TY - THES A1 - Paunescu, Karina T1 - DNA-Stabilität und Thioredoxin/Thioredoxin Reduktase im Zellkern T1 - DNA-Stability and thioredoxin/thioredoxin reductase in nucleus N2 - Das System Thioredoxin /Thioredoxin Reduktase(Trx/TrxR) ist ein sehr versatiles System zur neutralisation reaktiver Sauerstoffspezies, zur Regulation redox-sensitiver Vorgänge und zur Aktivierung von Transkriptionsfaktoren wie Steroidhormonrezeptoren, AP-1 und NFkB. Das Enzym Thioredoxin Reduktase war zunächst nur als zytosolisches Enzym beschrieben, es ist mittlerweile bekannt, dass es z. B. nach Phorbolester-Stimulation auch sezeniert werden kann. Adäquate Stimuli für die nucläere Translokation von Trx sind z. B. UV-Licht und TNF-Signalling. Zudem wurde in der vorhandenen Arbeit anhand transienter Transfektion und immunhistochemischer Untersuchungen nachgewiesen, dass beide Komponenten des Systems auch im Zellkern präsent sind. Ein Teil er Arbeit stellt die Charakteriesierung der subzellulären Lokalisation zweier Isoformen von Thioredoxin Reduktase 1 mit unterschiedlichem N-Terminus dar. Es konnte gezeigt werden, dass die beiden Isoformen als mRNA und Protein vorhanden sind. Es wurde dann die Interaktion des Enzyms Thioredoxin Reduktase mit anderen Komponenten des Zellkerns, hier speziell mit Enzymen der DNA-Prozessierung untersucht. Zudem wurde in einem Immunpräzipitationsansatz ("Pull-Down-Assay") nucläere Interaktionspartner des Enzyms charakterisiert. Diese Partner sollen nach Gelelektrophorese und MALDI-TOF-Analyse identifiziert werden. Zu den DNA-Prozessierungsenzyme zählt auch Topisomerase I. Durch Antikörpervermittelte Assays gelang es nachzuweisen, dass Topoisomerase I mit TrxR eine Protein-Protein-Wechsekwirkung eingeht. In einem Rekonstruktionssystem mit rekombinanter Topoisomerase I und gerenigter TrxR ergab sich jedoch keiner Hinweis für eine funktionelle Interaktion in DNA-Relaxations-Assay. Die Aufschlüsselung der Protein-Protein-Interaktion, der detaillierten molekularen Mechanismen und ihrer physiologischen relevanz bleibt weiteren Unterschungen vorbehalten. N2 - The mammalian thioredoxin system consists of thioredoxin (Trx), thioredoxin reductase (TrxR), and NADPH. Human Trx was originally cloned as a soluble factor named adult T-cell leukemia-derived factor, which was purified from the conditioned medium of human T-cell lymphotrophic virus-I-transformed CD4+ T-cell line, ATL-2 (Yodoi, J., et al.1992, Nakamura, et al. 1992, 1997, Tagaya, Y., et al. 1989). It participates in many different types of reactions including synthesis of deoxyribonucleotides , redox control of transcription factors, reduction of peroxides, and regulation of apoptosis. The thioredoxin reductases (TrxRs) belong to the flavoprotein family of pyridine nucleotide-disulphide oxidoreductases that includes lipoamide dehydrogenase, glutathione reductase and mercuric ion reductase. Members of this family are homodimeric proteins. Each monomer includes an FAD prosthetic group, an NADPH binding site and an active site containing a redox-active disulphide. Recently it has been reported that the human TrxR1 gene exhibits possible alternative splicing around its first exon (Rundlof AK, et al. 2001). The Arner group reported three isoforms of TrxR mRNA (I, II, V) and Tonissen group identified two further isoforms (isoforms IV and VI) and proposed another (isoform III), that would align with the mouse isoform III.In this work it could be demonstrated, that PCR using isoform specific oligonucleotide primers yielded products for both ATGs, indicating the existence of both mRNA species. Transient transfection of GFP fusion proteins (Trx-N1-EGFP, TrxR-N1-EGFP, TrxR-pDsRed2N1) into osteoblast cells (hFOB) revealed cytosolic localisation of both isoforms. While the isoform ATG1 was also nuclear, ATG2 was very rarely found in the nucleus. Transfection of the ATG1 to ATG2 fragment alone showed cytosolic and nuclear localisation accordingly. Staining of HFOBs and mesenchymal stem cells with Trx antibody revealed that Trx was preferentially localised in the nucleus; using an antibody to TrxR it was shown that the enzyme was always colocalized with Trx in mesenchymal stem cells, osteoblast-like cells and chondrocyte like cells. In summary we could characterise the subcellular localisation