TY - THES A1 - Herrmann, Thomas T1 - Sequenz-spezifische Interaktion des murinen präreplikativen Komplexes mit Origin-DNA T1 - Sequence specific interaction of the murine prereplicative Complex with origin DNA N2 - Mit Hilfe von in vivo ChIP-Experimenten identifizierten wir eine präRC Bindungsstelle von -2519 bis -2152 (Fragment B) innerhalb eines „origin of bidirectional replication (OBR)“ der 44 kb langen Maus-rDNA-Einheit. Diese Bindungsstelle befindet sich ungefähr 2,3 kb ubstream des Transkriptionsstartpunktes der RNA-Poymerase I. An dieser Bindungsstelle konnte in der G1-Phase der komplette ORC-Komplex sowie Geminin, MCM3 und -6 nachgewiesen werden. Für den G1/S-Phasenübergang deuten die Ergebnisse darauf hin, dass sich ORC6 und Geminin von Fragment B ablösen, während sich CDC6 und -45 an den ORC-Komplex anlagern. Mit Erreichen der S-Phase konnte gezeigt werden, dass sich CDC6 und -45 sowie ORC1 wieder ablösen und ein Core-Komplex von ORC2-5 sowie MCM3 und -6 gebunden bleibt. Außerdem konnte an Fragment B eine spezifische Bindung eines aus FM3A-Zellkernprotein angereicherten präRC-Komplexes (Komplex A) auch in vitro mit Hilfe von EMSA-Experimenten beobachtet werden. Die Bindungsaktivität von Komplex A an Fragment B konnte durch ATP verstärkt werden. N2 - Using chromatin immunoprecipitation assays (ChIP) we identified in vivo a preRC binding site located from -2519 to –2152 (fragment B) within a previously mapped origin of bidirectional replication of the murine rDNA locus located approximately 2.3 kb upstream of the transcription start site of RNA polymerase I. At this sequence, ORC1, -2, -3, -4, -5 -6 as well as Geminin, MCM3 and -6 are bound in G1 phase; at the G1/S transition also CDC6, and -45 interact whereas ORC6 as well as Geminin dissociates. In S phase, ORC1, CDC6 and -45 are released from the preRC. We have reproduced an ATP-dependent assembly of the preRC at origin DNA in vitro using EMSA-Experiments with partially purified proteins from murine nuclear extracts. KW - Maus KW - Zellzyklus KW - Replikation KW - Replikationsursprung KW - präRC KW - Zellzyklus KW - ATP-Abhängigkeit KW - Maus KW - Origin of Recognition KW - preRC KW - Cell cycle KW - ATP-dependent KW - murine KW - Origin of Recognition Y1 - 2004 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-11241 ER - TY - JOUR A1 - Brandl, Carolin A1 - Ortler, Sonja A1 - Herrmann, Thomas A1 - Cardell, Susanna A1 - Lutz, Manfred B. A1 - Wiendl, Heinz T1 - B7-H1-Deficiency Enhances the Potential of Tolerogenic Dendritic Cells by Activating CD1d-Restricted Type II NKT Cells N2 - Background: Dendritic cells (DC) can act tolerogenic at a semi-mature stage by induction of protective CD4+ T cell and NKT cell responses. Methodology/Principal Findings: Here we studied the role of the co-inhibitory molecule B7-H1 (PD-L1, CD274) on semimature DC that were generated from bone marrow (BM) cells of B7-H12/2 mice and applied to the model of Experimental Autoimmune Encephalomyelitis (EAE). Injections of B7-H1-deficient DC showed increased EAE protection as compared to wild type (WT)-DC. Injections of B7-H12/2 TNF-DC induced higher release of peptide-specific IL-10 and IL-13 after restimulation in vitro together with elevated serum cytokines IL-4 and IL-13 produced by NKT cells, and reduced IL-17 and IFN-c production in the CNS. Experiments in CD1d2/2 and Ja2812/2 mice as well as with type I and II NKT cell lines indicated that only type II NKT cells but not type I NKT cells (invariant NKT cells) could be stimulated by an endogenous CD1d-ligand on DC and were responsible for the increased serum cytokine production in the absence of B7-H1. Conclusions/Significance: Together, our data indicate that BM-DC express an endogenous CD1d ligand and B7-H1 to ihibit type II but not type I NKT cells. In the absence of B7-H1 on these DC their tolerogenic potential to stimulate tolerogenic CD4+ and NKT cell responses is enhanced. KW - Dendritische Zelle Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-68457 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 - Kleinschnitz, Christoph A1 - Grund, Henrike A1 - Wingler, Kirstin A1 - Armitage, Melanie E. A1 - Jones, Emma A1 - Mittal, Manish A1 - Barit, David A1 - Schwarz, Tobias A1 - Geis, Christian A1 - Kraft, Peter A1 - Barthel, Konstanze A1 - Schuhmann, Michael K. A1 - Herrmann, Alexander M. A1 - Meuth, Sven G. A1 - Stoll, Guido A1 - Meurer, Sabine A1 - Schrewe, Anja A1 - Becker, Lore A1 - Gailus-Durner, Valerie A1 - Fuchs, Helmut A1 - Klopstock, Thomas A1 - de Angelis, Martin Hrabe A1 - Jandeleit-Dahm, Karin A1 - Shah, Ajay M. A1 - Weissmann, Norbert A1 - Schmidt, Harald H. H. W. T1 - Post-Stroke Inhibition of Induced NADPH Oxidase Type 4 