Bernd Schmeck

Universitätsklinikum Gießen und Marburg, Marburg, Hesse, Germany

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Publications (59)246.85 Total impact

  • Bernd schmeck · Wilhelm Bertrams · Xin Lai · Julio Vera
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    ABSTRACT: Lung diseases cause an enormous socio-economic burden. Four of them are among the ten most important causes of deaths worldwide: Pneumonia has the highest death toll of all infectious diseases, lung cancer kills the most people of all malignant proliferative disorders, chronic obstructive pulmonary disease (COPD) ranks third in mortality among the chronic non-communicable diseases, and tuberculosis is still one of the most important chronic infectious diseases. Despite all efforts, for example by the world health organization and clinical and experimental researchers, these diseases are still highly prevalent and harmful. This unmet need is in part due to the specific organization of tissue homeostasis, architecture, and immunity of the lung. Recently, several consortia have formed and aim to bring together clinical and molecular data from big cohorts of patients with lung diseases with novel experimental setups, biostatistics, bioinformatics, and mathematical modeling. This “Systems Medicine” concept will help to match the different disease modalities with adequate therapeutic and possibly preventive strategies.
    No preview · Chapter · Jan 2016
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    ABSTRACT: The understanding of the immune response is right now at the center of biomedical research. There are growing expectations that immune-based interventions will in the midterm provide new, personalized, and targeted therapeutic options for many severe and highly prevalent diseases, from aggressive cancers to infectious and autoimmune diseases. To this end, immunology should surpass its current descriptive and phenomenological nature, and become quantitative, and thereby predictive.Immunology is an ideal field for deploying the tools, methodologies, and philosophy of systems biology, an approach that combines quantitative experimental data, computational biology, and mathematical modeling. This is because, from an organism-wide perspective, the immunity is a biological system of systems, a paradigmatic instance of a multi-scale system. At the molecular scale, the critical phenotypic responses of immune cells are governed by large biochemical networks, enriched in nested regulatory motifs such as feedback and feedforward loops. This network complexity confers them the ability of highly nonlinear behavior, including remarkable examples of homeostasis, ultra-sensitivity, hysteresis, and bistability. Moving from the cellular level, different immune cell populations communicate with each other by direct physical contact or receiving and secreting signaling molecules such as cytokines. Moreover, the interaction of the immune system with its potential targets (e.g., pathogens or tumor cells) is far from simple, as it involves a number of attack and counterattack mechanisms that ultimately constitute a tightly regulated multi-feedback loop system. From a more practical perspective, this leads to the consequence that today's immunologists are facing an ever-increasing challenge of integrating massive quantities from multi-platforms.In this chapter, we support the idea that the analysis of the immune system demands the use of systems-level approaches to ensure the success in the search for more effective and personalized immune-based therapies.
    No preview · Article · Jan 2016 · Methods in molecular biology (Clifton, N.J.)
  • Bernd Schmeck · Wilhelm Bertrams · Xin Lai · Julio Vera
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    ABSTRACT: Lung diseases cause an enormous socioeconomic burden. Four of them are among the ten most important causes of deaths worldwide: Pneumonia has the highest death toll of all infectious diseases, lung cancer kills the most people of all malignant proliferative disorders, chronic obstructive pulmonary disease (COPD) ranks third in mortality among the chronic noncommunicable diseases, and tuberculosis is still one of the most important chronic infectious diseases. Despite all efforts, for example, by the World Health Organization and clinical and experimental researchers, these diseases are still highly prevalent and harmful. This is in part due to the specific organization of tissue homeostasis, architecture, and immunity of the lung. Recently, several consortia have formed and aim to bring together clinical and molecular data from big cohorts of patients with lung diseases with novel experimental setups, biostatistics, bioinformatics, and mathematical modeling. This "systems medicine" concept will help to match the different disease modalities with adequate therapeutic and possibly preventive strategies for individual patients in the sense of precision medicine.
    No preview · Article · Dec 2015 · Methods in molecular biology (Clifton, N.J.)
