@article{MuenstThierWinnemoelleretal.2016,
  author    = {M{\"u}nst, Bernhard and Thier, Marc Christian and Winnem{\"o}ller, Dirk and Helfen, Martina and Thummer, Rajkumar P. and Edenhofer, Frank},
  title     = {Nanog induces suppression of senescence through downregulation of p27\(^{KIP1}\) expression},
  series = {Journal of Cell Science},
  volume    = {129},
  journal   = {Journal of Cell Science},
  number    = {5},
  doi       = {10.1242/jcs.167932},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-190761},
  pages     = {912-920},
  year      = {2016},
  abstract  = {A comprehensive analysis of the molecular network of cellular factors establishing and maintaining pluripotency as well as self renewal of pluripotent stem cells is key for further progress in understanding basic stem cell biology. Nanog is necessary for the natural induction of pluripotency in early mammalian development but dispensable for both its maintenance and its artificial induction. To gain further insight into the molecular activity of Nanog, we analyzed the outcomes of Nanog gain-of-function in various cell models employing a recently developed biologically active recombinant cell-permeant protein, Nanog-TAT. We found that Nanog enhances the proliferation of both NIH 3T3 and primary fibroblast cells. Nanog transduction into primary fibroblasts results in suppression of senescence-associated beta-galactosidase activity. Investigation of cell cycle factors revealed that transient activation of Nanog correlates with consistent downregulation of the cell cycle inhibitor p27\(^{KIP1}\) (also known as CDKN1B). By performing chromatin immunoprecipitation analysis, we confirmed bona fide Nanog-binding sites upstream of the p27\(^{KIP1}\) gene, establishing a direct link between physical occupancy and functional regulation. Our data demonstrates that Nanog enhances proliferation of fibroblasts through transcriptional regulation of cell cycle inhibitor p27 gene.},
  language  = {en}
}
@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{PeitzMuenstThummeretal.2014,
  author    = {Peitz, Michael and M{\"u}nst, Bernhard and Thummer, Rajkumar P. and Helfen, Martina and Edenhofer, Frank},
  title     = {Cell-permeant recombinant Nanog protein promotes pluripotency by inhibiting endodermal specification},
  series = {Stem Cell Research},
  volume    = {12},
  journal   = {Stem Cell Research},
  number    = {3},
  issn      = {1876-7753},
  doi       = {10.1016/j.scr.2014.02.006},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-119740},
  pages     = {680-689},
  year      = {2014},
  abstract  = {A comprehensive understanding of the functional network of transcription factors establishing and maintaining pluripotency is key for the development of biomedical applications of stem cells. Nanog plays an important role in early development and is essential to induce natural pluripotency in embryonic stem cells (ESCs). Inducible gain-of-function systems allowing a precise control over time and dosage of Nanog activity would be highly desirable to study its vital role in the establishment and maintenance of pluripotency at molecular level. Here we engineered a recombinant cell permeable version of Nanog by fusing it with the cell penetrating peptide TAT. Nanog-TAT can be readily expressed in and purified from E. coli and binds to a consensus Nanog DNA sequence. At cellular level it enhances proliferation and self-renewal of ESCs in the absence of leukemia inhibitory factor (LIF). Nanog-TAT together with LIF acts synergistically as judged by enhanced clonogenicity and activation of an Oct4-promoter-driven GFP reporter gene. Furthermore Nanog-TAT, in the absence of LIF, promotes pluripotency by inhibiting endodermal specification in a Stat3-independent manner. Our results demonstrate that Nanog protein transduction is an attractive tool allowing control over dose and time of addition to the cells for studying the molecular control of pluripotency without genetic manipulation.},
  language  = {en}
}