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Holger Christian Müller,
Andreas Christian Hocke,
Katharina Hellwig,
Birgitt Gutbier,
Harm Peters,
Stefanie Maria Schönrock,
Thomas Tschernig,
Andreas Schmiedl,
Stefan Hippenstiel,
Philippe Dje N'Guessan, Simone Rosseau,
Norbert Suttorp,
Martin Witzenrath
[show abstract]
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ABSTRACT: Lung barrier protection by Sphingosine-1 Phosphate (S1P) has been demonstrated experimentally, but recent evidence suggests barrier disruptive properties of high systemic S1P concentrations. The S1P analog FTY720 recently gained an FDA approval for treatment of multiple sclerosis. In case of FTY720 treated patients experiencing multiple organ dysfunction syndrome the drug may accumulate due to liver failure, and the patients may receive ventilator therapy. Whereas low doses of FTY720 enhanced endothelial barrier function, data on effects of increased FTY720 concentrations are lacking. We measured transcellular electrical resistance (TER) of human umbilical vein endothelial cell (HUVEC) monolayers, performed morphologic analysis and measured apoptosis by TUNEL staining and procaspase-3 degradation in HUVECs stimulated with FTY720 (0.01-100 μM). Healthy C57BL/6 mice and mice ventilated with 17 ml/kg tidal volume and 100% oxygen for 2 h were treated with 0.1 or 2 mg/kg FTY720 or solvent, and lung permeability, oxygenation and leukocyte counts in BAL and blood were quantified. Further, electron microscopic analysis of lung tissue was performed. We observed barrier protective effects of FTY720 on HUVEC cell layers at concentrations up to 1 μM while higher concentrations induced irreversible barrier breakdown accompanied by induction of apoptosis. Low FTY720 concentrations (0.1 mg/kg) reduced lung permeability in mechanically ventilated mice, but 2 mg/kg FTY720 increased pulmonary vascular permeability in ventilated mice accompanied by endothelial apoptosis, while not affecting permeability in non-ventilated mice. Moreover, hyperoxic mechanical ventilation sensitized the pulmonary vasculature to a barrier disrupting effect of FTY720, resulting in worsening of ventilator induced lung injury. In conclusion, the current data suggest FTY720 induced endothelial barrier dysfunction, which was probably caused by proapoptotic effects and enhanced by mechanical ventilation.
Pulmonary Pharmacology & Therapeutics 03/2011; 24(4):377-85. · 2.80 Impact Factor
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ABSTRACT: Mechanical ventilation (MV) is a life-saving intervention in acute respiratory failure without any alternative. However, even protective ventilation strategies applying minimal mechanical stress may evoke ventilator-induced lung injury (VILI). Adjuvant pharmacological strategies in addition to lung-protective ventilation to attenuate VILI are lacking. Adrenomedullin exhibited endothelial barrier-stabilising properties in vitro and in vivo.
In untreated mice (female C57/Bl6 mice, 11-15 weeks old) and animals treated with adrenomedullin, lung permeability, local and systemic inflammation and markers of distal organ function were assessed following 2 or 6 h of mechanical ventilation with 100% oxygen and protective or moderately injurious ventilator settings, respectively.
Adrenomedullin dramatically reduced lung permeability in VILI in mice, leading to improved oxygenation. Adrenomedullin treatment reduced myosin light chain phosphorylation, attenuated the accumulation of leucocytes in the lung and prevented the increase in lactate and creatinine levels in mice ventilated with high tidal volumes. Moreover, adrenomedullin protected against VILI even when treatment was initiated 2 h after the beginning of mechanical ventilation in a 6 h VILI mouse model.
Adjuvant treatment with adrenomedullin may be a promising new pharmacological approach to attenuate VILI.
Thorax 10/2010; 65(12):1077-84. · 6.84 Impact Factor
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Holger C Müller,
Katharina Hellwig, Simone Rosseau,
Thomas Tschernig,
Andreas Schmiedl,
Birgitt Gutbier,
Bernd Schmeck,
Stefan Hippenstiel,
Harm Peters,
Lars Morawietz,
Norbert Suttorp,
Martin Witzenrath
[show abstract]
[hide abstract]
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.
