TY - JOUR A1 - Koessler, Juergen A1 - Hermann, Stephanie A1 - Weber, Katja A1 - Koessler, Angela A1 - Kuhn, Sabine A1 - Boeck, Markus A1 - Kobsar, Anna T1 - Role of Purinergic Receptor Expression and Function for Reduced Responsiveness to Adenosine Diphosphate in Washed Human Platelets JF - PLoS One N2 - Background Washing of platelets is an important procedure commonly used for experimental studies, e.g. in cardiovascular research. As a known phenomenon, responsiveness to adenosine diphosphate (ADP) is reduced in washed platelets, although underlying molecular mechanisms—potentially interfering with experimental results—have not been thoroughly studied. Objectives Since ADP mediates its effects via three purinergic receptors P2Y1, P2X1 and P2Y12, their surface expression and function were investigated in washed platelets and, for comparison, in platelet-rich-plasma (PRP) at different time points for up to 2 hours after preparation. Results In contrast to PRP, flow cytometric analysis of surface expression in washed platelets revealed an increase of all receptors during the first 60 minutes after preparation followed by a significant reduction, which points to an initial preactivation of platelets and consecutive degeneration. The activity of the P2X1 receptor (measured by selectively induced calcium flux) was substantially maintained in both PRP and washed platelets. P2Y12 function (determined by flow cytometry as platelet reactivity index) was partially reduced after platelet washing compared to PRP, but remained stable in course of ongoing storage. However, the function of the P2Y1 receptor (measured by selectively induced calcium flux) continuously declined after preparation of washed platelets. Conclusion In conclusion, decreasing ADP responsiveness in washed platelets is particularly caused by impaired activity of the P2Y1 receptor associated with disturbed calcium regulation, which has to be considered in the design of experimental studies addressing ADP mediated platelet function. KW - platelets KW - flow cytometry KW - adenosine KW - statistical data KW - platelet activation KW - platelet aggregation KW - phosphorylation KW - blood plasma Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-146400 VL - 11 IS - 1 ER - TY - JOUR A1 - Palige, Katja A1 - Linde, Jörg A1 - Martin, Ronny A1 - Böttcher, Bettina A1 - Citiulo, Francesco A1 - Sullivan, Derek J. A1 - Weber, Johann A1 - Staib, Claudia A1 - Rupp, Steffen A1 - Hube, Bernhard A1 - Morschhäuser, Joachim A1 - Staib, Peter T1 - Global Transcriptome Sequencing Identifies Chlamydospore Specific Markers in Candida albicans and Candida dubliniensis JF - PLoS ONE N2 - Candida albicans and Candida dubliniensis are pathogenic fungi that are highly related but differ in virulence and in some phenotypic traits. During in vitro growth on certain nutrient-poor media, C. albicans and C. dubliniensis are the only yeast species which are able to produce chlamydospores, large thick-walled cells of unknown function. Interestingly, only C. dubliniensis forms pseudohyphae with abundant chlamydospores when grown on Staib medium, while C. albicans grows exclusively as a budding yeast. In order to further our understanding of chlamydospore development and assembly, we compared the global transcriptional profile of both species during growth in liquid Staib medium by RNA sequencing. We also included a C. albicans mutant in our study which lacks the morphogenetic transcriptional repressor Nrg1. This strain, which is characterized by its constitutive pseudohyphal growth, specifically produces masses of chlamydospores in Staib medium, similar to C. dubliniensis. This comparative approach identified a set of putatively chlamydospore-related genes. Two of the homologous C. albicans and C. dubliniensis genes (CSP1 and CSP2) which were most strongly upregulated during chlamydospore development were analysed in more detail. By use of the green fluorescent protein as a reporter, the encoded putative cell wall related proteins were found to exclusively localize to C. albicans and C. dubliniensis chlamydospores. Our findings uncover the first chlamydospore specific markers in Candida species and provide novel insights in the complex morphogenetic