TY - JOUR A1 - Palamides, Pia A1 - Jodeleit, Henrika A1 - Föhlinger, Michael A1 - Beigel, Florian A1 - Herbach, Nadja A1 - Mueller, Thomas A1 - Wolf, Eckhard A1 - Siebeck, Matthias A1 - Gropp, Roswitha T1 - A mouse model for ulcerative colitis based on NOD-scid IL2R gamma(null) mice reconstituted with peripheral blood mononuclear cells from affected individuals JF - Disease Models & Mechanisms N2 - Animal models reflective of ulcerative colitis (UC) remain a major challenge, and yet are crucial to understand mechanisms underlying the onset of disease and inflammatory characteristics of relapses and remission. Mouse models in which colitis-like symptoms are induced through challenge with toxins such as oxazolone, dextran sodium sulfate (DSS) or 2,4,6-trinitrobenzenesulfonic acid (TNBS) have been instrumental in understanding the inflammatory processes of UC. However, these neither reflect the heterogeneous symptoms observed in the UC-affected population nor can they be used to test the efficacy of inhibitors developed against human targets where high sequence and structural similarity of the respective ligands is lacking. In an attempt to overcome these problems, we have developed a mouse model that relies on NOD-scid IL2R γnull mice reconstituted with peripheral blood mononuclear cells derived from UC-affected individuals. Upon challenge with ethanol, mice developed colitis-like symptoms and changes in the colon architecture, characterized by influx of inflammatory cells, edema, crypt loss, crypt abscesses and epithelial hyperplasia, as previously observed in immune-competent mice. TARC, TGFβ1 and HGF expression increased in distal parts of the colon. Analysis of human leucocytes isolated from mouse spleen revealed an increase in frequencies of CD1a+, CD64+, CD163+ and TSLPR+ CD14+ monocytes, and antigen-experienced CD44+ CD4+ and CD8+ T-cells in response to ethanol. Analysis of human leucocytes from the colon of challenged mice identified CD14+ monocytes and CD11b+ monocytes as the predominant populations. Quantitative real-time PCR (RT-PCR) analysis from distal parts of the colon indicated that IFNγ might be one of the cytokines driving inflammation. Treatment with infliximab ameliorated symptoms and pathological manifestations, whereas pitrakinra had no therapeutic benefit. Thus, this model is partially reflective of the human disease and might help to increase the translation of animal and clinical studies. KW - animal models KW - Ulcerative colitis KW - NSG mice KW - Infliximab KW - Pitrakinra Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-164946 VL - 9 ER - TY - JOUR A1 - Seher, Axel A1 - Nickel, Joachim A1 - Mueller, Thomas D. A1 - Kneitz, Susanne A1 - Gebhardt, Susanne A1 - Meyer ter Vehn, Tobias A1 - Schlunck, Guenther A1 - Sebald, Walter T1 - Gene expression profiling of connective tissue growth factor (CTGF) stimulated primary human tenon fibroblasts reveals an inflammatory and wound healing response in vitro JF - Molecular Vision N2 - Purpose: The biologic relevance of human connective tissue growth factor (hCTGF) for primary human tenon fibroblasts (HTFs) was investigated by RNA expression profiling using affymetrix (TM) oligonucleotide array technology to identify genes that are regulated by hCTGF. Methods: Recombinant hCTGF was expressed in HEK293T cells and purified by affinity and gel chromatography. Specificity and biologic activity of hCTGF was confirmed by biosensor interaction analysis and proliferation assays. For RNA expression profiling HTFs were stimulated with hCTGF for 48h and analyzed using affymetrix (TM) oligonucleotide array technology. Results were validated by real time RT-PCR. Results: hCTGF induces various groups of genes responsible for a wound healing and inflammatory response in HTFs. A new subset of CTGF inducible inflammatory genes was discovered (e.g., chemokine [C-X-C motif] ligand 1 [CXCL1], chemokine [C-X-C motif] ligand 6 [CXCL6], interleukin 6 [IL6], and interleukin 8 [IL8]). We also identified genes that can transmit the known biologic functions initiated by CTGF such as proliferation and extracellular matrix remodelling. Of special interest is a group of genes, e.g., osteoglycin (OGN) and osteomodulin (OMD), which are known to play a key role in osteoblast biology. Conclusions: This study specifies the important role of hCTGF for primary tenon fibroblast function. The RNA expression profile yields new insights into the relevance of hCTGF in influencing biologic processes like wound healing, inflammation, proliferation, and extracellular matrix remodelling in vitro via transcriptional regulation of specific genes. The results suggest that CTGF potentially acts as a modulating factor in inflammatory and wound healing response in fibroblasts of the human eye. KW - Bone morphogenetic protein-2 KW - Smooth-muscle-cells KW - Myofibroblast differentiation KW - TGF-beta KW - CYR61 KW - Proliferation KW - Mechanisms KW - Apoptosis KW - Receptor KW - Cancer Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-140189 VL - 17 IS - 08. Okt ER - TY - JOUR A1 - Keller, Alexander A1 - Foerster, Frank A1 - Mueller, Tobias A1 - Dandekar, Thomas A1 - Schultz, Joerg A1 - Wolf, Matthias T1 - Including RNA secondary structures improves accuracy and robustness in reconstruction of phylogenetic trees N2 - Background: In several studies, secondary structures of ribosomal genes have been used to improve the quality of phylogenetic reconstructions. An extensive evaluation of the benefits of secondary structure, however, is lacking. Results: This is the first study to counter this deficiency. We inspected the accuracy and robustness of phylogenetics with individual secondary structures by simulation experiments for artificial tree topologies with up to 18 taxa and for divergency levels in the range of typical phylogenetic studies. We chose the internal transcribed spacer 2 of the ribosomal cistron as an exemplary marker region. Simulation integrated the coevolution