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Sample records for 1-phosphate s1p receptors

  1. Highly selective and potent agonists of sphingosine-1-phosphate 1 (S1P1) receptor.

    PubMed

    Vachal, Petr; Toth, Leslie M; Hale, Jeffrey J; Yan, Lin; Mills, Sander G; Chrebet, Gary L; Koehane, Carol A; Hajdu, Richard; Milligan, James A; Rosenbach, Mark J; Mandala, Suzanne

    2006-07-15

    Novel series of sphingosine-1-phosphate (S1P) receptor agonists were developed through a systematic SAR aimed to achieve high selectivity for a single member of the S1P family of receptors, S1P1. The optimized structure represents a highly S1P1-selective and efficacious agonist: S1P1/S1P2, S1P1/S1P3, S1P1/S1P4>10,000-fold, S1P1/S1P5>600-fold, while EC50 (S1P1) <0.2 nM. In vivo experiments are consistent with S1P1 receptor agonism alone being sufficient for achieving desired lymphocyte-lowering effect.

  2. New fluorinated agonists for targeting the sphingosin-1-phosphate receptor 1 (S1P(1)).

    PubMed

    Shaikh, Rizwan S; Keul, Petra; Schäfers, Michael; Levkau, Bodo; Haufe, Günter

    2015-11-15

    The sphingosine-1-phosphate receptor type 1 (S1P1) is involved in fundamental biological processes such as regulation of immune cell trafficking, vascular barrier function and angiogenesis. This Letter presents multistep syntheses of various fluorine substituted 12-aryl analogues of the drug fingolimod (FTY720) and a seven-steps route to 2-amino-17,17-difluoro-2-(hydroxymethyl)heptadecan-1-ol. In vitro and in vivo tests proved all these compounds as potent S1P1 receptor agonists.

  3. Sphingosine 1-phosphate (S1P)/S1P receptor 1 signaling regulates receptor activator of NF-{kappa}B ligand (RANKL) expression in rheumatoid arthritis

    SciTech Connect

    Takeshita, Harunori; Kitano, Masayasu; Iwasaki, Tsuyoshi; Kitano, Sachie; Tsunemi, Sachi; Sato, Chieri; Sekiguchi, Masahiro; Azuma, Naoto; Miyazawa, Keiji; Hla, Timothy; Sano, Hajime

    2012-03-09

    Highlights: Black-Right-Pointing-Pointer MH7A cells and CD4{sup +} T cells expressed S1P1 and RANKL. Black-Right-Pointing-Pointer S1P increased RANKL expression in MH7A cells and CD4{sup +} T cells. Black-Right-Pointing-Pointer The effect of S1P in MH7A cells was inhibited by specific Gi/Go inhibitors. -- Abstract: Sphingosine 1-phosphate (S1P)/S1P receptor 1 (S1P1) signaling plays an important role in synovial cell proliferation and inflammatory gene expression by rheumatoid arthritis (RA) synoviocytes. The purpose of this study is to clarify the role of S1P/S1P1 signaling in the expression of receptor activator of NF-{kappa}B ligand (RANKL) in RA synoviocytes and CD4{sup +} T cells. We demonstrated MH7A cells, a human RA synovial cell line, and CD4{sup +} T cells expressed S1P1 and RANKL. Surprisingly, S1P increased RANKL expression in MH7A cells and CD4{sup +} T cells in a dose-dependent manner. Moreover, S1P enhanced RANKL expression induced by stimulation with TNF-{alpha} in MH7A cells and CD4{sup +} T cells. These effects of S1P in MH7A cells were inhibited by pretreatment with PTX, a specific Gi/Go inhibitor. These findings suggest that S1P/S1P1 signaling may play an important role in RANKL expression by MH7A cells and CD4{sup +} T cells. S1P/S1P1 signaling of RA synoviocytes is closely connected with synovial hyperplasia, inflammation, and RANKL-induced osteoclastogenesis in RA. Thus, regulation of S1P/S1P1 signaling may become a novel therapeutic target for RA.

  4. Discovery of potent 3,5-diphenyl-1,2,4-oxadiazole sphingosine-1-phosphate-1 (S1P1) receptor agonists with exceptional selectivity against S1P2 and S1P3.

    PubMed

    Li, Zhen; Chen, Weirong; Hale, Jeffrey J; Lynch, Christopher L; Mills, Sander G; Hajdu, Richard; Keohane, Carol Ann; Rosenbach, Mark J; Milligan, James A; Shei, Gan-Ju; Chrebet, Gary; Parent, Stephen A; Bergstrom, James; Card, Deborah; Forrest, Michael; Quackenbush, Elizabeth J; Wickham, L Alexandra; Vargas, Hugo; Evans, Rose M; Rosen, Hugh; Mandala, Suzanne

    2005-10-01

    A class of 3,5-diphenyl-1,2,4-oxadiazole based compounds have been identified as potent sphingosine-1-phosphate-1 (S1P1) receptor agonists with minimal affinity for the S1P2 and S1P3 receptor subtypes. Analogue 26 (S1P1 IC50 = 0.6 nM) has an excellent pharmacokinetics profile in the rat and dog and is efficacious in a rat skin transplant model, indicating that S1P3 receptor agonism is not a component of immunosuppressive efficacy.

  5. Sphingosine 1-Phosphate (S1P) Receptor Agonists Mediate Pro-fibrotic Responses in Normal Human Lung Fibroblasts via S1P2 and S1P3 Receptors and Smad-independent Signaling

    PubMed Central

    Sobel, Katrin; Menyhart, Katalin; Killer, Nina; Renault, Bérengère; Bauer, Yasmina; Studer, Rolf; Steiner, Beat; Bolli, Martin H.; Nayler, Oliver; Gatfield, John

    2013-01-01

    Synthetic sphingosine 1-phosphate receptor 1 modulators constitute a new class of drugs for the treatment of autoimmune diseases. Sphingosine 1-phosphate (S1P) signaling, however, is also involved in the development of fibrosis. Using normal human lung fibroblasts, we investigated the induction of fibrotic responses by the S1P receptor (S1PR) agonists S1P, FTY720-P, ponesimod, and SEW2871 and compared them with the responses induced by the known fibrotic mediator TGF-β1. In contrast to TGF-β1, S1PR agonists did not induce expression of the myofibroblast marker α-smooth muscle actin. However, TGF-β1, S1P, and FTY720-P caused robust stimulation of extracellular matrix (ECM) synthesis and increased pro-fibrotic marker gene expression including connective tissue growth factor. Ponesimod showed limited and SEW2871 showed no pro-fibrotic potential in these readouts. Analysis of pro-fibrotic signaling pathways showed that in contrast to TGF-β1, S1PR agonists did not activate Smad2/3 signaling but rather activated PI3K/Akt and ERK1/2 signaling to induce ECM synthesis. The strong induction of ECM synthesis by the nonselective agonists S1P and FTY720-P was due to the stimulation of S1P2 and S1P3 receptors, whereas the weaker induction of ECM synthesis at high concentrations of ponesimod was due to a low potency activation of S1P3 receptors. Finally, in normal human lung fibroblast-derived myofibroblasts that were generated by TGF-β1 pretreatment, S1P and FTY720-P were effective stimulators of ECM synthesis, whereas ponesimod was inactive, because of the down-regulation of S1P3R expression in myofibroblasts. These data demonstrate that S1PR agonists are pro-fibrotic via S1P2R and S1P3R stimulation using Smad-independent pathways. PMID:23589284

  6. Discovery of Tetrahydropyrazolopyridine as Sphingosine 1-Phosphate Receptor 3 (S1P3)-Sparing S1P1 Agonists Active at Low Oral Doses.

    PubMed

    Demont, Emmanuel H; Bailey, James M; Bit, Rino A; Brown, Jack A; Campbell, Colin A; Deeks, Nigel; Dowell, Simon J; Eldred, Colin; Gaskin, Pam; Gray, James R J; Haynes, Andrea; Hirst, David J; Holmes, Duncan S; Kumar, Umesh; Morse, Mary A; Osborne, Greg J; Renaux, Jessica F; Seal, Gail A L; Smethurst, Chris A; Taylor, Simon; Watson, Robert; Willis, Robert; Witherington, Jason

    2016-02-11

    FTY720 is the first oral small molecule approved for the treatment of people suffering from relapsing-remitting multiple sclerosis. It is a potent agonist of the S1P1 receptor, but its lack of selectivity against the S1P3 receptor has been linked to most of the cardiovascular side effects observed in the clinic. These findings have triggered intensive efforts toward the identification of a second generation of S1P3-sparing S1P1 agonists. We have recently disclosed a series of orally active tetrahydroisoquinoline (THIQ) compounds matching these criteria. In this paper we describe how we defined and implemented a strategy aiming at the discovery of selective structurally distinct follow-up agonists. This effort culminated with the identification of a series of orally active tetrahydropyrazolopyridines. PMID:26751273

  7. Roles of sphingosine-1-phosphate (S1P) receptors in malignant behavior of glioma cells. Differential effects of S1P{sub 2} on cell migration and invasiveness

    SciTech Connect

    Young, Nicholas; Van Brocklyn, James R. . E-mail: james.vanbrocklyn@osumc.edu

    2007-05-01

    Sphingosine-1-phosphate (S1P) is a bioactive lipid that signals through a family of five G-protein-coupled receptors, termed S1P{sub 1-5}. S1P stimulates growth and invasiveness of glioma cells, and high expression levels of the enzyme that forms S1P, sphingosine kinase-1, correlate with short survival of glioma patients. In this study we examined the mechanism of S1P stimulation of glioma cell proliferation and invasion by either overexpressing or knocking down, by RNA interference, S1P receptor expression in glioma cell lines. S1P{sub 1}, S1P{sub 2} and S1P{sub 3} all contribute positively to S1P-stimulated glioma cell proliferation, with S1P{sub 1} being the major contributor. Stimulation of glioma cell proliferation by these receptors correlated with activation of ERK MAP kinase. S1P{sub 5} blocks glioma cell proliferation, and inhibits ERK activation. S1P{sub 1} and S1P{sub 3} enhance glioma cell migration and invasion. S1P{sub 2} inhibits migration through Rho activation, Rho kinase signaling and stress fiber formation, but unexpectedly, enhances glioma cell invasiveness by stimulating cell adhesion. S1P{sub 2} also potently enhances expression of the matricellular protein CCN1/Cyr61, which has been implicated in tumor cell adhesion, and invasion as well as tumor angiogenesis. A neutralizing antibody to CCN1 blocked S1P{sub 2}-stimulated glioma invasion. Thus, while S1P{sub 2} decreases glioma cell motility, it may enhance invasion through induction of proteins that modulate glioma cell interaction with the extracellular matrix.

  8. 2,5-Disubstituted pyrrolidine carboxylates as potent, orally active sphingosine-1-phosphate (S1P) receptor agonists.

    PubMed

    Colandrea, Vincent J; Legiec, Irene E; Huo, Pei; Yan, Lin; Hale, Jeffrey J; Mills, Sander G; Bergstrom, James; Card, Deborah; Chebret, Gary; Hajdu, Richard; Keohane, Carol Ann; Milligan, James A; Rosenbach, Mark J; Shei, Gan-Ju; Mandala, Suzanne M

    2006-06-01

    A series of 2,5-cis-disubstituted pyrrolidines were synthesized and evaluated as S1P receptor agonists. Compounds 15-21 were identified with good selectivity over S1P3 which lowered circulating lymphocytes after oral administration in mice.

  9. HDL-bound sphingosine 1-phosphate acts as a biased agonist for the endothelial cell receptor S1P1 to limit vascular inflammation

    PubMed Central

    Galvani, Sylvain; Sanson, Marie; Blaho, Victoria A.; Swendeman, Steven L.; Obinata, Hideru; Conger, Heather; Dahlbäck, Björn; Kono, Mari; Proia, Richard L.; Smith, Jonathan D.; Hla, Timothy

    2016-01-01

    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. PMID:26268607

  10. 2-Aryl(pyrrolidin-4-yl)acetic acids are potent agonists of sphingosine-1-phosphate (S1P) receptors.

    PubMed

    Yan, Lin; Budhu, Richard; Huo, Pei; Lynch, Christopher L; Hale, Jeffrey J; Mills, Sander G; Hajdu, Richard; Keohane, Carol A; Rosenbach, Mark J; Milligan, James A; Shei, Gan-Ju; Chrebet, Gary; Bergstrom, James; Card, Deborah; Mandala, Suzanne M

    2006-07-01

    A series of 2-aryl(pyrrolidin-4-yl)acetic acids were synthesized and their biological activities were evaluated as agonists of S1P receptors. These analogs were able to induce lowering of lymphocyte counts in the peripheral blood of mice and were found to have good overall pharmacokinetic properties in rat.

  11. Sphingosine-1-phosphate receptor-1 (S1P1) is expressed by lymphocytes, dendritic cells, and endothelium and modulated during inflammatory bowel disease

    PubMed Central

    Karuppuchamy, Thangaraj; Behrens, En-hui; González-Cabrera, Pedro; Sarkisyan, Gor; Gima, Lauren; Boyer, Joshua D.; Bamias, Giorgos; Jedlicka, Paul; Veny, Marisol; Clark, David; Peach, Robert; Scott, Fiona; Rosen, Hugh; Rivera-Nieves, Jesús

    2016-01-01

    The sphingosine-1-phosphate receptor-1 (S1P1) agonist ozanimod ameliorates ulcerative colitis, yet its mechanism of action is unknown. Here we examine the cell subsets that express S1P1 in intestine using S1P1-eGFP mice, the regulation of S1P1 expression in lymphocytes after administration of DSS, after colitis induced by transfer of CD4+CD45RBhi cells and by crossing a mouse with TNF-driven ileitis with S1P1-eGFP mice. We then assayed the expression of enzymes that regulate intestinal S1P levels, and the effect of FTY720 on lymphocyte behavior and S1P1 expression. We found that not only T and B cells express S1P1, but also dendritic (DC) and endothelial cells. Furthermore, chronic but not acute inflammatory signals increased S1P1 expression, while the enzymes that control tissue S1P levels in mice and humans with IBD were uniformly dysregulated, favoring synthesis over degradation. Finally, we observed that FTY720 reduced T cell velocity and induced S1P1 degradation and retention of naïve but not effector T cells. Our data demonstrate that chronic inflammation modulates S1P1 expression and tissue S1P levels and suggests that the anti-inflammatory properties of S1PR agonists might not be solely due to their lymphopenic effects, but also due to potential effects on DC migration and vascular barrier function. PMID:27049060

  12. Discovery of A-971432, An Orally Bioavailable Selective Sphingosine-1-Phosphate Receptor 5 (S1P5) Agonist for the Potential Treatment of Neurodegenerative Disorders.

    PubMed

    Hobson, Adrian D; Harris, Christopher M; van der Kam, Elizabeth L; Turner, Sean C; Abibi, Ayome; Aguirre, Ana L; Bousquet, Peter; Kebede, Tegest; Konopacki, Donald B; Gintant, Gary; Kim, Youngjae; Larson, Kelly; Maull, John W; Moore, Nigel S; Shi, Dan; Shrestha, Anurupa; Tang, Xiubo; Zhang, Peng; Sarris, Kathy K

    2015-12-10

    S1P5 is one of 5 receptors for sphingosine-1-phosphate and is highly expressed on endothelial cells within the blood-brain barrier, where it maintains barrier integrity in in vitro models (J. Neuroinflamm. 2012, 9, 133). Little more is known about the effects of S1P5 modulation due to the absence of tool molecules with suitable selectivity and drug-like properties. We recently reported that molecule A-971432 (Harris, 2010) (29 in this paper) is highly efficacious in reversing lipid accumulation and age-related cognitive decline in rats (Van der Kam , , AAIC 2014). Herein we describe the development of a series of selective S1P5 agonists that led to the identification of compound 29, which is highly selective for S1P5 and has excellent plasma and CNS exposure after oral dosing in preclinical species. To further support its suitability for in vivo studies of S1P5 biology, we extensively characterized 29, including confirmation of its selectivity in pharmacodynamic assays of S1P1 and S1P3 function in rats. In addition, we found that 29 improves blood-brain barrier integrity in an in vitro model and reverses age-related cognitive decline in mice. These results suggest that S1P5 agonism is an innovative approach with potential benefit in neurodegenerative disorders involving lipid imbalance and/or compromised blood-brain barrier such as Alzheimer's disease or multiple sclerosis. PMID:26509640

  13. Discovery of 3-arylpropionic acids as potent agonists of sphingosine-1-phosphate receptor-1 (S1P1) with high selectivity against all other known S1P receptor subtypes.

    PubMed

    Yan, Lin; Huo, Pei; Doherty, George; Toth, Lesile; Hale, Jeffrey J; Mills, Sander G; Hajdu, Richard; Keohane, Carol A; Rosenbach, Mark J; Milligan, James A; Shei, Gan-Ju; Chrebet, Gary; Bergstrom, James; Card, Deborah; Quackenbush, Elizabeth; Wickham, Alexandra; Mandala, Suzanne M

    2006-07-15

    A series of 3-arylpropionic acids were synthesized as S1P1 receptor agonists. Structure-activity relationship studies on the pendant phenyl ring revealed several structural features offering selectivity of S1P1 binding against S1P2-5. These highly selective S1P1 agonists induced peripheral blood lymphocyte lowering in mice and one of them was found to be efficacious in a rat skin transplantation model, supporting that S1P1 agonism is primarily responsible for the immunosuppressive efficacy observed in preclinical animal models.

  14. Design and synthesis of conformationally constrained 3-(N-alkylamino)propylphosphonic acids as potent agonists of sphingosine-1-phosphate (S1P) receptors.

    PubMed

    Yan, Lin; Hale, Jeffrey J; Lynch, Christopher L; Budhu, Richard; Gentry, Amy; Mills, Sander G; Hajdu, Richard; Keohane, Carol Ann; Rosenbach, Mark J; Milligan, James A; Shei, Gan-Ju; Chrebet, Gary; Bergstrom, James; Card, Deborah; Rosen, Hugh; Mandala, Suzanne M

    2004-10-01

    A series of conformationally constrained 3-(N-alkylamino)propylphosphonic acids were systematically synthesized and their activities as S1P receptor agonists were evaluated. Several pyrrolidine and cyclohexane analogs had S1P receptor profiles comparable to the acyclic lead compound, 3-(N-tetradecylamino)propylphosphonic acid (3), lowered circulating lymphocytes in mice after iv administration and were thus identified as being suitable for further investigations.

  15. Sphingosine 1-phosphate receptor 2 (S1P2) attenuates reactive oxygen species formation and inhibits cell death: implications for otoprotective therapy.

    PubMed

    Herr, Deron R; Reolo, Marie J Y; Peh, Yee Xin; Wang, Wei; Lee, Chang-Wook; Rivera, Rich; Paterson, Ian C; Chun, Jerold

    2016-04-15

    Ototoxic drugs, such as platinum-based chemotherapeutics, often lead to permanent hearing loss through apoptosis of neuroepithelial hair cells and afferent neurons of the cochlea. There is no approved therapy for preventing or reversing this process. Our previous studies identified a G protein-coupled receptor (GPCR), S1P2, as a potential mediator of otoprotection. We therefore sought to identify a pharmacological approach to prevent cochlear degeneration via activation of S1P2. The cochleae of S1pr2(-/-) knockout mice were evaluated for accumulation of reactive oxygen species (ROS) with a nitro blue tetrazolium (NBT) assay. This showed that loss of S1P2 results in accumulation of ROS that precedes progressive cochlear degeneration as previously reported. These findings were supported by in vitro cell-based assays to evaluate cell viability, induction of apoptosis, and accumulation of ROS following activation of S1P2 in the presence of cisplatin. We show for the first time, that activation of S1P2 with a selective receptor agonist increases cell viability and reduces cisplatin-mediated cell death by reducing ROS. Cumulatively, these results suggest that S1P2 may serve as a therapeutic target for attenuating cisplatin-mediated ototoxicity.

  16. Sphingosine 1-phosphate receptor 2 (S1P2) attenuates reactive oxygen species formation and inhibits cell death: implications for otoprotective therapy

    PubMed Central

    Herr, Deron R.; Reolo, Marie J. Y.; Peh, Yee Xin; Wang, Wei; Lee, Chang-Wook; Rivera, Rich; Paterson, Ian C.; Chun, Jerold

    2016-01-01

    Ototoxic drugs, such as platinum-based chemotherapeutics, often lead to permanent hearing loss through apoptosis of neuroepithelial hair cells and afferent neurons of the cochlea. There is no approved therapy for preventing or reversing this process. Our previous studies identified a G protein-coupled receptor (GPCR), S1P2, as a potential mediator of otoprotection. We therefore sought to identify a pharmacological approach to prevent cochlear degeneration via activation of S1P2. The cochleae of S1pr2−/− knockout mice were evaluated for accumulation of reactive oxygen species (ROS) with a nitro blue tetrazolium (NBT) assay. This showed that loss of S1P2 results in accumulation of ROS that precedes progressive cochlear degeneration as previously reported. These findings were supported by in vitro cell-based assays to evaluate cell viability, induction of apoptosis, and accumulation of ROS following activation of S1P2 in the presence of cisplatin. We show for the first time, that activation of S1P2 with a selective receptor agonist increases cell viability and reduces cisplatin-mediated cell death by reducing ROS. Cumulatively, these results suggest that S1P2 may serve as a therapeutic target for attenuating cisplatin-mediated ototoxicity. PMID:27080739

  17. Involvement of sphingosine-1-phosphate and S1P1 in angiogenesis: analyses using a new S1P1 antagonist of non-sphingosine-1-phosphate analog.

    PubMed

    Yonesu, Kiyoaki; Kawase, Yumi; Inoue, Tatsuya; Takagi, Nana; Tsuchida, Jun; Takuwa, Yoh; Kumakura, Seiichiro; Nara, Futoshi

    2009-03-15

    Chemical lead 2 (CL2) is the first non-sphingosine-1-phosphate (Sph-1-P) analog type antagonist of endothelial differentiation gene-1 (Edg-1/S1P(1)), which is a member of the Sph-1-P receptor family. CL2 inhibits [(3)H]Sph-1-P/S1P(1) binding and shows concentration-dependent inhibition activity against both intracellular cAMP concentration decrease and cell invasion induced by the Sph-1-P/S1P(1) pathway. It also inhibits normal tube formation in an angiogenesis culture model, indicating that CL2 has anti-angiogenesis activity. This compound improved the disease conditions in two angiogenic models in vivo. It significantly inhibited angiogenesis induced by vascular endothelial growth factor in a rabbit cornea model as well as the swelling of mouse feet in an anti-type II collagen antibody-induced arthritis model. These results indicate that the Sph-1-P/S1P(1) pathway would have an important role in disease-related angiogenesis, especially in the processes of migration/invasion and tube formation. In addition, CL2 would be a powerful tool for the pharmacological study of the mechanisms of the Sph-1-P/S1P(1) pathway in rheumatoid arthritis, diabetes retinopathy, and solid tumor growth processes. PMID:19150609

  18. Transforming growth factor β2 (TGF-β2)-induced connective tissue growth factor (CTGF) expression requires sphingosine 1-phosphate receptor 5 (S1P5) in human mesangial cells.

    PubMed

    Wünsche, Christin; Koch, Alexander; Goldschmeding, Roel; Schwalm, Stephanie; Meyer Zu Heringdorf, Dagmar; Huwiler, Andrea; Pfeilschifter, Josef

    2015-05-01

    Transforming growth factor β2 (TGF-β2) is well known to stimulate the expression of pro-fibrotic connective tissue growth factor (CTGF) in several cell types including human mesangial cells. The present study demonstrates that TGF-β2 enhances sphingosine 1-phosphate receptor 5 (S1P5) mRNA and protein expression in a time and concentration dependent manner. Pharmacological and siRNA approaches reveal that this upregulation is mediated via activation of classical TGF-β downstream effectors, Smad and mitogen-activated protein kinases. Most notably, inhibition of Gi with pertussis toxin and downregulation of S1P5 by siRNA block TGF-β2-stimulated upregulation of CTGF, demonstrating that Gi coupled S1P5 is necessary for TGF-β2-triggered expression of CTGF in human mesangial cells. Overall, these findings indicate that TGF-β2 dependent upregulation of S1P5 is required for the induction of pro-fibrotic CTGF by TGF-β. Targeting S1P5 might be an attractive novel approach to treat renal fibrotic diseases.

  19. SAR studies of 3-arylpropionic acids as potent and selective agonists of sphingosine-1-phosphate receptor-1 (S1P1) with enhanced pharmacokinetic properties.

    PubMed

    Yan, Lin; Huo, Pei; Hale, Jeffrey J; Mills, Sander G; Hajdu, Richard; Keohane, Carol A; Rosenbach, Mark J; Milligan, James A; Shei, Gan-Ju; Chrebet, Gary; Bergstrom, James; Card, Deborah; Mandala, Suzanne M

    2007-02-01

    Structure-activity relationship (SAR) studies of 3-arylpropionic acids-a class of novel S1P(1) selective agonists-by introducing substitution to the propionic acid chain and replacing the adjacent phenyl ring with pyridine led to a series of modified 3-arylpropionic acids with enhanced half-life in rat. These analogs (e.g., cyclopropanecarboxylic acids) exhibited longer half-life in rat than did unmodified 3-arylpropionic acids. This result suggests that metabolic oxidation at the propionic acid chain, particularly at the C3 benzylic position of 3-arylpropionic acids, is probably responsible for their short half-life in rodent.

  20. Atheroprotective role of high-density lipoprotein (HDL)-associated sphingosine-1-phosphate (S1P).

    PubMed

    Potì, Francesco; Simoni, Manuela; Nofer, Jerzy-Roch

    2014-08-01

    Numerous epidemiological studies documented an inverse relationship between plasma high-density lipoprotein (HDL) cholesterol levels and the extent of atherosclerotic disease. However, clinical interventions targeting HDL cholesterol failed to show clinical benefits with respect to cardiovascular risk reduction, suggesting that HDL components distinct from cholesterol may account for anti-atherogenic effects attributed to this lipoprotein. Sphingosine-1-phosphate (S1P)-a lysosphingolipid exerting its biological activity via binding to specific G protein-coupled receptors and regulating a wide array of biological responses in a variety of different organs and tissues including the cardiovascular system-has been identified as an integral constituent of HDL particles. In the present review, we discuss current evidence from epidemiological studies, experimental approaches in vitro, and animal models of atherosclerosis, suggesting that S1P contributes to atheroprotective effects exerted by HDL particles. PMID:24891400

  1. Involvement of sphingosine 1-phosphate (SIP)/S1P3 signaling in cholestasis-induced liver fibrosis.

    PubMed

    Li, Changyong; Jiang, Xiangming; Yang, Lin; Liu, Xihong; Yue, Shi; Li, Liying

    2009-10-01

    Bioactive sphingosine 1-phosphate (S1P) and S1P receptors (S1PRs) have been implicated in many critical cellular events, including inflammation, cancer, and angiogenesis. However, the role of S1P/S1PR signaling in the pathogenesis of liver fibrosis has not been well documented. In this study, we found that S1P levels and S1P(3) receptor expression in liver tissue were markedly up-regulated in a mouse model of cholestasis-induced liver fibrosis. In addition, the S1P(3) receptor was also expressed in green fluorescent protein transgenic bone marrow (BM)-derived cells found in the damaged liver of transplanted chimeric mice that underwent bile duct ligation. Silencing of S1P(3) expression significantly inhibited S1P-induced BM cell migration in vitro. Furthermore, a selective S1P(3) receptor antagonist, suramin, markedly reduced the number of BM-derived cells during cholestasis. Interestingly, suramin administration clearly ameliorated bile duct ligation-induced hepatic fibrosis, as demonstrated by attenuated deposition of collagen type I and III, reduced smooth muscle alpha-actin expression, and decreased total hydroxyproline content. In conclusion, our data suggest that S1P/S1P(3) signaling plays an important role in cholestasis-induced liver fibrosis through mediating the homing of BM cells. Modulation of S1PR activity may therefore represent a new antifibrotic strategy.

  2. Sphingosine 1-phosphate to p38 signaling via S1P1 receptor and Gαi/o evokes augmentation of capsaicin-induced ionic currents in mouse sensory neurons.

    PubMed

    Langeslag, Michiel; Quarta, Serena; Leitner, Michael G; Kress, Michaela; Mair, Norbert

    2014-01-01

    The perception of painful thermal stimuli by sensory neurons is largely mediated by TRPV1. Upon tissue injury or inflammation, S1P is secreted by thrombocytes as part of an inflammatory cocktail, which sensitizes nociceptive neurons towards thermal stimuli. S1P acts on G-protein coupled receptors that are expressed in sensory neurons and sensitize TRPV1 channels towards thermal stimuli. In this study, the S1P mediated signaling pathway required for sensitization of TRPV1 channels was explored.The capsaicin induced peak inward current (ICAPS) of sensory neurons was significantly increased after S1P stimulation within minutes after application. The potentiation of ICAPS resulted from activation of Gαi through G-protein coupled receptors for S1P. Consequently, Gαi led to a signaling cascade, involving phosphoinositide-3-kinase (PI3K) and protein kinase C, which augmented ICAPS in nociceptive neurons. The S1P1 receptor agonist SEW2871 resulted in activation of the same signaling pathway and potentiation of ICAPS. Furthermore, the mitogen-activated protein kinase p38 was phosphorylated after S1P stimulation and inhibition of p38 signaling by SB203580 prevented the S1P-induced ICAPS potentiation. The current data suggest that S1P sensitized ICAPS through G-protein coupled S1P1 receptor activation of Gαi-PI3K-PKC-p38 signaling pathway in sensory neurons. PMID:25431213

  3. Blocking S1P interaction with S1P{sub 1} receptor by a novel competitive S1P{sub 1}-selective antagonist inhibits angiogenesis

    SciTech Connect

    Fujii, Yasuyuki; Ueda, Yasuji; Ohtake, Hidenori; Ono, Naoya; Takayama, Tetsuo; Nakazawa, Kiyoshi; Igarashi, Yasuyuki; Goitsuka, Ryo

    2012-03-23

    Highlights: Black-Right-Pointing-Pointer The effect of a newly developed S1P{sub 1}-selective antagonist on angiogenic responses. Black-Right-Pointing-Pointer S1P{sub 1} is a critical component of VEGF-related angiogenic responses. Black-Right-Pointing-Pointer S1P{sub 1}-selective antagonist showed in vitro activity to inhibit angiogenesis. Black-Right-Pointing-Pointer S1P{sub 1}-selective antagonist showed in vivo activity to inhibit angiogenesis. Black-Right-Pointing-Pointer The efficacy of S1P{sub 1}-selective antagonist for anti-cancer therapies. -- Abstract: Sphingosine 1-phosphate receptor type 1 (S1P{sub 1}) was shown to be essential for vascular maturation during embryonic development and it has been demonstrated that substantial crosstalk exists between S1P{sub 1} and other pro-angiogenic growth factors, such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor. We developed a novel S1P{sub 1}-selective antagonist, TASP0277308, which is structurally unrelated to S1P as well as previously described S1P{sub 1} antagonists. TASP0277308 inhibited S1P- as well as VEGF-induced cellular responses, including migration and proliferation of human umbilical vein endothelial cells. Furthermore, TASP0277308 effectively blocked a VEGF-induced tube formation in vitro and significantly suppressed tumor cell-induced angiogenesis in vivo. These findings revealed that S1P{sub 1} is a critical component of VEGF-related angiogenic responses and also provide evidence for the efficacy of TASP0277308 for anti-cancer therapies.

  4. Sphingosine-1-Phosphate Induces Dose-Dependent Chemotaxis or Fugetaxis of T-ALL Blasts through S1P1 Activation

    PubMed Central

    Messias, Carolina V.; Santana-Van-Vliet, Eliane; Lemos, Julia P.; Moreira, Otacilio C.; Cotta-de-Almeida, Vinicius; Savino, Wilson; Mendes-da-Cruz, Daniella Arêas

    2016-01-01

    Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid involved in several physiological processes including cell migration and differentiation. S1P signaling is mediated through five G protein-coupled receptors (S1P1-S1P5). S1P1 is crucial to the exit of T-lymphocytes from the thymus and peripheral lymphoid organs through a gradient of S1P. We have previously observed that T-ALL and T-LBL blasts express S1P1. Herein we analyzed the role of S1P receptors in the migratory pattern of human T-cell neoplastic blasts. S1P-triggered cell migration was directly related to S1P1 expression. T-ALL blasts expressing low levels of S1P1 mRNA (HPB-ALL) did not migrate toward S1P, whereas those expressing higher levels of S1P1 (MOLT-4, JURKAT and CEM) did migrate. The S1P ligand induced T-ALL cells chemotaxis in concentrations up to 500 nM and induced fugetaxis in higher concentrations (1000–10000 nM) through interactions with S1P1. When S1P1 was specifically blocked by the W146 compound, S1P-induced migration at lower concentrations was reduced, whereas higher concentrations induced cell migration. Furthermore, we observed that S1P/S1P1 interactions induced ERK and AKT phosphorylation, and modulation of Rac1 activity. Responding T-ALL blasts also expressed S1P3 mRNA but blockage of this receptor did not modify migratory responses. Our results indicate that S1P is involved in the migration of T-ALL/LBL blasts, which is dependent on S1P1 expression. Moreover, S1P concentrations in the given microenvironment might induce dose-dependent chemotaxis or fugetaxis of T-ALL blasts. PMID:26824863

  5. Sphingosine-1-Phosphate Induces Dose-Dependent Chemotaxis or Fugetaxis of T-ALL Blasts through S1P1 Activation.

    PubMed

    Messias, Carolina V; Santana-Van-Vliet, Eliane; Lemos, Julia P; Moreira, Otacilio C; Cotta-de-Almeida, Vinicius; Savino, Wilson; Mendes-da-Cruz, Daniella Arêas

    2016-01-01

    Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid involved in several physiological processes including cell migration and differentiation. S1P signaling is mediated through five G protein-coupled receptors (S1P1-S1P5). S1P1 is crucial to the exit of T-lymphocytes from the thymus and peripheral lymphoid organs through a gradient of S1P. We have previously observed that T-ALL and T-LBL blasts express S1P1. Herein we analyzed the role of S1P receptors in the migratory pattern of human T-cell neoplastic blasts. S1P-triggered cell migration was directly related to S1P1 expression. T-ALL blasts expressing low levels of S1P1 mRNA (HPB-ALL) did not migrate toward S1P, whereas those expressing higher levels of S1P1 (MOLT-4, JURKAT and CEM) did migrate. The S1P ligand induced T-ALL cells chemotaxis in concentrations up to 500 nM and induced fugetaxis in higher concentrations (1000-10000 nM) through interactions with S1P1. When S1P1 was specifically blocked by the W146 compound, S1P-induced migration at lower concentrations was reduced, whereas higher concentrations induced cell migration. Furthermore, we observed that S1P/S1P1 interactions induced ERK and AKT phosphorylation, and modulation of Rac1 activity. Responding T-ALL blasts also expressed S1P3 mRNA but blockage of this receptor did not modify migratory responses. Our results indicate that S1P is involved in the migration of T-ALL/LBL blasts, which is dependent on S1P1 expression. Moreover, S1P concentrations in the given microenvironment might induce dose-dependent chemotaxis or fugetaxis of T-ALL blasts. PMID:26824863

  6. Potent and Selective Agonists of Sphingosine 1-Phosphate 1 (S1P1): Discovery and SAR of a Novel Isoxazole Based Series.

    PubMed

    Watterson, Scott H; Guo, Junqing; Spergel, Steve H; Langevine, Charles M; Moquin, Robert V; Shen, Ding Ren; Yarde, Melissa; Cvijic, Mary Ellen; Banas, Dana; Liu, Richard; Suchard, Suzanne J; Gillooly, Kathleen; Taylor, Tracy; Rex-Rabe, Sandra; Shuster, David J; McIntyre, Kim W; Cornelius, Georgia; D'Arienzo, Celia; Marino, Anthony; Balimane, Praveen; Warrack, Bethanne; Salter-Cid, Luisa; McKinnon, Murray; Barrish, Joel C; Carter, Percy H; Pitts, William J; Xie, Jenny; Dyckman, Alaric J

    2016-03-24

    Sphingosine 1-phosphate (S1P) is the endogenous ligand for the sphingosine 1-phosphate receptors (S1P1-5) and evokes a variety of cellular responses through their stimulation. The interaction of S1P with the S1P receptors plays a fundamental physiological role in a number of processes including vascular development and stabilization, lymphocyte migration, and proliferation. Agonism of S1P1, in particular, has been shown to play a significant role in lymphocyte trafficking from the thymus and secondary lymphoid organs, resulting in immunosuppression. This article will detail the discovery and SAR of a potent and selective series of isoxazole based full agonists of S1P1. Isoxazole 6d demonstrated impressive efficacy when administered orally in a rat model of arthritis and in a mouse experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis. PMID:26924461

  7. Exogenous S1P Exposure Potentiates Ischemic Stroke Damage That Is Reduced Possibly by Inhibiting S1P Receptor Signaling

    PubMed Central

    Moon, Eunjung; Han, Jeong Eun; Jeon, Sejin; Ryu, Jong Hoon; Choi, Ji Woong; Chun, Jerold

    2015-01-01

    Initial and recurrent stroke produces central nervous system (CNS) damage, involving neuroinflammation. Receptor-mediated S1P signaling can influence neuroinflammation and has been implicated in cerebral ischemia through effects on the immune system. However, S1P-mediated events also occur within the brain itself where its roles during stroke have been less well studied. Here we investigated the involvement of S1P signaling in initial and recurrent stroke by using a transient middle cerebral artery occlusion/reperfusion (M/R) model combined with analyses of S1P signaling. Gene expression for S1P receptors and involved enzymes was altered during M/R, supporting changes in S1P signaling. Direct S1P microinjection into the normal CNS induced neuroglial activation, implicating S1P-initiated neuroinflammatory responses that resembled CNS changes seen during initial M/R challenge. Moreover, S1P microinjection combined with M/R potentiated brain damage, approximating a model for recurrent stroke dependent on S1P and suggesting that reduction in S1P signaling could ameliorate stroke damage. Delivery of FTY720 that removes S1P signaling with chronic exposure reduced damage in both initial and S1P-potentiated M/R-challenged brain, while reducing stroke markers like TNF-α. These results implicate direct S1P CNS signaling in the etiology of initial and recurrent stroke that can be therapeutically accessed by S1P modulators acting within the brain. PMID:26576074

  8. Expression of S1P metabolizing enzymes and receptors correlate with survival time and regulate cell migration in glioblastoma multiforme

    PubMed Central

    Bien-Möller, Sandra; Lange, Sandra; Holm, Tobias; Böhm, Andreas; Paland, Heiko; Küpper, Johannes; Herzog, Susann; Weitmann, Kerstin; Havemann, Christoph; Vogelgesang, Silke; Marx, Sascha; Hoffmann, Wolfgang; Schroeder, Henry W.S.; Rauch, Bernhard H.

    2016-01-01

    A signaling molecule which is involved in proliferation and migration of malignant cells is the lipid mediator sphingosine-1-phosphate (S1P). There are hints for a potential role of S1P signaling in malignant brain tumors such as glioblastoma multiforme (GBM) which is characterized by a poor prognosis. Therefore, a comprehensive expression analysis of S1P receptors (S1P1-S1P5) and S1P metabolizing enzymes in human GBM (n = 117) compared to healthy brain (n = 10) was performed to evaluate their role for patient's survival. Furthermore, influence of S1P receptor inhibition on proliferation and migration were studied in LN18 GBM cells. Compared to control brain, mRNA levels of S1P1, S1P2, S1P3 and S1P generating sphingosine kinase-1 were elevated in GBM. Kaplan-Meier analyses demonstrated an association between S1P1 and S1P2 with patient's survival times. In vitro, an inhibitory effect of the SphK inhibitor SKI-II on viability of LN18 cells was shown. S1P itself had no effect on viability but stimulated LN18 migration which was blocked by inhibition of S1P1 and S1P2. The participation of S1P1 and S1P2 in LN18 migration was further supported by siRNA-mediated silencing of these receptors. Immunoblots and inhibition experiments suggest an involvement of the PI3-kinase/AKT1 pathway in the chemotactic effect of S1P in LN18 cells. In summary, our data argue for a role of S1P signaling in proliferation and migration of GBM cells. Individual components of the S1P pathway represent prognostic factors for patients with GBM. Perspectively, a selective modulation of S1P receptor subtypes could represent a therapeutic approach for GBM patients and requires further evaluation. PMID:26887055

  9. Genetic Evidence for Involvement of Neuronally Expressed S1P1 Receptor in Nociceptor Sensitization and Inflammatory Pain

    PubMed Central

    Mair, Norbert; Benetti, Camilla; Andratsch, Manfred; Leitner, Michael G.; Constantin, Cristina E.; Camprubí-Robles, Maria; Quarta, Serena; Biasio, Wolfgang; Kuner, Rohini; Gibbins, Ian L.; Kress, Michaela; Haberberger, Rainer V.

    2011-01-01

    Sphingosine-1-phosphate (S1P) is a key regulator of immune response. Immune cells, epithelia and blood cells generate high levels of S1P in inflamed tissue. However, it is not known if S1P acts on the endings of nociceptive neurons, thereby contributing to the generation of inflammatory pain. We found that the S1P1 receptor for S1P is expressed in subpopulations of sensory neurons including nociceptors. Both S1P and agonists at the S1P1 receptor induced hypersensitivity to noxious thermal stimulation in vitro and in vivo. S1P-induced hypersensitivity was strongly attenuated in mice lacking TRPV1 channels. S1P and inflammation-induced hypersensitivity was significantly reduced in mice with a conditional nociceptor-specific deletion of the S1P1 receptor. Our data show that neuronally expressed S1P1 receptors play a significant role in regulating nociceptor function and that S1P/S1P1 signaling may be a key player in the onset of thermal hypersensitivity and hyperalgesia associated with inflammation. PMID:21359147

  10. Synthesis of fluorinated agonist of sphingosine-1-phosphate receptor 1.

    PubMed

    Aliouane, Lucie; Chao, Sovy; Brizuela, Leyre; Pfund, Emmanuel; Cuvillier, Olivier; Jean, Ludovic; Renard, Pierre-Yves; Lequeux, Thierry

    2014-09-01

    The bioactive metabolite sphingosine-1-phosphate (S1P), a product of sphingosine kinases (SphKs), mediates diverse biological processes such as cell differentiation, proliferation, survival and angiogenesis. A fluorinated analogue of S1P receptor agonist has been synthesized by utilizing a ring opening reaction of oxacycles by a lithiated difluoromethylphosphonate anion as the key reaction. In vitro activity of this S1P analogue is also reported.

  11. Mesenchymal Stromal Cell Secreted Sphingosine 1-Phosphate (S1P) Exerts a Stimulatory Effect on Skeletal Myoblast Proliferation

    PubMed Central

    Tani, Alessia; Anderloni, Giulia; Pierucci, Federica; Matteini, Francesca; Chellini, Flaminia; Zecchi Orlandini, Sandra; Meacci, Elisabetta

    2014-01-01

    Bone-marrow-derived mesenchymal stromal cells (MSCs) have the potential to significantly contribute to skeletal muscle healing through the secretion of paracrine factors that support proliferation and enhance participation of the endogenous muscle stem cells in the process of repair/regeneration. However, MSC-derived trophic molecules have been poorly characterized. The aim of this study was to investigate paracrine signaling effects of MSCs on skeletal myoblasts. It was found, using a biochemical and morphological approach that sphingosine 1-phosphate (S1P), a natural bioactive lipid exerting a broad range of muscle cell responses, is secreted by MSCs and represents an important factor by which these cells exert their stimulatory effects on C2C12 myoblast and satellite cell proliferation. Indeed, exposure to conditioned medium obtained from MSCs cultured in the presence of the selective sphingosine kinase inhibitor (iSK), blocked increased cell proliferation caused by the conditioned medium from untreated MSCs, and the addition of exogenous S1P in the conditioned medium from MSCs pre-treated with iSK further increased myoblast proliferation. Finally, we also demonstrated that the myoblast response to MSC-secreted vascular endothelial growth factor (VEGF) involves the release of S1P from C2C12 cells. Our data may have important implications in the optimization of cell-based strategies to promote skeletal muscle regeneration. PMID:25264785

  12. A practical process for the preparation of [32P]S1P and binding assay for S1P receptor ligands

    PubMed Central

    Rosenberg, Adam J.; Liu, Hui; Tu, Zhude

    2015-01-01

    Sphingosine-1-phosphate receptors (S1PRs) are important regulators of vascular permeability, inflammation, angiogenesis and vascular maturation. Identifying a specific S1PR PET radioligand is imperative, but it is hindered by the complexity and variability of current for binding affinity measurement procedures. Herein, we report a streamlined protocol for radiosynthesis of [32P]S1P with good radiochemical yield (36 – 50%) and high radiochemical purity (>99%). We also report a reproducible procedure for determining the binding affinity for compounds targeting S1PRs in vitro. PMID:25931137

  13. Potential Link between the Sphingosine-1-Phosphate (S1P) System and Defective Alveolar Macrophage Phagocytic Function in Chronic Obstructive Pulmonary Disease (COPD)

    PubMed Central

    Barnawi, Jameel; Tran, Hai; Jersmann, Hubertus; Pitson, Stuart; Roscioli, Eugene; Hodge, Greg; Meech, Robyn; Haberberger, Rainer; Hodge, Sandra

    2015-01-01

    Introduction We previously reported that alveolar macrophages from patients with chronic obstructive pulmonary disease (COPD) are defective in their ability to phagocytose apoptotic cells, with a similar defect in response to cigarette smoke. The exact mechanisms for this defect are unknown. Sphingolipids including ceramide, sphingosine and sphingosine-1-phosphate (S1P) are involved in diverse cellular processes and we hypothesised that a comprehensive analysis of this system in alveolar macrophages in COPD may help to delineate the reasons for defective phagocytic function. Methods We compared mRNA expression of sphingosine kinases (SPHK1/2), S1P receptors (S1PR1-5) and S1P-degrading enzymes (SGPP1, SGPP2, SGPL1) in bronchoalveolar lavage-derived alveolar macrophages from 10 healthy controls, 7 healthy smokers and 20 COPD patients (10 current- and 10 ex-smokers) using Real-Time PCR. Phagocytosis of apoptotic cells was investigated using flow cytometry. Functional associations were assessed between sphingosine signalling system components and alveolar macrophage phagocytic ability in COPD. To elucidate functional effects of increased S1PR5 on macrophage phagocytic ability, we performed the phagocytosis assay in the presence of varying concentrations of suramin, an antagonist of S1PR3 and S1PR5. The effects of cigarette smoking on the S1P system were investigated using a THP-1 macrophage cell line model. Results We found significant increases in SPHK1/2 (3.4- and 2.1-fold increases respectively), S1PR2 and 5 (4.3- and 14.6-fold increases respectively), and SGPL1 (4.5-fold increase) in COPD vs. controls. S1PR5 and SGPL1 expression was unaffected by smoking status, suggesting a COPD “disease effect” rather than smoke effect per se. Significant associations were noted between S1PR5 and both lung function and phagocytosis. Cigarette smoke extract significantly increased mRNA expression of SPHK1, SPHK2, S1PR2 and S1PR5 by THP-1 macrophages, confirming the results in

  14. Uncleaved ApoM Signal Peptide Is Required for Formation of Large ApoM/Sphingosine 1-Phosphate (S1P)-enriched HDL Particles*

    PubMed Central

    Liu, Mingxia; Allegood, Jeremy; Zhu, Xuewei; Seo, Jeongmin; Gebre, Abraham K.; Boudyguina, Elena; Cheng, Dongmei; Chuang, Chia-Chi; Shelness, Gregory S.; Spiegel, Sarah; Parks, John S.

    2015-01-01

    Apolipoprotein M (apoM), a plasma sphingosine 1-phosphate (S1P) carrier, associates with plasma HDL via its uncleaved signal peptide. Hepatocyte-specific apoM overexpression in mice stimulates formation of both larger nascent HDL in hepatocytes and larger mature apoM/S1P-enriched HDL particles in plasma by enhancing hepatic S1P synthesis and secretion. Mutagenesis of apoM glutamine 22 to alanine (apoMQ22A) introduces a functional signal peptidase cleavage site. Expression of apoMQ22A in ABCA1-expressing HEK293 cells resulted in the formation of smaller nascent HDL particles compared with wild type apoM (apoMWT). When apoMQ22A was expressed in vivo, using recombinant adenoviruses, smaller plasma HDL particles and decreased plasma S1P and apoM were observed relative to expression of apoMWT. Hepatocytes isolated from both apoMWT- and apoMQ22A-expressing mice displayed an equivalent increase in cellular levels of S1P, relative to LacZ controls; however, relative to apoMWT, apoMQ22A hepatocytes displayed more rapid apoM and S1P secretion but minimal apoMQ22A bound to nascent lipoproteins. Pharmacologic inhibition of ceramide synthesis increased cellular sphingosine and S1P but not medium S1P in both apoMWT and apoMQ22A hepatocytes. We conclude that apoM secretion is rate-limiting for hepatocyte S1P secretion and that its uncleaved signal peptide delays apoM trafficking out of the cell, promoting formation of larger nascent apoM- and S1P-enriched HDL particles that are probably precursors of larger apoM/S1P-enriched plasma HDL. PMID:25627684

  15. Sphingosine phosphate lyase regulates myogenic differentiation via S1P receptor-mediated effects on myogenic microRNA expression.

    PubMed

    de la Garza-Rodea, Anabel S; Baldwin, Dianna M; Oskouian, Babak; Place, Robert F; Bandhuvula, Padmavathi; Kumar, Ashok; Saba, Julie D

    2014-01-01

    S1P lyase (SPL) catalyzes the irreversible degradation of sphingosine-1-phosphate (S1P), a bioactive lipid whose signaling activities regulate muscle differentiation, homeostasis, and satellite cell (SC) activation. By regulating S1P levels, SPL also controls SC recruitment and muscle regeneration, representing a potential therapeutic target for muscular dystrophy. We found that SPL is induced during myoblast differentiation. To investigate SPL's role in myogenesis at the cellular level, we generated and characterized a murine myoblast SPL-knockdown (SPL-KD) cell line lacking SPL. SPL-KD cells accumulated intracellular and extracellular S1P and failed to form myotubes under conditions that normally stimulate myogenic differentiation. Under differentiation conditions, SPL-KD cells also demonstrated delayed induction of 3 myogenic microRNAs (miRNAs), miR-1, miR-206, and miR-486. SPL-KD cells successfully differentiated when treated with an S1P1 agonist, S1P2 antagonist, and combination treatments, which also increased myogenic miRNA levels. SPL-KD cells transfected with mimics for miR-1 or miR-206 also overcame the differentiation block. Thus, we show for the first time that the S1P/SPL/S1P-receptor axis regulates the expression of a number of miRNAs, thereby contributing to myogenic differentiation.

  16. Sphingosine-1-Phosphate Receptor-2 Antagonists: Therapeutic Potential and Potential Risks

    PubMed Central

    Blankenbach, Kira V.; Schwalm, Stephanie; Pfeilschifter, Josef; Meyer zu Heringdorf, Dagmar

    2016-01-01

    The sphingosine-1-phosphate (S1P) signaling system with its specific G-protein-coupled S1P receptors, the enzymes of S1P metabolism and the S1P transporters, offers a multitude of promising targets for drug development. Until today, drug development in this area has nearly exclusively focused on (functional) antagonists at the S1P1 receptor, which cause a unique phenotype of immunomodulation. Accordingly, the first-in class S1P1 receptor modulator, fingolimod, has been approved for the treatment of relapsing-remitting multiple sclerosis, and novel S1P1 receptor (functional) antagonists are being developed for autoimmune and inflammatory diseases such as psoriasis, inflammatory bowel disease, lupus erythematodes, or polymyositis. Besides the S1P1 receptor, also S1P2 and S1P3 are widely expressed and regulate many diverse functions throughout the body. The S1P2 receptor, in particular, often exerts cellular functions which are opposed to the functions of the S1P1 receptor. As a consequence, antagonists at the S1P2 receptor have the potential to be useful in a contrasting context and different areas of indication compared to S1P1 antagonists. The present review will focus on the therapeutic potential of S1P2 receptor antagonists and discuss their opportunities as well as their potential risks. Open questions and areas which require further investigations will be emphasized in particular. PMID:27445808

  17. Selecting against S1P3 enhances the acute cardiovascular tolerability of 3-(N-benzyl)aminopropylphosphonic acid S1P receptor agonists.

    PubMed

    Hale, Jeffrey J; Doherty, George; Toth, Leslie; Mills, Sander G; Hajdu, Richard; Keohane, Carol Ann; Rosenbach, Mark; Milligan, James; Shei, Gan-Ju; Chrebet, Gary; Bergstrom, James; Card, Deborah; Forrest, Michael; Sun, Shu-Yu; West, Sarah; Xie, Huijuan; Nomura, Naomi; Rosen, Hugh; Mandala, Suzanne

    2004-07-01

    Structurally modified 3-(N-benzylamino)propylphosphonic acid S1P receptor agonists that maintain affinity for S1P1, and have decreased affinity for S1P3 are efficacious, but exhibit decreased acute cardiovascular toxicity in rodents than do nonselective agonists.

  18. Sphingosine-1-phosphate receptor 1 reporter mice reveal receptor activation sites in vivo

    PubMed Central

    Kono, Mari; Tucker, Ana E.; Tran, Jennifer; Bergner, Jennifer B.; Turner, Ewa M.; Proia, Richard L.

    2014-01-01

    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. PMID:24667638

  19. Modulators of the Sphingosine 1-phosphate receptor 1.

    PubMed

    Urbano, Mariangela; Guerrero, Miguel; Rosen, Hugh; Roberts, Edward

    2013-12-01

    The Sphingosine 1-phosphate receptor (S1P-R) signaling system has proven to be of biological and medical importance in autoimmune settings. S1P1-R is a validated drug target for multiple sclerosis (MS) for which FTY720 (Fingolimod), a S1P1,3-5-R pan-agonist, was recently approved as the first orally active drug for the treatment of relapsing-remitting MS. Transient bradycardia and long half-life are the FTY720 critical pitfalls. This review provides the latest advances on next-generation S1P1-R modulators from 2012 up to date, with an overview of the chemical structures, structure-activity relationships, and relevant biological and clinical properties.

  20. Regulation of human cerebro-microvascular endothelial baso-lateral adhesion and barrier function by S1P through dual involvement of S1P1 and S1P2 receptors.

    PubMed

    Wiltshire, Rachael; Nelson, Vicky; Kho, Dan Ting; Angel, Catherine E; O'Carroll, Simon J; Graham, E Scott

    2016-01-27

    Herein we show that S1P rapidly and acutely reduces the focal adhesion strength and barrier tightness of brain endothelial cells. xCELLigence biosensor technology was used to measure focal adhesion, which was reduced by S1P acutely and this response was mediated through both S1P1 and S1P2 receptors. S1P increased secretion of several pro-inflammatory mediators from brain endothelial cells. However, the magnitude of this response was small in comparison to that mediated by TNFα or IL-1β. Furthermore, S1P did not significantly increase cell-surface expression of any key cell adhesion molecules involved in leukocyte recruitment, included ICAM-1 and VCAM-1. Finally, we reveal that S1P acutely and dynamically regulates microvascular endothelial barrier tightness in a manner consistent with regulated rapid opening followed by closing and strengthening of the barrier. We hypothesise that the role of the S1P receptors in this process is not to cause barrier dysfunction, but is related to controlled opening of the endothelial junctions. This was revealed using real-time measurement of barrier integrity using ECIS ZΘ TEER technology and endothelial viability using xCELLigence technology. Finally, we show that these responses do not occur simply though the pharmacology of a single S1P receptor but involves coordinated action of S1P1 and S1P2 receptors.

  1. Sphingosine 1-Phosphate Receptor Modulators in Multiple Sclerosis

    PubMed Central

    Subei, Adnan M.

    2015-01-01

    Sphingosine 1-phosphate (S1P) receptor modulators possess a unique mechanism of action as disease modifying therapy for multiple sclerosis (MS). Subtype 1 S1P receptors are expressed on the surfaces of lymphocytes and are important in regulating egression from lymph nodes. The S1P receptor modulators indirectly antagonize the receptor’s function and sequester lymphocytes in lymph nodes. Fingolimod was the first S1P agent approved in the United States in 2010 for relapsing MS after two phase 3 trials (FREEDOMS and TRANSFORMS) demonstrated potent efficacy, and good safety and tolerability. Post-marketing experience as well as a third phase 3 trial (FREEDOMS II) also showed favorable results. More selective S1P receptor agents: ponesimod (ACT128800), siponimod (BAF312), ozanimod (RPC1063), ceralifimod (ONO-4641), GSK2018682, and MT-1303 are still in relatively early stages of development, but phase 1 and 2 trials showed promising efficacy and safety. However, these observations have yet to be reproduced in phase 3 clinical trials. PMID:26239599

  2. Late-stage optimization of a tercyclic class of S1P3-sparing, S1P1 receptor agonists.

    PubMed

    Horan, Joshua C; Kuzmich, Daniel; Liu, Pingrong; DiSalvo, Darren; Lord, John; Mao, Can; Hopkins, Tamara D; Yu, Hui; Harcken, Christian; Betageri, Raj; Hill-Drzewi, Melissa; Patenaude, Lori; Patel, Monica; Fletcher, Kimberly; Terenzzio, Donna; Linehan, Brian; Xia, Heather; Patel, Mita; Studwell, Debbie; Miller, Craig; Hickey, Eugene; Levin, Jeremy I; Smith, Dustin; Kemper, Raymond A; Modis, Louise K; Bannen, Lynne C; Chan, Diva S; Mac, Morrison B; Ng, Stephanie; Wang, Yong; Xu, Wei; Lemieux, René M

    2016-01-15

    Poor solubility and cationic amphiphilic drug-likeness were liabilities identified for a lead series of S1P3-sparing, S1P1 agonists originally developed from a high-throughput screening campaign. This work describes the subsequent optimization of these leads by balancing potency, selectivity, solubility and overall molecular charge. Focused SAR studies revealed favorable structural modifications that, when combined, produced compounds with overall balanced profiles. The low brain exposure observed in rat suggests that these compounds would be best suited for the potential treatment of peripheral autoimmune disorders. PMID:26687487

  3. Sphingosine-1-phosphate receptor 3 promotes leukocyte rolling by mobilizing endothelial P-selectin.

    PubMed

    Nussbaum, Claudia; Bannenberg, Sarah; Keul, Petra; Gräler, Markus H; Gonçalves-de-Albuquerque, Cassiano F; Korhonen, Hanna; von Wnuck Lipinski, Karin; Heusch, Gerd; de Castro Faria Neto, Hugo C; Rohwedder, Ina; Göthert, Joachim R; Prasad, Vysakh Pushpa; Haufe, Günter; Lange-Sperandio, Baerbel; Offermanns, Stefan; Sperandio, Markus; Levkau, Bodo

    2015-01-01

    Sphingosine-1-phosphate (S1P) participates in inflammation; however, its role in leukocyte rolling is still unclear. Here we use intravital microscopy in inflamed mouse cremaster muscle venules and human endothelial cells to show that S1P contributes to P-selectin-dependent leukocyte rolling through endothelial S1P receptor 3 (S1P3) and Gαq, PLCβ and Ca(2+). Intra-arterial S1P administration increases leukocyte rolling, while S1P3 deficiency or inhibition dramatically reduces it. Mast cells involved in triggering rolling also release S1P that mobilizes P-selectin through S1P3. Histamine and epinephrine require S1P3 for full-scale effect accomplishing it by stimulating sphingosine kinase 1 (Sphk1). In a counter-regulatory manner, S1P1 inhibits cAMP-stimulated Sphk1 and blocks rolling as observed in endothelial-specific S1P1(-/-) mice. In agreement with a dominant pro-rolling effect of S1P3, FTY720 inhibits rolling in control and S1P1(-/-) but not in S1P3(-/-) mice. Our findings identify S1P as a direct and indirect contributor to leukocyte rolling and characterize the receptors mediating its action.

  4. Sphingosine 1-phosphate counteracts insulin signaling in pancreatic β-cells via the sphingosine 1-phosphate receptor subtype 2.

    PubMed

    Japtok, Lukasz; Schmitz, Elisabeth I; Fayyaz, Susann; Krämer, Stephanie; Hsu, Leigh J; Kleuser, Burkhard

    2015-08-01

    Glucolipotoxic stress has been identified as a key player in the progression of pancreatic β-cell dysfunction contributing to insulin resistance and the development of type 2 diabetes mellitus (T2D). It has been suggested that bioactive lipid intermediates, formed under lipotoxic conditions, are involved in these processes. Here, we show that sphingosine 1-phosphate (S1P) levels are not only increased in palmitate-stimulated pancreatic β-cells but also regulate β-cell homeostasis in a divergent manner. Although S1P possesses a prosurvival effect in β-cells, an enhanced level of the sphingolipid antagonizes insulin-mediated cell growth and survival via the sphingosine 1-phosphate receptor subtype 2 (S1P2) followed by an inhibition of Akt-signaling. In an attempt to investigate the role of the S1P/S1P2 axis in vivo, the New Zealand obese (NZO) diabetic mouse model, characterized by β-cell loss under high-fat diet (HFD) conditions, was used. The occurrence of T2D was accompanied by an increase of plasma S1P levels. To examine whether S1P contributes to the morphologic changes of islets via S1P2, the receptor antagonist JTE-013 was administered. Most interestingly, JTE-013 rescued β-cell damage clearly indicating an important role of the S1P2 in β-cell homeostasis. Therefore, the present study provides a new therapeutic strategy to diminish β-cell dysfunction and the development of T2D. PMID:25911610

  5. Sphingosine-1-Phosphate and Its Receptors: A Mutual Link between Blood Coagulation and Inflammation

    PubMed Central

    Mahajan-Thakur, Shailaja; Böhm, Andreas; Jedlitschky, Gabriele; Schrör, Karsten; Rauch, Bernhard H.

    2015-01-01

    Sphingosine-1-phosphate (S1P) is a versatile lipid signaling molecule and key regulator in vascular inflammation. S1P is secreted by platelets, monocytes, and vascular endothelial and smooth muscle cells. It binds specifically to a family of G-protein-coupled receptors, S1P receptors 1 to 5, resulting in downstream signaling and numerous cellular effects. S1P modulates cell proliferation and migration, and mediates proinflammatory responses and apoptosis. In the vascular barrier, S1P regulates permeability and endothelial reactions and recruitment of monocytes and may modulate atherosclerosis. Only recently has S1P emerged as a critical mediator which directly links the coagulation factor system to vascular inflammation. The multifunctional proteases thrombin and FXa regulate local S1P availability and interact with S1P signaling at multiple levels in various vascular cell types. Differential expression patterns and intracellular signaling pathways of each receptor enable S1P to exert its widespread functions. Although a vast amount of information is available about the functions of S1P and its receptors in the regulation of physiological and pathophysiological conditions, S1P-mediated mechanisms in the vasculature remain to be elucidated. This review summarizes recent findings regarding the role of S1P and its receptors in vascular wall and blood cells, which link the coagulation system to inflammatory responses in the vasculature. PMID:26604433

  6. Enhanced Chemokine Receptor Recycling and Impaired S1P1 Expression Promote Leukemic Cell Infiltration of Lymph Nodes in Chronic Lymphocytic Leukemia.

    PubMed

    Patrussi, Laura; Capitani, Nagaja; Martini, Veronica; Pizzi, Marco; Trimarco, Valentina; Frezzato, Federica; Marino, Filippo; Semenzato, Gianpietro; Trentin, Livio; Baldari, Cosima T

    2015-10-01

    Lymphocyte trafficking is orchestrated by chemokine and sphingosine 1-phosphate (S1P) receptors that enable homing and egress from secondary lymphoid organs (SLO). These receptors undergo rapid internalization and plasma membrane recycling to calibrate cellular responses to local chemoattractants. Circulating chronic lymphocytic leukemia (CLL) cells display an abnormal increase in the surface levels of the homing receptors CCR7 and CXCR4 concomitant with low S1P receptor 1 (S1P1) expression. In this study, we investigated the role of receptor recycling on CXCR4/CCR7 surface levels in CLL cells and addressed the impact of quantitative alterations of these receptors and S1P1 on the ability of leukemic cells to accumulate in SLOs. We show that recycling accounts, to a major extent, for the high levels of surface CXCR4/CCR7 on CLL cells. In addition, increased expression of these receptors, together with S1P1 deficiency, is detectable not only in circulating leukemic cells, but also in SLOs of CLL patients with lymphoadenopathy. We further provide evidence that ibrutinib, a Btk inhibitor that promotes mobilization of leukemic cells from SLOs, normalizes the imbalance between CXCR4/CCR7 and S1P1. Taken together, our results highlight the relevance of chemokine and S1P receptor recycling in CLL pathogenesis and clinical outcome.

  7. The Clinically-tested S1P Receptor Agonists, FTY720 and BAF312, Demonstrate Subtype-Specific Bradycardia (S1P1) and Hypertension (S1P3) in Rat

    PubMed Central

    Fryer, Ryan M.; Muthukumarana, Akalushi; Harrison, Paul C.; Nodop Mazurek, Suzanne; Chen, Rong Rhonda; Harrington, Kyle E.; Dinallo, Roger M.; Horan, Joshua C.; Patnaude, Lori; Modis, Louise K.; Reinhart, Glenn A.

    2012-01-01

    Sphingosine-1-phospate (S1P) and S1P receptor agonists elicit mechanism-based effects on cardiovascular function in vivo. Indeed, FTY720 (non-selective S1PX receptor agonist) produces modest hypertension in patients (2–3 mmHg in 1-yr trial) as well as acute bradycardia independent of changes in blood pressure. However, the precise receptor subtypes responsible is controversial, likely dependent upon the cardiovascular response in question (e.g. bradycardia, hypertension), and perhaps even species-dependent since functional differences in rodent, rabbit, and human have been suggested. Thus, we characterized the S1P receptor subtype specificity for each compound in vitro and, in vivo, the cardiovascular effects of FTY720 and the more selective S1P1,5 agonist, BAF312, were tested during acute i.v. infusion in anesthetized rats and after oral administration for 10 days in telemetry-instrumented conscious rats. Acute i.v. infusion of FTY720 (0.1, 0.3, 1.0 mg/kg/20 min) or BAF312 (0.5, 1.5, 5.0 mg/kg/20 min) elicited acute bradycardia in anesthetized rats demonstrating an S1P1 mediated mechanism-of-action. However, while FTY720 (0.5, 1.5, 5.0 mg/kg/d) elicited dose-dependent hypertension after multiple days of oral administration in rat at clinically relevant plasma concentrations (24-hr mean blood pressure = 8.4, 12.8, 16.2 mmHg above baseline vs. 3 mmHg in vehicle controls), BAF312 (0.3, 3.0, 30.0 mg/kg/d) had no significant effect on blood pressure at any dose tested suggesting that hypertension produced by FTY720 is mediated S1P3 receptors. In summary, in vitro selectivity results in combination with studies performed in anesthetized and conscious rats administered two clinically tested S1P agonists, FTY720 or BAF312, suggest that S1P1 receptors mediate bradycardia while hypertension is mediated by S1P3 receptor activation. PMID:23285242

  8. High expression of sphingosine kinase 1 and S1P receptors in chemotherapy-resistant prostate cancer PC3 cells and their camptothecin-induced up-regulation

    SciTech Connect

    Akao, Yukihiro . E-mail: yakao@giib.or.jp; Banno, Yoshiko; Nakagawa, Yoshihito; Hasegawa, Nobuko; Kim, Tack-Joong; Murate, Takashi; Igarashi, Yasuyuki; Nozawa, Yoshinori

    2006-04-21

    Although most of pharmacological therapies for cancer utilize the apoptotic machinery of the cells, the available anti-cancer drugs are limited due to the ability of prostate cancer cells to escape from the anti-cancer drug-induced apoptosis. A human prostate cancer cell line PC3 is resistant to camptothecin (CPT). To elucidate the mechanism of this resistance, we have examined the involvement of sphingosine kinase (SPHK) and sphingosine 1-phosphate (S1P) receptor in CPT-resistant PC3 and -sensitive LNCaP cells. PC3 cells exhibited higher activity accompanied with higher expression levels of protein and mRNA of SPHK1, and also elevated expression of S1P receptors, S1P{sub 1} and S1P{sub 3}, as compared with those of LNCaP cells. The knockdown of SPHK1 by small interfering RNA and inhibition of S1P receptor signaling by pertussis toxin in PC3 cells induced significant inhibition of cell growth, suggesting implication of SPHK1 and S1P receptors in cell proliferation in PC3 cells. Furthermore, the treatment of PC3 cells with CPT was found to induce up-regulation of the SPHK1/S1P signaling by induction of both SPHK1 enzyme and S1P{sub 1}/S1P{sub 3} receptors. These findings strongly suggest that high expression and up-regulation of SPHK1 and S1P receptors protect PC3 cells from the apoptosis induced by CPT.

  9. Heterologous desensitization of the sphingosine-1-phosphate receptors by purinoceptor activation in renal mesangial cells

    PubMed Central

    Xin, Cuiyan; Ren, Shuyu; Pfeilschifter, Josef; Huwiler, Andrea

    2004-01-01

    Sphingosine-1-phosphate (S1P) is considered a potent mitogen for mesangial cells and activates the classical mitogen-activated protein kinase (MAPK) cascade via S1P receptors. In this study, we show that S1P signalling is rapidly desensitized upon S1P receptor activation. A complete loss of S1P sensitivity occurs after 10 min of S1P pretreatment and remains for at least 8 h. A similar desensitization is also seen with the S1P mimetic FTY720-phosphate, but not with the nonphosphorylated FTY720, nor with sphingosine or ceramide. Prestimulating the cells with extracellular ATP or UTP, which bind to and activate P2Y receptors on mesangial cells, a similar rapid desensitization of the S1P receptor occurs, suggesting a heterologous desensitization of S1P receptors by P2Y receptor activation. Furthermore, adenosine binding to P1 receptors triggers a similar desensitization. In contrast, two other growth factors, PDGF-BB and TGFβ2, have no significant effect on S1P-induced MAPK activation. S1P also triggers increased inositol trisphosphate (IP3) formation, which is completely abolished by S1P pretreatment but only partially by ATP pretreatment, suggesting that IP3 formation and MAPK activation stimulated by S1P involve different receptor subtypes. Increasing intracellular cAMP levels by forskolin pretreatment has a similar effect on desensitization as adenosine. Moreover, a selective A3 adenosine receptor agonist, which couples to phospholipase C and increases IP3 formation, exerted a similar effect. Pretreatment of cells with various protein kinase C (PKC) inhibitors prior to ATP prestimulation and subsequent S1P stimulation leads to a differential reversal of the ATP effect. Whereas the broad-spectrum protein kinase inhibitor staurosporine potently reverses the effect, the PKC-α inhibitor CGP41251, the PKC-δ inhibitor rottlerin and calphostin C show only a partial reversal at maximal concentrations. Suramin, which is reported as a selective S1P3 receptor antagonist

  10. Prolonging Survival of Corneal Transplantation by Selective Sphingosine-1-Phosphate Receptor 1 Agonist

    PubMed Central

    Gao, Min; Liu, Yong; Xiao, Yang; Han, Gencheng; Jia, Liang; Wang, Liqiang; Lei, Tian; Huang, Yifei

    2014-01-01

    Corneal transplantation is the most used therapy for eye disorders. Although the cornea is somewhat an immune privileged organ, immune rejection is still the major problem that reduces the success rate. Therefore, effective chemical drugs that regulate immunoreactions are needed to improve the outcome of corneal transplantations. Here, a sphingosine-1-phosphate receptor 1 (S1P1) selective agonist was systematically evaluated in mouse allogeneic corneal transplantation and compared with the commonly used immunosuppressive agents. Compared with CsA and the non-selective sphingosine 1-phosphate (S1P) receptor agonist FTY720, the S1P1 selective agonist can prolong the survival corneal transplantation for more than 30 days with a low immune response. More importantly, the optimal dose of the S1P1 selective agonist was much less than non-selective S1P receptor agonist FTY720, which would reduce the dose-dependent toxicity in drug application. Then we analyzed the mechanisms of the selected S1P1 selective agonist on the immunosuppression. The results shown that the S1P1 selective agonist could regulate the distribution of the immune cells with less CD4+ T cells and enhanced Treg cells in the allograft, moreover the expression of anti-inflammatory cytokines TGF-β1 and IL-10 unregulated which can reduce the immunoreactions. These findings suggest that S1P1 selective agonist may be a more appropriate immunosuppressive compound to effectively prolong mouse allogeneic corneal grafts survival. PMID:25216235

  11. Novel S1P(1) receptor agonists--part 3: from thiophenes to pyridines.

    PubMed

    Bolli, Martin H; Abele, Stefan; Birker, Magdalena; Bravo, Roberto; Bur, Daniel; de Kanter, Ruben; Kohl, Christopher; Grimont, Julien; Hess, Patrick; Lescop, Cyrille; Mathys, Boris; Müller, Claus; Nayler, Oliver; Rey, Markus; Scherz, Michael; Schmidt, Gunther; Seifert, Jürgen; Steiner, Beat; Velker, Jörg; Weller, Thomas

    2014-01-01

    In preceding communications we summarized our medicinal chemistry efforts leading to the identification of potent, selective, and orally active S1P1 agonists such as the thiophene derivative 1. As a continuation of these efforts, we replaced the thiophene in 1 by a 2-, 3-, or 4-pyridine and obtained less lipophilic, potent, and selective S1P1 agonists (e.g., 2) efficiently reducing blood lymphocyte count in the rat. Structural features influencing the compounds' receptor affinity profile and pharmacokinetics are discussed. In addition, the ability to penetrate brain tissue has been studied for several compounds. As a typical example for these pyridine based S1P1 agonists, compound 53 showed EC50 values of 0.6 and 352 nM for the S1P1 and S1P3 receptor, respectively, displayed favorable PK properties, and penetrated well into brain tissue. In the rat, compound 53 maximally reduced the blood lymphocyte count for at least 24 h after oral dosing of 3 mg/kg. PMID:24367923

  12. Evaluation of commercial antibodies against human sphingosine-1-phosphate receptor 1.

    PubMed

    Talmont, Franck; Moulédous, Lionel

    2014-05-01

    Sphingosine-1-phosphate receptor 1 (S1P1), also called endothelial differentiation gene 1, plays an important role in migration, proliferation, and survival of several types of cells including endothelial cells and lymphocytes and is involved in multiple sclerosis. Two commercial rabbit anti-S1P1 antibodies (polyclonal and monoclonal) were tested on CHO cells expressing S1P1 receptors fused to the green fluorescent protein at the C-terminal end and on Pichia pastoris and HEK cells expressing cmyc-tagged S1P1. Polyclonal antibodies did not give any signal by Western blot, immunofluorescence, and flow cytofluorometry. Monoclonal antibodies were able to reveal an unspecific band by Western blot performed on various cell types. Consequently, in our hands and using our protocols, we show that these antibodies did not specifically detect S1P1 receptors.

