TY - JOUR A1 - Barcelo-Coblijn, Gwendolyn A1 - Laura Martin, Maria A1 - de Almeida, Rodrigo F. M. A1 - Antonia Noguera-Salva, Maria A1 - Marcilla-Etxenike, Amaia A1 - Guardiola-Serrano, Francisca A1 - Lueth, Anja A1 - Kleuser, Burkhard A1 - Halver, John E. A1 - Escriba, Pablo V. T1 - Sphingomyelin and sphingomyelin synthase (SMS) in the malignant transformation of glioma cells and in 2-hydroxyoleic acid therapy JF - Proceedings of the National Academy of Sciences of the United States of America N2 - The mechanism of action of 2-hydroxyoleic acid (2OHOA), a potent antitumor compound, has not yet been fully elucidated. Here, we show that human cancer cells have markedly lower levels of sphingomyelin (SM) than nontumor (MRC-5) cells. In this context, 2OHOA treatment strongly augments SM mass (4.6-fold), restoring the levels found in MRC-5 cells, while a loss of phosphatidylethanolamine and phosphatidylcholine is observed (57 and 30%, respectively). The increased SM mass was due to a rapid and highly specific activation of SM synthases (SMS). This effect appeared to be specific against cancer cells as it did not affect nontumor MRC-5 cells. Therefore, low SM levels are associated with the tumorigenic transformation that produces cancer cells. SM accumulation occurred at the plasma membrane and caused an increase in membrane global order and lipid raft packing in model membranes. These modifications would account for the observed alteration by 2OHOA in the localization of proteins involved in cell apoptosis (Fas receptor) or differentiation (Ras). Importantly, SMS inhibition by D609 diminished 2OHOA effect on cell cycle. Therefore, we propose that the regulation of SMS activity in tumor cells is a critical upstream event in 2OHOA antitumor mechanism, which also explains its specificity for cancer cells, its potency, and the lack of undesired side effects. Finally, the specific activation of SMS explains the ability of this compound to trigger cell cycle arrest, cell differentiation, and autophagy or apoptosis in cancer cells. KW - anticancer KW - membrane-lipid therapy KW - lung cancer KW - membrane lipids Y1 - 2011 U6 - https://doi.org/10.1073/pnas.1115484108 SN - 0027-8424 VL - 108 IS - 49 SP - 19569 EP - 19574 PB - National Acad. of Sciences CY - Washington ER - TY - GEN A1 - Bäumer, Wolfgang A1 - Rossbach, Kristine A1 - Mischke, Reinhard A1 - Reines, Ilka A1 - Langbein-Detsch, Ines A1 - Lüth, Anja A1 - Kleuser, Burkhard T1 - Decreased concentration and enhanced metabolism of sphingosine-1-Phosphate in lesional skin of dogs with atopic dermatitis disturbed Sphingosine-1-Phosphate homeostasis in atopic Dermatitis T2 - The journal of investigative dermatology Y1 - 2011 U6 - https://doi.org/10.1038/jid.2010.252 SN - 0022-202X VL - 131 IS - 1 SP - 266 EP - 268 PB - Nature Publ. Group CY - New York ER - TY - JOUR A1 - Lüth, Anja A1 - Neuber, Corinna A1 - Kleuser, Burkhard T1 - Novel methods for the quantification of (2E)-hexadecenal by liquid chromatography with detection by either ESI QTOF tandem mass spectrometry or fluorescence measurement JF - Analytica chimica acta : an international journal devoted to all branches of analytical chemistry N2 - Sphingosine-1-phosphate lyase (SPL) is the only known enzyme that irreversibly cleaves sphingosine-1-phosphate (S1P) into phosphoethanolamine and (2E)-hexadecenal during the final step of sphingolipid catabolism. Because S1P is involved in a wide range of physiological and diseased processes, determining the activity of the degrading enzyme is of great interest. Therefore, we developed two procedures based on liquid chromatography (LC) for analysing (2E)-hexadecenal, which is one of the two S1P degradation products. After separation, two different quantification methods were performed, tandem mass