  • Alexandra Sittka · Bernd Schmeck
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    ABSTRACT: The lung constitutes one of the most delicate tissue structures in mammalian organisms to accomplish the vital function of gas exchange. On the other hand, its immense surface area, necessary in this context, exhibits the first line of defense against a variety of pro-inflammatory stimuli. MicroRNAs (miRNAs) are a class of post-transcriptional regulators that revolutionized our view of gene expression regulation. By now, it is well established that miRNAs impair all known cellular and developmental processes. Extensive research over the last years revealed not only a fundamental role for miRNAs in lung development and homeostasis, but also in the process of lung inflammation. Lung inflammation occurs in response to stimuli very different in nature (e.g., physical, radioactive, infective, pro-allergenic, or toxic), and in some cases becomes manifest in chronic diseases (e.g., chronic bronchitis/chronic obstructive pulmonary disease (COPD), asthma and allergic airway diseases) or even lung cancer. This review chapter will briefly describe the current knowledge concerning miRNA expression and their exerted target regulation in the course of lung inflammation and lung cancer.
    No preview · Article · Feb 2013 · Advances in Experimental Medicine and Biology
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    Alexandra Sittka · Julio Vera · Xin Lai · Bernd T. Schmeck
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    ABSTRACT: Asthma has a high prevalence worldwide, and causes a significant socio-economic burden. A classical paradigm attributes asthma symptoms to an allergic, Th2-driven airway inflammation causing airway hyperresponsiveness and resulting in reversible airway obstruction. Diagnosis and therapy are mainly based on these pathophysiological concepts, which are increasingly challenged by recent studies, and a frequent failure in controlling asthma symptoms. Important recent findings are e.g., the protective "farm effect" on asthma development in children, the possible prenatal mechanisms of this protection, the recognition of many different asthma phenotypes in children and adults, and the partly disappointing clinical effects of new targeted therapeutic approaches.A more comprehensive view on asthma pathophysiology and a higher success rate of new therapies might arise from systems biology approaches. Systems Biology integrates clinical and experimental data by means of bioinformatics and mathematical modeling. In general, an "-omics" approach, and a "mathematical modeling" approach can be defined. Recently, several consortia aim to bring together clinical and molecular data from big asthma cohorts with novel experimental setups, biostatistics, bioinformatics, and mathematical modeling. This "systems medicine" concept of asthma will help to address the different asthma phenotypes with adequate therapy and possibly preventive strategies.Pediatric Research (2013); doi:10.1038/pr.2013.8.
    Full-text · Article · Jan 2013 · Pediatric Research
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    ABSTRACT: In an "aging society", healthspan extension is most important. As in 2010, talks in this series of meetings in Rostock-Warnemünde demonstrated that aging is an apparently very complex process, where computational work is most useful for gaining insights, and to find interventions that counter aging and prevent or counteract aging-related diseases. The specific topics of this year's meeting were primarily related to "Cancer and Aging", and also had a focus on work funded by the German Federal Ministry of Education and Research (BMBF). The next meeting in the series, scheduled for September/October 2013, shall focus on the use of ontologies for computational research into aging, stem cells and cancer. Promoting knowledge formalization is also at the core of the set of proposed action items concluding this report.
    Full-text · Article · Sep 2012 · Rejuvenation Research
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    ABSTRACT: The release of potent pro-inflammatory mediators is crucial to mounting an efficient host response during infections. However, excessive inflammation may lead to deleterious tissue damage. This is highlighted in severe pneumococcal pneumonia, in which the delicate balance between a robust inflammatory response necessary to kill pneumococci and the loss of organ function determines the outcome of the disease. Therefore, we assessed the regulation of the potent anti-inflammatory cytokine IL-10 in pneumococcal infection via western blot, ELISA and Chromatin immunoprecipitation analysis. S. pneumoniae induced IL-10 expression in mouse lungs and human lung epithelial cells. Pneumococcal infection resulted in a strong induction of Krueppel-like factor 4 (KLF4) expression in vivo and in vitro. The induction of both, IL-10 and KLF4, is mediated by a pathway involving bacterial DNA, TLR9, MyD88, and Src kinase. KLF4 is recruited to the il10 promoter, and siRNA-mediated knockdown of KLF4 expression blocked IL-10 expression during pneumococcal infection. In conclusion, KLF4 is induced in a bacterial DNA-TLR9-Src-dependent manner and regulates IL-10 expression, linking the detection of bacterial DNA by TLR9 to the control of an inflammatory response.