Prevents Oxidative Stress and Neurodegeneration N2 - Ischemic stroke is the second leading cause of death worldwide. Only one moderately effective therapy exists, albeit with contraindications that exclude 90% of the patients. This medical need contrasts with a high failure rate of more than 1,000 pre-clinical drug candidates for stroke therapies. Thus, there is a need for translatable mechanisms of neuroprotection and more rigid thresholds of relevance in pre-clinical stroke models. One such candidate mechanism is oxidative stress. However, antioxidant approaches have failed in clinical trials, and the significant sources of oxidative stress in stroke are unknown. We here identify NADPH oxidase type 4 (NOX4) as a major source of oxidative stress and an effective therapeutic target in acute stroke. Upon ischemia, NOX4 was induced in human and mouse brain. Mice deficient in NOX4 (Nox42/2) of either sex, but not those deficient for NOX1 or NOX2, were largely protected from oxidative stress, blood-brain-barrier leakage, and neuronal apoptosis, after both transient and permanent cerebral ischemia. This effect was independent of age, as elderly mice were equally protected. Restoration of oxidative stress reversed the stroke-protective phenotype in Nox42/2 mice. Application of the only validated low-molecular-weight pharmacological NADPH oxidase inhibitor, VAS2870, several hours after ischemia was as protective as deleting NOX4. The extent of neuroprotection was exceptional, resulting in significantly improved long-term neurological functions and reduced mortality. NOX4 therefore represents a major source of oxidative stress and novel class of drug target for stroke therapy. KW - Schlaganfall Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-68416 ER - TY - JOUR A1 - Bittner, Stefan A1 - Bobak, Nicole A1 - Feuchtenberger, Martin A1 - Herrmann, Alexander M A1 - Göbel, Kerstin A1 - Kinne, Raimund W A1 - Hansen, Anker J A1 - Budde, Thomas A1 - Kleinschnitz, Christoph A1 - Frey, Oliver A1 - Tony, Hans-Peter A1 - Wiendl, Heinz A1 - Meuth, Sven G T1 - Expression of K\(_2\)\(_P\)5.1 potassium channels on CD4\(^+\)T lymphocytes correlates with disease activity in rheumatoid arthritis patients JF - Arthritis Research & Therapy N2 - Introduction CD4+ T cells express K2P5.1 (TWIK-related acid-sensitive potassium channel 2 (TASK2); KCNK5), a member of the two-pore domain potassium channel family, which has been shown to influence T cell effector functions. Recently, it was shown that K2P5.1 is upregulated upon (autoimmune) T cell stimulation. The aim of this study was to correlate expression levels of K2P5.1 on T cells from patients with rheumatoid arthritis (RA) to disease activity in these patients. Methods Expression levels of K2P5.1 were measured by RT-PCR in the peripheral blood of 58 patients with RA and correlated with disease activity parameters (C-reactive protein levels, erythrocyte sedimentation rates, disease activity score (DAS28) scores). Twenty patients undergoing therapy change were followed-up for six months. Additionally, synovial fluid and synovial biopsies were investigated for T lymphocytes expressing K2P5.1. Results K2P5.1 expression levels in CD4+ T cells show a strong correlation to DAS28 scores in RA patients. Similar correlations were found for serological inflammatory parameters (erythrocyte sedimentation rate, C-reactive protein). In addition, K2P5.1 expression levels of synovial fluid-derived T cells are higher compared to peripheral blood T cells. Prospective data in individual patients show a parallel behaviour of K2P5.1 expression to disease activity parameters during a longitudinal follow-up for six months. Conclusions Disease activity in RA patients correlates strongly with K2P5.1 expression levels in CD4+ T lymphocytes in the peripheral blood in cross-sectional as well as in longitudinal observations. Further studies are needed to investigate the exact pathophysiological mechanisms and to evaluate the possible use of K2P5.1 as a potential biomarker for disease activity and differential diagnosis. KW - neurology Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-139334 VL - 13 IS - R21 ER - TY - JOUR A1 - Biehl, Stefanie C. A1 - Dresler, Thomas A1 - Reif, Andreas A1 - Scheuerpflug, Peter A1 - Deckert, Jürgen A1 - Herrmann, Martin J. T1 - Dopamine Transporter (DAT1) and Dopamine Receptor D4 (DRD4) Genotypes Differentially Impact on Electrophysiological Correlates of Error Processing JF - PLoS One N2 - Recent studies as well as theoretical models of error processing assign fundamental importance to the brain's dopaminergic system. Research about how the electrophysiological correlates of error processing—the error-related