spectrometry (MS) and fluorescence detection. However, (2E)-hexadecenal as a long-chain aldehyde is not ionisable by electrospray ionisation (ESI) for MS quantification and has an insufficient number of corresponding double bonds for fluorescence detection. Therefore, we investigated 2-diphenylacetyl-1,3-indandione-1-hydrazone (DAIH) as a derivatisation reagent. DAIH transforms the aldehyde into an ionisable and fluorescent analogue for quantitative analysis. Our conditions were optimised to obtain the outstanding limit of detection (LOD) of 1 fmol per sample (30 mu L) for LC-MS/MS and 0.75 pmol per sample (200 mu l) for LC determination with fluorescence detection. We developed an extraction procedure to separate and concentrate (2E)-hexadecenal from biological samples for these measurements. To confirm our new methods, we analysed the (2E)-hexadecenal level of different cell lines and human plasma for the first time ever. Furthermore, we treated HT-29 cells with different concentrations of 4-deoxypyridoxine (DOP), which competitively inhibits pyridoxal-5-phosphate (P5P), an essential cofactor for SPL activity, and observed a significant decrease in (2E)-hexadecenal relative to the untreated cells. KW - (2E)-Hexadecenal KW - Sphingosine-1-phosphate lyase KW - Derivatisation KW - Tandem mass spectrometry KW - Fluorescence Y1 - 2012 U6 - https://doi.org/10.1016/j.aca.2012.01.063 SN - 0003-2670 VL - 722 SP - 70 EP - 79 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Boehm, Andreas A1 - Polzin, A. A1 - Lueth, Anja A1 - Kleuser, Burkhard A1 - Rassaf, T. A1 - Kelm, M. A1 - Kroemer, H. K. A1 - Schroer, K. A1 - Rauch, B. H. T1 - The release of sphingosine-1-phosphate from human platelets during acute coronary syndrome is attenuated by aspirin T2 - NAUNYN-SCHMIEDEBERGS ARCHIVES OF PHARMACOLOGY Y1 - 2012 SN - 0028-1298 VL - 385 SP - 12 EP - 12 PB - Springer CY - New York ER - TY - CHAP A1 - Schaper, K. A1 - Kietzmann, M. A1 - Kleuser, Burkhard A1 - Baeumer, W. T1 - Effects of sphingosine-1-phosphate and FTY720 on epidermal hyperproliferation and inflammation in an imiquimod induced mouse model of psoriasis T2 - NAUNYN-SCHMIEDEBERGS ARCHIVES OF PHARMACOLOGY Y1 - 2012 SN - 0028-1298 VL - 385 IS - 3 SP - 80 EP - 80 PB - Springer CY - New York ER - TY - JOUR A1 - Schmitz, Elisabeth I. A1 - Potteck, Henrik A1 - Schüppel, Melanie A1 - Manggau, Marianti A1 - Wahydin, Elly A1 - Kleuser, Burkhard T1 - Sphingosine 1-phosphate protects primary human keratinocytes from apoptosis via nitric oxide formation through the receptor subtype S1P(3) JF - Molecular and cellular biochemistry : an international journal for chemical biology in health and disease N2 - Although the lipid mediator sphingosine 1-phosphate (S1P) has been identified to induce cell growth arrest of human keratinocytes, the sphingolipid effectively protects these epidermal cells from apoptosis. The molecular mechanism of the anti-apoptotic action induced by S1P is less characterized. Apart from S1P, endogenously produced nitric oxide (NOaEuro cent) has been recognized as a potent modulator of apoptosis in keratinocytes. Therefore, it was of great interest to elucidate whether S1P protects human keratinocytes via a NOaEuro cent-dependent signalling pathway. Indeed, S1P induced an activation of endothelial nitric oxide synthase (eNOS) in human keratinocytes leading to an enhanced formation of NOaEuro cent. Most interestingly, the cell protective effect of S1P was almost completely abolished in the presence of the eNOS inhibitor L-NAME as well as in eNOS-deficient keratinocytes indicating that the sphingolipid metabolite S1P protects human keratinocytes from apoptosis via eNOS activation and subsequent production of protective amounts of NOaEuro cent. It is well established that most of the known actions