@article{YanHongChenetal.2013,
author = {Yan, Yan and Hong, Ni and Chen, Tiansheng and Li, Mingyou and Wang, Tiansu and Guan, Guijun and Qiao, Yongkang and Chen, Songlin and Schartl, Manfred and Li, Chang-Ming and Hong, Yunhan},
title = {p53 Gene Targeting by Homologous Recombination in Fish ES Cells},
series = {PLoS One},
volume = {8},
journal = {PLoS One},
number = {3},
doi = {10.1371/journal.pone.0059400},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133416},
pages = {e59400},
year = {2013},
abstract = {Background: Gene targeting (GT) provides a powerful tool for the generation of precise genetic alterations in embryonic stem (ES) cells to elucidate gene function and create animal models for human diseases. This technology has, however, been limited to mouse and rat. We have previously established ES cell lines and procedures for gene transfer and selection for homologous recombination (HR) events in the fish medaka (Oryzias latipes). Methodology and Principal Findings: Here we report HR-mediated GT in this organism. We designed a GT vector to disrupt the tumor suppressor gene p53 (also known as tp53). We show that all the three medaka ES cell lines, MES1 similar to MES3, are highly proficient for HR, as they produced detectable HR without drug selection. Furthermore, the positive-negative selection (PNS) procedure enhanced HR by similar to 12 folds. Out of 39 PNS-resistant colonies analyzed, 19 (48.7\%) were positive for GT by PCR genotyping. When 11 of the PCR-positive colonies were further analyzed, 6 (54.5\%) were found to be bona fide homologous recombinants by Southern blot analysis, sequencing and fluorescent in situ hybridization. This produces a high efficiency of up to 26.6\% for p53 GT under PNS conditions. We show that p53 disruption and long-term propagation under drug selection conditions do not compromise the pluripotency, as p53-targeted ES cells retained stable growth, undifferentiated phenotype, pluripotency gene expression profile and differentiation potential in vitro and in vivo. Conclusions: Our results demonstrate that medaka ES cells are proficient for HR-mediated GT, offering a first model organism of lower vertebrates towards the development of full ES cell-based GT technology.},
language = {en}
}
@article{WeiderWegenerSchmittetal.2015,
author = {Weider, Matthias and Wegener, Am{\´e}lie and Schmitt, Christian and K{\"u}spert, Melanie and Hillg{\"a}rtner, Simone and B{\"o}sl, Michael R. and Hermans-Borgmeyer, Irm and Nait-Oumesmar, Brahim and Wegner, Michael},
title = {Elevated in vivo levels of a single transcription factor directly convert satellite glia into oligodendrocyte-like cells},
series = {PLoS Genetics},
volume = {11},
journal = {PLoS Genetics},
number = {2},
doi = {10.1371/journal.pgen.1005008},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-144123},
pages = {e1005008},
year = {2015},
abstract = {Oligodendrocytes are the myelinating glia of the central nervous system and ensure rapid saltatory conduction. Shortage or loss of these cells leads to severe malfunctions as observed in human leukodystrophies and multiple sclerosis, and their replenishment by reprogramming or cell conversion strategies is an important research aim. Using a transgenic approach we increased levels of the transcription factor Sox10 throughout the mouse embryo and thereby prompted Fabp7-positive glial cells in dorsal root ganglia of the peripheral nervous system to convert into cells with oligodendrocyte characteristics including myelin gene expression. These rarely studied and poorly characterized satellite glia did not go through a classic oligodendrocyte precursor cell stage. Instead, Sox10 directly induced key elements of the regulatory network of differentiating oligodendrocytes, including Olig2, Olig1, Nkx2.2 and Myrf. An upstream enhancer mediated the direct induction of the Olig2 gene. Unlike Sox10, Olig2 was not capable of generating oligodendrocyte-like cells in dorsal root ganglia. Our findings provide proof-of-concept that Sox10 can convert conducive cells into oligodendrocyte-like cells in vivo and delineates options for future therapeutic strategies.},
language = {en}
}
@article{SunOrtegaTanetal.2018,