negativity (ERN) and the error positivity (Pe)—are influenced by variations of common dopaminergic genes, however, is still relatively scarce. In the present study, we therefore investigated whether polymorphisms in the DAT1 gene and in the DRD4 gene, respectively, lead to interindividual differences in these error processing correlates. One hundred sixty participants completed a version of the Eriksen Flanker Task while a 26-channel EEG was recorded. The task was slightly modified in order to increase error rates. During data analysis, participants were split into two groups depending on their DAT1 and their DRD4 genotypes, respectively. ERN and Pe amplitudes after correct responses and after errors as well as difference amplitudes between errors and correct responses were analyzed. We found a differential effect of DAT1 genotype on the Pe difference amplitude but not on the ERN difference amplitude, while the reverse was true for DRD4 genotype. These findings are in line with predictions from theoretical models of dopaminergic transmission in the brain. They furthermore tie results from clinical investigations of disorders impacting on the dopamine system to genetic variations known to be at-risk genotypes. KW - haplotypes KW - electroencephalography KW - basal ganglia KW - reaction time KW - dopaminergics KW - dopamine KW - ADHD KW - research errors Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-137930 VL - 6 IS - 12 ER - TY - JOUR A1 - Beyersdorf, Niklas A1 - Werner, Sandra A1 - Wolf, Nelli A1 - Herrmann, Thomas A1 - Kerkau, Thomas T1 - Characterization of a New Mouse Model for Peripheral T Cell Lymphoma in Humans JF - PLoS One N2 - Peripheral T cell lymphomas (PTCLs) are associated with a poor prognosis due to often advanced disease at the time of diagnosis and due to a lack of efficient therapeutic options. Therefore, appropriate animal models of PTCL are vital to improve clinical management of this disease. Here, we describe a monoclonal CD8\(^+\) CD4\(^−\) αβ T cell receptor Vβ2\(^+\) CD28\(^+\) T cell lymphoma line, termed T8-28. T8-28 cells were isolated from an un-manipulated adult BALB/c mouse housed under standard pathogen-free conditions. T8-28 cells induced terminal malignancy upon adoptive transfer into syngeneic BALB/c mice. Despite intracellular expression of the cytotoxic T cell differentiation marker granzyme B, T8-28 cells appeared to be defective with respect to cytotoxic activity as read-out in vitro. Among the protocols tested, only addition of interleukin 2 in vitro could partially compensate for the in vivo micro-milieu in promoting growth of the T8-28 lymphoma cells. KW - T cells KW - cytotoxic T cells KW - mouse models KW - interleukins KW - cell staining KW - lymphomas KW - fluorescence-activated cell sorting KW - lymph nodes Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-137946 VL - 6 IS - 12 ER - TY - JOUR A1 - Barth, Thomas F. E. A1 - Herrmann, Tobias S. A1 - Tappe, Dennis A1 - Stark, Lorenz A1 - Grüner, Beate A1 - Buttenschoen, Klaus A1 - Hillenbrand, Andreas A1 - Juchems, Markus A1 - Henne-Bruns, Doris A1 - Kern, Petra A1 - Seitz, Hanns M. A1 - Möller, Peter A1 - Rausch, Robert L. A1 - Kern, Peter A1 - Deplazes, Peter T1 - Sensitive and Specific Immunohistochemical Diagnosis of Human Alveolar Echinococcosis with the Monoclonal Antibody Em2G11 JF - PLoS Neglected Tropical Diseases N2 - Background: Alveolar echinococcosis (AE) is caused by the metacestode stage of Echinococcus multilocularis. Differential diagnosis with cystic echinococcosis (CE) caused by E. granulosus and AE is challenging. We aimed at improving diagnosis of AE on paraffin sections of infected human tissue by immunohistochemical testing of a specific antibody. Methodology/Principal Findings: We have analysed 96 paraffin archived specimens, including 6 cutting needle biopsies and 3 fine needle aspirates, from patients with suspected AE or CE with the monoclonal antibody (mAb) Em2G11 specific for the Em2 antigen of E. multilocularis metacestodes. In human tissue, staining with mAb Em2G11 is highly specific for E. multilocularis metacestodes while no staining is detected in CE lesions. In addition, the antibody detects small particles of E. multilocularis (spems) of less than 1 mm outside the main lesion in necrotic tissue, liver sinusoids and lymphatic tissue most probably caused by shedding of parasitic material. The conventional histological diagnosis based on haematoxylin and eosin and PAS stainings were in accordance with the immunohistological diagnosis using mAb Em2G11 in 90 of 96 samples. In 6 samples conventional subtype diagnosis of echinococcosis had to be adjusted when revised by immunohistology with mAb