TY - JOUR A1 - Kurotschka, Peter Konstantin A1 - Tiedemann, Elena A1 - Wolf, Dominik A1 - Thier, Nicola A1 - Forster, Johannes A1 - Liese, Johannes G. A1 - Gagyor, Ildiko T1 - Management of common infections in German primary care: a cross-sectional survey of knowledge and confidence among General Practitioners and outpatient pediatricians JF - Antibiotics N2 - Outpatient antibiotic use is closely related to antimicrobial resistance and in Germany, almost 70% of antibiotic prescriptions in human health are issued by primary care physicians (PCPs). The aim of this study was to explore PCPs, namely General Practitioners' (GPs) and outpatient pediatricians' (PDs) knowledge of guideline recommendations on rational antimicrobial treatment, the determinants of confidence in treatment decisions and the perceived need for training in this topic in a large sample of PCPs from southern Germany. Out of 3753 reachable PCPs, 1311 completed the survey (overall response rate = 34.9%). Knowledge of guideline recommendations and perceived confidence in making treatment decisions were high in both GPs and PDs. The two highest rated influencing factors on prescribing decisions were reported to be guideline recommendations and own clinical experiences, hence patients' demands and expectations were judged as not influencing treatment decisions. The majority of physicians declared to have attended at least one specific training course on antibiotic use, yet almost all the participating PCPs declared to need more training on this topic. More studies are needed to explore how consultation-related and context-specific factors could influence antibiotic prescriptions in general and pediatric primary care in Germany beyond knowledge. Moreover, efforts should be undertaken to explore the training needs of PCPs in Germany, as this would serve the development of evidence-based educational interventions targeted to the improvement of antibiotic prescribing decisions rather than being focused solely on knowledge of guidelines. KW - infectious diseases management KW - general practitioner KW - pediatrician KW - primary care KW - outpatient KW - antibiotic use KW - antimicrobial resistance KW - antimicrobial stewardship KW - survey KW - knowledge Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-246272 SN - 2079-6382 VL - 10 IS - 9 ER - TY - JOUR A1 - Schoen, Christoph A1 - Kischkies, Laura A1 - Elias, Johannes A1 - Ampattu, Biju Joseph T1 - Metabolism and virulence in Neisseria meningitidis N2 - A longstanding question in infection biology addresses the genetic basis for invasive behavior in commensal pathogens. A prime example for such a pathogen is Neisseria meningitidis. On the one hand it is a harmless commensal bacterium exquisitely adapted to humans, and on the other hand it sometimes behaves like a ferocious pathogen causing potentially lethal disease such as sepsis and acute bacterial meningitis. Despite the lack of a classical repertoire of virulence genes in N. meningitidis separating commensal from invasive strains, molecular epidemiology suggests that carriage and invasive strains belong to genetically distinct populations. In recent years, it has become increasingly clear that metabolic adaptation enables meningococci to exploit host resources, supporting the concept of nutritional virulence as a crucial determinant of invasive capability. Here, we discuss the contribution of core metabolic pathways in the context of colonization and invasion with special emphasis on results from genome-wide surveys. The metabolism of lactate, the oxidative stress response, and, in particular, glutathione metabolism as well as the denitrification pathway provide examples of how meningococcal metabolism is intimately linked to pathogenesis. We further discuss evidence from genome-wide approaches regarding potential metabolic differences between strains from hyperinvasive and carriage lineages and present new data assessing in vitro growth differences of strains from these two populations. We hypothesize that strains from carriage and hyperinvasive lineages differ in the expression of regulatory genes involved particularly in stress responses and amino acid metabolism under infection conditions. KW - Neisseria meningitidis KW - virulence KW - pathometabolism KW - oxidative stress KW - glutathione KW - γ-glutamyl cycle KW - glutamate dehydrogenase KW - nitrite respiration Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-113118 ER - TY - JOUR A1 - Ruf, Dominik A1 - Brantl, Victor A1 - Wagener, Johannes T1 - Mitochondrial Fragmentation in \(Aspergillus\) \(fumigatus\) as Early Marker of Granulocyte Killing Activity JF - Frontiers in Cellular and Infection Microbiology N2 - The host's defense against invasive mold infections relies on diverse antimicrobial activities of innate immune cells. However, studying these mechanisms in vitro is complicated by the filamentous nature of such pathogens that typically form long, branched, multinucleated and compartmentalized hyphae. Here we describe a novel method that allows for the visualization and quantification of the antifungal killing activity exerted by human granulocytes against hyphae of the opportunistic pathogen Aspergillus fumigatus. The approach relies on the distinct impact of fungal cell death on the morphology of mitochondria that were visualized with green fluorescent protein (GFP). We show that oxidative stress induces complete fragmentation of the tubular mitochondrial network which correlates with cell death of affected hyphae. Live cell microscopy revealed a similar and non-reversible disruption of the mitochondrial morphology followed by fading of fluorescence in Aspergillus hyphae that were killed by human granulocytes. Quantitative microscopic analysis of fixed samples was subsequently used to estimate the antifungal activity. By utilizing this assay, we demonstrate that lipopolysaccharides as well as human serum significantly increase the killing efficacy of the granulocytes. Our results demonstrate that evaluation of the mitochondrial morphology can be utilized to assess the fungicidal activity of granulocytes against A. fumigatus hyphae. KW - Aspergillus fumigatus KW - killing KW - assay KW - PMNs KW - granulocytes KW - mitochondria KW - mitochondrial morphology KW - fungicidal activity Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-227133 VL - 8 IS - 128 ER - TY - THES A1 - Konrad, Christian T1 - Molecular analysis of insulin signaling mechanisms in Echinococcus multilocularis and their role in the host-parasite interaction in the alveolar echinococcosis T1 - Molekulare Analyse der Insulin-Signalmechanismen in Echinococcus multilocularis und ihre Rolle in der Wirt-Parasiten-Interaktion in der Alveolären Echinokokkose N2 - The insulin receptor ortholog EmIR of the fox-tapeworm Echinococcus multilocularis displays significant structural homology to the human insulin receptor (HIR) and has been suggested to be involved in insulin sensing mechanisms of the parasite’s metacestode larval stage. In the present work, the effects of host insulin on Echinococcus metacestode vesicles and the proposed interaction between EmIR and mammalian insulin have been studied using biochemical and cell-biological approaches. Human insulin, exogenously