@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{SchmitzPotteckSchueppeletal.2012, author = {Schmitz, Elisabeth I. and Potteck, Henrik and Sch{\"u}ppel, Melanie and Manggau, Marianti and Wahydin, Elly and Kleuser, Burkhard}, title = {Sphingosine 1-phosphate protects primary human keratinocytes from apoptosis via nitric oxide formation through the receptor subtype S1P(3)}, series = {Molecular and cellular biochemistry : an international journal for chemical biology in health and disease}, volume = {371}, journal = {Molecular and cellular biochemistry : an international journal for chemical biology in health and disease}, number = {1-2}, publisher = {Springer}, address = {Dordrecht}, issn = {0300-8177}, doi = {10.1007/s11010-012-1433-5}, pages = {165 -- 176}, year = {2012}, abstract = {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.}, language = {en} } @inproceedings{NatekLuethKleuseretal.2012, author = {Natek, M. and L{\"u}th, Anja and Kleuser, Burkhard and Sch{\"a}fer-Korting, M. and Weindl, G.}, title = {CpG-oligonucleotides modulate sphingosine-1-phosphate metabolism in normal human keratinocytes}, series = {The journal of investigative dermatology}, volume = {132}, booktitle = {The journal of investigative dermatology}, number = {5}, publisher = {Nature Publ. Group}, address = {New York}, issn = {0022-202X}, pages = {S112 -- S112}, year = {2012}, language = {en} } @article{JaptokSchaperBaeumeretal.2012, author = {Japtok, Lukasz and Schaper, Katrin and B{\"a}umer, Wolfgang and Radeke, Heinfried H. and Jeong, Se Kyoo and Kleuser, Burkhard}, title = {Sphingosine 1-Phosphate Modulates Antigen Capture by Murine Langerhans Cells via the S1P(2) Receptor Subtype}, series = {PLOS ONE}, volume = {7}, journal = {PLOS ONE}, number = {11}, publisher = {PUBLIC LIBRARY SCIENCE}, address = {SAN FRANCISCO}, issn = {1932-6203}, doi = {10.1371/journal.pone.0049427}, pages = {11}, year = {2012}, abstract = {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}, 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} } @article{BhabakKleuserHuwileretal.2013, author = {Bhabak, Krishna P. and Kleuser, Burkhard and Huwiler, Andrea and Arenz, Christoph}, title = {Effective inhibition of acid and neutral ceramidases by novel B-13 and LCL-464 analogues}, series = {Bioorganic \& medicinal chemistry : a Tetrahedron publication for the rapid dissemination of full original research papers and critical reviews on biomolecular chemistry, medicinal chemistry and related disciplines}, volume = {21}, journal = {Bioorganic \& medicinal chemistry : a Tetrahedron publication for the rapid dissemination of full original research papers and critical reviews on biomolecular chemistry, medicinal chemistry and related disciplines}, number = {4}, publisher = {Elsevier}, address = {Oxford}, issn = {0968-0896}, doi = {10.1016/j.bmc.2012.12.014}, pages = {874 -- 882}, year = {2013}, abstract = {Induction of apoptosis mediated by the inhibition of ceramidases has been shown to enhance the efficacy of conventional chemotherapy in several cancer models. Among the inhibitors of ceramidases reported in the literature, B-13 is considered as a lead compound having good in vitro potency towards acid ceramidase. Furthermore, owing to the poor activity of B-13 on lysosoamal acid ceramidase in living cells, LCL-464 a modified derivative of B-13 containing a basic omega-amino group at the fatty acid was reported to have higher potency towards lysosomal acid ceramidase in living cells. In a search for more potent inhibitors of ceramidases, we have designed a series of compounds with structural modifications of B-13 and LCL-464. In this study, we show that the efficacy of B-13 in vitro as well as in intact cells can be enhanced by suitable modification of functional groups. Furthermore, a detailed SAR investigation on LCL-464 analogues revealed novel promising inhibitors of aCDase and nCDase. In cell culture studies using the breast cancer cell line MDA-MB-231, some of the newly developed compounds elevated endogenous ceramide levels and in parallel, also induced apoptotic cell death. In summary, this study shows that structural modification of the known ceramidase inhibitors B-13 and LCL-464 generates more potent ceramidase inhibitors that are active in intact cells and not only elevates the cellular ceramide levels, but also enhances cell death.}, 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{GulbinsPalmadaReicheletal.2013, author = {Gulbins, Erich and Palmada, Monica and Reichel, Martin and Lueth, Anja and Boehmer, Christoph and Amato, Davide and Mueller, Christian P. and Tischbirek, Carsten H. and Groemer, Teja W. and Tabatabai, Ghazaleh and Becker, Katrin Anne and Tripal, Philipp and Staedtler, Sven and Ackermann, Teresa F. and van Brederode, Johannes and Alzheimer, Christian and Weller, Michael and Lang, Undine E. and Kleuser, Burkhard and Grassme, Heike and Kornhuber, Johannes}, title = {Acid sphingomyelinase-ceramide system mediates effects of antidepressant drugs}, series = {Nature medicine}, volume = {19}, journal = {Nature medicine}, number = {7}, publisher = {Nature Publ. Group}, address = {New York}, issn = {1078-8956}, doi = {10.1038/nm.3214}, pages = {934 -- +}, year = {2013}, abstract = {Major depression is a highly prevalent severe mood disorder that is treated with antidepressants. The molecular targets of antidepressants require definition. We investigated the role of the acid sphingomyelinase (Asm)-ceramide system as a target for antidepressants. Therapeutic concentrations of the antidepressants amitriptyline and fluoxetine reduced Asm activity and ceramide concentrations in the hippocampus, increased neuronal proliferation, maturation and survival and improved behavior in mouse models of stress-induced depression. Genetic Asm deficiency abrogated these effects. Mice overexpressing Asm, heterozygous for acid ceramidase, treated with blockers of ceramide metabolism or directly injected with C16 ceramide in the hippocampus had higher ceramide concentrations and lower rates of neuronal proliferation, maturation and survival compared with controls and showed depression-like behavior even in the absence of stress. The decrease of ceramide abundance achieved by antidepressant-mediated inhibition of Asm normalized these effects. Lowering ceramide abundance may thus be a central goal for the future development of antidepressants.}, 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} } @article{PutraNeuberReichetzederetal.2014, author = {Putra, Sulistyo Emantoko Dwi and Neuber, Corinna and Reichetzeder, Christoph and Hocher, Berthold and Kleuser, Burkhard}, title = {Analysis of genomic DNA methylation levels in human placenta using liquid Chromatography-Electrospray ionization tandem mass spectrometry}, series = {Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry and pharmacology}, volume = {33}, journal = {Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry and pharmacology}, number = {4}, publisher = {Karger}, address = {Basel}, issn = {1015-8987}, doi = {10.1159/000358666}, pages = {945 -- 952}, year = {2014}, abstract = {Background: DNA-methylation is a common epigenetic tool which plays a crucial role in gene regulation and is essential for cell differentiation and embryonic development. The placenta is an important organ where gene activity can be regulated by epigenetic DNA modifications, including DNA methylation. This is of interest as, the placenta is the interface between the fetus and its environment, the mother. Exposure to environmental toxins and nutrition during pregnancy may alter DNA methylation of the placenta and subsequently placental function and as a result the phenotype of the offspring. The aim of this study was to develop a reliable method to quantify DNA methylation in large clinical studies. This will be a tool to analyze the degree of DNA methylation in the human placenta in relationship to clinical readouts. Methods: Liquid chromatography-electrospray ionization/multi-stage mass spectrometry (LC-ESI/MS/MS) technique was used for the quantification of the 5dmC/dG ratio in placentas from 248 healthy pregnancies. We were able to demonstrate that this method is a reliable and stable way to determine global placental DNA methylation in large clinical trials. Results/Conclusion: The degree of placental DNA methylation seen in our pilot study varies substantially from 2\% to 5\%. The clinical implications of this variation need to be demonstrated in adequately powered large studies.}, language = {en} } @inproceedings{ArltSchwiebsPfarretal.2014, author = {Arlt, Olga and Schwiebs, Anja and Pfarr, Kathrin and Ranglack, Annika and Bouzas, Ferreiros Nerea and Schreiber, Yannick and Neuber, Corinna and Kleuser, Burkhard and Pfeilschifter, Josef M. and Radeke, Heinfried H.