of the Trx/TrxR system in osteoblasts and mesenchymal stem cells with respect to the expression of TrxR isoforms. The role of the ribonucleotide reductase TrxR in the nucleus remains to be elucidated. Besides its well characterized function in modulation of transcription factor DNA binding, the role in nuclear antioxidative defense and/or DNA processing and repair might be hypothesized. KW - Genom KW - Thioredoxin KW - Thioredoxin Reduktase KW - Topoisomerase I KW - Tumorinstabilität KW - genom KW - Thioredoxin KW - Thioredoxin reductase KW - Topoisomerase I KW - Tumorinstability Y1 - 2003 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-6999 ER - TY - JOUR A1 - Berenike Herrmann, J. A1 - van Dalen-Oskam, Karina A1 - Schöch, Christof T1 - Revisiting Style, a Key Concept in Literary Studies JF - Journal of Literary Theory N2 - Language and literary studies have studied style for centuries, and even since the advent of ›stylistics‹ as a discipline at the beginning of the twentieth century, definitions of ›style‹ have varied heavily across time, space and fields. Today, with increasingly large collections of literary texts being made available in digital form, computational approaches to literary style are proliferating. New methods from disciplines such as corpus linguistics and computer science are being adopted and adapted in interrelated fields such as computational stylistics and corpus stylistics, and are facilitating new approaches to literary style. The relation between definitions of style in established linguistic or literary stylistics, and definitions of style in computational or corpus stylistics has not, however, been systematically assessed. This contribution aims to respond to the need to redefine style in the light of this new situation and to establish a clearer perception of both the overlap and the boundaries between ›mainstream‹ and ›computational‹ and/or ›empirical‹ literary stylistics. While stylistic studies of non-literary texts are currently flourishing, our contribution deliberately centers on those approaches relevant to ›literary stylistics‹. It concludes by proposing an operational definition of style that we hope can act as a common ground for diverse approaches to literary style, fostering transdisciplinary research. The focus of this contribution is on literary style in linguistics and literary studies (rather than in art history, musicology or fashion), on textual aspects of style (rather than production- or reception-oriented theories of style), and on a descriptive perspective (rather than a prescriptive or didactic one). Even within these limits, however, it appears necessary to build on a broad understanding of the various perspectives on style that have been adopted at different times and in different traditions. For this reason, the contribution first traces the development of the notion of style in three different traditions, those of German, Dutch and French language and literary studies. Despite the numerous links between each other, and between each of them to the British and American traditions, these three traditions each have their proper dynamics, especially with regard to the convergence and/or confrontation between mainstream and computational stylistics. For reasons of space and coherence, the contribution is limited to theoretical developments occurring since 1945. The contribution begins by briefly outlining the range of definitions of style that can be encountered across traditions today: style as revealing a higher-order aesthetic value, as the holistic ›gestalt‹ of single texts, as an expression of the individuality of an author, as an artifact presupposing choice among alternatives, as a deviation from a norm or reference, or as any formal property of a text. The contribution then traces the development of definitions of style in each of the three traditions mentioned, with the aim of giving a concise account of how, in each tradition, definitions of style have evolved over time, with special regard to the way such definitions relate to empirical, quantitative or otherwise computational approaches to style in literary texts. It will become apparent how, in each of the three traditions, foundational texts continue to influence current discussions on literary