  13. S1P1 Receptor Modulation with Cyclical Recovery from Lymphopenia Ameliorates Mouse Model of Multiple Sclerosis

    PubMed Central

    Gonzalez-Cabrera, Pedro J.; Cahalan, Stuart M.; Nguyen, Nhan; Sarkisyan, Gor; Leaf, Nora B.; Cameron, Michael D.; Kago, Tomoyuki

    2012-01-01

    Multiple sclerosis (MS) therapies modulate T-cell autoimmunity in the central nervous system (CNS) but may exacerbate latent infections. Fingolimod, a nonselective sphingosine-1-phosphate (S1P) receptor agonist that induces sustained lymphopenia and accumulates in the CNS, represents a new treatment modality for MS. We hypothesized that sustained lymphopenia would not be required for efficacy and that a selective, CNS-penetrant, peripherally short-acting, S1P1 agonist would show full efficacy in a mouse MS model. Using daily treatment with 10 mg/kg 2-(4-(5-(3,4-diethoxyphenyl)-1,2,4-oxadiazol-3-yl)-2,3-dihydro-1H-inden-1-yl amino)ethanol (CYM-5442) at the onset of clinical signs in myelin oligodendrocyte glycoprotein MOG35–55- induced experimental allergic encephalomyelitis (EAE), we assessed clinical scores, CNS cellular infiltration, demyelination, and gliosis for 12 days with CYM-5442, vehicle, or fingolimod. CYM-5442 levels in CNS and plasma were determined at experiment termination, and blood lymphopenia was measured 3 and 24 h after the last injection. Plasma levels of cytokines were assayed at the end of the protocol. Changes in S1P1-enhanced green fluorescent protein expression on neurons and astrocytes during active EAE and upon CYM-5442 treatment were quantified with flow cytometry and Western blotting by using native-locus enhanced green fluorescent protein-tagged S1P1 mice. S1P1 agonism alone reduced pathological features as did fingolimod (maximally lymphopenic throughout), despite full reversal of lymphopenia within each dosing interval. CYM-5442 levels in CNS but not in plasma were sustained. Neuronal and astrocytic S1P1 expression in EAE was suppressed by CYM-5442 treatment, relative to vehicle, and levels of key cytokines, such as interleukin 17A, were also significantly reduced in drug-treated mice. S1P1-selective agonists that induce reversible lymphopenia while persisting in the CNS may be effective MS treatments. PMID:22031473

  14. Sphingosine 1-phosphate signalling through the G-protein-coupled receptor Edg-1.

    PubMed Central

    Zondag, G C; Postma, F R; Etten, I V; Verlaan, I; Moolenaar, W H

    1998-01-01

    Sphingosine 1-phosphate (S1P) and lysophosphatidic acid (LPA) are structurally related lipid mediators that act on distinct G-protein-coupled receptors to evoke similar responses, including Ca2+ mobilization, adenylate cyclase inhibition, and mitogen-activated protein (MAP) kinase activation. However, little is still known about the respective receptors. A recently cloned putative LPA receptor (Vzg-1/Edg-2) is similar to an orphan Gi-coupled receptor termed Edg-1. Here we show that expression of Edg-1 in Sf9 and COS-7 cells results in inhibition of adenylate cyclase and activation of MAP kinase (Gi-mediated), but not Ca2+ mobilization, in response to S1P. These responses are specific in that (i) S1P action is not mimicked by LPA, and (ii) Vzg-1/Edg-2 cannot substitute for Edg-1. Thus the Edg-1 receptor is capable of mediating a subset of the cellular responses to S1P. PMID:9480864

  15. Accurate quantification of sphingosine-1-phosphate in normal and Fabry disease plasma, cells and tissues by LC-MS/MS with (13)C-encoded natural S1P as internal standard.

    PubMed

    Mirzaian, Mina; Wisse, Patrick; Ferraz, Maria J; Marques, André R A; Gabriel, Tanit L; van Roomen, Cindy P A A; Ottenhoff, Roelof; van Eijk, Marco; Codée, Jeroen D C; van der Marel, Gijsbert A; Overkleeft, Herman S; Aerts, Johannes M

    2016-08-01

    We developed a mass spectrometric procedure to quantify sphingosine-1-phosphate (S1P) in biological materials. The use of newly synthesized (13)C5 C18-S1P and commercial C17-S1P as internal standards rendered very similar results with respect to linearity, limit of detection and limit of quantitation. Caution is warranted with determination of plasma S1P levels. Earlier it was reported that S1P is elevated in plasma of Fabry disease patients. We investigated this with the improved quantification. No clear conclusion could be drawn for patient plasma samples given the lack of uniformity of blood collection and plasma preparation. To still obtain insight, plasma and tissues were identically collected from α-galactosidase A deficient Fabry mice and matched control animals. No significant difference was observed in plasma S1P levels. A significant 2.3 fold increase was observed in kidney of Fabry mice, but not in liver and heart. Comparative analysis of S1P in cultured fibroblasts from normal subjects and classically affected Fabry disease males revealed no significant difference. In conclusion, accurate quantification of S1P in biological materials is feasible by mass spectrometry using the internal standards (13)C5 C18-S1P or C17-S1P. Significant local increases of S1P in the kidney might occur in Fabry disease as suggested by the mouse model. PMID:27221202

  16. Synthesis and Biological Evaluation of Sphingosine Kinase Substrates as Sphingosine-1-Phosphate Receptor Prodrugs

    PubMed Central

    Foss, Frank W.; Mathews, Thomas P.; Kharel, Yugesh; Kennedy, Perry C.; Snyder, Ashley H.; Davis, Michael D.; Lynch, Kevin R.; Macdonald, Timothy L.

    2009-01-01

    In the search for bioactive sphingosine 1-phosphate (S1P) receptor ligands, a series of 2-amino-2-heterocyclic-propanols were synthesized. These molecules were discovered to be substrates of human-sphingosine kinases 1 and 2 (SPHK1 and SPHK2). When phosphorylated, the resultant phosphates showed varied activities at the five sphingosine-1-phosphate (S1P) receptors (S1P1–5). Agonism at S1P1 was displayed in vivo by induction of lymphopenia. A stereochemical preference of the quaternary carbon was crucial for phosphorylation by the kinases and alters binding affinities at the S1P receptors. Oxazole and oxadiazole compounds are superior kinase substrates to FTY720, the prototypical prodrug immunomodulator, fingolimod (FTY720). The oxazole-derived structure was the most active for human SPHK2. Imidazole analogues were less active substrates for SPHKs, but more potent and selective agonists of the S1P1 receptor; additionally, the imidazole class of compounds rendered mice lymphopenic. PMID:19632123

  17. Sphingosine-1-Phosphate Elicits Receptor-Dependent Calcium Signaling in Retinal Amacrine Cells

    PubMed Central

    Crousillac, Scott; Colonna, Jeremy; McMains, Emily; Dewey, Jill Sayes

    2009-01-01

    Evidence is emerging indicating that sphingosine-1-phosphate (S1P) participates in signaling in the retina. To determine whether S1P might be involved in signaling in the inner retina specifically, we examine the effects of this sphingolipid on cultured retinal amacrine cells. Whole cell voltage-clamp recordings reveal that S1P activates a cation current that is dependent on signaling through Gi and phospholipase C. These observations are consistent with the involvement of members of the S1P receptor family of G-protein-coupled receptors in the production of the current. Immunocytochemistry and PCR amplification provide evidence for the expression of S1P1R and S1P3R in amacrine cells. The receptor-mediated channel activity is shown to be highly sensitive to blockade by lanthanides consistent with the behavior of transient receptor potential canonical (TRPC) channels. PCR products amplified from amacrine cells reveal that TRPCs 1 and 3–7 channel subunits have the potential to be expressed. Because TRPC channels provide a Ca2+ entry pathway, we asked whether S1P caused cytosolic Ca2+ elevations in amacrine cells. We show that S1P-dependent Ca2+ elevations do occur in these cells and that they might be mediated by S1P1R and S1P3R. The Ca2+ elevations are partially due to release from internal stores, but the largest contribution is from influx across the plasma membrane. The effect of inhibition of sphingosine kinase suggests that the production of cytosolic S1P underlies the sustained nature of the Ca2+ elevations. Elucidation of the downstream effects of these signals will provide clues to the role of S1P in regulating inner retinal function. PMID:19776367

  18. Ponesimod, a selective S1P1 receptor modulator: a potential treatment for multiple sclerosis and other immune-mediated diseases

    PubMed Central

    D’Ambrosio, Daniele; Freedman, Mark S.; Prinz, Joerg

    2016-01-01

    The first oral treatment for relapsing multiple sclerosis, the nonselective sphingosine-1-phosphate receptor (S1PR) modulator fingolimod, led to identification of a pivotal role of sphingosine-1-phosphate and one of its five known receptors, S1P1R, in regulation of lymphocyte trafficking in multiple sclerosis. Modulation of S1P3R, initially thought to cause some of fingolimod’s side effects, prompted the search for novel compounds with high selectivity for S1P1R. Ponesimod is an orally active, selective S1P1R modulator that causes dose-dependent sequestration of lymphocytes in lymphoid organs. In contrast to the long half-life/slow elimination of fingolimod, ponesimod is eliminated within 1 week of discontinuation and its pharmacological effects are rapidly reversible. Clinical data in multiple sclerosis have shown a dose-dependent therapeutic effect of ponesimod and defined 20 mg as a daily dose with desired efficacy, and acceptable safety and tolerability. Phase II clinical data have also shown therapeutic efficacy of ponesimod in psoriasis. These findings have increased our understanding of psoriasis pathogenesis and suggest clinical utility of S1P1R modulation for treatment of various immune-mediated disorders. A gradual dose titration regimen was found to minimize the cardiac effects associated with initiation of ponesimod treatment. Selectivity for S1P1R, rapid onset and reversibility of pharmacological effects, and an optimized titration regimen differentiate ponesimod from fingolimod, and may lead to better safety and tolerability. Ponesimod is currently in phase III clinical development to assess efficacy and safety in relapsing multiple sclerosis. A phase II study is also ongoing to investigate the potential utility of ponesimod in chronic graft versus host disease. PMID:26770667

  19. Sphingosine 1-phosphate receptor activation enhances BMP-2-induced osteoblast differentiation

    SciTech Connect

    Sato, Chieri; Iwasaki, Tsuyoshi; Kitano, Sachie; Tsunemi, Sachi; Sano, Hajime

    2012-06-22

    Highlights: Black-Right-Pointing-Pointer We investigated the role of S1P signaling for osteoblast differentiation. Black-Right-Pointing-Pointer Both S1P and FTY enhanced BMP-2-stimulated osteoblast differentiation by C2C12 cells. Black-Right-Pointing-Pointer S1P signaling enhanced BMP-2-stimulated Smad and ERK phosphorylation by C2C12 cells. Black-Right-Pointing-Pointer MEK/ERK signaling is a pathway underlying S1P signaling for osteoblast differentiation. -- Abstract: We previously demonstrated that sphingosine 1-phosphate (S1P) receptor-mediated signaling induced proliferation and prostaglandin productions by synovial cells from rheumatoid arthritis (RA) patients. In the present study we investigated the role of S1P receptor-mediated signaling for osteoblast differentiation. We investigated osteoblast differentiation using C2C12 myoblasts, a cell line derived from murine satellite cells. Osteoblast differentiation was induced by the treatment of bone morphogenic protein (BMP)-2 in the presence or absence of either S1P or FTY720 (FTY), a high-affinity agonist of S1P receptors. Osteoblast differentiation was determined by osteoblast-specific transcription factor, Runx2 mRNA expression, alkaline phosphatase (ALP) activity and osteocalcin production by the cells. Smad1/5/8 and extracellular signal-regulated kinase (ERK) 1/2 phosphorylation was examined by Western blotting. Osteocalcin production by C2C12 cells were determined by ELISA. Runx2 expression and ALP activity by BMP-2-stimulated C2C12 cells were enhanced by addition of either S1P or FTY. Both S1P and FTY enhanced BMP-2-induced ERK1/2 and Smad1/5/8 phosphorylation. The effect of FTY was stronger than that of S1P. S1P receptor-mediated signaling on osteoblast differentiation was inhibited by addition of mitogen-activated protein kinase/ERK kinase (MEK) 1/2 inhibitor, indicating that the S1P receptor-mediated MEK1/2-ERK1/2 signaling pathway enhanced BMP-2-Smad signaling. These results indicate that S1P

  20. Hematopoietic Sphingosine 1-Phosphate Lyase Deficiency Decreases Atherosclerotic Lesion Development in LDL-Receptor Deficient Mice

    PubMed Central

    Bot, Martine; Van Veldhoven, Paul P.; de Jager, Saskia C. A.; Johnson, Jason; Nijstad, Niels; Van Santbrink, Peter J.; Westra, Marijke M.; Van Der Hoeven, Gerd; Gijbels, Marion J.; Müller-Tidow, Carsten; Varga, Georg; Tietge, Uwe J. F.; Kuiper, Johan; Van Berkel, Theo J. C.; Nofer, Jerzy-Roch

    2013-01-01

    Aims Altered sphingosine 1-phosphate (S1P) homeostasis and signaling is implicated in various inflammatory diseases including atherosclerosis. As S1P levels are tightly controlled by S1P lyase, we investigated the impact of hematopoietic S1P lyase (Sgpl1−/−) deficiency on leukocyte subsets relevant to atherosclerosis. Methods and Results LDL receptor deficient mice that were transplanted with Sgpl1−/− bone marrow showed disrupted S1P gradients translating into lymphopenia and abrogated lymphocyte mitogenic and cytokine response as compared to controls. Remarkably however, Sgpl1−/− chimeras displayed mild monocytosis, due to impeded stromal retention and myelopoiesis, and plasma cytokine and macrophage expression patterns, that were largely compatible with classical macrophage activation. Collectively these two phenotypic features of Sgpl1 deficiency culminated in diminished atherogenic response. Conclusions Here we not only firmly establish the critical role of hematopoietic S1P lyase in controlling S1P levels and T cell trafficking in blood and lymphoid tissue, but also identify leukocyte Sgpl1 as critical factor in monocyte macrophage differentiation and function. Its, partly counterbalancing, pro- and anti-inflammatory activity spectrum imply that intervention in S1P lyase function in inflammatory disorders such as atherosclerosis should be considered with caution. PMID:23700419

  1. Sphingosine 1-phosphate receptors are essential mediators of eyelid closure during embryonic development.

    PubMed

    Herr, Deron R; Lee, Chang-Wook; Wang, Wei; Ware, Adam; Rivera, Richard; Chun, Jerold

    2013-10-11

    The fetal development of the mammalian eyelid involves the expansion of the epithelium over the developing cornea, fusion into a continuous sheet covering the eye, and a splitting event several weeks later that results in the formation of the upper and lower eyelids. Recent studies have revealed a significant number of molecular signaling components that are essential mediators of eyelid development. Receptor-mediated sphingosine 1-phosphate (S1P) signaling is known to influence diverse biological processes, but its involvement in eyelid development has not been reported. Here, we show that two S1P receptors, S1P2 and S1P3, are collectively essential mediators of eyelid closure during murine development. Homozygous deletion of the gene encoding either receptor has no apparent effect on eyelid development, but double-null embryos are born with an "eyes open at birth" defect due to a delay in epithelial sheet extension. Both receptors are expressed in the advancing epithelial sheet during the critical period of extension. Fibroblasts derived from double-null embryos have a deficient response to epidermal growth factor, suggesting that S1P2 and S1P3 modulate this essential signaling pathway during eyelid closure.

  2. Sphingosine-1-phosphate receptor 1 transmits estrogens' effects in endothelial cells.

    PubMed

    Sukocheva, Olga; Wadham, Carol; Gamble, Jennifer; Xia, Pu

    2015-12-01

    We have previously reported that the steroid hormone estrogens stimulate activation of sphingosine kinase 1 (SphK1) and sphingosine-1-phosphate (S1P) receptors in breast cancer cells. Both estrogens and S1P are potent biological modulators of endothelial function in vasculature able to activate multiple effectors, including endothelial nitric oxide synthase (eNOS). In this study we report that treatment of endothelial cells (ECs) with 17β-estradiol (E2) resulted in a rapid, transient, and dose-dependent increase in SphK activity and increased S1P production. The effect was not reproduced by the inactive E2 analogue 17α-E2. Expression of the dominant-negative mutant SphK1(G82D) or transfection of SphK1-targeted siRNA in ECs caused not only a defect in SphK activation by E2, but also a significant inhibition of E2-induced activation of Akt/eNOS. Furthermore, E2 treatment induced internalization of plasma membrane S1P1 receptor, accompanied with an increase in the amount of cytosolic S1P1. By down-regulating S1P1 receptor expression, the S1P1-specific antisense oligonucleotides significantly inhibited E2-induced activation of Akt/eNOS in ECs. E2-induced EC migration and tube formation were also inhibited by S1P1 down-regulation. Thus, the findings indicate an important role of the SphK1/S1P1 pathway in mediating estrogen signaling and its actions in vasculature.

  3. Distinct generation, pharmacology, and distribution of sphingosine 1-phosphate and dihydro-sphingosine 1-phosphate in human neural progenitor cells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In-vivo and in-vitro studies suggest a crucial role for Sphingosine 1-phosphate (S1P) and its receptors in the development of the nervous system. Dihydrosphingosine 1-phosphate (dhS1P), a reduced form of S1P, is an active ligand at S1P receptors, but the pharmacology and physiology of dhS1P has not...

  4. Synthesis and evaluation of fluorinated fingolimod (FTY720) analogues for sphingosine-1-phosphate receptor molecular imaging by positron emission tomography.

    PubMed

    Shaikh, Rizwan S; Schilson, Stefanie S; Wagner, Stefan; Hermann, Sven; Keul, Petra; Levkau, Bodo; Schäfers, Michael; Haufe, Günter

    2015-04-23

    Sphingosine-1-phosphate (S1P) is a lysophospholipid that evokes a variety of biological responses via stimulation of a set of cognate G-protein coupled receptors (GPCRs): S1P1-S1P5. S1P and its receptors (S1PRs) play important roles in the immune, cardiovascular, and central nervous systems and have also been implicated in carcinogenesis. Recently, the S1P analogue Fingolimod (FTY720) has been approved for the treatment of patients with relapsing multiple sclerosis. This work presents the synthesis of various fluorinated structural analogues of FTY720, their in vitro and in vivo biological testing, and their development and application as [(18)F]radiotracers for the study of S1PR biodistribution and imaging in mice using small-animal positron emission tomography (PET).

  5. Synthesis and evaluation of fluorinated fingolimod (FTY720) analogues for sphingosine-1-phosphate receptor molecular imaging by positron emission tomography.

    PubMed

    Shaikh, Rizwan S; Schilson, Stefanie S; Wagner, Stefan; Hermann, Sven; Keul, Petra; Levkau, Bodo; Schäfers, Michael; Haufe, Günter

    2015-04-23

    Sphingosine-1-phosphate (S1P) is a lysophospholipid that evokes a variety of biological responses via stimulation of a set of cognate G-protein coupled receptors (GPCRs): S1P1-S1P5. S1P and its receptors (S1PRs) play important roles in the immune, cardiovascular, and central nervous systems and have also been implicated in carcinogenesis. Recently, the S1P analogue Fingolimod (FTY720) has been approved for the treatment of patients with relapsing multiple sclerosis. This work presents the synthesis of various fluorinated structural analogues of FTY720, their in vitro and in vivo biological testing, and their development and application as [(18)F]radiotracers for the study of S1PR biodistribution and imaging in mice using small-animal positron emission tomography (PET). PMID:25826109

  6. Endocytosis of Ligand-Activated Sphingosine 1-Phosphate Receptor 1 Mediated by the Clathrin-Pathway.

    PubMed

    Reeves, Patrick M; Kang, Yuan-Lin; Kirchhausen, Tom

    2016-01-01

    The sphingosine 1-phosphate receptor 1 (S1PR1) is one of five G protein-coupled receptors activated by the lipid sphingosine 1-phosphate (S1P). Stimulation of S1PR1 by binding S1P or the synthetic agonist FTY720P results in rapid desensitization, associated in part with depletion of receptor from the cell surface. We report here combining spinning disc confocal fluorescence microscopy and flow cytometry to show that rapid internalization of activated S1PR1 relies on a functional clathrin-mediated endocytic pathway. Uptake of activated S1PR1 was strongly inhibited in cells disrupted in their clathrin-mediated endocytosis by depleting clathrin or AP-2 or by treating cells with dynasore-OH. The uptake of activated S1P1R was strongly inhibited in cells lacking both β-arrestin 1 and β-arrestin 2, indicating that activated S1PR1 follows the canonical route of endocytosis for G-protein coupled receptor's (GPCR)'s.

  7. Identification of the orphan GPCR, P2Y(10) receptor as the sphingosine-1-phosphate and lysophosphatidic acid receptor.

    PubMed

    Murakami, Masanori; Shiraishi, Akira; Tabata, Kenichi; Fujita, Norihisa

    2008-07-11

    Phylogenetic analysis of transmembrane regions of GPCRs using PHYLIP indicated that the orphan receptor P2Y(10) receptor was classified into the cluster consisting nucleotide and lipid receptors. Based on the results, we studied the abilities of nucleotides and lipids to activate the P2Y(10) receptors. As a result, sphingosine-1-phosphate (S1P) and lysophosphatidic acid (LPA) evoked intracellular Ca(2+) increases in the CHO cells stably expressing the P2Y(10) fused with a G(16alpha) protein. These Ca(2+) responses were inhibited by S1P receptor and LPA receptor antagonists. The introduction of siRNA designed for P2Y(10) receptor into the P2Y(10)-CHO cells effectively blocked both S1P- and LPA-induced Ca(2+) increases. RT-PCR analysis showed that the mouse P2Y(10) was expressed in reproductive organs, brain, lung and skeletal muscle, suggesting the receptor plays physiological roles throughout the whole body. In conclusion, the P2Y(10) receptor is the first receptor identified as a dual lysophospholipid receptor. PMID:18466763

  8. Characterization of a novel sphingosine 1-phosphate receptor, Edg-8.

    PubMed

    Im, D S; Heise, C E; Ancellin, N; O'Dowd, B F; Shei, G J; Heavens, R P; Rigby, M R; Hla, T; Mandala, S; McAllister, G; George, S R; Lynch, K R

    2000-05-12

    Three G protein-coupled receptors (Edg-1, Edg-3, and Edg-5) for the lysolipid phosphoric acid mediator sphingosine 1-phosphate have been described by molecular cloning. Using a similar sequence that we found in the expressed sequence tag data base, we cloned and characterized of a fourth, high affinity, rat brain sphingosine 1-phosphate receptor, Edg-8. When HEK293T cells were co-transfected with Edg-8 and G protein DNAs, prepared membranes showed sphingosine 1- phosphate-dependent increases in [(35)S]guanosine 5'-(3-O-thio)triphosphate binding with an EC(50) of 90 nm. In a rat hepatoma Rh7777 cell line that exhibits modest endogenous responses to sphingosine 1-phosphate, this lipid mediator inhibited forskolin-driven rises in cAMP by greater than 90% when the cells were transfected with Edg-8 DNA (IC(50) 0.7 nm). This response is blocked fully by prior treatment of cultures with pertussis toxin, thus implicating signaling through G(i/o)alpha proteins. Furthermore, Xenopus oocytes exhibit a calcium response to sphingosine 1-phosphate after injection of Edg-8 mRNA, but only when oocytes are co-injected with chimeric G(q/i)alpha protein mRNA. Membranes from HEK293T and Rh7777 cell cultures expressing Edg-8 exhibited high affinity (K(D) = 2 nm) binding for radiolabeled sphingosine 1-phosphate. Rat Edg-8 RNA is expressed in spleen and throughout adult rat brain where in situ hybridization revealed it to be associated with white matter. Together our data demonstrate that Edg-8 is a high affinity sphingosine 1-phosphate receptor that couples to G(i/o)alpha proteins and is expressed predominantly by oligodendrocytes and/or fibrous astrocytes in the rat brain.

  9. Sphingosine 1-phosphate is a ligand for peroxisome proliferator-activated receptor-γ that regulates neoangiogenesis.

    PubMed

    Parham, Kate A; Zebol, Julia R; Tooley, Katie L; Sun, Wai Y; Moldenhauer, Lachlan M; Cockshell, Michaelia P; Gliddon, Briony L; Moretti, Paul A; Tigyi, Gabor; Pitson, Stuart M; Bonder, Claudine S

    2015-09-01

    Sphingosine 1-phosphate (S1P) is a bioactive lipid that can function both extracellularly and intracellularly to mediate a variety of cellular processes. Using lipid affinity matrices and a radiolabeled lipid binding assay, we reveal that S1P directly interacts with the transcription factor peroxisome proliferator-activated receptor (PPAR)γ. Herein, we show that S1P treatment of human endothelial cells (ECs) activated a luciferase-tagged PPARγ-specific gene reporter by ∼12-fold, independent of the S1P receptors. More specifically, in silico docking, gene reporter, and binding assays revealed that His323 of the PPARγ ligand binding domain is important for binding to S1P. PPARγ functions when associated with coregulatory proteins, and herein we identify that peroxisome proliferator-activated receptor-γ coactivator 1 (PGC1)β binds to PPARγ in ECs and their progenitors (nonadherent endothelial forming cells) and that the formation of this PPARγ:PGC1β complex is increased in response to S1P. ECs treated with S1P selectively regulated known PPARγ target genes with PGC1β and plasminogen-activated inhibitor-1 being increased, no change to adipocyte fatty acid binding protein 2 and suppression of CD36. S1P-induced in vitro tube formation was significantly attenuated in the presence of the PPARγ antagonist GW9662, and in vivo application of GW9662 also reduced vascular development in Matrigel plugs. Interestingly, activation of PPARγ by the synthetic ligand troglitazone also reduced tube formation in vitro and in vivo. To support this, Sphk1(-/-)Sphk2(+/-) mice, with low circulating S1P levels, demonstrated a similar reduction in vascular development. Taken together, our data reveal that the transcription factor, PPARγ, is a bona fide intracellular target for S1P and thus suggest that the S1P:PPARγ:PGC1β complex may be a useful target to manipulate neovascularization.

  10. ETS-1-mediated transcriptional up-regulation of CD44 is required for sphingosine-1-phosphate receptor subtype 3-stimulated chemotaxis.

    PubMed

    Zhang, Wenliang; Zhao, Jiawei; Lee, Jen-Fu; Gartung, Allison; Jawadi, Hiba; Lambiv, Wanyu Louis; Honn, Kenneth V; Lee, Menq-Jer

    2013-11-01

    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.

  11. Berberine attenuates high glucose-induced fibrosis by activating the G protein-coupled bile acid receptor TGR5 and repressing the S1P2/MAPK signaling pathway in glomerular mesangial cells.

    PubMed

    Yang, Zhiying; Li, Jie; Xiong, Fengxiao; Huang, Junying; Chen, Cheng; Liu, Peiqing; Huang, Heqing

    2016-08-15

    Berberine (BBR) exerts powerful renoprotective effects on diabetic nephropathy (DN), but the underlying mechanisms remain unclear. We previously demonstrated that activation of the G protein-coupled bile acid receptor TGR5 ameliorates diabetic nephropathy by inhibiting the activation of the sphingosine 1-phosphate (S1P)/sphingosine 1-phosphate receptor 2 (S1P2) signaling pathway. In this study, we explored the role of TGR5 in the BBR-induced downregulation of sphingosine 1-phosphate receptor 2 (S1P2)/mitogen-activated protein kinase (MAPK)-mediated fibrosis in glomerular mesangial cells (GMCs). Results showed that, BBR suppressed the expression of FN, ICAM-1, and TGF-β1 in high-glucose cultures of GMCs, and the phosphorylation level of c-Jun/c-Fos was downregulated. The high glucose lowered TGR5 expression in a time-dependent manner; this effect was reversed by BBR in a dose-dependent manner. The TGR5 agonist INT-777 decreased the high glucose-induced FN, ICAM-1, and TGF-β1 protein contents. In addition, TGR5 siRNA blocked S1P2 degradation by BBR. And MAPK signaling, which plays important regulatory roles in the pathological progression of DN, was activated by TGR5 siRNA. Apart from this, MAPK signaling as well as FN, ICAM-1, and TGF-β1 suppressed by BBR under high glucose conditions were limited by TGR5 depletion. Thus, BBR decreases FN, ICAM-1, and TGF-β1 levels under high glucose conditions in GMCs possibly by activating TGR5 and inhibiting S1P2/MAPK signaling. PMID:27292312

  12. Sphingosine-1-phosphate receptor 1 agonism attenuates lung ischemia-reperfusion injury

    PubMed Central

    Stone, Matthew L.; Sharma, Ashish K.; Zhao, Yunge; Charles, Eric J.; Huerter, Mary E.; Johnston, William F.; Kron, Irving L.; Lynch, Kevin R.

    2015-01-01

    Outcomes for lung transplantation are the worst of any solid organ, and ischemia-reperfusion injury (IRI) limits both short- and long-term outcomes. Presently no therapeutic agents are available to prevent IRI. Sphingosine 1-phosphate (S1P) modulates immune function through binding to a set of G protein-coupled receptors (S1PR1-5). Although S1P has been shown to attenuate lung IRI, the S1P receptors responsible for protection have not been defined. The present study tests the hypothesis that protection from lung IRI is primarily mediated through S1PR1 activation. Mice were treated with either vehicle, FTY720 (a nonselective S1P receptor agonist), or VPC01091 (a selective S1PR1 agonist and S1PR3 antagonist) before left lung IR. Function, vascular permeability, cytokine expression, neutrophil infiltration, and myeloperoxidase levels were measured in lungs. After IR, both FTY720 and VPC01091 significantly improved lung function (reduced pulmonary artery pressure and increased pulmonary compliance) vs. vehicle control. In addition, FTY720 and VPC01091 significantly reduced vascular permeability, expression of proinflammatory cytokines (IL-6, IL-17, IL-12/IL-23 p40, CC chemokine ligand-2, and TNF-α), myeloperoxidase levels, and neutrophil infiltration compared with control. No significant differences were observed between VPC01091 and FTY720 treatment groups. VPC01091 did not significantly affect elevated invariant natural killer T cell infiltration after IR, and administration of an S1PR1 antagonist reversed VPC01091-mediated protection after IR. In conclusion, VPC01091 and FTY720 provide comparable protection from lung injury and dysfunction after IR. These findings suggest that S1P-mediated protection from IRI is mediated by S1PR1 activation, independent of S1PR3, and that selective S1PR1 agonists may provide a novel therapeutic strategy to prevent lung IRI. PMID:25910934

  13. Sphingosine-1-phosphate receptor 1 agonism attenuates lung ischemia-reperfusion injury.

    PubMed

    Stone, Matthew L; Sharma, Ashish K; Zhao, Yunge; Charles, Eric J; Huerter, Mary E; Johnston, William F; Kron, Irving L; Lynch, Kevin R; Laubach, Victor E

    2015-06-15

    Outcomes for lung transplantation are the worst of any solid organ, and ischemia-reperfusion injury (IRI) limits both short- and long-term outcomes. Presently no therapeutic agents are available to prevent IRI. Sphingosine 1-phosphate (S1P) modulates immune function through binding to a set of G protein-coupled receptors (S1PR1-5). Although S1P has been shown to attenuate lung IRI, the S1P receptors responsible for protection have not been defined. The present study tests the hypothesis that protection from lung IRI is primarily mediated through S1PR1 activation. Mice were treated with either vehicle, FTY720 (a nonselective S1P receptor agonist), or VPC01091 (a selective S1PR1 agonist and S1PR3 antagonist) before left lung IR. Function, vascular permeability, cytokine expression, neutrophil infiltration, and myeloperoxidase levels were measured in lungs. After IR, both FTY720 and VPC01091 significantly improved lung function (reduced pulmonary artery pressure and increased pulmonary compliance) vs. vehicle control. In addition, FTY720 and VPC01091 significantly reduced vascular permeability, expression of proinflammatory cytokines (IL-6, IL-17, IL-12/IL-23 p40, CC chemokine ligand-2, and TNF-α), myeloperoxidase levels, and neutrophil infiltration compared with control. No significant differences were observed between VPC01091 and FTY720 treatment groups. VPC01091 did not significantly affect elevated invariant natural killer T cell infiltration after IR, and administration of an S1PR1 antagonist reversed VPC01091-mediated protection after IR. In conclusion, VPC01091 and FTY720 provide comparable protection from lung injury and dysfunction after IR. These findings suggest that S1P-mediated protection from IRI is mediated by S1PR1 activation, independent of S1PR3, and that selective S1PR1 agonists may provide a novel therapeutic strategy to prevent lung IRI. PMID:25910934

  14. Sphingosine-1-Phosphate Induces the Migration and Angiogenesis of Epcs Through the Akt Signaling Pathway via Sphingosine-1-Phosphate Receptor 3/Platelet-Derived Growth Factor Receptor-β.

    PubMed

    Wang, Hang; Cai, Ke-Yin; Li, Wei; Huang, Hao

    2015-12-01

    Endothelial progenitor cells (EPCs) play a fundamental role in neoangiogenesis and tumor angiogenesis. Through the sphingosine-1-phosphate receptor 3 (S1PR3), sphingosine-1-phosphate (S1P) can stimulate the functional capacity of EPCs. Platelet-derived growth factor receptor-beta (PDGFR-β) contributes to the migration and angiogenesis of EPCs. This study aimed to investigate whether S1P induces the migration and angiogenesis of EPCs through the S1PR3/PDGFR-β/Akt signaling pathway. We used the Transwell system and the Chemicon In Vitro Angiogenesis Assay Kit with CAY10444 (an S1PR3 antagonist), AG1295 (a PDGFR kinase inhibitor) and sc-221226 (an Akt inhibitor) to examine the role of the S1PR3/PDGFR-β/Akt pathway in the S1Pinduced migration and angiogenesis of EPCs.

  15. S1P metabolism in cancer and other pathological conditions.

    PubMed

    Leong, Weng In; Saba, Julie D

    2010-06-01

    Nearly two decades ago, the sphingolipid metabolite sphingosine 1-phosphate was discovered to function as a lipid mediator and regulator of cell proliferation. Since that time, sphingosine 1-phosphate has been shown to mediate a diverse array of fundamental biological processes including cell proliferation, migration, invasion, angiogenesis, vascular maturation and lymphocyte trafficking. Sphingosine 1-phosphate acts primarily via signaling through five ubiquitously expressed G protein-coupled receptors. Intracellular sphingosine 1-phosphate molecules are transported extracellularly and gain access to cognate receptors for autocrine and paracrine signaling and for signaling at distant sites reached through blood and lymphatic circulation systems. Intracellular pools of sphingosine 1-phosphate available for signaling are tightly regulated primarily by three enzymes: sphinosine kinase, S1P lyase and S1P phosphatase. Alterations in sphingosine 1-phosphate as well as the enzymes involved in its synthesis and catabolism have been observed in many types of malignancy. These enzymes are being evaluated for their role in mediating cancer formation and progression, as well as their potential to serve as targets of anti-cancer therapeutics. In this review, the impact of sphingosine 1-phosphate, its cognate receptors, and the enzymes of sphingosine 1-phosphate metabolism on cell survival, apoptosis, autophagy, cellular transformation, invasion, angiogenesis and hypoxia in relation to cancer biology and treatment are discussed.

  16. ASP4058, a Novel Agonist for Sphingosine 1-Phosphate Receptors 1 and 5, Ameliorates Rodent Experimental Autoimmune Encephalomyelitis with a Favorable Safety Profile

    PubMed Central

    Yamamoto, Rie; Okada, Youhei; Hirose, Jun; Koshika, Tadatsura; Kawato, Yuka; Maeda, Masashi; Saito, Rika; Hattori, Kazuyuki; Harada, Hironori; Nagasaka, Yasuhisa; Morokata, Tatsuaki

    2014-01-01

    Sphingosine-1-phosphate (S1P) is a biologically active sphingolipid that acts through the members of a family of five G protein-coupled receptors (S1P1–S1P5). S1P1 is a major regulator of lymphocyte trafficking, and fingolimod, whose active metabolite fingolimod phosphate acts as a nonselective S1P receptor agonist, exerts its immunomodulatory effect, at least in part, by regulating the lymphocyte trafficking by inducing down regulation of lymphocyte S1P1. Here, we detail the pharmacological profile of 5-{5-[3-(trifluoromethyl)-4-{[(2S)-1,1,1-trifluoropropan-2-yl]oxy}phenyl]-1,2,4-oxadiazol-3-yl}-1H-benzimidazole (ASP4058), a novel next-generation S1P receptor agonist selective for S1P1 and S1P5. ASP4058 preferentially activates S1P1 and S1P5 compared with S1P2, 3, 4 in GTPγS binding assays in vitro. Oral administration of ASP4058 reduced the number of peripheral lymphocytes and inhibited the development of experimental autoimmune encephalomyelitis (EAE) in Lewis rats. Further, ASP4058 prevented relapse of disease in a mouse model of relapsing-remitting EAE. Although these immunomodulatory effects were comparable to those of fingolimod, ASP4058 showed a wider safety margin than fingolimod for bradycardia and bronchoconstriction in rodents. These observations suggest that ASP4058 represents a new therapeutic option for treating multiple sclerosis that is safer than nonselective S1P receptor agonists such as fingolimod. PMID:25347187

  17. Altered expression of sphingosine kinase 1 and sphingosine-1-phosphate receptor 1 in mouse hippocampus after kainic acid treatment

    SciTech Connect

    Lee, Dong Hoon; Jeon, Byeong Tak; Jeong, Eun Ae; Kim, Joon Soo; Cho, Yong Woon; Kim, Hyun Joon; Kang, Sang Soo; Cho, Gyeong Jae; Choi, Wan Sung; Roh, Gu Seob

    2010-03-12

    Kainic acid (KA) induces hippocampal cell death and astrocyte proliferation. There are reports that sphingosine kinase (SPHK)1 and sphingosine-1- phosphate (S1P) receptor 1 (S1P{sub 1}) signaling axis controls astrocyte proliferation. Here we examined the temporal changes of SPHK1/S1P{sub 1} in mouse hippocampus during KA-induced hippocampal cell death. Mice were killed at 2, 6, 24, or 48 h after KA (30 mg/kg) injection. There was an increase in Fluoro-Jade B-positive cells in the hippocampus of KA-treated mice with temporal changes of glial fibrillary acidic protein (GFAP) expression. The lowest level of SPHK1 protein expression was found 2 h after KA treatment. Six hours after KA treatment, the expression of SPHK1 and S1P{sub 1} proteins steadily increased in the hippocampus. In immunohistochemical analysis, SPHK1 and S1P{sub 1} are more immunoreactive in astrocytes within the hippocampus of KA-treated mice than in hippocampus of control mice. These results indicate that SPHK1/S1P{sub 1} signaling axis may play an important role in astrocytes proliferation during KA-induced excitotoxicity.

  18. Sphingosine 1-phosphate receptor agonist FTY720-phosphate causes marginal zone B cell displacement.

    PubMed

    Vora, Kalpit A; Nichols, Elizabeth; Porter, Gene; Cui, Yan; Keohane, Carol Ann; Hajdu, Richard; Hale, Jeffery; Neway, William; Zaller, Dennis; Mandala, Suzanne

    2005-08-01

    FTY720 is an immunosuppressive agent that modulates lymphocyte trafficking. It is phosphorylated in vivo to FTY720-phosphate (FTY-P) and binds to a family of G protein-coupled receptors recognizing sphingosine 1-phosphate (S1P) as the natural ligand. It has previously been reported that FTY-P blocks egress of lymphocytes from the thymus and lymph nodes, resulting in peripheral blood lymphopenia. We now report that FTY-P also causes displacement of marginal zone (MZ) B cells to the splenic follicles, an effect that is similar to that observed after in vivo administration of lipopolysaccharide. This effect is specific to B cells in the MZ, as treatment with FTY-P does not cause redistribution of the resident macrophage population. A small but statistically significant decrease in the expression of beta1 integrin on MZ B cells was observed with FTY-P treatment. The redistribution of MZ B cells from the MZ sinuses does not abolish the ability of these cells to respond to the T-independent antigen, trinitrophenol-Ficoll. It has been proposed that the displacement of MZ B cells to the follicles is an indication of cell activation. Consistent with this, FTY-P caused an increase in percentage of MZ B cells expressing activation markers CD9, CD1d, and CD24. These results suggest that S1P receptors on MZ B cells are responsible for their mobilization to follicles.

  19. Exploring amino acids derivatives as potent, selective, and direct agonists of sphingosine-1-phosphate receptor subtype-1.

    PubMed

    Evindar, Ghotas; Deng, Hongfeng; Bernier, Sylvie G; Doyle, Elisabeth; Lorusso, Jeanine; Morgan, Barry A; Westlin, William F

    2013-01-15

    In the quest to discover a potent and selective class of direct agonists to the sphingosine-1-phosphate receptor, we explored the carboxylate functional group as a replacement to previously reported lead phosphates. This has led to the discovery of potent and selective direct agonists with moderate to substantial in vivo lymphopenia. The previously reported selectivity enhancing moiety (SEM) and selectivity enhancing orientation (SEO) in the phenylamide and phenylimidazole scaffolds were crucial to obtaining selectivity for S1P receptor subtype 1 over 3. PMID:23245510

  20. Sphingosine-1-Phosphate/Sphingosine-1-Phosphate Receptor 2 Axis Can Promote Mouse and Human Primary Mast Cell Angiogenic Potential through Upregulation of Vascular Endothelial Growth Factor-A and Matrix Metalloproteinase-2

    PubMed Central

    Chumanevich, Alena; Wedman, Piper; Oskeritzian, Carole A.

    2016-01-01

    Mast cells (MC) are present in most vascularized tissues around the vasculature likely exerting immunomodulatory functions. Endowed with diverse mediators, resident MC represent first-line fine-tuners of local microenvironment. Sphingosine-1-phosphate (S1P) functions as a pluripotent signaling sphingolipid metabolite in health and disease. S1P formation occurs at low levels in resting MC and is upregulated upon activation. Its export can result in type 2 S1P receptor- (S1PR2-) mediated stimulation of MC, further fueling inflammation. However, the role of S1PR2 ligation in proangiogenic vascular endothelial growth factor- (VEGF-) A and matrix metalloproteinase- (MMP-) 2 release from MC is unknown. Using a preclinical MC-dependent model of acute allergic responses and in vitro stimulated primary mouse bone marrow-derived MC (BMMC) or human primary skin MC, we report that S1P signaling resulted in substantial amount of VEGF-A release. Similar experiments using S1pr2-deficient mice or BMMC or selective S1P receptor agonists or antagonists demonstrated that S1P/S1PR2 ligation on MC is important for VEGF-A secretion. Further, we show that S1P stimulation triggered transcriptional upregulation of VEGF-A and MMP-2 mRNA in human but not in mouse MC. S1P exposure also triggered MMP-2 secretion from human MC. These studies identify a novel proangiogenic axis encompassing MC/S1P/S1PR2 likely relevant to inflammation. PMID:26884643

  1. Sphingosine-1-phosphate receptor 2 mediates endothelial cells dysfunction by PI3K-Akt pathway under high glucose condition.

    PubMed

    Liu, Weihua; Liu, Bin; Liu, Shaojun; Zhang, Jingzhi; Lin, Shuangfeng

    2016-04-01

    Endothelial dysfunction is believed the early stage of development of diabetic cardiovascular complications. Sphingosine-1-phosphate (S1P) regulates various biological activities by binding to sphingosine-1-phosphate receptors (S1PRs) including S1PR1-S1PR5. In the present study, the role of S1P receptors in S1P-induced human coronary artery endothelial cells (HCAECs) dysfunction under high glucose condition was investigated and the underlying mechanism was explored. S1PR1-S1PR5 mRNA levels were detected by quantitative Real-time PCR. NO level and polymorphonuclear neutrophils (PMN)-endothelial cells adhesion were measured by nitrate reductase and myeloperoxidase colorimetric method, respectively. Protein levels of endothelial nitric oxide synthase (eNOS), vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1(ICAM-1), phosphatidylinositol 3-kinase (PI3K) and Akt were measured by Western blot analysis. S1PR2 were found the predominant S1P receptor expressed in HCAECs exposed to high glucose. NO level and eNOS activity were remarkably decreased, while PMN adhesion, VCAM-1 and ICAM-1 protein levels were increased significantly by S1P treatment in HCAECs exposed to high glucose and normal glucose. Blockage of S1PR2 with specific antagonist JTE-013 and small interfering RNA (siRNA) resulted in enhanced NO level and eNOS activity as well as decreased PMN adhesion, reduced protein levels of VCAM-1 and ICAM-1 induced by S1P. Furthermore, Phosphor-PI3K and phosphor-Akt level were markedly increased by S1PR2 blockade in S1P-treated cells exposed to high glucose, which were suppressed by PI3K inhibitor wortmannin. In conclusion, S1P/S1PR2 mediated endothelial dysfunction partly by inhibiting PI3K/Akt signaling pathway under high glucose condition. S1PR2 blockage could ameliorate endothelial dysfunction which might provide a potential therapeutic strategy for diabetic vascular complications. PMID:26921757

  2. Ligand-binding pocket shape differences between S1P1 and S1P3 determine efficiency of chemical probe identification by uHTS

    PubMed Central

    Schürer, Stephan C.; Brown, Steven J.; Cabrera, Pedro Gonzales; Schaeffer, Marie-Therese; Chapman, Jacqueline; Jo, Euijung; Chase, Peter; Spicer, Tim; Hodder, Peter; Rosen, Hugh

    2008-01-01

    We have studied the Sphingosine 1-phosphate (S1P) receptor system to better understand why certain molecular targets within a closely related family are much more tractable when identifying compelling chemical leads. Five medically important G protein-coupled receptors for S1P regulate heart rate, coronary artery caliber, endothelial barrier integrity, and lymphocyte trafficking. Selective S1P receptor agonist probes would be of great utility to study receptor subtype-specific function. Through systematic screening of the same libraries, we identified novel selective agonists chemotypes for each of the S1P1 and S1P3 receptors. uHTS for S1P1 was more effective than for S1P3, with many selective, low nanomolar hits of proven mechanism emerging for. Receptor structure modeling and ligand docking reveal differences between the receptor binding pockets, which are the basis for sub-type selectivity. Novel selective agonists interact primarily in the hydrophobic pocket of the receptor in the absence of head-group interactions. Chemistry-space and shape-based analysis of the screening libraries in combination with the binding models explain the observed differential hit rates and enhanced efficiency for lead discovery for S1P1 vs. S1P3 in this closely related receptor family. PMID:18590333

  3. A novel role of sphingosine 1-phosphate receptor S1pr1 in mouse thrombopoiesis

    PubMed Central

    Zhang, Lin; Orban, Martin; Lorenz, Michael; Barocke, Verena; Braun, Daniel; Urtz, Nicole; Schulz, Christian; von Brühl, Marie-Luise; Tirniceriu, Anca; Gaertner, Florian; Proia, Richard L.; Graf, Thomas; Bolz, Steffen-Sebastian; Montanez, Eloi; Prinz, Marco; Müller, Alexandra; von Baumgarten, Louisa; Billich, Andreas; Sixt, Michael; Fässler, Reinhard; von Andrian, Ulrich H.; Junt, Tobias

    2012-01-01

    Millions of platelets are produced each hour by bone marrow (BM) megakaryocytes (MKs). MKs extend transendothelial proplatelet (PP) extensions into BM sinusoids and shed new platelets into the blood. The mechanisms that control platelet generation remain incompletely understood. Using conditional mutants and intravital multiphoton microscopy, we show here that the lipid mediator sphingosine 1-phosphate (S1P) serves as a critical directional cue guiding the elongation of megakaryocytic PP extensions from the interstitium into BM sinusoids and triggering the subsequent shedding of PPs into the blood. Correspondingly, mice lacking the S1P receptor S1pr1 develop severe thrombocytopenia caused by both formation of aberrant extravascular PPs and defective intravascular PP shedding. In contrast, activation of S1pr1 signaling leads to the prompt release of new platelets into the circulating blood. Collectively, our findings uncover a novel function of the S1P–S1pr1 axis as master regulator of efficient thrombopoiesis and might raise new therapeutic options for patients with thrombocytopenia. PMID:23148237

  4. Three different up-titration regimens of ponesimod, an S1P1 receptor modulator, in healthy subjects.

    PubMed

    Scherz, Michael W; Brossard, Patrick; D'Ambrosio, Daniele; Ipek, Murat; Dingemanse, Jasper

    2015-06-01

    Ponesimod is a selective S1P1 receptor modulator, and induces dose-dependent reduction of circulating lymphocytes upon oral dosing. Previous studies showed that single doses up to 75 mg or multiple doses up to 40 mg once daily are well tolerated, and heart rate (HR) reduction and atrio-ventricular conduction delays upon treatment initiation are reduced by gradual up-titration to the maintenance dose. This single-center, open-label, randomized, multiple-dose, 3-treatment, 3-way crossover study compared the tolerability, safety, pharmacokinetics, cardiodynamics, and effects on lymphocytes of 3 different up-titration regimens of ponesimod in healthy male and female subjects. Up-titration regimens comprised escalating periods of b.i.d. dosing (2.5 or 5 mg) and q.d. dosing (10 or 20 mg or both). After the third up-titration period a variable-duration washout period of 1-3 days was followed by re-challenge with a single 20-mg dose of ponesimod. Adverse events were transient and mild to moderate in intensity, not different between regimens. HR decrease after the first dose was greater than after all subsequent doses, including up-titration doses. Little or no HR change was observed with morning doses of b.i.d. regimens, suggesting that 2.5 and 5 mg b.i.d. are sufficient to sustain cardiac desensitization for the 12-hours dosing interval.

  5. Cardiomyocyte S1P1 Receptor–mediated Extracellular Signal–related Kinase Signaling and Desensitization

    PubMed Central

    Tao, Rong; Hoover, Holly E.; Zhang, Jianqing; Honbo, Norman; Alano, Conrad C.; Karliner, Joel S.

    2010-01-01

    We examined the ability of sphingosine-1-phosphate (S1P) to desensitize extracellular signal–related kinase (ERK), a mitogen-activated protein kinase linked to antiapoptotic responses in the heart. In isolated adult mouse cardiomyocytes, S1P (10 nM–5 μM) induced ERK phosphorylation in a time- and dose-dependent manner. S1P stimulation of ERK was completely inhibited by an S1P1/3 subtype receptor antagonist (VPC23019), by a Gi protein inhibitor (pertussis toxin) and by a mitogen-activated protein kinase/ERK kinase inhibitor (PD98059). A selective S1P3 receptor antagonist (CAY10444) had no effect on S1P-induced ERK activation. The selective S1P1 agonist SEW2871 also induced ERK phosphorylation. Activation of ERK by restimulation with 100 nM S1P was suppressed after 1 hour of preincubation with 100 nM S1P but recovered fully the next day, suggesting receptor recycling. Similar results were obtained in protein kinase Cε-null cardiomyocytes. Treatment with the nonselective S1P receptor agonist FTY720 for 1 hour also reduced phospho-ERK expression in response to subsequent S1P stimulation. In contrast to S1P, some desensitization to FTY720 persisted after overnight exposure. Cell death induced by hypoxia/reoxygenation was reduced by pretreatment with exogenous S1P. This enhanced survival was abrogated by pretreatment with PD98059, VPC23019, or pertussis toxin. Thus, exogenous S1P induces rapid and reversible S1P1-mediated ERK phosphorylation. S1P-induced adult mouse cardiomyocyte survival requires ERK activation mediated via an S1P1–Gi pathway. PMID:19433984

  6. G-protein-coupled receptor cell signaling pathways mediating embryonic chick retinal growth cone collapse induced by lysophosphatidic acid and sphingosine-1-phosphate.

    PubMed

    Fincher, Jarod; Whiteneck, Canaan; Birgbauer, Eric

    2014-01-01

    In the development of the nervous system, one of the critical aspects is the proper navigation of axons to their targets, i.e. the problem of axonal guidance. We used the chick visual system as a model to investigate the role of the lysophospholipids lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) as potential axon guidance cues. We showed that both LPA and S1P cause a specific, dose-dependent growth cone collapse of retinal neurons in vitro in the chick model system, with slight differences compared to the mouse but very similar to observations in Xenopus. Because LPA and S1P receptors are G-protein-coupled receptors, we analyzed the intracellular signaling pathways using pharmacological inhibitors in chick retinal neurons. Blocking rho kinase (ROCK) prevented growth cone collapse by LPA and S1P, while blocking PLC or chelating calcium had no effect on growth cone collapse. Inhibition of Gi/o with pertussis toxin resulted in a partial reduction of growth cone collapse, both with LPA and with S1P. Inhibition of p38 blocked growth cone collapse mediated by LPA but not S1P. Thus, in addition to the involvement of the G12/13-ROCK pathway, LPA- and S1P-induced collapse of chick retinal growth cones has a partial requirement for Gi/o. PMID:25138637

  7. Sphingosine kinase-1, S1P transporter spinster homolog 2 and S1P2 mRNA expressions are increased in liver with advanced fibrosis in human

    PubMed Central

    Sato, Masaya; Ikeda, Hitoshi; Uranbileg, Baasanjav; Kurano, Makoto; Saigusa, Daisuke; Aoki, Junken; Maki, Harufumi; Kudo, Hiroki; Hasegawa, Kiyoshi; Kokudo, Norihiro; Yatomi, Yutaka

    2016-01-01

    The role of sphingosine 1-phosphate (S1P) in liver fibrosis or inflammation was not fully examined in human. Controversy exists which S1P receptors, S1P1 and S1P3 vs S1P2, would be importantly involved in its mechanism. To clarify these matters, 80 patients who received liver resection for hepatocellular carcinoma and 9 patients for metastatic liver tumor were enrolled. S1P metabolism was analyzed in background, non-tumorous liver tissue. mRNA levels of sphingosine kinase 1 (SK1) but not SK2 were increased in livers with fibrosis stages 3–4 compared to those with 0–2 and to normal liver. However, S1P was not increased in advanced fibrotic liver, where mRNA levels of S1P transporter spinster homolog 2 (SPNS2) but not S1P-degrading enzymes were enhanced. Furthermore, mRNA levels of S1P2 but not S1P1 or S1P3 were increased in advanced fibrotic liver. These increased mRNA levels of SK1, SPNS2 and S1P2 in fibrotic liver were correlated with α-smooth muscle actin mRNA levels in liver, and with serum ALT levels. In conclusion, S1P may be actively generated, transported to outside the cells, and bind to its specific receptor in human liver to play a role in fibrosis or inflammation. Altered S1P metabolism in fibrotic liver may be their therapeutic target. PMID:27562371

  8. Sphingosine kinase-1, S1P transporter spinster homolog 2 and S1P2 mRNA expressions are increased in liver with advanced fibrosis in human.

    PubMed

    Sato, Masaya; Ikeda, Hitoshi; Uranbileg, Baasanjav; Kurano, Makoto; Saigusa, Daisuke; Aoki, Junken; Maki, Harufumi; Kudo, Hiroki; Hasegawa, Kiyoshi; Kokudo, Norihiro; Yatomi, Yutaka

    2016-01-01

    The role of sphingosine 1-phosphate (S1P) in liver fibrosis or inflammation was not fully examined in human. Controversy exists which S1P receptors, S1P1 and S1P3 vs S1P2, would be importantly involved in its mechanism. To clarify these matters, 80 patients who received liver resection for hepatocellular carcinoma and 9 patients for metastatic liver tumor were enrolled. S1P metabolism was analyzed in background, non-tumorous liver tissue. mRNA levels of sphingosine kinase 1 (SK1) but not SK2 were increased in livers with fibrosis stages 3-4 compared to those with 0-2 and to normal liver. However, S1P was not increased in advanced fibrotic liver, where mRNA levels of S1P transporter spinster homolog 2 (SPNS2) but not S1P-degrading enzymes were enhanced. Furthermore, mRNA levels of S1P2 but not S1P1 or S1P3 were increased in advanced fibrotic liver. These increased mRNA levels of SK1, SPNS2 and S1P2 in fibrotic liver were correlated with α-smooth muscle actin mRNA levels in liver, and with serum ALT levels. In conclusion, S1P may be actively generated, transported to outside the cells, and bind to its specific receptor in human liver to play a role in fibrosis or inflammation. Altered S1P metabolism in fibrotic liver may be their therapeutic target. PMID:27562371

  9. Discovery of Clinical Candidate GSK1842799 As a Selective S1P1 Receptor Agonist (Prodrug) for Multiple Sclerosis

    PubMed Central

    2013-01-01

    To develop effective oral treatment for multiple sclerosis (MS), we discovered a series of alkyl-substituted biaryl amino alcohols as selective S1P1 modulators. One exemplar is (S)-2-amino-2-(5-(4-(octyloxy)-3-(trifluoromethyl)phenyl)-1,3,4-thiadiazol-2-yl)propan-1-ol (10, GSK1842799). Upon phosphorylation, the compound (10-P) showed subnanomole S1P1 agonist activity with >1000× selectivity over S1P3. The alcohol 10 demonstrated good oral bioavailability and rapid in vivo conversion to 10-P. Dosed orally at 0.1 mg/kg, 10 significantly reduced blood lymphocyte counts 6 h postdose, and at 3 mg/kg, 10 achieved efficacy equivalent to FTY720 in the mouse EAE model of MS. Further pharmacokinetic/pharmacodynamic (PK/PD) study with cynomolgus monkeys indicated that, after oral dosing of 10 at 3.8 mg/kg, the active phosphate reached plasma levels that are comparable to FTY-720 phosphate (FTY-P) revealed in human clinical pharmacokinetics studies. On the basis of the favorable in vitro ADME and in vivo PK/PD properties as well as broad toxicology evaluations, compound 10 (GSK1842799) was selected as a candidate for further clinical development. PMID:24900589

  10. Discovery of Clinical Candidate GSK1842799 As a Selective S1P1 Receptor Agonist (Prodrug) for Multiple Sclerosis.

    PubMed

    Deng, Hongfeng; Bernier, Sylvie G; Doyle, Elisabeth; Lorusso, Jeanine; Morgan, Barry A; Westlin, William F; Evindar, Ghotas

    2013-10-10

    To develop effective oral treatment for multiple sclerosis (MS), we discovered a series of alkyl-substituted biaryl amino alcohols as selective S1P1 modulators. One exemplar is (S)-2-amino-2-(5-(4-(octyloxy)-3-(trifluoromethyl)phenyl)-1,3,4-thiadiazol-2-yl)propan-1-ol (10, GSK1842799). Upon phosphorylation, the compound (10-P) showed subnanomole S1P1 agonist activity with >1000× selectivity over S1P3. The alcohol 10 demonstrated good oral bioavailability and rapid in vivo conversion to 10-P. Dosed orally at 0.1 mg/kg, 10 significantly reduced blood lymphocyte counts 6 h postdose, and at 3 mg/kg, 10 achieved efficacy equivalent to FTY720 in the mouse EAE model of MS. Further pharmacokinetic/pharmacodynamic (PK/PD) study with cynomolgus monkeys indicated that, after oral dosing of 10 at 3.8 mg/kg, the active phosphate reached plasma levels that are comparable to FTY-720 phosphate (FTY-P) revealed in human clinical pharmacokinetics studies. On the basis of the favorable in vitro ADME and in vivo PK/PD properties as well as broad toxicology evaluations, compound 10 (GSK1842799) was selected as a candidate for further clinical development. PMID:24900589

  11. HDL-S1P: cardiovascular functions, disease-associated alterations, and therapeutic applications

    PubMed Central

    Levkau, Bodo

    2015-01-01

    Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid contained in High-density lipoproteins (HDL) and has drawn considerable attention in the lipoprotein field as numerous studies have demonstrated its contribution to several functions inherent to HDL. Some of them are partly and some entirely due to the S1P contained in HDL (HDL-S1P). Despite the presence of over 1000 different lipids in HDL, S1P stands out as it possesses its own cell surface receptors through which it exercises key physiological functions. Most of the S1P in human plasma is associated with HDL, and the amount of HDL-S1P influences the quality and quantity of HDL-dependent functions. The main binding partner of S1P in HDL is apolipoprotein M but others may also exist particularly under conditions of acute S1P elevations. HDL not only exercise functions through their S1P content but have also an impact on genuine S1P signaling by influencing S1P bioactivity and receptor presentation. HDL-S1P content is altered in human diseases such as atherosclerosis, coronary artery disease, myocardial infarction, renal insufficiency and diabetes mellitus. Low HDL-S1P has also been linked to impaired HDL functions associated with these disorders. Although the pathophysiological and molecular reasons for such disease-associated shifts in HDL-S1P are little understood, there have been successful approaches to circumvent their adverse implications by pharmacologically increasing HDL-S1P as means to improve HDL function. This mini-review will cover the current understanding of the contribution of HDL-S1P to physiological HDL function, its alteration in disease and ways for its restoration to correct HDL dysfunction. PMID:26539121

  12. Knockdown of the sphingosine-1-phosphate receptor S1PR1 reduces pain behaviors induced by local inflammation of the rat sensory ganglion

    PubMed Central

    Xie, Wenrui; Strong, Judith A.; Kays, Joanne; Nicol, Grant D.; Zhang, Jun-Ming

    2012-01-01

    Sphingosine 1-phosphate (S1P) is a key immune mediator regulating migration of immune cells to sites of inflammation. S1P actions are mediated by a family of five G protein-coupled receptors. Sensory neurons express many of these receptors, and in vitro S1P has excitatory effects on small-diameter sensory neurons, many mediated by the S1P receptor 1 (S1PR1). This study investigated the role of S1P in regulating the sensitivity of DRG neurons. We found that in vivo perfusion of the normal L5 DRG with S1P increased mechanical sensitivity. Microelectrode recordings in isolated whole ganglia showed that large- and medium-diameter cells, as well as small-diameter cells, increased firing in the presence of S1P. To further determine the role of S1PRs, we examined the effects of in vivo S1PR1 knockdown in the L4 and L5 sensory ganglia. Small interfering RNA directed against S1PR1 did not affect baseline mechanical sensitivity in normal animals, in which S1P levels are expected to be low. However, when the L5 ganglion was locally inflamed, a procedure that leads to rapid and sustained mechanical hypersensitivity, S1PR1 siRNA injected animals showed significantly less hypersensitivity than animals injected with scrambled siRNA. Reduced expression of S1PR1, but not S1PR2 or S1PR3, was confirmed with qPCR methods. The results indicate that the S1PR1 receptors in sensory ganglia cells may play an important role in regulating behavioral sensitivity during inflammation. PMID:22445889

  13. Lysophosphatidic acid and sphingosine 1-phosphate metabolic pathways and their receptors are differentially regulated during decidualization of human endometrial stromal cells.

    PubMed

    Brünnert, D; Sztachelska, M; Bornkessel, F; Treder, N; Wolczynski, S; Goyal, P; Zygmunt, M

    2014-10-01

    In the luteal phase, human endometrial stromal cells (HESCs) undergo proliferation, migration and differentiation during the decidualization process under the control of the ovarian steroids progesterone and estrogen. Proper decidualization of stromal cells is required for blastocyst implantation and the development of pregnancy. The proliferation, migration and differentiation of HESCs in decidualization do not require the presence of a blastocyst but are greatly accelerated during implantation. Lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) are potent bioactive lysophospholipids that have critical roles in various physiological and pathophysiological processes, including inflammation, angiogenesis and cancer. The expression of the enzymes involved in LPA and S1P turnover and their receptors in HESCs during decidualization has not been characterized yet. We found that the LPAR1 and LPAR6 and S1PR3 receptors are highly expressed in HESCs. LPAR1, autotaxin (ATX), an LPA producing enzyme and lipid phosphate phosphatase 3 were up-regulated during decidualization. Interestingly, the expression of all S1P receptor subtypes and LPA receptors (LPAR2-6) mRNA was down-regulated after decidualization. We found that SPHK1 is highly expressed in HESCs, and is up-regulated during decidualization. S1P phosphatase SGPP1 and S1P lyase SGPL1 are highly expressed in HESCs. SGPP1 mRNA expression was significantly up-regulated in decidualized HESCs. In conclusion, this study shows the first time that specific LPA and S1P receptors and their metabolizing enzymes are highly regulated in HESCs during decidualization. Furthermore, we suggest that LPAR1 receptor-mediated signaling in HESCs may be crucial in decidualization process. SPHK1 activity and high turnover of S1P and LPA might be essential for precise regulation of their signaling during decidualization of human endometrium and implantation. PMID:24994816

  14. Impairment of Angiogenic Sphingosine Kinase-1/Sphingosine-1-Phosphate Receptors Pathway in Preeclampsia

    PubMed Central

    Dobierzewska, Aneta; Palominos, Macarena; Sanchez, Marianela; Dyhr, Michael; Helgert, Katja; Venegas-Araneda, Pia; Tong, Stephen; Illanes, Sebastian E.

    2016-01-01

    Preeclampsia (PE), is a serious pregnancy disorder characterized in the early gestation by shallow trophoblast invasion, impaired placental neo-angiogenesis, placental hypoxia and ischemia, which leads to maternal and fetal morbidity and mortality. Here we hypothesized that angiogenic sphingosine kinase-1 (SPHK1)/sphingosine-1-phosphate (S1P) receptors pathway is impaired in PE. We found that SPHK1 mRNA and protein expression are down-regulated in term placentae and term chorionic villous explants from patients with PE or severe PE (PES), compared with controls. Moreover, mRNA expression of angiogenic S1PR1 and S1PR3 receptors were decreased in placental samples of PE and PES patients, whereas anti-angiogenic S1PR2 was up-regulated in chorionic villous tissue of PES subjects, pointing to its potential atherogenic and inflammatory properties. Furthermore, in in vitro (JAR cells) and ex vivo (chorionic villous explants) models of placental hypoxia, SPHK1 mRNA and protein were strongly up-regulated under low oxygen tension (1% 02). In contrast, there was no change in SPHK1 expression under the conditions of placental physiological hypoxia (8% 02). In both models, nuclear protein levels of HIF1A were increased at 1% 02 during the time course, but there was no up-regulation at 8% 02, suggesting that SPHK1 and HIF1A might be the part of the same canonical pathway during hypoxia and that both contribute to placental neovascularization during early gestation. Taken together, this study suggest the SPHK1 pathway may play a role in the human early placentation process and may be involved in the pathogenesis of PE. PMID:27284992

  15. Cytokine IL-6 secretion by trophoblasts regulated via sphingosine-1-phosphate receptor 2 involving Rho/Rho-kinase and Rac1 signaling pathways.

    PubMed

    Goyal, Pankaj; Brünnert, Daniela; Ehrhardt, Jens; Bredow, Marike; Piccenini, Svea; Zygmunt, Marek

    2013-08-01

    Various cytokines derived from placental cells are essential for normal placenta development and successful pregnancy. Interleukin-6 (IL-6) is a multifunctional cytokine produced by extravillous and cytotrophoblasts regulating the functions of these cells, e.g. migration, invasion, trophoblast differentiation and proliferation. In macrophages, newly synthesized IL-6 accumulates in the Golgi complex and exits in tubulovesicular carriers fused with recycling endosomes and secreted as a soluble protein. Sphingosine-1-phosphate (S1P) induces various cytokine secretions including IL-6 in different cell types. The signaling mechanisms regulating the IL-6 secretion are unknown. In this study, we found that S1PR2 was the major S1P receptor being expressed in BeWo cells. S1P regulated IL-6 protein secretion in early phase (6 h) and gene expression in later phase (24 h). IL-6 secretion was completely inhibited via inhibitor of transcription (Actinomycin D) or protein synthesis (Cycloheximide) confirming that IL-6 releases constitutively from BeWo cells. By using specific S1PR2 inhibitor JTE-013 and S1PR2 gene silencing, we found that S1PR2 was the main receptor that regulates IL-6 secretion. Furthermore, S1P induced RhoGTPases-dependent pathways that are required for IL-6 secretion. Pretreatment of cells with specific Rho-kinase inhibitor (Y27632) and Rac1 inhibitor (NSC23766) drastically inhibited S1P-induced IL-6 secretion. By using a specific Phosphoinositide 3-kinase (PI3K) inhibitor (LY294002), we found that basal activity of PI3K was required for secretion but was independent of S1P/S1PR2 axis activation. In summary, we report first time that binding of S1P to S1PR2 activates multiple RhoGTPases-dependent pathways that coordinate with PI3K pathway for secretion of IL-6 in BeWo cells.

  16. A Prokaryotic S1P Lyase Degrades Extracellular S1P In Vitro and In Vivo: Implication for Treating Hyperproliferative Disorders

    PubMed Central

    Huwiler, Andrea; Bourquin, Florence; Kotelevets, Nataliya; Pastukhov, Oleksandr; Capitani, Guido; Grütter, Markus G.; Zangemeister-Wittke, Uwe

    2011-01-01

    Sphingosine-1-phosphate (S1P) regulates a broad spectrum of fundamental cellular processes like proliferation, death, migration and cytokine production. Therefore, elevated levels of S1P may be causal to various pathologic conditions including cancer, fibrosis, inflammation, autoimmune diseases and aberrant angiogenesis. Here we report that S1P lyase from the prokaryote Symbiobacterium thermophilum (StSPL) degrades extracellular S1P in vitro and in blood. Moreover, we investigated its effect on cellular responses typical of fibrosis, cancer and aberrant angiogenesis using renal mesangial cells, endothelial cells, breast (MCF-7) and colon (HCT 116) carcinoma cells as disease models. In all cell types, wild-type StSPL, but not an inactive mutant, disrupted MAPK phosphorylation stimulated by exogenous S1P. Functionally, disruption of S1P receptor signaling by S1P depletion inhibited proliferation and expression of connective tissue growth factor in mesangial cells, proliferation, migration and VEGF expression in carcinoma cells, and proliferation and migration of endothelial cells. Upon intravenous injection of StSPL in mice, plasma S1P levels rapidly declined by 70% within 1 h and then recovered to normal 6 h after injection. Using the chicken chorioallantoic membrane model we further demonstrate that also under in vivo conditions StSPL, but not the inactive mutant, inhibited tumor cell-induced angiogenesis as an S1P-dependent process. Our data demonstrate that recombinant StSPL is active under extracellular conditions and holds promise as a new enzyme therapeutic for diseases associated with increased levels of S1P and S1P receptor signaling. PMID:21829623

  17. Full pharmacological efficacy of a novel S1P1 agonist that does not require S1P-like head-group interactions

    PubMed Central

    Gonzalez-Cabrera, Pedro J.; Jo, Euijung; Sanna, M. Germana; Brown, Steven; Leaf, Nora; Marsolais, David; Schaeffer, Marie-Therese; Chapman, Jacqueline; Cameron, Michael; Guerrero, Miguel; Roberts, Edward; Rosen, Hugh

    2008-01-01

    Strong evidence exists for interactions of zwitterionic phosphate and amine groups in Sphingosine-1 phosphate (S1P) to conserved R and E residues present at the extracellular face of transmembrane-3 (TM3) of S1P receptors. The contribution of R120 and E121 for high affinity ligand-receptor interactions is essential, as single-point R120A or E121A S1P1 mutants neither bind S1P nor transduce S1P function. Because S1P receptors are therapeutically interesting, identifying potent selective agonists with different binding modes and in vivo efficacy is of pharmacological importance. Here we describe a modestly water-soluble highly-selective S1P1 agonist (CYM-5442) that does not require R120 or E121 residues for activating S1P1-dependent p42/p44 MAPK phosphorylation, which defines a new hydrophobic pocket in S1P1. CYM-5442 is a full agonist in vitro for S1P1 internalization, phosphorylation and ubiquitination. Importantly, CYM-5442 was a full agonist for induction and maintenance of S1P1-dependent lymphopenia, decreasing B-lymphocytes by 65% and T-lymphocytes by 85% of vehicle. Induction of CYM-5442 lymphopenia was dose and time-dependent, requiring serum concentrations in the 50 nM range. In vitro measures of S1P1 activation by CYM-5442 were non-competitively inhibited by a specific S1P1 antagonist (W146), competitive for S1P, FTY720-P and SEW2871. In addition, lymphopenia by CYM-5442 was reversed by W146 administration or upon pharmacokinetic agonist clearance. Pharmacokinetics in mice also indicated that CYM-5442 partitions significantly in central nervous tissue. These data show that CYM-5442 activates S1P1-dependent pathways in vitro and to levels of full efficacy in vivo through a hydrophobic pocket, separable from the orthosteric site of S1P binding that is headgroup dependent. PMID:18708635

  18. Sphingosine 1-Phosphate Receptor 2 and 3 Mediate Bone Marrow-Derived Monocyte/Macrophage Motility in Cholestatic Liver Injury in Mice

    PubMed Central

    Yang, Le; Han, Zhen; Tian, Lei; Mai, Ping; Zhang, Yuanyuan; Wang, Lin; Li, Liying

    2015-01-01

    Sphingosine 1-phosphate (S1P)/S1P receptor (S1PR) system has been implicated in the pathological process of liver injury. This study was designed to evaluate the effects of S1P/S1PR on bone marrow-derived monocyte/macrophage (BMM) migration in mouse models of cholestatic liver injury, and identify the signaling pathway underlying this process. S1PR1–3 expression in BMM was characterized by immunofluorescence, RT-PCR and Western blot. Cell migration was determined in Boyden chambers. In vivo, the chimera mice, which received BM transplants from EGFP-transgenic mice, received an operation of bile duct ligation (BDL) to induce liver injury with the administration of S1PR2/3 antagonists. The results showed that S1PR1–3 were all expressed in BMMs. S1P exerted a powerful migratory action on BMMs via S1PR2 and S1PR3. Furthermore, PTX and LY-294002 (PI3K inhibitor) prevented S1PR2/3-mediated BMM migration, and Rac1 activation by S1P was inhibited by JTE-013, CAY-10444 or LY294002. Administration of S1PR2/3 antagonists in vivo significantly reduced BMM recruitment in BDL-treated mice, and attenuated hepatic inflammation and fibrosis. In conclusion, S1P/S1PR2/3 system mediates BMM motility by PTX-PI3K-Rac1 signaling pathway, which provides new compelling information on the role of S1P/S1PR in liver injury and opens new perspectives for the pharmacological treatment of hepatic fibrosis. PMID:26324256

  19. Analysis of Onset Mechanisms of a Sphingosine 1-Phosphate Receptor Modulator Fingolimod-Induced Atrioventricular Conduction Block and QT-Interval Prolongation

    SciTech Connect

    Yagi, Yukihiro; Nakamura, Yuji; Kitahara, Ken; Harada, Takuma; Kato, Kazuhiko; Ninomiya, Tomohisa; Cao, Xin; Ohara, Hiroshi; Izumi-Nakaseko, Hiroko; Suzuki, Kokichi; Ando, Kentaro; and others

    2014-11-15

    Fingolimod, a sphingosine 1-phosphate (S1P) receptor subtype 1, 3, 4 and 5 modulator, has been used for the treatment of patients with relapsing forms of multiple sclerosis, but atrioventricular conduction block and/or QT-interval prolongation have been reported in some patients after the first dose. In this study, we directly compared the electropharmacological profiles of fingolimod with those of siponimod, a modulator of sphingosine 1-phosphate receptor subtype 1 and 5, using in vivo guinea-pig model and in vitro human ether-a-go-go-related gene (hERG) assay to better understand the onset mechanisms of the clinically observed adverse events. Fingolimod (0.01 and 0.1 mg/kg) or siponimod (0.001 and 0.01 mg/kg) was intravenously infused over 10 min to the halothane-anaesthetized guinea pigs (n = 4), whereas the effects of fingolimod (1 μmol/L) and siponimod (1 μmol/L) on hERG current were examined (n = 3). The high doses of fingolimod and siponimod induced atrioventricular conduction block, whereas the low dose of siponimod prolonged PR interval, which was not observed by that of fingolimod. The high dose of fingolimod prolonged QT interval, which was not observed by either dose of siponimod. Meanwhile, fingolimod significantly inhibited hERG current, which was not observed by siponimod. These results suggest that S1P receptor subtype 1 in the heart could be one of the candidates for fingolimod- and siponimod-induced atrioventricular conduction block since S1P receptor subtype 5 is localized at the brain, and that direct I{sub Kr} inhibition may play a key role in fingolimod-induced QT-interval prolongation. - Highlights: • Fingolimod and siponimod are S1P{sub 1,3,4,5} and S1P{sub 1,5} receptor modulators, respectively. • Fingolimod and siponimod induced AV block in the halothane-anesthetized guinea pigs. • S1P{sub 1} in the hearts may be the target of fingolimod- and siponimod-induced AV block. • Fingolimod directly inhibited hERG current, which was not

  20. Sphingosine 1-phosphate in metabolic syndrome (Review).

    PubMed

    Chen, Wei; Lu, Hongwei; Yang, Jie; Xiang, Hong; Peng, Hui

    2016-10-01

    Metabolic syndrome (MetS), a clustering of components, is closely associated with the development and prognosis of cardiovascular disease and diabetes. Sphingosine 1-phosphate (S1P) is a lysophospholipid with paracrine and autocrine effects, which is associated with obesity, insulin resistance, hyperglycemia, dyslipidemia and hypertension through extracellular and intracellular signals to achieve a variety of biological functions. However, there is controversy regarding the role of S1P in MetS; the specific role played by S1P remains unclear. It ameliorates abnormal energy metabolism and deviant adipogenesis and mediates inflammation in obesity. Despite the fact that sphingosine kinase (SphK)2/S1P increases the glucose‑stimulated insulin secretion of β-cells, more evidence showed that activation of the SphK1/S1P/S1P2R pathway inhibited the feedback loop of insulin secretion and sensitivity. The majority of S1P1R activation improves diabetes whereas S1P2R activation worsens the condition. In hyperlipidemia, S1P binds to high-density lipoprotein, low‑density lipoprotein and very low-density lipoprotein exerting different effects. Moreover, low concentrations of S1P lead to vasodilation whereas high concentrations of S1P result in vasocontraction of isolated arterioles. This review discusses the means by which different SphKs, S1P concentrations or S1P receptor subtypes results to diverse result in MetS, and then examines the role of S1P in MetS. PMID:27600830

  1. Animal Model of Respiratory Syncytial Virus: CD8+ T Cells Cause a Cytokine Storm That Is Chemically Tractable by Sphingosine-1-Phosphate 1 Receptor Agonist Therapy

    PubMed Central

    Walsh, Kevin B.; Teijaro, John R.; Brock, Linda G.; Fremgen, Daniel M.; Collins, Peter L.