author = {Sun, Ping and Ortega, Gabriela and Tan, Yan and Hua, Qian and Riederer, Peter F. and Deckert, J{\"u}rgen and Schmitt-B{\"o}hrer, Angelika G.},
title = {Streptozotocin impairs proliferation and differentiation of adult hippocampal neural stem cells in vitro-correlation with alterations in the expression of proteins associated with the insulin system},
series = {Frontiers in Aging Neuroscience},
volume = {10},
journal = {Frontiers in Aging Neuroscience},
number = {145},
doi = {10.3389/fnagi.2018.00145},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-176741},
year = {2018},
abstract = {Rats intracerebroventricularily (icv) treated with streptozotocin (STZ), shown to generate an insulin resistant brain state, were used as an animal model for the sporadic form of Alzheimer's disease (sAD). Previously, we showed in an in vivo study that 3 months after STZ icv treatment hippocampal adult neurogenesis (AN) is impaired. In the present study, we examined the effects of STZ on isolated adult hippocampal neural stem cells (NSCs) using an in vitro approach. We revealed that 2.5 mM STZ inhibits the proliferation of NSCs as indicated by reduced number and size of neurospheres as well as by less BrdU-immunoreactive NSCs. Double immunofluorescence stainings of NSCs already being triggered to start with their differentiation showed that STZ primarily impairs the generation of new neurons, but not of astrocytes. For revealing mechanisms possibly involved in mediating STZ effects we analyzed expression levels of insulin/glucose system-related molecules such as the glucose transporter (GLUT) 1 and 3, the insulin receptor (IR) and the insulin-like growth factor (IGF) 1 receptor. Applying quantitative Real time-PCR (qRT-PCR) and immunofluorescence stainings we showed that STZ exerts its strongest effects on GLUT3 expression, as GLUT3 mRNA levels were found to be reduced in NSCs, and less GLUT3-immunoreactive NSCs as well as differentiating cells were detected after STZ treatment. These findings suggest that cultured NSCs are a good model for developing new strategies to treat nerve cell loss in AD and other degenerative disorders.},
language = {en}
}
@article{SchilbachAlkhaledWelkeretal.2015,
author = {Schilbach, Karin and Alkhaled, Mohammed and Welker, Christian and Eckert, Franziska and Blank, Gregor and Ziegler, Hendrik and Sterk, Marco and M{\"u}ller, Friederike and Sonntag, Katja and Wieder, Thomas and Braum{\"u}ller, Heidi and Schmitt, Julia and Eyrich, Matthias and Schleicher, Sabine and Seitz, Christian and Erbacher, Annika and Pichler, Bernd J. and M{\"u}ller, Hartmut and Tighe, Robert and Lim, Annick and Gillies, Stephen D. and Strittmatter, Wolfgang and R{\"o}cken, Martin and Handgretinger, Rupert},
title = {Cancer-targeted IL-12 controls human rhabdomyosarcoma by senescence induction and myogenic differentiation},
series = {OncoImmunology},
volume = {4},
journal = {OncoImmunology},
number = {7},
doi = {10.1080/2162402X.2015.1014760},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-154579},
pages = {e1014760},
year = {2015},
abstract = {Stimulating the immune system to attack cancer is a promising approach, even for the control of advanced cancers. Several cytokines that promote interferon-γ-dominated immune responses show antitumor activity, with interleukin 12 (IL-12) being of major importance. Here, we used an antibody-IL-12 fusion protein (NHS-IL12) that binds histones of necrotic cells to treat human sarcoma in humanized mice. Following sarcoma engraftment, NHS-IL12 therapy was combined with either engineered IL-7 (FcIL-7) or IL-2 (IL-2MAB602) for continuous cytokine bioavailability. NHS-IL12 strongly induced innate and adaptive antitumor immunity when combined with IL-7 or IL-2. NHS-IL12 therapy significantly improved survival of sarcoma-bearing mice and caused long-term remissions when combined with IL-2. NHS-IL12 induced pronounced cancer cell senescence, as documented by strong expression of senescence-associated p16\(^{INK4a}\) and nuclear translocation of p-HP1γ, and permanent arrest of cancer cell proliferation. In addition, this cancer immunotherapy initiated the induction of myogenic differentiation, further promoting the hypothesis that efficient antitumor immunity includes mechanisms different from cytotoxicity for efficient cancer control in vivo.},