    No preview · Article · May 2012 · European Respiratory Journal

  • No preview · Conference Paper · May 2012
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    ABSTRACT: Chlamydophila pneumoniae causes acute respiratory tract infections and has been associated with development of asthma and atherosclerosis. The production of IL-1β, a key mediator of acute and chronic inflammation, is regulated on a transcriptional level and additionally on a posttranslational level by inflammasomes. In the present study we show that C. pneumoniae-infected human mononuclear cells produce IL-1β protein depending on an inflammasome consisting of NLRP3, the adapter protein ASC and caspase-1. We further found that the small GTPase Rac1 is activated in C. pneumoniae-infected cells. Importantly, studies with specific inhibitors as well as siRNA show that Rac1 regulates inflammasome activation in C. pneumoniae-infected cells. In conclusion, C. pneumoniae infection of mononuclear cells stimulates IL-1β production dependent on a NLRP3 inflammasome-mediated processing of proIL-1β which is controlled by Rac1.
    Full-text · Article · Jan 2012 · PLoS ONE
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    ABSTRACT: Legionella pneumophila is an important causative agent of severe pneumonia in humans. Human alveolar epithelium and macrophages are effective barriers for inhaled microorganisms and actively participate in the initiation of innate host defense. The beta defensin-3 (hBD-3), an antimicrobial peptide is an important component of the innate immune response of the human lung. Therefore we hypothesize that hBD-3 might be important for immune defense towards L. pneumophila. We investigated the effects of L. pneumophila and different TLR agonists on pulmonary cells in regard to hBD-3 expression by ELISA. Furthermore, siRNA-mediated inhibition of TLRs as well as chemical inhibition of potential downstream signaling molecules was used for functional analysis. L. pneumophila induced release of hBD-3 in pulmonary epithelium and alveolar macrophages. A similar response was observed when epithelial cells were treated with different TLR agonists. Inhibition of TLR2, TLR5, and TLR9 expression led to a decreased hBD-3 expression. Furthermore expression of hBD-3 was mediated through a JNK dependent activation of AP-1 (c-Jun) but appeared to be independent of NF-kappaB. Additionally, we demonstrate that hBD-3 elicited a strong antimicrobial effect on L. pneumophila replication. Taken together, human pulmonary cells produce hBD-3 upon L. pneumophila infection via a TLR-JNK-AP-1-dependent pathway which may contribute to an efficient innate immune defense.
    Full-text · Article · Jul 2010 · Respiratory research
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    ABSTRACT: The release of potent proinflammatory mediators is not only central for mounting an efficient host response, but also bears the risk for deleterious excessive tissue-damaging inflammation. This is highlighted in severe pneumococcal pneumonia, in which the delicate balance between a robust inflammatory response to kill pneumococci and loss of organ function determines the outcome of disease. In this study, we tested the hypothesis that Krüppel-like factor (KLF)2 counterregulates pneumococci- and pattern recognition receptor-related human lung cell activation. Pneumococci induced KLF2 expression in vitro and in a murine pneumonia model. Activation of TLR2- and nucleotide-binding oligomerization domain protein 2-related signaling induced KLF2 expression in a PI3K-dependent manner. Overexpression of KLF2 downregulated pneumococci-, TLR2-, and nucleotide-binding oligomerization domain protein 2-related NF-kappaB-dependent gene expression and IL-8 release, whereas small interfering RNA-based silencing of KLF2 provoked an enhanced inflammatory response. KLF2-dependent downregulation of NF-kappaB activity is partly reversible by overexpression of the histone acetylase p300/CREB-binding protein-associated factor. In conclusion, KLF2 may act as a counterregulatory transcription factor in pneumococci- and pattern recognition receptor-related proinflammatory activation of lung cells, thereby preventing lung hyperinflammation and subsequent organ failure.