    2014-01-01

    ABSTRACT The cytokine storm is an intensified, dysregulated, tissue-injurious inflammatory response driven by cytokine and immune cell components. The cytokine storm during influenza virus infection, whereby the amplified innate immune response is primarily responsible for pulmonary damage, has been well characterized. Now we describe a novel event where virus-specific T cells induce a cytokine storm. The paramyxovirus pneumonia virus of mice (PVM) is a model of human respiratory syncytial virus (hRSV). Unexpectedly, when C57BL/6 mice were infected with PVM, the innate inflammatory response was undetectable until day 5 postinfection, at which time CD8+ T cells infiltrated into the lung, initiating a cytokine storm by their production of gamma interferon (IFN-γ) and tumor necrosis factor alpha (TNF-α). Administration of an immunomodulatory sphingosine-1-phosphate (S1P) receptor 1 (S1P1R) agonist significantly inhibited PVM-elicited cytokine storm by blunting the PVM-specific CD8+ T cell response, resulting in diminished pulmonary disease and enhanced survival. IMPORTANCE A dysregulated overly exuberant immune response, termed a “cytokine storm,” accompanies virus-induced acute respiratory diseases (VARV), is primarily responsible for the accompanying high morbidity and mortality, and can be controlled therapeutically in influenza virus infection of mice and ferrets by administration of sphingosine-1-phosphate 1 receptor (S1P1R) agonists. Here, two novel findings are recorded. First, in contrast to influenza infection, where the cytokine storm is initiated early by the innate immune system, for pneumonia virus of mice (PVM), a model of RSV, the cytokine storm is initiated late in infection by the adaptive immune response: specifically, by virus-specific CD8 T cells via their release of IFN-γ and TNF-α. Blockading these cytokines with neutralizing antibodies blunts the cytokine storm and protects the host. Second, PVM infection is controlled by administration

  2. Sphingosine 1-phosphate in blood: function, metabolism, and fate.

    PubMed

    Thuy, Andreas V; Reimann, Christina-Maria; Hemdan, Nasr Y A; Gräler, Markus H

    2014-01-01

    Sphingosine 1-phosphate (S1P) is a lipid metabolite and a ligand of five G protein-coupled cell surface receptors S1PR1 to S1PR5. These receptors are expressed on various cells and cell types of the immune, cardiovascular, respiratory, hepatic, reproductive, and neurologic systems, and S1P has an impact on many different pathophysiological conditions including autoimmune, cardiovascular, and neurodegenerative diseases, cancer, deafness, osteogenesis, and reproduction. While these diverse signalling properties of S1P have been extensively reviewed, the particular role of S1P in blood is still a matter of debate. Blood contains the highest S1P concentration of all body compartments, and several questions are still not sufficiently answered: Where does it come from and how is it metabolized? Why is the concentration of S1P in blood so high? Are minor changes of the high blood S1P concentrations physiologically relevant? Do blood cells and vascular endothelial cells that are constantly exposed to high blood S1P levels still respond to S1P via S1P receptors? Recent data reveal new insights into the functional role and the metabolic fate of blood-borne S1P. This review aims to summarize our current knowledge regarding the source, secretion, transportation, function, metabolism, and fate of S1P in blood. PMID:24977489

  3. Sphingosine 1-phosphate signaling impacts lymphocyte migration, inflammation and infection.

    PubMed

    Tiper, Irina V; East, James E; Subrahmanyam, Priyanka B; Webb, Tonya J

    2016-08-01

    Sphingosine 1-phosphate (S1P) is a sphingosine containing lipid intermediate obtained from ceramide. S1P is known to be an important signaling molecule and plays multiple roles in the context of immunity. This lysophospholipid binds and activates G-protein-coupled receptors (GPCRs) known as S1P receptors 1-5 (S1P1-5). Once activated, these GPCRs mediate signaling that can lead to alterations in cell proliferation, survival or migration, and can also have other effects such as promoting angiogenesis. In this review, we will present evidence demonstrating a role for S1P in lymphocyte migration, inflammation and infection, as well as in cancer. The therapeutic potential of targeting S1P receptors, kinases and lyase will also be discussed. PMID:27354294

  4. Hypothalamic S1P/S1PR1 axis controls energy homeostasis.

    PubMed

    Silva, Vagner R R; Micheletti, Thayana O; Pimentel, Gustavo D; Katashima, Carlos K; Lenhare, Luciene; Morari, Joseane; Mendes, Maria Carolina S; Razolli, Daniela S; Rocha, Guilherme Z; de Souza, Claudio T; Ryu, Dongryeol; Prada, Patrícia O; Velloso, Lício A; Carvalheira, José B C; Pauli, José Rodrigo; Cintra, Dennys E; Ropelle, Eduardo R

    2014-01-01

    Sphingosine 1-phosphate receptor 1 (S1PR1) is a G-protein-coupled receptor for sphingosine-1-phosphate (S1P) that has a role in many physiological and pathophysiological processes. Here we show that the S1P/S1PR1 signalling pathway in hypothalamic neurons regulates energy homeostasis in rodents. We demonstrate that S1PR1 protein is highly enriched in hypothalamic POMC neurons of rats. Intracerebroventricular injections of the bioactive lipid, S1P, reduce food consumption and increase rat energy expenditure through persistent activation of STAT3 and the melanocortin system. Similarly, the selective disruption of hypothalamic S1PR1 increases food intake and reduces the respiratory exchange ratio. We further show that STAT3 controls S1PR1 expression in neurons via a positive feedback mechanism. Interestingly, several models of obesity and cancer anorexia display an imbalance of hypothalamic S1P/S1PR1/STAT3 axis, whereas pharmacological intervention ameliorates these phenotypes. Taken together, our data demonstrate that the neuronal S1P/S1PR1/STAT3 signalling axis plays a critical role in the control of energy homeostasis in rats. PMID:25255053

  5. A rational utilization of high-throughput screening affords selective, orally bioavailable 1-benzyl-3-carboxyazetidine sphingosine-1-phosphate-1 receptor agonists.

    PubMed

    Hale, Jeffrey J; Lynch, Christopher L; Neway, William; Mills, Sander G; Hajdu, Richard; Keohane, Carol Ann; Rosenbach, Mark J; Milligan, James A; Shei, Gan-Ju; Parent, Stephen A; Chrebet, Gary; Bergstrom, James; Card, Deborah; Ferrer, Marc; Hodder, Peter; Strulovici, Berta; Rosen, Hugh; Mandala, Suzanne

    2004-12-30

    Moderately potent, selective S1P(1) receptor agonists identified from high-throughput screening have been adapted into lipophilic tails for a class of orally bioavailable amino acid-based S1P(1) agonists represented by 7. Many of the new compounds are potent S1P(1) agonists that select against the S1P(2), S1P(3), and S1P(4) (although not S1P(5)) receptor subtypes. Analogues 18 and 24 are highly orally bioavailable and possess excellent pharmacokinetic profiles in the rat, dog, and rhesus monkey.

  6. Critical role of sphingosine-1-phosphate receptor-2 in the disruption of cerebrovascular integrity in experimental stroke

    PubMed Central

    Kim, Gab Seok; Yang, Li; Zhang, Guoqi; Zhao, Honggang; Selim, Magdy; McCullough, Louise D.; Kluk, Michael J.; Sanchez, Teresa

    2015-01-01

    The use and effectiveness of current stroke reperfusion therapies are limited by the complications of reperfusion injury, which include increased cerebrovascular permeability and haemorrhagic transformation. Sphingosine-1-phosphate (S1P) is emerging as a potent modulator of vascular integrity via its receptors (S1PR). By using genetic approaches and a S1PR2 antagonist (JTE013), here we show that S1PR2 plays a critical role in the induction of cerebrovascular permeability, development of intracerebral haemorrhage and neurovascular injury in experimental stroke. In addition, inhibition of S1PR2 results in decreased matrix metalloproteinase (MMP)-9 activity in vivo and lower gelatinase activity in cerebral microvessels. S1PR2 immunopositivity is detected only in the ischemic microvessels of wild-type mice and in the cerebrovascular endothelium of human brain autopsy samples. In vitro, S1PR2 potently regulates the responses of the brain endothelium to ischaemic and inflammatory injury. Therapeutic targeting of this novel pathway could have important translational relevance to stroke patients. PMID:26243335

  7. Engineering in vivo gradients of sphingosine-1-phosphate receptor ligands for localized microvascular remodeling and inflammatory cell positioning.

    PubMed

    Ogle, Molly E; Sefcik, Lauren S; Awojoodu, Anthony O; Chiappa, Nathan F; Lynch, Kevin; Peirce-Cottler, Shayn; Botchwey, Edward A

    2014-11-01

    Biomaterial-mediated controlled release of soluble signaling molecules is a tissue engineering approach to spatially control processes of inflammation, microvascular remodeling and host cell recruitment, and to generate biochemical gradients in vivo. Lipid mediators, such as sphingosine 1-phosphate (S1P), are recognized for their essential roles in spatial guidance, signaling and highly regulated endogenous gradients. S1P and pharmacological analogs such as FTY720 are therapeutically attractive targets for their critical roles in the trafficking of cells between blood and tissue spaces, both physiologically and pathophysiologically. However, the interaction of locally delivered sphingolipids with the complex metabolic networks controlling the flux of lipid species in inflamed tissue has yet to be elucidated. In this study, complementary in vitro and in vivo approaches are investigated to identify relationships between polymer composition, drug release kinetics, S1P metabolic activity, signaling gradients and spatial positioning of circulating cells around poly(lactic-co-glycolic acid) biomaterials. Results demonstrate that biomaterial-based gradients of S1P are short-lived in the tissue due to degradation by S1P lyase, an enzyme that irreversibly degrades intracellular S1P. On the other hand, in vivo gradients of the more stable compound, FTY720, enhance microvascular remodeling by selectively recruiting an anti-inflammatory subset of monocytes (S1P3(high)) to the biomaterial. Results highlight the need to better understand the endogenous balance of lipid import/export machinery and lipid kinase/phosphatase activity in order to design biomaterial products that spatially control the innate immune environment to maximize regenerative potential. PMID:25128750

  8. Engagement of S1P1-degradative mechanisms leads to vascular leak in mice

    PubMed Central

    Oo, Myat Lin; Chang, Sung-Hee; Thangada, Shobha; Wu, Ming-Tao; Rezaul, Karim; Blaho, Victoria; Hwang, Sun-Il; Han, David K.; Hla, Timothy

    2011-01-01

    GPCR inhibitors are highly prevalent in modern therapeutics. However, interference with complex GPCR regulatory mechanisms leads to both therapeutic efficacy and adverse effects. Recently, the sphingosine-1-phosphate (S1P) receptor inhibitor FTY720 (also known as Fingolimod), which induces lymphopenia and prevents neuroinflammation, was adopted as a disease-modifying therapeutic in multiple sclerosis. Although highly efficacious, dose-dependent increases in adverse events have tempered its utility. We show here that FTY720P induces phosphorylation of the C-terminal domain of S1P receptor 1 (S1P1) at multiple sites, resulting in GPCR internalization, polyubiquitinylation, and degradation. We also identified the ubiquitin E3 ligase WWP2 in the GPCR complex and demonstrated its requirement in FTY720-induced receptor degradation. GPCR degradation was not essential for the induction of lymphopenia, but was critical for pulmonary vascular leak in vivo. Prevention of receptor phosphorylation, internalization, and degradation inhibited vascular leak, which suggests that discrete mechanisms of S1P receptor regulation are responsible for the efficacy and adverse events associated with this class of therapeutics. PMID:21555855

  9. A novel lipid natriuretic factor in the renal medulla: sphingosine-1-phosphate.

    PubMed

    Zhu, Qing; Xia, Min; Wang, Zhengchao; Li, Pin-Lan; Li, Ningjun

    2011-07-01

    Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid metabolite formed by phosphorylation of sphingosine. S1P has been indicated to play a significant role in the cardiovascular system. It has been shown that the enzymes for S1P metabolism are expressed in the kidneys. The present study characterized the expression of S1P receptors in the kidneys and determined the role of S1P in the control of renal hemodynamics and sodium excretion. Real-time RT-PCR analyses showed that S1P receptors S1P1, S1P2, and S1P3 were most abundantly expressed in the renal medulla. Immunohistochemistry revealed that all three types of S1P receptors were mainly located in collecting ducts. Intramedullary infusion of FTY720, an S1P agonist, produced a dramatic increase in sodium excretion by twofold and a small but significant increase in medullary blood flow (16%). Administration of W146, an S1P1 antagonist, into the renal medulla blocked the effect of FTY720 and decreased the sodium excretion by 37% when infused alone. The antagonists of S1P2 and S1P3 had no effect. FTY720 produced additive natriuretic effects in combination with different sodium transporter inhibitors except amiloride, an epithelial sodium channel blocker. In the presence of nitric oxide synthase inhibitor l-NAME, FTY720 still increased sodium excretion. These data suggest that S1P produces natriuretic effects via activation of S1P1 in the renal medulla and this natriuretic effect may be through inhibition of epithelial sodium channel, which is nitric oxide independent. It is concluded that S1P is a novel diuretic factor in the renal medulla and may be an important regulator of sodium homeostasis.

  10. Implication of sphingosin-1-phosphate in cardiovascular regulation

    PubMed Central

    Li, Ningjun; Zhang, Fan

    2016-01-01

    Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid metabolite generated by phosphorylation of sphingosine catalyzed by sphingosine kinase. S1P acts mainly through its high affinity G-protein-coupled receptors and participates in the regulation of multiple systems, including cardiovascular system. It has been shown that S1P signaling is involved in the regulation of cardiac chronotropy and inotropy and contributes to cardioprotection as well as cardiac remodeling; S1P signaling regulates vascular function, such as vascular tone and endothelial barrier, and possesses an anti-atherosclerotic effect; S1P signaling is also implicated in the regulation of blood pressure. Therefore, manipulation of S1P signaling may offer novel therapeutic approaches to cardiovascular diseases. As several S1P receptor modulators and sphingosine kinase inhibitors have been approved or under clinical trials for the treatment of other diseases, it may expedite the test and implementation of these S1P-based drugs in cardiovascular diseases. PMID:27100508

  11. Sphingosine-1-phosphate transporters as targets for cancer therapy.

    PubMed

    Nagahashi, Masayuki; Takabe, Kazuaki; Terracina, Krista P; Soma, Daiki; Hirose, Yuki; Kobayashi, Takashi; Matsuda, Yasunobu; Wakai, Toshifumi

    2014-01-01

    Sphingosine-1-phosphate (S1P) is a pleiotropic lipid mediator that regulates cell survival, migration, the recruitment of immune cells, angiogenesis, and lymphangiogenesis, all of which are involved in cancer progression. S1P is generated inside cancer cells by sphingosine kinases then exported outside of the cell into the tumor microenvironment where it binds to any of five G protein coupled receptors and proceeds to regulate a variety of functions. We have recently reported on the mechanisms underlying the "inside-out" signaling of S1P, its export through the plasma membrane, and its interaction with cell surface receptors. Membrane lipids, including S1P, do not spontaneously exchange through lipid bilayers since the polar head groups do not readily go through the hydrophobic interior of the plasma membrane. Instead, specific transporter proteins exist on the membrane to exchange these lipids. This review summarizes what is known regarding S1P transport through the cell membrane via ATP-binding cassette transporters and the spinster 2 transporter and discusses the roles for these transporters in cancer and in the tumor microenvironment. Based on our research and the emerging understanding of the role of S1P signaling in cancer and in the tumor microenvironment, S1P transporters and S1P signaling hold promise as new therapeutic targets for cancer drug development. PMID:25133174

  12. GPCR cell signaling pathways mediating embryonic chick retinal growth cone collapse induced by LPA and S1P

    PubMed Central

    Fincher, Jarod; Whiteneck, Canaan; Birgbauer, Eric

    2014-01-01

    In the development of the nervous system, one of the critical aspects is the proper navigation of axons to their targets, the problem of axonal guidance. We are using the chick visual system as a model to investigate the role of the lysophospholipids lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) as potential axon guidance cues. We show that both LPA and S1P cause specific, dose-dependent growth cone collapse of retinal neurons in vitro in the chick model system, with slight differences to mouse, but very similar to Xenopus. Because LPA and S1P receptors are GPCRs, we analyzed the intracellular signaling pathways using pharmacological inhibitors in chick retinal neurons. Blocking rho kinase (ROCK) prevented growth cone collapse by LPA and S1P, while blocking PLC or chelating calcium had no effect on growth cone collapse. Inhibiting Gi/o with pertussis toxin resulted in a partial reduction of growth cone collapse, both with LPA and S1P. Inhibition of p38 blocked growth cone collapse mediated by LPA but not S1P. Thus, in addition to the involvement of the G12/13-ROCK pathway, LPA and S1P induced collapse of chick retinal growth cones has a partial requirement for Gi/o. PMID:25138637

  13. Sphingosine kinase 1/sphingosine 1-phosphate signalling pathway as a potential therapeutic target of pulmonary hypertension

    PubMed Central

    Xing, Xi-Qian; Li, Yan-Li; Zhang, Yu-Xuan; Xiao, Yi; Li, Zhi-Dong; Liu, Li-Qiong; Zhou, Yu-Shan; Zhang, Hong-Yan; Liu, Yan-Hong; Zhang, Li-Hui; Zhuang, Min; Chen, Yan-Ping; Ouyang, Sheng-Rong; Wu, Xu-Wei; Yang, Jiao

    2015-01-01

    Pulmonary hypertension is characterized by extensive vascular remodelling, leading to increased pulmonary vascular resistance and eventual death due to right heart failure. The pathogenesis of pulmonary hypertension involves vascular endothelial dysfunction and disordered vascular smooth muscle cell (VSMC) proliferation and migration, but the exact processes remain unknown. Sphingosine 1-phosphate (S1P) is a bioactive lysophospholipid involved in a wide spectrum of biological processes. S1P has been shown to regulate VSMC proliferation and migration and vascular tension via a family of five S1P G-protein-coupled receptors (S1P1-SIP5). S1P has been shown to have both a vasoconstrictive and vasodilating effect. The S1P receptors S1P1 and S1P3 promote, while S1P2 inhibits VSMC proliferation and migration in vitro in response to S1P. Moreover, it has been reported recently that sphingosine kinase 1 and S1P2 inhibitors might be useful therapeutic agents in the treatment of empirical pulmonary hypertension. The sphingosine kinase 1/S1P signalling pathways may play a role in the pathogenesis of pulmonary hypertension. Modulation of this pathway may offer novel therapeutic strategies. PMID:26550106

  14. Sphingosine kinase 1/sphingosine 1-phosphate signalling pathway as a potential therapeutic target of pulmonary hypertension.

    PubMed

    Xing, Xi-Qian; Li, Yan-Li; Zhang, Yu-Xuan; Xiao, Yi; Li, Zhi-Dong; Liu, Li-Qiong; Zhou, Yu-Shan; Zhang, Hong-Yan; Liu, Yan-Hong; Zhang, Li-Hui; Zhuang, Min; Chen, Yan-Ping; Ouyang, Sheng-Rong; Wu, Xu-Wei; Yang, Jiao

    2015-01-01

    Pulmonary hypertension is characterized by extensive vascular remodelling, leading to increased pulmonary vascular resistance and eventual death due to right heart failure. The pathogenesis of pulmonary hypertension involves vascular endothelial dysfunction and disordered vascular smooth muscle cell (VSMC) proliferation and migration, but the exact processes remain unknown. Sphingosine 1-phosphate (S1P) is a bioactive lysophospholipid involved in a wide spectrum of biological processes. S1P has been shown to regulate VSMC proliferation and migration and vascular tension via a family of five S1P G-protein-coupled receptors (S1P1-SIP5). S1P has been shown to have both a vasoconstrictive and vasodilating effect. The S1P receptors S1P1 and S1P3 promote, while S1P2 inhibits VSMC proliferation and migration in vitro in response to S1P. Moreover, it has been reported recently that sphingosine kinase 1 and S1P2 inhibitors might be useful therapeutic agents in the treatment of empirical pulmonary hypertension. The sphingosine kinase 1/S1P signalling pathways may play a role in the pathogenesis of pulmonary hypertension. Modulation of this pathway may offer novel therapeutic strategies. PMID:26550106

  15. The clinically-tested S1P receptor agonists, FTY720 and BAF312, demonstrate subtype-specific bradycardia (S1P₁) and hypertension (S1P₃) in rat.

    PubMed

    Fryer, Ryan M; Muthukumarana, Akalushi; Harrison, Paul C; Nodop Mazurek, Suzanne; Chen, Rong Rhonda; Harrington, Kyle E; Dinallo, Roger M; Horan, Joshua C; Patnaude, Lori; Modis, Louise K; Reinhart, Glenn A

    2012-01-01

    Sphingosine-1-phospate (S1P) and S1P receptor agonists elicit mechanism-based effects on cardiovascular function in vivo. Indeed, FTY720 (non-selective S1P(X) receptor agonist) produces modest hypertension in patients (2-3 mmHg in 1-yr trial) as well as acute bradycardia independent of changes in blood pressure. However, the precise receptor subtypes responsible is controversial, likely dependent upon the cardiovascular response in question (e.g. bradycardia, hypertension), and perhaps even species-dependent since functional differences in rodent, rabbit, and human have been suggested. Thus, we characterized the S1P receptor subtype specificity for each compound in vitro and, in vivo, the cardiovascular effects of FTY720 and the more selective S1P₁,₅ agonist, BAF312, were tested during acute i.v. infusion in anesthetized rats and after oral administration for 10 days in telemetry-instrumented conscious rats. Acute i.v. infusion of FTY720 (0.1, 0.3, 1.0 mg/kg/20 min) or BAF312 (0.5, 1.5, 5.0 mg/kg/20 min) elicited acute bradycardia in anesthetized rats demonstrating an S1P₁ mediated mechanism-of-action. However, while FTY720 (0.5, 1.5, 5.0 mg/kg/d) elicited dose-dependent hypertension after multiple days of oral administration in rat at clinically relevant plasma concentrations (24-hr mean blood pressure = 8.4, 12.8, 16.2 mmHg above baseline vs. 3 mmHg in vehicle controls), BAF312 (0.3, 3.0, 30.0 mg/kg/d) had no significant effect on blood pressure at any dose tested suggesting that hypertension produced by FTY720 is mediated S1P₃ receptors. In summary, in vitro selectivity results in combination with studies performed in anesthetized and conscious rats administered two clinically tested S1P agonists, FTY720 or BAF312, suggest that S1P₁ receptors mediate bradycardia while hypertension is mediated by S1P₃ receptor activation. PMID:23285242

  16. Effects of sphingosine-1-phosphate receptor 1 phosphorylation in response to FTY720 during neuroinflammation

    PubMed Central

    Huang, Yingxiang; Garris, Christopher S.; Moreno, Monica A.; Griffin, Christina W.; Han, May H.

    2016-01-01

    Fingolimod (FTY720, Gilenya), a sphingosine-1-phosphate receptor (S1PR) modulator, is one of the first-line immunomodulatory therapies for treatment of relapsing-remitting multiple sclerosis (MS). Human S1PR1 variants have been reported to have functional heterogeneity in vitro, suggesting that S1PR1 function may influence FTY720 efficacy. In this study, we examined the influence of S1PR1 phosphorylation on response to FTY720 in neuroinflammation. We found that mice carrying a phosphorylation-defective S1pr1 gene [S1PR1(S5A) mice] were refractory to FTY720 treatment in MOG35-55-immunized and Th17-mediated experimental autoimmune encephalomyelitis (EAE) models. Long-term treatment with FTY720 induced significant lymphopenia and suppressed Th17 response in the peripheral immune system via downregulating STAT3 phosphorylation in both WT and S1PR1(S5A) mice. However, FTY720 did not effectively prevent neuroinflammation in the S1PR1(S5A) EAE mice as a result of encephalitogenic cells expressing C-C chemokine receptor 6 (CCR6). Combined treatment with FTY720 and anti-CCR6 delayed disease progression in S1PR1(S5A) EAE mice, suggesting that CCR6-mediated cell trafficking can overcome the effects of FTY720. This work may have translational relevance regarding FTY720 efficacy in MS patients and suggests that cell type–specific therapies may enhance therapeutic efficacy in MS.

  17. The sphingosine 1-phosphate receptor agonist FTY720 is neuroprotective after cuprizone-induced CNS demyelination

    PubMed Central

    Slowik, A; Schmidt, T; Beyer, C; Amor, S; Clarner, T; Kipp, M

    2015-01-01

    BACKGROUND AND PURPOSE Modulation of the sphingosine 1-phosphate receptor is an approved treatment for relapsing multiple sclerosis because of its anti-inflammatory effect of retaining lymphocytes within the lymph nodes. Here, we evaluated the potential of an agonist at this receptor, FTY720 (fingolimod), to activate the promyelinating pathways within the brain to encourage remyelination and neuroprotection. EXPERIMENTAL APPROACH In this study, we used the cuprizone model in male C57BL/6 mice and tested the promyelinating and neuroprotective effects of FTY720 after acute and chronic toxin-induced experimental demyelination. We used histological, immunohistochemical and gene expression methods. KEY RESULTS The midline of the corpus callosum was severely demyelinated after acute and chronic cuprizone-induced demyelination. Robust endogenous remyelination was evident after acute, but impaired after chronic, demyelination. FTY720 treatment modestly accelerated myelin recovery after acute but not chronic cuprizone exposure. Markers of gliosis (astrocyte and microglia activation) were not affected by FTY720 treatment. Remarkably, the accumulation of amyloid precursor protein-positive spheroids in axons was less distinct in FTY720-treated animals, indicating that this compound alleviated ongoing axonal damage. CONCLUSIONS AND IMPLICATIONS We show that even during endogenous remyelination, axonal degeneration continued at a low level, accumulating over time. This continuous neurodegenerative process was ameliorated by FTY720 treatment. FTY720 preserved CNS integrity by direct interaction with brain resident cells, the actions of which are still to be defined. PMID:25220526

  18. Asymmetric Synthesis of Conformationally Constrained Fingolimod Analogues—Discovery of an Orally Active Sphingosine 1-Phosphate Receptor Type-1 Agonist and Receptor Type-3 Antagonist

    PubMed Central

    Zhu, Ran; Snyder, Ashley H.; Kharel, Yugesh; Schaffter, Lisa; Sun, Qin; Kennedy, Perry C.; Lynch, Kevin R.; Macdonald, Timothy L.

    2010-01-01

    Compound 1 (FTY720, Fingolimod) represents a new generation of immunosuppressant that modulates lymphocyte trafficking by interacting with the S1P1 receptor. Compound 1 also provides a template molecule for studying the molecular biology of S1P receptors and related enzymes (kinases and phosphatases). In this study, two conformationally constrained analogues of 1 (3a and 3c) were asymmetrically synthesized in high optical purity. In vitro assessment documented that both analogues are Sphk2 substrates, their phosphorylated species are potent S1P1 receptor agonists, and 3a-P is a potent S1P3 antagonist. After oral administration in mice, both compounds evoked lymphopenia, but their duration of action differed markedly. PMID:17994678

  19. Discovery of APD334: Design of a Clinical Stage Functional Antagonist of the Sphingosine-1-phosphate-1 Receptor

    PubMed Central

    2014-01-01

    APD334 was discovered as part of our internal effort to identify potent, centrally available, functional antagonists of the S1P1 receptor for use as next generation therapeutics for treating multiple sclerosis (MS) and other autoimmune diseases. APD334 is a potent functional antagonist of S1P1 and has a favorable PK/PD profile, producing robust lymphocyte lowering at relatively low plasma concentrations in several preclinical species. This new agent was efficacious in a mouse experimental autoimmune encephalomyelitis (EAE) model of MS and a rat collagen induced arthritis (CIA) model and was found to have appreciable central exposure. PMID:25516790

  20. Enhanced sphingosine-1-phosphate receptor 2 expression underlies female CNS autoimmunity susceptibility

    PubMed Central

    Cruz-Orengo, Lillian; Daniels, Brian P.; Dorsey, Denise; Basak, Sarah Alison; Grajales-Reyes, José G.; McCandless, Erin E.; Piccio, Laura; Schmidt, Robert E.; Cross, Anne H.; Crosby, Seth D.; Klein, Robyn S.

    2014-01-01

    Multiple sclerosis (MS) is an inflammatory disease of the CNS that is characterized by BBB dysfunction and has a much higher incidence in females. Compared with other strains of mice, EAE in the SJL mouse strain models multiple features of MS, including an enhanced sensitivity of female mice to disease; however, the molecular mechanisms that underlie the sex- and strain-dependent differences in disease susceptibility have not been described. We identified sphingosine-1-phosphate receptor 2 (S1PR2) as a sex- and strain-specific, disease-modifying molecule that regulates BBB permeability by destabilizing adherens junctions. S1PR2 expression was increased in disease-susceptible regions of the CNS of both female SJL EAE mice and female patients with MS compared with their male counterparts. Pharmacological blockade or lack of S1PR2 signaling decreased EAE disease severity as the result of enhanced endothelial barrier function. Enhanced S1PR2 signaling in an in vitro BBB model altered adherens junction formation via activation of Rho/ROCK, CDC42, and caveolin endocytosis-dependent pathways, resulting in loss of apicobasal polarity and relocation of abluminal CXCL12 to vessel lumina. Furthermore, S1PR2-dependent BBB disruption and CXCL12 relocation were observed in vivo. These results identify a link between S1PR2 signaling and BBB polarity and implicate S1PR2 in sex-specific patterns of disease during CNS autoimmunity. PMID:24812668

  1. Effects of sphingosine-1-phosphate receptor 1 phosphorylation in response to FTY720 during neuroinflammation

    PubMed Central

    Huang, Yingxiang; Garris, Christopher S.; Moreno, Monica A.; Griffin, Christina W.; Han, May H.

    2016-01-01

    Fingolimod (FTY720, Gilenya), a sphingosine-1-phosphate receptor (S1PR) modulator, is one of the first-line immunomodulatory therapies for treatment of relapsing-remitting multiple sclerosis (MS). Human S1PR1 variants have been reported to have functional heterogeneity in vitro, suggesting that S1PR1 function may influence FTY720 efficacy. In this study, we examined the influence of S1PR1 phosphorylation on response to FTY720 in neuroinflammation. We found that mice carrying a phosphorylation-defective S1pr1 gene [S1PR1(S5A) mice] were refractory to FTY720 treatment in MOG35-55-immunized and Th17-mediated experimental autoimmune encephalomyelitis (EAE) models. Long-term treatment with FTY720 induced significant lymphopenia and suppressed Th17 response in the peripheral immune system via downregulating STAT3 phosphorylation in both WT and S1PR1(S5A) mice. However, FTY720 did not effectively prevent neuroinflammation in the S1PR1(S5A) EAE mice as a result of encephalitogenic cells expressing C-C chemokine receptor 6 (CCR6). Combined treatment with FTY720 and anti-CCR6 delayed disease progression in S1PR1(S5A) EAE mice, suggesting that CCR6-mediated cell trafficking can overcome the effects of FTY720. This work may have translational relevance regarding FTY720 efficacy in MS patients and suggests that cell type–specific therapies may enhance therapeutic efficacy in MS. PMID:27699272

  2. Sphingosine-1-Phosphate Receptor 2 Regulates Proinflammatory Cytokine Production and Osteoclastogenesis

    PubMed Central

    2016-01-01

    Sphingosine-1-phosphate receptor 2 (S1PR2) couples with the Gi, Gq, and G12/13 group of proteins, which modulate an array of cellular signaling pathways and affect immune responses to multiple stimuli. In this study, we demonstrated that knockdown of S1PR2 by a specific S1PR2 shRNA lentiviral vector significantly inhibited IL-1β, IL-6, and TNF-α protein levels induced by oral pathogen Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) in murine bone marrow-derived monocytes and macrophages (BMMs) compared with controls. In addition, knockdown of S1PR2 by the S1PR2 shRNA lentiviral vector suppressed p-PI3K, p-ERK, p-JNK, p-p38, and p-NF-κBp65 protein expressions induced by A. actinomycetemcomitans. Furthermore, bone marrow cells treated with the S1PR2 shRNA lentiviral vector inhibited osteoclastogenesis induced by RANKL compared with controls. The S1PR2 shRNA suppressed the mRNA levels of six osteoclastogenic factors including nuclear factor of activated T-cells cytoplasmic calcineurin-dependent 1 (NFATc1), cathepsin K (Ctsk), acid phosphatase 5 (Acp5), osteoclast-associated receptor (Oscar), dendritic cells specific transmembrane protein (Dcstamp), and osteoclast stimulatory transmembrane protein (Ocstamp) in bone marrow cells. We conclude that S1PR2 plays an essential role in modulating proinflammatory cytokine production and osteoclastogenesis. Blocking S1PR2 signaling might be a novel therapeutic strategy to treat inflammatory bone loss diseases. PMID:27224249

  3. Differential Effects of Long Term FTY720 Treatment on Endothelial versus Smooth Muscle Cell Signaling to S1P in Rat Mesenteric Arteries

    PubMed Central

    Hamidi Shishavan, Mahdi; Bidadkosh, Arash; Yazdani, Saleh; Lambooy, Sebastiaan; van den Born, Jacob; Buikema, Hendrik; Henning, Robert H.; Deelman, Leo E.

    2016-01-01

    The sphingosine-1-phosphate (S1P) analog FTY720 exerts pleiotropic effects on the cardiovascular system and causes down-regulation of S1P receptors. Myogenic constriction is an important mechanism regulating resistance vessel function and is known to be modulated by S1P. Here we investigated myogenic constriction and vascular function of mesenteric arteries of rats chronically treated with FTY720. Wistar rats received FTY720 1mg/kg/daily for six weeks. At termination, blood pressure was recorded and small mesenteric arteries collected for vascular studies in a perfusion set up. Myogenic constriction to increased intraluminal pressure was low, but a sub-threshold dose of S1P profoundly augmented myogenic constriction in arteries of both controls and animals chronically treated with FTY720. Interestingly, endothelial denudation blocked the response to S1P in arteries of FTY720-treated animals, but not in control rats. In acute experiments, presence of FTY720 significantly augmented the contractile response to S1P, an effect that was partially abolished after the inhibition of cyclooxygenase (COX-)-derived prostaglandins. FTY720 down regulated S1P1 but not S1P2 in renal resistance arteries and in cultured human endothelial cells. This study therefore demonstrates the endothelium is able to compensate for the complete loss of responsiveness of the smooth muscle layer to S1P after long term FTY720 treatment through a mechanism that most likely involves enhanced production of contractile prostaglandins by the endothelium. PMID:27583547

  4. Activated platelets release sphingosine 1-phosphate and induce hypersensitivity to noxious heat stimuli in vivo

    PubMed Central

    Weth, Daniela; Benetti, Camilla; Rauch, Caroline; Gstraunthaler, Gerhard; Schmidt, Helmut; Geisslinger, Gerd; Sabbadini, Roger; Proia, Richard L.; Kress, Michaela

    2015-01-01

    At the site of injury activated platelets release various mediators, one of which is sphingosine 1-phosphate (S1P). It was the aim of this study to explore whether activated human platelets had a pronociceptive effect in an in vivo mouse model and whether this effect was based on the release of S1P and subsequent activation of neuronal S1P receptors 1 or 3. Human platelets were prepared in different concentrations (105/μl, 106/μl, 107/μl) and assessed in mice with different genetic backgrounds (WT, S1P1fl/fl, SNS-S1P1−/−, S1P3−/−). Intracutaneous injections of activated human platelets induced a significant, dose-dependent hypersensitivity to noxious thermal stimulation. The degree of heat hypersensitivity correlated with the platelet concentration as well as the platelet S1P content and the amount of S1P released upon platelet activation as measured with LC MS/MS. Despite the significant correlations between S1P and platelet count, no difference in paw withdrawal latency (PWL) was observed in mice with a global null mutation of the S1P3 receptor or a conditional deletion of the S1P1 receptor in nociceptive primary afferents. Furthermore, neutralization of S1P with a selective anti-S1P antibody did not abolish platelet induced heat hypersensitivity. Our results suggest that activated platelets release S1P and induce heat hypersensitivity in vivo. However, the platelet induced heat hypersensitivity was caused by mediators other than S1P. PMID:25954148

  5. Sphingosine-1-phosphate inhibits the adipogenic differentiation of 3T3-L1 preadipocytes.

    PubMed

    Moon, Myung-Hee; Jeong, Jae-Kyo; Lee, You-Jin; Seol, Jae-Won; Park, Sang-Youel

    2014-10-01

    Sphingosine-1-phosphate (S1P) is a pluripotent lipid mediator that transmits signals through G-protein-coupled receptors to control diverse biological processes. The novel biological activity of S1P in the adipogenesis of 3T3-L1 preadipocytes was identified in the present study. S1P significantly decreased lipid accumulation in maturing preadipocytes in a dose‑dependent manner. In order to understand the anti‑adipogenic effects of S1P, preadipocytes were treated with S1P, and the change in the expression of several adipogenic transcription factors and enzymes was investigated using quantitative RT-PCR. S1P downregulated the transcriptional levels of the peroxisome proliferator-activated receptor γ, CCAAT/enhancer binding proteins and adiponectin, which are markers of adipogenic differentiation. The effects of S1P on the levels of mitogen‑activated protein kinase (MAPK) signals in preadipocytes were also investigated. The activation of JNK and p38 were downregulated by S1P treatment in human preadipocytes. In conclusion, the results of this study suggest that S1P alters fat mass by directly affecting adipogenesis. This is mediated by the downregulation of adipogenic transcription factors and by inactivation of the JNK and p38 MAPK pathways. Thus, selective targeting of the S1P receptors and sphingosine kinases may have clinical applications for the treatment of obesity. PMID:25050633

  6. Expression of functional sphingosine-1 phosphate receptor-1 is reduced by B cell receptor signaling and increased by inhibition of PI3 kinase δ but not SYK or BTK in chronic lymphocytic leukemia cells.

    PubMed

    Till, Kathleen J; Pettitt, Andrew R; Slupsky, Joseph R

    2015-03-01

    BCR signaling pathway inhibitors such as ibrutinib, idelalisib, and fostamatinib (respective inhibitors of Bruton's tyrosine kinase, PI3Kδ, and spleen tyrosine kinase) represent a significant therapeutic advance in B cell malignancies, including chronic lymphocytic leukemia (CLL). These drugs are distinctive in increasing blood lymphocytes while simultaneously shrinking enlarged lymph nodes, suggesting anatomical redistribution of CLL cells from lymph nodes into the blood. However, the mechanisms underlying this phenomenon are incompletely understood. In this study, we showed that the egress receptor, sphingosine-1-phosphate (S1P) receptor 1 (S1PR1), was expressed at low levels in normal germinal centers and CLL lymph nodes in vivo but became upregulated on normal B cells and, to a variable and lesser extent, CLL cells following in vitro incubation in S1P-free medium. Spontaneous recovery of S1PR1 expression on normal B and CLL cells was prevented by BCR cross-linking, whereas treatment of CLL cells with idelalisib increased S1PR1 expression and migration toward S1P, the greatest increase occurring in cases with unmutated IgH V region genes. Intriguingly, ibrutinib and fostamatinib had no effect on S1PR1 expression or function. Conversely, chemokine-induced migration, which requires integrin activation and is essential for the entry of lymphocytes into lymph nodes as well as their retention, was blocked by ibrutinib and fostamatinib, but not idelalisib. In summary, our results suggest that different BCR signaling inhibitors redistribute CLL cells from lymph nodes into the blood through distinct mechanisms: idelalisib actively promotes egress by upregulating S1PR1, whereas fostamatinib and ibrutinib may reduce CLL cell entry and retention by suppressing chemokine-induced integrin activation.

  7. Electrophysiological and functional effects of sphingosine-1-phosphate in mouse ventricular fibroblasts

    SciTech Connect

    Benamer, Najate; Bois, Patrick

    2011-04-29

    Highlights: {yields} In cardiac fibroblasts, SUR2/Kir6.1 channel is activated by S1P via the S1P3R. {yields} S1P increases cell proliferation through SUR2/Kir6.1 activation. {yields} S1P decreases collagen and IL-6 secretion through SUR2/Kir6.1 activation. {yields} S1P stimulates fibroblast migration independently from SUR2/Kir6.1 channel. -- Abstract: The aim of this study was to characterize the effects of sphingosine-1-phosphate (S1P) on cardiac ventricular fibroblasts. Impacts of S1P on fibroblast excitability, cell migration, proliferation and secretion were characterized. The patch-clamp technique in the whole-cell configuration was used to study the S1P-induced current from mouse ventricular fibroblasts. The expression level of the S1P receptor during cell culture duration was evaluated by western-blot. Fibroblast proliferation and migration were quantified using the methylene blue assay and the Boyden chamber technique, respectively. Finally, fibroblast secretion properties were estimated by quantification of the IL-6 and collagen levels using ELISA and SIRCOL collagen assays, respectively. We found that S1P activated SUR2/Kir6.1 channel and that this effect was sensitive to specific inhibition of the S1P receptor of type 3 (S1P3R). In contrast, S1P1R receptor inhibition had no effect. Moreover, the S1P-induced current increased with cell culture duration whereas S1P3R expression level remained constant. The activation of SUR2/Kir6.1 channel by S1P via S1P3R stimulated cell proliferation and decreased IL-6 and collagen secretions. S1P also stimulated fibroblast migration via S1P3R but independently from SUR2/Kir6.1 channel activation. This study demonstrates that S1P, via S1P3R, affects cardiac ventricular fibroblasts function independently or through activation of SUR2/Kir6.1 channel. The latter effect occurs after fibroblasts differentiate into myofibroblasts, opening a new potential therapeutic strategy to modulate fibrosis after cardiac

  8. DEVELOPMENT OF A METHOD FOR QUANTITATING SPHINGOID BASE 1-PHOSPHATES IN BLOOD SPOTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Red blood cells (RBC) accumulate, store and release sphingoid base 1-phosphates,important ligands for the extracellular receptors S1P1-5. The ability of RBC to accumulate these bioactive lipids is because, with the exception of sphingosine kinase, the enzymes responsible for metabolizing sphingosine...

  9. Aberrant expression of the S1P regulating enzymes, SPHK1 and SGPL1, contributes to a migratory phenotype in OSCC mediated through S1PR2

    PubMed Central

    Patmanathan, Sathya Narayanan; Johnson, Steven P.; Lai, Sook Ling; Panja Bernam, Suthashini; Lopes, Victor; Wei, Wenbin; Ibrahim, Maha Hafez; Torta, Federico; Narayanaswamy, Pradeep; Wenk, Markus R.; Herr, Deron R.; Murray, Paul G.; Yap, Lee Fah; Paterson, Ian C.

    2016-01-01

    Oral squamous cell carcinoma (OSCC) is a lethal disease with a 5-year mortality rate of around 50%. Molecular targeted therapies are not in routine use and novel therapeutic targets are required. Our previous microarray data indicated sphingosine 1-phosphate (S1P) metabolism and signalling was deregulated in OSCC. In this study, we have investigated the contribution of S1P signalling to the pathogenesis of OSCC. We show that the expression of the two major enzymes that regulate S1P levels were altered in OSCC: SPHK1 was significantly upregulated in OSCC tissues compared to normal oral mucosa and low levels of SGPL1 mRNA correlated with a worse overall survival. In in vitro studies, S1P enhanced the migration/invasion of OSCC cells and attenuated cisplatin-induced death. We also demonstrate that S1P receptor expression is deregulated in primary OSCCs and that S1PR2 is over-expressed in a subset of tumours, which in part mediates S1P-induced migration of OSCC cells. Lastly, we demonstrate that FTY720 induced significantly more apoptosis in OSCC cells compared to non-malignant cells and that FTY720 acted synergistically with cisplatin to induce cell death. Taken together, our data show that S1P signalling promotes tumour aggressiveness in OSCC and identify S1P signalling as a potential therapeutic target. PMID:27160553

  10. Functional variants of sphingosine-1-phosphate receptor 1 gene associate with asthma susceptibility

    PubMed Central

    Sun, Xiaoguang; Ma, Shwu-Fan; Wade, Michael S.; Flores, Carlos; Pino-Yanes, Maria; Moitra, Jaideep; Ober, Carole; Kittles, Rick; Husain, Aliya N.; Ford, Jean G.; Garcia, Joe G. N.

    2012-01-01

    Background The genetic mechanisms underlying asthma remain unclear. Increased permeability of the microvasculature is a feature of asthma and the sphingosine-1-phosphate receptor, S1PR1, is an essential participant regulating lung vascular integrity and responses to lung inflammation. Objective We explored the contribution of polymorphisms in the S1PR1 gene (S1PR1) to asthma susceptibility. Methods A combination of gene re-sequencing for SNP discovery, case-control association, functional evaluation of associated SNPs, and protein immunochemistry studies was utilized. Results Immunohistochemistry studies demonstrated significantly decreased S1PR1 protein expression in pulmonary vessels in asthmatic lungs compared to non-asthmatic individuals (p<0.05). Direct DNA sequencing of 27 multiethnic samples identified 39 S1PR1 variants (18 novel SNPs). Association studies were performed based on genotyping results from cosmopolitan tagging SNPs in three case-control cohorts from Chicago and New York totaling 1061 subjects (502 cases and 559 controls). Promoter SNP rs2038366 (−1557G/T) was found to be associated with asthma (p=0.03) in European Americans. In African Americans, an association was found for both asthma and severe asthma for intronic SNP rs3753194 (c.−164+170A/G) (p=0.006 and p=0.040, respectively) and for promoter SNP rs59317557 (−532C/G) with severe asthma (p=0.028). Consistent with predicted in silico functionality, alleles of promoter SNPs rs2038366 (−1557G/T) and rs59317557 (−532C/G) influenced the activity of a luciferase S1PR1 reporter vector in transfected endothelial cells exposed to growth factors (EGF, PDGF, VEGF) known to be increased in asthmatic airways. Conclusion These data provide strong support for a role for S1PR1 gene variants in asthma susceptibility and severity. Clinical Implications Our results indicate S1PR1 is a novel asthma candidate gene and an attractive target for future therapeutic strategies. Capsule summary This study

  11. ER stress stimulates production of the key antimicrobial peptide, cathelicidin, by forming a previously unidentified intracellular S1P signaling complex

    PubMed Central

    Park, Kyungho; Ikushiro, Hiroko; Shin, Kyong-Oh; Kim, Young il; Kim, Jong Youl; Lee, Yong-Moon; Yano, Takato; Holleran, Walter M.; Elias, Peter; Uchida, Yoshikazu

    2016-01-01

    We recently identified a previously unidentified sphingosine-1-phosphate (S1P) signaling mechanism that stimulates production of a key innate immune element, cathelicidin antimicrobial peptide (CAMP), in mammalian cells exposed to external perturbations, such as UVB irradiation and other oxidative stressors that provoke subapoptotic levels of endoplasmic reticulum (ER) stress, independent of the well-known vitamin D receptor-dependent mechanism. ER stress increases cellular ceramide and one of its distal metabolites, S1P, which activates NF-κB followed by C/EBPα activation, leading to CAMP production, but in a S1P receptor-independent fashion. We now show that S1P activates NF-κB through formation of a previously unidentified signaling complex, consisting of S1P, TRAF2, and RIP1 that further associates with three stress-responsive proteins; i.e., heat shock proteins (GRP94 and HSP90α) and IRE1α. S1P specifically interacts with the N-terminal domain of heat shock proteins. Because this ER stress-initiated mechanism is operative in both epithelial cells and macrophages, it appears to be a universal, highly conserved response, broadly protective against diverse external perturbations that lead to increased ER stress. Finally, these studies further illuminate how ER stress and S1P orchestrate critical stress-specific signals that regulate production of one protective response by stimulating production of the key innate immune element, CAMP. PMID:26903652

  12. Sphingosine 1-phosphate receptor 2 antagonist JTE-013 increases the excitability of sensory neurons independently of the receptor

    PubMed Central

    Li, Chao; Chi, Xian Xuan; Xie, Wenrui; Strong, J. A.; Zhang, J.-M.

    2012-01-01

    Previously we demonstrated that sphingosine 1-phosphate receptor 1 (S1PR1) played a prominent, but not exclusive, role in enhancing the excitability of small-diameter sensory neurons, suggesting that other S1PRs can modulate neuronal excitability. To examine the potential role of S1PR2 in regulating neuronal excitability we used the established selective antagonist of S1PR2, JTE-013. Here we report that exposure to JTE-013 alone produced a significant increase in excitability in a time- and concentration-dependent manner in 70–80% of recorded neurons. Internal perfusion of sensory neurons with guanosine 5′-O-(2-thiodiphosphate) (GDP-β-S) via the recording pipette inhibited the sensitization produced by JTE-013 as well as prostaglandin E2. Pretreatment with pertussis toxin or the selective S1PR1 antagonist W146 blocked the sensitization produced by JTE-013. These results indicate that JTE-013 might act as an agonist at other G protein-coupled receptors. In neurons that were sensitized by JTE-013, single-cell RT-PCR studies demonstrated that these neurons did not express the mRNA for S1PR2. In behavioral studies, injection of JTE-013 into the rat's hindpaw produced a significant increase in the mechanical sensitivity in the ipsilateral, but not contralateral, paw. Injection of JTE-013 did not affect the withdrawal latency to thermal stimulation. Thus JTE-013 augments neuronal excitability independently of S1PR2 by unknown mechanisms that may involve activation of other G protein-coupled receptors such as S1PR1. Clearly, further studies are warranted to establish the causal nature of this increased sensitivity, and future studies of neuronal function using JTE-013 should be interpreted with caution. PMID:22673325

  13. S1P-Yap1 signaling regulates endoderm formation required for cardiac precursor cell migration in zebrafish.

    PubMed

    Fukui, Hajime; Terai, Kenta; Nakajima, Hiroyuki; Chiba, Ayano; Fukuhara, Shigetomo; Mochizuki, Naoki

    2014-10-13

    To form the primary heart tube in zebrafish, bilateral cardiac precursor cells (CPCs) migrate toward the midline beneath the endoderm. Mutants lacking endoderm and fish with defective sphingosine 1-phosphate (S1P) signaling exhibit cardia bifida. Endoderm defects lead to the lack of foothold for the CPCs, whereas the cause of cardia bifida in S1P signaling mutants remains unclear. Here we show that S1P signaling regulates CPC migration through Yes-associated protein 1 (Yap1)-dependent endoderm survival. Cardia bifida seen in spns2 (S1P transporter) morphants and s1pr2 (S1P receptor-2) morphants could be rescued by endodermal expression of nuclear localized form of yap1. yap1 morphants had decreased expression of the Yap1/Tead target connective tissue growth factor a (Ctgfa) and consequently increased endodermal cell apoptosis. Consistently, ctgfa morphants showed defects of the endodermal sheet and cardia bifida. Collectively, we show that S1pr2/Yap1-regulated ctgfa expression is essential for the proper endoderm formation required for CPC migration.

  14. Sphingosine-1-Phosphate Receptor-1 Selective Agonist Enhances Collateral Growth and Protects against Subsequent Stroke

    PubMed Central

    Ichijo, Masahiko; Ishibashi, Satoru; Li, Fuying; Yui, Daishi; Miki, Kazunori; Mizusawa, Hidehiro; Yokota, Takanori

    2015-01-01

    Background and Purpose Collateral growth after acute occlusion of an intracranial artery is triggered by increasing shear stress in preexisting collateral pathways. Recently, sphingosine-1-phosphate receptor-1 (S1PR1) on endothelial cells was reported to be essential in sensing fluid shear stress. Here, we evaluated the expression of S1PR1 in the hypoperfused mouse brain and investigated the effect of a selective S1PR1 agonist on leptomeningeal collateral growth and subsequent ischemic damage after focal ischemia. Methods In C57Bl/6 mice (n = 133) subjected to unilateral common carotid occlusion (CCAO) and sham surgery. The first series examined the time course of collateral growth, cell proliferation, and S1PR1 expression in the leptomeningeal arteries after CCAO. The second series examined the relationship between pharmacological regulation of S1PR1 and collateral growth of leptomeningeal anastomoses. Animals were randomly assigned to one of the following groups: LtCCAO and daily intraperitoneal (ip) injection for 7 days of an S1PR1 selective agonist (SEW2871, 5 mg/kg/day); sham surgery and daily ip injection for 7 days of SEW2871 after surgery; LtCCAO and daily ip injection for 7 days of SEW2871 and an S1PR1 inverse agonist (VPC23019, 0.5 mg/kg); LtCCAO and daily ip injection of DMSO for 7 days after surgery; and sham surgery and daily ip injection of DMSO for 7 days. Leptomeningeal anastomoses were visualized 14 days after LtCCAO by latex perfusion method, and a set of animals underwent subsequent permanent middle cerebral artery occlusion (pMCAO) 7days after the treatment termination. Neurological functions 1hour, 1, 4, and 7days and infarction volume 7days after pMCAO were evaluated. Results In parallel with the increase in S1PR1 mRNA levels, S1PR1 expression colocalized with endothelial cell markers in the leptomeningeal arteries, increased markedly on the side of the CCAO, and peaked 7 days after CCAO. Mitotic cell numbers in the leptomeningeal arteries

  15. Chemical Hypoxia Brings to Light Altered Autocrine Sphingosine-1-Phosphate Signalling in Rheumatoid Arthritis Synovial Fibroblasts

    PubMed Central

    Zhao, Chenqi; Moreno-Nieves, Uriel; Di Battista, John A.; Fernandes, Maria J.; Touaibia, Mohamed; Bourgoin, Sylvain G.

    2015-01-01

    Emerging evidence suggests a role for sphingosine-1-phosphate (S1P) in various aspects of rheumatoid arthritis (RA) pathogenesis. In this study we compared the effect of chemical hypoxia induced by cobalt chloride (CoCl2) on the expression of S1P metabolic enzymes and cytokine/chemokine secretion in normal fibroblast-like synoviocytes (FLS) and RAFLS. RAFLS incubated with CoCl2, but not S1P, produced less IL-8 and MCP-1 than normal FLS. Furthermore, incubation with the S1P2 and S1P3 receptor antagonists, JTE-013 and CAY10444, reduced CoCl2-mediated chemokine production in normal FLS but not in RAFLS. RAFLS showed lower levels of intracellular S1P and enhanced mRNA expression of S1P phosphatase 1 (SGPP1) and S1P lyase (SPL), the enzymes that are involved in intracellular S1P degradation, when compared to normal FLS. Incubation with CoCl2 decreased SGPP1 mRNA and protein and SPL mRNA as well. Inhibition of SPL enhanced CoCl2-mediated cytokine/chemokine release and restored autocrine activation of S1P2 and S1P3 receptors in RAFLS. The results suggest that the sphingolipid pathway regulating the intracellular levels of S1P is dysregulated in RAFLS and has a significant impact on cell autocrine activation by S1P. Altered sphingolipid metabolism in FLS from patients with advanced RA raises the issue of synovial cell burnout due to chronic inflammation. PMID:26556954

  16. S1P3-mediated cardiac fibrosis in sphingosine kinase 1 transgenic mice involves reactive oxygen species

    PubMed Central

    Takuwa, Noriko; Ohkura, Sei-Ichiro; Takashima, Shin-Ichiro; Ohtani, Keisuke; Okamoto, Yasuo; Tanaka, Tamotsu; Hirano, Kaoru; Usui, Soichiro; Wang, Fei; Du, Wa; Yoshioka, Kazuaki; Banno, Yoshiko; Sasaki, Motoko; Ichi, Ikuyo; Okamura, Miwa; Sugimoto, Naotoshi; Mizugishi, Kiyomi; Nakanuma, Yasuni; Ishii, Isao; Takamura, Masayuki; Kaneko, Shuichi; Kojo, Shosuke; Satouchi, Kiyoshi; Mitumori, Kunitoshi; Chun, Jerold; Takuwa, Yoh

    2010-01-01

    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. PMID:19755413

  17. Sphingosine 1-phosphate-mediated α1B-adrenoceptor desensitization and phosphorylation. Direct and paracrine/autocrine actions

    PubMed Central

    Castillo-Badillo, Jean A.; Molina-Muñoz, Tzindilú; Romero-Ávila, M. Teresa; Vázquez-Macías, Aleida; Rivera, Richard; Chun, Jerold; García-Sáinz, J. Adolfo

    2012-01-01

    Sphingosine-1-phosphate-induced α1B-adrenergic receptor desensitization and phosphorylation was studied in rat-1 fibroblasts stably expressing enhanced green fluorescent protein-tagged adrenoceptors. Sphingosine-1-phosphate induced adrenoceptor desensitization and phosphorylation through a signaling cascade that involved phosphoinositide 3-kinase and protein kinase C activities. The autocrine/paracrine role of sphingosine-1-phosphate was also studied. It was observed that activation of receptor tyrosine kinases, such as insulin growth factor-1 (IGF-I) and epidermal growth factor (EGF) receptors increased sphingosine kinase activity. Such activation and consequent production of sphingosine-1-phosphate appears to be functionally relevant in IGF-I- and EGF-induced α1B-adrenoceptor phosphorylation and desensitization as evidenced by the following facts: a) expression of a catalytically inactive (dominant-negative) mutant of sphingosine kinase 1 or b) S1P1 receptor knockdown markedly reduced this growth factor action. This action of sphingosine-1-phosphate involves EGF receptor transactivation. In addition, taking advantage of the presence of the eGFP tag in the receptor construction, we showed that S1P was capable of inducing α1B-adrenergic receptor internalization and that its autocrine/paracrine generation was relevant for internalization induced by IGF-I. Four distinct hormone receptors and two autocrine/paracrine mediators participate in IGF-I receptor- α1B-adrenergic receptor crosstalk. PMID:22019450

  18. Apolipoprotein M modulates erythrocyte efflux and tubular reabsorption of sphingosine-1-phosphate

    PubMed Central

    Sutter, Iryna; Park, Rebekka; Othman, Alaa; Rohrer, Lucia; Hornemann, Thorsten; Stoffel, Markus; Devuyst, Olivier; von Eckardstein, Arnold

    2014-01-01

    Sphingosine-1-phosphate (S1P) mediates several cytoprotective functions of HDL. apoM acts as a S1P binding protein in HDL. Erythrocytes are the major source of S1P in plasma. After glomerular filtration, apoM is endocytosed in the proximal renal tubules. Human or murine HDL elicited time- and dose-dependent S1P efflux from erythrocytes. Compared with HDL of wild-type (wt) mice, S1P efflux was enhanced in the presence of HDL from apoM transgenic mice, but not diminished in the presence of HDL from apoM knockout (Apom−/−) mice. Artificially reconstituted and apoM-free HDL also effectively induced S1P efflux from erythrocytes. S1P and apoM were not measurable in the urine of wt mice. Apom−/− mice excreted significant amounts of S1P. apoM was detected in the urine of mice with defective tubular endocytosis because of knockout of the LDL receptor-related protein, chloride-proton exchanger ClC-5 (Clcn5−/−), or the cysteine transporter cystinosin. Urinary levels of S1P were significantly elevated in Clcn5−/− mice. In contrast to Apom−/− mice, these mice showed normal plasma concentrations for apoM and S1P. In conclusion, HDL facilitates S1P efflux from erythrocytes by both apoM-dependent and apoM-independent mechanisms. Moreover, apoM facilitates tubular reabsorption of S1P from the urine, however, with no impact on S1P plasma concentrations. PMID:24950692

  19. Tissue Distribution Dynamics of Human NK Cells Inferred from Peripheral Blood Depletion Kinetics after Sphingosine-1-Phosphate Receptor Blockade.

    PubMed

    Mehling, M; Burgener, A-V; Brinkmann, V; Bantug, G R; Dimeloe, S; Hoenger, G; Kappos, L; Hess, C

    2015-11-01

    Human natural killer (NK) cell subsets differentially distribute throughout the organism. While CD56(dim) and CD56(bright) NK cell subsets similarly reside in the bone marrow (BM), the CD56(dim) population predominantly accumulates in non-lymphoid tissues and the CD56(bright) counterpart in lymphoid tissue (LT). The dynamics with which these NK cell subsets redistribute to tissues remains unexplored. Here, we studied individuals newly exposed to fingolimod, a drug that efficiently blocks sphingosine-1-phosphate (S1P)-directed lymphocyte - including NK cell - egress from tissue to blood. During an observation period of 6h peripheral blood depletion of CD56(bright) NK cells was observed 3 h after first dose of fingolimod, with 40-50% depletion after 6 h, while a decrease of the numbers of CD56(dim) NK cells did not reach the level of statistical significance. In vitro, CD56(bright) and CD56(dim) NK cells responded comparably to the BM-homing chemokine CXCL12, while CD56(bright) NK cells migrated more efficiently in gradients of the LT-homing chemokines CCL19 and CCL21. In conjuncture with these in vitro studies, the indirectly observed subset-specific depletion kinetics from blood are compatible with preferential and more rapid redistribution of CD56(bright) NK cells from blood to peripheral tissue such as LT and possibly also the inflamed central nervous system. These data shed light on an unexplored level at which access of NK cells to LT, and thus, for example antigen-presenting cells, is regulated.

  20. Death and taxis: what non-mammalian models tell us about sphingosine-1-phosphate.

    PubMed

    Oskouian, Babak; Saba, Julie D

    2004-10-01

    Sphingosine-1-phosphate (S1P) is a signaling molecule that regulates critical events including mammalian cell proliferation, survival, migration and cell-cell interactions. Most of these signals are triggered by engagement of sphingosine-1-phosphate receptors of the Edg family. However, accumulating evidence derived from investigation of non-mammalian models that lack Edg receptors suggests that sphingosine-1-phosphate-like molecules can act through alternative mechanisms and thereby contribute to morphogenesis, development, reproduction and survival. This review provides an overview of sphingosine-1-phosphate metabolism, the isolation of genes in this pathway employing yeast genetics, the evidence for its influence on non-mammalian development, and the pertinence of these findings to human disease.

  1. FTY720 Protects Cardiac Microvessels of Diabetes: A Critical Role of S1P1/3 in Diabetic Heart Disease

    PubMed Central

    Wei, Liping; Gao, Haokao; Zhang, Rongqing; Tao, Ling; Cao, Feng; Wang, Haichang

    2012-01-01

    Background: Diabetes is associated with an increased risk of cardiac microvascular disease. The mechanisms by which this damage occurs are unknown. However, research suggests that signaling through the sphingosine-1-phosphates receptor 1 and 3 (S1P1/3) by FTY720, a sphiongolipid drug that is structually similar to SIP, may play a role in the treatment on cardiac microvascular dysfunction in diabetes. We hypothesized that FTY720 might exert the cardioprotective effects of S1P1 and S1P3 viaprotein kinase C-beta (PKCβ II) signaling pathway. Methodology/Principal Findings: Transthoracic echocardiography was performed to detect the change of cardiac function. Scanning and transmission electron microscope with lanthanum tracer were used to determine microvascular ultrastructure and permeability in vivo. Apoptosis was detected by TUNEL and CD31 dual labeling in paraffin-embedded sections. Laser capture miscrodissection was used to assess cardiac micovascular endothelial cells (CMECs) in vivo. RT-PCR and Western blot analysis were used to determine the mRNA levels and protein expression of S1P1, S1P3, and PKCβ II. In the diabetic rats vs. controls, cardiac capillaries showed significantly higher density; CD31 positive endothelial cells were significantly reduced; the apoptosis index of cardiac endothlial cells was significantly higher. And FTY720 could increase the expressional level of S1P1 and boost S1P3 trasnslocation from membrane to nuclear, then ameliorate cardiac microvascular barrier impairment and pathologic angiogenesis induced by diabetes. In addition, overexpression of PKCβ II significantly decreased the protective effect of FTY720. Conclusions: Our study represents that the deregulation of S1P1 and S1P3 is an important signalresponsible for cardiac microvascular dysfunction in diabetes. FTY720 might be competent to serve as a potential therapeutic approach for diabetic heart disease through ameliorating cardiac microvascular barrier impairment and

  2. AKP-11 - A Novel S1P1 Agonist with Favorable Safety Profile Attenuates Experimental Autoimmune Encephalomyelitis in Rat Model of Multiple Sclerosis

    PubMed Central

    Samuvel, Devadoss J.; Saxena, Nishant; Dhindsa, Jasdeep S.; Singh, Avtar K.; Gill, Gurmit S.; Grobelny, Damian W.; Singh, Inderjit

    2015-01-01

    Sphingosine-1-phosphate receptor 1 (S1P1) mediated regulation of lymphocyte egress from lymphoid organs is recognized as the mechanism of FTY720 (Fingolimod, Gilenya) efficacy in relapsing-remitting forms of multiple sclerosis (RRMS). In this study we describe a novel S1P1 agonist AKP-11, next generation of S1P1 agonist, with immunomodulatory activities in cell culture model and for therapeutic efficacy against an animal model of MS, i.e. experimental autoimmune encephalomyelitis (EAE) but without the adverse effects observed with FTY720. Like FTY720, AKP-11 bound to S1P1 is internalized and activates intracellular AKT and ERKs cellular signaling pathways. In contrast to FTY720, AKP-11 mediated S1P1 downregulation is independent of sphingosine kinase activity indicating it to be a direct agonist of S1P1. The S1P1 loss and inhibition of lymphocyte egress by FTY720 leads to lymphopenia. In comparison with FTY720, oral administration of AKP-11 caused milder and reversible lymphopenia while providing a similar degree of therapeutic efficacy in the EAE animal model. Consistent with the observed reversible lymphopenia with AKP-11, the S1P1 recycled back to cell membrane in AKP-11 treated cells following its withdrawal, but not with withdrawal of FTY720. Accordingly, a smaller degree of ubiquitination and proteolysis of S1P1 was observed in AKP-11 treated cells as compared to FTY720. Consistent with previous observations, FTY720 treatment is associated with adverse effects of bradycardia and lung vascular leaks in rodents, whereas AKP-11 treatment had undetectable effects on bradycardia and reduced lung vascular leaks as compared to FTY720. Taken together, the data documents that AKP-11 treatment cause milder and reversible lymphopenia with milder adverse effects while maintaining therapeutic efficacy similar to that observed with FTY720, thus indicating therapeutic potential of AKP-11 for treatment of MS and related autoimmune disorders. PMID:26513477

  3. B Lymphocytes Exit Lymph Nodes through Cortical Lymphatic Sinusoids Near to Lymph Node Follicles by a Mechanism Independent of S1P-Mediated Chemotaxis

    PubMed Central

    Sinha, Rajesh K.; Park, Chung; Hwang, Il-Young; Davis, Michael D.; Kehrl, John H.

    2009-01-01

    Sphingosine-1 Phosphate (S1P) helps mediate lymphocyte egress from lymph nodes, yet significant mechanistic questions remain. Here we show that B lymphocyte egress sites exist close to lymph node follicles. Recent B cell emigrants localize towards follicle centers, while longer-term residents tend towards cortical sinusoids. Exiting B lymphocytes squeeze through apparent portals in the lymphatic endothelium. Treatment with the S1P receptor agonist FTY720 empties the cortical sinusoids of lymphocytes, blocks lymphatic endothelial penetration, and displaces B lymphocytes into the T cell zone. S1P3−/− B cells, which lack chemoattractant responses to S1P, transit lymph nodes normally, while Gnai2−/− B cells, which have impaired responses to chemokines and S1P, transit more rapidly than do wild type cells. This study identifies a major site of B lymphocyte lymph node egress, shows that FTY720 treatment blocks passage through the cortical lymphatic endothelium, and argues against a functional role for S1P chemotaxis in B lymphocyte egress. PMID:19230723

  4. Targeted Proteomics-Driven Computational Modeling of Macrophage S1P Chemosensing.

    PubMed

    Manes, Nathan P; Angermann, Bastian R; Koppenol-Raab, Marijke; An, Eunkyung; Sjoelund, Virginie H; Sun, Jing; Ishii, Masaru; Germain, Ronald N; Meier-Schellersheim, Martin; Nita-Lazar, Aleksandra

    2015-10-01

    Osteoclasts are monocyte-derived multinuclear cells that directly attach to and resorb bone. Sphingosine-1-phosphate (S1P)(1) regulates bone resorption by functioning as both a chemoattractant and chemorepellent of osteoclast precursors through two G-protein coupled receptors that antagonize each other in an S1P-concentration-dependent manner. To quantitatively explore the behavior of this chemosensing pathway, we applied targeted proteomics, transcriptomics, and rule-based pathway modeling using the Simmune toolset. RAW264.7 cells (a mouse monocyte/macrophage cell line) were used as model osteoclast precursors, RNA-seq was used to identify expressed target proteins, and selected reaction monitoring (SRM) mass spectrometry using internal peptide standards was used to perform absolute abundance measurements of pathway proteins. The resulting transcript and protein abundance values were strongly correlated. Measured protein abundance values, used as simulation input parameters, led to in silico pathway behavior matching in vitro measurements. Moreover, once model parameters were established, even simulated responses toward stimuli that were not used for parameterization were consistent with experimental findings. These findings demonstrate the feasibility and value of combining targeted mass spectrometry with pathway modeling for advancing biological insight.

  5. Targeted Proteomics-Driven Computational Modeling of Macrophage S1P Chemosensing*

    PubMed Central

    Manes, Nathan P.; Angermann, Bastian R.; Koppenol-Raab, Marijke; An, Eunkyung; Sjoelund, Virginie H.; Sun, Jing; Ishii, Masaru; Germain, Ronald N.; Meier-Schellersheim, Martin; Nita-Lazar, Aleksandra

    2015-01-01

    Osteoclasts are monocyte-derived multinuclear cells that directly attach to and resorb bone. Sphingosine-1-phosphate (S1P)1 regulates bone resorption by functioning as both a chemoattractant and chemorepellent of osteoclast precursors through two G-protein coupled receptors that antagonize each other in an S1P-concentration-dependent manner. To quantitatively explore the behavior of this chemosensing pathway, we applied targeted proteomics, transcriptomics, and rule-based pathway modeling using the Simmune toolset. RAW264.7 cells (a mouse monocyte/macrophage cell line) were used as model osteoclast precursors, RNA-seq was used to identify expressed target proteins, and selected reaction monitoring (SRM) mass spectrometry using internal peptide standards was used to perform absolute abundance measurements of pathway proteins. The resulting transcript and protein abundance values were strongly correlated. Measured protein abundance values, used as simulation input parameters, led to in silico pathway behavior matching in vitro measurements. Moreover, once model parameters were established, even simulated responses toward stimuli that were not used for parameterization were consistent with experimental findings. These findings demonstrate the feasibility and value of combining targeted mass spectrometry with pathway modeling for advancing biological insight. PMID:26199343

  6. Targeted Proteomics-Driven Computational Modeling of Macrophage S1P Chemosensing.

    PubMed

    Manes, Nathan P; Angermann, Bastian R; Koppenol-Raab, Marijke; An, Eunkyung; Sjoelund, Virginie H; Sun, Jing; Ishii, Masaru; Germain, Ronald N; Meier-Schellersheim, Martin; Nita-Lazar, Aleksandra

    2015-10-01

    Osteoclasts are monocyte-derived multinuclear cells that directly attach to and resorb bone. Sphingosine-1-phosphate (S1P)(1) regulates bone resorption by functioning as both a chemoattractant and chemorepellent of osteoclast precursors through two G-protein coupled receptors that antagonize each other in an S1P-concentration-dependent manner. To quantitatively explore the behavior of this chemosensing pathway, we applied targeted proteomics, transcriptomics, and rule-based pathway modeling using the Simmune toolset. RAW264.7 cells (a mouse monocyte/macrophage cell line) were used as model osteoclast precursors, RNA-seq was used to identify expressed target proteins, and selected reaction monitoring (SRM) mass spectrometry using internal peptide standards was used to perform absolute abundance measurements of pathway proteins. The resulting transcript and protein abundance values were strongly correlated. Measured protein abundance values, used as simulation input parameters, led to in silico pathway behavior matching in vitro measurements. Moreover, once model parameters were established, even simulated responses toward stimuli that were not used for parameterization were consistent with experimental findings. These findings demonstrate the feasibility and value of combining targeted mass spectrometry with pathway modeling for advancing biological insight. PMID:26199343

  7. Sphingosine-1-phosphate protects endothelial glycocalyx by inhibiting syndecan-1 shedding.

    PubMed

    Zeng, Ye; Adamson, Roger H; Curry, Fitz-Roy E; Tarbell, John M

    2014-02-01

    Endothelial cells (ECs) are covered by a surface glycocalyx layer that forms part of the barrier and mechanosensing functions of the blood-tissue interface. Removal of albumin in bathing media induces collapse or shedding of the glycocalyx. The electrostatic interaction between arginine residues on albumin, and negatively charged glycosaminoglycans (GAGs) in the glycocalyx have been hypothesized to stabilize the glycocalyx structure. Because albumin is one of the primary carriers of the phospholipid sphingosine-1-phosphate (S1P), we evaluated the alternate hypothesis that S1P, acting via S1P1 receptors, plays the primary role in stabilizing the endothelial glycocalyx. Using confocal microscopy on rat fat-pad ECs, we demonstrated that heparan sulfate (HS), chondroitin sulfate (CS), and ectodomain of syndecan-1 were shed from the endothelial cell surface after removal of plasma protein but were retained in the presence of S1P at concentrations of >100 nM. S1P1 receptor antagonism abolished the protection of the glycocalyx by S1P and plasma proteins. S1P reduced GAGs released after removal of plasma protein. The mechanism of protection from loss of glycocalyx components by S1P-dependent pathways was shown to be suppression of metalloproteinase (MMP) activity. General inhibition of MMPs protected against loss of CS and syndecan-1. Specific inhibition of MMP-9 and MMP-13 protected against CS loss. We conclude that S1P plays a critical role in protecting the glycocalyx via S1P1 and inhibits the protease activity-dependent shedding of CS, HS, and the syndecan-1 ectodomain. Our results provide new insight into the role for S1P in protecting the glycocalyx and maintaining vascular homeostasis.

  8. Identification of benzoxazole analogs as novel, S1P(3) sparing S1P(1) agonists.

    PubMed

    Deng, Guanghui; Meng, Qinghua; Liu, Qian; Xu, Xuesong; Xu, Qiongfeng; Ren, Feng; Guo, Taylor B; Lu, Hongtao; Xiang, Jia-Ning; Elliott, John D; Lin, Xichen

    2012-06-15

    A novel series of benzoxazole-derived S1P(1) agonists were designed based on scaffold hopping molecular design strategy combined with computational approaches. Extensive SAR studies led to the discovery of compound 17d as a selective S1P(1) agonist (over S1P(3)) with high CNS penetration and favorable DMPK properties. 17d also demonstrated in vivo pharmacological efficacy to reduce blood lymphocyte in mice after oral administration.

