@article{ThalSmetakHayashietal.2022, author = {Thal, Serge C. and Smetak, Manuel and Hayashi, Kentaro and F{\"o}rster, Carola Y.}, title = {Hemorrhagic cerebral insults and secondary Takotsubo syndrome: findings in a novel in vitro model using human blood samples}, series = {International Journal of Molecular Sciences}, volume = {23}, journal = {International Journal of Molecular Sciences}, number = {19}, issn = {1422-0067}, doi = {10.3390/ijms231911557}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-288305}, year = {2022}, abstract = {Intracranial hemorrhage results in devastating forms of cerebral damage. Frequently, these results also present with cardiac dysfunction ranging from ECG changes to Takotsubo syndrome (TTS). This suggests that intracranial bleeding due to subarachnoid hemorrhage (SAH) disrupts the neuro-cardiac axis leading to neurogenic stress cardiomyopathy (NSC) of different degrees. Following this notion, SAH and secondary TTS could be directly linked, thus contributing to poor outcomes. We set out to test if blood circulation is the driver of the brain-heart axis by investigating serum samples of TTS patients. We present a novel in vitro model combining SAH and secondary TTS to mimic the effects of blood or serum, respectively, on blood-brain barrier (BBB) integrity using in vitro monolayers of an established murine model. We consistently demonstrated decreased monolayer integrity and confirmed reduced Claudin-5 and Occludin levels by RT-qPCR and Western blot and morphological reorganization of actin filaments in endothelial cells. Both tight junction proteins show a time-dependent reduction. Our findings highlight a faster and more prominent disintegration of BBB in the presence of TTS and support the importance of the bloodstream as a causal link between intracerebral bleeding and cardiac dysfunction. This may represent potential targets for future therapeutic inventions in SAH and TTS.}, language = {en} } @article{IbrahimOhlsen2022, author = {Ibrahim, Eslam S. and Ohlsen, Knut}, title = {The old yellow enzyme OfrA fosters Staphylococcus aureus survival via affecting thiol-dependent redox homeostasis}, series = {Frontiers in Microbiology}, volume = {13}, journal = {Frontiers in Microbiology}, issn = {1664-302X}, doi = {10.3389/fmicb.2022.888140}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-274381}, year = {2022}, abstract = {Old yellow enzymes (OYEs) are widely found in the bacterial, fungal, and plant kingdoms but absent in humans and have been used as biocatalysts for decades. However, OYEs' physiological function in bacterial stress response and infection situations remained enigmatic. As a pathogen, the Gram-positive bacterium Staphylococcus aureus adapts to numerous stress conditions during pathogenesis. Here, we show that in S. aureus genome, two paralogous genes (ofrA and ofrB) encode for two OYEs. We conducted a bioinformatic analysis and found that ofrA is conserved among all publicly available representative staphylococcal genomes and some Firmicutes. Expression of ofrA is induced by electrophilic, oxidative, and hypochlorite stress in S. aureus. Furthermore, ofrA contributes to S. aureus survival against reactive electrophilic, oxygen, and chlorine species (RES, ROS, and RCS) via thiol-dependent redox homeostasis. At the host-pathogen interface, S. aureusΔofrA has defective survival in macrophages and whole human blood and decreased staphyloxanthin production. Overall, our results shed the light onto a novel stress response strategy in the important human pathogen S. aureus.}, language = {en} } @article{BochSpiessHeinzetal.2019, author = {Boch, Tobias and Spiess, Birgit and Heinz, Werner and Cornely, Oliver A. and Schwerdtfeger, Rainer and Hahn, Joachim and Krause, Stefan W. and Duerken, Matthias and Bertz, Hartmut and Reuter, Stefan and Kiehl, Michael and Claus, Bernd and Deckert, Peter Markus and Hofmann, Wolf-Karsten and Buchheidt, Dieter and Reinwald, Mark}, title = {Aspergillus specific nested PCR from the site of infection is superior to testing concurrent blood samples in immunocompromised patients with suspected invasive aspergillosis}, series = {Mycoses}, volume = {62}, journal = {Mycoses}, number = {11}, doi = {10.1111/myc.12983}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-214065}, pages = {1035 -- 1042}, year = {2019}, abstract = {Invasive aspergillosis (IA) is a severe complication in immunocompromised patients. Early diagnosis is crucial to decrease its high mortality, yet the diagnostic gold standard (histopathology and culture) is time-consuming and cannot offer early confirmation of IA. Detection of IA by polymerase chain reaction (PCR) shows promising potential. Various studies have analysed its diagnostic performance in different clinical settings, especially addressing optimal specimen selection. However, direct comparison of different types of specimens in individual patients though essential, is rarely reported. We systematically assessed the diagnostic performance of an Aspergillus-specific nested PCR by investigating specimens from the site of infection and comparing it with concurrent blood samples in individual patients (pts) with IA. In a retrospective multicenter analysis PCR was performed on clinical specimens (n = 138) of immunocompromised high-risk pts (n = 133) from the site of infection together with concurrent blood samples. 