language = {en}
}
@article{SanzMorenoFuhrmannWolfetal.2014,
author = {Sanz-Moreno, Adrian and Fuhrmann, David and Wolf, Elmar and von Eyss, Bj{\"o}rn and Eilers, Martin and Els{\"a}sser, Hans-Peter},
title = {Miz1 Deficiency in the Mammary Gland Causes a Lactation Defect by Attenuated Stat5 Expression and Phosphorylation},
series = {PLOS ONE},
volume = {9},
journal = {PLOS ONE},
number = {2},
doi = {10.1371/journal.pone.0089187},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-117286},
pages = {e89187},
year = {2014},
abstract = {Miz1 is a zinc finger transcription factor with an N-terminal POZ domain. Complexes with Myc, Bcl-6 or Gfi-1 repress expression of genes like Cdkn2b (p15(Ink4)) or Cd-kn1a (p21(Cip1)). The role of Miz1 in normal mammary gland development has not been addressed so far. Conditional knockout of the Miz1 POZ domain in luminal cells during pregnancy caused a lactation defect with a transient reduction of glandular tissue, reduced proliferation and attenuated differentiation. This was recapitulated in vitro using mouse mammary gland derived HC11 cells. Further analysis revealed decreased Stat5 activity in Miz1 Delta POZ mammary glands and an attenuated expression of Stat5 targets. Gene expression of the Prolactin receptor (PrlR) and ErbB4, both critical for Stat5 phosphorylation (pStat5) or pStat5 nuclear translocation, was decreased in Miz1 Delta POZ females. Microarray, ChIP-Seq and gene set enrichment analysis revealed a down-regulation of Miz1 target genes being involved in vesicular transport processes. Our data suggest that deranged intracellular transport and localization of PrlR and ErbB4 disrupt the Stat5 signalling pathway in mutant glands and cause the observed lactation phenotype.},
language = {en}
}
@article{OhlebuschBorstFrankenbachetal.2020,
author = {Ohlebusch, Barbara and Borst, Angela and Frankenbach, Tina and Klopocki, Eva and Jakob, Franz and Liedtke, Daniel and Graser, Stephanie},
title = {Investigation of alpl expression and Tnap-activity in zebrafish implies conserved functions during skeletal and neuronal development},
series = {Scientific Reports},
volume = {10},
journal = {Scientific Reports},
doi = {10.1038/s41598-020-70152-5},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-230024},
year = {2020},
abstract = {Hypophosphatasia (HPP) is a rare genetic disease with diverse symptoms and a heterogeneous severity of onset with underlying mutations in the ALPL gene encoding the ectoenzyme Tissue-nonspecific alkaline phosphatase (TNAP). Considering the establishment of zebrafish (Danio rerio) as a new model organism for HPP, the aim of the study was the spatial and temporal analysis of alpl expression in embryos and adult brains. Additionally, we determined functional consequences of Tnap inhibition on neural and skeletal development in zebrafish. We show that expression of alpl is present during embryonic stages and in adult neuronal tissues. Analyses of enzyme function reveal zones of pronounced Tnap-activity within the telencephalon and the mesencephalon. Treatment of zebrafish embryos with chemical Tnap inhibitors followed by axonal and cartilage/mineralized tissue staining imply functional consequences of Tnap deficiency on neuronal and skeletal development. Based on the results from neuronal and skeletal tissue analyses, which demonstrate an evolutionary conserved role of this enzyme, we consider zebrafish as a promising species for modeling HPP in order to discover new potential therapy strategies in the long-term.},
language = {en}
}
@article{NolteZadehKhorasaniSafarovetal.2013,
author = {Nolte, Thomas and Zadeh-Khorasani, Maryam and Safarov, Orkhan and Rueff, Franziska and Varga, Rita and Herbach, Nadja and Wanke, R{\"u}diger and Wollenberg, Andreas and Mueller, Thomas and Gropp, Roswitha and Wolf, Eckhard and Siebeck, Matthias},
title = {Induction of oxazolone-mediated features of atopic dermatitis in NOD-scid IL2R \(γ^{null}\) mice engrafted with human peripheral blood mononuclear cells},
series = {Disease Models \& Mechanisms},
volume = {6},