  9. Sphingosine-1-Phosphate Signaling in Immune Cells and Inflammation: Roles and Therapeutic Potential

    PubMed Central

    Aoki, Masayo; Aoki, Hiroaki; Ramanathan, Rajesh; Hait, Nitai C.; Takabe, Kazuaki

    2016-01-01

    Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid metabolite involved in many critical cell processes. It is produced by the phosphorylation of sphingosine by sphingosine kinases (SphKs) and exported out of cells via transporters such as spinster homolog 2 (Spns2). S1P regulates diverse physiological processes by binding to specific G protein-binding receptors, S1P receptors (S1PRs) 1–5, through a process coined as “inside-out signaling.” The S1P concentration gradient between various tissues promotes S1PR1-dependent migration of T cells from secondary lymphoid organs into the lymphatic and blood circulation. S1P suppresses T cell egress from and promotes retention in inflamed peripheral tissues. S1PR1 in T and B cells as well as Spns2 in endothelial cells contributes to lymphocyte trafficking. FTY720 (Fingolimod) is a functional antagonist of S1PRs that induces systemic lymphopenia by suppression of lymphocyte egress from lymphoid organs. In this review, we summarize previous findings and new discoveries about the importance of S1P and S1PR signaling in the recruitment of immune cells and lymphocyte retention in inflamed tissues. We also discuss the role of S1P-S1PR1 axis in inflammatory diseases and wound healing. PMID:26966342

  10. Sphingosine-1-phosphate-enhanced Wnt5a promotes osteogenic differentiation in C3H10T1/2 cells.

    PubMed

    Hashimoto, Yoko; Kobayashi, Mari; Matsuzaki, Etsuko; Higashi, Katsumasa; Takahashi-Yanaga, Fumi; Takano, Aiko; Hirata, Masato; Nishimura, Fusanori

    2016-10-01

    In this study, we investigated the involvement of Wnt signaling in sphingosine-1-phosphate (S1P)-enhanced osteogenic differentiation of C3H10T1/2 pluripotent stem cells. We found that S1P enhanced the expression of Wnt5a and low-density lipoprotein receptor-related protein 5 or 6 (LRP5/6) during osteogenic differentiation. Wnt5a-neutralizing antibody inhibited S1P-enhanced expression of LRP5/6 and alkaline phosphatase, which are essential for osteogenic differentiation. Conversely, S1P did not affect endogenous canonical Wnt signaling. Taken together, S1P-enhanced Wnt5a promotes LRP5/6 expression, resulting in the trigger of osteogenic differentiation of C3H10T1/2 cells. These findings suggest a potential beneficial role for S1P in bone regeneration. PMID:27486054

  11. Sphingosine-1-phosphate-enhanced Wnt5a promotes osteogenic differentiation in C3H10T1/2 cells.

    PubMed

    Hashimoto, Yoko; Kobayashi, Mari; Matsuzaki, Etsuko; Higashi, Katsumasa; Takahashi-Yanaga, Fumi; Takano, Aiko; Hirata, Masato; Nishimura, Fusanori

    2016-10-01

    In this study, we investigated the involvement of Wnt signaling in sphingosine-1-phosphate (S1P)-enhanced osteogenic differentiation of C3H10T1/2 pluripotent stem cells. We found that S1P enhanced the expression of Wnt5a and low-density lipoprotein receptor-related protein 5 or 6 (LRP5/6) during osteogenic differentiation. Wnt5a-neutralizing antibody inhibited S1P-enhanced expression of LRP5/6 and alkaline phosphatase, which are essential for osteogenic differentiation. Conversely, S1P did not affect endogenous canonical Wnt signaling. Taken together, S1P-enhanced Wnt5a promotes LRP5/6 expression, resulting in the trigger of osteogenic differentiation of C3H10T1/2 cells. These findings suggest a potential beneficial role for S1P in bone regeneration.

  12. The roles of bile acids and sphingosine-1-phosphate signaling in the hepatobiliary diseases.

    PubMed

    Nagahashi, Masayuki; Yuza, Kizuki; Hirose, Yuki; Nakajima, Masato; Ramanathan, Rajesh; Hait, Nitai C; Hylemon, Phillip B; Zhou, Huiping; Takabe, Kazuaki; Wakai, Toshifumi

    2016-09-01

    Based on research carried out over the last decade, it has become increasingly evident that bile acids act not only as detergents, but also as important signaling molecules that exert various biological effects via activation of specific nuclear receptors and cell signaling pathways. Bile acids also regulate the expression of numerous genes encoding enzymes and proteins involved in the synthesis and metabolism of bile acids, glucose, fatty acids, and lipoproteins, as well as energy metabolism. Receptors activated by bile acids include, farnesoid X receptor α, pregnane X receptor, vitamin D receptor, and G protein-coupled receptors, TGR5, muscarinic receptor 2, and sphingosine-1-phosphate receptor (S1PR)2. The ligand of S1PR2, sphingosine-1-phosphate (S1P), is a bioactive lipid mediator that regulates various physiological and pathophysiological cellular processes. We have recently reported that conjugated bile acids, via S1PR2, activate and upregulate nuclear sphingosine kinase 2, increase nuclear S1P, and induce genes encoding enzymes and transporters involved in lipid and sterol metabolism in the liver. Here, we discuss the role of bile acids and S1P signaling in the regulation of hepatic lipid metabolism and in hepatobiliary diseases. PMID:27459945

  13. Elevation of serum sphingosine-1-phosphate attenuates impaired cardiac function in experimental sepsis

    PubMed Central

    Coldewey, Sina M.; Benetti, Elisa; Collino, Massimo; Pfeilschifter, Josef; Sponholz, Christoph; Bauer, Michael; Huwiler, Andrea; Thiemermann, Christoph

    2016-01-01

    Serum levels of the lipid mediator sphingosine-1-phosphate (S1P) are reduced in septic patients and are inversely associated with disease severity. We show that serum S1P is reduced in human sepsis and in murine models of sepsis. We then investigated whether pharmacological or genetic approaches that alter serum S1P may attenuate cardiac dysfunction and whether S1P signaling might serve as a novel theragnostic tool in sepsis. Mice were challenged with lipopolysaccharide and peptidoglycan (LPS/PepG). LPS/PepG resulted in an impaired systolic contractility and reduced serum S1P. Administration of the immunomodulator FTY720 increased serum S1P, improved impaired systolic contractility and activated the phosphoinositide 3-kinase (PI3K)-pathway in the heart. Cardioprotective effects of FTY720 were abolished following administration of a S1P receptor 2 (S1P2) antagonist or a PI3K inhibitor. Sphingosine kinase-2 deficient mice had higher endogenous S1P levels and the LPS/PepG-induced impaired systolic contractility was attenuated in comparison with wild-type mice. Cardioprotective effects of FTY720 were confirmed in polymicrobial sepsis. We show here for the first time that the impaired left ventricular systolic contractility in experimental sepsis is attenuated by FTY720. Mechanistically, our results indicate that activation of S1P2 by increased serum S1P and the subsequent activation of the PI3K-Akt survival pathway significantly contributes to the observed cardioprotective effect of FTY720. PMID:27277195

  14. Elevation of serum sphingosine-1-phosphate attenuates impaired cardiac function in experimental sepsis.

    PubMed

    Coldewey, Sina M; Benetti, Elisa; Collino, Massimo; Pfeilschifter, Josef; Sponholz, Christoph; Bauer, Michael; Huwiler, Andrea; Thiemermann, Christoph

    2016-01-01

    Serum levels of the lipid mediator sphingosine-1-phosphate (S1P) are reduced in septic patients and are inversely associated with disease severity. We show that serum S1P is reduced in human sepsis and in murine models of sepsis. We then investigated whether pharmacological or genetic approaches that alter serum S1P may attenuate cardiac dysfunction and whether S1P signaling might serve as a novel theragnostic tool in sepsis. Mice were challenged with lipopolysaccharide and peptidoglycan (LPS/PepG). LPS/PepG resulted in an impaired systolic contractility and reduced serum S1P. Administration of the immunomodulator FTY720 increased serum S1P, improved impaired systolic contractility and activated the phosphoinositide 3-kinase (PI3K)-pathway in the heart. Cardioprotective effects of FTY720 were abolished following administration of a S1P receptor 2 (S1P2) antagonist or a PI3K inhibitor. Sphingosine kinase-2 deficient mice had higher endogenous S1P levels and the LPS/PepG-induced impaired systolic contractility was attenuated in comparison with wild-type mice. Cardioprotective effects of FTY720 were confirmed in polymicrobial sepsis. We show here for the first time that the impaired left ventricular systolic contractility in experimental sepsis is attenuated by FTY720. Mechanistically, our results indicate that activation of S1P2 by increased serum S1P and the subsequent activation of the PI3K-Akt survival pathway significantly contributes to the observed cardioprotective effect of FTY720. PMID:27277195

  15. Molecular mechanism of sphingosine-1-phosphate action in Duchenne muscular dystrophy.

    PubMed

    Nguyen-Tran, Diem-Hang; Hait, Nitai C; Sperber, Henrik; Qi, Junlin; Fischer, Karin; Ieronimakis, Nick; Pantoja, Mario; Hays, Aislinn; Allegood, Jeremy; Reyes, Morayma; Spiegel, Sarah; Ruohola-Baker, Hannele

    2014-01-01

    Duchenne muscular dystrophy (DMD) is a lethal muscle-wasting disease. Studies in Drosophila showed that genetic increase of the levels of the bioactive sphingolipid sphingosine-1-phosphate (S1P) or delivery of 2-acetyl-5-tetrahydroxybutyl imidazole (THI), an S1P lyase inhibitor, suppresses dystrophic muscle degeneration. In the dystrophic mouse (mdx), upregulation of S1P by THI increases regeneration and muscle force. S1P can act as a ligand for S1P receptors and as a histone deacetylase (HDAC) inhibitor. Because Drosophila has no identified S1P receptors and DMD correlates with increased HDAC2 levels, we tested whether S1P action in muscle involves HDAC inhibition. Here we show that beneficial effects of THI treatment in mdx mice correlate with significantly increased nuclear S1P, decreased HDAC activity and increased acetylation of specific histone residues. Importantly, the HDAC2 target microRNA genes miR-29 and miR-1 are significantly upregulated, correlating with the downregulation of the miR-29 target Col1a1 in the diaphragm of THI-treated mdx mice. Further gene expression analysis revealed a significant THI-dependent decrease in inflammatory genes and increase in metabolic genes. Accordingly, S1P levels and functional mitochondrial activity are increased after THI treatment of differentiating C2C12 cells. S1P increases the capacity of the muscle cell to use fatty acids as an energy source, suggesting that THI treatment could be beneficial for the maintenance of energy metabolism in mdx muscles.

  16. Sphingosine kinase 1 and sphingosine-1-phosphate in oxidative stress evoked by 1-methyl-4-phenylpyridinium (MPP+) in human dopaminergic neuronal cells.

    PubMed

    Pyszko, Joanna; Strosznajder, Joanna B

    2014-08-01

    Sphingosine kinases (Sphk1/2) are crucial enzymes in regulation of the biostat between sphingosine-1-phosphate (S1P) and ceramide and play an important role in the pathogenesis/pathomechanism of Alzheimer's disease (AD). These enzymes synthesise S1P, which regulates neurotransmission, synaptic function and neuron cell proliferation, by activating five G protein-coupled receptors (S1P1-5). However, S1P synthesised by Sphk2 could be involved in amyloid β (Aβ) release by stimulation of Aβ precursor protein degradation. The significance of this bioactive sphingolipid in the pathogenesis of Parkinson's disease (PD) is unknown. The aim of our study was to investigate the expression level of Sphk1 and its role in human dopaminergic neuronal cell (SH-SY5Y) viability under oxidative stress, evoked by 1-methyl-4-phenylpyridinium (MPP+). Moreover, the mechanism of S1P action on the death signalling pathway in these experimental conditions was evaluated. Our study indicated marked downregulation of Sphk1 expression in this cellular PD model. Inhibition of Sphk1 decreased SH-SY5Y cell viability and concomitantly enhanced the reactive oxygen species (ROS) level. It was found that exogenous S1P (1 μM) exerted the neuroprotective effect by activation of Sphk1 and S1P1 receptor gene expression. Moreover, S1P downregulated Bax and harakiri, death protein 5 (Hrk/DP5) expression and enhanced cell viability in MPP+-treated cells. The neuroprotective mechanism of S1P is mainly dependent on S1P1 receptor signalling, which was indicated by using specific agonists and antagonists of S1P1 receptor. The results show that S1P and S1P1 receptor agonists protected a significant population of neuronal cells against death. PMID:24399507

  17. Benzyl butyl phthalate promotes breast cancer stem cell expansion via SPHK1/S1P/S1PR3 signaling.

    PubMed

    Wang, Yu-Chih; Tsai, Cheng-Fang; Chuang, Hsiao-Li; Chang, Yi-Chih; Chen, Hung-Sheng; Lee, Jau-Nan; Tsai, Eing-Mei

    2016-05-17

    Understanding the regulatory mechanisms unique to breast cancer stem cells (BCSCs) is required to control breast cancer metastasis. We found that phthalates promote BCSCs in human breast cancer cell cultures and xenograft tumors. A toxic phthalate, benzyl butyl phthalate (BBP), activated aryl hydrocarbon receptor in breast cancer cells to stimulate sphingosine kinase 1 (SPHK1)/sphingosine 1-phosphate (S1P)/sphingosine-1-phosphate receptor 3 (S1PR3) signaling and enhance formation of metastasis-initiating BCSCs. BBP induced histone modifications in S1PR3 in side population (SP) cells, but not in non-SP cells. SPHK1 or S1PR3 knockdown in breast cancer cells effectively reduced tumor growth and lung metastasis in vivo. Our findings suggest S1PR3 is a determinant of phthalate-driven breast cancer metastasis and a possible therapeutic target for regulating BCSC populations. Furthermore, the association between breast carcinogenesis and environmental pollutants has important implications for public health.

  18. Osteoblast-derived sphingosine 1-phosphate to induce proliferation and confer resistance to therapeutics to bone metastasis-derived prostate cancer cells.

    PubMed

    Brizuela, Leyre; Martin, Claire; Jeannot, Pauline; Ader, Isabelle; Gstalder, Cécile; Andrieu, Guillaume; Bocquet, Magalie; Laffosse, Jean-Michel; Gomez-Brouchet, Anne; Malavaud, Bernard; Sabbadini, Roger A; Cuvillier, Olivier

    2014-10-01

    Sphingosine 1-phosphate (S1P) plays important roles in cell proliferation, differentiation or survival mainly through its surface G-protein-coupled receptors S1P1-5. Bone represents the major site of metastasis for prostate cancer (CaP) cells, which rely on bone-derived factors to support their proliferation and resistance to therapeutics. In the present work we have found that conditioned medium (CM) from the MC3T3 osteoblastic cell line or primary murine and human osteoblast-like cells, as well as co-culture with MC3T3 stimulate proliferation of CaP lines in S1P-dependent manner. In addition, osteoblastic-derived S1P induces resistance of CaP cells to therapeutics including chemotherapy and radiotherapy. When S1P release from osteoblastic cells is decreased (inhibition of SphK1, knock-down of SphK1 or the S1P transporter, Spns2 by siRNA) or secreted S1P neutralized with anti-S1P antibody, the proliferative and survival effects of osteoblasts on CaP cells are abolished. Because of the paracrine nature of the signaling, we studied the role of the S1P receptors expressed on CaP cells in the communication with S1P secreted by osteoblasts. Strategies aimed at down-regulating S1P1, S1P2 or S1P3 (siRNA, antagonists), established the exclusive role of the S1P/S1P1 signaling between osteoblasts and CaP cells. Bone metastases from CaP are associated with osteoblastic differentiation resulting in abnormal bone formation. We show that the autocrine S1P/S1P3 signaling is central during differentiation to mature osteoblasts by regulating Runx2 level, a key transcription factor involved in osteoblastic maturation. Importantly, differentiated osteoblasts exhibited enhanced secretion of S1P and further stimulated CaP cell proliferation in a S1P-dependent manner. By establishing the dual role of osteoblast-borne S1P on both osteoblastic differentiation and CaP cell proliferation and survival, we uncover the importance of S1P in the bone metastatic microenvironment, which may open

  19. Osteoblast-derived sphingosine 1-phosphate to induce proliferation and confer resistance to therapeutics to bone metastasis-derived prostate cancer cells.

    PubMed

    Brizuela, Leyre; Martin, Claire; Jeannot, Pauline; Ader, Isabelle; Gstalder, Cécile; Andrieu, Guillaume; Bocquet, Magalie; Laffosse, Jean-Michel; Gomez-Brouchet, Anne; Malavaud, Bernard; Sabbadini, Roger A; Cuvillier, Olivier

    2014-10-01

    Sphingosine 1-phosphate (S1P) plays important roles in cell proliferation, differentiation or survival mainly through its surface G-protein-coupled receptors S1P1-5. Bone represents the major site of metastasis for prostate cancer (CaP) cells, which rely on bone-derived factors to support their proliferation and resistance to therapeutics. In the present work we have found that conditioned medium (CM) from the MC3T3 osteoblastic cell line or primary murine and human osteoblast-like cells, as well as co-culture with MC3T3 stimulate proliferation of CaP lines in S1P-dependent manner. In addition, osteoblastic-derived S1P induces resistance of CaP cells to therapeutics including chemotherapy and radiotherapy. When S1P release from osteoblastic cells is decreased (inhibition of SphK1, knock-down of SphK1 or the S1P transporter, Spns2 by siRNA) or secreted S1P neutralized with anti-S1P antibody, the proliferative and survival effects of osteoblasts on CaP cells are abolished. Because of the paracrine nature of the signaling, we studied the role of the S1P receptors expressed on CaP cells in the communication with S1P secreted by osteoblasts. Strategies aimed at down-regulating S1P1, S1P2 or S1P3 (siRNA, antagonists), established the exclusive role of the S1P/S1P1 signaling between osteoblasts and CaP cells. Bone metastases from CaP are associated with osteoblastic differentiation resulting in abnormal bone formation. We show that the autocrine S1P/S1P3 signaling is central during differentiation to mature osteoblasts by regulating Runx2 level, a key transcription factor involved in osteoblastic maturation. Importantly, differentiated osteoblasts exhibited enhanced secretion of S1P and further stimulated CaP cell proliferation in a S1P-dependent manner. By establishing the dual role of osteoblast-borne S1P on both osteoblastic differentiation and CaP cell proliferation and survival, we uncover the importance of S1P in the bone metastatic microenvironment, which may open

  20. AN EMERGING ROLE FOR THE LIPID MEDIATOR SPHINGOSINE-1-PHOSPHATE IN MAST CELL EFFECTOR FUNCTION AND ALLERGIC DISEASE*

    PubMed Central

    Olivera, Ana; Rivera, Juan

    2011-01-01

    Sphingosine-1-phosphate (S1P) plays important roles regulating functions of diverse biological systems, including the immune system. S1P affects immune cell function mostly by acting through its receptors at the cell membrane but it can also induce S1P receptor-independent responses in the cells where it is generated. S1P produced in allergically stimulated mast cells mediates degranulation, cytokine and lipid mediator production, and migration of mast cells towards antigen by mechanisms that are both S1P receptor-dependent and independent. Even in the absence of an antigen challenge, the differentiation and responsiveness of mast cells can be affected by chronic exposure to elevated S1P from a non-mast cell source, which may occur under pathophysiological conditions, potentially leading to the hyper-responsiveness of mast cells. The role of S1P extends beyond the regulation of the function of mast cells to the regulation of the surrounding or distal environment. S1P is exported out of antigen-stimulated mast cells and into the extracellular space and the resulting S1P gradient within the tissue may influence diverse surrounding tissue cells and several aspects of the allergic disease, such as inflammation or tissue remodeling. Furthermore, recent findings indicate that vasoactive mediators released systemically by mast cells induce the production of S1P in non-hematopoietic compartments, where it plays a role in regulating the vascular tone and reducing the hypotension characteristic of the anaphylactic shock and thus helping the recovery. The dual actions of S1P, promoting the immediate response of mast cells, while controlling the systemic consequences of mast cell activity will be discussed in detail. PMID:21713655

  1. Sphingosine Phosphate Lyase Regulates Murine Embryonic Stem Cell Proliferation and Pluripotency through an S1P2/STAT3 Signaling Pathway.

    PubMed

    Smith, Gaelen S; Kumar, Ashok; Saba, Julie D

    2013-06-24

    Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid that activates a family of G protein coupled-receptors (GPCRs) implicated in mammalian development, angiogenesis, immunity and tissue regeneration. S1P functions as a trophic factor for many cell types, including embryonic stem cells (ESCs). Sphingosine phosphate lyase (SPL) is an intracellular enzyme that catalyzes the irreversible degradation of S1P. We found SPL to be highly expressed in murine ESCs (mESCs). To investigate the role of SPL in mESC biology, we silenced SPL in mESCs via stable transfection with a lentiviral SPL-specific short hairpin RNA (shRNA) construct. SPL-knockdown (SPL-KD) mESCs showed a 5-fold increase in cellular S1P levels, increased proliferation rates and high expression of cell surface pluripotency markers SSEA1 and OCT4 compared to vector control cells. Compared to control mESCs, SPL-KD cells showed robust activation of STAT3 and a 10-fold increase in S1P2 expression. Inhibition of S1P2 or STAT3 reversed the proliferation and pluripotency phenotypes of SPL-KD mESCs. Further, inhibition of S1P2 attenuated, in a dose-dependent fashion, the high levels of OCT4 and STAT3 activation observed in SPL-KD mESCs. Finally, we showed that SPL-KD cells are capable of generating embryoid bodies from which muscle stem cells, called satellite cells, can be isolated. These findings demonstrate an important role for SPL in ESC homeostasis and suggest that SPL inhibition could facilitate ex vivo ESC expansion for therapeutic purposes.

  2. Sphingosine-1-phosphate lyase downregulation promotes colon carcinogenesis through STAT3-activated microRNAs

    PubMed Central

    Degagné, Emilie; Pandurangan, Ashok; Bandhuvula, Padmavathi; Kumar, Ashok; Eltanawy, Abeer; Zhang, Meng; Yoshinaga, Yuko; Nefedov, Mikhail; de Jong, Pieter J.; Fong, Loren G.; Young, Stephen G.; Bittman, Robert; Ahmedi, Yasmin; Saba, Julie D.

    2014-01-01

    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. PMID:25347472

  3. Emerging role of sphingosine-1-phosphate signaling in head and neck squamous cell carcinoma.

    PubMed

    Nema, Rajeev; Vishwakarma, Supriya; Agarwal, Rahul; Panday, Rajendra Kumar; Kumar, Ashok

    2016-01-01

    Head and neck squamous cell carcinoma (HNSCC) is the sixth most frequent cancer type, with an annual incidence of approximately half a million people worldwide. It has a high recurrence rate and an extremely low survival rate. This is due to limited availability of effective therapies to reduce the rate of recurrence, resulting in high morbidity and mortality of patients with advanced stages of the disease. HNSCC often develops resistance to chemotherapy and targeted drug therapy. Thus, to overcome the problem of drug resistance, there is a need to explore novel drug targets. Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid involved in inflammation, tumor progression, and angiogenesis. S1P is synthesized intracellularly by two sphingosine kinases (SphKs). It can be exported to the extracellular space, where it can activate a family of G-protein-coupled receptors. Alternatively, S1P can act as an intracellular second messenger. SphK1 regulates tumor progression, invasion, metastasis, and chemoresistance in HNSCC. SphK1 expression is highly elevated in advanced stage HNSCC tumors and correlates with poor survival. In this article, we review current knowledge regarding the role of S1P receptors and enzymes of S1P metabolism in HNSCC carcinogenesis. Furthermore, we summarize the current perspectives on therapeutic approaches for targeting S1P pathway for treating HNSCC. PMID:27330306

  4. Emerging role of sphingosine-1-phosphate signaling in head and neck squamous cell carcinoma

    PubMed Central

    Nema, Rajeev; Vishwakarma, Supriya; Agarwal, Rahul; Panday, Rajendra Kumar; Kumar, Ashok

    2016-01-01

    Head and neck squamous cell carcinoma (HNSCC) is the sixth most frequent cancer type, with an annual incidence of approximately half a million people worldwide. It has a high recurrence rate and an extremely low survival rate. This is due to limited availability of effective therapies to reduce the rate of recurrence, resulting in high morbidity and mortality of patients with advanced stages of the disease. HNSCC often develops resistance to chemotherapy and targeted drug therapy. Thus, to overcome the problem of drug resistance, there is a need to explore novel drug targets. Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid involved in inflammation, tumor progression, and angiogenesis. S1P is synthesized intracellularly by two sphingosine kinases (SphKs). It can be exported to the extracellular space, where it can activate a family of G-protein-coupled receptors. Alternatively, S1P can act as an intracellular second messenger. SphK1 regulates tumor progression, invasion, metastasis, and chemoresistance in HNSCC. SphK1 expression is highly elevated in advanced stage HNSCC tumors and correlates with poor survival. In this article, we review current knowledge regarding the role of S1P receptors and enzymes of S1P metabolism in HNSCC carcinogenesis. Furthermore, we summarize the current perspectives on therapeutic approaches for targeting S1P pathway for treating HNSCC. PMID:27330306

  5. The S1P/S1PR2 axis regulates early airway T cell infiltration in murine mast cell-dependent acute allergic responses

    PubMed Central

    Oskeritzian, Carole A.; Hait, Nitai C.; Wedman, Piper; Chumanevich, Alena; Kolawole, Elizabeth M.; Price, Megan M.; Falanga, Yves T.; Harikumar, Kuzhuvelil B.; Ryan, John J.; Milstien, Sheldon; Sabbadini, Roger; Spiegel, Sarah

    2014-01-01

    Background Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid produced by mast cells (MC) upon cross-linking of their high affinity receptors for IgE by antigen (Ag) that can amplify MC responses by binding to its S1P receptors. Acute MC-dependent allergic reaction can lead to systemic shock but the early events of its development in lung tissues have not been investigated, and S1P functions in the onset of allergic processes remain to be examined. Objective We used a highly specific neutralizing anti-S1P antibody (mAb) and an S1P receptor 2 (S1PR2) antagonist, JTE-013, to study S1P and S1PR2 signaling contributions to MC- and IgE-dependent airway allergic responses in mice within minutes after Ag challenge. Methods Allergic reaction was triggered by a single intraperitoneal (i.p.) dose of Ag in sensitized mice pre-treated i.p. with anti-S1P or isotype control mAb, or JTE-013 or vehicle prior to Ag challenge. Results Kinetics experiments revealed early pulmonary infiltration of mostly T cells around blood vessels of sensitized mice 20 minutes post-Ag exposure. Pre-treatment with anti-S1P mAb inhibited in vitro MC activation, as well as in vivo development of airway infiltration and MC activation, reducing serum levels of histamine, cytokines and the chemokines MCP-1/CCL2, MIP-1α/CCL3 and RANTES/CCL5. S1PR2 antagonism or deficiency, or MC deficiency recapitulated these results. Both in vitro and in vivo experiments demonstrated MC S1PR2 dependency for chemokine release and the necessity for signal transducer and activator of transcription 3 (Stat3) activation. Conclusion Activation of S1PR2 by S1P and downstream Stat3 signaling in MC regulate early T cell recruitment to antigen-challenged lungs by chemokine production. PMID:25512083

  6. Sphingosine 1-phosphate induces platelet/endothelial cell adhesion molecule-1 phosphorylation in human endothelial cells through cSrc and Fyn.

    PubMed

    Huang, Yu-Ting; Chen, Shee-Uan; Chou, Chia-Hong; Lee, Hsinyu

    2008-08-01

    Sphingosine 1-phosphate (S1P) is a multifunctional phospholipid which acts through a specific family of G protein-coupled receptors. Platelet/endothelial cell adhesion molecule-1 (PECAM-1) form trans-homophilic binding at lateral cell border. Upon stimulation, its cytoplasmic tyrosine residues could be phosphorylated and interact with various downstream signaling molecules. In this study, we demonstrated that S1P induced PECAM-1 tyrosine phosphorylation in human umbilical cord vein cells (HUVECs). By pharmacological inhibitors, it was suggested that G(i) and Src family kinases were involved in PECAM-1 phosphorylation. Moreover, cSrc and Fyn siRNA significantly suppressed S1P-induced PECAM-1 phosphorylation. These results suggested that S1P-induced PECAM-1 phosphorylation through G(i) and subsequent cSrc and Fyn. Our findings provide further understanding of S1P and PECAM-1 signaling as well as their functions in endothelial cells. PMID:18502612

  7. Binding Characteristics of Sphingosine-1-Phosphate to ApoM hints to Assisted Release Mechanism via the ApoM Calyx-Opening.

    PubMed

    Zhang, Hansi; Pluhackova, Kristyna; Jiang, Zhenyan; Böckmann, Rainer A

    2016-01-01

    Sphingosine-1-phosphate (S1P) is a lysophospholipid mediator carried by the HDL-associated apoM protein in blood, regulating many physiological processes by activating the G protein-coupled S1P receptor in mammals. Despite the solved crystal structure of the apoM-S1P complex, the mechanism of S1P release from apoM as a part of the S1P pathway is unknown. Here, the dynamics of the wild type apoM-S1P complex as well as of mutants were investigated by means of atomistic molecular dynamics simulations. The potential of mean force for S1P unbinding from apoM reflected a large binding strength of more than 60 kJ/mol. This high unbinding free energy for S1P underlines the observed specificity of the physiological effects of S1P as it suggests that the spontaneous release of S1P from apoM is unlikely. Instead, S1P release and thus the control of this bioactive lipid probably requires the tight interaction with other molecules, e.g. with the S1P receptor. Mutations of specific S1P anchoring residues of apoM decreased the energetic barrier by up to 20 kJ/mol. Moreover, the ligand-free apoM protein is shown to adopt a more open upper hydrophilic binding pocket and to result in complete closure of the lower hydrophobic cavity, suggesting a mechanism for adjusting the gate for ligand access. PMID:27476912

  8. Binding Characteristics of Sphingosine-1-Phosphate to ApoM hints to Assisted Release Mechanism via the ApoM Calyx-Opening

    PubMed Central

    Zhang, Hansi; Pluhackova, Kristyna; Jiang, Zhenyan; Böckmann, Rainer A.

    2016-01-01

    Sphingosine-1-phosphate (S1P) is a lysophospholipid mediator carried by the HDL-associated apoM protein in blood, regulating many physiological processes by activating the G protein-coupled S1P receptor in mammals. Despite the solved crystal structure of the apoM-S1P complex, the mechanism of S1P release from apoM as a part of the S1P pathway is unknown. Here, the dynamics of the wild type apoM-S1P complex as well as of mutants were investigated by means of atomistic molecular dynamics simulations. The potential of mean force for S1P unbinding from apoM reflected a large binding strength of more than 60 kJ/mol. This high unbinding free energy for S1P underlines the observed specificity of the physiological effects of S1P as it suggests that the spontaneous release of S1P from apoM is unlikely. Instead, S1P release and thus the control of this bioactive lipid probably requires the tight interaction with other molecules, e.g. with the S1P receptor. Mutations of specific S1P anchoring residues of apoM decreased the energetic barrier by up to 20 kJ/mol. Moreover, the ligand-free apoM protein is shown to adopt a more open upper hydrophilic binding pocket and to result in complete closure of the lower hydrophobic cavity, suggesting a mechanism for adjusting the gate for ligand access. PMID:27476912

  9. Migration of germline progenitor cells is directed by sphingosine-1-phosphate signalling in a basal chordate.

    PubMed

    Kassmer, Susannah H; Rodriguez, Delany; Langenbacher, Adam D; Bui, Connor; De Tomaso, Anthony W

    2015-01-01

    The colonial ascidian Botryllus schlosseri continuously regenerates entire bodies in an asexual budding process. The germ line of the newly developing bodies is derived from migrating germ cell precursors, but the signals governing this homing process are unknown. Here we show that germ cell precursors can be prospectively isolated based on expression of aldehyde dehydrogenase and integrin alpha-6, and that these cells express germ cell markers such as vasa, pumilio and piwi, as well as sphingosine-1-phosphate receptor. In vitro, sphingosine-1-phosphate (S1P) stimulates migration of germ cells, which depends on integrin alpha-6 activity. In vivo, S1P signalling is essential for homing of germ cells to newly developing bodies. S1P is generated by sphingosine kinase in the developing germ cell niche and degraded by lipid phosphate phosphatase in somatic tissues. These results demonstrate a previously unknown role of the S1P signalling pathway in germ cell migration in the ascidian Botryllus schlosseri. PMID:26456232

  10. Migration of germline progenitor cells is directed by sphingosine-1-phosphate signalling in a basal chordate

    PubMed Central

    Kassmer, Susannah H.; Rodriguez, Delany; Langenbacher, Adam D.; Bui, Connor; De Tomaso, Anthony W.

    2015-01-01

    The colonial ascidian Botryllus schlosseri continuously regenerates entire bodies in an asexual budding process. The germ line of the newly developing bodies is derived from migrating germ cell precursors, but the signals governing this homing process are unknown. Here we show that germ cell precursors can be prospectively isolated based on expression of aldehyde dehydrogenase and integrin alpha-6, and that these cells express germ cell markers such as vasa, pumilio and piwi, as well as sphingosine-1-phosphate receptor. In vitro, sphingosine-1-phosphate (S1P) stimulates migration of germ cells, which depends on integrin alpha-6 activity. In vivo, S1P signalling is essential for homing of germ cells to newly developing bodies. S1P is generated by sphingosine kinase in the developing germ cell niche and degraded by lipid phosphate phosphatase in somatic tissues. These results demonstrate a previously unknown role of the S1P signalling pathway in germ cell migration in the ascidian Botryllus schlosseri. PMID:26456232

  11. Essential role for SphK1/S1P signaling to regulate hypoxia-inducible factor 2α expression and activity in cancer

    PubMed Central

    Bouquerel, P; Gstalder, C; Müller, D; Laurent, J; Brizuela, L; Sabbadini, R A; Malavaud, B; Pyronnet, S; Martineau, Y; Ader, I; Cuvillier, O

    2016-01-01

    The sphingosine kinase-1/sphingosine 1-phosphate (SphK1/S1P) signaling pathway has been reported to modulate the expression of the canonical transcription factor hypoxia-inducible HIF-1α in multiple cell lineages. HIF-2α is also frequently overexpressed in solid tumors but its role has been mostly studied in clear cell renal cell carcinoma (ccRCC), the most common form of kidney cancer, where HIF-2α has been established as a driver of a more aggressive disease. In this study, the role of SphK1/S1P signaling with regard to HIF-2α was investigated in various cancer cell models including ccRCC cells. Under hypoxic conditions or in ccRCC lacking a functional von Hippel-Lindau (VHL) gene and expressing high levels of HIF-2α, SphK1 activity controls HIF-2α expression and transcriptional activity through a phospholipase D (PLD)-driven mechanism. SphK1 silencing promotes a VHL-independent HIF-2α loss of expression and activity and reduces cell proliferation in ccRCC. Importantly, downregulation of SphK1 is associated with impaired Akt and mTOR signaling in ccRCC. Taking advantage of a monoclonal antibody neutralizing extracellular S1P, we show that inhibition of S1P extracellular signaling blocks HIF-2α accumulation in ccRCC cell lines, an effect mimicked when the S1P transporter Spns2 or the S1P receptor 1 (S1P1) is silenced. Here, we report the first evidence that the SphK1/S1P signaling pathway regulates the transcription factor hypoxia-inducible HIF-2α in diverse cancer cell lineages notably ccRCC, where HIF-2α has been established as a driver of a more aggressive disease. These findings demonstrate that SphK1/S1P signaling may act as a canonical regulator of HIF-2α expression in ccRCC, giving support to its inhibition as a therapeutic strategy that could contribute to reduce HIF-2 activity in ccRCC. PMID:26974204

  12. Filamin A Expression Negatively Regulates Sphingosine-1-Phosphate-Induced NF-κB Activation in Melanoma Cells by Inhibition of Akt Signaling.

    PubMed

    Campos, Ludmila S; Rodriguez, Yamila I; Leopoldino, Andreia M; Hait, Nitai C; Lopez Bergami, Pablo; Castro, Melina G; Sanchez, Emilse S; Maceyka, Michael; Spiegel, Sarah; Alvarez, Sergio E

    2015-01-01

    Sphingosine-1-phosphate (S1P) is a bioactive lipid mediator that regulates many processes in inflammation and cancer. S1P is a ligand for five G-protein-coupled receptors, S1PR1 to -5, and also has important intracellular actions. Previously, we showed that intracellular S1P is involved in tumor necrosis factor alpha (TNF)-induced NF-κB activation in melanoma cell lines that express filamin A (FLNA). Here, we show that extracellular S1P activates NF-κB only in melanoma cells that lack FLNA. In these cells, S1P, but not TNF, promotes IκB kinase (IKK) and p65 phosphorylation, IκBα degradation, p65 nuclear translocation, and NF-κB reporter activity. NF-κB activation induced by S1P was mediated via S1PR1 and S1PR2. Exogenous S1P enhanced the phosphorylation of protein kinase Cδ (PKCδ), and its downregulation reduced S1P-induced the phosphorylation of IKK and p65. In addition, silencing of Bcl10 also inhibited S1P-induced IKK phosphorylation. Surprisingly, S1P reduced Akt activation in melanoma cells that express FLNA, whereas in the absence of FLNA, high phosphorylation levels of Akt were maintained, enabling S1P-mediated NF-κB signaling. In accord, inhibition of Akt suppressed S1P-mediated IKK and p65 phosphorylation and degradation of IκBα. Hence, these results support a negative role of FLNA in S1P-mediated NF-κB activation in melanoma cells through modulation of Akt. PMID:26552704

  13. Filamin A Expression Negatively Regulates Sphingosine-1-Phosphate-Induced NF-κB Activation in Melanoma Cells by Inhibition of Akt Signaling

    PubMed Central

    Campos, Ludmila S.; Rodriguez, Yamila I.; Leopoldino, Andreia M.; Hait, Nitai C.; Lopez Bergami, Pablo; Castro, Melina G.; Sanchez, Emilse S.; Maceyka, Michael

    2015-01-01

    Sphingosine-1-phosphate (S1P) is a bioactive lipid mediator that regulates many processes in inflammation and cancer. S1P is a ligand for five G-protein-coupled receptors, S1PR1 to -5, and also has important intracellular actions. Previously, we showed that intracellular S1P is involved in tumor necrosis factor alpha (TNF)-induced NF-κB activation in melanoma cell lines that express filamin A (FLNA). Here, we show that extracellular S1P activates NF-κB only in melanoma cells that lack FLNA. In these cells, S1P, but not TNF, promotes IκB kinase (IKK) and p65 phosphorylation, IκBα degradation, p65 nuclear translocation, and NF-κB reporter activity. NF-κB activation induced by S1P was mediated via S1PR1 and S1PR2. Exogenous S1P enhanced the phosphorylation of protein kinase Cδ (PKCδ), and its downregulation reduced S1P-induced the phosphorylation of IKK and p65. In addition, silencing of Bcl10 also inhibited S1P-induced IKK phosphorylation. Surprisingly, S1P reduced Akt activation in melanoma cells that express FLNA, whereas in the absence of FLNA, high phosphorylation levels of Akt were maintained, enabling S1P-mediated NF-κB signaling. In accord, inhibition of Akt suppressed S1P-mediated IKK and p65 phosphorylation and degradation of IκBα. Hence, these results support a negative role of FLNA in S1P-mediated NF-κB activation in melanoma cells through modulation of Akt. PMID:26552704

  14. A map of sphingosine 1-phosphate distribution in the spleen

    PubMed Central

    Ramos-Perez, Willy D.; Fang, Victoria; Escalante-Alcalde, Diana; Cammer, Michael; Schwab, Susan R.

    2015-01-01

    Despite the importance of signaling lipids, many questions remain about their function because we have few tools to chart lipid gradients in vivo. Here we describe a sphingosine 1-phosphate (S1P) reporter mouse, and use this mouse to define S1P distribution in the spleen. Surprisingly, the presence of blood does not predict the concentration of signaling-available S1P. Large areas of the red pulp are S1P-low, while S1P can be sensed by cells inside the white pulp near the marginal sinus. Lipid phosphate phosphatase 3 maintains low S1P concentrations in the spleen, and enables efficient marginal zone B cell shuttling. The exquisitely tight regulation of S1P availability may explain how a single lipid can simultaneously orchestrate many immune cell movements. PMID:26502404

  15. Sphingosine-1-phosphate induces human endothelial VEGF and MMP-2 production via transcription factor ZNF580: Novel insights into angiogenesis

    SciTech Connect

    Sun, Hui-Yan; Wei, Shu-Ping; Xu, Rui-Cheng; Xu, Peng-Xiao; Zhang, Wen-Cheng

    2010-05-07

    Sphingosine-1-phosphate (S1P)-induced migration and proliferation of endothelial cells are critical for angiogenesis. C2H2-zinc finger (ZNF) proteins usually play an essential role in altering gene expression and regulating the angiogenesis. The aim of this study is to investigate whether a novel human C2H2-zinc finger gene ZNF580 (Gene ID: 51157) is involved in the migration and proliferation of endothelial cells stimulated by S1P. Our study shows that EAhy926 endothelial cells express S1P1, S1P3 and S1P5 receptors. Furthermore, S1P upregulates both ZNF580 mRNA and protein levels in a concentration- and time-dependent manner. SB203580, the specific inhibitor of the p38 mitogen-activated protein kinase (p38 MAPK) pathway, blocks the S1P-induced upregulation of ZNF580. Moreover, overexpression/downexpression of ZNF580 in EAhy926 cells leads to the enhancement/decrease of matrix metalloproteinase-2 (MMP-2) and vascular endothelial growth factor (VEGF) expression as well as the migration and proliferation of EAhy926 endothelial cells. These results elucidate the important role that ZNF580 plays in the process of migration and proliferation of endothelial cells, which provides a foundation for a novel approach to regulate angiogenesis.

  16. Identification and characterization of a mirror-image oligonucleotide that binds and neutralizes sphingosine 1-phosphate, a central mediator of angiogenesis.

    PubMed

    Purschke, Werner G; Hoehlig, Kai; Buchner, Klaus; Zboralski, Dirk; Schwoebel, Frank; Vater, Axel; Klussmann, Sven

    2014-08-15

    The sphingolipid S1P (sphingosine 1-phosphate) is known to be involved in a number of pathophysiological conditions such as cancer, autoimmune diseases and fibrosis. It acts extracellularly through a set of five G-protein-coupled receptors, but its intracellular actions are also well documented. Employing in vitro selection techniques, we identified an L-aptamer (Spiegelmer®) to S1P designated NOX-S93. The binding affinity of NOX-S93 to S1P had a Kd value of 4.3 nM. The Spiegelmer® shows equal binding to dihydro-S1P, but no cross-reactivity to the related lipids sphingosine, lysophosphatidic acid, ceramide, ceramide-1-phosphate or sphingosine phosphocholine. In stably transfected CHO (Chinese-hamster ovary) cell lines expressing the S1P receptors S1PR1 or S1PR3, NOX-S93 inhibits S1P-mediated β-arrestin recruitment and intracellular calcium release respectively, with IC50 values in the low nanomolar range. The pro-angiogenic activity of S1P, and of the growth factors VEGF-A (vascular endothelial growth factor-A), FGF-2 (fibroblast growth factor-2) and IGF-1 (insulin-like growth factor-1), was effectively blocked by NOX-S93 in a cellular angiogenesis assay employing primary human endothelial cells. These data provide further evidence for the relevance of extracellular S1P as a central mediator of angiogenesis, suggesting pharmacological S1P neutralization as a promising treatment alternative to current anti-angiogenesis approaches. PMID:24832383

  17. Sphingosine-1-Phosphate Signaling Regulates Myogenic Responsiveness in Human Resistance Arteries

    PubMed Central

    Slack, Daniel L.; Burnstein, Marcus J.; Errett, Lee; Bonneau, Daniel; Latter, David; Rotstein, Ori D.; Bolz, Steffen-Sebastian; Lidington, Darcy; Voigtlaender-Bolz, Julia

    2015-01-01

    We recently identified sphingosine-1-phosphate (S1P) signaling and the cystic fibrosis transmembrane conductance regulator (CFTR) as prominent regulators of myogenic responsiveness in rodent resistance arteries. However, since rodent models frequently exhibit limitations with respect to human applicability, translation is necessary to validate the relevance of this signaling network for clinical application. We therefore investigated the significance of these regulatory elements in human mesenteric and skeletal muscle resistance arteries. Mesenteric and skeletal muscle resistance arteries were isolated from patient tissue specimens collected during colonic or cardiac bypass surgery. Pressure myography assessments confirmed endothelial integrity, as well as stable phenylephrine and myogenic responses. Both human mesenteric and skeletal muscle resistance arteries (i) express critical S1P signaling elements, (ii) constrict in response to S1P and (iii) lose myogenic responsiveness following S1P receptor antagonism (JTE013). However, while human mesenteric arteries express CFTR, human skeletal muscle resistance arteries do not express detectable levels of CFTR protein. Consequently, modulating CFTR activity enhances myogenic responsiveness only in human mesenteric resistance arteries. We conclude that human mesenteric and skeletal muscle resistance arteries are a reliable and consistent model for translational studies. We demonstrate that the core elements of an S1P-dependent signaling network translate to human mesenteric resistance arteries. Clear species and vascular bed variations are evident, reinforcing the critical need for further translational study. PMID:26367262

  18. Sphingosine-1-phosphate mediates epidermal growth factor-induced muscle satellite cell activation

    SciTech Connect

    Nagata, Yosuke Ohashi, Kazuya; Wada, Eiji; Yuasa, Yuki; Shiozuka, Masataka; Nonomura, Yoshiaki; Matsuda, Ryoichi

    2014-08-01

    Skeletal muscle can regenerate repeatedly due to the presence of resident stem cells, called satellite cells. Because satellite cells are usually quiescent, they must be activated before participating in muscle regeneration in response to stimuli such as injury, overloading, and stretch. Although satellite cell activation is a crucial step in muscle regeneration, little is known of the molecular mechanisms controlling this process. Recent work showed that the bioactive lipid sphingosine-1-phosphate (S1P) plays crucial roles in the activation, proliferation, and differentiation of muscle satellite cells. We investigated the role of growth factors in S1P-mediated satellite cell activation. We found that epidermal growth factor (EGF) in combination with insulin induced proliferation of quiescent undifferentiated mouse myoblast C2C12 cells, which are also known as reserve cells, in serum-free conditions. Sphingosine kinase activity increased when reserve cells were stimulated with EGF. Treatment of reserve cells with the D-erythro-N,N-dimethylsphingosine, Sphingosine Kinase Inhibitor, or siRNA duplexes specific for sphingosine kinase 1, suppressed EGF-induced C2C12 activation. We also present the evidence showing the S1P receptor S1P2 is involved in EGF-induced reserve cell activation. Moreover, we demonstrated a combination of insulin and EGF promoted activation of satellite cells on single myofibers in a manner dependent on SPHK and S1P2. Taken together, our observations show that EGF-induced satellite cell activation is mediated by S1P and its receptor. - Highlights: • EGF in combination with insulin induces proliferation of quiescent C2C12 cells. • Sphingosine kinase activity increases when reserve cells are stimulated with EGF. • EGF-induced activation of reserve cells is dependent on sphingosine kinase and ERK. • The S1P receptor S1P2 is involved in EGF-induced reserve cell activation. • EGF-induced reserve cell activation is mediated by S1P and its

  19. Sphingosine 1-phosphate signaling pathway in inner ear biology. New therapeutic strategies for hearing loss?

    PubMed

    Romero-Guevara, Ricardo; Cencetti, Francesca; Donati, Chiara; Bruni, Paola

    2015-01-01

    Hearing loss is one of the most prevalent conditions around the world, in particular among people over 60 years old. Thus, an increase of this affection is predicted as result of the aging process in our population. In this context, it is important to further explore the function of molecular targets involved in the biology of inner ear sensory cells to better individuate new candidates for therapeutic application. One of the main causes of deafness resides into the premature death of hair cells and auditory neurons. In this regard, neurotrophins and growth factors such as insulin like growth factor are known to be beneficial by favoring the survival of these cells. An elevated number of published data in the last 20 years have individuated sphingolipids not only as structural components of biological membranes but also as critical regulators of key biological processes, including cell survival. Ceramide, formed by catabolism of sphingomyelin (SM) and other complex sphingolipids, is a strong inducer of apoptotic pathway, whereas sphingosine 1-phosphate (S1P), generated by cleavage of ceramide to sphingosine and phosphorylation catalyzed by two distinct sphingosine kinase (SK) enzymes, stimulates cell survival. Interestingly S1P, by acting as intracellular mediator or as ligand of a family of five distinct S1P receptors (S1P1-S1P5), is a very powerful bioactive sphingolipid, capable of triggering also other diverse cellular responses such as cell migration, proliferation and differentiation, and is critically involved in the development and homeostasis of several organs and tissues. Although new interesting data have become available, the information on S1P pathway and other sphingolipids in the biology of the inner ear is limited. Nonetheless, there are several lines of evidence implicating these signaling molecules during neurogenesis in other cell populations. In this review, we discuss the role of S1P during inner ear development, also as guidance for future

  20. Sphingosine 1-phosphate signaling pathway in inner ear biology. New therapeutic strategies for hearing loss?

    PubMed Central

    Romero-Guevara, Ricardo; Cencetti, Francesca; Donati, Chiara; Bruni, Paola

    2015-01-01

    Hearing loss is one of the most prevalent conditions around the world, in particular among people over 60 years old. Thus, an increase of this affection is predicted as result of the aging process in our population. In this context, it is important to further explore the function of molecular targets involved in the biology of inner ear sensory cells to better individuate new candidates for therapeutic application. One of the main causes of deafness resides into the premature death of hair cells and auditory neurons. In this regard, neurotrophins and growth factors such as insulin like growth factor are known to be beneficial by favoring the survival of these cells. An elevated number of published data in the last 20 years have individuated sphingolipids not only as structural components of biological membranes but also as critical regulators of key biological processes, including cell survival. Ceramide, formed by catabolism of sphingomyelin (SM) and other complex sphingolipids, is a strong inducer of apoptotic pathway, whereas sphingosine 1-phosphate (S1P), generated by cleavage of ceramide to sphingosine and phosphorylation catalyzed by two distinct sphingosine kinase (SK) enzymes, stimulates cell survival. Interestingly S1P, by acting as intracellular mediator or as ligand of a family of five distinct S1P receptors (S1P1–S1P5), is a very powerful bioactive sphingolipid, capable of triggering also other diverse cellular responses such as cell migration, proliferation and differentiation, and is critically involved in the development and homeostasis of several organs and tissues. Although new interesting data have become available, the information on S1P pathway and other sphingolipids in the biology of the inner ear is limited. Nonetheless, there are several lines of evidence implicating these signaling molecules during neurogenesis in other cell populations. In this review, we discuss the role of S1P during inner ear development, also as guidance for future

  1. The Therapeutic Effects of Human Mesenchymal Stem Cells Primed with Sphingosine-1 Phosphate on Pulmonary Artery Hypertension

    PubMed Central

    Kang, Hyunsook; Kim, Kang-Hyun; Lim, Jisun; Kim, You-Sun; Heo, Jinbeom; Choi, Jongjin; Jeong, Jaeho; Kim, YongHwan; Kim, Seong Who; Oh, Yeon-Mok; Choo, Myung-Soo; Son, Jaekyoung; Kim, Su Jung; Yoo, Hyun Ju; Oh, Wonil; Choi, Soo Jin

    2015-01-01

    Stem cell (SC) therapy has become a potential treatment modality for pulmonary artery hypertension (PAH), but the efficacy of human SC and priming effects have not yet been established. The mobilization and homing of hematopoietic stem cells (HSCs) are modulated by priming factors that include a bioactive lipid, sphingosine-1-phosphate (S1P), which stimulates CXCR4 receptor kinase signaling. Here, we show that priming human mesenchymal stem cells (MSCs) with S1P enhances their therapeutic efficacy in PAH. Human MSCs, similar to HSCs, showed stronger chemoattraction to S1P in transwell assays. Concomitantly, MSCs treated with 0.2 μM S1P showed increased phosphorylation of both MAPKp42/44 and AKT protein compared with nonprimed MSCs. Furthermore, S1P-primed MSCs potentiated colony forming unit-fibroblast, anti-inflammatory, and angiogenic activities of MSCs in culture. In a PAH animal model induced by subcutaneously injected monocrotaline, administration of human cord blood-derived MSCs (hCB-MSCs) or S1P-primed cells significantly attenuated the elevated right ventricular systolic pressure. Notably, S1P-primed CB-MSCs, but not unprimed hCB-MSCs, also elicited a significant reduction in the right ventricular weight ratio and pulmonary vascular wall thickness. S1P-primed MSCs enhanced the expression of several genes responsible for stem cell trafficking and angiogenesis, increasing the density of blood vessels in the damaged lungs. Thus, this study demonstrates that human MSCs have potential utility for the treatment of PAH, and that S1P priming increases the effects of SC therapy by enhancing cardiac and vascular remodeling. By optimizing this protocol in future studies, SC therapy might form a basis for clinical trials to treat human PAH. PMID:25761906

  2. Sphingosine-1-phosphate mediates epidermal growth factor-induced muscle satellite cell activation.

    PubMed

    Nagata, Yosuke; Ohashi, Kazuya; Wada, Eiji; Yuasa, Yuki; Shiozuka, Masataka; Nonomura, Yoshiaki; Matsuda, Ryoichi

    2014-08-01

    Skeletal muscle can regenerate repeatedly due to the presence of resident stem cells, called satellite cells. Because satellite cells are usually quiescent, they must be activated before participating in muscle regeneration in response to stimuli such as injury, overloading, and stretch. Although satellite cell activation is a crucial step in muscle regeneration, little is known of the molecular mechanisms controlling this process. Recent work showed that the bioactive lipid sphingosine-1-phosphate (S1P) plays crucial roles in the activation, proliferation, and differentiation of muscle satellite cells. We investigated the role of growth factors in S1P-mediated satellite cell activation. We found that epidermal growth factor (EGF) in combination with insulin induced proliferation of quiescent undifferentiated mouse myoblast C2C12 cells, which are also known as reserve cells, in serum-free conditions. Sphingosine kinase activity increased when reserve cells were stimulated with EGF. Treatment of reserve cells with the D-erythro-N,N-dimethylsphingosine, Sphingosine Kinase Inhibitor, or siRNA duplexes specific for sphingosine kinase 1, suppressed EGF-induced C2C12 activation. We also present the evidence showing the S1P receptor S1P2 is involved in EGF-induced reserve cell activation. Moreover, we demonstrated a combination of insulin and EGF promoted activation of satellite cells on single myofibers in a manner dependent on SPHK and S1P2. Taken together, our observations show that EGF-induced satellite cell activation is mediated by S1P and its receptor.

  3. Sphingosine 1-Phosphate Activation of EGFR As a Novel Target for Meningitic Escherichia coli Penetration of the Blood-Brain Barrier

    PubMed Central

    Wang, Xiangru; Maruvada, Ravi; Morris, Andrew J.; Liu, Jun O.; Baek, Dong Jae; Kim, Kwang Sik

    2016-01-01

    Central nervous system (CNS) infection continues to be an important cause of mortality and morbidity, necessitating new approaches for investigating its pathogenesis, prevention and therapy. Escherichia coli is the most common Gram-negative bacillary organism causing meningitis, which develops following penetration of the blood–brain barrier (BBB). By chemical library screening, we identified epidermal growth factor receptor (EGFR) as a contributor to E. coli invasion of the BBB in vitro. Here, we obtained the direct evidence that CNS-infecting E. coli exploited sphingosine 1-phosphate (S1P) for EGFR activation in penetration of the BBB in vitro and in vivo. We found that S1P was upstream of EGFR and participated in EGFR activation through S1P receptor as well as through S1P-mediated up-regulation of EGFR-related ligand HB-EGF, and blockade of S1P function through targeting sphingosine kinase and S1P receptor inhibited EGFR activation, and also E. coli invasion of the BBB. We further found that both S1P and EGFR activations occurred in response to the same E. coli proteins (OmpA, FimH, NlpI), and that S1P and EGFR promoted E. coli invasion of the BBB by activating the downstream c-Src. These findings indicate that S1P and EGFR represent the novel host targets for meningitic E. coli penetration of the BBB, and counteracting such targets provide a novel approach for controlling E. coli meningitis in the era of increasing resistance to conventional antibiotics. PMID:27711202

  4. Increased mRNA Levels of Sphingosine Kinases and S1P Lyase and Reduced Levels of S1P Were Observed in Hepatocellular Carcinoma in Association with Poorer Differentiation and Earlier Recurrence

    PubMed Central

    Uranbileg, Baasanjav; Ikeda, Hitoshi; Kurano, Makoto; Enooku, Kenichiro; Sato, Masaya; Saigusa, Daisuke; Aoki, Junken; Ishizawa, Takeaki; Hasegawa, Kiyoshi; Kokudo, Norihiro; Yatomi, Yutaka

    2016-01-01

    Although sphingosine 1-phosphate (S1P) has been reported to play an important role in cancer pathophysiology, little is known about S1P and hepatocellular carcinoma (HCC). To clarify the relationship between S1P and HCC, 77 patients with HCC who underwent surgical treatment were consecutively enrolled in this study. In addition, S1P and its metabolites were quantitated by LC-MS/MS. The mRNA levels of sphingosine kinases (SKs), which phosphorylate sphingosine to generate S1P, were increased in HCC tissues compared with adjacent non-HCC tissues. Higher mRNA levels of SKs in HCC were associated with poorer differentiation and microvascular invasion, whereas a higher level of SK2 mRNA was a risk factor for intra- and extra-hepatic recurrence. S1P levels, however, were unexpectedly reduced in HCC compared with non-HCC tissues, and increased mRNA levels of S1P lyase (SPL), which degrades S1P, were observed in HCC compared with non-HCC tissues. Higher SPL mRNA levels in HCC were associated with poorer differentiation. Finally, in HCC cell lines, inhibition of the expression of SKs or SPL by siRNA led to reduced proliferation, invasion and migration, whereas overexpression of SKs or SPL enhanced proliferation. In conclusion, increased SK and SPL mRNA expression along with reduced S1P levels were more commonly observed in HCC tissues compared with adjacent non-HCC tissues and were associated with poor differentiation and early recurrence. SPL as well as SKs may be therapeutic targets for HCC treatment. PMID:26886371

  5. Fluid shear stress modulates cell migration induced by sphingosine 1-phosphate and vascular endothelial growth factor.

    PubMed

    Hughes, Shannon K; Wacker, Bradley K; Kaneda, Megan M; Elbert, Donald L

    2005-08-01

    The rational design of drug delivery systems requires the ability to predict the environment-specific responses of target cells to the delivered drug. Here we describe the in vitro effects of fluid shear stress, vascular endothelial growth factor (VEGF), and sphingosine 1-phosphate (S1P) on the migration of human umbilical vein endothelial cells (HUVEC). Endothelial cell migration into a scrape wound was enhanced in S1P- or VEGF-stimulated HUVEC by the addition of fluid shear stress. In both cases, scrape wound closure rates were near a maximal value that was not exceeded when cells were exposed to all three factors. We also found that cell migration into a scrape wound due to S1P stimulation was correlated with the S1P1 mRNA concentration, in systems where cell migration was not already near maximal. The present work represents our initial steps toward predicting cell migration based upon the activation state of the receptors and enzymes involved in the chemokinetic response. These results also illustrate the importance of context-dependent analysis of cell signaling cascades.

  6. Sphingosine-1-phosphate in inflammatory bowel disease and colitis-associated colon cancer: the fat’s in the fire

    PubMed Central

    Suh, Jung H.; Saba, Julie D.

    2015-01-01

    Colitis-associated colon cancer (CAC) is a pathological condition defined by the development of colon cancer in patients afflicted by Crohn’s disease (CD) or ulcerative colitis (UC), two idiopathic diseases of the gut which together comprise the disease group called inflammatory bowel disease (IBD). When IBD involves the colon, affected patients face an increased risk of developing colon cancer compared to the general population. The phenomenon of CAC represents one of the most convincing forms of evidence linking the processes of inflammation, oxidative stress and carcinogenesis. A greater understanding of the molecular events driving CAC could reveal new strategies to treat IBD and reduce the incidence of CAC. Sphingosine-1-phosphate (S1P) is a bioactive lipid produced through degradation of endogenous and dietary mammalian sphingolipids containing the long chain base sphingosine. S1P signals through a family of five G protein-coupled receptors. In addition, it activates nuclear factor kappa B (NF-κB) and signal transducer and activator of transcription 3 (STAT3), two transcriptional regulators that serve as master switches in inflammation and carcinogenesis. Through these and other mechanisms, a causal role for S1P in inflammatory conditions including colitis and CAC has been implicated. In contrast to S1P, dietary sphingolipids called sphingadienes derived from plant food sources cannot be converted to S1P and exhibit anti-inflammatory and chemopreventive activities, reducing colitis and CAC in mouse models. In this review, we summarize recent findings implicating S1P signaling and metabolism in the pathogenesis of IBD and CAC. The potential role of oxidative stress in modulating S1P is also discussed. Further, we propose the hypothesis that dietary sphingolipids may promote or prevent CAC depending on their ability to be converted to S1P. PMID:27011900

  7. Benzyl butyl phthalate promotes breast cancer stem cell expansion via SPHK1/S1P/S1PR3 signaling.

    PubMed

    Wang, Yu-Chih; Tsai, Cheng-Fang; Chuang, Hsiao-Li; Chang, Yi-Chih; Chen, Hung-Sheng; Lee, Jau-Nan; Tsai, Eing-Mei

    2016-05-17

    Understanding the regulatory mechanisms unique to breast cancer stem cells (BCSCs) is required to control breast cancer metastasis. We found that phthalates promote BCSCs in human breast cancer cell cultures and xenograft tumors. A toxic phthalate, benzyl butyl phthalate (BBP), activated aryl hydrocarbon receptor in breast cancer cells to stimulate sphingosine kinase 1 (SPHK1)/sphingosine 1-phosphate (S1P)/sphingosine-1-phosphate receptor 3 (S1PR3) signaling and enhance formation of metastasis-initiating BCSCs. BBP induced histone modifications in S1PR3 in side population (SP) cells, but not in non-SP cells. SPHK1 or S1PR3 knockdown in breast cancer cells effectively reduced tumor growth and lung metastasis in vivo. Our findings suggest S1PR3 is a determinant of phthalate-driven breast cancer metastasis and a possible therapeutic target for regulating BCSC populations. Furthermore, the association between breast carcinogenesis and environmental pollutants has important implications for public health. PMID:27129165

  8. Benzyl butyl phthalate promotes breast cancer stem cell expansion via SPHK1/S1P/S1PR3 signaling

    PubMed Central

    Chuang, Hsiao-Li; Chang, Yi-Chih; Chen, Hung-Sheng; Lee, Jau-Nan; Tsai, Eing-Mei

    2016-01-01

    Understanding the regulatory mechanisms unique to breast cancer stem cells (BCSCs) is required to control breast cancer metastasis. We found that phthalates promote BCSCs in human breast cancer cell cultures and xenograft tumors. A toxic phthalate, benzyl butyl phthalate (BBP), activated aryl hydrocarbon receptor in breast cancer cells to stimulate sphingosine kinase 1 (SPHK1)/sphingosine 1-phosphate (S1P)/sphingosine-1-phosphate receptor 3 (S1PR3) signaling and enhance formation of metastasis-initiating BCSCs. BBP induced histone modifications in S1PR3 in side population (SP) cells, but not in non-SP cells. SPHK1 or S1PR3 knockdown in breast cancer cells effectively reduced tumor growth and lung metastasis in vivo. Our findings suggest S1PR3 is a determinant of phthalate-driven breast cancer metastasis and a possible therapeutic target for regulating BCSC populations. Furthermore, the association between breast carcinogenesis and environmental pollutants has important implications for public health. PMID:27129165

  9. S1P lyase regulates DNA damage responses through a novel sphingolipid feedback mechanism.

    PubMed

    Kumar, A; Oskouian, B; Fyrst, H; Zhang, M; Paris, F; Saba, J D

    2011-01-01

    The injurious consequences of ionizing radiation (IR) to normal human cells and the acquired radioresistance of cancer cells represent limitations to cancer radiotherapy. IR induces DNA damage response pathways that orchestrate cell cycle arrest, DNA repair or apoptosis such that irradiated cells are either repaired or eliminated. Concomitantly and independent of DNA damage, IR activates acid sphingomyelinase (ASMase), which generates ceramide, thereby promoting radiation-induced apoptosis. However, ceramide can also be metabolized to sphingosine-1-phosphate (S1P), which acts paradoxically as a radioprotectant. Thus, sphingolipid metabolism represents a radiosensitivity pivot point, a notion supported by genetic evidence in IR-resistant cancer cells. S1P lyase (SPL) catalyzes the irreversible degradation of S1P in the final step of sphingolipid metabolism. We show that SPL modulates the kinetics of DNA repair, speed of recovery from G2 cell cycle arrest and the extent of apoptosis after IR. SPL acts through a novel feedback mechanism that amplifies stress-induced ceramide accumulation, and downregulation/inhibition of either SPL or ASMase prevents premature cell cycle progression and mitotic death. Further, oral administration of an SPL inhibitor to mice prolonged their survival after exposure to a lethal dose of total body IR. Our findings reveal SPL to be a regulator of ASMase, the G2 checkpoint and DNA repair and a novel target for radioprotection.

  10. Exogenous ceramide-1-phosphate (C1P) and phospho-ceramide analogue-1 (PCERA-1) regulate key macrophage activities via distinct receptors

    PubMed Central

    Katz, Sebastián; Ernst, Orna; Avni, Dorit; Athamna, Muhammad; Philosoph, Amir; Arana, Lide; Ouro, Alberto; Hoeferlin, L. Alexis; Meijler, Michael M.; Chalfant, Charles E.; Gómez-Muñoz, Antonio; Zor, Tsaffrir

    2016-01-01

    Inflammation is an ensemble of tightly regulated steps, in which macrophages play an essential role. Previous reports showed that the natural sphingolipid ceramide 1-phosphate (C1P) stimulates macrophages migration, while the synthetic C1P mimic, phospho-ceramide analogue-1 (PCERA-1), suppresses production of the key pro-inflammatory cytokine TNFα and amplifies production of the key anti-inflammatory cytokine IL-10 in LPS-stimulated macrophages, via one or more unidentified G-protein coupled receptors. We show that C1P stimulated RAW264.7 macrophages migration via the NFκB pathway and MCP-1 induction, while PCERA-1 neither mimicked nor antagonized these activities. Conversely, PCERA-1 synergistically elevated LPS-dependent IL-10 expression in RAW264.7 macrophages via the cAMP-PKA-CREB signaling pathway, while C1P neither mimicked nor antagonized these activities. Interestingly, both compounds have the capacity to additively inhibit TNFα secretion; PCERA-1, but not C1P, suppressed LPS-induced TNFα expression in macrophages in a CREB-dependent manner, while C1P, but not PCERA-1, directly inhibited recombinant TNFα converting enzyme (TACE). Finally, PCERA-1 failed to interfere with binding of C1P to either the cell surface receptor or to TACE. These results thus indicate that the natural sphingolipid C1P and its synthetic analog PCERA-1 bind and activate distinct receptors expressed in RAW264.7 macrophages. Identification of these receptors will be instrumental for elucidation of novel activities of extra-cellular sphingolipids, and may pave the way for the design of new sphingolipid mimics for the treatment of inflammatory diseases, and pathologies which depend on cell migration, as in metastatic tumors. PMID:26656944

  11. A novel approach for measuring sphingosine-1-phosphate and lysophosphatidic acid binding to carrier proteins using monoclonal antibodies and the Kinetic Exclusion Assay.

    PubMed

    Fleming, Jonathan K; Glass, Thomas R; Lackie, Steve J; Wojciak, Jonathan M

    2016-09-01

    Sphingosine-1-phosphate (S1P) and lysophosphatidic acid (LPA) are bioactive signaling lysophospholipids that activate specific G protein-coupled receptors on the cell surface triggering numerous biological events. In circulation, S1P and LPA associate with specific carrier proteins or chaperones; serum albumin binds both S1P and LPA while HDL shuttles S1P via interactions with apoM. We used a series of kinetic exclusion assays in which monoclonal anti-S1P and anti-LPA antibodies competed with carrier protein for the lysophospholipid to measure the equilibrium dissociation constants (Kd) for these carrier proteins binding S1P and the major LPA species. Fatty acid-free (FAF)-BSA binds these lysophospholipids with the following Kd values: LPA(16:0), 68 nM; LPA(18:1), 130 nM; LPA(18:2), 350 nM; LPA(20:4), 2.2 μM; and S1P, 41 μM. FAF human serum albumin binds each lysophospholipid with comparable affinities. By measuring the apoM concentration and expanding the model to include endogenous ligand, we were able to resolve the Kd values for S1P binding apoM in the context of human HDL and LDL particles (21 nM and 2.4 nM, respectively). The novel competitive assay and analysis described herein enables measurement of Kd values of completely unmodified lysophospholipids binding unmodified carrier proteins in solution, and thus provide insights into S1P and LPA storage in the circulation system and may be useful in understanding chaperone-dependent receptor activation and signaling. PMID:27444045

  12. The Adipose Mesenchymal Stem Cell Secretome Inhibits Inflammatory Responses of Microglia: Evidence for an Involvement of Sphingosine-1-Phosphate Signalling.

    PubMed

    Marfia, Giovanni; Navone, Stefania Elena; Hadi, Loubna Abdel; Paroni, Moira; Berno, Valeria; Beretta, Matteo; Gualtierotti, Roberta; Ingegnoli, Francesca; Levi, Vincenzo; Miozzo, Monica; Geginat, Jens; Fassina, Lorenzo; Rampini, Paolo; Tremolada, Carlo; Riboni, Laura; Campanella, Rolando

    2016-07-15

    Central nervous system (CNS) inflammation is primarily driven by microglial cells which secrete proinflammatory cytokines and undergo proliferation upon activation, as it occurs in neurodegenerative diseases. Uncontrolled or prolonged CNS inflammation is potentially harmful and can result in cellular damage. Recently, many studies have focused on human adipose tissue as an attractive source of cytokines with immunosuppressive properties that potentially modulate inflammation. Our study aimed to evaluate if different methods of human tissue collection could affect adipose mesenchymal stem cell (ADSC)-derived cytokine secretion and investigate the effects of ADSC secretome in modulating microglia activation and the possible implication of sphingosine-1-phosphate (S1P) in these effects. Our results demonstrate that the conditioned medium (CM) of ADSCs isolated by two different processing methods (lipoaspirate and Lipogems) significantly inhibited the lipopolysaccharide (LPS)-induced effects on microglia activation, including microglial expression of CD68, cytokine secretion, proliferation, and migration. Pulse studies with radiolabeled sphingosine demonstrated that LPS treatment of resting microglia induced a significant increase of both cellular and extracellular S1P. Moreover, and of relevance, FTY720, a functional antagonist of S1P receptor, inhibited the multiple LPS-induced proinflammatory effects on microglia, and S1P suppressed the anti-inflammatory effect of ADSC-CM. This suggests that LPS-mediated microglial activation is countered by ADSC-CM through the modulation of sphingosine kinase/S1P signalling. PMID:27217090

  13. Antiapoptotic Agent Sphingosine-1-Phosphate Protects Vitrified Murine Ovarian Grafts

    PubMed Central

    Tsai, Yung-Chieh; Tzeng, Chii-Ruey; Wang, Chia-Woei; Hsu, Ming-I; Tan, Shun-Jen

    2014-01-01

    Significant follicle loss from frozen ovarian grafts is unavoidable. The authors evaluated the protective effects of the antiapoptotic agent sphingosine-1-phosphate (S1P) on vitrified ovarian grafts. Three-week-old sexually immature female FVB mice were divided into 4 groups, fresh, control without S1P, 0.5 mmol/L S1P, and 2 mmol/L S1P. The ovaries were pretreated with S1P for 1 hour and then cryopreserved by modified vitrification. The frozen–thawed ovaries were autotransplanted under the back muscles of mice for 10 days. Expression of apoptosis-related genes encoding caspase 3 and c-Myc was analyzed in the vitrified ovaries and 10 days after transplantation using real-time quantitative polymerase chain reaction. To quantify the ovarian reserve, anti-Müllerian hormone (AMH) levels and follicles were measured in the 10-day vitrified ovarian grafts. Caspase 3 and c-Myc messenger RNA did not differ significantly in the 4 groups after vitrification but was significantly upregulated in the control group after transplantation. The AMH levels and primordial follicle pool were significantly higher in the S1P-treated groups than in the control group but lower than that in the fresh group. The S1P protects vitrified ovarian grafts from ischemic reperfusion injury rather than from vitrification-associated process. PMID:23793475

  14. Sphingosine 1-phosphate induced synthesis of glycocalyx on endothelial cells.

    PubMed

    Zeng, Ye; Liu, Xiao-Heng; Tarbell, John; Fu, Bingmei

    2015-11-15

    Sphingosine 1-phosphate (S1P) protects glycocalyx against shedding, playing important roles in endothelial functions. We previously found that glycocalyx on endothelial cells (ECs) was shed after plasma protein depletion. In the present study, we investigated the role of S1P on the recovery of glycocalyx, and tested whether it is mediated by phosphoinositide 3-kinase (PI3K) pathway. After depletion of plasma protein, ECs were treated with S1P for another 6h. And then, the major components of glycocalyx including syndecan-1 with attached heparan sulfate (HS) and chondroitin sulfate (CS) on endothelial cells were detected using confocal fluorescence microscopy. Role of PI3K in the S1P-induced synthesis of glycocalyx was confirmed by using the PI3K inhibitor (LY294002). Syndecan-1 with attached HS and CS were degraded with duration of plasma protein depletion. S1P induced recovery of syndecan-1 with attached HS and CS. The PI3K inhibitor LY294002 abolished the effect of S1P on recovery of glycocalyx. Thus, S1P induced synthesis of glycocalyx on endothelial cells and it is mediated by PI3K pathway.

  15. CTGF/CCN2 exerts profibrotic action in myoblasts via the up-regulation of sphingosine kinase-1/S1P3 signaling axis: Implications in the action mechanism of TGFβ.

    PubMed

    Bruno, Gennaro; Cencetti, Francesca; Pertici, Irene; Japtok, Lukasz; Bernacchioni, Caterina; Donati, Chiara; Bruni, Paola

    2015-02-01

    The matricellular protein connective tissue growth factor (CTGF/CCN2) is recognized as key player in the onset of fibrosis in various tissues, including skeletal muscle. In many circumstances, CTGF has been shown to be induced by transforming growth factor beta (TGFβ) and accounting, at least in part, for its biological action. In this study it was verified that in cultured myoblasts CTGF/CCN2 causes their transdifferentiation into myofibroblasts by up-regulating the expression of fibrosis marker proteins α-smooth muscle actin and transgelin. Interestingly, it was also found that the profibrotic effect exerted by CTGF/CCN2 was mediated by the sphingosine kinase (SK)-1/S1P3 signaling axis specifically induced by the treatment with the profibrotic cue. Following CTGF/CCN2-induced up-regulation, S1P3 became the S1P receptor subtype expressed at the highest degree, at least at mRNA level, and was thus capable of readdressing the sphingosine 1-phosphate signaling towards fibrosis rather than myogenic differentiation. Another interesting finding is that CTGF/CCN2 silencing prevented the TGFβ-dependent up-regulation of SK1/S1P3 signaling axis and strongly reduced the profibrotic effect exerted by TGFβ, pointing at a crucial role of endogenous CTGF/CCN2 generated following TGFβ challenge in the transmission of at least part of its profibrotic effect. These results provide new insights into the molecular mechanism by which CTGF/CCN2 drives its biological action and strengthen the concept that SK1/S1P3 axis plays a critical role in the onset of fibrotic cell phenotype.