    Full-text · Article · Jul 2010 · The Journal of Immunology
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    ABSTRACT: Mechanical ventilation (MV) is a life saving intervention in acute respiratory failure without alternative. However, particularly in pre-injured lungs, even protective ventilation strategies may evoke ventilator-induced lung injury (VILI), which is characterized by pulmonary inflammation and vascular leakage. Adjuvant pharmacologic strategies in addition to lung protective ventilation to attenuate VILI are lacking. Simvastatin exhibited anti-inflammatory and endothelial barrier stabilizing properties in vitro and in vivo. Mice were ventilated (12 ml/kg; six hours) and subjected to simvastatin (20 mg/kg) or sham treatment. Pulmonary microvascular leakage, oxygenation, pulmonary and systemic neutrophil and monocyte counts and cytokine release in lung and blood plasma were assessed. Further, lung tissue was analyzed by electron microscopy. Mechanical ventilation induced VILI, displayed by increased pulmonary microvascular leakage and endothelial injury, pulmonary recruitment of neutrophils and Gr-1high monocytes, and by liberation of inflammatory cytokines in the lungs. Further, VILI associated systemic inflammation characterized by blood leukocytosis and elevated plasma cytokines was observed. Simvastatin treatment limited pulmonary endothelial injury, attenuated pulmonary hyperpermeability, prevented the recruitment of leukocytes to the lung, reduced pulmonary cytokine levels and improved oxygenation in mechanically ventilated mice. High-dose simvastatin attenuated VILI in mice by reducing MV-induced pulmonary inflammation and hyperpermeability.
    Full-text · Article · May 2010 · Critical care (London, England)
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    ABSTRACT: Community-acquired pneumonia is a very common infectious disease associated with significant morbidity and mortality. Streptococcus pneumoniae is the predominant pathogen in this disease, and pneumococcal resistance to multiple antibiotics is increasing. The recently purified bacteriophage endolysin Cpl-1 rapidly and specifically kills pneumococci on contact. The aim of this study was to determine the therapeutic potential of Cpl-1 in a mouse model of severe pneumococcal pneumonia. Controlled, in vivo laboratory study. Female C57/Bl6 mice, 8-12 weeks old. Mice were transnasally infected with pneumococci and therapeutically treated with Cpl-1 or amoxicillin by intraperitoneal injections starting 24 or 48 hours after infection. Judged from clinical appearance, decreased body weight, reduced dynamic lung compliance and Pao2/Fio2 ratio, and morphologic changes in the lungs, mice suffered from severe pneumonia at the onset of therapy. When treatment was commenced 24 hours after infection, 100% Cpl-1-treated and 86% amoxicillin-treated mice survived otherwise fatal pneumonia and showed rapid recovery. When treatment was started 48 hours after infection, mice had developed bacteremia, and three of seven (42%) Cpl-1-treated and five of seven (71%) amoxicillin-treated animals survived. Cpl-1 dramatically reduced pulmonary bacterial counts, and prevented bacteremia, systemic hypotension, and lactate increase when treatment commenced at 24 hours. In vivo, treatment with Cpl-1 or amoxicillin effectively reduced counts of penicillin-susceptible pneumococci. The inflammatory response in Cpl-1-and amoxicillin-treated mice was lower than in untreated mice, as determined by multiplex cytokine assay of lung and blood samples. In human epithelial cell cultures, lysed bacteria evoked less proinflammatory cytokine release and cell death, as compared with viable bacteria. Cpl-1 may provide a new therapeutic option in the treatment of pneumococcal pneumonia.