style, but also how stylistics has continuously reacted to broader developments in cultural and literary theory, and how empirical, quantitative or computational approaches have long ­existed, usually in parallel to or at the margins of mainstream stylistics. The review will also reflect the lines of discussion around style as a property of literary texts – or of any textual entity in general. The perspective on three stylistic traditions is accompanied by a more systematic perspective. The rationale is to work towards a common ground for literary scholars and linguists when talking about (literary) style, across traditions of stylistics, with respect for established definitions of style, but also in light of the digital paradigm. Here, we first show to what extent, at similar or different moments in time, the three traditions have developed comparable positions on style, and which definitions out of the range of possible definitions have been proposed or promoted by which authors in each of the three traditions. On the basis of this synthesis, we then conclude by proposing an operational definition of style that is an attempt to provide a common ground for both mainstream and computational literary stylistics. This definition is discussed in some detail in order to explain not only what is meant by each term in the definition, but also how it relates to computational analyses of style – and how this definition aims to avoid some of the pitfalls that can be perceived in earlier definitions of style. Our definition, we hope, will be put to use by a new generation of computational, quantitative, and empirical studies of style in literary texts. KW - literary studies Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-194349 SN - 1862-8990 SN - 1862-5290 N1 - This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively. VL - 9 IS - 1 ER - TY - JOUR A1 - Vendelova, Emilia A1 - de Lima, Jeferson Camargo A1 - Lorenzatto, Karina Rodrigues A1 - Monteiro, Karina Mariante A1 - Mueller, Thomas A1 - Veepaschit, Jyotishman A1 - Grimm, Clemens A1 - Brehm, Klaus A1 - Hrčková, Gabriela A1 - Lutz, Manfred B. A1 - Ferreira, Henrique B. A1 - Nono, Justin Komguep T1 - Proteomic Analysis of Excretory-Secretory Products of Mesocestoides corti Metacestodes Reveals Potential Suppressors of Dendritic Cell Functions JF - PLoS Neglected Tropical Diseases N2 - Accumulating evidences have assigned a central role to parasite-derived proteins in immunomodulation. Here, we report on the proteomic identification and characterization of immunomodulatory excretory-secretory (ES) products from the metacestode larva (tetrathyridium) of the tapeworm Mesocestoides corti (syn. M. vogae). We demonstrate that ES products but not larval homogenates inhibit the stimuli-driven release of the pro-inflammatory, Th1-inducing cytokine IL-12p70 by murine bone marrow-derived dendritic cells (BMDCs). Within the ES fraction, we biochemically narrowed down the immunosuppressive activity to glycoproteins since active components were lipid-free, but sensitive to heat- and carbohydrate-treatment. Finally, using bioassay-guided chromatographic analyses assisted by comparative proteomics of active and inactive fractions of the ES products, we defined a comprehensive list of candidate proteins released by M. corti tetrathyridia as potential suppressors of DC functions. Our study provides a comprehensive library of somatic and ES products and highlight some candidate parasite factors that might drive the subversion of DC functions to facilitate the persistence of M. corti tetrathyridia in their hosts. KW - proteomic analysis KW - excretory-secretory KW - Mesocestoides corti Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-166742 VL - 10 IS - 10 ER - TY - JOUR A1 - Kirschmer, Nadine A1 - Bandleon, Sandra A1 - von Ehrlich-Treuenstätt, Viktor A1 - Hartmann, Sonja A1 - Schaaf, Alice A1 - Lamprecht, Anna-Karina A1 - Miranda-Laferte, Erick A1 - Langsenlehner, Tanja A1 - Ritter, Oliver A1 - Eder, Petra T1 - TRPC4α and TRPC4β Similarly Affect Neonatal Cardiomyocyte Survival during Chronic GPCR Stimulation JF - PLoS ONE N2 - The Transient Receptor Potential Channel Subunit 4 (TRPC4) has been considered as a crucial Ca\(^{2+}\) component in cardiomyocytes promoting structural and functional