TY - JOUR A1 - Gerecke, Christian A1 - Edlich, Alexander A1 - Giulbudagian, Michael A1 - Schumacher, Fabian A1 - Zhang, Nan A1 - Said, Andre A1 - Yealland, Guy A1 - Lohan, Silke B. A1 - Neumann, Falko A1 - Meinke, Martina C. A1 - Ma, Nan A1 - Calderon, Marcelo A1 - Hedtrich, Sarah A1 - Schaefer-Korting, Monika A1 - Kleuser, Burkhard T1 - Biocompatibility and characterization of polyglycerol-based thermoresponsive nanogels designed as novel drug-delivery systems and their intracellular localization in keratinocytes JF - Nanotoxicology N2 - Novel nanogels that possess the capacity to change their physico-chemical properties in response to external stimuli are promising drug-delivery candidates for the treatment of severe skin diseases. As thermoresponsive nanogels (tNGs) are capable of enhancing penetration through biological barriers such as the stratum corneum and are taken up by keratinocytes of human skin, potential adverse consequences of their exposure must be elucidated. In this study, tNGs were synthesized from dendritic polyglycerol (dPG) and two thermoresponsive polymers. tNG_dPG_tPG are the combination of dPG with poly(glycidyl methyl ether-co-ethyl glycidyl ether) (p(GME-co-EGE)) and tNG_dPG_pNIPAM the one with poly(N-isopropylacrylamide) (pNIPAM). Both thermoresponsive nanogels are able to incorporate high amounts of dexamethasone and tacrolimus, drugs used in the treatment of severe skin diseases. Cellular uptake, intracellular localization and the toxicological properties of the tNGs were comprehensively characterized in primary normal human keratinocytes (NHK) and in spontaneously transformed aneuploid immortal keratinocyte cell line from adult human skin (HaCaT). Laser scanning confocal microscopy revealed fluorescently labeled tNGs entered into the cells and localized predominantly within lysosomal compartments. MTT assay, comet assay and carboxy-H2DCFDA assay, demonstrated neither cytotoxic or genotoxic effects, nor any induction of reactive oxygen species of the tNGs in keratinocytes. In addition, both tNGs were devoid of eye irritation potential as shown by bovine corneal opacity and permeability (BCOP) test and red blood cell (RBC) hemolysis assay. Therefore, our study provides evidence that tNGs are locally well tolerated and underlines their potential for cutaneous drug delivery. KW - Drug delivery KW - nanoparticles KW - particle characterization KW - keratinocytes KW - nanotoxicology Y1 - 2017 U6 - https://doi.org/10.1080/17435390.2017.1292371 SN - 1743-5390 SN - 1743-5404 VL - 11 SP - 267 EP - 277 PB - Routledge, Taylor & Francis Group CY - Abingdon ER - TY - GEN A1 - Gerecke, Christian A1 - Edlich, Alexander A1 - Giulbudagian, Michael A1 - Schumacher, Fabian A1 - Zhang, Nan A1 - Said, Andre A1 - Yealland, Guy A1 - Lohan, Silke B. A1 - Neumann, Falko A1 - Meinke, Martina C. A1 - Ma, Nan A1 - Calderón, Marcelo A1 - Hedtrich, Sarah A1 - Schäfer-Korting, Monika A1 - Kleuser, Burkhard T1 - Biocompatibility and characterization of polyglycerol-based thermoresponsive nanogels designed as novel drug-delivery systems and their intracellular localization in keratinocytes N2 - Novel nanogels that possess the capacity to change their physico-chemical properties in response to external stimuli are promising drug-delivery candidates for the treatment of severe skin diseases. As thermoresponsive nanogels (tNGs) are capable of enhancing penetration through biological barriers such as the stratum corneum and are taken up by keratinocytes of human skin, potential adverse consequences of their exposure must be elucidated. In this study, tNGs were synthesized from dendritic polyglycerol (dPG) and two thermoresponsive polymers. tNG_dPG_tPG are the combination of dPG with poly(glycidyl methyl ether-co-ethyl glycidyl ether) (p(GME-co-EGE)) and tNG_dPG_pNIPAM the one with poly(N-isopropylacrylamide) (pNIPAM). Both thermoresponsive nanogels are able to incorporate high amounts of dexamethasone and tacrolimus, drugs used in the treatment of severe skin diseases. Cellular uptake, intracellular localization and the toxicological properties of the tNGs were comprehensively characterized in primary normal human keratinocytes (NHK) and in spontaneously transformed aneuploid immortal keratinocyte cell