journal = {Disease Models \& Mechanisms},
doi = {10.1242/dmm.009167},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-122189},
pages = {125-134},
year = {2013},
abstract = {Animal models mimicking human diseases have been used extensively to study the pathogenesis of autoimmune diseases and the efficacy of potential therapeutics. They are, however, limited with regard to their similarity to the human disease and cannot be used if the antagonist and its cognate receptor require high similarity in structure or binding. Here, we examine the induction of oxazolone-mediated features of atopic dermatitis (AD) in NOD-scid IL2R \(γ^{null}\) mice engrafted with human peripheral blood mononuclear cells (PBMC). The mice developed the same symptoms as immunocompetent BALB/c mice. Histological alterations induced by oxazolone were characterized by keratosis, epithelial hyperplasia and influx of inflammatory cells into the dermis and epidermis. The cellular infiltrate was identified as human leukocytes, with T cells being the major constituent. In addition, oxazolone increased human serum IgE levels. The response, however, required the engraftment of PBMC derived from patients suffering from AD, which suggests that this model reflects the immunological status of the donor. Taken together, the model described here has the potential to evaluate the efficacy of therapeutics targeting human lymphocytes in vivo and, in addition, might be developed further to elucidate molecular mechanisms inducing and sustaining flares of the disease.},
language = {en}
}
@article{KlotzMentrupRegensburgeretal.2012,
author = {Klotz, Barbara and Mentrup, Birgit and Regensburger, Martina and Zeck, Sabine and Schneidereit, Jutta and Schupp, Nicole and Linden, Christian and Merz, Cornelia and Ebert, Regina and Jakob, Franz},
title = {1,25-Dihydroxyvitamin D3 Treatment Delays Cellular Aging in Human Mesenchymal Stem Cells while Maintaining Their Multipotent Capacity},
series = {PLoS ONE},
volume = {7},
journal = {PLoS ONE},
number = {1},
doi = {10.1371/journal.pone.0029959},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133392},
pages = {e29959},
year = {2012},
abstract = {1,25-dihydroxyvitamin D3 (1,25D3) was reported to induce premature organismal aging in fibroblast growth factor-23 (Fgf23) and klotho deficient mice, which is of main interest as 1,25D3 supplementation of its precursor cholecalciferol is used in basic osteoporosis treatment. We wanted to know if 1,25D3 is able to modulate aging processes on a cellular level in human mesenchymal stem cells (hMSC). Effects of 100 nM 1,25D3 on hMSC were analyzed by cell proliferation and apoptosis assay, beta-galactosidase staining, VDR and surface marker immunocytochemistry, RT-PCR of 1,25D3-responsive, quiescence-and replicative senescence-associated genes. 1,25D3 treatment significantly inhibited hMSC proliferation and apoptosis after 72 h and delayed the development of replicative senescence in long-term cultures according to beta-galactosidase staining and P16 expression. Cell morphology changed from a fibroblast like appearance to broad and rounded shapes. Long term treatment did not induce lineage commitment in terms of osteogenic pathways but maintained their clonogenic capacity, their surface marker characteristics (expression of CD73, CD90, CD105) and their multipotency to develop towards the chondrogenic, adipogenic and osteogenic pathways. In conclusion, 1,25D3 delays replicative senescence in primary hMSC while the pro-aging effects seen in mouse models might mainly be due to elevated systemic phosphate levels, which propagate organismal aging.},
language = {en}
}
@article{KarlDandekar2015,
author = {Karl, Stefan and Dandekar, Thomas},
title = {Convergence behaviour and control in non-linear biological networks},
series = {Scientific Reports},
volume = {5},
journal = {Scientific Reports},
number = {09746},
doi = {10.1038/srep09746},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-148510},
year = {2015},