remodeling in the course of pathological cardiac hypertrophy. TRPC4 assembles as homo or hetero-tetramer in the plasma membrane, allowing a non-selective Na\(^{+}\) and Ca\(^{2+}\) influx. Gαq protein-coupled receptor (GPCR) stimulation is known to increase TRPC4 channel activity and a TRPC4-mediated Ca\(^{2+}\) influx which has been regarded as ideal Ca\(^{2+}\) source for calcineurin and subsequent nuclear factor of activated T-cells (NFAT) activation. Functional properties of TRPC4 are also based on the expression of the TRPC4 splice variants TRPC4α and TRPC4β. Aim of the present study was to analyze cytosolic Ca\(^{2+}\) signals, signaling, hypertrophy and vitality of cardiomyocytes in dependence on the expression level of either TRPC4α or TRPC4β. The analysis of Ca\(^{2+}\) transients in neonatal rat cardiomyocytes (NRCs) showed that TRPC4α and TRPC4β affected Ca\(^{2+}\) cycling in beating cardiomyocytes with both splice variants inducing an elevation of the Ca\(^{2+}\) transient amplitude at baseline and TRPC4β increasing the Ca\(^{2+}\) peak during angiotensin II (Ang II) stimulation. NRCs infected with TRPC4β (Ad-C4β) also responded with a sustained Ca\(^{2+}\) influx when treated with Ang II under non-pacing conditions. Consistent with the Ca\(^{2+}\) data, NRCs infected with TRPC4α (Ad-C4α) showed an elevated calcineurin/NFAT activity and a baseline hypertrophic phenotype but did not further develop hypertrophy during chronic Ang II/phenylephrine stimulation. Down-regulation of endogenous TRPC4α reversed these effects, resulting in less hypertrophy of NRCs at baseline but a markedly increased hypertrophic enlargement after chronic agonist stimulation. Ad-C4β NRCs did not exhibit baseline calcineurin/NFAT activity or hypertrophy but responded with an increased calcineurin/NFAT activity after GPCR stimulation. However, this effect was not translated into an increased propensity towards hypertrophy but rather less hypertrophy during GPCR stimulation. Further analyses revealed that, although hypertrophy was preserved in Ad-C4α NRCs and even attenuated in Ad-C4β NRCs, cardiomyocytes had an increased apoptosis rate and thus were less viable after chronic GPCR stimulation. These findings suggest that TRPC4α and TRPC4β differentially affect Ca\(^{2+}\) signals, calcineurin/NFAT signaling and hypertrophy but similarly impair cardiomyocyte viability during GPCR stimulation. KW - Apoptosis KW - calcineurin signaling cascade KW - small interfering RNAs KW - G protein coupled receptors KW - hyperexpression techniques KW - heart KW - adenoviruses KW - cardiac pacing Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-178539 VL - 11 IS - 12 ER - TY - JOUR A1 - Babski, Julia A1 - Haas, Karina A. A1 - Näther-Schindler, Daniela A1 - Pfeiffer, Friedhelm A1 - Förstner, Konrad U. A1 - Hammelmann, Matthias A1 - Hilker, Rolf A1 - Becker, Anke A1 - Sharma, Cynthia M. A1 - Marchfelder, Anita A1 - Soppa, Jörg T1 - Genome-wide identification of transcriptional start sites in the haloarchaeon Haloferax volcanii based on differential RNA-Seq (dRNA-Seq) JF - BMC Genomics N2 - Background Differential RNA-Seq (dRNA-Seq) is a recently developed method of performing primary transcriptome analyses that allows for the genome-wide mapping of transcriptional start sites (TSSs) and the identification of novel transcripts. Although the transcriptomes of diverse bacterial species have been characterized by dRNA-Seq, the transcriptome analysis of archaeal species is still rather limited. Therefore, we used dRNA-Seq to characterize the primary transcriptome of the model archaeon Haloferax volcanii. Results Three independent cultures of Hfx. volcanii grown under optimal conditions to the mid-exponential growth phase were used to determine the primary transcriptome and map the 5′-ends of the transcripts. In total, 4749 potential TSSs were detected. A position weight matrix (PWM) was derived for the promoter predictions, and the results showed that 64 % of the TSSs were preceded by stringent or relaxed basal promoters. Of the identified TSSs, 1851 belonged to protein-coding genes. Thus, fewer than half (46 %) of the 4040 protein-coding genes were expressed under optimal growth conditions. Seventy-two percent of all protein-coding transcripts were leaderless, which