Interplay of the impaired tight junction and subjacent immune cells in inflammatory bowel disease

In inflammatory bowel disease (IBD), the homeostasis between intestinal immunity, the epithelial layer and the microbiota is disturbed, resulting in an overreaction of the immune system, barrier damage and inflammation. The two major forms of IBD are Crohn’s disease (CD) and ulcerative colitis (UC). The tight junction (TJ) regulates the passage of solutes between the spaces of adjacent cells. In UC patients the expression of tetra-span TJ-associated Marvel Proteins (TAMPs) including marvelD3 (MD3), occludin (Ocln) and tricellulin (Tric) are altered and thus TAMPs might play a role in the pathogenies of IBD. MD3 and Ocln are known to have more regulatory functions, whereas Tric and the tricellular TJ (tTJ) were found to be directly involved in paracellular macromolecule passage and presumably in immune cell migration. Hence, TAMPs might have immune regulatory functions. To investigate this, mice with intestinal epithelial specific overexpression of either MD3, Ocln or Tric were subjected to dextran sulfate sodium (DSS) induced colitis, which initially targets the epithelium. Intestinal immune cells from the large intestine were isolated and analysed by flow cytometry to ascertain changes in immune cell subtypes due to TAMP overexpression (OE) under control and DSS conditions. Furthermore, RNA was isolated from colon tissue and expression of different pro- and anti-inflammatory cytokines was determined. Results showed that TAMP-OE caused alterations in the composition of subjacent immune cells. MD3-OE showed an increase in the occurrence of CD19+ B-cells, Tric-OE appeared to depress CD103+ subpopulations of both intraepithelial lymphocytes (IEL) and dendritic cells (DC), whereas Ocln-OE supported CD103+ IELs and DCs and additionally facilitated the maintenance of resident, particularly CD4+ resident macrophages in DSS-induced colitis. As another project, organoid derived monolayers (ODM) were established and validated for their ability to mimic in vivo barrier properties. Organoids can fill the gap between traditional cell culture and animal experiments due to the greater complexity compared to cell lines and the better accessibility compared to animals. Moreover, organoids retain donor properties, which makes them a great tool for personalised medicine and many other research topics. Initial studies were performed comparing colon ODMs of healthy controls with those of UC patients. Comparison of duodenum ODMs to Caco-2 cells and duodenal tissue, demonstrated that ODMs reflected well both the para- and the transcellular properties of human duodenum tissue and therefore can be considered as a suitable and good model for barrier research. Initial analysis of colon ODMs from healthy controls and UC patients showed changes in transepithelial resistance (TER) and donor specific TJ-protein expression. In conclusion, the results of the first part could further strengthen the hypothesis that TAMPs not only play a role within in the TJ but also influence neighbouring cells and compartments, as demonstrated here for immune cells. However, further studies need to clarify the outcomes of the changed immune cell composition in more detail and the regulatory mechanisms beyond. In the second project, the ODM model was successfully established in our laboratory and evaluated considering barrier properties indicating that this model reflects well the tissue properties and complexity. ODMs can therefore be used as a more realistic model than conventional epithelial cell lines to elucidate further mechanisms and drug targets for IBD.In chronisch-entzündlichen Darmerkrankungen (CED; inflammatory bowel disease / IBD) ist die Homöostase zwischen dem intestinalen Immunsystem, dem Epithel und der Mikrobiota gestört, dies führt zu einer Überreaktion des Immunsystems, einer beschädigten Barriere und Entzündungen. IBD manifestiert sich in den