27 research outputs found

    A novel TMPRSS6 mutation that prevents protease auto-activation causes IRIDA

    Get PDF
    IRIDA (iron-refractory iron-deficiency anaemia) is a rare autosomal-recessive disorder hallmarked by hypochromic microcytic anaemia, low transferrin saturation and high levels of the iron-regulated hormone hepcidin. The disease is caused by mutations in the transmembrane serine protease TMPRSS6 (transmembrane protease serine 6) that prevent inactivation of HJV (haemojuvelin), an activator of hepcidin transcription. In the present paper, we describe a patient with IRIDA who carries a novel mutation (Y141C) in the SEA domain of the TMPRSS6 gene. Functional characterization of the TMPRSS6(Y141C) mutant protein in cultured cells showed that it localizes to similar subcellular compartments as wild-type TMPRSS6 and binds HJV, but fails to auto-catalytically activate itself. As a consequence, hepcidin mRNA expression is increased, causing the clinical symptoms observed in this IRIDA patient. The present study provides important mechanistic insight into how TMPRSS6 is activated

    Tumor-derived GDF-15 blocks LFA-1 dependent T cell recruitment and suppresses responses to anti-PD-1 treatment

    Get PDF
    Immune checkpoint blockade therapy is beneficial and even curative for some cancer patients. However, the majority don't respond to immune therapy. Across different tumor types, pre-existing T cell infiltrates predict response to checkpoint-based immunotherapy. Based on in vitro pharmacological studies, mouse models and analyses of human melanoma patients, we show that the cytokine GDF-15 impairs LFA-1/β2-integrin-mediated adhesion of T cells to activated endothelial cells, which is a pre-requisite of T cell extravasation. In melanoma patients, GDF-15 serum levels strongly correlate with failure of PD-1-based immune checkpoint blockade therapy. Neutralization of GDF-15 improves both T cell trafficking and therapy efficiency in murine tumor models. Thus GDF-15, beside its known role in cancer-related anorexia and cachexia, emerges as a regulator of T cell extravasation into the tumor microenvironment, which provides an even stronger rationale for therapeutic anti-GDF-15 antibody development

    Interaction of secreted proteins of Staphylococcus aureus and host immune response