38 pts were classified as proven/probable, 67 as possible and 28 as no IA according to 2008 European Organization for Research and Treatment of Cancer/Mycoses Study Group consensus definitions. A considerably superior performance of PCR from the site of infection was observed particularly in pts during antifungal prophylaxis (AFP)/antifungal therapy (AFT). Besides a specificity of 85\%, sensitivity varied markedly in BAL (64\%), CSF (100\%), tissue samples (67\%) as opposed to concurrent blood samples (8\%). Our results further emphasise the need for investigating clinical samples from the site of infection in case of suspected IA to further establish or rule out the diagnosis.}, language = {en} } @article{HaertleMaierhoferBoecketal.2017, author = {Haertle, Larissa and Maierhofer, Anna and B{\"o}ck, Julia and Lehnen, Harald and B{\"o}ttcher, Yvonne and Bl{\"u}her, Matthias and Schorsch, Martin and Potabattula, Ramya and El Hajj, Nady and Appenzeller, Silke and Haaf, Thomas}, title = {Hypermethylation of the non-imprinted maternal MEG3 and paternal MEST alleles is highly variable among normal individuals}, series = {PLoS ONE}, volume = {12}, journal = {PLoS ONE}, number = {8}, doi = {10.1371/journal.pone.0184030}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170433}, pages = {e0184030}, year = {2017}, abstract = {Imprinted genes show parent-specific activity (functional haploidy), which makes them particularly vulnerable to epigenetic dysregulation. Here we studied the methylation profiles of oppositely imprinted genes at single DNA molecule resolution by two independent parental allele-specific deep bisulfite sequencing (DBS) techniques. Using Roche (GSJunior) next generation sequencing technology, we analyzed the maternally imprinted MEST promoter and the paternally imprinted MEG3 intergenic (IG) differentially methylated region (DMR) in fetal cord blood, adult blood, and visceral adipose tissue. Epimutations were defined as paternal or maternal alleles with >50\% aberrantly (de)methylated CpG sites, showing the wrong methylation imprint. The epimutation rates (range 2-66\%) of the paternal MEST and the maternal MEG3 IG DMR allele, which should be completely unmethylated, were significantly higher than those (0-15\%) of the maternal MEST and paternal MEG3 alleles, which are expected to be fully methylated. This hypermethylation of the non-imprinted allele (HNA) was independent of parental origin. Very low epimutation rates in sperm suggest that HNA occurred after fertilization. DBS with Illumina (MiSeq) technology confirmed HNA for the MEST promoter and the MEG3 IG DMR, and to a lesser extent, for the paternally imprinted secondary MEG3 promoter and the maternally imprinted PEG3 promoter. HNA leads to biallelic methylation of imprinted genes in a considerable proportion of normal body cells (somatic mosaicism) and is highly variable between individuals. We propose that during development and differentiation maintenance of differential methylation at most imprinting control regions may become to some extent redundant. The accumulation of stochastic and environmentally-induced methylation errors on the non-imprinted allele may increase epigenetic diversity between cells and individuals.}, language = {en} } @article{SchumannEberleinMuhtadietal.2018, author = {Schumann, Sarah and Eberlein, Uta and Muhtadi, Razan and Lassmann, Michael and Scherthan, Harry}, title = {DNA damage in leukocytes after internal ex-vivo irradiation of blood with the α-emitter Ra-223}, series = {Scientific Reports}, volume = {8}, journal = {Scientific Reports}, number = {2286}, doi = {10.1038/s41598-018-20364-7}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-175596}, year = {2018}, abstract = {Irradiation with high linear energy transfer α-emitters, like the clinically used Ra-223 dichloride, severely damages cells and induces complex DNA damage including closely spaced double-strand breaks (DSBs). As the hematopoietic system is an organ-at-risk for the treatment, knowledge about Ra-223-induced DNA damage in blood leukocytes is highly desirable. Therefore, 36 blood samples from six healthy volunteers were exposed ex-vivo (in solution) to different concentrations of Ra-223. Absorbed doses to the blood were calculated assuming local energy deposition of all α- and β-particles of the decay, ranging from 0 to 142 mGy. γ-H2AX + 53BP1 co-staining and analysis was performed in leukocytes isolated from the irradiated blood samples. For DNA damage quantification, leukocyte samples were screened for occurrence of α-induced DNA damage tracks and small γ-H2AX + 53BP1 DSB foci. This revealed a linear relationship between the frequency of α-induced γ-H2AX damage tracks and the absorbed dose to the blood, while the frequency of small γ-H2AX + 53BP1 DSB foci indicative of β-irradiation was similar to baseline values, being in agreement with a negligible β-contribution (3.7\%) to the total absorbed dose to the blood. Our calibration curve will contribute to the biodosimetry of Ra-223-treated patients and early after incorporation of α-emitters.