process of sequences with secondary structures. Additionally, the phylogenetic power of marker size duplication was investigated and compared with sequence and sequence-structure reconstruction methods. The results clearly show that accuracy and robustness of Neighbor Joining trees are largely improved by structural information in contrast to sequence only data, whereas a doubled marker size only accounts for robustness. Conclusions: Individual secondary structures of ribosomal RNA sequences provide a valuable gain of information content that is useful for phylogenetics. Thus, the usage of ITS2 sequence together with secondary structure for taxonomic inferences is recommended. Other reconstruction methods as maximum likelihood, bayesian inference or maximum parsimony may equally profit from secondary structure inclusion. Reviewers: This article was reviewed by Shamil Sunyaev, Andrea Tanzer (nominated by Frank Eisenhaber) and Eugene V. Koonin. Open peer review: Reviewed by Shamil Sunyaev, Andrea Tanzer (nominated by Frank Eisenhaber) and Eugene V. Koonin. For the full reviews, please go to the Reviewers’ comments section. KW - Phylogenie KW - phylogenetics Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-67832 ER - TY - JOUR A1 - Friedrich, Torben A1 - Rahmann, Sven A1 - Weigel, Wilfried A1 - Rabsch, Wolfgang A1 - Fruth, Angelika A1 - Ron, Eliora A1 - Gunzer, Florian A1 - Dandekar, Thomas A1 - Hacker, Joerg A1 - Mueller, Tobias A1 - Dobrindt, Ulrich T1 - High-throughput microarray technology in diagnostics of enterobacteria based on genome-wide probe selection and regression analysis N2 - The Enterobacteriaceae comprise a large number of clinically relevant species with several individual subspecies. Overlapping virulence-associated gene pools and the high overall genome plasticity often interferes with correct enterobacterial strain typing and risk assessment. Array technology offers a fast, reproducible and standardisable means for bacterial typing and thus provides many advantages for bacterial diagnostics, risk assessment and surveillance. The development of highly discriminative broad-range microbial diagnostic microarrays remains a challenge, because of marked genome plasticity of many bacterial pathogens. Results: We developed a DNA microarray for strain typing and detection of major antimicrobial resistance genes of clinically relevant enterobacteria. For this purpose, we applied a global genome-wide probe selection strategy on 32 available complete enterobacterial genomes combined with a regression model for pathogen classification. The discriminative power of the probe set was further tested in silico on 15 additional complete enterobacterial genome sequences. DNA microarrays based on the selected probes were used to type 92 clinical enterobacterial isolates. Phenotypic tests confirmed the array-based typing results and corroborate that the selected probes allowed correct typing and prediction of major antibiotic resistances of clinically relevant Enterobacteriaceae, including the subspecies level, e.g. the reliable distinction of different E. coli pathotypes. Conclusions: Our results demonstrate that the global probe selection approach based on longest common factor statistics as well as the design of a DNA microarray with a restricted set of discriminative probes enables robust discrimination of different enterobacterial variants and represents a proof of concept that can be adopted for diagnostics of a wide range of microbial pathogens. Our approach circumvents misclassifications arising from the application of virulence markers, which are highly affected by horizontal gene transfer. Moreover, a broad range of pathogens have been covered by an efficient probe set size enabling the design of high-throughput diagnostics. KW - Mikroarray KW - Enterobacteriaceae Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-67936 ER - TY - JOUR A1 - Monzon-Casanova, Elisa A1 - Steiniger, Birte A1 - Schweigle, Stefanie A1 - Clemen, Holger A1 - Zdzieblo, Daniela A1 - Starick, Lisa A1 - Mueller, Ingrid A1 - Wang, Chyung-Ru A1 - Rhost, Sara A1 - Cardell, Susanna A1 - Pyz, Elwira A1 - Herrmann, Thomas T1 - CD1d Expression in Paneth Cells and Rat Exocrine Pancreas Revealed by Novel Monoclonal Antibodies Which Differentially Affect NKT Cell Activation N2 - Background: CD1d is a nonpolymorphic MHC class I-like molecule which presents nonpeptide ligands, e.g. glycolipids, to NKT cells. These cells are known to have multiple effects on innate and adaptive immune responses and on the development of pathological conditions. In order to analyze CD1d expression and function in the rat, the first rat CD1dspecific monoclonal antibodies (mAbs) were generated. Methodology/Principal Findings: Two mAbs, WTH-1 and WTH-2, were generated which bound equally well to cell surfaceexpressed rat and mouse CD1d. Their non-overlapping epitopes were mapped to the CD1d heavy chain. Flow cytometry and immunohistological analyses revealed a nearly identical degree and pattern of CD1d expression for hematopoieitic cells of both species. Notable is also the detection of CD1d protein in mouse and rat Paneth cells as well as the extremely high CD1d expression in acinar exocrine cells of the rat pancreas and the expression of CD4 on rat marginal zone B cells. Both mAbs blocked a-galactosylceramide recognition by primary rat and mouse NKT cells. Interestingly, the two mAbs differed in their impact on the activation of various autoreactive T cell hybridomas, including the XV19.2 hybridoma whose activation was enhanced by the WTH-1 mAb. Conclusions/Significance: The two novel monoclonal antibodies described in this study, allowed the analysis of CD1d expression and CD1d-restricted T cell responses in the rat for the first time. Moreover, they provided new insights into mechanisms of CD1d-restricted antigen recognition. While CD1d expression by hematopoietic cells of mice and rats was extremely similar, CD1d protein was detected at