  16. Crystal Structure of a Lipid G Protein-Coupled Receptor

    SciTech Connect

    Hanson, Michael A; Roth, Christopher B; Jo, Euijung; Griffith, Mark T; Scott, Fiona L; Reinhart, Greg; Desale, Hans; Clemons, Bryan; Cahalan, Stuart M; Schuerer, Stephan C; Sanna, M Germana; Han, Gye Won; Kuhn, Peter; Rosen, Hugh; Stevens, Raymond C

    2012-03-01

    The lyso-phospholipid sphingosine 1-phosphate modulates lymphocyte trafficking, endothelial development and integrity, heart rate, and vascular tone and maturation by activating G protein-coupled sphingosine 1-phosphate receptors. Here, we present the crystal structure of the sphingosine 1-phosphate receptor 1 fused to T4-lysozyme (S1P1-T4L) in complex with an antagonist sphingolipid mimic. Extracellular access to the binding pocket is occluded by the amino terminus and extracellular loops of the receptor. Access is gained by ligands entering laterally between helices I and VII within the transmembrane region of the receptor. This structure, along with mutagenesis, agonist structure-activity relationship data, and modeling, provides a detailed view of the molecular recognition and requirement for hydrophobic volume that activates S1P1, resulting in the modulation of immune and stromal cell responses.

  17. Role of sphingolipids in murine radiation-induced lung injury: protection by sphingosine 1-phosphate analogs

    PubMed Central

    Mathew, Biji; Jacobson, Jeffrey R.; Berdyshev, Evgeny; Huang, Yong; Sun, Xiaoguang; Zhao, Yutong; Gerhold, Lynnette M.; Siegler, Jessica; Evenoski, Carrie; Wang, Ting; Zhou, Tong; Zaidi, Rafe; Moreno-Vinasco, Liliana; Bittman, Robert; Chen, Chin Tu; LaRiviere, Patrick J.; Sammani, Saad; Lussier, Yves A.; Dudek, Steven M.; Natarajan, Viswanathan; Weichselbaum, Ralph R.; Garcia, Joe G. N.

    2011-01-01

    Clinically significant radiation-induced lung injury (RILI) is a common toxicity in patients administered thoracic radiotherapy. Although the molecular etiology is poorly understood, we previously characterized a murine model of RILI in which alterations in lung barrier integrity surfaced as a potentially important pathobiological event and genome-wide lung gene mRNA levels identified dysregulation of sphingolipid metabolic pathway genes. We hypothesized that sphingolipid signaling components serve as modulators and novel therapeutic targets of RILI. Sphingolipid involvement in murine RILI was confirmed by radiation-induced increases in lung expression of sphingosine kinase (SphK) isoforms 1 and 2 and increases in the ratio of ceramide to sphingosine 1-phosphate (S1P) and dihydro-S1P (DHS1P) levels in plasma, bronchoalveolar lavage fluid, and lung tissue. Mice with a targeted deletion of SphK1 (SphK1−/−) or with reduced expression of S1P receptors (S1PR1+/−, S1PR2−/−, and S1PR3−/−) exhibited marked RILI susceptibility. Finally, studies of 3 potent vascular barrier-protective S1P analogs, FTY720, (S)-FTY720-phosphonate (fTyS), and SEW-2871, identified significant RILI attenuation and radiation-induced gene dysregulation by the phosphonate analog, fTyS (0.1 and 1 mg/kg i.p., 2×/wk) and to a lesser degree by SEW-2871 (1 mg/kg i.p., 2×/wk), compared with those in controls. These results support the targeting of S1P signaling as a novel therapeutic strategy in RILI.—Mathew, B., Jacobson, J. R., Berdyshev, E., Huang, Y., Sun, X., Zhao, Y., Gerhold, L. M., Siegler, J., Evenoski, C., Wang, T., Zhou, T., Zaidi, R., Moreno-Vinasco, L., Bittman, R., Chen, C. T., LaRiviere, P. J., Sammani, S., Lussier, Y. A., Dudek, S. M., Natarajan, V., Weichselbaum, R. R., Garcia, J. G. N. Role of sphingolipids in murine radiation-induced lung injury: protection by sphingosine 1-phosphate analogs. PMID:21712494

  18. A Potent and Selective C-11 Labeled PET Tracer for Imaging Sphingosine-1-phosphate Receptor 2 in the CNS Demonstrates Sexually Dimorphic Expression

    PubMed Central

    Yue, Xuyi; Jin, Hongjun; Liu, Hui; Rosenberg, Adam J.; Klein, Robyn S.; Tu, Zhude

    2015-01-01

    Sphingosine-1-phosphate receptor 2 (S1PR2) plays an essential role in regulating blood-brain barrier (BBB) function during demyelinating central nervous system (CNS) disease. Increased expression of S1PR2 occurs in disease-susceptible CNS regions of female versus male SJL mice and in female multiple sclerosis (MS) patients. Here we reported a novel sensitive and noninvasive method to quantitatively assess S1PR2 expression using a C-1l labeled positron emission tomography (PET) radioligand [11C]5a for in vivo imaging of S1PR2. Compounds 5a exhibited promising binding potency with IC50 value of 9.52 ± 0.70 nM for S1PR2 and high selectivity over S1PR1 and S1PR3 (both IC50 > 1000 nM). [11C]5a was synthesized in ~40 min withradiochemistry yield of 20 ± 5% (decayed to the end of bombardment (EOB), n > 10), specific activity of 6 – 10 Ci/μmol (decayed to EOB). The biodistribution study in female SJL mice showed the cerebellar uptake of radioactivity at 30 min of post-injection of [11C]5a was increased by Cyclosporin A (CsA) pretreatment (from 0.84 ± 0.04 ID%/g to 2.21 ± 0.21 ID%/g, n = 4, p < 0.01). MicroPET data revealed that naive female SJL mice exhibited higher cerebellar uptake compared with males following CsA pretreatment (standardized uptake values (SUV) 0.58 ± 0.16 vs 0.48 ± 0.12 at 30 min of post-injection, n = 4, p < 0.05), which was consistent with the autoradiographic results. These data suggested that [11C]5a has the capability in assessing the sexual dimorphism of S1PR2 expression in the cerebellum of the SJL mice. The development of radioligands for S1PR2 to identify a clinical suitable S1PR2 PET radiotracer, may greatly contribute to investigating sex differences in S1PR2 expression that contribute to MS subtype and disease progression and it will be very useful for detecting MS in early state and differentiating MS with other patients with neuroinflammatory diseases, and monitoring the efficacy of treating diseases using S1PR2 antagonism. PMID

  19. Pseudomonas-derived ceramidase induces production of inflammatory mediators from human keratinocytes via sphingosine-1-phosphate.

    PubMed

    Oizumi, Ami; Nakayama, Hitoshi; Okino, Nozomu; Iwahara, Chihiro; Kina, Katsunari; Matsumoto, Ryo; Ogawa, Hideoki; Takamori, Kenji; Ito, Makoto; Suga, Yasushi; Iwabuchi, Kazuhisa

    2014-01-01

    Ceramide is important for water retention and permeability barrier functions in the stratum corneum, and plays a key role in the pathogenesis of atopic dermatitis (AD). A Pseudomonas aeruginosa-derived neutral ceramidase (PaCDase) isolated from a patient with AD was shown to effectively degrade ceramide in the presence of Staphylococcus aureus-derived lipids or neutral detergents. However, the effect of ceramide metabolites on the functions of differentiating keratinocytes is poorly understood. We found that the ceramide metabolite sphingosine-1-phosphate (S1P) stimulated the production of inflammatory mediators such as TNF-α and IL-8 from three-dimensionally cultured human primary keratinocytes (termed "3D keratinocytes"), which form a stratum corneum. PaCDase alone did not affect TNF-α gene expression in 3D keratinocytes. In the presence of the detergent Triton X-100, which damages stratum corneum structure, PaCDase, but not heat-inactivated PaCDase or PaCDase-inactive mutant, induced the production of TNF-α, endothelin-1, and IL-8, indicating that this production was dependent on ceramidase activity. Among various ceramide metabolites, sphingosine and S1P enhanced the gene expression of TNF-α, endothelin-1, and IL-8. The PaCDase-enhanced expression of these genes was inhibited by a sphingosine kinase inhibitor and by an S1P receptor antagonist VPC 23019. The TNF-α-binding antibody infliximab suppressed the PaCDase-induced upregulation of IL-8, but not TNF-α, mRNA. PaCDase induced NF-κB p65 phosphorylation. The NF-κB inhibitor curcumin significantly inhibited PaCDase-induced expression of IL-8 and endothelin-1. VPC 23019 and infliximab inhibited PaCDase-induced NF-κB p65 phosphorylation and reduction in the protein level of the NF-κB inhibitor IκBα. Collectively, these findings suggest that (i) 3D keratinocytes produce S1P from sphingosine, which is produced through the hydrolysis of ceramide by PaCDase, (ii) S1P induces the production of TNF-α via S

  20. Circulating levels of sphingosine-1-phosphate are elevated in severe, but not mild psoriasis and are unresponsive to anti-TNF-α treatment

    NASA Astrophysics Data System (ADS)

    Checa, Antonio; Xu, Ning; Sar, Daniel G.; Haeggström, Jesper Z.; Ståhle, Mona; Wheelock, Craig E.

    2015-07-01

    Sphingolipids are bioactive molecules with a putative role in inflammation. Alterations in sphingolipids, in particular ceramides, have been consistently observed in psoriatic skin. Herein, we quantified the circulating sphingolipid profile in individuals with mild or severe psoriasis as well as healthy controls. In addition, the effects of anti-TNF-α treatment were determined. Levels of sphingoid bases, including sphingosine-1-phosphate (S1P), increased in severe (P < 0.001 n = 32), but not in mild (n = 32), psoriasis relative to healthy controls (n = 32). These alterations were not reversed in severe patients (n = 16) after anti-TNF-α treatment despite significant improvement in psoriasis lesions. Circulating levels of sphingomyelins and ceramides shifted in a fatty acid chain length-dependent manner. These alterations were also observed in psoriasis skin lesions and were associated with changes in mRNA levels of ceramide synthases. The lack of S1P response to treatment may have pathobiological implications due to its close relation to the vascular and immune systems. In particular, increased levels of sphingolipids and especially S1P in severe psoriasis patients requiring biological treatment may potentially be associated with cardiovascular comorbidities. The fact that shifts in S1P levels were not ameliorated by anti-TNF-α treatment, despite improvements in the skin lesions, further supports targeting S1P receptors as therapy for severe psoriasis.

  1. Circulating levels of sphingosine-1-phosphate are elevated in severe, but not mild psoriasis and are unresponsive to anti-TNF-α treatment

    PubMed Central

    Checa, Antonio; Xu, Ning; Sar, Daniel G.; Haeggström, Jesper Z.; Ståhle, Mona; Wheelock, Craig E.

    2015-01-01

    Sphingolipids are bioactive molecules with a putative role in inflammation. Alterations in sphingolipids, in particular ceramides, have been consistently observed in psoriatic skin. Herein, we quantified the circulating sphingolipid profile in individuals with mild or severe psoriasis as well as healthy controls. In addition, the effects of anti-TNF-α treatment were determined. Levels of sphingoid bases, including sphingosine-1-phosphate (S1P), increased in severe (P < 0.001; n = 32), but not in mild (n = 32), psoriasis relative to healthy controls (n = 32). These alterations were not reversed in severe patients (n = 16) after anti-TNF-α treatment despite significant improvement in psoriasis lesions. Circulating levels of sphingomyelins and ceramides shifted in a fatty acid chain length-dependent manner. These alterations were also observed in psoriasis skin lesions and were associated with changes in mRNA levels of ceramide synthases. The lack of S1P response to treatment may have pathobiological implications due to its close relation to the vascular and immune systems. In particular, increased levels of sphingolipids and especially S1P in severe psoriasis patients requiring biological treatment may potentially be associated with cardiovascular comorbidities. The fact that shifts in S1P levels were not ameliorated by anti-TNF-α treatment, despite improvements in the skin lesions, further supports targeting S1P receptors as therapy for severe psoriasis. PMID:26174087

  2. Sphingosine 1-Phosphate-Induced ICAM-1 Expression via NADPH Oxidase/ROS-Dependent NF-κB Cascade on Human Pulmonary Alveolar Epithelial Cells

    PubMed Central

    Lin, Chih-Chung; Yang, Chien-Chung; Cho, Rou-Ling; Wang, Chen-Yu; Hsiao, Li-Der; Yang, Chuen-Mao

    2016-01-01

    The intercellular adhesion molecule-1 (ICAM-1) expression is frequently correlated with the lung inflammation. In lung injury, sphingosine-1-phosphate (S1P, bioactive sphingolipid metabolite), participate gene regulation of adhesion molecule in inflammation progression and aggravate tissue damage. To investigate the transduction mechanisms of the S1P in pulmonary epithelium, we demonstrated that exposure of HPAEpiCs (human pulmonary alveolar epithelial cells) to S1P significantly induces ICAM-1 expression leading to increase monocyte adhesion on the surface of HPAEpiCs. These phenomena were effectively attenuated by pretreatments with series of inhibitors such as Rottlerin (PKCδ), PF431396 (PYK2), diphenyleneiodonium chloride (DPI), apocynin (NADPH oxidase), Edaravone (ROS), and Bay11-7082 (NF-κB). Consistently, knockdown with siRNA transfection of PKCδ, PYK2, p47phox, and p65 exhibited the same results. Pretreatment with both Gq-coupled receptor antagonist (GPA2A) and Gi/o-coupled receptor antagonist (GPA2) also blocked the upregulation of ICAM-1 protein and mRNA induced by S1P. We observed that S1P induced PYK2 activation via a Gq-coupled receptor/PKCδ-dependent pathway. In addition, S1P induced NADPH oxidase activation and intracellular ROS generation, which were also reduced by Rottlerin or PF431396. We demonstrated that S1P induced NF-κB p65 phosphorylation and nuclear translocation in HPAEpiCs. Activated NF-κB was blocked by Rottlerin, PF431396, APO, DPI, or Edaravone. Besides, the results of monocyte adhesion assay indicated that S1P-induced ICAM-1 expression on HPAEpiCs can enhance the monocyte attachments. In the S1P-treated mice, we found that the levels of ICAM-1 protein and mRNA in the lung fractions, the pulmonary hematoma and leukocyte count in bronchoalveolar lavage fluid were enhanced through a PKCδ/PYK2/NADPH oxidase/ROS/NF-κB signaling pathway. We concluded that S1P-accelerated lung damage is due to the ICAM-1 induction associated with

  3. Sphingosine-1-phosphate metabolism: A structural perspective.

    PubMed

    Pulkoski-Gross, Michael J; Donaldson, Jane C; Obeid, Lina M

    2015-01-01

    Sphingolipids represent an important class of bioactive signaling lipids which have key roles in numerous cellular processes. Over the last few decades, the levels of bioactive sphingolipids and/or their metabolizing enzymes have been realized to be important factors involved in disease development and progression, most notably in cancer. Targeting sphingolipid-metabolizing enzymes in disease states has been the focus of many studies and has resulted in a number of pharmacological inhibitors, with some making it into the clinic as therapeutics. In order to better understand the regulation of sphingolipid-metabolizing enzymes as well as to develop much more potent and specific inhibitors, the field of sphingolipids has recently taken a turn toward structural biology. The last decade has seen the structural determination of a number of sphingolipid enzymes and effector proteins. In these terms, one of the most complete arms of the sphingolipid pathway is the sphingosine-1-phosphate (S1P) arm. The structures of proteins involved in the function and regulation of S1P are being used to investigate further the regulation of said proteins as well as in the design and development of inhibitors as potential therapeutics.

  4. Neurons and Oligodendrocytes Recycle Sphingosine 1-Phosphate to Ceramide

    PubMed Central

    Qin, Jingdong; Berdyshev, Evgeny; Goya, Jonathan; Natarajan, Viswanathan; Dawson, Glyn

    2010-01-01

    Both cultured neonatal rat hippocampal neurons and differentiated oligodendrocytes rapidly metabolized exogenous C2- and C6-ceramides to sphingosine (Sph) and sphingosine 1-phosphate (S1P) but only minimally to C16–24-ceramides. Dihydrosphinolipids were unaffected but were increased by exogenous C6-dihydroceramide. Conversely, quantitative liquid chromatography-tandem mass spectrometry technology showed that exogenous S1P (0.25–10 μm) was rapidly metabolized to both Sph (a >200-fold increase) and predominantly C18-ceramide (a >2-fold increase). Longer treatments with either C2-ceramide (>2.5 μm) or S1P (10 μm) led to apoptotic cell death. Thus, there is an active sphingolipid salvage pathway in both neurons and oligodendrocytes. Staurosporine-induced cell death was shown to be associated with decreased S1P and increased Sph and C16/18-ceramide levels. The physiological significance of this observation was confirmed by the analysis of affected white matter and plaques from brains of multiple sclerosis patients in which reduced S1P and increased Sph and C16/18-ceramides were observed. PMID:20215115

  5. Resveratrol stimulates sphingosine-1-phosphate signaling of cathelicidin production.

    PubMed

    Park, Kyungho; Elias, Peter M; Hupe, Melanie; Borkowski, Andrew W; Gallo, Richard L; Shin, Kyong-Oh; Lee, Yong-Moon; Holleran, Walter M; Uchida, Yoshikazu

    2013-08-01

    We recently discovered a regulatory mechanism that stimulates the production of the multifunctional antimicrobial peptide cathelicidin antimicrobial peptide (CAMP). In response to subtoxic levels of ER stress, increased sphingosine-1-phosphate (S1P) production activates an NFκBC/EBPα-dependent pathway that enhances CAMP production in cultured human keratinocytes. As the multifunctional stilbenoid compound resveratrol (RESV) increases ceramide (Cer) levels, a precursor of S1P, we hypothesized and assessed whether RESV could exploit the same pathway to regulate CAMP production. Accordingly, RESV significantly increased Cer and S1P levels in cultured keratinocytes, paralleled by increased CAMP mRNA/protein expression. Furthermore, topical RESV also increased murine CAMP mRNA/protein expression in mouse skin. Conversely, blockade of Cer-->sphingosine-->S1P metabolic conversion, with specific inhibitors of ceramidase or sphingosine kinase, attenuated the expected RESV-mediated increase in CAMP expression. The RESV-induced increase in CAMP expression required both NF-κB and C/EBPα transactivation. Moreover, conditioned media from keratinocytes treated with RESV significantly suppressed Staphylococcus aureus growth. Finally, topical RESV, if not coapplied with a specific inhibitor of sphingosine kinase, blocked S. aureus invasion into murine skin. These results demonstrate that the dietary stilbenoid RESV stimulates S1P signaling of CAMP production through an NF-κB-->C/EBPα-dependent mechanism, leading to enhanced antimicrobial defense against exogenous microbial pathogens. PMID:23856934

  6. Cytoplasmic sphingosine-1-phosphate pathway modulates neuronal autophagy

    PubMed Central

    Moruno Manchon, Jose Felix; Uzor, Ndidi-Ese; Dabaghian, Yuri; Furr-Stimming, Erin E.; Finkbeiner, Steven; Tsvetkov, Andrey S.

    2015-01-01

    Autophagy is an important homeostatic mechanism that eliminates long-lived proteins, protein aggregates and damaged organelles. Its dysregulation is involved in many neurodegenerative disorders. Autophagy is therefore a promising target for blunting neurodegeneration. We searched for novel autophagic pathways in primary neurons and identified the cytosolic sphingosine-1-phosphate (S1P) pathway as a regulator of neuronal autophagy. S1P, a bioactive lipid generated by sphingosine kinase 1 (SK1) in the cytoplasm, is implicated in cell survival. We found that SK1 enhances flux through autophagy and that S1P-metabolizing enzymes decrease this flux. When autophagy is stimulated, SK1 relocalizes to endosomes/autophagosomes in neurons. Expression of a dominant-negative form of SK1 inhibits autophagosome synthesis. In a neuron model of Huntington’s disease, pharmacologically inhibiting S1P-lyase protected neurons from mutant huntingtin-induced neurotoxicity. These results identify the S1P pathway as a novel regulator of neuronal autophagy and provide a new target for developing therapies for neurodegenerative disorders. PMID:26477494

  7. Resveratrol Stimulates Sphingosine-1-Phosphate Signaling of Cathelicidin Production

    PubMed Central

    Park, Kyungho; Elias, Peter M.; Hupe, Melanie; Borkowski, Andrew W.; Gallo, Richard L.; Shin, Kyong-Oh; Lee, Yong-Moon; Holleran, Walter M.; Uchida, Yoshikazu

    2013-01-01

    We recently discovered a regulatory mechanism that stimulates production of the multifunctional antimicrobial peptide, cathelicidin antimicrobial peptide (CAMP). In response to subtoxic levels of ER stress, increased sphingosine-1-phosphate (S1P) production activates an NFκB→C/EBPα dependent pathway that enhances CAMP production in cultured human keratinocytes. Since the multifunctional stilbenoid compound, resveratrol (RESV), increases ceramide (Cer) levels, a precursor of S1P, we hypothesized and assessed whether RESV could exploit the same pathway to regulate CAMP production. Accordingly, RESV significantly increased Cer and S1P levels in cultured keratinocytes, paralleled by increased CAMP mRNA/protein expression. Furthermore, topical RESV also increased murine CAMP mRNA/protein expression in mouse skin. Conversely, blockade of Cer→sphingosine→S1P metabolic conversion, with specific inhibitors of ceramidase or sphingosine kinase, attenuated the expected RESV-mediated increase in CAMP expression. The RESV-induced increase in CAMP expression required both NF-κB and C/EBPα transactivation. Moreover, conditioned media from keratinocyte treated with RESV significantly suppressed Staphylococcus aureus growth. Finally, topical RESV, if not coapplied with a specific inhibitor of sphingosine kinase, blocked Staphylococcus aureus invasion into murine skin. These results demonstrate that the dietary stilbenoid, RESV, stimulates S1P signaling of CAMP production through an NF-κB→C/EBPα-dependent mechanism, leading to enhanced antimicrobial defense against exogenous microbial pathogens. PMID:23856934

  8. Legionella pneumophila S1P-lyase targets host sphingolipid metabolism and restrains autophagy

    PubMed Central

    Rolando, Monica; Escoll, Pedro; Nora, Tamara; Botti, Joëlle; Boitez, Valérie; Daniels, Craig; Abraham, Gilu; Stogios, Peter J.; Skarina, Tatiana; Christophe, Charlotte; Dervins-Ravault, Delphine; Cazalet, Christel; Hilbi, Hubert; Rupasinghe, Thusitha W. T.; Tull, Dedreia; McConville, Malcolm J.; Ong, Sze Ying; Hartland, Elizabeth L.; Codogno, Patrice; Levade, Thierry; Naderer, Thomas; Savchenko, Alexei; Buchrieser, Carmen

    2016-01-01

    Autophagy is an essential component of innate immunity, enabling the detection and elimination of intracellular pathogens. Legionella pneumophila, an intracellular pathogen that can cause a severe pneumonia in humans, is able to modulate autophagy through the action of effector proteins that are translocated into the host cell by the pathogen’s Dot/Icm type IV secretion system. Many of these effectors share structural and sequence similarity with eukaryotic proteins. Indeed, phylogenetic analyses have indicated their acquisition by horizontal gene transfer from a eukaryotic host. Here we report that L. pneumophila translocates the effector protein sphingosine-1 phosphate lyase (LpSpl) to target the host sphingosine biosynthesis and to curtail autophagy. Our structural characterization of LpSpl and its comparison with human SPL reveals high structural conservation, thus supporting prior phylogenetic analysis. We show that LpSpl possesses S1P lyase activity that was abrogated by mutation of the catalytic site residues. L. pneumophila triggers the reduction of several sphingolipids critical for macrophage function in an LpSpl-dependent and -independent manner. LpSpl activity alone was sufficient to prevent an increase in sphingosine levels in infected host cells and to inhibit autophagy during macrophage infection. LpSpl was required for efficient infection of A/J mice, highlighting an important virulence role for this effector. Thus, we have uncovered a previously unidentified mechanism used by intracellular pathogens to inhibit autophagy, namely the disruption of host sphingolipid biosynthesis. PMID:26831115

  9. Legionella pneumophila S1P-lyase targets host sphingolipid metabolism and restrains autophagy.

    PubMed

    Rolando, Monica; Escoll, Pedro; Nora, Tamara; Botti, Joëlle; Boitez, Valérie; Bedia, Carmen; Daniels, Craig; Abraham, Gilu; Stogios, Peter J; Skarina, Tatiana; Christophe, Charlotte; Dervins-Ravault, Delphine; Cazalet, Christel; Hilbi, Hubert; Rupasinghe, Thusitha W T; Tull, Dedreia; McConville, Malcolm J; Ong, Sze Ying; Hartland, Elizabeth L; Codogno, Patrice; Levade, Thierry; Naderer, Thomas; Savchenko, Alexei; Buchrieser, Carmen

    2016-02-16

    Autophagy is an essential component of innate immunity, enabling the detection and elimination of intracellular pathogens. Legionella pneumophila, an intracellular pathogen that can cause a severe pneumonia in humans, is able to modulate autophagy through the action of effector proteins that are translocated into the host cell by the pathogen's Dot/Icm type IV secretion system. Many of these effectors share structural and sequence similarity with eukaryotic proteins. Indeed, phylogenetic analyses have indicated their acquisition by horizontal gene transfer from a eukaryotic host. Here we report that L. pneumophila translocates the effector protein sphingosine-1 phosphate lyase (LpSpl) to target the host sphingosine biosynthesis and to curtail autophagy. Our structural characterization of LpSpl and its comparison with human SPL reveals high structural conservation, thus supporting prior phylogenetic analysis. We show that LpSpl possesses S1P lyase activity that was abrogated by mutation of the catalytic site residues. L. pneumophila triggers the reduction of several sphingolipids critical for macrophage function in an LpSpl-dependent and -independent manner. LpSpl activity alone was sufficient to prevent an increase in sphingosine levels in infected host cells and to inhibit autophagy during macrophage infection. LpSpl was required for efficient infection of A/J mice, highlighting an important virulence role for this effector. Thus, we have uncovered a previously unidentified mechanism used by intracellular pathogens to inhibit autophagy, namely the disruption of host sphingolipid biosynthesis.

  10. Regulation of the micromechanical properties of pulmonary endothelium by S1P and thrombin: role of cortactin.

    PubMed

    Arce, Fernando Terán; Whitlock, Jenny L; Birukova, Anna A; Birukov, Konstantin G; Arnsdorf, Morton F; Lal, Ratnesh; Garcia, Joe G N; Dudek, Steven M

    2008-07-01

    Disruption of pulmonary endothelial cell (EC) barrier function is a critical pathophysiologic event in highly morbid inflammatory conditions such as sepsis and acute respiratory disease stress syndrome. Actin cytoskeleton, an essential regulator of endothelial permeability, is a dynamic structure whose stimuli-induced rearrangement is linked to barrier modulation. Here, we used atomic force microscopy to characterize structural and mechanical changes in the F-actin cytoskeleton of cultured human pulmonary artery EC in response to both barrier-enhancing (induced by sphingosine 1-phosphate (S1P)) and barrier-disrupting (induced by thrombin) conditions. Atomic force microscopy elasticity measurements show differential effects: for the barrier protecting molecule S1P, the elastic modulus was elevated significantly on the periphery; for the barrier-disrupting molecule thrombin, on the other hand, it was elevated significantly in the central region of the cell. The force and elasticity maps correlate with F-actin rearrangements as identified by immunofluorescence analysis. Significantly, reduced expression (via siRNA) of cortactin, an actin-binding protein essential to EC barrier regulation, resulted in a shift in the S1P-mediated elasticity pattern to more closely resemble control, unstimulated endothelium. PMID:18408039

  11. Scintillation Proximity Assay to Detect the Changes in Cellular Dihydrosphingosine 1-Phosphate Levels.

    PubMed

    Ohtoyo, Mamoru; Tamura, Masakazu; Machinaga, Nobuo; Muro, Fumihito; Hashimoto, Ryuji

    2016-10-01

    Compounds that modulate the activity of sphingosine 1-phosphate (S1P)-metabolizing enzymes are expected to be potential therapeutic agents for various diseases. Investigation of their potencies requires not only cell-free but also cell-based assays in which intracellular accumulation/depletion of S1P could be monitored. However, conventional methods have limitations to their simplicity, mainly due to the necessity of a separation process that separates S1P from its related substances. Here, we describe a method utilizing a scintillation proximity assay (SPA) for semi-quantifying intracellular [(3)H]-labeled dihydroS1P ([(3)H]dhS1P), which is also a substrate for S1P-metabolizing enzymes. We found that uncoated yttrium silicate SPA beads could selectively bind to and detect [(3)H]dhS1P rather than [(3)H]dihydrosphingosine (the non-phosphorylated form of [(3)H]dhS1P). Based on this, we developed a novel cell-based assay system which does not require any organic solvent extraction or chromatographic separation, and confirmed its practicality by using siRNA targeting S1P lyase (S1PL) and known S1PL inhibitors as models. Our results demonstrated that this assay is useful for rapid and easy evaluation of S1PL inhibitors, and could be potentially applicable for all compounds that modulate the activity of S1P-metabolizing enzymes. PMID:27585475

  12. Cytokine storm plays a direct role in the morbidity and mortality from influenza virus infection and is chemically treatable with a single sphingosine-1-phosphate agonist molecule.

    PubMed

    Oldstone, Michael B A; Rosen, Hugh

    2014-01-01

    Cytokine storm defines a dysregulation of and an excessively exaggerated immune response most often accompanying selected viral infections and several autoimmune diseases. Newly emerging and re-emerging infections of the respiratory tract, especially influenza, SARS, and hantavirus post considerable medical problems. Their morbidities and mortalities are often a direct result of cytokine storm. This chapter visits primarily influenza virus infection and resultant cytokine storm. It provides the compelling evidence that illuminates cytokine storm in influenza pathogenesis and the clear findings that cytokine storm is chemically tractable by therapy directed toward sphingosine-1-phosphate receptor (S1PR) modulation, specifically S1P1R agonist therapy. The mechanism(s) of how S1P1R signaling works and the pathways involved are subjects of this review.

  13. Lysophospholipid Receptors Are Differentially Expressed in Rat Terminal Schwann Cells, As Revealed by a Single Cell RT-PCR and In Situ Hybridization

    PubMed Central

    Kobashi, Hiroaki; Yaoi, Takeshi; Oda, Ryo; Okajima, Seiichiro; Fujiwara, Hiroyoshi; Kubo, Toshikazu; Fushiki, Shinji

    2006-01-01

    Terminal Schwann cells (TSCs) that cover motor neuron terminals, are known to play an important role in maintaining neuromuscular junctions, as well as in the repair process after nerve injury. However, the molecular characteristics of TSCs remain unknown, because of the difficulties in analyzing them due to their paucity. By using our previously reported method of selectively and efficiently collecting TSCs, we have analyzed the difference in expression patterns of lysophospholipid (LPL) receptor genes (LPA1, LPA2, LPA3, S1P1, S1P2, S1P3, S1P4, and S1P5) between TSCs and myelinating Schwann cells (MSCs). LPL, which includes lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P), is the bioactive lipid that induces a myriad of cellular responses through specific members of G-protein coupled receptors for LPA. It turned out that LPA3 was expressed only in TSCs, whereas S1P1 was expressed in TSCs and skeletal muscle, but not in MSCs. Other types of LPL receptor genes, including LPA1, S1P2, S1P3, S1P4, were expressed in both types of Schwann cells. None of the LPL receptor gene family showed MSCs-specific expression. PMID:17375210

  14. Lysophospholipid receptors are differentially expressed in rat terminal Schwann cells, as revealed by a single cell rt-PCR and in situ hybridization.

    PubMed

    Kobashi, Hiroaki; Yaoi, Takeshi; Oda, Ryo; Okajima, Seiichiro; Fujiwara, Hiroyoshi; Kubo, Toshikazu; Fushiki, Shinji

    2006-04-22

    Terminal Schwann cells (TSCs) that cover motor neuron terminals, are known to play an important role in maintaining neuromuscular junctions, as well as in the repair process after nerve injury. However, the molecular characteristics of TSCs remain unknown, because of the difficulties in analyzing them due to their paucity. By using our previously reported method of selectively and efficiently collecting TSCs, we have analyzed the difference in expression patterns of lysophospholipid (LPL) receptor genes (LPA1, LPA2, LPA3, S1P1, S1P2, S1P3, S1P4, and S1P5) between TSCs and myelinating Schwann cells (MSCs). LPL, which includes lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P), is the bioactive lipid that induces a myriad of cellular responses through specific members of G-protein coupled receptors for LPA. It turned out that LPA3 was expressed only in TSCs, whereas S1P1 was expressed in TSCs and skeletal muscle, but not in MSCs. Other types of LPL receptor genes, including LPA1, S1P2, S1P3, S1P4, were expressed in both types of Schwann cells. None of the LPL receptor gene family showed MSCs-specific expression. PMID:17375210

  15. Regulation of autotaxin expression and secretion by lysophosphatidate and sphingosine 1-phosphate[S

    PubMed Central

    Benesch, Matthew G. K.; Zhao, Yuan Y.; Curtis, Jonathan M.; McMullen, Todd P. W.; Brindley, David N.

    2015-01-01

    Autotaxin (ATX) is a secreted enzyme, which produces extracellular lysophosphatidate (LPA) from lysophosphatidylcholine (LPC). LPA activates six G protein-coupled receptors and this is essential for vasculogenesis during embryonic development. ATX is also involved in wound healing and inflammation, and in tumor growth, metastasis, and chemo-resistance. It is, therefore, important to understand how ATX is regulated. It was proposed that ATX activity is inhibited by its product LPA, or a related lipid called sphingosine 1-phosphate (S1P). We now show that this apparent inhibition is ineffective at the high concentrations of LPC that occur in vivo. Instead, feedback regulation by LPA and S1P is mediated by inhibition of ATX expression resulting from phosphatidylinositol-3-kinase activation. Inhibiting ATX activity in mice with ONO-8430506 severely decreased plasma LPA concentrations and increased ATX mRNA in adipose tissue, which is a major site of ATX production. Consequently, the amount of inhibitor-bound ATX protein in the plasma increased. We, therefore, demonstrate the concept that accumulation of LPA in the circulation decreases ATX production. However, this feedback regulation can be overcome by the inflammatory cytokines, TNF-α or interleukin 1β. This enables high LPA and ATX levels to coexist in inflammatory conditions. The results are discussed in terms of ATX regulation in wound healing and cancer. PMID:25896349

  16. Regulation of autotaxin expression and secretion by lysophosphatidate and sphingosine 1-phosphate.

    PubMed

    Benesch, Matthew G K; Zhao, Yuan Y; Curtis, Jonathan M; McMullen, Todd P W; Brindley, David N

    2015-06-01

    Autotaxin (ATX) is a secreted enzyme, which produces extracellular lysophosphatidate (LPA) from lysophosphatidylcholine (LPC). LPA activates six G protein-coupled receptors and this is essential for vasculogenesis during embryonic development. ATX is also involved in wound healing and inflammation, and in tumor growth, metastasis, and chemo-resistance. It is, therefore, important to understand how ATX is regulated. It was proposed that ATX activity is inhibited by its product LPA, or a related lipid called sphingosine 1-phosphate (S1P). We now show that this apparent inhibition is ineffective at the high concentrations of LPC that occur in vivo. Instead, feedback regulation by LPA and S1P is mediated by inhibition of ATX expression resulting from phosphatidylinositol-3-kinase activation. Inhibiting ATX activity in mice with ONO-8430506 severely decreased plasma LPA concentrations and increased ATX mRNA in adipose tissue, which is a major site of ATX production. Consequently, the amount of inhibitor-bound ATX protein in the plasma increased. We, therefore, demonstrate the concept that accumulation of LPA in the circulation decreases ATX production. However, this feedback regulation can be overcome by the inflammatory cytokines, TNF-α or interleukin 1β. This enables high LPA and ATX levels to coexist in inflammatory conditions. The results are discussed in terms of ATX regulation in wound healing and cancer. PMID:25896349

  17. Melatonin inhibits the sphingosine kinase 1/sphingosine-1-phosphate signaling pathway in rabbits with fulminant hepatitis of viral origin.

    PubMed

    Crespo, Irene; San-Miguel, Beatriz; Sánchez, Diana I; González-Fernández, Bárbara; Álvarez, Marcelino; González-Gallego, Javier; Tuñón, María J

    2016-09-01

    The sphingosine kinase (SphK)1/sphingosine-1-phosphate (S1P) pathway is involved in multiple biological processes, including liver diseases. This study investigate whether modulation of the SphK1/S1P system associates to the beneficial effects of melatonin in an animal model of acute liver failure (ALF) induced by the rabbit hemorrhagic disease virus (RHDV). Rabbits were experimentally infected with 2 × 10(4) hemagglutination units of a RHDV isolate and received 20 mg/kg of melatonin at 0, 12, and 24 hr postinfection. Liver mRNA levels, protein concentration, and immunohistochemical labeling for SphK1 increased in RHDV-infected rabbits. S1P production and protein expression of the S1PR1 receptor were significantly elevated following RHDV infection. These effects were significantly reduced by melatonin. Rabbits also exhibited increased expression of toll-like receptor (TLR)4, tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, nuclear factor-kappa B (NF-κB) p50 and p65 subunits, and phosphorylated inhibitor of kappa B (IκB)α. Melatonin administration significantly inhibited those changes and induced a decreased immunoreactivity for RHDV viral VP60 antigen in the liver. Results obtained indicate that the SphK1/S1P system activates in parallel to viral replication and the inflammatory process induced by the virus. Inhibition of the lipid signaling pathway by the indole reveals novel molecular pathways that may account for the protective effect of melatonin in this animal model of ALF, and supports the potential of melatonin as an antiviral agent. PMID:27101794

  18. Activation of RhoA, but Not Rac1, Mediates Early Stages of S1P-Induced Endothelial Barrier Enhancement.

    PubMed

    Zhang, Xun E; Adderley, Shaquria P; Breslin, Jerome W

    2016-01-01

    Compromised endothelial barrier function is a hallmark of inflammation. Rho family GTPases are critical in regulating endothelial barrier function, yet their precise roles, particularly in sphingosine-1-phosphate (S1P)-induced endothelial barrier enhancement, remain elusive. Confluent cultures of human umbilical vein endothelial cells (HUVEC) or human dermal microvascular endothelial cells (HDMEC) were used to model the endothelial barrier. Barrier function was assessed by determining the transendothelial electrical resistance (TER) using an electrical cell-substrate impedance sensor (ECIS). The roles of Rac1 and RhoA were tested in S1P-induced barrier enhancement. The results show that pharmacologic inhibition of Rac1 with Z62954982 failed to block S1P-induced barrier enhancement. Likewise, expression of a dominant negative form of Rac1, or knockdown of native Rac1 with siRNA, failed to block S1P-induced elevations in TER. In contrast, blockade of RhoA with the combination of the inhibitors Rhosin and Y16 significantly reduced S1P-induced increases in TER. Assessment of RhoA activation in real time using a fluorescence resonance energy transfer (FRET) biosensor showed that S1P increased RhoA activation primarily at the edges of cells, near junctions. This was complemented by myosin light chain-2 phosphorylation at cell edges, and increased F-actin and vinculin near intercellular junctions, which could all be blocked with pharmacologic inhibition of RhoA. The results suggest that S1P causes activation of RhoA at the cell periphery, stimulating local activation of the actin cytoskeleton and focal adhesions, and resulting in endothelial barrier enhancement. S1P-induced Rac1 activation, however, does not appear to have a significant role in this process. PMID:27187066

  19. Activation of RhoA, but Not Rac1, Mediates Early Stages of S1P-Induced Endothelial Barrier Enhancement

    PubMed Central

    Zhang, Xun E.; Adderley, Shaquria P.

    2016-01-01

    Compromised endothelial barrier function is a hallmark of inflammation. Rho family GTPases are critical in regulating endothelial barrier function, yet their precise roles, particularly in sphingosine-1-phosphate (S1P)-induced endothelial barrier enhancement, remain elusive. Confluent cultures of human umbilical vein endothelial cells (HUVEC) or human dermal microvascular endothelial cells (HDMEC) were used to model the endothelial barrier. Barrier function was assessed by determining the transendothelial electrical resistance (TER) using an electrical cell-substrate impedance sensor (ECIS). The roles of Rac1 and RhoA were tested in S1P-induced barrier enhancement. The results show that pharmacologic inhibition of Rac1 with Z62954982 failed to block S1P-induced barrier enhancement. Likewise, expression of a dominant negative form of Rac1, or knockdown of native Rac1 with siRNA, failed to block S1P-induced elevations in TER. In contrast, blockade of RhoA with the combination of the inhibitors Rhosin and Y16 significantly reduced S1P-induced increases in TER. Assessment of RhoA activation in real time using a fluorescence resonance energy transfer (FRET) biosensor showed that S1P increased RhoA activation primarily at the edges of cells, near junctions. This was complemented by myosin light chain-2 phosphorylation at cell edges, and increased F-actin and vinculin near intercellular junctions, which could all be blocked with pharmacologic inhibition of RhoA. The results suggest that S1P causes activation of RhoA at the cell periphery, stimulating local activation of the actin cytoskeleton and focal adhesions, and resulting in endothelial barrier enhancement. S1P-induced Rac1 activation, however, does not appear to have a significant role in this process. PMID:27187066

  20. Sphingosine 1-phosphate induced anti-atherogenic and atheroprotective M2 macrophage polarization through IL-4.

    PubMed

    Park, Soo-Jin; Lee, Kyoung-Pil; Kang, Saeromi; Lee, Jaewon; Sato, Koichi; Chung, Hae Young; Okajima, Fumikazu; Im, Dong-Soon

    2014-10-01

    Sphingosine 1-phosphate (S1P) has been implicated in anti-atherogenic properties of high-density lipoproteins. However, the roles and signaling of S1P in macrophages, the main contributor to atherosclerosis, have not been well studied. Furthermore, pro-inflammatory M1 and anti-inflammatory M2 macrophage phenotypes may influence the development of atherosclerosis. Therefore, we investigated the effects of S1P on macrophage phenotypes, especially on M2 polarization and its signaling in relation to the anti-atherogenic properties of S1P. It was found that S1P induced anti-inflammatory M2 polarization via IL-4 secretion and its signaling, and induced IL-4Rα and IL-2Rγ. In addition, down-stream signalings, such as, stat-6 phosphorylation, SOCS1 induction, and SOCS3 suppression were also observed in macrophages in response to S1P. Furthermore, S1P-induced ERK activation, and the inhibitions of p38 MAPK and JNK were found to be key signals for IL-4 induction. Moreover, the anti-atherogenic effect of S1P in HDL was confirmed by the observation that oxidized LDL-induced lipid accumulation was attenuated in S1P-treated M2 macrophages. Furthermore, the atheroprotective effect of S1P was demonstrated by its anti-apoptotic effect on S1P-treated macrophages. The present study shows that S1P-induced M2 polarization of macrophages could be mediated via IL-4 signaling, and suggests that M2 polarization by S1P is responsible for the anti-atherogenic and atheroprotective properties of high-density lipoproteins in vivo.

  1. Potential signaling pathway involved in sphingosine-1-phosphate-induced epithelial-mesenchymal transition in cancer

    PubMed Central

    ZENG, YE; YAO, XING-HONG; YAN, ZHI-PING; LIU, JING-XIA; LIU, XIAO-HENG

    2016-01-01

    The developmental process of epithelial-mesenchymal transition (EMT) occurs when epithelial cells acquire invasive mesenchymal cell characteristics, and the activation of this process has been indicated to be involved in tumor progression. EMT could be induced by growth factors, cytokines and matrix metalloproteinases (MMPs). sphingosine-1-phosphate (S1P) is a biologically-active lipid that plays an important role in cancer metastasis. S1P also contributes to the activation of EMT. However, the mechanism underlying S1P-induced EMT is unclear. Increased evidence has demonstrated that the cell surface glycocalyx is closed associated with S1P and plays an important role in tumor progression, suggesting that S1P-induced EMT could be Snail-MMP signaling-dependent. Thus, we hypothesize that an S1P-glycocalyx-Snail-MMP signaling axis mediates S1P-induced EMT. This is an essential step towards improved understanding of the underlying mechanism involved in S1P-regulted EMT, and the development of novel diagnostic and anticancer therapeutic strategies. PMID:27347154

  2. Sphingosine-1-phosphate Maintains Normal Vascular Permeability by Preserving Endothelial Surface Glycocalyx in Intact Microvessels

    PubMed Central

    Zhang, Lin; Zeng, Min; Fan, Jie; Tarbell, John, M.; Curry, Fitz-Roy E.; Fu, Bingmei M.

    2016-01-01

    Objective Sphingosine-1-phosphate (S1P) was found to protect the endothelial surface glycocalyx (ESG) by inhibiting matrix metalloproteinase (MMP) activity-dependent shedding of ESG in cultured endothelial cell studies. We aimed to further test that S1P contributes to the maintenance of normal vascular permeability by protecting the ESG in intact microvessels. Methods We quantified the ESG in post-capillary venules of rat mesentery and measured the vascular permeability to albumin in the presence and absence of 1 μM S1P. We also measured permeability to albumin in the presence of MMP inhibitors and compared the measured permeability with those predicted by a transport model for the inter-endothelial cleft. Results We found that in the absence of S1P, the fluorescence intensity of the FITC-anti-heparan sulfate labeled ESG was ~10% of that in the presence of S1P, while the measured permeability to albumin was ~6.5 fold that in the presence of S1P. Similar results were observed with MMP inhibition. The predictions by the mathematical model further confirmed that S1P maintains microvascular permeability by preserving ESG. Conclusions Our results show that S1P contributes to the maintenance of normal vascular permeability by protecting the ESG in intact microvessels, consistent with parallel observation in cultured endothelial monolayers. PMID:27015105

  3. Sphingosine-1 Phosphate: A New Modulator of Immune Plasticity in the Tumor Microenvironment

    PubMed Central

    Rodriguez, Yamila I.; Campos, Ludmila E.; Castro, Melina G.; Aladhami, Ahmed; Oskeritzian, Carole A.; Alvarez, Sergio E.

    2016-01-01

    In the last 15 years, increasing evidences demonstrate a strong link between sphingosine-1-phosphate (S1P) and both normal physiology and progression of different diseases, including cancer and inflammation. Indeed, numerous studies show that tissue levels of this sphingolipid metabolite are augmented in many cancers, affecting survival, proliferation, angiogenesis, and metastatic spread. Recent insights into the possible role of S1P as a therapeutic target has attracted enormous attention and opened new opportunities in this evolving field. In this review, we will focus on the role of S1P in cancer, with particular emphasis in new developments that highlight the many functions of this sphingolipid in the tumor microenvironment. We will discuss how S1P modulates phenotypic plasticity of macrophages and mast cells, tumor-induced immune evasion, differentiation and survival of immune cells in the tumor milieu, interaction between cancer and stromal cells, and hypoxic response. PMID:27800303

  4. Delivery of sphingosine 1-phosphate from poly(ethylene glycol) hydrogels

    PubMed Central

    Wacker, Bradley K.; Scott, Evan A.; Kaneda, Megan M.; Alford, Shannon K.; Elbert, Donald L.

    2008-01-01

    While protein growth factors promote therapeutic angiogenesis, delivery of lipid factors such as sphingosine 1-phosphate (S1P) may provide better stabilization of newly formed vessels. We developed a biomaterial for the controlled delivery of S1P, a bioactive lipid released from activated platelets. Multi-arm poly(ethylene glycol)-vinyl sulfone was crosslinked with albumin, a lipid-transporting protein, to form hydrogels. The rate of S1P release from the materials followed Fickian kinetics and was dependent upon the presence of lipid carriers in the release solution. Delivery of S1P from RGD-modified hydrogels increased the cell migration speed of endothelial cells growing on the materials. The materials also induced angiogenesis in the chorioallantoic membrane assay. Our data demonstrate that the storage and release of lipid factors provides a new route for the induction of angiogenesis by artificial materials. PMID:16602758

  5. Binding of the sphingolipid S1P to hTERT stabilizes telomerase at the nuclear periphery by allosterically mimicking protein phosphorylation†

    PubMed Central

    Selvam, Shanmugam P.; De Palma, Ryan M.; Oaks, Joshua J.; Oleinik, Natalia; Peterson, Yuri K.; Stahelin, Robert V.; Skordalakes, Emmanuel; Ponnusamy, Suriyan; Garrett-Mayer, Elizabeth; Smith, Charles D.; Ogretmen, Besim

    2015-01-01

    During DNA replication, the enzyme telomerase maintains the ends of chromosomes, called telomeres. Shortened telomeres trigger cell senescence, and cancer cells often have increased telomerase activity to promote their ability to proliferate indefinitely. The catalytic subunit, human telomerase reverse transcriptase (hTERT), is stabilized by phosphorylation. Here, we found that the lysophospholipid sphingosine 1-phosphate (S1P), generated by sphingosine kinase 2 (SK2), bound hTERT at the nuclear periphery in human and mouse fibroblasts. Docking predictions and mutational analyses revealed that binding occurred between a hydroxyl group (C′3-OH) in S1P and Asp684 in hTERT. Inhibiting or depleting SK2 or mutating the S1P binding site decreased the stability of hTERT in cultured cells and promoted senescence and loss of telomere integrity. S1P binding inhibited the interaction of hTERT with MKRN1, an E3 ubiquitin ligase that tags hTERT for degradation. Murine Lewis lung carcinoma (LLC) cells formed smaller tumors in mice lacking SK2 than in wild-type mice, and knocking down SK2 in LLC cells before implantation into mice suppressed their growth. Pharmacologically inhibiting SK2 decreased the growth of subcutaneous A549 lung cancer cell-derived xenografts in mice, and expression of wild-type hTERT, but not an S1P-binding mutant, restored tumor growth. Thus, our data suggest that S1P binding to hTERT allosterically mimicks phosphorylation, promoting telomerase stability and hence telomere maintenance, cell proliferation, and tumor growth PMID:26082434

  6. Amphiphilic degradable polymers for immobilization and sustained delivery of sphingosine 1-phosphate

    PubMed Central

    Zhang, Jing; Song, Jie

    2014-01-01

    Controlled delivery of angiogenic factor sphingosine 1-phosphate (S1P) represents a promising strategy for promoting vascularization during tissue repair and regeneration. In this study, we developed an amphiphilic biodegradable polymer platform for the stable encapsulation and sustained release of S1P. Mimicking the interaction between amphiphilic S1P and its binding proteins, a series of polymers with hydrophilic poly(ethylene glycol) core and lipophilic flanking segments of polylactide and/or poly(alkylated lactide) with different alkyl chain lengths were synthesized. These polymers were electrospun into fibrous meshes, and loaded with S1P in generally high loading efficiencies (>90%). Sustained S1P release from these scaffolds could be tuned by adjusting the alkyl chain length, blockiness and lipophilic block length, achieving 35-55% and 45-80% accumulative releases in the first 8 h and by 7 days, respectively. Furthermore, using endothelial cell tube formation assay and chicken chorioallantoic membrane (CAM) assay, we showed that the different S1P loading doses and release kinetics translated into distinct pro-angiogenic outcomes. These results suggest that these amphiphilic polymers are effective delivery vehicles for S1P and may be explored as tissue engineering scaffolds where the delivery of lipophilic or amphiphilic bioactive factors are desired. PMID:24631657

  7. Amphiphilic degradable polymers for immobilization and sustained delivery of sphingosine 1-phosphate.

    PubMed

    Zhang, Jing; Song, Jie

    2014-07-01

    Controlled delivery of the angiogenic factor sphingosine 1-phosphate (S1P) represents a promising strategy for promoting vascularization during tissue repair and regeneration. In this study, we developed an amphiphilic biodegradable polymer platform for the stable encapsulation and sustained release of S1P. Mimicking the interaction between amphiphilic S1P and its binding proteins, a series of polymers with hydrophilic poly(ethylene glycol) core and lipophilic flanking segments of polylactide and/or poly(alkylated lactide) with different alkyl chain lengths were synthesized. These polymers were electrospun into fibrous meshes, and loaded with S1P in generally high loading efficiencies (>90%). Sustained S1P release from these scaffolds could be tuned by adjusting the alkyl chain length, blockiness and lipophilic block length, achieving 35-55% and 45-80% accumulative releases in the first 8h and by 7 days, respectively. Furthermore, using endothelial cell tube formation assay and chicken chorioallantoic membrane assay, we showed that the different S1P loading doses and release kinetics translated into distinct pro-angiogenic outcomes. These results suggest that these amphiphilic polymers are effective delivery vehicles for S1P and may be explored as tissue engineering scaffolds where the delivery of lipophilic or amphiphilic bioactive factors is desired.

  8. Involvement of lysophosphatidic acid, sphingosine 1-phosphate and ceramide 1-phosphate in the metabolization of phosphatidic acid by lipid phosphate phosphatases in bovine rod outer segments.

    PubMed

    Pasquaré, Susana J; Salvador, Gabriela A; Giusto, Norma Maria

    2008-07-01

    The aim of the present research was to evaluate the generation of [2-3H]diacylglycerol ([2-3H]DAG) from [2-3H]-Phosphatidic acid ([2-3H]PA) by lipid phosphate phosphatases (LPPs) at different concentrations of lysophosphatidic acid (LPA), sphingosine 1-phosphate (S1P), and ceramide 1-phosphate (C1P) in purified ROS obtained from dark-adapted retinas (DROS) or light-adapted retinas (BLROS) as well as in ROS membrane preparations depleted of soluble and peripheral proteins. Western blot analysis revealed the presence of LPP3 exclusively in all membrane preparations. Immunoblots of entire ROS and depleted ROS did not show dark-light differences in LPP3 levels. LPPs activities were diminished by 53% in BLROS with respect to DROS. The major competitive effect on PA hydrolysis was exerted by LPA and S1P in DROS and by C1P in BLROS. LPPs activities in depleted ROS were similar to the activity observed in entire DROS and BLROS, respectively. LPA, S1P and C1P competed at different extent in depleted DROS and BLROS. Sphingosine and ceramide inhibited LPPs activities in entire and depleted DROS. Ceramide also inhibited LPPs activities in entire and in depleted BLROS. Our findings are indicative of a different degree of competition between PA and LPA, S1P and C1P by LPPs depending on the illumination state of the retina. PMID:18288612

  9. Evidence for the involvement of sphingosine-1-phosphate in the homing and engraftment of hematopoietic stem cells to bone marrow

    PubMed Central

    Adamiak, Mateusz; Borkowska, Sylwia; Wysoczynski, Marcin; Suszynska, Malwina; Kucia, Magda; Rokosh, Gregg; Abdel-Latif, Ahmed; Ratajczak, Janina; Ratajczak, Mariusz Z.

    2015-01-01

    The α-chemokine stromal-derived factor 1 (SDF-1), which binds to the CXCR4 receptor, directs migration and homing of CXCR4+ hematopoietic stem/progenitor cells (HSPCs) to bone marrow (BM) stem cell niches. Nevertheless, it is also known that CXCR4−/− fetal liver-derived hematopoietic stem cells engraft into BM and that blockade of CXCR4 by its antagonist AMD3100 does not prevent engraftment of HSPCs. Because of this finding of SDF-1-CXCR4-independent BM homing, the unique role of SDF-1 in HSPC homing has recently been challenged. While SDF-1 is the only chemokine that chemoattracts HSPCs, other chemoattractants for these cells have recently been described, including the bioactive phosphosphingolipid sphingosine-1-phosphate (S1P). To address the potential role of S1P in homing of HSPCs to BM, we performed hematopoietic transplants into mice deficient in BM-expressed sphingosine kinase 1 (Sphk1−/−) using hematopoietic cells from normal control mice as well as cells from mice in which floxed CXCR4 (CXCR4fl/fl) was conditionally deleted. We observed the presence of a homing and engraftment defect in HSPCs of Sphk1−/− mice that was particularly profound after transplantation of CXCR4−/− BM cells. Thus, our results indicate that BM-microenvironment-expressed S1P plays a role in homing of HSPCs. They also support the concept that, in addition to the SDF-1-CXCR4 axis, other chemotactic axes are also involved in homing and engraftment of HSPCs. PMID:26299919

  10. Lysophosphatidic Acid and Sphingosine-1-Phosphate: A Concise Review of Biological Function and Applications for Tissue Engineering.

    PubMed

    Binder, Bernard Y K; Williams, Priscilla A; Silva, Eduardo A; Leach, J Kent

    2015-12-01

    The presentation and controlled release of bioactive signals to direct cellular growth and differentiation represents a widely used strategy in tissue engineering. Historically, work in this field has primarily focused on the delivery of large cytokines and growth factors, which can be costly to manufacture and difficult to deliver in a sustained manner. There has been a marked increase over the past decade in the pursuit of lipid mediators due to their wide range of effects over multiple cell types, low cost, and ease of scale-up. Lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) are two bioactive lysophospholipids (LPLs) that have gained attention for use as pharmacological agents in tissue engineering applications. While these lipids can have similar effects on cellular response, they possess distinct chemical backbones, mechanisms of synthesis and degradation, and signaling pathways using a discrete set of G-protein-coupled receptors (GPCRs). LPA and S1P predominantly act extracellularly on their GPCRs and can directly regulate cell survival, differentiation, cytokine secretion, proliferation, and migration--each of the important functions that must be considered in regenerative medicine. In addition to these potent physiological functions, these LPLs play pivotal roles in a number of pathophysiological processes. To capitalize on the promise of these molecules in tissue engineering, these lipids have been incorporated into biomaterials for in vivo delivery. Here, we survey the effects of LPA and S1P on both cellular- and tissue-level phenotypes, with an eye toward regulating stem/progenitor cell growth and differentiation. In particular, we examine work that has translational applications for cell-based tissue engineering strategies in promoting cell survival, bone and cartilage engineering, and therapeutic angiogenesis.

  11. Lysophosphatidic Acid and Sphingosine-1-Phosphate: A Concise Review of Biological Function and Applications for Tissue Engineering.

    PubMed

    Binder, Bernard Y K; Williams, Priscilla A; Silva, Eduardo A; Leach, J Kent

    2015-12-01

    The presentation and controlled release of bioactive signals to direct cellular growth and differentiation represents a widely used strategy in tissue engineering. Historically, work in this field has primarily focused on the delivery of large cytokines and growth factors, which can be costly to manufacture and difficult to deliver in a sustained manner. There has been a marked increase over the past decade in the pursuit of lipid mediators due to their wide range of effects over multiple cell types, low cost, and ease of scale-up. Lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) are two bioactive lysophospholipids (LPLs) that have gained attention for use as pharmacological agents in tissue engineering applications. While these lipids can have similar effects on cellular response, they possess distinct chemical backbones, mechanisms of synthesis and degradation, and signaling pathways using a discrete set of G-protein-coupled receptors (GPCRs). LPA and S1P predominantly act extracellularly on their GPCRs and can directly regulate cell survival, differentiation, cytokine secretion, proliferation, and migration--each of the important functions that must be considered in regenerative medicine. In addition to these potent physiological functions, these LPLs play pivotal roles in a number of pathophysiological processes. To capitalize on the promise of these molecules in tissue engineering, these lipids have been incorporated into biomaterials for in vivo delivery. Here, we survey the effects of LPA and S1P on both cellular- and tissue-level phenotypes, with an eye toward regulating stem/progenitor cell growth and differentiation. In particular, we examine work that has translational applications for cell-based tissue engineering strategies in promoting cell survival, bone and cartilage engineering, and therapeutic angiogenesis. PMID:26035484

  12. Sphingosine kinase 1 activation enhances epidermal innate immunity through sphingosine-1-phosphate stimulation of cathelicidin production

    PubMed Central

    Jeong, Se Kyoo; Kim, Young Il; Shin, Kyong-Oh; Kim, Bong-Woo; Lee, Sin Hee; Jeon, Jeong Eun; Kim, Hyun Jong; Lee, Yong-Moon; Mauro, Theodora M.; Elias, Peter M.; Uchida, Yoshikazu; Park, Kyungho

    2015-01-01

    Background The ceramide metabolite, sphingosine-1-phosphate (S1P), regulates multiple cellular functions in keratinocytes (KC). We recently discovered that production of a key innate immune element, cathelicidin antimicrobial peptide (CAMP), is stimulated via a NF-κB-dependent mechanism that is activated by S1P when S1P is generated by sphingosine kinase (SPHK) 1. Objective We investigated whether pharmacological modulation of SPHK1 activity, using a novel synthetic SPHK1 activator, (S)-Methyl 2-(hexanamide)-3-(4-hydroxyphenyl) propanoate (MHP), stimulates CAMP expression. Methods MHP-mediated changes in both S1P and CAMP downstream mediators were analyzed in normal cultured human KC by qRT-PCR, Western immunoblot, ELISA, confocal microscopy for immunohistochemistry, HPLC and ESI-LC/MS/MS, and microbial pathogen invasion/colonization in a human epidermal organotypic model. Results Treatment with MHP directly activated SPHK1 and increased cellular S1P content in normal cultured human KC. Because MHP did not inhibit S1P lyase activity, which hydrolyses S1P, augumented S1P levels could be attributed to increased synthesis rather than blockade of S1P degradation. Next, we found that exogenous MHP significantly stimulated CAMP mRNA and protein production in KC, increases that were significantly suppressed by siRNA directed against SPHK1, but not by a scrambled control siRNA. NF-κB activation, assessed by nuclear translocation of NF-κB, occurred in cells following incubation with MHP. Conversely, pretreatment with a specific inhibitor of SPHK1 decreased MHP-induced nuclear translocation of NF-κB, and significantly attenuated the MHP-mediated increase in CAMP production. Finally, topical MHP significantly suppressed invasion of the virulent Staphylococcus aureus into murine skin explants. Conclusion MHP activation of SPHK1, a target enzyme of CAMP production, can stimulate innate immunity. PMID:26113114

  13. Sphingosine-1-phosphate, regulated by FSH and VEGF, stimulates granulosa cell proliferation.

    PubMed

    Hernández-Coronado, C G; Guzmán, A; Rodríguez, A; Mondragón, J A; Romano, M C; Gutiérrez, C G; Rosales-Torres, A M

    2016-09-15

    Sphingosine-1-phosphate (S1P) is a bioactive polar sphingolipid which stimulates proliferation, growth and survival in various cell types. In the ovary S1P has been shown protect the granulosa cells and oocytes from insults such as oxidative stress and radiotherapy, and S1P concentrations are greater in healthy than atretic large follicles. Hence, we postulate that S1P is fundamental in follicle development and that it is activated in ovarian granulosa cells in response to FSH and VEGF. To test this hypothesis we set out: i) to evaluate the effect of FSH and VEGF on S1P synthesis in cultured bovine granulosa cells and ii) to analyse the effect of S1P on proliferation and survival of bovine granulosa cells in vitro. Seventy five thousand bovine granulosa cells from healthy medium-sized (4-7mm) follicles were cultured in 96-well plates in McCoy's 5a medium containing 10ng/mL of insulin and 1ng/mL of LR-IGF-I at 37°C in a 5% CO2/air atmosphere at 37°C. Granulosa cell production of S1P was tested in response to treatment with FSH (0, 0.1, 1 and 10ng/mL) and VEGF (0, 0.01, 0.1, 1, 10 and 100ng/mL) and measured by HPLC. Granulosa cells produced S1P at 48 and 96h, with the maximum production observed with 1ng/mL of FSH. Likewise, 0.01ng/mL of VEGF stimulated S1P production at 48, but not 96h of culture. Further, the granulosa cell expression of sphingosine kinase-1 (SK1), responsible for S1P synthesis, was demonstrated by Western blot after 48h of culture. FSH increased the expression of phosphorylated SK1 (P<0.05) and the addition of a SK1 inhibitor reduced the constitutive and FSH-stimulated S1P synthesis (P<0.05). Sphingosine-1-phosphate had a biphasic effect on granulosa cell number after culture. At low concentration S1P (0.1μM) increased granulosa cell number after 48h of culture (P<0.05) and the proportion of cells in the G2 and M phase of the cell cycle (P<0.05), whereas higher concentrations decreased cell number (10μM; P<0.05) by an increase (P<0.05) in the

  14. Transforming growth factor-β-sphingosine kinase 1/S1P signaling upregulates microRNA-21 to promote fibrosis in renal tubular epithelial cells

    PubMed Central

    Hong, Quan; Wang, Zhen; Yu, Yanyan; Zou, Xin; Xu, Lihong

    2015-01-01

    Renal fibrosis is a progressive pathological change characterized by tubular cell apoptosis, tubulointerstitial fibroblast proliferation, and excessive deposition of extracellular matrix (ECM). miR-21 has been implicated in transforming growth factor-β (TGF-β)-stimulated tissue fibrosis. Recent studies showed that sphingosine kinase/sphingosine-1-phosphate (SphK/S1P) are also critical for TGF-β-stimulated tissue fibrosis; however, it is not clear whether SphK/S1P interacts with miR-21 or not. In this study, we hypothesized that SphK/S1P signaling is linked to upregulation of miR-21 by TGF-β. To verify this hypothesis, we first determined that miR-21 was highly expressed in renal tubular epithelial cells (TECs) stimulated with TGF-β by using qRT-PCR and Northern blotting. Simultaneously, inhibition of miR-21, mediated by the corresponding antimir, markedly decreased the expression and deposition of type I collagen, fibronectin (Fn), cysteine-rich protein 61 (CCN1), α-smooth muscle actin, and fibroblast-specific protein1 in TGF-β-treated TECs. ELISA and qRT-PCR were used to measure the S1P and SphK1 levels in TECs. S1P production was induced by TGF-β through activation of SphK1. Furthermore, it was observed that TGF-β-stimulated upregulation of miR-21 was abolished by SphK1 siRNA and was restored by the addition of exogenous S1P. Blocking S1PR2 also inhibited upregulation of miR-21. Additionally, miR-21 overexpression attenuated the repression of TGF-β-stimulated ECM deposition and epithelial–mesenchymal transition by SphK1 and S1PR2 siRNA. In summary, our study demonstrates a link between SphK1/S1P and TGF-β-induced miR-21 in renal TECs and may represent a novel therapeutic target in renal fibrosis. PMID:26376826

  15. Sphingosine-1-phosphate is involved in the occlusive arteriopathy of pulmonary arterial hypertension

    PubMed Central

    Joshi, Sachindra R.; Bastola, Mrigendra M.; McLendon, Jared M.; Oka, Masahiko; Fagan, Karen A.; McMurtry, Ivan F.

    2016-01-01

    Abstract Despite several advances in the pathobiology of pulmonary arterial hypertension (PAH), its pathogenesis is not completely understood. Current therapy improves symptoms but has disappointing effects on survival. Sphingosine-1-phosphate (S1P) is a lysophospholipid synthesized by sphingosine kinase 1 (SphK1) and SphK2. Considering the regulatory roles of S1P in several tissues leading to vasoconstriction, inflammation, proliferation, and fibrosis, we investigated whether S1P plays a role in the pathogenesis of PAH. To test this hypothesis, we used plasma samples and lung tissue from patients with idiopathic PAH (IPAH) and the Sugen5416/hypoxia/normoxia rat model of occlusive PAH. Our study revealed an increase in the plasma concentration of S1P in patients with IPAH and in early and late stages of PAH in rats. We observed increased expression of both SphK1 and SphK2 in the remodeled pulmonary arteries of patients with IPAH and PAH rats. Exogenous S1P stimulated the proliferation of cultured rat pulmonary arterial endothelial and smooth-muscle cells. We also found that 3 weeks of treatment of late-stage PAH rats with an SphK1 inhibitor reduced the increased plasma levels of S1P and the occlusive pulmonary arteriopathy. Although inhibition of SphK1 improved cardiac index and the total pulmonary artery resistance index, it did not reduce right ventricular systolic pressure or right ventricular hypertrophy. Our study supports that S1P is involved in the pathogenesis of occlusive arteriopathy in PAH and provides further evidence that S1P signaling may be a novel therapeutic target. PMID:27683614

  16. Sphingosine-1-phosphate is involved in the occlusive arteriopathy of pulmonary arterial hypertension.

    PubMed

    Gairhe, Salina; Joshi, Sachindra R; Bastola, Mrigendra M; McLendon, Jared M; Oka, Masahiko; Fagan, Karen A; McMurtry, Ivan F

    2016-09-01

    Despite several advances in the pathobiology of pulmonary arterial hypertension (PAH), its pathogenesis is not completely understood. Current therapy improves symptoms but has disappointing effects on survival. Sphingosine-1-phosphate (S1P) is a lysophospholipid synthesized by sphingosine kinase 1 (SphK1) and SphK2. Considering the regulatory roles of S1P in several tissues leading to vasoconstriction, inflammation, proliferation, and fibrosis, we investigated whether S1P plays a role in the pathogenesis of PAH. To test this hypothesis, we used plasma samples and lung tissue from patients with idiopathic PAH (IPAH) and the Sugen5416/hypoxia/normoxia rat model of occlusive PAH. Our study revealed an increase in the plasma concentration of S1P in patients with IPAH and in early and late stages of PAH in rats. We observed increased expression of both SphK1 and SphK2 in the remodeled pulmonary arteries of patients with IPAH and PAH rats. Exogenous S1P stimulated the proliferation of cultured rat pulmonary arterial endothelial and smooth-muscle cells. We also found that 3 weeks of treatment of late-stage PAH rats with an SphK1 inhibitor reduced the increased plasma levels of S1P and the occlusive pulmonary arteriopathy. Although inhibition of SphK1 improved cardiac index and the total pulmonary artery resistance index, it did not reduce right ventricular systolic pressure or right ventricular hypertrophy. Our study supports that S1P is involved in the pathogenesis of occlusive arteriopathy in PAH and provides further evidence that S1P signaling may be a novel therapeutic target. PMID:27683614

  17. Sphingosine-1-phosphate is involved in the occlusive arteriopathy of pulmonary arterial hypertension

    PubMed Central

    Joshi, Sachindra R.; Bastola, Mrigendra M.; McLendon, Jared M.; Oka, Masahiko; Fagan, Karen A.; McMurtry, Ivan F.

    2016-01-01

    Abstract Despite several advances in the pathobiology of pulmonary arterial hypertension (PAH), its pathogenesis is not completely understood. Current therapy improves symptoms but has disappointing effects on survival. Sphingosine-1-phosphate (S1P) is a lysophospholipid synthesized by sphingosine kinase 1 (SphK1) and SphK2. Considering the regulatory roles of S1P in several tissues leading to vasoconstriction, inflammation, proliferation, and fibrosis, we investigated whether S1P plays a role in the pathogenesis of PAH. To test this hypothesis, we used plasma samples and lung tissue from patients with idiopathic PAH (IPAH) and the Sugen5416/hypoxia/normoxia rat model of occlusive PAH. Our study revealed an increase in the plasma concentration of S1P in patients with IPAH and in early and late stages of PAH in rats. We observed increased expression of both SphK1 and SphK2 in the remodeled pulmonary arteries of patients with IPAH and PAH rats. Exogenous S1P stimulated the proliferation of cultured rat pulmonary arterial endothelial and smooth-muscle cells. We also found that 3 weeks of treatment of late-stage PAH rats with an SphK1 inhibitor reduced the increased plasma levels of S1P and the occlusive pulmonary arteriopathy. Although inhibition of SphK1 improved cardiac index and the total pulmonary artery resistance index, it did not reduce right ventricular systolic pressure or right ventricular hypertrophy. Our study supports that S1P is involved in the pathogenesis of occlusive arteriopathy in PAH and provides further evidence that S1P signaling may be a novel therapeutic target.

  18. Nephrokeli, a Chinese Herbal Formula, May Improve IgA Nephropathy through Regulation of the Sphingosine-1-Phosphate Pathway

    PubMed Central

    Zhong, Yifei; Wang, Ke; Zhang, Xianwen; Cai, Xiaofan; Chen, Yiping; Deng, Yueyi

    2015-01-01

    Nephrokeli (NPKL) is a Chinese herbal formula that has been used to treat patients with IgA nephropathy (IgAN) for improvement of proteinuria and kidney injury. However, the mechanism remains unclear. Sphingosine-1-phosphate (S1P) and its receptors S1PR2 and S1PR3 are known to play an important role in kidney disease. Here, we tested whether NPKL is able to regulate the S1P pathway in the kidney of IgAN rats. Four groups of rats were included in the study: Control, IgAN, IgAN treated with losartan, and IgAN treated with NPKL. The IgAN model was generated by injection of bovine serum albumin and staphylococcus enterotoxin B. We found that IgAN rats had increased staining for proliferating cell nuclear antigen (PCNA) in the mesangial area and increased mRNA and protein levels of S1PR2 and S1PR3 in the kidney compared to control rats. Connective tissue growth factor (CTGF), a downstream growth factor in the S1P pathway, was also elevated in the kidney of IgAN rats. Treatment with either NPKL or losartan was able to reduce PCNA staining and the expression of both S1PR2 and S1PR3 in the kidney of IgAN rats. However, NPKL (but not losartan treatment) reduced the expression of CTGF in the kidney of IgAN rats. In addition, we treated rat mesangial cells with sera collected from either NPKL-treated rats or control rats and found that NPKL-serum was able to reduce S1P-induced mesangial cell proliferation and the expression of S1PR2/S1PR3 and CTGF. NPKL also attenuates expression of fibrosis, inflammation, and oxidative stress markers in the kidney of IgAN rats. Our studies provide the mechanism by which NPKL attenuates kidney injury in IgAN rats. PMID:25633986

  19. Sphingosine-1-phosphate promotes erythrocyte glycolysis and oxygen release for adaptation to high-altitude hypoxia

    PubMed Central

    Sun, Kaiqi; Zhang, Yujin; D'Alessandro, Angelo; Nemkov, Travis; Song, Anren; Wu, Hongyu; Liu, Hong; Adebiyi, Morayo; Huang, Aji; Wen, Yuan E.; Bogdanov, Mikhail V.; Vila, Alejandro; O'Brien, John; Kellems, Rodney E.; Dowhan, William; Subudhi, Andrew W.; Jameson-Van Houten, Sonja; Julian, Colleen G.; Lovering, Andrew T.; Safo, Martin; Hansen, Kirk C.; Roach, Robert C.; Xia, Yang

    2016-01-01

    Sphingosine-1-phosphate (S1P) is a bioactive signalling lipid highly enriched in mature erythrocytes, with unknown functions pertaining to erythrocyte physiology. Here by employing nonbiased high-throughput metabolomic profiling, we show that erythrocyte S1P levels rapidly increase in 21 healthy lowland volunteers at 5,260 m altitude on day 1 and continue increasing to 16 days with concurrently elevated erythrocyte sphingonisne kinase 1 (Sphk1) activity and haemoglobin (Hb) oxygen (O2) release capacity. Mouse genetic studies show that elevated erythrocyte Sphk1-induced S1P protects against tissue hypoxia by inducing O2 release. Mechanistically, we show that intracellular S1P promotes deoxygenated Hb anchoring to the membrane, enhances the release of membrane-bound glycolytic enzymes to the cytosol, induces glycolysis and thus the production of 2,3-bisphosphoglycerate (2,3-BPG), an erythrocyte-specific glycolytic intermediate, which facilitates O2 release. Altogether, we reveal S1P as an intracellular hypoxia-responsive biolipid promoting erythrocyte glycolysis, O2 delivery and thus new therapeutic opportunities to counteract tissue hypoxia. PMID:27417539

  20. SKI-1/S1P inhibitor PF-429242 impairs the onset of HCV infection.

    PubMed

    Blanchet, Matthieu; Sureau, Camille; Guévin, Carl; Seidah, Nabil G; Labonté, Patrick

    2015-03-01

    Worldwide, approximately 170 million individuals are afflicted with chronic hepatitis C virus (HCV) infection. To prevent the development of inherent diseases such as cirrhosis and hepatocellular carcinoma, tremendous efforts have been made, leading to the development of promising new treatments. However, their efficiency is still dependent on the viral genotype. Additionally, these treatments that target the virus directly can trigger the emergence of resistant variants. In a previous study, we have demonstrated that a long-term (72h) inhibition of SKI-1/S1P, a master lipogenic pathway regulator through activation of SREBP, resulted in impaired HCV genome replication and infectious virion secretion. In the present study, we sought to investigate the antiviral effect of the SKI-1/S1P small molecule inhibitor PF-429242 at the early steps of the HCV lifecycle. Our results indicate a very potent antiviral effect of the inhibitor early in the viral lifecycle and that the overall action of the compound relies on two different contributions. The first one is SREBP/SKI-1/S1P dependent and involves LDLR and NPC1L1 proteins, while the second one is SREBP independent. Overall, our study confirms that SKI-1/S1P is a relevant target to impair HCV infection and that PF-429242 could be a promising candidate in the field of HCV infection treatment.