abstract = {Control of genetic regulatory networks is challenging to define and quantify. Previous control centrality metrics, which aim to capture the ability of individual nodes to control the system, have been found to suffer from plausibility and applicability problems. Here we present a new approach to control centrality based on network convergence behaviour, implemented as an extension of our genetic regulatory network simulation framework Jimena (http://stefan-karl.de/jimena). We distinguish three types of network control, and show how these mathematical concepts correspond to experimentally verified node functions and signalling pathways in immunity and cell differentiation: Total control centrality quantifies the impact of node mutations and identifies potential pharmacological targets such as genes involved in oncogenesis (e.g. zinc finger protein GLI2 or bone morphogenetic proteins in chondrocytes). Dynamic control centrality describes relaying functions as observed in signalling cascades (e.g. src kinase or Jak/Stat pathways). Value control centrality measures the direct influence of the value of the node on the network (e.g. Indian hedgehog as an essential regulator of proliferation in chondrocytes). Surveying random scale-free networks and biological networks, we find that control of the network resides in few high degree driver nodes and networks can be controlled best if they are sparsely connected.},
language = {en}
}
@article{HoennemannSanzMorenoWolfetal.2012,
author = {H{\"o}nnemann, Jan and Sanz-Moreno, Adrian and Wolf, Elmar and Eilers, Martin and Els{\"a}sser, Hans-Peter},
title = {Miz1 Is a Critical Repressor of cdkn1a during Skin Tumorigenesis},
series = {PLoS One},
volume = {7},
journal = {PLoS One},
number = {4},
doi = {10.1371/journal.pone.0034885},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133285},
pages = {e34885},
year = {2012},
abstract = {The transcription factor Miz1 forms repressive DNA-binding complexes with the Myc, Gfi-1 and Bcl-6 oncoproteins. Known target genes of these complexes encode the cyclin-dependent kinase inhibitors (CKIs) cdkn2b (p15\(^{Ink4}\)), cdkn1a (p21\(^{Cip1}\)), and cdkn1c (p57\(^{Kip2}\)). Whether Miz1-mediated repression is important for control of cell proliferation in vivo and for tumor formation is unknown. Here we show that deletion of the Miz1 POZ domain, which is critical for Miz1 function, restrains the development of skin tumors in a model of chemically-induced, Ras-dependent tumorigenesis. While the stem cell compartment appears unaffected, interfollicular keratinocytes lacking functional Miz1 exhibit a reduced proliferation and an accelerated differentiation of the epidermis in response to the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). Tumorigenesis, proliferation and normal differentiation are restored in animals lacking cdkn1a, but not in those lacking cdkn2b. Our data demonstrate that Miz1-mediated attenuation of cell cycle arrest pathways via repression of cdkn1a has a critical role during tumorigenesis in the skin.},
language = {en}
}
@article{HofgaardJodalBommertetal.2012,
author = {Hofgaard, Peter O. and Jodal, Henriette C. and Bommert, Kurt and Huard, Bertrand and Caers, Jo and Carlsen, Harald and Schwarzer, Rolf and Sch{\"u}nemann, Nicole and Jundt, Franziska and Lindeberg, Mona M. and Bogen, Bjarne},
title = {A Novel Mouse Model for Multiple Myeloma (MOPC315.BM) That Allows Noninvasive Spatiotemporal Detection of Osteolytic Disease},
series = {PLoS One},
volume = {7},
journal = {PLoS One},
number = {12},
doi = {10.1371/journal.pone.0051892},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131117},
pages = {e51892},
year = {2012},
abstract = {Multiple myeloma (MM) is a lethal human cancer characterized by a clonal expansion of malignant plasma cells in bone marrow. Mouse models of human MM are technically challenging and do not always recapitulate human disease. Therefore, new mouse models for MM are needed. Mineral-oil induced plasmacytomas (MOPC) develop in the peritoneal cavity of oil-injected BALB/c mice. However, MOPC typically grow extramedullary and are considered poor models of human MM. Here we describe an in vivo-selected MOPC315 variant, called MOPC315.BM, which can be maintained in vitro. When injected i.v. into BALB/c mice, MOPC315.BM cells exhibit tropism for bone marrow. As few as 10\(^4\) MOPC315.BM cells injected i.v. induced paraplegia, a sign of