not yet described sites of non-lymphatic tissues such as the rat exocrine pancreas and Paneth cells. The latter is of special relevance given the recently reported defects of Paneth cells in CD1d2/2 mice, which resulted in an altered composition of the gut flora. KW - Krebs Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-68477 ER - TY - JOUR A1 - Harth, Stefan A1 - Kotzsch, Alexander A1 - Hu, Junli A1 - Sebald, Walter A1 - Mueller, Thomas D. T1 - A Selection Fit Mechanism in BMP Receptor IA as a Possible Source for BMP Ligand-Receptor Promiscuity N2 - Background: Members of the TGF-b superfamily are characterized by a highly promiscuous ligand-receptor interaction as is readily apparent from the numeral discrepancy of only seven type I and five type II receptors available for more than 40 ligands. Structural and functional studies have been used to address the question of how specific signals can be deduced from a limited number of receptor combinations and to unravel the molecular mechanisms underlying the protein-protein recognition that allow such limited specificity. Principal Findings: In this study we have investigated how an antigen binding antibody fragment (Fab) raised against the extracellular domain of the BMP receptor type IA (BMPR-IA) recognizes the receptor’s BMP-2 binding epitope and thereby neutralizes BMP-2 receptor activation. The crystal structure of the complex of the BMPR-IA ectodomain bound to the Fab AbD1556 revealed that the contact surface of BMPR-IA overlaps extensively with the contact surface for BMP-2 interaction. Although the structural epitopes of BMPR-IA to both binding partners coincides, the structures of BMPR-IA in the two complexes differ significantly. In contrast to the structural differences, alanine-scanning mutagenesis of BMPR-IA showed that the functional determinants for binding to the antibody and BMP-2 are almost identical. Conclusions: Comparing the structures of BMPR-IA bound to BMP-2 or bound to the Fab AbD1556 with the structure of unbound BMPR-IA shows that binding of BMPR-IA to its interaction partners follows a selection fit mechanism, possibly indicating that the ligand promiscuity of BMPR-IA is inherently encoded by structural adaptability. The functional and structural analysis of the BMPR-IA binding antibody AbD1556 mimicking the BMP-2 binding epitope may thus pave the way for the design of low-molecular weight synthetic receptor binders/inhibitors. KW - Physiologische Chemie KW - antigen binding antibody fragment (Fab) Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-68497 ER - TY - JOUR A1 - Mueller, Kerstin A1 - Quandt, Jasmin A1 - Marienfeld, Ralf B. A1 - Weihrich, Petra A1 - Fiedler, Katja A1 - Claussnitzer, Melina A1 - Laumen, Helmut A1 - Vaeth, Martin A1 - Berberich-Siebelt, Frederike A1 - Serfling, Edgar A1 - Wirth, Thomas A1 - Brunner, Cornelia T1 - Octamer-dependent transcription in T cells is mediated by NFAT and \(NF-\kappa B\) JF - Nucleic Acids Research N2 - The transcriptional co-activator BOB.1/OBF.1 was originally identified in B cells and is constitutively expressed throughout B cell development. BOB.1/OBF.1 associates with the transcription factors Oct1 and Oct2, thereby enhancing octamer-dependent transcription. In contrast, in T cells, BOB.1/OBF.1 expression is inducible by treatment of cells with PMA/Ionomycin or by antigen receptor engagement, indicating a marked difference in the regulation of BOB.1/OBF.1 expression in B versus T cells. The molecular mechanisms underlying the differential expression of BOB.1/OBF.1 in T and B cells remain largely unknown. Therefore, the present study focuses on mechanisms controlling the transcriptional regulation of BOB.1/OBF.1 and Oct2 in T cells. We show that both calcineurin- and \(NF-\kappa B\)-inhibitors efficiently attenuate the expression of BOB.1/OBF.1 and Oct2 in T cells. In silico analyses of the BOB.1/OBF.1 promoter revealed the presence of previously unappreciated combined NFAT/\(NF-\kappa B\) sites. An array of genetic and biochemical analyses illustrates the involvement of the \(Ca^{2+}\)/calmodulin-dependent phosphatase calcineurin as well as NFAT and \(NF-\kappa B\) transcription factors in the transcriptional regulation of octamer-dependent transcription in T cells. Conclusively, impaired expression of BOB.1/OBF.1 and Oct2 and therefore a hampered octamer-dependent transcription may participate in T cell-mediated immunodeficiency caused by the deletion of NFAT or \(NF-\kappa B\) transcription factors. KW - germinal center formation KW - OBF-1 OCA-B KW - coactivator OBF-1 KW - gene expression KW - functional characterization KW - immunoglobulin promoters KW - OCT-1-deficient mice KW - embryonic lethality KW - endothelial cells KW - murine homolog Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-123280 SN - 1362-4962 VL - 41 IS - 4 ER - TY - JOUR A1 - Böhm, Jennifer A1 - Scherzer, Sönke A1 - Krol, Elzbieta A1 - Kreuzer, Ines A1 - von Meyer, Katharina A1 - Lorey, Christian A1 - Mueller, Thomas D. A1 - Shabala, Lana A1 - Monte, Isabel A1 - Salano, Roberto A1 - Al-Rasheid, Khaled A. S. A1 - Rennenberg, Heinz A1 - Shabala, Sergey A1 - Neher, Erwin A1 - Hedrich, Rainer T1 - The Venus Flytrap Dionaea muscipula Counts Prey-Induced Action Potentials to Induce Sodium Uptake JF - Current Biology N2 - Carnivorous plants, such as the Venus flytrap (Dionaea muscipula), depend on an animal diet when grown in nutrient-poor soils. When an insect visits the trap and tilts the mechanosensors on the inner surface, action potentials (APs) are fired. After a moving object elicits two APs, the trap snaps shut, encaging the victim. Panicking preys repeatedly touch the trigger hairs over the subsequent hours, leading to a hermetically closed trap, which via the gland-based endocrine system is flooded by a prey-decomposing acidic enzyme cocktail. Here, we asked the question as to how many times trigger hairs have to be stimulated (e.g., now many APs are required) for the flytrap