  1. Bioactive lipids sphingosine-1-phosphate and ceramide-1-phosphate are pro-metastatic factors in human rhabdomyosarcomas cell lines, and their tissue level increases in response to radio/chemotherapy

    PubMed Central

    Schneider, Gabriela; Bryndza, Ewa; Abdel-Latif, Ahmed; Ratajczak, Janina; Maj, Magdalena; Tarnowski, Maciej; Klyachkin, Yurij; Houghton, Peter; Morris, Andrew J.; Vater, Axel; Klussmann, Sven; Kucia, Magdalena; Ratajczak, Mariusz Z.

    2013-01-01

    We observed that sphingosine-1-phosphate (S1P) and ceramide-1-phosphate (C1P) strongly enhance in vitro motility and adhesion of human rhabdomyosarcoma (RMS) cells. This effect was observed at physiological concentrations of both bioactive lipids, which are present in biological fluids, and is much stronger than the effects observed in response to known RMS pro-metastatic factors such as stromal derived factors-1 (SDF-1) or hepatocyte growth factor/scatter factor (HGF/SF). We also present novel evidence that the levels of S1P and C1P increase in several organs after γ-irradiation or chemotherapy, which indicates induction of an unwanted pro-metastatic environment related to treatment. Most importantly, we found that the metastasis of RMS cells in response to S1P can be effectively inhibited in vivo with the S1P-specific binder NOX-S93 that is based on a high affinity Spiegelmer. We propose that bioactive lipids play a previously underappreciated role in dissemination of RMS and the unwanted side effects of radio/chemotherapy by creating a pro-metastatic microenvironment. Therefore, an anti-metastatic treatment with specific S1P-binding scavenger such as NOX-S93 could become a part of standard radio/chemotherapy. PMID:23615526

  2. Choline phosphate potentiates sphingosine-1-phosphate-induced Raf-1 kinase activation dependent of Ras--phosphatidylinositol-3-kinase pathway.

    PubMed

    Lee, Michael; Han, Sang Seop

    2002-04-01

    In NIH3T3 cells, sphingosine-1-phosphate (S1P) caused a significant increase of Raf-1 kinase activity as early as 2 min. Interestingly, choline phosphate (ChoP) produced synergistic increase of S1P-stimulated Raf-1 kinase activation in the presence of ATP while showing additive effect in the absence of ATP. However, Raf-1 kinase activation induced by S1P decreased in the presence of ATP when applied alone. The overexpression of N-terminal fragment of Raf-1 (RfI) to inhibit Raf--Ras interaction caused the inhibition of S1P-induced Raf-1 kinase activation. Also, wortmannin, phosphatidylinositol-3-kinase (PI3K) inhibitor, exhibited inhibitory effects on S1P-induced activation of Raf-1 kinase. In addition, we demonstrated that the chemical antioxidant, N-acetylcysteine attenuated Raf-1 activation induced by S1P, suggesting that H(2)O(2) may be required for the signalling pathway leading to Raf-1 activation. This H(2)O(2)-induced Raf-1 kinase activation was also blocked by inhibition of Ras--PI3K signalling pathway using alpha-hydroxyfarnesylphosphonic acid and wortmannin. Taken together, these results indicate that S1P-induced Raf-1 kinase activation is mediated by H(2)O(2) stimulation of Ras--PI3K pathway, and is enhanced by ChoP in the presence of ATP.

  3. Critical Role of Spns2, a Sphingosine-1-Phosphate Transporter, in Lung Cancer Cell Survival and Migration

    PubMed Central

    Bradley, Eric; Dasgupta, Somsankar; Jiang, Xue; Zhao, Xiaying; Zhu, Gu; He, Qian; Dinkins, Michael; Bieberich, Erhard; Wang, Guanghu

    2014-01-01

    The sphingosine-1-phosphate (S1P) transporter Spns2 regulates myocardial precursor migration in zebrafish and lymphocyte trafficking in mice. However, its function in cancer has not been investigated. We show here that ectopic Spns2 expression induced apoptosis and its knockdown enhanced cell migration in non-small cell lung cancer (NSCLC) cells. Metabolically, Spns2 expression increased the extracellular S1P level while its knockdown the intracellular. Pharmacological inhibition of S1P synthesis abolished the augmented cell migration mediated by Spns2 knockdown, indicating that intracellular S1P plays a key role in this process. Cell signaling studies indicated that Spns2 expression impaired GSK-3β and Stat3 mediated pro-survival pathways. Conversely, these pathways were activated by Spns2 knockdown, which explains the increased cell migration since they are also crucial for migration. Alterations of Spns2 were found to affect several enzymes involved in S1P metabolism, including sphingosine kinases, S1P phosphatases, and S1P lyase 1. Genetically, Spns2 mRNA level was found to be reduced in advanced lung cancer (LC) patients as quantified by using a small scale qPCR array. These data show for the first time that Spns2 plays key roles in regulating the cellular functions in NSCLC cells, and that its down-regulation is a potential risk factor for LC. PMID:25330231

  4. Sphingosine 1-phosphate lyase enzyme assay using a BODIPY-labeled substrate

    SciTech Connect

    Bandhuvula, Padmavathi; Li Zaiguo; Bittman, Robert; Saba, Julie D.

    2009-03-06

    Sphingosine 1-phosphate lyase (SPL) is responsible for the irreversible catabolism of sphingosine 1-phosphate, which signals through five membrane receptors to mediate cell stress responses, angiogenesis, and lymphocyte trafficking. The standard assay for SPL activity utilizes a radioactive dihydrosphingosine 1-phosphate substrate and is expensive and cumbersome. In this study, we describe an SPL assay that employs an {omega}-labeled BODIPY-sphingosine 1-phosphate substrate, allowing fluorescent product detection by HPLC and incorporating advantages of the BODIPY fluorophore. The major aldehyde product is confirmed by reaction with 2,4-dinitrophenylhydrazine. The SPL-catalyzed reaction is linear over a 30 min time period and yields a K{sub m} of 35 {mu}M for BODIPY-sphingosine 1-phosphate.

  5. Sphingosine 1-phosphate lyase enzyme assay using a BODIPY-labeled substrate.

    PubMed

    Bandhuvula, Padmavathi; Li, Zaiguo; Bittman, Robert; Saba, Julie D

    2009-03-01

    Sphingosine 1-phosphate lyase (SPL) is responsible for the irreversible catabolism of sphingosine 1-phosphate, which signals through five membrane receptors to mediate cell stress responses, angiogenesis, and lymphocyte trafficking. The standard assay for SPL activity utilizes a radioactive dihydrosphingosine 1-phosphate substrate and is expensive and cumbersome. In this study, we describe an SPL assay that employs an omega-labeled BODIPY-sphingosine 1-phosphate substrate, allowing fluorescent product detection by HPLC and incorporating advantages of the BODIPY fluorophore. The major aldehyde product is confirmed by reaction with 2,4-dinitrophenylhydrazine. The SPL-catalyzed reaction is linear over a 30 min time period and yields a K(m) of 35 microM for BODIPY-sphingosine 1-phosphate.

  6. Thymic progenitor homing and lymphocyte homeostasis are linked via S1P-controlled expression of thymic P-selectin/CCL25

    PubMed Central

    Gossens, Klaus; Naus, Silvia; Corbel, Stephane Y.; Lin, Shujun; Rossi, Fabio M.V.; Kast, Jürgen

    2009-01-01

    Thymic T cell progenitor (TCP) importation is a periodic, gated event that is dependent on the expression of functional P-selectin ligands on TCPs. Occupancy of intrathymic TCP niches is believed to negatively regulate TCP importation, but the nature of this feedback mechanism is not yet resolved. We show that P-selectin and CCL25 are periodically expressed in the thymus and are essential parts of the thymic gate-keeping mechanism. Periodicity of thymic TCP receptivity and the size of the earliest intrathymic TCP pool were dependent on the presence of functional P-selectin ligand on TCPs. Furthermore, we show that the numbers of peripheral blood lymphocytes directly affected thymic P-selectin expression and TCP receptivity. We identified sphingosine-1-phosphate (S1P) as one feedback signal that could mediate influence of the peripheral lymphocyte pool on thymic TCP receptivity. Our findings suggest a model whereby thymic TCP importation is controlled by both early thymic niche occupancy and the peripheral lymphocyte pool via S1P. PMID:19289576

  7. Evidence for a link between histone deacetylation and Ca²+ homoeostasis in sphingosine-1-phosphate lyase-deficient fibroblasts.

    PubMed

    Ihlefeld, Katja; Claas, Ralf Frederik; Koch, Alexander; Pfeilschifter, Josef M; Meyer Zu Heringdorf, Dagmar

    2012-11-01

    Embryonic fibroblasts from S1P (sphingosine-1-phosphate) lyase-deficient mice [Sgpl1-/- MEFs (mouse embryonic fibroblasts)] are characterized by intracellular accumulation of S1P, elevated cytosolic [Ca2+]i and enhanced Ca2+ storage. Since S1P, produced by sphingosine kinase 2 in the nucleus of MCF-7 cells, inhibited HDACs (histone deacetylases) [Hait, Allegood, Maceyka, Strub, Harikumar, Singh, Luo, Marmorstein, Kordula, Milstein et al. (2009) Science 325, 1254-1257], in the present study we analysed whether S1P accumulated in the nuclei of S1P lyase-deficient MEFs and caused HDAC inhibition. Interestingly, nuclear concentrations of S1P were disproportionally elevated in Sgpl1-/- MEFs. HDAC activity was reduced, acetylation of histone 3-Lys9 was increased and the HDAC-regulated gene p21 cyclin-dependent kinase inhibitor was up-regulated in these cells. Furthermore, the expression of HDAC1 and HDAC3 was reduced in Sgpl1-/- MEFs. In wild-type MEFs, acetylation of histone 3-Lys9 was increased by the S1P lyase inhibitor 4-deoxypyridoxine. The non-specific HDAC inhibitor trichostatin A elevated basal [Ca2+]i and enhanced Ca2+ storage, whereas the HDAC1/2/3 inhibitor MGCD0103 elevated basal [Ca2+]i without influence on Ca2+ storage in wild-type MEFs. Overexpression of HDAC1 or HDAC2 reduced the elevated basal [Ca2+]i in Sgpl1-/- MEFs. Taken together, S1P lyase-deficiency was associated with elevated nuclear S1P levels, reduced HDAC activity and down-regulation of HDAC isoenzymes. The decreased HDAC activity in turn contributed to the dysregulation of Ca2+ homoeostasis, particularly to the elevated basal [Ca2+]i, in Sgpl1-/- MEFs.

  8. Sphingosine 1-phosphate and its carrier apolipoprotein M in human sepsis and in Escherichia coli sepsis in baboons.

    PubMed

    Frej, Cecilia; Linder, Adam; Happonen, Kaisa E; Taylor, Fletcher B; Lupu, Florea; Dahlbäck, Björn

    2016-06-01

    Sphingosine 1-phosphate (S1P) is an important regulator of vascular integrity and immune cell migration, carried in plasma by high-density lipoprotein (HDL)-associated apolipoprotein M (apoM) and by albumin. In sepsis, the protein and lipid composition of HDL changes dramatically. The aim of this study was to evaluate changes in S1P and its carrier protein apoM during sepsis. For this purpose, plasma samples from both human sepsis patients and from an experimental Escherichia coli sepsis model in baboons were used. In the human sepsis cohort, previously studied for apoM, plasma demonstrated disease-severity correlated decreased S1P levels, the profile mimicking that of plasma apoM. In the baboons, a similar disease-severity dependent decrease in plasma levels of S1P and apoM was observed. In the lethal E. coli baboon sepsis, S1P decreased already within 6-8 hrs, whereas the apoM decrease was seen later at 12-24 hrs. Gel filtration chromatography of plasma from severe human or baboon sepsis on Superose 6 demonstrated an almost complete loss of S1P and apoM in the HDL fractions. S1P plasma concentrations correlated with the platelet count but not with erythrocytes or white blood cells. The liver mRNA levels of apoM and apoA1 decreased strongly upon sepsis induction and after 12 hr both were almost completely lost. In conclusion, during septic challenge, the plasma levels of S1P drop to very low levels. Moreover, the liver synthesis of apoM decreases severely and the plasma levels of apoM are reduced. Possibly, the decrease in S1P contributes to the decreased endothelial barrier function observed in sepsis. PMID:26990127

  9. MECHANISMS OF SPHINGOSINE-1-PHOSPHATE INDUCED AKT DEPENDENT SMOOTH MUSCLE CELL MIGRATION

    PubMed Central

    Roztocil, Elisa; Nicholl, Suzanne M.; Davies, Mark G.

    2008-01-01

    Background Sphingosine-1-phosphate (S-1-P) is a bioactive sphingolipid released from activated platelets, which stimulates migration of vascular smooth muscle cells (VSMC) in vitro. S-1-P will activate akt, which can regulate multiple cellular functions including cell migration. Akt activation is downstream of phosphatidyl-inositol 3′ kinase (PI3-K) and Phosphoinositide-dependent protein kinase-1 (PDK1). Objective To examine the regulation of akt signaling during smooth muscle cell migration in response to S-1-P. Methods Murine arterial SMCs were cultured in vitro. Linear wound and Boyden microchemotaxis assays of migration were performed in the presence of S-1-P with and without an akt inhibitor (aktI). Assays were performed for PI3-K, PDK1, akt and GSK3β activation in the presence of various inhibitors and after transfection with the Gβγ inhibitor. βARKCT. Results S-1-P induced time dependent PI3-K, PDK1 and akt activation. The migratory responses in both assays to S-1-P were blocked by akt inhibitor (aktI). Activation of akt and dephosphorylation of its downstream kinase, GSK3 β, were inhibited by aktI. Inhibition of PI3-K with LY294002 significantly reduced both PI3-K and akt activation. Inhibition of G βγ inhibited akt activation through a reduction in both PI3-K and PDK1 activation. While inhibition of the ras with manumycin A had no effect, inhibition of rho with C3 limited both PI3K and akt activation. PDK1 responses were unchanged by inhibition of GTPases. Inhibition of reactive oxygen species generation with N-acetylcysteine and of EGFR with AG1478 inhibited PDK1 activation in response to S-1-P. Conclusion S-1-P mediated migration is akt dependent. S-1-P mediated akt phosphorylation is controlled by G βγ dependent, PI3-K activation, which requires the GTPase rho and Gβγ. PDK1 activation requires Gβγ reactive oxygen species generation and EGFR activation. PMID:19081473

  10. Increased sphingosine-1-phosphate improves muscle regeneration in acutely injured mdx mice

    PubMed Central

    2013-01-01

    Background Presently, there is no effective treatment for the lethal muscle wasting disease Duchenne muscular dystrophy (DMD). Here we show that increased sphingosine-1-phoshate (S1P) through direct injection or via the administration of the small molecule 2-acetyl-4(5)-tetrahydroxybutyl imidazole (THI), an S1P lyase inhibitor, has beneficial effects in acutely injured dystrophic muscles of mdx mice. Methods We treated mdx mice with and without acute injury and characterized the histopathological and functional effects of increasing S1P levels. We also tested exogenous and direct administration of S1P on mdx muscles to examine the molecular pathways under which S1P promotes regeneration in dystrophic muscles. Results Short-term treatment with THI significantly increased muscle fiber size and extensor digitorum longus (EDL) muscle specific force in acutely injured mdx limb muscles. In addition, the accumulation of fibrosis and fat deposition, hallmarks of DMD pathology and impaired muscle regeneration, were lower in the injured muscles of THI-treated mdx mice. Furthermore, increased muscle force was observed in uninjured EDL muscles with a longer-term treatment of THI. Such regenerative effects were linked to the response of myogenic cells, since intramuscular injection of S1P increased the number of Myf5nlacz/+ positive myogenic cells and newly regenerated myofibers in injured mdx muscles. Intramuscular injection of biotinylated-S1P localized to muscle fibers, including newly regenerated fibers, which also stained positive for S1P receptor 1 (S1PR1). Importantly, plasma membrane and perinuclear localization of phosphorylated S1PR1 was observed in regenerating muscle fibers of mdx muscles. Intramuscular increases of S1P levels, S1PR1 and phosphorylated ribosomal protein S6 (P-rpS6), and elevated EDL muscle specific force, suggest S1P promoted the upregulation of anabolic pathways that mediate skeletal muscle mass and function. Conclusions These data show that S1P is

  11. Cross talk between MMP2-Spm-Cer-S1P and ERK1/2 in proliferation of pulmonary artery smooth muscle cells under angiotensin II stimulation.

    PubMed

    Chowdhury, Animesh; Sarkar, Jaganmay; Pramanik, Pijush Kanti; Chakraborti, Tapati; Chakraborti, Sajal

    2016-08-01

    The aim of the present study is to establish the mechanism associated with the proliferation of PASMCs under ANG II stimulation. The results showed that treatment of PASMCs with ANG II induces an increase in cell proliferation and 100 nM was the optimum concentration for maximum increase in proliferation of the cells. Pretreatment of the cells with AT1, but not AT2, receptor antagonist inhibited ANG II induced cell proliferation. Pretreatment with pharmacological and genetic inhibitors of sphingomyelinase (SMase) and sphingosine kinase (SPHK) prevented ANG II-induced cell proliferation. ANG II has also been shown to induce SMase activity, SPHK phosphorylation and S1P production. In addition, ANG II caused an increase in proMMP-2 expression and activation, ERK1/2 phosphorylation and NADPH oxidase activation. Upon inhibition of MMP-2, SMase activity and S1P level were curbed leading to inhibition of cell proliferation. SPHK was phosphorylated by ERK1/2 during ET-1 stimulation of the cells. ANG II-induced ERK1/2 phosphorylation and proMMP-2 expression and activation in the cells were abrogated upon inhibition of NADPH oxidase activity. Overall, NADPH oxidase plays an important role in proMMP-2 expression and activation and that MMP-2 mediated SMC proliferation occurs through the involvement of Spm-Cer-S1P signaling axis under ANG II stimulation of PASMCs. PMID:27210740

  12. Polydatin attenuates AGEs-induced upregulation of fibronectin and ICAM-1 in rat glomerular mesangial cells and db/db diabetic mice kidneys by inhibiting the activation of the SphK1-S1P signaling pathway.

    PubMed

    Chen, Cheng; Huang, Kaipeng; Hao, Jie; Huang, Junying; Yang, Zhiying; Xiong, Fengxiao; Liu, Peiqing; Huang, Heqing

    2016-05-15

    We previously demonstrated that activation of sphingosine kinase 1 (SphK1)- sphingosine 1- phosphate (S1P) signaling pathway by high glucose (HG) plays a pivotal role in increasing the expression of fibronectin (FN), an important fibrotic component, by promoting the DNA-binding activity of transcription factor activator protein 1 (AP-1) in glomerular mesangial cells (GMCs) under diabetic conditions. As a multi-target anti-oxidative drug, polydatin (PD) has been shown to have renoprotective effects on experimental diabetes. However, whether PD could resist diabetic nephropathy (DN) by regulating SphK1-S1P signaling pathway needs further investigation. Here, we found that PD significantly reversed the upregulated FN and ICAM-1 expression in GMCs exposed to AGEs. Simultaneously, PD dose-dependently inhibited SphK1 levels at the protein expression and kinase activity and attenuated S1P production under AGEs treatment conditions. In addition, PD reduced SphK activity in GMCs transfected with wild-type SphK(WT) plasmid and significantly suppressed SphK1-mediated increase of FN and ICAM-1 levels under normal conditions. Furthermore, we found that the AGEs-induced upregulation of phosphorylation of c-Jun at Ser63 and Ser73 and c-Fos at Ser32, DNA-binding activity and transcriptional activity of AP-1 were blocked by PD. In comparison with db/db model group, PD treatment suppressed SphK1 levels (mRNA, protein expression, and activity) and S1P production, reversed the upregulation of FN, ICAM-1, c-Jun, and c-Fos in the kidney tissues of diabetic mice, and finally ameliorated renal injury in db/db mice. These findings suggested that the downregulation of SphK1-S1P signaling pathway is probably a novel mechanism by which PD suppressed AGEs-induced FN and ICAM-1 expression and improved renal dysfunction of diabetic models. PMID:26948947

  13. Interstitial Fluid Sphingosine-1-Phosphate in Murine Mammary Gland and Cancer and Human Breast Tissue and Cancer Determined by Novel Methods.

    PubMed

    Nagahashi, Masayuki; Yamada, Akimitsu; Miyazaki, Hiroshi; Allegood, Jeremy C; Tsuchida, Junko; Aoyagi, Tomoyoshi; Huang, Wei-Ching; Terracina, Krista P; Adams, Barbara J; Rashid, Omar M; Milstien, Sheldon; Wakai, Toshifumi; Spiegel, Sarah; Takabe, Kazuaki

    2016-06-01

    The tumor microenvironment is a determining factor for cancer biology and progression. Sphingosine-1-phosphate (S1P), produced by sphingosine kinases (SphKs), is a bioactive lipid mediator that regulates processes important for cancer progression. Despite its critical roles, the levels of S1P in interstitial fluid (IF), an important component of the tumor microenvironment, have never previously been measured due to a lack of efficient methods for collecting and quantifying IF. The purpose of this study is to clarify the levels of S1P in the IF from murine mammary glands and its tumors utilizing our novel methods. We developed an improved centrifugation method to collect IF. Sphingolipids in IF, blood, and tissue samples were measured by mass spectrometry. In mice with a deletion of SphK1, but not SphK2, levels of S1P in IF from the mammary glands were greatly attenuated. Levels of S1P in IF from mammary tumors were reduced when tumor growth was suppressed by oral administration of FTY720/fingolimod. Importantly, sphingosine, dihydro-sphingosine, and S1P levels, but not dihydro-S1P, were significantly higher in human breast tumor tissue IF than in the normal breast tissue IF. To our knowledge, this is the first reported S1P IF measurement in murine normal mammary glands and mammary tumors, as well as in human patients with breast cancer. S1P tumor IF measurement illuminates new aspects of the role of S1P in the tumor microenvironment.

  14. Sorafenib inhibits endogenous and IL-6/S1P induced JAK2-STAT3 signaling in human neuroblastoma, associated with growth suppression and apoptosis.

    PubMed

    Yang, Fan; Jove, Veronica; Buettner, Ralf; Xin, Hong; Wu, Jun; Wang, Yan; Nam, Sangkil; Xu, Yibing; Ara, Tasnim; DeClerck, Yves A; Seeger, Robert; Yu, Hua; Jove, Richard

    2012-05-01

    Neuroblastoma is the most common extracranial solid tumor in the pediatric population. Sorafenib (Nexavar), a multikinase inhibitor, blocks cell proliferation and induces apoptosis in certain types of cancers. Here, we tested antitumor effects of sorafenib (≤ 10 µM) on four human neuroblastoma cell lines, CHLA255, CHLA171, CHLA90 and SK-N-AS. Sorafenib inhibited cell proliferation and induced apoptosis of neuroblastoma tumor cells in a dose-dependent manner. Sorafenib inhibited phosphorylation of Signal Transducer and Activator of Transcription 3 (STAT3) proteins at Tyr705 in these cells, associated with inhibition of phosphorylated JAK2, an upstream kinase that mediates STAT3 phosphorylation. Expression of a constitutively-activated STAT3 mutant (pSTAT3-C) partially blocked the antitumor effects of sorafenib on neuroblastoma cells. Sorafenib also inhibited the phosphorylation of STAT3 induced by IL-6 and sphingosine-1-phosphate (S1P), a recently identified regulator for STAT3, in these tumor cells. Moreover, sorafenib downregulated phosphorylation of MAPK (p44/42) in neuroblastoma cells, consistent with inhibition of their upstream regulators MEK1/2. Sorafenib inhibited expression of cyclin E, cyclin D1/D2/D3, key regulators for cell cycle, and the antiapoptotic proteins Mcl-1 and survivin. Finally, sorafenib suppressed the growth of human neuroblastoma cells in a mouse xenograft model. Taken together, these findings suggest the potential use of sorafenib for the treatment of pediatric neuroblastomas.

  15. Hantaviruses direct endothelial cell permeability by sensitizing cells to the vascular permeability factor VEGF, while angiopoietin 1 and sphingosine 1-phosphate inhibit hantavirus-directed permeability.

    PubMed

    Gavrilovskaya, Irina N; Gorbunova, Elena E; Mackow, Natalie A; Mackow, Erich R

    2008-06-01

    Hantaviruses infect human endothelial cells and cause two vascular permeability-based diseases: hemorrhagic fever with renal syndrome and hantavirus pulmonary syndrome. Hantavirus infection alone does not permeabilize endothelial cell monolayers. However, pathogenic hantaviruses inhibit the function of alphav beta3 integrins on endothelial cells, and hemorrhagic disease and vascular permeability deficits are consequences of dysfunctional beta3 integrins that normally regulate permeabilizing vascular endothelial growth factor (VEGF) responses. Here we show that pathogenic Hantaan, Andes, and New York-1 hantaviruses dramatically enhance the permeability of endothelial cells in response to VEGF, while the nonpathogenic hantaviruses Prospect Hill and Tula have no effect on endothelial cell permeability. Pathogenic hantaviruses directed endothelial cell permeability 2 to 3 days postinfection, coincident with pathogenic hantavirus inhibition of alphav beta3 integrin functions, and hantavirus-directed permeability was inhibited by antibodies to VEGF receptor 2 (VEGFR2). These studies demonstrate that pathogenic hantaviruses, similar to alphav beta3 integrin-deficient cells, specifically enhance VEGF-directed permeabilizing responses. Using the hantavirus permeability assay we further demonstrate that the endothelial-cell-specific growth factor angiopoietin 1 (Ang-1) and the platelet-derived lipid mediator sphingosine 1-phosphate (S1P) inhibit hantavirus directed endothelial cell permeability at physiologic concentrations. These results demonstrate the utility of a hantavirus permeability assay and rationalize the testing of Ang-1, S1P, and antibodies to VEGFR2 as potential hantavirus therapeutics. The central importance of beta3 integrins and VEGF responses in vascular leak and hemorrhagic disease further suggest that altering beta3 or VEGF responses may be a common feature of additional viral hemorrhagic diseases. As a result, our findings provide a potential mechanism

  16. Human neural progenitors express functional lysophospholipid receptors that regulate cell growth and morphology

    PubMed Central

    Hurst, Jillian H; Mumaw, Jennifer; Machacek, David W; Sturkie, Carla; Callihan, Phillip; Stice, Steve L; Hooks, Shelley B

    2008-01-01

    Background Lysophospholipids regulate the morphology and growth of neurons, neural cell lines, and neural progenitors. A stable human neural progenitor cell line is not currently available in which to study the role of lysophospholipids in human neural development. We recently established a stable, adherent human embryonic stem cell-derived neuroepithelial (hES-NEP) cell line which recapitulates morphological and phenotypic features of neural progenitor cells isolated from fetal tissue. The goal of this study was to determine if hES-NEP cells express functional lysophospholipid receptors, and if activation of these receptors mediates cellular responses critical for neural development. Results Our results demonstrate that Lysophosphatidic Acid (LPA) and Sphingosine-1-phosphate (S1P) receptors are functionally expressed in hES-NEP cells and are coupled to multiple cellular signaling pathways. We have shown that transcript levels for S1P1 receptor increased significantly in the transition from embryonic stem cell to hES-NEP. hES-NEP cells express LPA and S1P receptors coupled to Gi/o G-proteins that inhibit adenylyl cyclase and to Gq-like phospholipase C activity. LPA and S1P also induce p44/42 ERK MAP kinase phosphorylation in these cells and stimulate cell proliferation via Gi/o coupled receptors in an Epidermal Growth Factor Receptor (EGFR)- and ERK-dependent pathway. In contrast, LPA and S1P stimulate transient cell rounding and aggregation that is independent of EGFR and ERK, but dependent on the Rho effector p160 ROCK. Conclusion Thus, lysophospholipids regulate neural progenitor growth and morphology through distinct mechanisms. These findings establish human ES cell-derived NEP cells as a model system for studying the role of lysophospholipids in neural progenitors. PMID:19077254

  17. Mechanism of Folding and Activation of Subtilisin Kexin Isozyme-1 (SKI-1)/Site-1 Protease (S1P).

    PubMed

    da Palma, Joel Ramos; Cendron, Laura; Seidah, Nabil Georges; Pasquato, Antonella; Kunz, Stefan

    2016-01-29

    The proprotein convertase subtilisin kexin isozyme-1 (SKI-1)/site-1 protease (S1P) is implicated in lipid homeostasis, the unfolded protein response, and lysosome biogenesis. The protease is further hijacked by highly pathogenic emerging viruses for the processing of their envelope glycoproteins. Zymogen activation of SKI-1/S1P requires removal of an N-terminal prodomain, by a multistep process, generating the mature enzyme. Here, we uncover a modular structure of the human SKI-1/S1P prodomain and define its function in folding and activation. We provide evidence that the N-terminal AB fragment of the prodomain represents an autonomous structural and functional unit that is necessary and sufficient for folding and partial activation. In contrast, the C-terminal BC fragment lacks a defined structure but is crucial for autoprocessing and full catalytic activity. Phylogenetic analysis revealed that the sequence of the AB domain is highly conserved, whereas the BC fragment shows considerable variation and seems even absent in some species. Notably, SKI-1/S1P of arthropods, like the fruit fly Drosophila melanogaster, contains a shorter prodomain comprised of full-length AB and truncated BC regions. Swapping the prodomain fragments between fly and human resulted in a fully mature and active SKI-1/S1P chimera. Our study suggests that primordial SKI-1/S1P likely contained a simpler prodomain consisting of the highly conserved AB fragment that represents an independent folding unit. The BC region appears as a later evolutionary acquisition, possibly allowing more subtle fine-tuning of the maturation process.

  18. Early Double-Negative Thymocyte Export in Trypanosoma cruzi Infection Is Restricted by Sphingosine Receptors and Associated with Human Chagas Disease

    PubMed Central

    Lepletier, Ailin; de Almeida, Liliane; Santos, Leonardo; da Silva Sampaio, Luzia; Paredes, Bruno; González, Florencia Belén; Freire-de-Lima, Célio Geraldo; Beloscar, Juan; Bottasso, Oscar; Einicker-Lamas, Marcelo; Pérez, Ana Rosa; Savino, Wilson; Morrot, Alexandre

    2014-01-01

    The protozoan parasite Trypanosoma cruzi is able to target the thymus and induce alterations of the thymic microenvironmental and lymphoid compartments. Acute infection results in severe atrophy of the organ and early release of immature thymocytes into the periphery. To date, the pathophysiological effects of thymic changes promoted by parasite-inducing premature release of thymocytes to the periphery has remained elusive. Herein, we show that sphingosine-1-phosphate (S1P), a potent mediator of T cell chemotaxis, plays a role in the exit of immature double-negative thymocytes in experimental Chagas disease. In thymuses from T. cruzi-infected mice we detected reduced transcription of the S1P kinase 1 and 2 genes related to S1P biosynthesis, together with increased transcription of the SGPL1 sphingosine-1-lyase gene, whose product inactivates S1P. These changes were associated with reduced intrathymic levels of S1P kinase activity. Interestingly, double-negative thymocytes from infected animals expressed high levels of the S1P receptor during infection, and migrated to lower levels of S1P. Moreover, during T. cruzi infection, this thymocyte subset expresses high levels of IL-17 and TNF-α cytokines upon polyclonal stimulation. In vivo treatment with the S1P receptor antagonist FTY720 resulted in recovery the numbers of double-negative thymocytes in infected thymuses to physiological levels. Finally, we showed increased numbers of double-negative T cells in the peripheral blood in severe cardiac forms of human Chagas disease. PMID:25330249

  19. Conversion of Glucose-1-Phosphate to 3-Keto-glucose-1-phosphate by Cells of Agrobacterium tumefaciens

    PubMed Central

    Fukui, Sakuzo

    1969-01-01

    Incubation of resting cells of Agrobacterium tumefaciens with glucose-1-phosphate resulted in the accumulation of a new sugar phosphate in the suspending medium. Approximately 80% of the glucose-1-phosphate consumed was converted to the new compound, which was identified as α-d-ribo-hexopyranosyl-3-ulose-1-phosphate (3-ketoglucose-1-phosphate). Both utilization of glucose-1-phosphate and accumulation of 3-ketoglucose-1-phosphate were inhibited by 2,4-dinitrophenol, polymyxin, and d-glucose, which are inhibitors of the glucoside transport system of this bacterium but are not inhibitors of d-glucoside-3-dehydrogenase, which is the 3-ketoglucose-1-phosphate-forming enzyme. Consequently, it was concluded that glucose-1-phosphate penetrates into intracellular space by means of an active transport system. The glucose-1-phosphate is converted to 3-ketoglucose-1-phosphate by d-glucoside-3-dehydrogenase, and the 3-ketoglucose-1-phosphate formed reaches the extracellular space by passing through the surface layer of the bacterium. PMID:4304223

  20. SKI-1/S1P inhibition: a promising surrogate to statins to block hepatitis C virus replication.

    PubMed

    Blanchet, Matthieu; Seidah, Nabil G; Labonté, Patrick

    2012-08-01

    Hepatitis C virus (HCV) is often associated with steatosis, cirrhosis and hepatocellular carcinoma (HCC). Statins (HMG-CoAR inhibitors) have been shown to exert an antiviral effect in vitro, principally on replicon harboring cells, but the effect of their use alone in vivo remains controversial. In clinical trials, when used in combination with the standards of care (SOC), they led to an increased proportion of sustained virological responder (SVR). Here we investigated the implication of SKI-1/S1P, a master lipogenic pathways regulator upstream of HMG-CoAR, on different steps of HCV life cycle. We compared the HCV antiviral effect of the most potent SKI-1/S1P small molecule inhibitor (PF-429242) with a set of two statins on different steps of the viral life cycle, and showed that SKI-1/S1P inhibitor blocked HCVcc (strain JFH-1) RNA replication (EC(50)= 5.8 μM) more efficiently than statins. Moreover, we showed that PF-429242 could reduce lipid droplets accumulation in Huh7 cells. Interestingly, PF-429242 dramatically reduced infectious particles production (EC(90)= 4.8 μM). Such inhibition could not be achieved with statins. SKI-1/S1P activity is thus essential for viral production and its inhibition should be considered for antiviral drug development. PMID:22626636

  1. Quantification of sphingosine 1-phosphate by validated LC-MS/MS method revealing strong correlation with apolipoprotein M in plasma but not in serum due to platelet activation during blood coagulation.

    PubMed

    Frej, Cecilia; Andersson, Anders; Larsson, Benny; Guo, Li Jun; Norström, Eva; Happonen, Kaisa E; Dahlbäck, Björn

    2015-11-01

    Sphingosine 1-phosphate (S1P) is a signalling sphingolipid affecting multiple cellular functions of vascular and immune systems. It circulates at submicromolar levels bound to HDL-associated apolipoprotein M (apoM) or to albumin. S1P in blood is mainly produced by platelets and erythrocytes, making blood sampling for S1P quantification delicate. Standardisation of sampling is thereby of great importance to obtain robust data. By optimising and characterising the extraction procedure and the LC-MS/MS analysis, we have developed and validated a highly specific and sensitive method for S1P quantification. Blood was collected from healthy individuals (n = 15) to evaluate the effects of differential blood sampling on S1P levels. To evaluate correlation between S1P and apoM in different types of plasma and serum, apoM was measured by ELISA. The method showed good accuracy and precision in the range of 0.011 to 0.9 μM with less than 0.07 % carryover. We found that the methanol precipitation used to extract S1P co-extracted apoM and several other HDL-proteins from plasma. The platelet-associated S1P was released during coagulation, thus increasing the S1P concentration to double in serum as compared to that in plasma. Gel filtration chromatography revealed that the platelet-released S1P was mainly bound to albumin. This explains why the strong correlation between S1P and apoM levels in plasma is lost upon the clotting process and hence not observed in serum. We have developed, characterised and validated an efficient, highly sensitive and specific method for the quantification of S1P in biological material.

  2. Ceramide and ceramide 1-phosphate in health and disease

    PubMed Central

    2010-01-01

    Sphingolipids are essential components of cell membranes, and many of them regulate vital cell functions. In particular, ceramide plays crucial roles in cell signaling processes. Two major actions of ceramides are the promotion of cell cycle arrest and the induction of apoptosis. Phosphorylation of ceramide produces ceramide 1-phosphate (C1P), which has opposite effects to ceramide. C1P is mitogenic and has prosurvival properties. In addition, C1P is an important mediator of inflammatory responses, an action that takes place through stimulation of cytosolic phospholipase A2, and the subsequent release of arachidonic acid and prostaglandin formation. All of the former actions are thought to be mediated by intracellularly generated C1P. However, the recent observation that C1P stimulates macrophage chemotaxis implicates specific plasma membrane receptors that are coupled to Gi proteins. Hence, it can be concluded that C1P has dual actions in cells, as it can act as an intracellular second messenger to promote cell survival, or as an extracellular receptor agonist to stimulate cell migration. PMID:20137073

  3. Tumor Necrosis Factor/Sphingosine-1-Phosphate Signaling Augments Resistance Artery Myogenic Tone in Diabetes.

    PubMed

    Sauvé, Meghan; Hui, Sonya K; Dinh, Danny D; Foltz, Warren D; Momen, Abdul; Nedospasov, Sergei A; Offermanns, Stefan; Husain, Mansoor; Kroetsch, Jeffrey T; Lidington, Darcy; Bolz, Steffen-Sebastian

    2016-07-01

    Diabetes strongly associates with microvascular complications that ultimately promote multiorgan failure. Altered myogenic responsiveness compromises tissue perfusion, aggravates hypertension, and sets the stage for later permanent structural changes to the microcirculation. We demonstrate that skeletal muscle resistance arteries isolated from patients with diabetes have augmented myogenic tone, despite reasonable blood glucose control. To understand the mechanisms, we titrated a standard diabetes mouse model (high-fat diet plus streptozotocin [HFD/STZ]) to induce a mild increase in blood glucose levels. HFD/STZ treatment induced a progressive myogenic tone augmentation in mesenteric and olfactory cerebral arteries; neither HFD nor STZ alone had an effect on blood glucose or resistance artery myogenic tone. Using gene deletion models that eliminate tumor necrosis factor (TNF) or sphingosine kinase 1, we demonstrate that vascular smooth muscle cell TNF drives the elevation of myogenic tone via enhanced sphingosine-1-phosphate (S1P) signaling. Therapeutically antagonizing TNF (etanercept) or S1P (JTE013) signaling corrects this defect. Our investigation concludes that vascular smooth muscle cell TNF augments resistance artery myogenic vasoconstriction in a diabetes model that induces a small elevation of blood glucose. Our data demonstrate that microvascular reactivity is an early disease marker and advocate establishing therapies that strategically target the microcirculation. PMID:27207546

  4. Extracellular Matrix Rigidity-dependent Sphingosine-1-phosphate Secretion Regulates Metastatic Cancer Cell Invasion and Adhesion

    PubMed Central

    Ko, Panseon; Kim, Daehwan; You, Eunae; Jung, Jangho; Oh, Somi; Kim, Jaehyun; Lee, Kwang-Ho; Rhee, Sangmyung

    2016-01-01

    Dynamic interaction between cancer cells and the surrounding microenvironment is critical for cancer progression via changes in cellular behavior including alteration of secreted molecules. However, the molecular mechanisms underlying the influence exerted by the cancer microenvironment on secretion of molecules during cancer progression remain largely unknown. In this study, we report that secretion of spingsine-1-phosphate (S1P) and its regulator, SphK1 expression is dependent of the substrate rigidity, which is critical for the balance between cancer cell invasion and adhesion. Conditioned media (CM) of MDA-MB-231, an aggressive breast cancer cell obtained from soft substrate (~0.5 kPa) induced chemo-attractive invasion, while CM obtained from stiff substrate (~2.5 kPa) increased cell adhesion instead. We found that the expression of SphK1 is upregulated in the stiff substrate, resulting in an increase in S1P levels in the CM. We also found that upregulation of SphK1 expression in the stiff substrate is dominant in metastatic cancer cells but not in primary cancer cells. These results suggest that alterations in the mechanical environment of the ECM surrounding the tumor cells actively regulate cellular properties such as secretion, which in turn, may contribute to cancer progression. PMID:26877098

  5. Sphingosine-1-phosphate mediates proliferation maintaining the multipotency of human adult bone marrow and adipose tissue-derived stem cells.

    PubMed

    He, Xiaoli; H'ng, Shiau-Chen; Leong, David T; Hutmacher, Dietmar W; Melendez, Alirio J

    2010-08-01

    High renewal and maintenance of multipotency of human adult stem cells (hSCs), are a prerequisite for experimental analysis as well as for potential clinical usages. The most widely used strategy for hSC culture and proliferation is using serum. However, serum is poorly defined and has a considerable degree of inter-batch variation, which makes it difficult for large-scale mesenchymal stem cells (MSCs) expansion in homogeneous culture conditions. Moreover, it is often observed that cells grown in serum-containing media spontaneously differentiate into unknown and/or undesired phenotypes. Another way of maintaining hSC development is using cytokines and/or tissue-specific growth factors; this is a very expensive approach and can lead to early unwanted differentiation. In order to circumvent these issues, we investigated the role of sphingosine-1-phosphate (S1P), in the growth and multipotency maintenance of human bone marrow and adipose tissue-derived MSCs. We show that S1P induces growth, and in combination with reduced serum, or with the growth factors FGF and platelet-derived growth factor-AB, S1P has an enhancing effect on growth. We also show that the MSCs cultured in S1P-supplemented media are able to maintain their differentiation potential for at least as long as that for cells grown in the usual serum-containing media. This is shown by the ability of cells grown in S1P-containing media to be able to undergo osteogenic as well as adipogenic differentiation. This is of interest, since S1P is a relatively inexpensive natural product, which can be obtained in homogeneous high-purity batches: this will minimize costs and potentially reduce the unwanted side effects observed with serum. Taken together, S1P is able to induce proliferation while maintaining the multipotency of different human stem cells, suggesting a potential for S1P in developing serum-free or serum-reduced defined medium for adult stem cell cultures.

  6. Tumor suppressor PRSS8 targets Sphk1/S1P/Stat3/Akt signaling in colorectal cancer

    PubMed Central

    Wang, Qian; Li, Zexin; Yang, Yiqiong; Chen, Zhiguo; Wang, Jianguo; Zhao, Weixing; Zhang, Huijuan; Chen, Jiwang; Dong, Huali; Shen, Kui; Diamond, Alan M.; Yang, Wancai

    2016-01-01

    PRSS8 is a membrane-anchored serine protease prostasin and has been shown an association with carcinogenesis. Herein we found that PRSS8 expression was significantly reduced in colorectal adenomas and adenocarcinomas. The decreased PRSS8 was well correlated with clinical stages, poor differentiation and shorter survival time of colorectal cancer. Furthermore, increase of PRSS8 led to the inhibition of colorectal cancer cell proliferation, knockdown of PRSS8 accelerated cell proliferation in vitro, and overexpressing PRSS8 retarded cancer cell growth in nude mice. Mechanistic studies revealed that PRSS8 inhibited Sphk1/S1P/Stat3/Akt signaling pathway, in terms of inverse association between PRSS8 and Sphk1 in human colorectal cancers and in Sphk1-/− mice. In conclusion, PRSS8 acts as a tumor suppressor by inhibiting Sphk1/S1P/Stat3/Akt signaling pathway, and could be used as a biomarker to monitor colorectal carcinogenesis and predict outcomes. PMID:27050145

  7. Tumor suppressor PRSS8 targets Sphk1/S1P/Stat3/Akt signaling in colorectal cancer.

    PubMed

    Bao, Yonghua; Li, Kai; Guo, Yongchen; Wang, Qian; Li, Zexin; Yang, Yiqiong; Chen, Zhiguo; Wang, Jianguo; Zhao, Weixing; Zhang, Huijuan; Chen, Jiwang; Dong, Huali; Shen, Kui; Diamond, Alan M; Yang, Wancai

    2016-05-01

    PRSS8 is a membrane-anchored serine protease prostasin and has been shown an association with carcinogenesis. Herein we found that PRSS8 expression was significantly reduced in colorectal adenomas and adenocarcinomas. The decreased PRSS8 was well correlated with clinical stages, poor differentiation and shorter survival time of colorectal cancer. Furthermore, increase of PRSS8 led to the inhibition of colorectal cancer cell proliferation, knockdown of PRSS8 accelerated cell proliferation in vitro, and overexpressing PRSS8 retarded cancer cell growth in nude mice. Mechanistic studies revealed that PRSS8 inhibited Sphk1/S1P/Stat3/Akt signaling pathway, in terms of inverse association between PRSS8 and Sphk1 in human colorectal cancers and in Sphk1-/- mice. In conclusion, PRSS8 acts as a tumor suppressor by inhibiting Sphk1/S1P/Stat3/Akt signaling pathway, and could be used as a biomarker to monitor colorectal carcinogenesis and predict outcomes. PMID:27050145

  8. Berberine Preconditioning Protects Neurons Against Ischemia via Sphingosine-1-Phosphate and Hypoxia-Inducible Factor-1[Formula: see text].

    PubMed

    Zhang, Qichun; Bian, Huimin; Guo, Liwei; Zhu, Huaxu

    2016-01-01

    Berberine exerts neuroprotective and modulates hypoxia inducible factor-1-alpha (HIF-1[Formula: see text]. Based on the role of HIF-1[Formula: see text] in hypoxia preconditioning and association between HIF-1[Formula: see text] and sphingosine-1-phosphate (S1P), we hypothesized that berberine preconditioning (BP) would ameliorate the cerebral injury induced by ischemia through activating the system of HIF-1[Formula: see text] and S1P. Adult male rats with middle cerebral artery occlusion (MCAO) and rat primary cortical neurons treated with oxygen and glucose deprivation (OGD) with BP at 24[Formula: see text]h (40[Formula: see text]mg/kg) and 2[Formula: see text]h (10[Formula: see text][Formula: see text]mol/L), respectively, were used to determine the neuroprotective effects. The HIF-1[Formula: see text] accumulation, and S1P metabolism were assayed in the berberine-preconditioned neurons, and the HIF-1[Formula: see text]-mediated transcriptional modulation of sphingosine kinases (Sphk) 1 and 2 was analyzed using chromatin immunoprecipitation and real-time polymerase chain reaction. BP significantly prevented cerebral ischemic injury in the MCAO rats at 24[Formula: see text]h and 72[Formula: see text]h following ischemia/reperfusion. In OGD-treated neurons, BP enhanced HIF-1[Formula: see text] accumulation with activation of PI3K/Akt, and induced S1P production by activating Sphk2 via the promotion of HIF-1[Formula: see text]-mediated Sphk2 transcription. In conclusion, BP activated endogenous neuroprotective mechanisms associated with the S1P/HIF-1 pathway and helped protect neuronal cells against hypoxia/ischemia.

  9. Berberine Preconditioning Protects Neurons Against Ischemia via Sphingosine-1-Phosphate and Hypoxia-Inducible Factor-1[Formula: see text].

    PubMed

    Zhang, Qichun; Bian, Huimin; Guo, Liwei; Zhu, Huaxu

    2016-01-01

    Berberine exerts neuroprotective and modulates hypoxia inducible factor-1-alpha (HIF-1[Formula: see text]. Based on the role of HIF-1[Formula: see text] in hypoxia preconditioning and association between HIF-1[Formula: see text] and sphingosine-1-phosphate (S1P), we hypothesized that berberine preconditioning (BP) would ameliorate the cerebral injury induced by ischemia through activating the system of HIF-1[Formula: see text] and S1P. Adult male rats with middle cerebral artery occlusion (MCAO) and rat primary cortical neurons treated with oxygen and glucose deprivation (OGD) with BP at 24[Formula: see text]h (40[Formula: see text]mg/kg) and 2[Formula: see text]h (10[Formula: see text][Formula: see text]mol/L), respectively, were used to determine the neuroprotective effects. The HIF-1[Formula: see text] accumulation, and S1P metabolism were assayed in the berberine-preconditioned neurons, and the HIF-1[Formula: see text]-mediated transcriptional modulation of sphingosine kinases (Sphk) 1 and 2 was analyzed using chromatin immunoprecipitation and real-time polymerase chain reaction. BP significantly prevented cerebral ischemic injury in the MCAO rats at 24[Formula: see text]h and 72[Formula: see text]h following ischemia/reperfusion. In OGD-treated neurons, BP enhanced HIF-1[Formula: see text] accumulation with activation of PI3K/Akt, and induced S1P production by activating Sphk2 via the promotion of HIF-1[Formula: see text]-mediated Sphk2 transcription. In conclusion, BP activated endogenous neuroprotective mechanisms associated with the S1P/HIF-1 pathway and helped protect neuronal cells against hypoxia/ischemia. PMID:27430910

  10. Lysophospholipid receptor nomenclature review: IUPHAR Review 8

    PubMed Central

    Kihara, Yasuyuki; Maceyka, Michael; Spiegel, Sarah; Chun, Jerold

    2014-01-01

    Lysophospholipids encompass a diverse range of small, membrane-derived phospholipids that act as extracellular signals. The signalling properties are mediated by 7-transmembrane GPCRs, constituent members of which have continued to be identified after their initial discovery in the mid-1990s. Here we briefly review this class of receptors, with a particular emphasis on their protein and gene nomenclatures that reflect their cognate ligands. There are six lysophospholipid receptors that interact with lysophosphatidic acid (LPA): protein names LPA1 – LPA6 and italicized gene names LPAR1-LPAR6 (human) and Lpar1-Lpar6 (non-human). There are five sphingosine 1-phosphate (S1P) receptors: protein names S1P1-S1P5 and italicized gene names S1PR1-S1PR5 (human) and S1pr1-S1pr5 (non-human). Recent additions to the lysophospholipid receptor family have resulted in the proposed names for a lysophosphatidyl inositol (LPI) receptor – protein name LPI1 and gene name LPIR1 (human) and Lpir1 (non-human) – and three lysophosphatidyl serine receptors – protein names LyPS1, LyPS2, LyPS3 and gene names LYPSR1-LYPSR3 (human) and Lypsr1-Lypsr3 (non-human) along with a variant form that does not appear to exist in humans that is provisionally named LyPS2L. This nomenclature incorporates previous recommendations from the International Union of Basic and Clinical Pharmacology, the Human Genome Organization, the Gene Nomenclature Committee, and the Mouse Genome Informatix. PMID:24602016

  11. Synergy between Sphingosine 1-Phosphate and Lipopolysaccharide Signaling Promotes an Inflammatory, Angiogenic and Osteogenic Response in Human Aortic Valve Interstitial Cells

    PubMed Central

    Onecha, Esther; Maeso, Patricia; Crespo, Mariano Sánchez; Román, José Alberto San; García-Rodríguez, Carmen

    2014-01-01

    Given that the bioactive lipid sphingosine 1-phosphate is involved in cardiovascular pathophysiology, and since lipid accumulation and inflammation are hallmarks of calcific aortic stenosis, the role of sphingosine 1-phosphate on the pro-inflammatory/pro-osteogenic pathways in human interstitial cells from aortic and pulmonary valves was investigated. Real-time PCR showed sphingosine 1-phosphate receptor expression in aortic valve interstitial cells. Exposure of cells to sphingosine 1-phosphate induced pro-inflammatory responses characterized by interleukin-6, interleukin-8, and cyclooxygenase-2 up-regulations, as observed by ELISA and Western blot. Strikingly, cell treatment with sphingosine 1-phosphate plus lipopolysaccharide resulted in the synergistic induction of cyclooxygenase-2, and intercellular adhesion molecule 1, as well as the secretion of prostaglandin E2, the soluble form of the intercellular adhesion molecule 1, and the pro-angiogenic factor vascular endothelial growth factor-A. Remarkably, the synergistic effect was significantly higher in aortic valve interstitial cells from stenotic than control valves, and was drastically lower in cells from pulmonary valves, which rarely undergo stenosis. siRNA and pharmacological analysis revealed the involvement of sphingosine 1-phosphate receptors 1/3 and Toll-like receptor-4, and downstream signaling through p38/MAPK, protein kinase C, and NF-κB. As regards pro-osteogenic pathways, sphingosine 1-phosphate induced calcium deposition and the expression of the calcification markers bone morphogenetic protein-2 and alkaline phosphatase, and enhanced the effect of lipopolysaccharide, an effect that was partially blocked by inhibition of sphingosine 1-phosphate receptors 3/2 signaling. In conclusion, the interplay between sphingosine 1-phosphate receptors and Toll-like receptor 4 signaling leads to a cooperative up-regulation of inflammatory, angiogenic, and osteogenic pathways in aortic valve interstitial cells

  12. Aldo-keto Reductase Family 1 Member B 10 Mediates Liver Cancer Cell Proliferation through Sphingosine-1-Phosphate

    PubMed Central

    Jin, Junfei; Liao, Weijia; Yao, Wenmin; Zhu, Rongping; Li, Yulan; He, Songqing

    2016-01-01

    AKR1B10 is involved in hepatocarcinogenesis via modulation of fatty acid and lipid synthesis. AKR1B10 inhibition results in apoptosis of tumor cells whose lipids, especially phospholipids, were decreased by over 50%, suggesting involvement of phospholipids like sphingosine-1-phosphate (S1P) in AKR1B10’s oncogenic function. Using a co-culture system, we found that co-culture of QSG-7701 (human hepatocyte) with HepG2 (hepatoma cell line) increases QSG-7701’s proliferation, in which AKR1B10-S1P signaling plays a pivotal role. Consistent with previous findings, AKR1B10 mRNA and protein levels were higher in primary hepatocellular carcinoma (PHC) tissues than in peri-tumor tissues. Interestingly, the level of S1P was also higher in PHC tissues than in peri-tumor tissues. After analyzing the correlation between AKR1B10 mRNA expression in PHC tissues and the clinical data, we found that AKR1B10 mRNA expression was associated with serum alpha-fetoprotein (AFP), tumor-node-metastasis (TNM) stage, and lymph node metastasis, but not with other clinicopathologic variables. A higher AKR1B10 mRNA expression level is related to a shorter DFS (disease free survival) and OS (overall survival), serving as an independent predictor of DFS and OS in PHC patients with surgical resection. PMID:26948042

  13. Synthesis of phosphonate and phostone analogues of ribose-1-phosphates

    PubMed Central

    Nasomjai, Pitak; Slawin, Alexandra M Z

    2009-01-01

    Summary The synthesis of phosphonate analogues of ribose-1-phosphate and 5-fluoro-5-deoxyribose-1-phosphate is described. Preparations of both the α- and β-phosphonate anomers are reported for the ribose and 5-fluoro-5-deoxyribose series and a synthesis of the corresponding cyclic phostones of each α-ribose is also reported. These compounds have been prepared as tools to probe the details of fluorometabolism in S. cattleya. PMID:19777136

  14. Suppressive Effects of the Site 1 Protease (S1P) Inhibitor, PF-429242, on Dengue Virus Propagation.

    PubMed

    Uchida, Leo; Urata, Shuzo; Ulanday, Gianne Eduard L; Takamatsu, Yuki; Yasuda, Jiro; Morita, Kouichi; Hayasaka, Daisuke

    2016-02-01

    Dengue virus (DENV) infection causes one of the most widespread mosquito-borne diseases in the world. Despite the great need, effective vaccines and practical antiviral therapies are still under development. Intracellular lipid levels are regulated by sterol regulatory elements-binding proteins (SREBPs), which are activated by serine protease, site 1 protease (S1P). Small compound PF-429242 is known as a S1P inhibitor and the antivirus effects have been reported in some viruses. In this study, we examined the anti-DENV effects of PF-429242 using all four serotypes of DENV by several primate-derived cell lines. Moreover, emergence of drug-resistant DENV mutants was assessed by sequential passages with the drug. DENV dependency on intracellular lipids during their infection was also evaluated by adding extracellular lipids. The addition of PF-429242 showed suppression of viral propagation in all DENV serotypes. We showed that drug-resistant DENV mutants are unlikely to emerge after five times sequential passages through treatment with PF-429242. Although the levels of intracellular cholesterol and lipid droplets were reduced by PF-429242, viral propagations were not recovered by addition of exogenous cholesterol or fatty acids, indicating that the reduction of LD and cholesterol caused by PF-429242 treatment is not related to its mechanism of action against DENV propagation. Our results suggest that PF-429242 is a promising candidate for an anti-DENV agent. PMID:26875984

  15. Suppressive Effects of the Site 1 Protease (S1P) Inhibitor, PF-429242, on Dengue Virus Propagation

    PubMed Central

    Uchida, Leo; Urata, Shuzo; Ulanday, Gianne Eduard L.; Takamatsu, Yuki; Yasuda, Jiro; Morita, Kouichi; Hayasaka, Daisuke

    2016-01-01

    Dengue virus (DENV) infection causes one of the most widespread mosquito-borne diseases in the world. Despite the great need, effective vaccines and practical antiviral therapies are still under development. Intracellular lipid levels are regulated by sterol regulatory elements-binding proteins (SREBPs), which are activated by serine protease, site 1 protease (S1P). Small compound PF-429242 is known as a S1P inhibitor and the antivirus effects have been reported in some viruses. In this study, we examined the anti-DENV effects of PF-429242 using all four serotypes of DENV by several primate-derived cell lines. Moreover, emergence of drug-resistant DENV mutants was assessed by sequential passages with the drug. DENV dependency on intracellular lipids during their infection was also evaluated by adding extracellular lipids. The addition of PF-429242 showed suppression of viral propagation in all DENV serotypes. We showed that drug-resistant DENV mutants are unlikely to emerge after five times sequential passages through treatment with PF-429242. Although the levels of intracellular cholesterol and lipid droplets were reduced by PF-429242, viral propagations were not recovered by addition of exogenous cholesterol or fatty acids, indicating that the reduction of LD and cholesterol caused by PF-429242 treatment is not related to its mechanism of action against DENV propagation. Our results suggest that PF-429242 is a promising candidate for an anti-DENV agent. PMID:26875984

  16. Suppressive Effects of the Site 1 Protease (S1P) Inhibitor, PF-429242, on Dengue Virus Propagation.

    PubMed

    Uchida, Leo; Urata, Shuzo; Ulanday, Gianne Eduard L; Takamatsu, Yuki; Yasuda, Jiro; Morita, Kouichi; Hayasaka, Daisuke

    2016-02-10

    Dengue virus (DENV) infection causes one of the most widespread mosquito-borne diseases in the world. Despite the great need, effective vaccines and practical antiviral therapies are still under development. Intracellular lipid levels are regulated by sterol regulatory elements-binding proteins (SREBPs), which are activated by serine protease, site 1 protease (S1P). Small compound PF-429242 is known as a S1P inhibitor and the antivirus effects have been reported in some viruses. In this study, we examined the anti-DENV effects of PF-429242 using all four serotypes of DENV by several primate-derived cell lines. Moreover, emergence of drug-resistant DENV mutants was assessed by sequential passages with the drug. DENV dependency on intracellular lipids during their infection was also evaluated by adding extracellular lipids. The addition of PF-429242 showed suppression of viral propagation in all DENV serotypes. We showed that drug-resistant DENV mutants are unlikely to emerge after five times sequential passages through treatment with PF-429242. Although the levels of intracellular cholesterol and lipid droplets were reduced by PF-429242, viral propagations were not recovered by addition of exogenous cholesterol or fatty acids, indicating that the reduction of LD and cholesterol caused by PF-429242 treatment is not related to its mechanism of action against DENV propagation. Our results suggest that PF-429242 is a promising candidate for an anti-DENV agent.

  17. Soluble forms of VEGF receptor-1 and -2 promote vascular maturation via mural cell recruitment.

    PubMed

    Lorquet, Sophie; Berndt, Sarah; Blacher, Silvia; Gengoux, Emily; Peulen, Olivier; Maquoi, Erik; Noël, Agnès; Foidart, Jean-Michel; Munaut, Carine; Péqueux, Christel

    2010-10-01

    Two soluble forms of vascular endothelial growth factor (VEGF) receptors, sVEGFR-1 and sVEGFR-2, are physiologically released and overproduced in some pathologies. They are known to act as anti-VEGF agents. Here we report that these soluble receptors contribute to vessel maturation by mediating a dialogue between endothelial cells (ECs) and mural cells that leads to blood vessel stabilization. Through a multidisciplinary approach, we provide evidence that these soluble VEGF receptors promote mural cell migration through a paracrine mechanism involving interplay in ECs between VEGF/VEGFR-2 and sphingosine-1-phosphate type-1 (S1P)/S1P1 pathways that leads to endothelial nitric oxyde synthase (eNOS) activation. This new paradigm is supported by the finding that sVEGFR-1 and -2 perform the following actions: 1) induce an eNOS-dependent outgrowth of a mural cell network in an ex vivo model of angiogenesis, 2) increase the mural cell coverage of neovessels in vitro and in vivo, 3) promote mural cell migration toward ECs, and 4) stimulate endothelial S1P1 overproduction and eNOS activation that promote the migration and the recruitment of neighboring mural cells. These findings provide new insights into mechanisms regulating physiological and pathological angiogenesis and vessel stabilization.

  18. The Sphingolipid Receptor S1PR2 Is a Receptor for Nogo-A Repressing Synaptic Plasticity

    PubMed Central

    Arzt, Michael E.; Weinmann, Oliver; Obermair, Franz J.; Pernet, Vincent; Zagrebelsky, Marta; Delekate, Andrea; Iobbi, Cristina; Zemmar, Ajmal; Ristic, Zorica; Gullo, Miriam; Spies, Peter; Dodd, Dana; Gygax, Daniel; Korte, Martin; Schwab, Martin E.

    2014-01-01

    Nogo-A is a membrane protein of the central nervous system (CNS) restricting neurite growth and synaptic plasticity via two extracellular domains: Nogo-66 and Nogo-A-Δ20. Receptors transducing Nogo-A-Δ20 signaling remained elusive so far. Here we identify the G protein-coupled receptor (GPCR) sphingosine 1-phosphate receptor 2 (S1PR2) as a Nogo-A-Δ20-specific receptor. Nogo-A-Δ20 binds S1PR2 on sites distinct from the pocket of the sphingolipid sphingosine 1-phosphate (S1P) and signals via the G protein G13, the Rho GEF LARG, and RhoA. Deleting or blocking S1PR2 counteracts Nogo-A-Δ20- and myelin-mediated inhibition of neurite outgrowth and cell spreading. Blockade of S1PR2 strongly enhances long-term potentiation (LTP) in the hippocampus of wild-type but not Nogo-A−/− mice, indicating a repressor function of the Nogo-A/S1PR2 axis in synaptic plasticity. A similar increase in LTP was also observed in the motor cortex after S1PR2 blockade. We propose a novel signaling model in which a GPCR functions as a receptor for two structurally unrelated ligands, a membrane protein and a sphingolipid. Elucidating Nogo-A/S1PR2 signaling platforms will provide new insights into regulation of synaptic plasticity. PMID:24453941

  19. Modulation of Intrathymic Sphingosine-1-Phosphate Levels Promotes Escape of Immature Thymocytes to the Periphery with a Potential Proinflammatory Role in Chagas Disease

    PubMed Central

    Flávia Nardy, Ana; Santos, Leonardo; Freire-de-Lima, Célio Geraldo; Morrot, Alexandre

    2015-01-01

    The sphingosine-1-phosphate (S1P) system regulates both thymic and lymph nodes T cell egress which is essential for producing and maintaining the recycling T cell repertoire. Infection with the protozoan parasite Trypanosoma cruzi induces a hormonal systemic deregulation that has impact in the thymic S1P homeostasis that ultimately promotes the premature exit of immature CD4−CD8− T cells expressing TCR and proinflamatory cytokines to peripheral lymphoid organs, where they may interfere with adaptive immune responses. In what follows, we review recent findings revealing escape of these immature T cells exhibiting an activation profile to peripheral compartments of the immune system in both experimental murine and human models of Chagas disease. PMID:26347020

  20. Expression of LPP3 in Bergmann glia is required for proper cerebellar sphingosine-1-phosphate metabolism/signaling and development

    PubMed Central

    López-Juárez, Alejandro; Morales-Lázaro, Sara; Sánchez-Sánchez, Roberto; Sunkara, Manjula; Lomelí, Hilda; Velasco, Iván; Morris, Andrew J.; Escalante-Alcalde, Diana

    2011-01-01

    Bioactive lipids serve as intracellular and extracellular mediators in cell signaling in normal and pathological conditions. Here we describe that an important regulator of some of these lipids, the lipid phosphate phosphatase-3 (LPP3), is abundantly expressed in specific plasma membrane domains of Bergmann glia (BG), a specialized type of astrocyte with key roles in cerebellum development and physiology. Mice selectively lacking expression of LPP3/Ppap2b in the nervous system are viable and fertile but exhibit defects in postnatal cerebellum development and modifications in the cytoarchitecture and arrangement of BG with a mild non-progressive motor coordination defect. Lipid and gene profiling studies in combination with pharmacological treatments suggest that most of these effects are associated with alterations in sphingosine-1-phosphate (S1P) metabolism and signaling. Altogether our data indicate that LPP3 participates in several aspects of neuron-glia communication required for proper cerebellum development. PMID:21319224

  1. Expression of LPP3 in Bergmann glia is required for proper cerebellar sphingosine-1-phosphate metabolism/signaling and development.

    PubMed

    López-Juárez, Alejandro; Morales-Lázaro, Sara; Sánchez-Sánchez, Roberto; Sunkara, Manjula; Lomelí, Hilda; Velasco, Iván; Morris, Andrew J; Escalante-Alcalde, Diana

    2011-04-01

    Bioactive lipids serve as intracellular and extracellular mediators in cell signaling in normal and pathological conditions. Here we describe that an important regulator of some of these lipids, the lipid phosphate phosphatase-3 (LPP3), is abundantly expressed in specific plasma membrane domains of Bergmann glia (BG), a specialized type of astrocyte with key roles in cerebellum development and physiology. Mice selectively lacking expression of LPP3/Ppap2b in the nervous system are viable and fertile but exhibit defects in postnatal cerebellum development and modifications in the cytoarchitecture and arrangement of BG with a mild non-progressive motor coordination defect. Lipid and gene profiling studies in combination with pharmacological treatments suggest that most of these effects are associated with alterations in sphingosine-1-phosphate (S1P) metabolism and signaling. Altogether our data indicate that LPP3 participates in several aspects of neuron-glia communication required for proper cerebellum development.

  2. Myocardin-Related Transcription Factor A and Yes-Associated Protein Exert Dual Control in G Protein-Coupled Receptor- and RhoA-Mediated Transcriptional Regulation and Cell Proliferation

    PubMed Central

    Yu, Olivia M.; Miyamoto, Shigeki

    2015-01-01

    The ability of a subset of G protein-coupled receptors (GPCRs) to activate RhoA endows them with unique growth-regulatory properties. Two transcriptional pathways are activated through GPCRs and RhoA, one utilizing the transcriptional coactivator myocardin-related transcription factor A (MRTF-A) and serum response factor (SRF) and the other using the transcriptional coactivator Yes-associated protein (YAP) and TEA domain family members (TEAD). These pathways have not been compared for their relative levels of importance and potential interactions in RhoA target gene expression. GPCRs for thrombin and sphingosine-1-phosphate (S1P) on human glioblastoma cells robustly couple to RhoA and induce the matricelluar protein CCN1. Knockdown of either MRTF-A or YAP abrogates S1P-stimulated CCN1 expression, demonstrating that both coactivators are required. MRTF-A and YAP are also both required for transcriptional control of other S1P-regulated genes in various cell types and for S1P-stimulated glioblastoma cell proliferation. Interactions between MRTF-A and YAP are suggested by their synergistic effects on SRE.L- and TEAD-luciferase expression. Moreover, MRTF-A and YAP associate in coimmunoprecipitations from S1P-stimulated cells. Chromatin immunoprecipitation (ChIP) analysis of the CCN1 gene promoter demonstrated that S1P increases coactivator binding at the canonical transcription factor sequences. Unexpectedly, S1P also enhances MRTF-A binding at TEA sites. Our findings reveal that GPCR- and RhoA-regulated gene expression requires dual input and integration of two distinct transcriptional pathways. PMID:26459764

  3. Myocardin-Related Transcription Factor A and Yes-Associated Protein Exert Dual Control in G Protein-Coupled Receptor- and RhoA-Mediated Transcriptional Regulation and Cell Proliferation.

    PubMed

    Yu, Olivia M; Miyamoto, Shigeki; Brown, Joan Heller

    2016-01-01

    The ability of a subset of G protein-coupled receptors (GPCRs) to activate RhoA endows them with unique growth-regulatory properties. Two transcriptional pathways are activated through GPCRs and RhoA, one utilizing the transcriptional coactivator myocardin-related transcription factor A (MRTF-A) and serum response factor (SRF) and the other using the transcriptional coactivator Yes-associated protein (YAP) and TEA domain family members (TEAD). These pathways have not been compared for their relative levels of importance and potential interactions in RhoA target gene expression. GPCRs for thrombin and sphingosine-1-phosphate (S1P) on human glioblastoma cells robustly couple to RhoA and induce the matricelluar protein CCN1. Knockdown of either MRTF-A or YAP abrogates S1P-stimulated CCN1 expression, demonstrating that both coactivators are required. MRTF-A and YAP are also both required for transcriptional control of other S1P-regulated genes in various cell types and for S1P-stimulated glioblastoma cell proliferation. Interactions between MRTF-A and YAP are suggested by their synergistic effects on SRE.L- and TEAD-luciferase expression. Moreover, MRTF-A and YAP associate in coimmunoprecipitations from S1P-stimulated cells. Chromatin immunoprecipitation (ChIP) analysis of the CCN1 gene promoter demonstrated that S1P increases coactivator binding at the canonical transcription factor sequences. Unexpectedly, S1P also enhances MRTF-A binding at TEA sites. Our findings reveal that GPCR- and RhoA-regulated gene expression requires dual input and integration of two distinct transcriptional pathways.

  4. Hit-to-lead evaluation of a novel class of sphingosine 1-phosphate lyase inhibitors.

    PubMed

    Dinges, Jurgen; Harris, Christopher M; Wallace, Grier A; Argiriadi, Maria A; Queeney, Kara L; Perron, Denise C; Dominguez, Eric; Kebede, Tegest; Desino, Kelly E; Patel, Hetal; Vasudevan, Anil

    2016-05-01

    Inhibition of sphingosine-1-phosphate lyase has recently been proposed as a potential treatment option for inflammatory disorders such as multiple sclerosis, rheumatoid arthritis, and inflammatory bowel disease. In this report we describe our hit-to-lead evaluation of the isoxazolecarboxamide 6, a high-throughput screening hit (in vitro IC50=1.0 μM, cell IC50=1.8 μM), as a novel S1P lyase inhibitor. We were able to establish basic structure-activity relationships around 6 and succeeded in obtaining X-ray structural information which enabled structure-based design. With the discovery of 28, enzyme activity was quickly improved to IC50=120 nM and cell potency to IC50=230 nM. The main liability in the established isoxazolecarboxamide hit series was determined to be metabolic stability. In particular we identified that future lead-optimization efforts to overcome this problem should focus on blocking the N-dealkylation on the secondary amine. PMID:27020302

  5. Proximal tubule sphingosine kinase-1 has a critical role in A1 adenosine receptor-mediated renal protection from ischemia

    PubMed Central

    Park, Sang Won; Kim, Mihwa; Kim, Joo Yun; Brown, Kevin M.; Haase, Volker H.; D’Agati, Vivette D.; Lee, H. Thomas

    2012-01-01

    Renal ischemia reperfusion injury is a major cause of acute kidney injury. We previously found that renal A1 adenosine receptor (A1AR) activation attenuated multiple cell death pathways including necrosis, apoptosis and inflammation. Here, we tested whether induction of cytoprotective sphingosine kinase (SK)-1 and sphingosine-1 phosphate (S1P) synthesis might be the mechanism of protection. A selective A1AR agonist (CCPA) increased the synthesis of S1P and selectively induced SK-1 in mouse kidney and HK-2 cells. This agonist failed to protect SK1-knockout but protected SK2-knockout mice against renal ischemia reperfusion injury indicating a critical role of SK1 in A1AR-mediated renal protection. Inhibition of SK prevented A1AR-mediated defense against necrosis and apoptosis in HK-2 cells. A selective S1P1R antagonist (W146) and global in vivo gene knockdown of S1P1Rs with small interfering RNA completely abolished the renal protection provided by CCPA. Mice selectively deficient in renal proximal tubule S1P1Rs (S1P1Rflox/flox PEPCKCre/−) were not protected against renal ischemia reperfusion injury by CCPA. Mechanistically, CCPA increased nuclear translocation of hypoxia inducible factor-1α in HK-2 cells and selective hypoxia inducible factor-1α inhibition blocked A1AR-mediated induction of SK1. Thus, proximal tubule SK-1 has a critical role in A1AR-mediated protection against renal ischemia reperfusion injury. PMID:22695326

  6. Test and evaluation of the chloride Spegel S1P108/30 electric vehicle battery charger

    NASA Astrophysics Data System (ADS)

    Driggans, R. L.; Keller, A. S.

    1985-09-01

    The Chloride Spegel Model S1P108/30 electric vehicle battery charger was tested by the Tennessee Valley Authority (TVA) as an account of work sponsored by the Electric Power Research Institute (EPRI). Charger input/output voltage, current, and power characteristics and input waveform distortion were measured; and induced electromagnetic interference was evaluated as the charger recharged a lead-acid battery pack. Electrical quantities were measured with precision volt-ampere-watt meters, frequency counters, a digital-storage oscilloscope, and a spectrum analyzer. THe Chloride charger required 8.5 hours to recharge a 216V tubular plate lead-acid battery from 100 percent depth of discharge (DOD). Energy efficiency was 83 percent, specific power was 37.4 W/kg (17.0 W/lb), input current distortion varied from 22.4 to 34.1 percent, and electromagnetic interference was observed on AM radio. Tests were conducted with the battery at initial DOD of 100, 75, 50, and 25 percent. Charge factor was 1.14 from 100-percent DOD, increasing to 1.39 from 25-percent DOD.

