@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{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{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}
}