Critical care (London, England) 01/2010; 14(4):R143. · 4.61 Impact Factor
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Martin Witzenrath,
Bernd Schmeck,
Jan M Doehn,
Thomas Tschernig,
Janine Zahlten,
Jutta M Loeffler,
Maren Zemlin,
Holger Müller,
Birgitt Gutbier,
Hartwig Schütte,
Stefan Hippenstiel,
Vincent A Fischetti,
Norbert Suttorp, Simone Rosseau
[show abstract]
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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.
Critical care medicine 01/2010; 37(2):642-9. · 6.37 Impact Factor
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Martin Witzenrath,
Birgitt Gutbier,
Bernd Schmeck,
Herrmann Tenor,
Joachim Seybold,
Raimund Kuelzer,
Guido Grentzmann,
Armin Hatzelmann,
Vincent van Laak,
Thomas Tschernig,
Timothy J Mitchell,
Christian Schudt, Simone Rosseau,
Norbert Suttorp,
Hartwig Schütte
[show abstract]
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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.
Critical care medicine 01/2010; 37(2):584-90. · 6.37 Impact Factor
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ABSTRACT: The resistance of epithelial cells infected with Chlamydophila pneumoniae for apoptosis has been attributed to the induced expression and increased stability of anti-apoptotic proteins called inhibitor of apoptosis proteins (IAPs). The significance of cellular inhibitor of apoptosis protein-1 (cIAP-1) in C. pneumoniae pulmonary infection and innate immune response was investigated in cIAP-1 knockout (KO) mice using a novel non-invasive intra-tracheal infection method. In contrast to wildtype, cIAP-1 knockout mice failed to clear the infection from their lungs. Wildtype mice responded to infection with a strong inflammatory response in the lung. In contrast, the recruitment of macrophages was reduced in cIAP-1 KO mice compared to wildtype mice. The concentration of Interferon gamma (IFN-gamma) was increased whereas that of Tumor Necrosis Factor (TNF-alpha) was reduced in the lungs of infected cIAP-1 KO mice compared to infected wildtype mice. Ex vivo experiments on mouse peritoneal macrophages and splenocytes revealed that cIAP-1 is required for innate immune responses of these cells. Our findings thus suggest a new immunoregulatory role of cIAP-1 in the course of bacterial infection.
PLoS ONE 02/2009; 4(8):e6519. · 4.09 Impact Factor
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Katrin Reppe,
Thomas Tschernig,
Anke Lührmann,
Vincent van Laak,
Karsten Grote,
Maren V Zemlin,
Birgitt Gutbier,
Holger C Müller,
Mischo Kursar,
Hartwig Schütte, Simone Rosseau,
Reinhard Pabst,
Norbert Suttorp,
Martin Witzenrath
[show abstract]
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ABSTRACT: Community-acquired pneumonia (CAP) is associated with high morbidity and mortality, and Streptococcus pneumoniae is the most prevalent causal pathogen identified in CAP. Impaired pulmonary host defense increases susceptibility to pneumococcal pneumonia. S. pneumoniae may up-regulate Toll-like receptor (TLR)-2 expression and activate TLR-2, contributing to pneumococcus-induced immune responses. In the current study, the course of severe murine pneumococcal pneumonia after pulmonary TLR-2-mediated immunostimulation with synthetic macrophage-activating lipopeptide-2 (MALP-2) was examined. Intratracheal MALP-2 application evoked enhanced proinflammatory cytokine and chemokine release, resulting in recruitment of polymorphonuclear neutrophils (PMN), macrophages, and lymphocytes into the alveolar space in WT, but not in TLR-2-deficient mice. In murine lungs as well as in human alveolar epithelial cells (A549), MALP-2 increased TLR-2 expression at both mRNA and protein level. Blood leukocyte numbers and populations remained unchanged. MALP-2 application 24 hours before intranasal pneumococcal infection resulted in increased levels of CCL5 associated with augmented leukocyte recruitment, and decreased levels of anti-inflammatory IL-10 in bronchoalveolar lavage fluid. Clinically, MALP-2-treated as compared with untreated mice showed increased survival, reduced hypothermia, and increased body weight. MALP-2 also reduced bacteremia and improved bacterial clearance in lung parenchyma, as examined by immunohistochemistry. In conclusion, pulmonary immunostimulation with MALP-2 before infection with S. pneumoniae improved local host defense and increased survival in murine pneumococcal pneumonia.