zwei Hauptformen Morbus Crohn (MC; Crohn’s Disease / CD) und Colitis ulzerosa (CU; ulcerative colitis / UC). Der Durchtritt von Substanzen zwischen zwei benachbarten Zellen wird von der Tight Junction (TJ / Schlüsselleiste) reguliert. In UC-Patienten ist die Expression von TAMPs (TJ-associated Marvel Proteins) welche MarvelD3 (MD3), Occludin (Ocln) und Tricellulin (Tric) einschließen verändert. Es ist bekannt, dass MD3 und Ocln eher regulatorische Funktionen haben, während Tric und die trizelluläre TJ direkt am parazellulären Durchtritt von Makromolekülen und wahrscheinlich auch bei der Migration von Immunzellen beteiligt sind. Aufgrund der Expressionsveränderungen bei CED-Patienten und dieser Funktionen ergibt sich die Hypothese, dass TAMPs eine Rolle bei der Pathogenese von CED spielen und hierbei auch immunregulatorische Funktionen besitzen. Um dies zu untersuchen, wurden Mäuse mit einer intestinalen epithelialen spezifischen Überexpression von entweder MD3, Ocln oder Tric mit Dextransulfat-Natrium behandelt (dextran sulfate sodium / DSS) um eine chemisch-induzierte Kolitis hervorzurufen, welche zunächst das Epithel angreift. Um Veränderungen in Immunzellsubtypen durch die TAMP Überexpression unter Kontroll- und DSS-Bedingungen feststellen zu können, wurden Immunzellen des Dickdarms isoliert und mittels Durchflusszytometrie analysiert. Zusätzlich wurde die Expression von pro- und anti- entzündlichen Zytokinen bestimmt, indem mRNA von Dickdarmgewebe isoliert wurde. Die Ergebnisse zeigten, dass eine TAMP-Überexpression zu Veränderungen in der Immunzellzusammensetzung führte. Bei einer MD3-Überexpression war das Vorkommen von CD19+ B-Zellen erhöht, eine Tric-Überexpression verringerte die CD103+-Unterpopulation von intraepithelialen Lymphozyten (IEL) als auch von dendritischen Zellen (DC), wohingegen eine Ocln-Überexpression zum vermehrten Vorkommen von CD103+ IELs und DCs führte. Zusätzlich unterstützte eine Ocln-Überexpression die Erhaltung von residenten Makrophagen, im speziellen von CD4+ residenten Makrophagen in DSS-induzierter Kolitis. In einem weiteren Projekt wurden intestinale Organoide generiert, daraus erhaltene Einzelzellschichten (organoid derived Monolayers / ODM) in ihrer Verwendung als Modell der epithelialen Barriere etabliert und validiert. Organoide können die Lücke zwischen traditioneller Zellkultur und Tierexperimenten schließen, da sie komplexer als Zelllinien und gleichzeitig leichter verfügbar als Tiermodelle sind. Zusätzlich behalten Organoide spenderspezifische Eigenschaften, was sie zu einem guten Modell in personalisierter Medizin und vielen weiteren Forschungsthemen macht. Ein Vergleich zwischen duodenalen ODMs, Caco-2-Zellen und Duodenumgewebe zeigte, dass ODMs die para- und transzellulären Eigenschaften von humanem Duodenum gut darstellen konnten und daher als ein nützliches und gutes Modell für die Barriereforschung betrachtet werden können. Ein initialer Vergleich zwischen Dickdarm-ODMs von gesunden Kontrollspendern und UC-Patienten wiesen spenderspezifische transepitheliale Widerstände (transepithelial resistance / TER) und TJ-Protein Expressionen auf. Zusammengefasst wurde im ersten Projekt die Hypothese gestärkt, dass TAMPs nicht nur eine Rolle innerhalb der TJ, sondern auch Einfluss auf benachbarte Zellen und weitere Kompartimente haben, wie hier gezeigt für Immunzellen. Nichtsdestotrotz müssen in weiteren Studien die Auswirkungen der veränderten Immunzellzusammensetzung und die regulatorischen Mechanismen dahinter im Detail untersucht werden. Im zweiten Projekt konnten ODMs erfolgreich in unserem Labor etabliert und in Bezug auf Barriereeigenschaften validiert werden. Die Barriereeigenschaften demonstrierten, dass ODMs die Gewebeeigenschaften und Komplexität gut widerspiegeln konnten. ODMs können daher als ein realistischeres Model als konventionelle epitheliale Zelllinien genutzt werden, um weitere Mechanismen und Angriffspunkte für Medikamente in CED zu identifizieren