added to in vitro cultivated parasite larvae, (i) significantly stimulated parasite survival and growth, (ii) induced DNA de novo synthesis in Echinococcus, (iii) affected overall protein phosphorylation in the parasite, and (iv) specifically induced the phosphorylation of the parasite’s Erk-like MAP kinase orthologue EmMPK1. These results clearly indicated that Echinococcus metacestode vesicles are able to sense exogenous host insulin which induces a mitogenic response. To investigate whether EmIR mediates these effects, anti-EmIR antibodies were produced and utilized in biochemical assays and immunohistochemical analyses. EmIR was shown to be expressed in the germinal layer of the parasite both on the surface of glycogen storing cells and undifferentiated germinal cells. Upon addition of exogenous insulin to metacestode vesicles, the phosphorylation of EmIR was significantly induced, an effect which was suppressed in the presence of specific inhibitors of insulin receptor-like tyrosine kinases. Furthermore, upon expression of EmIR/HIR receptor chimera containing the extracellular ligand binding domain of EmIR in HEK 293 cells, a specific autophosphorylation of the chimera could be induced through the addition of exogenous insulin. These results indicated the capability of EmIR to sense and to transmit host insulin signals to the Echinococcus signaling machinery. The importance of insulin signaling mechanisms for parasite survival and growth were underscored by in vitro cultivation experiments in which the addition of an inhibitor of insulin receptor tyrosine kinases led to vesicle degradation and death. Based on the above outlined molecular data on the interaction between EmIR and mammalian insulin, the parasite’s insulin receptor orthologue most probably mediates the insulin effects on parasite growth and is, therefore, a potential candidate factor for host-parasite communication via evolutionary conserved pathways. In a final set of experiments, signaling mechanisms that act downstream of EmIR have been analyzed. These studies revealed significant differences between insulin signaling in Echinococcus and the related cestode parasite Taenia solium. These differences could be associated with differences in the organo-tropism of both species. N2 - Der orthologe Insulinrezeptor EmIR des Fuchsbandwurmes Echinococcus multilocularis weist signifikante strukturelle Homologie zum humanen Insulinrezeptor (HIR) auf. Es wurde schon seit geraumer Zeit vermutet, dass EmIR an den Mechanismen beteiligt sein könnte, die es dem Metacestoden Larvenstadium des Parasiten erlauben Insulin zu detektieren. In dieser Arbeit wurden die Effekte von Wirtsinsulin auf Echinococcus Metacestoden-Vesikel und die vermutete Interaktion zwischen EmIR und Insulin von Säugern mittels biochemischer und zellbiologischer experimenteller Ansätze untersucht. Die exogene Zugabe von humanem Insulin zu in vitro kultivierten Parasitenlarven hatte folgende Effekte: (i) das Überleben und das Wachstum des Parasiten wurde signifikant stimuliert; (ii) die DNA de novo Synthese in Echinococcus wurde induziert; (iii) die generelle Proteinphosphorylierung des Parasiten wurde beeinflusst; (iv) die Phosphorylierung der orthologen Erk-like MAP Kinase, EmMPK1, des Parasiten wurde spezifisch induziert. Diese Beobachtungen zeigen deutlich, dass Echinococcus Metacestoden-Vesikel exogenes Insulin des Wirtes detektieren können und dass dieses Insulin einen mitogenischen Effekt auf den Parasiten hat. Um zu untersuchen, ob diese Effekte durch EmIR vermittelt werden, wurden anti-EmIR Antikörper hergestellt und in biochemischen experimentellen Ansätzen und immunohistochemischen Analysen eingesetzt. Es konnte gezeigt werden, dass EmIR in der Germinalschicht des Parasiten expremiert wird, sowohl an der Oberfläche von Glykogen-Speicherzellen als auch von undifferenzierten Germinalzellen. Nach der Zugabe von exogenem Insulin konnte eine signifikante Zunahme der Phosphorylierung von EmIR festgestellt werden. Diese Stimulierung konnte durch die Zugabe eines spezifischen Inhibitors für Insulinrezeptor-ähnliche Tyrosinkinasen unterdrückt werden. Desweiteren konnte mittels der Expression eines chimären EmIR/HIR-Rezeptors, der die extrazelluläre Ligandenbindungsdomäne von EmIR enthielt, in HEK293 Zellen gezeigt werden, dass die Zugabe von exogenem Insulin eine spezifische Autophosphorylierung der Chimäre induziert. Diese Ergebnisse bezeugen die Fähigkeit von EmIR Insulin-abhängige Signale des Wirtes einerseits zu detektieren und andererseits an die Echinococcus Signalwege weiter zu leiten. Die Bedeutung von Insulin-Signalmechanismen für das Überleben und das Wachstum des Parasiten konnte durch in vitro Kultivierungsexperimente aufgezeigt werden. Die Zugabe eines Inhibitors spezifisch für Insulinrezeptor Tyrosinkinasen verursachte die Degradation und den Tod der Metacestoden-Vesikel. Basierend auf den dargelegten molekularen Daten bezüglich der Interaktion zwischen EmIR und Insulin von Säugern erscheint es sehr wahrscheinlich, dass der orthologe Insulinrezeptor des Parasiten die Effekte von Insulin auf das Wachstum des Parasiten vermittelt. Aus diesem Grund ist EmIR ein potentieller Kandidat für die Kommunikation zwischen Wirt und Parasiten mittels evolutionär konservierten Signalwegen. Die Signalmechanismen unterhalb von EmIR wurden in abschließenden Experimenten untersucht. Diese offenbarten deutliche Unterschiede in der Weiterleitung von Insulin induzierten Signalen zwischen Echinococcus und dem verwandten parasitären Zestoden Taenia solium. Diese Unterschiede könnten mit dem unterschiedlichen Organtropismus beider Arten in Verbindung stehen. KW - Fuchsbandwurm KW - Insulin KW - Echinokokkus KW - Insulin KW - Helminth KW - EmERK KW - Echinococcus KW - insulin KW - helminth KW - EmERK Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-22636 ER - TY - THES A1 - Koike, Akito T1 - Molekular und zellbiologischer Ansatz hin zu neuartigen Medikamenten gegen \(Echinococcus\) \(multilocularis\) T1 - Molecular and cell biological approach towards novel drugs against \(Echinococcus\) \(multilocularis\) N2 - Echinococcosis is an important zoonosis. The causative agent of Alveolar Echinococcosis (AE) is Echinococcus multilocularis. The treatment of human AE is limited to surgery and chemotherapy with albendazole (ABZ). However, ABZ works only parasitostatically and it needs to be taken for long periods, although it causes adverse side effects. Thus, development of new, parasiticidal drug with selective toxicity is required. Because undifferentiated stem cells of E. multilocularis play key role in its longevity and regenerative capacity, targeting stem cells is especially important. In vitro screening of protein kinases inhibitors demonstrated that human PIM kinases inhibitors have detrimental effects on E. multilocularis. Through yeast two hybrid assay, the interaction of parasite PIM kinase (EmPIM) and its CDC25 (EmCDC25) was indicated. Through in situ hybridization, expression of EmPIM in the stem cells was observed. Therefore, EmPim is likely to be a positive regulator of cell cycle progression, the same as human Pim1. In addition, 20 compounds against EmPIM were selected through in silico screening and synthesized. One of them