American Journal of Respiratory Cell and Molecular Biology 11/2008; 40(4):474-81. · 5.13 Impact Factor
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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.
Experimental and Toxicologic Pathology 07/2008; 60(1):9-15. · 2.78 Impact Factor
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Martin Witzenrath,
Birgitt Gutbier,
John S Owen,
Bernd Schmeck,
Timothy J Mitchell,
Konstantin Mayer,
Michael J Thomas,
Satoshi Ishii, Simone Rosseau,
Norbert Suttorp,
Hartwig Schütte
[show abstract]
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ABSTRACT: Acute respiratory failure is a major complication of severe pneumococcal pneumonia, characterized by impairment of pulmonary microvascular barrier function and pulmonary hypertension. Both features can be evoked by pneumolysin (PLY), an important virulence factor of Streptococcus pneumoniae. We hypothesized that platelet-activating factor (PAF) and associated downstream signaling pathways play a role in the PLY-induced development of acute lung injury.
Controlled, ex vivo laboratory study.
Female Balb/C mice, 8-12 wks old.
Ventilated and blood-free-perfused lungs of wild-type and PAF receptor-deficient mice were challenged with recombinant PLY.
Intravascular PLY, but not the pneumolysoid Pd-B (PLY with a Trp-Phe substitution at position 433), caused an impressive dose-dependent increase in pulmonary vascular resistance and increased PAF in lung homogenates, as detected by reversed-phase high-performance liquid chromatography coupled to tandem mass spectrometry. The pressor response was reduced in lungs of PAF receptor-deficient mice and after PAF receptor blockade by BN 50730. PLY and exogenous PAF increased thromboxane B2 in lung effluate, and thromboxane receptor inhibition by BM 13505 diminished the pressor response to PLY. Differential inhibition of intracellular signaling steps suggested significant contribution of phosphatidylcholine-specific phospholipase C and protein kinase C and of the Rho/Rho-kinase pathway to PLY-induced pulmonary vasoconstriction. Unrelated to the pulmonary arterial pressor response, microvascular leakage of PLY was diminished in lungs of PAF receptor-deficient mice as well.
PAF significantly contributed to PLY-induced acute injury in murine lungs. The PAF-mediated pressor response to PLY depends on thromboxane and on the downstream effectors phosphatidylcholine-specific phospholipase C, protein kinase C, and Rho-kinase.
Critical Care Medicine 08/2007; 35(7):1756-62. · 6.33 Impact Factor
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Andreas C Hocke,
Matthias P Lampe,
Martin Witzenrath,
Hans Mollenkopf,
Jens Zerrahn,
Bernd Schmeck,
Ulrich Kessler,
Matthias Krüll,
Sven Hammerschmidt,
Stefan Hippenstiel,
Hartwig Schütte,
Norbert Suttorp, Simone Rosseau
[show abstract]
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ABSTRACT: Interleukin (IL)-15 has critical impact on the homeostasis and activation of natural killer cells, natural killer T cells, gammadeltaT cells, and CD8(+)T cells, and contributes to antimicrobial defenses particularly at mucosal sites. The respiratory tract comprises a large mucosal surface and harbors significant amounts of lymphocytes, however the expression pattern of IL-15 in the lung and its role in local immune responses are largely unknown. We therefore analyzed the differential expression of IL-15 and the IL-15 receptor (IL-15R) complex in the lungs of mice and demonstrated substantial constitutive expression in bronchial and alveolar epithelial cells, alveolar macrophages, and vascular smooth muscle cells, implicating contribution to pulmonary immune cell homeostasis already under normal conditions. The induction of pneumococcal pneumonia but not the infection with Chlamydophila pneumoniae evoked a significant up-regulation of IL-15 on alveolar macrophages and bronchial epithelial cells, with the latter presenting de-novo expression of IL-15 on their basolateral surface and additional up-regulation of IL-15Ralpha. Moreover, transcriptome analysis as well as semi-quantitative PCR indicated at least partial transcriptional regulation in mice lungs. In conclusion IL-15 is suggested being of functional importance in the pulmonary immune response against pneumococcal pneumonia.
