224 research outputs found
Role of the inflammatory molecule IkB kinase 2 in macrophage polarization
No full textMaster thesis - University of Veterinary Medicine Vienna - 2020Macrophages are specialized phagocytic cells and key players of the immune system. They can be separated into subpopulations on the basis of their anatomic location and differentiate from precursors into various polarized phenotypes. The polarization process is plastic, influenced by the environment, metabolism, and signalling pathways and results in either a pro-inflammatory (M1-like MΦ) or an anti-inflammatory (M2-like MΦ) phenotype, which is responsible for host defence and wound healing. The NF-κB signalling pathway is crucial for immune functions and can be separated into two branches: The canonical and the non-canonical branch. IκB kinase (IKK2) 2 is an important activator of the canonical NF-κB branch. Most inflammatory and NF-κB activating pathways converge at the level of IKK2 and IKK2 mediates the immune response in multiple immune cells including macrophages. A better understanding of how macrophage polarization is affected in chronic inflammation may help identifying new therapeutic strategies. For this purpose, macrophages expressing a constitutive active form of IKK2 ((ca)IKK2) - being in a chronically inflamed state due to a constant active NF-κB pathway - were compared with healthy wildtype macrophages. Peritoneal and alveolar macrophages were isolated and either kept as naïve macrophages or stimulated to polarize towards M1- or M2-like macrophage phenotypes. The polarized phenotypes were investigated in regard to gene expression, subpopulations, secreted cytokines and phagocytic activity. Our data show that peritoneal and alveolar macrophages display different phenotypic characteristics that might be based on their different anatomic locations, environment and tissue characteristics. Moreover, our findings suggest that chronic inflammation results in mildly impaired polarization of (ca)IKK2 macrophages towards the M1-like MΦ phenotype. This impaired M1-like MΦ activation was more pronounced in alveolar macrophages than in peritoneal macrophages. In conclusion, chronic inflammation affects the polarization of macrophages in an unexpected way probably with the aim to dampen overshooting inflammation. In order to gain deeper insights into this polarization process, more details about metabolic functions and changes need to be collected.Master thesis - University of Veterinary Medicine Vienna - 2020Macrophages are specialized phagocytic cells and key players of the immune system. They can be separated into subpopulations on the basis of their anatomic location and differentiate from precursors into various polarized phenotypes. The polarization process is plastic, influenced by the environment, metabolism, and signalling pathways and results in either a pro-inflammatory (M1-like MΦ) or an anti-inflammatory (M2-like MΦ) phenotype, which is responsible for host defence and wound healing. The NF-κB signalling pathway is crucial for immune functions and can be separated into two branches: The canonical and the non-canonical branch. IκB kinase (IKK2) 2 is an important activator of the canonical NF-κB branch. Most inflammatory and NF-κB activating pathways converge at the level of IKK2 and IKK2 mediates the immune response in multiple immune cells including macrophages. A better understanding of how macrophage polarization is affected in chronic inflammation may help identifying new therapeutic strategies. For this purpose, macrophages expressing a constitutive active form of IKK2 ((ca)IKK2) - being in a chronically inflamed state due to a constant active NF-κB pathway - were compared with healthy wildtype macrophages. Peritoneal and alveolar macrophages were isolated and either kept as naïve macrophages or stimulated to polarize towards M1- or M2-like macrophage phenotypes. The polarized phenotypes were investigated in regard to gene expression, subpopulations, secreted cytokines and phagocytic activity. Our data show that peritoneal and alveolar macrophages display different phenotypic characteristics that might be based on their different anatomic locations, environment and tissue characteristics. Moreover, our findings suggest that chronic inflammation results in mildly impaired polarization of (ca)IKK2 macrophages towards the M1-like MΦ phenotype. This impaired M1-like MΦ activation was more pronounced in alveolar macrophages than in peritoneal macrophages. In conclusion, chronic inflammation affects the polarization of macrophages