to recognize an encaged object as potential food, thus making it worthwhile activating the glands. By applying a series of trigger-hair stimulations, we found that the touch hormone jasmonic acid (JA) signaling pathway is activated after the second stimulus, while more than three APs are required to trigger an expression of genes encoding prey-degrading hydrolases, and that this expression is proportional to the number of mechanical stimulations. A decomposing animal contains a sodium load, and we have found that these sodium ions enter the capture organ via glands. We identified a flytrap sodium channel DmHKT1 as responsible for this sodium acquisition, with the number of transcripts expressed being dependent on the number of mechano-electric stimulations. Hence, the number of APs a victim triggers while trying to break out of the trap identifies the moving prey as a struggling Na+-rich animal and nutrition for the plant. KW - Venusfliegenfalle KW - Dionaea muscipula Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-128054 VL - 26 IS - 3 ER - TY - JOUR A1 - Diestel, Uschi A1 - Resch, Marcus A1 - Meinhardt, Kathrin A1 - Weiler, Sigrid A1 - Hellmann, Tina V. A1 - Mueller, Thomas D. A1 - Nickel, Joachim A1 - Eichler, Jutta A1 - Muller, Yves A. T1 - Identification of a Novel TGF-beta-Binding Site in the Zona Pellucida C-terminal (ZP-C) Domain of TGF-\(\beta\)-Receptor-3 (TGFR-3) JF - PLoS ONE N2 - The zona pellucida (ZP) domain is present in extracellular proteins such as the zona pellucida proteins and tectorins and participates in the formation of polymeric protein networks. However, the ZP domain also occurs in the cytokine signaling co-receptor transforming growth factor beta (TGF-\(\beta\)) receptor type 3 (TGFR-3, also known as betaglycan) where it contributes to cytokine ligand recognition. Currently it is unclear how the ZP domain architecture enables this dual functionality. Here, we identify a novel major TGF-beta-binding site in the FG loop of the C-terminal subdomain of the murine TGFR-3 ZP domain (ZP-C) using protein crystallography, limited proteolysis experiments, surface plasmon resonance measurements and synthetic peptides. In the murine 2.7 angstrom crystal structure that we are presenting here, the FG-loop is disordered, however, well-ordered in a recently reported homologous rat ZP-C structure. Surprisingly, the adjacent external hydrophobic patch (EHP) segment is registered differently in the rat and murine structures suggesting that this segment only loosely associates with the remaining ZP-C fold. Such a flexible and temporarily-modulated association of the EHP segment with the ZP domain has been proposed to control the polymerization of ZP domain-containing proteins. Our findings suggest that this flexibility also extends to the ZP domain of TGFR-3 and might facilitate co-receptor ligand interaction and presentation via the adjacent FG-loop. This hints that a similar C-terminal region of the ZP domain architecture possibly regulates both the polymerization of extracellular matrix proteins and cytokine ligand recognition of TGFR-3. KW - coreceptor KW - receptor type III KW - growth factor beta KW - ligand binding KW - betaglycan KW - proteins KW - mutagenesis KW - polymerization KW - glycoprotein KW - superfamily Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-130904 VL - 8 IS - 6 ER - TY - JOUR A1 - Boschert, Verena A1 - van Dinther, Maarten A1 - Weidauer, Stella A1 - van Pee, Katharina A1 - Muth, Eva-Maria A1 - ten Dijke, Peter A1 - Mueller, Thomas D. T1 - Mutational Analysis of Sclerostin Shows Importance of the Flexible Loop and the Cystine-Knot for Wnt-Signaling Inhibition JF - PLoS ONE N2 - The cystine-knot containing protein Sclerostin is an important negative regulator of bone growth and therefore represents a promising therapeutic target. It exerts its biological task by inhibiting the Wnt (wingless and int1) signaling pathway, which participates in bone formation by promoting the differentiation of mesenchymal stem cells to osteoblasts. The core structure of Sclerostin consists of three loops with the first and third loop (Finger 1 and Finger 2) forming a structured \(\beta\)-sheet and the second loop being unstructured and highly flexible. Biochemical data showed that the flexible loop is important for binding of Sclerostin to Wnt co-receptors of the low-density lipoprotein related-protein family (LRP), by interacting with the Wnt co-receptors LRP5 or -6 it inhibits Wnt signaling. To further examine the structural requirements for Wnt inhibition, we performed an extensive mutational study within all three loops of the Sclerostin core domain involving single and multiple mutations as well as truncation of important regions. By this approach we could confirm the importance of the second loop and especially of amino acids Asn92 and Ile94 for binding to LRP6. Based on a Sclerostin variant found in a Turkish family suffering from Sclerosteosis we generated a Sclerostin mutant with cysteines 84 and 142 exchanged thereby removing the third disulfide bond of the cystine-knot. This mutant binds to LRP6 with reduced binding affinity and also exhibits a strongly reduced inhibitory activity against Wnt1 thereby showing that also elements outside the flexible loop are important for inhibition of Wnt by Sclerostin. Additionally, we examined the effect of the mutations on the inhibition of two different Wnt proteins, Wnt3a and Wnt1. We could detect clear differences in the inhibition of these proteins, suggesting that the mechanism by which Sclerostin antagonizes Wnt1 and Wnt3a is fundamentally different. KW - Wnt signaling cascade KW - binding analysis KW - osteoblasts KW - sequence motif analysis KW - biological locomotion KW - signal inhibition KW - cell binding assay KW - luciferase Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-129862 VL - 8 IS - 11 ER - TY - JOUR A1 - Mueller, Thomas D. A1 - Fiebig, Juliane E. A1 - Weidauer, Stella E. A1 - Qiu, Li-Yan A1 - Bauer, Markus A1 - Schmieder, Peter A1 - Beerbaum, Monika A1 - Zhang, Jin-Li A1 - Oschkinat, Hartmut A1 - Sebald, Walter T1 - The Clip-Segment of the von Willebrand Domain 1 of the BMP Modulator Protein Crossveinless 2 Is Preformed JF - Molecules N2 - Bone Morphogenetic Proteins (BMPs) are secreted protein hormones that act as morphogens and exert essential roles during embryonic development of tissues and organs. Signaling by BMPs occurs via hetero-oligomerization of two types of serine/threonine kinase transmembrane receptors. Due to the small number of available receptors for a large number of BMP ligands ligand-receptor promiscuity presents an evident problem requiring additional regulatory mechanisms for ligand-specific signaling. Such additional regulation is achieved through a plethora of extracellular antagonists, among them members of the Chordin superfamily, that modulate BMP signaling activity by binding. The key-element in Chordin-related antagonists for interacting with BMPs is the von Willebrand type C (VWC) module, which is a small domain of about 50 to 60 residues occurring in many different proteins. Although a structure of the VWC domain of the Chordin-member Crossveinless 2 (CV2) bound to BMP-2 has been determined by X-ray crystallography, the molecular mechanism by which the VWC domain binds BMPs has remained unclear. Here we present the NMR structure of the Danio rerio CV2 VWC1 domain in its unbound state showing that the key features for high affinity binding to BMP-2 is a pre-oriented peptide loop. KW - bone morphogenetic proteins KW - TGF-β superfamily KW - BMP antagonist KW - protein-protein recognition KW - NMR spectroscopy KW - von Willebrand type C domain Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-97196 ER - TY - JOUR A1 - Schleicher, Bernd A1 - Arbet-Engels, Axel A1 - Baack, Dominik A1 - Balbo, Matteo A1 - Biland, Adrian A1 - Blank, Michael A1 - Bretz, Thomas A1 - Bruegge, Kai A1 - Bulinski, Michael A1 - Buss, Jens A1 - Doerr, Manuel A1 - Dorner, Daniela A1 - Elsaesser, Dominik A1 - Grischagin, Sergej A1 - Hildebrand, Dorothee A1 - Linhoff, Lena A1 - Mannheim, Karl A1 - Mueller, Sebastian Achim A1 - Neise, Dominik A1 - Neronov, Andrii A1 - Noethe, Maximilian A1 - Paravac, Aleksander A1 - Rhode, Wolfgang A1 - Schulz, Florian A1 - Sedlaczek, Kevin A1 - Shukla, Amit A1 - Sliusar, Vitalii A1 - Willert, Elan A1 - Walter, Roland T1 - Fractional Variability—A Tool to Study Blazar Variability JF - Galaxies N2 - Active Galactic Nuclei emit radiation over the whole electromagnetic spectrum up to TeV energies. Blazars are one subtype with their jets pointing towards the observer. One of their typical features is extreme variability on timescales, from minutes to years. The fractional variability is an often used parameter for investigating the degree of variability of a light curve. Different detection methods and sensitivities of the instruments result in differently binned data and light curves with gaps. As they can influence the physics interpretation of the broadband variability, the effects of these differences on the fractional variability need to be studied. In this paper, we study the systematic effects of completeness in time coverage and the sampling rate. Using public data from instruments monitoring blazars in various energy ranges, we study the variability of the bright TeV blazars Mrk 421 and Mrk 501 over the electromagnetic spectrum, taking into account the systematic effects, and compare our findings with previous results. Especially in the TeV range, the fractional variability is higher than in previous studies, which can be explained by the much longer (seven years compared to few weeks) and more complete data sample. KW - blazars KW - variability KW - fractional variability KW - active galactic nuclei Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-197348 SN - 2075-4434 VL - 7 IS - 2 ER - TY - JOUR A1 - Nickel, Joachim A1 - Mueller, Thomas D. T1 - Specification of BMP signaling JF - Cells N2 - Bone Morphogenetic Proteins (BMPs) together with the Growth and Differentiation Factors (GDFs) form the largest subgroup of the Transforming Growth Factor (TGF)β family and represent secreted growth factors, which play an essential role in many aspects of cell communication in higher organisms. As morphogens they exert crucial functions during embryonal development, but are also involved in tissue homeostasis and regeneration in the adult organism. Their involvement in maintenance and repair processes of various tissues and organs made these growth factors highly interesting targets for novel pharmaceutical applications in regenerative medicine. A hallmark of the TGFβ protein family is that all of the more than 30 growth factors identified to date signal by binding and hetero-oligomerization of a very limited set of transmembrane serine-threonine kinase receptors, which can be classified into two subgroups termed type I and type II. Only seven type I and five type II receptors exist for all 30plus TGFβ members suggesting a pronounced ligand-receptor promiscuity. Indeed, many TGFβ ligands can bind the same type I or type II receptor and a particular receptor of either subtype can usually interact with and bind various TGFβ ligands. The possible consequence of this ligand-receptor promiscuity is further aggravated by the finding that canonical TGFβ signaling of all family members seemingly results in the activation of just two distinct signaling pathways, that is either SMAD2/3 or SMAD1/5/8 activation. While this would implicate that different ligands can assemble seemingly identical receptor complexes that activate just either one of two distinct pathways, in vitro and in vivo analyses show that the different TGFβ members exert quite distinct biological functions with high specificity. This discrepancy indicates that our current view of TGFβ signaling initiation just by hetero-oligomerization of two receptor subtypes and transduction via two main