Cytokine 06/2007; 38(2):61-73. · 3.02 Impact Factor
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[show abstract]
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ABSTRACT: Pneumonia is the most common cause of death from infectious disease in the western hemisphere. Pathophysiological and protective processes are initiated by pattern recognition of microbial structures. To provide the molecular framework for a better understanding of processes relevant to host defence in pneumonia, we performed pulmonary transcriptome analysis in mice infected with the major bacterial and viral agents of community-acquired pneumonia, Streptococcus pneumoniae and influenza A virus. We detected differential expression of 1300 genes after infection with either pathogen. Of these, approximately 36% or 30% were specific for pneumococcal or influenza infection, respectively, yielding pathogen-specific as well as shared inflammatory transcriptional signatures. These results not only reveal a differential response on the cytokine and chemokine levels but also emphasize the important role of genes implicated in regulation and fine tuning of inflammation. As one, albeit unexpected, key feature of pneumococcal pneumonia we discovered down-regulation of B-cell responses, probably reflecting a pneumococcal virulence strategy. The pathophysiological consequences of influenza A virus infection were reflected by the emerging protective T-cell response and differential induction of genes involved in tissue regeneration and proliferation. These data provide new insights into pathogenesis of the most common forms of pneumonia, highlighting the value of transcriptional profiling for the elucidation of underlying mechanisms.
Immunology 04/2007; 120(3):380-91. · 3.32 Impact Factor
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[show abstract]
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ABSTRACT: Airway hyperresponsiveness (AHR) is a hallmark of bronchial asthma. Important features of this exaggerated response to bronchoconstrictive stimuli have mostly been investigated in vivo in intact animals or in vitro in isolated tracheal or bronchial tissues. Both approaches have important advantages but also certain limitations. Therefore, the aim of our study was to develop an ex vivo model of isolated lungs from sensitized mice for the investigation of airway responsiveness (AR). BALB/c mice were sensitized by intraperitoneal ovalbumin (Ova) and subsequently challenged by Ova inhalation. In vivo AR was measured in unrestrained animals by whole body plethysmography after stimulation with aerosolized methacholine (MCh) with determination of enhanced pause (P(enh)). Twenty-four hours after each P(enh) measurement, airway resistance was continuously registered in isolated, perfused, and ventilated lungs on stimulation with inhaled or intravascular MCh or nebulized Ova. In a subset of experiments, in vivo AR was additionally measured in orotracheally intubated, spontaneously breathing mice 24 h after P(enh) measurement, and lungs were isolated further 24 h later. Isolated lungs of allergen-sensitized and -challenged mice showed increased AR after MCh inhalation or infusion as well as after specific provocation with aerosolized allergen. AR was increased on days 2 and 5 after Ova challenge and had returned to baseline on day 9. AHR in isolated lungs after aerosolized or intravascular MCh strongly correlated with in vivo AR. Pretreatment of isolated lungs with the beta(2)-agonist fenoterol diminished AR. In conclusion, this model provides new opportunities to investigate mechanisms of AHR as well as pharmacological interventions on an intact organ level.
AJP Lung Cellular and Molecular Physiology 10/2006; 291(3):L466-72. · 3.66 Impact Factor
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Martin Witzenrath,
Birgitt Gutbier,
Andreas C Hocke,
Bernd Schmeck,
Stefan Hippenstiel,
Katharina Berger,
Timothy J Mitchell,
Juan R de los Toyos, Simone Rosseau,
Norbert Suttorp,
Hartwig Schütte
[show abstract]
[hide abstract]
ABSTRACT: Acute respiratory failure is a significant complication of severe pneumococcal pneumonia. In a mouse model, we observed early-onset lung microvascular leakage after pulmonary infection with Streptococcus pneumoniae, and we hypothesized that the important virulence factor pneumolysin may be the direct causative agent.