has a detrimental effect on E.multilocularis comparable to human pan-PIM inhibitors, but has much weaker toxicity on human cell lines. Furthermore, triclabendazole (TCBZ) and its metabolite TCBZSX, which are approved for another flatworm disease, Fascioliasis were tried on E. multilocularis. With two stem cell markers, damage to stem cells by TCBZSX was shown. In addition, primary cells from treated vesicles never regenerated and the damage to stem cells proved to be irreversible. Our in silico screening method used in EmPIM research has potential to identify compounds which overcome the side effect problem in ABZ-based chemotherapy. On the other hand, it is expected that my research of TCBZ can lead to development of a practical parasiticidal chemotherapy by combining TCBZ, which damages stem cells, and ABZ, which damages differentiated cells. N2 - Die Echinokokkose ist eine der wichtigsten Zoonosen sowohl für die Human- als auch für die Veterinärmedizin. Der Erreger der alveolären Echinokokkose (AE) ist Echinococcus multilocularis. Metazestode Bläschen, das Larvenstadium dieses parasitären Helminthen, können in die Leber eindringen und ungeschlechtlich wie bösartige Tumore wachsen. Dies kann ohne geeignete Behandlung tödlich sein. Die Behandlung von AE beim Menschen beschränkt sich auf Chirurgie und Chemotherapie, aber die Chirurgie ist nur bei einem kleinen Prozentsatz der Patienten anwendbar, die im Frühstadium diagnostiziert werden. Die meisten Patienten können sich nur auf eine Chemotherapie mit Albendazol (ABZ) verlassen. ABZ wirkt jedoch nur parasitostatisch und kann die Krankheit nicht heilen. Daher muss ABZ über einen längeren Zeitraum eingenommen werden, obwohl es mit Nebenwirkungen einhergeht. Daher ist die Entwicklung eines neuen, parasitentötenden und selektiven Medikaments gegen AE erforderlich. Da die undifferenzierte Stammzellpopulation von E. multilocularis eine Schlüsselrolle für seine Langlebigkeit und Regenerationsfähigkeit spielt, ist eine auf Stammzellen abzielende Chemotherapie wichtig. In dieser Arbeit wurde ein In-vitro-Screening verschiedener Hemmstoffe gegen Kinasen und Tubuline durchgeführt. Das Ergebnis des Screenings zeigte, dass Inhibitoren gegen humane pim-Kinasen starke schädliche Auswirkungen auf E. multilocularis haben. Durch ein Hefe-Zwei- Hybrid-System wurde die Interaktion der Parasiten-Pim-Kinase (EmPIM) mit der Zellteilungszyklus 25 (EmCDC25) nachgewiesen, und durch In-situ-Hybridisierung wurde die teilweise Lokalisierung von EmPIM in den Stammzellen beobachtet. Daher ist es wahrscheinlich, dass EmPim ein positiver Regulator der Zellzyklusprogression ist, genau wie menschliches Pim1. ... KW - Bandwürmer KW - Zellzyklus KW - Benzimidazolderivate KW - tapeworm KW - kinase KW - benzimidazole Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-288649 ER - TY - THES A1 - Hemer, Sarah T1 - Molecular characterization of evolutionarily conserved signaling systems of Echinococcus multilocularis and their utilization for the development of novel drugs against Echinococosis T1 - Molekulare Charakterisierung evolutionsgeschichtlich konservierter Signalsysteme und deren Nutzung für die Entwicklung neuer Medikamente gegen Echinococcose N2 - Alveolar echinococcosis (AE), a severe and life-threatening disease is caused by the small fox tapeworm Echinococcus multilocularis. Currently, the options of chemotherapeutic treatment are very limited and are based on benzimidazole compounds, which act merely parasitostatic in vivo and often display strong side effects. Therefore, new therapeutic drugs and targets are urgently needed. In the present work the role of two evolutionarily conserved signalling pathways in E. multilocularis, namely the insulin signalling cascade and Abl kinases, has been studied in regard to host-parasite interaction and the possible use in anti-AE chemotherapy. N2 - Die alveoläre Echinokokkose ist eine ernste und lebensgefährliche Erkrankung, die durch den kleinen Fuchsbandwurm ausgelo ̈st wird. Die gegenwärtigen chemotherapeutischen Behandlungsmöglichkeiten beschränken sich auf die Behandlung mit Benzimidazolen, die in vivo nur parasitostatische Wirkung besitzen und häufig sehr starke Nebenwirkungen aufweisen. Aus diesem Grund besteht ein dringendes Bedürfnis nach neuen Medikamenten und Angriffszielen für diese. In der vorliegenden Arbeit wurde die Rolle zweier evolutionsgeschichtlich konservierter Signalsysteme, der Insulin Signalweg und die Abl Kinasen in E. multilocularis in Hinblick auf die Wirt-Parasiten Interaktion und dem mo ̈glichen Nutzen in der AE Chemotherapie untersucht. KW - Fuchsbandwurm KW - Insulin KW - Chemotherapie KW - Echinococcus KW - Insulin KW - Chemotherapie KW - Imatinib KW - Abl KW - Echinococcus KW - Insulin KW - Chemotherapy KW - Abl KW - Imatinib Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-74007 ER - TY - THES A1 - Herz, Michaela T1 - Molecular characterization of the serotonin and cAMP-signalling pathways in Echinococcus T1 - Molekulare Charakterisierung der Serotonin- und cAMP-Signalwege in Echinococcus N2 - Alveolar and cystic echinococcosis, caused by Echinococcus multilocularis and Echinococcus granulosus respectively, are severe zoonotic diseases with limited treatment options. The sole curative treatment is the surgical removal of the complete parasite material. Due to late diagnosis, chemotherapeutic treatment often is the only treatment option. Treatment is based on benzimidazoles, which merely act parasitostatic and often display strong side effects. Therefore, new therapeutic drugs are urgently needed. Evolutionarily conserved signalling pathways are known to be involved in hostparasite cross-communication, parasite development and survival. Moreover, they represent potential targets for chemotherapeutic drugs. In this context the roles of the serotonin- and cAMP-signalling pathways in Echinococcus were studied. Genes encoding serotonin receptors, a serotonin transporter and enzymes involved in serotonin biosynthesis could be identified in the E. multilocularis and E. granulosus genomes indicating that these parasites are capable of synthesizing and perceiving serotonin signals. Also the influence of exogenous serotonin on parasite development was studied. Serotonin significantly increased metacestode vesicle formation from primary cells and re-differentiation of protoscoleces. Inhibition of serotonin transport with citalopram significantly reduced metacestode vesicle formation from primary cells and caused death of protoscoleces and metacestodes. Furthermore, it could be shown that serotonin increased phosphorylation of protein kinase A substrates. Taken together, these results show that serotonin and serotonin transport are essential for Echinococcus development and survival. Consequently, components of the serotonin pathway represent potential drug targets. In this work the cAMP-signalling pathway was researched with focus on G-protein coupled receptors and adenylate cyclases. 