@article{BarceloCoblijnLauraMartindeAlmeidaetal.2011, author = {Barcelo-Coblijn, Gwendolyn and Laura Martin, Maria and de Almeida, Rodrigo F. M. and Antonia Noguera-Salva, Maria and Marcilla-Etxenike, Amaia and Guardiola-Serrano, Francisca and Lueth, Anja and Kleuser, Burkhard and Halver, John E. and Escriba, Pablo V.}, title = {Sphingomyelin and sphingomyelin synthase (SMS) in the malignant transformation of glioma cells and in 2-hydroxyoleic acid therapy}, series = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {108}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, number = {49}, publisher = {National Acad. of Sciences}, address = {Washington}, issn = {0027-8424}, doi = {10.1073/pnas.1115484108}, pages = {19569 -- 19574}, year = {2011}, abstract = {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.}, language = {en} } @misc{BaeumerRossbachMischkeetal.2011, author = {B{\"a}umer, Wolfgang and Rossbach, Kristine and Mischke, Reinhard and Reines, Ilka and Langbein-Detsch, Ines and L{\"u}th, Anja and Kleuser, Burkhard}, title = {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}, series = {The journal of investigative dermatology}, volume = {131}, journal = {The journal of investigative dermatology}, number = {1}, publisher = {Nature Publ. Group}, address = {New York}, issn = {0022-202X}, doi = {10.1038/jid.2010.252}, pages = {266 -- 268}, year = {2011}, language = {en} } @article{LuethNeuberKleuser2012, author = {L{\"u}th, Anja and Neuber, Corinna and Kleuser, Burkhard}, title = {Novel methods for the quantification of (2E)-hexadecenal by liquid chromatography with detection by either ESI QTOF tandem mass spectrometry or fluorescence measurement}, series = {Analytica chimica acta : an international journal devoted to all branches of analytical chemistry}, volume = {722}, journal = {Analytica chimica acta : an international journal devoted to all branches of analytical chemistry}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0003-2670}, doi = {10.1016/j.aca.2012.01.063}, pages = {70 -- 79}, year = {2012}, abstract = {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.}, language = {en} } @inproceedings{BoehmPolzinLuethetal.2012, author = {Boehm, Andreas and Polzin, A. and Lueth, Anja and Kleuser, Burkhard and Rassaf, T. and Kelm, M. and Kroemer, H. K. and Schroer, K. and Rauch, B. H.}, title = {The release of sphingosine-1-phosphate from human platelets during acute coronary syndrome is attenuated by aspirin}, series = {NAUNYN-SCHMIEDEBERGS ARCHIVES OF PHARMACOLOGY}, volume = {385}, booktitle = {NAUNYN-SCHMIEDEBERGS ARCHIVES OF PHARMACOLOGY}, publisher = {Springer}, address = {New York}, issn = {0028-1298}, pages = {12 -- 12}, year = {2012}, language = {en} } @inproceedings{SchaperKietzmannKleuseretal.2012, author = {Schaper, K. and Kietzmann, M. and Kleuser, Burkhard and Baeumer, W.}, title = {Effects of sphingosine-1-phosphate and FTY720 on epidermal hyperproliferation and inflammation in an imiquimod induced mouse model of psoriasis}, series = {NAUNYN-SCHMIEDEBERGS ARCHIVES OF PHARMACOLOGY}, volume = {385}, booktitle = {NAUNYN-SCHMIEDEBERGS ARCHIVES OF PHARMACOLOGY}, number = {3}, publisher = {Springer}, address = {New York}, issn = {0028-1298}, pages = {80 -- 80}, year = {2012}, language = {en} } @article{GereckeMascherGottschalketal.2013, author = {Gerecke, Christian and Mascher, Conny and Gottschalk, Uwe and Kleuser, Burkhard and Scholtka, Bettina}, title = {Ultrasensitive detection of unknown colon cancer-initiating mutations using the example of the adenomatous polyposis coli gene}, series = {Cancer prevention research}, volume = {6}, journal = {Cancer prevention research}, number = {9}, publisher = {American Association for Cancer Research}, address = {Philadelphia}, issn = {1940-6207}, doi = {10.1158/1940-6207.CAPR-13-0145}, pages = {898 -- 907}, year = {2013}, abstract = {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.}, language = {en} } @article{LotinunKivirantaMatsubaraetal.2013, author = {Lotinun, Sutada and Kiviranta, Riku and Matsubara, Takuma and Alzate, Jorge A. and Neff, Lynn and L{\"u}th, Anja and Koskivirta, Ilpo and Kleuser, Burkhard and Vacher, Jean and Vuorio, Eero and Horne, William C. and Baron, Roland}, title = {Osteoclast-specific cathepsin K deletion stimulates S1P-dependent bone formation}, series = {The journal of clinical investigation}, volume = {123}, journal = {The journal of clinical investigation}, number = {2}, publisher = {American Society for Clinical Investigation}, address = {Ann Arbor}, issn = {0021-9738}, doi = {10.1172/JCI64840}, pages = {666 -- 681}, year = {2013}, abstract = {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.}, language = {en} } @misc{PolzinRassafBoehmetal.2013, author = {Polzin, Amin and Rassaf, Tienush and Boehm, Andreas and Lueth, Anja and Kleuser, Burkhard and Zeus, Tobias and Kelm, Malte and Kroemer, Heyo K. and Schroer, Karsten and Rauch, Bernhard H.