}, title = {Dynamic interaction between sphingolipid enzymes, S1P and inflammatory cytokine regulation in dendritic cells}, series = {NAUNYN-SCHMIEDEBERGS ARCHIVES OF PHARMACOLOGY}, volume = {387}, booktitle = {NAUNYN-SCHMIEDEBERGS ARCHIVES OF PHARMACOLOGY}, publisher = {Springer}, address = {New York}, issn = {0028-1298}, pages = {S91 -- S91}, year = {2014}, language = {en} } @article{ImeriFalleggerZivkovicetal.2014, author = {Imeri, Faik and Fallegger, Daniel and Zivkovic, Aleksandra and Schwalm, Stephanie and Enzmann, Gaby and Blankenbach, Kira and Heringdorf, Dagmar Meyer Zu and Homann, Thomas and Kleuser, Burkhard and Pfeilschifter, Josef and Engelhardt, Britta and Stark, Holger and Huwiler, Andrea}, title = {Novel oxazolo-oxazole derivatives of FTY720 reduce endothelial cell permeability, immune cell chemotaxis and symptoms of experimental autoimmune encephalomyelitis in mice}, series = {Neuropharmacology}, volume = {85}, journal = {Neuropharmacology}, publisher = {Elsevier}, address = {Oxford}, issn = {0028-3908}, doi = {10.1016/j.neuropharm.2014.05.012}, pages = {314 -- 327}, year = {2014}, abstract = {The immunomodulatory FTY720 (fingolimod) is presently approved for the treatment of relapsing-remitting multiple sclerosis. It is a prodrug that acts by modulating sphingosine 1-phosphate (S1P) receptor signaling. In this study, we have developed and characterized two novel oxazolo-oxazole derivatives of FTY720, ST-968 and the oxy analog ST-1071, which require no preceding activating phosphorylation, and proved to be active in intact cells and triggered S1P(1) and S1P(3), but not S1P(2), receptor internalization as a result of receptor activation. Functionally, ST-968 and ST-1071 acted similar to FTY720 to abrogate S1P-triggered chemotaxis of mouse splenocytes, mouse T cells and human U937 cells, and reduced TNFa- and LPS-stimulated endothelial cell permeability. The compounds also reduced TNF alpha-induced ICAM-1 and VCAM-1 mRNA expression, but restored TNF alpha-mediated downregulation of PECAM-1 mRNA expression. In an in vivo setting, the application of ST-968 or ST-1071 to mice resulted in a reduction of blood lymphocytes and significantly reduced the clinical symptoms of experimental autoimmune encephalomyelitis (EAE) in C57BL/6 mice comparable to FTY720 either by prophylactic or therapeutic treatment. In parallel to the reduced clinical symptoms, infiltration of immune cells in the brain was strongly reduced, and in isolated tissues of brain and spinal cord, the mRNA and protein expressions of ICAM-1 and VCAM-1, as well as of matrix metalloproteinase-9 were reduced by all compounds, whereas PECAM-1 and tissue inhibitor of metalloproteinase TIMP-1 were upregulated. In summary, the data suggest that these novel butterfly derivatives of FTY720 could have considerable implication for future therapies of multiple sclerosis and other autoimmune diseases. (C) 2014 Elsevier Ltd. All rights reserved.}, language = {en} } @article{KellerCatalaLehnenHuebneretal.2014, author = {Keller, Johannes and Catala-Lehnen, Philip and Huebner, Antje K. and Jeschke, Anke and Heckt, Timo and Lueth, Anja and Krause, Matthias and Koehne, Till and Albers, Joachim and Schulze, Jochen and Schilling, Sarah and Haberland, Michael and Denninger, Hannah and Neven, Mona and Hermans-Borgmeyer, Irm and Streichert, Thomas and Breer, Stefan and Barvencik, Florian and Levkau, Bodo and Rathkolb, Birgit and Wolf, Eckhard and Calzada-Wack, Julia and Neff, Frauke and Gailus-Durner, Valerie and Fuchs, Helmut and de Angelis, Martin Hrabe and Klutmann, Susanne and Tsourdi, Elena and Hofbauer, Lorenz C. and Kleuser, Burkhard and Chun, Jerold and Schinke, Thorsten and Amling, Michael}, title = {Calcitonin controls bone formation by inhibiting the release of sphingosine 1-phosphate from osteoclasts}, series = {Nature Communications}, volume = {5}, journal = {Nature Communications}, publisher = {Nature Publ. Group}, address = {London}, issn = {2041-1723}, doi = {10.1038/ncomms6215}, pages = {13}, year = {2014}, abstract = {The hormone calcitonin (CT) is primarily known for its pharmacologic action as an inhibitor of bone resorption, yet CT-deficient mice display increased bone formation. These findings raised the question about the underlying cellular and molecular mechanism of CT action. Here we show that either ubiquitous or osteoclast-specific inactivation of the murine CT receptor (CTR) causes increased bone formation. CT negatively regulates the osteoclast expression of Spns2 gene, which encodes a transporter for the signalling lipid sphingosine 1-phosphate (S1P). CTR-deficient mice show increased S1P levels, and their skeletal phenotype is normalized by deletion of the S1P receptor S1P(3). Finally, pharmacologic treatment with the nonselective S1P receptor agonist FTY720 causes increased bone formation in wild-type, but not in S1P(3)-deficient mice. This study redefines the role of CT in skeletal biology, confirms that S1P acts as an osteoanabolic molecule in vivo and provides evidence for a pharmacologically exploitable crosstalk between osteoclasts and osteoblasts.}, language = {en} } @inproceedings{BaranyaiGoedtelArmbrustNestleretal.2014, author = {Baranyai, Dorothea and Goedtel-Armbrust, Ute and Nestler, Sebastian and Kleuser, Burkhard and Wojnowski, Leszek}, title = {A role for cutaneous CYP3A in vitamin D homeostasis?}, series = {NAUNYN-SCHMIEDEBERGS ARCHIVES OF PHARMACOLOGY}, volume = {387}, booktitle = {NAUNYN-SCHMIEDEBERGS ARCHIVES OF PHARMACOLOGY}, publisher = {Springer}, address = {New York}, issn = {0028-1298}, pages = {S27 -- S27}, year = {2014}, language = {en} } @article{SicKrausMadletal.2014, author = {Sic, Heiko and Kraus, Helene and Madl, Josef and Flittner, Karl-Andreas and von Muenchow, Audrey Lilly and Pieper, Kathrin and Rizzi, Marta and Kienzler, Anne-Kathrin and Ayata, Korcan and Rauer, Sebastian and Kleuser, Burkhard and Salzer, Ulrich and Burger, Meike and Zirlik, Katja and Lougaris, Vassilios and Plebani, Alessandro and Roemer, Winfried and Loeffler, Christoph and Scaramuzza, Samantha and Villa, Anna and Noguchi, Emiko and Grimbacher, Bodo and Eibel, Hermann}, title = {Sphingosine-1-phosphate receptors control B-cell migration through signaling components associated with primary immunodeficiencies, chronic lymphocytic leukemia, and multiple sclerosis}, series = {The journal of allergy and clinical immunology}, volume = {134}, journal = {The journal of allergy and clinical immunology}, number = {2}, publisher = {Elsevier}, address = {New York}, issn = {0091-6749}, doi = {10.1016/j.jaci.2014.01.037}, pages = {420 -- +}, year = {2014}, abstract = {Background: Five different G protein-coupled sphingosine-1-phosphate (S1P) receptors (S1P1-S1P5) regulate a variety of physiologic and pathophysiologic processes, including lymphocyte circulation, multiple sclerosis (MS), and cancer. Although B-lymphocyte circulation plays an important role in these processes and is essential for normal immune responses, little is known about S1P receptors in human B cells. Objective: To explore their function and signaling, we studied B-cell lines and primary B cells from control subjects, patients with leukemia, patients with S1P receptor inhibitor-treated MS, and patients with primary immunodeficiencies. Methods: S1P receptor expression was analyzed by using multicolor immunofluorescence microscopy and quantitative PCR. Transwell assays were used to study cell migration. S1P receptor internalization was visualized by means of time-lapse imaging with fluorescent S1P receptor fusion proteins expressed by using lentiviral gene transfer. B-lymphocyte subsets were characterized by means of flow cytometry and immunofluorescence microscopy. Results: Showing that different B-cell populations express different combinations of S1P receptors, we found that S1P1 promotes migration, whereas S1P4 modulates and S1P2 inhibits S1P1 signals. Expression of CD69 in activated B lymphocytes and B cells from patients with chronic lymphocytic leukemia inhibited S1P-induced migration. Studying B-cell lines, normal B lymphocytes, and B cells from patients with primary immunodeficiencies, we identified Bruton tyrosine kinase, beta-arrestin 2, LPS-responsive beige-like anchor protein, dedicator of cytokinesis 8, and Wiskott-Aldrich syndrome protein as critical signaling components downstream of S1P1. Conclusion: Thus S1P receptor signaling regulates human B-cell circulation and might be a factor contributing to the pathology of MS, chronic lymphocytic leukemia, and primary immunodeficiencies.