@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} } @misc{WalterCollenburgJaptoketal.2016, author = {Walter, Tim and Collenburg, Lena and Japtok, Lukasz and Kleuser, Burkhard and Schneider-Schaulies, Sibylle and M{\"u}ller, Nora and Becam, Jerome and Schubert-Unkmeir, Alexandra and Kong, Ji Na and Bieberich, Erhard and Seibel, J{\"u}rgen}, title = {Incorporation and visualization of azido-functionalized N-oleoyl serinol in Jurkat cells, mouse brain astrocytes, 3T3 fibroblasts and human brain microvascular endothelial cells}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-394960}, pages = {3}, year = {2016}, abstract = {The synthesis and biological evaluation of azido-N-oleoyl serinol is reported. It mimicks biofunctional lipid ceramides and has shown to be capable of click reactions for cell membrane imaging in Jurkat and human brain microvascular endothelial cells.}, language = {en} } @article{CollenburgWalterBurgertetal.2016, author = {Collenburg, Lena and Walter, Tim and Burgert, Anne and Mueller, Nora and Seibel, Juergen and Japtok, Lukasz and Kleuser, Burkhard and Sauer, Markus and Schneider-Schaulies, Sibylle}, title = {A Functionalized Sphingolipid Analogue for Studying Redistribution during Activation in Living T Cells}, series = {The journal of immunology}, volume = {196}, journal = {The journal of immunology}, publisher = {American Assoc. of Immunologists}, address = {Bethesda}, issn = {0022-1767}, doi = {10.4049/jimmunol.1502447}, pages = {3951 -- 3962}, year = {2016}, abstract = {Sphingolipids are major components of the plasma membrane. In particular, ceramide serves as an essential building hub for complex sphingolipids, but also as an organizer of membrane domains segregating receptors and signalosomes. Sphingomyelin breakdown as a result of sphingomyelinase activation after ligation of a variety of receptors is the predominant source of ceramides released at the plasma membrane. This especially applies to T lymphocytes where formation of ceramide-enriched membrane microdomains modulates TCR signaling. Because ceramide release and redistribution occur very rapidly in response to receptor ligation, novel tools to further study these processes in living T cells are urgently needed. To meet this demand, we synthesized nontoxic, azido-functionalized ceramides allowing for bio-orthogonal click-reactions to fluorescently label incorporated ceramides, and thus investigate formation of ceramide-enriched domains. Azido-functionalized C-6-ceramides were incorporated into and localized within plasma membrane microdomains and proximal vesicles in T cells. They segregated into clusters after TCR, and especially CD28 ligation, indicating efficient sorting into plasma membrane domains associated with T cell activation; this was abolished upon sphingomyelinase inhibition. Importantly, T cell activation was not abrogated upon incorporation of the compound, which was efficiently excluded from the immune synapse center as has previously been seen in Ab-based studies using fixed cells. Therefore, the functionalized ceramides are novel, highly potent tools to study the subcellular redistribution of ceramides in the course of T cell activation. Moreover, they will certainly also be generally applicable to studies addressing rapid stimulation-mediated ceramide release in living cells.}, language = {en} } @article{WalterCollenburgJaptoketal.2016, author = {Walter, T. and Collenburg, Lena and Japtok, Lukasz and Kleuser, Burkhard and Schneider-Schaulies, Sibylle and Mueller, N. and Becam, Jerome and Schubert-Unkmeir, A. and Kong, J. N. and Bieberich, Erhard and Seibel, J.}, title = {Incorporation and visualization of azido-functionalized N-oleoyl serinol in Jurkat cells, mouse brain astrocytes, 3T3 fibroblasts and human brain microvascular endothelial cells}, series = {Chemical communications}, volume = {52}, journal = {Chemical communications}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1359-7345}, doi = {10.1039/c6cc02879a}, pages = {8612 -- 8614}, year = {2016}, abstract = {The synthesis and biological evaluation of azido-N-oleoyl serinol is reported. It mimicks biofunctional lipid ceramides and has shown to be capable of click reactions for cell membrane imaging in Jurkat and human brain microvascular endothelial cells.}, language = {en} } @article{RakersSchumacherMeinletal.2016, author = {Rakers, Christin and Schumacher, Fabian and Meinl, Walter and Glatt, Hansruedi and Kleuser, Burkhard and Wolber, Gerhard}, title = {In Silico Prediction of Human Sulfotransferase 1E1 Activity Guided by Pharmacophores from Molecular Dynamics Simulations}, series = {The journal of biological chemistry}, volume = {291}, journal = {The journal of biological chemistry}, publisher = {American Society for Biochemistry and Molecular Biology}, address = {Bethesda}, issn = {0021-9258}, doi = {10.1074/jbc.M115.685610}, pages = {58 -- 71}, year = {2016}, abstract = {Acting during phase II metabolism, sulfotransferases (SULTs) serve detoxification by transforming a broad spectrum of compounds from pharmaceutical, nutritional, or environmental sources into more easily excretable metabolites. However, SULT activity has also been shown to promote formation of reactive metabolites that may have genotoxic effects. SULT subtype 1E1 (SULT1E1) was identified as a key player in estrogen homeostasis, which is involved in many physiological processes and the pathogenesis of breast and endometrial cancer. The development of an in silico prediction model for SULT1E1 ligands would therefore support the development of metabolically inert drugs and help to assess health risks related to hormonal imbalances. Here, we report on a novel approach to develop a model that enables prediction of substrates and inhibitors of SULT1E1. Molecular dynamics simulations were performed to investigate enzyme flexibility and sample protein conformations. Pharmacophores were developed that served as a cornerstone of the model, and machine learning techniques were applied for prediction refinement. The prediction model was used to screen the DrugBank (a database of experimental and approved drugs): 28\% of the predicted hits were reported in literature as ligands of SULT1E1. From the remaining hits, a selection of nine molecules was subjected to biochemical assay validation and experimental results were in accordance with the in silico prediction of SULT1E1 inhibitors and substrates, thus affirming our prediction hypotheses.}, language = {en} }