1A levels in MCF7 cells substantially reduced cellular SK activity and S1P levels, supporting the in vivo physiological relevance of this interaction. Thus, this study has established a novel mechanism of regulation of both SK1 and SK2 that is mediated by their interaction with eEF1A.
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Tamaki H, Shimada A, Ito Y, Ohya M, Takase J, Miyashita M, Miyagawa H, Nozaki H, Nakayama R, Kumagai H. LPT1 encodes a membrane-bound O-acyltransferase involved in the acylation of lysophospholipids in the yeast Saccharomyces cerevisiae. J Biol Chem 2007; 282:34288-98. [PMID: 17890783 DOI: 10.1074/jbc.m704509200] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phospholipids are major components of cellular membranes that participate in a range of cellular processes. Phosphatidic acid (PA) is a key molecule in the phospholipid biosynthetic pathway. In Saccharomyces cerevisiae, SLC1 has been identified as the gene encoding lysophosphatidic acid acyltransferase, which catalyzes PA synthesis. However, despite the importance of PA, disruption of SLC1 does not affect cell viability (Nagiec, M. M., Wells, G. B., Lester, R. L., and Dickson, R. C. (1993) J. Biol. Chem. 268, 22156-22163). We originally aimed to identify the acetyl-CoA:lyso platelet-activating factor acetyltransferase (lysoPAF AT) gene in yeast. Screening of a complete set of yeast deletion clones (4741 homozygous diploid clones) revealed a single mutant strain, YOR175c, with a defect in lysoPAF AT activity. YOR175c has been predicted to be a member of the membrane-bound O-acyltransferase superfamily, and we designated the gene LPT1. An Lpt1-green fluorescent protein fusion protein localized at the endoplasmic reticulum. Other than lysoPAF AT activity, Lpt1 catalyzed acyltransferase activity with a wide variety of lysophospholipids as acceptors, including lysophosphatidic acid, lysophosphatidylcholine, lysophosphatidylethanolamine, lysophosphatidylglycerol, lysophosphatidylinositol, and lysophosphatidylserine. A liquid chromatography-mass spectrometry analysis indicated that lysophosphatidylcholine and lysophosphatidylethanolamine accumulated in the Deltalpt1 mutant strain. Although the Deltalpt1 mutant strain did not show other detectable defects, the Deltalpt1 Deltaslc1 double mutant strain had a synthetic lethal phenotype. These results indicate that, in concert with Slc1, Lpt1 plays a central role in PA biosynthesis, which is essential for cell viability.
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Riekhof WR, Wu J, Jones JL, Voelker DR. Identification and characterization of the major lysophosphatidylethanolamine acyltransferase in Saccharomyces cerevisiae. J Biol Chem 2007; 282:28344-28352. [PMID: 17652094 DOI: 10.1074/jbc.m705256200] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We recently demonstrated that yeast actively import lysophosphatidylethanolamine (lyso-PtdEtn) through the action of plasma membrane P-type ATPases and rapidly acylate it to form PtdEtn. The predominant lyso-PtdEtn acyltransferase (LPEAT) activity present in cellular extracts is acyl-CoA dependent, but the identity of the gene encoding this activity was unknown. We now demonstrate that a previously uncharacterized open reading frame, YOR175C, encodes the major acyl-CoA-dependent LPEAT activity in yeast and henceforth refer to it as ALE1 (acyltransferase for lyso-PtdEtn). Ale1p is an integral membrane protein and is highly enriched in the mitochondria-associated endoplasmic reticulum membrane. It is a member of the membrane-bound O-acyltransferase family and possesses a dibasic motif at its C terminus that is likely responsible for Golgi retrieval and retention in the endoplasmic reticulum. An ale1Delta strain retains only trace amounts of acyl-CoA-dependent LPEAT activity, and strains lacking the capacity for PtdEtn synthesis via the phosphatidylserine decarboxylase and Kennedy pathways show a stringent requirement for both exogenous lyso-PtdEtn and a functional ALE1 gene for viability. Ale1p catalytic activity has a pH optimum between pH 7 and 7.5 and a strong preference for unsaturated acyl-CoA substrates.