pathways in an on-off switch manner is too simplified. Hence, the signals generated by the various TGFβ members are either quantitatively interpreted using the subtle differences in their receptor-binding properties leading to ligand-specific modulation of the downstream signaling cascade or additional components participating in the signaling activation complex allow diversification of the encoded signal in a ligand-dependent manner at all cellular levels. In this review we focus on signal specification of TGFβ members, particularly of BMPs and GDFs addressing the role of binding affinities, specificities, and kinetics of individual ligand-receptor interactions for the assembly of specific receptor complexes with potentially distinct signaling properties. KW - TGFβ/BMP signaling KW - ligand-receptor promiscuity KW - signal specification Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-193869 SN - 2073-4409 VL - 8 IS - 12 ER - TY - JOUR A1 - Böhm, Jennifer A1 - Scherzer, Sönke A1 - Krol, Elzbieta A1 - Kreuzer, Ines A1 - von Meyer, Katharina A1 - Lorey, Christian A1 - Mueller, Thomas D. A1 - Shabala, Lana A1 - Monte, Isabel A1 - Solano, Roberto A1 - Al-Rasheid, Khaled A. S. A1 - Rennenberg, Heinz A1 - Shabala, Sergey A1 - Neher, Erwin A1 - Hedrich, Rainer T1 - The Venus flytrap Dionaea muscipula counts prey-induced action potentials to induce sodium uptake JF - Current Biology N2 - Carnivorous plants, such as the Venus flytrap (Dionaea muscipula), depend on an animal diet when grown in nutrient-poor soils. When an insect visits the trap and tilts the mechanosensors on the inner surface, action potentials (APs) are fired. After a moving object elicits two APs, the trap snaps shut, encaging the victim. Panicking preys repeatedly touch the trigger hairs over the subsequent hours, leading to a hermetically closed trap, which via the gland-based endocrine system is flooded by a prey-decomposing acidic enzyme cocktail. Here, we asked the question as to how many times trigger hairs have to be stimulated (e.g., now many APs are required) for the flytrap to recognize an encaged object as potential food, thus making it worthwhile activating the glands. By applying a series of trigger-hair stimulations, we found that the touch hormone jasmonic acid (JA) signaling pathway is activated after the second stimulus, while more than three APs are required to trigger an expression of genes encoding prey-degrading hydrolases, and that this expression is proportional to the number of mechanical stimulations. A decomposing animal contains a sodium load, and we have found that these sodium ions enter the capture organ via glands. We identified a flytrap sodium channel DmHKT1 as responsible for this sodium acquisition, with the number of transcripts expressed being dependent on the number of mechano-electric stimulations. Hence, the number of APs a victim triggers while trying to break out of the trap identifies the moving prey as a struggling Na\(^+\)-rich animal and nutrition for the plant. KW - jasmonic acid biosynthesis KW - gene expression KW - signal transduction KW - transporters KW - Arabidopsis Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-190870 VL - 26 IS - 3 ER - TY - JOUR A1 - Siverino, Claudia A1 - Fahmy-Garcia, Shorouk A1 - Mumcuoglu, Didem A1 - Oberwinkler, Heike A1 - Muehlemann, Markus A1 - Mueller, Thomas A1 - Farrell, Eric A1 - van Osch, Gerjo J. V. M. A1 - Nickel, Joachim T1 - Site-directed immobilization of an engineered bone morphogenetic protein 2 (BMP2) variant to collagen-based microspheres induces bone formation in vivo JF - International Journal of Molecular Sciences N2 - For the treatment of large bone defects, the commonly used technique of autologous bone grafting presents several drawbacks and limitations. With the discovery of the bone-inducing capabilities of bone morphogenetic protein 2 (BMP2), several delivery techniques were developed and translated to clinical applications. Implantation of scaffolds containing adsorbed BMP2 showed promising results. However, off-label use of this protein-scaffold combination caused severe complications due to an uncontrolled release of the growth factor, which has to be applied in supraphysiological doses in order to induce bone formation. Here, we propose an alternative strategy that focuses on the covalent immobilization of an engineered BMP2 variant to biocompatible scaffolds. The new BMP2 variant harbors an artificial amino acid with a specific functional group, allowing a site-directed covalent scaffold functionalization. The introduced artificial amino acid does not alter BMP2′s bioactivity in vitro. When applied in vivo, the covalently coupled BMP2 variant induces the formation of bone tissue characterized by a structurally different morphology compared to that induced by the same scaffold containing ab-/adsorbed wild-type BMP2. Our results clearly show that this innovative technique comprises translational potential for the development of novel osteoinductive materials, improving safety for patients and reducing costs. KW - bone morphogenetic protein 2 (BMP2) KW - bone regeneration KW - covalent coupling KW - subcutaneous animal model Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-284572 SN - 1422-0067 VL - 23 IS - 7 ER - TY - JOUR A1 - Müller, Thomas A1 - Mueller, Bernhard Klaus A1 - Riederer, Peter T1 - Perspective: Treatment for disease modification in chronic neurodegeneration JF - Cells N2 - Symptomatic treatments are available for Parkinson's disease and Alzheimer's disease. An unmet need is cure or disease modification. This review discusses possible reasons for negative clinical study outcomes on disease modification following promising positive findings from experimental research. It scrutinizes current research paradigms for disease modification with antibodies against pathological protein enrichment, such as α-synuclein, amyloid or tau, based on post mortem findings. Instead a more uniform regenerative and reparative