    No preview · Article · Jan 2010 · Critical care medicine
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    ABSTRACT: Severe pneumococcal pneumonia frequently causes respiratory failure. Both pathogen factors and an uncontrolled host response may contribute to acute lung injury by impairing microvascular barrier function. Phosphodiesterase 2 (PDE2) was examined as a potential target in pneumonia-induced lung microvascular hyperpermeability. Controlled, in vitro, ex vivo, and in vivo laboratory study. Female Balb/C and C57Bl/6 mice, 8-12 weeks old. Human umbilical vein endothelial cells and isolated mouse lungs were challenged with the pneumococcal exotoxin pneumolysin in the presence or absence of the selective PDE2 inhibitors 9-(6-phenyl-2-oxohex-3-yl)-2-(3,4-dimethoxybenzyl)-purin-6one (PDP) or hydroxy-PDP. Transcellular electrical resistance or human serum albumin leakage in bronchoalveolar lavage fluid was determined, respectively. In addition, we induced pneumococcal pneumonia in mice and treated with hydroxy-PDP via continuous subcutaneous application by osmotic pumps. Human serum albumin leakage in bronchoalveolar lavage fluid was measured 48 hours after transnasal infection, and lung specimens were analyzed by TaqMan real-time polymerase chain reaction and Western blot for PDE2 gene and protein expression. In isolated perfused mouse lungs and in human umbilical vein endothelial cell monolayers, selective inhibition of PDE2 markedly decreased pneumolysin-induced hyperpermeability. Furthermore, in murine pneumococcal pneumonia, pulmonary PDE2-mRNA and -protein expression was significantly increased, and pneumonia-induced vascular permeability was distinctively reduced by PDE2 inhibition. PDE2 inhibition diminished microvascular leakage in pneumococcal pneumonia, and pulmonary PDE2 upregulation may play a crucial role in this respect. Selective PDE2 inhibitors thus may offer a promising therapeutic approach in severe pneumococcal pneumonia.
    No preview · Article · Jan 2010 · Critical care medicine
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    ABSTRACT: Different NOD-like receptors, including NLRP1, NLRP3, and NLRC4, as well as the recently identified HIN-200 protein, AIM2, form multiprotein complexes called inflammasomes, which mediate caspase-1-dependent processing of pro-IL-1beta. Listeria monocytogenes is an intracellular pathogen that is actively phagocytosed by monocytes/macrophages and subsequently escapes from the phagosome into the host cell cytosol, depending on its pore-forming toxin listeriolysin O (LLO). In this study, we demonstrate that human PBMCs produced mature IL-1beta when infected with wild-type L. monocytogenes or when treated with purified LLO. L. monocytogenes mutants lacking LLO or expressing a noncytolytic LLO as well as the avirulent Listeria innocua induced strongly impaired IL-1beta production. RNA interference and inhibitor experiments in human PBMCs as well as experiments in Nlrp3 and Rip2 knockout bone marrow-derived macrophages demonstrated that the Listeria-induced IL-1beta release was dependent on ASC, caspase-1, and NLRP3, whereas NOD2, Rip2, NLRP1, NLRP6, NLRP12, NLRC4, and AIM2 appeared to be dispensable. We found that L. monocytogenes-induced IL-1beta production was largely dependent on phagosomal acidification and cathepsin B release, whereas purified LLO activated an IL-1beta production independently of these mechanisms. Our results indicate that L. monocytogenes-infected human PBMCs produced IL-1beta, largely depending on an LLO-mediated phagosomal rupture and cathepsin B release, which is sensed by Nlrp3. In addition, an LLO-dependent but cathepsin B-independent NLRP3 activation might contribute to some extent to the IL-1beta production in L. monocytogenes-infected cells.