76 G-protein coupled receptors, including members of all major families were identified in the E. multilocularis genome. Four genes homologous to adenylate cyclase IX were identified in the E. multilocularis genome and three in the E. granulosus genome. While glucagon caused no significant effects, the adenylate cyclase activator forskolin and the adenylate cyclase inhibitor 2’, 5’ didesoxyadenosine influenced metacestode vesicle formation from primary cells, re-differentiation of protoscoleces and survival of metacestodes. It was further shown that forskolin increases phosphorylation of protein kinase A substrates, indicating that forskolin activates the cAMP-pathway also in cestodes. These results indicate that the cAMP signalling pathway plays an important role in Echinococcus development and survival. To complement this work, the influence of different media and additives on E. granulosus protoscoleces was investigated. Anaerobic conditions and the presence of FBS prolonged protoscolex survival while different media influenced protoscolex activation and development. Taken together, this work provided important insights into developmental processes in Echinococcus and potential drug targets for echinococcosis chemotherapy. N2 - Alveoläre und zystische Echinokokkose, hervorgerufen durch Echinococcus multilocularis und Echinococcus granulosus, sind schwere zoonotische Erkrankungen mit eingeschränkten Behandlungsmöglichkeiten. Die einzig kurative Therapie besteht in der chirurgischen Entfernung des gesammten Parasitenmaterials. Aufgrund später Diagnosestellung stellt Chemotherapie oft die einzige Behandlungsmöglichkeit dar. Die derzeitige Therapie basiert auf Benzimidazolen, welche nur parasitostatisch wirken und oft schwere Nebenwirkungen hervorrufen. Neue Medikamente werden daher dringend benötigt. Evolutionär konservierte Signalwege sind bekanntermaßen an Wirt-Parasit Kreuzkommunikation, Parasitenentwicklung und deren Überleben beteiligt. Darüber hinaus stellen sie auch mögliche Angriffspunkte für Chemotherapeutika dar. In diesem Zusammenhang wurden die Rollen des Serotonin- und des cAMP-Signalwegs in Echinococcus untersucht. Gene für Serotoninrezeptoren, einen Serotonintransporter und für Enzyme, die in der Serotoninsynthese involviert sind, konnten in den E. multilocularis und E. granulosus Genomen identifiziert werden, was darauf schließen lässt, dass diese Parasiten in der Lage sind, Serotonin selbst herzustellen und zu sensieren. Des Weiteren wurde der Einfluss von exogenem Serotonin auf die Parasitenentwicklung untersucht. Serotonin förderte die Bildung von Metazestodenvesikeln aus Primärzellen und die Rückdifferenzierung von Protoskolizes signifikant. Die Hemmung des Serotonintransports mit Citalopram reduzierte die Bildung von Metazestodenvesikeln aus Primärzellen signifikant und führte zum Absterben von Protoskolizes undMetazestoden. Des Weiteren konnte gezeigt werden, dass Serotonin die Posphorylierung von Proteinkinase A Substraten erhöht. Zusammengefasst zeigen diese Ergebnisse, dass Serotonin und Serotonintransport essentiell f¨ur die Entwicklung und das Überleben von Echinococcus sind. Folglich stellen Komponenten des Serotoninsignalwegs potentielle Angriffspunkte für Medikamente dar. In dieser Arbeit wurde der cAMP-Signalweg mit Schwerpunkt auf G-Protein gekoppelte Rezeptoren und Adenylatzyklasen untersucht. 76 G-Protein gekoppelte Rezeptoren, inclusive Mitglieder aller Hauptfamilien, wurden im E. multilocularis-Genom identifiziert. Vier Homologe zur Adenylatzyklase IX wurden im E. multilocularis- Genom und drei im E. granulosus-Genom identifiziert. Während Glukagon keine signifikanten Effekte hervorrief, beeinflussten der Adenylatzyklase-Aktivator Forskolin und der Adenylatzyklase-Inhibitor 2’, 5’-Didesoxyadenosin die Bildung von Metazestodenvesikeln aus Primärzellen, die Rückdifferenzierung von Protoskolizes und das Überleben vonMetazestoden. Zudem wurde gezeigt, dass Forskolin die Phosphorylierung von Proteinkinase A-Substraten erhöht. Dies bestätigt, dass Forskolin den cAMP-Signalweg aktiviert. Diese Ergebnisse legen nahe, dass der cAMP-Signalweg eine wichtige Rolle in der Entwicklung und dem Überleben von Echinococcus spielt. Um diese Arbeit zu vervollständigen, wurde der Einfluss von verschiedenen Medien und Zusätzen auf E. granulosus Protoskolizes untersucht. Anaerobe Bedingungen und die Anwesenheit von FBS verlängerten das Überleben von Protoskolizes, während verschiedene Medien die Aktivierung und die Entwicklung von Protoskolizes beeinflussten. Insgesamt gibt diese Arbeit wichtige Einblicke in Entwicklungsprozesse von Echinococcus und zeigt potentielle Angriffspunkte für Medikamente auf. KW - Serotonin KW - Cyclo-AMP KW - Fuchsbandwurm KW - cAMP KW - Echinococcus Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-139249 ER - TY - JOUR A1 - Zoran, Tamara A1 - Seelbinder, Bastian A1 - White, Philip Lewis A1 - Price, Jessica Sarah A1 - Kraus, Sabrina A1 - Kurzai, Oliver A1 - Linde, Joerg A1 - Häder, Antje A1 - Loeffler, Claudia A1 - Grigoleit, Goetz Ulrich A1 - Einsele, Hermann A1 - Panagiotou, Gianni A1 - Loeffler, Juergen A1 - Schäuble, Sascha T1 - Molecular profiling reveals characteristic and decisive signatures in patients after allogeneic stem cell transplantation suffering from invasive pulmonary aspergillosis JF - Journal of Fungi N2 - Despite available diagnostic tests and recent advances, diagnosis of pulmonary invasive aspergillosis (IPA) remains challenging. We performed a longitudinal case-control pilot study to identify host-specific, novel, and immune-relevant molecular candidates indicating IPA in patients post allogeneic stem cell transplantation (alloSCT). Supported by differential gene expression analysis of six relevant in vitro studies, we conducted RNA sequencing of three alloSCT patients categorized as probable IPA cases and their matched controls without Aspergillus infection (66 samples in total). We additionally performed immunoassay analysis for all patient samples to gain a multi-omics perspective. Profiling analysis suggested LGALS2, MMP1, IL-8, and caspase-3 as potential host molecular candidates indicating IPA in investigated alloSCT patients. MMP1, IL-8, and caspase-3 were evaluated further in alloSCT patients for their potential to differentiate possible IPA cases and patients suffering from COVID-19-associated pulmonary aspergillosis (CAPA) and appropriate control patients. Possible IPA cases showed differences in IL-8 and caspase-3 serum levels compared with matched controls. Furthermore, we observed significant differences in IL-8 and caspase-3 levels among CAPA patients compared with control patients. With our conceptual work, we demonstrate the potential value of considering the human immune response during Aspergillus infection to identify immune-relevant molecular candidates indicating IPA in alloSCT patients. These human host candidates together with already established fungal biomarkers might improve the accuracy of IPA diagnostic tools. KW - host response KW - invasive pulmonary aspergillosis KW - alloSCT patients KW - galectin-2 KW - caspase-3 KW - matrix metallopeptidase-1 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-262105 SN - 2309-608X VL - 8 IS - 2 ER - TY - JOUR A1 - Silwedel, Christine A1 - Haarmann, Axel A1 - Fehrholz, Markus A1 - Claus, Heike A1 - Speer, Christian P. A1 - Glaser, Kirsten T1 - More than just inflammation: Ureaplasma species induce apoptosis in human brain microvascular endothelial cells JF - Journal of Neuroinflammation N2 - Background