  7. (7-Benzyloxy-2,3-dihydro-1H-pyrrolo[1,2-a]indol-1-yl)acetic Acids as S1P1 Functional Antagonists

    PubMed Central

    2014-01-01

    S1P1 is a validated target for treatment of autoimmune disease, and functional antagonists with superior safety and pharmacokinetic properties are being sought as second generation therapeutics. We describe the discovery and optimization of (7-benzyloxy-2,3-dihydro-1H-pyrrolo[1,2-a]indol-1-yl)acetic acids as potent, centrally available, direct acting S1P1 functional antagonists, with favorable pharmacokinetic and safety properties. PMID:25516794

  8. Sphingosine kinase 1 is upregulated with lysophosphatidic acid receptor 2 in human colorectal cancer

    PubMed Central

    Shida, Dai; Inoue, Satoru; Yoshida, Yuki; Kodaka, Atsushi; Tsuji, Tsutomu; Tsuiji, Makoto

    2016-01-01

    AIM: To examine the expression of SphK1, an oncogenic kinase that produces sphingosine 1-phosphate (S1P), and its correlation with the expression of LPAR2, a major lysophosphatidic acid (LPA) receptor overexpressed in various cancers, in human colorectal cancer. METHODS: Real-time reverse-transcription polymerase chain reaction was used to measure the mRNA expression of SphK1, LPAR2, and the three major S1P receptors in 27 colorectal cancer samples and corresponding normal tissue samples. We also examined the correlation between the expression of SphK1 and LPAR2. RESULTS: Colorectal cancer tissue in 22 of 27 patients had higher levels of SphK1 mRNA than in normal tissue. In two-thirds of the samples, SphK1 mRNA expression was more than two-fold higher than in normal tissue. Consistent with previous reports, LPAR2 mRNA expression in 20 of 27 colorectal cancer tissue samples was higher compared to normal tissue samples. Expression profiles of all three major S1P receptors, S1PR1, S1PR2, and S1PR3, varied without any trend, with no significant difference in expression between cancer and normal tissues. A highly significant positive correlation was found between SphK1 and LPAR2 expression [Pearson’s correlation coefficient (r) = 0.784 and P < 0.01]. The mRNA levels of SphK1 and LPAR2 did not correlate with TNM stage. CONCLUSION: Our findings suggest that S1P and LPA may play important roles in the development of colorectal cancer via the upregulation of SphK1 and LPAR2, both of which could serve as new therapeutic targets in the treatment of colorectal cancer. PMID:26937138

  9. Three Phases of CD8 T Cell Response in the Lung Following H1N1 Influenza Infection and Sphingosine 1 Phosphate Agonist Therapy

    PubMed Central

    Matheu, Melanie P.; Teijaro, John R.; Walsh, Kevin B.; Greenberg, Milton L.; Marsolais, David; Parker, Ian; Rosen, Hugh; Oldstone, Michael B A.; Cahalan, Michael D.

    2013-01-01

    Influenza-induced lung edema and inflammation are exacerbated by a positive feedback loop of cytokine and chemokine production termed a ‘cytokine storm’, a hallmark of increased influenza-related morbidity and mortality. Upon infection, an immune response is rapidly initiated in the lungs and draining lymph node, leading to expansion of virus-specific effector cells. Using two-photon microscopy, we imaged the dynamics of dendritic cells (DC) and virus-specific eGFP+CD8+ T cells in the lungs and draining mediastinal lymph nodes during the first two weeks following influenza infection. Three distinct phases of T cell and CD11c+ DC behavior were revealed: 1) Priming, facilitated by the arrival of lung DCs in the lymph node and characterized by antigen recognition and expansion of antigen-specific CD8+ T cells; asymmetric T cell division in contact with DCs was frequently observed. 2) Clearance, during which DCs re-populate the lung and T cells leave the draining lymph node and re-enter the lung tissue where enlarged, motile T cells come into contact with DCs and form long-lived interactions. 3) Maintenance, characterized by T-cell scanning of the lung tissue and dissociation from local antigen presenting cells; the T cells spend less time in association with DCs and migrate rapidly on collagen. A single dose of a sphingosine-1-phosphate receptor agonist, AAL-R, sufficient to suppress influenza-induced cytokine-storm, altered T cell and DC behavior during influenza clearance, delaying T cell division, cellular infiltration in the lung, and suppressing T-DC interactions in the lung. Our results provide a detailed description of T cell and DC choreography and dynamics in the lymph node and the lung during influenza infection. In addition, we suggest that phase lags in T cell and DC dynamics induced by targeting S1P receptors in vivo may attenuate the intensity of the immune response and can be manipulated for therapeutic benefit. PMID:23533579

  10. Individual variation of human S1P₁ coding sequence leads to heterogeneity in receptor function and drug interactions.

    PubMed

    Obinata, Hideru; Gutkind, Sarah; Stitham, Jeremiah; Okuno, Toshiaki; Yokomizo, Takehiko; Hwa, John; Hla, Timothy

    2014-12-01

    Sphingosine 1-phosphate receptor 1 (S1P₁), an abundantly-expressed G protein-coupled receptor which regulates key vascular and immune responses, is a therapeutic target in autoimmune diseases. Fingolimod/Gilenya (FTY720), an oral medication for relapsing-remitting multiple sclerosis, targets S1P₁ receptors on immune and neural cells to suppress neuroinflammation. However, suppression of endothelial S1P₁ receptors is associated with cardiac and vascular adverse effects. Here we report the genetic variations of the S1P₁ coding region from exon sequencing of >12,000 individuals and their functional consequences. We conducted functional analyses of 14 nonsynonymous single nucleotide polymorphisms (SNPs) of the S1PR1 gene. One SNP mutant (Arg¹²⁰ to Pro) failed to transmit sphingosine 1-phosphate (S1P)-induced intracellular signals such as calcium increase and activation of p44/42 MAPK and Akt. Two other mutants (Ile⁴⁵ to Thr and Gly³⁰⁵ to Cys) showed normal intracellular signals but impaired S1P-induced endocytosis, which made the receptor resistant to FTY720-induced degradation. Another SNP mutant (Arg¹³ to Gly) demonstrated protection from coronary artery disease in a high cardiovascular risk population. Individuals with this mutation showed a significantly lower percentage of multi-vessel coronary obstruction in a risk factor-matched case-control study. This study suggests that individual genetic variations of S1P₁ can influence receptor function and, therefore, infer differential disease risks and interaction with S1P₁-targeted therapeutics. PMID:25293589

  11. Human subtilase SKI-1/S1P is a master regulator of the HCV Lifecycle and a potential host cell target for developing indirect-acting antiviral agents.

    PubMed

    Olmstead, Andrea D; Knecht, Wolfgang; Lazarov, Ina; Dixit, Surjit B; Jean, François

    2012-01-01

    HCV infection is a major risk factor for liver cancer and liver transplantation worldwide. Overstimulation of host lipid metabolism in the liver by HCV-encoded proteins during viral infection creates a favorable environment for virus propagation and pathogenesis. In this study, we hypothesize that targeting cellular enzymes acting as master regulators of lipid homeostasis could represent a powerful approach to developing a novel class of broad-spectrum antivirals against infection associated with human Flaviviridae viruses such as hepatitis C virus (HCV), whose assembly and pathogenesis depend on interaction with lipid droplets (LDs). One such master regulator of cholesterol metabolic pathways is the host subtilisin/kexin-isozyme-1 (SKI-1)--or site-1 protease (S1P). SKI-1/S1P plays a critical role in the proteolytic activation of sterol regulatory element binding proteins (SREBPs), which control expression of the key enzymes of cholesterol and fatty-acid biosynthesis. Here we report the development of a SKI-1/S1P-specific protein-based inhibitor and its application to blocking the SREBP signaling cascade. We demonstrate that SKI-1/S1P inhibition effectively blocks HCV from establishing infection in hepatoma cells. The inhibitory mechanism is associated with a dramatic reduction in the abundance of neutral lipids, LDs, and the LD marker: adipose differentiation-related protein (ADRP)/perilipin 2. Reduction of LD formation inhibits virus assembly from infected cells. Importantly, we confirm that SKI-1/S1P is a key host factor for HCV infection by using a specific active, site-directed, small-molecule inhibitor of SKI-1/S1P: PF-429242. Our studies identify SKI-1/S1P as both a novel regulator of the HCV lifecycle and as a potential host-directed therapeutic target against HCV infection and liver steatosis. With identification of an increasing number of human viruses that use host LDs for infection, our results suggest that SKI-1/S1P inhibitors may allow development of

  12. Controlled release of sphingosine-1-phosphate agonist with gelatin hydrogels for macrophage recruitment.

    PubMed

    Murakami, Masahiro; Saito, Takashi; Tabata, Yasuhiko

    2014-11-01

    The objective of this study is to design a drug delivery system (DDS) for the in vivo promotion of macrophage recruitment. As the drug, a water-insoluble agonist of sphingosine-1-phosphate type 1 receptor (SEW2871) was selected. SEW2871 (SEW) was water-solubilized by micelle formation with gelatin grafted by L-lactic acid oligomer. SEW micelles were mixed with gelatin, followed by dehydrothermal crosslinking of gelatin to obtain gelatin hydrogels incorporating SEW micelles. SEW was released from the hydrogels incorporating SEW micelles in vitro and in vivo. The water-solubilized SEW showed in vitro macrophage migration activity. When implanted into the back subcutis or the skin wound defect of mice, the hydrogel incorporating SEW micelles promoted macrophage migration toward the tissue around the implanted site to a significantly great extent compared with SEW-free hydrogel and that mixed with SEW micelles. The hydrogel is a promising DDS to enhance macrophage recruitment in vivo. PMID:25038462

  13. Ceramide 1-phosphate stimulates glucose uptake in macrophages

    PubMed Central

    Ouro, Alberto; Arana, Lide; Gangoiti, Patricia; Rivera, Io-Guané; Ordoñez, Marta; Trueba, Miguel; Lankalapalli, Ravi S.; Bittman, Robert; Gomez-Muñoz, Antonio

    2014-01-01

    It is well established that ceramide 1-phosphate (C1P) is mitogenic and antiapoptotic, and that it is implicated in the regulation of macrophage migration. These activities require high energy levels to be available in cells. Macrophages obtain most of their energy from glucose. In this work, we demonstrate that C1P enhances glucose uptake in RAW264.7 macrophages. The major glucose transporter involved in this action was found to be GLUT 3, as determined by measuring its translocation from the cytosol to the plasma membrane. C1P-stimulated glucose uptake was blocked by selective inhibitors of phosphatidylinositol 3-kinase (PI3K) or Akt, also known as protein kinase B (PKB), and by specific siRNAs to silence the genes encoding for these kinases. C1P-stimulated glucose uptake was also inhibited by pertussis toxin (PTX) and by the siRNA that inhibited GLUT 3 expression. C1P increased the affinity of the glucose transporter for its substrate, and enhanced glucose metabolism to produce ATP. The latter action was also inhibited by PI3K- and Akt-selective inhibitors, PTX, or by specific siRNAs to inhibit GLUT 3 expression. PMID:23333242

  14. G protein-coupled receptor kinase 2 positively regulates epithelial cell migration

    PubMed Central

    Penela, Petronila; Ribas, Catalina; Aymerich, Ivette; Eijkelkamp, Niels; Barreiro, Olga; Heijnen, Cobi J; Kavelaars, Annemieke; Sánchez-Madrid, Francisco; Mayor, Federico

    2008-01-01

    Cell migration requires integration of signals arising from both the extracellular matrix and messengers acting through G protein-coupled receptors (GPCRs). We find that increased levels of G protein-coupled receptor kinase 2 (GRK2), a key player in GPCR regulation, potentiate migration of epithelial cells towards fibronectin, whereas such process is decreased in embryonic fibroblasts from hemizygous GRK2 mice or upon knockdown of GRK2 expression. Interestingly, the GRK2 effect on fibronectin-mediated cell migration involves the paracrine/autocrine activation of a sphingosine-1-phosphate (S1P) Gi-coupled GPCR. GRK2 positively modulates the activity of the Rac/PAK/MEK/ERK pathway in response to adhesion and S1P by a mechanism involving the phosphorylation-dependent, dynamic interaction of GRK2 with GIT1, a key scaffolding protein in cell migration processes. Furthermore, decreased GRK2 levels in hemizygous mice result in delayed wound healing rate in vivo, consistent with a physiological role of GRK2 as a regulator of coordinated integrin and GPCR-directed epithelial cell migration. PMID:18369319

  15. 21 CFR 862.1315 - Galactose-1-phosphate uridyl transferase test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1315 Galactose-1-phosphate uridyl transferase test system. (a)...

  16. 21 CFR 862.1315 - Galactose-1-phosphate uridyl transferase test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1315 Galactose-1-phosphate uridyl transferase test system. (a)...

  17. 21 CFR 862.1315 - Galactose-1-phosphate uridyl transferase test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1315 Galactose-1-phosphate uridyl transferase test system. (a)...

  18. Lipid G Protein-coupled Receptor Ligand Identification Using β-Arrestin PathHunter™ Assay

    PubMed Central

    Yin, Hong; Chu, Alan; Li, Wei; Wang, Bin; Shelton, Fabiola; Otero, Francella; Nguyen, Deborah G.; Caldwell, Jeremy S.; Chen, Yu Alice

    2009-01-01

    A growing number of orphan G-protein-coupled receptors (GPCRs) have been reported to be activated by lipid ligands, such as lysophosphatidic acid, sphingosine 1-phosphate (S1P), and cannabinoids, for which there are already well established receptors. These new ligand claims are controversial due to either lack of independent confirmations or conflicting reports. We used the β-arrestin PathHunter™ assay system, a newly developed, generic GPCR assay format that measures β-arrestin binding to GPCRs, to evaluate lipid receptor and ligand pairing. This assay eliminates interference from endogenous receptors on the parental cells because it measures a signal that is specifically generated by the tagged receptor and is immediately downstream of receptor activation. We screened a large number of newly “deorphaned” receptors (GPR23, GPR92, GPR55, G2A, GPR18, GPR3, GPR6, GPR12, and GPR63) and control receptors against a collection of ∼400 lipid molecules to try to identify the receptor ligand in an unbiased fashion. GPR92 was confirmed to be a lysophosphatidic acid receptor with weaker responses to farnesyl pyrophosphate and geranylgeranyl diphosphate. The putative cannabinoid receptor GPR55 responded strongly to AM251, rimonabant, and lysophosphatidylinositol but only very weakly to endocannabinoids. G2A receptor was confirmed to be an oxidized free fatty acid receptor. In addition, we discovered that 3,3′-diindolylmethane, a dietary molecule from cruciferous vegetables, which has known anti-cancer properties, to be a CB2 receptor partial agonist, with binding affinity around 1 μm. The anti-inflammatory effect of 3,3′-diindolylmethane in RAW264.7 cells was shown to be partially mediated by CB2. PMID:19286662

  19. Influence of calcium on ceramide-1-phosphate monolayers

    PubMed Central

    Brezesinski, Gerald; Hill, Alexandra; Gericke, Arne

    2016-01-01

    Summary Ceramide-1-phosphate (C1P) plays an important role in several biological processes, being identified as a key regulator of many protein functions. For instance, it acts as a mediator of inflammatory responses. The mediation of the inflammation process happens due to the interaction of C1P with the C2 domain of cPLA2α, an effector protein that needs the presence of submicromolar concentrations of calcium ions. The aim of this study was to determine the phase behaviour and structural properties of C1P in the presence and absence of millimolar quantities of calcium in a well-defined pH environment. For that purpose, we used monomolecular films of C1P at the soft air/liquid interface with calcium ions in the subphase. The pH was varied to change the protonation degree of the C1P head group. We used surface pressure versus molecular area isotherms coupled with other monolayer techniques as Brewster angle microscopy (BAM), infrared reflection–absorption spectroscopy (IRRAS) and grazing incidence X-ray diffraction (GIXD). The isotherms indicate that C1P monolayers are in a condensed state in the presence of calcium ions, regardless of the pH. At higher pH without calcium ions, the monolayer is in a liquid-expanded state due to repulsion between the negatively charged phosphate groups of the C1P molecules. When divalent calcium ions are added, they are able to bridge the highly charged phosphate groups, enhancing the regular arrangement of the head groups. Similar solidification of the monolayer structure can be seen in the presence of a 150 times larger concentration of monovalent sodium ions. Therefore, calcium ions have clearly a strong affinity for the phosphomonoester of C1P. PMID:26977381

  20. Enterobacteria-secreted particles induce production of exosome-like S1P-containing particles by intestinal epithelium to drive Th17-mediated tumorigenesis

    PubMed Central

    Deng, Zhongbin; Mu, Jingyao; Tseng, Michael; Wattenberg, Binks; Zhuang, Xiaoying; Egilmez, Nejat K; Wang, Qilong; Zhang, Lifeng; Norris, James; Guo, Haixun; Yan, Jun; Haribabu, Bodduluri; Miller, Donald; Zhang, Huang-Ge

    2015-01-01

    Gut-associated inflammation plays a crucial role in the progression of colon cancer. Here, we identify a novel pathogen-host interaction that promotes gut inflammation and the development of colon cancer. We find that enteropathogenic bacteria-secreted particles (ET-BSPs) stimulate intestinal epithelium to produce IDENs (intestinal mucosa-derived exosome-like nanoparticles) containing elevated levels of sphingosine-1-phosphate, CCL20 and prostaglandin E2 (PGE2). CCL20 and PGE2 are required for the recruitment and proliferation, respectively, of Th17 cells, and these processes also involve the MyD88-mediated pathway. By influencing the recruitment and proliferation of Th17 cells in the intestine, IDENs promote colon cancer. We demonstrate the biological effect of sphingosine-1-phosphate contained in IDENs on tumor growth in spontaneous and transplanted colon cancer mouse models. These findings provide deeper insights into how host-microbe relationships are mediated by particles secreted from both bacterial and host cells. PMID:25907800

  1. Enterobacteria-secreted particles induce production of exosome-like S1P-containing particles by intestinal epithelium to drive Th17-mediated tumorigenesis.

    PubMed

    Deng, Zhongbin; Mu, Jingyao; Tseng, Michael; Wattenberg, Binks; Zhuang, Xiaoying; Egilmez, Nejat K; Wang, Qilong; Zhang, Lifeng; Norris, James; Guo, Haixun; Yan, Jun; Haribabu, Bodduluri; Miller, Donald; Zhang, Huang-Ge

    2015-01-01

    Gut-associated inflammation plays a crucial role in the progression of colon cancer. Here, we identify a novel pathogen-host interaction that promotes gut inflammation and the development of colon cancer. We find that enteropathogenic bacteria-secreted particles (ET-BSPs) stimulate intestinal epithelium to produce IDENs (intestinal mucosa-derived exosome-like nanoparticles) containing elevated levels of sphingosine-1-phosphate, CCL20 and prostaglandin E2 (PGE2). CCL20 and PGE2 are required for the recruitment and proliferation, respectively, of Th17 cells, and these processes also involve the MyD88-mediated pathway. By influencing the recruitment and proliferation of Th17 cells in the intestine, IDENs promote colon cancer. We demonstrate the biological effect of sphingosine-1-phosphate contained in IDENs on tumour growth in spontaneous and transplanted colon cancer mouse models. These findings provide deeper insights into how host-microbe relationships are mediated by particles secreted from both bacterial and host cells. PMID:25907800

  2. Orally active 7-substituted (4-benzylphthalazin-1-yl)-2-methylpiperazin-1-yl]nicotinonitriles as active-site inhibitors of sphingosine 1-phosphate lyase for the treatment of multiple sclerosis.

    PubMed

    Weiler, Sven; Braendlin, Nadine; Beerli, Christian; Bergsdorf, Christian; Schubart, Anna; Srinivas, Honnappa; Oberhauser, Berndt; Billich, Andreas

    2014-06-26

    Sphingosine 1-phosphate (S1P) lyase has recently been implicated as a therapeutic target for the treatment of multiple sclerosis (MS), based on studies in a genetic mouse model. Potent active site directed inhibitors of the enzyme are not known so far. Here we describe the discovery of (4-benzylphthalazin-1-yl)-2-methylpiperazin-1-yl]nicotinonitrile 5 in a high-throughput screen using a biochemical assay, and its further optimization. This class of compounds was found to inhibit catalytic activity of S1PL by binding to the active site of the enzyme, as seen in the cocrystal structure of derivative 31 with the homodimeric human S1P lyase. 31 induces profound reduction of peripheral T cell numbers after oral dosage and confers pronounced protection in a rat model of multiple sclerosis. In conclusion, this novel class of direct S1P lyase inhibitors provides excellent tools to further explore the therapeutic potential of T cell-targeted therapies in multiple sclerosis and other autoimmune and inflammatory diseases.

  3. Sphingosine-1-phosphate and ceramide are associated with health and atresia of bovine ovarian antral follicles.

    PubMed

    Hernández-Coronado, C G; Guzmán, A; Espinosa-Cervantes, R; Romano, M C; Verde-Calvo, J R; Rosales-Torres, A M

    2015-02-01

    The follicle destiny towards ovulation or atresia is multi-factorial in nature and involves outcries, paracrine and endocrine factors that promote cell proliferation and survival (development) or unchain apoptosis as part of the atresia process. In several types of cells, sphingosine-1-phospate (S1P) promotes cellular proliferation and survival, whereas ceramide (CER) triggers cell death, and the S1P/CER ratio may determine the fate of the cell. The aim of present study was to quantify S1P and CER concentrations and their ratio in bovine antral follicles of 8 to 17 mm classified as healthy and atretic antral follicles. Follicles were dissected from cow ovaries collected from a local abattoir. The theca cell layer, the granulosa cells and follicular fluid were separated, and 17β-estradiol (E2) and progesterone (P4) concentrations were measured in the follicular fluid by radioimmunoassay. Based on the E2/P4 ratio, the follicles were classified as healthy (2.2±0.3) or atretic (0.2±0.3). In both follicular compartments (granulosa and theca cell layer), sphingolipids were extracted and S1P and CER concentrations were quantified by HPLC (XTerra RP18; 5 µm, 3.0×150 mm column). Results showed that in both follicular compartments, S1P concentrations were higher in healthy antral follicles than in atretic antral follicles (P<0.05). The concentration of CER in the granulosa cells was higher in atretic antral follicles than in healthy antral follicles, but no differences were observed in the theca cell layer. The S1P/CER ratio in both follicular compartments was also higher in healthy antral follicles. Interestingly, in these follicles, there was a 45-fold greater concentration of S1P than CER in the granulosa cells (P<0.05), whereas in the theca cell layer, S1P had only a 14-fold greater concentration than CER when compared with atretic antral follicles. These results suggest that S1P plays a role in follicle health, increasing cellular proliferation and survival. In

  4. Sphingosine-1-phosphate and ceramide are associated with health and atresia of bovine ovarian antral follicles.

    PubMed

    Hernández-Coronado, C G; Guzmán, A; Espinosa-Cervantes, R; Romano, M C; Verde-Calvo, J R; Rosales-Torres, A M

    2015-02-01

    The follicle destiny towards ovulation or atresia is multi-factorial in nature and involves outcries, paracrine and endocrine factors that promote cell proliferation and survival (development) or unchain apoptosis as part of the atresia process. In several types of cells, sphingosine-1-phospate (S1P) promotes cellular proliferation and survival, whereas ceramide (CER) triggers cell death, and the S1P/CER ratio may determine the fate of the cell. The aim of present study was to quantify S1P and CER concentrations and their ratio in bovine antral follicles of 8 to 17 mm classified as healthy and atretic antral follicles. Follicles were dissected from cow ovaries collected from a local abattoir. The theca cell layer, the granulosa cells and follicular fluid were separated, and 17β-estradiol (E2) and progesterone (P4) concentrations were measured in the follicular fluid by radioimmunoassay. Based on the E2/P4 ratio, the follicles were classified as healthy (2.2±0.3) or atretic (0.2±0.3). In both follicular compartments (granulosa and theca cell layer), sphingolipids were extracted and S1P and CER concentrations were quantified by HPLC (XTerra RP18; 5 µm, 3.0×150 mm column). Results showed that in both follicular compartments, S1P concentrations were higher in healthy antral follicles than in atretic antral follicles (P<0.05). The concentration of CER in the granulosa cells was higher in atretic antral follicles than in healthy antral follicles, but no differences were observed in the theca cell layer. The S1P/CER ratio in both follicular compartments was also higher in healthy antral follicles. Interestingly, in these follicles, there was a 45-fold greater concentration of S1P than CER in the granulosa cells (P<0.05), whereas in the theca cell layer, S1P had only a 14-fold greater concentration than CER when compared with atretic antral follicles. These results suggest that S1P plays a role in follicle health, increasing cellular proliferation and survival. In

  5. Implication of matrix metalloproteinases 2 and 9 in ceramide 1-phosphate-stimulated macrophage migration.

    PubMed

    Ordoñez, Marta; Rivera, Io-Guané; Presa, Natalia; Gomez-Muñoz, Antonio

    2016-08-01

    Cell migration is a complex biological function involved in both physiologic and pathologic processes. Although this is a subject of intense investigation, the mechanisms by which cell migration is regulated are not completely understood. In this study we show that the bioactive sphingolipid ceramide 1-phosphate (C1P), which is involved in inflammatory responses, causes upregulation of metalloproteinases (MMP) -2 and -9 in J774A.1 macrophages. This effect was shown to be dependent on stimulation of phosphatidylinositol 3-kinase (PI3K) and extracellularly regulated kinases 1-2 (ERK1-2) as demonstrated by treating the cells with specific siRNA to knockdown the p85 regulatory subunit of PI3K, or ERK1-2. Inhibition of MMP-2 or MMP-9 pharmacologically or with specific siRNA to silence the genes encoding these MMPs abrogated C1P-stimulated macrophage migration. Also, C1P induced actin polymerization and potently increased phosphorylation of the focal adhesion protein paxillin, which are essential factors in the regulation of cell migration. As expected, blockade of paxillin activation with specific siRNA significantly reduced actin polymerization. In addition, inhibition of actin polymerization with cytochalasin D completely blocked C1P-induced MMP-2 and -9 expression as well as C1P-stimulated macrophage migration. It was also observed that pertussis toxin (Ptx) inhibited Akt, ERK1-2, and paxillin phosphorylation, and completely blocked cell migration. The latter findings support the notion that C1P-stimulated macrophage migration is a receptor mediated effect, and point to MMP-2 and -9 as possible therapeutic targets to control inflammation.

  6. MBTPS1/SKI-1/S1P proprotein convertase is required for ECM signaling and axial elongation during somitogenesis and vertebral development†

    PubMed Central

    Achilleos, Annita; Huffman, Nichole T.; Marcinkiewicyz, Edwidge; Seidah, Nabil G.; Chen, Qian; Dallas, Sarah L.; Trainor, Paul A.; Gorski, Jeff P.

    2015-01-01

    Caudal regression syndrome (sacral agenesis), which impairs development of the caudal region of the body, occurs with a frequency of about 2 live births per 100 000 newborns although this incidence rises to 1 in 350 infants born to mothers with gestational diabetes. The lower back and limbs can be affected as well as the genitourinary and gastrointestinal tracts. The axial skeleton is formed during embryogenesis through the process of somitogenesis in which the paraxial mesoderm periodically segments into bilateral tissue blocks, called somites. Somites are the precursors of vertebrae and associated muscle, tendons and dorsal dermis. Vertebral anomalies in caudal regression syndrome may arise through perturbation of somitogenesis or, alternatively, could result from defective bone formation and patterning. We discovered that MBTPS1/SKI-1/S1P, which proteolytically activates a class of transmembrane transcription factors, plays a critical role in somitogenesis and the pathogenesis of lumbar/sacral vertebral anomalies. Conditional deletion of Mbtps1 yields a viable mouse with misshapen, fused and reduced number of lumbar and sacral vertebrae, under-developed hind limb bones and a kinky, shortened tail. We show that Mbtps1 is required to (i) maintain the Fgf8 ‘wavefront’ in the presomitic mesoderm that underpins axial elongation, (ii) sustain the Lfng oscillatory ‘clock’ activity that governs the periodicity of somite formation and (iii) preserve the composition and character of the somitic extracellular matrix containing fibronectin, fibrillin2 and laminin. Based on this spinal phenotype and known functions of MBTPS1, we reason that loss-of-function mutations in Mbtps1 may cause the etiology of caudal regression syndrome. PMID:25652402

  7. Effects of synthetic sphingosine-1-phosphate analogs on cytosolic phospholipase A2alpha-independent release of arachidonic acid and cell toxicity in L929 fibrosarcoma cells: the structure-activity relationship.

    PubMed

    Shimizu, Masaya; Muramatsu, Yuki; Tada, Eiko; Kurosawa, Takeshi; Yamaura, Erika; Nakamura, Hiroyuki; Fujino, Hiromichi; Houjyo, Yuuya; Miyasaka, Yuri; Koide, Yuuki; Nishida, Atsushi; Murayama, Toshihiko

    2009-03-01

    Sphingolipid metabolites including ceramide, sphingosine, and their phosphorylated products [sphingosine-1-phosphate (S1P) and ceramide-1-phosphate] regulate cell functions including arachidonic acid (AA) metabolism and cell death. The development of analogs of S1P may be useful for regulating these mediator-induced cellular responses. We synthesized new analogs of S1P and examined their effects on the release of AA and cell death in L929 mouse fibrosarcoma cells. Among the analogs tested, several compounds including DMB-mC11S [dimethyl (2S,3R)-2-tert-butoxycarbonylamino-3-hydroxy-3-(3'-undecyl)phenylpropyl phosphate] and DMB-mC9S [dimethyl (2S,3R)-2-tert-butoxycarbonylamino-3-hydroxy-3-(3'-nonyl)phenylpropyl phosphate] released AA within 1 h and caused cell death 6 h after treatment. The release of AA was observed in C12 cells [a L929 variant lacking a type alpha cytosolic phospholipase A(2) (cPLA(2)alpha)] and L929-cPLAalpha-siRNA cells (L929 cells treated with small interference RNA for cPLA(2)alpha). Treatment with pharmacological inhibitors of secretory and Ca(2+)-independent PLA(2)s decreased the DMB-mC11S-induced release of AA. The effect of the S1P analogs tested on the release of AA was comparable to that on cell death in L929 cells, and a high correlation coefficient was observed. Two analogs lacking a butoxycarbonyl moiety [DMAc-mC11S (dimethyl (2S,3R)-2-acetamino-3-hydroxy-3-(3'-undecyl)phenylpropyl phosphate] and DMAm-mC11S [dimethyl (2S,3R)-2-amino-3-hydroxy-3-(3'-undecyl)phenylpropyl phosphate)] had inhibitory effects on the release of AA and cell toxicity induced by DMB-mC11S. Synthetic phosphorylated lipid analogs may be useful for studying PLA(2) activity and its toxicity in cells. [Supplementary Fig. 1: available only at http://dx.doi.org/10.1254/jphs.08284FP].

  8. Sphingomyelinase D Activity in Model Membranes: Structural Effects of in situ Generation of Ceramide-1-Phosphate

    PubMed Central

    Stock, Roberto P.; Brewer, Jonathan; Wagner, Kerstin; Ramos-Cerrillo, Blanca; Duelund, Lars; Jernshøj, Kit Drescher; Olsen, Lars Folke; Bagatolli, Luis A.

    2012-01-01

    The toxicity of Loxosceles spider venom has been attributed to a rare enzyme, sphingomyelinase D, which transforms sphingomyelin to ceramide-1-phosphate. The bases of its inflammatory and dermonecrotic activity, however, remain unclear. In this work the effects of ceramide-1-phosphate on model membranes were studied both by in situ generation of this lipid using a recombinant sphingomyelinase D from the spider Loxosceles laeta and by pre-mixing it with sphingomyelin and cholesterol. The systems of choice were large unilamellar vesicles for bulk studies (enzyme kinetics, fluorescence spectroscopy and dynamic light scattering) and giant unilamellar vesicles for fluorescence microscopy examination using a variety of fluorescent probes. The influence of membrane lateral structure on the kinetics of enzyme activity and the consequences of enzyme activity on the structure of target membranes containing sphingomyelin were examined. The findings indicate that: 1) ceramide-1-phosphate (particularly lauroyl ceramide-1-phosphate) can be incorporated into sphingomyelin bilayers in a concentration-dependent manner and generates coexistence of liquid disordered/solid ordered domains, 2) the activity of sphingomyelinase D is clearly influenced by the supramolecular organization of its substrate in membranes and, 3) in situ ceramide-1-phosphate generation by enzymatic activity profoundly alters the lateral structure and morphology of the target membranes. PMID:22558302

  9. Purification and properties of myo-inositol-1-phosphate dehydrogenase from germinating mung bean seeds.

    PubMed

    Ghosh, B; De, B P; Biswas, B B

    1984-01-01

    A novel enzyme, myo-inositol-1-phosphate dehydrogenase, which catalyzes the conversion of myo-inositol 1-phosphate to ribulose 5-phosphate has been purified 84-fold from mung bean seedling employing several common techniques. The molecular weight of this purified enzyme has been recorded as 88,500 by Sephadex G-200 column chromatography, and in sodium dodecyl sulfate-polyacrylamide gel electrophoresis one protein band containing three subunits of Mr 32,000 each was discernible. Km values for NAD+ and myo-inositol 1-phosphate have been recorded as 2.8 X 10(-4) and 5.0 X 10(-4) M, respectively. Production of NADH in myo-inositol-1-phosphate dehydrogenase reaction has also been evidenced by measurement of NADH fluorescence. Dehydrogenation and decarboxylation of myo-inositol 1-phosphate are mediated by the same enzyme. In fact, the rate of dehydrogenation corroborates with that of decarboxylation. Stoichiometry of this reaction suggests that for the production of 1 mol of ribulose 5-phosphate 2 mol of NAD+ are reduced.

  10. Transient receptor potential channel 1 maintains adherens junction plasticity by suppressing sphingosine kinase 1 expression to induce endothelial hyperpermeability.

    PubMed

    Tauseef, Mohammad; Farazuddin, Mohammad; Sukriti, Sukriti; Rajput, Charu; Meyer, James Otto; Ramasamy, Suresh Kumar; Mehta, Dolly

    2016-01-01

    Stability of endothelial cell (EC) adherens junctions (AJs) is central for prevention of tissue edema, the hallmark of chronic inflammatory diseases including acute respiratory distress syndrome. Here, we demonstrate a previously unsuspected role of sphingosine kinase 1 (SPHK1) in the mechanism by which transient receptor potential channel 1 (Trpc1)-mediated Ca(2+) entry destabilizes AJs. Trpc1(-/-) monolayers showed a 2.2-fold increase in vascular endothelial (VE)-cadherin cell-surface expression above wild-type (WT) monolayers. Thrombin increased endothelial permeability (evident by a 5-fold increase in interendothelial gap area and 60% decrease in transendothelial electrical resistance) in WT but not Trpc1(-/-) ECs. Trpc1(-/-) mice resisted the hyperpermeability effects of the edemagenic agonists used and exhibited 60% less endotoxin-induced mortality. Because sphingosine-1-phosphate (S1P) strengthens AJs, we determined if TRPC1 functioned by inhibiting SPHK1 activity, which generates S1P. Intriguingly, Trpc1(-/-) ECs or ECs transducing a TRPC1-inactive mutant showed a 1.5-fold increase in basal SPHK1 expression compared with WT ECs, resulting in a 2-fold higher S1P level. SPHK1 inhibitor SK1-I decreased basal transendothelial electrical resistance more in WT ECs (48 and 72% reduction at 20 and 50 μM, respectively) than in Trpc1(-/-) ECs. However, SK1-I pretreatment rescued thrombin-induced EC permeability in Trpc1(-/-) ECs. Thus, TRPC1 suppression of basal SPHK1 activity enables EC-barrier destabilization by edemagenic agonists. PMID:26316271

  11. A Biochemical Approach to Understand the Pathogenesis of Advanced Pulmonary Arterial Hypertension: Metabolomic Profiles of Arginine, Sphingosine-1-Phosphate, and Heme of Human Lung

    PubMed Central

    Zhao, Yidan D.; Chu, Lei; Lin, Kathleen; Granton, Elise; Yin, Li; Peng, Jenny; Hsin, Michael; Wu, Licun; Yu, Amy; Waddell, Thomas; Keshavjee, Shaf; Granton, John; de Perrot, Marc

    2015-01-01

    Pulmonary arterial hypertension (PAH) is a vascular disease characterized by persistent precapillary pulmonary hypertension (PH), leading to progressive right heart failure and premature death. The pathological mechanisms underlying this condition remain elusive. Analysis of global metabolomics from lung tissue of patients with PAH (n = 8) and control lung tissue (n = 8) leads to a better understanding of disease progression. Using a combination of high-throughput liquid-and-gas-chromatography-based mass spectrometry, we showed unbiased metabolomic profiles of disrupted arginine pathways with increased Nitric oxide (NO) and decreased arginine. Our results also showed specific metabolic pathways and genetic profiles with increased Sphingosine-1-phosphate (S1P) metabolites as well as increased Heme metabolites with altered oxidative pathways in the advanced stage of the human PAH lung. The results suggest that PAH has specific metabolic pathways contributing to the vascular remodeling in severe pulmonary hypertension. Profiling metabolomic alterations of the PAH lung has provided a new understanding of the pathogenic mechanisms of PAH, which benefits therapeutic targeting to specific metabolic pathways involved in the progression of PAH. PMID:26317340

  12. Lysophospholipid receptors LPA1–3 are not required for the inhibitory effects of LPA on mouse retinal growth cones

    PubMed Central

    Birgbauer, Eric; Chun, Jerold

    2016-01-01

    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. PMID:26966392

  13. 21 CFR 862.1315 - Galactose-1-phosphate uridyl transferase test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Galactose-1-phosphate uridyl transferase test system. 862.1315 Section 862.1315 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... hereditary disease galactosemia (disorder of galactose metabolism) in infants. (b) Classification. Class II....

  14. 21 CFR 862.1315 - Galactose-1-phosphate uridyl transferase test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Galactose-1-phosphate uridyl transferase test system. 862.1315 Section 862.1315 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1315...

  15. A comparison of sugar indicators enables a universal high-throughput sugar-1-phosphate nucleotidyltransferase assay

    PubMed Central

    Moretti, Rocco; Thorson, Jon S.

    2008-01-01

    A systematic comparison of six sugar indicators for their sensitivity, specificity, cross reactivity and suitability in the context of crude lysates revealed para-hydroxybenzoic acid hydrazide (pHBH) to be best suited for application in a plate-based phosphatase-assisted universal sugar-1-phosphate nucleotidyltransferase assay. The addition of a general phosphatase to nucleotidyltransferase reaction aliquots enabled the conversion of remaining sugar-1-phosphate to free sugar, the concentration of which could be rapidly assessed via the pHBH assay. The assay was validated using the model glucose-1-phosphate thymidylyltransferase from Salmonella enterica (RmlA) and compared favorably to a previously reported HPLC assay. This coupled discontinuous assay is quantitative, high-throughput and robust; relies only on commercially available enzymes and reagents; does not require chromatography, specialized detectors (e.g. mass or evaporative light scattering detectors) or radioisotopes; and is capable of detecting less than 5 nmol of sugar-1-phosphate. It is anticipated this high throughput assay system will greatly facilitate nucleotidyltransferase mechanistic and directed evolution/engineering studies. PMID:18387352

  16. beta-D-Glucose 1-phosphate. A structural unit and an immunological determinant of a glycan from streptococcal cell walls.

    PubMed

    Pazur, J H

    1982-01-25

    Glycose 1-phosphate moieties are emerging as important structural units of macromolecular substances imparting special biological functions to these molecules. In the present study, beta-D-glucose 1-phosphate moieties are shown to be structural units and immunological determinants of a bacterial glycan. The glycan is a tetraheteroglycan from the cell wall of Streptococcus faecalis, strain N and is composed of glucose, galactose, rhamnose, N-acetylgalactosamine, and phosphate. Several lines of evidence have been obtained for the presence of beta-D-glucose 1-phosphate units in the glycan, including the liberation of glucose by mild acid hydrolysis, the inhibition of the precipitin reaction by beta-D-glucose 1-phosphate, and the formation of levoglucosan on treatment of the glycan with alkali. Work on the preparation of affinity adsorbents for isolating the new types of antibodies directed at the beta-D-glucose 1-phosphate moieties is in progress. PMID:6172422

  17. Deletion of Mbtps1 (Pcsk8, S1p, Ski-1) Gene in Osteocytes Stimulates Soleus Muscle Regeneration and Increased Size and Contractile Force with Age.

    PubMed

    Gorski, Jeff P; Huffman, Nichole T; Vallejo, Julian; Brotto, Leticia; Chittur, Sridar V; Breggia, Anne; Stern, Amber; Huang, Jian; Mo, Chenglin; Seidah, Nabil G; Bonewald, Lynda; Brotto, Marco

    2016-02-26

    Conditional deletion of Mbtps1 (cKO) protease in bone osteocytes leads to an age-related increase in mass (12%) and in contractile force (30%) in adult slow twitch soleus muscles (SOL) with no effect on fast twitch extensor digitorum longus muscles. Surprisingly, bone from 10-12-month-old cKO animals was indistinguishable from controls in size, density, and morphology except for a 25% increase in stiffness. cKO SOL exhibited increased expression of Pax7, Myog, Myod1, Notch, and Myh3 and 6-fold more centralized nuclei, characteristics of postnatal regenerating muscle, but only in type I myosin heavy chain-expressing cells. Increased expression of gene pathways mediating EGF receptor signaling, circadian exercise, striated muscle contraction, and lipid and carbohydrate oxidative metabolism were also observed in cKO SOL. This muscle phenotype was not observed in 3-month-old mice. Although Mbtps1 mRNA and protein expression was reduced in cKO bone osteocytes, no differences in Mbtps1 or cre recombinase expression were observed in cKO SOL, explaining this age-related phenotype. Understanding bone-muscle cross-talk may provide a fresh and novel approach to prevention and treatment of age-related muscle loss. PMID:26719336

  18. Characterization of mRNA expression for the endothelial differentiation G-protein-coupled (EDG) receptors in porcine endometrial tissue during the pre-implantation period of pregnancy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Establishment of pregnancy in the pig requires proper preparation of the uterine environment. Although the mechanisms by which the endometrium undergoes preparation for embryo implantation are not clear, recent evidence has suggested that lysophospholipids, such as sphingosine 1-phosphate (S1P) and ...

  19. Studies of inositol 1-phosphate analogues as inhibitors of the phosphatidylinositol phosphate synthase in mycobacteria.

    PubMed

    Morii, Hiroyuki; Okauchi, Tatsuo; Nomiya, Hiroki; Ogawa, Midori; Fukuda, Kazumasa; Taniguchi, Hatsumi

    2013-03-01

    We previously reported a novel pathway for the biosynthesis of phosphatidylinositol in mycobacteria via phosphatidylinositol phosphate (PIP) [Morii H., Ogawa, M., Fukuda, K., Taniguchi, H., and Koga, Y (2010) J. Biochem. 148, 593-602]. PIP synthase in the pathway is a promising target for the development of new anti-mycobacterium drugs. In the present study, we evaluated the characteristics of the PIP synthase of Mycobacterium tuberculosis. Four types of compounds were chemically synthesized based on the assumption that structural homologues of inositol 1-phosphate, a PIP synthase substrate, would act as PIP synthase inhibitors, and the results confirmed that all synthesized compounds inhibited PIP synthase activity. The phosphonate analogue of inositol 1-phosphate (Ino-C-P) had the greatest inhibitory effect among the synthesized compounds examined. Kinetic analysis indicated that Ino-C-P acted as a competitive inhibitor of inositol 1-phosphate. The IC(50) value for Ino-C-P inhibition of the PIP synthase activity was estimated to be 2.0 mM. Interestingly, Ino-C-P was utilized in the same manner as the normal PIP synthase substrate, leading to the synthesis of a phosphonate analogue of PIP (PI-C-P), which had a structure similar to that of the natural product, PIP. In addition, PI-C-P had high inhibitory activity against PIP synthase.

  20. Molecular cloning and characterization of L-galactose-1-phosphate phosphatase from tobacco (Nicotiana tabacum).

    PubMed

    Sakamoto, Shingo; Fujikawa, Yukichi; Tanaka, Nobukazu; Esaka, Muneharu

    2012-01-01

    L-Galactose-1-phosphate phosphatase (GPPase) is an enzyme involved in ascorbate biosynthesis in higher plants. We isolated a cDNA encoding GPPase from tobacco, and named it NtGPPase. The putative amino acid sequence of NtGPPase contained inositol monophosphatase motifs and metal binding sites. Recombinant NtGPPase hydrolyzed not only L-galactose-1-phosphate, but also myo-inositol-1-phosphate. The optimum pH for the GPPase activity of NtGPPase was 7.5. Its enzyme activity required Mg2+, and was inhibited by Li+ and Ca2+. Its fluorescence, fused with green fluorescence protein in onion cells and protoplasts of tobacco BY-2 cells, was observed in both the cytosol and nucleus. The expression of NtGPPase mRNA and protein was clearly correlated with L-ascorbic acid (AsA) contents of BY-2 cells during culture. The AsA contents of NtGPPase over expression lines were higher than those of empty lines at 13 d after subculture. This suggests that NtGPPase contributes slightly to AsA biosynthesis. PMID:22790939

  1. Lysophospholipid receptors in drug discovery

    PubMed Central

    Kihara, Yasuyuki; Mizuno, Hirotaka; Chun, Jerold

    2014-01-01

    Lysophospholipids (LPs), including lysophosphatidic acid (LPA), sphingosine 1-phospate (S1P), lysophosphatidylinositol (LPI), and lysophosphatidylserine (LysoPS), are bioactive lipids that transduce signals through their specific cell-surface G protein-coupled receptors, LPA1–6, S1P1–5, LPI1, and LysoPS1–3, respectively. These LPs and their receptors have been implicated in both physiological and pathophysiological processes such as autoimmune diseases, neurodegenerative diseases, fibrosis, pain, cancer, inflammation, metabolic syndrome, bone formation, fertility, organismal development, and other effects on most organ systems. Advances in the LP receptor field have enabled the development of novel small molecules targeting LP receptors for several diseases. Most notably, fingolimod (FTY720, Gilenya, Novartis), an S1P receptor modulator, became the first FDA-approved medicine as an orally bioavailable drug for treating relapsing forms of multiple sclerosis. This success is currently being followed by multiple, mechanistically related compounds targeting S1P receptor subtypes, which are in various stages of clinical development. In addition, an LPA1 antagonist, BMS-986020 (Bristol-Myers Squibb), is in Phase 2 clinical development for treating idiopathic pulmonary fibrosis, as is a distinct compound, SAR100842 (Sanofi) for the treatment of systemic sclerosis and related fibrotic diseases. This review summarizes the current state of drug discovery in the LP receptor field. PMID:25499971

  2. Lysophospholipid receptors in drug discovery.

    PubMed

    Kihara, Yasuyuki; Mizuno, Hirotaka; Chun, Jerold

    2015-05-01

    Lysophospholipids (LPs), including lysophosphatidic acid (LPA), sphingosine 1-phospate (S1P), lysophosphatidylinositol (LPI), and lysophosphatidylserine (LysoPS), are bioactive lipids that transduce signals through their specific cell-surface G protein-coupled receptors, LPA1-6, S1P1-5, LPI1, and LysoPS1-3, respectively. These LPs and their receptors have been implicated in both physiological and pathophysiological processes such as autoimmune diseases, neurodegenerative diseases, fibrosis, pain, cancer, inflammation, metabolic syndrome, bone formation, fertility, organismal development, and other effects on most organ systems. Advances in the LP receptor field have enabled the development of novel small molecules targeting LP receptors for several diseases. Most notably, fingolimod (FTY720, Gilenya, Novartis), an S1P receptor modulator, became the first FDA-approved medicine as an orally bioavailable drug for treating relapsing forms of multiple sclerosis. This success is currently being followed by multiple, mechanistically related compounds targeting S1P receptor subtypes, which are in various stages of clinical development. In addition, an LPA1 antagonist, BMS-986020 (Bristol-Myers Squibb), is in Phase 2 clinical development for treating idiopathic pulmonary fibrosis, as a distinct compound, SAR100842 (Sanofi) for the treatment of systemic sclerosis and related fibrotic diseases. This review summarizes the current state of drug discovery in the LP receptor field. PMID:25499971

  3. The cause of hepatic accumulation of fructose 1-phosphate on fructose loading

    PubMed Central

    Woods, H. F.; Eggleston, L. V.; Krebs, H. A.

    1970-01-01

    1. The changes in the metabolite content in freeze-clamped livers of fed rats occurring on perfusion with 10mm-d-fructose have been examined. 2. The most striking effects of fructose were an accumulation of fructose 1-phosphate, as already known, up to 8.7μmol/g of liver within 10min, a loss of total adenine nucleotides (up to 35% after 40min) with a decrease in the ATP content to 23% within 10min, a sevenfold rise in the concentration of IMP to 1.1μmol/g and an eightfold rise of α-glycerophosphate to 1.1μmol/g. 3. There was a transient decrease in Pi from 4.2 to 1.7μmol/g. Within 40min the Pi content recovered to the normal value, probably because of an uptake of Pi from the perfusion medium. 4. The degradation of the adenine nucleotides beyond the stage of AMP can be accounted for by the decrease of ATP and Pi. As ATP inhibits 5-nucleotidase, and as Pi inhibits AMP deaminase any AMP arising in the tissue is liable to undergo dephosphorylation or deamination under the conditions occurring after fructose loading. 5. The content of lactate increased to 4.3μmol/g at 80min; pyruvate also increased and the [lactate]/[pyruvate] ratio remained within physiological limits. 6. The concentration of free fructose within the liver remained much below that in the perfusion medium, indicating that the rate of penetration of fructose into the tissue was lower than the rate of utilization. 7. The fission of fructose 1-phosphate by liver aldolase is inhibited by several phosphorylated intermediates, especially by IMP. This inhibition is competitive with a Ki of 0.1mm. 8. The maximal rates of the enzymes synthesizing and splitting fructose 1-phosphate are about equal. The accumulation of fructose 1-phosphate on fructose loading is due to the inhibition of the fission of fructose 1-phosphate by the IMP arising from the degradation of the adenine nucleotides. PMID:5500310

  4. Sphingosine-1-Phosphate Lyase Deficient Cells as a Tool to Study Protein Lipid Interactions

    PubMed Central

    Gerl, Mathias J.; Bittl, Verena; Kirchner, Susanne; Sachsenheimer, Timo; Brunner, Hanna L.; Lüchtenborg, Christian; Özbalci, Cagakan; Wiedemann, Hannah; Wegehingel, Sabine; Nickel, Walter; Haberkant, Per; Schultz, Carsten; Krüger, Marcus; Brügger, Britta

    2016-01-01

    Cell membranes contain hundreds to thousands of individual lipid species that are of structural importance but also specifically interact with proteins. Due to their highly controlled synthesis and role in signaling events sphingolipids are an intensely studied class of lipids. In order to investigate their metabolism and to study proteins interacting with sphingolipids, metabolic labeling based on photoactivatable sphingoid bases is the most straightforward approach. In order to monitor protein-lipid-crosslink products, sphingosine derivatives containing a reporter moiety, such as a radiolabel or a clickable group, are used. In normal cells, degradation of sphingoid bases via action of the checkpoint enzyme sphingosine-1-phosphate lyase occurs at position C2-C3 of the sphingoid base and channels the resulting hexadecenal into the glycerolipid biosynthesis pathway. In case the functionalized sphingosine looses the reporter moiety during its degradation, specificity towards sphingolipid labeling is maintained. In case degradation of a sphingosine derivative does not remove either the photoactivatable or reporter group from the resulting hexadecenal, specificity towards sphingolipid labeling can be achieved by blocking sphingosine-1-phosphate lyase activity and thus preventing sphingosine derivatives to be channeled into the sphingolipid-to-glycerolipid metabolic pathway. Here we report an approach using clustered, regularly interspaced, short palindromic repeats (CRISPR)-associated nuclease Cas9 to create a sphingosine-1-phosphate lyase (SGPL1) HeLa knockout cell line to disrupt the sphingolipid-to-glycerolipid metabolic pathway. We found that the lipid and protein compositions as well as sphingolipid metabolism of SGPL1 knock-out HeLa cells only show little adaptations, which validates these cells as model systems to study transient protein-sphingolipid interactions. PMID:27100999

  5. Synthesis of arabinitol 1-phosphate and its use for characterization of arabinitol-phosphate dehydrogenase.

    PubMed

    Soroka, Nikolai V; Kulminskaya, Anna A; Eneyskaya, Elena V; Shabalin, Konstantin A; Uffimtcev, Andrei V; Povelainen, Mira; Miasnikov, Andrei N; Neustroev, Kirill N

    2005-03-21

    D-arabinitol 1-phosphate (Ara-ol1-P), a substrate for D-arabinitol-phosphate dehydrogenase (APDH), was chemically synthesized from D-arabinonic acid in five steps (O-acetylation, chlorination, reduction, phosphorylation, and de-O-acetylation). Ara-ol1-P was used as a substrate for the characterization of APDH from Bacillus halodurans. APDH converts Ara-ol1-P to xylulose 5-phosphate in the oxidative reaction; both NAD(+) and NADP(+) were accepted as co-factors. Kinetic parameters for the oxidative and reductive reactions are consistent with a ternary complex mechanism.

  6. The pathway of ligand entry from the membrane bilayer to a lipid G protein-coupled receptor

    PubMed Central

    Stanley, Nathaniel; Pardo, Leonardo; Fabritiis, Gianni De

    2016-01-01

    The binding process through the membrane bilayer of lipid-like ligands to a protein target is an important but poorly explored recognition process at the atomic level. In this work we succeeded in resolving the binding of the lipid inhibitor ML056 to the sphingosine-1-phosphate receptor 1 (S1P1R) using unbiased molecular dynamics simulations with an aggregate sampling of over 800 μs. The binding pathway is a multi-stage process consisting of the ligand diffusing in the bilayer leaflet to contact a “membrane vestibule” at the top of TM 7, subsequently moving from this lipid-facing vestibule to the orthosteric binding cavity through a channel formed by TMs 1 and 7 and the N-terminal of the receptor. Unfolding of the N-terminal alpha-helix increases the volume of the channel upon ligand entry, helping to reach the crystallographic pose that also corresponds to the predicted favorable pose. The relaxation timescales of the binding process show that the binding of the ligand to the “membrane vestibule” is the rate-limiting step in the multi microseconds timescale. We comment on the significance and parallels of the binding process in the context of other binding studies. PMID:26940769

  7. Structure and catalytic mechanism of L-rhamnulose-1-phosphate aldolase.

    PubMed

    Kroemer, Markus; Merkel, Iris; Schulz, Georg E

    2003-09-16

    The structure of L-rhamnulose-1-phosphate aldolase has been established at 1.35 A resolution in a crystal form that was obtained by a surface mutation and has one subunit of the C(4)-symmetric tetramer in the asymmetric unit. It confirms an earlier 2.7 A resolution structure which was determined in a complicated crystal form with 20 subunits per asymmetric unit. The chain fold and the active center are similar to those of L-fuculose-1-phosphate aldolase and L-ribulose-5-phosphate 4-epimerase. The active center similarity is supported by a structural comparison of all three enzymes and by the binding mode of the inhibitor phosphoglycolohydroxamate at the site of the product dihydroxyacetone phosphate for the two aldolases. The sensitivity of the catalytic rate to several mutations and a comparison with the established mechanism of the related aldolase give rise to a putative catalytic mechanism. This mechanism involves the same binding mode of the second product L-lactaldehyde in both aldolases, except for a 180 degrees flip of the aldehyde group distinguishing between the two epimers rhamnulose and fuculose. The N-terminal domain exhibits a correlated anisotropic mobility that channels the isotropic Brownian motion into a directed movement of the catalytic base and the substrate phosphate on the N-domain toward the zinc ion and the lactaldehyde on the C-terminal domain. We suggest that this movement supports the catalysis mechanically.

  8. Allosteric competitive inhibitors of the glucose-1-phosphate thymidylyltransferase (RmlA) from Pseudomonas aeruginosa.

    PubMed

    Alphey, Magnus S; Pirrie, Lisa; Torrie, Leah S; Boulkeroua, Wassila Abdelli; Gardiner, Mary; Sarkar, Aurijit; Maringer, Marko; Oehlmann, Wulf; Brenk, Ruth; Scherman, Michael S; McNeil, Michael; Rejzek, Martin; Field, Robert A; Singh, Mahavir; Gray, David; Westwood, Nicholas J; Naismith, James H

    2013-02-15

    Glucose-1-phosphate thymidylyltransferase (RmlA) catalyzes the condensation of glucose-1-phosphate (G1P) with deoxy-thymidine triphosphate (dTTP) to yield dTDP-d-glucose and pyrophosphate. This is the first step in the l-rhamnose biosynthetic pathway. l-Rhamnose is an important component of the cell wall of many microorganisms, including Mycobacterium tuberculosis and Pseudomonas aeruginosa. Here we describe the first nanomolar inhibitors of P. aeruginosa RmlA. These thymine analogues were identified by high-throughput screening and subsequently optimized by a combination of protein crystallography, in silico screening, and synthetic chemistry. Some of the inhibitors show inhibitory activity against M. tuberculosis. The inhibitors do not bind at the active site of RmlA but bind at a second site remote from the active site. Despite this, the compounds act as competitive inhibitors of G1P but with high cooperativity. This novel behavior was probed by structural analysis, which suggests that the inhibitors work by preventing RmlA from undergoing the conformational change key to its ordered bi-bi mechanism.

  9. Molecular basis of classic galactosemia from the structure of human galactose 1-phosphate uridylyltransferase

    PubMed Central

    McCorvie, Thomas J.; Kopec, Jolanta; Pey, Angel L.; Fitzpatrick, Fiona; Patel, Dipali; Chalk, Rod; Shrestha, Leela; Yue, Wyatt W.

    2016-01-01

    Classic galactosemia is a potentially lethal disease caused by the dysfunction of galactose 1-phosphate uridylyltransferase (GALT). Over 300 disease-associated GALT mutations have been reported, with the majority being missense changes, although a better understanding of their underlying molecular effects has been hindered by the lack of structural information for the human enzyme. Here, we present the 1.9 Å resolution crystal structure of human GALT (hGALT) ternary complex, revealing a homodimer arrangement that contains a covalent uridylylated intermediate and glucose-1-phosphate in the active site, as well as a structural zinc-binding site, per monomer. hGALT reveals significant structural differences from bacterial GALT homologues in metal ligation and dimer interactions, and therefore is a zbetter model for understanding the molecular consequences of disease mutations. Both uridylylation and zinc binding influence the stability and aggregation tendency of hGALT. This has implications for disease-associated variants where p.Gln188Arg, the most commonly detected, increases the rate of aggregation in the absence of zinc likely due to its reduced ability to form the uridylylated intermediate. As such our structure serves as a template in the future design of pharmacological chaperone therapies and opens new concepts about the roles of metal binding and activity in protein misfolding by disease-associated mutants. PMID:27005423

  10. The Sphingosine-1-Phosphate Lyase (LegS2) Contributes to the Restriction of Legionella pneumophila in Murine Macrophages

    PubMed Central

    Abu Khweek, Arwa; Kanneganti, Apurva; C. Guttridge D, Denis; Amer, Amal O.

    2016-01-01

    L. pneumophila is the causative agent of Legionnaires’ disease, a human illness characterized by severe pneumonia. In contrast to those derived from humans, macrophages derived from most mouse strains restrict L. pneumophila replication. The restriction of L. pneumophila replication has been shown to require bacterial flagellin, a component of the type IV secretion system as well as the cytosolic NOD-like receptor (NLR) Nlrc4/ Ipaf. These events lead to caspase-1 activation which, in turn, activates caspase-7. Following caspase-7 activation, the phagosome-containing L. pneumophila fuses with the lysosome, resulting in the restriction of L. pneumophila growth. The LegS2 effector is injected by the type IV secretion system and functions as a sphingosine 1-phosphate lyase. It is homologous to the eukaryotic sphingosine lyase (SPL), an enzyme required in the terminal steps of sphingolipid metabolism. Herein, we show that mice Bone Marrow-Derived Macrophages (BMDMs) and human Monocyte-Derived Macrophages (hMDMs) are more permissive to L. pneumophila legS2 mutants than wild-type (WT) strains. This permissiveness to L. pneumophila legS2 is neither attributed to abolished caspase-1, caspase-7 or caspase-3 activation, nor due to the impairment of phagosome-lysosome fusion. Instead, an infection with the legS2 mutant resulted in the reduction of some inflammatory cytokines and their corresponding mRNA; this effect is mediated by the inhibition of the nuclear transcription factor kappa-B (NF-κB). Moreover, BMDMs infected with L. pneumophila legS2 mutant showed elongated mitochondria that resembles mitochondrial fusion. Therefore, the absence of LegS2 effector is associated with reduced NF-κB activation and atypical morphology of mitochondria. PMID:26741365

  11. Sphingosylphosphorylcholine and lysophosphatidylcholine are ligands for the G protein-coupled receptor GPR4.

    PubMed

    Zhu, K; Baudhuin, L M; Hong, G; Williams, F S; Cristina, K L; Kabarowski, J H; Witte, O N; Xu, Y

    2001-11-01

    Sphingosylphosphorylcholine (SPC) and lysophosphatidylcholine (LPC) are bioactive lipid molecules involved in numerous biological processes. We have recently identified ovarian cancer G protein-coupled receptor 1 (OGR1) as a specific and high affinity receptor for SPC, and G2A as a receptor with high affinity for LPC, but low affinity for SPC. Among G protein-coupled receptors, GPR4 shares highest sequence homology with OGR1 (51%). In this work, we have identified GPR4 as not only another high affinity receptor for SPC, but also a receptor for LPC, albeit of lower affinity. Both SPC and LPC induce increases in intracellular calcium concentration in GPR4-, but not vector-transfected MCF10A cells. These effects are insensitive to treatment with BN52021, WEB-2170, and WEB-2086 (specific platelet activating factor (PAF) receptor antagonists), suggesting that they are not mediated through an endogenous PAF receptor. SPC and LPC bind to GPR4 in GPR4-transfected CHO cells with K(d)/SPC = 36 nm, and K(d)/LPC = 159 nm, respectively. Competitive binding is elicited only by SPC and LPC. Both SPC and LPC activate GPR4-dependent activation of serum response element reporter and receptor internalization. Swiss 3T3 cells expressing GPR4 respond to both SPC and LPC, but not sphingosine 1-phosphate (S1P), PAF, psychosine (Psy), glucosyl-beta1'1-sphingosine (Glu-Sph), galactosyl-beta1'1-ceramide (Gal-Cer), or lactosyl-beta1'1-ceramide (Lac-Cer) to activate extracellular signal-regulated kinase mitogen-activated protein kinase in a concentration- and time-dependent manner. SPC and LPC stimulate DNA synthesis in GPR4-expressing Swiss 3T3 cells. Both extracellular signal-regulated kinase activation and DNA synthesis stimulated by SPC and LPC are pertussis toxin-sensitive, suggesting the involvement of a G(i)-heterotrimeric G protein. In addition, GPR4 expression confers chemotactic responses to both SPC and LPC in Swiss 3T3 cells. Taken together, our data indicate that GPR4 is a

  12. Chemokine Receptors, CXCR1 and CXCR2, Differentially Regulate Exosome Release in Hepatocytes.

    PubMed

    Nojima, Hiroyuki; Konishi, Takanori; Freeman, Christopher M; Schuster, Rebecca M; Japtok, Lukasz; Kleuser, Burkhard; Edwards, Michael J; Gulbins, Erich; Lentsch, Alex B

    2016-01-01

    Exosomes are small membrane vesicles released by different cell types, including hepatocytes, that play important roles in intercellular communication. We have previously demonstrated that hepatocyte-derived exosomes contain the synthetic machinery to form sphingosine-1-phosphate (S1P) in target hepatocytes resulting in proliferation and liver regeneration after ischemia/reperfusion (I/R) injury. We also demonstrated that the chemokine receptors, CXCR1 and CXCR2, regulate liver recovery and regeneration after I/R injury. In the current study, we sought to determine if the regulatory effects of CXCR1 and CXCR2 on liver recovery and regeneration might occur via altered release of hepatocyte exosomes. We found that hepatocyte release of exosomes was dependent upon CXCR1 and CXCR2. CXCR1-deficient hepatocytes produced fewer exosomes, whereas CXCR2-deficient hepatocytes produced more exosomes compared to their wild-type controls. In CXCR2-deficient hepatocytes, there was increased activity of neutral sphingomyelinase (Nsm) and intracellular ceramide. CXCR1-deficient hepatocytes had no alterations in Nsm activity or ceramide production. Interestingly, exosomes from CXCR1-deficient hepatocytes had no effect on hepatocyte proliferation, due to a lack of neutral ceramidase and sphingosine kinase. The data demonstrate that CXCR1 and CXCR2 regulate hepatocyte exosome release. The mechanism utilized by CXCR1 remains elusive, but CXCR2 appears to modulate Nsm activity and resultant production of ceramide to control exosome release. CXCR1 is required for packaging of enzymes into exosomes that mediate their hepatocyte proliferative effect. PMID:27551720

  13. Chemokine Receptors, CXCR1 and CXCR2, Differentially Regulate Exosome Release in Hepatocytes

    PubMed Central

    Nojima, Hiroyuki; Konishi, Takanori; Freeman, Christopher M.; Schuster, Rebecca M.; Japtok, Lukasz; Kleuser, Burkhard; Edwards, Michael J.; Gulbins, Erich; Lentsch, Alex B.

    2016-01-01

    Exosomes are small membrane vesicles released by different cell types, including hepatocytes, that play important roles in intercellular communication. We have previously demonstrated that hepatocyte-derived exosomes contain the synthetic machinery to form sphingosine-1-phosphate (S1P) in target hepatocytes resulting in proliferation and liver regeneration after ischemia/reperfusion (I/R) injury. We also demonstrated that the chemokine receptors, CXCR1 and CXCR2, regulate liver recovery and regeneration after I/R injury. In the current study, we sought to determine if the regulatory effects of CXCR1 and CXCR2 on liver recovery and regeneration might occur via altered release of hepatocyte exosomes. We found that hepatocyte release of exosomes was dependent upon CXCR1 and CXCR2. CXCR1-deficient hepatocytes produced fewer exosomes, whereas CXCR2-deficient hepatocytes produced more exosomes compared to their wild-type controls. In CXCR2-deficient hepatocytes, there was increased activity of neutral sphingomyelinase (Nsm) and intracellular ceramide. CXCR1-deficient hepatocytes had no alterations in Nsm activity or ceramide production. Interestingly, exosomes from CXCR1-deficient hepatocytes had no effect on hepatocyte proliferation, due to a lack of neutral ceramidase and sphingosine kinase. The data demonstrate that CXCR1 and CXCR2 regulate hepatocyte exosome release. The mechanism utilized by CXCR1 remains elusive, but CXCR2 appears to modulate Nsm activity and resultant production of ceramide to control exosome release. CXCR1 is required for packaging of enzymes into exosomes that mediate their hepatocyte proliferative effect. PMID:27551720

  14. Sphingosine-1-phosphate lyase in development and disease: sphingolipid metabolism takes flight.

    PubMed

    Fyrst, Henrik; Saba, Julie D

    2008-09-01

    Sphingosine-1-phosphate lyase (SPL) is a highly conserved enzyme that catalyses the final step of sphingolipid degradation, namely the irreversible cleavage of the carbon chain at positions 2-3 of a long-chain base phosphate (LCBP), thereby yielding a long-chain aldehyde and phosphoethanolamine. LCBPs are potent signaling molecules involved in cell proliferation, survival, migration, cell-cell interactions and cell stress responses. Therefore, tight regulation of LCBP signaling is required for proper cell function, and perturbations of this system can lead to alterations in biological processes including development, reproduction and physiology. SPL is a key enzyme in regulating the intracellular and circulating levels of LCBPs and is, therefore, gaining attention as a putative target for pharmacological intervention. This review provides an overview of our current understanding of SPL structure and function, mechanisms involved in SPL regulation and the role of SPL in development and disease.

  15. Molecular and biochemical characterization of mannitol-1-phosphate dehydrogenase from the model brown alga Ectocarpus sp.

    PubMed

    Bonin, Patricia; Groisillier, Agnès; Raimbault, Alice; Guibert, Anaïs; Boyen, Catherine; Tonon, Thierry

    2015-09-01

    The sugar alcohol mannitol is important in the food, pharmaceutical, medical and chemical industries. It is one of the most commonly occurring polyols in nature, with the exception of Archaea and animals. It has a range of physiological roles, including as carbon storage, compatible solute, and osmolyte. Mannitol is present in large amounts in brown algae, where its synthesis involved two steps: a mannitol-1-phosphate dehydrogenase (M1PDH) catalyzes a reversible reaction between fructose-6-phosphate (F6P) and mannitol-1-phosphate (M1P) (EC 1.1.1.17), and a mannitol-1-phosphatase hydrolyzes M1P to mannitol (EC 3.1.3.22). Analysis of the model brown alga Ectocarpus sp. genome provided three candidate genes for M1PDH activities. We report here the sequence analysis of Ectocarpus M1PDHs (EsM1PDHs), and the biochemical characterization of the recombinant catalytic domain of EsM1PDH1 (EsM1PDH1cat). Ectocarpus M1PDHs are representatives of a new type of modular M1PDHs among the polyol-specific long-chain dehydrogenases/reductases (PSLDRs). The N-terminal domain of EsM1PDH1 was not necessary for enzymatic activity. Determination of kinetic parameters indicated that EsM1PDH1cat displayed higher catalytic efficiency for F6P reduction compared to M1P oxidation. Both activities were influenced by NaCl concentration and inhibited by the thioreactive compound pHMB. These observations were completed by measurement of endogenous M1PDH activity and of EsM1PDH gene expression during one diurnal cycle. No significant changes in enzyme activity were monitored between day and night, although transcription of two out of three genes was altered, suggesting different levels of regulation for this key metabolic pathway in brown algal physiology. PMID:26232554

  16. Method to simultaneously determine the sphingosine 1-phosphate breakdown product (2E)-hexadecenal and its fatty acid derivatives using isotope-dilution HPLC-electrospray ionization-quadrupole/time-of-flight mass spectrometry.

    PubMed

    Neuber, Corinna; Schumacher, Fabian; Gulbins, Erich; Kleuser, Burkhard

    2014-09-16

    Sphingosine 1-phosphate (S1P), a bioactive lipid involved in various physiological processes, can be irreversibly degraded by the membrane-bound S1P lyase (S1PL) yielding (2E)-hexadecenal and phosphoethanolamine. It is discussed that (2E)-hexadecenal is further oxidized to (2E)-hexadecenoic acid by the long-chain fatty aldehyde dehydrogenase ALDH3A2 (also known as FALDH) prior to activation via coupling to coenzyme A (CoA). Inhibition or defects in these enzymes, S1PL or FALDH, result in severe immunological disorders or the Sjögren-Larsson syndrome, respectively. Hence, it is of enormous importance to simultaneously determine the S1P breakdown product (2E)-hexadecenal and its fatty acid metabolites in biological samples. However, no method is available so far. Here, we present a sensitive and selective isotope-dilution high performance liquid chromatography-electrospray ionization-quadrupole/time-of-flight mass spectrometry method for simultaneous quantification of (2E)-hexadecenal and its fatty acid metabolites following derivatization with 2-diphenylacetyl-1,3-indandione-1-hydrazone and 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide. Optimized conditions for sample derivatization, chromatographic separation, and MS/MS detection are presented as well as an extensive method validation. Finally, our method was successfully applied to biological samples. We found that (2E)-hexadecenal is almost quantitatively oxidized to (2E)-hexadecenoic acid, that is further activated as verified by cotreatment of HepG2 cell lysates with (2E)-hexadecenal and the acyl-CoA synthetase inhibitor triacsin C. Moreover, incubations of cell lysates with deuterated (2E)-hexadecenal revealed that no hexadecanoic acid is formed from the aldehyde. Thus, our method provides new insights into the sphingolipid metabolism and will be useful to investigate diseases known for abnormalities in long-chain fatty acid metabolism, e.g., the Sjögren-Larsson syndrome, in more detail. PMID:25137547

  17. Inhibitors of acetyltransferase domain of N-acetylglucosamine-1-phosphate-uridyltransferase/glucosamine-1-phosphate-acetyltransferase (GlmU). Part 1: Hit to lead evaluation of a novel arylsulfonamide series.

    PubMed

    Green, Oluyinka M; McKenzie, Andrew R; Shapiro, Adam B; Otterbein, Ludovic; Ni, Haihong; Patten, Arthur; Stokes, Suzanne; Albert, Robert; Kawatkar, Sameer; Breed, Jason

    2012-02-15

    A novel arylsulfonamide-containing series of compounds represented by 1, discovered by highthroughput screening, inhibit the acetyltransferase domain of N-acetylglucosamine-1-phosphate-uridyltransferase/glucosamine-1-phosphate-acetyltransferase (GlmU). X-ray structure determination confirmed that inhibitor binds at the site occupied by acetyl-CoA, indicating that series is competitive with this substrate. This letter documents our early hit-to-lead evaluation of the chemical series and some of the findings that led to improvement in in-vitro potency against Gram-negative and Gram-positive bacterial isozymes, exemplified by compound 40.

  18. Sphingosine-1-phosphate inhibits PDGF-induced chemotaxis of human arterial smooth muscle cells: spatial and temporal modulation of PDGF chemotactic signal transduction

    PubMed Central

    1995-01-01

    Activation of the PDGF receptor on human arterial smooth muscle cells (SMC) induces migration and proliferation via separable signal transduction pathways. Sphingosine-1-phosphate (Sph-1-P) can be formed following PDGF receptor activation and therefore may be implicated in PDGF-receptor signal transduction. Here we show that Sph-1-P does not significantly affect PDGF-induced DNA synthesis, proliferation, or activation of mitogenic signal transduction pathways, such as the mitogen-activated protein (MAP) kinase cascade and PI 3-kinase, in human arterial SMC. On the other hand, Sph-1-P strongly mimics PDGF receptor-induced chemotactic signal transduction favoring actin filament disassembly. Although Sph-1-P mimics PDGF, exogenously added Sph-1-P induces more prolonged and quantitatively greater PIP2 hydrolysis compared to PDGF-BB, a markedly stronger calcium mobilization and a subsequent increase in cyclic AMP levels and activation of cAMP-dependent protein kinase. This excessive and prolonged signaling favors actin filament disassembly by Sph-1-P, and results in inhibition of actin nucleation, actin filament assembly and formation of focal adhesion sites. Sph-1-P-induced interference with the dynamics of PDGF-stimulated actin filament disassembly and assembly results in a marked inhibition of cell spreading, of extension of the leading lamellae toward PDGF, and of chemotaxis toward PDGF. The results suggest that spatial and temporal changes in phosphatidylinositol turnover, calcium mobilization and actin filament disassembly may be critical to PDGF-induced chemotaxis and suggest a possible role for endogenous Sph-1-P in the regulation of PDGF receptor chemotactic signal transduction. PMID:7790372

  19. Quantification of Galactose-1-Phosphate Uridyltransferase Enzyme Activity by Liquid Chromatography–Tandem Mass Spectrometry

    PubMed Central

    Li, Yijun; Ptolemy, Adam S.; Harmonay, Lauren; Kellogg, Mark; Berry, Gerard T.