    Full-text · Article · Dec 2009 · The Journal of Immunology
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    ABSTRACT: Activation of the endothelium by oxidized low-density lipoprotein (oxLDL) has been implicated in the development of atherosclerosis. Histone modifications impact on the transcriptional activity state of genes. We tested the hypothesis that oxLDL-induced inflammatory gene expression is regulated by histone modifications and experienced the effect of statins on these alterations. OxLDL-related interleukin-8 (IL-8) and monocyte-chemoattractant protein-1 (MCP-1) secretion in endothelial cells was reduced by statins but enhanced by histone deacetylase inhibitors. OxLDL induced lectin-like oxidized LDL receptor-1 (LOX-1) and extracellular regulated kinases (ERK1/2)-dependent acetylation of histone H3 and H4 as well as phosphorylation of histone H3, both globally and on the promoters of il8 and mcp1. Pretreatment of oxLDL-exposed cells with statins reduced the above mentioned histone modification, as well as recruitment of CREB binding protein (CBP) 300, NF-kappaB, and of RNA polymerase II but prevented loss of binding of histone deacetylase (HDAC)-1 and -2 at the il8 and mcp1 gene promoters. OxLDL reduced HDAC1 and 2 expression, and statins partly restored global HDAC-activity. Statin-related effects were reverted with mevalonate. In situ experiments indicated decreased expression of HDAC2 in endothelial cells in atherosclerotic plaques of human coronary arteries. Histone modifications seem to play an important role in atherosclerosis.
    Preview · Article · Feb 2009 · Arteriosclerosis Thrombosis and Vascular Biology
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    ABSTRACT: The nucleotide-binding domain and leucine-rich repeat containing protein NOD2 serves as a cytoplasmic pattern recognition molecule sensing bacterial muramyl dipeptide (MDP), whereas TLR2 mediates cell surface recognition of bacterial lipopeptides. In this study, we show that NOD2 stimulation activated Rac1 in human THP-1 cells and primary human monocytes. Rac1 inhibition or knock-down, or actin cytoskeleton disruption increased MDP-stimulated IL-8 secretion and NF-kappaB activation, whereas TLR2-dependent cell activation was suppressed by Rac1 inhibition. p21-activated kinase [Pak]-interacting exchange factor (beta-PIX) plays a role in this negative regulation, because knock-down of beta-PIX also led to increased NOD2-mediated but not TLR2-mediated IL-8 secretion, and coimmunoprecipitation experiments demonstrated that NOD2 interacted with beta-PIX as well as Rac1 upon MDP stimulation. Moreover, knock-down of beta-PIX or Rac1 abrogated membrane recruitment of NOD2, and interaction of NOD2 with its negative regulator Erbin. Overall, our data indicate that beta-PIX and Rac1 mediate trafficking and negative regulation of NOD2-dependent signaling which is different from Rac1's positive regulatory role in TLR2 signaling.
    Full-text · Article · Sep 2008 · The Journal of Immunology
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    ABSTRACT: Legionella pneumophila causes severe pneumonia. Acetylation of histones is thought to be an important regulator of gene transcription, but its impact on L. pneumophila-induced expression of proinflammatory cytokines is unknown. L. pneumophila strain 130b induced the expression of the important chemoattractant IL-8 and genome-wide histone modifications in human lung epithelial A549 cells. We analyzed the IL-8-promoter and found that histone H4 was acetylated and H3 was phosphorylated at Ser(10) and acetylated at Lys(14), followed by transcription factor NF-kappaB. Recruitment of RNA polymerase II to the IL-8 promoter corresponded with increases in gene transcription. Histone modification and IL-8 release were dependent on p38 kinase and NF-kappaB pathways. Legionella-induced IL-8 expression was decreased by histone acetylase (HAT) inhibitor anacardic acid and enhanced by histone deacetylase (HDAC) inhibitor trichostatin A. After Legionella infection, HATs p300 and CREB-binding protein were time-dependently recruited to the IL-8 promoter, whereas HDAC1 and HDAC5 first decreased and later reappeared at the promoter. Legionella specifically induced expression of HDAC5 but not of other HDACs in lung epithelial cells, but knockdown of HDAC1 or 5 did not alter IL-8 release. Furthermore, Legionella-induced cytokine release, promoter-specific histone modifications, and RNA polymerase II recruitment were reduced in infection with flagellin-deletion mutants. Legionella-induced histone modification as well as HAT-/HDAC-dependent IL-8 release could also be shown in primary lung epithelial cells. In summary, histone acetylation seems to be important for the regulation of proinflammatory gene expression in L. pneumophila infected lung epithelial cells. These pathways may contribute to the host response in Legionnaires' disease.