Ureaplasma species (spp.) are commonly regarded as low-virulent commensals but may cause invasive diseases in immunocompromised adults and in neonates, including neonatal meningitis. The interactions of Ureaplasma spp. with host defense mechanisms are poorly understood. This study addressed Ureaplasma-driven cell death, concentrating on apoptosis as well as inflammatory cell death. Methods Human brain microvascular endothelial cells (HBMEC) were exposed to Ureaplasma (U.) urealyticum serovar 8 (Uu8) and U. parvum serovar 3 (Up3). Resulting numbers of dead cells as well as mRNA levels and enzyme activity of key agents in programmed cell death were assessed by flow cytometry, RNA sequencing, and qRT-PCR, respectively. xCELLigence data were used for real-time monitoring of changes in cell adhesion properties. Results Both Ureaplasma isolates induced cell death (p < 0.05, vs. broth). Furthermore, Ureaplasma spp. enhanced mRNA levels for genes in apoptosis, including caspase 3 (Up3 p < 0.05, vs. broth), caspase 7 (p < 0.01), and caspase 9 (Up3 p < 0.01). Caspase 3 activity was increased upon Uu8 exposure (p < 0.01). Vice versa, Ureaplasma isolates downregulated mRNA levels for proteins involved in inflammatory cell death, namely caspase 1 (Uu8 p < 0.01, Up3 p < 0.001), caspase 4 (Uu8 p < 0.05, Up3 p < 0.01), NOD-like receptor pyrin domain-containing 3 (Uu8 p < 0.05), and receptor-interacting protein kinase 3 (p < 0.05). Conclusions By inducing apoptosis in HBMEC as main constituents of the blood-brain barrier, Ureaplasma spp. may provoke barrier breakdown. Simultaneous suppression of inflammatory cell death may additionally attenuate host defense strategies. Ultimate consequence could be invasive and long-term CNS infections by Ureaplasma spp. KW - Ureaplasma urealyticum KW - Ureaplasma parvum KW - Neuroinflammation KW - Meningitis KW - Caspase KW - Apoptosis KW - HBMEC Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-200711 VL - 16 ER - TY - JOUR A1 - Schubert-Unkmeir, Alexandra A1 - Konrad, Christian A1 - Slanina, Heiko A1 - Czapek, Florian A1 - Hebling, Sabrina A1 - Frosch, Matthias T1 - Neisseria meningitidis Induces Brain Microvascular Endothelial Cell Detachment from the Matrix and Cleavage of Occludin: A Role for MMP-8 N2 - Disruption of the blood-brain barrier (BBB) is a hallmark event in the pathophysiology of bacterial meningitis. Several inflammatory mediators, such as tumor necrosis factor alpha (TNF-a), nitric oxide and matrix metalloproteinases (MMPs), contribute to this disruption. Here we show that infection of human brain microvascular endothelial cells (HBMEC) with Neisseria meningitidis induced an increase of permeability at prolonged time of infection. This was paralleled by an increase in MMP-8 activity in supernatants collected from infected cells. A detailed analysis revealed that MMP-8 was involved in the proteolytic cleavage of the tight junction protein occludin, resulting in its disappearance from the cell periphery and cleavage to a lower-sized 50-kDa protein in infected HBMEC. Abrogation of MMP-8 activity by specific inhibitors as well as transfection with MMP-8 siRNA abolished production of the cleavage fragment and occludin remained attached to the cell periphery. In addition, MMP-8 affected cell adherence to the underlying matrix. A similar temporal relationship was observed for MMP activity and cell detachment. Injury of the HBMEC monolayer suggested the requirement of direct cell contact because no detachment was observed when bacteria were placed above a transwell membrane or when bacterial supernatant was directly added to cells. Inhibition of MMP-8 partially prevented detachment of infected HBMEC and restored BBB permeability. Together, we established that MMP-8 activity plays a crucial role in disassembly of cell junction components and cell adhesion during meningococcal infection. KW - Neisseria meningitidis Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-68589 ER - TY - JOUR A1 - Silwedel, Christine A1 - Speer, Christian P. A1 - Haarmann, Axel A1 - Fehrholz, Markus A1 - Claus, Heike A1 - Buttmann, Mathias A1 - Glaser, Kirsten T1 - Novel insights into neuroinflammation: bacterial lipopolysaccharide, tumor necrosis factor α, and Ureaplasma species differentially modulate atypical chemokine receptor 3 responses in human brain microvascular endothelial cells JF - Journal of Neuroinflammation N2 - Background: Atypical chemokine receptor 3 (ACKR3, synonym CXCR7) is increasingly considered relevant in neuroinflammatory conditions, in which its upregulation contributes to compromised endothelial barrier function and may ultimately allow inflammatory brain injury. While an impact of ACKR3 has been recognized in several neurological autoimmune diseases, neuroinflammation may also result from infectious agents, including Ureaplasma species (spp.). Although commonly regarded as commensals of the adult urogenital tract, Ureaplasma spp. may cause invasive infections in immunocompromised adults as well as in neonates and appear to be relevant pathogens in neonatal meningitis. Nonetheless, clinical and in vitro data on Ureaplasma-induced inflammation are scarce. Methods: We established a cell culture model of Ureaplasma meningitis, aiming to analyze ACKR3 variances as a possible pathomechanism in Ureaplasma-associated neuroinflammation. Non-immortalized human brain microvascular endothelial cells (HBMEC) were exposed to bacterial lipopolysaccharide (LPS) or tumor necrosis factor-α (TNF-α), and native as well as LPS-primed HBMEC were cultured with Ureaplasma urealyticum serovar 8 (Uu8) and U. parvum serovar 3 (Up3). ACKR3 responses were assessed via qRT-PCR, RNA sequencing, flow cytometry, and immunocytochemistry. Results: LPS, TNF-α, and Ureaplasma spp. influenced ACKR3 expression in HBMEC. LPS and TNF-α significantly induced ACKR3 mRNA expression (p < 0.001, vs. control), whereas Ureaplasma spp. enhanced ACKR3 protein expression in HBMEC (p < 0.01, vs. broth control). Co-stimulation with LPS and either Ureaplasma isolate intensified ACKR3 responses (p < 0.05, vs. LPS). Furthermore, stimulation wielded a differential influence on the receptor’s ligands. Conclusions: We introduce an in vitro model of Ureaplasma meningitis. We are able to demonstrate a pro-inflammatory capacity of Ureaplasma spp. in native and, even more so, in LPS-primed HBMEC, underlining their clinical relevance particularly in a setting of co-infection. Furthermore, our data may indicate a novel role for ACKR3, with an impact not limited to auto-inflammatory diseases, but extending to infection-related neuroinflammation as well. AKCR3-induced blood-brain barrier breakdown might constitute a potential common pathomechanism. KW - atypical chemokine receptor 3 KW - human brain microvascular endothelial cells KW - meningitis KW - neuroinflammation KW - Ureaplasma species Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-175952 VL - 15 IS - 156 ER - TY - JOUR A1 - Brehm, Klaus A1 - Koziol, Uriel T1 - On the importance of targeting parasite stem cells in anti-echinococcosis drug development T1 - De l’importance de cibler les cellules souches du parasite dans la recherche de nouveaux médicaments contre les échinococcoses JF - Parasite N2 - The life-threatening diseases