}, language = {en} } @article{PastukhovSchwalmZangemeisterWittkeetal.2014, author = {Pastukhov, Oleksandr and Schwalm, Stephanie and Zangemeister-Wittke, Uwe and Fabbro, Doriano and Bornancin, Frederic and Japtok, Lukasz and Kleuser, Burkhard and Pfeilschifter, Josef and Huwiler, Andrea}, title = {The ceramide kinase inhibitor NVP-231 inhibits breast and lung cancer cell proliferation by inducing M phase arrest and subsequent cell death}, series = {British journal of pharmacology : journal of The British Pharmacological Society}, volume = {171}, journal = {British journal of pharmacology : journal of The British Pharmacological Society}, number = {24}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0007-1188}, doi = {10.1111/bph.12886}, pages = {5829 -- 5844}, year = {2014}, abstract = {Background and PurposeCeramide kinase (CerK) catalyzes the generation of ceramide-1-phosphate which may regulate various cellular functions, including inflammatory reactions and cell growth. Here, we studied the effect of a recently developed CerK inhibitor, NVP-231, on cancer cell proliferation and viability and investigated the role of cell cycle regulators implicated in these responses. Experimental ApproachThe breast and lung cancer cell lines MCF-7 and NCI-H358 were treated with increasing concentrations of NVP-231 and DNA synthesis, colony formation and cell death were determined. Flow cytometry was performed to analyse cell cycle distribution of cells and Western blot analysis was used to detect changes in cell cycle regulator expression and activation. Key ResultsIn both cell lines, NVP-231 concentration-dependently reduced cell viability, DNA synthesis and colony formation. Moreover it induced apoptosis, as measured by increased DNA fragmentation and caspase-3 and caspase-9 cleavage. Cell cycle analysis revealed that NVP-231 decreased the number of cells in S phase and induced M phase arrest with an increased mitotic index, as determined by increased histone H3 phosphorylation. The effect on the cell cycle was even more pronounced when NVP-231 treatment was combined with staurosporine. Finally, overexpression of CerK protected, whereas down-regulation of CerK with siRNA sensitized, cells for staurosporine-induced apoptosis. Conclusions and ImplicationsOur data demonstrate for the first time a crucial role for CerK in the M phase control in cancer cells and suggest its targeted inhibition, using drugs such as NVP-231, in combination with conventional pro-apoptotic chemotherapy.}, language = {en} } @article{PewznerJungTabazavarehGrassmeetal.2014, author = {Pewzner-Jung, Yael and Tabazavareh, Shaghayegh Tavakoli and Grassme, Heike and Becker, Katrin Anne and Japtok, Lukasz and Steinmann, Joerg and Joseph, Tammar and Lang, Stephan and Tuemmler, Burkhard and Schuchman, Edward H. and Lentsch, Alex B. and Kleuser, Burkhard and Edwards, Michael J. and Futerman, Anthony H. and Gulbins, Erich}, title = {Sphingoid long chain bases prevent lung infection by Pseudomonas aeruginosa}, series = {EMBO molecular medicine}, volume = {6}, journal = {EMBO molecular medicine}, number = {9}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {1757-4676}, doi = {10.15252/emmm.201404075}, pages = {1205 -- 1214}, year = {2014}, abstract = {Cystic fibrosis patients and patients with chronic obstructive pulmonary disease, trauma, burn wound, or patients requiring ventilation are susceptible to severe pulmonary infection by Pseudomonas aeruginosa. Physiological innate defense mechanisms against this pathogen, and their alterations in lung diseases, are for the most part unknown. We now demonstrate a role for the sphingoid long chain base, sphingosine, in determining susceptibility to lung infection by P.aeruginosa. Tracheal and bronchial sphingosine levels were significantly reduced in tissues from cystic fibrosis patients and from cystic fibrosis mouse models due to reduced activity of acid ceramidase, which generates sphingosine from ceramide. Inhalation of mice with sphingosine, with a sphingosine analog, FTY720, or with acid ceramidase rescued susceptible mice from infection. Our data suggest that luminal sphingosine in tracheal and bronchial epithelial cells prevents pulmonary P.aeruginosa infection in normal individuals, paving the way for novel therapeutic paradigms based on inhalation of acid ceramidase or of sphingoid long chain bases in lung infection.}, language = {en} } @article{FayyazHenkelJaptoketal.2014, author = {Fayyaz, Susann and Henkel, Janin and Japtok, Lukasz and Kr{\"a}mer, Stephanie and Damm, Georg and Seehofer, Daniel and P{\"u}schel, Gerhard Paul and Kleuser, Burkhard}, title = {Involvement of sphingosine 1-phosphate in palmitate-induced insulin resistance of hepatocytes via the S1P(2) receptor subtype}, series = {Diabetologia : journal of the European Association for the Study of Diabetes (EASD)}, volume = {57}, journal = {Diabetologia : journal of the European Association for the Study of Diabetes (EASD)}, number = {2}, publisher = {Springer}, address = {New York}, issn = {0012-186X}, doi = {10.1007/s00125-013-3123-6}, pages = {373 -- 382}, year = {2014}, abstract = {Enhanced plasma levels of NEFA have been shown to induce hepatic insulin resistance, which contributes to the development of type 2 diabetes. Indeed, sphingolipids can be formed via a de novo pathway from the saturated fatty acid palmitate and the amino acid serine. Besides ceramides, sphingosine 1-phosphate (S1P) has been identified as a major bioactive lipid mediator. Therefore, our aim was to investigate the generation and function of S1P in hepatic insulin resistance. The incorporation of palmitate into sphingolipids was performed by rapid-resolution liquid chromatography-MS/MS in primary human and rat hepatocytes. The influence of S1P and the involvement of S1P receptors in hepatic insulin resistance was examined in human and rat hepatocytes, as well as in New Zealand obese (NZO) mice. Palmitate induced an impressive formation of extra- and intracellular S1P in rat and human hepatocytes. An elevation of hepatic S1P levels was observed in NZO mice fed a high-fat diet. Once generated, S1P was able, similarly to palmitate, to counteract insulin signalling. The inhibitory effect of S1P was abolished in the presence of the S1P(2) receptor antagonist JTE-013 both in vitro and in vivo. In agreement with this, the immunomodulator FTY720-phosphate, which binds to all S1P receptors except S1P(2), was not able to inhibit insulin signalling. These data indicate that palmitate is metabolised by hepatocytes to S1P, which acts via stimulation of the S1P(2) receptor to impair insulin signalling. In particular, S1P(2) inhibition could be considered as a novel therapeutic target for the treatment of insulin resistance.}, language = {en} } @misc{ArltSchwiebsJaptoketal.2014, author = {Arlt, Olga and Schwiebs, Anja and Japtok, Lukasz and Rueger, Katja and Katzy, Elisabeth and Kleuser, Burkhard and Radeke, Heinfried H.}, title = {Sphingosine-1-Phosphate modulates dendritic cell function: focus on non-migratory effects in vitro and in vivo}, series = {Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry and pharmacology}, volume = {34}, journal = {Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry and pharmacology}, number = {1}, publisher = {Karger}, address = {Basel}, issn = {1015-8987}, doi = {10.1159/000362982}, pages = {27 -- 44}, year = {2014}, abstract = {Dendritic cells (DCs) are the cutting edge in innate and adaptive immunity. The major functions of these antigen presenting cells are the capture, endosomal processing and presentation of antigens, providing them an exclusive ability to provoke adaptive immune responses and to induce and control tolerance. Immature DCs capture and process antigens, migrate towards secondary lymphoid organs where they present antigens to naive T cells in a well synchronized sequence of procedures referred to as maturation. Indeed, recent research indicated that sphingolipids are modulators of essential steps in DC homeostasis. It has been recognized that sphingolipids not only modulate the development of DC subtypes from precursor cells but also influence functional activities of DCs such as antigen capture, and cytokine profiling. Thus, it is not astonishing that sphingolipids and sphingolipid metabolism play a substantial role in inflammatory diseases that are modulated by DCs. Here we highlight the function of sphingosine 1-phosphate (S1P) on DC homeostasis and the role of SIP and SW metabolism in inflammatory diseases.}, language = {en} } @misc{FayyazJaptokKleuser2014, author = {Fayyaz, Susann and Japtok, Lukasz and Kleuser, Burkhard}, title = {Divergent role of sphingosine 1-Phosphate on insulin resistance}, series = {Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry and pharmacology}, volume = {34}, journal = {Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry and pharmacology}, number = {1}, publisher = {Karger}, address = {Basel}, issn = {1015-8987}, doi = {10.1159/000362990}, pages = {134 -- 147}, year = {2014}, abstract = {Insulin resistance is a complex metabolic disorder in which insulin-sensitive tissues fail to respond to the physiological action of insulin. There is a strong correlation of insulin resistance and the development of type 2 diabetes both reaching epidemic proportions. Dysfunctional lipid metabolism is a hallmark of insulin resistance and a risk factor for several cardiovascular and metabolic disorders. Numerous studies in humans and rodents have shown that insulin resistance is associated with elevations of non-esterified fatty acids (NEFA) in the plasma. Moreover, bioactive lipid intermediates such as diacylglycerol (DAG) and ceramides appear to accumulate in response to NEFA, which may interact with insulin signaling. However, recent work has also indicated that sphingosine 1-phosphate (S1P), a breakdown product of ceramide, modulate insulin signaling in different cell types. In this review, we summarize the current state of knowledge about S1P and insulin signaling in insulin sensitive cells. A specific focus is put on the action of S1P on hepatocytes, pancreatic beta-cells and skeletal muscle cells. In particular, modulation of S1P-signaling can be considered as a potential therapeutic target for the treatment of insulin resistance and type 2 diabetes.