of S1P are mediated by a family of five specific G protein-coupled receptors. Therefore, the involvement of S1P-receptor subtypes in S1P-mediated eNOS activation has been examined. Indeed, this study clearly shows that the S1P(3) is the exclusive receptor subtype in human keratinocytes which mediates eNOS activation and NOaEuro cent formation in response to S1P. In congruence, when the S1P(3) receptor subtype is abrogated, S1P almost completely lost its ability to protect human keratinocytes from apoptosis. KW - Keratinocytes KW - Sphingolipids KW - Sphingosine 1-phosphate KW - S1P-receptors KW - Nitric oxide KW - Endothelial nitric oxide synthase KW - Apoptosis Y1 - 2012 U6 - https://doi.org/10.1007/s11010-012-1433-5 SN - 0300-8177 VL - 371 IS - 1-2 SP - 165 EP - 176 PB - Springer CY - Dordrecht ER - TY - CHAP A1 - Natek, M. A1 - Lüth, Anja A1 - Kleuser, Burkhard A1 - Schäfer-Korting, M. A1 - Weindl, G. T1 - CpG-oligonucleotides modulate sphingosine-1-phosphate metabolism in normal human keratinocytes T2 - The journal of investigative dermatology Y1 - 2012 SN - 0022-202X VL - 132 IS - 5 SP - S112 EP - S112 PB - Nature Publ. Group CY - New York ER - TY - JOUR A1 - Japtok, Lukasz A1 - Schaper, Katrin A1 - Bäumer, Wolfgang A1 - Radeke, Heinfried H. A1 - Jeong, Se Kyoo A1 - Kleuser, Burkhard T1 - Sphingosine 1-Phosphate Modulates Antigen Capture by Murine Langerhans Cells via the S1P(2) Receptor Subtype JF - PLOS ONE N2 - Dendritic cells (DCs) play a pivotal role in the development of cutaneous contact hypersensitivity (CHS) and atopic dermatitis as they capture and process antigen and present it to T lymphocytes in the lymphoid organs. Recently, it has been indicated that a topical application of the sphingolipid sphingosine 1-phosphate (S1P) prevents the inflammatory response in CHS, but the molecular mechanism is not fully elucidated. Here we indicate that treatment of mice with S1P is connected with an impaired antigen uptake by Langerhans cells (LCs), the initial step of CHS. Most of the known actions of S1P are mediated by a family of five specific G protein-coupled receptors. Our results indicate that S1P inhibits macropinocytosis of the murine LC line XS52 via S1P(2) receptor stimulation followed by a reduced phosphatidylinositol 3-kinase (PI3K) activity. As down-regulation of S1P(2) not only diminished S1P-mediated action but also enhanced the basal activity of LCs on antigen capture, an autocrine action of S1P has been assumed. Actually, S1P is continuously produced by LCs and secreted via the ATP binding cassette transporter ABCC1 to the extracellular environment. Consequently, inhibition of ABCC1, which decreased extracellular S1P levels, markedly increased the antigen uptake by LCs. Moreover, stimulation of sphingosine kinase activity, the crucial enzyme for S1P formation, is connected not only with enhanced S1P levels but also with diminished antigen capture. These results indicate that S1P is essential in LC homeostasis and influences skin immunity. This is of importance as previous reports suggested an alteration of S1P levels in atopic skin lesions. Citation: Japtok L, Schaper K, Baumer W, Radeke HH, Jeong SK, et al. (2012) Sphingosine 1-Phosphate Modulates Antigen Capture by Murine Langerhans Cells via the S1P(2) Receptor Subtype. PLoS ONE 7(11): e49427. doi:10.1371/journal.pone.0049427 Y1 - 2012 U6 - https://doi.org/10.1371/journal.pone.0049427 SN - 1932-6203 VL - 7 IS - 11 PB - PUBLIC LIBRARY SCIENCE CY - SAN FRANCISCO ER - TY - JOUR A1 - Gerecke, Christian A1 - Mascher, Conny A1 - Gottschalk, Uwe A1 - Kleuser, Burkhard A1 - Scholtka, Bettina T1 - Ultrasensitive detection of unknown colon cancer-initiating mutations using the example of the adenomatous polyposis coli gene JF - Cancer prevention research N2 - Detection of