alveolar and cystic echinococcoses are caused by larvae of the tapeworms Echinococcus multilocularis and E. granulosus, respectively. In both cases, intermediate hosts, such as humans, are infected by oral uptake of oncosphere larvae, followed by asexual multiplication and almost unrestricted growth of the metacestode within host organs. Besides surgery, echinococcosis treatment relies on benzimidazole-based chemotherapy, directed against parasite beta-tubulin. However, since beta-tubulins are highly similar between cestodes and humans, benzimidazoles can only be applied at parasitostatic doses and are associated with adverse side effects. Mostly aiming at identifying alternative drug targets, the nuclear genome sequences of E. multilocularis and E. granulosus have recently been characterized, revealing a large number of druggable targets that are expressed by the metacestode. Furthermore, recent cell biological investigations have demonstrated that E. multilocularis employs pluripotent stem cells, called germinative cells, which are the only parasite cells capable of proliferation and which give rise to all differentiated cells. Hence, the germinative cells are the crucial cell type mediating proliferation of E. multilocularis, and most likely also E. granulosus, within host organs and should also be responsible for parasite recurrence upon discontinuation of chemotherapy. Interestingly, recent investigations have also indicated that germinative cells might be less sensitive to chemotherapy because they express a beta-tubulin isoform with limited affinity to benzimidazoles. In this article, we briefly review the recent findings concerning Echinococcus genomics and stem cell research and propose that future research into anti-echinococcosis drugs should also focus on the parasite’s stem cell population. N2 - Les échinococcoses alvéolaire et kystique, deux maladies potentiellement mortelles, sont respectivement causées par les larves des vers plats Echinococcus multilocularis et E. granulosus. Dans les deux cas, les hôtes intermédiaires, comme l’homme, s’infectent par l’ingestion des oncosphères, suivie de la multiplication asexuée et la croissance presque illimitée du métacestode dans les organes de l’hôte. À côté de la chirurgie, le traitement des échinococcoses repose sur une chimiothérapie par les benzimidazoles, dont l’action est dirigée contre la bêta-tubuline du parasite. Cependant, comme les bêta-tubulines sont extrêmement similaires chez les cestodes et les humains, les benzimidazoles ne peuvent être utilisés qu’à des posologies parasitostatiques et sont associés à des effets secondaires indésirables. Avec l’objectif principal d’identifier des cibles pour des médicaments alternatifs, le génome nucléaire d’E. multilocularis et d’E. granulosus a été récemment séquencé, et de nombreuses cibles potentielles pour des médicaments sont exprimées par le métacestode. De plus, des études récentes de biologie cellulaire ont montré qu’E. multilocularis dispose de cellules souches multipotentes, appelées cellules germinales, qui sont les seules cellules parasitaires capables de prolifération et à l’origine de toutes les cellules différenciées. Ces cellules germinales représentent donc un type cellulaire crucial pour la prolifération d’E. multilocularis, et très vraisemblablement aussi d’E. granulosus, dans les organes de l’hôte, et vraisemblablement responsables des récurrences parasitaires à l’arrêt de la chimiothérapie. Des études récentes ont aussi indiqué que les cellules germinales pourraient être moins sensibles à la chimiothérapie car elles expriment un isoforme de la bêta-tubuline à affinité limitée vis-à-vis des benzimidazoles. Dans cet article, nous faisons une courte revue des découvertes récentes concernant la génomique d’Echinococcus et la recherche sur les cellules souches. Nous proposons que les recherches futures sur de nouveaux médicaments contre les échinococcoses se focalisent sur la population des cellules souches du parasite. KW - genome KW - chemotherapy KW - benzimidazole KW - stem cells KW - germinative cells KW - beta-tubulin Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-118030 SN - 1252-607X VL - 21 ER - TY - JOUR A1 - Hubert, Kerstin A1 - Pawlik, Marie-Christin A1 - Claus, Heike A1 - Jarva, Hanna A1 - Meri, Seppo A1 - Vogel, Ulrich T1 - Opc Expression, LPS Immunotype Switch and Pilin Conversion Contribute to Serum Resistance of Unencapsulated Meningococci JF - PLoS One N2 - Neisseria meningitidis employs polysaccharides and outer membrane proteins to cope with human serum complement attack. To screen for factors influencing serum resistance, an assay was developed based on a colorimetric serum bactericidal assay. The screening used a genetically modified sequence type (ST)-41/44 clonal complex (cc) strain lacking LPS sialylation, polysaccharide capsule, the factor H binding protein (fHbp) and MutS, a protein of the DNA repair mechanism. After killing of >99.9% of the bacterial cells by serum treatment, the colorimetric assay was used to screen 1000 colonies, of which 35 showed enhanced serum resistance. Three mutant classes were identified. In the first class of mutants, enhanced expression of Opc was identified. Opc expression was associated with vitronectin binding and reduced membrane attack complex deposition confirming recent observations. Lipopolysaccharide (LPS) immunotype switch from immunotype L3 to L8/L1 by lgtA and lgtC phase variation represented the second class. Isogenic mutant analysis demonstrated that in ST-41/44 cc strains the L8/L1 immunotype was more serum resistant than the L3 immunotype. Consecutive analysis revealed that the immunotypes L8 and L1 were frequently observed in ST-41/44 cc isolates from both carriage and disease. Immunotype switch to L8/L1 is therefore suggested to contribute to the adaptive capacity of this meningococcal lineage. The third mutant class displayed a pilE allelic exchange associated with enhanced autoaggregation. The mutation of the C terminal hypervariable region D of PilE included a residue previously associated with increased pilus bundle formation. We suggest that autoaggregation reduced the surface area accessible to serum complement and protected from killing. The study highlights the ability of meningococci to adapt to environmental stress by phase variation and intrachromosomal recombination affecting subcapsular antigens. KW - factor H KW - C-reactive protein KW - B neisseria meningitidis KW - outer membrane protein KW - phase variation KW - serogroup B KW - bactericidal activity KW - epithelial cells KW - gene conversion KW - strain MC58 Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-135421 VL - 7 IS - 9 ER - TY - JOUR A1 - Kim, Brandon J. A1 - Shusta, Eric V. A1 - Doran, Kelly S. T1 - Past and current perspectives in modeling bacteria and blood–brain barrier interactions JF - Frontiers in Microbiology N2 - The central nervous system (CNS) barriers are highly specialized cellular barriers that promote brain homeostasis while restricting pathogen and toxin entry. The primary cellular constituent regulating pathogen entry in most of these brain barriers is the brain endothelial cell (BEC) that exhibits properties that allow for tight regulation of CNS entry. Bacterial