therapeutic approach for chronic neurodegenerative disease entities is proposed with stimulation of an endogenously existing repair system, which acts independent of specific disease mechanisms. The repulsive guidance molecule A pathway is involved in the regulation of peripheral and central neuronal restoration. Therapeutic antagonism of repulsive guidance molecule A reverses neurodegeneration according to experimental outcomes in numerous disease models in rodents and monkeys. Antibodies against repulsive guidance molecule A exist. First clinical studies in neurological conditions with an acute onset are under way. Future clinical trials with these antibodies should initially focus on well characterized uniform cohorts of patients. The efficiency of repulsive guidance molecule A antagonism and associated stimulation of neurogenesis should be demonstrated with objective assessment tools to counteract dilution of therapeutic effects by subjectivity and heterogeneity of chronic disease entities. Such a research concept will hopefully enhance clinical test strategies and improve the future therapeutic armamentarium for chronic neurodegeneration. KW - neurodegeneration KW - repulsive guidance molecule A KW - neuroprotection KW - repair KW - oxidative stress KW - apoptosis KW - neurogenesis Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-236644 SN - 2073-4409 VL - 10 IS - 4 ER - TY - JOUR A1 - Jodeleit, Henrika A1 - Palamides, Pia A1 - Beigel, Florian A1 - Mueller, Thomas A1 - Wolf, Eckhard A1 - Siebeck, Matthias A1 - Gropp, Roswitha T1 - Design and validation of a disease network of inflammatory processes in the NSG-UC mouse model JF - Journal of Translational Medicine N2 - Background: Ulcerative colitis (UC) is a highly progressive inflammatory disease that requires the interaction of epithelial, immune, endothelial and muscle cells and fibroblasts. Previous studies suggested two inflammatory conditions in UC-patients: ‘acute’ and ‘remodeling’ and that the design of a disease network might improve the understanding of the inflammatory processes. The objective of the study was to design and validate a disease network in the NOD-SCID IL2rγ\(^{null}\) (NSG)-UC mouse model to get a better understanding of the inflammatory processes. Methods: Leukocytes were isolated from the spleen of NSG-UC mice and subjected to flow cytometric analysis. RT-PCR and RNAseq analysis were performed from distal parts of the colon. Based on these analyses and the effects of interleukins, chemokines and growth factors described in the literature, a disease network was designed. To validate the disease network the effect of infliximab and pitrakinra was tested in the NSG-UC model. A clinical- and histological score, frequencies of human leukocytes isolated from spleen and mRNA expression levels from distal parts of the colon were determined. Results: Analysis of leukocytes isolated from the spleen of challenged NSG-UC mice corroborated CD64, CD163 and CD1a expressing CD14+ monocytes, CD1a expressing CD11b+ macrophages and HGF, TARC, IFNγ and TGFß1 mRNA as inflammatory markers. The disease network suggested that a proinflammatory condition elicited by IL-17c and lipids and relayed by cytotoxic T-cells, Th17 cells and CD1a expressing macrophages and monocytes. Conversely, the remodeling condition was evoked by IL-34 and TARC and promoted by Th2 cells and M2 monocytes. Mice benefitted from treatment with infliximab as indicated by the histological- and clinical score. As predicted by the disease network infliximab reduced the proinflammatory response by suppressing M1 monocytes and CD1a expressing monocytes and macrophages and decreased levels of IFNγ, TARC and HGF mRNA. As predicted by the disease network inflammation aggravated in the presence of pitrakinra as indicated by the clinical and histological score, elevated frequencies of CD1a expressing macrophages and TNFα and IFNγ mRNA levels. Conclusions: The combination of the disease network and the NSG-UC animal model might be developed into a powerful tool to predict efficacy or in-efficacy and potential mechanistic side effects. KW - Autoimmunity KW - Disease network KW - Inflammatory bowel disease KW - NSG KW - NSG-UC KW - Ulcerative colitis Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225516 VL - 15 ER - TY - JOUR A1 - Schatton, Tobias A1 - Yang, Jun A1 - Kleffel, Sonja A1 - Uehara, Mayuko A1 - Barthel, Steven R. A1 - Schlapbach, Christoph A1 - Zhan, Qian A1 - Dudeney, Stephen A1 - Mueller, Hansgeorg A1 - Lee, Nayoung A1 - de Vries, Juliane C. A1 - Meier, Barbara A1 - Beken, Seppe Vander A1 - Kluth, Mark A. A1 - Ganss, Christoph A1 - Sharpe, Arlene H. A1 - Waaga-Gasser, Ana Maria A1 - Sayegh, Mohamed H. A1 - Abdi, Reza A1 - Scharffetter-Kochanek, Karin A1 - Murphy, George F. A1 - Kupper, Thomas S. A1 - Frank, Natasha Y. A1 - Frank, Markus H. T1 - ABCB5 Identifies Immunoregulatory Dermal Cells JF - Cell Reports N2 - Cell-based strategies represent a new frontier in the treatment of immune-mediated disorders. However, the paucity of markers for isolation of molecularly defined immunomodulatory cell populations poses a barrier to this field. Here, we show that ATP-binding cassette member B5 (ABCB5) identifies dermal immunoregulatory cells (DIRCs) capable of exerting therapeutic immunoregulatory functions through engagement of programmed cell death 1 (PD-1). Purified Abcb5\(^+\) DIRCs suppressed T cell proliferation, evaded immune rejection, homed to recipient immune tissues, and induced Tregs in vivo. In fully major-histocompatibility-complex-mismatched cardiac allotransplantation models, allogeneic DIRCs significantly prolonged allograft survival. Blockade of DIRC-expressed PD-1 reversed the inhibitory effects of DIRCs on T cell activation, inhibited DIRC-dependent Treg induction, and attenuated DIRC-induced prolongation of cardiac allograft survival, indicating that DIRC immunoregulatory function is mediated, at least in part, through PD-1. Our results