emphasized that this pathway is the major pathway for translation initiation in haloarchaea. A total of 2898 of the TSSs belonged to potential non-coding RNAs, which accounted for an unexpectedly high fraction (61 %) of all transcripts. Most of the non-coding TSSs had not been previously described (2792) and represented novel sequences (59 % of all TSSs). A large fraction of the potential novel non-coding transcripts were cis-antisense RNAs (1244 aTSSs). A strong negative correlation between the levels of antisense transcripts and cognate sense mRNAs was found, which suggested that the negative regulation of gene expression via antisense RNAs may play an important role in haloarchaea. The other types of novel non-coding transcripts corresponded to internal transcripts overlapping with mRNAs (1153 iTSSs) and intergenic small RNA (sRNA) candidates (395 TSSs). Conclusion This study provides a comprehensive map of the primary transcriptome of Hfx. volcanii grown under optimal conditions. Fewer than half of all protein-coding genes have been transcribed under these conditions. Unexpectedly, more than half of the detected TSSs belonged to several classes of non-coding RNAs. Thus, RNA-based regulation appears to play a more important role in haloarchaea than previously anticipated. KW - Archaea KW - dRNA-Seq KW - Promoter KW - Non-coding RNAs KW - sRNA KW - Haloferax volcanii KW - Transcriptome KW - Leaderless transcript KW - Antisense RNA Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-164553 VL - 17 IS - 629 ER - TY - JOUR A1 - Rudovick, Ladius A1 - Brauner, Jan M. A1 - Englert, Johanna A1 - Seemann, Carolina A1 - Plugaru, Karina A1 - Kidenya, Benson R. A1 - Kalluvya, Samuel E. A1 - Scheller, Carsten A1 - Kasang, Christa T1 - Prevalence of pretreatment HIV drug resistance in Mwanza, Tanzania JF - Journal of Antimicrobial Chemotherapy N2 - Background: In a 2008-10 study, we found a pretreatment HIV drug resistance (PDR) prevalence of 18.2% in patients at Bugando Medical Centre (BMC) in Mwanza, Tanzania. Objectives: To determine the prevalence of PDR and transmitted HIV drug resistance (TDR) in patients visiting the BMC from 2013 to 2015. Methods: Adult outpatients were sequentially enrolled into two groups, separated by whether they were initiating ART. Previous exposure to antiretroviral drugs, except for prevention of mother-to-child transmission, was an exclusion criterion. HIV pol sequences were analysed according to WHO guidelines for surveillance of PDR and TDR. Results: Two hundred and thirty-five sequences were analysed (138 ART initiators, 97 non-initiators). The prevalence of PDR was 4.7% (95% CI 2.6%-8.2%) overall, 3.1% (95% CI 1.1%-8.7%) for non-initiators and 5.8% (95% CI 3.0%-11.0%) for ART initiators. PDR to NNRTIs and nucleoside or nucelotide reverse transcriptase inhibitors was found in 3.0% (95% CI 1.5%-6.0%) and 1.7% (95% CI 0.7%-4.3%) of patients, respectively. Resistance to PIs was not observed. The prevalence of TDR was 6.0% (95% CI 3.6%-9.8%). Conclusions: Prevalence of PDR significantly decreased compared with 2008-10 and was below the WHO-defined threshold for triggering a public health response. National and systematic surveillance is needed to inform Tanzania's public health strategy. KW - HIV KW - adult KW - anti-hiv agents KW - child KW - mothers KW - nucleosides KW - outpatients KW - reverse transcriptase inhibitors KW - tanzania KW - world health organization KW - guidelines KW - public health medicine KW - anti-retroviral agents KW - non-nucleoside reverse transcriptase inhibitors KW - surveillance KW - medical KW - exclusion criteria KW - prevention Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-227124 VL - 73 IS - 12 ER - TY - INPR A1 - Lindner, Joachim O. A1 - Sultangaleeva, Karina A1 - Röhr, Merle I. S. A1 - Mitric, Roland T1 - metaFALCON: A program package for automatic sampling of conical intersection seams using multistate metadynamics T2 - Journal of Chemical Theory and Computation N2 - The multistate metadynamics for automatic exploration of conical intersection seams and systematic location of minimum energy crossing points in molecular systems and its implementation into the software package metaFALCON is presented. Based on a locally modified energy gap between two