Controlled, in vivo, ex vivo, and in vitro laboratory study.
Laboratory.
Female mice, 8-12 wks old.
Ventilated and blood-free perfused murine lungs were challenged with recombinant pneumolysin via the airways as well as via the vascular bed. In addition, we analyzed the impact of pneumolysin on electrical cell impedance and hydraulic conductivity of human umbilical vein endothelial cell (HUVEC) and alveolar epithelial cell (A549) monolayers.
Aerosolized pneumolysin dose-dependently increased capillary permeability with formation of severe lung edema but did not affect pulmonary vascular resistance. Intravascular pneumolysin caused an impressive dose-dependent increase in pulmonary vascular resistance and in lung microvascular permeability. By immunohistochemistry, pneumolysin was detected mainly in endothelial cells of pulmonary arterial vessels, which concomitantly displayed strong vasoconstriction. Moreover, pneumolysin increased permeability of HUVEC and A549 monolayers. Interestingly, immunofluorescence of endothelial cell monolayers exposed to pneumolysin showed gap formation and moderate stress fiber generation.
Pneumolysin may play a central role for early-onset acute lung injury due to severe pneumococcal pneumonia by causing impairment of pulmonary microvascular barrier function and severe pulmonary hypertension.
Critical Care Medicine 08/2006; 34(7):1947-54. · 6.33 Impact Factor
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[show abstract]
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ABSTRACT: Omalizumab is a recombinant monoclonal anti-IgE antibody with proven efficacy in allergic diseases and further anti-inflammatory potency in the treatment of asthma.
To explore the anti-inflammatory mechanism of omalizumab, we investigated the induction of immunologic changes leading to eosinophil apoptosis and examined T-lymphocyte cytokine profiles in patients with allergic asthma.
Nineteen patients with allergic asthma were enrolled and received omalizumab at a dose of at least 0.016 mg/kg/IgE (IU/mL) every 4 weeks. Peripheral eosinophils and T-lymphocyte cytokine profiles were evaluated by fluorescence-activated cell sorting before treatment (baseline), at 12 weeks of treatment, and 12 weeks after discontinuation of treatment with omalizumab or placebo.
Markers of eosinophil apoptosis (Annexin V) were significantly increased in omalizumab recipients compared with placebo, whereas no changes in markers of necrosis (7-amino-actinomycin) or eosinophil activation CD69 or Fas receptor (CD95) were detected. GM-CSF+ lymphocytes were reduced in omalizumab recipients compared with placebo. Fewer IL-2+ and IL-13+ lymphocytes were evident in omalizumab recipients than in the placebo group. There were no significant differences in IL-5, IFN-gamma, or TNF-alpha between the omalizumab and placebo groups.
These findings provide further evidence that omalizumab has additional anti-inflammatory activity demonstrated by induction of eosinophil apoptosis and downregulation of the inflammatory cytokines IL-2 and IL-13. Further studies are needed to determine the underlying mechanisms.
These findings support the critical role of IgE in the regulation of inflammation in allergic asthma: influencing the inflammation is the key to control the more severe type of asthma.
