Deregulation of the expression human beta defensin 1 (DEFB1), an antimicrobial peptide, has been implicated in the pathogenesis of COPD and asthma. Since the molecular mechanisms that regulate DEFB1 gene expression are widely unknown, the epigenetic processes involved in the regulation of the constitutive expression of DEFB1 in lung epithelial cells (A549) were investigated. The data demonstrate that histone deacetylases (HDACs) participate in the regulation of DEFB1 gene expression. Inhibition of the class I HDACs, HDACs 1-3, increases DEFB1 gene expression in A549 cells. Chromatin immunoprecipitation (ChIP) assays revealed that the inhibition of the class I HDACs also results in modifications of the chromatin at the DEFB1 promoter. Histone modifications, histone H3 acetylation and H3K4 trimethylation, that are associated with transcriptional activation, were found to increase after inhibition of HDACs 1-3. Finally, RNAi knockdown experiments identified HDAC1 as the sole HDAC responsible for maintaining the constitutive level of DEFB1 transcription. Taken together, our data reveal epigenetic mechanisms which are the basis of the maintenance of the constitutive gene expression of human beta defensin 1.
Although airway epithelia are primarily devoted to gas exchange, they have to fulfil a number of different tasks including organ maintenance and the epithelial immune response to fight airborne pathogens. These different tasks are at least partially accomplished by specialized cell types in the epithelium. In addition, a proximal to distal gradient mirroring the transition from airflow conduction to real gas exchange, is also operative. We analysed the airway system of larval Drosophila melanogaster with respect to region-specific expression in the proximal to distal axis. The larval airway system is made of epithelial cells only. We found differential expression between major trunks of the airways and more distal ones comprising primary, secondary and terminal ones. A more detailed analysis was performed using DNA-microarray analysis to identify cohorts of genes that are either predominantly expressed in the dorsal trunks or in the primary/secondary/terminal branches of the airways. Among these differentially expressed genes are especially those involved in signal transduction. Wnt-signalling associated genes for example are predominantly found in secondary/terminal airways. In addition, some G-protein coupled receptors are differentially expressed between both regions of the airways, exemplified by those activated by octopamine or tyramine, the invertebrate counterparts of epinephrine and norepinephrine. Whereas the OAMB is predominantly found in terminal airway regions, the oct3βR has higher expression levels in dorsal trunks. In addition, we observed a significant association of both, genes predominantly expressed in dorsal trunks or in primary to terminal branches branches with those regulated by hypoxia. Taken together, this observed differential expression is indicative for a proximal to distal transcriptional regionalization presumably reflecting functional differences in these parts of the fly’s airway system.
Objective: To safeguard key workers involved in development and production of medicines and ensure business continuity, we developed an occupational healthcare program, performed by our company's occupational healthcare services, to assess the infection and immune status for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This pilot program, conducted at our company facilities, evaluated the suitability of diagnostic tools in our setting for program upscaling. Methods: We used different marketed in vitro diagnostics (including tests for antibodies against spike protein subunits S1 and S2 and nucleocapsid [N] protein) combined with medical history, symptoms and likelihood of infection. We evaluated the testing strategy over four visits in 141 employees (known positive COVID-19 history, n ¼ 20; unknown status, n ¼ 121) between April and June 2020 at four company locations in Germany. Digital self-monitoring over the pilot program duration was also included. Results: No incident infections were detected. Based on immune status, medical history and likelihood of infection, 10 participants (8.3%) with previously unknown history of COVID-19 were identified to have been infected before entering the program. These participants, who recalled no or mild symptoms in the preceding months, were primarily identified using an assay that detected both S1 and S2 immunoglobulin (Ig) G. The frequency of positive lateral flow assay (LFA) results (IgM or IgG directed against the N-protein) in this cohort was lower compared with participants with a known history of COVID-19 (0-10.8% vs. 33.8-75.7%, respectively). Conclusions: Data from this pilot program suggest that LFA for antibodies may not always reliably detect current, recent or past infections; consequently, these have not been included in our upscaled occupational healthcare program. Regular testing strategies for viral RNA and antibodies directed against different SARS-CoV-2 proteins, combined with hygiene rules and a comprehensive baseline assessment, are recommended to ensure avoidance of infections at workplace as reliably as possible.