Born–Oppenheimer electronic states as a collective variable, multistate metadynamics trajectories are driven toward an intersection point starting from an arbitrary ground state geometry and are subsequently forced to explore the conical intersection seam landscape. For this purpose, an additional collective variable capable of distinguishing structures within the seam needs to be defined and an additional bias is introduced into the off-diagonal elements of an extended (multistate) electronic Hamiltonian. We demonstrate the performance of the algorithm on the examples of the 1,3-butadiene, benzene, and 9H-adenine molecules, where multiple minimum energy crossing points could be systematically located using the Wiener number or Cremer–Pople parameters as collective variables. Finally, with the example of 9H-adenine, we show that the multistate metadynamics potential can be used to obtain a global picture of a conical intersection seam. Our method can be straightforwardly connected with any ab initio or semiempirical electronic structure theory that provides energies and gradients of the respective electronic states and can serve for systematic elucidation of the role of conical intersections in the photophysics and photochemistry of complex molecular systems, thus complementing nonadiabatic dynamics simulations. KW - Computational Chemistry KW - Metadynamics KW - Hydrogen KW - Hydrocarbons KW - Chemical Structure Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-199258 UR - https://doi.org/10.1021/acs.jctc.9b00029 N1 - This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Chemical Theory and Computation, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see Journal of Chemical Theory and Computation 2019, 15, 6, 3450-3460. https://doi.org/10.1021/acs.jctc.9b00029. ER - TY - JOUR A1 - Jeanclos, Elisabeth A1 - Knobloch, Gunnar A1 - Hoffmann, Axel A1 - Fedorchenko, Oleg A1 - Odersky, Andrea A1 - Lamprecht, Anna‐Karina A1 - Schindelin, Hermann A1 - Gohla, Antje T1 - Ca\(^{2+}\) functions as a molecular switch that controls the mutually exclusive complex formation of pyridoxal phosphatase with CIB1 or calmodulin JF - FEBS Letters N2 - Pyridoxal 5′‐phosphate (PLP) is an essential cofactor for neurotransmitter metabolism. Pyridoxal phosphatase (PDXP) deficiency in mice increases PLP and γ‐aminobutyric acid levels in the brain, yet how PDXP is regulated is unclear. Here, we identify the Ca\(^{2+}\)‐ and integrin‐binding protein 1 (CIB1) as a PDXP interactor by yeast two‐hybrid screening and find a calmodulin (CaM)‐binding motif that overlaps with the PDXP‐CIB1 interaction site. Pulldown and crosslinking assays with purified proteins demonstrate that PDXP directly binds to CIB1 or CaM. CIB1 or CaM does not alter PDXP phosphatase activity. However, elevated Ca\(^{2+}\) concentrations promote CaM binding and, thereby, diminish CIB1 binding to PDXP, as both interactors bind in a mutually exclusive way. Hence, the PDXP‐CIB1 complex may functionally differ from the PDXP‐Ca\(^{2+}\)‐CaM complex. KW - calmodulin KW - chronophin KW - CIB1 KW - haloacid dehalogenase KW - pyridoxal phosphatase KW - vitamin B6 Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-217963 VL - 594 IS - 13 SP - 2099 EP - 2115 ER - TY - JOUR A1 - Dauer née Joppe, Karina A1 - Tatenhorst, Lars A1 - Caldi Gomes, Lucas A1 - Zhang, Shuyu A1 - Parvaz, Mojan A1 - Carboni, Eleonora A1 - Roser, Anna‐Elisa A1 - El DeBakey, Hazem A1 - Bähr, Mathias A1 - Vogel‐Mikuš, Katarina A1 - Wang Ip, Chi A1 - Becker, Stefan A1 - Zweckstetter, Markus A1 - Lingor, Paul T1 - Brain iron enrichment attenuates α‐synuclein spreading after injection of preformed fibrils JF - Journal of Neurochemistry N2 - Regional iron accumulation and α‐synuclein (α‐syn) spreading pathology within the central nervous system are common pathological findings in Parkinson's disease (PD). Whereas iron is known to bind to α‐syn, facilitating its aggregation and regulating α‐syn expression, it remains unclear if and how iron also modulates α‐syn spreading. To elucidate the influence of iron on the propagation of α‐syn pathology, we investigated α‐syn spreading after stereotactic injection of α‐syn preformed fibrils (PFFs) into the striatum of mouse brains after neonatal brain iron enrichment. C57Bl/6J mouse