}, language = {en} } @article{NeuberSchumacherGulbinsetal.2014, author = {Neuber, Corinna and Schumacher, Fabian and Gulbins, Erich and Kleuser, Burkhard}, title = {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}, series = {Analytical chemistry}, volume = {86}, journal = {Analytical chemistry}, number = {18}, publisher = {American Chemical Society}, address = {Washington}, issn = {0003-2700}, doi = {10.1021/ac501677y}, pages = {9065 -- 9073}, year = {2014}, abstract = {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 Sjogren-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 chromatographyelectrospray ionizationquadrupole/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 Sjogren-Larsson syndrome, in more detail.}, language = {en} } @article{GereckeScholtkaLoewensteinetal.2015, author = {Gerecke, Christian and Scholtka, Bettina and Loewenstein, Yvonne and Fait, Isabel and Gottschalk, Uwe and Rogoll, Dorothee and Melcher, Ralph and Kleuser, Burkhard}, title = {Hypermethylation of ITGA4, TFPI2 and VIMENTIN promoters is increased in inflamed colon tissue: putative risk markers for colitis-associated cancer}, series = {Journal of cancer research and clinical oncology : official organ of the Deutsche Krebsgesellschaft}, volume = {141}, journal = {Journal of cancer research and clinical oncology : official organ of the Deutsche Krebsgesellschaft}, number = {12}, publisher = {Springer}, address = {New York}, issn = {0171-5216}, doi = {10.1007/s00432-015-1972-8}, pages = {2097 -- 2107}, year = {2015}, abstract = {Epigenetic silencing of tumor suppressor genes is involved in early transforming events and has a high impact on colorectal carcinogenesis. Likewise, colon cancers that derive from chronically inflamed bowel diseases frequently exhibit epigenetic changes. But there is little data about epigenetic aberrations causing colorectal cancer in chronically inflamed tissue. The aim of the present study was to evaluate the aberrant gain of methylation in the gene promoters of VIM, TFPI2 and ITGA4 as putative early markers in the development from inflamed tissue via precancerous lesions toward colorectal cancer. Initial screening of different cancer cell lines by using methylation-specific PCR revealed a putative colon cancer-specific methylation pattern. Additionally, a demethylation assay was performed to investigate the methylation-dependent gene silencing of ITGA4. The candidate markers were analyzed in colonic tissue specimens from patients with colorectal cancer (n = 15), adenomas (n = 76), serrated lesions (n = 13), chronic inflammation (n = 10) and normal mucosal samples (n = 9). A high methylation frequency of VIM (55.6 \%) was observed in normal colon tissue, whereas ITGA4 and TFPI2 were completely unmethylated in controls. A significant gain of methylation frequency with progression of disease as well as an age-dependent effect was detectable for TFPI2. ITGA4 methylation frequency was high in precancerous and cancerous tissues as well as in inflammatory bowel diseases (IBD). The already established methylation marker VIM does not permit a specific and sensitive discrimination of healthy and neoplastic tissue. The methylation markers ITGA4 and TFPI2 seem to be suitable risk markers for inflammation-associated colon cancer.}, language = {en} } @article{SchraplauScheweNeuschaeferRubeetal.2015, author = {Schraplau, Anne and Schewe, Bettina and Neusch{\"a}fer-Rube, Frank and Ringel, Sebastian and Neuber, Corinna and Kleuser, Burkhard and P{\"u}schel, Gerhard Paul}, title = {Enhanced thyroid hormone breakdown in hepatocytes by mutual induction of the constitutive androstane receptor (CAR, NR1I3) and arylhydrocarbon receptor by benzo[a]pyrene and phenobarbital}, series = {Toxicology}, volume = {328}, journal = {Toxicology}, publisher = {Elsevier}, address = {Clare}, issn = {0300-483X}, doi = {10.1016/j.tox.2014.12.004}, pages = {21 -- 28}, year = {2015}, abstract = {Xenobiotics may interfere with the hypothalamic-pituitary-thyroid endocrine axis by inducing enzymes that inactivate thyroid hormones and thereby reduce the metabolic rate. This induction results from an activation of xeno-sensing nuclear receptors. The current study shows that benzo[a]pyrene, a frequent contaminant of processed food and activator of the arylhydrocarbon receptor (AhR) activated the promoter and induced the transcription of the nuclear receptor constitutive androstane receptor (CAR, NR1I3) in rat hepatocytes. Likewise, phenobarbital induced the AhR transcription. This mutual induction of the nuclear receptors enhanced the phenobarbital-dependent induction of the prototypic CAR target gene Cyp2b1 as well as the AhR-dependent induction of UDP-glucuronosyltransferases. In both cases, the induction by the combination of both xenobiotics was more than the sum of the induction by either substance alone. By inducing the AhR, phenobarbital enhanced the benzo[a]pyrene-dependent reduction of thyroid hormone half-life and the benzo[a]pyrene-dependent increase in the rate of thyroid hormone glucuronide formation in hepatocyte cultures. CAR ligands might thus augment the endocrine disrupting potential of AhR activators by an induction of the AhR. (C) 2014 Elsevier Ireland Ltd. All rights reserved.}, language = {en} } @misc{PrueferKleuservanderGiet2015, author = {Pr{\"u}fer, Nicole and Kleuser, Burkhard and van der Giet, Markus}, title = {The role of serum amyloid A and sphingosine-1-phosphate on high-density lipoprotein functionality}, series = {Biological chemistry}, volume = {396}, journal = {Biological chemistry}, number = {6-7}, publisher = {De Gruyter}, address = {Berlin}, issn = {1431-6730}, doi = {10.1515/hsz-2014-0192}, pages = {573 -- 583}, year = {2015}, abstract = {The high-density lipoprotein (HDL) is one of the most important endogenous cardiovascular protective markers. HDL is an attractive target in the search for new pharmaceutical therapies and in the prevention of cardiovascular events. Some of HDL's anti-atherogenic properties are related to the signaling molecule sphingosine-1-phosphate (S1P), which plays an important role in vascular homeostasis. However, for different patient populations it seems more complicated. Significant changes in HDL's protective potency are reduced under pathologic conditions and HDL might even serve as a proatherogenic particle. Under uremic conditions especially there is a change in the compounds associated with HDL. S1P is reduced and acute phase proteins such as serum amyloid A (SAA) are found to be elevated in HDL. The conversion of HDL in inflammation changes the functional properties of HDL. High amounts of SAA are associated with the occurrence of cardiovascular diseases such as atherosclerosis. SAA has potent pro-atherogenic properties, which may have impact on HDL's biological functions, including cholesterol efflux capacity, antioxidative and anti-inflammatory activities. This review focuses on two molecules that affect the functionality of HDL. The balance between functional and dysfunctional HDL is disturbed after the loss of the protective sphingolipid molecule S1P and the accumulation of the acute-phase protein SAA. This review also summarizes the biological activities of lipid-free and lipid-bound SAA and its impact on HDL function.