identify ABCB5\(^+\) DIRCs as a distinct immunoregulatory cell population and suggest promising roles of this expandable cell subset in cellular immunotherapy. KW - mesenchymal stem cells KW - P-glycoprotein KW - regulatory T cells KW - maintain immune homeostasis KW - malignant melanoma KW - in vivo KW - skin KW - generation KW - transplant KW - tolerance Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-149989 VL - 12 SP - 1564 EP - 1574 ER - TY - JOUR A1 - Stange, Katja A1 - Désir, Julie A1 - Kakar, Naseebullah A1 - Mueller, Thomas D. A1 - Budde, Birgit S. A1 - Gordon, Christopher T. A1 - Horn, Denise A1 - Seemann, Petra A1 - Borck, Guntram T1 - A hypomorphic BMPR1B mutation causes du Pan acromesomelic dysplasia JF - Orphanet Journal of Rare Diseases N2 - Background: Grebe dysplasia, Hunter-Thompson dysplasia, and du Pan dysplasia constitute a spectrum of skeletal dysplasias inherited as an autosomal recessive trait characterized by short stature, severe acromesomelic shortening of the limbs, and normal axial skeleton. The majority of patients with these disorders have biallelic loss-of-function mutations of GDF5. In single instances, Grebe dysplasia and a Grebe dysplasia-like phenotype with genital anomalies have been shown to be caused by mutations in BMPR1B, encoding a GDF5 receptor. Methods: We clinically and radiologically characterised an acromesomelic chondrodysplasia in an adult woman born to consanguineous parents. We sequenced GDF5 and BMPR1B on DNA of the proposita. We performed 3D structural analysis and luciferase reporter assays to functionally investigate the identified BMPR1B mutation. Results: We extend the genotype-phenotype correlation in the acromesomelic chondrodysplasias by showing that the milder du Pan dysplasia can be caused by a hypomorphic BMPR1B mutation. We show that the homozygous c.91C>T, p.(Arg31Cys) mutation causing du Pan dysplasia leads to a significant loss of BMPR1B function, but to a lesser extent than the previously reported p.Cys53Arg mutation that results in the more severe Grebe dysplasia. Conclusions: The phenotypic severity gradient of the clinically and radiologically related acromesomelic chondrodysplasia spectrum of skeletal disorders may be due to the extent of functional impairment of the ligand-receptor pair GDF5-BMPR1B. KW - linkage analysis KW - chondrodysplasia KW - specificity KW - Grebe dysplasia KW - BMPR1B KW - du Pan dysplasia KW - tool KW - missense KW - grebe KW - protein-1 CDMP1 gene KW - Acromesomelic dysplasias Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-151650 VL - 10 IS - 84 ER - TY - JOUR A1 - Hedrich, Rainer A1 - Mueller, Thomas D. A1 - Becker, Dirk A1 - Marten, Irene T1 - Structure and Function of TPC1 Vacuole SV Channel Gains Shape JF - Molecular Plant N2 - Plants and animals in endosomes operate TPC1/SV-type cation channels. All plants harbor at least one TPC1 gene. Although the encoded SV channel was firstly discovered in the plant vacuole membrane two decades ago, its biological function has remained enigmatic. Recently, the structure of a plant TPC1/SV channel protein was determined. Insights into the 3D topology has now guided site-directed mutation approaches, enabling structure–function analyses of TPC1/SV channels to shed new light on earlier findings. Fou2 plants carrying a hyperactive mutant form of TPC1 develop wounding stress phenotypes. Recent studies with fou2 and mutants that lack functional TPC1 have revealed atypical features in local and long-distance stress signaling, providing new access to the previously mysterious biology of this vacuolar cation channel type in planta. KW - Ca2+ sensors KW - TPC1/SV channel KW - vacuole membrane voltage KW - voltage sensor Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228046 VL - 11 ER - TY - JOUR A1 - Lehmann, Julian A1 - Jørgensen, Morten E. A1 - Fratz, Stefanie A1 - Müller, Heike M. A1 - Kusch, Jana A1 - Scherzer, Sönke A1 - Navarro-Retamal, Carlos A1 - Mayer, Dominik A1 - Böhm, Jennifer A1 - Konrad, Kai R. A1 - Terpitz, Ulrich A1 - Dreyer, Ingo A1 - Mueller, Thomas D. A1 - Sauer, Markus A1 - Hedrich, Rainer A1 - Geiger, Dietmar A1 - Maierhofer, Tobias T1 - Acidosis-induced activation of anion channel SLAH3 in the flooding-related stress response of Arabidopsis JF - Current Biology N2 - Plants, as sessile organisms, gained the ability to sense and respond to biotic and abiotic stressors to survive severe changes in their environments. The change in our climate comes with extreme dry periods but also episodes of flooding. The latter stress condition causes anaerobiosis-triggered cytosolic acidosis and impairs plant function. The molecular mechanism that enables plant cells to sense acidity and convey this signal via membrane depolarization was previously unknown. Here, we show that acidosis-induced anion efflux from Arabidopsis (Arabidopsis thaliana) roots is dependent on the S-type anion channel AtSLAH3. Heterologous expression of SLAH3 in Xenopus oocytes revealed that the anion channel is directly activated by a small, physiological drop in cytosolic pH. Acidosis-triggered activation of SLAH3 is mediated by protonation of histidine 330 and 454. Super-resolution microscopy analysis showed that the increase in cellular proton concentration switches SLAH3 from an electrically silent channel dimer into its active monomeric form. Our results show that, upon acidification, protons directly switch SLAH3 to its open configuration, bypassing kinase-dependent activation. Moreover, under flooding conditions, the stress response of Arabidopsis wild-type (WT) plants was significantly higher compared to SLAH3 loss-of-function mutants. Our genetic evidence of SLAH3 pH sensor function may guide the development of crop varieties with improved stress tolerance. KW - SLAH3 KW - S-type anion channel KW - hypoxia KW - pH KW - cytosolic acidification KW - flooding KW - PALM KW - stoichiometry Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-363320 VL - 31 ER -