Journal of Allergy and Clinical Immunology 07/2006; 117(6):1493-9. · 11.00 Impact Factor
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Philippe Dje N'Guessan,
Stefan Hippenstiel,
Mirabelle O Etouem,
Janine Zahlten,
Wiebke Beermann,
David Lindner,
Bastian Opitz,
Martin Witzenrath, Simone Rosseau,
Norbert Suttorp,
Bernd Schmeck
[show abstract]
[hide abstract]
ABSTRACT: Streptococcus pneumoniae is a major cause of community-acquired pneumonia and death from infectious diseases in industrialized countries. Lung airway and alveolar epithelial cells comprise an important barrier against airborne pathogens. Cyclooxygenase (COX)-derived prostaglandins, such as PGE(2), are considered to be important regulators of lung function. Herein, we tested the hypothesis that pneumococci induced COX-2-dependent PGE(2) production in pulmonary epithelial cells. Pneumococci-infected human pulmonary epithelial BEAS-2B cells released PGE(2). Expression of COX-2 but not COX-1 was dose and time dependently increased in S. pneumoniae-infected BEAS-2B cells as well as in lungs of mice with pneumococcal pneumonia. S. pneumoniae induced degradation of IkappaBalpha and DNA binding of NF-kappaB. A specific peptide inhibitor of the IkappaBalpha kinase complex blocked pneumococci-induced PGE(2) release and COX-2 expression. In addition, we noted activation of p38 MAPK and JNK in pneumococci-infected BEAS-2B cells. PGE(2) release and COX-2 expression were reduced by p38 MAPK inhibitor SB-202190 but not by JNK inhibitor SP-600125. We analyzed interaction of kinase pathways and NF-kappaB activation: dominant-negative mutants of p38 MAPK isoforms alpha, beta(2), gamma, and delta blocked S. pneumoniae-induced NF-kappaB activation. In addition, recruitment of NF-kappaB subunit p65/RelA and RNA polymerase II to the cox2 promoter depended on p38 MAPK but not on JNK activity. In summary, p38 MAPK- and NF-kappaB-controlled COX-2 expression and subsequent PGE(2) release by lung epithelial cells may contribute significantly to the host response in pneumococcal pneumonia.
AJP Lung Cellular and Molecular Physiology 07/2006; 290(6):L1131-8. · 3.66 Impact Factor
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Bernd Schmeck,
Sylvia Huber,
Kerstin Moog,
Janine Zahlten,
Andreas C Hocke,
Bastian Opitz,
Sven Hammerschmidt,
Tim J Mitchell,
Michael Kracht, Simone Rosseau,
Norbert Suttorp,
Stefan Hippenstiel
[show abstract]
[hide abstract]
ABSTRACT: Streptococcus pneumoniae is the major pathogen of community-acquired pneumonia. The respiratory epithelium constitutes the first line of defense against invading lung pathogens, including pneumococci. We analyzed the involvement of Toll-like receptors (TLR) and Rho-GTPase signaling in the activation of human lung epithelial cells by pneumococci. S. pneumoniae induced release of interleukin-8 (IL-8) by human bronchial epithelial cell line BEAS-2B. Specific inhibition of Rac1 by Nsc23766 or a dominant-negative mutant of Rac1 strongly reduced cytokine release. In addition, pneumococci-related cell activation (IL-8 release, NF-kappaB-activation) depended on MyD88, phosphatidylinositol 3-kinase, and Cdc42 but not on RhoA. Pneumococci enhanced TLR1 and TLR2 mRNA expression in BEAS-2B cells, whereas TLR4 and TLR6 expression was constitutively high. TLR1 and 2 synergistically recognized pneumococci in cotransfection experiments. TLR4, TLR6, LPS-binding protein, and CD14 seem not to be involved in pneumococci-dependent cell activation. At the IL-8 gene promoter, recruitment of phosphorylated NF-kappaB subunit p65 was blocked by inhibition of Rac1, whereas binding of the phosphorylated activator protein-1 subunit c-Jun to the promoter was not diminished. In summary, these results suggest that S. pneumoniae activate human epithelial cells by TLR1/2 and a phosphatidylinositol 3-kinase- and Rac1-dependent NF-kappaB-recruitment to the IL-8 promoter.