}, language = {en} } @article{KoesslerSchwarzWeberetal.2017, author = {Koessler, Juergen and Schwarz, Michaela and Weber, Katja and Etzel, Julia and Koessler, Angela and Boeck, Markus and Kobsar, Anna}, title = {The role of adenosine diphosphate mediated platelet responsiveness for the stability of platelet integrity in citrated whole blood under ex vivo conditions}, series = {PLoS ONE}, volume = {12}, journal = {PLoS ONE}, number = {11}, doi = {10.1371/journal.pone.0188193}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-159879}, pages = {e0188193}, year = {2017}, abstract = {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.}, language = {en} } @article{KlughammerDittrichBlometal.2017, author = {Klughammer, Johanna and Dittrich, Marcus and Blom, Jochen and Mitesser, Vera and Vogel, Ulrich and Frosch, Matthias and Goesmann, Alexander and M{\"u}ller, Tobias and Schoen, Christoph}, title = {Comparative genome sequencing reveals within-host genetic changes in Neisseria meningitidis during invasive disease}, series = {PLoS ONE}, volume = {12}, journal = {PLoS ONE}, number = {1}, doi = {10.1371/journal.pone.0169892}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-159547}, pages = {e0169892}, year = {2017}, abstract = {Some members of the physiological human microbiome occasionally cause life-threatening disease even in immunocompetent individuals. A prime example of such a commensal pathogen is Neisseria meningitidis, which normally resides in the human nasopharynx but is also a leading cause of sepsis and epidemic meningitis. Using N. meningitidis as model organism, we tested the hypothesis that virulence of commensal pathogens is a consequence of within host evolution and selection of invasive variants due to mutations at contingency genes, a mechanism called phase variation. In line with the hypothesis that phase variation evolved as an adaptation to colonize diverse hosts, computational comparisons of all 27 to date completely sequenced and annotated meningococcal genomes retrieved from public databases showed that contingency genes are indeed enriched for genes involved in host interactions. To assess within-host genetic changes in meningococci, we further used ultra-deep whole-genome sequencing of throat-blood strain pairs isolated from four patients suffering from invasive meningococcal disease. We detected up to three mutations per strain pair, affecting predominantly contingency genes involved in type IV pilus biogenesis. However, there was not a single (set) of mutation(s) that could invariably be found in all four pairs of strains. Phenotypic assays further showed that these genetic changes were generally not associated with increased serum resistance, higher fitness in human blood ex vivo or differences in the interaction with human epithelial and endothelial cells in vitro. In conclusion, we hypothesize that virulence of meningococci results from accidental emergence of invasive variants during carriage and without within host evolution of invasive phenotypes during disease progression in vivo.}, language = {en} } @article{RadakovicReboredoHelmetal.2017, author = {Radakovic, D. and Reboredo, J. and Helm, M. and Weigel, T. and Sch{\"u}rlein, S. and Kupczyk, E. and Leyh, R. G. and Walles, H. and Hansmann, J.}, title = {A multilayered electrospun graft as vascular access for hemodialysis}, series = {PLoS ONE}, volume = {12}, journal = {PLoS ONE}, number = {10}, doi = {10.1371/journal.pone.0185916}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-159102}, pages = {e0185916}, year = {2017}, abstract = {Despite medical achievements, the number of patients with end-stage kidney disease keeps steadily raising, thereby entailing a high number of surgical and interventional procedures to establish and maintain arteriovenous vascular access for hemodialysis. Due to vascular disease, aneurysms or infection, the preferred access—an autogenous arteriovenous fistula—is not always available and appropriate. Moreover, when replacing small diameter blood vessels, synthetic vascular grafts possess well-known disadvantages. A continuous multilayered gradient electrospinning was used to produce vascular grafts made of collagen type I nanofibers on luminal and adventitial graft side, and poly-ɛ-caprolactone as medial layer. Therefore, a custom-made electrospinner with robust environmental control was developed. The morphology of electrospun grafts was characterized by scanning electron microscopy and measurement of mechanical properties. Human microvascular endothelial cells were cultured in the graft under static culture conditions and compared to cultures obtained from dynamic continuous flow bioreactors. Immunofluorescent analysis showed that endothelial cells form a continuous luminal layer and functional characteristics were confirmed by uptake of acetylated low-density-lipoprotein. Incorporation of vancomycin and gentamicin to the medial graft layer allowed antimicrobial inhibition without exhibiting an adverse impact on cell viability. Most striking a physiological hemocompatibility was achieved for the multilayered grafts.