spinal cord compression, in all mice within 3-4 weeks. MOPC315.BM cells were stably transfected with either firefly luciferase (MOPC315.BM.Luc) or DsRed (MOPC315.BM.DsRed) for studies using noninvasive imaging. MOPC315.BM.Luc cells were detected in the tibiofemoral region already 1 hour after i.v. injection. Bone foci developed progressively, and as of day 5, MM cells were detected in multiple sites in the axial skeleton. Additionally, the spleen (a hematopoietic organ in the mouse) was invariably affected. Luminescent signals correlated with serum myeloma protein concentration, allowing for easy tracking of tumor load with noninvasive imaging. Affected mice developed osteolytic lesions. The MOPC315.BM model employs a common strain of immunocompetent mice (BALB/c) and replicates many characteristics of human MM. The model should be suitable for studies of bone marrow tropism, development of osteolytic lesions, drug testing, and immunotherapy in MM.},
language = {en}
}
@article{GmachBathePetersTeluguetal.2022,
author = {Gmach, Philipp and Bathe-Peters, Marc and Telugu, Narasimha and Miller, Duncan C. and Annibale, Paolo},
title = {Fluorescence spectroscopy of low-level endogenous β-adrenergic receptor expression at the plasma membrane of differentiating human iPSC-derived cardiomyocytes},
series = {International Journal of Molecular Sciences},
volume = {23},
journal = {International Journal of Molecular Sciences},
number = {18},
issn = {1422-0067},
doi = {10.3390/ijms231810405},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-288277},
year = {2022},
abstract = {The potential of human-induced pluripotent stem cells (hiPSCs) to be differentiated into cardiomyocytes (CMs) mimicking adult CMs functional morphology, marker genes and signaling characteristics has been investigated since over a decade. The evolution of the membrane localization of CM-specific G protein-coupled receptors throughout differentiation has received, however, only limited attention to date. We employ here advanced fluorescent spectroscopy, namely linescan Fluorescence Correlation Spectroscopy (FCS), to observe how the plasma membrane abundance of the β\(_1\)- and β\(_2\)-adrenergic receptors (β\(_{1/2}\)-ARs), labelled using a bright and photostable fluorescent antagonist, evolves during the long-term monolayer culture of hiPSC-derived CMs. We compare it to the kinetics of observed mRNA levels in wildtype (WT) hiPSCs and in two CRISPR/Cas9 knock-in clones. We conduct these observations against the backdrop of our recent report of cell-to-cell expression variability, as well as of the subcellular localization heterogeneity of β-ARs in adult CMs.},
language = {en}
}
@article{DegenkolbeKoenigZimmeretal.2013,
author = {Degenkolbe, Elisa and K{\"o}nig, Jana and Zimmer, Julia and Walther, Maria and Reißner, Carsten and Nickel, Joachim and Pl{\"o}ger, Frank and Raspopovic, Jelena and Sharpe, James and Dathe, Katharina and Hecht, Jacqueline T. and Mundlos, Stefan and Doelken, Sandra C. and Seemann, Petra},
title = {A GDF5 Point Mutation Strikes Twice - Causing BDA1 and SYNS2},
series = {PLOS Genetics},
volume = {9},
journal = {PLOS Genetics},
number = {10},
issn = {1553-7404},
doi = {10.1371/journal.pgen.1003846},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-127556},
pages = {e1003846},
year = {2013},
abstract = {Growth and Differentiation Factor 5 (GDF5) is a secreted growth factor that belongs to the Bone Morphogenetic Protein (BMP) family and plays a pivotal role during limb development. GDF5 is a susceptibility gene for osteoarthritis (OA) and mutations in GDF5 are associated with a wide variety of skeletal malformations ranging from complex syndromes such as acromesomelic chondrodysplasias to isolated forms of brachydactylies or multiple synostoses syndrome 2 (SYNS2). Here, we report on a family with an autosomal dominant inherited combination of SYNS2 and additional brachydactyly type A1 (BDA1) caused by a single point mutation in GDF5 (p.W414R). Functional studies, including chondrogenesis assays with primary mesenchymal cells, luciferase reporter gene assays and Surface Plasmon Resonance analysis, of the GDF5 W-414R variant in comparison to other GDF5 mutations