Abb. 1: Das Gal4/UAS-System ist eines von mehreren binären Systemen, die zur Expressionssteuerung bei Drosophila zur Verfügung stehen. A, Treiber-Linien exprimieren den Transkriptionsfaktor Gal4 in gewebsspezifischer Weise. B, In der Effektor-oder UAS-Linie steht ein Zielgen (bei Überexpressionsstudien) oder aber ein RNAi-Konstrukt (bei gene silencing-Experimenten) unter transkriptioneller Kontrolle des UAS-Enhancers. C, Die Kreuzung beider Linien bringt den Transkriptionsfaktor Gal4 (allerdings nur in den Zellen, in denen er auch tatsächlich exprimiert wird) und das dazugehörige Enhancerelement (UAS) mit dem Zielgen (unter der Kontrolle des UASEnhancers) zusammen, was zur Transkription des Zielgens führt. D, Als Beispiel haben wir einen tracheenspezifischen Treiber (ppk4-Gal4) mit einer Effektorlinie gekreuzt, die gfp als Zielgen trägt.
11 12 13 14 15 47 The Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling 48 system is of central importance for several critical physiological processes including 49 development, tissue homeostasis, and immune responses . Various cytokines, growth 50 factors, and related signaling compounds signal via this evolutionarily conserved system 51 . The JAK/STAT signaling pathway effectively transduces external signals into desired 52 cellular responses despite having relatively few essential components. Signaling via this 53 pathway is therefore straightforward and allows environmental factors to directly 54 influence transcriptional activity in cells, thereby linking important biological processes 55 with environmental cues . Moreover, JAK/STAT signaling is tightly associated with a 56 great variety of immune responses. JAK/STAT signaling acts downstream of a plethora of 57 cytokines that transmit immune-related information and is, therefore, a central hub in 58 various immunocompetent cells [4-7]. Deregulation of this signaling pathway is directly 59 linked with numerous human diseases, including cancer and inflammatory diseases [5, 8, 60 9]. 61 Lung diseases are often associated with deregulated JAK/STAT signaling. Such 62 deregulation can arise due to mutations and polymorphisms in genes associated with 63 JAK/STAT signaling. In addition, this signaling is activated by stressors, infections, and 64 injuries. This might cause sustained chronic inflammation of the airways and/or alveoli, 65 which is closely associated with the onset and chronification of various lung diseases.66 Niu et al. JAK/STAT signaling in the larval trachea of Drosophila 5 Chronic obstructive pulmonary disease (COPD), asthma, idiopathic pulmonary fibrosis, 67 and lung cancer are causally associated with deregulated JAK/STAT signaling . This 68 signaling is not only of great importance during organ development, but also plays a 69 central role in maintaining tissue and immune homeostasis, especially in response to 70 stressors, infection, and damage [11, 12]. Functional JAK/STAT signaling is required to 71 cope with stressful stimuli such as hyperoxia in the airway epithelium . Deregulation 72 of this signaling in the airways is associated with pathological states. Specifically, 73 chronically reduced JAK/STAT signaling is associated with impaired repair capacities , 74 while increased JAK/STAT signaling leads to cell proliferation that can cause cancer . 75 Despite its simple general organization, the JAK/STAT signaling pathway is characterized 76 by multiple redundancies in vertebrates. A multitude of elements function at each level 77 of the JAK/STAT signaling pathway; for example, more than 50 cytokines can activate this 78 pathway . Moreover, deregulation of JAK/STAT signaling in different motile and 79 resident cell types found in the lungs is associated with chronic lung diseases. Therefore, 80 models with a much simpler JAK/STAT pathway and a less complicated cellular 81 compo...
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