AJP Lung Cellular and Molecular Physiology 05/2006; 290(4):L730-L737. · 3.66 Impact Factor
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Matthias Krüll,
Petra Bockstaller,
Frederik N Wuppermann,
Andrea C Klucken,
Jörg Mühling,
Bernd Schmeck,
Joachim Seybold,
Clemens Walter,
Matthias Maass, Simone Rosseau,
Johannes H Hegemann,
Norbert Suttorp,
Stefan Hippenstiel
[show abstract]
[hide abstract]
ABSTRACT: Chlamydophila pneumoniae is an important respiratory pathogen. In this study we characterized C. pneumoniae strain TW183-mediated activation of human small airway epithelial cells (SAEC) and the bronchial epithelial cell line BEAS-2B and demonstrated time-dependent secretion of granulocyte macrophage colony-stimulating factor (GM-CSF) upon stimulation. TW183 activated p38 mitogen-activated protein kinase (MAPK) in epithelial cells. Kinase inhibition by SB202190 blocked Chlamydia-mediated GM-CSF release on mRNA and protein levels. In addition, the chemical inhibitor as well as dominant-negative mutants of p38 MAPK isoforms p38alpha, beta2, and gamma inhibited C. pneumoniae-related NF-kappaB activation. In contrast, blocking of MAPK ERK, c-Jun kinase/JNK, or PI-3 Kinase showed no effect on Chlamydia-related epithelial cell GM-CSF release. Ultraviolet-inactivated pathogens as compared with viable bacteria induced a smaller GM-CSF release, suggesting that viable Chlamydiae were only partly required for a full effect. Presence of an antichlamydial outer membrane protein-A (OmpA) antibody reduced and addition of recombinant heat-shock protein 60 from C. pneumoniae (cHsp60, GroEL-1)-enhanced GM-CSF release, suggesting a role of these proteins in epithelial cell activation. Our data demonstrate that C. pneumoniae triggers an early proinflammatory signaling cascade involving p38 MAPK-dependent NF-kappaB activation, resulting in subsequent GM-CSF release. C. pneumoniae-induced epithelial cytokine liberation may contribute significantly to inflammatory airway diseases like chronic obstructive pulmonary disease (COPD) or bronchial asthma.
American Journal of Respiratory Cell and Molecular Biology 04/2006; 34(3):375-82. · 5.13 Impact Factor
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Ulrike Fiedler,
Yvonne Reiss,
Marion Scharpfenecker,
Verena Grunow,
Stefanie Koidl,
Gavin Thurston,
Nicholas W Gale,
Martin Witzenrath, Simone Rosseau,
Norbert Suttorp,
Astrid Sobke,
Matthias Herrmann,
Klaus T Preissner,
Peter Vajkoczy,
Hellmut G Augustin
[show abstract]
[hide abstract]
ABSTRACT: The angiopoietins Ang-1 and Ang-2 have been identified as ligands of the receptor tyrosine kinase Tie-2 (refs. 1,2). Paracrine Ang-1-mediated activation of Tie-2 acts as a regulator of vessel maturation and vascular quiescence. In turn, the antagonistic ligand Ang-2 acts by an autocrine mechanism and is stored in endothelial Weibel-Palade bodies from where it can be rapidly released upon stimulation. The rapid release of Ang-2 implies functions of the angiopoietin-Tie system beyond its established role during vascular morphogenesis as a regulator of rapid vascular responses. Here we show that mice deficient in Ang-2 (encoded by the gene Angpt2) cannot elicit an inflammatory response in thioglycollate-induced or Staphylococcus aureus-induced peritonitis, or in the dorsal skinfold chamber model. Recombinant Ang-2 restores the inflammation defect in Angpt2(-/-) mice. Intravital microscopy showed normal TNF-alpha-induced leukocyte rolling in the vasculature of Angpt2(-/-)mice, but rolling cells did not firmly adhere to activated endothelium. Cellular experiments showed that Ang-2 promotes adhesion by sensitizing endothelial cells toward TNF-alpha and modulating TNF-alpha-induced expression of endothelial cell adhesion molecules. Together, these findings identify Ang-2 as an autocrine regulator of endothelial cell inflammatory responses. Ang-2 thereby acts as a switch of vascular responsiveness exerting a permissive role for the activities of proinflammatory cytokines.