development of these important fungal pathogens. KW - NRG1 KW - staib agar KW - gene KW - morphogenesis KW - expression KW - regulator KW - virulence KW - growth KW - UME6 KW - epidemiology Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-131007 VL - 8 IS - 4 ER - TY - JOUR A1 - Jaite, Charlotte A1 - Bühren, Katharina A1 - Dahmen, Brigitte A1 - Dempfle, Astrid A1 - Becker, Katja A1 - Correll, Christoph U. A1 - Egberts, Karin M. A1 - Ehrlich, Stefan A1 - Fleischhaker, Christian A1 - von Gontard, Alexander A1 - Hahn, Freia A1 - Kolar, David A1 - Kaess, Michael A1 - Legenbauer, Tanja A1 - Renner, Tobias J. A1 - Schulze, Ulrike A1 - Sinzig, Judith A1 - Thomae, Ellen A1 - Weber, Linda A1 - Wessing, Ida A1 - Antony, Gisela A1 - Hebebrand, Johannes A1 - Föcker, Manuel A1 - Herpertz-Dahlmann, Beate T1 - Clinical Characteristics of Inpatients with Childhood vs. Adolescent Anorexia Nervosa JF - Nutrients N2 - We aimed to compare the clinical data at first presentation to inpatient treatment of children (<14 years) vs. adolescents (≥14 years) with anorexia nervosa (AN), focusing on duration of illness before hospital admission and body mass index (BMI) at admission and discharge, proven predictors of the outcomes of adolescent AN. Clinical data at first admission and at discharge in 289 inpatients with AN (children: n = 72; adolescents: n = 217) from a German multicenter, web-based registry for consecutively enrolled patients with childhood and adolescent AN were analyzed. Inclusion criteria were a maximum age of 18 years, first inpatient treatment due to AN, and a BMI <10th BMI percentile at admission. Compared to adolescents, children with AN had a shorter duration of illness before admission (median: 6.0 months vs. 8.0 months, p = 0.004) and higher BMI percentiles at admission (median: 0.7 vs. 0.2, p = 0.004) as well as at discharge (median: 19.3 vs. 15.1, p = 0.011). Thus, in our study, children with AN exhibited clinical characteristics that have been associated with better outcomes, including higher admission and discharge BMI percentile. Future studies should examine whether these factors are actually associated with positive long-term outcomes in children. KW - anorexia nervosa KW - children KW - adolescents KW - clinical characteristics KW - BMI KW - outcome Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-193160 SN - 2072-6643 VL - 11 IS - 11 ER - TY - JOUR A1 - Kobsar, Anna A1 - Koehnlechner, Karina A1 - Klingler, Philipp A1 - Niklaus, Marius A1 - Zeller-Hahn, Julia A1 - Koessler, Angela A1 - Weber, Katja A1 - Boeck, Markus A1 - Koessler, Juergen T1 - The effect of short-term refrigeration on platelet responsiveness JF - Scientific Reports N2 - Storage of platelet concentrates (PC) at cold temperature (CT) is discussed as an alternative to the current standard of storage at room temperature (RT). Recently, we could show that cold-induced attenuation of inhibitory signaling is an important mechanism promoting platelet reactivity. For developing strategies in blood banking, it is required to elucidate the time-dependent onset of facilitated platelet activation. Thus, freshly prepared platelet-rich-plasma (PRP) was stored for 1 and 2 h at CT (2–6 °C) or at RT (20–24 °C), followed by subsequent comparative analysis. Compared to RT, basal and induced vasodilator-stimulated phosphoprotein (VASP) phosphorylation levels were decreased under CT within 1 h by approximately 20%, determined by Western blot analysis and flow cytometry. Concomitantly, ADP- and collagen-induced threshold aggregation values were enhanced by up to 30–40%. Furthermore, platelet-covered areas on collagen-coated slides and aggregate formation under flow conditions were increased after storage at CT, in addition to induced activation markers. In conclusion, a time period of 1–2 h for refrigeration is sufficient to induce an attenuation of inhibitory signaling, accompanied with an enhancement of platelet responsiveness. Short-term refrigeration may be considered as a rational approach to obtain PC with higher functional reactivity for the treatment of hemorrhage. KW - short‑term refrigeration KW - platelet responsiveness KW - cold temperature Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-301390 