cancer precursors contributes to cancer prevention, for example, in the case of colorectal cancer. To record more patients early, ultrasensitive methods are required for the purpose of noninvasive precursor detection in body fluids. Our aim was to develop a method for enrichment and detection of known as well as unknown driver mutations in the Adenomatous polyposis coli (APC) gene. By coupled wild-type blocking (WTB) PCR and high-resolution melting (HRM), referred to as WTB-HRM, a minimum detection limit of 0.01% mutant in excess wild-type was achieved according to as little as 1 pg mutated DNA in the assay. The technique was applied to 80 tissue samples from patients with colorectal cancer (n = 17), adenomas (n = 50), serrated lesions (n = 8), and normal mucosa (n = 5). Any kind of known and unknown APC mutations (deletions, insertions, and base exchanges) being situated inside the mutation cluster region was distinguishable from wild-type DNA. Furthermore, by WTB-HRM, nearly twice as many carcinomas and 1.5 times more precursor lesions were identified to be mutated in APC, as compared with direct sequencing. By analyzing 31 associated stool DNA specimens all but one of the APC mutations could be recovered. Transferability of the WTB-HRM method to other genes was proven using the example of KRAS mutation analysis. In summary, WTB-HRM is a new approach for ultrasensitive detection of cancer-initiating mutations. In this sense, it appears especially applicable for noninvasive detection of colon cancer precursors in body fluids with excess wild-type DNA like stool. Cancer Prev Res; 6(9); 898-907. (C) 2013 AACR. Y1 - 2013 U6 - https://doi.org/10.1158/1940-6207.CAPR-13-0145 SN - 1940-6207 VL - 6 IS - 9 SP - 898 EP - 907 PB - American Association for Cancer Research CY - Philadelphia ER - TY - JOUR A1 - Lotinun, Sutada A1 - Kiviranta, Riku A1 - Matsubara, Takuma A1 - Alzate, Jorge A. A1 - Neff, Lynn A1 - Lüth, Anja A1 - Koskivirta, Ilpo A1 - Kleuser, Burkhard A1 - Vacher, Jean A1 - Vuorio, Eero A1 - Horne, William C. A1 - Baron, Roland T1 - Osteoclast-specific cathepsin K deletion stimulates S1P-dependent bone formation JF - The journal of clinical investigation N2 - Cathepsin K (CTSK) is secreted by osteoclasts to degrade collagen and other matrix proteins during bone resorption. Global deletion of Ctsk in mice decreases bone resorption, leading to osteopetrosis, but also increases the bone formation rate (BFR). To understand how Ctsk deletion increases the BFR, we generated osteoclast- and osteoblast-targeted Ctsk knockout mice using floxed Ctsk alleles. Targeted ablation of Ctsk in hematopoietic cells, or specifically in osteoclasts and cells of the monocyte-osteoclast lineage, resulted in increased bone volume and BFR as well as osteoclast and osteoblast numbers. In contrast, targeted deletion of Ctsk in osteoblasts had no effect on bone resorption or BFR, demonstrating that the increased BFR is osteoclast dependent. Deletion of Ctsk in osteoclasts increased their sphingosine kinase 1 (Sphk1) expression. Conditioned media from Ctsk-deficient osteoclasts, which contained elevated levels of sphingosine-l-phosphate (S1P), increased alkaline phosphatase and mineralized nodules in osteoblast cultures. An S1P(1,3) receptor antagonist inhibited these responses. Osteoblasts derived from mice with Ctsk-deficient osteoclasts had an increased RANKL/OPG ratio, providing a positive feedback loop that increased the number of osteoclasts. Our data provide genetic evidence that deletion of CTSK in osteoclasts enhances bone formation in vivo by increasing the generation of osteoclast-derived S1P. Y1 - 2013 U6 - https://doi.org/10.1172/JCI64840 SN - 0021-9738 VL - 123 IS - 2 SP - 666 EP - 681 PB - American Society for Clinical Investigation CY - Ann Arbor ER -