Nature Medicine 03/2006; 12(2):235-9. · 22.46 Impact Factor
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ABSTRACT: Although pneumococcal pneumonia is one of the most common causes of death due to infectious diseases, little is known about pneumococci-lung cell interaction. Herein we tested the hypothesis that pneumococci activated pulmonary epithelial cell cytokine release by c-Jun-NH2-terminal kinase (JNK) METHODS: Human bronchial epithelial cells (BEAS-2B) or epithelial HEK293 cells were infected with S. pneumoniae R6x and cytokine induction was measured by RT-PCR, ELISA and Bioplex assay. JNK-phosphorylation was detected by Western blot and nuclear signaling was assessed by electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP). JNK was modulated by the small molecule inhibitor SP600125 and AP1 by transfection of a dominant negative mutant.
S. pneumoniae induced the release of distinct CC and CXC, as well as Th1 and Th2 cytokines and growth factors by human lung epithelial cell line BEAS-2B. Furthermore, pneumococci infection resulted in JNK phosphorylation in BEAS-2B cells. Inhibition of JNK by small molecule inhibitor SP600125 reduced pneumococci-induced IL-8 mRNA expression and release of IL-8 and IL-6. One regulator of the il8 promoter is JNK-phosphorylated activator protein 1 (AP-1). We showed that S. pneumoniae time-dependently induced DNA binding of AP-1 and its phosphorylated subunit c-Jun with a maximum at 3 to 5 h after infection. Recruitment of Ser63/73-phosphorylated c-Jun and RNA polymerase II to the endogenous il8 promoter was found 2 h after S. pneumoniae infection by chromatin immunoprecipitation. AP-1 repressor A-Fos reduced IL-8 release by TLR2-overexpressing HEK293 cells induced by pneumococci but not by TNFalpha. Antisense-constructs targeting the AP-1 subunits Fra1 and Fra2 had no inhibitory effect on pneumococci-induced IL-8 release.
S. pneumoniae-induced IL-8 expression by human epithelial BEAS-2B cells depended on activation of JNK and recruitment of phosphorylated c-Jun to the il8 promoter.
Respiratory research 02/2006; 7:98. · 3.36 Impact Factor
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ABSTRACT: Abstract
Background
Although pneumococcal pneumonia is one of the most common causes of death due to infectious diseases, little is known about pneumococci-lung cell interaction. Herein we tested the hypothesis that pneumococci activated pulmonary epithelial cell cytokine release by c-Jun-NH<sub>2</sub>-terminal kinase (JNK)
Methods
Human bronchial epithelial cells (BEAS-2B) or epithelial HEK293 cells were infected with S. pneumoniae R6x and cytokine induction was measured by RT-PCR, ELISA and Bioplex assay. JNK-phosphorylation was detected by Western blot and nuclear signaling was assessed by electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP). JNK was modulated by the small molecule inhibitor SP600125 and AP1 by transfection of a dominant negative mutant.
Results
S. pneumoniae induced the release of distinct CC and CXC, as well as Th1 and Th2 cytokines and growth factors by human lung epithelial cell line BEAS-2B. Furthermore, pneumococci infection resulted in JNK phosphorylation in BEAS-2B cells. Inhibition of JNK by small molecule inhibitor SP600125 reduced pneumococci-induced IL-8 mRNA expression and release of IL-8 and IL-6. One regulator of the il8 promoter is JNK-phosphorylated activator protein 1 (AP-1). We showed that S. pneumoniae time-dependently induced DNA binding of AP-1 and its phosphorylated subunit c-Jun with a maximum at 3 to 5 h after infection. Recruitment of Ser<sup>63/73</sup>-phosphorylated c-Jun and RNA polymerase II to the endogenous il8 promoter was found 2 h after S. pneumoniae infection by chromatin immunoprecipitation. AP-1 repressor A-Fos reduced IL-8 release by TLR2-overexpressing HEK293 cells induced by pneumococci but not by TNFα. Antisense-constructs targeting the AP-1 subunits Fra1 and Fra2 had no inhibitory effect on pneumococci-induced IL-8 release.
Conclusion
S. pneumoniae -induced IL-8 expression by human epithelial BEAS-2B cells depended on activation of JNK and recruitment of phosphorylated c-Jun to the il8 promoter.
Respiratory Research. 01/2006;