    No full text
    Staphylococcus aureus ist ein grampositives Bakterium, welches häufig als kommensaler Besiedler auf der Nasen- und Rachenschleimhaut von Säugetieren vorkommt. Darüber hinaus besitzt dieser fakultativ pathogene Mikroorganismus die Fähigkeit schwer zu behandelnde Krankenhausinfektionen auszulösen. Aufgrund der weiten Verbreitung von Antibiotikaresistenzen und dem Mangel an effektiven Therapien, verursachen S. aureus Infektionen jährlich enorme Kosten für das Gesundheitssystem. S. aureus wird meist von der Nase zum primären Infektionsort übertragen, wodurch zunächst sehr häufig Wund- und Weichteilinfektionen hervor gerufen werden. Von diesem primären Infektionsort ausgehend, kann der Erreger tiefer liegende Gewebsschichten infizieren oder sich über den Blutstrom im gesamten Organismus ausbreiten. Das Spektrum an Krankheitsbildern reicht von leichten Abszessen der Haut bis zu schweren, lebensbedrohlichen Erkrankungen wie Pneumonien und akuter Sepsis. Für die erfolgreiche Kolonisierung und Infektion des Wirtes exprimiert S. aureus eine Vielzahl unterschiedlicher Virulenzfaktoren. Die wohl größte Gruppe an Virulenzfaktoren umfasst die Proteine, die an der Immunevasion und der Umgehung von verschiedenen Abwehrstrategien des Immunsystems beteiligt sind. Das bisherige Wissen über die Interaktion von S. aureus mit dem Immunsystem des Wirtes und die zugrunde liegenden Pathogenitätsmechanismen ist bisher limitiert. Um neue Erkenntnisse über die Interaktion von Wirt und Pathogen zu erlangen, wurden im Rahmen dieser Arbeit bislang unbekannte sekretierte und Oberflächen-assoziierte Proteine von S. aureus funktionell charakterisiert. Die Funktion der ausgewählten Proteine wurde in vitro hinsichtlich Einfluss auf Komponenten des Immunsystems, Adhäsion an Wirtsfaktoren und Invasion in eukaryotische Zellen untersucht. Mit Hilfe der vorangegangenen in-vitro-Charakterisierung der putativen Virulenzfaktoren, konnte für die cytoplasmatische Adenylosuccinat-Synthase PurA eine neuartige Funktion identifiziert werden. PurA ist bekannt als essentielles Enzym der de novo Purin-Synthese. In dieser Arbeit wurde nun gezeigt, dass PurA zudem an der Immunevasion beteiligt ist. Durch die Bindung des humanen Faktor H des Komplementsystems schützt PurA S. aureus vor der lytischen Aktivität des Komplementsystems und verhindert die Opsonisierung des Pathogens. Basierend auf diesen Ergebnissen wurde PurA detailliert charakterisiert. In Bindungsstudien mit rekombinantem Faktor H und PurA wurde eine direkte Interaktion beider Proteine nachgewiesen, wobei Faktor H mit dem N-terminalen Bereich von PurA interagiert. Weiterhin konnte PurA durch Immunfluoreszenz und FACS-Analysen auf der Zelloberfläche nachgewiesen werden, wo es wahrscheinlich mit der Zellwand assoziiert vorliegt. Dort rekrutiert es Faktor H an die bakterielle Oberfläche und verhindert das Fortschreiten der Komplement-Kaskade und damit die Lyse des Pathogens. Aufgrund der Multifunktionalität zählt PurA somit zur Gruppe der Moonlighting Proteine. Des Weiteren wurde die Rolle von PurA im Infektionsgeschehen in zwei unabhängigen Tiermodellen untersucht. In beiden Modellen wurde ein signifikant reduziertes Virulenzpotential der ΔpurA-Mutante beobachtet. Zukünftig soll geklärt werden, ob die verminderte Virulenz in der fehlenden Komplementevasion oder im Defekt in der Purin-Synthese begründet ist. Aufgrund der sehr starken Attenuation in allen untersuchten Infektionsmodellen sollte PurA als potentielles Target für eine Therapie von S. aureus Infektionen weiter charakterisiert werden. Im Ergebnis dieser Arbeit wurde demnach mit PurA ein neues Moonlighting Protein identifiziert, das als Inhibitor des Komplementsystems wesentlich zur Immunevasion von S. aureus beiträgt. Für das bessere Verständnis der humoralen S. aureus-spezifischen Immunantwort, Unterschieden in der Antikörperantwort und der gebildeten Antikörperspezifitäten wurde weiterhin das während der Kolonisierung und Infektion gebildete S. aureus-spezifische Antikörperprofil untersucht. Dazu wurden Plasmen von humanen nasalen Trägern und Nicht-Trägern sowie murine Seren von infizierten Tieren untersucht. Insbesondere wurde das Pathogen-spezifische Antikörperprofil in unterschiedlichen Infektionsmodellen mit Hilfe eines Proteinarrays analysiert, der im Rahmen dieser Arbeit in einer Kooperation mit der Firma Alere Technologies (Jena, Deutschland) und universitären Forschergruppen der Universitäten Greifswald, Münster und Jena mitentwickelt wurde. Die Antikörperprofile von intramuskulär und intravenös infizierten Tieren resultierten in jeweils spezifischen Antikörperprofilen. Diese Ergebnisse deuten auf einen Zusammenhang zwischen der Art der Infektion und der gebildeten Antikörperspezifitäten hin. Wahrscheinlich beruht dies auf einer gewebespezifischen Genexpression als Anpassung an die individuellen Bedürfnisse im Wirtsorganismus. Das ausgebildete Antikörperprofil gibt somit einen Einblick in das Expressionsmuster von Virulenzfaktoren von