line from adult human skin (HaCaT). Laser scanning confocal microscopy revealed fluorescently labeled tNGs entered into the cells and localized predominantly within lysosomal compartments. MTT assay, comet assay and carboxy-H2DCFDA assay, demonstrated neither cytotoxic or genotoxic effects, nor any induction of reactive oxygen species of the tNGs in keratinocytes. In addition, both tNGs were devoid of eye irritation potential as shown by bovine corneal opacity and permeability (BCOP) test and red blood cell (RBC) hemolysis assay. Therefore, our study provides evidence that tNGs are locally well tolerated and underlines their potential for cutaneous drug delivery. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 335 KW - Drug delivery KW - nanoparticles KW - particle characterization KW - keratinocytes KW - nanotoxicology Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-395325 ER - TY - JOUR A1 - Ahlberg, Sebastian A1 - Rancan, Fiorenza A1 - Epple, Matthias A1 - Loza, Kateryna A1 - Höppe, David A1 - Lademann, Jürgen A1 - Vogt, Annika A1 - Kleuser, Burkhard A1 - Gerecke, Christian A1 - Meinke, Martina C. T1 - Comparison of different methods to study effects of silver nanoparticles on the pro- and antioxidant status of human keratinocytes and fibroblasts JF - Methods : focusing on rapidly developing techniques KW - Oxidative stress KW - Dichlorofluorescein assay KW - Electron paramagnetic resonance spectroscopy KW - HaCaT cells KW - Glutathione KW - Free radicals Y1 - 2016 U6 - https://doi.org/10.1016/j.ymeth.2016.05.015 SN - 1046-2023 SN - 1095-9130 VL - 109 SP - 55 EP - 63 PB - Elsevier CY - San Diego ER - TY - CHAP A1 - Gerecke, Christian A1 - Scholtka, Bettina T1 - Detection of low level adenomatous polyposis coli(APC) gene mutatons by wild-type blocking-pcr and high resolution melting analysis T2 - Clinical chemistry and laboratory medicine : journal of the Forum of the European Societies of Clinical Chemistry - the European Branch of the International Federation of Clinical Chemistry and Laboratory Medicine Y1 - 2011 SN - 1434-6621 VL - 49 IS - 1 SP - S603 EP - S603 PB - De Gruyter CY - Berlin ER - TY - THES A1 - Gerecke, Christian T1 - Entwicklung eines hochsensitiven Verfahrens zur Detektion von Mutationen im Tumorsuppressor APC und Analyse des Methylierungsstatus der Genpromotoren von ITGA4, TFPI2 und Vimentin in humanen Kolongeweben und Fäzes Y1 - 2013 CY - Potsdam ER - TY - JOUR A1 - Wetzel, Alexandra Nicole A1 - Scholtka, Bettina A1 - Gerecke, Christian A1 - Kleuser, Burkhard T1 - Epigenetic histone modulation contributes to improvements in inflammatory bowel disease via EBI3 JF - Cellular and molecular life sciences N2 - Ulcerative colitis (UC) is characterized by relapsing-remitting inflammatory episodes paralleled by varying cytokine levels, suggesting that switching epigenetic processes might be involved. However, the epigenetic impact on cytokine levels in colitis is mostly unexplored. The heterodimeric interleukin (IL)-12 cytokine family have various functions in both pro- and anti-inflammatory processes. The family member IL-35 (EBI3/IL-12p35) was recently reported to play an anti-inflammatory role in UC. Therefore, we aimed to investigate a possible epigenetic regulation of the IL-35 subunits in vitro and in vivo, and to examine the epigenetic targeting of EBI3 expression as a therapeutic option for UC. Exposure to either the pro-inflammatory TNF alpha or to histone deacetylase inhibitors (HDACi) significantly increased EBI3 expression in Human Colon Epithelial Cells (HCEC) generated from healthy tissue. When applied in combination, a drastic upregulation of EBI3 expression occurred, suggesting a synergistic mechanism. Consequently, IL-35 was increased as well. In vivo, the intestines of HDACi-treated wild-type mice exhibited reduced pathological signs of colitis compared to non-treated colitic mice. However, the improvement by HDACi treatment was completely lost in Ebi3-deficient mice (Ebi3(-/-)). In fact, HDACi appeared to exacerbate the disease phenotype in Ebi3(-/-). In conclusion, our results reveal that under inflammatory conditions, EBI3 is upregulated by the epigenetic mechanism of histone acetylation. The in vivo data show that the deficiency of EBI3 plays a key