Internal Sustainability Communication and the Influence on Corporate Culture: A Qualitative Survey of Sustainable Companies in Germany

Nowadays, sustainability is becoming increasingly important not only in society but also in companies. The objective of this study is to determine the potential of internal sustainability communication in shaping the Corporate Culture of sustainable companies. The research questions are dedicated to the goals, measures, and effects of internal sustainability communication with regard to Corporate Culture. To answer these questions, 15 qualitative expert interviews were conducted. A ranking of the 200 most sustainable companies in Germany was chosen as a sample to recruit the interview partners. The study was able to identify diverse potentials of internal sustainability communication with regard to shaping Corporate Culture. When considering the three dimensions of sustainability, it became clear that ecological and social sustainability are increasingly dealt with, while the economic dimension is neglected. This study shows that internal sustainability communication can positively influence the Corporate Culture as a whole and ultimately also individual employees in their attitudes and actions with regard to sustainability issues. However, the potential identified must be considered in the context of the individual Corporate Culture, such as the structural and personnel premises, to be able to discuss the extent to which the potential can be exploited in the best possible way. This study provides starting points for further research in this dynamic field as well as practical insights for application in employee communication

Expression of tricellular tight junction proteins and the paracellular macromolecule barrier are recovered in remission of ulcerative colitis

Background: Ulcerative colitis (UC) has a relapsing and remitting pattern, wherein the underlying mechanisms of the relapse might involve an enhanced uptake of luminal antigens which stimulate the immune response. The tricellular tight junction protein, tricellulin, takes charge of preventing paracellular passage of macromolecules. It is characterized by downregulated expression in active UC and its correct localization is regulated by angulins. We thus analyzed the tricellulin and angulin expression as well as intestinal barrier function and aimed to determine the role of tricellulin in the mechanisms of relapse. Methods: Colon biopsies were collected from controls and UC patients who underwent colonoscopy at the central endoscopy department of Campus Benjamin Franklin, Charite - Universitatsmedizin Berlin. Remission of UC was defined basing on the clinical appearance and a normal Mayo endoscopic subscore. Intestinal barrier function was evaluated by electrophysiological and paracellular flux measurements on biopsies mounted in Ussing chambers. Results: The downregulated tricellulin expression in active UC was recovered in remission UC to control values. Likewise, angulins were in remission UC at the same levels as in controls. Also, the epithelial resistance which was decreased in active UC was restored in remission to the same range as in controls, along with the unaltered paracellular permeabilities for fluorescein and FITC-dextran 4 kDa. Conclusions: In remission of UC, tricellulin expression level as well as intestinal barrier functions were restored to normal, after they were impaired in active UC. This points toward a re-sealing of the impaired tricellular paracellular pathway and abated uptake of antigens to normal rates in remission of UC

The Portable Ice Nucleation Experiment (PINE): A new online instrument for laboratory studies and automated long-term field observations of ice-nucleating particles

Atmospheric ice-nucleating particles (INPs) play an important role in determining the phase of clouds, which affects their albedo and lifetime. A lack of data on the spatial and temporal variation of INPs around the globe limits our predictive capacity and understanding of clouds containing ice. Automated instrumentation that can robustly measure INP concentrations across the full range of tropospheric temperatures is needed in order to address this knowledge gap. In this study, we demonstrate the functionality and capacity of the new Portable Ice Nucleation Experiment (PINE) to study ice nucleation processes and to measure INP concentrations under conditions pertinent for mixed-phase clouds, with temperatures from about −10 to about −40 C. PINE is a cloud expansion chamber which avoids frost formation on the cold walls and thereby omits frost fragmentation and related background ice signals during the operation. The development, working principle and treatment of data for the PINE instrument is discussed in detail. We present laboratory-based tests where PINE measurements were compared with those from the established AIDA (Aerosol Interaction and Dynamics in the Atmosphere) cloud chamber. Within experimental uncertainties, PINE agreed with AIDA for homogeneous freezing of pure water droplets and the immersion freezing activity of mineral aerosols. Results from a first field campaign conducted at the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) observatory in Oklahoma, USA, from 1 October to 14 November 2019 with the latest PINE design (a commercially available PINE chamber) are also shown, demonstrating PINE\u27s ability to make automated field measurements of INP concentrations at a time resolution of about 8 min with continuous temperature scans for INP measurements between −10 and −30 ∘C. During this field campaign, PINE was continuously operated for 45 d in a fully automated and semi-autonomous way, demonstrating the capability of this new instrument to also be used for longer-term field measurements and INP monitoring activities in observatories

Zwischen Schattendasein, Governance und Entrepreneurship - Eine empirische Bestandsaufnahme zum Professionalisierungsgrad des IT-Managements in deutschen Krankenhäusern