VL - 12 IS - 1 ER - TY - JOUR A1 - Koessler, Juergen A1 - Klingler, Philipp A1 - Niklaus, Marius A1 - Weber, Katja A1 - Koessler, Angela A1 - Boeck, Markus A1 - Kobsar, Anna T1 - The Impact of Cold Storage on Adenosine Diphosphate-Mediated Platelet Responsiveness JF - TH Open N2 - Introduction  Cold storage of platelets is considered to contribute to lower risk of bacterial growth and to more efficient hemostatic capacity. For the optimization of storage strategies, it is required to further elucidate the influence of refrigeration on platelet integrity. This study focused on adenosine diphosphate (ADP)-related platelet responsiveness. Materials and Methods  Platelets were prepared from apheresis-derived platelet concentrates or from peripheral whole blood, stored either at room temperature or at 4°C. ADP-induced aggregation was tested with light transmission. Activation markers, purinergic receptor expression, and P2Y12 receptor function were determined by flow cytometry. P2Y1 and P2X1 function was assessed by fluorescence assays, cyclic nucleotide concentrations by immunoassays, and vasodilator-stimulated phosphoprotein (VASP)-phosphorylation levels by Western blot analysis. Results  In contrast to room temperature, ADP-induced aggregation was maintained under cold storage for 6 days, associated with elevated activation markers like fibrinogen binding or CD62P expression. Purinergic receptor expression was not essentially different, whereas P2Y1 function deteriorated rapidly at cold storage, but not P2Y12 activity. Inhibitory pathways of cold-stored platelets were characterized by reduced responses to nitric oxide and prostaglandin E1. Refrigeration of citrated whole blood also led to the attenuation of induced inhibition of platelet aggregation, detectable within 24 hours. Conclusion  ADP responsiveness is preserved under cold storage for 6 days due to stable P2Y12 activity and concomitant disintegration of inhibitory pathways enabling a higher reactivity of stored platelets. The ideal storage time at cold temperature for the highest hemostatic effect of platelets should be evaluated in further studies. KW - platelet physiology KW - cold storage KW - adenosine diphosphate KW - purinergic receptors KW - inhibitory signaling Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-229387 VL - 4 IS - 3 ER - TY - JOUR A1 - Niklaus, Marius A1 - Klingler, Philipp A1 - Weber, Katja A1 - Koessler, Angela A1 - Kuhn, Sabine A1 - Boeck, Markus A1 - Kobsar, Anna A1 - Koessler, Juergen T1 - Platelet Toll-Like-Receptor-2 and -4 Mediate Different Immune-Related Responses to Bacterial Ligands JF - TH Open N2 - Background  Like immune cells, platelets express toll-like receptors (TLRs) on their surface membrane. TLR2 and TLR4 are able to recognize bacterial antigens and have the potential to influence hemostatic functions and classical intracellular signaling pathways. This study investigated the role of TLR2 and TLR4 for immune-related functions in human platelets. Materials and Methods  Washed platelets and neutrophils were prepared from fresh human peripheral blood. Basal-, Pam3CSK4- (as TLR2 agonist) and Lipopolysaccharides (LPS; as TLR4 agonist) -induced CD62P expression, fibrinogen binding and TLR2 or TLR4 expression, intracellular reactive oxygen species (ROS) production in H2DCFDA-loaded platelets and uptake of fluorescence-labeled TLR ligands, and fluorophore-conjugated fibrinogen were evaluated by flow cytometry. Analysis of platelet–neutrophil complexes was performed after coincubation of washed platelets and neutrophils in the presence and absence of TLR2 or TLR4 agonists on poly-L-lysine coated surfaces, followed by immunostaining and immunofluorescence imaging. Results  Pam3CSK4 rapidly and transiently increased TLR2 and TLR4 expression. Over the course of 30 minutes after activation with Pam3CSK4 and LPS, the expression of both receptors decreased. Pam3CSK4-stimulated intracellular ROS production and the uptake of TLR ligands or fibrinogen much stronger than LPS. Besides, TLR4 activation led to a significant increase of platelet–neutrophil contacts. Conclusion  Stimulation leads to rapid mobilization of TLR2 or TLR4 to the platelet surface, presumably followed by receptor