}, language = {en} } @inproceedings{FrombachRancanFleigeetal.2015, author = {Frombach, Janna and Rancan, Fiorenza and Fleige, Emanuel and Haag, Rainer and Schumacher, Frank and Kleuser, Burkhard and Yamamoto, Kenji and R{\"u}hl, Eckart and Blume-Peytavi, Ulrike and Vogt, Annika}, title = {Skin penetration and dexamethasone release from polymer nanoparticles in ex vivo human skin}, series = {The journal of investigative dermatology}, volume = {135}, booktitle = {The journal of investigative dermatology}, publisher = {Nature Publ. Group}, address = {New York}, issn = {0022-202X}, pages = {S52 -- S52}, year = {2015}, language = {en} } @article{ReichelHoenigLiebischetal.2015, author = {Reichel, Martin and Hoenig, Stefanie and Liebisch, Gerhard and L{\"u}th, Anja and Kleuser, Burkhard and Gulbins, Erich and Schmitz, Gerd and Kornhuber, Johannes}, title = {Alterations of plasma glycerophospholipid and sphingolipid species in male alcohol-dependent patients}, series = {Biochimica et biophysica acta : Molecular and cell biology of lipids}, volume = {1851}, journal = {Biochimica et biophysica acta : Molecular and cell biology of lipids}, number = {11}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1388-1981}, doi = {10.1016/j.bbalip.2015.08.005}, pages = {1501 -- 1510}, year = {2015}, abstract = {Background: Alcohol abuse is a major risk factor for somatic and neuropsychiatric diseases. Despite their potential clinical importance, little is known about the alterations of plasma glycerophospholipid (GPL) and sphingolipid (SPL) species associated with alcohol abuse. Methods: Plasma GPL and SPL species were quantified using electrospray ionization tandem mass spectrometry in samples from 23 male alcohol-dependent patients before and after detoxification, as well as from 20 healthy male controls. Results: A comparison of alcohol-dependent patients with controls revealed higher phosphatidylcholine (PC; P-value = 0.008) and phosphatidylinositol (PI; P-value = 0.001) concentrations in patients before detoxification, and higher PI (P-value = 0.001) and phosphatidylethanolamine (PE)-based plasmalogen (PEP; P-value = 0.003) concentrations after detoxification. Lysophosphatidylcholines (LPC) were increased by acute intoxication (P-value = 0.002). Sphingomyelin (SM) concentration increased during detoxification (P-value = 0.011). The concentration of SM 23:0 was lower in patients (P-value = 2.79 x 10(-5)), and the concentrations of ceramide Cer d18:1/16:0 and Cer d18:1/18:0 were higher in patients (P-value = 2.45 x 10(-5) and 3.73 x 10(-5)). Activity of lysosomal acid sphingomyelinase (ASM) in patients correlated positively with the concentrations of eight LPC species, while activity of secreted ASM was inversely correlated with several PE, PI and PC species, and positively correlated with the molar ratio of PC to SM (Pearson's r = 0.432; P-value = 0.039). Conclusion: Plasma concentrations of numerous GPL and SPL species were altered in alcohol-dependent patients. These molecules might serve as potential biomarkers to improve the diagnosis of patients and to indicate health risks associated with alcohol abuse. Our study further indicates that there are strong interactions between plasma GPL concentrations and SPL metabolism. (C) 2015 Elsevier B.V. All rights reserved.}, language = {en} } @article{HenryNeillBeckeretal.2015, author = {Henry, Brian D. and Neill, Daniel R. and Becker, Katrin Anne and Gore, Suzanna and Bricio-Moreno, Laura and Ziobro, Regan and Edwards, Michael J. and Muehlemann, Kathrin and Steinmann, Joerg and Kleuser, Burkhard and Japtok, Lukasz and Luginbuehl, Miriam and Wolfmeier, Heidi and Scherag, Andre and Gulbins, Erich and Kadioglu, Aras and Draeger, Annette and Babiychuk, Eduard B.}, title = {Engineered liposomes sequester bacterial exotoxins and protect from severe invasive infections in mice}, series = {Nature biotechnology : the science and business of biotechnology}, volume = {33}, journal = {Nature biotechnology : the science and business of biotechnology}, number = {1}, publisher = {Nature Publ. Group}, address = {New York}, issn = {1087-0156}, doi = {10.1038/nbt.3037}, pages = {81 -- U295}, year = {2015}, abstract = {Gram-positive bacterial pathogens that secrete cytotoxic pore-forming toxins, such as Staphylococcus aureus and Streptococcus pneumoniae, cause a substantial burden of disease. Inspired by the principles that govern natural toxin-host interactions, we have engineered artificial liposomes that are tailored to effectively compete with host cells for toxin binding. Liposome-bound toxins are unable to lyse mammalian cells in vitro. We use these artificial liposomes as decoy targets to sequester bacterial toxins that are produced during active infection in vivo. Administration of artificial liposomes within 10 h after infection rescues mice from septicemia caused by S. aureus and S. pneumoniae, whereas untreated mice die within 24-33 h. Furthermore, liposomes protect mice against invasive pneumococcal pneumonia. Composed exclusively of naturally occurring lipids, tailored liposomes are not bactericidal and could be used therapeutically either alone or in conjunction with antibiotics to combat bacterial infections and to minimize toxin-induced tissue damage that occurs during bacterial clearance.}, language = {en} } @article{JaptokSchmitzFayyazetal.2015, author = {Japtok, Lukasz and Schmitz, Elisabeth I. and Fayyaz, Susann and Kr{\"a}mer, Stephanie and Hsu, Leigh J. and Kleuser, Burkhard}, title = {Sphingosine 1-phosphate counteracts insulin signaling in pancreatic beta-cells via the sphingosine 1-phosphate receptor subtype 2}, series = {The FASEB journal : the official journal of the Federation of American Societies for Experimental Biology}, volume = {29}, journal = {The FASEB journal : the official journal of the Federation of American Societies for Experimental Biology}, number = {8}, publisher = {Federation of American Societies for Experimental Biology}, address = {Bethesda}, issn = {0892-6638}, doi = {10.1096/fj.14-263194}, pages = {3357 -- 3369}, year = {2015}, abstract = {Glucolipotoxic stress has been identified as a key player in the progression of pancreatic beta-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 beta-cells but also regulate beta-cell homeostasis in a divergent manner. Although S1P possesses a prosurvival effect in beta-cells, an enhanced level of the sphingolipid antagonizes insulin-mediated cell growth and survival via the sphingosine 1-phosphate receptor subtype 2 (S1P(2)) followed by an inhibition of Akt-signaling. In an attempt to investigate the role of the S1P/S1P(2) axis in vivo, the New Zealand obese (NZO) diabetic mouse model, characterized by beta-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 S1P(2), the receptor antagonist JTE-013 was administered. Most interestingly, JTE-013 rescued beta-cell damage clearly indicating an important role of the S1P(2) in beta-cell homeostasis. Therefore, the present study provides a new therapeutic strategy to diminish beta-cell dysfunction and the development of T2D.}, language = {en} } @article{MichelsJaptokAlisjahbanaetal.2015, author = {Michels, Meta and Japtok, Lukasz and Alisjahbana, Bachti and Wisaksana, Rudi and Sumardi, Uun and Puspita, Mita and Kleuser, Burkhard and de Mast, Quirijn and van der Ven, Andre J. A. M.}, title = {Decreased plasma levels of the endothelial protective sphingosine-1-phosphate are associated with dengue-induced plasma leakage}, series = {Journal of infection}, volume = {71}, journal = {Journal of infection}, number = {4}, publisher = {Elsevier}, address = {London}, issn = {0163-4453}, doi = {10.1016/j.jinf.2015.06.014}, pages = {480 -- 487}, year = {2015}, abstract = {Background: A transient endothelial hyperpermeability is a hallmark of severe dengue infections. Sphingosine-1-phosphate (S1P) maintains vascular integrity and protects against plasma leakage. We related plasma S1P levels to dengue-induced plasma leakage and studied mechanisms that may underlie the decrease in S1P levels in dengue. Methods: We determined circulating levels of S1P in 44 Indonesian adults with acute dengue and related levels to plasma leakage, as determined by daily ultrasonography, and to levels of its chaperone apolipoprotein M, other lipoproteins and platelets. Results: Plasma S1P levels were decreased during dengue and patients with plasma leakage had lower median levels compared to those without (638 vs. 745 nM; p < 0.01). ApoM and other lipoprotein levels were also decreased during dengue, but did not correlate to S1P levels. Platelet counts correlated positively with S1P levels, but S1P levels were not higher in frozen-thawed platelet rich plasma, arguing against platelets as an important cellular source of S1P in dengue. Conclusions: Decreased plasma S1P levels during dengue are associated with plasma leakage. We speculate that decreased levels of ApoM underlies the lower S1P levels. Modulation of S1P levels and its receptors may be a novel therapeutic intervention to prevent plasma leakage in dengue. (C) 2015 The British Infection Association. Published by Elsevier Ltd. All rights reserved.