TY - GEN A1 - Kleuser, Burkhard T1 - The enigma of sphingolipids in health and disease T2 - International journal of molecular sciences Y1 - 2018 U6 - https://doi.org/10.3390/ijms19103126 SN - 1422-0067 VL - 19 IS - 10 PB - MDPI CY - Basel ER - TY - JOUR A1 - Kleuser, Burkhard T1 - Divergent role of sphingosine 1-phosphate in liver health and disease JF - International journal of molecular sciences N2 - Two decades ago, sphingosine 1-phosphate (S1P) was discovered as a novel bioactive molecule that regulates a variety of cellular functions. The plethora of S1P-mediated effects is due to the fact that the sphingolipid not only modulates intracellular functions but also acts as a ligand of G protein-coupled receptors after secretion into the extracellular environment. In the plasma, S1P is found in high concentrations, modulating immune cell trafficking and vascular endothelial integrity. The liver is engaged in modulating the plasma S1P content, as it produces apolipoprotein M, which is a chaperone for the S1P transport. Moreover, the liver plays a substantial role in glucose and lipid homeostasis. A dysfunction of glucose and lipid metabolism is connected with the development of liver diseases such as hepatic insulin resistance, non-alcoholic fatty liver disease, or liver fibrosis. Recent studies indicate that S1P is involved in liver pathophysiology and contributes to the development of liver diseases. In this review, the current state of knowledge about S1P and its signaling in the liver is summarized with a specific focus on the dysregulation of S1P signaling in obesity-mediated liver diseases. Thus, the modulation of S1P signaling can be considered as a potential therapeutic target for the treatment of hepatic diseases. KW - sphingolipids KW - sphingosine kinase KW - fibrosis KW - non-alcoholic fatty liver disease KW - insulin resistance KW - liver fibrosis Y1 - 2018 U6 - https://doi.org/10.3390/ijms19030722 SN - 1422-0067 VL - 19 IS - 3 PB - MDPI CY - Basel ER - TY - GEN A1 - Giulbudagian, Michael A1 - Yealland, Guy A1 - Hönzke, Stefan A1 - Edlich, Alexander A1 - Geisendörfer, Birte A1 - Kleuser, Burkhard A1 - Hedtrich, Sarah A1 - Calderón, Marcelo T1 - Breaking the barrier BT - potent anti-inflammatory activity following efficient topical delivery of etanercept using thermoresponsive nanogels T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Topical administration permits targeted, sustained delivery of therapeutics to human skin. Delivery to the skin, however, is typically limited to lipophilic molecules with molecular weight of < 500 Da, capable of crossing the stratum corneum. Nevertheless, there are indications protein delivery may be possible in barrier deficient skin, a condition found in several inflammatory skin diseases such as psoriasis, using novel nanocarrier systems. Methods: Water in water thermo-nanoprecipitation; dynamic light scattering; zeta potential measurement; nanoparticle tracking analysis; atomic force microscopy; cryogenic transmission electron microscopy; UV absorption; centrifugal separation membranes; bicinchoninic acid assay; circular dichroism; TNF alpha binding ELISA; inflammatory skin equivalent construction; human skin biopsies; immunohistochemistry; fluorescence microscopy; western blot; monocyte derived Langerhans cells; ELISA Results: Here, we report the novel synthesis of thermoresponsive nanogels (tNG) and the stable encapsulation of the anti-TNFa fusion protein etanercept (ETR) (similar to 150 kDa) without alteration to its structure, as well as temperature triggered release from the tNGs. Novel tNG synthesis without the use of organic solvents was conducted, permitting in situ encapsulation of protein during assembly, something that holds great promise for easy manufacture and storage. Topical application of ETR loaded tNGs to inflammatory skin equivalents or tape striped human skin resulted in efficient ETR delivery throughout the SC and into the viable epidermis that correlated with clear anti-inflammatory effects. Notably, effective ETR delivery depended on temperature triggered release following topical application. Conclusion: Together these results indicate tNGs hold promise as a biocompatible and easy to manufacture vehicle for stable protein encapsulation and topical delivery into barrier-deficient skin. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1030 KW - thermoresponsive-nanogel KW - topical KW - anti-inflammatory therapy KW - etanercept KW - skin equivalents Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-459301 SN - 1866-8372 IS - 1030 SP - 450 EP - 463 ER - TY - GEN A1 - Kleuser, Burkhard T1 - Divergent role of sphingosine 1-phosphate in liver health and disease T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Two decades ago, sphingosine 1-phosphate (S1P) was discovered as a novel bioactive molecule that regulates a variety of cellular functions. The plethora of S1P-mediated effects is due to the fact that the sphingolipid not only modulates intracellular functions but also acts as a ligand of G protein-coupled receptors after secretion into the extracellular environment. In the plasma, S1P is found in high concentrations, modulating immune cell trafficking and vascular endothelial integrity. The liver is engaged in modulating the plasma S1P content, as it produces apolipoprotein M, which is a chaperone for the S1P transport. Moreover, the liver plays a substantial role in glucose and lipid homeostasis. A dysfunction of glucose and lipid metabolism is connected with the development of liver diseases such as hepatic insulin resistance, non-alcoholic fatty liver disease, or liver fibrosis. Recent studies indicate that S1P is involved in liver pathophysiology and contributes to the development of liver diseases. In this review, the current state of knowledge about S1P and its signaling in the liver is summarized with a specific focus on the dysregulation of S1P signaling in obesity-mediated liver diseases. Thus, the modulation of S1P signaling can be considered as a potential therapeutic target for the treatment of hepatic diseases. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1051 KW - sphingolipids KW - sphingosine kinase KW - fibrosis KW - non-alcoholic fatty liver disease KW - insulinresistance KW - liver fibrosis Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-474398 SN - 1866-8372 IS - 1051 ER - TY - GEN A1 - Kleuser, Burkhard T1 - The enigma of sphingolipids in health and disease T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1040 KW - sphingosine-1-phosphate Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-472637 SN - 1866-8372 IS - 1040 ER - TY - JOUR A1 - Sahle, Fitsum Feleke A1 - Gerecke, Christian A1 - Kleuser, Burkhard A1 - Bodmeier, Roland T1 - Formulation and comparative in vitro evaluation of various dexamethasone-loaded pH-sensitive polymeric nanoparticles intended for dermal applications JF - International Journal of Pharmaceutics N2 - pH-sensitive nanoparticles have a great potential for dermal and transfollicular drug delivery. In this study, pH-sensitive, dexamethasone-loaded Eudragit (R) L 100, Eudragit (R) L 100-55, Eudragit (R) S 100, HPMCP-50, HPMCP-55 and cellulose acetate phthalate nanoparticles were prepared by nanoprecipitation and characterized. The pH-dependent swelling, erosion, dissolution and drug release kinetics were investigated in vitro using dynamic light scattering and Franz diffusion cells, respectively. Their toxicity potential was assessed by the ROS and MTT assays. 