@article{RamachandranSchirmerMuenstetal.2015, author = {Ramachandran, Sarada Devi and Schirmer, Katharina and M{\"u}nst, Bernhard and Heinz, Stefan and Ghafoory, Shahrouz and W{\"o}lfl, Stefan and Simon-Keller, Katja and Marx, Alexander and {\O}ie, Cristina Ionica and Ebert, Matthias P. and Walles, Heike and Braspenning, Joris and Breitkopf-Heinlein, Katja}, title = {In Vitro Generation of Functional Liver Organoid-Like Structures Using Adult Human Cells}, series = {PLoS One}, volume = {10}, journal = {PLoS One}, number = {10}, doi = {10.1371/journal.pone.0139345}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-139552}, pages = {e0139345}, year = {2015}, abstract = {In this study we used differentiated adult human upcyte (R) cells for the in vitro generation of liver organoids. Upcyte (R) cells are genetically engineered cell strains derived from primary human cells by lenti-viral transduction of genes or gene combinations inducing transient proliferation capacity (upcyte (R) process). Proliferating upcyte (R) cells undergo a finite number of cell divisions, i.e., 20 to 40 population doublings, but upon withdrawal of proliferation stimulating factors, they regain most of the cell specific characteristics of primary cells. When a defined mixture of differentiated human upcyte (R) cells (hepatocytes, liver sinusoidal endothelial cells (LSECs) and mesenchymal stem cells (MSCs)) was cultured in vitro on a thick layer of Matrigel\(^{TM}\), they self-organized to form liver organoid-like structures within 24 hours. When further cultured for 10 days in a bioreactor, these liver organoids show typical functional characteristics of liver parenchyma including activity of cytochromes P450, CYP3A4, CYP2B6 and CYP2C9 as well as mRNA expression of several marker genes and other enzymes. In summary, we hereby describe that 3D functional hepatic structures composed of primary human cell strains can be generated in vitro. They can be cultured for a prolonged period of time and are potentially useful ex vivo models to study liver functions.}, language = {en} } @article{ChengMacIntyreRamadanAbdelmohsenetal.2015, author = {Cheng, Cheng and MacIntyre, Lynsey and Ramadan Abdelmohsen, Usama and Horn, Hannes and Polymenakou, Paraskevi N. and Edrada-Ebel, RuAngelie and Hentschel, Ute}, title = {Biodiversity, Anti-Trypanosomal Activity Screening, and Metabolomic Profiling of Actinomycetes Isolated from Mediterranean Sponges}, series = {PLoS One}, volume = {10}, journal = {PLoS One}, number = {9}, doi = {10.1371/journal.pone.0138528}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-125138}, pages = {e0138528}, year = {2015}, abstract = {Marine sponge-associated actinomycetes are considered as promising sources for the discovery of novel biologically active compounds. In the present study, a total of 64 actinomycetes were isolated from 12 different marine sponge species that had been collected offshore the islands of Milos and Crete, Greece, eastern Mediterranean. The isolates were affiliated to 23 genera representing 8 different suborders based on nearly full length 16S rRNA gene sequencing. Four putatively novel species belonging to genera Geodermatophilus, Microlunatus, Rhodococcus and Actinomycetospora were identified based on a 16S rRNA gene sequence similarity of < 98.5\% to currently described strains. Eight actinomycete isolates showed bioactivities against Trypanosma brucei brucei TC221 with half maximal inhibitory concentration (IC50) values <20 μg/mL. Thirty four isolates from the Milos collection and 12 isolates from the Crete collection were subjected to metabolomic analysis using high resolution LC-MS and NMR for dereplication purposes. Two isolates belonging to the genera Streptomyces (SBT348) and Micromonospora (SBT687) were prioritized based on their distinct chemistry profiles as well as their anti-trypanosomal activities. These findings demonstrated the feasibility and efficacy of utilizing metabolomics tools to prioritize chemically unique strains from microorganism collections and further highlight sponges as rich source for novel and bioactive actinomycetes.}, language = {en} } @article{HoeggerKurlbaumMuelek2013, author = {H{\"o}gger, Petra and Kurlbaum, Max and M{\"u}lek, Melanie}, title = {Facilitated Uptake of a Bioactive Metabolite of Maritime Pine Bark Extract (Pycnogenol) into Human Erythrocytes}, series = {PLoS ONE}, journal = {PLoS ONE}, doi = {10.1371/journal.pone.0063197}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-96656}, year = {2013}, abstract = {Many plant secondary metabolites exhibit some degree of biological activity in humans. It is a common observation that individual plant-derived compounds in vivo are present in the nanomolar concentration range at which they usually fail to display measurable activity in vitro. While it is debatable that compounds detected in plasma are not the key effectors of bioactivity, an alternative hypothesis may take into consideration that measurable concentrations also reside in compartments other than plasma. We analysed the binding of constituents and the metabolite δ-(3,4-dihydroxy-phenyl)-γ-valerolactone (M1), that had been previously detected in plasma samples of human consumers of pine bark extract Pycnogenol, to human erythrocytes. We found that caffeic acid, taxifolin, and ferulic acid passively bind to red blood cells, but only the bioactive metabolite M1 revealed pronounced accumulation. The partitioning of M1 into erythrocytes was significantly diminished at higher concentrations of M1 and in the presence of glucose, suggesting a facilitated transport of M1 via GLUT-1 transporter. This concept was further supported by structural similarities between the natural substrate α-D-glucose and the S-isomer of M1. After cellular uptake, M1 underwent further metabolism by conjugation with glutathione. We present strong indication for a transporter-mediated accumulation of a flavonoid metabolite in human erythrocytes and subsequent formation of a novel glutathione adduct. The physiologic role of the adduct remains to be elucidated.}, language = {en} }