in an unexpected way probably with the aim to dampen overshooting inflammation. In order to gain deeper insights into this polarization process, more details about metabolic functions and changes need to be collected.Masterarbeit - Veterinärmedizinische Universität Wien - 2020Makrophagen sind phagozytierende Zellen und Schlüsselakteure im Immunsystem. Sie werden aufgrund ihrer anatomischen Lage in Subpopulationen unterteilt und differenzieren sich aus Vorläuferzellen in verschieden polarisierte Phänotypen. Der Polarisierungsprozess ist plastisch und wird von der Umgebung, dem Stoffwechsel und den Signalwegen beeinflusst. Er führt entweder zu einem proinflammatorischen Phänotyp (M1), der für die Wirtsabwehr verantwortlich ist, oder einem entzündungshemmenden Phänotyp (M2), der die Wundheilung reguliert. Der NF-κB Signalweg ist von entscheidender Bedeutung für die Immunfunktionen und wird in einen kanonischen und einen nicht-kanonischen Signalweg geteilt. Ein wichtiges Molekül des kanonischen NF-κB Signalweges ist IKK2 (IκB kinase 2), da eine Vielzahl NF-κB-aktivierender Signalwege auf der Ebene von IKK2 konvergieren und IKK2 die Immunantwort zahlreicher Immunzellen einschließlich Makrophagen beeinflusst. Ein besseres Verständnis der Auswirkungen chronischer Entzündung auf die Polarisierung von Makrophagen kann dazu beitragen, neue Therapiestrategien zu identifizieren. Für die Experimente wurden murine Makrophagen, die aufgrund eines konstant aktiven NF-κB ((ca)IKK2) Signalwegs eine chronische Entzündung aufweisen, mit gesunden Wildtyp-Makrophagen verglichen. Peritoneale und alveolare Makrophagen wurden isoliert und entweder als naïve Makrophagen kultiviert oder stimuliert, um M1- oder M2-Phänotypen zu generieren. Die polarisierten Phänotypen wurden hinsichtlich Genexpression, Subpopulationen, sezernierter Zytokine sowie Phagozytoseaktivität untersucht. Unsere Daten zeigen, dass peritoneale und alveolare Makrophagen unterschiedliche phänotypische Merkmale aufwiesen, die möglicherweise auf die unterschiedliche anatomische Lage, ihre Umgebung und die Gewebeeigenschaften zurückzuführen sind. Die Ergebnisse geben Grund zur Annahme, dass eine chronische Entzündung zu charakteristischen Veränderungen der Makrophagen-Polarisation führt, wobei eine leicht verminderte Polarisation in Richtung des M1-Phänotyps bei den (ca)IKK2 Makrophagen im Vergleich zu Wildtyp-Makrophagen zu erkennen war. Diese beeinträchtigte M1 Polarisierung war bei den alveolaren Makrophagen ausgeprägter als bei den peritonealen Makrophagen. Zusammenfassend lässt sich festhalten, dass eine chronische Entzündung die Polarisierung von Makrophagen beeinflusst, es aber mehr Informationen über Stoffwechselfunktionen und -veränderungen der Makrophagen bedarf, um einen detaillierten Einblick in diese Polarisierungsprozesse zu gewinnen
CD13/aminopeptidase N is a negative regulator of mast cell activation.
No full textAntigen-induced mast cell (MC) activation via cross-linking of IgE-bound high-affinity receptors for IgE (Fc?RI) underlies type I allergy and anaphylactic shock. Comprehensive knowledge of Fc?RI regulation is thus required. We have identified a functional interaction between Fc?RI and CD13 in murine MCs. Antigen-triggered activation of IgE-loaded Fc?RI results in cocapping and cointernalization of CD13 and equivalent internalization rates of up to 40%. Cointernalization is not unspecific, because ligand-driven KIT internalization is not accompanied by CD13 internalization. Moreover, antibody-mediated cross-linking of CD13 causes IL-6 production in an Fc?RI-dependent manner. These data are indicative of a functional interaction between Fc?RI and CD13 on MCs. To determine the role of this interaction, CD13-deficient bone marrow-derived MCs (BMMCs) were analyzed. Intriguingly, antigen stimulation of CD13-deficient BMMCs results in significantly increased degranulation and proinflammatory cytokine production compared to wild-type cells. Furthermore, in a low-dose model of passive systemic anaphylaxis, antigen-dependent decrease in body temperature, reflecting the anaphylactic reaction, is substantially enhanced by the CD13 inhibitor bestatin (-5.9 ± 0.6°C) and by CD13 deficiency (-8.8 ± 0.6°C) in contrast to controls (-1.2 ± 1.97°C). Importantly, bestatin does not aggravate anaphylaxis in CD13-deficient mice. Thus, we have identified CD13 as a novel negative regulator of MC activation in vitro and in vivo-Zotz, J. S., Wölbing, F., Lassnig, C., Kauffmann, M., Schulte, U., Kolb, A., Whitelaw, B., Müller, M., Biedermann, T., Huber, M. CD13/aminopeptidase N is a negative regulator of mast cell activation