associated with isolated BDA1 (p.R399C) or SYNS2 (p.E491K) revealed a dual pathomechanism characterized by a gain-and loss-of-function at the same time. On the one hand insensitivity to the main GDF5 antagonist NOGGIN (NOG) leads to a GDF5 gain of function and subsequent SYNS2 phenotype. Whereas on the other hand, a reduced signaling activity, specifically via the BMP receptor type IA (BMPR1A), is likely responsible for the BDA1 phenotype. These results demonstrate that one mutation in the overlapping interface of antagonist and receptor binding site in GDF5 can lead to a GDF5 variant with pathophysiological relevance for both, BDA1 and SYNS2 development. Consequently, our study assembles another part of the molecular puzzle of how loss and gain of function mutations in GDF5 affect bone development in hands and feet resulting in specific types of brachydactyly and SYNS2. These novel insights into the biology of GDF5 might also provide further clues on the pathophysiology of OA.},
language = {en}
}
@article{CaiElMerahbiLoeffleretal.2017,
author = {Cai, Kai and El-Merahbi, Rabih and Loeffler, Mona and Mayer, Alexander E. and Sumara, Grzegorz},
title = {Ndrg1 promotes adipocyte differentiation and sustains their function},
series = {Scientific Reports},
volume = {7},
journal = {Scientific Reports},
number = {7191},
doi = {10.1038/s41598-017-07497-x},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170565},
year = {2017},
abstract = {Adipocytes play a central role in maintaining metabolic homeostasis in the body. Differentiation of adipocyte precursor cells requires the transcriptional activity of peroxisome proliferator-activated receptor-γ (Pparγ) and CCAAT/enhancer binding proteins (C/Ebps). Transcriptional activity is regulated by signaling modules activated by a plethora of hormones and nutrients. Mechanistic target of rapamacin complexes (mTORC) 1 and 2 are central for the coordination of hormonal and nutritional inputs in cells and are essential for adipogenesis. Serum glucocorticoid kinase 1 (Sgk1)-dependent phosphorylation of N-Myc downstream-regulated gene 1 (Ndrg1) is a hallmark of mTORC2 activation in cells. Moreover, Pparγ activation promotes Ndrg1 expression. However, the impact of Ndrg1 on adipocyte differentiation and function has not yet been defined. Here, we show that Ndrg1 expression and its Sgk1-dependent phosphorylation are induced during adipogenesis. Consistently, we demonstrate that Ndrg1 promotes adipocyte differentiation and function by inducing Pparγ expression. Additionally, our results indicate that Ndrg1 is required for C/Ebpα phosphorylation. Moreover, we found that Ndrg1 phosphorylation by Sgk1 promotes adipocyte formation. Taken together, we show that induction of Ndrg1 expression by Pparγ and its phosphorylation by Sgk1 kinase are required for the acquisition of adipocyte characteristics by precursor cells.},
language = {en}
}
@article{BugaScholzKumaretal.2012,
author = {Buga, Ana-Maria and Scholz, Claus J{\"u}rgen and Kumar, Senthil and Herndon, James G. and Alexandru, Dragos and Cojocaru, Gabriel Radu and Dandekar, Thomas and Popa-Wagner, Aurel},
title = {Identification of New Therapeutic Targets by Genome-Wide Analysis of Gene Expression in the Ipsilateral Cortex of Aged Rats after Stroke},
series = {PLoS One},
volume = {7},
journal = {PLoS One},
number = {12},
doi = {10.1371/journal.pone.0050985},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130657},
pages = {e50985},
year = {2012},
abstract = {Background: Because most human stroke victims are elderly, studies of experimental stroke in the aged rather than the young rat model may be optimal for identifying clinically relevant cellular responses, as well for pinpointing beneficial interventions. Methodology/Principal Findings: We employed the Affymetrix platform to analyze the whole-gene transcriptome following temporary ligation of the middle cerebral artery in aged and young rats. The correspondence, heat map, and dendrogram analyses independently suggest a differential, age-group-specific behaviour of major gene clusters after stroke. Overall, the pattern of gene expression strongly suggests that the response of the aged rat brain is qualitatively