meningoencephalitis is a serious infection of the CNS and occurs when bacteria can cross specialized brain barriers and cause inflammation. Models have been developed to understand the bacterial – BEC interaction that lead to pathogen crossing into the CNS, however, these have been met with challenges due to these highly specialized BEC phenotypes. This perspective provides a brief overview and outlook of the in vivo and in vitro models currently being used to study bacterial brain penetration, and opinion on improved models for the future. KW - bacteria KW - blood–brain barrier KW - meningitis KW - stem cells KW - brain endothelial cell Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-201766 VL - 10 IS - 1336 ER - TY - JOUR A1 - Häder, Antje A1 - Schäuble, Sascha A1 - Gehlen, Jan A1 - Thielemann, Nadja A1 - Buerfent, Benedikt C. A1 - Schüller, Vitalia A1 - Hess, Timo A1 - Wolf, Thomas A1 - Schröder, Julia A1 - Weber, Michael A1 - Hünniger, Kerstin A1 - Löffler, Jürgen A1 - Vylkova, Slavena A1 - Panagiotou, Gianni A1 - Schumacher, Johannes A1 - Kurzai, Oliver T1 - Pathogen-specific innate immune response patterns are distinctly affected by genetic diversity JF - Nature Communications N2 - Innate immune responses vary by pathogen and host genetics. We analyze quantitative trait loci (eQTLs) and transcriptomes of monocytes from 215 individuals stimulated by fungal, Gram-negative or Gram-positive bacterial pathogens. We identify conserved monocyte responses to bacterial pathogens and a distinct antifungal response. These include 745 response eQTLs (reQTLs) and corresponding genes with pathogen-specific effects, which we find first in samples of male donors and subsequently confirm for selected reQTLs in females. reQTLs affect predominantly upregulated genes that regulate immune response via e.g., NOD-like, C-type lectin, Toll-like and complement receptor-signaling pathways. Hence, reQTLs provide a functional explanation for individual differences in innate response patterns. Our identified reQTLs are also associated with cancer, autoimmunity, inflammatory and infectious diseases as shown by external genome-wide association studies. Thus, reQTLs help to explain interindividual variation in immune response to infection and provide candidate genes for variants associated with a range of diseases. KW - antimicrobial responses KW - immunogenetics Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-357441 VL - 14 ER - TY - JOUR A1 - Krüger, Sören A1 - Leskien, Miriam A1 - Schuller, Patricia A1 - Prifert, Christiane A1 - Weißbrich, Benedikt A1 - Vogel, Ulrich A1 - Krone, Manuel T1 - Performance and feasibility of universal PCR admission screening for SARS‐CoV‐2 in a German tertiary care hospital JF - Journal of Medical Virology N2 - Anamnestic screening of symptoms and contact history is applied to identify coronavirus disease 2019 (COVID‐19) patients on admission. However, asymptomatic and presymptomatic patients remain undetected although the viral load may be high. In this retrospective cohort study, all hospitalized patients who received polymerase chain reaction (PCR) admission testing from March 26th until May 24th, 2020 were included. Data on COVID‐19‐specific symptoms and contact history to COVID‐19 cases were retrospectively extracted from patient files and from contact tracing notes. The compliance to the universal testing protocol was high with 90%. Out of 6940 tested patients, 27 new severe acute respiratory syndrome coronavirus‐2 infections (0.4%) were detected. Seven of those COVID‐19 cases (26% of all new cases) were asymptomatic and had no positive contact history, but were identified through a positive PCR test. The number needed to identify an asymptomatic patient was 425 in the first wave of the epidemic, 1218 in the low incidence phase. The specificity of the method was above 99.9%. Universal PCR testing was highly accepted by staff as demonstrated by high compliance. The costs to detect one asymptomatic case in future studies need to be traded off against the costs and damage caused by potential outbreaks of COVID‐19. KW - admission screening KW - COVID‐19 KW - infection control KW - SARS‐CoV‐2 KW - testing strategy Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-238971 VL - 93 IS - 5 SP - 2890 EP - 2898 ER - TY - JOUR A1 - Elias, Johannes A1 - Findlow, Jamie A1 - Borrow, Ray A1 - Tremmel, Angelika A1 - Frosch, Matthias A1 - Vogel, Ulrich T1 - Persistence of antibodies in laboratory staff immunized with quadrivalent meningococcal polysaccharide vaccine JF - Journal of Occupational Medicine and Toxicology N2 - Background Occupational exposure to live meningococci can potentially cause invasive meningococcal disease in laboratory staff. While, until recently, immunization with quadrivalent polysaccharide vaccine represented one cornerstone of protection, data on long-term persistence of antibodies in adults remain scarce. Methods We analyzed the relationship of antibody levels and time following quadrivalent polysaccharide vaccination (Mencevax® ACWY, GlaxoSmithKline) in a cross-sectional sample of 20 laboratory workers vaccinated at ages between 16.4 to 40.7 years from Germany. Sera were obtained 0.4 to 158.5 (median 35.3) months after vaccination. At the time of sampling, laboratory workers had been regularly exposed to meningococci for periods between 3.2 to 163.8 (median 41.2) months. Serum bactericidal assay (SBA) with rabbit complement and a microsphere-based flow analysis method were used to determine bactericidal titers and concentrations of IgG, respectively, against serogroups A, C, W135, and Y. Decay of antibodies was modeled using linear regression. Protective levels were defined as SBA titers ≥ 8. Results Half-lives of SBA titers against serogroups A, C, W135, and Y were estimated at 27.4, 21.9, 18.8, and 28.0 months, respectively. Average durations of protection were estimated at 183.9, 182.0, 114.6, and 216.4 months, respectively. Inter-individual variation was high; using lower margins of 95% prediction intervals, minimal durations of protection against serogroups A, C, W135 and Y were estimated at 33.5, 24.6, 0.0, and 55.1 months, respectively. The proportion of staff with protective SBA titers against W135 (65.0%) was significantly lower than proportions protected against A (95.0%), C (94.7%), and Y (95.0%). Consistently, geometric mean titer (97.0) and geometric mean concentration of IgG (2.1 μg/ml) was lowest against serogroup W135. SBA titers in a subset of individuals with incomplete protection rose to ≥ 128 (≥ 8 fold) after reimmunization with a quadrivalent glycoconjugate vaccine. Conclusions The average duration of protection following immunization with a quadrivalent polysaccharide vaccine in adults was ≥ 115 months regardless of serogroup. A substantial proportion (approximately 23% according to our decay model) of adult vaccinees may not retain protection against serogroup W135 for five years, the time suggested for reimmunization. KW - Vaccination KW - Meningococcal infection KW - Biohazard KW - Meningococcal polysaccharide caccine Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-95953 UR - http://www.occup-med.com/content/8/1/4 ER - TY - JOUR A1 - Schwerk, Christian A1 - Papandreou, Thalia A1 - Schuhmann, Daniel A1 - Nickol, Laura A1 - Borkowski, Julia A1 - Steinmann, Ulrike A1 - Quednau, Natascha A1 - Stump, Carolin A1 - Weiss, Christel A1 - Berger, Jürgen A1 - Wolburg, Hartwig A1 - Claus, Heike A1 - Vogel, Ulrich A1 - Ishikawa, Hiroshi A1 - Tenenbaum, Tobias A1 - Schroten, Horst T1 - Polar Invasion and Translocation of Neisseria meningitidis and Streptococcus suis in a Novel Human Model of the Blood-Cerebrospinal Fluid Barrier JF - PLoS One N2 - Acute bacterial meningitis is a life-threatening disease in humans. Discussed as entry sites for pathogens into the brain are the blood-brain and the blood-cerebrospinal fluid barrier (BCSFB). Although human brain microvascular endothelial cells (HBMEC) constitute a well established human in vitro model for the blood-brain barrier, until now no reliable human system presenting the BCSFB has been developed. Here, we describe for the first time a functional human BCSFB model based on human choroid plexus papilloma cells (HIBCPP), which display typical hallmarks of a BCSFB as the expression of junctional proteins and formation of tight junctions, a high electrical resistance and minimal levels of macromolecular flux when grown on transwell filters. Importantly, when challenged with the zoonotic pathogen Streptococcus suis or the human pathogenic bacterium Neisseria meningitidis the HIBCPP show polar bacterial invasion only from the physiologically relevant basolateral side. Meningococcal invasion is attenuated by the presence of a capsule and translocated N. meningitidis form microcolonies on the apical side of HIBCPP opposite of sites of entry. As a functionally relevant human model of the BCSFB the HIBCPP offer a wide range of options for analysis of disease-related mechanisms at the choroid plexus epithelium, especially involving human pathogens. KW - gene expression KW - plexus epithelial-cells KW - central-nervous-system KW - microvascular endothelial-cells KW - choroid-plexus KW - in vitro KW - brain barrier KW - tight junctions KW - meningococcal disease KW - bacterial meningitis Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-131459 VL - 7 IS - 1 ER - TY - JOUR A1 - Dick, Julia A1 - Krauß, Patrizia A1 - Hillenkamp, Jost A1 - Kohlmorgen, Britta A1 - Schoen, Christoph T1 - Postoperative Tropheryma whipplei endophthalmitis – a case report highlighting the additive value of molecular testing JF - JMM Case Reports N2 - Introduction. Tropheryma whipplei is the causative agent of Whipple’s disease. Gastrointestinal and lymphatic tissues are affected in the majority of cases, resulting in diarrhoea, malabsorption and fever. Here, we report a rare case of ocular manifestation in a patient lacking the typical Whipple symptoms. Case presentation. A 74-year-old Caucasian female presented with blurred vision in the right eye over a period of 1–2 months, accompanied by stinging pain and conjunctival hyperaemia for the last 2 days. Upon admission, visual acuity was hand motion in the affected eye. Ophthalmological examination showed typical signs of intraocular inflammation. Diagnostic and therapeutic pars plana vitrectomy including vitreous biopsy and intravitreal instillation of vancomycin and amikacin was performed within hours of initial presentation. Both microscopic analysis and microbial cultures of the vitreous biopsy remained negative for bacteria and fungi. The postoperative antibiotic regime included intravenous administration of ceftriaxone in combination with topical tobramycin and ofloxacin. Due to the empirical therapy the inflammation ceased and the patient was discharged after 5 days with cefpodoxime orally and local antibiotic and steroidal therapy. Meanwhile, the vitreous body had undergone testing by PCR for the eubacterial 16S rRNA gene, which was found to be positive. Analysis of the PCR product revealed a specific sequence of T. whipplei. Conclusion. In our patient, endophthalmitis was the first and only symptom of Morbus Whipple, while most patients with Whipple’s disease suffer from severe gastrointestinal symptoms. 16S rDNA PCR should be considered for any intraocular infection when microscopy and standard culture methods remain negative. KW - intravitreal vancomycin and amikacin KW - intravenous ceftriaxone KW - topic ofloxacin KW - Whipple's disease KW - endophthalmitis KW - Tropheryma whipplei KW - ocular infection KW - vitrectomy KW - oral cefpodoxime KW - oral doxycycline Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-158823 VL - 4 ER - TY - JOUR A1 - Prauße, Maria T. E. A1 - Lehnert, Teresa A1 - Timme, Sandra A1 - Hünniger, Kerstin A1 - Leonhardt, Ines A1 - Kurzai, Oliver A1 - Figge, Marc Thilo T1 - Predictive Virtual Infection Modeling of Fungal Immune Evasion in Human Whole Blood JF - Frontiers in Immunology N2 - Bloodstream infections by the human-pathogenic fungi Candida albicans and Candida glabrata increasingly occur in hospitalized patients and are associated with high mortality rates. The early immune response against these fungi in human blood comprises a concerted action of humoral and cellular components of the innate immune system. Upon entering the blood, the majority of fungal cells will be eliminated by innate immune cells, i.e., neutrophils and monocytes. However, recent studies identified a population of fungal cells that can evade the immune response and thereby may disseminate and cause organ dissemination, which is frequently observed during candidemia. In this study, we investigate the so far unresolved mechanism of fungal immune evasion in human whole blood by testing hypotheses with the help of mathematical modeling. We use a previously established state-based virtual infection model for whole-blood infection with C. albicans to quantify the immune response and identified the fungal immune-evasion mechanism. While this process was assumed to be spontaneous in the previous model, we now hypothesize that the immune-evasion process is mediated by host factors and incorporate such a mechanism in the model. In particular, we propose, based on previous studies that the fungal immune-evasion mechanism could possibly arise through modification of the fungal surface by as of yet unknown proteins that are assumed to be secreted by activated neutrophils. To validate or reject any of the immune-evasion mechanisms, we compared the simulation of both immune-evasion models for different infection scenarios, i.e., infection of whole blood with either C. albicans or C. glabrata under non-neutropenic and neutropenic conditions. We found that under non-neutropenic conditions, both immune-evasion models fit the experimental data from whole-blood infection with C. albicans and C. glabrata. However, differences between the immune-evasion models could be observed for the infection outcome under neutropenic conditions with respect to the distribution of fungal cells across the immune cells. Based on these predictions, we suggested specific experimental studies that might allow for the validation or rejection of the proposed immune-evasion mechanism. KW - immune evasion KW - state-based model KW - innate immune response KW - polymorphonuclear neutrophils KW - whole-blood infection assay Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-197493 SN - 1664-3224 VL - 9 IS - 560 ER -