}, language = {en} } @article{CarpinteiroBeckerJaptoketal.2015, author = {Carpinteiro, Alexander and Becker, Katrin Anne and Japtok, Lukasz and Hessler, Gabriele and Keitsch, Simone and Pozgajova, Miroslava and Schmid, Kurt W. and Adams, Constantin and M{\"u}ller, Stefan and Kleuser, Burkhard and Edwards, Michael J. and Grassme, Heike and Helfrich, Iris and Gulbins, Erich}, title = {Regulation of hematogenous tumor metastasis by acid sphingomyelinase}, series = {EMBO molecular medicine}, volume = {7}, journal = {EMBO molecular medicine}, number = {6}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {1757-4676}, pages = {714 -- 734}, year = {2015}, abstract = {Metastatic dissemination of cancer cells is the ultimate hallmark of malignancy and accounts for approximately 90\% of human cancer deaths. We investigated the role of acid sphingomyelinase (Asm) in the hematogenous metastasis of melanoma cells. Intravenous injection of B16F10 melanoma cells into wild-type mice resulted in multiple lung metastases, while Asm-deficient mice (Smpd1(-/-) mice) were protected from pulmonary tumor spread. Transplanting wild-type platelets into Asm-deficient mice reinstated tumor metastasis. Likewise, Asm-deficient mice were protected from hematogenous MT/ret melanoma metastasis to the spleen in a mouse model of spontaneous tumor metastasis. Human and mouse melanoma cells triggered activation and release of platelet secretory Asm, in turn leading to ceramide formation, clustering, and activation of 51 integrins on melanoma cells finally leading to adhesion of the tumor cells. Clustering of integrins by applying purified Asm or C-16 ceramide to B16F10 melanoma cells before intravenous injection restored trapping of tumor cells in the lung in Asm-deficient mice. This effect was revertable by arginine-glycine-aspartic acid peptides, which are known inhibitors of integrins, and by antibodies neutralizing 1 integrins. These findings indicate that melanoma cells employ platelet-derived Asm for adhesion and metastasis.}, language = {en} } @article{ChakrabortyChenBornhorstetal.2015, author = {Chakraborty, Sudipta and Chen, Pan and Bornhorst, Julia and Schwerdtle, Tanja and Schumacher, Fabian and Kleuser, Burkhard and Bowman, Aaron B. and Aschner, Michael A.}, title = {Loss of pdr-1/parkin influences Mn homeostasis through altered ferroportin expression in C-elegans}, series = {Metallomics : integrated biometal science}, volume = {7}, journal = {Metallomics : integrated biometal science}, number = {5}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1756-5901}, doi = {10.1039/c5mt00052a}, pages = {847 -- 856}, year = {2015}, language = {en} } @article{SchumacherChakrabortyKleuseretal.2015, author = {Schumacher, Fabian and Chakraborty, Sudipta and Kleuser, Burkhard and Gulbins, Erich and Schwerdtle, Tanja and Aschner, Michael A. and Bornhorst, Julia}, title = {Highly sensitive isotope-dilution liquid-chromatography-electrospray ionization-tandem-mass spectrometry approach to study the drug-mediated modulation of dopamine and serotonin levels in Caenorhabditis elegans}, series = {Talanta : the international journal of pure and applied analytical chemistry}, volume = {144}, journal = {Talanta : the international journal of pure and applied analytical chemistry}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0039-9140}, doi = {10.1016/j.talanta.2015.05.057}, pages = {71 -- 79}, year = {2015}, abstract = {Dopamine (DA) and serotonin (SRT) are monoamine neurotransmitters that play a key role in regulating the central and peripheral nervous system. Their impaired metabolism has been implicated in several neurological disorders, such as Parkinson's disease and depression. Consequently, it is imperative to monitor changes in levels of these low-abundant neurotransmitters and their role in mediating disease. For the first time, a rapid, specific and sensitive isotope-dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of DA and SRT in the nematode Caenorhabditis elegans (C. elegans). This model organism offers a unique approach for studying the effect of various drugs and environmental conditions on neurotransmitter levels, given by the conserved DA and SRT biology, including synaptic release, trafficking and formation. We introduce a novel sample preparation protocol incorporating the usage of sodium thiosulfate in perchloric acid as extraction medium that assures high recovery of the relatively unstable neurotransmitters monitored. Moreover, the use of both deuterated internal standards and the multiple reaction monitoring (MRM) technique allows for unequivocal quantification. Thereby, to the best of our knowledge, we achieve a detection sensitivity that clearly exceeds those of published DA and SRT quantification methods in various matrices. We are the first to show that exposure of C elegans to the monoamine oxidase B (MAOB) inhibitor selegiline or the catechol-O-methyltransferase (COMT) inhibitor tolcapone, in order to block DA and SRT degradation, resulted in accumulation of the respective neurotransmitter. Assessment of a behavioral output of the dopaminergic system (basal slowing response) corroborated the analytical LC-MS/MS data. Thus, utilization of the C elegans model system in conjunction with our analytical method is well-suited to investigate drug-mediated modulation of the DA and SRT system in order to identify compounds with neuroprotective or regenerative properties. (C) 2015 Elsevier B.V. All rights reserved.}, language = {en} } @article{EdlichGereckeGiulbudagianetal.2016, author = {Edlich, Alexander and Gerecke, Christian and Giulbudagian, Michael and Neumann, Falko and Hedtrich, Sarah and Schaefer-Korting, Monika and Ma, Nan and Calderon, Marcelo and Kleuser, Burkhard}, title = {Specific uptake mechanisms of well-tolerated thermoresponsive polyglycerol-based nanogels in antigen-presenting cells of the skin}, series = {European Journal of Pharmaceutics and Biopharmaceutics}, volume = {116}, journal = {European Journal of Pharmaceutics and Biopharmaceutics}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0939-6411}, doi = {10.1016/j.ejpb.2016.12.016}, pages = {155 -- 163}, year = {2016}, abstract = {Engineered nanogels are of high value for a targeted and controlled transport of compounds due to the ability to change their chemical properties by external stimuli. As it has been indicated that nanogels possess a high ability to penetrate the stratum corneum, it cannot be excluded that nanogels interact with dermal dendritic cells, especially in diseased skin. In this study the potential crosstalk of the thermore-sponsive nanogels (tNGs) with the dendritic cells of the skin was investigated with the aim to determine the immunotoxicological properties of the nanogels. The investigated tNGs were made of dendritic polyglycerol (dPG) and poly(glycidyl methyl ether-co-ethyl glycidyl ether) (p(GME-co-EGE)), as polymer conferring thermoresponsive properties. Although the tNGs were taken up, they displayed neither cytotoxic and genotoxic effects nor any induction of reactive oxygen species in the tested cells. Interestingly, specific uptake mechanisms of the tNGs by the dendritic cells were depending on the nanogels cloud point temperature (Tcp), which determines the phase transition of the nanoparticle. The study points to caveolae-mediated endocytosis as being the major tNGs uptake mechanism at 37 degrees C, which is above the Tcp of the tNGs. Remarkably, an additional uptake mechanism, beside caveolae-mediated endocytosis, was observed at 29 degrees C, which is the Tcp of the tNGs. At this temperature, which is characterized by two different states of the tNGs, macropinocytosis was involved as well. In summary, our study highlights the impact of thermoresponsivity on the cellular uptake mechanisms which has to be taken into account if the tNGs are used as a drug delivery system.}, language = {en} } @article{ReichetzederPutraPfabetal.2016, author = {Reichetzeder, Christoph and Putra, S. E. Dwi and Pfab, T. and Slowinski, T. and Neuber, Corinna and Kleuser, Burkhard and Hocher, Berthold}, title = {Increased global placental DNA methylation levels are associated with gestational diabetes}, series = {Clinical epigenetics}, volume = {8}, journal = {Clinical epigenetics}, publisher = {BioMed Central}, address = {London}, issn = {1868-7083}, doi = {10.1186/s13148-016-0247-9}, pages = {10}, year = {2016}, abstract = {Background: Gestational diabetes mellitus (GDM) is associated with adverse pregnancy outcomes. It is known that GDM is associated with an altered placental function and changes in placental gene regulation. More recent studies demonstrated an involvement of epigenetic mechanisms. So far, the focus regarding placental epigenetic changes in GDM was set on gene-specific DNA methylation analyses. Studies that robustly investigated placental global DNA methylation are lacking. However, several studies showed that tissue-specific alterations in global DNA methylation are independently associated with type 2 diabetes. Thus, the aim of this study was to characterize global placental DNA methylation by robustly measuring placental DNA 5-methylcytosine (5mC) content and to examine whether differences in placental global DNA methylation are associated with GDM. Methods: Global DNA methylation was quantified by the current gold standard method, LC-MS/MS. In total, 1030 placental samples were analyzed in this single-center birth cohort study. Results: Mothers with GDM displayed a significantly increased global placental DNA methylation (3.22 +/- 0.63 vs. 3.00 +/- 0.46 \%; p = 0.013; +/- SD). Bivariate logistic regression showed a highly significant positive correlation between global placental DNA methylation and the presence of GDM (p = 0.0009). Quintile stratification according to placental DNA 5mC levels revealed that the frequency of GDM was evenly distributed in quintiles 1-4 (2.9-5.3 \%), whereas the frequency in the fifth quintile was significantly higher (10.7 \%; p = 0.003). Bivariate logistic models adjusted for maternal age, BMI, ethnicity, recurrent miscarriages, and familiar diabetes predisposition clearly demonstrated an independent association between global placental DNA hypermethylation and GDM. Furthermore, an ANCOVA model considering known predictors of DNA methylation substantiated an independent association between GDM and placental DNA methylation. Conclusions: This is the first study that employed a robust quantitative assessment of placental global DNA methylation in over a thousand placental samples. The study provides large scale evidence that placental global DNA hypermethylation is associated with GDM, independent of established risk factors.