S. aureus unter in vivo Bedingungen und trägt damit zum Verständnis der komplexen Interaktion von Pathogen und Wirt bei. Diese Untersuchungen ergänzen zudem die bisherigen Kenntnisse über die Anpassung der humoralen Immunantwort an eine asymptomatische Kolonisierung im Gegensatz zu einer akuten Infektion durch S. aureus. Darüber hinaus können die gewonnenen Ergebnisse für diagnostische Zwecke und zur Identifikation von neuen Zielstrukturen für eine Vakzin-Entwicklung genutzt werden.S. aureus is a gram-positive bacterium that is prevalent in animals. It is part of the commensal nasal and respiratory flora. Moreover, it has the ability to transform into a pathogenic micro-organism, thereby eliciting different diseases including hospital-associated infections. S. aureus is transmitted via direct contact from nasal mucosa to the site of infection where it may provoke skin and soft tissue infections. Due to the rapid development of resistance to antibiotics and a current lack of effective treatment options, S. aureus infections cause enormous costs for the health-care system. Starting from the primary site of infection, S. aureus invades into deeper tissues and into the bloodstream during the course of the infection. This leads to a dissemination of the pathogen in the body and is associated with a broad spectrum of diseases including skin abscesses, pneumonia or even acute septicaemia. The pathogen S. aureus produces a multitude of virulence factors that help to colonize and infect the human host. Probably the most extensive group habours proteins involved in immune evasion and circumvent different host defence mechanisms. Understanding of the interaction between S. aureus and the host immune response and the underlying pathogenicity mechanism is still limited. As a part of this work, the interaction of novel secreted and surface-associated proteins of S. aureus with the host immune response was investigated in order to expand the knowledge of host pathogen interactions. Therefore, the function of thus far uncharacterized extracellular proteins of S. aureus was investigated in vitro in relation to influence on components of the immune system, adhesion to host factors and invasion in eukaryotic cells. By using results from previous in vitro characterization of putative virulence factors, a novel function of cytoplasmic adenylosuccinate synthetase PurA was identified. Beside the catalytic reaction during de novo purine synthesis, PurA is independently involved in immune evasion. By binding human complement regulators such as factor H, it protects the bacteria from the lytic activity of the human complement system and prevents the opsonization of the pathogen. The progression of the complement cascade on the bacterial surface is prevented by recruiting complement FH. On the basis of these findings, the moonlighting protein PurA was therefore characterized in detail. In this, the binding between both interaction partners FH and PurA was analysed first. Moreover, it was shown that the cytosolic protein PurA is also associated with the bacterial cell wall. Besides the in vitro characterization of PurA, the impact of the multitasking protein of S. aureus on virulence was investigated in vivo. Therefore ΔpurA deletion mutants were studied regarding their virulence potential in the alternative animal model Galleria mellonella as well as in mice. Due to the reduced virulence of ΔpurA deletion mutants in all investigated animal models, PurA was suggested as a potential target for antibiotic treatment during S. aureus infection. In summary, the moonlighting protein PurA enlarges the spectrum of immune evasion strategies used by S. aureus with a complement system inhibitor. For better understanding of the pathogen-specific humoral immune response, the differences in antibody response and specificities were investigated in human plasma of nasal carriers and non-carriers as well as in murine sera of infected animals. Moreover, the anti-S. aureus antibody profile developed during infection was characterized depending on the type of infection by using a protein array that was co-developed in cooperation with the company Alere technologies (Jena, Germany) and university research groups from Greifswald, Münster and Jena. The results of the differentially infected mice indicated a relationship between developed antibody specificities and type of infection which is likely due to differential gene expression as an adaptation to individual requirements in the host environment. The results give insights into the expression pattern of virulence factors of S. aureus under in vivo conditions contributing to the understanding of the highly complex interaction between pathogen and host. Moreover, these findings supplement the current experience in the adaptations of the humoral immune response to asymptomatic colonization and acute infection. The results gained from this study can be used as a diagnostic tool or for target identification in the development of vaccine