Em2G11. Conclusions/Significance: Immunohistochemistry with the mAb Em2G11 is a new, highly specific and sensitive diagnostic tool for AE. The staining of small particles of E. multilocularis (spems) outside the main lesion including immunocompetent tissue, such as lymph nodes, suggests a systemic effect on the host. KW - cells KW - multilocularis KW - antigen Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-135371 VL - 6 IS - 10 ER - TY - JOUR A1 - Verner, Martin A1 - Herrmann, Martin J. A1 - Troche, Stefan J. A1 - Roebers, Claudia M. A1 - Rammsayer, Thomas H. T1 - Cortical oxygen consumption in mental arithmetic as a function of task difficulty: a near-infrared spectroscopy approach JF - Frontiers in Human Neuroscience N2 - The present study investigated changes in cortical oxygenation during mental arithmetic using near-infrared spectroscopy (NIRS). Twenty-nine male volunteers were examined using a 52-channel continuous wave system for analyzing activity in prefrontal areas. With the help of a probabilistic mapping method, three regions of interest (ROIs) on each hemisphere were defined: The inferior frontal gyri (IFG), the middle frontal gyri (MFG), and the superior frontal gyri (SFG). Oxygenation as an indicator of functional brain activation was compared over the three ROI and two levels of arithmetic task difficulty (simple and complex additions). In contrast to most previous studies using fMRI or NIRS, in the present study arithmetic tasks were presented verbally in analogue to many daily life situations. With respect to task difficulty, more complex addition tasks led to higher oxygenation in all defined ROI except in the left IFG compared to simple addition tasks. When compared to the channel positions covering different gyri of the temporal lobe, the observed sensitivity to task complexity was found to be restricted to the specified ROIs. As to the comparison of ROIs, the highest oxygenation was found in the IFG, while MFG and SFG showed significantly less activation compared to IFG. The present cognitive-neuroscience approach demonstrated that NIRS is a suitable and highly feasible research tool for investigating and quantifying neural effects of increasing arithmetic task difficulty. KW - cortical activation KW - working memory KW - individual differences KW - prefrontal cortex KW - FMRI KW - brain-regions KW - subsctraction KW - activation KW - bold KW - intelligibility KW - NIRS KW - oxygen consumption KW - task difficulty KW - mental arithmetic KW - near-infrared spectroscopy Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-122449 SN - 1662-5161 VL - 7 IS - 217 ER - TY - JOUR A1 - Kopf, Juliane A1 - Dresler, Thomas A1 - Reicherts, Philipp A1 - Herrmann, Martin J. A1 - Reif, Andreas T1 - The Effect of Emotional Content on Brain Activation and the Late Positive Potential in a Word n-back Task JF - PLoS ONE N2 - Introduction There is mounting evidence for the influence of emotional content on working memory performance. This is particularly important in light of the emotion processing that needs to take place when emotional content interferes with executive functions. In this study, we used emotional words of different valence but with similar arousal levels in an n-back task. Methods We examined the effects on activation in the prefrontal cortex by means of functional near-infrared spectroscopy (fNIRS) and on the late positive potential (LPP). FNIRS and LPP data were examined in 30 healthy subjects. Results Behavioral results show an influence of valence on the error rate depending on the difficulty of the task: more errors were made when the valence was negative and the task difficult. Brain activation was dependent both on the difficulty of the task and on the valence: negative valence of a word diminished the increase in activation, whereas positive valence did not influence the increase in activation, while difficulty levels increased. The LPP also differentiated between the different valences, and in addition was influenced by the task difficulty, the more difficult the task, the less differentiation could be observed. Conclusions Summarized, this study shows the influence of valence on a verbal working memory task. When a word contained a negative valence, the emotional content seemed to take precedence in contrast to words containing a positive valence. Working memory and emotion processing sites seemed to overlap and compete for resources even when words are carriers of the emotional content. KW - analysis of variance KW - electrode recording KW - electroencephalography KW - emotions KW - eyes KW - near-infrared spectroscopy KW - reaction time KW - working memory Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-96687 ER -