rather than quantitatively different from the young, i.e. the total number of regulated genes is comparable in the two age groups, but the aged rats had great difficulty in mounting a timely response to stroke. Our study indicates that four genes related to neuropathic syndrome, stress, anxiety disorders and depression (Acvr1c, Cort, Htr2b and Pnoc) may have impaired response to stroke in aged rats. New therapeutic options in aged rats may also include Calcrl, Cyp11b1, Prcp, Cebpa, Cfd, Gpnmb, Fcgr2b, Fcgr3a, Tnfrsf26, Adam 17 and Mmp14. An unexpected target is the enzyme 3-hydroxy-3-methylglutaryl-Coenzyme A synthase 1 in aged rats, a key enzyme in the cholesterol synthesis pathway. Post-stroke axonal growth was compromised in both age groups. Conclusion/Significance: We suggest that a multi-stage, multimodal treatment in aged animals may be more likely to produce positive results. Such a therapeutic approach should be focused on tissue restoration but should also address other aspects of patient post-stroke therapy such as neuropathic syndrome, stress, anxiety disorders, depression, neurotransmission and blood pressure.},
language = {en}
}
@article{BarnekowGessler1986,
author = {Barnekow, Angelika and Gessler, Manfred},
title = {Activation of the pp60\(^{c-src}\) kinase during differentiation of monomyelocytic cells in vitro},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59278},
year = {1986},
abstract = {Tbe proto-oncogene c-src, the cellular homolog of the Rous sarcoma virus (RSV) transforming gene v-src, is expressed in a tissue-specific and age-dependent manner. Its physiological function, although still unknown, appears to be more closely related to differentiation processes than to proliferation processes. To obtain more information about the physiological role of the c-src gene in cells, we have studied differentiation-dependent alterations using the human HL-60 leukaemia cell line as a model system. Induction of monocytic and granulocytic differentiation of HL-60 cells by 12-0-tetradecanoylphorbol-13-acetate (TPA) and dimethylsulfoxide (DMSO) is associated with an activation of the pp60c-src tyrosine kinase, but not with increased c-src gene expression. Control experiments exclude an interaction of TPA and DMSO themselves with the pp60c-src kinase.},
subject = {Biochemie},
language = {en}
}
@article{AhmadWolberEckardtetal.2012,
author = {Ahmad, Ruhel and Wolber, Wanja and Eckardt, Sigrid and Koch, Philipp and Schmitt, Jessica and Semechkin, Ruslan and Geis, Christian and Heckmann, Manfred and Br{\"u}stle, Oliver and McLaughlin, John K. and Sir{\´e}n, Anna-Leena and M{\"u}ller, Albrecht M.},
title = {Functional Neuronal Cells Generated by Human Parthenogenetic Stem Cells},
series = {PLoS One},
volume = {7},
journal = {PLoS One},
number = {8},
doi = {10.1371/journal.pone.0042800},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130268},
pages = {e42800},
year = {2012},
abstract = {Parent of origin imprints on the genome have been implicated in the regulation of neural cell type differentiation. The ability of human parthenogenetic (PG) embryonic stem cells (hpESCs) to undergo neural lineage and cell type-specific differentiation is undefined. We determined the potential of hpESCs to differentiate into various neural subtypes. Concurrently, we examined DNA methylation and expression status of imprinted genes. Under culture conditions promoting neural differentiation, hpESC-derived neural stem cells (hpNSCs) gave rise to glia and neuron-like cells that expressed subtype-specific markers and generated action potentials. Analysis of imprinting in hpESCs and in hpNSCs revealed that maternal-specific gene expression patterns and imprinting marks were generally maintained in PG cells upon differentiation. Our results demonstrate that despite the lack of a paternal genome, hpESCs generate proliferating NSCs that are capable of differentiation into physiologically functional neuron-like cells and maintain allele-specific expression of imprinted genes. Thus, hpESCs can serve as a model to study the role of maternal and paternal genomes in neural development and to better understand imprinting-associated brain diseases.},
language = {en}
}