@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} } @misc{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}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-99508}, pages = {10}, year = {2015}, abstract = {Overexposure to the essential metal manganese (Mn) can result in an irreversible condition known as manganism that shares similar pathophysiology with Parkinson's disease (PD), including dopaminergic (DAergic) cell loss that leads to motor and cognitive impairments. However, the mechanisms behind this neurotoxicity and its relationship with PD remain unclear. Many genes confer risk for autosomal recessive, early-onset PD, including the parkin/PARK2 gene that encodes for the E3 ubiquitin ligase Parkin. Using Caenorhabditis elegans (C. elegans) as an invertebrate model that conserves the DAergic system, we previously reported significantly increased Mn accumulation in pdr-1/parkin mutants compared to wildtype (WT) animals. For the current study, we hypothesize that this enhanced accumulation is due to alterations in Mn transport in the pdr-1 mutants. While no change in mRNA expression of the major Mn importer proteins (smf-1-3) was found in pdr-1 mutants, significant downregulation in mRNA levels of the putative Mn exporter ferroportin (fpn-1.1) was observed. Using a strain overexpressing fpn-1.1 in worms lacking pdr-1, we show evidence for attenuation of several endpoints of Mn-induced toxicity, including survival, metal accumulation, mitochondrial copy number and DAergic integrity, compared to pdr-1 mutants alone. These changes suggest a novel role of pdr-1 in modulating Mn export through altered transporter expression, and provides further support of metal dyshomeostasis as a component of Parkinsonism pathophysiology.}, language = {en} }