}, language = {en} } @article{KollgaardUgurelBeckerIdornetal.2015, author = {K{\o}llgaard, Tania and Ugurel-Becker, Selma and Idorn, Manja and Andersen, Mads Hald and Becker, J{\"u}rgen C. and Straten, Per thor}, title = {Pre-Vaccination Frequencies of Th17 Cells Correlate with Vaccine-Induced T-Cell Responses to Survivin-Derived Peptide Epitopes}, series = {PLoS One}, volume = {10}, journal = {PLoS One}, number = {7}, doi = {10.1371/journal.pone.0131934}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-151509}, pages = {e0131934}, year = {2015}, abstract = {Various subsets of immune regulatory cells are suggested to influence the outcome of therapeutic antigen-specific anti-tumor vaccinations. We performed an exploratory analysis of a possible correlation of pre-vaccination Th17 cells, MDSCs, and Tregs with both vaccination-induced T-cell responses as well as clinical outcome in metastatic melanoma patients vaccinated with survivin-derived peptides. Notably, we observed dysfunctional Th1 and cytotoxic T cells, i.e. down-regulation of the CD3\(\zeta\)chain (p=0.001) and an impaired IFN\(\gamma\)-production (p=0.001) in patients compared to healthy donors, suggesting an altered activity of immune regulatory cells. Moreover, the frequencies of Th17 cells (p=0.03) and Tregs (p=0.02) were elevated as compared to healthy donors. IL-17-secreting CD4\(^{+}\) T cells displayed an impact on the immunological and clinical effects of vaccination: Patients characterized by high frequencies of Th17 cells at pre-vaccination were more likely to develop survivin-specific T-cell reactivity post-vaccination (p=0.03). Furthermore, the frequency of Th17 (p=0.09) and Th17/IFN\(\gamma\)\(^{+}\) (p=0.19) cells associated with patient survival after vaccination. In summary, our explorative, hypothesis-generating study demonstrated that immune regulatory cells, in particular Th17 cells, play a relevant role for generation of the vaccine-induced anti-tumor immunity in cancer patients, hence warranting further investigation to test for validity as predictive biomarkers.}, language = {en} } @article{BargulJungMcOdimbaetal.2016, author = {Bargul, Joel L. and Jung, Jamin and McOdimba, Francis A. and Omogo, Collins O. and Adung'a, Vincent O. and Kr{\"u}ger, Timothy and Masiga, Daniel K. and Engstler, Markus}, title = {Species-Specific Adaptations of Trypanosome Morphology and Motility to the Mammalian Host}, series = {PLoS Pathogens}, volume = {12}, journal = {PLoS Pathogens}, number = {2}, doi = {10.1371/journal.ppat.1005448}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-146513}, pages = {e1005448}, year = {2016}, abstract = {African trypanosomes thrive in the bloodstream and tissue spaces of a wide range of mammalian hosts. Infections of cattle cause an enormous socio-economic burden in sub-Saharan Africa. A hallmark of the trypanosome lifestyle is the flagellate's incessant motion. This work details the cell motility behavior of the four livestock-parasites Trypanosoma vivax, T. brucei, T. evansi and T. congolense. The trypanosomes feature distinct swimming patterns, speeds and flagellar wave frequencies, although the basic mechanism of flagellar propulsion is conserved, as is shown by extended single flagellar beat analyses. Three-dimensional analyses of the trypanosomes expose a high degree of dynamic pleomorphism, typified by the 'cellular waveform'. This is a product of the flagellar oscillation, the chirality of the flagellum attachment and the stiffness of the trypanosome cell body. The waveforms are characteristic for each trypanosome species and are influenced by changes of the microenvironment, such as differences in viscosity and the presence of confining obstacles. The distinct cellular waveforms may be reflective of the actual anatomical niches the parasites populate within their mammalian host. T. vivax displays waveforms optimally aligned to the topology of the bloodstream, while the two subspecies T. brucei and T. evansi feature distinct cellular waveforms, both additionally adapted to motion in more confined environments such as tissue spaces. T. congolense reveals a small and stiff waveform, which makes these parasites weak swimmers and destined for cell adherence in low flow areas of the circulation. Thus, our experiments show that the differential dissemination and annidation of trypanosomes in their mammalian hosts may depend on the distinct swimming capabilities of the parasites.}, language = {en} }