}, title = {Aspirin inhibits release of platelet-derived sphingosine-1-phosphate in acute myocardial infarction}, series = {INTERNATIONAL JOURNAL OF CARDIOLOGY}, volume = {170}, journal = {INTERNATIONAL JOURNAL OF CARDIOLOGY}, number = {2}, publisher = {ELSEVIER IRELAND LTD}, address = {CLARE}, issn = {0167-5273}, doi = {10.1016/j.ijcard.2013.10.050}, pages = {E23 -- E24}, year = {2013}, language = {en} } @article{BoehmFloesserErmleretal.2013, author = {B{\"o}hm, Andreas and Fl{\"o}ßer, Anja and Ermler, Swen and Fender, Anke C. and L{\"u}th, Anja and Kleuser, Burkhard and Schr{\"o}r, Karsten and Rauch, Bernhard H.}, title = {Factor-Xa-induced mitogenesis and migration require sphingosine kinase activity and S1P formation in human vascular smooth muscle cells}, series = {Cardiovascular research}, volume = {99}, journal = {Cardiovascular research}, number = {3}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0008-6363}, doi = {10.1093/cvr/cvt112}, pages = {505 -- 513}, year = {2013}, abstract = {Sphingosine-1-phosphate (S1P) is a cellular signalling lipid generated by sphingosine kinase-1 (SPHK1). The aim of the study was to investigate whether the activated coagulation factor-X (FXa) regulates SPHK1 transcription and the formation of S1P and subsequent mitogenesis and migration of human vascular smooth muscle cells (SMC). FXa induced a time- (36 h) and concentration-dependent (330 nmol/L) increase of SPHK1 mRNA and protein expression in human aortic SMC, resulting in an increased synthesis of S1P. FXa-stimulated transcription of SPHK1 was mediated by the protease-activated receptor-1 (PAR-1) and PAR-2. In human carotid artery plaques, expression of SPHK1 was observed at SMC-rich sites and was co-localized with intraplaque FX/FXa content. FXa-induced SPHK1 transcription was attenuated by inhibitors of Rho kinase (Y27632) and by protein kinase C (PKC) isoforms (GF109203X). In addition, FXa rapidly induced the activation of the small GTPase Rho A. Inhibition of signalling pathways which regulate SPHK1 expression, inhibition of its activity or siRNA-mediated SPHK1 knockdown attenuated the mitogenic and chemotactic response of human SMC to FXa. These data suggest that FXa induces SPHK1 expression and increases S1P formation independent of thrombin and that this involves the activation of Rho A and PKC signalling. In addition to its key function in coagulation, this direct effect of FXa on human SMC may increase cell proliferation and migration at sites of vessel injury and thereby contribute to the progression of vascular lesions.}, language = {en} } @article{SchaperDickhautJaptoketal.2013, author = {Schaper, Katrin and Dickhaut, Jeannette and Japtok, Lukasz and Kietzmann, Manfred and Mischke, Reinhard and Kleuser, Burkhard and B{\"a}umer, Wolfgang}, title = {Sphingosine-1-phosphate exhibits anti-proliferative and anti-inflammatory effects in mouse models of psoriasis}, series = {Journal of dermatological scienc}, volume = {71}, journal = {Journal of dermatological scienc}, number = {1}, publisher = {Elsevier}, address = {Clare}, issn = {0923-1811}, doi = {10.1016/j.jdermsci.2013.03.006}, pages = {29 -- 36}, year = {2013}, abstract = {Background: It has been indicated that the sphingolipid sphingosine-1-phosphate (SIP) restrains the ability of dendritic cells to migrate to lymph nodes. Furthermore SIP has been demonstrated to inhibit cell growth in human keratinocytes. However, only little is known about the effect of S1P in hyperproliferative and inflammatory in vivo models. Objective: In this study, locally acting SIP was explored in different experimental mouse models of psoriasis vulgaris. Methods: S1P and FTY720 were tested in the imiquimod-induced psoriasis mouse model, the mouse tail assay and a pilot study of the severe combined immunodeficiency mice (SCID). Results: In the imiquimod model the positive control diflorasone diacetate and S1P, but not FTY720 reduced the imiquimod-induced epidermal hyperproliferation of the ear skin. This effect was confirmed in the SCID model, where S1P treated skin from patients suffering from psoriasis showed a decrease in epidermal thickness compared to vehicle. In the imiquimod model, there was also significant inhibition of ear swelling and a moderate reduction of inflammatory cell influx and oedema formation in ear skin by SIP treatment. The inflammatory response on the back skin was, however, only reduced by diflorasone diacetate. In the mouse tail assay, the influence of S1P and FTY720 in stratum granulosum formation was tested compared to the positive control calcipotriol. Whereas topical administration of calcipotriol led to a low but significant increase of stratum granulosum, S1P and FTY720 lacked such an effect. Conclusion: Taken together, these results imply that topical administration of SIP might be a new option for the treatment of mild to moderate psoriasis lesions.}, language = {en} }