100-700 nm nanoparticles with high drug loading and entrapment efficiency were obtained. The nanoparticles bear no toxicity potential. Cellulose phthalates nanoparticles were more sensitive to pH than acrylates nanoparticles. They dissolved in 10 mM pH 7.5 buffer and released > 80% of the drug within 7 h. The acrylate nanoparticles dissolved in 40 mM pH 7.5 buffer and released 65-70% of the drug within 7 h. The nanoparticles remained intact in 10 and 40 mM pH 6.0 buffers (HPMCP nanoparticles dissolved in 40 mM pH 6.0 buffer) and released slowly. The nanoparticles properties could be modulated by blending the different polymers. In conclusion, various pH-sensitive nanoparticles that could release differently on the skin surface and dissolve and release in the hair follicles were obtained. KW - Cellulose acetate phthalate KW - Dexamethasone KW - Eudragit (R) KW - HPMCP KW - pH-sensitive nanoparticle KW - Skin nanocarrier Y1 - 2016 U6 - https://doi.org/10.1016/j.ijpharm.2016.11.029 SN - 0378-5173 SN - 1873-3476 VL - 516 IS - 1-2 SP - 21 EP - 31 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Edlich, Alexander A1 - Volz, Pierre A1 - Brodwolf, Robert A1 - Unbehauen, Michael A1 - Mundhenk, Lars A1 - Gruber, Achim D. A1 - Hedtrich, Sarah A1 - Haag, Rainer A1 - Alexiev, Ulrike A1 - Kleuser, Burkhard T1 - Crosstalk between core-multishell nanocarriers for cutaneous drug delivery and antigen-presenting cells of the skin JF - Biomaterials : biomaterials reviews online N2 - Owing their unique chemical and physical properties core-multishell (CMS) nanocarriers are thought to underlie their exploitable biomedical use for a topical treatment of skin diseases. This highlights the need to consider not only the efficacy of CMS nanocarriers but also the potentially unpredictable and adverse consequences of their exposure thereto. As CMS nanocarriers are able to penetrate into viable layers of normal and stripped human skin ex vivo as well as in in vitro skin disease models the understanding of nanoparticle crosstalk with components of the immune system requires thorough investigation. Our studies highlight the biocompatible properties of CMS nanocarriers on Langerhans cells of the skin as they did neither induce cytotoxicity and genotoxicity nor cause reactive oxygen species (ROS) or an immunological response. Nevertheless, CMS nanocarriers were efficiently taken up by Langerhans cells via divergent endocytic pathways. Bioimaging of CMS nanocarriers by fluorescence lifetime imaging microscopy (FLIM) and flow cytometry indicated not only a localization within the lysosomes but also an energy-dependent exocytosis of unmodified CMS nanocarriers into the extracellular environment. (C) 2018 Elsevier Ltd. All rights reserved. KW - Core-multishell nanocarriers KW - Fluorescence lifetime imaging microscopy KW - Langerhans cells KW - Nanoparticle uptake KW - Nanotoxicology Y1 - 2018 U6 - https://doi.org/10.1016/j.biomaterials.2018.01.058 SN - 0142-9612 SN - 1878-5905 VL - 162 SP - 60 EP - 70 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Hasan, Ahmed Abdallah Abdalrahman Mohamed A1 - von Websky, Karoline A1 - Reichetzeder, Christoph A1 - Tsuprykov, Oleg A1 - Gaballa, Mohamed Mahmoud Salem Ahmed A1 - Guo, Jingli A1 - Zeng, Shufei A1 - Delic, Denis A1 - Tammen, Harald A1 - Klein, Thomas A1 - Kleuser, Burkhard A1 - Hocher, Berthold T1 - Mechanisms of GLP-1 receptor-independent renoprotective effects of the dipeptidyl peptidase type 4 inhibitor linagliptin in GLP-1 receptor knockout mice with 5/6 nephrectomy JF - Kidney international : official journal of the International Society of Nephrology N2 - Dipeptidyl peptidase type 4 (DPP-4) inhibitors were reported to have beneficial effects in experimental models of chronic kidney disease. The underlying mechanisms are not completely understood. However, these effects could be mediated via the glucagon-like peptide-1 (GLP-1)/GLP-1 receptor (GLP1R) pathway. Here we investigated the renal effects of the DPP-4 inhibitor linagliptin in Glp1r-/- knock out and wild-type mice with 5/6 nephrectomy (5/6Nx). Mice were allocated to groups: sham + wild type + placebo; 5/6Nx+ wild type + placebo; 5/6Nx+ wild type + linagliptin; sham + knock out+ placebo; 5/6Nx + knock out+ placebo; 5/6Nx + knock out+ linagliptin. 