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Huang MC, Watson SR, Liao JJ, Goetzl EJ. Th17 augmentation in OTII TCR plus T cell-selective type 1 sphingosine 1-phosphate receptor double transgenic mice. THE JOURNAL OF IMMUNOLOGY 2007; 178:6806-13. [PMID: 17513728 DOI: 10.4049/jimmunol.178.11.6806] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Sphingosine 1-phosphate (S1P) in blood and lymph controls lymphoid traffic and tissue migration of T cells through signals from the type 1 S1PR (S1P(1)), but less is known of effects of the S1P-S1P(1) axis on nonmigration functions of T cells. CD4 T cells from a double transgenic (DTG) mouse express OTII TCRs specific for OVA peptide 323-339 (OVA) and a high level of transgenic S1P(1), resistant to suppression by T cell activation. OVA-activated DTG CD4 T cells respond as expected to S1P by chemotactic migration and reduction in secretion of IFN-gamma. In addition, DTG CD4 T cells stimulated by OVA secrete a mean of 2.5-fold more IL-17 than those from OTII single transgenic mice with concomitantly higher levels of mRNA encoding IL-17 by real-time PCR and of CD4 T cells with intracellular IL-17 detected by ELISPOT assays. OVA challenge of s.c. air pockets elicited influx of more OTII TCR-positive T cells producing a higher level of IL-17 in DTG mice than OTII control mice. Augmentation of the number and activity of Th17 cells by the S1P-S1P(1) axis may thus enhance host defense against microbes and in other settings increase host susceptibility to autoimmune diseases.
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Walter DH, Rochwalsky U, Reinhold J, Seeger F, Aicher A, Urbich C, Spyridopoulos I, Chun J, Brinkmann V, Keul P, Levkau B, Zeiher AM, Dimmeler S, Haendeler J. Sphingosine-1-Phosphate Stimulates the Functional Capacity of Progenitor Cells by Activation of the CXCR
4
-Dependent Signaling Pathway via the S1P
3
Receptor. Arterioscler Thromb Vasc Biol 2007; 27:275-82. [PMID: 17158356 DOI: 10.1161/01.atv.0000254669.12675.70] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Objective—
Sphingosine-1-phosphate (S1P) is a bioactive lipid, which influences migration and proliferation of endothelial cells through activation of S1P receptors and has been shown to support SDF-1 induced migration and bone marrow homing of CD34
+
progenitors.
Methods and Results—
Here, we show that incubation of patient-derived endothelial progenitor cells (EPCs) with S1P or its synthetic analog FTY720 improved blood flow recovery in ischemic hind limbs. Likewise, recovery of blood flow was dramatically reduced after induction of hindlimb ischemia in mice deficient for the S1P receptor 3 (S1P
3
). S1P
3
−/−
bone marrow–derived mononuclear cells (BMCs) failed to augment neovascularization after hind limb ischemia. Of note, treatment of BMCs derived from S1P
3
−/−
mice with S1P did not rescue blood flow recovery. Mechanistically, S1P and FTY720 induced phosphorylation of CXCR
4
, activated the Src kinase, and stimulated phosphorylation of JAK2. The contribution of CXCR
4
for S1P-mediated effects was further supported by the findings that S1P preincubation failed to stimulate invasion capacity and in vivo blood flow recovery of BMCs from CXCR
4
+/−
mice. The activation of CXCR
4
was dependent on the Src kinase family as demonstrated by preincubation with the Src inhibitor PP2. The activation of the CXCR
4
signaling by S1P is mediated via the S1P
3
receptor, since S1P-induced Src phosphorylation was abrogated in EPC from S1P
3
−/−
mice.
Conclusions—
S1P agonists might serve as sensitizers of CXCR
4
-mediated signaling and may be applied in clinical progenitor cell therapy to improve EPC or BMC function in patients with coronary artery disease.