    Reactive and regulative temperament in patients with compulsive buying and non-clinical controls measured by self-report and performance-based tasks

    No full text
    OBJECTIVE: To examine reactive and regulative temperament in patients with compulsive buying (CB) by means of self-report measures and performance-based tasks and to explore the relationship between both measurement approaches. METHOD: The study included 31 treatment-seeking patients with CB (25 women, 6 men) and an age and gender matched non-clinical control group without CB (CG). All participants answered the Compulsive Buying Scale (CBS). Reactive temperament was assessed using the Behavioral Inhibition System/Behavioral Activation System Scales (BIS/BAS) and the Iowa Gambling Task (IGT). Regulative temperament was measured using the Effortful Control subscale of the Adult Temperament Questionnaire (ATQ-EC) and a computerized version of the Stroop Task. To control the results for depression, the Patient Health Questionnaire-Depression Scale (PHQ-9) was administered. RESULTS: Crude group comparisons revealed higher BIS and BAS scores, poorer IGT performance and lower ATQ-EC scores in the CB-group compared to the CG. The groups did not differ in their performance on the Stroop task. After controlling for depressive symptoms that were significantly higher in the CB-group, only the group differences in BAS reactivity remained significant. No significant associations were found between questionnaires and performance-based tasks. CONCLUSION: Overall, the findings indicate that CB in the present clinical sample of treatment-seeking patients was mainly associated with higher approach tendencies and more depressive symptoms. The lacking correlation between self-reports and performance-based tasks is in line with prior research and suggests that both methodologies tap into different aspects of temperament.publisher: Elsevier articletitle: Reactive and regulative temperament in patients with compulsive buying and non-clinical controls measured by self-report and performance-based tasks journaltitle: Comprehensive Psychiatry articlelink: http://dx.doi.org/10.1016/j.comppsych.2014.05.011 content_type: article copyright: Copyright © 2014 Elsevier Inc. All rights reserved.status: publishe

    Comparing Self-Report Measures of Internalized Weight Stigma: The Weight Self-Stigma Questionnaire versus the Weight Bias Internalization Scale

    Get PDF
    <div><p>Background</p><p>Internalized weight stigma has gained growing interest due to its association with multiple health impairments in individuals with obesity. Especially high internalized weight stigma is reported by individuals undergoing bariatric surgery. For assessing this concept, two different self-report questionnaires are available, but have never been compared: the Weight Self-Stigma Questionnaire (WSSQ) and the Weight Bias Internalization Scale (WBIS). The purpose of the present study was to provide and to compare reliability, convergent validity with and predictive values for psychosocial health outcomes for the WSSQ and WBIS.</p><p>Methods</p><p>The WSSQ and the WBIS were used to assess internalized weight stigma in <i>N</i> = 78 prebariatric surgery patients. Further, body mass index (BMI) was assessed and body image, quality of life, self-esteem, depression, and anxiety were measured by well-established self-report questionnaires. Reliability, correlation, and regression analyses were conducted.</p><p>Results</p><p>Internal consistency of the WSSQ was acceptable, while good internal consistency was found for the WBIS. Both measures were significantly correlated with each other and body image. While only the WSSQ was correlated with overweight preoccupation, only the WBIS was correlated with appearance evaluation. Both measures were not associated with BMI. However, correlation coefficients did not differ between the WSSQ and the WBIS for all associations with validity measures. Further, both measures significantly predicted quality of life, self-esteem, depression, and anxiety, while the WBIS explained significantly more variance than the WSSQ total score for self-esteem.</p><p>Conclusions</p><p>Findings indicate the WSSQ and the WBIS to be reliable and valid assessments of internalized weight stigma in prebariatric surgery patients, although the WBIS showed marginally more favorable results than the WSSQ. For both measures, longitudinal studies on stability and predictive validity are warranted, for example, for weight-related and psychosocial outcomes.</p></div

    Global antibody response to Staphylococcus aureus live-cell vaccination

    Get PDF
    The pathogen Staphylococcus aureus causes a broad range of severe diseases and is feared for its ability to rapidly develop resistance to antibiotic substances. The increasing number of highly resistant S. aureus infections has accelerated the search for alternative treatment options to close the widening gap in anti-S. aureus therapy. This study analyses the humoral immune response to vaccination of Balb/c mice with sublethal doses of live S. aureus. The elicited antibody pattern in the sera of intravenously and intramuscularly vaccinated mice was determined using of a recently developed protein array. We observed a specific antibody response against a broad set of S. aureus antigens which was stronger following i.v. than i.m. vaccination. Intravenous but not intramuscular vaccination protected mice against an intramuscular challenge infection with a high bacterial dose. Vaccine protection was correlated with the strength of the anti-S. aureus antibody response. This study identified novel vaccine candidates by using protein microarrays as an effective tool and showed that successful vaccination against S. aureus relies on the optimal route of administration
    corecore