5/6Nx caused the development of renal interstitial fibrosis, significantly increased plasma cystatin C and creatinine levels and suppressed renal gelatinase/collagenase, matrix metalloproteinase-1 and -13 activities; effects counteracted by linagliptin treatment in wildtype and Glp1r-/- mice. Two hundred ninety-eight proteomics signals were differentially regulated in kidneys among the groups, with 150 signals specific to linagliptin treatment as shown by mass spectrometry. Treatment significantly upregulated three peptides derived from collagen alpha-1(I), thymosin beta 4 and heterogeneous nuclear ribonucleoprotein Al (HNRNPA1) and significantly downregulated one peptide derived from Y box binding protein-1 (YB-1). The proteomics results were further confirmed using western blot and immunofluorescence microscopy. Also, 5/6Nx led to significant up-regulation of renal transforming growth factor-beta 1 and pSMAD3 expression in wild type mice and linagliptin significantly counteracted this up-regulation in wild type and GIplr-/- mice. Thus, the renoprotective effects of linagliptin cannot solely be attributed to the GLP-1/GLP1R pathway, highlighting the importance of other signaling pathways (collagen I homeostasis, HNRNPA1,YB-1,thymosin beta 4 and TGF-beta 1) influenced by DPP-4 inhibition. KW - chronic kidney disease KW - collagen I KW - fibrosis KW - Glp1r(-/-) mice KW - HNRNPA1 KW - linagliptin KW - proteomic analysis KW - TGF-beta 1 KW - thymosin beta 4 KW - YB-1 Y1 - 2019 U6 - https://doi.org/10.1016/j.kint.2019.01.010 SN - 0085-2538 SN - 1523-1755 VL - 95 IS - 6 SP - 1373 EP - 1388 PB - Elsevier CY - New York ER - TY - GEN A1 - Kleuser, Burkhard T1 - Medikamentennebenwirkungen auf Haut und Schleimhaut – allergische oder pharmakologisch erklärbare Reaktionen T2 - Allergologie T2 - Side Effects on Skin and Mucous Membrane - allergic or pharmacologically explainable Reactions Y1 - 2017 SN - 0344-5062 VL - 40 IS - 10 SP - 420 EP - 421 PB - Dustri-Verlag CY - Deisenhofen-München ER - TY - JOUR A1 - Nitezki, Tina A1 - Kleuser, Burkhard A1 - Krämer, Stephanie T1 - Fatal gastric distension in a gold thioglucose mouse model of obesity JF - Laboratory Animals N2 - This case report addresses the problem of underreporting negative results and adverse side effects in animal testing. We present our findings regarding a hyperphagic mouse model associated with unforeseen high mortality. The results outline the necessity of reporting detailed information in the literature to avoid duplication. Obese mouse models are essential in the study of obesity, metabolic syndrome and diabetes mellitus. An experimental model of obesity can be induced by the administration of gold thioglucose (GTG). After transcending the blood-brain barrier, the GTG molecule interacts with regions of the ventromedial hypothalamus, thereby primarily targeting glucose-sensitive neurons. When these neurons are impaired, mice become insensitive to the satiety effects of glucose and develop hyperphagia. In a pilot study for optimising dosage and body weight development, C57BL/6 mice were treated with GTG (0.5 mg/g body weight) or saline, respectively. Animals were provided a physiological amount of standard diet (5 g per animal) for the first 24 hours after treatment to prevent gastric dilatation. Within 24 hours after GTG injection, all GTG-treated animals died of gastric overload and subsequent circulatory shock. Animals developed severe attacks of hyperphagia, and as the amount of provided chow was restricted, mice exhibited unforeseen pica and ingested bedding material. These observations strongly suggest that restricted feeding is contraindicated concerning GTG application. Presumably, the impulse of excessive food intake was a strong driving force. Therefore, the actual degree of suffering in the GTG-induced model of hyperphagia should be revised from moderate to severe. KW - appetite KW - distress KW - refinement KW - mortality Y1 - 2018 U6 - https://doi.org/10.1177/0023677218803384 SN - 0023-6772 SN - 1758-1117 VL - 53 IS - 1 SP - 89 EP - 94 PB - Sage Publ. CY - Thousand Oaks ER -