}, language = {en} } @article{LiLuReichetzederetal.2016, author = {Li, Jian and Lu, Yong Ping and Reichetzeder, Christoph and Kalk, Philipp and Kleuser, Burkhard and Adamski, Jerzy and Hocher, Berthold}, title = {Maternal PCaaC38:6 is Associated With Preterm Birth - a Risk Factor for Early and Late Adverse Outcome of the Offspring}, series = {Journal of European public policy}, volume = {41}, journal = {Journal of European public policy}, publisher = {Karger}, address = {Basel}, issn = {1420-4096}, doi = {10.1159/000443428}, pages = {250 -- 257}, year = {2016}, abstract = {Background/Aims: Preterm birth (PTB) and low birth weight (LBW) significantly influence mortality and morbidity of the offspring in early life and also have long-term consequences in later life. A better understanding of the molecular mechanisms of preterm birth could provide new insights regarding putative preventive strategies. Metabolomics provides a powerful analytic tool to readout complex interactions between genetics, environment and health and may serve to identify relevant biomarkers. In this study, the association between 163 targeted maternal blood metabolites and gestational age was investigated in order to find candidate biomarkers for PTB. Methods: Five hundred twenty-three women were included into this observational study. Maternal blood was obtained before delivery. The concentration of 163 maternal serum metabolites was measured by flow injection tandem mass spectrometry. To find putative biomarkers for preterm birth, a three-step analysis was designed: bivariate correlation analysis followed by multivariable regression analysis and a comparison of mean values among gestational age groups. Results: Bivariate correlation analysis showed that 2 acylcarnitines (C16:2, C2), 1 amino acids (xLeu), 8 diacyl-PCs (PCaaC36:4, PCaaC38:4, PCaaC38:5, PCaaC38:6, PCaaC40:4, PCaaC40:5, PCaaC40:6, PCaaC42:4), and 1 Acylalkyl-PCs (PCaeC40:5) were inversely correlated with gestational age. Multivariable regression analysis confounded for PTB history, maternal body mass index (BMI) before pregnancy, systolic blood pressure at the third trimester, and maternal body weight at the third trimester, showed that the diacyl-PC PCaaC38:6 was the only metabolite inversely correlated with gestational age. Conclusions: Maternal blood concentrations of PCaaC38:6 are independently associated with gestational age. (C) 2016 The Author(s) Published by S. Karger AG, Basel}, language = {en} } @article{AhlbergRancanEppleetal.2016, author = {Ahlberg, Sebastian and Rancan, Fiorenza and Epple, Matthias and Loza, Kateryna and H{\"o}ppe, David and Lademann, J{\"u}rgen and Vogt, Annika and Kleuser, Burkhard and Gerecke, Christian and Meinke, Martina C.}, title = {Comparison of different methods to study effects of silver nanoparticles on the pro- and antioxidant status of human keratinocytes and fibroblasts}, series = {Methods : focusing on rapidly developing techniques}, volume = {109}, journal = {Methods : focusing on rapidly developing techniques}, publisher = {Elsevier}, address = {San Diego}, issn = {1046-2023}, doi = {10.1016/j.ymeth.2016.05.015}, pages = {55 -- 63}, year = {2016}, language = {en} } @article{HoenzkeGereckeElpeltetal.2016, author = {H{\"o}nzke, Stefan and Gerecke, Christian and Elpelt, Anja and Zhang, Nan and Unbehauen, Michael and Kral, Vivian and Fleige, Emanuel and Paulus, Florian and Haag, Rainer and Sch{\"a}fer-Korting, Monika and Kleuser, Burkhard and Hedtrich, Sarah}, title = {Tailored dendritic core-multishell nanocarriers for efficient dermal drug delivery: A systematic top-down approach from synthesis to preclinical testing}, series = {Journal of controlled release}, volume = {242}, journal = {Journal of controlled release}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0168-3659}, doi = {10.1016/j.jconrel.2016.06.030}, pages = {50 -- 63}, year = {2016}, abstract = {Drug loaded dendritic core-multishell (CMS) nanocarriers are of especial interest for the treatment of skin diseases, owing to their striking dermal delivery efficiencies following topical applications. CMS nanocarriers are composed of a polyglycerol core, connected by amide-bonds to an inner alkyl shell and an outer methoxy poly(ethylene glycol) shell. Since topically applied nanocarriers are subjected to biodegradation, the application of conventional amide-based CMS nanocarriers (10-A-18-350) has been limited by the potential production of toxic polyglycerol amines. To circumvent this issue, three tailored ester-based CMS nanocarriers (10-E-12-350, 10-E-15-350, 10-E-18-350) of varying inner alkyl chain length were synthesized and comprehensively characterized in terms of particle size, drug loading, biodegradation and dermal drug delivery efficiency. Dexamethasone (DXM), a potent drug widely used for the treatment of inflammatory skin diseases, was chosen as a therapeutically relevant test compound for the present study. Ester-and amide-based CMS nanocarriers delivered DXM more efficiently into human skin than a commercially available DXM cream. Subsequent in vitro and in vivo toxicity studies identified CMS (10-E-15-350) as the most biocompatible carrier system. The anti-inflammatory potency of DXM-loaded CMS (10-E-15-350) nanocarriers was assessed in TNF alpha supplemented skin models, where a significant reduction of the pro-inflammatory cytokine IL-8 was seen, with markedly greater efficacy than commercial DXM cream. In summary, we report the rational design and characterization of tailored, biodegradable, ester-based CMS nanocarriers, and their subsequent stepwise screening for biocompatibility, dermal delivery efficiency and therapeutic efficacy in a top-down approach yielding the best carrier system for topical applications. (C) 2016 Elsevier B.V. All rights reserved.}, language = {en} } @article{SahleBalzusGereckeetal.2016, author = {Sahle, Fitsum Feleke and Balzus, Benjamin and Gerecke, Christian and Kleuser, Burkhard and Bodmeier, Roland}, title = {Formulation and in vitro evaluation of polymeric enteric nanoparticles as dermal carriers with pH-dependent targeting potential}, series = {European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences, EUFEPS}, volume = {92}, journal = {European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences, EUFEPS}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0928-0987}, doi = {10.1016/j.ejps.2016.07.004}, pages = {98 -- 109}, year = {2016}, abstract = {pH-sensitive nanoparticles which release in a controlled fashion on the skin or dissolve in the hair follicle could significantly improve treatment effectiveness and make transfollicular drug delivery a success. Dexamethasone-loaded Eudragit L 100 nanoparticles were prepared by nanoprecipitation from an organic drug-polymer solution. Their toxicity potential was assessed using isolated human fibroblasts. pH-dependent swelling and erosion kinetics of the nanoparticles were investigated by dynamic light scattering and viscosity measurements and its effect on drug release was assessed in vitro with Franz diffusion cells. Stable, 100-550 nm-sized dexamethasone-loaded Eudragit L 100 nanoparticles with drug loading capacity and entrapment efficiency as high as 83\% and 85\%, respectively, were obtained by using polyvinyl alcohol as a stabilizer and ethanol as organic solvent The nanoparticles showed little or no toxicity on isolated normal human fibroblasts. Dexamethasone existed in the nanoparticles as solid solution or in amorphous form. The nanoparticles underwent extensive swelling and slow drug release in media with a low buffer capacity (as low as 10 mM) and a higher pH or at a pH close to the dissolution pH of the polymer (pH 6) and a higher buffer capacity. In 40 mM buffer and above pH 6.8, the nanoparticles eroded fast or dissolved completely and thus released the drug rapidly. pH-sensitive nanoparticles which potentially release in a controlled manner on the stratum corneum but dissolve in the hair follicle could be prepared. (C) 2016 Elsevier B.V. All rights reserved.