internalization along with bound TLR ligands. After activation, platelet TLR2 and TLR4 mediate different immune-related reactions. In particular, TLR2 induces intracellular responses in platelets, whereas TLR4 initiates interactions with other immune cells such as neutrophils. KW - receptors KW - immunity KW - cell-cell interactions KW - platelet physiology Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-301401 VL - 6 IS - 3 SP - e156 EP - e167 ER - TY - JOUR A1 - Koessler, Juergen A1 - Schwarz, Michaela A1 - Weber, Katja A1 - Etzel, Julia A1 - Koessler, Angela A1 - Boeck, Markus A1 - Kobsar, Anna T1 - The role of adenosine diphosphate mediated platelet responsiveness for the stability of platelet integrity in citrated whole blood under ex vivo conditions JF - PLoS ONE N2 - Background: Platelets are important for effective hemostasis and considered to be involved in pathophysiological processes, e.g. in cardiovascular diseases. Platelets provided for research or for therapeutic use are frequently separated from citrated whole blood (WB) stored for different periods of time. Although functionally intact platelets are required, the stability of platelet integrity, e.g. adenosine diphosphate (ADP) mediated responsiveness, has never been thoroughly investigated in citrated WB under ex vivo conditions. Objectives: Platelet integrity was evaluated at different time points in citrated WB units, collected from healthy donors and stored for 5 days at ambient temperature. The analysis included the measurement of activation markers, of induced light transmission aggregometry and of purinergic receptor expression or function. Inhibitory pathways were explored by determination of basal vasodilator-stimulated phosphoprotein (VASP)-phosphorylation, intracellular cyclic nucleotide levels and the content of phosphodiesterase 5A. Fresh peripheral blood (PB) samples served as controls. Results: On day 5 of storage, thrombin receptor activating peptide-6 (TRAP-6) stimulated CD62P expression and fibrinogen binding were comparable to PB samples. ADP induced aggregation continuously decreased during storage. Purinergic receptor expression remained unchanged, whereas the P2Y1 activity progressively declined in contrast to preserved P2Y12 and P2X1 function. Inhibitory pathways were unaffected except for a slight elevation of VASP phosphorylation at Ser\(^{239}\) on day 5. Conclusion: After 5 days of storage in citrated WB, platelet responsiveness to TRAP-6 is sufficiently maintained. However, ADP-mediated platelet integrity is more sensitive to deterioration, especially after storage for more than 2 days. Decreasing ADP-induced aggregation is particularly caused by the impairment of the purinergic receptor P2Y1 activity. These characteristics should be considered in the use of platelets from stored citrated WB for experimental or therapeutic issues. KW - fibrinogen KW - phosphorylation KW - platelets KW - blood KW - specimen storage KW - flow cytometry Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-159879 VL - 12 IS - 11 ER - TY - JOUR A1 - Traub, Jan A1 - Grondey, Katja A1 - Gassenmaier, Tobias A1 - Schmitt, Dominik A1 - Fette, Georg A1 - Frantz, Stefan A1 - Boivin-Jahns, Valérie A1 - Jahns, Roland A1 - Störk, Stefan A1 - Stoll, Guido A1 - Reiter, Theresa A1 - Hofmann, Ulrich A1 - Weber, Martin S. A1 - Frey, Anna T1 - Sustained increase in serum glial fibrillary acidic protein after first ST-elevation myocardial infarction JF - International Journal of Molecular Sciences N2 - Acute ischemic cardiac injury predisposes one to cognitive impairment, dementia, and depression. Pathophysiologically, recent positron emission tomography data suggest astroglial activation after experimental myocardial infarction (MI). We analyzed peripheral surrogate markers of glial (and neuronal) damage serially within 12 months after the first ST-elevation MI (STEMI). Serum levels of glial fibrillary acidic protein (GFAP) and neurofilament light chain (NfL) were quantified using ultra-sensitive molecular immunoassays. Sufficient biomaterial was available from 45 STEMI patients (aged 28 to 78 years, median 56 years, 11% female). The median (quartiles) of GFAP was 63.8 (47.0, 89.9) pg/mL and of NfL 10.6 (7.2, 