role in colitis manifestation. Concordantly, our data suggest that conditions promoting histone acetylation, such as upon HDACi application, improve colitis by a mechanism involving the local formation of the anti-inflammatory cytokine IL-35. KW - Histone deacetylase inhibitor KW - Inhibitory cytokines KW - Interleukin-35 KW - SAHA KW - Ulcerative colitis Y1 - 2020 U6 - https://doi.org/10.1007/s00018-020-03451-9 SN - 1420-682X SN - 1420-9071 VL - 77 IS - 23 SP - 5017 EP - 5030 PB - Springer International Publishing AG CY - Cham (ZG) 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 - Balzus, Benjamin A1 - Sahle, Fitsum Feleke A1 - Hönzke, Stefan A1 - Gerecke, Christian A1 - Schumacher, Fabian A1 - Hedtrich, Sarah A1 - Kleuser, Burkhard A1 - Bodmeier, Roland T1 - Formulation and ex vivo evaluation of polymeric nanoparticles for controlled delivery of corticosteroids to the skin and the corneal epithelium JF - European journal of pharmaceutics and biopharmaceutics : EJPB ; official journal of the International Association for Pharmaceutical Technology N2 - Controlled delivery of corticosteroids using nanoparticles to the skin and corneal epithelium may reduce their side effects and maximize treatment effectiveness. Dexamethasone-loaded ethyl cellulose, Eudragit® RS and ethyl cellulose/Eudragit® RS nanoparticles were prepared by the solvent evaporation method. Dexamethasone release from the polymeric nanoparticles was investigated in vitro using Franz diffusion cells. Drug penetration was also assessed ex vivo using excised human skin. Nanoparticle toxicity was determined by MTT and H2DCFDA assays. Eudragit® RS nanoparticles were smaller and positively charged but had a lower dexamethasone loading capacity (0.3–0.7%) than ethyl cellulose nanoparticles (1.4–2.2%). By blending the two polymers (1:1), small (105 nm), positively charged (+37 mV) nanoparticles with sufficient dexamethasone loading (1.3%) were obtained. Dexamethasone release and penetration significantly decreased with decreasing drug to polymer ratio and increased when Eudragit® RS was blended with ethyl cellulose. Ex vivo, drug release and penetration from the nanoparticles was slower than a conventional cream. The nanoparticles bear no toxicity potentials except ethyl cellulose nanoparticles had ROS generation potential at high concentration. In conclusion, the nanoparticles showed great potential to control the release and penetration of corticosteroids on the skin and mucus membrane and maximize treatment effectiveness. KW - Dermal delivery KW - Dexamethasone KW - Ethyl cellulose KW - Eudragit (R) RS KW - Ocular delivery KW - Polymeric nanoparticle Y1 - 2017 U6 - https://doi.org/10.1016/j.ejpb.2017.02.001 SN - 0939-6411 SN - 1873-3441 VL - 115 SP - 122 EP - 130 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Sahle, Fitsum Feleke A1 - Balzus, Benjamin A1 - Gerecke, Christian A1 - Kleuser, Burkhard A1 - Bodmeier, Roland T1 - Formulation and in vitro evaluation of polymeric enteric nanoparticles as dermal carriers with pH-dependent targeting potential JF - European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences, EUFEPS N2 - 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. KW - Dexamethasone KW - Enteric polymer KW - Eudragit L 100 KW - pH-sensitive nanoparticles KW - Skin nanocarrier KW - Erosion kinetics Y1 - 2016 U6 - https://doi.org/10.1016/j.ejps.2016.07.004 SN - 0928-0987 SN - 1879-0720 VL - 92 SP - 98 EP - 109 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Gerecke, Christian A1 - Scholtka, Bettina A1 - Loewenstein, Yvonne A1 - Fait, Isabel A1 - Gottschalk, Uwe A1 - Rogoll, Dorothee A1 - Melcher, Ralph A1 - Kleuser, Burkhard T1 - Hypermethylation of ITGA4, TFPI2 and VIMENTIN promoters is increased in inflamed colon tissue: putative risk markers for colitis-associated cancer JF - Journal of cancer research and clinical oncology : official organ of the Deutsche Krebsgesellschaft N2 - 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. KW - Epigenetic KW - DNA methylation KW - Colon cancer KW - Colitis KW - Gastrointestinal tract KW - Biomarker Y1 - 2015 U6 - https://doi.org/10.1007/s00432-015-1972-8 SN - 0171-5216 SN - 1432-1335 VL - 141 IS - 12 SP - 2097 EP - 2107 PB - Springer CY - New York ER -