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Suzuki H, Riley RT, Sharma RP. Inducible nitric oxide has protective effect on fumonisin B1 hepatotoxicity in mice via modulation of sphingosine kinase. Toxicology 2007; 229:42-53. [PMID: 17095132 PMCID: PMC1850950 DOI: 10.1016/j.tox.2006.09.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2006] [Revised: 09/14/2006] [Accepted: 09/25/2006] [Indexed: 10/24/2022]
Abstract
Fumonisin B(1), a mycotoxin, is an inhibitor of ceramide synthase causing marked dysregulation of sphingolipid metabolism in cells. This mycotoxin causes accumulation of free sphingoid bases (sphingosine and dihydrosphingosine or sphinganine) and their metabolites, important messengers involved in signal transduction leading to either cell survival or death. Free sphingoid bases are known apoptotic molecules whereas sphingosine 1-phosphate is protective. We previously reported that fumonisin B(1) caused sphingosine kinase (SPHK) induction along with the increase of serine palmitoyltransferase (SPT). Fumonisin B(1) also increased inducible nitric oxide synthase (iNOS) expression. In the current study we employed a mouse strain with the targeted deletion of iNOS gene (Nos-KO) to evaluate the role of nitric oxide (NO) on fumonisin B(1)-induced hepatotoxicity. The Nos-KO mice exhibited increased hepatotoxicity after subacute fumonisin B(1) exposure compared to their wild type counterparts, the liver regeneration was lower in Nos-KO compared to that in the WT mice. Increased hepatotoxicity in Nos-KO was not related to the extent of free sphingoid base accumulation after fumonisin B(1) treatment; however, it was accompanied by a lack of fumonisin B(1)-induced SPHK induction. The fumonisin B(1)-induced SPT was unaffected by lack of iNOS gene. Deletion of iNOS gene did not prevent fumonisin B(1)-dependent induction of inflammatory cytokines, namely tumor necrosis factor alpha, interferon gamma and interleukin-12. The lack of fumonisin B(1)-induced SPHK induction in Nos-KO was supported by a similar effect on phosphorylated metabolites of sphingoid bases; the equilibrium between sphingoid bases and their phosphates is maintained by SPHK. We therefore conclude that iNOS induction produced by fumonisin B(1) modulates SPHK activity; the lack of iNOS prevents generation of sphingosine 1-phosphate and deprives cells from its protective effects.
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Natarajan J, Berrar D, Dubitzky W, Hack C, Zhang Y, DeSesa C, Van Brocklyn JR, Bremer EG. Text mining of full-text journal articles combined with gene expression analysis reveals a relationship between sphingosine-1-phosphate and invasiveness of a glioblastoma cell line. BMC Bioinformatics 2006; 7:373. [PMID: 16901352 PMCID: PMC1557675 DOI: 10.1186/1471-2105-7-373] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2006] [Accepted: 08/10/2006] [Indexed: 11/29/2022] Open
Abstract
Background Sphingosine 1-phosphate (S1P), a lysophospholipid, is involved in various cellular processes such as migration, proliferation, and survival. To date, the impact of S1P on human glioblastoma is not fully understood. Particularly, the concerted role played by matrix metalloproteinases (MMP) and S1P in aggressive tumor behavior and angiogenesis remains to be elucidated. Results To gain new insights in the effect of S1P on angiogenesis and invasion of this type of malignant tumor, we used microarrays to investigate the gene expression in glioblastoma as a response to S1P administration in vitro. We compared the expression profiles for the same cell lines under the influence of epidermal growth factor (EGF), an important growth factor. We found a set of 72 genes that are significantly differentially expressed as a unique response to S1P. Based on the result of mining full-text articles from 20 scientific journals in the field of cancer research published over a period of five years, we inferred gene-gene interaction networks for these 72 differentially expressed genes. Among the generated networks, we identified a particularly interesting one. It describes a cascading event, triggered by S1P, leading to the transactivation of MMP-9 via neuregulin-1 (NRG-1), vascular endothelial growth factor (VEGF), and the urokinase-type plasminogen activator (uPA). This interaction network has the potential to shed new light on our understanding of the role played by MMP-9 in invasive glioblastomas. Conclusion Automated extraction of information from biological literature promises to play an increasingly important role in biological knowledge discovery. This is particularly true for high-throughput approaches, such as microarrays, and for combining and integrating data from different sources. Text mining may hold the key to unraveling previously unknown relationships between biological entities and could develop into an indispensable instrument in the process of formulating novel and potentially promising hypotheses.
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