}, language = {en} } @article{HustonKornhuberMuehleetal.2016, author = {Huston, Joseph P. and Kornhuber, Johannes and Muehle, Christiane and Japtok, Lukasz and Komorowski, Mara and Mattern, Claudia and Reichel, Martin and Gulbins, Erich and Kleuser, Burkhard and Topic, Bianca and Silva, Maria A. De Souza and Mueller, Christian P.}, title = {A sphingolipid mechanism for behavioral extinction}, series = {Journal of neurochemistry}, volume = {137}, journal = {Journal of neurochemistry}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0022-3042}, doi = {10.1111/jnc.13537}, pages = {589 -- 603}, year = {2016}, abstract = {Reward-dependent instrumental behavior must continuously be re-adjusted according to environmental conditions. Failure to adapt to changes in reward contingencies may incur psychiatric disorders like anxiety and depression. When an expected reward is omitted, behavior undergoes extinction. While extinction involves active re-learning, it is also accompanied by emotional behaviors indicative of frustration, anxiety, and despair (extinction-induced depression). Here, we report evidence for a sphingolipid mechanism in the extinction of behavior. Rapid extinction, indicating efficient re-learning, coincided with a decrease in the activity of the enzyme acid sphingomyelinase (ASM), which catalyzes turnover of sphingomyelin to ceramide, in the dorsal hippocampus of rats. The stronger the decline in ASM activity, the more rapid was the extinction. Sphingolipid-focused lipidomic analysis showed that this results in a decline of local ceramide species in the dorsal hippocampus. Ceramides shape the fluidity of lipid rafts in synaptic membranes and by that way can control neural plasticity. We also found that aging modifies activity of enzymes and ceramide levels in selective brain regions. Aging also changed how the chronic treatment with corticosterone (stress) or intranasal dopamine modified regional enzyme activity and ceramide levels, coinciding with rate of extinction. These data provide first evidence for a functional ASM-ceramide pathway in the brain involved in the extinction of learned behavior. This finding extends the known cellular mechanisms underlying behavioral plasticity to a new class of membrane-located molecules, the sphingolipids, and their regulatory enzymes, and may offer new treatment targets for extinction- and learning-related psychopathological conditions.}, language = {en} } @article{HollmannWernerAvotaetal.2016, author = {Hollmann, Claudia and Werner, Sandra and Avota, Elita and Reuter, Dajana and Japtok, Lukasz and Kleuser, Burkhard and Gulbins, Erich and Becker, Katrin Anne and Schneider-Schaulies, J{\"u}rgen and Beyersdorf, Niklas}, title = {Inhibition of Acid Sphingomyelinase Allows for Selective Targeting of CD4(+) Conventional versus Foxp3(+) Regulatory T Cells}, series = {The journal of immunology}, volume = {197}, journal = {The journal of immunology}, publisher = {American Assoc. of Immunologists}, address = {Bethesda}, issn = {0022-1767}, doi = {10.4049/jimmunol.1600691}, pages = {3130 -- 3141}, year = {2016}, abstract = {CD4(+) Foxp3(+) regulatory T cells (Tregs) depend on CD28 signaling for their survival and function, a receptor that has been previously shown to activate the acid sphingomyelinase (Asm)/ceramide system. In this article, we show that the basal and CD28-induced Asm activity is higher in Tregs than in conventional CD4(+) T cells (Tconvs) of wild-type (wt) mice. In Asm-deficient (Smpd1(-/-); Asm(-/-)) mice, as compared with wt mice, the frequency of Tregs among CD4(+) T cells, turnover of the effector molecule CTLA-4, and their suppressive activity in vitro were increased. The biological significance of these findings was confirmed in our Treg-sensitive mouse model of measles virus (MV) CNS infection, in which we observed more infected neurons and less MV-specific CD8(+) T cells in brains of Asm(-/-) mice compared with wt mice. In addition to genetic deficiency, treatment of wt mice with the Asm inhibitor amitriptyline recapitulated the phenotype of Asm-deficient mice because it also increased the frequency of Tregs among CD4(+) T cells. Reduced absolute cell numbers of Tconvs after inhibitor treatment in vivo and extensive in vitro experiments revealed that Tregs are more resistant toward Asm inhibitor-induced cell death than Tconvs. Mechanistically, IL-2 was capable of providing crucial survival signals to the Tregs upon inhibitor treatment in vitro, shifting the Treg/Tconv ratio to the Treg side. Thus, our data indicate that Asm-inhibiting drugs should be further evaluated for the therapy of inflammatory and autoimmune disorders.}, language = {en} } @article{NojimaKonishiFreemanetal.2016, author = {Nojima, Hiroyuki and Konishi, Takanori and Freeman, Christopher M. and Schuster, Rebecca M. and Japtok, Lukasz and Kleuser, Burkhard and Edwards, Michael J. and Gulbins, Erich and Lentsch, Alex B.}, title = {Chemokine Receptors, CXCR1 and CXCR2, Differentially Regulate Exosome Release in Hepatocytes}, series = {PLoS one}, volume = {11}, journal = {PLoS one}, publisher = {PLoS}, address = {San Fransisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0161443}, pages = {6900 -- +}, year = {2016}, abstract = {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.}, language = {en} } @misc{HollmannReuterWerneretal.2016, author = {Hollmann, C. and Reuter, D. and Werner, S. and Avota, Elita and Mueller, N. and Japtok, Lukasz and Kleuser, Burkhard and Becker, Katrin Anne and Gulbins, Erich and Schneider-Schaulies, J{\"u}rgen and Beyersdorf, Niklas}, title = {Pharmacological inhibition of acid sphingomyelinase or genetic ablation enhances CD4(+) Foxp3(+) regulatory T cell activity}, series = {European journal of immunology}, volume = {46}, journal = {European journal of immunology}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0014-2980}, pages = {14 -- 14}, year = {2016}, language = {en} } @misc{NojimaKonishiJaptoketal.2016, author = {Nojima, Hiroyuki and Konishi, Takanori and Japtok, Lukasz and Kleuser, Burkhard and Edwards, Michael J. and Gulbins, Erich and Lentsch, Alex B.}, title = {Chemokine receptors, CXCR1 and CXCR2, differentially regulate exosome release in hepatocytes}, series = {Hepatology : official journal of the American Association for the Study of Liver Diseases}, volume = {64}, journal = {Hepatology : official journal of the American Association for the Study of Liver Diseases}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0270-9139}, pages = {165A -- 165A}, year = {2016}, language = {en} } @article{NojimaFreemanSchusteretal.2016, author = {Nojima, Hiroyuki and Freeman, Christopher M. and Schuster, Rebecca M. and Japtok, Lukasz and Kleuser, Burkhard and Edwards, Michael J. and Gulbins, Erich and Lentsch, Alex B.}, title = {Hepatocyte exosomes mediate liver repair and regeneration via sphingosine-1-phosphate}, series = {Journal of hepatology}, volume = {64}, journal = {Journal of hepatology}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0168-8278}, doi = {10.1016/j.jhep.2015.07.030}, pages = {60 -- 68}, year = {2016}, abstract = {Background \& Aims: Exosomes are small membrane vesicles involved in intercellular communication. Hepatocytes are known to release exosomes, but little is known about their biological function. We sought to determine if exosomes derived from hepatocytes contribute to liver repair and regeneration after injury. Methods: Exosomes derived from primary murine hepatocytes were isolated and characterized biochemically and biophysically. Using cultures of primary hepatocytes, we tested whether hepatocyte exosomes induced proliferation of hepatocytes in vitro. Using models of ischemia/reperfusion injury and partial hepatectomy, we evaluated whether hepatocyte exosomes promote hepatocyte proliferation and liver regeneration in vivo. Results: Hepatocyte exosomes, but not exosomes from other liver cell types, induce dose-dependent hepatocyte proliferation in vitro and in vivo. Mechanistically, hepatocyte exosomes directly fuse with target hepatocytes and transfer neutral ceramidase and sphingosine kinase 2 (SK2) causing increased synthesis of sphingosine-1-phosphate (S1P) within target hepatocytes. Ablation of exosomal SK prevents the proliferative effect of exosomes. After ischemia/reperfusion injury, the number of circulating exosomes with proliferative effects increases. Conclusions: Our data shows that hepatocyte-derived exosomes deliver the synthetic machinery to form S1P in target hepatocytes resulting in cell proliferation and liver regeneration after ischemia/reperfusion injury or partial hepatectomy. These findings represent a potentially novel new contributing mechanism of liver regeneration and have important implications for new therapeutic approaches to acute and chronic liver disease. (C) 2015 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.}, language = {en} }