Diazepam leads to enhanced severity of orthopoxvirus infection and immune suppression
No full textBenzodiazepines are drugs widely used as tranquilizers and in various other indications. We treated Balb/c mice with diazepam and infected them with cowpox (CPXV) and vaccinia virus (VACV). Disease index, weight loss and the antibody response were determined. Additionally the influence of different benzodiazepines on the mitogen response of human peripheral blood lymphocytes and spleen cells was tested. Diazepam led to earlier disease onset, prolonged duration of symptoms, higher weight loss and overall disease index in VACV infected mice. CPXV infected mice developed poxviral skin lesions only after drug administration and a significant decrease in the specific antibody response was also observed. Diazepam and alprazolam also inhibited the proliferative response of human lymphocytes/spleen cells in vitro but did not show noteworthy apoptotic effects. It is surprising that even a single dose of diazepam has a profound influence on the immune system, sufficient to facilitate symptomatic infectious disease. These data provide first evidence that commonly used drugs like Valium(®) may augment severity of rare poxvirus infections such as CPXV or monkeypox. As VACV is still used as life vaccine against smallpox there is also a risk of enhanced side effects or possible interference with the success of vaccination
Primed T Cell Responses to Chemokines Are Regulated by the Immunoglobulin-Like Molecule CD31
No full textPMCID: PMC3378580This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Effect of Different Ambient Temperatures on Reproductive Outcome and Stress Level of Lactating Females in Two Mouse Strains
No full textSIMPLE SUMMARY: The optimal temperature for laboratory mice has been under discussion for some time. Current standard temperature is 20 °C–24 °C but it has been suggested to elevate the standard to 30 °C, which is the thermoneutral zone for mice. In this study, the effect of different cage temperatures (20 °C, 25 °C, 30 °C) on reproduction and stress hormone metabolite excretion was evaluated in lactating females of two commonly used mouse strains. Pup loss was higher, and weights of mothers and pups were reduced at 30 °C compared to the lower temperatures. In addition, pups showed increased tail length at weaning under the high temperature (30 °C). There was no difference in stress hormone metabolite excretion in mice between temperature groups. We could not show any detrimental effects of the lower or higher cage temperature on stress hormone metabolite excretion, but found decreased reproductive outcome under the higher temperature. ABSTRACT: Ambient temperature is an important non-biotic environmental factor influencing immunological and oncological parameters in laboratory mice. It is under discussion which temperature is more appropriate and whether the commonly used room temperature in rodent facilities of about 21 °C represents a chronic cold stress or the 30 °C of the thermoneutral zone constitutes heat stress for the animals. In this study, we selected the physiological challenging period of lactation to investigate the influence of a cage temperature of 20 °C, 25 °C, and 30 °C, respectively, on reproductive performance and stress hormone levels in two frequently used mouse strains. We found that B6D2F1 hybrid mothers weaned more pups compared to C57BL/6N mothers, and that the number of weaned pups was reduced when mothers of both strains were kept at 30 °C. Furthermore, at 30 °C, mothers and pups showed reduced body weight at weaning and offspring had longer tails. Despite pronounced temperature effects on reproductive parameters, we did not find any temperature effects on adrenocortical activity in breeding and control mice. Independent of the ambient temperature, however, we found that females raising pups showed elevated levels of faecal corticosterone metabolites (FCMs) compared to controls. Peak levels of stress hormone metabolites were measured around birth and during the third week of lactation. Our results provide no evidence of an advantage for keeping lactating mice in ambient temperatures near the thermoneutral zone. In contrast, we found that a 30 °C cage temperature during lactation reduced body mass in females and their offspring and declined female reproductive performance
The impact of shelf life on exposure as revealed from quality control data associated with the quargel outbreak
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