pups received oral gavage with 60, 120, or 240 mg/kg carbonyl iron or vehicle between postnatal days 10 and 17. At 12 weeks of age, intrastriatal injections of 5‐µg PFFs were performed to induce seeding of α‐syn aggregates. At 90 days post‐injection, PFFs‐injected mice displayed long‐term memory deficits, without affection of motor behavior. Interestingly, quantification of α‐syn phosphorylated at S129 showed reduced α‐syn pathology and attenuated spreading to connectome‐specific brain regions after brain iron enrichment. Furthermore, PFFs injection caused intrastriatal microglia accumulation, which was alleviated by iron in a dose‐dependent way. In primary cortical neurons in a microfluidic chamber model in vitro, iron application did not alter trans‐synaptic α‐syn propagation, possibly indicating an involvement of non‐neuronal cells in this process. Our study suggests that α‐syn PFFs may induce cognitive deficits in mice independent of iron. However, a redistribution of α‐syn aggregate pathology and reduction of striatal microglia accumulation in the mouse brain may be mediated via iron‐induced alterations of the brain connectome. KW - alpha‐synuclein KW - alpha‐synuclein propagation KW - alpha‐synuclein seeding KW - iron dyshomeostasis KW - Parkinson's disease Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-262544 VL - 159 IS - 3 SP - 554 EP - 573 ER - TY - JOUR A1 - Kaiser, Anna A1 - Aggensteiner, Pascal-M. A1 - Holtmann, Martin A1 - Fallgatter, Andreas A1 - Romanos, Marcel A1 - Abenova, Karina A1 - Alm, Barbara A1 - Becker, Katja A1 - Döpfner, Manfred A1 - Ethofer, Thomas A1 - Freitag, Christine M. A1 - Geissler, Julia A1 - Hebebrand, Johannes A1 - Huss, Michael A1 - Jans, Thomas A1 - Jendreizik, Lea Teresa A1 - Ketter, Johanna A1 - Legenbauer, Tanja A1 - Philipsen, Alexandra A1 - Poustka, Luise A1 - Renner, Tobias A1 - Retz, Wolfgang A1 - Rösler, Michael A1 - Thome, Johannes A1 - Uebel-von Sandersleben, Henrik A1 - von Wirth, Elena A1 - Zinnow, Toivo A1 - Hohmann, Sarah A1 - Millenet, Sabina A1 - Holz, Nathalie E. A1 - Banaschewski, Tobias A1 - Brandeis, Daniel T1 - EEG data quality: determinants and impact in a multicenter study of children, adolescents, and adults with attention-deficit/hyperactivity disorder (ADHD) JF - Brain Sciences N2 - Electroencephalography (EEG) represents a widely established method for assessing altered and typically developing brain function. However, systematic studies on EEG data quality, its correlates, and consequences are scarce. To address this research gap, the current study focused on the percentage of artifact-free segments after standard EEG pre-processing as a data quality index. We analyzed participant-related and methodological influences, and validity by replicating landmark EEG effects. Further, effects of data quality on spectral power analyses beyond participant-related characteristics were explored. EEG data from a multicenter ADHD-cohort (age range 6 to 45 years), and a non-ADHD school-age control group were analyzed (n\(_{total}\) = 305). Resting-state data during eyes open, and eyes closed conditions, and task-related data during a cued Continuous Performance Task (CPT) were collected. After pre-processing, general linear models, and stepwise regression models were fitted to the data. We found that EEG data quality was strongly related to demographic characteristics, but not to methodological factors. We were able to replicate maturational, task, and ADHD effects reported in the EEG literature, establishing a link with EEG-landmark effects. Furthermore, we showed that poor data quality significantly increases spectral power beyond effects of maturation and symptom severity. Taken together, the current results indicate that with a careful design and systematic quality control, informative large-scale multicenter trials characterizing neurophysiological mechanisms in neurodevelopmental disorders across the lifespan are feasible. Nevertheless, results are restricted to the limitations reported. Future work will clarify predictive value. KW - electroencephalography (EEG) KW - data quality KW - attention-deficit/hyperactivity disorder (ADHD) KW - artifacts KW - multicenter study Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228788 SN - 2076-3425 VL - 11 IS - 2 ER -