    2013-01-01

    Background The diagnosis of galactosemia usually involves the measurement of galactose-1-phosphate uridyltransferase (GALT) activity. Traditional radioactive and fluorescent GALT assays are nonspecific, laborious, and/or lack sufficient analytical sensitivity. We developed a liquid chromatography–tandem mass spectrometry (LC-MS/MS)–based assay for GALT enzyme activity measurement. Method Our assay used stable isotope-labeled α-galactose-1-phosphate ([13C6]-Gal-1-P) as an enzyme substrate. Sample cleanup and separation were achieved by reversed-phase ion-pair chromatography, and the enzymatic product, isotope-labeled uridine diphosphate galactose ([13C6]-UDPGal), was detected by MS/MS at mass transition (571 > 323) and quantified by use of [13C6]-Glu-1-P (265 > 79) as an internal standard. Results The method yielded a mean (SD) GALT enzyme activity of 23.8 (3.8) µmol · (gHgb)−1 · h−1 in erythrocyte extracts from 71 controls. The limit of quantification was 0.04 µmol · (g Hgb)−1 · h−1 (0.2% of normal control value). Intraassay imprecision was determined at 4 different levels (100%, 25%, 5%, and 0.2% of the normal control values), and the CVs were calculated to be 2.1%, 2.5%, 4.6%, and 9.7%, respectively (n = 3). Interassay imprecision CVs were 4.5%, 6.7%, 8.2%, and 13.2% (n = 5), respectively. The assay recoveries at the 4 levels were higher than 90%. The apparent Km of the 2 substrates, Gal-1-P and UDPGlc, were determined to be 0.38 mmol/L and 0.071 mmol/L, respectively. The assay in erythrocytes of 33 patients with classical galactosemia revealed no detectable activity. Conclusions This LC-MS/MS–based assay for GALT enzyme activity will be useful for the diagnosis and study of biochemically heterogeneous patients with galactosemia, especially those with uncommon genotypes and detectable but low residual activities. PMID:20348403

  20. Modification of the 1-Phosphate Group during Biosynthesis of Capnocytophaga canimorsus Lipid A.

    PubMed

    Renzi, Francesco; Zähringer, Ulrich; Chandler, Courtney E; Ernst, Robert K; Cornelis, Guy R; Ittig, Simon J

    2015-12-07

    Capnocytophaga canimorsus, a commensal bacterium of dog's mouth flora causing severe infections in humans after dog bites or scratches, has a lipopolysaccharide (LPS) (endotoxin) with low-inflammatory lipid A. In particular, it contains a phosphoethanolamine (P-Etn) instead of a free phosphate group at the C-1 position of the lipid A backbone, usually present in highly toxic enterobacterial Gram-negative lipid A. Here we show that the C. canimorsus genome comprises a single operon encoding a lipid A 1-phosphatase (LpxE) and a lipid A 1 P-Etn transferase (EptA). This suggests that lipid A is modified during biosynthesis after completing acylation of the backbone by removal of the 1-phosphate and subsequent addition of an P-Etn group. As endotoxicity of lipid A is known to depend largely on the degree of unsubstituted or unmodified phosphate residues, deletion of lpxE or eptA led to mutants lacking the P-Etn group, with consequently increased endotoxicity and decreased resistance to cationic antimicrobial peptides (CAMP). Consistent with the proposed sequential biosynthetic mechanism, the endotoxicity and CAMP resistance of a double deletion mutant of lpxE-eptA was similar to that of a single lpxE mutant. Finally, the proposed enzymatic activities of LpxE and EptA based on sequence similarity could be successfully validated by mass spectrometry (MS)-based analysis of lipid A isolated from the corresponding deletion mutant strains.

  1. Modification of the 1-Phosphate Group during Biosynthesis of Capnocytophaga canimorsus Lipid A

    PubMed Central

    Renzi, Francesco; Zähringer, Ulrich; Chandler, Courtney E.; Ernst, Robert K.; Cornelis, Guy R.

    2015-01-01

    Capnocytophaga canimorsus, a commensal bacterium of dog's mouth flora causing severe infections in humans after dog bites or scratches, has a lipopolysaccharide (LPS) (endotoxin) with low-inflammatory lipid A. In particular, it contains a phosphoethanolamine (P-Etn) instead of a free phosphate group at the C-1 position of the lipid A backbone, usually present in highly toxic enterobacterial Gram-negative lipid A. Here we show that the C. canimorsus genome comprises a single operon encoding a lipid A 1-phosphatase (LpxE) and a lipid A 1 P-Etn transferase (EptA). This suggests that lipid A is modified during biosynthesis after completing acylation of the backbone by removal of the 1-phosphate and subsequent addition of an P-Etn group. As endotoxicity of lipid A is known to depend largely on the degree of unsubstituted or unmodified phosphate residues, deletion of lpxE or eptA led to mutants lacking the P-Etn group, with consequently increased endotoxicity and decreased resistance to cationic antimicrobial peptides (CAMP). Consistent with the proposed sequential biosynthetic mechanism, the endotoxicity and CAMP resistance of a double deletion mutant of lpxE-eptA was similar to that of a single lpxE mutant. Finally, the proposed enzymatic activities of LpxE and EptA based on sequence similarity could be successfully validated by mass spectrometry (MS)-based analysis of lipid A isolated from the corresponding deletion mutant strains. PMID:26644381

  2. Rational nanoconjugation improves biocatalytic performance of enzymes: aldol addition catalyzed by immobilized rhamnulose-1-phosphate aldolase.

    PubMed

    Ardao, Inés; Comenge, Joan; Benaiges, M Dolors; Álvaro, Gregorio; Puntes, Víctor F

    2012-04-17

    Gold nanoparticles (AuNPs) are attractive materials for the immobilization of enzymes due to several advantages such as high enzyme loading, absence of internal diffusion limitations, and Brownian motion in solution, compared to the conventional immobilization onto porous macroscopic supports. The affinity of AuNPs to different groups present at the protein surface enables direct enzyme binding to the nanoparticle without the need of any coupling agent. Enzyme activity and stability appear to be improved when the biocatalyst is immobilized onto AuNPs. Rhamnulose-1-phosphate aldolase (RhuA) was selected as model enzyme for the immobilization onto AuNPs. The enzyme loading was characterized by four different techniques: surface plasmon resonance (SPR) shift and intensity, dynamic light scattering (DLS), and transmission electron microscopy (TEM). AuNPs-RhuA complexes were further applied as biocatalyst of the aldol addition reaction between dihydroxyacetone phosphate (DHAP) and (S)-Cbz-alaninal during two reaction cycles. In these conditions, an improved reaction yield and selectivity, together with a fourfold activity enhancement were observed, as compared to soluble RhuA. PMID:22428999

  3. Structure and Evolution of the Archaeal Lipid Synthesis Enzyme sn-Glycerol-1-phosphate Dehydrogenase*

    PubMed Central

    Carbone, Vincenzo; Schofield, Linley R.; Zhang, Yanli; Sang, Carrie; Dey, Debjit; Hannus, Ingegerd M.; Martin, William F.; Sutherland-Smith, Andrew J.; Ronimus, Ron S.

    2015-01-01

    One of the most critical events in the origins of cellular life was the development of lipid membranes. Archaea use isoprenoid chains linked via ether bonds to sn-glycerol 1-phosphate (G1P), whereas bacteria and eukaryotes use fatty acids attached via ester bonds to enantiomeric sn-glycerol 3-phosphate. NAD(P)H-dependent G1P dehydrogenase (G1PDH) forms G1P and has been proposed to have played a crucial role in the speciation of the Archaea. We present here, to our knowledge, the first structures of archaeal G1PDH from the hyperthermophilic methanogen Methanocaldococcus jannaschii with bound substrate dihydroxyacetone phosphate, product G1P, NADPH, and Zn2+ cofactor. We also biochemically characterized the enzyme with respect to pH optimum, cation specificity, and kinetic parameters for dihydroxyacetone phosphate and NAD(P)H. The structures provide key evidence for the reaction mechanism in the stereospecific addition for the NAD(P)H-based pro-R hydrogen transfer and the coordination of the Zn2+ cofactor during catalysis. Structure-based phylogenetic analyses also provide insight into the origins of G1PDH. PMID:26175150

  4. Antenna domain mobility and enzymatic reaction of L-rhamnulose-1-phosphate aldolase.

    PubMed

    Grueninger, Dirk; Schulz, Georg E

    2008-01-15

    The enzyme l-rhamnulose-1-phosphate aldolase from Escherichia coli participates in the degradation pathway of l-rhamnose, a ubiquitous deoxy-hexose. It is a homotetramer of the rare C4-symmetric type with N-terminal domains protruding like antennas from the main body. A mobility analysis of the enzyme gave rise to the hypothesis that an anisotropic thermal antenna motion may support the catalysis (Kroemer et al., Biochemistry 42, 10560, 2003). We checked this hypothesis by generating four single mutants and one disulfide bridge that were designed to reduce the mobility of the antenna domain without disturbing the chain-fold or the active center. The catalytic rates of the mutants revealed activity reductions that correlated well with the expected antenna fixation. Among these mutants, K15W was crystallized, structurally elucidated, and used as a guide for modeling the others. The structure confirmed the design because the mutation introduced a tight nonpolar contact to a neighboring subunit that fixed the antenna but did not affect the main chain. The fixation was confirmed by a comparison of the anisotropic B-factors describing the mobility of the domains. It turned out that the distinctly anisotropic mobility of the wild-type antenna domain has become isotropic in K15W, in agreement with the design. We suggest that, like K15W, the other mutations also followed the design, validating the correlation between antenna mobility and activity. This correlation suggests that the domain mobility facilitates the reaction.

  5. Novel effects of FTY720 on perinuclear reorganization of keratin network induced by sphingosylphosphorylcholine: Involvement of protein phosphatase 2A and G-protein-coupled receptor-12.

    PubMed

    Park, Mi Kyung; Park, Soyeun; Kim, Hyun Ji; Kim, Eun Ji; Kim, So Yeon; Kang, Gyeoung Jin; Byun, Hyun Jung; Kim, Sang Hee; Lee, Ho; Lee, Chang Hoon

    2016-03-15

    Sphingosylphosphorylcholine (SPC) evokes perinuclear reorganization of keratin 8 (K8) filaments and regulates the viscoelasticity of metastatic cancer cells leading to enhanced migration. Few studies have addressed the compounds modulating the viscoelasticity of metastatic cancer cells. We studied the effects of sphingosine (SPH), sphingosine 1-phosphate (S1P), FTY720 and FTY720-phosphate (FTY720P) on SPC-induced K8 phosphorylation and reorganization using Western blot and confocal microscopy, and also evaluated the elasticity of PANC-1 cells by atomic force microscopy. FTY720, FTY720P, SPH, and S1P concentration-dependently inhibited SPC-evoked phosphorylation and reorganization of K8, and migration of PANC-1 cells. SPC triggered reduction and narrow distribution of elastic constant K and conversely, FTY720 blocked them. A common upstream regulator of JNK and ERK, protein phosphatase 2A (PP2A) expression was reduced by SPC, but was restored by FTY720 and FTY72P. Butyryl forskolin, a PP2A activator, suppressed SPC-induced K8 phosphorylation and okadaic acid, a PP2A inhibitor, induced K8 phosphorylation. Gene silencing of PP2A also led to K8 phosphorylation, reorganization and migration. We also investigated the involvement of GPR12, a high-affinity SPC receptor, in SPC-evoked keratin phosphorylation and reorganization. GPR12 siRNA suppressed the SPC-triggered phosphorylation and reorganization of K8. GPR12 overexpression stimulated keratin phosphorylation and reorganization even without SPC. FTY720 and FTY720P suppressed the GPR12-induced phosphorylation and reorganization of K8. The collective data indicates that FTY720 and FTY720P suppress SPC-induced phosphorylation and reorganization of K8 in PANC-1 cells by restoring the expression of PP2A via GPR12. These findings might be helpful in the development of compounds that modulate the viscoelasticity of metastatic cancer cells and various SPC actions. PMID:26872988

  6. Sphingosine and FTY720 are potent inhibitors of the transient receptor potential melastatin 7 (TRPM7) channels

    PubMed Central

    Qin, Xin; Yue, Zhichao; Sun, Baonan; Yang, Wenzhong; Xie, Jia; Ni, Eric; Feng, Yi; Mahmood, Rafat; Zhang, Yanhui; Yue, Lixia

    2013-01-01

    Background and Purpose Transient receptor potential melastatin 7 (TRPM7) is a unique channel kinase which is crucial for various physiological functions. However, the mechanism by which TRPM7 is gated and modulated is not fully understood. To better understand how modulation of TRPM7 may impact biological processes, we investigated if TRPM7 can be regulated by the phospholipids sphingosine (SPH) and sphingosine-1-phosphate (S1P), two potent bioactive sphingolipids that mediate a variety of physiological functions. Moreover, we also tested the effects of the structural analogues of SPH, N,N-dimethyl-D-erythro-sphingosine (DMS), ceramides and FTY720 on TRPM7. Experimental Approach HEK293 cells stably expressing TRPM7 were used for whole-cell, single-channel and macropatch current recordings. Cardiac fibroblasts were used for native TRPM7 current recording. Key Results SPH potently inhibited TRPM7 in a concentration-dependent manner, whereas S1P and other ceramides did not produce noticeable effects. DMS also markedly inhibited TRPM7. Moreover, FTY720, an immunosuppressant and the first oral drug for treatment of multiple sclerosis, inhibited TRPM7 with a similar potency to that of SPH. In contrast, FTY720-P has no effect on TRPM7. It appears that SPH and FTY720 inhibit TRPM7 by reducing channel open probability. Furthermore, endogenous TRPM7 in cardiac fibroblasts was markedly inhibited by SPH, DMS and FTY720. Conclusions and Implications This is the first study demonstrating that SPH and FTY720 are potent inhibitors of TRPM7. Our results not only provide a new modulation mechanism of TRPM7, but also suggest that TRPM7 may serve as a direct target of SPH and FTY720, thereby mediating S1P-independent physiological/pathological functions of SPH and FTY720. Linked Article This article is commented on by Rohacs, pp. 1291–1293 of this issue. To view this commentary visit http://dx.doi.org/10.1111/bph.12070 PMID:23145923

  7. Membrane Organization and Ionization Behavior of the Minor but Crucial Lipid Ceramide-1-Phosphate

    SciTech Connect

    Kooijman, Edgar E.; Sot, Jesus; Montes, L.-Ruth; Alonso, Alicia; Gericke, Arne; de Kruijff, Ben; Kumar, Satyendra; Goni, Felix M.

    2008-08-06

    Ceramide-1-phosphate (Cer-1-P), one of the simplest of all sphingophospholipids, occurs in minor amounts in biological membranes. Yet recent evidence suggests important roles of this lipid as a novel second messenger with crucial tasks in cell survival and inflammatory responses. We present a detailed description of the physical chemistry of this hitherto little explored membrane lipid. At full hydration Cer-1-P forms a highly organized subgel (crystalline) bilayer phase (L{sub c}) at low temperature, which transforms into a regular gel phase (L{sub {beta}}) at {approx}45 C, with the gel to fluid phase transition (L{sub {beta}}-L{sub {alpha}}) occurring at {approx}65 C. When incorporated at 5mol % in a phosphatidylcholine bilayer, the pK{sub a2} of Cer-1-P, 7.39{+-}0.03, lies within the physiological pH range. Inclusion of phosphatidylethanolamine in the phosphatidylcholine bilayer, at equimolar ratio, dramatically reduces the pK{sub a2} to 6.64{+-}0.03. We explain these results in light of the novel electrostatic/hydrogen bond switch model described recently for phosphatidic acid. In mixtures with dielaidoylphosphatidylethanolamine, small concentrations of Cer-1-P cause a large reduction of the lamellar-to-inverted hexagonal phase transition temperature, suggesting that Cer-1-P induces, like phosphatidic acid, negative membrane curvature in these types of lipid mixtures. These properties place Cer-1-P in a class more akin to certain glycerophospholipids (phosphatidylethanolamine, phosphatidic acid) than to any other sphingolipid. In particular, the similarities and differences between ceramide and Cer-1-P may be relevant in explaining some of their physiological roles.

  8. Glucose-1-phosphate transport into protoplasts and chloroplasts from leaves of Arabidopsis.

    PubMed

    Fettke, Joerg; Malinova, Irina; Albrecht, Tanja; Hejazi, Mahdi; Steup, Martin

    2011-04-01

    Almost all glucosyl transfer reactions rely on glucose-1-phosphate (Glc-1-P) that either immediately acts as glucosyl donor or as substrate for the synthesis of the more widely used Glc dinucleotides, ADPglucose or UDPglucose. In this communication, we have analyzed two Glc-1-P-related processes: the carbon flux from externally supplied Glc-1-P to starch by either mesophyll protoplasts or intact chloroplasts from Arabidopsis (Arabidopsis thaliana). When intact protoplasts or chloroplasts are incubated with [U-(14)C]Glc-1-P, starch is rapidly labeled. Incorporation into starch is unaffected by the addition of unlabeled Glc-6-P or Glc, indicating a selective flux from Glc-1-P to starch. However, illuminated protoplasts incorporate less (14)C into starch when unlabeled bicarbonate is supplied in addition to the (14)C-labeled Glc-1-P. Mesophyll protoplasts incubated with [U-(14)C]Glc-1-P incorporate (14)C into the plastidial pool of adenosine diphosphoglucose. Protoplasts prepared from leaves of mutants of Arabidopsis that lack either the plastidial phosphorylase or the phosphoglucomutase isozyme incorporate (14)C derived from external Glc-1-P into starch, but incorporation into starch is insignificant when protoplasts from a mutant possessing a highly reduced ADPglucose pyrophosphorylase activity are studied. Thus, the path of assimilatory starch biosynthesis initiated by extraplastidial Glc-1-P leads to the plastidial pool of adenosine diphosphoglucose, and at this intermediate it is fused with the Calvin cycle-driven route. Mutants lacking the plastidial phosphoglucomutase contain a small yet significant amount of transitory starch.

  9. Subfertility and growth restriction in a new galactose-1 phosphate uridylyltransferase (GALT) - deficient mouse model

    PubMed Central

    Tang, Manshu; Siddiqi, Anwer; Witt, Benjamin; Yuzyuk, Tatiana; Johnson, Britt; Fraser, Nisa; Chen, Wyman; Rascon, Rafael; Yin, Xue; Goli, Harish; Bodamer, Olaf A; Lai, Kent

    2014-01-01

    The first GalT gene knockout (KO) mouse model for Classic Galactosemia (OMIM 230400) accumulated some galactose and its metabolites upon galactose challenge, but was seemingly fertile and symptom free. Here we constructed a new GalT gene-trapped mouse model by injecting GalT gene-trapped mouse embryonic stem cells into blastocysts, which were later implanted into pseudo-pregnant females. High percentage GalT gene-trapped chimera obtained were used to generate heterozygous and subsequently, homozygous GalT gene-trapped mice. Biochemical assays confirmed total absence of galactose-1 phosphate uridylyltransferase (GALT) activity in the homozygotes. Although the homozygous GalT gene-trapped females could conceive and give birth when fed with normal chow, they had smaller litter size (P=0.02) and longer time-to-pregnancy (P=0.013) than their wild-type littermates. Follicle-stimulating hormone levels of the mutant female mice were not significantly different from the age-matched, wild-type females, but histological examination of the ovaries revealed fewer follicles in the homozygous mutants (P=0.007). Administration of a high-galactose (40% w/w) diet to lactating homozygous GalT gene-trapped females led to lethality in over 70% of the homozygous GalT gene-trapped pups before weaning. Cerebral edema, abnormal changes in the Purkinje and the outer granular cell layers of the cerebellum, as well as lower blood GSH/GSSG ratio were identified in the galactose-intoxicated pups. Finally, reduced growth was observed in GalT gene-trapped pups fed with normal chow and all pups fed with high-galactose (20% w/w) diet. This new mouse model presents several of the complications of Classic Galactosemia and will be useful to investigate pathogenesis and new therapies. PMID:24549051

  10. Fructose 1-Phosphate Is the Preferred Effector of the Metabolic Regulator Cra of Pseudomonas putida*

    PubMed Central

    Chavarría, Max; Santiago, César; Platero, Raúl; Krell, Tino; Casasnovas, José M.; de Lorenzo, Víctor

    2011-01-01

    The catabolite repressor/activator (Cra) protein is a global sensor and regulator of carbon fluxes through the central metabolic pathways of Gram-negative bacteria. To examine the nature of the effector (or effectors) that signal such fluxes to the protein of Pseudomonas putida, the Cra factor of this soil microorganism has been purified and characterized and its three-dimensional structure determined. Analytical ultracentrifugation, gel filtration, and mobility shift assays showed that the effector-free Cra is a dimer that binds an operator DNA sequence in the promoter region of the fruBKA cluster. Furthermore, fructose 1-phosphate (F1P) was found to most efficiently dissociate the Cra-DNA complex. Thermodynamic parameters of the F1P-Cra-DNA interaction calculated by isothermal titration calorimetry revealed that the factor associates tightly to the DNA sequence 5′-TTAAACGTTTCA-3′ (KD = 26.3 ± 3.1 nm) and that F1P binds the protein with an apparent stoichiometry of 1.06 ± 0.06 molecules per Cra monomer and a KD of 209 ± 20 nm. Other possible effectors, like fructose 1,6-bisphosphate, did not display a significant affinity for the regulator under the assay conditions. Moreover, the structure of Cra and its co-crystal with F1P at a 2-Å resolution revealed that F1P fits optimally the geometry of the effector pocket. Our results thus single out F1P as the preferred metabolic effector of the Cra protein of P. putida. PMID:21239488

  11. Glucose-1-Phosphate Transport into Protoplasts and Chloroplasts from Leaves of Arabidopsis1

    PubMed Central

    Fettke, Joerg; Malinova, Irina; Albrecht, Tanja; Hejazi, Mahdi; Steup, Martin

    2011-01-01

    Almost all glucosyl transfer reactions rely on glucose-1-phosphate (Glc-1-P) that either immediately acts as glucosyl donor or as substrate for the synthesis of the more widely used Glc dinucleotides, ADPglucose or UDPglucose. In this communication, we have analyzed two Glc-1-P-related processes: the carbon flux from externally supplied Glc-1-P to starch by either mesophyll protoplasts or intact chloroplasts from Arabidopsis (Arabidopsis thaliana). When intact protoplasts or chloroplasts are incubated with [U-14C]Glc-1-P, starch is rapidly labeled. Incorporation into starch is unaffected by the addition of unlabeled Glc-6-P or Glc, indicating a selective flux from Glc-1-P to starch. However, illuminated protoplasts incorporate less 14C into starch when unlabeled bicarbonate is supplied in addition to the 14C-labeled Glc-1-P. Mesophyll protoplasts incubated with [U-14C]Glc-1-P incorporate 14C into the plastidial pool of adenosine diphosphoglucose. Protoplasts prepared from leaves of mutants of Arabidopsis that lack either the plastidial phosphorylase or the phosphoglucomutase isozyme incorporate 14C derived from external Glc-1-P into starch, but incorporation into starch is insignificant when protoplasts from a mutant possessing a highly reduced ADPglucose pyrophosphorylase activity are studied. Thus, the path of assimilatory starch biosynthesis initiated by extraplastidial Glc-1-P leads to the plastidial pool of adenosine diphosphoglucose, and at this intermediate it is fused with the Calvin cycle-driven route. Mutants lacking the plastidial phosphoglucomutase contain a small yet significant amount of transitory starch. PMID:21115809

  12. Origins, distribution and expression of the Duarte-2 (D2) allele of galactose-1-phosphate uridylyltransferase

    PubMed Central

    Carney, Amanda E.; Sanders, Rebecca D.; Garza, Kerry R.; McGaha, Lee Anne; Bean, Lora J. H.; Coffee, Bradford W.; Thomas, James W.; Cutler, David J.; Kurtkaya, Natalie L.; Fridovich-Keil, Judith L.

    2009-01-01

    Duarte galactosemia is a mild to asymptomatic condition that results from partial impairment of galactose-1-phosphate uridylyltransferase (GALT). Patients with Duarte galactosemia demonstrate reduced GALT activity and carry one profoundly impaired GALT allele (G) along with a second, partially impaired GALT allele (Duarte-2, D2). Molecular studies reveal at least five sequence changes on D2 alleles: a p.N314D missense substitution, three intronic base changes and a 4 bp deletion in the 5′ proximal sequence. The four non-coding sequence changes are unique to D2. The p.N314D substitution, however, is not; it is found together with a silent polymorphism, p.L218(TTA), on functionally normal Duarte-1 alleles (D1, also called Los Angeles or LA alleles). The HapMap database reveals that p.N314D is a common human variant, and cross-species comparisons implicate D314 as the ancestral allele. The p.N314D substitution is also functionally neutral in mammalian cell and yeast expression studies. In contrast, the 4 bp 5′ deletion characteristic of D2 alleles appears to be functionally impaired in reporter gene transfection studies. Here we present allele-specific qRT–PCR evidence that D2 alleles express less mRNA in vivo than their wild-type counterparts; the difference is small but statistically significant. Furthermore, we characterize the prevalence of the 4 bp deletion in GG, NN and DG populations; the deletion appears exclusive to D2 alleles. Combined, these data strongly implicate the 4 bp 5′ deletion as a causal mutation in Duarte galactosemia and suggest that direct tests for this deletion, as proposed here, could enhance or supplant current tests, which define D2 alleles on the basis of the presence and absence of linked coding sequence polymorphisms. PMID:19224951

  13. CERAMIDE AND SPHINGOSINE-1-PHOSPHATE ACT AS PHOTODYNAMIC THERAPY-ELICITED DAMAGE-ASSOCIATED MOLECULAR PATTERNS: CELL SURFACE EXPOSURE

    PubMed Central

    Korbelik, Mladen; Banáth, Judit; Sun, Jinghai; Canals, Daniel; Hannun, Yusuf A.; Separovic, Duska

    2014-01-01

    Molecules that appear on the surface of tumor cells after their therapy treatment may have important roles either as damage-associated molecular patterns (DAMPs) or signals for phagocytes influencing the disposal of these cells. Treatment of SCCVII and CAL27 cells, models of mouse and human squamous cell carcinoma respectively, by photodynamic therapy (PDT) resulted in the presentation of ceramide and sphingosine-1-phposphate (S1P) on the cell surface. This was documented by anti-ceramide and anti-S1P antibody staining followed by flow cytometry. The exposure of these key sphingolipid molecules on PDT-treated tumor cells was PDT dose-dependent and it varied in intensity with different photosensitizers used for PDT. The above results, together with the finding that both ceramide and S1P can activate NFκB signaling in macrophages co-incubated with PDT-treated tumor cells, establish that these two sphingolipids can act as DAMPs stimulating inflammatory/immune reactions critical for tumor therapy response. PMID:24713544

  14. Synthesis and Physicochemical Characterization of D-Tagatose-1-phosphate: The Substrate of the Tagatose-1-Phosphate Kinase TagK in the PTS-mediated D-Tagatose Catabolic Pathway of Bacillus licheniformis

    PubMed Central

    Van der Heiden, Edwige; Delmarcelle, Michaël; Simon, Patricia; Counson, Melody; Galleni, Moreno; Freedberg, Darón I.; Thompson, John; Joris, Bernard; Battistel, Marcos D.

    2015-01-01

    We report the first enzymatic synthesis of D-tagatose-1-phosphate (Tag-1P) by the multi-component PEP-dependent:tag-PTS present in tagatose-grown cells of Klebsiella pneumoniae. Physicochemical characterization by 31P and 1H NMR spectroscopy reveals that, in solution, this derivative is primarily in the pyranose form. Tag-1P was used to characterize the putative tagatose-1-phosphate kinase (TagK) of the Bacillus licheniformis PTS-mediated D-Tagatose catabolic Pathway (Bli-TagP). For this purpose, a soluble protein fusion was obtained with the 6 His-tagged trigger factor (TFHis6) of Escherichia coli. The active fusion enzyme was named TagK-TFHis6. Tag-1P and D-fructose-1-phosphate (Fru-1P) are substrates for the TagK-TFHis6 enzyme, whereas the isomeric derivatives D-tagatose-6-phosphate (Tag-6P) and D-fructose-6-phosphate (Fru-6P) are inhibitors. Studies of catalytic efficiency (kcat/Km) reveal that the enzyme specificity is markedly in favor of Tag-1P as substrate. Importantly, we show in vivo that the transfer of the phosphate moiety from PEP to the B. licheniformis tagatose-specific enzyme II (EIITag) in E.coli is inefficient. The capability of the PTS general cytoplasmic components of B. subtilis, HPr and EI, to restore the phosphate transfer is demonstrated. PMID:26159072

  15. Genetics of the ceramide/sphingosine-1-phosphate rheostat in blood pressure regulation and hypertension

    PubMed Central

    2011-01-01

    network using the epistatic values revealed that only 17% of the interactions detected were in the direct metabolic pathway, the remaining jumping one or more intermediates. Conclusions This study established the components of the ceramide/sphingosine-1-phosphate rheostat as central to blood pressure regulation. The results in addition confirm that epistasis is of paramount importance and is most conspicuous in the regulation of the rheostat network. Finally, it is shown that applying a simple case-control approach with single gene association analysis is bound to fail, short of identifying a few potential genes with small effects. PMID:21569466

  16. Glucose 1-phosphate is efficiently taken up by potato (Solanum tuberosum) tuber parenchyma cells and converted to reserve starch granules.

    PubMed

    Fettke, Joerg; Albrecht, Tanja; Hejazi, Mahdi; Mahlow, Sebastian; Nakamura, Yasunori; Steup, Martin

    2010-02-01

    Reserve starch is an important plant product but the actual biosynthetic process is not yet fully understood. Potato (Solanum tuberosum) tuber discs from various transgenic plants were used to analyse the conversion of external sugars or sugar derivatives to starch. By using in vitro assays, a direct glucosyl transfer from glucose 1-phosphate to native starch granules as mediated by recombinant plastidial phosphorylase was analysed. Compared with labelled glucose, glucose 6-phosphate or sucrose, tuber discs converted externally supplied [(14)C]glucose 1-phosphate into starch at a much higher rate. Likewise, tuber discs from transgenic lines with a strongly reduced expression of cytosolic phosphoglucomutase, phosphorylase or transglucosidase converted glucose 1-phosphate to starch with the same or even an increased rate compared with the wild-type. Similar results were obtained with transgenic potato lines possessing a strongly reduced activity of both the cytosolic and the plastidial phosphoglucomutase. Starch labelling was, however, significantly diminished in transgenic lines, with a reduced concentration of the plastidial phosphorylase isozymes. Two distinct paths of reserve starch biosynthesis are proposed that explain, at a biochemical level, the phenotype of several transgenic plant lines.

  17. Enzymatic synthesis of rare sugars with L-rhamnulose-1-phosphate aldolase from Thermotoga maritima MSB8.

    PubMed

    Li, Zijie; Wu, Xiaoru; Cai, Li; Duan, Shenglin; Liu, Jia; Yuan, Peng; Nakanishi, Hideki; Gao, Xiao-Dong

    2015-09-15

    L-Rhamnulose-1-phosphate aldolase from a thermophilic source (Thermotoga maritima MSB8) (RhaDT.mari) was heterologously overexpressed in Escherichia coli and the stereoselectivity of this enzyme with or without Nus tag was investigated. We also applied this enzyme to the synthesis of rare sugars D-psicose, D-sorbose, L-tagatose and L-fructose using our one-pot four-enzyme system. To the best of our knowledge, this is the first use of RhaD from a thermophilic source for rare sugar synthesis and the temperature tolerance of this enzyme paves the path for large scale fermentation.

  18. Identification of a sphingolipid-specific phospholipase D activity associated with the generation of phytoceramide-1-phosphate in cabbage leaves.

    PubMed

    Tanaka, Tamotsu; Kida, Takashi; Imai, Hiroyuki; Morishige, Jun-ichi; Yamashita, Ryouhei; Matsuoka, Hisatsugu; Uozumi, Sachika; Satouchi, Kiyoshi; Nagano, Minoru; Tokumura, Akira

    2013-08-01

    The structure and biosynthetic route for an unidentified lipid (lipid X) detected by TLC of cabbage (Brassica oleracea) lipids was determined. Lipid X is a phospholipid that is resistant to mild alkali and detectable by MALDI-TOF MS as an adduct with Phos-tag, a phosphate-capture zinc complex. Various α-hydroxy fatty acids (16:0, 22:0, 24:0 and 24:1) were detected by GC-MS of fatty acid methyl esters prepared from lipid X. The deacyl derivative of lipid X was determined to be 4-hydroxysphingenine (dehydrophytosphingosine)-1-phosphate by MALDI-TOF MS with Phos-tag. From these results, lipid X was determined to be phytoceramide-1-phosphate (PC1P) with an α-hydroxy fatty acid. When cabbage homogenates were incubated, PC1P was formed, with a concomitant decrease in the amount of glycosylinositol phosphoceramide (GIPC). The formation of PC1P from GIPC was confirmed by treatment of purified cabbage GIPC with a membrane fraction of cabbage homogenates. Using a partially purified enzyme fraction, we found that the enzyme hydrolyzes GIPC specifically, but not glycerophospholipids and sphingomyelin. Arabidopsis thaliana also had this enzyme activity. From these results, we conclude that a previously uncharacterized phospholipase D activity that specifically hydrolyzes GIPC produces PC1P in brassicaceous plants. PMID:23738625

  19. β-Glucose-1-Phosphate, a Possible Mediator for Polysaccharide Formation in Maltose-Assimilating Lactococcus lactis

    PubMed Central

    Sjöberg, Annelie; Hahn-Hägerdal, Bärbel

    1989-01-01

    Homolactic fermentation of glucose and heterolactic fermentation of maltose with Lactococcus lactis 65.1 were confirmed. When moles of glucose were compared, the uptake rates of the two carbon sources were similar. The intracellular concentration of fructose-1,6-diphosphate (FDP) in maltose-assimilating cells was half of that in glucose-assimilating cells. Similarly, formation of FDP and lactate from maltose by extracts of maltose-grown cells was half of that formed from glucose by extracts of glucose-grown cells, indicating a difference in the utilization of the two carbon sources for energy metabolism. Concentrations of adenine nucleotides were similar in both types of cells. Glucose-1-phosphate was found in extracts of maltose-grown cells given maltose and, in addition, an inducible and low β-specific phosphoglucomutase activity was observed. β-Glucose-1-phosphate was not metabolized by cell extracts to either FDP or lactate, suggesting an alternative metabolic route. The amount of [14C]maltose incorporated into the cell material of maltose-grown cells was four times greater than that of [14C]glucose incorporated into the cell material of glucose-grown cells. The intracellular concentration of UTP was lower in maltose-assimilating cells than in glucose-assimilating cells. Cells grown on maltose were more spherical and less fragile than cells grown on glucose. Images PMID:16347948

  20. A limitation of the continuous spectrophotometric assay for the measurement of myo-inositol-1-phosphate synthase activity.

    PubMed

    Huang, Xinyi; Hernick, Marcy

    2011-10-15

    Myo-inositol-1-phosphate synthase (MIPS) catalyzes the conversion of glucose-6-phosphate to myo-inositol-1-phosphate. The reaction catalyzed by MIPS is the first step in the biosynthesis of inositol and inositol-containing molecules that serve important roles in both eukaryotes and prokaryotes. Consequently, MIPS is a target for the development of therapeutic agents for the treatment of infectious diseases and bipolar disorder. We recently reported a continuous spectrophotometric method for measuring MIPS activity using a coupled assay that allows the rapid characterization of MIPS in a multiwell plate format. Here we validate the continuous assay as a high-throughput alternative for measuring MIPS activity and report on one limitation of this assay-the inability to examine the effect of divalent metal ions (at high concentrations) on MIPS activity. In addition, we demonstrate that the activity of MIPS from Arabidopsis thaliana is moderately enhanced by the addition Mg(2+) and is not enhanced by other divalent metal ions (Zn(2+) and Mn(2+)), consistent with what has been observed for other eukaryotic MIPS enzymes. Our findings suggest that the continuous assay is better suited for characterizing eukaryotic MIPS enzymes that require monovalent cations as cofactors than for characterizing bacterial or archeal MIPS enzymes that require divalent metal ions as cofactors. PMID:21729692

  1. Studies on the inhibition of sphingosine-1-phosphate lyase by stabilized reaction intermediates and stereodefined azido phosphates.

    PubMed

    Sanllehí, Pol; Abad, José-Luís; Bujons, Jordi; Casas, Josefina; Delgado, Antonio

    2016-11-10

    Two kinds of inhibitors of the PLP-dependent enzyme sphingosine-1-phosphate lyase have been designed and tested on the bacterial (StS1PL) and the human (hS1PL) enzymes. Amino phosphates 1, 12, and 32, mimicking the intermediate aldimines of the catalytic process, were weak inhibitors on both enzyme sources. On the other hand, a series of stereodefined azido phosphates, resulting from the replacement of the amino group of the natural substrates with an azido group, afforded competitive inhibitors in the low micromolar range on both enzyme sources. This similar behavior represents an experimental evidence of the reported structural similarities for both enzymes at their active site level. Interestingly, the anti-isomers of the non-natural enantiomeric series where the most potent inhibitors on hS1PL.

  2. Expression, purification, crystallization and preliminary X-ray analysis of glucose-1-phosphate uridylyltransferase (GalU) from Erwinia amylovora

    PubMed Central

    Toccafondi, Mirco; Cianci, Michele; Benini, Stefano

    2014-01-01

    Glucose-1-phosphate uridylyltransferase from Erwinia amylovora CFPB1430 was expressed as a His-tag fusion protein in Escherichia coli. After tag removal, the purified protein was crystallized from 100 mM Tris pH 8.5, 2 M ammonium sulfate, 5% ethylene glycol. Diffraction data sets were collected to a maximum resolution of 2.46 Å using synchrotron radiation. The crystals belonged to the hexagonal space group P62, with unit-cell parameters a = 80.67, b = 80.67, c = 169.18. The structure was solved by molecular replacement using the structure of the E. coli enzyme as a search model. PMID:25195902

  3. Generation of reactive oxygen species (ROS) is a key factor for stimulation of macrophage proliferation by ceramide 1-phosphate

    SciTech Connect

    Arana, Lide; Gangoiti, Patricia; Ouro, Alberto; Rivera, Io-Guane; Ordonez, Marta; Trueba, Miguel; Lankalapalli, Ravi S.; Bittman, Robert; Gomez-Munoz, Antonio

    2012-02-15

    We previously demonstrated that ceramide 1-phosphate (C1P) is mitogenic for fibroblasts and macrophages. However, the mechanisms involved in this action were only partially described. Here, we demonstrate that C1P stimulates reactive oxygen species (ROS) formation in primary bone marrow-derived macrophages, and that ROS are required for the mitogenic effect of C1P. ROS production was dependent upon prior activation of NADPH oxidase by C1P, which was determined by measuring phosphorylation of the p40phox subunit and translocation of p47phox from the cytosol to the plasma membrane. In addition, C1P activated cytosolic calcium-dependent phospholipase A{sub 2} and protein kinase C-{alpha}, and NADPH oxidase activation was blocked by selective inhibitors of these enzymes. These inhibitors, and inhibitors of ROS production, blocked the mitogenic effect of C1P. By using BHNB-C1P (a photolabile caged-C1P analog), we demonstrate that all of these C1P actions are caused by intracellular C1P. It can be concluded that the enzyme responsible for C1P-stimulated ROS generation in bone marrow-derived macrophages is NADPH oxidase, and that this enzyme is downstream of PKC-{alpha} and cPLA{sub 2}-{alpha} in this pathway. -- Highlights: Black-Right-Pointing-Pointer Ceramide 1-phosphate (C1P) stimulates reactive oxygen species (ROS) formation. Black-Right-Pointing-Pointer The enzyme responsible for ROS generation by C1P in macrophages is NADPH oxidase. Black-Right-Pointing-Pointer NADPH oxidase lies downstream of cPLA{sub 2}-{alpha} and PKC-{alpha} in this pathway. Black-Right-Pointing-Pointer ROS generation is essential for the stimulation of macrophage proliferation by C1P.

  4. Functional characterization of UDP-glucose:undecaprenyl-phosphate glucose-1-phosphate transferases of Escherichia coli and Caulobacter crescentus.

    PubMed

    Patel, Kinnari B; Toh, Evelyn; Fernandez, Ximena B; Hanuszkiewicz, Anna; Hardy, Gail G; Brun, Yves V; Bernards, Mark A; Valvano, Miguel A

    2012-05-01

    Escherichia coli K-12 WcaJ and the Caulobacter crescentus HfsE, PssY, and PssZ enzymes are predicted to initiate the synthesis of colanic acid (CA) capsule and holdfast polysaccharide, respectively. These proteins belong to a prokaryotic family of membrane enzymes that catalyze the formation of a phosphoanhydride bond joining a hexose-1-phosphate with undecaprenyl phosphate (Und-P). In this study, in vivo complementation assays of an E. coli K-12 wcaJ mutant demonstrated that WcaJ and PssY can complement CA synthesis. Furthermore, WcaJ can restore holdfast production in C. crescentus. In vitro transferase assays demonstrated that both WcaJ and PssY utilize UDP-glucose but not UDP-galactose. However, in a strain of Salmonella enterica serovar Typhimurium deficient in the WbaP O antigen initiating galactosyltransferase, complementation with WcaJ or PssY resulted in O-antigen production. Gas chromatography-mass spectrometry (GC-MS) analysis of the lipopolysaccharide (LPS) revealed the attachment of both CA and O-antigen molecules to lipid A-core oligosaccharide (OS). Therefore, while UDP-glucose is the preferred substrate of WcaJ and PssY, these enzymes can also utilize UDP-galactose. This unexpected feature of WcaJ and PssY may help to map specific residues responsible for the nucleotide diphosphate specificity of these or similar enzymes. Also, the reconstitution of O-antigen synthesis in Salmonella, CA capsule synthesis in E. coli, and holdfast synthesis provide biological assays of high sensitivity to examine the sugar-1-phosphate transferase specificity of heterologous proteins.

  5. Ultra Fast and Sensitive Liquid Chromatography Tandem Mass Spectrometry Based Assay for Galactose-1-Phosphate Uridylyltransferase and Galactokinase Deficiencies

    PubMed Central

    Li, Yijun; Ptolemy, Adam S.; Harmonay, Lauren; Kellogg, Mark; Berry, Gerard T.

    2013-01-01

    The diagnosis of transferase and galactokinase deficiency galactosemia usually involves the measurement of erythrocyte galactose-1-phosphate uridylyltransferase (GALT) and galactokinase (GALK) enzyme activity, respectively. The current gold standard assays for these enzymes are radioactive assays, which are laborious and/or incapable of measuring low enzyme activities. To further our knowledge of genotype-phenotype relationships, we had developed an assay for GALT activity alone using LC-MS/MS. In this study we generated a robust and sensitive LC-MS/MS based GALT and GALK assay using a novel normal phase chromatographic condition. We improved upon our earlier assay by drastically reducing the instrument run time and eliminating the use of an ion pairing reagent. Stable isotope labeled substrates were utilized in the GALT and GALK assays. The enzymatic products ([13C6]-uridine diphosphate galactose in GALT assay and [13C6]-galactose-1-phosphate in GALK assay) were quantified in a 3 min LC-MS/MS run. The assays were sensitive enough to allow for the quantification of enzyme activities as low as 0.2% and 0.3% of normal control values in the GALT and GALK assays, respectively. Thirty-three samples from non-galactosemic patients were assayed to have erythrocyte GALT activity of 23.4 ± 4.2 and GALK activity of 1.8 ± 0.47 (mean ± SD) µmol·(g Hgb) −1·hr−1. Erythrocyte GALT activities in a cohort of 16 patients with classic galactosemia were measured: 4 patients had GALT activity less than 1% of normal control values and the remaining 12 had no detectable GALT activity. No GALK activity was detected in a GALK deficient sample we analzyed. Lastly, we tested the feasibility of adapting this LC-MS/MS based GALT/GALK assay as a newborn screening (NBS) test. PMID:20863731

  6. Ultra fast and sensitive liquid chromatography tandem mass spectrometry based assay for galactose-1-phosphate uridylyltransferase and galactokinase deficiencies.

    PubMed

    Li, Yijun; Ptolemy, Adam S; Harmonay, Lauren; Kellogg, Mark; Berry, Gerard T

    2011-01-01

    The diagnosis of transferase and galactokinase deficiency galactosemia usually involves the measurement of erythrocyte galactose-1-phosphate uridylyltransferase (GALT) and galactokinase (GALK) enzyme activity, respectively. The current gold standard assays for these enzymes are radioactive assays, which are laborious and/or incapable of measuring low enzyme activities. To further our knowledge of genotype-phenotype relationships, we had developed an assay for GALT activity alone using LC-MS/MS. In this study we generated a robust and sensitive LC-MS/MS based GALT and GALK assay using a novel normal phase chromatographic condition. We improved upon our earlier assay by drastically reducing the instrument run time and eliminating the use of an ion pairing reagent. Stable isotope labeled substrates were utilized in the GALT and GALK assays. The enzymatic products ([(13)C(6)]-uridine diphosphate galactose in GALT assay and [(13)C(6)]-galactose-1-phosphate in GALK assay) were quantified in a 3 min LC-MS/MS run. The assays were sensitive enough to allow for the quantification of enzyme activities as low as 0.2% and 0.3% of normal control values in the GALT and GALK assays, respectively. Thirty-three samples from non-galactosemic patients were assayed to have erythrocyte GALT activity of 23.4±4.2 and GALK activity of 1.8±0.47 (mean±SD) μmol⋅(g Hgb)(-1) h(-1). Erythrocyte GALT activities in a cohort of 16 patients with classic or severe galactosemia were measured: 4 patients had GALT activity less than 1% of normal control values and the remaining 12 had no detectable GALT activity. No GALK activity was detected in a GALK deficient sample we analyzed. Lastly, we tested the feasibility of adapting this LC-MS/MS based GALT/GALK assay as a newborn screening (NBS) test.

  7. Ultra fast and sensitive liquid chromatography tandem mass spectrometry based assay for galactose-1-phosphate uridylyltransferase and galactokinase deficiencies.

    PubMed

    Li, Yijun; Ptolemy, Adam S; Harmonay, Lauren; Kellogg, Mark; Berry, Gerard T

    2011-01-01

    The diagnosis of transferase and galactokinase deficiency galactosemia usually involves the measurement of erythrocyte galactose-1-phosphate uridylyltransferase (GALT) and galactokinase (GALK) enzyme activity, respectively. The current gold standard assays for these enzymes are radioactive assays, which are laborious and/or incapable of measuring low enzyme activities. To further our knowledge of genotype-phenotype relationships, we had developed an assay for GALT activity alone using LC-MS/MS. In this study we generated a robust and sensitive LC-MS/MS based GALT and GALK assay using a novel normal phase chromatographic condition. We improved upon our earlier assay by drastically reducing the instrument run time and eliminating the use of an ion pairing reagent. Stable isotope labeled substrates were utilized in the GALT and GALK assays. The enzymatic products ([(13)C(6)]-uridine diphosphate galactose in GALT assay and [(13)C(6)]-galactose-1-phosphate in GALK assay) were quantified in a 3 min LC-MS/MS run. The assays were sensitive enough to allow for the quantification of enzyme activities as low as 0.2% and 0.3% of normal control values in the GALT and GALK assays, respectively. Thirty-three samples from non-galactosemic patients were assayed to have erythrocyte GALT activity of 23.4±4.2 and GALK activity of 1.8±0.47 (mean±SD) μmol⋅(g Hgb)(-1) h(-1). Erythrocyte GALT activities in a cohort of 16 patients with classic or severe galactosemia were measured: 4 patients had GALT activity less than 1% of normal control values and the remaining 12 had no detectable GALT activity. No GALK activity was detected in a GALK deficient sample we analyzed. Lastly, we tested the feasibility of adapting this LC-MS/MS based GALT/GALK assay as a newborn screening (NBS) test. PMID:20863731

  8. Morin reduces hepatic inflammation-associated lipid accumulation in high fructose-fed rats via inhibiting sphingosine kinase 1/sphingosine 1-phosphate signaling pathway.

    PubMed

    Wang, Xing; Zhang, Dong-Mei; Gu, Ting-Ting; Ding, Xiao-Qin; Fan, Chen-Yu; Zhu, Qin; Shi, Yun-Wei; Hong, Ye; Kong, Ling-Dong

    2013-12-15

    SphK1/S1P signaling pathway is involved in the development of hepatic inflammation and injury. But its role in high fructose-induced NAFLD has not yet been reported. The aim of this study was to elucidate the crucial role of SphK1/S1P signaling pathway in high fructose-induced hepatic inflammation and lipid accumulation in rats. Moreover, the hepatoprotective effects of morin, a flavonoid with anti-inflammatory and anti-hyperlipedimic activities, on these hepatic changes in rats were investigated. High fructose-fed rats were orally treated with morin (30 and 60mg/kg) and pioglitazone (4mg/kg) for 8 weeks, respectively. Fructose feeding induced hyperlipidemia, and activated SphK1/S1P signaling pathway characterized by the elevation of SphK1 activity, S1P production as well as SphK1, S1PR1 and S1PR3 protein levels, which in turn caused NF-κB signaling activation to produce IL-1β, IL-6 and TNF-α and inflammation in the liver of rats. Subsequently, hepatic insulin and leptin signaling impairment and lipid metabolic disorder were observed in this animal model, resulting in liver lipid accumulation. Morin restored high fructose-induced the activation of hepatic SphK1/S1P signaling pathway in rats. Subsequently, the reduced NF-κB signaling activation by morin decreased inflammatory cytokine production, recovered insulin and leptin signaling impairment to reduce lipid accumulation and injury in the rat liver. These effects of morin were confirmed in Buffalo rat liver (BRL3A) cell model stimulated with 5mM fructose. Thus, the inhibition of hepatic SphK1/S1P signaling pathway may be a novel mechanism by which morin exerts hepatoprotection in high fructose-fed rats, possibly involving liver inflammation inhibition and lipid accumulation recovery.

  9. Post-transcriptional modification of the poly(A) length of galactose-1-phosphate uridyl transferase mRNA in Saccharomyces cerevisiae.

    PubMed Central

    Saunders, C A; Bostian, K A; Halvorson, H O

    1980-01-01

    Thermal elution poly(U)-Sepharose chromatography was utilized to fractionate yeast mRNA based on poly(A) size. Analysis of the in vitro translation products of the fractionated RNAs in a wheat-embryo cell-free protein synthesis system shows a heterogeneous but equal distribution of these abundant translatable mRNAs in the different poly(A) size classes. By comparing the translational activity of inducible galactose-1-phosphate uridyl transferase mRNA, which can be monitored as a function of age, to contitutive mRNAs, we demonstrate that initially galactose-1-phosphate uridyl transferase mRNA has a uniformly large poly(A) tail which becomes heterogeneous and shorter with age in the cytoplasm. These observations are consistent with the previously observed cytoplasmic poly(A) catabolism in yeast and with cytoplasmic post-transcriptional modification of the poly(A) length of galactose-1-phosphate uridyl transferase mRNA. Images PMID:6255420

  10. Mechanistic characterization of the tetraacyldisaccharide-1-phosphate 4'-kinase LpxK involved in lipid A biosynthesis.

    PubMed

    Emptage, Ryan P; Pemble, Charles W; York, John D; Raetz, Christian R H; Zhou, Pei

    2013-04-01

    The sixth step in the lipid A biosynthetic pathway involves phosphorylation of the tetraacyldisaccharide-1-phosphate (DSMP) intermediate by the cytosol-facing inner membrane kinase LpxK, a member of the P-loop-containing nucleoside triphosphate (NTP) hydrolase superfamily. We report the kinetic characterization of LpxK from Aquifex aeolicus and the crystal structures of LpxK in complex with ATP in a precatalytic binding state, the ATP analogue AMP-PCP in the closed catalytically competent conformation, and a chloride anion revealing an inhibitory conformation of the nucleotide-binding P-loop. We demonstrate that LpxK activity in vitro requires the presence of a detergent micelle and formation of a ternary LpxK-ATP/Mg(2+)-DSMP complex. Using steady-state kinetics, we have identified crucial active site residues, leading to the proposal that the interaction of D99 with H261 acts to increase the pKa of the imidazole moiety, which in turn serves as the catalytic base to deprotonate the 4'-hydroxyl of the DSMP substrate. The fact that an analogous mechanism has not yet been observed for other P-loop kinases highlights LpxK as a distinct member of the P-loop kinase family, a notion that is also reflected through its localization at the membrane, lipid substrate, and overall structure.

  11. Mutagenesis of the Glucose-1-Phosphate-Binding Site of Potato Tuber ADP-Glucose Pyrophosphorylase1

    PubMed Central

    Fu, Yingbin; Ballicora, Miguel A.; Preiss, Jack

    1998-01-01

    Lysine (Lys)-195 in the homotetrameric ADP-glucose pyrophosphorylase (ADPGlc PPase) from Escherichia coli was shown previously to be involved in the binding of the substrate glucose-1-phosphate (Glc-1-P). This residue is highly conserved in the ADPGlc PPase family. Site-directed mutagenesis was used to investigate the function of this conserved Lys residue in the large and small subunits of the heterotetrameric potato (Solanum tuberosum) tuber enzyme. The apparent affinity for Glc-1-P of the wild-type enzyme decreased 135- to 550-fold by changing Lys-198 of the small subunit to arginine, alanine, or glutamic acid, suggesting that both the charge and the size of this residue influence Glc-1-P binding. These mutations had little effect on the kinetic constants for the other substrates (ATP and Mg2+ or ADP-Glc and inorganic phosphate), activator (3-phosphoglycerate), inhibitor (inorganic phosphate), or on the thermal stability. Mutagenesis of the corresponding Lys (Lys-213) in the large subunit had no effect on the apparent affinity for Glc-1-P by substitution with arginine, alanine, or glutamic acid. A double mutant, SK198RLK213R, was also obtained that had a 100-fold reduction of the apparent affinity for Glc-1-P. The data indicate that Lys-198 in the small subunit is directly involved in the binding of Glc-1-P, whereas they appear to exclude a direct role of Lys-213 in the large subunit in the interaction with this substrate. PMID:9662541

  12. Bacterial versus human sphingosine-1-phosphate lyase (S1PL) in the design of potential S1PL inhibitors.

    PubMed

    Sanllehí, Pol; Abad, José-Luis; Casas, Josefina; Bujons, Jordi; Delgado, Antonio

    2016-09-15

    A series of potential active-site sphingosine-1-phosphate lyase (S1PL) inhibitors have been designed from scaffolds 1 and 2, arising from virtual screening using the X-ray structures of the bacterial (StS1PL) and the human (hS1PL) enzymes. Both enzymes are very similar at the active site, as confirmed by the similar experimental kinetic constants shown by the fluorogenic substrate RBM13 in both cases. However, the docking scoring functions used probably overestimated the weight of electrostatic interactions between the ligands and key active-site residues in the protein environment, which may account for the modest activity found for the designed inhibitors. In addition, the possibility that the inhibitors do not reach the enzyme active site should not be overlooked. Finally, since both enzymes show remarkable structural differences at the access channel and in the proximity to the active site cavity, caution should be taken when designing inhibitors acting around that area, as evidenced by the much lower activity found in StS1PL for the potent hS1PL inhibitor D. PMID:27475537

  13. Isolation and developmental expression analysis of L-myo-inositol-1-phosphate synthase in four Actinidia species.

    PubMed

    Cui, Meng; Liang, Dong; Wu, Shan; Ma, Fengwang; Lei, Yushan

    2013-12-01

    Myo-inositol (MI) is an important polyol involved in cellular signal transduction, auxin storage, osmotic regulation, and membrane formation. It also serves as a precursor for the production of pinitol, ascorbic acid, and members of the raffinose family. The first committed step for MI formation is catalyzed by L-myo-inositol-1-phosphate synthase (MIPS). We isolated MIPS cDNA sequences from Actinidia eriantha, Actinidia rufa, and Actinidia arguta and compared them with that of Actinidia deliciosa. Each comprised 1533 bp, encoding 510 amino acids with a predicted molecular weight of 56.5 KDa. The MIPS protein was highly conserved in Actinidia, sharing 98.94% identity among species. The MIPS gene was expressed in the flowers, leaves, petioles, and carpopodia. Similarly high levels of expression were detected in the young fruit of all four species. Overall activity of the enzyme was also maximal in young fruit, indicating that this developmental stage is the key point for MI synthesis in Actinidia. Among the four species, A. arguta had the greatest concentration of MI as well as the highest ratios of MI:sucrose and MI:glucose+fructose. This suggests that conversion to MI from carbohydrates was most efficient in A. arguta during early fruit development.

  14. Periodic nanostructuring of Er/Yb-codoped IOG1 phosphate glass by using ultraviolet laser-assisted selective chemical etching

    SciTech Connect

    Pappas, C.; Pissadakis, S.

    2006-12-01

    The patterning of submicron period ({approx_equal}500 nm) Bragg reflectors in the Er/Yb-codoped IOG1 Schott, phosphate glass is demonstrated. A high yield patterning technique is presented, wherein high volume damage is induced into the glass matrix by exposure to intense ultraviolet 213 nm, 150 ps Nd:YAG laser radiation and, subsequently, a chemical development in potassium hydroxide (KOH)/ethylenediamine tetra-acetic acid (EDTA) aqueous solution selectively etches the exposed areas. The electronic changes induced by the 213 nm ultraviolet irradiation are examined by employing spectrophotometric measurements, while an estimation of the refractive index changes recorded is provided by applying Kramers-Kronig transformation to the absorption change data. In addition, real time diffraction efficiency measurements were obtained during the formation of the volume damage grating. After the exposure, the growth of the relief grating pattern in time was measured at fixed time intervals and the dependence of the grating depth on the etching time and exposure conditions is presented. The gratings fabricated are examined by atomic and scanning electron microscopies to reveal the relief topology of the structures. Gratings with average depth of 120 nm and excellent surface quality were fabricated by exposing the IOG1 phosphate glass to 36 000 pulses of 208 mJ/cm{sup 2} energy density, followed by developing in the KOH/EDTA agent for 6 min.

  15. Sphingosine 1-phosphate, a bioactive sphingolipid abundantly stored in platelets, is a normal constituent of human plasma and serum.

    PubMed

    Yatomi, Y; Igarashi, Y; Yang, L; Hisano, N; Qi, R; Asazuma, N; Satoh, K; Ozaki, Y; Kume, S

    1997-05-01

    Although sphingosine 1-phosphate (Sph-1-P) is reportedly involved in diverse cellular processes and the physiological roles of this bioactive sphingolipid have been strongly suggested, few studies have revealed the presence of Sph-1-P in human samples, including body fluids and cells, under physiological conditions. In this study, we identified Sph-1-P as a normal constituent of human plasma and serum. The Sph-1-P levels in plasma and serum were 191+/-79 and 484+/-82 pmol/ml (mean+/-SD, n=8), respectively. Furthermore, when Sph-1-P was measured in paired plasma and serum samples obtained from 6 healthy adults, the serum Sph-1-P/plasma Sph-1-P ratio was found to be 2.65+/-1.26 (mean+/-SD). It is most likely that the source of discharged Sph-1-P during blood clotting is platelets, because platelets abundantly store Sph-1-P compared with other blood cells, and release part of their stored Sph-1-P extracellularly upon stimulation. We also studied Sph-1-P-related metabolism in plasma. [3H]Sph was stable and not metabolized at all in plasma, but was rapidly incorporated into platelets and metabolized mainly to Sph-1-P in platelet-rich plasma. [3H]Sph-1-P was found to be unchanged in plasma, revealing that plasma does not contain the enzymes needed for Sph-1-P degradation. In summary, platelets can convert Sph into Sph-1-P, and are storage sites for the latter in the blood. In view of the diverse biological effects of Sph-1-P, the release of Sph-1-P from activated platelets may be involved in a variety of physiological and pathophysiological processes, including thrombosis, hemostasis, atherosclerosis and wound healing.

  16. Elevated nuclear sphingoid base-1-phosphates and decreased histone deacetylase activity after fumonisin B1 treatment in mouse embryonic fibroblasts.

    PubMed

    Gardner, Nicole M; Riley, Ronald T; Showker, Jency L; Voss, Kenneth A; Sachs, Andrew J; Maddox, Joyce R; Gelineau-van Waes, Janee B

    2016-05-01

    Fumonisin B1 (FB1) is a mycotoxin produced by a common fungal contaminant of corn. Administration of FB1 to pregnant LM/Bc mice induces exencephaly in embryos, and ingestion of FB1-contaminated food during early pregnancy is associated with increased risk for neural tube defects (NTDs) in humans. FB1 inhibits ceramide synthase enzymes in sphingolipid biosynthesis, causing sphinganine (Sa) and bioactive sphinganine-1-phosphate (Sa1P) accumulation in blood, cells, and tissues. Sphingosine kinases (Sphk) phosphorylate Sa to form Sa1P. Upon activation, Sphk1 associates primarily with the plasma membrane, while Sphk2 is found predominantly in the nucleus. In cells over-expressing Sphk2, accumulation of Sa1P in the nuclear compartment inhibits histone deacetylase (HDAC) activity, causing increased acetylation of histone lysine residues. In this study, FB1 treatment in LM/Bc mouse embryonic fibroblasts (MEFs) resulted in significant accumulation of Sa1P in nuclear extracts relative to cytoplasmic extracts. Elevated nuclear Sa1P corresponded to decreased histone deacetylase (HDAC) activity and increased histone acetylation at H2BK12, H3K9, H3K18, and H3K23. Treatment of LM/Bc MEFs with a selective Sphk1 inhibitor, PF-543, or with ABC294640, a selective Sphk2 inhibitor, significantly reduced nuclear Sa1P accumulation after FB1, although Sa1P levels remained significantly increased relative to basal levels. Concurrent treatment with both PF-543 and ABC294640 prevented nuclear accumulation of Sa1P in response to FB1. Other HDAC inhibitors are known to cause NTDs, so these results suggest that FB1-induced disruption of sphingolipid metabolism leading to nuclear Sa1P accumulation, HDAC inhibition, and histone hyperacetylation is a potential mechanism for FB1-induced NTDs. PMID:26905748

  17. Sorbitol production from lactose by engineered Lactobacillus casei deficient in sorbitol transport system and mannitol-1-phosphate dehydrogenase.

    PubMed

    De Boeck, Reinout; Sarmiento-Rubiano, Luz Adriana; Nadal, Inmaculada; Monedero, Vicente; Pérez-Martínez, Gaspar; Yebra, María J

    2010-02-01

    Sorbitol is a sugar alcohol largely used in the food industry as a low-calorie sweetener. We have previously described a sorbitol-producing Lactobacillus casei (strain BL232) in which the gutF gene, encoding a sorbitol-6-phosphate dehydrogenase, was expressed from the lactose operon. Here, a complete deletion of the ldh1 gene, encoding the main L-lactate dehydrogenase, was performed in strain BL232. In a resting cell system with glucose, the new strain, named BL251, accumulated sorbitol in the medium that was rapidly metabolized after glucose exhaustion. Reutilization of produced sorbitol was prevented by deleting the gutB gene of the phosphoenolpyruvate: sorbitol phosphotransferase system (PTS(Gut)) in BL251. These results showed that the PTS(Gut) did not mediate sorbitol excretion from the cells, but it was responsible for uptake and reutilization of the synthesized sorbitol. A further improvement in sorbitol production was achieved by inactivation of the mtlD gene, encoding a mannitol-1-phosphate dehydrogenase. The new strain BL300 (lac::gutF Deltaldh1 DeltagutB mtlD) showed an increase in sorbitol production whereas no mannitol synthesis was detected, avoiding thus a polyol mixture. This strain was able to convert lactose, the main sugar from milk, into sorbitol, either using a resting cell system or in growing cells under pH control. A conversion rate of 9.4% of lactose into sorbitol was obtained using an optimized fed-batch system and whey permeate, a waste product of the dairy industry, as substrate.

  18. GlmU (N-acetylglucosamine-1-phosphate uridyltransferase) bound to three magnesium ions and ATP at the active site

    PubMed Central

    Vithani, Neha; Bais, Vaibhav; Prakash, Balaji

    2014-01-01

    N-Acetylglucosamine-1-phosphate uridyltransferase (GlmU), a bifunctional enzyme exclusive to prokaryotes, belongs to the family of sugar nucleotidyltransferases (SNTs). The enzyme binds GlcNAc-1-P and UTP, and catalyzes a uridyltransfer reaction to synthesize UDP-GlcNAc, an important precursor for cell-wall biosynthesis. As many SNTs are known to utilize a broad range of substrates, substrate specificity in GlmU was probed using biochemical and structural studies. The enzymatic assays reported here demonstrate that GlmU is specific for its natural substrates UTP and GlcNAc-1-P. The crystal structure of GlmU bound to ATP and GlcNAc-1-P provides molecular details for the inability of the enzyme to utilize ATP for the nucleotidyltransfer reaction. ATP binding results in an inactive pre-catalytic enzyme–substrate complex, where it adopts an unusual conformation such that the reaction cannot be catalyzed; here, ATP is shown to be bound together with three Mg2+ ions. Overall, this structure represents the binding of an inhibitory molecule at the active site and can potentially be used to develop new inhibitors of the enzyme. Further, similar to DNA/RNA polymerases, GlmU was recently recognized to utilize two metal ions, MgA 2+ and MgB 2+, to catalyze the uridyltransfer reaction. Interestingly, displacement of MgB 2+ from its usual catalytically competent position, as noted in the crystal structure of RNA polymerase in an inactive state, was considered to be a key factor inhibiting the reaction. Surprisingly, in the current structure of GlmU MgB 2+ is similarly displaced; this raises the possibility that an analogous inhibitory mechanism may be operative in GlmU. PMID:24915076

  19. Sorbitol production from lactose by engineered Lactobacillus casei deficient in sorbitol transport system and mannitol-1-phosphate dehydrogenase.

    PubMed

    De Boeck, Reinout; Sarmiento-Rubiano, Luz Adriana; Nadal, Inmaculada; Monedero, Vicente; Pérez-Martínez, Gaspar; Yebra, María J

    2010-02-01

    Sorbitol is a sugar alcohol largely used in the food industry as a low-calorie sweetener. We have previously described a sorbitol-producing Lactobacillus casei (strain BL232) in which the gutF gene, encoding a sorbitol-6-phosphate dehydrogenase, was expressed from the lactose operon. Here, a complete deletion of the ldh1 gene, encoding the main L-lactate dehydrogenase, was performed in strain BL232. In a resting cell system with glucose, the new strain, named BL251, accumulated sorbitol in the medium that was rapidly metabolized after glucose exhaustion. Reutilization of produced sorbitol was prevented by deleting the gutB gene of the phosphoenolpyruvate: sorbitol phosphotransferase system (PTS(Gut)) in BL251. These results showed that the PTS(Gut) did not mediate sorbitol excretion from the cells, but it was responsible for uptake and reutilization of the synthesized sorbitol. A further improvement in sorbitol production was achieved by inactivation of the mtlD gene, encoding a mannitol-1-phosphate dehydrogenase. The new strain BL300 (lac::gutF Deltaldh1 DeltagutB mtlD) showed an increase in sorbitol production whereas no mannitol synthesis was detected, avoiding thus a polyol mixture. This strain was able to convert lactose, the main sugar from milk, into sorbitol, either using a resting cell system or in growing cells under pH control. A conversion rate of 9.4% of lactose into sorbitol was obtained using an optimized fed-batch system and whey permeate, a waste product of the dairy industry, as substrate. PMID:19784641

  20. Synthesis, stereochemical determination and biochemical characterization of the enantiomeric phosphate esters of the novel immunosuppressive agent FTY720.

    PubMed

    Hale, Jeffrey J; Yan, Lin; Neway, William E; Hajdu, Richard; Bergstrom, James D; Milligan, James A; Shei, Gan-Ju; Chrebet, Gary L; Thornton, Rosemary A; Card, Deborah; Rosenbach, Mark; HughRosen; Mandala, Suzanne

    2004-09-15

    The novel immunosuppressive agent FTY720 (1) is phosphorylated in vivo in a variety of species yielding an active metabolite that is an agonist of four of the five known G-protein-coupled sphingosine-1-phosphate (S1P) receptors. A synthesis amenable to producing gram quantities of the stereoisomeric phosphate esters, a determination of their absolute stereochemistry via an enantioselective synthesis and their characterization as S1P receptor agonists and antagonists is reported.

  1. Chitosan/glucose 1-phosphate as new stable in situ forming depot system for controlled drug delivery.

    PubMed

    Supper, Stephanie; Anton, Nicolas; Boisclair, Julie; Seidel, Nina; Riemenschnitter, Marc; Curdy, Catherine; Vandamme, Thierry

    2014-10-01

    Chitosan (CS)-based thermosensitive solutions that turn into semi-solid hydrogels upon injection at body temperature have increasingly drawn attention over the last decades as an attractive new type of in situ forming depot (ISFD) drug delivery system. Despite the great potential of the standard CS/β-glycerophosphate (β-GP) thermogelling solutions, their lack of stability over time at room temperature as well as at refrigerated conditions renders them unsuitable as ready-to-use drug product. In the present study, we investigated Glucose-1-Phosphate (G1-P) as an alternative gelling agent for improving the stability of CS-based ISFD solutions. The in vitro release performance of CS/G1-P formulations was assessed using several model compounds. Furthermore, the local tolerance of subcutaneously implanted CS/G1-P hydrogels was investigated by histological examination over three weeks. The thermogelling potential of CS/G1-P solutions, determined by rheology, is dependent on the polymer molecular weight (Mw) and concentration as well as on the G1-P concentration. Differential scanning calorimetry (DSC) measurements confirmed that sol/gel transition takes place at around body temperature and is not fully thermo-reversible. The long term storage stability was evaluated through the appearance, pH, viscosity and gelation time at 37°C of the solution. The results emphasized an enhanced stability of the CS/G1-P system compared to the standard CS/β-GP. CS solution with 0.40 mmol/g G1-P is stable for at least 9 months at 2-8°C, versus less than 1 month when using β-GP as gelling agent. Furthermore, the solution is easy to inject, as evidenced from injectability evaluation using 23-30 G needles. In vitro release experiments showed a sustained release over days to weeks for hydrophilic model compounds, demonstrating thereby that CS/G1-P may be suitable for the prolonged delivery of drugs. The inflammatory reaction observed in the tissue surrounding the hydrogel in rats was a

  2. Developmental delay in a Streptomyces venezuelae glgE null mutant is associated with the accumulation of α-maltose 1-phosphate.

    PubMed

    Miah, Farzana; Bibb, Maureen J; Barclay, J Elaine; Findlay, Kim C; Bornemann, Stephen

    2016-07-01

    The GlgE pathway is thought to be responsible for the conversion of trehalose into a glycogen-like α-glucan polymer in bacteria. Trehalose is first converted to maltose, which is phosphorylated by maltose kinase Pep2 to give α-maltose 1-phosphate. This is the donor substrate of the maltosyl transferase GlgE that is known to extend α-1,4-linked maltooligosaccharides, which are thought to be branched with α-1,6 linkages. The genome of Streptomyces venezuelae contains all the genes coding for the GlgE pathway enzymes but none of those of related pathways, including glgC and glgA of the glycogen pathway. This provides an opportunity to study the GlgE pathway in isolation. The genes of the GlgE pathway were upregulated at the onset of sporulation, consistent with the known timing of α-glucan deposition. A constructed ΔglgE null mutant strain was viable but showed a delayed developmental phenotype when grown on maltose, giving less cell mass and delayed sporulation. Pre-spore cells and spores of the mutant were frequently double the length of those of the wild-type, implying impaired cross-wall formation, and spores showed reduced tolerance to stress. The mutant accumulated α-maltose 1-phosphate and maltose but no α-glucan. Therefore, the GlgE pathway is necessary and sufficient for polymer biosynthesis. Growth of the ΔglgE mutant on galactose and that of a Δpep2 mutant on maltose were analysed. In both cases, neither accumulation of α-maltose 1-phosphate/α-glucan nor a developmental delay was observed. Thus, high levels of α-maltose 1-phosphate are responsible for the developmental phenotype of the ΔglgE mutant, rather than the lack of α-glucan.

  3. Receptor binding properties of amperozide.

    PubMed

    Svartengren, J; Simonsson, P

    1990-01-01

    The receptor pharmacology of amperozide was investigated with in vitro radioligand binding technique. Amperozide possessed a high affinity to the 5-HT2 receptors (Ki = 16.5 +/- 2.1 nM) and a moderate affinity to alpha 1-adrenergic receptors of rat cerebral cortical membranes (Ki = 172 +/- 14 nM). The affinity of amperozide for striatal and limbic dopamine D2 receptors was low and not significantly different (Ki +/- S.E.M. = 540 +/- 59 nM vs 403 +/- 42 nM; p less than 0.11, n = 4). The affinity for striatal and limbic 5-HT2 receptors was measured as well and found to be very close to the affinity to the cerebral cortical 5-HT2 receptor. The drug affinity for D2 and 5-HT2 receptors seems thus not to be influenced by the location of the receptor moiety. The affinity for several other rat brain receptors such as 5-HT1A, alpha 2-adrenergic, dopamine D1, muscarinic M1 and M2, opiate sigma and beta 2-adrenergic was low. The pseudo-Hill coefficient of the amperozide competition binding curve was consistently higher than one indicating antagonistic and complex interactions with the 5-HT2 receptor or with alpha 1-adrenergic and dopamine D2 receptors. The antagonistic properties of amperozide were investigated by its ability to antagonize the serotonin-induced formation of inositol-1-phosphate in human blood platelets. Amperozide inhibited this 5-HT2 receptor-mediated intracellular response with similar potency as ketanserin. These results suggest that amperozide is a selective 5-HT2 receptor antagonist.

  4. Synthesis and biological evaluation of phosphoramidate prodrugs of two analogues of 2-deoxy-d-ribose-1-phosphate directed to the discovery of two carbasugars as new potential anti-HIV leads.

    PubMed

    Hamon, Nadège; Slusarczyk, Magdalena; Serpi, Michaela; Balzarini, Jan; McGuigan, Christopher

    2015-02-15

    2-Deoxy-α-d-ribose-1-phosphate is of great interest as it is involved in the biosynthesis and/or catabolic degradation of several nucleoside analogues of biological and therapeutic relevance. However due to the lack of a stabilising group at its 2-position, it is difficult to synthesize stable prodrugs of this compound. In order to overcome this lack of stability, the synthesis of carbasugar analogues of 2-deoxyribose-1-phosphate was envisioned. Herein the preparation of a series of prodrugs of two carbocyclic analogues of 2-deoxyribose-1-phosphate using the phosphoramidate ProTide technology, along with their biological evaluation against HIV and cancer cell proliferation, is reported.

  5. Structural Insight into How Streptomyces coelicolor Maltosyl Transferase GlgE Binds α-Maltose 1-Phosphate and Forms a Maltosyl-enzyme Intermediate

    PubMed Central

    2014-01-01

    GlgE (EC 2.4.99.16) is an α-maltose 1-phosphate:(1→4)-α-d-glucan 4-α-d-maltosyltransferase of the CAZy glycoside hydrolase 13_3 family. It is the defining enzyme of a bacterial α-glucan biosynthetic pathway and is a genetically validated anti-tuberculosis target. It catalyzes the α-retaining transfer of maltosyl units from α-maltose 1-phosphate to maltooligosaccharides and is predicted to use a double-displacement mechanism. Evidence of this mechanism was obtained using a combination of site-directed mutagenesis of Streptomyces coelicolor GlgE isoform I, substrate analogues, protein crystallography, and mass spectrometry. The X-ray structures of α-maltose 1-phosphate bound to a D394A mutein and a β-2-deoxy-2-fluoromaltosyl-enzyme intermediate with a E423A mutein were determined. There are few examples of CAZy glycoside hydrolase family 13 members that have had their glycosyl-enzyme intermediate structures determined, and none before now have been obtained with a 2-deoxy-2-fluoro substrate analogue. The covalent modification of Asp394 was confirmed using mass spectrometry. A similar modification of wild-type GlgE proteins from S. coelicolor and Mycobacterium tuberculosis was also observed. Small-angle X-ray scattering of the M. tuberculosis enzyme revealed a homodimeric assembly similar to that of the S. coelicolor enzyme but with slightly differently oriented monomers. The deeper understanding of the structure–function relationships of S. coelicolor GlgE will aid the development of inhibitors of the M. tuberculosis enzyme. PMID:24689960

  6. Physiological aggregation of maltodextrin phosphorylase from Pyrococcus furiosus and its application in a process of batch starch degradation to alpha-D-glucose-1-phosphate.

    PubMed

    Nahálka, Jozef

    2008-04-01

    Maltodextrin phosphorylase from Pyrococcus furiosus (PF1535) was fused with the cellulose-binding domain of Clostridium cellulovorans serving as an aggregation module. After molecular cloning of the corresponding gene fusion construct and controlled expression in Escherichia coli BL21, 83% of total maltodextrin phosphorylase activity (0.24 U/mg