    Full-text · Article · Aug 2008 · The Journal of Immunology
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    ABSTRACT: Airway hyperresponsiveness (AHR) is a hallmark of bronchial asthma. Increased expression of smooth muscle contractile proteins or increased responsiveness of the contractile apparatus due to RhoA/Rho-kinase activation may contribute to AHR. BALB/c mice developed AHR following systemic sensitization by intraperitoneal injections of 20 microg ovalbumin (OVA) in presence of 2mg Al(OH)(3) on days 1 and 14, and airway challenge by 1% OVA-inhalation for 20 min each on days 28, 29 and 30. As assessed by Western blot, protein expression of RhoA, MLC (myosin light chain) and smMLCK (smooth muscle myosin light chain kinase) was increased in lungs of OVA/OVA-animals with AHR, as well as in lungs of OVA-sensitized and sham-challenged animals (OVA/PBS) without AHR, compared with lungs of PBS/PBS-animals. Pretreatment with the specific Rho-kinase inhibitor Y-27632 reduced MLC-phosphorylation and AHR. Contribution of Rho-kinase to bronchoconstriction was increased in lungs of OVA/OVA-animals compared with OVA/PBS- and PBS/PBS-animals, respectively. Furthermore, bronchoconstriction following MCh stimulation was significantly reduced after Y-27632 application. In conclusion, systemic allergen-sensitization increased pulmonary expression of proteins involved in smooth muscle contraction, which may contribute to development of AHR. However, this observation was independent from local allergen challenge, suggesting that additional cofactors may be required for the activation of Rho-kinase and thereby the induction of AHR. Rho-kinase may play an important role in murine AHR, and the bronchodilating action of Rho-kinase inhibition may offer a new therapeutic perspective in obstructive airway disease.
    No preview · Article · Jul 2008 · Experimental and Toxicologic Pathology
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    ABSTRACT: Secretion of effector molecules is one of the major mechanisms by which the intracellular human pathogen Legionella pneumophila interacts with host cells during infection. Specific secretion machineries which are responsible for the subfraction of secreted proteins (soluble supernatant proteins [SSPs]) and the production of bacterial outer membrane vesicles (OMVs) both contribute to the protein composition of the extracellular milieu of this lung pathogen. Here we present comprehensive proteome reference maps for both SSPs and OMVs. Protein identification and assignment analyses revealed a total of 181 supernatant proteins, 107 of which were specific to the SSP fraction and 33 of which were specific to OMVs. A functional classification showed that a large proportion of the identified OMV proteins are involved in the pathogenesis of Legionnaires' disease. Zymography and enzyme assays demonstrated that the SSP and OMV fractions possess proteolytic and lipolytic enzyme activities which may contribute to the destruction of the alveolar lining during infection. Furthermore, it was shown that OMVs do not kill host cells but specifically modulate their cytokine response. Binding of immunofluorescently stained OMVs to alveolar epithelial cells, as visualized by confocal laser scanning microscopy, suggested that there is delivery of a large and complex group of proteins and lipids in the infected tissue in association with OMVs. On the basis of these new findings, we discuss the relevance of protein sorting and compartmentalization of virulence factors, as well as environmental aspects of the vesicle-mediated secretion.
    Full-text · Article · Jun 2008 · Infection and immunity

Publication Stats

2k Citations
246.85 Total Impact Points

Institutions

  • 2013
    • Universitätsklinikum Gießen und Marburg
      Marburg, Hesse, Germany
    • Philipps University of Marburg
      Marburg, Hesse, Germany
  • 2005-2012
    • Charité Universitätsmedizin Berlin
      Berlín, Berlin, Germany
    • Freie Universität Berlin
      • Medical School - Charité
      Berlín, Berlin, Germany
  • 2008
    • Technische Universität Braunschweig
      • Institute of Microbiology
      Brunswyck, Lower Saxony, Germany
  • 2002-2003
    • Humboldt-Universität zu Berlin
      Berlín, Berlin, Germany