14.8) pg/mL at study entry 0–4 days after STEMI. GFAP after STEMI increased in the first 3 months, with a median change of +7.8 (0.4, 19.4) pg/mL (p = 0.007). It remained elevated without further relevant increases after 6 months (+11.7 (0.6, 23.5) pg/mL; p = 0.015), and 12 months (+10.3 (1.5, 22.7) pg/mL; p = 0.010) compared to the baseline. Larger relative infarction size was associated with a higher increase in GFAP (ρ = 0.41; p = 0.009). In contrast, NfL remained unaltered in the course of one year. Our findings support the idea of central nervous system involvement after MI, with GFAP as a potential peripheral biomarker of chronic glial damage as one pathophysiologic pathway. KW - myocardial infarction KW - STEMI KW - glial fibrillary acidic protein KW - GFAP KW - neurofilament light chain KW - NfL KW - glial damage KW - cardiac magnetic resonance imaging KW - MRI KW - infarction size Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-288261 SN - 1422-0067 VL - 23 IS - 18 ER - TY - JOUR A1 - Gröbner, Susanne N. A1 - Worst, Barbara C. A1 - Weischenfeldt, Joachim A1 - Buchhalter, Ivo A1 - Kleinheinz, Kortine A1 - Rudneva, Vasilisa A. A1 - Johann, Pascal D. A1 - Balasubramanian, Gnana Prakash A1 - Segura-Wang, Maia A1 - Brabetz, Sebastian A1 - Bender, Sebastian A1 - Hutter, Barbara A1 - Sturm, Dominik A1 - Pfaff, Elke A1 - Hübschmann, Daniel A1 - Zipprich, Gideon A1 - Heinold, Michael A1 - Eils, Jürgen A1 - Lawerenz, Christian A1 - Erkek, Serap A1 - Lambo, Sander A1 - Waszak, Sebastian A1 - Blattmann, Claudia A1 - Borkhardt, Arndt A1 - Kuhlen, Michaela A1 - Eggert, Angelika A1 - Fulda, Simone A1 - Gessler, Manfred A1 - Wegert, Jenny A1 - Kappler, Roland A1 - Baumhoer, Daniel A1 - Stefan, Burdach A1 - Kirschner-Schwabe, Renate A1 - Kontny, Udo A1 - Kulozik, Andreas E. A1 - Lohmann, Dietmar A1 - Hettmer, Simone A1 - Eckert, Cornelia A1 - Bielack, Stefan A1 - Nathrath, Michaela A1 - Niemeyer, Charlotte A1 - Richter, Günther H. A1 - Schulte, Johannes A1 - Siebert, Reiner A1 - Westermann, Frank A1 - Molenaar, Jan J. A1 - Vassal, Gilles A1 - Witt, Hendrik A1 - Burkhardt, Birgit A1 - Kratz, Christian P. A1 - Witt, Olaf A1 - van Tilburg, Cornelis M. A1 - Kramm, Christof M. A1 - Fleischhack, Gudrun A1 - Dirksen, Uta A1 - Rutkowski, Stefan A1 - Frühwald, Michael A1 - Hoff, Katja von A1 - Wolf, Stephan A1 - Klingebeil, Thomas A1 - Koscielniak, Ewa A1 - Landgraf, Pablo A1 - Koster, Jan A1 - Resnick, Adam C. A1 - Zhang, Jinghui A1 - Liu, Yanling A1 - Zhou, Xin A1 - Waanders, Angela J. A1 - Zwijnenburg, Danny A. A1 - Raman, Pichai A1 - Brors, Benedikt A1 - Weber, Ursula D. A1 - Northcott, Paul A. A1 - Pajtler, Kristian W. A1 - Kool, Marcel A1 - Piro, Rosario M. A1 - Korbel, Jan O. A1 - Schlesner, Matthias A1 - Eils, Roland A1 - Jones, David T. W. A1 - Lichter, Peter A1 - Chavez, Lukas A1 - Zapatka, Marc A1 - Pfister, Stefan M. T1 - The landscape of genomic alterations across childhood cancers JF - Nature N2 - Pan-cancer analyses that examine commonalities and differences among various cancer types have emerged as a powerful way to obtain novel insights into cancer biology. Here we present a comprehensive analysis of genetic alterations in a pan-cancer cohort including 961 tumours from children, adolescents, and young adults, comprising 24 distinct molecular types of cancer. Using a standardized workflow, we identified marked differences in terms of mutation frequency and significantly mutated genes in comparison to previously analysed adult cancers. Genetic alterations in 149 putative cancer driver genes separate the tumours into two classes: small mutation and structural/copy-number variant (correlating with germline variants). Structural variants, hyperdiploidy, and chromothripsis are linked to TP53 mutation status and mutational signatures. Our data suggest that 7–8% of the children in this cohort carry an unambiguous predisposing germline variant and that nearly 50% of paediatric neoplasms harbour a potentially druggable event, which is highly relevant for the design of future clinical trials. KW - cancer genomics KW - oncogenesis KW - paediatric cancer KW - predictive markers KW - translational research Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-229579 VL - 555 ER -