Bei der Umsetzung der digitalen Transformation bewegt sich das ITManagement in Krankenhäusern in einem Spannungsfeld aus historischkulturellen Vorbedingungen und den besonderen Herausforderungen wissensintensiver Expertenorganisation. Um zu untersuchen, wie professionell das ITManagement vor diesem Hintergrund ist, wurde in der vorliegenden Studie der Professionalisierungsgrad des IT-Managements als Beschreibungsgröße vorgeschlagen. Darüber hinaus wurden Ausprägungen der IT-Governance und des IT-Entrepreneurships als mögliche Determinanten des Professionalisierungsgrades konzeptionalisiert. Ein entsprechend aufgestelltes, hypothesengeleitetes Untersuchungsmodell wurde anhand der Daten von 164 CIOs deutscher Krankenhäuser überprüft. Die Ergebnisse der Studie deuten auf Professionalisierungspotenziale des IT-Managements im strategischen und evaluierenden Bereich hin. Etablierte Kommunikationskanäle zwischen CIO und Krankenhausleitung sowie eine ausgewiesene IT-Budgetverantwortungen wirkten sich positiv auf den Professionalisierungsgrad aus. Zudem Das agierte das ITManagement umso professioneller, je stärker der IT-Entrepreneurship auf organisatorischer und individueller Ebene ausgeprägt war. Die Ergebnisse können den theoretischen Erkenntnisstand über die Wirkungsweise von IT-Governance und IT-Entrepreneurship erweitern und auf ähnliche, wissensintensive Expertenorganisationen übertragen werden

The regulation of large-scale brain networks via functional magnetic resonance imaging: Neurofeedback as treatment approach

Real-time functional magnetic resonance imaging neurofeedback (rt-fMRI NF) is a non-invasive approach to voluntarily control brain activity. Whereas the first decades since its development have been focussed on Region-of-Interest (ROI)-based rt-fMRI NF that feeds back activity of a single brain region as a target brain process, new approaches are constantly developed. One of these promising new approaches is functional connectivity (FC)-based rt-fMRI NF which is characterized by its focus on network-based brain connectivity. This approach has the advantage to be applicable in a plurality of mental disorders, since brain structures with central functions are known to be disturbed in a variety of mental disorders. Secondly, most mental disorders are characterized by distortions in whole brain networks as opposed to specific areas. Therefore, a strong advantage of the approach would be its application in a transdiagnostic way. Due to their involvement in a variety of mental disorders i.e. schizophrenia, frontostriatal networks are a suitable target network for the application of such approaches. The present dissertation attempted to investigate the feasibility of rt-fMRI NF FC targeting large-scale frontostriatal networks. In a first pre-registered, randomized, double-blind and yoke-controlled proof-of-concept study conducted in a single training session, it was found that application of a large-scale frontostriatal target network including dorsolateral prefrontal cortex (DLPFC), anterior cingulate cortex (ACC) and striatum can be strongly biased by respiratory artefacts. Following up on this, a way to remove the influence of these respiratory artefacts in the offline analyses was found. Global Signal Regression (GSR) and a model-based physiological nuisance regression approach were able to eliminate these detrimental associations and clean the data sufficiently. It was concluded that GSR might be adequate for online data correction for respiratory artefacts. In the subsequent second study, the methodology was elaborated on the basis of the findings from the first study. This included an extension of the training duration from one to three training sessions for demonstration of learning effects and, most importantly, application of GSR to the offline and specifically also the online data. Furthermore, the network was reduced to DLPFC and striatum only to increase adjustability. While the pre-registered significant effect of the NF training could not be proven, we found evidence for a medium effect size in the last NF run on the third training day. In summary, the present dissertation aimed at enhancing the understanding of rt-fMRI NF FC and address its feasibility. It is concluded that extensive NF training is a promising method for generating circuit-specific treatment approaches for mental disorders that could translate to symptom improvements. However, careful correction of data and preceding power analyses to allow for reasonable sample sizes are required in future rt-fMRI NF FC studies

Sustainability in the communication policy and corporate activities of airlines : an analysis of selected airlines

Fluggesellschaften stehen heutzutage vor vielseitigen Herausforderungen. Das erhöhte Umweltbewusstsein in der Gesellschaft und damit einhergehende Phänomene wie Flugscham oder Fridays-for-Future Bewegung zwingen die Airlines immer mehr im Sinne der ökologischen Nachhaltigkeit zu handeln und die umweltbewusste Gesellschaft über ihre Bemühungen zu informieren. Die vorliegende Arbeit beschäftigt sich anhand eines theoretischen Grundgerüsts und einer anschließenden Analyse von ausgewählten Fluggesellschaften damit, wie die Airlines versuchen ökologisch nachhaltig zu handeln und ihre Bemühungen glaubwürdig zu kommunizieren